[PATCH] cifs: use the cached root handle for readdir() if possible

[PATCH] cifs: use the cached root handle for readdir() if possible

[Ronnie Sahlberg]

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
---
 fs/cifs/smb2ops.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 4c0922596467..7aab18552dd8 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -681,7 +681,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
 
 	oparms.tcon = tcon;
 	oparms.create_options = 0;
-	oparms.desired_access = FILE_READ_ATTRIBUTES;
+	oparms.desired_access = FILE_READ_ATTRIBUTES | FILE_READ_DATA;
 	oparms.disposition = FILE_OPEN;
 	oparms.fid = pfid;
 	oparms.reconnect = false;
@@ -1999,6 +1999,14 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc;
 	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct cifs_open_parms oparms;
+	bool no_cached_open = tcon->nohandlecache;
+
+	if (!strlen(path) && !no_cached_open) {
+		rc = open_shroot(xid, tcon, fid);
+		if (rc)
+			return rc;
+		goto after_open;
+	}
 
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path)
@@ -2021,6 +2029,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 		return rc;
 	}
 
+ after_open:
 	srch_inf->entries_in_buffer = 0;
 	srch_inf->index_of_last_entry = 2;
 
@@ -2046,6 +2055,13 @@ static int
 smb2_close_dir(const unsigned int xid, struct cifs_tcon *tcon,
 	       struct cifs_fid *fid)
 {
+	if (tcon->crfid.is_valid &&
+	    tcon->crfid.fid->persistent_fid == fid->persistent_fid &&
+	    tcon->crfid.fid->volatile_fid == fid->volatile_fid) {
+		close_shroot(&tcon->crfid);
+		return 0;
+	}
+
 	return SMB2_close(xid, tcon, fid->persistent_fid, fid->volatile_fid);
 }
 
-- 
2.13.6