To: PostgreSQL-development <pgsql-hackers@postgresql.org>
From: Maksim Milyutin <milyutinma@gmail.com>
Subject: Hint to set owner for tablespace directory
Message-ID: <5ca60e1a-26f9-89fd-e912-021dd2b8afe2@gmail.com>
Date: Thu, 23 Aug 2018 14:24:25 +0300
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Hi!


I have noticed the novice users are stuck trying to create tablespace 
over a directory whose owner is not the system postgres user. They 
observed the message "could not set permissions on directory ...: 
permission denied".

I want to add patch that prints hint to set required owner for the 
tablespace directory if this is the cause of the problem (*errno == 
EPERM* after calling *chmod*).


-- 
Regards,
Maksim Milyutin


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diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index f7e9160..a8733d4 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -585,10 +585,16 @@ create_tablespace_directories(const char *location, const Oid tablespaceoid)
 					 InRecovery ? errhint("Create this directory for the tablespace before "
 										  "restarting the server.") : 0));
 		else
+		{
+			bool wrong_owner = (errno == EPERM);
+
 			ereport(ERROR,
 					(errcode_for_file_access(),
 					 errmsg("could not set permissions on directory \"%s\": %m",
-							location)));
+							location),
+					 wrong_owner ? errhint("Install the PostgreSQL system user as "
+										   "the owner of this directory.") : 0));
+		}
 	}
 
 	if (InRecovery)

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