cifs: Grab a reference for the dentry of the cached directory during the lifetime of the cache

We need to hold both a reference for the root/superblock as well as the directory that we
are caching. We need to drop these references before we call kill_anon_sb().

At this point, the root and the cached dentries are always the same but this will change
once we start caching other directories as well.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index cf8eceb1d5a5..4257f841ec4e 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -257,11 +257,28 @@ out_no_root:
 static void cifs_kill_sb(struct super_block *sb)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	struct cifs_tcon *tcon;
+	struct cached_fid *cfid;
 
+	/*
+	 * We ned to release all dentries for the cached directories
+	 * before we kill the sb.
+	 */
 	if (cifs_sb->root) {
 		dput(cifs_sb->root);
 		cifs_sb->root = NULL;
 	}
+	tcon = cifs_sb_master_tcon(cifs_sb);
+	if (tcon) {
+		cfid = &tcon->crfid;
+		mutex_lock(&cfid->fid_mutex);
+		if (cfid->dentry) {
+
+			dput(cfid->dentry);
+			cfid->dentry = NULL;
+		}
+		mutex_unlock(&cfid->fid_mutex);
+	}
 
 	kill_anon_super(sb);
 	cifs_umount(cifs_sb);