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Avoid unlikely data-loss scenarios due to rename() without fsync.
Renaming a file using rename(2) is not guaranteed to be durable in face of crashes. Use the previously added durable_rename()/durable_link_or_rename() in various places where we previously just renamed files. Most of the changed call sites are arguably not critical, but it seems better to err on the side of too much durability. The most prominent known case where the previously missing fsyncs could cause data loss is crashes at the end of a checkpoint. After the actual checkpoint has been performed, old WAL files are recycled. When they're filled, their contents are fdatasynced, but we did not fsync the containing directory. An OS/hardware crash in an unfortunate moment could then end up leaving that file with its old name, but new content; WAL replay would thus not replay it. Reported-By: Tomas Vondra Author: Michael Paquier, Tomas Vondra, Andres Freund Discussion: 56583BDD.9060302@2ndquadrant.com Backpatch: All supported branches
This commit is contained in:
Andres Freund
parent
c224d44f77
commit
ce8f42919d
@ -588,11 +588,7 @@ pgss_shmem_shutdown(int code, Datum arg)
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/*
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* Rename file into place, so we atomically replace the old one.
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*/
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if (rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE) != 0)
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ereport(LOG,
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(errcode_for_file_access(),
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errmsg("could not rename pg_stat_statement file \"%s\": %m",
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PGSS_DUMP_FILE ".tmp")));
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(void) durable_rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE, LOG);
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return;
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@ -1380,12 +1380,7 @@ XLogArchiveForceDone(const char *xlog)
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StatusFilePath(archiveReady, xlog, ".ready");
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if (stat(archiveReady, &stat_buf) == 0)
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{
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if (rename(archiveReady, archiveDone) < 0)
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ereport(WARNING,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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archiveReady, archiveDone)));
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(void) durable_rename(archiveReady, archiveDone, WARNING);
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return;
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}
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@ -2773,34 +2768,16 @@ InstallXLogFileSegment(uint32 *log, uint32 *seg, char *tmppath,
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}
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/*
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* Prefer link() to rename() here just to be really sure that we don't
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* overwrite an existing logfile. However, there shouldn't be one, so
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* rename() is an acceptable substitute except for the truly paranoid.
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* Perform the rename using link if available, paranoidly trying to avoid
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* overwriting an existing file (there shouldn't be one).
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*/
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#if HAVE_WORKING_LINK
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if (link(tmppath, path) < 0)
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if (durable_link_or_rename(tmppath, path, LOG) != 0)
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{
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if (use_lock)
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LWLockRelease(ControlFileLock);
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ereport(LOG,
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(errcode_for_file_access(),
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errmsg("could not link file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
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tmppath, path, *log, *seg)));
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/* durable_link_or_rename already emitted log message */
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return false;
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}
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unlink(tmppath);
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#else
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if (rename(tmppath, path) < 0)
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{
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if (use_lock)
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LWLockRelease(ControlFileLock);
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ereport(LOG,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\" (initialization of log file %u, segment %u): %m",
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tmppath, path, *log, *seg)));
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return false;
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}
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#endif
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if (use_lock)
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LWLockRelease(ControlFileLock);
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@ -3048,11 +3025,7 @@ KeepFileRestoredFromArchive(char *path, char *xlogfname)
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reload = true;
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}
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if (rename(path, xlogfpath) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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path, xlogfpath)));
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durable_rename(path, xlogfpath, ERROR);
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/*
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* Create .done file forcibly to prevent the restored segment from
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@ -4882,24 +4855,10 @@ writeTimeLineHistory(TimeLineID newTLI, TimeLineID parentTLI,
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TLHistoryFilePath(path, newTLI);
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/*
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* Prefer link() to rename() here just to be really sure that we don't
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* overwrite an existing logfile. However, there shouldn't be one, so
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* rename() is an acceptable substitute except for the truly paranoid.
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* Perform the rename using link if available, paranoidly trying to avoid
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* overwriting an existing file (there shouldn't be one).
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*/
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#if HAVE_WORKING_LINK
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if (link(tmppath, path) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not link file \"%s\" to \"%s\": %m",
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tmppath, path)));
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unlink(tmppath);
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#else
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if (rename(tmppath, path) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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tmppath, path)));
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#endif
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durable_link_or_rename(tmppath, path, ERROR);
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/* The history file can be archived immediately. */
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if (XLogArchivingActive())
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@ -5882,11 +5841,7 @@ exitArchiveRecovery(TimeLineID endTLI, uint32 endLogId, uint32 endLogSeg)
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* re-enter archive recovery mode in a subsequent crash.
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*/
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unlink(RECOVERY_COMMAND_DONE);
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if (rename(RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE) != 0)
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ereport(FATAL,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE)));
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durable_rename(RECOVERY_COMMAND_FILE, RECOVERY_COMMAND_DONE, FATAL);
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ereport(LOG,
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(errmsg("archive recovery complete")));
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@ -6795,11 +6750,7 @@ StartupXLOG(void)
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if (haveBackupLabel)
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{
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unlink(BACKUP_LABEL_OLD);
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if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) != 0)
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ereport(FATAL,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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BACKUP_LABEL_FILE, BACKUP_LABEL_OLD)));
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durable_rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD, FATAL);
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}
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/* Check that the GUCs used to generate the WAL allow recovery */
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@ -10486,7 +10437,7 @@ CancelBackup(void)
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/* remove leftover file from previously canceled backup if it exists */
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unlink(BACKUP_LABEL_OLD);
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if (rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD) == 0)
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if (durable_rename(BACKUP_LABEL_FILE, BACKUP_LABEL_OLD, DEBUG1) == 0)
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{
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ereport(LOG,
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(errmsg("online backup mode canceled"),
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@ -749,9 +749,5 @@ pgarch_archiveDone(char *xlog)
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StatusFilePath(rlogready, xlog, ".ready");
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StatusFilePath(rlogdone, xlog, ".done");
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if (rename(rlogready, rlogdone) < 0)
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ereport(WARNING,
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(errcode_for_file_access(),
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errmsg("could not rename file \"%s\" to \"%s\": %m",
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rlogready, rlogdone)));
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(void) durable_rename(rlogready, rlogdone, WARNING);
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}
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