src/patches/suse-2.6.27.25/patches.suse/xfs-wait-for-all-IO-on-truncate-to-zero

   1 From: Lachlan McIlroy <lachlan@sgi.com>
   2 Subject: [XFS] Wait for all I/O on truncate to zero file size
   3 Patch-mainline: ?
   4 References: bnc#450658
   5
   6 It's possible to have outstanding xfs_ioend_t's queued when the file size
   7 is zero. This can happen in the direct I/O path when a direct I/O write
   8 fails due to ENOSPC. In this case the xfs_ioend_t will still be queued (ie
   9 xfs_end_io_direct() does not know that the I/O failed so can't force the
  10 xfs_ioend_t to be flushed synchronously).
  11
  12 When we truncate a file on unlink we don't know to wait for these
  13 xfs_ioend_ts and we can have a use-after-free situation if the inode is
  14 reclaimed before the xfs_ioend_t is finally processed.
  15
  16 As was suggested by Dave Chinner lets wait for all I/Os to complete when
  17 truncating the file size to zero.
  18
  19 SGI-PV: 981668
  20
  21 SGI-Modid: xfs-linux-melb:xfs-kern:32216a
  22
  23 Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
  24 Signed-off-by: Christoph Hellwig <hch@infradead.org>
  25 Acked-by: Jan Kara <jack@suse.cz>
  26
  27 Index: linux-2.6.27.5-2/fs/xfs/xfs_inode.c
  28 ===================================================================
  29 --- linux-2.6.27.5-2.orig/fs/xfs/xfs_inode.c    2008-12-03 11:58:00.992733026 +1100
  30 +++ linux-2.6.27.5-2/fs/xfs/xfs_inode.c 2008-12-03 11:59:17.542975042 +1100
  31 @@ -1414,7 +1414,7 @@ xfs_itruncate_start(
  32         mp = ip->i_mount;
  33
  34         /* wait for the completion of any pending DIOs */
  35 -       if (new_size < ip->i_size)
  36 +       if (new_size == 0 || new_size < ip->i_size)
  37                 vn_iowait(ip);
  38
  39         /*