ceph: ensure d_name stability in ceph_dentry_hash()

Take the d_lock here to ensure that d_name doesn't change. Cc: [email protected] Signed-off-by: Jeff Layton <[email protected]> Reviewed-by: "Yan, Zheng" <[email protected]> Signed-off-by: Ilya Dryomov <[email protected]>
chewitt · Apr 23, 2019 · 76a495d · 76a495d
1 parent 1bcb344
commit 76a495d
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
@@ -1766,15 +1766,19 @@ static ssize_t ceph_read_dir(struct file *file, char __user *buf, size_t size,
 unsigned ceph_dentry_hash(struct inode *dir, struct dentry *dn)
 {
 	struct ceph_inode_info *dci = ceph_inode(dir);
+	unsigned hash;
 
 	switch (dci->i_dir_layout.dl_dir_hash) {
 	case 0:	/* for backward compat */
 	case CEPH_STR_HASH_LINUX:
 		return dn->d_name.hash;
 
 	default:
-		return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
+		spin_lock(&dn->d_lock);
+		hash = ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
 				     dn->d_name.name, dn->d_name.len);
+		spin_unlock(&dn->d_lock);
+		return hash;
 	}
 }