From: Shyam Prasad N <sprasad@microsoft.com>
Date: Fri, 1 Apr 2022 06:25:17 +0000
Subject: [PATCH] cifs: release cached dentries only if mount is complete
Git-commit: d788e51636462e61c6883f7d96b07b06bc291650
References: bsc#1190317
Patch-mainline: v5.18-rc2

During cifs_kill_sb, we first dput all the dentries that we have cached.
However this function can also get called for mount failures.
So dput the cached dentries only if the filesystem mount is complete.
i.e. cifs_sb->root is populated.

Fixes: 5e9c89d43fa6 ("cifs: Grab a reference for the dentry of the cached directory during the lifetime of the cache")
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifsfs.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index fb60b5410789..aba0783a8f09 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -266,22 +266,24 @@ static void cifs_kill_sb(struct super_block *sb)
 	 * before we kill the sb.
 	 */
 	if (cifs_sb->root) {
+		node = rb_first(root);
+		while (node != NULL) {
+			tlink = rb_entry(node, struct tcon_link, tl_rbnode);
+			tcon = tlink_tcon(tlink);
+			cfid = &tcon->crfid;
+			mutex_lock(&cfid->fid_mutex);
+			if (cfid->dentry) {
+				dput(cfid->dentry);
+				cfid->dentry = NULL;
+			}
+			mutex_unlock(&cfid->fid_mutex);
+			node = rb_next(node);
+		}
+
+		/* finally release root dentry */
 		dput(cifs_sb->root);
 		cifs_sb->root = NULL;
 	}
-	node = rb_first(root);
-	while (node != NULL) {
-		tlink = rb_entry(node, struct tcon_link, tl_rbnode);
-		tcon = tlink_tcon(tlink);
-		cfid = &tcon->crfid;
-		mutex_lock(&cfid->fid_mutex);
-		if (cfid->dentry) {
-			dput(cfid->dentry);
-			cfid->dentry = NULL;
-		}
-		mutex_unlock(&cfid->fid_mutex);
-		node = rb_next(node);
-	}
 
 	kill_anon_super(sb);
 	cifs_umount(cifs_sb);
-- 
2.35.3