/* set this to 1 when we are terminating to prevent access attempts */
static int buf_ShutdownFlag = 0;
+void buf_HoldLocked(cm_buf_t *bp)
+{
+ osi_assert(bp->magic == CM_BUF_MAGIC);
+ bp->refCount++;
+}
+
/* hold a reference to an already held buffer */
void buf_Hold(cm_buf_t *bp)
{
+ lock_ObtainWrite(&buf_globalLock);
+ buf_HoldLocked(bp);
+ lock_ReleaseWrite(&buf_globalLock);
+}
+
+/* code to drop reference count while holding buf_globalLock */
+void buf_ReleaseLocked(cm_buf_t *bp)
+{
+ /* ensure that we're in the LRU queue if our ref count is 0 */
osi_assert(bp->magic == CM_BUF_MAGIC);
+ osi_assert(bp->refCount > 0);
+ if (--bp->refCount == 0) {
+ if (!(bp->flags & CM_BUF_INLRU)) {
+ osi_QAdd((osi_queue_t **) &cm_data.buf_freeListp, &bp->q);
+
+ /* watch for transition from empty to one element */
+ if (!cm_data.buf_freeListEndp)
+ cm_data.buf_freeListEndp = cm_data.buf_freeListp;
+ bp->flags |= CM_BUF_INLRU;
+ }
+ }
+}
+
+/* release a buffer. Buffer must be referenced, but unlocked. */
+void buf_Release(cm_buf_t *bp)
+{
lock_ObtainWrite(&buf_globalLock);
- bp->refCount++;
+ buf_ReleaseLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
}
lock_ObtainWrite(&buf_globalLock);
bp = cm_data.buf_allp;
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
nAtOnce = (long)sqrt((double)cm_data.buf_nbuffers);
while (buf_ShutdownFlag == 0) {
* and so can be followed even when holding no locks.
*/
lock_ObtainWrite(&buf_globalLock);
- buf_LockedRelease(bp);
+ buf_ReleaseLocked(bp);
bp = bp->allp;
if (!bp)
bp = cm_data.buf_allp;
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
} /* for loop over a bunch of buffers */
} /* whole daemon's while loop */
return CM_ERROR_INVAL;
}
-/* release a buffer. Buffer must be referenced, but unlocked. */
-void buf_Release(cm_buf_t *bp)
-{
- lock_ObtainWrite(&buf_globalLock);
- buf_LockedRelease(bp);
- lock_ReleaseWrite(&buf_globalLock);
-}
-
/* wait for reading or writing to clear; called with write-locked
* buffer and unlocked scp and returns with locked buffer.
*/
osi_Log1(afsd_logp, "WaitIO finished wait for bp 0x%p", bp);
}
-/* code to drop reference count while holding buf_globalLock */
-void buf_LockedRelease(cm_buf_t *bp)
-{
- /* ensure that we're in the LRU queue if our ref count is 0 */
- osi_assert(bp->refCount > 0);
- if (--bp->refCount == 0) {
- if (!(bp->flags & CM_BUF_INLRU)) {
- osi_QAdd((osi_queue_t **) &cm_data.buf_freeListp, &bp->q);
-
- /* watch for transition from empty to one element */
- if (!cm_data.buf_freeListEndp)
- cm_data.buf_freeListEndp = cm_data.buf_freeListp;
- bp->flags |= CM_BUF_INLRU;
- }
- }
-}
-
/* find a buffer, if any, for a particular file ID and offset. Assumes
* that buf_globalLock is write locked when called.
*/
-cm_buf_t *buf_LockedFind(struct cm_scache *scp, osi_hyper_t *offsetp)
+cm_buf_t *buf_FindLocked(struct cm_scache *scp, osi_hyper_t *offsetp)
{
long i;
cm_buf_t *bp;
if (cm_FidCmp(&scp->fid, &bp->fid) == 0
&& offsetp->LowPart == bp->offset.LowPart
&& offsetp->HighPart == bp->offset.HighPart) {
- bp->refCount++;
+ buf_HoldLocked(bp);
break;
}
}
cm_buf_t *bp;
lock_ObtainWrite(&buf_globalLock);
- bp = buf_LockedFind(scp, offsetp);
+ bp = buf_FindLocked(scp, offsetp);
lock_ReleaseWrite(&buf_globalLock);
return bp;
* at any given time, and also ensures that the log is forced sufficiently far,
* if this buffer contains logged data.
*/
-void buf_LockedCleanAsync(cm_buf_t *bp, cm_req_t *reqp)
+void buf_CleanAsyncLocked(cm_buf_t *bp, cm_req_t *reqp)
{
long code = 0;
while ((bp->flags & CM_BUF_DIRTY) == CM_BUF_DIRTY) {
lock_ReleaseMutex(&bp->mx);
- osi_Log1(afsd_logp, "buf_LockedCleanAsync starts I/O on 0x%p", bp);
+ osi_Log1(afsd_logp, "buf_CleanAsyncLocked starts I/O on 0x%p", bp);
code = (*cm_buf_opsp->Writep)(&bp->fid, &bp->offset,
cm_data.buf_blockSize, 0, bp->userp,
reqp);
- osi_Log2(afsd_logp, "buf_LockedCleanAsync I/O on 0x%p, done=%d", bp, code);
+ osi_Log2(afsd_logp, "buf_CleanAsyncLocked I/O on 0x%p, done=%d", bp, code);
lock_ObtainMutex(&bp->mx);
if (code)
lock_ObtainWrite(&buf_globalLock);
/* check to see if we lost the race */
if (scp) {
- if (bp = buf_LockedFind(scp, offsetp)) {
+ if (bp = buf_FindLocked(scp, offsetp)) {
+ /* Do not call buf_ReleaseLocked() because we
+ * do not want to allow the buffer to be added
+ * to the free list.
+ */
bp->refCount--;
lock_ReleaseWrite(&buf_globalLock);
return CM_BUF_EXISTS;
* just the lock required to minimize contention
* on the big lock.
*/
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
/* grab required lock and clean; this only
osi_assert(bp->magic == CM_BUF_MAGIC);
lock_ObtainMutex(&bp->mx);
- buf_LockedCleanAsync(bp, reqp);
+ buf_CleanAsyncLocked(bp, reqp);
lock_ReleaseMutex(&bp->mx);
}
for(i=0; i<cm_data.buf_hashSize; i++) {
for(bp = cm_data.buf_hashTablepp[i]; bp; bp = bp->hashp) {
if ((bp->flags & CM_BUF_DIRTY) == CM_BUF_DIRTY) {
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
/* now no locks are held; clean buffer and go on */
/* relock and release buffer */
lock_ObtainWrite(&buf_globalLock);
- buf_LockedRelease(bp);
+ buf_ReleaseLocked(bp);
} /* dirty */
} /* over one bucket */
} /* for loop over all hash buckets */
osi_hyper_t bufEnd;
long code;
long bufferPos;
- int didRelease;
long i;
/* assert that cm_bufCreateLock is held in write mode */
return 0;
}
- bufp->refCount++;
+ buf_HoldLocked(bufp);
lock_ReleaseWrite(&buf_globalLock);
for(; bufp; bufp = nbufp) {
- didRelease = 0;
lock_ObtainMutex(&bufp->mx);
bufEnd.HighPart = 0;
| CM_SCACHESYNC_GETSTATUS
| CM_SCACHESYNC_SETSIZE
| CM_SCACHESYNC_BUFLOCKED);
- /* if we succeeded in our locking, and this applies to the right
+
+
+ lock_ObtainWrite(&buf_globalLock);
+ /* if we succeeded in our locking, and this applies to the right
* file, and the truncate request overlaps the buffer either
* totally or partially, then do something.
*/
if (code == 0 && cm_FidCmp(&bufp->fid, &scp->fid) == 0
&& LargeIntegerLessThan(*sizep, bufEnd)) {
- lock_ObtainWrite(&buf_globalLock);
/* destroy the buffer, turning off its dirty bit, if
* we're truncating the whole buffer. Otherwise, set
memset(bufp->datap + bufferPos, 0,
cm_data.buf_blockSize - bufferPos);
}
-
- lock_ReleaseWrite(&buf_globalLock);
}
lock_ReleaseMutex(&scp->mx);
lock_ReleaseMutex(&bufp->mx);
- if (!didRelease) {
- lock_ObtainWrite(&buf_globalLock);
- nbufp = bufp->fileHashp;
- if (nbufp) nbufp->refCount++;
- buf_LockedRelease(bufp);
- lock_ReleaseWrite(&buf_globalLock);
- }
-
- /* bail out early if we fail */
- if (code) {
- /* at this point, nbufp is held; bufp has already been
- * released.
- */
- if (nbufp)
- buf_Release(nbufp);
-
-#ifdef TESTING
- buf_ValidateBufQueues();
-#endif /* TESTING */
-
- return code;
- }
+
+ if (!code) {
+ nbufp = bufp->fileHashp;
+ if (nbufp)
+ buf_HoldLocked(nbufp);
+ } else {
+ /* This forces the loop to end and the error code
+ * to be returned. */
+ nbufp = NULL;
+ }
+ buf_ReleaseLocked(bufp);
+ lock_ReleaseWrite(&buf_globalLock);
}
#ifdef TESTING
buf_ValidateBufQueues();
#endif /* TESTING */
- /* success */
- return 0;
+ /* done */
+ return code;
}
long buf_FlushCleanPages(cm_scache_t *scp, cm_user_t *userp, cm_req_t *reqp)
lock_ObtainWrite(&buf_globalLock);
bp = cm_data.buf_fileHashTablepp[i];
if (bp)
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
+
for (; bp; bp = nbp) {
didRelease = 0; /* haven't released this buffer yet */
lock_ObtainMutex(&bp->mx);
/* start cleaning the buffer, and wait for it to finish */
- buf_LockedCleanAsync(bp, reqp);
+ buf_CleanAsyncLocked(bp, reqp);
buf_WaitIO(scp, bp);
lock_ReleaseMutex(&bp->mx);
*/
if (!(bp->flags & CM_BUF_DIRTY)) {
if (bp->refCount == 1) { /* bp is held above */
- buf_LockedRelease(bp);
nbp = bp->fileHashp;
if (nbp)
- nbp->refCount++;
+ buf_HoldLocked(nbp);
+ buf_ReleaseLocked(bp);
didRelease = 1;
buf_Recycle(bp);
}
skip:
if (!didRelease) {
lock_ObtainWrite(&buf_globalLock);
- if (nbp = bp->fileHashp)
- nbp->refCount++;
- buf_LockedRelease(bp);
+ nbp = bp->fileHashp;
+ if (nbp)
+ buf_HoldLocked(nbp);
+ buf_ReleaseLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
}
} /* for loop over a bunch of buffers */
#ifdef TESTING
- buf_ValidateBufQueues();
+ buf_ValidateBufQueues();
#endif /* TESTING */
/* done */
lock_ObtainWrite(&buf_globalLock);
bp = cm_data.buf_fileHashTablepp[i];
if (bp)
- bp->refCount++;
+ buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
for (; bp; bp = nbp) {
/* clean buffer synchronously */
}
lock_ObtainWrite(&buf_globalLock);
- buf_LockedRelease(bp);
nbp = bp->fileHashp;
if (nbp)
- nbp->refCount++;
+ buf_HoldLocked(nbp);
+ buf_ReleaseLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
} /* for loop over a bunch of buffers */
projects / packages / o / openafs.git / commitdiff