From 961f9a03d4c27220c33e88402d5ef274424a0ab2 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 17 Mar 2021 07:12:35 +0900 Subject: [PATCH] Revert "Remove HAVE_WORKING_LINK" This reverts commit aaa3aeddee51dd0058d38469907865052706a590. --- src/include/pg_config_manual.h | 7 +++++++ src/include/storage/fd.h | 2 +- src/backend/access/transam/timeline.c | 4 ++-- src/backend/access/transam/xlog.c | 4 ++-- src/backend/storage/file/fd.c | 21 ++++++++++++++++----- 5 files changed, 28 insertions(+), 10 deletions(-) diff --git a/src/include/pg_config_manual.h b/src/include/pg_config_manual.h index 8f3ec6bde1..966da99742 100644 --- a/src/include/pg_config_manual.h +++ b/src/include/pg_config_manual.h @@ -135,6 +135,13 @@ #define EXEC_BACKEND #endif +/* + * Define this if your operating system supports link() + */ +#if !defined(WIN32) && !defined(__CYGWIN__) +#define HAVE_WORKING_LINK 1 +#endif + /* * USE_POSIX_FADVISE controls whether Postgres will attempt to use the * posix_fadvise() kernel call. Usually the automatic configure tests are diff --git a/src/include/storage/fd.h b/src/include/storage/fd.h index 8cd125d7df..2085c62b41 100644 --- a/src/include/storage/fd.h +++ b/src/include/storage/fd.h @@ -157,7 +157,7 @@ extern void fsync_fname(const char *fname, bool isdir); extern int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel); extern int durable_rename(const char *oldfile, const char *newfile, int loglevel); extern int durable_unlink(const char *fname, int loglevel); -extern int durable_rename_excl(const char *oldfile, const char *newfile, int loglevel); +extern int durable_link_or_rename(const char *oldfile, const char *newfile, int loglevel); extern void SyncDataDirectory(void); extern int data_sync_elevel(int elevel); diff --git a/src/backend/access/transam/timeline.c b/src/backend/access/transam/timeline.c index e6a29d9a9b..27d70ff869 100644 --- a/src/backend/access/transam/timeline.c +++ b/src/backend/access/transam/timeline.c @@ -446,7 +446,7 @@ writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI, * Perform the rename using link if available, paranoidly trying to avoid * overwriting an existing file (there shouldn't be one). */ - durable_rename_excl(tmppath, path, ERROR); + durable_link_or_rename(tmppath, path, ERROR); /* The history file can be archived immediately. */ if (XLogArchivingActive()) @@ -524,7 +524,7 @@ writeTimeLineHistoryFile(TimeLineID tli, char *content, int size) * Perform the rename using link if available, paranoidly trying to avoid * overwriting an existing file (there shouldn't be one). */ - durable_rename_excl(tmppath, path, ERROR); + durable_link_or_rename(tmppath, path, ERROR); } /* diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 7daa7c43ad..82e070e431 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -3624,11 +3624,11 @@ InstallXLogFileSegment(XLogSegNo *segno, char *tmppath, * Perform the rename using link if available, paranoidly trying to avoid * overwriting an existing file (there shouldn't be one). */ - if (durable_rename_excl(tmppath, path, LOG) != 0) + if (durable_link_or_rename(tmppath, path, LOG) != 0) { if (use_lock) LWLockRelease(ControlFileLock); - /* durable_rename_excl already emitted log message */ + /* durable_link_or_rename already emitted log message */ return false; } diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c index e5950b0726..ba92ceaf65 100644 --- a/src/backend/storage/file/fd.c +++ b/src/backend/storage/file/fd.c @@ -767,11 +767,10 @@ durable_unlink(const char *fname, int elevel) } /* - * durable_rename_excl -- rename a file in a durable manner, without - * overwriting an existing target file + * durable_link_or_rename -- rename a file in a durable manner. * - * Similar to durable_rename(), except that this routine will fail if the - * target file already exists. + * Similar to durable_rename(), except that this routine tries (but does not + * guarantee) not to overwrite the target file. * * Note that a crash in an unfortunate moment can leave you with two links to * the target file. @@ -782,7 +781,7 @@ durable_unlink(const char *fname, int elevel) * valid upon return. */ int -durable_rename_excl(const char *oldfile, const char *newfile, int elevel) +durable_link_or_rename(const char *oldfile, const char *newfile, int elevel) { /* * Ensure that, if we crash directly after the rename/link, a file with @@ -791,6 +790,7 @@ durable_rename_excl(const char *oldfile, const char *newfile, int elevel) if (fsync_fname_ext(oldfile, false, false, elevel) != 0) return -1; +#ifdef HAVE_WORKING_LINK if (link(oldfile, newfile) < 0) { ereport(elevel, @@ -800,6 +800,17 @@ durable_rename_excl(const char *oldfile, const char *newfile, int elevel) return -1; } unlink(oldfile); +#else + /* XXX: Add racy file existence check? */ + if (rename(oldfile, newfile) < 0) + { + ereport(elevel, + (errcode_for_file_access(), + errmsg("could not rename file \"%s\" to \"%s\": %m", + oldfile, newfile))); + return -1; + } +#endif /* * Make change persistent in case of an OS crash, both the new entry and -- 2.30.2