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

1 files changed, 3 insertions, 2 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index eb1e385d8080..f05d08e13366 100644
--- 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;