ext4: Avoid underflow in ext4_trim_fs()

Currently if len argument in ext4_trim_fs() is smaller than one block,
the 'end' variable underflow. Avoid that by returning EINVAL if len is
smaller than file system block.

Also remove useless unlikely().

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index eb1e385d8080e73bd6a5111fa8ff27f772f919f0..f05d08e1336621bb819dc8707d5b999d91a724fe 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4990,8 +4990,9 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
        minlen = EXT4_NUM_B2C(EXT4_SB(sb),
                              range->minlen >> sb->s_blocksize_bits);
 
-       if (unlikely(minlen > EXT4_CLUSTERS_PER_GROUP(sb)) ||
-           unlikely(start >= max_blks))
+       if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
+           start >= max_blks ||
+           range->len < sb->s_blocksize)
                return -EINVAL;
        if (end >= max_blks)
                end = max_blks - 1;