![Tejun Heo](/assets/img/avatar_default.png)
There are two variants of stat functions - ones prefixed with double underbars which don't care about preemption and ones without which disable preemption before manipulating per-cpu counters. It's unclear whether the underbarred ones assume that preemtion is disabled on entry as some callers don't do that. This patch unifies diskstats access by implementing disk_stat_lock() and disk_stat_unlock() which take care of both RCU (for partition access) and preemption (for per-cpu counter access). diskstats access should always be enclosed between the two functions. As such, there's no need for the versions which disables preemption. They're removed and double underbars ones are renamed to drop the underbars. As an extra argument is added, there's no danger of using the old version unconverted. disk_stat_lock() uses get_cpu() and returns the cpu index and all diskstat functions which access per-cpu counters now has @cpu argument to help RT. This change adds RCU or preemption operations at some places but also collapses several preemption ops into one at others. Overall, the performance difference should be negligible as all involved ops are very lightweight per-cpu ones. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
591 lines
14 KiB
C
591 lines
14 KiB
C
/*
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* fs/partitions/check.c
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*
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* Code extracted from drivers/block/genhd.c
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* Copyright (C) 1991-1998 Linus Torvalds
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* Re-organised Feb 1998 Russell King
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*
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* We now have independent partition support from the
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* block drivers, which allows all the partition code to
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* be grouped in one location, and it to be mostly self
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* contained.
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*
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* Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/kmod.h>
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#include <linux/ctype.h>
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#include <linux/genhd.h>
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#include "check.h"
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#include "acorn.h"
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#include "amiga.h"
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#include "atari.h"
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#include "ldm.h"
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#include "mac.h"
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#include "msdos.h"
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#include "osf.h"
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#include "sgi.h"
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#include "sun.h"
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#include "ibm.h"
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#include "ultrix.h"
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#include "efi.h"
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#include "karma.h"
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#include "sysv68.h"
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#ifdef CONFIG_BLK_DEV_MD
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extern void md_autodetect_dev(dev_t dev);
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#endif
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int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
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static int (*check_part[])(struct parsed_partitions *, struct block_device *) = {
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/*
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* Probe partition formats with tables at disk address 0
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* that also have an ADFS boot block at 0xdc0.
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*/
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#ifdef CONFIG_ACORN_PARTITION_ICS
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adfspart_check_ICS,
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#endif
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#ifdef CONFIG_ACORN_PARTITION_POWERTEC
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adfspart_check_POWERTEC,
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#endif
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#ifdef CONFIG_ACORN_PARTITION_EESOX
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adfspart_check_EESOX,
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#endif
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/*
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* Now move on to formats that only have partition info at
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* disk address 0xdc0. Since these may also have stale
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* PC/BIOS partition tables, they need to come before
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* the msdos entry.
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*/
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#ifdef CONFIG_ACORN_PARTITION_CUMANA
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adfspart_check_CUMANA,
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#endif
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#ifdef CONFIG_ACORN_PARTITION_ADFS
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adfspart_check_ADFS,
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#endif
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#ifdef CONFIG_EFI_PARTITION
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efi_partition, /* this must come before msdos */
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#endif
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#ifdef CONFIG_SGI_PARTITION
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sgi_partition,
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#endif
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#ifdef CONFIG_LDM_PARTITION
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ldm_partition, /* this must come before msdos */
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#endif
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#ifdef CONFIG_MSDOS_PARTITION
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msdos_partition,
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#endif
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#ifdef CONFIG_OSF_PARTITION
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osf_partition,
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#endif
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#ifdef CONFIG_SUN_PARTITION
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sun_partition,
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#endif
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#ifdef CONFIG_AMIGA_PARTITION
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amiga_partition,
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#endif
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#ifdef CONFIG_ATARI_PARTITION
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atari_partition,
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#endif
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#ifdef CONFIG_MAC_PARTITION
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mac_partition,
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#endif
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#ifdef CONFIG_ULTRIX_PARTITION
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ultrix_partition,
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#endif
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#ifdef CONFIG_IBM_PARTITION
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ibm_partition,
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#endif
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#ifdef CONFIG_KARMA_PARTITION
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karma_partition,
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#endif
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#ifdef CONFIG_SYSV68_PARTITION
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sysv68_partition,
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#endif
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NULL
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};
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/*
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* disk_name() is used by partition check code and the genhd driver.
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* It formats the devicename of the indicated disk into
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* the supplied buffer (of size at least 32), and returns
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* a pointer to that same buffer (for convenience).
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*/
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char *disk_name(struct gendisk *hd, int partno, char *buf)
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{
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if (!partno)
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snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
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else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
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snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
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else
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snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
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return buf;
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}
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const char *bdevname(struct block_device *bdev, char *buf)
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{
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int partno = 0;
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if (bdev->bd_part)
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partno = bdev->bd_part->partno;
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return disk_name(bdev->bd_disk, partno, buf);
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}
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EXPORT_SYMBOL(bdevname);
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/*
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* There's very little reason to use this, you should really
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* have a struct block_device just about everywhere and use
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* bdevname() instead.
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*/
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const char *__bdevname(dev_t dev, char *buffer)
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{
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scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
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MAJOR(dev), MINOR(dev));
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return buffer;
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}
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EXPORT_SYMBOL(__bdevname);
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static struct parsed_partitions *
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check_partition(struct gendisk *hd, struct block_device *bdev)
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{
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struct parsed_partitions *state;
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int i, res, err;
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state = kmalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
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if (!state)
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return NULL;
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disk_name(hd, 0, state->name);
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printk(KERN_INFO " %s:", state->name);
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if (isdigit(state->name[strlen(state->name)-1]))
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sprintf(state->name, "p");
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state->limit = disk_max_parts(hd) + 1;
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i = res = err = 0;
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while (!res && check_part[i]) {
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memset(&state->parts, 0, sizeof(state->parts));
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res = check_part[i++](state, bdev);
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if (res < 0) {
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/* We have hit an I/O error which we don't report now.
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* But record it, and let the others do their job.
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*/
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err = res;
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res = 0;
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}
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}
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if (res > 0)
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return state;
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if (err)
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/* The partition is unrecognized. So report I/O errors if there were any */
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res = err;
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if (!res)
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printk(" unknown partition table\n");
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else if (warn_no_part)
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printk(" unable to read partition table\n");
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kfree(state);
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return ERR_PTR(res);
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}
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static ssize_t part_start_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct hd_struct *p = dev_to_part(dev);
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return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
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}
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static ssize_t part_size_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct hd_struct *p = dev_to_part(dev);
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return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
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}
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static ssize_t part_stat_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct hd_struct *p = dev_to_part(dev);
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int cpu;
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cpu = disk_stat_lock();
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part_round_stats(cpu, p);
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disk_stat_unlock();
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return sprintf(buf,
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"%8lu %8lu %8llu %8u "
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"%8lu %8lu %8llu %8u "
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"%8u %8u %8u"
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"\n",
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part_stat_read(p, ios[READ]),
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part_stat_read(p, merges[READ]),
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(unsigned long long)part_stat_read(p, sectors[READ]),
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jiffies_to_msecs(part_stat_read(p, ticks[READ])),
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part_stat_read(p, ios[WRITE]),
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part_stat_read(p, merges[WRITE]),
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(unsigned long long)part_stat_read(p, sectors[WRITE]),
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jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
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p->in_flight,
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jiffies_to_msecs(part_stat_read(p, io_ticks)),
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jiffies_to_msecs(part_stat_read(p, time_in_queue)));
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}
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#ifdef CONFIG_FAIL_MAKE_REQUEST
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static ssize_t part_fail_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct hd_struct *p = dev_to_part(dev);
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return sprintf(buf, "%d\n", p->make_it_fail);
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}
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static ssize_t part_fail_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct hd_struct *p = dev_to_part(dev);
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int i;
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if (count > 0 && sscanf(buf, "%d", &i) > 0)
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p->make_it_fail = (i == 0) ? 0 : 1;
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return count;
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}
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#endif
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static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
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static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
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static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
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#ifdef CONFIG_FAIL_MAKE_REQUEST
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static struct device_attribute dev_attr_fail =
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__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
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#endif
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static struct attribute *part_attrs[] = {
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&dev_attr_start.attr,
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&dev_attr_size.attr,
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&dev_attr_stat.attr,
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#ifdef CONFIG_FAIL_MAKE_REQUEST
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&dev_attr_fail.attr,
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#endif
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NULL
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};
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static struct attribute_group part_attr_group = {
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.attrs = part_attrs,
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};
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static struct attribute_group *part_attr_groups[] = {
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&part_attr_group,
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NULL
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};
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static void part_release(struct device *dev)
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{
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struct hd_struct *p = dev_to_part(dev);
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free_part_stats(p);
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kfree(p);
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}
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struct device_type part_type = {
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.name = "partition",
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.groups = part_attr_groups,
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.release = part_release,
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};
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static inline void disk_sysfs_add_subdirs(struct gendisk *disk)
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{
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struct kobject *k;
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k = kobject_get(&disk->dev.kobj);
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disk->holder_dir = kobject_create_and_add("holders", k);
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disk->slave_dir = kobject_create_and_add("slaves", k);
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kobject_put(k);
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}
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static void delete_partition_rcu_cb(struct rcu_head *head)
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{
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struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
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part->start_sect = 0;
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part->nr_sects = 0;
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part_stat_set_all(part, 0);
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put_device(&part->dev);
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}
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void delete_partition(struct gendisk *disk, int partno)
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{
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struct hd_struct *part;
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part = disk->__part[partno-1];
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if (!part)
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return;
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rcu_assign_pointer(disk->__part[partno-1], NULL);
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kobject_put(part->holder_dir);
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device_del(&part->dev);
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call_rcu(&part->rcu_head, delete_partition_rcu_cb);
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}
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static ssize_t whole_disk_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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return 0;
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}
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static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
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whole_disk_show, NULL);
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int add_partition(struct gendisk *disk, int partno,
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sector_t start, sector_t len, int flags)
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{
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struct hd_struct *p;
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int err;
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if (disk->__part[partno - 1])
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return -EBUSY;
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p = kzalloc(sizeof(*p), GFP_KERNEL);
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if (!p)
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return -ENOMEM;
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if (!init_part_stats(p)) {
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err = -ENOMEM;
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goto out_free;
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}
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p->start_sect = start;
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p->nr_sects = len;
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p->partno = partno;
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p->policy = disk->policy;
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if (isdigit(disk->dev.bus_id[strlen(disk->dev.bus_id)-1]))
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snprintf(p->dev.bus_id, BUS_ID_SIZE,
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"%sp%d", disk->dev.bus_id, partno);
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else
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snprintf(p->dev.bus_id, BUS_ID_SIZE,
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"%s%d", disk->dev.bus_id, partno);
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device_initialize(&p->dev);
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p->dev.devt = MKDEV(disk->major, disk->first_minor + partno);
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p->dev.class = &block_class;
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p->dev.type = &part_type;
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p->dev.parent = &disk->dev;
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/* delay uevent until 'holders' subdir is created */
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p->dev.uevent_suppress = 1;
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err = device_add(&p->dev);
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if (err)
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goto out_put;
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err = -ENOMEM;
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p->holder_dir = kobject_create_and_add("holders", &p->dev.kobj);
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if (!p->holder_dir)
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goto out_del;
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p->dev.uevent_suppress = 0;
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if (flags & ADDPART_FLAG_WHOLEDISK) {
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err = device_create_file(&p->dev, &dev_attr_whole_disk);
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if (err)
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goto out_del;
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}
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/* everything is up and running, commence */
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INIT_RCU_HEAD(&p->rcu_head);
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rcu_assign_pointer(disk->__part[partno - 1], p);
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/* suppress uevent if the disk supresses it */
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if (!disk->dev.uevent_suppress)
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kobject_uevent(&p->dev.kobj, KOBJ_ADD);
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return 0;
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out_free:
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kfree(p);
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return err;
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out_del:
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kobject_put(p->holder_dir);
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device_del(&p->dev);
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out_put:
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put_device(&p->dev);
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return err;
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}
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/* Not exported, helper to add_disk(). */
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void register_disk(struct gendisk *disk)
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{
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struct block_device *bdev;
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struct disk_part_iter piter;
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struct hd_struct *part;
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char *s;
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int err;
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disk->dev.parent = disk->driverfs_dev;
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strlcpy(disk->dev.bus_id, disk->disk_name, BUS_ID_SIZE);
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/* ewww... some of these buggers have / in the name... */
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s = strchr(disk->dev.bus_id, '/');
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if (s)
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*s = '!';
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/* delay uevents, until we scanned partition table */
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disk->dev.uevent_suppress = 1;
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if (device_add(&disk->dev))
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return;
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#ifndef CONFIG_SYSFS_DEPRECATED
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err = sysfs_create_link(block_depr, &disk->dev.kobj,
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kobject_name(&disk->dev.kobj));
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if (err) {
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device_del(&disk->dev);
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return;
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}
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#endif
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disk_sysfs_add_subdirs(disk);
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/* No minors to use for partitions */
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if (!disk_max_parts(disk))
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goto exit;
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/* No such device (e.g., media were just removed) */
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if (!get_capacity(disk))
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goto exit;
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bdev = bdget_disk(disk, 0);
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if (!bdev)
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goto exit;
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bdev->bd_invalidated = 1;
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err = blkdev_get(bdev, FMODE_READ, 0);
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if (err < 0)
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goto exit;
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blkdev_put(bdev);
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exit:
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/* announce disk after possible partitions are created */
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disk->dev.uevent_suppress = 0;
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kobject_uevent(&disk->dev.kobj, KOBJ_ADD);
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/* announce possible partitions */
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disk_part_iter_init(&piter, disk, 0);
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while ((part = disk_part_iter_next(&piter)))
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kobject_uevent(&part->dev.kobj, KOBJ_ADD);
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disk_part_iter_exit(&piter);
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}
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int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
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{
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struct disk_part_iter piter;
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struct hd_struct *part;
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struct parsed_partitions *state;
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int p, res;
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if (bdev->bd_part_count)
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return -EBUSY;
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res = invalidate_partition(disk, 0);
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if (res)
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return res;
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bdev->bd_invalidated = 0;
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disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
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while ((part = disk_part_iter_next(&piter)))
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delete_partition(disk, part->partno);
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disk_part_iter_exit(&piter);
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if (disk->fops->revalidate_disk)
|
|
disk->fops->revalidate_disk(disk);
|
|
if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
|
|
return 0;
|
|
if (IS_ERR(state)) /* I/O error reading the partition table */
|
|
return -EIO;
|
|
|
|
/* tell userspace that the media / partition table may have changed */
|
|
kobject_uevent(&disk->dev.kobj, KOBJ_CHANGE);
|
|
|
|
for (p = 1; p < state->limit; p++) {
|
|
sector_t size = state->parts[p].size;
|
|
sector_t from = state->parts[p].from;
|
|
if (!size)
|
|
continue;
|
|
if (from + size > get_capacity(disk)) {
|
|
printk(KERN_WARNING
|
|
"%s: p%d exceeds device capacity\n",
|
|
disk->disk_name, p);
|
|
}
|
|
res = add_partition(disk, p, from, size, state->parts[p].flags);
|
|
if (res) {
|
|
printk(KERN_ERR " %s: p%d could not be added: %d\n",
|
|
disk->disk_name, p, -res);
|
|
continue;
|
|
}
|
|
#ifdef CONFIG_BLK_DEV_MD
|
|
if (state->parts[p].flags & ADDPART_FLAG_RAID)
|
|
md_autodetect_dev(bdev->bd_dev+p);
|
|
#endif
|
|
}
|
|
kfree(state);
|
|
return 0;
|
|
}
|
|
|
|
unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
|
|
{
|
|
struct address_space *mapping = bdev->bd_inode->i_mapping;
|
|
struct page *page;
|
|
|
|
page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
|
|
NULL);
|
|
if (!IS_ERR(page)) {
|
|
if (PageError(page))
|
|
goto fail;
|
|
p->v = page;
|
|
return (unsigned char *)page_address(page) + ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
|
|
fail:
|
|
page_cache_release(page);
|
|
}
|
|
p->v = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
EXPORT_SYMBOL(read_dev_sector);
|
|
|
|
void del_gendisk(struct gendisk *disk)
|
|
{
|
|
struct disk_part_iter piter;
|
|
struct hd_struct *part;
|
|
|
|
/* invalidate stuff */
|
|
disk_part_iter_init(&piter, disk,
|
|
DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
|
|
while ((part = disk_part_iter_next(&piter))) {
|
|
invalidate_partition(disk, part->partno);
|
|
delete_partition(disk, part->partno);
|
|
}
|
|
disk_part_iter_exit(&piter);
|
|
|
|
invalidate_partition(disk, 0);
|
|
disk->capacity = 0;
|
|
disk->flags &= ~GENHD_FL_UP;
|
|
unlink_gendisk(disk);
|
|
disk_stat_set_all(disk, 0);
|
|
disk->stamp = 0;
|
|
|
|
kobject_put(disk->holder_dir);
|
|
kobject_put(disk->slave_dir);
|
|
disk->driverfs_dev = NULL;
|
|
#ifndef CONFIG_SYSFS_DEPRECATED
|
|
sysfs_remove_link(block_depr, disk->dev.bus_id);
|
|
#endif
|
|
device_del(&disk->dev);
|
|
}
|