2005-04-16 16:20:36 -06:00
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/*
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* linux/drivers/block/loop.c
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*
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* Written by Theodore Ts'o, 3/29/93
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*
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* DES encryption plus some minor changes by Werner Almesberger, 30-MAY-1993
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* more DES encryption plus IDEA encryption by Nicholas J. Leon, June 20, 1996
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*
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* Modularized and updated for 1.1.16 kernel - Mitch Dsouza 28th May 1994
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* Adapted for 1.3.59 kernel - Andries Brouwer, 1 Feb 1996
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*
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* Fixed do_loop_request() re-entrancy - Vincent.Renardias@waw.com Mar 20, 1997
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*
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* Added devfs support - Richard Gooch <rgooch@atnf.csiro.au> 16-Jan-1998
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*
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* Handle sparse backing files correctly - Kenn Humborg, Jun 28, 1998
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*
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* Loadable modules and other fixes by AK, 1998
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*
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* Make real block number available to downstream transfer functions, enables
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* CBC (and relatives) mode encryption requiring unique IVs per data block.
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* Reed H. Petty, rhp@draper.net
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*
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* Maximum number of loop devices now dynamic via max_loop module parameter.
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* Russell Kroll <rkroll@exploits.org> 19990701
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*
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* Maximum number of loop devices when compiled-in now selectable by passing
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* max_loop=<1-255> to the kernel on boot.
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2007-10-19 15:21:04 -06:00
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* Erik I. Bolsø, <eriki@himolde.no>, Oct 31, 1999
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2005-04-16 16:20:36 -06:00
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*
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* Completely rewrite request handling to be make_request_fn style and
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* non blocking, pushing work to a helper thread. Lots of fixes from
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* Al Viro too.
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* Jens Axboe <axboe@suse.de>, Nov 2000
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*
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* Support up to 256 loop devices
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* Heinz Mauelshagen <mge@sistina.com>, Feb 2002
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*
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* Support for falling back on the write file operation when the address space
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2008-10-29 15:00:55 -06:00
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* operations write_begin is not available on the backing filesystem.
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2005-04-16 16:20:36 -06:00
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* Anton Altaparmakov, 16 Feb 2005
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*
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* Still To Fix:
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* - Advisory locking is ignored here.
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* - Should use an own CAP_* category instead of CAP_SYS_ADMIN
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*
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/major.h>
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#include <linux/wait.h>
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#include <linux/blkdev.h>
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#include <linux/blkpg.h>
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#include <linux/init.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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2006-08-29 12:06:14 -06:00
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#include <linux/compat.h>
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2005-04-16 16:20:36 -06:00
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#include <linux/suspend.h>
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2007-07-17 05:03:35 -06:00
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#include <linux/freezer.h>
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2010-06-02 06:28:52 -06:00
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#include <linux/mutex.h>
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2005-04-16 16:20:36 -06:00
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#include <linux/writeback.h>
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#include <linux/completion.h>
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#include <linux/highmem.h>
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2006-09-29 02:59:11 -06:00
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#include <linux/kthread.h>
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2007-06-04 01:59:47 -06:00
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#include <linux/splice.h>
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2010-08-23 07:16:00 -06:00
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#include <linux/sysfs.h>
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loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
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#include <linux/miscdevice.h>
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2011-08-19 06:50:46 -06:00
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#include <linux/falloc.h>
|
2013-05-12 08:14:07 -06:00
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#include "loop.h"
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2005-04-16 16:20:36 -06:00
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#include <asm/uaccess.h>
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2011-07-31 14:08:04 -06:00
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static DEFINE_IDR(loop_index_idr);
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static DEFINE_MUTEX(loop_index_mutex);
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2005-04-16 16:20:36 -06:00
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loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
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static int max_part;
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static int part_shift;
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block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
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static struct workqueue_struct *loop_wq;
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|
2005-04-16 16:20:36 -06:00
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/*
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* Transfer functions
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*/
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static int transfer_none(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
|
2011-11-25 08:14:18 -07:00
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char *raw_buf = kmap_atomic(raw_page) + raw_off;
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char *loop_buf = kmap_atomic(loop_page) + loop_off;
|
2005-04-16 16:20:36 -06:00
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if (cmd == READ)
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memcpy(loop_buf, raw_buf, size);
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else
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memcpy(raw_buf, loop_buf, size);
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|
2011-11-25 08:14:18 -07:00
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kunmap_atomic(loop_buf);
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kunmap_atomic(raw_buf);
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2005-04-16 16:20:36 -06:00
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cond_resched();
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return 0;
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}
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static int transfer_xor(struct loop_device *lo, int cmd,
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struct page *raw_page, unsigned raw_off,
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struct page *loop_page, unsigned loop_off,
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int size, sector_t real_block)
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{
|
2011-11-25 08:14:18 -07:00
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char *raw_buf = kmap_atomic(raw_page) + raw_off;
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char *loop_buf = kmap_atomic(loop_page) + loop_off;
|
2005-04-16 16:20:36 -06:00
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char *in, *out, *key;
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int i, keysize;
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if (cmd == READ) {
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in = raw_buf;
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out = loop_buf;
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} else {
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in = loop_buf;
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out = raw_buf;
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}
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key = lo->lo_encrypt_key;
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keysize = lo->lo_encrypt_key_size;
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for (i = 0; i < size; i++)
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*out++ = *in++ ^ key[(i & 511) % keysize];
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|
2011-11-25 08:14:18 -07:00
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kunmap_atomic(loop_buf);
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kunmap_atomic(raw_buf);
|
2005-04-16 16:20:36 -06:00
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cond_resched();
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return 0;
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}
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static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
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{
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if (unlikely(info->lo_encrypt_key_size <= 0))
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return -EINVAL;
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return 0;
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}
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static struct loop_func_table none_funcs = {
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.number = LO_CRYPT_NONE,
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.transfer = transfer_none,
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};
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static struct loop_func_table xor_funcs = {
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.number = LO_CRYPT_XOR,
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.transfer = transfer_xor,
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.init = xor_init
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};
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/* xfer_funcs[0] is special - its release function is never called */
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static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
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&none_funcs,
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&xor_funcs
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};
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|
2011-11-16 01:21:49 -07:00
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static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
|
2005-04-16 16:20:36 -06:00
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{
|
2013-02-21 16:16:50 -07:00
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loff_t loopsize;
|
2005-04-16 16:20:36 -06:00
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/* Compute loopsize in bytes */
|
2013-02-21 16:16:50 -07:00
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loopsize = i_size_read(file->f_mapping->host);
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if (offset > 0)
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loopsize -= offset;
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/* offset is beyond i_size, weird but possible */
|
2011-11-16 01:21:49 -07:00
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if (loopsize < 0)
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return 0;
|
2005-04-16 16:20:36 -06:00
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|
2011-11-16 01:21:49 -07:00
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if (sizelimit > 0 && sizelimit < loopsize)
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loopsize = sizelimit;
|
2005-04-16 16:20:36 -06:00
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/*
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* Unfortunately, if we want to do I/O on the device,
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* the number of 512-byte sectors has to fit into a sector_t.
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*/
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return loopsize >> 9;
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}
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2011-11-16 01:21:49 -07:00
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static loff_t get_loop_size(struct loop_device *lo, struct file *file)
|
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{
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return get_size(lo->lo_offset, lo->lo_sizelimit, file);
|
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}
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|
2005-04-16 16:20:36 -06:00
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static int
|
2011-11-16 01:21:49 -07:00
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figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
|
2005-04-16 16:20:36 -06:00
|
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{
|
2011-11-16 01:21:49 -07:00
|
|
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loff_t size = get_size(offset, sizelimit, lo->lo_backing_file);
|
2005-04-16 16:20:36 -06:00
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|
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sector_t x = (sector_t)size;
|
2013-02-21 16:16:47 -07:00
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struct block_device *bdev = lo->lo_device;
|
2005-04-16 16:20:36 -06:00
|
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if (unlikely((loff_t)x != size))
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|
|
return -EFBIG;
|
2011-11-16 01:21:49 -07:00
|
|
|
if (lo->lo_offset != offset)
|
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|
|
lo->lo_offset = offset;
|
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|
|
if (lo->lo_sizelimit != sizelimit)
|
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|
|
lo->lo_sizelimit = sizelimit;
|
2007-05-08 01:28:20 -06:00
|
|
|
set_capacity(lo->lo_disk, x);
|
2013-02-21 16:16:47 -07:00
|
|
|
bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
|
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|
|
/* let user-space know about the new size */
|
|
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
2011-11-16 01:21:49 -07:00
|
|
|
return 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
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|
|
static inline int
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|
lo_do_transfer(struct loop_device *lo, int cmd,
|
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struct page *rpage, unsigned roffs,
|
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|
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struct page *lpage, unsigned loffs,
|
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|
|
int size, sector_t rblock)
|
|
|
|
{
|
|
|
|
if (unlikely(!lo->transfer))
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
|
|
|
|
}
|
|
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|
|
/**
|
|
|
|
* __do_lo_send_write - helper for writing data to a loop device
|
|
|
|
*
|
|
|
|
* This helper just factors out common code between do_lo_send_direct_write()
|
|
|
|
* and do_lo_send_write().
|
|
|
|
*/
|
2006-01-14 14:20:43 -07:00
|
|
|
static int __do_lo_send_write(struct file *file,
|
2006-10-10 15:45:07 -06:00
|
|
|
u8 *buf, const int len, loff_t pos)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
ssize_t bw;
|
|
|
|
mm_segment_t old_fs = get_fs();
|
|
|
|
|
2013-03-20 11:04:20 -06:00
|
|
|
file_start_write(file);
|
2005-04-16 16:20:36 -06:00
|
|
|
set_fs(get_ds());
|
|
|
|
bw = file->f_op->write(file, buf, len, &pos);
|
|
|
|
set_fs(old_fs);
|
2013-03-20 11:04:20 -06:00
|
|
|
file_end_write(file);
|
2005-04-16 16:20:36 -06:00
|
|
|
if (likely(bw == len))
|
|
|
|
return 0;
|
drivers/block/loop.c: ratelimit error messages
Metric tons of high speed spew is not helpful when things go pear shaped.
systemd lost its mind, forgot how to stop services it insists on being
sole manager of, massive printk() flood ensued, box eventually died.
[16206.684000] loop: Write error at byte offset 11412291584, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 13155434496, length 4096.
[16206.684000] loop: Write error at byte offset 13155438592, length 4096.
[16206.684000] loop: Write error at byte offset 13155442688, length 4096.
[16206.684000] loop: Write error at byte offset 13960736768, length 4096.
[16206.684000] loop: Write error at byte offset 14229172224, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 14766043136, length 4096.
[16206.684000] loop: Write error at byte offset 15034478592, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
Signed-off-by: Mike Galbraith <bitbucket@online.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-08 14:43:52 -06:00
|
|
|
printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",
|
2005-04-16 16:20:36 -06:00
|
|
|
(unsigned long long)pos, len);
|
|
|
|
if (bw >= 0)
|
|
|
|
bw = -EIO;
|
|
|
|
return bw;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* do_lo_send_direct_write - helper for writing data to a loop device
|
|
|
|
*
|
2011-10-17 04:57:20 -06:00
|
|
|
* This is the fast, non-transforming version that does not need double
|
|
|
|
* buffering.
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
|
|
|
static int do_lo_send_direct_write(struct loop_device *lo,
|
2007-10-08 10:10:13 -06:00
|
|
|
struct bio_vec *bvec, loff_t pos, struct page *page)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
ssize_t bw = __do_lo_send_write(lo->lo_backing_file,
|
2006-10-10 15:45:07 -06:00
|
|
|
kmap(bvec->bv_page) + bvec->bv_offset,
|
2005-04-16 16:20:36 -06:00
|
|
|
bvec->bv_len, pos);
|
|
|
|
kunmap(bvec->bv_page);
|
|
|
|
cond_resched();
|
|
|
|
return bw;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* do_lo_send_write - helper for writing data to a loop device
|
|
|
|
*
|
2011-10-17 04:57:20 -06:00
|
|
|
* This is the slow, transforming version that needs to double buffer the
|
|
|
|
* data as it cannot do the transformations in place without having direct
|
|
|
|
* access to the destination pages of the backing file.
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
|
|
|
static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,
|
2007-10-08 10:10:13 -06:00
|
|
|
loff_t pos, struct page *page)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,
|
|
|
|
bvec->bv_offset, bvec->bv_len, pos >> 9);
|
|
|
|
if (likely(!ret))
|
|
|
|
return __do_lo_send_write(lo->lo_backing_file,
|
2006-10-10 15:45:07 -06:00
|
|
|
page_address(page), bvec->bv_len,
|
2005-04-16 16:20:36 -06:00
|
|
|
pos);
|
drivers/block/loop.c: ratelimit error messages
Metric tons of high speed spew is not helpful when things go pear shaped.
systemd lost its mind, forgot how to stop services it insists on being
sole manager of, massive printk() flood ensued, box eventually died.
[16206.684000] loop: Write error at byte offset 11412291584, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 13155434496, length 4096.
[16206.684000] loop: Write error at byte offset 13155438592, length 4096.
[16206.684000] loop: Write error at byte offset 13155442688, length 4096.
[16206.684000] loop: Write error at byte offset 13960736768, length 4096.
[16206.684000] loop: Write error at byte offset 14229172224, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 14766043136, length 4096.
[16206.684000] loop: Write error at byte offset 15034478592, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
Signed-off-by: Mike Galbraith <bitbucket@online.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-08 14:43:52 -06:00
|
|
|
printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, "
|
2005-04-16 16:20:36 -06:00
|
|
|
"length %i.\n", (unsigned long long)pos, bvec->bv_len);
|
|
|
|
if (ret > 0)
|
|
|
|
ret = -EIO;
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
static int lo_send(struct loop_device *lo, struct request *rq, loff_t pos)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2007-10-08 10:10:13 -06:00
|
|
|
int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
|
2005-04-16 16:20:36 -06:00
|
|
|
struct page *page);
|
2013-11-23 18:19:00 -07:00
|
|
|
struct bio_vec bvec;
|
2014-12-31 06:22:58 -07:00
|
|
|
struct req_iterator iter;
|
2005-04-16 16:20:36 -06:00
|
|
|
struct page *page = NULL;
|
2013-11-23 18:19:00 -07:00
|
|
|
int ret = 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2011-10-17 04:57:20 -06:00
|
|
|
if (lo->transfer != transfer_none) {
|
|
|
|
page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
|
|
|
|
if (unlikely(!page))
|
|
|
|
goto fail;
|
|
|
|
kmap(page);
|
|
|
|
do_lo_send = do_lo_send_write;
|
|
|
|
} else {
|
2005-04-16 16:20:36 -06:00
|
|
|
do_lo_send = do_lo_send_direct_write;
|
|
|
|
}
|
2011-10-17 04:57:20 -06:00
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
rq_for_each_segment(bvec, rq, iter) {
|
2013-11-23 18:19:00 -07:00
|
|
|
ret = do_lo_send(lo, &bvec, pos, page);
|
2005-04-16 16:20:36 -06:00
|
|
|
if (ret < 0)
|
|
|
|
break;
|
2013-11-23 18:19:00 -07:00
|
|
|
pos += bvec.bv_len;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
if (page) {
|
|
|
|
kunmap(page);
|
|
|
|
__free_page(page);
|
|
|
|
}
|
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
fail:
|
drivers/block/loop.c: ratelimit error messages
Metric tons of high speed spew is not helpful when things go pear shaped.
systemd lost its mind, forgot how to stop services it insists on being
sole manager of, massive printk() flood ensued, box eventually died.
[16206.684000] loop: Write error at byte offset 11412291584, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 13155434496, length 4096.
[16206.684000] loop: Write error at byte offset 13155438592, length 4096.
[16206.684000] loop: Write error at byte offset 13155442688, length 4096.
[16206.684000] loop: Write error at byte offset 13960736768, length 4096.
[16206.684000] loop: Write error at byte offset 14229172224, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 14766043136, length 4096.
[16206.684000] loop: Write error at byte offset 15034478592, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
Signed-off-by: Mike Galbraith <bitbucket@online.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-08 14:43:52 -06:00
|
|
|
printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n");
|
2005-04-16 16:20:36 -06:00
|
|
|
ret = -ENOMEM;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
struct lo_read_data {
|
|
|
|
struct loop_device *lo;
|
|
|
|
struct page *page;
|
|
|
|
unsigned offset;
|
|
|
|
int bsize;
|
|
|
|
};
|
|
|
|
|
|
|
|
static int
|
2007-06-12 13:20:37 -06:00
|
|
|
lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
|
|
|
|
struct splice_desc *sd)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2007-06-12 13:20:37 -06:00
|
|
|
struct lo_read_data *p = sd->u.data;
|
2005-04-16 16:20:36 -06:00
|
|
|
struct loop_device *lo = p->lo;
|
2007-06-12 13:20:37 -06:00
|
|
|
struct page *page = buf->page;
|
2005-04-16 16:20:36 -06:00
|
|
|
sector_t IV;
|
2010-12-20 01:15:19 -07:00
|
|
|
int size;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2007-06-12 13:20:37 -06:00
|
|
|
IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +
|
|
|
|
(buf->offset >> 9);
|
|
|
|
size = sd->len;
|
|
|
|
if (size > p->bsize)
|
|
|
|
size = p->bsize;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2007-06-12 13:20:37 -06:00
|
|
|
if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {
|
drivers/block/loop.c: ratelimit error messages
Metric tons of high speed spew is not helpful when things go pear shaped.
systemd lost its mind, forgot how to stop services it insists on being
sole manager of, massive printk() flood ensued, box eventually died.
[16206.684000] loop: Write error at byte offset 11412291584, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 13155434496, length 4096.
[16206.684000] loop: Write error at byte offset 13155438592, length 4096.
[16206.684000] loop: Write error at byte offset 13155442688, length 4096.
[16206.684000] loop: Write error at byte offset 13960736768, length 4096.
[16206.684000] loop: Write error at byte offset 14229172224, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
[16206.684000] loop: Write error at byte offset 14766043136, length 4096.
[16206.684000] loop: Write error at byte offset 15034478592, length 4096.
[16206.684000] systemd-journald[1758]: /dev/kmsg buffer overrun, some messages lost.
Signed-off-by: Mike Galbraith <bitbucket@online.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-08 14:43:52 -06:00
|
|
|
printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n",
|
2005-04-16 16:20:36 -06:00
|
|
|
page->index);
|
2007-06-12 13:20:37 -06:00
|
|
|
size = -EINVAL;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
flush_dcache_page(p->page);
|
|
|
|
|
2007-06-12 13:20:37 -06:00
|
|
|
if (size > 0)
|
|
|
|
p->offset += size;
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
return size;
|
|
|
|
}
|
|
|
|
|
2007-06-12 13:20:37 -06:00
|
|
|
static int
|
|
|
|
lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)
|
|
|
|
{
|
|
|
|
return __splice_from_pipe(pipe, sd, lo_splice_actor);
|
|
|
|
}
|
|
|
|
|
2012-02-08 14:07:19 -07:00
|
|
|
static ssize_t
|
2005-04-16 16:20:36 -06:00
|
|
|
do_lo_receive(struct loop_device *lo,
|
|
|
|
struct bio_vec *bvec, int bsize, loff_t pos)
|
|
|
|
{
|
|
|
|
struct lo_read_data cookie;
|
2007-06-12 13:20:37 -06:00
|
|
|
struct splice_desc sd;
|
2005-04-16 16:20:36 -06:00
|
|
|
struct file *file;
|
2012-02-08 14:07:19 -07:00
|
|
|
ssize_t retval;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
cookie.lo = lo;
|
|
|
|
cookie.page = bvec->bv_page;
|
|
|
|
cookie.offset = bvec->bv_offset;
|
|
|
|
cookie.bsize = bsize;
|
2007-06-12 13:20:37 -06:00
|
|
|
|
|
|
|
sd.len = 0;
|
|
|
|
sd.total_len = bvec->bv_len;
|
|
|
|
sd.flags = 0;
|
|
|
|
sd.pos = pos;
|
|
|
|
sd.u.data = &cookie;
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
file = lo->lo_backing_file;
|
2007-06-12 13:20:37 -06:00
|
|
|
retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);
|
|
|
|
|
2012-02-08 14:07:19 -07:00
|
|
|
return retval;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
2014-12-31 06:22:58 -07:00
|
|
|
lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2013-11-23 18:19:00 -07:00
|
|
|
struct bio_vec bvec;
|
2014-12-31 06:22:58 -07:00
|
|
|
struct req_iterator iter;
|
2012-02-08 14:07:19 -07:00
|
|
|
ssize_t s;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
rq_for_each_segment(bvec, rq, iter) {
|
2013-11-23 18:19:00 -07:00
|
|
|
s = do_lo_receive(lo, &bvec, bsize, pos);
|
2012-02-08 14:07:19 -07:00
|
|
|
if (s < 0)
|
|
|
|
return s;
|
|
|
|
|
2013-11-23 18:19:00 -07:00
|
|
|
if (s != bvec.bv_len) {
|
2014-12-31 06:22:58 -07:00
|
|
|
struct bio *bio;
|
|
|
|
|
|
|
|
__rq_for_each_bio(bio, rq)
|
|
|
|
zero_fill_bio(bio);
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
2012-02-08 14:07:19 -07:00
|
|
|
}
|
2013-11-23 18:19:00 -07:00
|
|
|
pos += bvec.bv_len;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
2012-02-08 14:07:19 -07:00
|
|
|
return 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2014-12-31 06:22:59 -07:00
|
|
|
static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* We use punch hole to reclaim the free space used by the
|
|
|
|
* image a.k.a. discard. However we do not support discard if
|
|
|
|
* encryption is enabled, because it may give an attacker
|
|
|
|
* useful information.
|
|
|
|
*/
|
|
|
|
struct file *file = lo->lo_backing_file;
|
|
|
|
int mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if ((!file->f_op->fallocate) || lo->lo_encrypt_key_size) {
|
|
|
|
ret = -EOPNOTSUPP;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
|
|
|
|
if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
|
|
|
|
ret = -EIO;
|
|
|
|
out:
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int lo_req_flush(struct loop_device *lo, struct request *rq)
|
|
|
|
{
|
|
|
|
struct file *file = lo->lo_backing_file;
|
|
|
|
int ret = vfs_fsync(file, 0);
|
|
|
|
if (unlikely(ret && ret != -EINVAL))
|
|
|
|
ret = -EIO;
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
static int do_req_filebacked(struct loop_device *lo, struct request *rq)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
loff_t pos;
|
|
|
|
int ret;
|
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
|
2009-03-24 05:29:54 -06:00
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
if (rq->cmd_flags & REQ_WRITE) {
|
2014-12-31 06:22:59 -07:00
|
|
|
if (rq->cmd_flags & REQ_FLUSH)
|
|
|
|
ret = lo_req_flush(lo, rq);
|
2014-12-31 06:23:00 -07:00
|
|
|
else if (rq->cmd_flags & REQ_DISCARD)
|
2014-12-31 06:22:59 -07:00
|
|
|
ret = lo_discard(lo, rq, pos);
|
2014-12-31 06:23:00 -07:00
|
|
|
else
|
|
|
|
ret = lo_send(lo, rq, pos);
|
2009-03-24 05:29:54 -06:00
|
|
|
} else
|
2014-12-31 06:22:58 -07:00
|
|
|
ret = lo_receive(lo, rq, lo->lo_blocksize, pos);
|
2009-03-24 05:29:54 -06:00
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
struct switch_request {
|
|
|
|
struct file *file;
|
|
|
|
struct completion wait;
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
* Do the actual switch; called from the BIO completion routine
|
2005-04-16 16:20:36 -06:00
|
|
|
*/
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
static void do_loop_switch(struct loop_device *lo, struct switch_request *p)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
struct file *file = p->file;
|
|
|
|
struct file *old_file = lo->lo_backing_file;
|
|
|
|
struct address_space *mapping;
|
2005-06-23 01:09:06 -06:00
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
/* if no new file, only flush of queued bios requested */
|
|
|
|
if (!file)
|
|
|
|
return;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
mapping = file->f_mapping;
|
|
|
|
mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
|
|
|
|
lo->lo_backing_file = file;
|
|
|
|
lo->lo_blocksize = S_ISBLK(mapping->host->i_mode) ?
|
|
|
|
mapping->host->i_bdev->bd_block_size : PAGE_SIZE;
|
|
|
|
lo->old_gfp_mask = mapping_gfp_mask(mapping);
|
|
|
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* loop_switch performs the hard work of switching a backing store.
|
|
|
|
* First it needs to flush existing IO, it does this by sending a magic
|
|
|
|
* BIO down the pipe. The completion of this BIO does the actual switch.
|
|
|
|
*/
|
|
|
|
static int loop_switch(struct loop_device *lo, struct file *file)
|
|
|
|
{
|
|
|
|
struct switch_request w;
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
w.file = file;
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
|
|
|
|
/* freeze queue and wait for completion of scheduled requests */
|
|
|
|
blk_mq_freeze_queue(lo->lo_queue);
|
|
|
|
|
|
|
|
/* do the switch action */
|
|
|
|
do_loop_switch(lo, &w);
|
|
|
|
|
|
|
|
/* unfreeze */
|
|
|
|
blk_mq_unfreeze_queue(lo->lo_queue);
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2008-12-12 06:48:27 -07:00
|
|
|
/*
|
|
|
|
* Helper to flush the IOs in loop, but keeping loop thread running
|
|
|
|
*/
|
|
|
|
static int loop_flush(struct loop_device *lo)
|
|
|
|
{
|
|
|
|
return loop_switch(lo, NULL);
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
/*
|
|
|
|
* loop_change_fd switched the backing store of a loopback device to
|
|
|
|
* a new file. This is useful for operating system installers to free up
|
|
|
|
* the original file and in High Availability environments to switch to
|
|
|
|
* an alternative location for the content in case of server meltdown.
|
|
|
|
* This can only work if the loop device is used read-only, and if the
|
|
|
|
* new backing store is the same size and type as the old backing store.
|
|
|
|
*/
|
2008-03-02 07:29:48 -07:00
|
|
|
static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
|
|
|
|
unsigned int arg)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
struct file *file, *old_file;
|
|
|
|
struct inode *inode;
|
|
|
|
int error;
|
|
|
|
|
|
|
|
error = -ENXIO;
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
/* the loop device has to be read-only */
|
|
|
|
error = -EINVAL;
|
|
|
|
if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
error = -EBADF;
|
|
|
|
file = fget(arg);
|
|
|
|
if (!file)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
inode = file->f_mapping->host;
|
|
|
|
old_file = lo->lo_backing_file;
|
|
|
|
|
|
|
|
error = -EINVAL;
|
|
|
|
|
|
|
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
|
|
|
|
goto out_putf;
|
|
|
|
|
|
|
|
/* size of the new backing store needs to be the same */
|
|
|
|
if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
|
|
|
|
goto out_putf;
|
|
|
|
|
|
|
|
/* and ... switch */
|
|
|
|
error = loop_switch(lo, file);
|
|
|
|
if (error)
|
|
|
|
goto out_putf;
|
|
|
|
|
|
|
|
fput(old_file);
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_putf:
|
|
|
|
fput(file);
|
|
|
|
out:
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int is_loop_device(struct file *file)
|
|
|
|
{
|
|
|
|
struct inode *i = file->f_mapping->host;
|
|
|
|
|
|
|
|
return i && S_ISBLK(i->i_mode) && MAJOR(i->i_rdev) == LOOP_MAJOR;
|
|
|
|
}
|
|
|
|
|
2010-08-23 07:16:00 -06:00
|
|
|
/* loop sysfs attributes */
|
|
|
|
|
|
|
|
static ssize_t loop_attr_show(struct device *dev, char *page,
|
|
|
|
ssize_t (*callback)(struct loop_device *, char *))
|
|
|
|
{
|
2011-07-31 14:08:04 -06:00
|
|
|
struct gendisk *disk = dev_to_disk(dev);
|
|
|
|
struct loop_device *lo = disk->private_data;
|
2010-08-23 07:16:00 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
return callback(lo, page);
|
2010-08-23 07:16:00 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
#define LOOP_ATTR_RO(_name) \
|
|
|
|
static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \
|
|
|
|
static ssize_t loop_attr_do_show_##_name(struct device *d, \
|
|
|
|
struct device_attribute *attr, char *b) \
|
|
|
|
{ \
|
|
|
|
return loop_attr_show(d, b, loop_attr_##_name##_show); \
|
|
|
|
} \
|
|
|
|
static struct device_attribute loop_attr_##_name = \
|
|
|
|
__ATTR(_name, S_IRUGO, loop_attr_do_show_##_name, NULL);
|
|
|
|
|
|
|
|
static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
|
|
|
|
{
|
|
|
|
ssize_t ret;
|
|
|
|
char *p = NULL;
|
|
|
|
|
2011-07-31 14:21:35 -06:00
|
|
|
spin_lock_irq(&lo->lo_lock);
|
2010-08-23 07:16:00 -06:00
|
|
|
if (lo->lo_backing_file)
|
|
|
|
p = d_path(&lo->lo_backing_file->f_path, buf, PAGE_SIZE - 1);
|
2011-07-31 14:21:35 -06:00
|
|
|
spin_unlock_irq(&lo->lo_lock);
|
2010-08-23 07:16:00 -06:00
|
|
|
|
|
|
|
if (IS_ERR_OR_NULL(p))
|
|
|
|
ret = PTR_ERR(p);
|
|
|
|
else {
|
|
|
|
ret = strlen(p);
|
|
|
|
memmove(buf, p, ret);
|
|
|
|
buf[ret++] = '\n';
|
|
|
|
buf[ret] = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
|
|
|
|
{
|
|
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
|
|
|
|
{
|
|
|
|
return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf)
|
|
|
|
{
|
|
|
|
int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR);
|
|
|
|
|
|
|
|
return sprintf(buf, "%s\n", autoclear ? "1" : "0");
|
|
|
|
}
|
|
|
|
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
|
|
|
|
{
|
|
|
|
int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
|
|
|
|
|
|
|
|
return sprintf(buf, "%s\n", partscan ? "1" : "0");
|
|
|
|
}
|
|
|
|
|
2010-08-23 07:16:00 -06:00
|
|
|
LOOP_ATTR_RO(backing_file);
|
|
|
|
LOOP_ATTR_RO(offset);
|
|
|
|
LOOP_ATTR_RO(sizelimit);
|
|
|
|
LOOP_ATTR_RO(autoclear);
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
LOOP_ATTR_RO(partscan);
|
2010-08-23 07:16:00 -06:00
|
|
|
|
|
|
|
static struct attribute *loop_attrs[] = {
|
|
|
|
&loop_attr_backing_file.attr,
|
|
|
|
&loop_attr_offset.attr,
|
|
|
|
&loop_attr_sizelimit.attr,
|
|
|
|
&loop_attr_autoclear.attr,
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
&loop_attr_partscan.attr,
|
2010-08-23 07:16:00 -06:00
|
|
|
NULL,
|
|
|
|
};
|
|
|
|
|
|
|
|
static struct attribute_group loop_attribute_group = {
|
|
|
|
.name = "loop",
|
|
|
|
.attrs= loop_attrs,
|
|
|
|
};
|
|
|
|
|
|
|
|
static int loop_sysfs_init(struct loop_device *lo)
|
|
|
|
{
|
|
|
|
return sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
|
|
&loop_attribute_group);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void loop_sysfs_exit(struct loop_device *lo)
|
|
|
|
{
|
|
|
|
sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
|
|
|
|
&loop_attribute_group);
|
|
|
|
}
|
|
|
|
|
2011-08-19 06:50:46 -06:00
|
|
|
static void loop_config_discard(struct loop_device *lo)
|
|
|
|
{
|
|
|
|
struct file *file = lo->lo_backing_file;
|
|
|
|
struct inode *inode = file->f_mapping->host;
|
|
|
|
struct request_queue *q = lo->lo_queue;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We use punch hole to reclaim the free space used by the
|
2014-01-21 15:39:24 -07:00
|
|
|
* image a.k.a. discard. However we do not support discard if
|
2011-08-19 06:50:46 -06:00
|
|
|
* encryption is enabled, because it may give an attacker
|
|
|
|
* useful information.
|
|
|
|
*/
|
|
|
|
if ((!file->f_op->fallocate) ||
|
|
|
|
lo->lo_encrypt_key_size) {
|
|
|
|
q->limits.discard_granularity = 0;
|
|
|
|
q->limits.discard_alignment = 0;
|
|
|
|
q->limits.max_discard_sectors = 0;
|
|
|
|
q->limits.discard_zeroes_data = 0;
|
|
|
|
queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
q->limits.discard_granularity = inode->i_sb->s_blocksize;
|
2011-12-02 06:47:03 -07:00
|
|
|
q->limits.discard_alignment = 0;
|
2011-08-19 06:50:46 -06:00
|
|
|
q->limits.max_discard_sectors = UINT_MAX >> 9;
|
|
|
|
q->limits.discard_zeroes_data = 1;
|
|
|
|
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
|
|
|
|
}
|
|
|
|
|
2008-03-02 07:29:48 -07:00
|
|
|
static int loop_set_fd(struct loop_device *lo, fmode_t mode,
|
2005-04-16 16:20:36 -06:00
|
|
|
struct block_device *bdev, unsigned int arg)
|
|
|
|
{
|
|
|
|
struct file *file, *f;
|
|
|
|
struct inode *inode;
|
|
|
|
struct address_space *mapping;
|
|
|
|
unsigned lo_blocksize;
|
|
|
|
int lo_flags = 0;
|
|
|
|
int error;
|
|
|
|
loff_t size;
|
|
|
|
|
|
|
|
/* This is safe, since we have a reference from open(). */
|
|
|
|
__module_get(THIS_MODULE);
|
|
|
|
|
|
|
|
error = -EBADF;
|
|
|
|
file = fget(arg);
|
|
|
|
if (!file)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
error = -EBUSY;
|
|
|
|
if (lo->lo_state != Lo_unbound)
|
|
|
|
goto out_putf;
|
|
|
|
|
|
|
|
/* Avoid recursion */
|
|
|
|
f = file;
|
|
|
|
while (is_loop_device(f)) {
|
|
|
|
struct loop_device *l;
|
|
|
|
|
2008-03-02 07:29:48 -07:00
|
|
|
if (f->f_mapping->host->i_bdev == bdev)
|
2005-04-16 16:20:36 -06:00
|
|
|
goto out_putf;
|
|
|
|
|
|
|
|
l = f->f_mapping->host->i_bdev->bd_disk->private_data;
|
|
|
|
if (l->lo_state == Lo_unbound) {
|
|
|
|
error = -EINVAL;
|
|
|
|
goto out_putf;
|
|
|
|
}
|
|
|
|
f = l->lo_backing_file;
|
|
|
|
}
|
|
|
|
|
|
|
|
mapping = file->f_mapping;
|
|
|
|
inode = mapping->host;
|
|
|
|
|
|
|
|
error = -EINVAL;
|
2011-10-17 04:57:20 -06:00
|
|
|
if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
|
|
|
|
goto out_putf;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2011-10-17 04:57:20 -06:00
|
|
|
if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
|
|
|
|
!file->f_op->write)
|
|
|
|
lo_flags |= LO_FLAGS_READ_ONLY;
|
2006-09-27 02:50:49 -06:00
|
|
|
|
2011-10-17 04:57:20 -06:00
|
|
|
lo_blocksize = S_ISBLK(inode->i_mode) ?
|
|
|
|
inode->i_bdev->bd_block_size : PAGE_SIZE;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2011-10-17 04:57:20 -06:00
|
|
|
error = -EFBIG;
|
2005-04-16 16:20:36 -06:00
|
|
|
size = get_loop_size(lo, file);
|
2011-10-17 04:57:20 -06:00
|
|
|
if ((loff_t)(sector_t)size != size)
|
2005-04-16 16:20:36 -06:00
|
|
|
goto out_putf;
|
|
|
|
|
2011-10-17 04:57:20 -06:00
|
|
|
error = 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
|
|
|
|
|
|
|
|
lo->lo_blocksize = lo_blocksize;
|
|
|
|
lo->lo_device = bdev;
|
|
|
|
lo->lo_flags = lo_flags;
|
|
|
|
lo->lo_backing_file = file;
|
2006-06-23 03:06:08 -06:00
|
|
|
lo->transfer = transfer_none;
|
2005-04-16 16:20:36 -06:00
|
|
|
lo->ioctl = NULL;
|
|
|
|
lo->lo_sizelimit = 0;
|
|
|
|
lo->old_gfp_mask = mapping_gfp_mask(mapping);
|
|
|
|
mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
|
|
|
|
|
2009-03-24 05:29:54 -06:00
|
|
|
if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
|
2010-09-03 03:56:16 -06:00
|
|
|
blk_queue_flush(lo->lo_queue, REQ_FLUSH);
|
2009-03-24 05:29:54 -06:00
|
|
|
|
2007-05-08 01:28:20 -06:00
|
|
|
set_capacity(lo->lo_disk, size);
|
2005-04-16 16:20:36 -06:00
|
|
|
bd_set_size(bdev, size << 9);
|
2010-08-23 07:16:00 -06:00
|
|
|
loop_sysfs_init(lo);
|
2010-05-03 06:08:59 -06:00
|
|
|
/* let user-space know about the new size */
|
|
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
set_blocksize(bdev, lo_blocksize);
|
|
|
|
|
2006-09-29 02:59:11 -06:00
|
|
|
lo->lo_state = Lo_bound;
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
if (part_shift)
|
|
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN)
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
2013-04-01 10:47:56 -06:00
|
|
|
|
|
|
|
/* Grab the block_device to prevent its destruction after we
|
|
|
|
* put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev).
|
|
|
|
*/
|
|
|
|
bdgrab(bdev);
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_putf:
|
|
|
|
fput(file);
|
|
|
|
out:
|
|
|
|
/* This is safe: open() is still holding a reference. */
|
|
|
|
module_put(THIS_MODULE);
|
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_release_xfer(struct loop_device *lo)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
struct loop_func_table *xfer = lo->lo_encryption;
|
|
|
|
|
|
|
|
if (xfer) {
|
|
|
|
if (xfer->release)
|
|
|
|
err = xfer->release(lo);
|
|
|
|
lo->transfer = NULL;
|
|
|
|
lo->lo_encryption = NULL;
|
|
|
|
module_put(xfer->owner);
|
|
|
|
}
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
|
|
|
|
const struct loop_info64 *i)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (xfer) {
|
|
|
|
struct module *owner = xfer->owner;
|
|
|
|
|
|
|
|
if (!try_module_get(owner))
|
|
|
|
return -EINVAL;
|
|
|
|
if (xfer->init)
|
|
|
|
err = xfer->init(lo, i);
|
|
|
|
if (err)
|
|
|
|
module_put(owner);
|
|
|
|
else
|
|
|
|
lo->lo_encryption = xfer;
|
|
|
|
}
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2011-09-21 02:02:13 -06:00
|
|
|
static int loop_clr_fd(struct loop_device *lo)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
|
|
|
struct file *filp = lo->lo_backing_file;
|
2005-10-21 01:22:34 -06:00
|
|
|
gfp_t gfp = lo->old_gfp_mask;
|
2011-09-21 02:02:13 -06:00
|
|
|
struct block_device *bdev = lo->lo_device;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
|
|
return -ENXIO;
|
|
|
|
|
loop: Make explicit loop device destruction lazy
xfstests has always had random failures of tests due to loop devices
failing to be torn down and hence leaving filesytems that cannot be
unmounted. This causes test runs to immediately stop.
Over the past 6 or 7 years we've added hacks like explicit unmount
-d commands for loop mounts, losetup -d after unmount -d fails, etc,
but still the problems persist. Recently, the frequency of loop
related failures increased again to the point that xfstests 259 will
reliably fail with a stray loop device that was not torn down.
That is despite the fact the test is above as simple as it gets -
loop 5 or 6 times running mkfs.xfs with different paramters:
lofile=$(losetup -f)
losetup $lofile "$testfile"
"$MKFS_XFS_PROG" -b size=512 $lofile >/dev/null || echo "mkfs failed!"
sync
losetup -d $lofile
And losteup -d $lofile is failing with EBUSY on 1-3 of these loops
every time the test is run.
Turns out that blkid is running simultaneously with losetup -d, and
so it sees an elevated reference count and returns EBUSY. But why
is blkid running? It's obvious, isn't it? udev has decided to try
and find out what is on the block device as a result of a creation
notification. And it is racing with mkfs, so might still be scanning
the device when mkfs finishes and we try to tear it down.
So, make losetup -d force autoremove behaviour. That is, when the
last reference goes away, tear down the device. xfstests wants it
*gone*, not causing random teardown failures when we know that all
the operations the tests have specifically run on the device have
completed and are no longer referencing the loop device.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-09-28 02:42:23 -06:00
|
|
|
/*
|
|
|
|
* If we've explicitly asked to tear down the loop device,
|
|
|
|
* and it has an elevated reference count, set it for auto-teardown when
|
|
|
|
* the last reference goes away. This stops $!~#$@ udev from
|
|
|
|
* preventing teardown because it decided that it needs to run blkid on
|
|
|
|
* the loopback device whenever they appear. xfstests is notorious for
|
|
|
|
* failing tests because blkid via udev races with a losetup
|
|
|
|
* <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
|
|
|
|
* command to fail with EBUSY.
|
|
|
|
*/
|
|
|
|
if (lo->lo_refcnt > 1) {
|
|
|
|
lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
return 0;
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
if (filp == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
|
|
lo->lo_state = Lo_rundown;
|
|
|
|
lo->lo_backing_file = NULL;
|
2011-07-31 14:21:35 -06:00
|
|
|
spin_unlock_irq(&lo->lo_lock);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
loop_release_xfer(lo);
|
|
|
|
lo->transfer = NULL;
|
|
|
|
lo->ioctl = NULL;
|
|
|
|
lo->lo_device = NULL;
|
|
|
|
lo->lo_encryption = NULL;
|
|
|
|
lo->lo_offset = 0;
|
|
|
|
lo->lo_sizelimit = 0;
|
|
|
|
lo->lo_encrypt_key_size = 0;
|
|
|
|
memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
|
|
|
|
memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
|
|
|
|
memset(lo->lo_file_name, 0, LO_NAME_SIZE);
|
2013-04-01 10:47:56 -06:00
|
|
|
if (bdev) {
|
|
|
|
bdput(bdev);
|
2008-03-02 07:29:48 -07:00
|
|
|
invalidate_bdev(bdev);
|
2013-04-01 10:47:56 -06:00
|
|
|
}
|
2007-05-08 01:28:20 -06:00
|
|
|
set_capacity(lo->lo_disk, 0);
|
2010-10-27 19:51:30 -06:00
|
|
|
loop_sysfs_exit(lo);
|
2010-05-03 06:08:59 -06:00
|
|
|
if (bdev) {
|
2008-03-02 07:29:48 -07:00
|
|
|
bd_set_size(bdev, 0);
|
2010-05-03 06:08:59 -06:00
|
|
|
/* let user-space know about this change */
|
|
|
|
kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
mapping_set_gfp_mask(filp->f_mapping, gfp);
|
|
|
|
lo->lo_state = Lo_unbound;
|
|
|
|
/* This is safe: open() is still holding a reference. */
|
|
|
|
module_put(THIS_MODULE);
|
2013-04-08 02:12:11 -06:00
|
|
|
if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
|
|
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
lo->lo_flags = 0;
|
|
|
|
if (!part_shift)
|
|
|
|
lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
|
loop: fix circular locking in loop_clr_fd()
With CONFIG_PROVE_LOCKING enabled
$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0
$ losetup -d /dev/loop1
$ losetup -d /dev/loop0
triggers a [ INFO: possible circular locking dependency detected ]
I think this warning is a false positive.
Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.
So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.
@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock(&lo->lo_ctl_mutex);
+ mutex_lock_nested(&lo->lo_ctl_mutex, 1);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.
Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.
If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 05:33:41 -06:00
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
/*
|
|
|
|
* Need not hold lo_ctl_mutex to fput backing file.
|
|
|
|
* Calling fput holding lo_ctl_mutex triggers a circular
|
|
|
|
* lock dependency possibility warning as fput can take
|
|
|
|
* bd_mutex which is usually taken before lo_ctl_mutex.
|
|
|
|
*/
|
|
|
|
fput(filp);
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
|
|
|
|
{
|
|
|
|
int err;
|
|
|
|
struct loop_func_table *xfer;
|
2012-02-11 12:23:51 -07:00
|
|
|
kuid_t uid = current_uid();
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2008-11-13 16:38:41 -07:00
|
|
|
if (lo->lo_encrypt_key_size &&
|
2012-02-11 12:23:51 -07:00
|
|
|
!uid_eq(lo->lo_key_owner, uid) &&
|
2005-04-16 16:20:36 -06:00
|
|
|
!capable(CAP_SYS_ADMIN))
|
|
|
|
return -EPERM;
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
|
|
return -ENXIO;
|
|
|
|
if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
err = loop_release_xfer(lo);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
if (info->lo_encrypt_type) {
|
|
|
|
unsigned int type = info->lo_encrypt_type;
|
|
|
|
|
|
|
|
if (type >= MAX_LO_CRYPT)
|
|
|
|
return -EINVAL;
|
|
|
|
xfer = xfer_funcs[type];
|
|
|
|
if (xfer == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
} else
|
|
|
|
xfer = NULL;
|
|
|
|
|
|
|
|
err = loop_init_xfer(lo, xfer, info);
|
|
|
|
if (err)
|
|
|
|
return err;
|
|
|
|
|
|
|
|
if (lo->lo_offset != info->lo_offset ||
|
2013-02-21 16:16:47 -07:00
|
|
|
lo->lo_sizelimit != info->lo_sizelimit)
|
2011-11-16 01:21:49 -07:00
|
|
|
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
|
2005-04-16 16:20:36 -06:00
|
|
|
return -EFBIG;
|
2013-02-21 16:16:46 -07:00
|
|
|
|
2011-08-19 06:50:46 -06:00
|
|
|
loop_config_discard(lo);
|
2005-04-16 16:20:36 -06:00
|
|
|
|
|
|
|
memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
|
|
|
|
memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
|
|
|
|
lo->lo_file_name[LO_NAME_SIZE-1] = 0;
|
|
|
|
lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
|
|
|
|
|
|
|
|
if (!xfer)
|
|
|
|
xfer = &none_funcs;
|
|
|
|
lo->transfer = xfer->transfer;
|
|
|
|
lo->ioctl = xfer->ioctl;
|
|
|
|
|
2008-02-06 02:36:27 -07:00
|
|
|
if ((lo->lo_flags & LO_FLAGS_AUTOCLEAR) !=
|
|
|
|
(info->lo_flags & LO_FLAGS_AUTOCLEAR))
|
|
|
|
lo->lo_flags ^= LO_FLAGS_AUTOCLEAR;
|
|
|
|
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
if ((info->lo_flags & LO_FLAGS_PARTSCAN) &&
|
|
|
|
!(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
|
|
|
|
lo->lo_flags |= LO_FLAGS_PARTSCAN;
|
|
|
|
lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
|
|
|
|
ioctl_by_bdev(lo->lo_device, BLKRRPART, 0);
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
|
|
|
|
lo->lo_init[0] = info->lo_init[0];
|
|
|
|
lo->lo_init[1] = info->lo_init[1];
|
|
|
|
if (info->lo_encrypt_key_size) {
|
|
|
|
memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
|
|
|
|
info->lo_encrypt_key_size);
|
2008-11-13 16:38:41 -07:00
|
|
|
lo->lo_key_owner = uid;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_get_status(struct loop_device *lo, struct loop_info64 *info)
|
|
|
|
{
|
|
|
|
struct file *file = lo->lo_backing_file;
|
|
|
|
struct kstat stat;
|
|
|
|
int error;
|
|
|
|
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
|
|
return -ENXIO;
|
2013-01-24 00:18:08 -07:00
|
|
|
error = vfs_getattr(&file->f_path, &stat);
|
2005-04-16 16:20:36 -06:00
|
|
|
if (error)
|
|
|
|
return error;
|
|
|
|
memset(info, 0, sizeof(*info));
|
|
|
|
info->lo_number = lo->lo_number;
|
|
|
|
info->lo_device = huge_encode_dev(stat.dev);
|
|
|
|
info->lo_inode = stat.ino;
|
|
|
|
info->lo_rdevice = huge_encode_dev(lo->lo_device ? stat.rdev : stat.dev);
|
|
|
|
info->lo_offset = lo->lo_offset;
|
|
|
|
info->lo_sizelimit = lo->lo_sizelimit;
|
|
|
|
info->lo_flags = lo->lo_flags;
|
|
|
|
memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
|
|
|
|
memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
|
|
|
|
info->lo_encrypt_type =
|
|
|
|
lo->lo_encryption ? lo->lo_encryption->number : 0;
|
|
|
|
if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
|
|
|
|
info->lo_encrypt_key_size = lo->lo_encrypt_key_size;
|
|
|
|
memcpy(info->lo_encrypt_key, lo->lo_encrypt_key,
|
|
|
|
lo->lo_encrypt_key_size);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void
|
|
|
|
loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
|
|
|
|
{
|
|
|
|
memset(info64, 0, sizeof(*info64));
|
|
|
|
info64->lo_number = info->lo_number;
|
|
|
|
info64->lo_device = info->lo_device;
|
|
|
|
info64->lo_inode = info->lo_inode;
|
|
|
|
info64->lo_rdevice = info->lo_rdevice;
|
|
|
|
info64->lo_offset = info->lo_offset;
|
|
|
|
info64->lo_sizelimit = 0;
|
|
|
|
info64->lo_encrypt_type = info->lo_encrypt_type;
|
|
|
|
info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
|
|
|
|
info64->lo_flags = info->lo_flags;
|
|
|
|
info64->lo_init[0] = info->lo_init[0];
|
|
|
|
info64->lo_init[1] = info->lo_init[1];
|
|
|
|
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
|
|
memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
|
|
|
|
else
|
|
|
|
memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
|
|
|
|
memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
|
|
|
|
{
|
|
|
|
memset(info, 0, sizeof(*info));
|
|
|
|
info->lo_number = info64->lo_number;
|
|
|
|
info->lo_device = info64->lo_device;
|
|
|
|
info->lo_inode = info64->lo_inode;
|
|
|
|
info->lo_rdevice = info64->lo_rdevice;
|
|
|
|
info->lo_offset = info64->lo_offset;
|
|
|
|
info->lo_encrypt_type = info64->lo_encrypt_type;
|
|
|
|
info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
|
|
|
|
info->lo_flags = info64->lo_flags;
|
|
|
|
info->lo_init[0] = info64->lo_init[0];
|
|
|
|
info->lo_init[1] = info64->lo_init[1];
|
|
|
|
if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
|
|
memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
|
|
|
|
else
|
|
|
|
memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
|
|
|
|
memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
|
|
|
|
|
|
|
|
/* error in case values were truncated */
|
|
|
|
if (info->lo_device != info64->lo_device ||
|
|
|
|
info->lo_rdevice != info64->lo_rdevice ||
|
|
|
|
info->lo_inode != info64->lo_inode ||
|
|
|
|
info->lo_offset != info64->lo_offset)
|
|
|
|
return -EOVERFLOW;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
|
|
|
|
{
|
|
|
|
struct loop_info info;
|
|
|
|
struct loop_info64 info64;
|
|
|
|
|
|
|
|
if (copy_from_user(&info, arg, sizeof (struct loop_info)))
|
|
|
|
return -EFAULT;
|
|
|
|
loop_info64_from_old(&info, &info64);
|
|
|
|
return loop_set_status(lo, &info64);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg)
|
|
|
|
{
|
|
|
|
struct loop_info64 info64;
|
|
|
|
|
|
|
|
if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
|
|
|
|
return -EFAULT;
|
|
|
|
return loop_set_status(lo, &info64);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
|
|
|
|
struct loop_info info;
|
|
|
|
struct loop_info64 info64;
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (!arg)
|
|
|
|
err = -EINVAL;
|
|
|
|
if (!err)
|
|
|
|
err = loop_get_status(lo, &info64);
|
|
|
|
if (!err)
|
|
|
|
err = loop_info64_to_old(&info64, &info);
|
|
|
|
if (!err && copy_to_user(arg, &info, sizeof(info)))
|
|
|
|
err = -EFAULT;
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
|
|
|
|
struct loop_info64 info64;
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (!arg)
|
|
|
|
err = -EINVAL;
|
|
|
|
if (!err)
|
|
|
|
err = loop_get_status(lo, &info64);
|
|
|
|
if (!err && copy_to_user(arg, &info64, sizeof(info64)))
|
|
|
|
err = -EFAULT;
|
|
|
|
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
loop: add ioctl to resize a loop device
Add the ability to 'resize' the loop device on the fly.
One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.
Test app:
#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <getopt.h>
char *me;
void usage(FILE *f)
{
fprintf(f, "%s [options] loop_dev [backend_file]\n"
"-s, --set new_size_in_bytes\n"
"\twhen backend_file is given, "
"it will be expanded too while keeping the original contents\n",
me);
}
struct option opts[] = {
{
.name = "set",
.has_arg = 1,
.flag = NULL,
.val = 's'
},
{
.name = "help",
.has_arg = 0,
.flag = NULL,
.val = 'h'
}
};
void err_size(char *name, __u64 old)
{
fprintf(stderr, "size must be larger than current %s (%llu)\n",
name, old);
}
int main(int argc, char *argv[])
{
int fd, err, c, i, bfd;
ssize_t ssz;
size_t sz;
__u64 old, new, append;
char a[BUFSIZ];
struct stat st;
FILE *out;
char *backend, *dev;
err = EINVAL;
out = stderr;
me = argv[0];
new = 0;
while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
switch (c) {
case 's':
errno = 0;
new = strtoull(optarg, NULL, 0);
if (errno) {
err = errno;
perror(argv[i]);
goto out;
}
break;
case 'h':
err = 0;
out = stdout;
goto err;
default:
perror(argv[i]);
goto err;
}
}
if (optind < argc)
dev = argv[optind++];
else
goto err;
fd = open(dev, O_RDONLY);
if (fd < 0) {
err = errno;
perror(dev);
goto out;
}
err = ioctl(fd, BLKGETSIZE64, &old);
if (err) {
err = errno;
perror("ioctl BLKGETSIZE64");
goto out;
}
if (!new) {
printf("%llu\n", old);
goto out;
}
if (new < old) {
err = EINVAL;
err_size(dev, old);
goto out;
}
if (optind < argc) {
backend = argv[optind++];
bfd = open(backend, O_WRONLY|O_APPEND);
if (bfd < 0) {
err = errno;
perror(backend);
goto out;
}
err = fstat(bfd, &st);
if (err) {
err = errno;
perror(backend);
goto out;
}
if (new < st.st_size) {
err = EINVAL;
err_size(backend, st.st_size);
goto out;
}
append = new - st.st_size;
sz = sizeof(a);
while (append > 0) {
if (append < sz)
sz = append;
ssz = write(bfd, a, sz);
if (ssz != sz) {
err = errno;
perror(backend);
goto out;
}
append -= sz;
}
err = fsync(bfd);
if (err) {
err = errno;
perror(backend);
goto out;
}
}
err = ioctl(fd, LOOP_SET_CAPACITY, new);
if (err) {
err = errno;
perror("ioctl LOOP_SET_CAPACITY");
}
goto out;
err:
usage(out);
out:
return err;
}
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Tomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31 16:23:43 -06:00
|
|
|
static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev)
|
|
|
|
{
|
|
|
|
if (unlikely(lo->lo_state != Lo_bound))
|
2013-02-21 16:16:47 -07:00
|
|
|
return -ENXIO;
|
loop: add ioctl to resize a loop device
Add the ability to 'resize' the loop device on the fly.
One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.
Test app:
#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <getopt.h>
char *me;
void usage(FILE *f)
{
fprintf(f, "%s [options] loop_dev [backend_file]\n"
"-s, --set new_size_in_bytes\n"
"\twhen backend_file is given, "
"it will be expanded too while keeping the original contents\n",
me);
}
struct option opts[] = {
{
.name = "set",
.has_arg = 1,
.flag = NULL,
.val = 's'
},
{
.name = "help",
.has_arg = 0,
.flag = NULL,
.val = 'h'
}
};
void err_size(char *name, __u64 old)
{
fprintf(stderr, "size must be larger than current %s (%llu)\n",
name, old);
}
int main(int argc, char *argv[])
{
int fd, err, c, i, bfd;
ssize_t ssz;
size_t sz;
__u64 old, new, append;
char a[BUFSIZ];
struct stat st;
FILE *out;
char *backend, *dev;
err = EINVAL;
out = stderr;
me = argv[0];
new = 0;
while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
switch (c) {
case 's':
errno = 0;
new = strtoull(optarg, NULL, 0);
if (errno) {
err = errno;
perror(argv[i]);
goto out;
}
break;
case 'h':
err = 0;
out = stdout;
goto err;
default:
perror(argv[i]);
goto err;
}
}
if (optind < argc)
dev = argv[optind++];
else
goto err;
fd = open(dev, O_RDONLY);
if (fd < 0) {
err = errno;
perror(dev);
goto out;
}
err = ioctl(fd, BLKGETSIZE64, &old);
if (err) {
err = errno;
perror("ioctl BLKGETSIZE64");
goto out;
}
if (!new) {
printf("%llu\n", old);
goto out;
}
if (new < old) {
err = EINVAL;
err_size(dev, old);
goto out;
}
if (optind < argc) {
backend = argv[optind++];
bfd = open(backend, O_WRONLY|O_APPEND);
if (bfd < 0) {
err = errno;
perror(backend);
goto out;
}
err = fstat(bfd, &st);
if (err) {
err = errno;
perror(backend);
goto out;
}
if (new < st.st_size) {
err = EINVAL;
err_size(backend, st.st_size);
goto out;
}
append = new - st.st_size;
sz = sizeof(a);
while (append > 0) {
if (append < sz)
sz = append;
ssz = write(bfd, a, sz);
if (ssz != sz) {
err = errno;
perror(backend);
goto out;
}
append -= sz;
}
err = fsync(bfd);
if (err) {
err = errno;
perror(backend);
goto out;
}
}
err = ioctl(fd, LOOP_SET_CAPACITY, new);
if (err) {
err = errno;
perror("ioctl LOOP_SET_CAPACITY");
}
goto out;
err:
usage(out);
out:
return err;
}
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Tomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31 16:23:43 -06:00
|
|
|
|
2013-02-21 16:16:47 -07:00
|
|
|
return figure_loop_size(lo, lo->lo_offset, lo->lo_sizelimit);
|
loop: add ioctl to resize a loop device
Add the ability to 'resize' the loop device on the fly.
One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.
Test app:
#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <getopt.h>
char *me;
void usage(FILE *f)
{
fprintf(f, "%s [options] loop_dev [backend_file]\n"
"-s, --set new_size_in_bytes\n"
"\twhen backend_file is given, "
"it will be expanded too while keeping the original contents\n",
me);
}
struct option opts[] = {
{
.name = "set",
.has_arg = 1,
.flag = NULL,
.val = 's'
},
{
.name = "help",
.has_arg = 0,
.flag = NULL,
.val = 'h'
}
};
void err_size(char *name, __u64 old)
{
fprintf(stderr, "size must be larger than current %s (%llu)\n",
name, old);
}
int main(int argc, char *argv[])
{
int fd, err, c, i, bfd;
ssize_t ssz;
size_t sz;
__u64 old, new, append;
char a[BUFSIZ];
struct stat st;
FILE *out;
char *backend, *dev;
err = EINVAL;
out = stderr;
me = argv[0];
new = 0;
while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
switch (c) {
case 's':
errno = 0;
new = strtoull(optarg, NULL, 0);
if (errno) {
err = errno;
perror(argv[i]);
goto out;
}
break;
case 'h':
err = 0;
out = stdout;
goto err;
default:
perror(argv[i]);
goto err;
}
}
if (optind < argc)
dev = argv[optind++];
else
goto err;
fd = open(dev, O_RDONLY);
if (fd < 0) {
err = errno;
perror(dev);
goto out;
}
err = ioctl(fd, BLKGETSIZE64, &old);
if (err) {
err = errno;
perror("ioctl BLKGETSIZE64");
goto out;
}
if (!new) {
printf("%llu\n", old);
goto out;
}
if (new < old) {
err = EINVAL;
err_size(dev, old);
goto out;
}
if (optind < argc) {
backend = argv[optind++];
bfd = open(backend, O_WRONLY|O_APPEND);
if (bfd < 0) {
err = errno;
perror(backend);
goto out;
}
err = fstat(bfd, &st);
if (err) {
err = errno;
perror(backend);
goto out;
}
if (new < st.st_size) {
err = EINVAL;
err_size(backend, st.st_size);
goto out;
}
append = new - st.st_size;
sz = sizeof(a);
while (append > 0) {
if (append < sz)
sz = append;
ssz = write(bfd, a, sz);
if (ssz != sz) {
err = errno;
perror(backend);
goto out;
}
append -= sz;
}
err = fsync(bfd);
if (err) {
err = errno;
perror(backend);
goto out;
}
}
err = ioctl(fd, LOOP_SET_CAPACITY, new);
if (err) {
err = errno;
perror("ioctl LOOP_SET_CAPACITY");
}
goto out;
err:
usage(out);
out:
return err;
}
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Tomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31 16:23:43 -06:00
|
|
|
}
|
|
|
|
|
2008-03-02 07:29:48 -07:00
|
|
|
static int lo_ioctl(struct block_device *bdev, fmode_t mode,
|
2005-04-16 16:20:36 -06:00
|
|
|
unsigned int cmd, unsigned long arg)
|
|
|
|
{
|
2008-03-02 07:29:48 -07:00
|
|
|
struct loop_device *lo = bdev->bd_disk->private_data;
|
2005-04-16 16:20:36 -06:00
|
|
|
int err;
|
|
|
|
|
loop: fix circular locking in loop_clr_fd()
With CONFIG_PROVE_LOCKING enabled
$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0
$ losetup -d /dev/loop1
$ losetup -d /dev/loop0
triggers a [ INFO: possible circular locking dependency detected ]
I think this warning is a false positive.
Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.
So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.
@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock(&lo->lo_ctl_mutex);
+ mutex_lock_nested(&lo->lo_ctl_mutex, 1);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.
Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.
If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 05:33:41 -06:00
|
|
|
mutex_lock_nested(&lo->lo_ctl_mutex, 1);
|
2005-04-16 16:20:36 -06:00
|
|
|
switch (cmd) {
|
|
|
|
case LOOP_SET_FD:
|
2008-03-02 07:29:48 -07:00
|
|
|
err = loop_set_fd(lo, mode, bdev, arg);
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
|
|
|
case LOOP_CHANGE_FD:
|
2008-03-02 07:29:48 -07:00
|
|
|
err = loop_change_fd(lo, bdev, arg);
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
|
|
|
case LOOP_CLR_FD:
|
loop: fix circular locking in loop_clr_fd()
With CONFIG_PROVE_LOCKING enabled
$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0
$ losetup -d /dev/loop1
$ losetup -d /dev/loop0
triggers a [ INFO: possible circular locking dependency detected ]
I think this warning is a false positive.
Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.
So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.
@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock(&lo->lo_ctl_mutex);
+ mutex_lock_nested(&lo->lo_ctl_mutex, 1);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.
Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.
If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 05:33:41 -06:00
|
|
|
/* loop_clr_fd would have unlocked lo_ctl_mutex on success */
|
2011-09-21 02:02:13 -06:00
|
|
|
err = loop_clr_fd(lo);
|
loop: fix circular locking in loop_clr_fd()
With CONFIG_PROVE_LOCKING enabled
$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0
$ losetup -d /dev/loop1
$ losetup -d /dev/loop0
triggers a [ INFO: possible circular locking dependency detected ]
I think this warning is a false positive.
Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.
So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.
@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock(&lo->lo_ctl_mutex);
+ mutex_lock_nested(&lo->lo_ctl_mutex, 1);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.
Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.
If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 05:33:41 -06:00
|
|
|
if (!err)
|
|
|
|
goto out_unlocked;
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
|
|
|
case LOOP_SET_STATUS:
|
2011-11-16 01:21:49 -07:00
|
|
|
err = -EPERM;
|
|
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
|
|
err = loop_set_status_old(lo,
|
|
|
|
(struct loop_info __user *)arg);
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
|
|
|
case LOOP_GET_STATUS:
|
|
|
|
err = loop_get_status_old(lo, (struct loop_info __user *) arg);
|
|
|
|
break;
|
|
|
|
case LOOP_SET_STATUS64:
|
2011-11-16 01:21:49 -07:00
|
|
|
err = -EPERM;
|
|
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
|
|
err = loop_set_status64(lo,
|
|
|
|
(struct loop_info64 __user *) arg);
|
2005-04-16 16:20:36 -06:00
|
|
|
break;
|
|
|
|
case LOOP_GET_STATUS64:
|
|
|
|
err = loop_get_status64(lo, (struct loop_info64 __user *) arg);
|
|
|
|
break;
|
loop: add ioctl to resize a loop device
Add the ability to 'resize' the loop device on the fly.
One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.
Test app:
#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <getopt.h>
char *me;
void usage(FILE *f)
{
fprintf(f, "%s [options] loop_dev [backend_file]\n"
"-s, --set new_size_in_bytes\n"
"\twhen backend_file is given, "
"it will be expanded too while keeping the original contents\n",
me);
}
struct option opts[] = {
{
.name = "set",
.has_arg = 1,
.flag = NULL,
.val = 's'
},
{
.name = "help",
.has_arg = 0,
.flag = NULL,
.val = 'h'
}
};
void err_size(char *name, __u64 old)
{
fprintf(stderr, "size must be larger than current %s (%llu)\n",
name, old);
}
int main(int argc, char *argv[])
{
int fd, err, c, i, bfd;
ssize_t ssz;
size_t sz;
__u64 old, new, append;
char a[BUFSIZ];
struct stat st;
FILE *out;
char *backend, *dev;
err = EINVAL;
out = stderr;
me = argv[0];
new = 0;
while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
switch (c) {
case 's':
errno = 0;
new = strtoull(optarg, NULL, 0);
if (errno) {
err = errno;
perror(argv[i]);
goto out;
}
break;
case 'h':
err = 0;
out = stdout;
goto err;
default:
perror(argv[i]);
goto err;
}
}
if (optind < argc)
dev = argv[optind++];
else
goto err;
fd = open(dev, O_RDONLY);
if (fd < 0) {
err = errno;
perror(dev);
goto out;
}
err = ioctl(fd, BLKGETSIZE64, &old);
if (err) {
err = errno;
perror("ioctl BLKGETSIZE64");
goto out;
}
if (!new) {
printf("%llu\n", old);
goto out;
}
if (new < old) {
err = EINVAL;
err_size(dev, old);
goto out;
}
if (optind < argc) {
backend = argv[optind++];
bfd = open(backend, O_WRONLY|O_APPEND);
if (bfd < 0) {
err = errno;
perror(backend);
goto out;
}
err = fstat(bfd, &st);
if (err) {
err = errno;
perror(backend);
goto out;
}
if (new < st.st_size) {
err = EINVAL;
err_size(backend, st.st_size);
goto out;
}
append = new - st.st_size;
sz = sizeof(a);
while (append > 0) {
if (append < sz)
sz = append;
ssz = write(bfd, a, sz);
if (ssz != sz) {
err = errno;
perror(backend);
goto out;
}
append -= sz;
}
err = fsync(bfd);
if (err) {
err = errno;
perror(backend);
goto out;
}
}
err = ioctl(fd, LOOP_SET_CAPACITY, new);
if (err) {
err = errno;
perror("ioctl LOOP_SET_CAPACITY");
}
goto out;
err:
usage(out);
out:
return err;
}
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Tomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31 16:23:43 -06:00
|
|
|
case LOOP_SET_CAPACITY:
|
|
|
|
err = -EPERM;
|
|
|
|
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
|
|
|
|
err = loop_set_capacity(lo, bdev);
|
|
|
|
break;
|
2005-04-16 16:20:36 -06:00
|
|
|
default:
|
|
|
|
err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
|
|
|
|
}
|
2006-03-23 04:00:38 -07:00
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
loop: fix circular locking in loop_clr_fd()
With CONFIG_PROVE_LOCKING enabled
$ losetup /dev/loop0 file
$ losetup -o 32256 /dev/loop1 /dev/loop0
$ losetup -d /dev/loop1
$ losetup -d /dev/loop0
triggers a [ INFO: possible circular locking dependency detected ]
I think this warning is a false positive.
Open/close on a loop device acquires bd_mutex of the device before
acquiring lo_ctl_mutex of the same device. For ioctl(LOOP_CLR_FD) after
acquiring lo_ctl_mutex, fput on the backing_file might acquire the bd_mutex of
a device, if backing file is a device and this is the last reference to the
file being dropped . But it is guaranteed that it is impossible to have a
circular list of backing devices.(say loop2->loop1->loop0->loop2 is not
possible), which guarantees that this can never deadlock.
So this warning should be suppressed. It is very difficult to annotate lockdep
not to warn here in the correct way. A simple way to silence lockdep could be
to mark the lo_ctl_mutex in ioctl to be a sub class, but this might mask some
other real bugs.
@@ -1164,7 +1164,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
struct loop_device *lo = bdev->bd_disk->private_data;
int err;
- mutex_lock(&lo->lo_ctl_mutex);
+ mutex_lock_nested(&lo->lo_ctl_mutex, 1);
switch (cmd) {
case LOOP_SET_FD:
err = loop_set_fd(lo, mode, bdev, arg);
Or actually marking the bd_mutex after lo_ctl_mutex as a sub class could be
a better solution.
Luckily it is easy to avoid calling fput on backing file with lo_ctl_mutex
held, so no lockdep annotation is required.
If you do not like the special handling of the lo_ctl_mutex just for the
LOOP_CLR_FD ioctl in lo_ioctl(), the mutex handling could be moved inside
each of the individual ioctl handlers and I could send you another patch.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-24 05:33:41 -06:00
|
|
|
|
|
|
|
out_unlocked:
|
2005-04-16 16:20:36 -06:00
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2006-08-29 12:06:14 -06:00
|
|
|
#ifdef CONFIG_COMPAT
|
|
|
|
struct compat_loop_info {
|
|
|
|
compat_int_t lo_number; /* ioctl r/o */
|
|
|
|
compat_dev_t lo_device; /* ioctl r/o */
|
|
|
|
compat_ulong_t lo_inode; /* ioctl r/o */
|
|
|
|
compat_dev_t lo_rdevice; /* ioctl r/o */
|
|
|
|
compat_int_t lo_offset;
|
|
|
|
compat_int_t lo_encrypt_type;
|
|
|
|
compat_int_t lo_encrypt_key_size; /* ioctl w/o */
|
|
|
|
compat_int_t lo_flags; /* ioctl r/o */
|
|
|
|
char lo_name[LO_NAME_SIZE];
|
|
|
|
unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
|
|
|
|
compat_ulong_t lo_init[2];
|
|
|
|
char reserved[4];
|
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Transfer 32-bit compatibility structure in userspace to 64-bit loop info
|
|
|
|
* - noinlined to reduce stack space usage in main part of driver
|
|
|
|
*/
|
|
|
|
static noinline int
|
2006-10-10 15:48:27 -06:00
|
|
|
loop_info64_from_compat(const struct compat_loop_info __user *arg,
|
2006-08-29 12:06:14 -06:00
|
|
|
struct loop_info64 *info64)
|
|
|
|
{
|
|
|
|
struct compat_loop_info info;
|
|
|
|
|
|
|
|
if (copy_from_user(&info, arg, sizeof(info)))
|
|
|
|
return -EFAULT;
|
|
|
|
|
|
|
|
memset(info64, 0, sizeof(*info64));
|
|
|
|
info64->lo_number = info.lo_number;
|
|
|
|
info64->lo_device = info.lo_device;
|
|
|
|
info64->lo_inode = info.lo_inode;
|
|
|
|
info64->lo_rdevice = info.lo_rdevice;
|
|
|
|
info64->lo_offset = info.lo_offset;
|
|
|
|
info64->lo_sizelimit = 0;
|
|
|
|
info64->lo_encrypt_type = info.lo_encrypt_type;
|
|
|
|
info64->lo_encrypt_key_size = info.lo_encrypt_key_size;
|
|
|
|
info64->lo_flags = info.lo_flags;
|
|
|
|
info64->lo_init[0] = info.lo_init[0];
|
|
|
|
info64->lo_init[1] = info.lo_init[1];
|
|
|
|
if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
|
|
memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE);
|
|
|
|
else
|
|
|
|
memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE);
|
|
|
|
memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Transfer 64-bit loop info to 32-bit compatibility structure in userspace
|
|
|
|
* - noinlined to reduce stack space usage in main part of driver
|
|
|
|
*/
|
|
|
|
static noinline int
|
|
|
|
loop_info64_to_compat(const struct loop_info64 *info64,
|
|
|
|
struct compat_loop_info __user *arg)
|
|
|
|
{
|
|
|
|
struct compat_loop_info info;
|
|
|
|
|
|
|
|
memset(&info, 0, sizeof(info));
|
|
|
|
info.lo_number = info64->lo_number;
|
|
|
|
info.lo_device = info64->lo_device;
|
|
|
|
info.lo_inode = info64->lo_inode;
|
|
|
|
info.lo_rdevice = info64->lo_rdevice;
|
|
|
|
info.lo_offset = info64->lo_offset;
|
|
|
|
info.lo_encrypt_type = info64->lo_encrypt_type;
|
|
|
|
info.lo_encrypt_key_size = info64->lo_encrypt_key_size;
|
|
|
|
info.lo_flags = info64->lo_flags;
|
|
|
|
info.lo_init[0] = info64->lo_init[0];
|
|
|
|
info.lo_init[1] = info64->lo_init[1];
|
|
|
|
if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
|
|
|
|
memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
|
|
|
|
else
|
|
|
|
memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE);
|
|
|
|
memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
|
|
|
|
|
|
|
|
/* error in case values were truncated */
|
|
|
|
if (info.lo_device != info64->lo_device ||
|
|
|
|
info.lo_rdevice != info64->lo_rdevice ||
|
|
|
|
info.lo_inode != info64->lo_inode ||
|
|
|
|
info.lo_offset != info64->lo_offset ||
|
|
|
|
info.lo_init[0] != info64->lo_init[0] ||
|
|
|
|
info.lo_init[1] != info64->lo_init[1])
|
|
|
|
return -EOVERFLOW;
|
|
|
|
|
|
|
|
if (copy_to_user(arg, &info, sizeof(info)))
|
|
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_set_status_compat(struct loop_device *lo,
|
|
|
|
const struct compat_loop_info __user *arg)
|
|
|
|
{
|
|
|
|
struct loop_info64 info64;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
ret = loop_info64_from_compat(arg, &info64);
|
|
|
|
if (ret < 0)
|
|
|
|
return ret;
|
|
|
|
return loop_set_status(lo, &info64);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
loop_get_status_compat(struct loop_device *lo,
|
|
|
|
struct compat_loop_info __user *arg)
|
|
|
|
{
|
|
|
|
struct loop_info64 info64;
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
if (!arg)
|
|
|
|
err = -EINVAL;
|
|
|
|
if (!err)
|
|
|
|
err = loop_get_status(lo, &info64);
|
|
|
|
if (!err)
|
|
|
|
err = loop_info64_to_compat(&info64, arg);
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
|
2008-03-02 07:29:48 -07:00
|
|
|
static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
|
|
|
|
unsigned int cmd, unsigned long arg)
|
2006-08-29 12:06:14 -06:00
|
|
|
{
|
2008-03-02 07:29:48 -07:00
|
|
|
struct loop_device *lo = bdev->bd_disk->private_data;
|
2006-08-29 12:06:14 -06:00
|
|
|
int err;
|
|
|
|
|
|
|
|
switch(cmd) {
|
|
|
|
case LOOP_SET_STATUS:
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
|
|
err = loop_set_status_compat(
|
|
|
|
lo, (const struct compat_loop_info __user *) arg);
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
break;
|
|
|
|
case LOOP_GET_STATUS:
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
|
|
err = loop_get_status_compat(
|
|
|
|
lo, (struct compat_loop_info __user *) arg);
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
break;
|
loop: add ioctl to resize a loop device
Add the ability to 'resize' the loop device on the fly.
One practical application is a loop file with XFS filesystem, already
mounted: You can easily enlarge the file (append some bytes) and then call
ioctl(fd, LOOP_SET_CAPACITY, new); The loop driver will learn about the
new size and you can use xfs_growfs later on, which will allow you to use
full capacity of the loop file without the need to unmount.
Test app:
#include <linux/fs.h>
#include <linux/loop.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define _GNU_SOURCE
#include <getopt.h>
char *me;
void usage(FILE *f)
{
fprintf(f, "%s [options] loop_dev [backend_file]\n"
"-s, --set new_size_in_bytes\n"
"\twhen backend_file is given, "
"it will be expanded too while keeping the original contents\n",
me);
}
struct option opts[] = {
{
.name = "set",
.has_arg = 1,
.flag = NULL,
.val = 's'
},
{
.name = "help",
.has_arg = 0,
.flag = NULL,
.val = 'h'
}
};
void err_size(char *name, __u64 old)
{
fprintf(stderr, "size must be larger than current %s (%llu)\n",
name, old);
}
int main(int argc, char *argv[])
{
int fd, err, c, i, bfd;
ssize_t ssz;
size_t sz;
__u64 old, new, append;
char a[BUFSIZ];
struct stat st;
FILE *out;
char *backend, *dev;
err = EINVAL;
out = stderr;
me = argv[0];
new = 0;
while ((c = getopt_long(argc, argv, "s:h", opts, &i)) != -1) {
switch (c) {
case 's':
errno = 0;
new = strtoull(optarg, NULL, 0);
if (errno) {
err = errno;
perror(argv[i]);
goto out;
}
break;
case 'h':
err = 0;
out = stdout;
goto err;
default:
perror(argv[i]);
goto err;
}
}
if (optind < argc)
dev = argv[optind++];
else
goto err;
fd = open(dev, O_RDONLY);
if (fd < 0) {
err = errno;
perror(dev);
goto out;
}
err = ioctl(fd, BLKGETSIZE64, &old);
if (err) {
err = errno;
perror("ioctl BLKGETSIZE64");
goto out;
}
if (!new) {
printf("%llu\n", old);
goto out;
}
if (new < old) {
err = EINVAL;
err_size(dev, old);
goto out;
}
if (optind < argc) {
backend = argv[optind++];
bfd = open(backend, O_WRONLY|O_APPEND);
if (bfd < 0) {
err = errno;
perror(backend);
goto out;
}
err = fstat(bfd, &st);
if (err) {
err = errno;
perror(backend);
goto out;
}
if (new < st.st_size) {
err = EINVAL;
err_size(backend, st.st_size);
goto out;
}
append = new - st.st_size;
sz = sizeof(a);
while (append > 0) {
if (append < sz)
sz = append;
ssz = write(bfd, a, sz);
if (ssz != sz) {
err = errno;
perror(backend);
goto out;
}
append -= sz;
}
err = fsync(bfd);
if (err) {
err = errno;
perror(backend);
goto out;
}
}
err = ioctl(fd, LOOP_SET_CAPACITY, new);
if (err) {
err = errno;
perror("ioctl LOOP_SET_CAPACITY");
}
goto out;
err:
usage(out);
out:
return err;
}
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Tomas Matejicek <tomas@slax.org>
Cc: <util-linux-ng@vger.kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: <linux-api@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-31 16:23:43 -06:00
|
|
|
case LOOP_SET_CAPACITY:
|
2006-08-29 12:06:14 -06:00
|
|
|
case LOOP_CLR_FD:
|
|
|
|
case LOOP_GET_STATUS64:
|
|
|
|
case LOOP_SET_STATUS64:
|
|
|
|
arg = (unsigned long) compat_ptr(arg);
|
|
|
|
case LOOP_SET_FD:
|
|
|
|
case LOOP_CHANGE_FD:
|
2008-03-02 07:29:48 -07:00
|
|
|
err = lo_ioctl(bdev, mode, cmd, arg);
|
2006-08-29 12:06:14 -06:00
|
|
|
break;
|
|
|
|
default:
|
|
|
|
err = -ENOIOCTLCMD;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
return err;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2008-03-02 07:29:48 -07:00
|
|
|
static int lo_open(struct block_device *bdev, fmode_t mode)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
struct loop_device *lo;
|
|
|
|
int err = 0;
|
|
|
|
|
|
|
|
mutex_lock(&loop_index_mutex);
|
|
|
|
lo = bdev->bd_disk->private_data;
|
|
|
|
if (!lo) {
|
|
|
|
err = -ENXIO;
|
|
|
|
goto out;
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2006-03-23 04:00:38 -07:00
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
2005-04-16 16:20:36 -06:00
|
|
|
lo->lo_refcnt++;
|
2006-03-23 04:00:38 -07:00
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
out:
|
|
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
return err;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2013-05-05 19:52:57 -06:00
|
|
|
static void lo_release(struct gendisk *disk, fmode_t mode)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2008-03-02 07:29:48 -07:00
|
|
|
struct loop_device *lo = disk->private_data;
|
2009-04-07 05:48:21 -06:00
|
|
|
int err;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2006-03-23 04:00:38 -07:00
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
2008-02-06 02:36:27 -07:00
|
|
|
|
2008-12-12 06:48:27 -07:00
|
|
|
if (--lo->lo_refcnt)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
|
|
|
|
/*
|
|
|
|
* In autoclear mode, stop the loop thread
|
|
|
|
* and remove configuration after last close.
|
|
|
|
*/
|
2011-09-21 02:02:13 -06:00
|
|
|
err = loop_clr_fd(lo);
|
2009-04-07 05:48:21 -06:00
|
|
|
if (!err)
|
2013-05-05 19:52:57 -06:00
|
|
|
return;
|
2008-12-12 06:48:27 -07:00
|
|
|
} else {
|
|
|
|
/*
|
|
|
|
* Otherwise keep thread (if running) and config,
|
|
|
|
* but flush possible ongoing bios in thread.
|
|
|
|
*/
|
|
|
|
loop_flush(lo);
|
|
|
|
}
|
2008-02-06 02:36:27 -07:00
|
|
|
|
2008-12-12 06:48:27 -07:00
|
|
|
out:
|
2006-03-23 04:00:38 -07:00
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2009-09-21 18:01:13 -06:00
|
|
|
static const struct block_device_operations lo_fops = {
|
2005-04-16 16:20:36 -06:00
|
|
|
.owner = THIS_MODULE,
|
2008-03-02 07:29:48 -07:00
|
|
|
.open = lo_open,
|
|
|
|
.release = lo_release,
|
|
|
|
.ioctl = lo_ioctl,
|
2006-08-29 12:06:14 -06:00
|
|
|
#ifdef CONFIG_COMPAT
|
2008-03-02 07:29:48 -07:00
|
|
|
.compat_ioctl = lo_compat_ioctl,
|
2006-08-29 12:06:14 -06:00
|
|
|
#endif
|
2005-04-16 16:20:36 -06:00
|
|
|
};
|
|
|
|
|
|
|
|
/*
|
|
|
|
* And now the modules code and kernel interface.
|
|
|
|
*/
|
2007-05-08 01:28:20 -06:00
|
|
|
static int max_loop;
|
2011-05-26 23:59:25 -06:00
|
|
|
module_param(max_loop, int, S_IRUGO);
|
2007-06-08 14:46:44 -06:00
|
|
|
MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
|
2011-05-26 23:59:25 -06:00
|
|
|
module_param(max_part, int, S_IRUGO);
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
|
2005-04-16 16:20:36 -06:00
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
|
|
|
|
|
|
|
|
int loop_register_transfer(struct loop_func_table *funcs)
|
|
|
|
{
|
|
|
|
unsigned int n = funcs->number;
|
|
|
|
|
|
|
|
if (n >= MAX_LO_CRYPT || xfer_funcs[n])
|
|
|
|
return -EINVAL;
|
|
|
|
xfer_funcs[n] = funcs;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
static int unregister_transfer_cb(int id, void *ptr, void *data)
|
|
|
|
{
|
|
|
|
struct loop_device *lo = ptr;
|
|
|
|
struct loop_func_table *xfer = data;
|
|
|
|
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
|
|
if (lo->lo_encryption == xfer)
|
|
|
|
loop_release_xfer(lo);
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2005-04-16 16:20:36 -06:00
|
|
|
int loop_unregister_transfer(int number)
|
|
|
|
{
|
|
|
|
unsigned int n = number;
|
|
|
|
struct loop_func_table *xfer;
|
|
|
|
|
|
|
|
if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
xfer_funcs[n] = NULL;
|
2011-07-31 14:08:04 -06:00
|
|
|
idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer);
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
EXPORT_SYMBOL(loop_register_transfer);
|
|
|
|
EXPORT_SYMBOL(loop_unregister_transfer);
|
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
|
|
|
|
const struct blk_mq_queue_data *bd)
|
|
|
|
{
|
|
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
|
|
|
|
|
|
|
|
blk_mq_start_request(bd->rq);
|
|
|
|
|
|
|
|
if (cmd->rq->cmd_flags & REQ_WRITE) {
|
|
|
|
struct loop_device *lo = cmd->rq->q->queuedata;
|
|
|
|
bool need_sched = true;
|
|
|
|
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
|
|
if (lo->write_started)
|
|
|
|
need_sched = false;
|
|
|
|
else
|
|
|
|
lo->write_started = true;
|
|
|
|
list_add_tail(&cmd->list, &lo->write_cmd_head);
|
|
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
|
|
|
|
if (need_sched)
|
|
|
|
queue_work(loop_wq, &lo->write_work);
|
|
|
|
} else {
|
|
|
|
queue_work(loop_wq, &cmd->read_work);
|
|
|
|
}
|
|
|
|
|
|
|
|
return BLK_MQ_RQ_QUEUE_OK;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void loop_handle_cmd(struct loop_cmd *cmd)
|
|
|
|
{
|
|
|
|
const bool write = cmd->rq->cmd_flags & REQ_WRITE;
|
|
|
|
struct loop_device *lo = cmd->rq->q->queuedata;
|
|
|
|
int ret = -EIO;
|
|
|
|
|
|
|
|
if (lo->lo_state != Lo_bound)
|
|
|
|
goto failed;
|
|
|
|
|
|
|
|
if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY))
|
|
|
|
goto failed;
|
|
|
|
|
2014-12-31 06:22:58 -07:00
|
|
|
ret = do_req_filebacked(lo, cmd->rq);
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
|
|
|
|
failed:
|
|
|
|
if (ret)
|
|
|
|
cmd->rq->errors = -EIO;
|
|
|
|
blk_mq_complete_request(cmd->rq);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void loop_queue_write_work(struct work_struct *work)
|
|
|
|
{
|
|
|
|
struct loop_device *lo =
|
|
|
|
container_of(work, struct loop_device, write_work);
|
|
|
|
LIST_HEAD(cmd_list);
|
|
|
|
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
|
|
repeat:
|
|
|
|
list_splice_init(&lo->write_cmd_head, &cmd_list);
|
|
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
|
|
|
|
while (!list_empty(&cmd_list)) {
|
|
|
|
struct loop_cmd *cmd = list_first_entry(&cmd_list,
|
|
|
|
struct loop_cmd, list);
|
|
|
|
list_del_init(&cmd->list);
|
|
|
|
loop_handle_cmd(cmd);
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_lock_irq(&lo->lo_lock);
|
|
|
|
if (!list_empty(&lo->write_cmd_head))
|
|
|
|
goto repeat;
|
|
|
|
lo->write_started = false;
|
|
|
|
spin_unlock_irq(&lo->lo_lock);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void loop_queue_read_work(struct work_struct *work)
|
|
|
|
{
|
|
|
|
struct loop_cmd *cmd =
|
|
|
|
container_of(work, struct loop_cmd, read_work);
|
|
|
|
|
|
|
|
loop_handle_cmd(cmd);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int loop_init_request(void *data, struct request *rq,
|
|
|
|
unsigned int hctx_idx, unsigned int request_idx,
|
|
|
|
unsigned int numa_node)
|
|
|
|
{
|
|
|
|
struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
|
|
|
|
|
|
|
|
cmd->rq = rq;
|
|
|
|
INIT_WORK(&cmd->read_work, loop_queue_read_work);
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct blk_mq_ops loop_mq_ops = {
|
|
|
|
.queue_rq = loop_queue_rq,
|
|
|
|
.map_queue = blk_mq_map_queue,
|
|
|
|
.init_request = loop_init_request,
|
|
|
|
};
|
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
static int loop_add(struct loop_device **l, int i)
|
2007-05-08 01:28:20 -06:00
|
|
|
{
|
|
|
|
struct loop_device *lo;
|
|
|
|
struct gendisk *disk;
|
2011-07-31 14:08:04 -06:00
|
|
|
int err;
|
2007-05-08 01:28:20 -06:00
|
|
|
|
2012-07-14 16:39:58 -06:00
|
|
|
err = -ENOMEM;
|
2007-05-08 01:28:20 -06:00
|
|
|
lo = kzalloc(sizeof(*lo), GFP_KERNEL);
|
2012-07-14 16:39:58 -06:00
|
|
|
if (!lo)
|
2007-05-08 01:28:20 -06:00
|
|
|
goto out;
|
2011-07-31 14:08:04 -06:00
|
|
|
|
2013-10-15 14:14:38 -06:00
|
|
|
lo->lo_state = Lo_unbound;
|
|
|
|
|
2013-02-27 18:03:58 -07:00
|
|
|
/* allocate id, if @id >= 0, we're requesting that specific id */
|
2011-07-31 14:08:04 -06:00
|
|
|
if (i >= 0) {
|
2013-02-27 18:03:58 -07:00
|
|
|
err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
|
|
|
|
if (err == -ENOSPC)
|
2011-07-31 14:08:04 -06:00
|
|
|
err = -EEXIST;
|
|
|
|
} else {
|
2013-02-27 18:03:58 -07:00
|
|
|
err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
|
2011-07-31 14:08:04 -06:00
|
|
|
}
|
|
|
|
if (err < 0)
|
|
|
|
goto out_free_dev;
|
2013-02-27 18:03:58 -07:00
|
|
|
i = err;
|
2007-05-08 01:28:20 -06:00
|
|
|
|
2013-03-22 08:59:19 -06:00
|
|
|
err = -ENOMEM;
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
lo->tag_set.ops = &loop_mq_ops;
|
|
|
|
lo->tag_set.nr_hw_queues = 1;
|
|
|
|
lo->tag_set.queue_depth = 128;
|
|
|
|
lo->tag_set.numa_node = NUMA_NO_NODE;
|
|
|
|
lo->tag_set.cmd_size = sizeof(struct loop_cmd);
|
|
|
|
lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
|
|
|
|
lo->tag_set.driver_data = lo;
|
|
|
|
|
|
|
|
err = blk_mq_alloc_tag_set(&lo->tag_set);
|
|
|
|
if (err)
|
2013-10-14 10:12:24 -06:00
|
|
|
goto out_free_idr;
|
2007-05-08 01:28:20 -06:00
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
lo->lo_queue = blk_mq_init_queue(&lo->tag_set);
|
|
|
|
if (IS_ERR_OR_NULL(lo->lo_queue)) {
|
|
|
|
err = PTR_ERR(lo->lo_queue);
|
|
|
|
goto out_cleanup_tags;
|
|
|
|
}
|
2013-10-15 14:14:38 -06:00
|
|
|
lo->lo_queue->queuedata = lo;
|
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
INIT_LIST_HEAD(&lo->write_cmd_head);
|
|
|
|
INIT_WORK(&lo->write_work, loop_queue_write_work);
|
|
|
|
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
disk = lo->lo_disk = alloc_disk(1 << part_shift);
|
2007-05-08 01:28:20 -06:00
|
|
|
if (!disk)
|
|
|
|
goto out_free_queue;
|
|
|
|
|
loop: always allow userspace partitions and optionally support automatic scanning
Automatic partition scanning can be requested individually per loop
device during its setup by setting LO_FLAGS_PARTSCAN. By default, no
partition tables are scanned.
Userspace can now always add and remove partitions from all loop
devices, regardless if the in-kernel partition scanner is enabled or
not.
The needed partition minor numbers are allocated from the extended
minors space, the main loop device numbers will continue to match the
loop minors, regardless of the number of partitions used.
# grep . /sys/class/block/loop1/loop/*
/sys/block/loop1/loop/autoclear:0
/sys/block/loop1/loop/backing_file:/home/kay/data/stuff/part.img
/sys/block/loop1/loop/offset:0
/sys/block/loop1/loop/partscan:1
/sys/block/loop1/loop/sizelimit:0
# ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 Aug 14 20:22 /dev/loop0
brw-rw---- 1 root disk 7, 1 Aug 14 20:23 /dev/loop1
brw-rw---- 1 root disk 259, 0 Aug 14 20:23 /dev/loop1p1
brw-rw---- 1 root disk 259, 1 Aug 14 20:23 /dev/loop1p2
brw-rw---- 1 root disk 7, 99 Aug 14 20:23 /dev/loop99
brw-rw---- 1 root disk 259, 2 Aug 14 20:23 /dev/loop99p1
brw-rw---- 1 root disk 259, 3 Aug 14 20:23 /dev/loop99p2
crw------T 1 root root 10, 237 Aug 14 20:22 /dev/loop-control
Cc: Karel Zak <kzak@redhat.com>
Cc: Davidlohr Bueso <dave@gnu.org>
Acked-By: Tejun Heo <tj@kernel.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 12:12:04 -06:00
|
|
|
/*
|
|
|
|
* Disable partition scanning by default. The in-kernel partition
|
|
|
|
* scanning can be requested individually per-device during its
|
|
|
|
* setup. Userspace can always add and remove partitions from all
|
|
|
|
* devices. The needed partition minors are allocated from the
|
|
|
|
* extended minor space, the main loop device numbers will continue
|
|
|
|
* to match the loop minors, regardless of the number of partitions
|
|
|
|
* used.
|
|
|
|
*
|
|
|
|
* If max_part is given, partition scanning is globally enabled for
|
|
|
|
* all loop devices. The minors for the main loop devices will be
|
|
|
|
* multiples of max_part.
|
|
|
|
*
|
|
|
|
* Note: Global-for-all-devices, set-only-at-init, read-only module
|
|
|
|
* parameteters like 'max_loop' and 'max_part' make things needlessly
|
|
|
|
* complicated, are too static, inflexible and may surprise
|
|
|
|
* userspace tools. Parameters like this in general should be avoided.
|
|
|
|
*/
|
|
|
|
if (!part_shift)
|
|
|
|
disk->flags |= GENHD_FL_NO_PART_SCAN;
|
|
|
|
disk->flags |= GENHD_FL_EXT_DEVT;
|
2007-05-08 01:28:20 -06:00
|
|
|
mutex_init(&lo->lo_ctl_mutex);
|
|
|
|
lo->lo_number = i;
|
|
|
|
spin_lock_init(&lo->lo_lock);
|
|
|
|
disk->major = LOOP_MAJOR;
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
disk->first_minor = i << part_shift;
|
2007-05-08 01:28:20 -06:00
|
|
|
disk->fops = &lo_fops;
|
|
|
|
disk->private_data = lo;
|
|
|
|
disk->queue = lo->lo_queue;
|
|
|
|
sprintf(disk->disk_name, "loop%d", i);
|
2011-07-31 14:08:04 -06:00
|
|
|
add_disk(disk);
|
|
|
|
*l = lo;
|
|
|
|
return lo->lo_number;
|
2007-05-08 01:28:20 -06:00
|
|
|
|
|
|
|
out_free_queue:
|
|
|
|
blk_cleanup_queue(lo->lo_queue);
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
out_cleanup_tags:
|
|
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
2013-10-14 10:12:24 -06:00
|
|
|
out_free_idr:
|
|
|
|
idr_remove(&loop_index_idr, i);
|
2007-05-08 01:28:20 -06:00
|
|
|
out_free_dev:
|
|
|
|
kfree(lo);
|
|
|
|
out:
|
2011-07-31 14:08:04 -06:00
|
|
|
return err;
|
2007-05-08 01:28:20 -06:00
|
|
|
}
|
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
static void loop_remove(struct loop_device *lo)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2011-07-31 14:08:04 -06:00
|
|
|
del_gendisk(lo->lo_disk);
|
2007-05-08 01:28:20 -06:00
|
|
|
blk_cleanup_queue(lo->lo_queue);
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
blk_mq_free_tag_set(&lo->tag_set);
|
2007-05-08 01:28:20 -06:00
|
|
|
put_disk(lo->lo_disk);
|
|
|
|
kfree(lo);
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
static int find_free_cb(int id, void *ptr, void *data)
|
|
|
|
{
|
|
|
|
struct loop_device *lo = ptr;
|
|
|
|
struct loop_device **l = data;
|
|
|
|
|
|
|
|
if (lo->lo_state == Lo_unbound) {
|
|
|
|
*l = lo;
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
static int loop_lookup(struct loop_device **l, int i)
|
2007-06-08 14:46:44 -06:00
|
|
|
{
|
|
|
|
struct loop_device *lo;
|
2011-07-31 14:08:04 -06:00
|
|
|
int ret = -ENODEV;
|
2007-06-08 14:46:44 -06:00
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
if (i < 0) {
|
|
|
|
int err;
|
|
|
|
|
|
|
|
err = idr_for_each(&loop_index_idr, &find_free_cb, &lo);
|
|
|
|
if (err == 1) {
|
|
|
|
*l = lo;
|
|
|
|
ret = lo->lo_number;
|
|
|
|
}
|
|
|
|
goto out;
|
2007-06-08 14:46:44 -06:00
|
|
|
}
|
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
/* lookup and return a specific i */
|
2011-07-31 14:08:04 -06:00
|
|
|
lo = idr_find(&loop_index_idr, i);
|
2007-06-08 14:46:44 -06:00
|
|
|
if (lo) {
|
2011-07-31 14:08:04 -06:00
|
|
|
*l = lo;
|
|
|
|
ret = lo->lo_number;
|
2007-06-08 14:46:44 -06:00
|
|
|
}
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
out:
|
2011-07-31 14:08:04 -06:00
|
|
|
return ret;
|
2007-06-08 14:46:44 -06:00
|
|
|
}
|
|
|
|
|
2007-05-08 01:28:20 -06:00
|
|
|
static struct kobject *loop_probe(dev_t dev, int *part, void *data)
|
|
|
|
{
|
2007-05-13 03:52:32 -06:00
|
|
|
struct loop_device *lo;
|
2007-05-12 14:23:15 -06:00
|
|
|
struct kobject *kobj;
|
2011-07-31 14:08:04 -06:00
|
|
|
int err;
|
2007-05-08 01:28:20 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
mutex_lock(&loop_index_mutex);
|
|
|
|
err = loop_lookup(&lo, MINOR(dev) >> part_shift);
|
|
|
|
if (err < 0)
|
|
|
|
err = loop_add(&lo, MINOR(dev) >> part_shift);
|
|
|
|
if (err < 0)
|
2013-10-14 10:13:24 -06:00
|
|
|
kobj = NULL;
|
2011-07-31 14:08:04 -06:00
|
|
|
else
|
|
|
|
kobj = get_disk(lo->lo_disk);
|
|
|
|
mutex_unlock(&loop_index_mutex);
|
2007-05-08 01:28:20 -06:00
|
|
|
|
|
|
|
*part = 0;
|
2007-05-12 14:23:15 -06:00
|
|
|
return kobj;
|
2007-05-08 01:28:20 -06:00
|
|
|
}
|
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
static long loop_control_ioctl(struct file *file, unsigned int cmd,
|
|
|
|
unsigned long parm)
|
|
|
|
{
|
|
|
|
struct loop_device *lo;
|
|
|
|
int ret = -ENOSYS;
|
|
|
|
|
|
|
|
mutex_lock(&loop_index_mutex);
|
|
|
|
switch (cmd) {
|
|
|
|
case LOOP_CTL_ADD:
|
|
|
|
ret = loop_lookup(&lo, parm);
|
|
|
|
if (ret >= 0) {
|
|
|
|
ret = -EEXIST;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
ret = loop_add(&lo, parm);
|
|
|
|
break;
|
|
|
|
case LOOP_CTL_REMOVE:
|
|
|
|
ret = loop_lookup(&lo, parm);
|
|
|
|
if (ret < 0)
|
|
|
|
break;
|
|
|
|
mutex_lock(&lo->lo_ctl_mutex);
|
|
|
|
if (lo->lo_state != Lo_unbound) {
|
|
|
|
ret = -EBUSY;
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (lo->lo_refcnt > 0) {
|
|
|
|
ret = -EBUSY;
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
lo->lo_disk->private_data = NULL;
|
|
|
|
mutex_unlock(&lo->lo_ctl_mutex);
|
|
|
|
idr_remove(&loop_index_idr, lo->lo_number);
|
|
|
|
loop_remove(lo);
|
|
|
|
break;
|
|
|
|
case LOOP_CTL_GET_FREE:
|
|
|
|
ret = loop_lookup(&lo, -1);
|
|
|
|
if (ret >= 0)
|
|
|
|
break;
|
|
|
|
ret = loop_add(&lo, -1);
|
|
|
|
}
|
|
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static const struct file_operations loop_ctl_fops = {
|
|
|
|
.open = nonseekable_open,
|
|
|
|
.unlocked_ioctl = loop_control_ioctl,
|
|
|
|
.compat_ioctl = loop_control_ioctl,
|
|
|
|
.owner = THIS_MODULE,
|
|
|
|
.llseek = noop_llseek,
|
|
|
|
};
|
|
|
|
|
|
|
|
static struct miscdevice loop_misc = {
|
|
|
|
.minor = LOOP_CTRL_MINOR,
|
|
|
|
.name = "loop-control",
|
|
|
|
.fops = &loop_ctl_fops,
|
|
|
|
};
|
|
|
|
|
|
|
|
MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR);
|
|
|
|
MODULE_ALIAS("devname:loop-control");
|
|
|
|
|
2007-05-08 01:28:20 -06:00
|
|
|
static int __init loop_init(void)
|
|
|
|
{
|
2007-06-08 14:46:44 -06:00
|
|
|
int i, nr;
|
|
|
|
unsigned long range;
|
2011-07-31 14:08:04 -06:00
|
|
|
struct loop_device *lo;
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
int err;
|
2007-06-08 14:46:44 -06:00
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
err = misc_register(&loop_misc);
|
|
|
|
if (err < 0)
|
|
|
|
return err;
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
|
|
|
|
part_shift = 0;
|
2011-05-26 23:59:25 -06:00
|
|
|
if (max_part > 0) {
|
loop: manage partitions in disk image
This patch allows to use loop device with partitionned disk image.
Original behavior of loop is not modified.
A new parameter is introduced to define how many partition we want to be
able to manage per loop device. This parameter is "max_part".
For instance, to manage 63 partitions / loop device, we will do:
# modprobe loop max_part=63
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
And to attach a raw partitionned disk image, the original losetup is used:
# losetup -f etch.img
# ls -l /dev/loop?*
brw-rw---- 1 root disk 7, 0 2008-03-05 14:55 /dev/loop0
brw-rw---- 1 root disk 7, 1 2008-03-05 14:57 /dev/loop0p1
brw-rw---- 1 root disk 7, 2 2008-03-05 14:57 /dev/loop0p2
brw-rw---- 1 root disk 7, 5 2008-03-05 14:57 /dev/loop0p5
brw-rw---- 1 root disk 7, 64 2008-03-05 14:55 /dev/loop1
brw-rw---- 1 root disk 7, 128 2008-03-05 14:55 /dev/loop2
brw-rw---- 1 root disk 7, 192 2008-03-05 14:55 /dev/loop3
brw-rw---- 1 root disk 7, 256 2008-03-05 14:55 /dev/loop4
brw-rw---- 1 root disk 7, 320 2008-03-05 14:55 /dev/loop5
brw-rw---- 1 root disk 7, 384 2008-03-05 14:55 /dev/loop6
brw-rw---- 1 root disk 7, 448 2008-03-05 14:55 /dev/loop7
# mount /dev/loop0p1 /mnt
# ls /mnt
bench cdrom home lib mnt root srv usr
bin dev initrd lost+found opt sbin sys var
boot etc initrd.img media proc selinux tmp vmlinuz
# umount /mnt
# losetup -d /dev/loop0
Of course, the same behavior can be done using kpartx on a loop device,
but modifying loop avoids to stack several layers of block device (loop +
device mapper), this is a very light modification (40% of modifications
are to manage the new parameter).
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-26 05:11:53 -06:00
|
|
|
part_shift = fls(max_part);
|
|
|
|
|
2011-05-26 23:59:25 -06:00
|
|
|
/*
|
|
|
|
* Adjust max_part according to part_shift as it is exported
|
|
|
|
* to user space so that user can decide correct minor number
|
|
|
|
* if [s]he want to create more devices.
|
|
|
|
*
|
|
|
|
* Note that -1 is required because partition 0 is reserved
|
|
|
|
* for the whole disk.
|
|
|
|
*/
|
|
|
|
max_part = (1UL << part_shift) - 1;
|
|
|
|
}
|
|
|
|
|
2013-02-21 16:16:49 -07:00
|
|
|
if ((1UL << part_shift) > DISK_MAX_PARTS) {
|
|
|
|
err = -EINVAL;
|
|
|
|
goto misc_out;
|
|
|
|
}
|
2011-05-24 08:48:54 -06:00
|
|
|
|
2013-02-21 16:16:49 -07:00
|
|
|
if (max_loop > 1UL << (MINORBITS - part_shift)) {
|
|
|
|
err = -EINVAL;
|
|
|
|
goto misc_out;
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
/*
|
|
|
|
* If max_loop is specified, create that many devices upfront.
|
|
|
|
* This also becomes a hard limit. If max_loop is not specified,
|
|
|
|
* create CONFIG_BLK_DEV_LOOP_MIN_COUNT loop devices at module
|
|
|
|
* init time. Loop devices can be requested on-demand with the
|
|
|
|
* /dev/loop-control interface, or be instantiated by accessing
|
|
|
|
* a 'dead' device node.
|
|
|
|
*/
|
2007-05-08 01:28:20 -06:00
|
|
|
if (max_loop) {
|
2007-06-08 14:46:44 -06:00
|
|
|
nr = max_loop;
|
loop: handle on-demand devices correctly
When finding or allocating a loop device, loop_probe() did not take
partition numbers into account so that it can result to a different
device. Consider following example:
$ sudo modprobe loop max_part=15
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
$ sudo mknod /dev/loop8 b 7 128
$ sudo losetup /dev/loop8 ~/temp/disk-with-3-parts.img
$ sudo losetup -a
/dev/loop128: [0805]:278201 (/home/namhyung/temp/disk-with-3-parts.img)
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 2048 2011-05-24 22:18 /dev/loop128
brw-rw---- 1 root disk 7, 2049 2011-05-24 22:18 /dev/loop128p1
brw-rw---- 1 root disk 7, 2050 2011-05-24 22:18 /dev/loop128p2
brw-rw---- 1 root disk 7, 2051 2011-05-24 22:18 /dev/loop128p3
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
brw-r--r-- 1 root root 7, 128 2011-05-24 22:17 /dev/loop8
After this patch, /dev/loop8 - instead of /dev/loop128 - was
accessed correctly.
In addition, 'range' passed to blk_register_region() should
include all range of dev_t that LOOP_MAJOR can address. It does
not need to be limited by partition numbers unless 'max_loop'
param was specified.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-24 08:48:55 -06:00
|
|
|
range = max_loop << part_shift;
|
2007-06-08 14:46:44 -06:00
|
|
|
} else {
|
2011-07-31 14:08:04 -06:00
|
|
|
nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
|
loop: handle on-demand devices correctly
When finding or allocating a loop device, loop_probe() did not take
partition numbers into account so that it can result to a different
device. Consider following example:
$ sudo modprobe loop max_part=15
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
$ sudo mknod /dev/loop8 b 7 128
$ sudo losetup /dev/loop8 ~/temp/disk-with-3-parts.img
$ sudo losetup -a
/dev/loop128: [0805]:278201 (/home/namhyung/temp/disk-with-3-parts.img)
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 2048 2011-05-24 22:18 /dev/loop128
brw-rw---- 1 root disk 7, 2049 2011-05-24 22:18 /dev/loop128p1
brw-rw---- 1 root disk 7, 2050 2011-05-24 22:18 /dev/loop128p2
brw-rw---- 1 root disk 7, 2051 2011-05-24 22:18 /dev/loop128p3
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
brw-r--r-- 1 root root 7, 128 2011-05-24 22:17 /dev/loop8
After this patch, /dev/loop8 - instead of /dev/loop128 - was
accessed correctly.
In addition, 'range' passed to blk_register_region() should
include all range of dev_t that LOOP_MAJOR can address. It does
not need to be limited by partition numbers unless 'max_loop'
param was specified.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-24 08:48:55 -06:00
|
|
|
range = 1UL << MINORBITS;
|
2007-06-08 14:46:44 -06:00
|
|
|
}
|
|
|
|
|
2013-02-21 16:16:49 -07:00
|
|
|
if (register_blkdev(LOOP_MAJOR, "loop")) {
|
|
|
|
err = -EIO;
|
|
|
|
goto misc_out;
|
|
|
|
}
|
2005-04-16 16:20:36 -06:00
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
loop_wq = alloc_workqueue("kloopd",
|
|
|
|
WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0);
|
|
|
|
if (!loop_wq) {
|
|
|
|
err = -ENOMEM;
|
|
|
|
goto misc_out;
|
|
|
|
}
|
|
|
|
|
2007-06-08 14:46:44 -06:00
|
|
|
blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
|
|
|
|
THIS_MODULE, loop_probe, NULL, NULL);
|
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
/* pre-create number of devices given by config or max_loop */
|
2011-07-31 14:08:04 -06:00
|
|
|
mutex_lock(&loop_index_mutex);
|
|
|
|
for (i = 0; i < nr; i++)
|
|
|
|
loop_add(&lo, i);
|
|
|
|
mutex_unlock(&loop_index_mutex);
|
|
|
|
|
2007-05-08 01:28:20 -06:00
|
|
|
printk(KERN_INFO "loop: module loaded\n");
|
2005-04-16 16:20:36 -06:00
|
|
|
return 0;
|
2013-02-21 16:16:49 -07:00
|
|
|
|
|
|
|
misc_out:
|
|
|
|
misc_deregister(&loop_misc);
|
|
|
|
return err;
|
2011-07-31 14:08:04 -06:00
|
|
|
}
|
2007-06-08 14:46:44 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
static int loop_exit_cb(int id, void *ptr, void *data)
|
|
|
|
{
|
|
|
|
struct loop_device *lo = ptr;
|
2007-06-08 14:46:44 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
loop_remove(lo);
|
|
|
|
return 0;
|
2005-04-16 16:20:36 -06:00
|
|
|
}
|
|
|
|
|
2007-05-08 01:28:20 -06:00
|
|
|
static void __exit loop_exit(void)
|
2005-04-16 16:20:36 -06:00
|
|
|
{
|
2007-06-08 14:46:44 -06:00
|
|
|
unsigned long range;
|
2005-04-16 16:20:36 -06:00
|
|
|
|
loop: handle on-demand devices correctly
When finding or allocating a loop device, loop_probe() did not take
partition numbers into account so that it can result to a different
device. Consider following example:
$ sudo modprobe loop max_part=15
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
$ sudo mknod /dev/loop8 b 7 128
$ sudo losetup /dev/loop8 ~/temp/disk-with-3-parts.img
$ sudo losetup -a
/dev/loop128: [0805]:278201 (/home/namhyung/temp/disk-with-3-parts.img)
$ ls -l /dev/loop*
brw-rw---- 1 root disk 7, 0 2011-05-24 22:16 /dev/loop0
brw-rw---- 1 root disk 7, 16 2011-05-24 22:16 /dev/loop1
brw-rw---- 1 root disk 7, 2048 2011-05-24 22:18 /dev/loop128
brw-rw---- 1 root disk 7, 2049 2011-05-24 22:18 /dev/loop128p1
brw-rw---- 1 root disk 7, 2050 2011-05-24 22:18 /dev/loop128p2
brw-rw---- 1 root disk 7, 2051 2011-05-24 22:18 /dev/loop128p3
brw-rw---- 1 root disk 7, 32 2011-05-24 22:16 /dev/loop2
brw-rw---- 1 root disk 7, 48 2011-05-24 22:16 /dev/loop3
brw-rw---- 1 root disk 7, 64 2011-05-24 22:16 /dev/loop4
brw-rw---- 1 root disk 7, 80 2011-05-24 22:16 /dev/loop5
brw-rw---- 1 root disk 7, 96 2011-05-24 22:16 /dev/loop6
brw-rw---- 1 root disk 7, 112 2011-05-24 22:16 /dev/loop7
brw-r--r-- 1 root root 7, 128 2011-05-24 22:17 /dev/loop8
After this patch, /dev/loop8 - instead of /dev/loop128 - was
accessed correctly.
In addition, 'range' passed to blk_register_region() should
include all range of dev_t that LOOP_MAJOR can address. It does
not need to be limited by partition numbers unless 'max_loop'
param was specified.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Laurent Vivier <Laurent.Vivier@bull.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-24 08:48:55 -06:00
|
|
|
range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;
|
2007-06-08 14:46:44 -06:00
|
|
|
|
2011-07-31 14:08:04 -06:00
|
|
|
idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
|
|
|
|
idr_destroy(&loop_index_idr);
|
2007-05-08 01:28:20 -06:00
|
|
|
|
2007-06-08 14:46:44 -06:00
|
|
|
blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
|
2007-07-17 05:03:46 -06:00
|
|
|
unregister_blkdev(LOOP_MAJOR, "loop");
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
|
|
|
|
block: loop: improve performance via blk-mq
The conversion is a bit straightforward, and use work queue to
dispatch requests of loop block, and one big change is that requests
is submitted to backend file/device concurrently with work queue,
so throughput may get improved much. Given write requests over same
file are often run exclusively, so don't handle them concurrently for
avoiding extra context switch cost, possible lock contention and work
schedule cost. Also with blk-mq, there is opportunity to get loop I/O
merged before submitting to backend file/device.
In the following test:
- base: v3.19-rc2-2041231
- loop over file in ext4 file system on SSD disk
- bs: 4k, libaio, io depth: 64, O_DIRECT, num of jobs: 1
- throughput: IOPS
------------------------------------------------------
| | base | base with loop-mq | delta |
------------------------------------------------------
| randread | 1740 | 25318 | +1355%|
------------------------------------------------------
| read | 42196 | 51771 | +22.6%|
-----------------------------------------------------
| randwrite | 35709 | 34624 | -3% |
-----------------------------------------------------
| write | 39137 | 40326 | +3% |
-----------------------------------------------------
So loop-mq can improve throughput for both read and randread, meantime,
performance of write and randwrite isn't hurted basically.
Another benefit is that loop driver code gets simplified
much after blk-mq conversion, and the patch can be thought as
cleanup too.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-31 06:22:57 -07:00
|
|
|
destroy_workqueue(loop_wq);
|
|
|
|
|
loop: add management interface for on-demand device allocation
Loop devices today have a fixed pre-allocated number of usually 8.
The number can only be changed at module init time. To find a free
device to use, /dev/loop%i needs to be scanned, and all devices need
to be opened until a free one is possibly found.
This adds a new /dev/loop-control device node, that allows to
dynamically find or allocate a free device, and to add and remove loop
devices from the running system:
LOOP_CTL_ADD adds a specific device. Arg is the number
of the device. It returns the device i or a negative
error code.
LOOP_CTL_REMOVE removes a specific device, Arg is the
number the device. It returns the device i or a negative
error code.
LOOP_CTL_GET_FREE finds the next unbound device or allocates
a new one. No arg is given. It returns the device i or a
negative error code.
The loop kernel module gets automatically loaded when
/dev/loop-control is accessed the first time. The alias
specified in the module, instructs udev to create this
'dead' device node, even when the module is not loaded.
Example:
cfd = open("/dev/loop-control", O_RDWR);
# add a new specific loop device
err = ioctl(cfd, LOOP_CTL_ADD, devnr);
# remove a specific loop device
err = ioctl(cfd, LOOP_CTL_REMOVE, devnr);
# find or allocate a free loop device to use
devnr = ioctl(cfd, LOOP_CTL_GET_FREE);
sprintf(loopname, "/dev/loop%i", devnr);
ffd = open("backing-file", O_RDWR);
lfd = open(loopname, O_RDWR);
err = ioctl(lfd, LOOP_SET_FD, ffd);
Cc: Tejun Heo <tj@kernel.org>
Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-31 14:08:04 -06:00
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misc_deregister(&loop_misc);
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2005-04-16 16:20:36 -06:00
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}
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module_init(loop_init);
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module_exit(loop_exit);
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#ifndef MODULE
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static int __init max_loop_setup(char *str)
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{
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max_loop = simple_strtol(str, NULL, 0);
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return 1;
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}
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__setup("max_loop=", max_loop_setup);
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#endif
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