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| author | Peter Eisentraut <peter@eisentraut.org> | 2020-03-26 11:51:39 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2020-03-26 13:29:20 +0100 |
| commit | 49bf81536e242f079bfbce6e8f95f53f18207dd5 (patch) | |
| tree | 04134155d85d1ee8f85faa22ad23d09292a38c5f | |
| parent | 958aa438aaa473d580f60154786ffd716a28faf2 (diff) | |
| download | postgresql-49bf81536e242f079bfbce6e8f95f53f18207dd5.tar.gz postgresql-49bf81536e242f079bfbce6e8f95f53f18207dd5.zip | |
Drop slot's LWLock before returning from SaveSlotToPath()
When SaveSlotToPath() is called with elevel=LOG, the early exits didn't
release the slot's io_in_progress_lock.
This could result in a walsender being stuck on the lock forever. A
possible way to get into this situation is if the offending code paths
are triggered in a low disk space situation.
Author: Pavan Deolasee <pavan.deolasee@2ndquadrant.com>
Reported-by: Craig Ringer <craig@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/56a138c5-de61-f553-7e8f-6789296de785%402ndquadrant.com
| -rw-r--r-- | src/backend/replication/slot.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c index 1cec53d7484..d90c7235e98 100644 --- a/src/backend/replication/slot.c +++ b/src/backend/replication/slot.c @@ -1256,6 +1256,12 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) fd = OpenTransientFile(tmppath, O_CREAT | O_EXCL | O_WRONLY | PG_BINARY); if (fd < 0) { + /* + * If not an ERROR, then release the lock before returning. In case + * of an ERROR, the error recovery path automatically releases the + * lock, but no harm in explicitly releasing even in that case. + */ + LWLockRelease(&slot->io_in_progress_lock); ereport(elevel, (errcode_for_file_access(), errmsg("could not create file \"%s\": %m", @@ -1287,6 +1293,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) pgstat_report_wait_end(); CloseTransientFile(fd); + LWLockRelease(&slot->io_in_progress_lock); /* if write didn't set errno, assume problem is no disk space */ errno = save_errno ? save_errno : ENOSPC; @@ -1306,6 +1313,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) pgstat_report_wait_end(); CloseTransientFile(fd); + LWLockRelease(&slot->io_in_progress_lock); errno = save_errno; ereport(elevel, (errcode_for_file_access(), @@ -1317,6 +1325,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) if (CloseTransientFile(fd) != 0) { + LWLockRelease(&slot->io_in_progress_lock); ereport(elevel, (errcode_for_file_access(), errmsg("could not close file \"%s\": %m", @@ -1327,6 +1336,7 @@ SaveSlotToPath(ReplicationSlot *slot, const char *dir, int elevel) /* rename to permanent file, fsync file and directory */ if (rename(tmppath, path) != 0) { + LWLockRelease(&slot->io_in_progress_lock); ereport(elevel, (errcode_for_file_access(), errmsg("could not rename file \"%s\" to \"%s\": %m", |