linux.git/fs/super.c, branch v2.6.28

Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev

2008-10-23T17:23:07+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev: (66 commits)
  [PATCH] kill the rest of struct file propagation in block ioctls
  [PATCH] get rid of struct file use in blkdev_ioctl() BLKBSZSET
  [PATCH] get rid of blkdev_locked_ioctl()
  [PATCH] get rid of blkdev_driver_ioctl()
  [PATCH] sanitize blkdev_get() and friends
  [PATCH] remember mode of reiserfs journal
  [PATCH] propagate mode through swsusp_close()
  [PATCH] propagate mode through open_bdev_excl/close_bdev_excl
  [PATCH] pass fmode_t to blkdev_put()
  [PATCH] kill the unused bsize on the send side of /dev/loop
  [PATCH] trim file propagation in block/compat_ioctl.c
  [PATCH] end of methods switch: remove the old ones
  [PATCH] switch sr
  [PATCH] switch sd
  [PATCH] switch ide-scsi
  [PATCH] switch tape_block
  [PATCH] switch dcssblk
  [PATCH] switch dasd
  [PATCH] switch mtd_blkdevs
  [PATCH] switch mmc
  ...

[PATCH 2/2] anondev: switch to IDA

2008-10-23T09:13:14+00:00

Signed-off-by: Alexey Dobriyan

[PATCH 1/2] anondev: init IDR statically

2008-10-23T09:13:13+00:00

Signed-off-by: Alexey Dobriyan

[PATCH] propagate mode through open_bdev_excl/close_bdev_excl

2008-10-21T11:49:00+00:00

replace open_bdev_excl/close_bdev_excl with variants taking fmode_t.
superblock gets the value used to mount it stored in sb->s_mode

Signed-off-by: Al Viro

fix soft lock up at NFS mount via per-SB LRU-list of unused dentries

2008-07-24T17:47:15+00:00

[Summary]

 Split LRU-list of unused dentries to one per superblock to avoid soft
 lock up during NFS mounts and remounting of any filesystem.

 Previously I posted here:
 http://lkml.org/lkml/2008/3/5/590

[Descriptions]

- background

  dentry_unused is a list of dentries which are not referenced.
  dentry_unused grows up when references on directories or files are
  released.  This list can be very long if there is huge free memory.

- the problem

  When shrink_dcache_sb() is called, it scans all dentry_unused linearly
  under spin_lock(), and if dentry->d_sb is differnt from given
  superblock, scan next dentry.  This scan costs very much if there are
  many entries, and very ineffective if there are many superblocks.

  IOW, When we need to shrink unused dentries on one dentry, but scans
  unused dentries on all superblocks in the system.  For example, we scan
  500 dentries to unmount a filesystem, but scans 1,000,000 or more unused
  dentries on other superblocks.

  In our case , At mounting NFS*, shrink_dcache_sb() is called to shrink
  unused dentries on NFS, but scans 100,000,000 unused dentries on
  superblocks in the system such as local ext3 filesystems.  I hear NFS
  mounting took 1 min on some system in use.

* : NFS uses virtual filesystem in rpc layer, so NFS is affected by
  this problem.

  100,000,000 is possible number on large systems.

  Per-superblock LRU of unused dentried can reduce the cost in
  reasonable manner.

- How to fix

  I found this problem is solved by David Chinner's "Per-superblock
  unused dentry LRU lists V3"(1), so I rebase it and add some fix to
  reclaim with fairness, which is in Andrew Morton's comments(2).

  1) http://lkml.org/lkml/2006/5/25/318
  2) http://lkml.org/lkml/2006/5/25/320

  Split LRU-list of unused dentries to each superblocks.  Then, NFS
  mounting will check dentries under a superblock instead of all.  But
  this spliting will break LRU of dentry-unused.  So, I've attempted to
  make reclaim unused dentrins with fairness by calculate number of
  dentries to scan on this sb based on following way

  number of dentries to scan on this sb =
  count * (number of dentries on this sb / number of dentries in the machine)

- ToDo
 - I have to measuring performance number and do stress tests.

 - When unmount occurs during prune_dcache(), scanning on same
  superblock, It is unable to reach next superblock because it is gone
  away.  We restart scannig superblock from first one, it causes
  unfairness of reclaim unused dentries on first superblock.  But I think
  this happens very rarely.

- Test Results

  Result on 6GB boxes with excessive unused dentries.

Without patch:

$ cat /proc/sys/fs/dentry-state
10181835        10180203        45      0       0       0
# mount -t nfs 10.124.60.70:/work/kernel-src nfs
real    0m1.830s
user    0m0.001s
sys     0m1.653s

 With this patch:
$ cat /proc/sys/fs/dentry-state
10236610        10234751        45      0       0       0
# mount -t nfs 10.124.60.70:/work/kernel-src nfs
real    0m0.106s
user    0m0.002s
sys     0m0.032s

[akpm@linux-foundation.org: fix comments]
Signed-off-by: Kentaro Makita 
Cc: Neil Brown 
Cc: Trond Myklebust 
Cc: David Chinner 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

make __put_super() static

2008-04-29T15:06:00+00:00

Make the needlessly global __put_super() static.

Signed-off-by: Adrian Bunk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

quota: quota core changes for quotaon on remount

2008-04-28T15:58:33+00:00

Currently, we just turn quotas off on remount of filesystem to read-only
state.  The patch below adds necessary framework so that we can turn quotas
off on remount RO but we are able to automatically reenable them again when
filesystem is remounted to RW state.  All we need to do is to keep references
to inodes of quota files when remounting RO and using these references to
reenable quotas when remounting RW.

Signed-off-by: Jan Kara 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] move a bunch of declarations to fs/internal.h

2008-04-22T03:11:01+00:00

Signed-off-by: Al Viro

[PATCH] r/o bind mounts: debugging for missed calls

2008-04-19T04:29:28+00:00

There have been a few oopses caused by 'struct file's with NULL f_vfsmnts.
There was also a set of potentially missed mnt_want_write()s from
dentry_open() calls.

This patch provides a very simple debugging framework to catch these kinds of
bugs.  It will WARN_ON() them, but should stop us from having any oopses or
mnt_writer count imbalances.

I'm quite convinced that this is a good thing because it found bugs in the
stuff I was working on as soon as I wrote it.

[hch: made it conditional on a debug option.
      But it's still a little bit too ugly]

[hch: merged forced remount r/o fix from Dave and akpm's fix for the fix]

Signed-off-by: Dave Hansen 
Acked-by: Al Viro 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro

[PATCH] r/o bind mounts: drop write during emergency remount

2008-04-19T04:25:33+00:00

The emergency remount code forcibly removes FMODE_WRITE from
filps.  The r/o bind mount code notices that this was done
without a proper mnt_drop_write() and properly gives a
warning.

This patch does a mnt_drop_write() to keep everything
balanced.

Acked-by: Al Viro 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Dave Hansen 
Signed-off-by: Al Viro