replace-bogus-assertion-in-ext4_xattr_shift_entries

   1 ext4: replace bogus assertion in ext4_xattr_shift_entries()
   2
   3 From: Jan Kara <jack@suse.cz>
   4
   5 We were checking whether computed offsets do not exceed end of block in
   6 ext4_xattr_shift_entries(). However this does not make sense since we
   7 always only decrease offsets. So replace that assertion with a check
   8 whether we really decrease xattrs value offsets.
   9
  10 Signed-off-by: Jan Kara <jack@suse.cz>
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/ext4/xattr.c | 9 +++++----
  14  1 file changed, 5 insertions(+), 4 deletions(-)
  15
  16 diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
  17 index 1447860b61ec..82b025c977fc 100644
  18 --- a/fs/ext4/xattr.c
  19 +++ b/fs/ext4/xattr.c
  20 @@ -1319,18 +1319,19 @@ retry:
  21   */
  22  static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry,
  23                                      int value_offs_shift, void *to,
  24 -                                    void *from, size_t n, int blocksize)
  25 +                                    void *from, size_t n)
  26  {
  27         struct ext4_xattr_entry *last = entry;
  28         int new_offs;
  29
  30 +       /* We always shift xattr headers further thus offsets get lower */
  31 +       BUG_ON(value_offs_shift > 0);
  32 +
  33         /* Adjust the value offsets of the entries */
  34         for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
  35                 if (last->e_value_size) {
  36                         new_offs = le16_to_cpu(last->e_value_offs) +
  37                                                         value_offs_shift;
  38 -                       BUG_ON(new_offs + le32_to_cpu(last->e_value_size)
  39 -                                > blocksize);
  40                         last->e_value_offs = cpu_to_le16(new_offs);
  41                 }
  42         }
  43 @@ -1542,7 +1543,7 @@ shift:
  44         ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
  45                         - new_extra_isize, (void *)raw_inode +
  46                         EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize,
  47 -                       (void *)header, total_ino, inode->i_sb->s_blocksize);
  48 +                       (void *)header, total_ino);
  49         EXT4_I(inode)->i_extra_isize = new_extra_isize;
  50         brelse(bh);
  51  out:
  52 --
  53 2.6.6
  54
  55