vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/sysv/itree.c b/fs/sysv/itree.c
index fa8d43c..90b54b4 100644
--- a/fs/sysv/itree.c
+++ b/fs/sysv/itree.c
@@ -442,7 +442,7 @@
 
 int sysv_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
 {
-	struct super_block *s = mnt->mnt_sb;
+	struct super_block *s = dentry->d_sb;
 	generic_fillattr(dentry->d_inode, stat);
 	stat->blocks = (s->s_blocksize / 512) * sysv_nblocks(s, stat->size);
 	stat->blksize = s->s_blocksize;