cifs: Do not access tcon->cfids->cfid directly from is_path_accessible

cfids will soon keep a list of cached fids so we should not access this
directly from outside of cached_dir.c
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cached_dir.c

@@ -16,9 +16,9 @@
  * If error then *cfid is not initialized.
  */
 int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
-		const char *path,
-		struct cifs_sb_info *cifs_sb,
-		struct cached_fid **ret_cfid)
+		    const char *path,
+		    struct cifs_sb_info *cifs_sb,
+		    bool lookup_only, struct cached_fid **ret_cfid)
 {
 	struct cifs_ses *ses;
 	struct TCP_Server_Info *server;
@@ -68,9 +68,11 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon,
 	 * cifs_mark_open_files_invalid() which takes the lock again
 	 * thus causing a deadlock
 	 */
-
 	mutex_unlock(&cfid->fid_mutex);
 
+	if (lookup_only)
+		return -ENOENT;
+
 	if (smb3_encryption_required(tcon))
 		flags |= CIFS_TRANSFORM_REQ;
 

fs/cifs/cached_dir.h

@@ -50,7 +50,7 @@ extern void free_cached_dir(struct cifs_tcon *tcon);
 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);
+			   bool lookup_only, struct cached_fid **cfid);
 extern int open_cached_dir_by_dentry(struct cifs_tcon *tcon,
 				     struct dentry *dentry,
 				     struct cached_fid **cfid);

fs/cifs/readdir.c

@@ -1072,7 +1072,7 @@ int cifs_readdir(struct file *file, struct dir_context *ctx)
 		tcon = tlink_tcon(cifsFile->tlink);
 	}
 
-	rc = open_cached_dir(xid, tcon, full_path, cifs_sb, &cfid);
+	rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
 	cifs_put_tlink(tlink);
 	if (rc)
 		goto cache_not_found;
@@ -1143,7 +1143,7 @@ int cifs_readdir(struct file *file, struct dir_context *ctx)
 	tcon = tlink_tcon(cifsFile->tlink);
 	rc = find_cifs_entry(xid, tcon, ctx->pos, file, full_path,
 			     &current_entry, &num_to_fill);
-	open_cached_dir(xid, tcon, full_path, cifs_sb, &cfid);
+	open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
 	if (rc) {
 		cifs_dbg(FYI, "fce error %d\n", rc);
 		goto rddir2_exit;

fs/cifs/smb2inode.c

@@ -516,7 +516,7 @@ smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 	if (strcmp(full_path, ""))
 		rc = -ENOENT;
 	else
-		rc = open_cached_dir(xid, tcon, full_path, cifs_sb, &cfid);
+		rc = open_cached_dir(xid, tcon, full_path, cifs_sb, false, &cfid);
 	/* If it is a root and its handle is cached then use it */
 	if (!rc) {
 		if (cfid->file_all_info_is_valid) {

fs/cifs/smb2ops.c

@@ -720,7 +720,7 @@ smb3_qfs_tcon(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = open_cached_dir(xid, tcon, "", cifs_sb, &cfid);
+	rc = open_cached_dir(xid, tcon, "", cifs_sb, false, &cfid);
 	if (rc == 0)
 		memcpy(&fid, &cfid->fid, sizeof(struct cifs_fid));
 	else
@@ -783,9 +783,16 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
 	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct cifs_open_parms oparms;
 	struct cifs_fid fid;
+	struct cached_fid *cfid;
 
-	if ((*full_path == 0) && tcon->cfid->is_valid)
-		return 0;
+	rc = open_cached_dir(xid, tcon, full_path, cifs_sb, true, &cfid);
+	if (!rc) {
+		if (cfid->is_valid) {
+			close_cached_dir(cfid);
+			return 0;
+		}
+		close_cached_dir(cfid);
+	}
 
 	utf16_path = cifs_convert_path_to_utf16(full_path, cifs_sb);
 	if (!utf16_path)
@@ -2430,8 +2437,12 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	resp_buftype[0] = resp_buftype[1] = resp_buftype[2] = CIFS_NO_BUFFER;
 	memset(rsp_iov, 0, sizeof(rsp_iov));
 
+	/*
+	 * We can only call this for things we know are directories.
+	 */
 	if (!strcmp(path, ""))
-		open_cached_dir(xid, tcon, path, cifs_sb, &cfid); /* cfid null if open dir failed */
+		open_cached_dir(xid, tcon, path, cifs_sb, false,
+				&cfid); /* cfid null if open dir failed */
 
 	memset(&open_iov, 0, sizeof(open_iov));
 	rqst[0].rq_iov = open_iov;