1 files changed, 49 insertions, 4 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 0cdc4e47ca87..a5bc1b671c12 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -694,8 +694,51 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
 
 	smb2_set_related(&rqst[1]);
 
+	/*
+	 * We do not hold the lock for the open because in case
+	 * SMB2_open needs to reconnect, it will end up calling
+	 * cifs_mark_open_files_invalid() which takes the lock again
+	 * thus causing a deadlock
+	 */
+
+	mutex_unlock(&tcon->crfid.fid_mutex);
 	rc = compound_send_recv(xid, ses, flags, 2, rqst,
 				resp_buftype, rsp_iov);
+	mutex_lock(&tcon->crfid.fid_mutex);
+
+	/*
+	 * Now we need to check again as the cached root might have
+	 * been successfully re-opened from a concurrent process
+	 */
+
+	if (tcon->crfid.is_valid) {
+		/* work was already done */
+
+		/* stash fids for close() later */
+		struct cifs_fid fid = {
+			.persistent_fid = pfid->persistent_fid,
+			.volatile_fid = pfid->volatile_fid,
+		};
+
+		/*
+		 * caller expects this func to set pfid to a valid
+		 * cached root, so we copy the existing one and get a
+		 * reference.
+		 */
+		memcpy(pfid, tcon->crfid.fid, sizeof(*pfid));
+		kref_get(&tcon->crfid.refcount);
+
+		mutex_unlock(&tcon->crfid.fid_mutex);
+
+		if (rc == 0) {
+			/* close extra handle outside of crit sec */
+			SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+		}
+		goto oshr_free;
+	}
+
+	/* Cached root is still invalid, continue normaly */
+
 	if (rc)
 		goto oshr_exit;
 
@@ -711,11 +754,12 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
 	tcon->crfid.is_valid = true;
 	kref_init(&tcon->crfid.refcount);
 
+	/* BB TBD check to see if oplock level check can be removed below */
 	if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
 		kref_get(&tcon->crfid.refcount);
-		oplock = smb2_parse_lease_state(server, o_rsp,
-						&oparms.fid->epoch,
-						oparms.fid->lease_key);
+		smb2_parse_contexts(server, o_rsp,
+				&oparms.fid->epoch,
+				oparms.fid->lease_key, &oplock, NULL);
 	} else
 		goto oshr_exit;
 
@@ -729,8 +773,9 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
 				(char *)&tcon->crfid.file_all_info))
 		tcon->crfid.file_all_info_is_valid = 1;
 
- oshr_exit:
+oshr_exit:
 	mutex_unlock(&tcon->crfid.fid_mutex);
+oshr_free:
 	SMB2_open_free(&rqst[0]);
 	SMB2_query_info_free(&rqst[1]);
 	free_rsp_buf(resp_buftype[0], rsp_iov[0].iov_base);