ext4_handle_uniniatilized_extents_split_return_error_fix.patch

   1 ext4: fix uniniatilized extent splitting error
   2
   3 From: Dmitry Monakhov <dmonakhov@openvz.org>
   4
   5 Fix bug reported by Dmitry Monakhov caused by lost error code
   6
   7     Testcase:
   8
   9     blksize = 0x1000;
  10     fd = open(argv[1], O_RDWR|O_CREAT, 0700);
  11     unsigned long long sz = 0x10000000UL;
  12     /* allocating big blocks chunk */
  13     syscall(__NR_fallocate, fd, 0, 0UL, sz)
  14
  15     /* grab all other available filesystem space */
  16     tfd = open("tmp", O_RDWR|O_CREAT|O_DIRECT, 0700);
  17     while( write(tfd, buf, 4096) > 0); /* loop untill ENOSPC */
  18     fsync(fd); /* just in case */
  19     while (pos < sz) {
  20         /* each seek+ write operation result in splits uninitialized extent
  21         in three extents. Splitting may result in new extent allocation
  22         which probably will fail because of ENOSPC*/
  23
  24         lseek(fd, blksize*2 -1, SEEK_CUR);
  25         if ((ret = write(fd, 'a', 1)) != 1)
  26                 exit(1);
  27         pos += blksize * 2;
  28     }
  29
  30 Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
  31 Signed-off-by: Mingming Cao <cmm@us.ibm.com>
  32 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
  33
  34 ---
  35
  36  fs/ext4/extents.c |    5 +++--
  37  1 file changed, 3 insertions(+), 2 deletions(-)
  38
  39
  40 Index: linux-2.6.24-rc7/fs/ext4/extents.c
  41 ===================================================================
  42 --- linux-2.6.24-rc7.orig/fs/ext4/extents.c     2008-01-16 13:52:19.000000000 -0800
  43 +++ linux-2.6.24-rc7/fs/ext4/extents.c  2008-01-16 13:52:34.000000000 -0800
  44 @@ -2373,9 +2373,10 @@ int ext4_ext_get_blocks(handle_t *handle
  45                         ret = ext4_ext_convert_to_initialized(handle, inode,
  46                                                                 path, iblock,
  47                                                                 max_blocks);
  48 -                       if (ret <= 0)
  49 +                       if (ret <= 0) {
  50 +                               err = ret;
  51                                 goto out2;
  52 -                       else
  53 +                       } else
  54                                 allocated = ret;
  55                         goto outnew;
  56                 }