From 943228b5d4e0dc42ad219c3fe97adb59e7262593 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Fri, 1 Apr 2022 17:02:51 +1300 Subject: [PATCH 1/2] WIP: Rethink PROCSIGNAL_BARRIER_SMGRRELEASE. Commit 4eb21763 closed kernel file descriptors, but left SMgrRelations in existence. Unfortunately, IssuePendingWritebacks() can reopen them at any time, including right before the a file is unlinked. In order for IssuePendingWritebacks() to be able to avoid this hazard in a later commit, go further and close the SMgrRelations. XXX We had better make sure that no code does: reln = smgropen(...); CHECK_FOR_INTERRUPTS(); smgrXXX(reln, ...); --- src/backend/storage/smgr/md.c | 6 ------ src/backend/storage/smgr/smgr.c | 10 ++-------- src/include/storage/md.h | 1 - 3 files changed, 2 insertions(+), 15 deletions(-) diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c index 879f647dbc..d26c915f90 100644 --- a/src/backend/storage/smgr/md.c +++ b/src/backend/storage/smgr/md.c @@ -549,12 +549,6 @@ mdclose(SMgrRelation reln, ForkNumber forknum) } } -void -mdrelease(void) -{ - closeAllVfds(); -} - /* * mdprefetch() -- Initiate asynchronous read of the specified block of a relation */ diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c index efa83ae394..994728db04 100644 --- a/src/backend/storage/smgr/smgr.c +++ b/src/backend/storage/smgr/smgr.c @@ -41,7 +41,6 @@ typedef struct f_smgr { void (*smgr_init) (void); /* may be NULL */ void (*smgr_shutdown) (void); /* may be NULL */ - void (*smgr_release) (void); /* may be NULL */ void (*smgr_open) (SMgrRelation reln); void (*smgr_close) (SMgrRelation reln, ForkNumber forknum); void (*smgr_create) (SMgrRelation reln, ForkNumber forknum, @@ -70,7 +69,6 @@ static const f_smgr smgrsw[] = { { .smgr_init = mdinit, .smgr_shutdown = NULL, - .smgr_release = mdrelease, .smgr_open = mdopen, .smgr_close = mdclose, .smgr_create = mdcreate, @@ -717,17 +715,13 @@ AtEOXact_SMgr(void) } /* - * This routine is called when we are ordered to release all open files by a + * This routine is called when we are ordered to close all SMgrRelations by a * ProcSignalBarrier. */ bool ProcessBarrierSmgrRelease(void) { - for (int i = 0; i < NSmgr; i++) - { - if (smgrsw[i].smgr_release) - smgrsw[i].smgr_release(); - } + smgrcloseall(); return true; } diff --git a/src/include/storage/md.h b/src/include/storage/md.h index 6e46d8d96a..ffffa40db7 100644 --- a/src/include/storage/md.h +++ b/src/include/storage/md.h @@ -23,7 +23,6 @@ extern void mdinit(void); extern void mdopen(SMgrRelation reln); extern void mdclose(SMgrRelation reln, ForkNumber forknum); -extern void mdrelease(void); extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo); extern bool mdexists(SMgrRelation reln, ForkNumber forknum); extern void mdunlink(RelFileNodeBackend rnode, ForkNumber forknum, bool isRedo); -- 2.35.1