From: Ronnie Sahlberg <lsahlber@redhat.com>
Date: Tue, 9 Mar 2021 09:07:32 +1000
Subject: [PATCH] cifs: add a function to get a cached dir based on its dentry
Git-commit: 6ef4e9cbe15df691323af007831dab4e70faa1cf
References: bsc#1190317
Patch-mainline: v5.13-rc1

Needed for subsequent patches in the directory caching
series.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/smb2ops.c   | 16 ++++++++++++++++
 fs/cifs/smb2proto.h |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 5864ef600ee9..65d303466581 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -925,6 +925,22 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 	return rc;
 }
 
+int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
+			      struct dentry *dentry,
+			      struct cached_fid **cfid)
+{
+	mutex_lock(&tcon->crfid.fid_mutex);
+	if (tcon->crfid.dentry == dentry) {
+		cifs_dbg(FYI, "found a cached root file handle by dentry\n");
+		*cfid = &tcon->crfid;
+		kref_get(&tcon->crfid.refcount);
+		mutex_unlock(&tcon->crfid.fid_mutex);
+		return 0;
+	}
+	mutex_unlock(&tcon->crfid.fid_mutex);
+	return -ENOENT;
+}
+
 static void
 smb3_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon,
 	      struct cifs_sb_info *cifs_sb)
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 28e8d821103c..a5f87b02cfaf 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -73,6 +73,9 @@ extern int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 			   const char *path,
 			   struct cifs_sb_info *cifs_sb,
 			   struct cached_fid **cfid);
+extern int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
+				     struct dentry *dentry,
+				     struct cached_fid **cfid);
 extern void close_cached_dir(struct cached_fid *cfid);
 extern void close_cached_dir_lease(struct cached_fid *cfid);
 extern void close_cached_dir_lease_locked(struct cached_fid *cfid);
-- 
2.33.0