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34404 commits

Author SHA1 Message Date
Rik van Riel 34e431b0ae /proc/meminfo: provide estimated available memory
Many load balancing and workload placing programs check /proc/meminfo to
estimate how much free memory is available.  They generally do this by
adding up "free" and "cached", which was fine ten years ago, but is
pretty much guaranteed to be wrong today.

It is wrong because Cached includes memory that is not freeable as page
cache, for example shared memory segments, tmpfs, and ramfs, and it does
not include reclaimable slab memory, which can take up a large fraction
of system memory on mostly idle systems with lots of files.

Currently, the amount of memory that is available for a new workload,
without pushing the system into swap, can be estimated from MemFree,
Active(file), Inactive(file), and SReclaimable, as well as the "low"
watermarks from /proc/zoneinfo.

However, this may change in the future, and user space really should not
be expected to know kernel internals to come up with an estimate for the
amount of free memory.

It is more convenient to provide such an estimate in /proc/meminfo.  If
things change in the future, we only have to change it in one place.

Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Erik Mouw <erik.mouw_2@nxp.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:43 -08:00
Paul Gortmaker af52b040eb fs/ramfs: don't use module_init for non-modular core code
The ramfs is always built in.  It will never be modular, so using
module_init as an alias for __initcall is rather misleading.

Fix this up now, so that we can relocate module_init from init.h into
module.h in the future.  If we don't do this, we'd have to add module.h
to obviously non-modular code, and that would be a worse thing.

Note that direct use of __initcall is discouraged, vs.  one of the
priority categorized subgroups.  As __initcall gets mapped onto
device_initcall, our use of fs_initcall (which makes sense for fs code)
will thus change this registration from level 6-device to level 5-fs
(i.e. slightly earlier).  However no observable impact of that small
difference has been observed during testing, or is expected.

Also note that this change uncovers a missing semicolon bug in the
registration of the initcall.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Vladimir Davydov b5bd856a0c fs/super.c: fix WARN on alloc_super() fail path
On fail path alloc_super() calls destroy_super(), which issues a warning
if the sb's s_mounts list is not empty, in particular if it has not been
initialized.  That said s_mounts must be initialized in alloc_super()
before any possible failure, but currently it is initialized close to
the end of the function leading to a useless warning dumped to log if
either percpu_counter_init() or list_lru_init() fails.  Let's fix this.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Corey Minyard 4e4f9e66a7 fs/read_write.c:compat_readv(): remove bogus area verify
The compat_do_readv_writev() function was doing a verify_area on the
incoming iov, but the nr_segs value is not checked.  If someone passes
in a -1 for nr_segs, for instance, the function should return an EINVAL.
However, it returns a EFAULT because the verify_area fails because it is
checking an array of size MAX_UINT.  The check is bogus, anyway, because
the next check, compat_rw_copy_check_uvector(), will do all the
necessary checking, anyway.  The non-compat do_readv_writev() function
doesn't do this check, so I think it's safe to just remove the code.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Dan Carpenter 38316c8ab7 fs/compat_ioctl.c: fix an underflow issue (harmless)
We cap "nmsgs" at I2C_RDRW_IOCTL_MAX_MSGS (42) but the current code
allows negative values.  It's harmless but it makes my static checker
upset so I've made nsmgs unsigned.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Andrew Morton 0afaa12047 posix_acl: uninlining
Uninline vast tracts of nested inline functions in
include/linux/posix_acl.h.

This reduces the text+data+bss size of x86_64 allyesconfig vmlinux by
8026 bytes.

The patch also regularises the positioning of the EXPORT_SYMBOLs in
posix_acl.c.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Benny Halevy <bhalevy@primarydata.com>
Cc: Benny Halevy <bhalevy@panasas.com>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Yiwen Jiang 75f82eaa50 ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously
2 nodes cluster, say Node A and Node B, mount the same ocfs2 volume, and
create a file 1.

Node A			Node B
open 1, get open lock
                        rm 1, and then add 1 to orphan_dir
storage link down,
o2hb_write_timeout
->o2quo_disk_timeout
->emergency_restart
                        at the moment, Node B dismount and do
			ocfs2rec simultaneously
                        1) ocfs2_dismount_volume
			->ocfs2_recovery_exit
			->wait_event(osb->recovery_event)
			->flush_workqueue(ocfs2_wq)
			2) ocfs2rec
			->queue_work(&journal->j_recovery_work)
                        ->ocfs2_recover_orphans
			->ocfs2_commit_truncate
                        ->queue_delayed_work(&osb->osb_truncate_log_wq)

In ocfs2_recovery_exit, it flushes workqueue and then releases system
inodes.  When doing ocfs2rec, it will call ocfs2_flush_truncate_log
which will try to get sys_root_inode, and NULL pointer dereference
occurs.

Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: joyce <xuejiufei@huawei.com>
Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Tariq Saeed a2a3b39824 ocfs2: punch hole should return EINVAL if the length argument in ioctl is negative
An unreserve space ioctl OCFS2_IOC_UNRESVSP/64 should reject a negative
length.

Orabug:14789508

Signed-off-by: Tariq Saseed <tariq.x.saeed@oracle.com>
Signed-off-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Wei Yongjun 16eac4be46 ocfs2: fix sparse non static symbol warning
Fixes the following sparse warning:

  fs/ocfs2/stack_user.c:930:32: warning:
   symbol 'ocfs2_ls_ops' was not declared. Should it be static?

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Jie Liu 1ba2212bb3 ocfs2: adjust minlen with discard_granularity in the FITRIM ioctl
Adjust minlen with discard_granularity for FITRIM ioctl(2) if the given
minimum size in bytes is less than it because, discard granularity is
used to tell us that the minimum size of extent that can be discarded by
the storage device.

This is inspired by ext4 commit 5c2ed62fd4 ("ext4: Adjust minlen with
discard_granularity in the FITRIM ioctl") from Lukas Czerner.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Jie Liu aa89762c54 ocfs2: return EINVAL if the given range to discard is less than block size
For FITRIM ioctl(2), we should not keep silence if the given range
length ls less than a block size as there is no data blocks would be
discareded.  Hence it should return EINVAL instead.  This issue can be
verified via xfstests/generic/288 which is used for FITRIM argument
handling tests.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Jie Liu 19e8ac2721 ocfs2: return EOPNOTSUPP if the device does not support discard
For FITRIM ioctl(2), we should return EOPNOTSUPP to inform the user that
the storage device does not support discard if it is, otherwise return
success would confuse the user even though there is no free blocks were
trimmed at all.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Younger Liu 0a2fcd8988 ocfs2: remove redundant ocfs2_alloc_dinode_update_counts() and ocfs2_block_group_set_bits()
ocfs2_alloc_dinode_update_counts() and ocfs2_block_group_set_bits() are
already provided in suballoc.c.  So, the same functions in
move_extents.c are not needed any more.

Declare the functions in suballoc.h and remove redundant functions in
move_extents.c.

Signed-off-by: Younger Liu <liuyiyang@hisense.com>
Cc: Younger Liu <younger.liucn@gmail.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Goldwyn Rodrigues c994c2ebdb ocfs2: use the new DLM operation callbacks while requesting new lockspace
Attempt to use the new DLM operations.  If it is not supported, use the
traditional ocfs2_controld.

To exchange ocfs2 versioning, we use the LVB of the version dlm lock.
It first attempts to take the lock in EX mode (non-blocking).  If
successful (which means it is the first mount), it writes the version
number and downconverts to PR lock.  If it is unsuccessful, it reads the
version from the lock.

If this becomes the standard (with o2cb as well), it could simplify
userspace tools to check if the filesystem is mounted on other nodes.

Dan: Since ocfs2_protocol_version are two u8 values, the additional
checks with LONG* don't make sense.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:42 -08:00
Goldwyn Rodrigues 4150363033 ocfs2: framework for version LVB
Use the native DLM locks for version control negotiation.  Most of the
framework is taken from gfs2/lock_dlm.c

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Goldwyn Rodrigues 3e83415164 ocfs2: pass ocfs2_cluster_connection to ocfs2_this_node
This is done to differentiate between using and not using controld and
use the connection information accordingly.

We need to be backward compatible.  So, we use a new enum
ocfs2_connection_type to identify when controld is used and when it is
not.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Goldwyn Rodrigues 24aa338611 ocfs2: shift allocation ocfs2_live_connection to user_connect()
We perform this because the DLM recovery callbacks will require the
ocfs2_live_connection structure to record the node information when
dlm_new_lockspace() is updated (in the last patch of the series).

Before calling dlm_new_lockspace(), we need the structure ready for the
.recover_done() callback, which would set oc_this_node.  This is the
reason we allocate ocfs2_live_connection beforehand in user_connect().

[AKPM] rc initialization is not required because it assigned in case of
errors.  It will be cleared by compiler anyways.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reveiwed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Goldwyn Rodrigues 66e188fc31 ocfs2: add DLM recovery callbacks
These are the callbacks called by the fs/dlm code in case the membership
changes.  If there is a failure while/during calling any of these, the
DLM creates a new membership and relays to the rest of the nodes.

 - recover_prep() is called when DLM understands a node is down.
 - recover_slot() is called once all nodes have acknowledged
   recover_prep and recovery can begin.
 - recover_done() is called once the recovery is complete.  It returns
   the new membership.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Goldwyn Rodrigues c74a3bdd9b ocfs2: add clustername to cluster connection
This is an effort of removing ocfs2_controld.pcmk and getting ocfs2 DLM
handling up to the times with respect to DLM (>=4.0.1) and corosync
(2.3.x).  AFAIK, cman also is being phased out for a unified corosync
cluster stack.

fs/dlm performs all the functions with respect to fencing and node
management and provides the API's to do so for ocfs2.  For all future
references, DLM stands for fs/dlm code.

The advantages are:
 + No need to run an additional userspace daemon (ocfs2_controld)
 + No controld device handling and controld protocol
 + Shifting responsibilities of node management to DLM layer

For backward compatibility, we are keeping the controld handling code.
Once enough time has passed we can remove a significant portion of the
code.  This was tested by using the kernel with changes on older
unmodified tools.  The kernel used ocfs2_controld as expected, and
displayed the appropriate warning message.

This feature requires modification in the userspace ocfs2-tools.  The
changes can be found at: https://github.com/goldwynr/ocfs2-tools branch:
nocontrold Currently, not many checks are present in the userspace code,
but that would change soon.

This patch (of 6):

Add clustername to cluster connection.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Goldwyn Rodrigues ff8fb33522 ocfs2: remove versioning information
The versioning information is confusing for end-users.  The numbers are
stuck at 1.5.0 when the tools version have moved to 1.8.2.  Remove the
versioning system in the OCFS2 modules and let the kernel version be the
guide to debug issues.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Acked-by: Sunil Mushran <sunil.mushran@gmail.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara 56b27cf603 fsnotify: remove pointless NULL initializers
We usually rely on the fact that struct members not specified in the
initializer are set to NULL.  So do that with fsnotify function pointers
as well.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara 83c4c4b0a3 fsnotify: remove .should_send_event callback
After removing event structure creation from the generic layer there is
no reason for separate .should_send_event and .handle_event callbacks.
So just remove the first one.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara 7053aee26a fsnotify: do not share events between notification groups
Currently fsnotify framework creates one event structure for each
notification event and links this event into all interested notification
groups.  This is done so that we save memory when several notification
groups are interested in the event.  However the need for event
structure shared between inotify & fanotify bloats the event structure
so the result is often higher memory consumption.

Another problem is that fsnotify framework keeps path references with
outstanding events so that fanotify can return open file descriptors
with its events.  This has the undesirable effect that filesystem cannot
be unmounted while there are outstanding events - a regression for
inotify compared to a situation before it was converted to fsnotify
framework.  For fanotify this problem is hard to avoid and users of
fanotify should kind of expect this behavior when they ask for file
descriptors from notified files.

This patch changes fsnotify and its users to create separate event
structure for each group.  This allows for much simpler code (~400 lines
removed by this patch) and also smaller event structures.  For example
on 64-bit system original struct fsnotify_event consumes 120 bytes, plus
additional space for file name, additional 24 bytes for second and each
subsequent group linking the event, and additional 32 bytes for each
inotify group for private data.  After the conversion inotify event
consumes 48 bytes plus space for file name which is considerably less
memory unless file names are long and there are several groups
interested in the events (both of which are uncommon).  Fanotify event
fits in 56 bytes after the conversion (fanotify doesn't care about file
names so its events don't have to have it allocated).  A win unless
there are four or more fanotify groups interested in the event.

The conversion also solves the problem with unmount when only inotify is
used as we don't have to grab path references for inotify events.

[hughd@google.com: fanotify: fix corruption preventing startup]
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Jan Kara e9fe69045b inotify: provide function for name length rounding
Rounding of name length when passing it to userspace was done in several
places.  Provide a function to do it and use it in all places.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-21 16:19:41 -08:00
Linus Torvalds d3bad75a6d Driver core / sysfs patches for 3.14-rc1
Here's the big driver core and sysfs patch set for 3.14-rc1.
 
 There's a lot of work here moving sysfs logic out into a "kernfs" to
 allow other subsystems to also have a virtual filesystem with the same
 attributes of sysfs (handle device disconnect, dynamic creation /
 removal  as needed / unneeded, etc.  This is primarily being done for
 the cgroups filesystem, but the goal is to also move debugfs to it when
 it is ready, solving all of the known issues in that filesystem as well.
 The code isn't completed yet, but all should be stable now (there is a
 big section that was reverted due to problems found when testing.)
 
 There's also some other smaller fixes, and a driver core addition that
 allows for a "collection" of objects, that the DRM people will be using
 soon (it's in this tree to make merges after -rc1 easier.)
 
 All of this has been in linux-next with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core / sysfs patches from Greg KH:
 "Here's the big driver core and sysfs patch set for 3.14-rc1.

  There's a lot of work here moving sysfs logic out into a "kernfs" to
  allow other subsystems to also have a virtual filesystem with the same
  attributes of sysfs (handle device disconnect, dynamic creation /
  removal as needed / unneeded, etc)

  This is primarily being done for the cgroups filesystem, but the goal
  is to also move debugfs to it when it is ready, solving all of the
  known issues in that filesystem as well.  The code isn't completed
  yet, but all should be stable now (there is a big section that was
  reverted due to problems found when testing)

  There's also some other smaller fixes, and a driver core addition that
  allows for a "collection" of objects, that the DRM people will be
  using soon (it's in this tree to make merges after -rc1 easier)

  All of this has been in linux-next with no reported issues"

* tag 'driver-core-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (113 commits)
  kernfs: associate a new kernfs_node with its parent on creation
  kernfs: add struct dentry declaration in kernfs.h
  kernfs: fix get_active failure handling in kernfs_seq_*()
  Revert "kernfs: fix get_active failure handling in kernfs_seq_*()"
  Revert "kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitq"
  Revert "kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()"
  Revert "kernfs: remove KERNFS_REMOVED"
  Revert "kernfs: restructure removal path to fix possible premature return"
  Revert "kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()"
  Revert "kernfs: remove kernfs_addrm_cxt"
  Revert "kernfs: make kernfs_get_active() block if the node is deactivated but not removed"
  Revert "kernfs: implement kernfs_{de|re}activate[_self]()"
  Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers"
  Revert "pci: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "scsi: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "s390: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()"
  Revert "kernfs: remove unnecessary NULL check in __kernfs_remove()"
  kernfs: remove unnecessary NULL check in __kernfs_remove()
  drivers/base: provide an infrastructure for componentised subsystems
  ...
2014-01-20 15:49:44 -08:00
Linus Torvalds 48ba620aab Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace fixes from Eric Biederman:
 "This is a set of 3 regression fixes.

  This fixes /proc/mounts when using "ip netns add <netns>" to display
  the actual mount point.

  This fixes a regression in clone that broke lxc-attach.

  This fixes a regression in the permission checks for mounting /proc
  that made proc unmountable if binfmt_misc was in use.  Oops.

  My apologies for sending this pull request so late.  Al Viro gave
  interesting review comments about the d_path fix that I wanted to
  address in detail before I sent this pull request.  Unfortunately a
  bad round of colds kept from addressing that in detail until today.
  The executive summary of the review was:

  Al: Is patching d_path really sufficient?
      The prepend_path, d_path, d_absolute_path, and __d_path family of
      functions is a really mess.

  Me: Yes, patching d_path is really sufficient.  Yes, the code is mess.
      No it is not appropriate to rewrite all of d_path for a regression
      that has existed for entirely too long already, when a two line
      change will do"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  vfs: Fix a regression in mounting proc
  fork:  Allow CLONE_PARENT after setns(CLONE_NEWPID)
  vfs: In d_path don't call d_dname on a mount point
2014-01-17 17:29:36 -08:00
Tejun Heo db4aad209b kernfs: associate a new kernfs_node with its parent on creation
Once created, a kernfs_node is always destroyed by kernfs_put().
Since ba7443bc65 ("sysfs, kernfs: implement
kernfs_create/destroy_root()"), kernfs_put() depends on kernfs_root()
to locate the ino_ida.  kernfs_root() in turn depends on
kernfs_node->parent being set for !dir nodes.  This means that
kernfs_put() of a !dir node requires its ->parent to be initialized.

This leads to oops when a newly created !dir node is destroyed without
going through kernfs_add_one() or after failing kernfs_add_one()
before ->parent is set.  kernfs_root() invoked from kernfs_put() will
try to dereference NULL parent.

Fix it by moving parent association to kernfs_new_node() from
kernfs_add_one().  kernfs_new_node() now takes @parent instead of
@root and determines the root from the parent and also sets the new
node's parent properly.  @parent parameter is removed from
kernfs_add_one().  As there's no parent when creating the root node,
__kernfs_new_node() which takes @root as before and doesn't set the
parent is used in that case.

This ensures that a kernfs_node in any stage in its life has its
parent associated and thus can be put.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-17 11:50:07 -08:00
Linus Torvalds 70b23ce347 fix data corruption on NFS writeback
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Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

Pull writeback fix from Wu Fengguang:
 "Fix data corruption on NFS writeback.

  It has been in linux-next for one month"

* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  writeback: Fix data corruption on NFS
2014-01-16 08:23:34 +07:00
Andreas Rohner 70f2fe3a26 nilfs2: fix segctor bug that causes file system corruption
There is a bug in the function nilfs_segctor_collect, which results in
active data being written to a segment, that is marked as clean.  It is
possible, that this segment is selected for a later segment
construction, whereby the old data is overwritten.

The problem shows itself with the following kernel log message:

  nilfs_sufile_do_cancel_free: segment 6533 must be clean

Usually a few hours later the file system gets corrupted:

  NILFS: bad btree node (blocknr=8748107): level = 0, flags = 0x0, nchildren = 0
  NILFS error (device sdc1): nilfs_bmap_last_key: broken bmap (inode number=114660)

The issue can be reproduced with a file system that is nearly full and
with the cleaner running, while some IO intensive task is running.
Although it is quite hard to reproduce.

This is what happens:

 1. The cleaner starts the segment construction
 2. nilfs_segctor_collect is called
 3. sc_stage is on NILFS_ST_SUFILE and segments are freed
 4. sc_stage is on NILFS_ST_DAT current segment is full
 5. nilfs_segctor_extend_segments is called, which
    allocates a new segment
 6. The new segment is one of the segments freed in step 3
 7. nilfs_sufile_cancel_freev is called and produces an error message
 8. Loop around and the collection starts again
 9. sc_stage is on NILFS_ST_SUFILE and segments are freed
    including the newly allocated segment, which will contain active
    data and can be allocated at a later time
10. A few hours later another segment construction allocates the
    segment and causes file system corruption

This can be prevented by simply reordering the statements.  If
nilfs_sufile_cancel_freev is called before nilfs_segctor_extend_segments
the freed segments are marked as dirty and cannot be allocated any more.

Signed-off-by: Andreas Rohner <andreas.rohner@gmx.net>
Reviewed-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Andreas Rohner <andreas.rohner@gmx.net>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-15 14:19:42 +07:00
Tejun Heo bb305947bd kernfs: fix get_active failure handling in kernfs_seq_*()
When kernfs_seq_start() fails to obtain an active reference, it
returns ERR_PTR(-ENODEV).  kernfs_seq_stop() is then invoked with the
error pointer value; however, it still proceeds to invoke
kernfs_put_active() on the node leading to unbalanced put.

If kernfs_seq_stop() is called even after active ref failure, it
should skip invocation of @ops->seq_stop() and put_active.
Unfortunately, this is a bit complicated because active ref failure
isn't the only thing which may fail with ERR_PTR(-ENODEV).
@ops->seq_start/next() may also fail with the error value and
kernfs_seq_stop() doesn't have a way to tell apart those failures.

Work it around by factoring out the active part of kernfs_seq_stop()
into kernfs_seq_stop_active() and invoking it directly if
@ops->seq_start/next() fail with ERR_PTR(-ENODEV) and updating
kernfs_seq_stop() to skip kernfs_seq_stop_active() on
ERR_PTR(-ENODEV).  This is a bit nasty but ensures that the active put
is skipped iff get_active failed in kernfs_seq_start().

tj: This was originally committed as d92d2e6bd7 but got reverted by
    683bb2761f along with other kernfs self removal patches.
    However, this one is an independent fix and shouldn't have been
    reverted together.  Reinstate the change.  Sorry about the mess.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-14 08:49:22 -08:00
Greg Kroah-Hartman 683bb2761f Revert "kernfs: fix get_active failure handling in kernfs_seq_*()"
This reverts commit d92d2e6bd7.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:49:01 -08:00
Greg Kroah-Hartman 87da149343 Revert "kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitq"
This reverts commit ea1c472dfe.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:43:11 -08:00
Greg Kroah-Hartman 0890147fe0 Revert "kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()"
This reverts commit a69d001cfc.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:39:52 -08:00
Greg Kroah-Hartman 798c75a0d4 Revert "kernfs: remove KERNFS_REMOVED"
This reverts commit ae34372eb8.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:36:03 -08:00
Greg Kroah-Hartman 4f4b1b6471 Revert "kernfs: restructure removal path to fix possible premature return"
This reverts commit 45a140e587.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:30:47 -08:00
Greg Kroah-Hartman 55f6e30d0a Revert "kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()"
This reverts commit f601f9a2bf.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:27:16 -08:00
Greg Kroah-Hartman 7653fe9d6c Revert "kernfs: remove kernfs_addrm_cxt"
This reverts commit 99177a3411.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:20:56 -08:00
Greg Kroah-Hartman f4b3e631b3 Revert "kernfs: make kernfs_get_active() block if the node is deactivated but not removed"
This reverts commit 895a068a52.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:13:39 -08:00
Greg Kroah-Hartman 9b0925a6ff Revert "kernfs: implement kernfs_{de|re}activate[_self]()"
This reverts commit 9f010c2ad5.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:09:38 -08:00
Greg Kroah-Hartman a9f138b0e5 Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers"
This reverts commit 1ae06819c7.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 14:05:13 -08:00
Greg Kroah-Hartman a30f82b7eb Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()"
This reverts commit d1ba277e79.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 13:51:36 -08:00
Greg Kroah-Hartman ce9b499c9f Revert "kernfs: remove unnecessary NULL check in __kernfs_remove()"
This reverts commit 88533f990c.

Tejun writes:
        I'm sorry but can you please revert the whole series?
        get_active() waiting while a node is deactivated has potential
        to lead to deadlock and that deactivate/reactivate interface is
        something fundamentally flawed and that cgroup will have to work
        with the remove_self() like everybody else.  IOW, I think the
        first posting was correct.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-13 13:50:31 -08:00
Tejun Heo 88533f990c kernfs: remove unnecessary NULL check in __kernfs_remove()
895a068a52 ("kernfs: make kernfs_get_active() block if the node is
deactivated but not removed") added "struct kernfs_root *root =
kernfs_root(kn);" at the head of the function; however, the parameter
@kn is checked for later implying that the function may be called with
NULL.  This means that we may end up invoking kernfs_root() with NULL
which will oops.  None of the existing users invokes removal with NULL
@kn, so this bug doesn't actually trigger.

We can relocate kernfs_root() invocation after NULL check; however,
allowing NULL param tends to cause more confusion than actually
helping anything.  As there's no existing user, let's remove the
spurious NULL check.

This bug was detected by smatch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-11 15:40:19 -08:00
Tejun Heo d1ba277e79 sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()
All device_schedule_callback_owner() users are converted to use
device_remove_file_self().  Remove now unused
{sysfs|device}_schedule_callback_owner().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 16:03:19 -08:00
Linus Torvalds e2bc44706f xfs: bugfixes for 3.13-rc8
- fix off-by-one in xfs_attr3_rmt_verify
 - fix missing destroy_work_on_stack() in xfs_bmapi_allocate
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Merge tag 'xfs-for-linus-v3.13-rc8' of git://oss.sgi.com/xfs/xfs

Pull xfs bugfixes from Ben Myers:
 "Here we have a bugfix for an off-by-one in the remote attribute
  verifier that results in a forced shutdown which you can hit with v5
  superblock by creating a 64k xattr, and a fix for a missing
  destroy_work_on_stack() in the allocation worker.

  It's a bit late, but they are both fairly straightforward"

* tag 'xfs-for-linus-v3.13-rc8' of git://oss.sgi.com/xfs/xfs:
  xfs: Calling destroy_work_on_stack() to pair with INIT_WORK_ONSTACK()
  xfs: fix off-by-one error in xfs_attr3_rmt_verify
2014-01-11 06:33:03 +07:00
Tejun Heo 1ae06819c7 kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers
Sometimes it's necessary to implement a node which wants to delete
nodes including itself.  This isn't straightforward because of kernfs
active reference.  While a file operation is in progress, an active
reference is held and kernfs_remove() waits for all such references to
drain before completing.  For a self-deleting node, this is a deadlock
as kernfs_remove() ends up waiting for an active reference that itself
is sitting on top of.

This currently is worked around in the sysfs layer using
sysfs_schedule_callback() which makes such removals asynchronous.
While it works, it's rather cumbersome and inherently breaks
synchronicity of the operation - the file operation which triggered
the operation may complete before the removal is finished (or even
started) and the removal may fail asynchronously.  If a removal
operation is immmediately followed by another operation which expects
the specific name to be available (e.g. removal followed by rename
onto the same name), there's no way to make the latter operation
reliable.

The thing is there's no inherent reason for this to be asynchrnous.
All that's necessary to do this synchronous is a dedicated operation
which drops its own active ref and deactivates self.  This patch
implements kernfs_remove_self() and its wrappers in sysfs and driver
core.  kernfs_remove_self() is to be called from one of the file
operations, drops the active ref and deactivates using
__kernfs_deactivate_self(), removes the self node, and restores active
ref to the dead node using __kernfs_reactivate_self() so that the ref
is balanced afterwards.  __kernfs_remove() is updated so that it takes
an early exit if the target node is already fully removed so that the
active ref restored by kernfs_remove_self() after removal doesn't
confuse the deactivation path.

This makes implementing self-deleting nodes very easy.  The normal
removal path doesn't even need to be changed to use
kernfs_remove_self() for the self-deleting node.  The method can
invoke kernfs_remove_self() on itself before proceeding the normal
removal path.  kernfs_remove() invoked on the node by the normal
deletion path will simply be ignored.

This will replace sysfs_schedule_callback().  A subtle feature of
sysfs_schedule_callback() is that it collapses multiple invocations -
even if multiple removals are triggered, the removal callback is run
only once.  An equivalent effect can be achieved by testing the return
value of kernfs_remove_self() - only the one which gets %true return
value should proceed with actual deletion.  All other instances of
kernfs_remove_self() will wait till the enclosing kernfs operation
which invoked the winning instance of kernfs_remove_self() finishes
and then return %false.  This trivially makes all users of
kernfs_remove_self() automatically show correct synchronous behavior
even when there are multiple concurrent operations - all "echo 1 >
delete" instances will finish only after the whole operation is
completed by one of the instances.

v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing
    and sysfs_remove_file_self() had incorrect return type.  Fix it.
    Reported by kbuild test bot.

v3: Updated to use __kernfs_{de|re}activate_self().

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 14:01:05 -08:00
Tejun Heo 9f010c2ad5 kernfs: implement kernfs_{de|re}activate[_self]()
This patch implements four functions to manipulate deactivation state
- deactivate, reactivate and the _self suffixed pair.  A new fields
kernfs_node->deact_depth is added so that concurrent and nested
deactivations are handled properly.  kernfs_node->hash is moved so
that it's paired with the new field so that it doesn't increase the
size of kernfs_node.

A kernfs user's lock would normally nest inside active ref but during
removal the user may want to perform kernfs_remove() while holding the
said lock, which would introduce a reverse locking dependency.  This
function can be used to break such reverse dependency by allowing
deactivation step to performed separately outside user's critical
section.

This will also be used implement kernfs_remove_self().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:51:21 -08:00
Tejun Heo 895a068a52 kernfs: make kernfs_get_active() block if the node is deactivated but not removed
Currently, kernfs_get_active() fails if the target node is
deactivated.  This is fine as a node always gets removed after
deactivation; however, we're gonna add reactivation so the assumption
won't hold.  It'd be incorrect for kernfs_get_active() to fail for a
node which was deactivated only temporarily.

This patch makes kernfs_get_active() block if the node is deactivated
but not removed.  If the node gets reactivated (not yet implemented),
it will be retried and succeed.  If the node gets removed, it will be
woken up and fail.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:48:08 -08:00
Tejun Heo 99177a3411 kernfs: remove kernfs_addrm_cxt
kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were
added because there were operations which should be performed outside
kernfs_mutex after adding and removing kernfs_nodes.  The necessary
operations were recorded in kernfs_addrm_cxt and performed by
kernfs_addrm_finish(); however, after the recent changes which
relocated deactivation and unmapping so that they're performed
directly during removal, the only operation kernfs_addrm_finish()
performs is kernfs_put(), which can be moved inside the removal path
too.

This patch moves the kernfs_put() of the base ref to __kernfs_remove()
and remove kernfs_addrm_cxt and kernfs_addrm_start/finish().

* kernfs_add_one() is updated to grab and release the parent's active
  ref and kernfs_mutex itself.  kernfs_get/put_active() and
  kernfs_addrm_start/finish() invocations around it are removed from
  all users.

* __kernfs_remove() puts an unlinked node directly instead of chaining
  it to kernfs_addrm_cxt.  Its callers are updated to grab and release
  kernfs_mutex instead of calling kernfs_addrm_start/finish() around
  it.

v2: Updated to fit the v2 restructuring of removal path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:48:08 -08:00
Tejun Heo f601f9a2bf kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()
kernfs_unmap_bin_file() is supposed to unmap all memory mappings of
the target file before kernfs_remove() finishes; however, it currently
is being called from kernfs_addrm_finish() and has the same race
problem as the original implementation of deactivation when there are
multiple removers - only the remover which snatches the node to its
addrm_cxt->removed list is guaranteed to wait for its completion
before returning.

It can be fixed by moving kernfs_unmap_bin_file() invocation from
kernfs_addrm_finish() to __kernfs_remove().  The function may be
called multiple times but that shouldn't do any harm.

We end up dropping kernfs_mutex in the removal loop and the node may
be removed inbetween by someone else.  kernfs_unlink_sibling() is
updated to test whether the node has already been removed and return
accordingly.  __kernfs_remove() in turn performs post-unlinking
cleanup only if it actually unlinked the node.

KERNFS_HAS_MMAP test is moved out of the unmap function into
__kernfs_remove() so that we don't unlock kernfs_mutex unnecessarily.
While at it, drop the now meaningless "bin" qualifier from the
function name.

v2: Rewritten to fit the v2 restructuring of removal path.  HAS_MMAP
    test relocated.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-01-10 13:48:08 -08:00