/*
* Release a buffer on to the free lists.
* Described in Bach (p. 46).
*/
void
brelse(struct buf *bp)
{
struct bqueues *bufq;
int s;
/* Block disk interrupts. */
s = splbio();
/*
* Determine which queue the buffer should be on, then put it there.
*/
/* If it's locked, don't report an error; try again later. */
if (ISSET(bp->b_flags, (B_LOCKED|B_ERROR)) == (B_LOCKED|B_ERROR))
CLR(bp->b_flags, B_ERROR);
/* If it's not cacheable, or an error, mark it invalid. */
if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR)))
SET(bp->b_flags, B_INVAL);
if ((bp->b_bufsize <= 0) || ISSET(bp->b_flags, B_INVAL)) {
/*
* If it's invalid or empty, dissociate it from its vnode
* and put on the head of the appropriate queue.
*/
if (LIST_FIRST(&bp->b_dep) != NULL)
buf_deallocate(bp);
if (ISSET(bp->b_flags, B_DELWRI)) {
CLR(bp->b_flags, B_DELWRI);
}
if (bp->b_vp) {
reassignbuf(bp);
brelvp(bp);
}
if (bp->b_bufsize <= 0) {
/* no data */
bufq = &bufqueues[BQ_EMPTY];
numemptybufs++;
} else {
/* invalid data */
bufq = &bufqueues[BQ_CLEAN];
numfreepages += btoc(bp->b_bufsize);
numcleanpages += btoc(bp->b_bufsize);
}
binsheadfree(bp, bufq);
} else {
/*
* It has valid data. Put it on the end of the appropriate
* queue, so that it'll stick around for as long as possible.
*/
if (ISSET(bp->b_flags, B_LOCKED))
/* locked in core */
bufq = &bufqueues[BQ_LOCKED];
else {
numfreepages += btoc(bp->b_bufsize);
if (!ISSET(bp->b_flags, B_DELWRI)) {
numcleanpages += btoc(bp->b_bufsize);
bufq = &bufqueues[BQ_CLEAN];
} else {
numdirtypages += btoc(bp->b_bufsize);
bufq = &bufqueues[BQ_DIRTY];
}
}
if (ISSET(bp->b_flags, B_AGE))
binsheadfree(bp, bufq);
else
binstailfree(bp, bufq);
}
/* Unlock the buffer. */
CLR(bp->b_flags, (B_AGE | B_ASYNC | B_BUSY | B_NOCACHE | B_DEFERRED));
/* Wake up syncer and cleaner processes waiting for buffers */
if (nobuffers) {
wakeup(&nobuffers);
nobuffers = 0;
}
/* Wake up any processes waiting for any buffer to become free. */
if (needbuffer && (numcleanpages > locleanpages)) {
needbuffer--;
wakeup_one(&needbuffer);
}
splx(s);
/* Wake up any processes waiting for _this_ buffer to become free. */
if (ISSET(bp->b_flags, B_WANTED)) {
CLR(bp->b_flags, B_WANTED);
wakeup(bp);
}
}
/*
* Release a buffer on to the free lists.
* Described in Bach (p. 46).
*/
void
brelse(struct buf *bp)
{
int s;
s = splbio();
if (bp->b_data != NULL)
KASSERT(bp->b_bufsize > 0);
/*
* Determine which queue the buffer should be on, then put it there.
*/
/* If it's not cacheable, or an error, mark it invalid. */
if (ISSET(bp->b_flags, (B_NOCACHE|B_ERROR)))
SET(bp->b_flags, B_INVAL);
if (ISSET(bp->b_flags, B_INVAL)) {
/*
* If the buffer is invalid, free it now rather than leaving
* it in a queue and wasting memory.
*/
if (LIST_FIRST(&bp->b_dep) != NULL)
buf_deallocate(bp);
if (ISSET(bp->b_flags, B_DELWRI)) {
CLR(bp->b_flags, B_DELWRI);
}
if (bp->b_vp) {
RB_REMOVE(buf_rb_bufs, &bp->b_vp->v_bufs_tree,
bp);
brelvp(bp);
}
bp->b_vp = NULL;
/*
* Wake up any processes waiting for _this_ buffer to
* become free. They are not allowed to grab it
* since it will be freed. But the only sleeper is
* getblk and it will restart the operation after
* sleep.
*/
if (ISSET(bp->b_flags, B_WANTED)) {
CLR(bp->b_flags, B_WANTED);
wakeup(bp);
}
buf_put(bp);
} else {
/*
* It has valid data. Put it on the end of the appropriate
* queue, so that it'll stick around for as long as possible.
*/
bufcache_release(bp);
/* Unlock the buffer. */
CLR(bp->b_flags, (B_AGE | B_ASYNC | B_NOCACHE | B_DEFERRED));
buf_release(bp);
/* Wake up any processes waiting for _this_ buffer to
* become free. */
if (ISSET(bp->b_flags, B_WANTED)) {
CLR(bp->b_flags, B_WANTED);
wakeup(bp);
}
}
/* Wake up syncer and cleaner processes waiting for buffers. */
if (nobuffers) {
nobuffers = 0;
wakeup(&nobuffers);
}
/* Wake up any processes waiting for any buffer to become free. */
if (needbuffer && bcstats.numbufpages < targetpages &&
bcstats.kvaslots_avail > RESERVE_SLOTS) {
needbuffer = 0;
wakeup(&needbuffer);
}
splx(s);
}