update-mtime-in-ext4_punch_hole-even-if-no-blocks-removed

   1 ext4: update mtime in ext4_punch_hole even if no blocks are released
   2
   3 From: Lukas Czerner <lczerner@redhat.com>
   4
   5 Currently in ext4_punch_hole we're going to skip the mtime update if
   6 there are no actual blocks to release. However we've actually modified
   7 the file by zeroing the partial block so the mtime should be updated.
   8
   9 Moreover the sync and datasync handling is skipped as well, which is
  10 also wrong. Fix it.
  11
  12 Signed-off-by: Lukas Czerner <lczerner@redhat.com>
  13 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  14 Reported-by: Joe Habermann <joe.habermann@quantum.com>
  15 Cc: <stable@vger.kernel.org>
  16 ---
  17  fs/ext4/inode.c | 36 ++++++++++++++++++------------------
  18  1 file changed, 18 insertions(+), 18 deletions(-)
  19
  20 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  21 index 1e50c5e..6b4c5c0 100644
  22 --- a/fs/ext4/inode.c
  23 +++ b/fs/ext4/inode.c
  24 @@ -4298,28 +4298,28 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
  25                 EXT4_BLOCK_SIZE_BITS(sb);
  26         stop_block = (offset + length) >> EXT4_BLOCK_SIZE_BITS(sb);
  27
  28 -       /* If there are no blocks to remove, return now */
  29 -       if (first_block >= stop_block)
  30 -               goto out_stop;
  31 +       /* If there are blocks to remove, do it */
  32 +       if (stop_block > first_block) {
  33
  34 -       down_write(&EXT4_I(inode)->i_data_sem);
  35 -       ext4_discard_preallocations(inode);
  36 +               down_write(&EXT4_I(inode)->i_data_sem);
  37 +               ext4_discard_preallocations(inode);
  38
  39 -       ret = ext4_es_remove_extent(inode, first_block,
  40 -                                   stop_block - first_block);
  41 -       if (ret) {
  42 -               up_write(&EXT4_I(inode)->i_data_sem);
  43 -               goto out_stop;
  44 -       }
  45 +               ret = ext4_es_remove_extent(inode, first_block,
  46 +                                           stop_block - first_block);
  47 +               if (ret) {
  48 +                       up_write(&EXT4_I(inode)->i_data_sem);
  49 +                       goto out_stop;
  50 +               }
  51
  52 -       if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
  53 -               ret = ext4_ext_remove_space(inode, first_block,
  54 -                                           stop_block - 1);
  55 -       else
  56 -               ret = ext4_ind_remove_space(handle, inode, first_block,
  57 -                                           stop_block);
  58 +               if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
  59 +                       ret = ext4_ext_remove_space(inode, first_block,
  60 +                                                   stop_block - 1);
  61 +               else
  62 +                       ret = ext4_ind_remove_space(handle, inode, first_block,
  63 +                                                   stop_block);
  64
  65 -       up_write(&EXT4_I(inode)->i_data_sem);
  66 +               up_write(&EXT4_I(inode)->i_data_sem);
  67 +       }
  68         if (IS_SYNC(inode))
  69                 ext4_handle_sync(handle);
  70
  71 --
  72 2.7.5
  73
  74