void buf_HoldLocked(cm_buf_t *bp)
{
osi_assertx(bp->magic == CM_BUF_MAGIC,"incorrect cm_buf_t magic");
- bp->refCount++;
+ InterlockedIncrement(&bp->refCount);
}
/* hold a reference to an already held buffer */
void buf_Hold(cm_buf_t *bp)
{
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
buf_HoldLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
}
/* code to drop reference count while holding buf_globalLock */
-void buf_ReleaseLocked(cm_buf_t *bp)
+void buf_ReleaseLocked(cm_buf_t *bp, afs_uint32 writeLocked)
{
+ afs_int32 refCount;
+
+ if (writeLocked)
+ lock_AssertWrite(&buf_globalLock);
+ else
+ lock_AssertRead(&buf_globalLock);
+
/* ensure that we're in the LRU queue if our ref count is 0 */
osi_assertx(bp->magic == CM_BUF_MAGIC,"incorrect cm_buf_t magic");
+
+ refCount = InterlockedDecrement(&bp->refCount);
#ifdef DEBUG
- if (bp->refCount == 0)
+ if (refCount < 0)
osi_panic("buf refcount 0",__FILE__,__LINE__);;
#else
- osi_assertx(bp->refCount > 0, "cm_buf_t refCount == 0");
+ osi_assertx(refCount >= 0, "cm_buf_t refCount == 0");
#endif
- if (--bp->refCount == 0) {
- if (!(bp->flags & CM_BUF_INLRU)) {
+ if (refCount == 0) {
+ /*
+ * If we are read locked there could be a race condition
+ * with buf_Find() so we must obtain a write lock and
+ * double check that the refCount is actually zero
+ * before we remove the buffer from the LRU queue.
+ */
+ if (!writeLocked) {
+ lock_ReleaseRead(&buf_globalLock);
+ lock_ObtainWrite(&buf_globalLock);
+ }
+
+ if (bp->refCount == 0 &&
+ !(bp->flags & CM_BUF_INLRU)) {
osi_QAdd((osi_queue_t **) &cm_data.buf_freeListp, &bp->q);
/* watch for transition from empty to one element */
cm_data.buf_freeListEndp = cm_data.buf_freeListp;
bp->flags |= CM_BUF_INLRU;
}
+
+ if (!writeLocked) {
+ lock_ReleaseWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
+ }
}
}
/* release a buffer. Buffer must be referenced, but unlocked. */
void buf_Release(cm_buf_t *bp)
{
- lock_ObtainWrite(&buf_globalLock);
- buf_ReleaseLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ afs_int32 refCount;
+
+ /* ensure that we're in the LRU queue if our ref count is 0 */
+ osi_assertx(bp->magic == CM_BUF_MAGIC,"incorrect cm_buf_t magic");
+
+ refCount = InterlockedDecrement(&bp->refCount);
+#ifdef DEBUG
+ if (refCount < 0)
+ osi_panic("buf refcount 0",__FILE__,__LINE__);;
+#else
+ osi_assertx(refCount >= 0, "cm_buf_t refCount == 0");
+#endif
+ if (refCount == 0) {
+ lock_ObtainWrite(&buf_globalLock);
+ if (bp->refCount == 0 &&
+ !(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;
+ }
+ lock_ReleaseWrite(&buf_globalLock);
+ }
}
/* incremental sync daemon. Writes all dirty buffers every 5000 ms */
bp->dirtyp = NULL;
if (cm_data.buf_dirtyListp == NULL)
cm_data.buf_dirtyListEndp = NULL;
- buf_ReleaseLocked(bp);
+ buf_ReleaseLocked(bp, TRUE);
lock_ReleaseWrite(&buf_globalLock);
} else {
/* advance the pointer so we don't loop forever */
{
cm_buf_t *bp;
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
bp = buf_FindLocked(scp, offsetp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
return bp;
}
*/
void buf_Recycle(cm_buf_t *bp)
{
- int i;
+ afs_uint32 i;
cm_buf_t **lbpp;
cm_buf_t *tbp;
cm_buf_t *prevBp, *nextBp;
*/
bp->refCount--;
lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&scp->bufCreateLock);
return CM_BUF_EXISTS;
}
}
*/
buf_HoldLocked(bp);
lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&scp->bufCreateLock);
/* grab required lock and clean; this only
* starts the I/O. By the time we're back,
osi_assertx(bp->magic == CM_BUF_MAGIC, "invalid cm_buf_t magic");
osi_assertx(bp->refCount > 0, "cm_buf_t refcount 0");
- lock_ObtainWrite(&buf_globalLock);
if (bp->flags & CM_BUF_DIRTY) {
osi_Log1(buf_logp, "buf_SetDirty 0x%p already dirty", bp);
* elsewhere, never add to the dirty list if the buffer is
* already there.
*/
+ lock_ObtainWrite(&buf_globalLock);
if (bp->dirtyp == NULL && cm_data.buf_dirtyListEndp != bp) {
buf_HoldLocked(bp);
if (!cm_data.buf_dirtyListp) {
}
bp->dirtyp = NULL;
}
+ lock_ReleaseWrite(&buf_globalLock);
}
- lock_ReleaseWrite(&buf_globalLock);
}
/* clean all buffers, reset log pointers and invalidate all buffers.
cm_buf_t *bp;
cm_req_t req;
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
for(i=0; i<cm_data.buf_hashSize; i++) {
for(bp = cm_data.buf_scacheHashTablepp[i]; bp; bp = bp->hashp) {
if ((bp->flags & CM_BUF_DIRTY) == CM_BUF_DIRTY) {
buf_HoldLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
/* now no locks are held; clean buffer and go on */
cm_InitReq(&req);
buf_CleanWait(NULL, bp);
/* relock and release buffer */
- lock_ObtainWrite(&buf_globalLock);
- buf_ReleaseLocked(bp);
+ lock_ObtainRead(&buf_globalLock);
+ buf_ReleaseLocked(bp, FALSE);
} /* dirty */
} /* over one bucket */
} /* for loop over all hash buckets */
/* release locks */
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
#ifdef TESTING
buf_ValidateBufQueues();
osi_hyper_t bufEnd;
long code;
long bufferPos;
- long i;
+ afs_uint32 i;
/* assert that cm_bufCreateLock is held in write mode */
lock_AssertWrite(&scp->bufCreateLock);
i = BUF_FILEHASH(&scp->fid);
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
bufp = cm_data.buf_fileHashTablepp[i];
if (bufp == NULL) {
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
return 0;
}
buf_HoldLocked(bufp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
while (bufp) {
lock_ObtainMutex(&bufp->mx);
| CM_SCACHESYNC_BUFLOCKED);
- 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) {
nbufp = bufp->fileHashp;
if (nbufp)
- buf_HoldLocked(nbufp);
+ buf_Hold(nbufp);
} else {
/* This forces the loop to end and the error code
* to be returned. */
nbufp = NULL;
}
- buf_ReleaseLocked(bufp);
- lock_ReleaseWrite(&buf_globalLock);
+ buf_Release(bufp);
bufp = nbufp;
}
cm_buf_t *bp; /* buffer we're hacking on */
cm_buf_t *nbp;
int didRelease;
- long i;
+ afs_uint32 i;
i = BUF_FILEHASH(&scp->fid);
code = 0;
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
bp = cm_data.buf_fileHashTablepp[i];
if (bp)
buf_HoldLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
for (; bp; bp = nbp) {
didRelease = 0; /* haven't released this buffer yet */
bp->dirtyCounter++;
lock_ReleaseMutex(&bp->mx);
- lock_ObtainWrite(&buf_globalLock);
/* actually, we only know that buffer is clean if ref
* count is 1, since we don't have buffer itself locked.
*/
if (!(bp->flags & CM_BUF_DIRTY)) {
+ lock_ObtainWrite(&buf_globalLock);
if (bp->refCount == 1) { /* bp is held above */
nbp = bp->fileHashp;
if (nbp)
buf_HoldLocked(nbp);
- buf_ReleaseLocked(bp);
+ buf_ReleaseLocked(bp, TRUE);
didRelease = 1;
buf_Recycle(bp);
}
+ lock_ReleaseWrite(&buf_globalLock);
}
- lock_ReleaseWrite(&buf_globalLock);
if (code != CM_ERROR_BADFD)
(*cm_buf_opsp->Unstabilizep)(scp, userp);
skip:
if (!didRelease) {
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
nbp = bp->fileHashp;
if (nbp)
buf_HoldLocked(nbp);
- buf_ReleaseLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ buf_ReleaseLocked(bp, FALSE);
+ lock_ReleaseRead(&buf_globalLock);
}
} /* for loop over a bunch of buffers */
i = BUF_FILEHASH(&scp->fid);
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
bp = cm_data.buf_fileHashTablepp[i];
if (bp)
buf_HoldLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ lock_ReleaseRead(&buf_globalLock);
for (; bp; bp = nbp) {
/* clean buffer synchronously */
if (cm_FidCmp(&bp->fid, &scp->fid) == 0) {
lock_ReleaseMutex(&bp->mx);
}
- lock_ObtainWrite(&buf_globalLock);
+ lock_ObtainRead(&buf_globalLock);
nbp = bp->fileHashp;
if (nbp)
buf_HoldLocked(nbp);
- buf_ReleaseLocked(bp);
- lock_ReleaseWrite(&buf_globalLock);
+ buf_ReleaseLocked(bp, FALSE);
+ lock_ReleaseRead(&buf_globalLock);
} /* for loop over a bunch of buffers */
#ifdef TESTING
git://git.openafs.org / openafs.git / blobdiff