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Add more critical-section calls: all code sections that hold spinlocks

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are now critical sections, so as to ensure die() won't interrupt us while
we are munging shared-memory data structures.  Avoid insecure intermediate
states in some code that proc_exit will call, like palloc/pfree.  Rename
START/END_CRIT_CODE to START/END_CRIT_SECTION, since that seems to be
what people tend to call them anyway, and make them be called with () like
a function call, in hopes of not confusing pg_indent.
I doubt that this is sufficient to make SIGTERM safe anywhere; there's
just too much code that could get invoked during proc_exit().
This commit is contained in:
Tom Lane
2001-01-12 21:54:01 +00:00
parent be8477bc37
commit 6162432de9
17 changed files with 163 additions and 129 deletions
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45
src/backend/storage/buffer/bufmgr.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.102 2001/01/08 18:31:49 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/buffer/bufmgr.c,v 1.103 2001/01/12 21:53:57 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -404,8 +404,7 @@ BufferAlloc(Relation reln,
*/
if ((buf->flags & BM_IO_ERROR) != 0)
{
PrivateRefCount[BufferDescriptorGetBuffer(buf) - 1] = 0;
buf->refcount--;
UnpinBuffer(buf);
buf = (BufferDesc *) NULL;
continue;
}
@ -869,8 +868,10 @@ WaitIO(BufferDesc *buf, SPINLOCK spinlock)
while ((buf->flags & BM_IO_IN_PROGRESS) != 0)
{
SpinRelease(spinlock);
START_CRIT_SECTION(); /* don't want to die() holding the lock... */
S_LOCK(&(buf->io_in_progress_lock));
S_UNLOCK(&(buf->io_in_progress_lock));
END_CRIT_SECTION();
SpinAcquire(spinlock);
}
}
@ -921,14 +922,11 @@ ResetBufferUsage()
* ResetBufferPool
*
* This routine is supposed to be called when a transaction aborts.
* it will release all the buffer pins held by the transaction.
* It will release all the buffer pins held by the transaction.
* Currently, we also call it during commit if BufferPoolCheckLeak
* detected a problem --- in that case, isCommit is TRUE, and we
* only clean up buffer pin counts.
*
* During abort, we also forget any pending fsync requests. Dirtied buffers
* will still get written, eventually, but there will be no fsync for them.
*
* ----------------------------------------------
*/
void
@ -943,6 +941,7 @@ ResetBufferPool(bool isCommit)
BufferDesc *buf = &BufferDescriptors[i];
SpinAcquire(BufMgrLock);
PrivateRefCount[i] = 0;
Assert(buf->refcount > 0);
buf->refcount--;
if (buf->refcount == 0)
@ -952,7 +951,6 @@ ResetBufferPool(bool isCommit)
}
SpinRelease(BufMgrLock);
}
PrivateRefCount[i] = 0;
}
ResetLocalBufferPool();
@ -1900,7 +1898,7 @@ SetBufferCommitInfoNeedsSave(Buffer buffer)
}
void
UnlockBuffers()
UnlockBuffers(void)
{
BufferDesc *buf;
int i;
@ -1913,6 +1911,8 @@ UnlockBuffers()
Assert(BufferIsValid(i + 1));
buf = &(BufferDescriptors[i]);
START_CRIT_SECTION(); /* don't want to die() holding the lock... */
S_LOCK(&(buf->cntx_lock));
if (BufferLocks[i] & BL_R_LOCK)
@ -1940,6 +1940,8 @@ UnlockBuffers()
S_UNLOCK(&(buf->cntx_lock));
BufferLocks[i] = 0;
END_CRIT_SECTION();
}
}
@ -1956,6 +1958,8 @@ LockBuffer(Buffer buffer, int mode)
buf = &(BufferDescriptors[buffer - 1]);
buflock = &(BufferLocks[buffer - 1]);
START_CRIT_SECTION(); /* don't want to die() holding the lock... */
S_LOCK(&(buf->cntx_lock));
if (mode == BUFFER_LOCK_UNLOCK)
@ -1979,6 +1983,7 @@ LockBuffer(Buffer buffer, int mode)
else
{
S_UNLOCK(&(buf->cntx_lock));
END_CRIT_SECTION();
elog(ERROR, "UNLockBuffer: buffer %lu is not locked", buffer);
}
}
@ -1990,7 +1995,9 @@ LockBuffer(Buffer buffer, int mode)
while (buf->ri_lock || buf->w_lock)
{
S_UNLOCK(&(buf->cntx_lock));
END_CRIT_SECTION();
S_LOCK_SLEEP(&(buf->cntx_lock), i++);
START_CRIT_SECTION();
S_LOCK(&(buf->cntx_lock));
}
(buf->r_locks)++;
@ -2016,7 +2023,9 @@ LockBuffer(Buffer buffer, int mode)
buf->ri_lock = true;
}
S_UNLOCK(&(buf->cntx_lock));
END_CRIT_SECTION();
S_LOCK_SLEEP(&(buf->cntx_lock), i++);
START_CRIT_SECTION();
S_LOCK(&(buf->cntx_lock));
}
buf->w_lock = true;
@ -2038,10 +2047,12 @@ LockBuffer(Buffer buffer, int mode)
else
{
S_UNLOCK(&(buf->cntx_lock));
END_CRIT_SECTION();
elog(ERROR, "LockBuffer: unknown lock mode %d", mode);
}
S_UNLOCK(&(buf->cntx_lock));
END_CRIT_SECTION();
}
/*
@ -2062,7 +2073,9 @@ static bool IsForInput;
* BM_IO_IN_PROGRESS mask is not set for the buffer
* The buffer is Pinned
*
*/
* Because BufMgrLock is held, we are already in a CRIT_SECTION here,
* and do not need another.
*/
static void
StartBufferIO(BufferDesc *buf, bool forInput)
{
@ -2094,7 +2107,9 @@ StartBufferIO(BufferDesc *buf, bool forInput)
* BufMgrLock is held
* The buffer is Pinned
*
*/
* Because BufMgrLock is held, we are already in a CRIT_SECTION here,
* and do not need another.
*/
static void
TerminateBufferIO(BufferDesc *buf)
{
@ -2110,7 +2125,9 @@ TerminateBufferIO(BufferDesc *buf)
* BufMgrLock is held
* The buffer is Pinned
*
*/
* Because BufMgrLock is held, we are already in a CRIT_SECTION here,
* and do not need another.
*/
static void
ContinueBufferIO(BufferDesc *buf, bool forInput)
{
@ -2132,7 +2149,7 @@ InitBufferIO(void)
* This function is called from ProcReleaseSpins().
* BufMgrLock isn't held when this function is called.
*
* If I/O was in progress, BM_IO_ERROR is always set.
* If I/O was in progress, we always set BM_IO_ERROR.
*/
void
AbortBufferIO(void)
@ -2141,8 +2158,8 @@ AbortBufferIO(void)
if (buf)
{
Assert(buf->flags & BM_IO_IN_PROGRESS);
SpinAcquire(BufMgrLock);
Assert(buf->flags & BM_IO_IN_PROGRESS);
if (IsForInput)
Assert(!(buf->flags & BM_DIRTY) && !(buf->cntxDirty));
else