diff options
| -rw-r--r-- | src/backend/commands/tablespace.c | 54 | ||||
| -rw-r--r-- | src/include/storage/lwlock.h | 3 |
2 files changed, 27 insertions, 30 deletions
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c index f83d1ab8843..19955dd81ed 100644 --- a/src/backend/commands/tablespace.c +++ b/src/backend/commands/tablespace.c @@ -37,7 +37,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.28 2005/10/15 02:49:15 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.29 2006/01/19 04:45:38 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -83,12 +83,9 @@ static void set_short_version(const char *path); * If tablespaces are not supported, this is just a no-op; CREATE DATABASE * is expected to create the default subdirectory for the database. * - * isRedo indicates that we are creating an object during WAL replay; - * we can skip doing locking in that case (and should do so to avoid - * any possible problems with pg_tablespace not being valid). - * - * Also, when isRedo is true, we will cope with the possibility of the - * tablespace not being there either --- this could happen if we are + * isRedo indicates that we are creating an object during WAL replay. + * In this case we will cope with the possibility of the tablespace + * directory not being there either --- this could happen if we are * replaying an operation on a table in a subsequently-dropped tablespace. * We handle this by making a directory in the place where the tablespace * symlink would normally be. This isn't an exact replay of course, but @@ -118,16 +115,10 @@ TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo) if (errno == ENOENT) { /* - * Acquire ExclusiveLock on pg_tablespace to ensure that no DROP - * TABLESPACE or TablespaceCreateDbspace is running concurrently. - * Simple reads from pg_tablespace are OK. + * Acquire TablespaceCreateLock to ensure that no DROP TABLESPACE + * or TablespaceCreateDbspace is running concurrently. */ - Relation rel; - - if (!isRedo) - rel = heap_open(TableSpaceRelationId, ExclusiveLock); - else - rel = NULL; + LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE); /* * Recheck to see if someone created the directory while we were @@ -166,9 +157,7 @@ TablespaceCreateDbspace(Oid spcNode, Oid dbNode, bool isRedo) } } - /* OK to drop the exclusive lock */ - if (!isRedo) - heap_close(rel, ExclusiveLock); + LWLockRelease(TablespaceCreateLock); } else { @@ -402,14 +391,10 @@ DropTableSpace(DropTableSpaceStmt *stmt) PreventTransactionChain((void *) stmt, "DROP TABLESPACE"); /* - * Acquire ExclusiveLock on pg_tablespace to ensure that no one else is - * trying to do DROP TABLESPACE or TablespaceCreateDbspace concurrently. - */ - rel = heap_open(TableSpaceRelationId, ExclusiveLock); - - /* * Find the target tuple */ + rel = heap_open(TableSpaceRelationId, RowExclusiveLock); + ScanKeyInit(&entry[0], Anum_pg_tablespace_spcname, BTEqualStrategyNumber, F_NAMEEQ, @@ -449,6 +434,12 @@ DropTableSpace(DropTableSpaceStmt *stmt) deleteSharedDependencyRecordsFor(TableSpaceRelationId, tablespaceoid); /* + * Acquire TablespaceCreateLock to ensure that no TablespaceCreateDbspace + * is running concurrently. + */ + LWLockAcquire(TablespaceCreateLock, LW_EXCLUSIVE); + + /* * Try to remove the physical infrastructure */ if (!remove_tablespace_directories(tablespaceoid, false)) @@ -471,6 +462,11 @@ DropTableSpace(DropTableSpaceStmt *stmt) (void) XLogInsert(RM_TBLSPC_ID, XLOG_TBLSPC_DROP, rdata); } + /* + * Allow TablespaceCreateDbspace again. + */ + LWLockRelease(TablespaceCreateLock); + /* We keep the lock on pg_tablespace until commit */ heap_close(rel, NoLock); #else /* !HAVE_SYMLINK */ @@ -507,10 +503,10 @@ remove_tablespace_directories(Oid tablespaceoid, bool redo) * use the tablespace from that database will simply recreate the * subdirectory via TablespaceCreateDbspace.) * - * Since we hold exclusive lock, no one else should be creating any fresh - * subdirectories in parallel. It is possible that new files are being - * created within subdirectories, though, so the rmdir call could fail. - * Worst consequence is a less friendly error message. + * Since we hold TablespaceCreateLock, no one else should be creating any + * fresh subdirectories in parallel. It is possible that new files are + * being created within subdirectories, though, so the rmdir call could + * fail. Worst consequence is a less friendly error message. */ dirdesc = AllocateDir(location); if (dirdesc == NULL) diff --git a/src/include/storage/lwlock.h b/src/include/storage/lwlock.h index ca384218a50..fb05544db1f 100644 --- a/src/include/storage/lwlock.h +++ b/src/include/storage/lwlock.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.25 2006/01/04 21:06:32 tgl Exp $ + * $PostgreSQL: pgsql/src/include/storage/lwlock.h,v 1.26 2006/01/19 04:45:38 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -46,6 +46,7 @@ typedef enum LWLockId RelCacheInitLock, BgWriterCommLock, TwoPhaseStateLock, + TablespaceCreateLock, FirstLockMgrLock, /* must be last except for MaxDynamicLWLock */ MaxDynamicLWLock = 1000000000 |