ext3/ext3_truncate_block_allocated_on_a_failed_ext3_write_begin.patch

   1 ext3: truncate block allocated on a failed ext3_write_begin
   2
   3 From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
   4
   5 For blocksize < pagesize we need to remove blocks that got allocated in
   6 block_write_begin() if we fail with ENOSPC for later blocks.
   7 block_write_begin() internally does this if it allocated page
   8 locally. This makes sure we don't have blocks outside inode.i_size
   9 during ENOSPC.
  10
  11 Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
  12 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  13 Cc: linux-ext4@vger.kernel.org
  14 ---
  15  fs/ext3/inode.c |    7 +++++++
  16  1 files changed, 7 insertions(+), 0 deletions(-)
  17
  18 Index: linux-2.6.27-rc5/fs/ext3/inode.c
  19 ===================================================================
  20 --- linux-2.6.27-rc5.orig/fs/ext3/inode.c       2008-08-28 23:25:04.000000000 -0700
  21 +++ linux-2.6.27-rc5/fs/ext3/inode.c    2008-08-28 23:28:48.000000000 -0700
  22 @@ -1178,6 +1178,13 @@ write_begin_failed:
  23                 ext3_journal_stop(handle);
  24                 unlock_page(page);
  25                 page_cache_release(page);
  26 +               /*
  27 +                * block_write_begin may have instantiated a few blocks
  28 +                * outside i_size.  Trim these off again. Don't need
  29 +                * i_size_read because we hold i_mutex.
  30 +                */
  31 +               if (pos + len > inode->i_size)
  32 +                       vmtruncate(inode, inode->i_size);
  33         }
  34         if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
  35                 goto retry;