btrfs: Return EINVAL when length to trim is less than FSB

Currently if len argument in btrfs_ioctl_fitrim() is smaller than
one FSB we will continue and finally return 0 bytes discarded.
However if the length to discard is smaller then file system block
we should really return EINVAL.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f5a2e6c4320a..da518ded34bd 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -343,7 +343,8 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
                 return -EOPNOTSUPP;
         if (copy_from_user(&range, arg, sizeof(range)))
                 return -EFAULT;
-        if (range.start > total_bytes)
+        if (range.start > total_bytes ||
+            range.len < fs_info->sb->s_blocksize)
                 return -EINVAL;
 
         range.len = min(range.len, total_bytes - range.start);