From ca347f5433ed036ae82cc0939d235b2bda9b77fe Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 27 Jul 2022 07:55:12 +0200 Subject: Allow "in place" tablespaces. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a backpatch to branches 10-14 of the following commits: 7170f2159fb2 Allow "in place" tablespaces. c6f2f01611d4 Fix pg_basebackup with in-place tablespaces. f6f0db4d6240 Fix pg_tablespace_location() with in-place tablespaces 7a7cd84893e0 doc: Remove mention to in-place tablespaces for pg_tablespace_location() 5344723755bd Remove unnecessary Windows-specific basebackup code. In-place tablespaces were introduced as a testing helper mechanism, but they are going to be used for a bugfix in WAL replay to be backpatched to all stable branches. I (Álvaro) had to adjust some code to account for lack of get_dirent_type() in branches prior to 14. Author: Thomas Munro Author: Michaël Paquier Author: Álvaro Herrera Discussion: https://postgr.es/m/20220722081858.omhn2in5zt3g4nek@alvherre.pgsql --- src/backend/utils/adt/misc.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'src/backend/utils/adt/misc.c') diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c index 1f081cc6318..aae175e07b6 100644 --- a/src/backend/utils/adt/misc.c +++ b/src/backend/utils/adt/misc.c @@ -15,6 +15,7 @@ #include "postgres.h" #include +#include #include #include #include @@ -307,6 +308,9 @@ pg_tablespace_location(PG_FUNCTION_ARGS) char sourcepath[MAXPGPATH]; char targetpath[MAXPGPATH]; int rllen; +#ifndef WIN32 + struct stat st; +#endif /* * It's useful to apply this function to pg_class.reltablespace, wherein @@ -331,6 +335,31 @@ pg_tablespace_location(PG_FUNCTION_ARGS) */ snprintf(sourcepath, sizeof(sourcepath), "pg_tblspc/%u", tablespaceOid); + /* + * Before reading the link, check if the source path is a link or a + * junction point. Note that a directory is possible for a tablespace + * created with allow_in_place_tablespaces enabled. If a directory is + * found, a relative path to the data directory is returned. + */ +#ifdef WIN32 + if (!pgwin32_is_junction(sourcepath)) + PG_RETURN_TEXT_P(cstring_to_text(sourcepath)); +#else + if (lstat(sourcepath, &st) < 0) + { + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + sourcepath))); + } + + if (!S_ISLNK(st.st_mode)) + PG_RETURN_TEXT_P(cstring_to_text(sourcepath)); +#endif + + /* + * In presence of a link or a junction point, return the path pointing to. + */ rllen = readlink(sourcepath, targetpath, sizeof(targetpath)); if (rllen < 0) ereport(ERROR, -- cgit v1.2.3