Function bqrelse

freebsd/kern/vfs_bio.c:2818–2875

* Release a buffer back to the appropriate queue but do not try to free * it. The buffer is expected to be used again soon. * * bqrelse() is used by bdwrite() to requeue a delayed write, and used by * biodone() to requeue an async I/O on completion. It is also used when * known good buffers need to be requeued but we think we may need the data * again soon. * * XXX we should be able to l

 * XXX we should be able to leave the B_RELBUF hint set on completion.
 */
void
bqrelse(struct buf *bp)
{
	int qindex;

	CTR3(KTR_BUF, "bqrelse(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
	KASSERT(!(bp->b_flags & (B_CLUSTER|B_PAGING)),
	    ("bqrelse: inappropriate B_PAGING or B_CLUSTER bp %p", bp));

	qindex = QUEUE_NONE;
	if (BUF_LOCKRECURSED(bp)) {
		/* do not release to free list */
		BUF_UNLOCK(bp);
		return;
	}
	bp->b_flags &= ~(B_ASYNC | B_NOCACHE | B_AGE | B_RELBUF);
	bp->b_xflags &= ~(BX_CVTENXIO);

	if (LIST_EMPTY(&bp->b_dep)) {
		bp->b_flags &= ~B_IOSTARTED;
	} else {
		KASSERT((bp->b_flags & B_IOSTARTED) == 0,
		    ("bqrelse: SU io not finished bp %p", bp));
	}

	if (bp->b_flags & B_MANAGED) {
		if (bp->b_flags & B_REMFREE)
			bremfreef(bp);
		goto out;
	}

	/* buffers with stale but valid contents */
	if ((bp->b_flags & B_DELWRI) != 0 || (bp->b_vflags & (BV_BKGRDINPROG |
	    BV_BKGRDERR)) == BV_BKGRDERR) {
		BO_LOCK(bp->b_bufobj);
		bp->b_vflags &= ~BV_BKGRDERR;
		BO_UNLOCK(bp->b_bufobj);
		qindex = QUEUE_DIRTY;
	} else {
		if ((bp->b_flags & B_DELWRI) == 0 &&
		    (bp->b_xflags & BX_VNDIRTY))
			panic("bqrelse: not dirty");
		if ((bp->b_flags & B_NOREUSE) != 0) {
			brelse(bp);
			return;
		}
		qindex = QUEUE_CLEAN;
	}
	buf_track(bp, __func__);
	/* binsfree unlocks bp. */
	binsfree(bp, qindex);
	return;

out:
	buf_track(bp, __func__);
	/* unlock */
	BUF_UNLOCK(bp);
}