src/patches/suse-2.6.27.31/patches.fixes/ext4-use-a-fake-block-number-for-delayed-new-buffer_head

   1 From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   2 Date: Tue, 12 May 2009 18:40:37 +0000 (-0400)
   3 Subject: ext4: Use a fake block number for delayed new buffer_head
   4 Patch-mainline: 2.6.30-rc6
   5 Git-commit: 33b9817e2ae097c7b8d256e3510ac6c54fc6d9d0
   6 References: bnc#503161
   7
   8 ext4: Use a fake block number for delayed new buffer_head
   9
  10 Use a very large unsigned number (~0xffff) as as the fake block number
  11 for the delayed new buffer. The VFS should never try to write out this
  12 number, but if it does, this will make it obvious.
  13
  14 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
  15 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  16 Acked-by: Jeff Mahoney <jeffm@suse.com>
  17 ---
  18
  19  fs/ext4/inode.c |    6 +++++-
  20  1 file changed, 5 insertions(+), 1 deletion(-)
  21
  22 --- a/fs/ext4/inode.c
  23 +++ b/fs/ext4/inode.c
  24 @@ -2190,6 +2190,10 @@ static int ext4_da_get_block_prep(struct
  25                                   struct buffer_head *bh_result, int create)
  26  {
  27         int ret = 0;
  28 +       sector_t invalid_block = ~((sector_t) 0xffff);
  29 +
  30 +       if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
  31 +               invalid_block = ~0;
  32
  33         BUG_ON(create == 0);
  34         BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
  35 @@ -2211,7 +2215,7 @@ static int ext4_da_get_block_prep(struct
  36                         /* not enough space to reserve */
  37                         return ret;
  38
  39 -               map_bh(bh_result, inode->i_sb, 0);
  40 +               map_bh(bh_result, inode->i_sb, invalid_block);
  41                 set_buffer_new(bh_result);
  42                 set_buffer_delay(bh_result);
  43         } else if (ret > 0) {