afs: Fix afs_statfs() to not let the values go below zero

Fix afs_statfs() so that the value for f_bavail and f_bfree don't go
"negative" if the number of blocks in use by a volume exceeds the max quota
for that volume.

Signed-off-by: David Howells <dhowells@redhat.com>

diff --git a/fs/afs/super.c b/fs/afs/super.c
index c77b11b..b552357 100644 (file)
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -729,7 +729,10 @@ static void afs_get_volume_status_success(struct afs_operation *op)
                buf->f_blocks = vs->part_max_blocks;
        else
                buf->f_blocks = vs->max_quota;
-       buf->f_bavail = buf->f_bfree = buf->f_blocks - vs->blocks_in_use;
+
+       if (buf->f_blocks > vs->blocks_in_use)
+               buf->f_bavail = buf->f_bfree =
+                       buf->f_blocks - vs->blocks_in_use;
 }
 
 static const struct afs_operation_ops afs_get_volume_status_operation = {