ext4_unwritten_extent_delalloc_fix.patch

   1 ext4: Handle unwritten extent properly with delayed allocation
   2
   3 From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   4
   5 When using fallocate the buffer_heads are marked unwritten and unmapped.
   6 We need to map them in the writepages after a get_block.  Otherwise we
   7 split the uninit extents, but never write the content to disk.
   8
   9 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
  10 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  11 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  12 ---
  13  fs/ext4/inode.c |   12 ++++++++++--
  14  1 file changed, 10 insertions(+), 2 deletions(-)
  15
  16 Index: linux-2.6.27-rc1/fs/ext4/inode.c
  17 ===================================================================
  18 --- linux-2.6.27-rc1.orig/fs/ext4/inode.c       2008-08-11 14:27:43.000000000 -0700
  19 +++ linux-2.6.27-rc1/fs/ext4/inode.c    2008-08-11 14:27:48.000000000 -0700
  20 @@ -1720,6 +1720,13 @@ static void mpage_put_bnr_to_bhs(struct
  21                                 if (buffer_delay(bh)) {
  22                                         bh->b_blocknr = pblock;
  23                                         clear_buffer_delay(bh);
  24 +                                       bh->b_bdev = inode->i_sb->s_bdev;
  25 +                               } else if (buffer_unwritten(bh)) {
  26 +                                       bh->b_blocknr = pblock;
  27 +                                       clear_buffer_unwritten(bh);
  28 +                                       set_buffer_mapped(bh);
  29 +                                       set_buffer_new(bh);
  30 +                                       bh->b_bdev = inode->i_sb->s_bdev;
  31                                 } else if (buffer_mapped(bh))
  32                                         BUG_ON(bh->b_blocknr != pblock);
  33
  34 @@ -1793,7 +1800,7 @@ static void mpage_da_map_blocks(struct m
  35                  * If blocks are delayed marked, we need to
  36                  * put actual blocknr and drop delayed bit
  37                  */
  38 -               if (buffer_delay(lbh))
  39 +               if (buffer_delay(lbh) || buffer_unwritten(lbh))
  40                         mpage_put_bnr_to_bhs(mpd, next, &new);
  41
  42                 /* go for the remaining blocks */
  43 @@ -1802,7 +1809,8 @@ static void mpage_da_map_blocks(struct m
  44         }
  45  }
  46
  47 -#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | (1 << BH_Delay))
  48 +#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
  49 +               (1 << BH_Delay) | (1 << BH_Unwritten))
  50
  51  /*
  52   * mpage_add_bh_to_extent - try to add one more block to extent of blocks