Commit Graph

30918 Commits (e2cb5f08469c991b187f66fa627d7673c7f3361b)

Author SHA1 Message Date
Linus Torvalds 51f0885e54 vfs,proc: guarantee unique inodes in /proc
Dave Jones found another /proc issue with his Trinity tool: thanks to
the namespace model, we can have multiple /proc dentries that point to
the same inode, aliasing directories in /proc/<pid>/net/ for example.

This ends up being a total disaster, because it acts like hardlinked
directories, and causes locking problems.  We rely on the topological
sort of the inodes pointed to by dentries, and if we have aliased
directories, that odering becomes unreliable.

In short: don't do this.  Multiple dentries with the same (directory)
inode is just a bad idea, and the namespace code should never have
exposed things this way.  But we're kind of stuck with it.

This solves things by just always allocating a new inode during /proc
dentry lookup, instead of using "iget_locked()" to look up existing
inodes by superblock and number.  That actually simplies the code a bit,
at the cost of potentially doing more inode [de]allocations.

That said, the inode lookup wasn't free either (and did a lot of locking
of inodes), so it is probably not that noticeable.  We could easily keep
the old lookup model for non-directory entries, but rather than try to
be excessively clever this just implements the minimal and simplest
workaround for the problem.

Reported-and-tested-by: Dave Jones <davej@redhat.com>
Analyzed-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-22 11:44:04 -07:00
Linus Torvalds 9217cbb8df Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French:
 "Three small CIFS Fixes (the most important of the three fixes a recent
  problem authenticating to Windows 8 using cifs rather than SMB2)"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: ignore everything in SPNEGO blob after mechTypes
  cifs: delay super block destruction until all cifsFileInfo objects are gone
  cifs: map NT_STATUS_SHARING_VIOLATION to EBUSY instead of ETXTBSY
2013-03-21 17:59:22 -07:00
Linus Torvalds d3c926264a Fix a number of regression and other bugs in ext4, most of which were
relatively obscure cornercases or races that were found using
 regression tests.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQIcBAABCAAGBQJRSm5lAAoJENNvdpvBGATwZW8QAN7jMn7IaVCTXXblqgqba4uN
 KvLGRgK7R/n1rIhdHoxJHumwRQLTppVzjDCc8ePnWhdypzMZNuzUvs+OoCFdkDsW
 qf3CmL/p/R1oSiSzzFIs/7wGp7xBZ0l0BWZMFWd9EUg9cqoMBDA6KzcMF95fOtas
 KsjRL+BThacVldS7jyKFwE4BrpXd0Z5V9qZ6wjQPPoBx8sXF4iYA+CZVo5FUKBs8
 6I82LS1/PIYCe3IOSpCgyKXQqRzAYJANv1ndken5wW8jWT2R58e360OwZEVcpIN9
 /caov+F5OKfk4iOGq3b+vwRplNhAI2S6C4vhMbmS2GPWE8Fnr8gubyqNAIIs5R/y
 3zYHdqZESfuEF7K3QoAepiJhi3YIoRxXC1FxD7uxx7VBRhW2w8Ij5hlXhuSoh24M
 MUiXgCeIxQb+ZfUx0OHV++LSOHVccU4y7Z0X+LpXQa6tEMBuSgK6yCKsGkyr8APN
 gPMupTptgyUE3tFaCjqc7QKtmoeRAMSvzfqEyV6DlblIOe+3f/RJzRO222Xc4kxq
 D9t2tOuPoXsR+ivtS5pEcrZkE4Y2hkJbJzb7XXvfoETixYsuX6VkiPK/D68S9eRe
 VelqTM2lHPJi/3Wkle0p4pzWpEq70D8qZVp4TKLHMJCTQKpwUfopm5lvln87lc7w
 4JDORIx/ed1u8MMTJlmG
 =X3vc
 -----END PGP SIGNATURE-----

Merge tag 'ext4_for_linue' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 fixes from Ted Ts'o:
 "Fix a number of regression and other bugs in ext4, most of which were
  relatively obscure cornercases or races that were found using
  regression tests."

* tag 'ext4_for_linue' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (21 commits)
  ext4: fix data=journal fast mount/umount hang
  ext4: fix ext4_evict_inode() racing against workqueue processing code
  ext4: fix memory leakage in mext_check_coverage
  ext4: use s_extent_max_zeroout_kb value as number of kb
  ext4: use atomic64_t for the per-flexbg free_clusters count
  jbd2: fix use after free in jbd2_journal_dirty_metadata()
  ext4: reserve metadata block for every delayed write
  ext4: update reserved space after the 'correction'
  ext4: do not use yield()
  ext4: remove unused variable in ext4_free_blocks()
  ext4: fix WARN_ON from ext4_releasepage()
  ext4: fix the wrong number of the allocated blocks in ext4_split_extent()
  ext4: update extent status tree after an extent is zeroed out
  ext4: fix wrong m_len value after unwritten extent conversion
  ext4: add self-testing infrastructure to do a sanity check
  ext4: avoid a potential overflow in ext4_es_can_be_merged()
  ext4: invalidate extent status tree during extent migration
  ext4: remove unnecessary wait for extent conversion in ext4_fallocate()
  ext4: add warning to ext4_convert_unwritten_extents_endio
  ext4: disable merging of uninitialized extents
  ...
2013-03-21 17:56:10 -07:00
Jeff Layton f853c61688 cifs: ignore everything in SPNEGO blob after mechTypes
We've had several reports of people attempting to mount Windows 8 shares
and getting failures with a return code of -EINVAL. The default sec=
mode changed recently to sec=ntlmssp. With that, we expect and parse a
SPNEGO blob from the server in the NEGOTIATE reply.

The current decode_negTokenInit function first parses all of the
mechTypes and then tries to parse the rest of the negTokenInit reply.
The parser however currently expects a mechListMIC or nothing to follow the
mechTypes, but Windows 8 puts a mechToken field there instead to carry
some info for the new NegoEx stuff.

In practice, we don't do anything with the fields after the mechTypes
anyway so I don't see any real benefit in continuing to parse them.
This patch just has the kernel ignore the fields after the mechTypes.
We'll probably need to reinstate some of this if we ever want to support
NegoEx.

Reported-by: Jason Burgess <jason@jacknife2.dns2go.com>
Reported-by: Yan Li <elliot.li.tech@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2013-03-21 12:40:19 -05:00
Theodore Ts'o 2b405bfa84 ext4: fix data=journal fast mount/umount hang
In data=journal mode, if we unmount the file system before a
transaction has a chance to complete, when the journal inode is being
evicted, we can end up calling into jbd2_log_wait_commit() for the
last transaction, after the journalling machinery has been shut down.

Arguably we should adjust ext4_should_journal_data() to return FALSE
for the journal inode, but the only place it matters is
ext4_evict_inode(), and so to save a bit of CPU time, and to make the
patch much more obviously correct by inspection(tm), we'll fix it by
explicitly not trying to waiting for a journal commit when we are
evicting the journal inode, since it's guaranteed to never succeed in
this case.

This can be easily replicated via: 

     mount -t ext4 -o data=journal /dev/vdb /vdb ; umount /vdb

------------[ cut here ]------------
WARNING: at /usr/projects/linux/ext4/fs/jbd2/journal.c:542 __jbd2_log_start_commit+0xba/0xcd()
Hardware name: Bochs
JBD2: bad log_start_commit: 3005630206 3005630206 0 0
Modules linked in:
Pid: 2909, comm: umount Not tainted 3.8.0-rc3 #1020
Call Trace:
 [<c015c0ef>] warn_slowpath_common+0x68/0x7d
 [<c02b7e7d>] ? __jbd2_log_start_commit+0xba/0xcd
 [<c015c177>] warn_slowpath_fmt+0x2b/0x2f
 [<c02b7e7d>] __jbd2_log_start_commit+0xba/0xcd
 [<c02b8075>] jbd2_log_start_commit+0x24/0x34
 [<c0279ed5>] ext4_evict_inode+0x71/0x2e3
 [<c021f0ec>] evict+0x94/0x135
 [<c021f9aa>] iput+0x10a/0x110
 [<c02b7836>] jbd2_journal_destroy+0x190/0x1ce
 [<c0175284>] ? bit_waitqueue+0x50/0x50
 [<c028d23f>] ext4_put_super+0x52/0x294
 [<c020efe3>] generic_shutdown_super+0x48/0xb4
 [<c020f071>] kill_block_super+0x22/0x60
 [<c020f3e0>] deactivate_locked_super+0x22/0x49
 [<c020f5d6>] deactivate_super+0x30/0x33
 [<c0222795>] mntput_no_expire+0x107/0x10c
 [<c02233a7>] sys_umount+0x2cf/0x2e0
 [<c02233ca>] sys_oldumount+0x12/0x14
 [<c08096b8>] syscall_call+0x7/0xb
---[ end trace 6a954cc790501c1f ]---
jbd2_log_wait_commit: error: j_commit_request=-1289337090, tid=0

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
2013-03-20 09:42:11 -04:00
Theodore Ts'o 1ada47d946 ext4: fix ext4_evict_inode() racing against workqueue processing code
Commit 84c17543ab (ext4: move work from io_end to inode) triggered a
regression when running xfstest #270 when the file system is mounted
with dioread_nolock.

The problem is that after ext4_evict_inode() calls ext4_ioend_wait(),
this guarantees that last io_end structure has been freed, but it does
not guarantee that the workqueue structure, which was moved into the
inode by commit 84c17543ab, is actually finished.  Once
ext4_flush_completed_IO() calls ext4_free_io_end() on CPU #1, this
will allow ext4_ioend_wait() to return on CPU #2, at which point the
evict_inode() codepath can race against the workqueue code on CPU #1
accessing EXT4_I(inode)->i_unwritten_work to find the next item of
work to do.

Fix this by calling cancel_work_sync() in ext4_ioend_wait(), which
will be renamed ext4_ioend_shutdown(), since it is only used by
ext4_evict_inode().  Also, move the call to ext4_ioend_shutdown()
until after truncate_inode_pages() and filemap_write_and_wait() are
called, to make sure all dirty pages have been written back and
flushed from the page cache first.

BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e
*pdpt = 0000000030bc3001 *pde = 0000000000000000 
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in:
Pid: 6, comm: kworker/u:0 Not tainted 3.8.0-rc3-00013-g84c1754-dirty #91 Bochs Bochs
EIP: 0060:[<c01dda6a>] EFLAGS: 00010046 CPU: 0
EIP is at cwq_activate_delayed_work+0x3b/0x7e
EAX: 00000000 EBX: 00000000 ECX: f505fe54 EDX: 00000000
ESI: ed5b697c EDI: 00000006 EBP: f64b7e8c ESP: f64b7e84
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 8005003b CR2: 00000000 CR3: 30bc2000 CR4: 000006f0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process kworker/u:0 (pid: 6, ti=f64b6000 task=f64b4160 task.ti=f64b6000)
Stack:
 f505fe00 00000006 f64b7e9c c01de3d7 f6435540 00000003 f64b7efc c01def1d
 f6435540 00000002 00000000 0000008a c16d0808 c040a10b c16d07d8 c16d08b0
 f505fe00 c16d0780 00000000 00000000 ee153df4 c1ce4a30 c17d0e30 00000000
Call Trace:
 [<c01de3d7>] cwq_dec_nr_in_flight+0x71/0xfb
 [<c01def1d>] process_one_work+0x5d8/0x637
 [<c040a10b>] ? ext4_end_bio+0x300/0x300
 [<c01e3105>] worker_thread+0x249/0x3ef
 [<c01ea317>] kthread+0xd8/0xeb
 [<c01e2ebc>] ? manage_workers+0x4bb/0x4bb
 [<c023a370>] ? trace_hardirqs_on+0x27/0x37
 [<c0f1b4b7>] ret_from_kernel_thread+0x1b/0x28
 [<c01ea23f>] ? __init_kthread_worker+0x71/0x71
Code: 01 83 15 ac ff 6c c1 00 31 db 89 c6 8b 00 a8 04 74 12 89 c3 30 db 83 05 b0 ff 6c c1 01 83 15 b4 ff 6c c1 00 89 f0 e8 42 ff ff ff <8b> 13 89 f0 83 05 b8 ff 6c c1
 6c c1 00 31 c9 83
EIP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e SS:ESP 0068:f64b7e84
CR2: 0000000000000000
---[ end trace a1923229da53d8a4 ]---

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
2013-03-20 09:39:42 -04:00
Linus Torvalds 10b38669d6 - Fix for a potential infinite loop which was introduced in 4d559a3bcb
- Fix for the return type of xfs_iomap_eof_prealloc_initial_size
   from a1e16c2666
 - Fix for a failed buffer readahead causing subsequent callers to
   fail incorrectly
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.11 (GNU/Linux)
 
 iQIcBAABAgAGBQJRSOIAAAoJENaLyazVq6ZODqQP/2m1iZVIA9CXFf5hS2QZgkc2
 MHq+QaQ1aaZlAIRCnZO4XrWoLw4tH7AmsHA7dVJVz/ZhVrJg4ahfdSS6qR5EGWFb
 I5uE8LD8ZhpIiW6mBytJ7g9ST6xnaeean2sMwa0BcVK3uF84nO/uBopntZVrVlZE
 sMuklZe8GfxDpF6SBxVGG+5+OeLXzFmf+s+xoCYN410uuzYoT8/jveFP6a5ARcmH
 xEcOJA2+3o2z4/fsdx/Euf6LnDMSyOsAFUJCtnmBdKUA5w9DrJJqGpDDPEkg9h6d
 /DTPYXEWx6+w4xoMnIf09oEdCSamBVTWcRFXtftN03VNrbRNtyVwAc8HUaSNmt0p
 I3P/b5NJ5guH7uK72jp61N2RP7D5KOqwkwR58Y1SJWuwcgatYuB3NM5UeUyJBILj
 ViZ4DsKGE6BCl8T3hwkN+mxSxB+o7O8AypjWdEviBXbVIG9CwOxr1IEatl3eyV5T
 8QsNFb0LJcWzl1+F/uUYe1Goeqxvzupt7omUaRONdMnac3uFIk0ARrdxXFgawIJ9
 lgeftBCmMkqqLZUACSfmfCYNwyupz3E6bYB7Azwx01qg7CzTPUfIL2SxqDYp2dup
 /s+R7HL4HOJ0FCzjCZxHHO/1jsWgu265dJdpaQw/UcIe2IuEFGr558deHEM62bDW
 rWCVHj5eY5NRGyzSwzqB
 =41Vk
 -----END PGP SIGNATURE-----

Merge tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs

Pull XFS fixes from Ben Myers:

 - Fix for a potential infinite loop which was introduced in commit
   4d559a3bcb ("xfs: limit speculative prealloc near ENOSPC
   thresholds")

 - Fix for the return type of xfs_iomap_eof_prealloc_initial_size from
   commit a1e16c2666 ("xfs: limit speculative prealloc size on sparse
   files")

 - Fix for a failed buffer readahead causing subsequent callers to fail
   incorrectly

* tag 'for-linus-v3.9-rc4' of git://oss.sgi.com/xfs/xfs:
  xfs: ensure we capture IO errors correctly
  xfs: fix xfs_iomap_eof_prealloc_initial_size type
  xfs: fix potential infinite loop in xfs_iomap_prealloc_size()
2013-03-19 15:17:40 -07:00
Dave Chinner e001873853 xfs: ensure we capture IO errors correctly
Failed buffer readahead can leave the buffer in the cache marked
with an error. Most callers that then issue a subsequent read on the
buffer do not zero the b_error field out, and so we may incorectly
detect an error during IO completion due to the stale error value
left on the buffer.

Avoid this problem by zeroing the error before IO submission. This
ensures that the only IO errors that are detected those captured
from are those captured from bio submission or completion.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit c163f9a176)
2013-03-18 13:39:10 -05:00
Mark Tinguely 3325beed46 xfs: fix xfs_iomap_eof_prealloc_initial_size type
Fix the return type of xfs_iomap_eof_prealloc_initial_size() to
xfs_fsblock_t to reflect the fact that the return value may be an
unsigned 64 bits if XFS_BIG_BLKNOS is defined.

Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit e8108cedb1)
2013-03-18 13:38:50 -05:00
Brian Foster 83cdadd8b0 xfs: fix potential infinite loop in xfs_iomap_prealloc_size()
If freesp == 0, we could end up in an infinite loop while squashing
the preallocation. Break the loop when we've killed the prealloc
entirely.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

(cherry picked from commit e78c420bfc)
2013-03-18 13:30:38 -05:00
Dmitry Monakhov 0e401101db ext4: fix memory leakage in mext_check_coverage
Regression was introduced by following commit 8c854473
TESTCASE (git://oss.sgi.com/xfs/cmds/xfstests.git):
#while true;do ./check 301 || break ;done

Also fix potential memory leakage in get_ext_path() once
ext4_ext_find_extent() have failed.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-18 11:40:19 -04:00
Linus Torvalds 08637024ab Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "Eric's rcu barrier patch fixes a long standing problem with our
  unmount code hanging on to devices in workqueue helpers.  Liu Bo
  nailed down a difficult assertion for in-memory extent mappings."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: fix warning of free_extent_map
  Btrfs: fix warning when creating snapshots
  Btrfs: return as soon as possible when edquot happens
  Btrfs: return EIO if we have extent tree corruption
  btrfs: use rcu_barrier() to wait for bdev puts at unmount
  Btrfs: remove btrfs_try_spin_lock
  Btrfs: get better concurrency for snapshot-aware defrag work
2013-03-17 11:04:14 -07:00
Liu Bo 3b2775942d Btrfs: fix warning of free_extent_map
Users report that an extent map's list is still linked when it's actually
going to be freed from cache.

The story is that

a) when we're going to drop an extent map and may split this large one into
smaller ems, and if this large one is flagged as EXTENT_FLAG_LOGGING which means
that it's on the list to be logged, then the smaller ems split from it will also
be flagged as EXTENT_FLAG_LOGGING, and this is _not_ expected.

b) we'll keep ems from unlinking the list and freeing when they are flagged with
EXTENT_FLAG_LOGGING, because the log code holds one reference.

The end result is the warning, but the truth is that we set the flag
EXTENT_FLAG_LOGGING only during fsync.

So clear flag EXTENT_FLAG_LOGGING for extent maps split from a large one.

Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de>
Reported-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-15 21:51:49 -04:00
Linus Torvalds 40e4591d94 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull ext2, ext3, reiserfs, quota fixes from Jan Kara:
 "A fix for regression in ext2, and a format string issue in ext3.  The
  rest isn't too serious."

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  ext2: Fix BUG_ON in evict() on inode deletion
  reiserfs: Use kstrdup instead of kmalloc/strcpy
  ext3: Fix format string issues
  quota: add missing use of dq_data_lock in __dquot_initialize
2013-03-14 12:11:28 -07:00
Liu Bo 7c2ec3f073 Btrfs: fix warning when creating snapshots
Creating snapshot passes extent_root to commit its transaction,
but it can lead to the warning of checking root for quota in
the __btrfs_end_transaction() when someone else is committing
the current transaction.  Since we've recorded the needed root
in trans_handle, just use it to get rid of the warning.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:57:30 -04:00
Wang Shilong 720f1e2060 Btrfs: return as soon as possible when edquot happens
If one of qgroup fails to reserve firstly, we should return immediately,
it is unnecessary to continue check.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:57:29 -04:00
Josef Bacik 492104c866 Btrfs: return EIO if we have extent tree corruption
The callers of lookup_inline_extent_info all handle getting an error back
properly, so return an error if we have corruption instead of being a jerk and
panicing.  Still WARN_ON() since this is kind of crucial and I've been seeing it
a bit too much recently for my taste, I think we're doing something wrong
somewhere.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:57:29 -04:00
Eric Sandeen bc178622d4 btrfs: use rcu_barrier() to wait for bdev puts at unmount
Doing this would reliably fail with -EBUSY for me:

# mount /dev/sdb2 /mnt/scratch; umount /mnt/scratch; mkfs.btrfs -f /dev/sdb2
...
unable to open /dev/sdb2: Device or resource busy

because mkfs.btrfs tries to open the device O_EXCL, and somebody still has it.

Using systemtap to track bdev gets & puts shows a kworker thread doing a
blkdev put after mkfs attempts a get; this is left over from the unmount
path:

btrfs_close_devices
	__btrfs_close_devices
		call_rcu(&device->rcu, free_device);
			free_device
				INIT_WORK(&device->rcu_work, __free_device);
				schedule_work(&device->rcu_work);

so unmount might complete before __free_device fires & does its blkdev_put.

Adding an rcu_barrier() to btrfs_close_devices() causes unmount to wait
until all blkdev_put()s are done, and the device is truly free once
unmount completes.

Cc: stable@vger.kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:57:29 -04:00
Liu Bo d340d2475c Btrfs: remove btrfs_try_spin_lock
Remove a useless function declaration

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:57:10 -04:00
Liu Bo a09a0a705d Btrfs: get better concurrency for snapshot-aware defrag work
Using spinning case instead of blocking will result in better concurrency
overall.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-14 14:50:19 -04:00
Linus Torvalds aea8b5d1e5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace bugfixes from Eric Biederman:
 "This tree includes a partial revert for "fs: Limit sys_mount to only
  request filesystem modules." When I added the new style module aliases
  to the filesystems I deleted the old ones.  A bad move.  It turns out
  that distributions like Arch linux use module aliases when
  constructing ramdisks.  Which meant ultimately that an ext3 filesystem
  mounted with ext4 would not result in the ext4 module being put into
  the ramdisk.

  The other change in this tree adds a handful of filesystem module
  alias I simply failed to add the first time.  Which inconvinienced a
  few folks using cifs.

  I don't want to inconvinience folks any longer than I have to so here
  are these trivial fixes."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  fs: Readd the fs module aliases.
  fs: Limit sys_mount to only request filesystem modules. (Part 3)
2013-03-13 15:47:50 -07:00
Tejun Heo ebd6c70714 nfsd: convert to idr_alloc()
idr_get_new*() and friends are about to be deprecated.  Convert to the
new idr_alloc() interface.

Only compile-tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Tested-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:45 -07:00
Tejun Heo 801cb2d62d nfsd: remove unused get_new_stid()
get_new_stid() is no longer used since commit 3abdb60712 ("nfsd4:
simplify idr allocation").  Remove it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:45 -07:00
Mateusz Guzik 24261fc23d cifs: delay super block destruction until all cifsFileInfo objects are gone
cifsFileInfo objects hold references to dentries and it is possible that
these will still be around in workqueues when VFS decides to kill super
block during unmount.

This results in panics like this one:
BUG: Dentry ffff88001f5e76c0{i=66b4a,n=1M-2} still in use (1) [unmount of cifs cifs]
------------[ cut here ]------------
kernel BUG at fs/dcache.c:943!
[..]
Process umount (pid: 1781, threadinfo ffff88003d6e8000, task ffff880035eeaec0)
[..]
Call Trace:
 [<ffffffff811b44f3>] shrink_dcache_for_umount+0x33/0x60
 [<ffffffff8119f7fc>] generic_shutdown_super+0x2c/0xe0
 [<ffffffff8119f946>] kill_anon_super+0x16/0x30
 [<ffffffffa036623a>] cifs_kill_sb+0x1a/0x30 [cifs]
 [<ffffffff8119fcc7>] deactivate_locked_super+0x57/0x80
 [<ffffffff811a085e>] deactivate_super+0x4e/0x70
 [<ffffffff811bb417>] mntput_no_expire+0xd7/0x130
 [<ffffffff811bc30c>] sys_umount+0x9c/0x3c0
 [<ffffffff81657c19>] system_call_fastpath+0x16/0x1b

Fix this by making each cifsFileInfo object hold a reference to cifs
super block, which implicitly keeps VFS super block around as well.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Cc: <stable@vger.kernel.org>
Reported-and-Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2013-03-13 14:12:06 -05:00
Sachin Prabhu 47c78f4a70 cifs: map NT_STATUS_SHARING_VIOLATION to EBUSY instead of ETXTBSY
NT_SHARING_VIOLATION errors are mapped to ETXTBSY which is unexpected
for operations such as unlink where we can hit these errors.

The patch maps the error NT_SHARING_VIOLATION to EBUSY instead. The
patch also replaces all instances of ETXTBSY in
cifs_rename_pending_delete() with EBUSY.

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2013-03-13 14:09:20 -05:00
Jan Kara c288d29696 ext2: Fix BUG_ON in evict() on inode deletion
Commit 8e3dffc6 introduced a regression where deleting inode with
large extended attributes leads to triggering
  BUG_ON(inode->i_state != (I_FREEING | I_CLEAR))
in fs/inode.c:evict(). That happens because freeing of xattr block
dirtied the inode and it happened after clear_inode() has been called.

Fix the issue by moving removal of xattr block into ext2_evict_inode()
before clear_inode() call close to a place where data blocks are
truncated. That is also more logical place and removes surprising
requirement that ext2_free_blocks() mustn't dirty the inode.

Reported-by: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-03-13 15:23:44 +01:00
Eric W. Biederman fa7614ddd6 fs: Readd the fs module aliases.
I had assumed that the only use of module aliases for filesystems
prior to "fs: Limit sys_mount to only request filesystem modules."
was in request_module.  It turns out I was wrong.  At least mkinitcpio
in Arch linux uses these aliases.

So readd the preexising aliases, to keep from breaking userspace.

Userspace eventually will have to follow and use the same aliases the
kernel does.  So at some point we may be delete these aliases without
problems.  However that day is not today.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-12 18:55:21 -07:00
Mathieu Desnoyers 8aec0f5d41 Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().

This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:

Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().

I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.

While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.

And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-12 11:05:45 -07:00
Lukas Czerner 4f42f80a8f ext4: use s_extent_max_zeroout_kb value as number of kb
Currently when converting extent to initialized, we have to decide
whether to zeroout part/all of the uninitialized extent in order to
avoid extent tree growing rapidly.

The decision is made by comparing the size of the extent with the
configurable value s_extent_max_zeroout_kb which is in kibibytes units.

However when converting it to number of blocks we currently use it as it
was in bytes. This is obviously bug and it will result in ext4 _never_
zeroout extents, but rather always split and convert parts to
initialized while leaving the rest uninitialized in default setting.

Fix this by using s_extent_max_zeroout_kb as kibibytes.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2013-03-12 12:40:04 -04:00
Al Viro a930d87905 vfs: fix pipe counter breakage
If you open a pipe for neither read nor write, the pipe code will not
add any usage counters to the pipe, causing the 'struct pipe_inode_info"
to be potentially released early.

That doesn't normally matter, since you cannot actually use the pipe,
but the pipe release code - particularly fasync handling - still expects
the actual pipe infrastructure to all be there.  And rather than adding
NULL pointer checks, let's just disallow this case, the same way we
already do for the named pipe ("fifo") case.

This is ancient going back to pre-2.4 days, and until trinity, nobody
naver noticed.

Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-12 08:29:17 -07:00
Theodore Ts'o 90ba983f68 ext4: use atomic64_t for the per-flexbg free_clusters count
A user who was using a 8TB+ file system and with a very large flexbg
size (> 65536) could cause the atomic_t used in the struct flex_groups
to overflow.  This was detected by PaX security patchset:

http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551

This bug was introduced in commit 9f24e4208f, so it's been around
since 2.6.30.  :-(

Fix this by using an atomic64_t for struct orlav_stats's
free_clusters.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Cc: stable@vger.kernel.org
2013-03-11 23:39:59 -04:00
Ionut-Gabriel Radu af591ad896 reiserfs: Use kstrdup instead of kmalloc/strcpy
Signed-off-by: Ionut-Gabriel Radu <ihonius@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-03-11 22:05:57 +01:00
Lars-Peter Clausen 8d0c2d10dd ext3: Fix format string issues
ext3_msg() takes the printk prefix as the second parameter and the
format string as the third parameter. Two callers of ext3_msg omit the
prefix and pass the format string as the second parameter and the first
parameter to the format string as the third parameter. In both cases
this string comes from an arbitrary source. Which means the string may
contain format string characters, which will
lead to undefined and potentially harmful behavior.

The issue was introduced in commit 4cf46b67eb("ext3: Unify log messages
in ext3") and is fixed by this patch.

CC: stable@vger.kernel.org
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-03-11 22:05:56 +01:00
Jeff Mahoney 68ac8bfb6a quota: add missing use of dq_data_lock in __dquot_initialize
The bulk of __dquot_initialize runs under the dqptr_sem which
protects the inode->i_dquot pointers. It doesn't protect the
dereferenced contents, though. Those are protected by the
dq_data_lock, which is missing around the dquot_resv_space call.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-03-11 22:05:56 +01:00
Jan Kara ad56edad08 jbd2: fix use after free in jbd2_journal_dirty_metadata()
jbd2_journal_dirty_metadata() didn't get a reference to journal_head it
was working with. This is OK in most of the cases since the journal head
should be attached to a transaction but in rare occasions when we are
journalling data, __ext4_journalled_writepage() can race with
jbd2_journal_invalidatepage() stripping buffers from a page and thus
journal head can be freed under hands of jbd2_journal_dirty_metadata().

Fix the problem by getting own journal head reference in
jbd2_journal_dirty_metadata() (and also in jbd2_journal_set_triggers()
which can possibly have the same issue).

Reported-by: Zheng Liu <gnehzuil.liu@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2013-03-11 13:24:56 -04:00
Eric W. Biederman 3e64fe5b21 fs: Limit sys_mount to only request filesystem modules. (Part 3)
Somehow I failed to add the MODULE_ALIAS_FS for cifs, hostfs, hpfs,
squashfs, and udf despite what I thought were my careful checks :(

Add them now.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-11 07:09:48 -07:00
Marco Stornelli bc077320f8 hostfs: fix a not needed double check
With the commit 3be2be0a32 we removed vmtruncate,
but actaully there is no need to call inode_newsize_ok() because the checks are
already done in inode_change_ok() at the begin of the function.

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2013-03-11 10:08:02 +01:00
Lukas Czerner 386ad67c9a ext4: reserve metadata block for every delayed write
Currently we only reserve space (data+metadata) in delayed allocation if
we're allocating from new cluster (which is always in non-bigalloc file
system) which is ok for data blocks, because we reserve the whole cluster.

However we have to reserve metadata for every delayed block we're going
to write because every block could potentially require metedata block
when we need to grow the extent tree.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
2013-03-10 22:50:00 -04:00
Lukas Czerner 232ec8720d ext4: update reserved space after the 'correction'
Currently in ext4_ext_map_blocks() in delayed allocation writeback
we would update the reservation and after that check whether we claimed
cluster outside of the range of the allocation and if so, we'll give the
block back to the reservation pool.

However this also means that if the number of reserved data block
dropped to zero before the correction, we would release all the metadata
reservation as well, however we might still need it because the we're
not done with the delayed allocation and there might be more blocks to
come. This will result in error messages such as:

EXT4-fs warning (device sdb): ext4_da_update_reserve_space:361: ino 12,
allocated 1 with only 0 reserved metadata blocks (releasing 1 blocks
with reserved 1 data blocks)

This will only happen on bigalloc file system and it can be easily
reproduced using fiemap-tester from xfstests like this:

./src/fiemap-tester -m DHDHDHDHD -S -p0 /mnt/test/file

Or using xfstests such as 225.

Fix this by doing the correction first and updating the reservation
after that so that we do not accidentally decrease
i_reserved_data_blocks to zero.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-10 22:46:30 -04:00
Lukas Czerner bb8b20ed94 ext4: do not use yield()
Using yield() is strongly discouraged (see sched/core.c) especially
since we can just use cond_resched().

Replace all use of yield() with cond_resched().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-10 22:28:09 -04:00
Lukas Czerner e3d85c3660 ext4: remove unused variable in ext4_free_blocks()
Remove unused variable 'freed' in ext4_free_blocks().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-10 22:21:49 -04:00
Jan Kara e1c36595be ext4: fix WARN_ON from ext4_releasepage()
ext4_releasepage() warns when it is passed a page with PageChecked set.
However this can correctly happen when invalidate_inode_pages2_range()
invalidates pages - and we should fail the release in that case. Since
the page was dirty anyway, it won't be discarded and no harm has
happened but it's good to be safe. Also remove bogus page_has_buffers()
check - we are guaranteed page has buffers in this function.

Reported-by: Zheng Liu <gnehzuil.liu@gmail.com>
Tested-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
2013-03-10 22:19:00 -04:00
Zheng Liu 3a2256702e ext4: fix the wrong number of the allocated blocks in ext4_split_extent()
This commit fixes a wrong return value of the number of the allocated
blocks in ext4_split_extent.  When the length of blocks we want to
allocate is greater than the length of the current extent, we return a
wrong number.  Let's see what happens in the following case when we
call ext4_split_extent().

  map: [48, 72]
  ex:  [32, 64, u]

'ex' will be split into two parts:
  ex1: [32, 47, u]
  ex2: [48, 64, w]

'map->m_len' is returned from this function, and the value is 24.  But
the real length is 16.  So it should be fixed.

Meanwhile in this commit we use right length of the allocated blocks
when get_reserved_cluster_alloc in ext4_ext_handle_uninitialized_extents
is called.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: stable@vger.kernel.org
2013-03-10 21:20:23 -04:00
Zheng Liu adb2355104 ext4: update extent status tree after an extent is zeroed out
When we try to split an extent, this extent could be zeroed out and mark
as initialized.  But we don't know this in ext4_map_blocks because it
only returns a length of allocated extent.  Meanwhile we will mark this
extent as uninitialized because we only check m_flags.

This commit update extent status tree when we try to split an unwritten
extent.  We don't need to worry about the status of this extent because
we always mark it as initialized.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
2013-03-10 21:13:05 -04:00
Zheng Liu cdee78433c ext4: fix wrong m_len value after unwritten extent conversion
The ext4_ext_handle_uninitialized_extents() function was assuming the
return value of ext4_ext_map_blocks() is equal to map->m_len.  This
incorrect assumption was harmless until we started use status tree as
a extent cache because we need to update status tree according to
'm_len' value.

Meanwhile this commit marks EXT4_MAP_MAPPED flag after unwritten extent
conversion.  It shouldn't cause a bug because we update status tree
according to checking EXT4_MAP_UNWRITTEN flag.  But it should be fixed.

After applied this commit, the following error message from self-testing
infrastructure disappears.

    ...
    kernel: ES len assertation failed for inode: 230 retval 1 !=
    map->m_len 3 in ext4_map_blocks (allocation)
    ...

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
2013-03-10 21:08:52 -04:00
Dmitry Monakhov 921f266bc6 ext4: add self-testing infrastructure to do a sanity check
This commit adds a self-testing infrastructure like extent tree does to
do a sanity check for extent status tree.  After status tree is as a
extent cache, we'd better to make sure that it caches right result.

After applied this commit, we will get a lot of messages when we run
xfstests as below.

...
kernel: ES len assertation failed for inode: 230 retval 1 != map->m_len
3 in ext4_map_blocks (allocation)
...
kernel: ES cache assertation failed for inode: 230 es_cached ex
[974/2/4781/20] != found ex [974/1/4781/1000]
...
kernel: ES insert assertation failed for inode: 635 ex_status
[0/45/21388/w] != es_status [44/1/21432/u]
...

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-10 21:01:03 -04:00
Zheng Liu bd384364c1 ext4: avoid a potential overflow in ext4_es_can_be_merged()
Check the length of an extent to avoid a potential overflow in
ext4_es_can_be_merged().

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>
2013-03-10 20:48:59 -04:00
Linus Torvalds 72932611b4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace bugfixes from Eric Biederman:
 "This is three simple fixes against 3.9-rc1.  I have tested each of
  these fixes and verified they work correctly.

  The userns oops in key_change_session_keyring and the BUG_ON triggered
  by proc_ns_follow_link were found by Dave Jones.

  I am including the enhancement for mount to only trigger requests of
  filesystem modules here instead of delaying this for the 3.10 merge
  window because it is both trivial and the kind of change that tends to
  bit-rot if left untouched for two months."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: Use nd_jump_link in proc_ns_follow_link
  fs: Limit sys_mount to only request filesystem modules (Part 2).
  fs: Limit sys_mount to only request filesystem modules.
  userns: Stop oopsing in key_change_session_keyring
2013-03-09 16:51:13 -08:00
Eric W. Biederman db04dc679b proc: Use nd_jump_link in proc_ns_follow_link
Update proc_ns_follow_link to use nd_jump_link instead of just
manually updating nd.path.dentry.

This fixes the BUG_ON(nd->inode != parent->d_inode) reported by Dave
Jones and reproduced trivially with mkdir /proc/self/ns/uts/a.

Sigh it looks like the VFS change to require use of nd_jump_link
happend while proc_ns_follow_link was baking and since the common case
of proc_ns_follow_link continued to work without problems the need for
making this change was overlooked.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-09 00:14:45 -08:00
Linus Torvalds 0aefda3e81 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs fixes from Chris Mason:
 "These are scattered fixes and one performance improvement.  The
  biggest functional change is in how we throttle metadata changes.  The
  new code bumps our average file creation rate up by ~13% in fs_mark,
  and lowers CPU usage.

  Stefan bisected out a regression in our allocation code that made
  balance loop on extents larger than 256MB."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: improve the delayed inode throttling
  Btrfs: fix a mismerge in btrfs_balance()
  Btrfs: enforce min_bytes parameter during extent allocation
  Btrfs: allow running defrag in parallel to administrative tasks
  Btrfs: avoid deadlock on transaction waiting list
  Btrfs: do not BUG_ON on aborted situation
  Btrfs: do not BUG_ON in prepare_to_reloc
  Btrfs: free all recorded tree blocks on error
  Btrfs: build up error handling for merge_reloc_roots
  Btrfs: check for NULL pointer in updating reloc roots
  Btrfs: fix unclosed transaction handler when the async transaction commitment fails
  Btrfs: fix wrong handle at error path of create_snapshot() when the commit fails
  Btrfs: use set_nlink if our i_nlink is 0
2013-03-08 17:33:20 -08:00