linux-toradex.git/fs/ext4/inode.c, branch v3.6.5

ext4: fix mtime update in nodelalloc mode

2012-10-12T20:50:25+00:00

commit 041bbb6d369811e948ae01f3d00414264076be35 upstream.

Commits 5e8830dc85d0 and 41c4d25f78c0 introduced a regression into
v3.6-rc1 for ext4 in nodealloc mode, such that mtime updates would not
take place for files modified via mmap if the page was already in the
page cache.  This would also affect ext3 file systems mounted using
the ext4 file system driver.

The problem was that ext4_page_mkwrite() had a shortcut which would
avoid calling __block_page_mkwrite() under some circumstances, and the
above two commit transferred the responsibility of calling
file_update_time() to __block_page_mkwrite --- which woudln't get
called in some circumstances.

Since __block_page_mkwrite() only has three callers,
block_page_mkwrite(), ext4_page_mkwrite, and nilfs_page_mkwrite(), the
best way to solve this is to move the responsibility for calling
file_update_time() to its caller.

This problem was found via xfstests #215 with a file system mounted
with -o nodelalloc.

Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Jan Kara 
Cc: KONISHI Ryusuke 
Signed-off-by: Greg Kroah-Hartman

ext4: fix fdatasync() for files with only i_size changes

2012-10-12T20:50:24+00:00

commit b71fc079b5d8f42b2a52743c8d2f1d35d655b1c5 upstream.

Code tracking when transaction needs to be committed on fdatasync(2) forgets
to handle a situation when only inode's i_size is changed. Thus in such
situations fdatasync(2) doesn't force transaction with new i_size to disk
and that can result in wrong i_size after a crash.

Fix the issue by updating inode's i_datasync_tid whenever its size is
updated.

Reported-by: Kristian Nielsen 
Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

ext4: fix potential deadlock in ext4_nonda_switch()

2012-10-12T20:50:24+00:00

commit 00d4e7362ed01987183e9528295de3213031309c upstream.

In ext4_nonda_switch(), if the file system is getting full we used to
call writeback_inodes_sb_if_idle().  The problem is that we can be
holding i_mutex already, and this causes a potential deadlock when
writeback_inodes_sb_if_idle() when it tries to take s_umount.  (See
lockdep output below).

As it turns out we don't need need to hold s_umount; the fact that we
are in the middle of the write(2) system call will keep the superblock
pinned.  Unfortunately writeback_inodes_sb() checks to make sure
s_umount is taken, and the VFS uses a different mechanism for making
sure the file system doesn't get unmounted out from under us.  The
simplest way of dealing with this is to just simply grab s_umount
using a trylock, and skip kicking the writeback flusher thread in the
very unlikely case that we can't take a read lock on s_umount without
blocking.

Also, we now check the cirteria for kicking the writeback thread
before we decide to whether to fall back to non-delayed writeback, so
if there are any outstanding delayed allocation writes, we try to get
them resolved as soon as possible.

   [ INFO: possible circular locking dependency detected ]
   3.6.0-rc1-00042-gce894ca #367 Not tainted
   -------------------------------------------------------
   dd/8298 is trying to acquire lock:
    (&type->s_umount_key#18){++++..}, at: [] writeback_inodes_sb_if_idle+0x28/0x46

   but task is already holding lock:
    (&sb->s_type->i_mutex_key#8){+.+...}, at: [] generic_file_aio_write+0x5f/0xd3

   which lock already depends on the new lock.

   2 locks held by dd/8298:
    #0:  (sb_writers#2){.+.+.+}, at: [] generic_file_aio_write+0x56/0xd3
    #1:  (&sb->s_type->i_mutex_key#8){+.+...}, at: [] generic_file_aio_write+0x5f/0xd3

   stack backtrace:
   Pid: 8298, comm: dd Not tainted 3.6.0-rc1-00042-gce894ca #367
   Call Trace:
    [] ? console_unlock+0x345/0x372
    [] print_circular_bug+0x190/0x19d
    [] __lock_acquire+0x86d/0xb6c
    [] ? mark_held_locks+0x5c/0x7b
    [] lock_acquire+0x66/0xb9
    [] ? writeback_inodes_sb_if_idle+0x28/0x46
    [] down_read+0x28/0x58
    [] ? writeback_inodes_sb_if_idle+0x28/0x46
    [] writeback_inodes_sb_if_idle+0x28/0x46
    [] ext4_nonda_switch+0xe1/0xf4
    [] ext4_da_write_begin+0x27/0x193
    [] generic_file_buffered_write+0xc8/0x1bb
    [] __generic_file_aio_write+0x1dd/0x205
    [] generic_file_aio_write+0x78/0xd3
    [] ext4_file_write+0x480/0x4a6
    [] ? __lock_acquire+0x41e/0xb6c
    [] ? sched_clock_cpu+0x11a/0x13e
    [] ? trace_hardirqs_off+0xb/0xd
    [] ? local_clock+0x37/0x4e
    [] do_sync_write+0x67/0x9d
    [] ? wait_on_retry_sync_kiocb+0x44/0x44
    [] vfs_write+0x7b/0xe6
    [] sys_write+0x3b/0x64
    [] syscall_call+0x7/0xb

Signed-off-by: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

ext4: nuke pdflush from comments

2012-08-04T08:15:34+00:00

The pdflush thread is long gone, so this patch removes references to pdflush
from ext4 comments.

Cc: "Theodore Ts'o" 
Cc: Andreas Dilger 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: Al Viro

ext4: nuke write_super from comments

2012-08-04T08:15:33+00:00

The '->write_super' superblock method is gone, and this patch removes all the
references to 'write_super' from ext3.

Cc: "Theodore Ts'o" 
Cc: Andreas Dilger 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: Al Viro

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2012-08-01T17:26:23+00:00

Pull second vfs pile from Al Viro:
 "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the
  deadlock reproduced by xfstests 068), symlink and hardlink restriction
  patches, plus assorted cleanups and fixes.

  Note that another fsfreeze deadlock (emergency thaw one) is *not*
  dealt with - the series by Fernando conflicts a lot with Jan's, breaks
  userland ABI (FIFREEZE semantics gets changed) and trades the deadlock
  for massive vfsmount leak; this is going to be handled next cycle.
  There probably will be another pull request, but that stuff won't be
  in it."

Fix up trivial conflicts due to unrelated changes next to each other in
drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c}

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
  delousing target_core_file a bit
  Documentation: Correct s_umount state for freeze_fs/unfreeze_fs
  fs: Remove old freezing mechanism
  ext2: Implement freezing
  btrfs: Convert to new freezing mechanism
  nilfs2: Convert to new freezing mechanism
  ntfs: Convert to new freezing mechanism
  fuse: Convert to new freezing mechanism
  gfs2: Convert to new freezing mechanism
  ocfs2: Convert to new freezing mechanism
  xfs: Convert to new freezing code
  ext4: Convert to new freezing mechanism
  fs: Protect write paths by sb_start_write - sb_end_write
  fs: Skip atime update on frozen filesystem
  fs: Add freezing handling to mnt_want_write() / mnt_drop_write()
  fs: Improve filesystem freezing handling
  switch the protection of percpu_counter list to spinlock
  nfsd: Push mnt_want_write() outside of i_mutex
  btrfs: Push mnt_want_write() outside of i_mutex
  fat: Push mnt_want_write() outside of i_mutex
  ...

ext4: Convert to new freezing mechanism

2012-07-31T05:45:48+00:00

We remove most of frozen checks since upper layer takes care of blocking all
writes. We have to handle protection in ext4_page_mkwrite() in a special way
because we cannot use generic block_page_mkwrite(). Also we add a freeze
protection to ext4_evict_inode() so that iput() of unlinked inode cannot modify
a frozen filesystem (we cannot easily instrument ext4_journal_start() /
ext4_journal_stop() with freeze protection because we are missing the
superblock pointer in ext4_journal_stop() in nojournal mode).

CC: linux-ext4@vger.kernel.org
CC: "Theodore Ts'o" 
BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa 
Tested-by: Peter M. Petrakis 
Tested-by: Dann Frazier 
Tested-by: Massimo Morana 
Acked-by: "Theodore Ts'o" 
Signed-off-by: Jan Kara 
Signed-off-by: Al Viro

ext4: undo ext4_calc_metadata_amount if we fail to claim space

2012-07-23T04:00:20+00:00

The function ext4_calc_metadata_amount() has side effects, although
it's not obvious from its function name.  So if we fail to claim
space, regardless of whether we retry to claim the space again, or
return an error, we need to undo these side effects.

Otherwise we can end up incorrectly calculating the number of metadata
blocks needed for the operation, which was responsible for an xfstests
failure for test #271 when using an ext2 file system with delalloc
enabled.

Reported-by: Brian Foster 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

ext4: don't let i_reserved_meta_blocks go negative

2012-07-23T03:59:40+00:00

If we hit a condition where we have allocated metadata blocks that
were not appropriately reserved, we risk underflow of
ei->i_reserved_meta_blocks.  In turn, this can throw
sbi->s_dirtyclusters_counter significantly out of whack and undermine
the nondelalloc fallback logic in ext4_nonda_switch().  Warn if this
occurs and set i_allocated_meta_blocks to avoid this problem.

This condition is reproduced by xfstests 270 against ext2 with
delalloc enabled:

Mar 28 08:58:02 localhost kernel: [  171.526344] EXT4-fs (loop1): delayed block allocation failed for inode 14 at logical offset 64486 with max blocks 64 with error -28
Mar 28 08:58:02 localhost kernel: [  171.526346] EXT4-fs (loop1): This should not happen!! Data will be lost

270 ultimately fails with an inconsistent filesystem and requires an
fsck to repair.  The cause of the error is an underflow in
ext4_da_update_reserve_space() due to an unreserved meta block
allocation.

Signed-off-by: Brian Foster 
Signed-off-by: "Theodore Ts'o" 
Cc: stable@vger.kernel.org

ext4: remove unnecessary argument from __ext4_handle_dirty_metadata()

2012-07-23T00:37:31+00:00

The '__ext4_handle_dirty_metadata()' does not need the 'now' argument
anymore and we can kill it.

Signed-off-by: Artem Bityutskiy 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Jan Kara