1. 08 Nov, 2010 2 commits
    • Theodore Ts'o's avatar
      ext4: fix potential race when freeing ext4_io_page structures · 83668e71
      Theodore Ts'o authored
      Use an atomic_t and make sure we don't free the structure while we
      might still be submitting I/O for that page.
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      83668e71
    • Theodore Ts'o's avatar
      ext4: handle writeback of inodes which are being freed · f7ad6d2e
      Theodore Ts'o authored
      The following BUG can occur when an inode which is getting freed when
      it still has dirty pages outstanding, and it gets deleted (in this
      because it was the target of a rename).  In ordered mode, we need to
      make sure the data pages are written just in case we crash before the
      rename (or unlink) is committed.  If the inode is being freed then
      when we try to igrab the inode, we end up tripping the BUG_ON at
      fs/ext4/page-io.c:146.
      
      To solve this problem, we need to keep track of the number of io
      callbacks which are pending, and avoid destroying the inode until they
      have all been completed.  That way we don't have to bump the inode
      count to keep the inode from being destroyed; an approach which
      doesn't work because the count could have already been dropped down to
      zero before the inode writeback has started (at which point we're not
      allowed to bump the count back up to 1, since it's already started
      getting freed).
      
      Thanks to Dave Chinner for suggesting this approach, which is also
      used by XFS.
      
        kernel BUG at /scratch_space/linux-2.6/fs/ext4/page-io.c:146!
        Call Trace:
         [<ffffffff811075b1>] ext4_bio_write_page+0x172/0x307
         [<ffffffff811033a7>] mpage_da_submit_io+0x2f9/0x37b
         [<ffffffff811068d7>] mpage_da_map_and_submit+0x2cc/0x2e2
         [<ffffffff811069b3>] mpage_add_bh_to_extent+0xc6/0xd5
         [<ffffffff81106c66>] write_cache_pages_da+0x2a4/0x3ac
         [<ffffffff81107044>] ext4_da_writepages+0x2d6/0x44d
         [<ffffffff81087910>] do_writepages+0x1c/0x25
         [<ffffffff810810a4>] __filemap_fdatawrite_range+0x4b/0x4d
         [<ffffffff810815f5>] filemap_fdatawrite_range+0xe/0x10
         [<ffffffff81122a2e>] jbd2_journal_begin_ordered_truncate+0x7b/0xa2
         [<ffffffff8110615d>] ext4_evict_inode+0x57/0x24c
         [<ffffffff810c14a3>] evict+0x22/0x92
         [<ffffffff810c1a3d>] iput+0x212/0x249
         [<ffffffff810bdf16>] dentry_iput+0xa1/0xb9
         [<ffffffff810bdf6b>] d_kill+0x3d/0x5d
         [<ffffffff810be613>] dput+0x13a/0x147
         [<ffffffff810b990d>] sys_renameat+0x1b5/0x258
         [<ffffffff81145f71>] ? _atomic_dec_and_lock+0x2d/0x4c
         [<ffffffff810b2950>] ? cp_new_stat+0xde/0xea
         [<ffffffff810b29c1>] ? sys_newlstat+0x2d/0x38
         [<ffffffff810b99c6>] sys_rename+0x16/0x18
         [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b
      Reported-by: default avatarNick Bowler <nbowler@elliptictech.com>
      Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
      Tested-by: default avatarNick Bowler <nbowler@elliptictech.com>
      f7ad6d2e
  2. 03 Nov, 2010 1 commit
  3. 02 Nov, 2010 2 commits
  4. 01 Nov, 2010 10 commits
  5. 31 Oct, 2010 14 commits
  6. 30 Oct, 2010 11 commits