1
Commit Graph

118 Commits

Author SHA1 Message Date
Al Viro
6754af6464 Convert simple loops over superblocks to list_for_each_entry_safe
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:15 -04:00
Al Viro
8edd64bd60 get rid of restarts in sync_filesystems()
At the same time we can kill s_need_restart and local mutex in there.
__put_super() made public for a while; will be gone later.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:15 -04:00
Al Viro
551de6f34d Leave superblocks on s_list until the end
We used to remove from s_list and s_instances at the same
time.  So let's *not* do the former and skip superblocks
that have empty s_instances in the loops over s_list.

The next step, of course, will be to get rid of rescan logics
in those loops.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:14 -04:00
Al Viro
1712ac8fda Saner locking around deactivate_super()
Make sure that s_umount is acquired *before* we drop the final
active reference; we still have the fast path (atomic_dec_unless)
and we have gotten rid of the window between the moment when
s_active hits zero and s_umount is acquired.  Which simplifies
the living hell out of grab_super() and inotify pin_to_kill()
stuff.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:14 -04:00
Al Viro
b20bd1a5e7 get rid of S_BIAS
use atomic_inc_not_zero(&sb->s_active) instead of playing games with
checking ->s_count > S_BIAS

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:14 -04:00
Al Viro
389b8be6ef get rid of open-coded grab_super() in get_active_super()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:14 -04:00
Christoph Hellwig
a135aa2cd7 remove incorrect comment in do_emergency_remount
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:12 -04:00
Jens Axboe
5477d0face fs: fs/super.c needs to include backing-dev.h for !CONFIG_BLOCK
When CONFIG_BLOCK is set, it ends up getting backing-dev.h included.
But for !CONFIG_BLOCK, it isn't so lucky. The proper thing to do is
include <linux/backing-dev.h> directly from the file it's used from,
so do that.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-29 20:33:35 +02:00
Jörn Engel
5129a469a9 Catch filesystems lacking s_bdi
noop_backing_dev_info is used only as a flag to mark filesystems that
don't have any backing store, like tmpfs, procfs, spufs, etc.

Signed-off-by: Joern Engel <joern@logfs.org>

Changed the BUG_ON() to a WARN_ON(). Note that adding dirty inodes
to the noop_backing_dev_info is not legal and will not result in
them being flushed, but we already catch this condition in
__mark_inode_dirty() when checking for a registered bdi.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-25 08:54:42 +02:00
Al Viro
8089352a13 Mirror MS_KERNMOUNT in ->mnt_flags
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 14:08:00 -05:00
Nick Piggin
d208bbdda9 fs: improve remount,ro vs buffercache coherency
Invalidate sb->s_bdev on remount,ro.

Fixes a problem reported by Jorge Boncompte who is seeing corruption
trying to snapshot a minix filesystem image.  Some filesystems modify
their metadata via a path other than the bdev buffer cache (eg.  they may
use a private linear mapping for their metadata, or implement directories
in pagecache, etc).  Also, file data modifications usually go to the bdev
via their own mappings.

These updates are not coherent with buffercache IO (eg.  via /dev/bdev)
and never have been.  However there could be a reasonable expectation that
after a mount -oremount,ro operation then the buffercache should
subsequently be coherent with previous filesystem modifications.

So invalidate the bdev mappings on a remount,ro operation to provide a
coherency point.

The problem was exposed when we switched the old rd to brd because old rd
didn't really function like a normal block device and updates to rd via
mappings other than the buffercache would still end up going into its
buffercache.  But the same problem has always affected other "normal"
block devices, including loop.

[akpm@linux-foundation.org: repair comment layout]
Reported-by: "Jorge Boncompte [DTI2]" <jorge@dti2.net>
Tested-by: "Jorge Boncompte [DTI2]" <jorge@dti2.net>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-03-03 13:00:20 -05:00
Kay Sievers
9329d1beae vfs: get_sb_single() - do not pass options twice
Filesystem code usually destroys the option buffer while
parsing it. This leads to errors when the same buffer is
passed twice. In case we fill a new superblock do not call
remount.

This is needed to quite a warning that the debugfs code
causes every boot.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-12-23 11:23:43 -08:00
Christoph Hellwig
4504230a71 freeze_bdev: grab active reference to frozen superblocks
Currently we held s_umount while a filesystem is frozen, despite that we
might return to userspace and unlock it from a different process.  Instead
grab an active reference to keep the file system busy and add an explicit
check for frozen filesystems in remount and reject the remount instead
of blocking on s_umount.

Add a new get_active_super helper to super.c for use by freeze_bdev that
grabs an active reference to a superblock from a given block device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-09-24 07:47:41 -04:00
Christoph Hellwig
4fadd7bb20 freeze_bdev: kill bd_mount_sem
Now that we have the freeze count there is not much reason for bd_mount_sem
anymore.  The actual freeze/thaw operations are serialized using the
bd_fsfreeze_mutex, and the only other place we take bd_mount_sem is
get_sb_bdev which tries to prevent mounting a filesystem while the block
device is frozen.  Instead of add a check for bd_fsfreeze_count and
return -EBUSY if a filesystem is frozen.  While that is a change in user
visible behaviour a failing mount is much better for this case rather
than having the mount process stuck uninterruptible for a long time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-09-24 07:47:39 -04:00
Jeff Layton
42cb56ae2a vfs: change sb->s_maxbytes to a loff_t
sb->s_maxbytes is supposed to indicate the maximum size of a file that can
exist on the filesystem.  It's declared as an unsigned long long.

Even if a filesystem has no inherent limit that prevents it from using
every bit in that unsigned long long, it's still problematic to set it to
anything larger than MAX_LFS_FILESIZE.  There are places in the kernel
that cast s_maxbytes to a signed value.  If it's set too large then this
cast makes it a negative number and generally breaks the comparison.

Change s_maxbytes to be loff_t instead.  That should help eliminate the
temptation to set it too large by making it a signed value.

Also, add a warning for couple of releases to help catch filesystems that
set s_maxbytes too large.  Eventually we can either convert this to a
BUG() or just remove it and in the hope that no one will get it wrong now
that it's a signed value.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Robert Love <rlove@google.com>
Cc: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-09-24 07:47:33 -04:00
Alexey Dobriyan
b87221de6a const: mark remaining super_operations const
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:24 -07:00
Jens Axboe
32a88aa1b6 fs: Assign bdi in super_block
We do this automatically in get_sb_bdev() from the set_bdev_super()
callback. Filesystems that have their own private backing_dev_info
must assign that in ->fill_super().

Note that ->s_bdi assignment is required for proper writeback!

Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-16 15:18:51 +02:00
Jens Axboe
03ba3782e8 writeback: switch to per-bdi threads for flushing data
This gets rid of pdflush for bdi writeout and kupdated style cleaning.
pdflush writeout suffers from lack of locality and also requires more
threads to handle the same workload, since it has to work in a
non-blocking fashion against each queue. This also introduces lumpy
behaviour and potential request starvation, since pdflush can be starved
for queue access if others are accessing it. A sample ffsb workload that
does random writes to files is about 8% faster here on a simple SATA drive
during the benchmark phase. File layout also seems a LOT more smooth in
vmstat:

 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
 0  1      0 608848   2652 375372    0    0     0 71024  604    24  1 10 48 42
 0  1      0 549644   2712 433736    0    0     0 60692  505    27  1  8 48 44
 1  0      0 476928   2784 505192    0    0     4 29540  553    24  0  9 53 37
 0  1      0 457972   2808 524008    0    0     0 54876  331    16  0  4 38 58
 0  1      0 366128   2928 614284    0    0     4 92168  710    58  0 13 53 34
 0  1      0 295092   3000 684140    0    0     0 62924  572    23  0  9 53 37
 0  1      0 236592   3064 741704    0    0     4 58256  523    17  0  8 48 44
 0  1      0 165608   3132 811464    0    0     0 57460  560    21  0  8 54 38
 0  1      0 102952   3200 873164    0    0     4 74748  540    29  1 10 48 41
 0  1      0  48604   3252 926472    0    0     0 53248  469    29  0  7 47 45

where vanilla tends to fluctuate a lot in the creation phase:

 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
 1  1      0 678716   5792 303380    0    0     0 74064  565    50  1 11 52 36
 1  0      0 662488   5864 319396    0    0     4   352  302   329  0  2 47 51
 0  1      0 599312   5924 381468    0    0     0 78164  516    55  0  9 51 40
 0  1      0 519952   6008 459516    0    0     4 78156  622    56  1 11 52 37
 1  1      0 436640   6092 541632    0    0     0 82244  622    54  0 11 48 41
 0  1      0 436640   6092 541660    0    0     0     8  152    39  0  0 51 49
 0  1      0 332224   6200 644252    0    0     4 102800  728    46  1 13 49 36
 1  0      0 274492   6260 701056    0    0     4 12328  459    49  0  7 50 43
 0  1      0 211220   6324 763356    0    0     0 106940  515    37  1 10 51 39
 1  0      0 160412   6376 813468    0    0     0  8224  415    43  0  6 49 45
 1  1      0  85980   6452 886556    0    0     4 113516  575    39  1 11 54 34
 0  2      0  85968   6452 886620    0    0     0  1640  158   211  0  0 46 54

A 10 disk test with btrfs performs 26% faster with per-bdi flushing. A
SSD based writeback test on XFS performs over 20% better as well, with
the throughput being very stable around 1GB/sec, where pdflush only
manages 750MB/sec and fluctuates wildly while doing so. Random buffered
writes to many files behave a lot better as well, as does random mmap'ed
writes.

A separate thread is added to sync the super blocks. In the long term,
adding sync_supers_bdi() functionality could get rid of this thread again.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 09:20:25 +02:00
Jens Axboe
66f3b8e2e1 writeback: move dirty inodes from super_block to backing_dev_info
This is a first step at introducing per-bdi flusher threads. We should
have no change in behaviour, although sb_has_dirty_inodes() is now
ridiculously expensive, as there's no easy way to answer that question.
Not a huge problem, since it'll be deleted in subsequent patches.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 09:20:25 +02:00
Al Viro
f21f62208a ... and the same for vfsmount id/mount group id
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 08:15:26 -04:00
Al Viro
c63e09eccc Make allocation of anon devices cheaper
Standard trick - add a new variable (start) such that
for each n < start n is known to be busy.  Allocation can
skip checking everything in [0..start) and if it returns
n, we can set start to n + 1.  Freeing below start sets
start to what we'd just freed.

Of course, it still sucks if we do something like
	free 0
	allocate
	allocate
in a loop - still O(n^2) time.  However, on saner loads it
improves the things a lot and the entire thing is not worth
the trouble of switching to something with better worst-case
behaviour.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 08:15:25 -04:00
J. R. Okajima
b0895513f4 remove unlock_kernel() left accidentally
commit 337eb00a2c
Push BKL down into ->remount_fs()
and
commit 4aa98cf768
Push BKL down into do_remount_sb()

were uncorrectly merged.
The former removes one pair of lock/unlock_kernel(), but the latter adds
several unlock_kernel(). Finally a few unlock_kernel() calls left.

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-17 00:36:35 -04:00
Alessio Igor Bogani
337eb00a2c Push BKL down into ->remount_fs()
[xfs, btrfs, capifs, shmem don't need BKL, exempt]

Signed-off-by: Alessio Igor Bogani <abogani@texware.it>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:11 -04:00
Christoph Hellwig
ebc1ac1645 ->write_super lock_super pushdown
Push down lock_super into ->write_super instances and remove it from the
caller.

Following filesystem don't need ->s_lock in ->write_super and are skipped:

 * bfs, nilfs2 - no other uses of s_lock and have internal locks in
	->write_super
 * ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
 * reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
 	->write_super
 * xfs - no other uses of s_lock and uses internal lock (buffer lock on
	superblock buffer) to serialize ->write_super.  Also xfs_fs_write_super
	is superflous and will go away in the next merge window

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:09 -04:00
Al Viro
4aa98cf768 Push BKL down into do_remount_sb()
[folded fix from Jiri Slaby]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:08 -04:00
Al Viro
bbd6851a32 Push lock_super() into the ->remount_fs() of filesystems that care about it
Note that since we can't run into contention between remount_fs and write_super
(due to exclusion on s_umount), we have to care only about filesystems that
touch lock_super() on their own.  Out of those ext3, ext4, hpfs, sysv and ufs
do need it; fat doesn't since its ->remount_fs() only accesses assign-once
data (basically, it's "we have no atime on directories and only have atime on
files for vfat; force nodiratime and possibly noatime into *flags").

[folded a build fix from hch]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:08 -04:00
Christoph Hellwig
6cfd014842 push BKL down into ->put_super
Move BKL into ->put_super from the only caller.  A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment.  Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.

[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:07 -04:00
Al Viro
a9e220f832 No need to do lock_super() for exclusion in generic_shutdown_super()
We can't run into contention on it.  All other callers of lock_super()
either hold s_umount (and we have it exclusive) or hold an active
reference to superblock in question, which prevents the call of
generic_shutdown_super() while the reference is held.  So we can
replace lock_super(s) with get_fs_excl() in generic_shutdown_super()
(and corresponding change for unlock_super(), of course).

Since ext4 expects s_lock held for its put_super, take lock_super()
into it.  The rest of filesystems do not care at all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:07 -04:00
Al Viro
443b94baaa Make sure that all callers of remount hold s_umount exclusive
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:07 -04:00
Christoph Hellwig
e500475338 cleanup sync_supers
Merge the write_super helper into sync_super and move the check for
->write_super earlier so that we can avoid grabbing a reference to
a superblock that doesn't have it.

While we're at it also add a little comment documenting sync_supers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:06 -04:00
Christoph Hellwig
8c85e12512 remove ->write_super call in generic_shutdown_super
We just did a full fs writeout using sync_filesystem before, and if
that's not enough for the filesystem it can perform it's own writeout
in ->put_super, which many filesystems already do.

Move a call to foofs_write_super into every foofs_put_super for now to
guarantee identical behaviour until it's cleaned up by the individual
filesystem maintainers.

Exceptions:

 - affs already has identical copy & pasted code at the beginning of
   affs_put_super so no need to do it twice.
 - xfs does the right thing without it and I have changes pending for
   the xfs tree touching this are so I don't really need conflicts
   here..

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:06 -04:00
Jan Kara
60b0680fa2 vfs: Rename fsync_super() to sync_filesystem() (version 4)
Rename the function so that it better describe what it really does. Also
remove the unnecessary include of buffer_head.h.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:04 -04:00
Jan Kara
c15c54f5f0 vfs: Move syncing code from super.c to sync.c (version 4)
Move sync_filesystems(), __fsync_super(), fsync_super() from
super.c to sync.c where it fits better.

[build fixes folded]

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:04 -04:00
Jan Kara
5cee5815d1 vfs: Make sys_sync() use fsync_super() (version 4)
It is unnecessarily fragile to have two places (fsync_super() and do_sync())
doing data integrity sync of the filesystem. Alter __fsync_super() to
accommodate needs of both callers and use it. So after this patch
__fsync_super() is the only place where we gather all the calls needed to
properly send all data on a filesystem to disk.

Nice bonus is that we get a complete livelock avoidance and write_supers()
is now only used for periodic writeback of superblocks.

sync_blockdevs() introduced a couple of patches ago is gone now.

[build fixes folded]

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:03 -04:00
Jan Kara
429479f031 vfs: Make __fsync_super() a static function (version 4)
__fsync_super() does the same thing as fsync_super(). So change the only
caller to use fsync_super() and make __fsync_super() static. This removes
unnecessarily duplicated call to sync_blockdev() and prepares ground
for the changes to __fsync_super() in the following patches.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:03 -04:00
Jan Kara
bfe881255c vfs: Call ->sync_fs() even if s_dirt is 0 (version 4)
sync_filesystems() has a condition that if wait == 0 and s_dirt == 0, then
->sync_fs() isn't called. This does not really make much sence since s_dirt is
generally used by a filesystem to mean that ->write_super() needs to be called.
But ->sync_fs() does different things. I even suspect that some filesystems
(btrfs?) sets s_dirt just to fool this logic.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:03 -04:00
Jan Kara
5a3e5cb8e0 vfs: Fix sys_sync() and fsync_super() reliability (version 4)
So far, do_sync() called:
  sync_inodes(0);
  sync_supers();
  sync_filesystems(0);
  sync_filesystems(1);
  sync_inodes(1);

This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
and others are hit by this) when racing e.g. with background writeback. A
similar problem hits also other filesystems (e.g. ext2) because of
write_supers() being called before the sync_inodes(1).

Change the ordering of calls in do_sync() - this requires a new function
sync_blockdevs() to preserve the property that block devices are always synced
after write_super() / sync_fs() call.

The same issue is fixed in __fsync_super() function used on umount /
remount read-only.

[AV: build fixes]

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:03 -04:00
Christoph Hellwig
876a9f76ab remove s_async_list
Remove the unused s_async_list in the superblock, a leftover of the
broken async inode deletion code that leaked into mainline.  Having this
in the middle of the sync/unmount path is not helpful for the following
cleanups.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:02 -04:00
npiggin@suse.de
864d7c4c06 fs: move mark_files_ro into file_table.c
This function walks the s_files lock, and operates primarily on the
files in a superblock, so it better belongs here (eg. see also
fs_may_remount_ro).

[AV: ... and it shouldn't be static after that move]

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:02 -04:00
H Hartley Sweeten
ddbaaf3024 NULL noise in fs/super.c:kill_bdev_super()
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Subrata Modak <subrata@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-09 10:49:41 -04:00
Al Viro
74dbbdd7fd New helper: deactivate_locked_super()
Does equivalent of up_write(&s->s_umount); deactivate_super(s);
However, it does not does not unlock it until it's all over.
As the result, it's safe to use to dispose of new superblock on ->get_sb()
failure exits - nobody will see the sucker until it's all over.
Equivalent using up_write/deactivate_super is safe for that purpose
if superblock is either	safe to use or has NULL ->s_root when we unlock.
Normally filesystems take the required precautions, but
	a) we do have bugs in that area in some of them.
	b) up_write/deactivate_super sequence is extremely common,
so the helper makes sense anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-09 10:49:39 -04:00
Serge E. Hallyn
909e6d9479 namespaces: move proc_net_get_sb to a generic fs/super.c helper
The mqueuefs filesystem will use this helper as well.  Proc's main get_sb
could also be made to use it, but that will require a bit more rework.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:09 -07:00
David Howells
800a964787 CacheFiles: Export things for CacheFiles
Export a number of functions for CacheFiles's use.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 16:42:40 +01:00
Linus Torvalds
3ae5080f4c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (37 commits)
  fs: avoid I_NEW inodes
  Merge code for single and multiple-instance mounts
  Remove get_init_pts_sb()
  Move common mknod_ptmx() calls into caller
  Parse mount options just once and copy them to super block
  Unroll essentials of do_remount_sb() into devpts
  vfs: simple_set_mnt() should return void
  fs: move bdev code out of buffer.c
  constify dentry_operations: rest
  constify dentry_operations: configfs
  constify dentry_operations: sysfs
  constify dentry_operations: JFS
  constify dentry_operations: OCFS2
  constify dentry_operations: GFS2
  constify dentry_operations: FAT
  constify dentry_operations: FUSE
  constify dentry_operations: procfs
  constify dentry_operations: ecryptfs
  constify dentry_operations: CIFS
  constify dentry_operations: AFS
  ...
2009-03-27 16:23:12 -07:00
Linus Torvalds
2c9e15a011 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6: (27 commits)
  ext2: Zero our b_size in ext2_quota_read()
  trivial: fix typos/grammar errors in fs/Kconfig
  quota: Coding style fixes
  quota: Remove superfluous inlines
  quota: Remove uppercase aliases for quota functions.
  nfsd: Use lowercase names of quota functions
  jfs: Use lowercase names of quota functions
  udf: Use lowercase names of quota functions
  ufs: Use lowercase names of quota functions
  reiserfs: Use lowercase names of quota functions
  ext4: Use lowercase names of quota functions
  ext3: Use lowercase names of quota functions
  ext2: Use lowercase names of quota functions
  ramfs: Remove quota call
  vfs: Use lowercase names of quota functions
  quota: Remove dqbuf_t and other cleanups
  quota: Remove NODQUOT macro
  quota: Make global quota locks cacheline aligned
  quota: Move quota files into separate directory
  ext4: quota reservation for delayed allocation
  ...
2009-03-27 14:48:34 -07:00
Sukadev Bhattiprolu
a3ec947c85 vfs: simple_set_mnt() should return void
simple_set_mnt() is defined as returning 'int' but always returns 0.
Callers assume simple_set_mnt() never fails and don't properly cleanup if
it were to _ever_ fail.  For instance, get_sb_single() and get_sb_nodev()
should:

        up_write(sb->s_unmount);
        deactivate_super(sb);

if simple_set_mnt() fails.

Since simple_set_mnt() never fails, would be cleaner if it did not
return anything.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27 14:44:03 -04:00
Jens Axboe
a2a9537ac0 Get rid of pdflush_operation() in emergency sync and remount
Opencode a cheasy approach with kevent. The idea here is that we'll
add some generic delayed work infrastructure, which probably wont be
based on pdflush (or maybe it will, in which case we can just add it
back).

This is in preparation for getting rid of pdflush completely.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-03-26 11:01:36 +01:00
Jan Kara
9e3509e273 vfs: Use lowercase names of quota functions
Use lowercase names of quota functions instead of old uppercase ones.

Signed-off-by: Jan Kara <jack@suse.cz>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
2009-03-26 02:18:35 +01:00
Li Zefan
a3cfbb53b1 vfs: add missing unlock in sget()
In sget(), destroy_super(s) is called with s->s_umount held, which makes
lockdep unhappy.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-12 16:20:23 -07:00
Peter Zijlstra
ada723dcd6 fs/super.c: add lockdep annotation to s_umount
Li Zefan said:

Thread 1:
  for ((; ;))
  {
      mount -t cpuset xxx /mnt > /dev/null 2>&1
      cat /mnt/cpus > /dev/null 2>&1
      umount /mnt > /dev/null 2>&1
  }

Thread 2:
  for ((; ;))
  {
      mount -t cpuset xxx /mnt > /dev/null 2>&1
      umount /mnt > /dev/null 2>&1
  }

(Note: It is irrelevant which cgroup subsys is used.)

After a while a lockdep warning showed up:

=============================================
[ INFO: possible recursive locking detected ]
2.6.28 #479
---------------------------------------------
mount/13554 is trying to acquire lock:
 (&type->s_umount_key#19){--..}, at: [<c049d888>] sget+0x5e/0x321

but task is already holding lock:
 (&type->s_umount_key#19){--..}, at: [<c049da0c>] sget+0x1e2/0x321

other info that might help us debug this:
1 lock held by mount/13554:
 #0:  (&type->s_umount_key#19){--..}, at: [<c049da0c>] sget+0x1e2/0x321

stack backtrace:
Pid: 13554, comm: mount Not tainted 2.6.28-mc #479
Call Trace:
 [<c044ad2e>] validate_chain+0x4c6/0xbbd
 [<c044ba9b>] __lock_acquire+0x676/0x700
 [<c044bb82>] lock_acquire+0x5d/0x7a
 [<c049d888>] ? sget+0x5e/0x321
 [<c061b9b8>] down_write+0x34/0x50
 [<c049d888>] ? sget+0x5e/0x321
 [<c049d888>] sget+0x5e/0x321
 [<c045a2e7>] ? cgroup_set_super+0x0/0x3e
 [<c045959f>] ? cgroup_test_super+0x0/0x2f
 [<c045bcea>] cgroup_get_sb+0x98/0x2e7
 [<c045cfb6>] cpuset_get_sb+0x4a/0x5f
 [<c049dfa4>] vfs_kern_mount+0x40/0x7b
 [<c049e02d>] do_kern_mount+0x37/0xbf
 [<c04af4a0>] do_mount+0x5c3/0x61a
 [<c04addd2>] ? copy_mount_options+0x2c/0x111
 [<c04af560>] sys_mount+0x69/0xa0
 [<c0403251>] sysenter_do_call+0x12/0x31

The cause is after alloc_super() and then retry, an old entry in list
fs_supers is found, so grab_super(old) is called, but both functions hold
s_umount lock:

struct super_block *sget(...)
{
	...
retry:
	spin_lock(&sb_lock);
	if (test) {
		list_for_each_entry(old, &type->fs_supers, s_instances) {
			if (!test(old, data))
				continue;
			if (!grab_super(old))  <--- 2nd: down_write(&old->s_umount);
				goto retry;
			if (s)
				destroy_super(s);
			return old;
		}
	}
	if (!s) {
		spin_unlock(&sb_lock);
		s = alloc_super(type);   <--- 1th: down_write(&s->s_umount)
		if (!s)
			return ERR_PTR(-ENOMEM);
		goto retry;
	}
	...
}

It seems like a false positive, and seems like VFS but not cgroup needs to
be fixed.

Peter said:

We can simply put the new s_umount instance in a but lockdep doesn't
particularly cares about subclass order.

If there's any issue with the callers of sget() assuming the s_umount lock
being of sublcass 0, then there is another annotation we can use to fix
that, but lets not bother with that if this is sufficient.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12673

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Menage <menage@google.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-18 15:37:55 -08:00