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  1. 23 Nov, 2009 4 commits
    • Akira Fujita's avatar
      ext4: fix lock order problem in ext4_move_extents() · fc04cb49
      Akira Fujita authored 
      ext4_move_extents() checks the logical block contiguousness
of original file with ext4_find_extent() and mext_next_extent().
Therefore the extent which ext4_ext_path structure indicates
must not be changed between above functions.

But in current implementation, there is no i_data_sem protection
between ext4_ext_find_extent() and mext_next_extent().  So the extent
which ext4_ext_path structure indicates may be overwritten by
delalloc.  As a result, ext4_move_extents() will exchange wrong blocks
between original and donor files.  I change the place where
acquire/release i_data_sem to solve this problem.

Moreover, I changed move_extent_per_page() to start transaction first,
and then acquire i_data_sem.  Without this change, there is a
possibility of the deadlock between mmap() and ext4_move_extents():

* NOTE: "A", "B" and "C" mean different processes

A-1: ext4_ext_move_extents() acquires i_data_sem of two inodes.

B:   do_page_fault() starts the transaction (T),
     and then tries to acquire i_data_sem.
     But process "A" is already holding it, so it is kept waiting.

C:   While "A" and "B" running, kjournald2 tries to commit transaction (T)
     but it is under updating, so kjournald2 waits for it.

A-2: Call ext4_journal_start with holding i_data_sem,
     but transaction (T) is locked.
Signed-off-by: default avatarAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      fc04cb49
    • Akira Fujita's avatar
      ext4: fix the returned block count if EXT4_IOC_MOVE_EXT fails · f868a48d
      Akira Fujita authored 
      If the EXT4_IOC_MOVE_EXT ioctl fails, the number of blocks that were
exchanged before the failure should be returned to the userspace
caller.  Unfortunately, currently if the block size is not the same as
the page size, the returned block count that is returned is the
page-aligned block count instead of the actual block count.  This
commit addresses this bug.
Signed-off-by: default avatarAkira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      f868a48d
    • Theodore Ts'o's avatar
      ext4: avoid divide by zero when trying to mount a corrupted file system · 503358ae
      Theodore Ts'o authored 
      If s_log_groups_per_flex is greater than 31, then groups_per_flex will
will overflow and cause a divide by zero error.  This can cause kernel
BUG if such a file system is mounted.

Thanks to Nageswara R Sastry for analyzing the failure and providing
an initial patch.

http://bugzilla.kernel.org/show_bug.cgi?id=14287Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
      503358ae
    • Theodore Ts'o's avatar
      ext4: fix potential buffer head leak when add_dirent_to_buf() returns ENOSPC · 2de770a4
      Theodore Ts'o authored 
      Previously add_dirent_to_buf() did not free its passed-in buffer head
in the case of ENOSPC, since in some cases the caller still needed it.
However, this led to potential buffer head leaks since not all callers
dealt with this correctly.  Fix this by making simplifying the freeing
convention; now add_dirent_to_buf() *never* frees the passed-in buffer
head, and leaves that to the responsibility of its caller.  This makes
things cleaner and easier to prove that the code is neither leaking
buffer heads or calling brelse() one time too many.
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: Curt Wohlgemuth <curtw@google.com>
Cc: stable@kernel.org
      2de770a4
  3. 13 Nov, 2009 1 commit
  5. 12 Nov, 2009 35 commits
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