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38 * @(#)buf.h 8.9 (Berkeley) 3/30/95
39 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
40 * $DragonFly: src/sys/sys/buf2.h,v 1.21 2008/01/28 07:19:06 nth Exp $
49 #include <sys/buf.h> /* crit_*() functions */
51 #ifndef _SYS_GLOBALDATA_H_
52 #include <sys/globaldata.h> /* curthread */
54 #ifndef _SYS_THREAD2_H_
55 #include <sys/thread2.h> /* crit_*() functions */
57 #ifndef _SYS_SPINLOCK2_H_
58 #include <sys/spinlock2.h> /* crit_*() functions */
61 #include <sys/mount.h>
64 #include <sys/vnode.h>
66 #ifndef _VM_VM_PAGE_H_
67 #include <vm/vm_page.h>
73 #define BUF_LOCKINIT(bp) \
74 lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
78 * Get a lock sleeping non-interruptably until it becomes available.
80 * XXX lk_wmesg can race, but should not result in any operational issues.
83 BUF_LOCK(struct buf *bp, int locktype)
85 bp->b_lock.lk_wmesg = buf_wmesg;
86 return (lockmgr(&(bp)->b_lock, locktype));
89 * Get a lock sleeping with specified interruptably and timeout.
91 * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
92 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
93 * will not be set in that case.
95 * XXX lk_wmesg can race, but should not result in any operational issues.
98 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
100 bp->b_lock.lk_wmesg = wmesg;
101 bp->b_lock.lk_timo = timo;
102 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
105 * Release a lock. Only the acquiring process may free the lock unless
106 * it has been handed off to biodone.
109 BUF_UNLOCK(struct buf *bp)
111 lockmgr(&(bp)->b_lock, LK_RELEASE);
115 * When initiating asynchronous I/O, change ownership of the lock to the
116 * kernel. Once done, the lock may legally released by biodone. The
117 * original owning process can no longer acquire it recursively, but must
118 * wait until the I/O is completed and the lock has been freed by biodone.
121 BUF_KERNPROC(struct buf *bp)
123 lockmgr_kernproc(&(bp)->b_lock);
126 * Find out the number of references to a lock.
128 * The non-blocking version should only be used for assertions in cases
129 * where the buffer is expected to be owned or otherwise data stable.
132 BUF_REFCNT(struct buf *bp)
134 return (lockcount(&(bp)->b_lock));
138 BUF_REFCNTNB(struct buf *bp)
140 return (lockcountnb(&(bp)->b_lock));
144 * Free a buffer lock.
146 #define BUF_LOCKFREE(bp) \
147 if (BUF_REFCNTNB(bp) > 0) \
148 panic("free locked buf")
151 bioq_init(struct bio_queue_head *bioq)
153 TAILQ_INIT(&bioq->queue);
154 bioq->off_unused = 0;
156 bioq->transition = NULL;
157 bioq->bio_unused = NULL;
161 bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio)
163 bioq->transition = NULL;
164 TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act);
168 bioq_remove(struct bio_queue_head *bioq, struct bio *bio)
171 * Adjust read insertion point when removing the bioq. The
172 * bio after the insert point is a write so move backwards
173 * one (NULL will indicate all the reads have cleared).
175 if (bio == bioq->transition)
176 bioq->transition = TAILQ_NEXT(bio, bio_act);
177 TAILQ_REMOVE(&bioq->queue, bio, bio_act);
180 static __inline struct bio *
181 bioq_first(struct bio_queue_head *bioq)
183 return (TAILQ_FIRST(&bioq->queue));
187 * Adjust buffer cache buffer's activity count. This
188 * works similarly to vm_page->act_count.
191 buf_act_advance(struct buf *bp)
193 if (bp->b_act_count > ACT_MAX - ACT_ADVANCE)
194 bp->b_act_count = ACT_MAX;
196 bp->b_act_count += ACT_ADVANCE;
200 buf_act_decline(struct buf *bp)
202 if (bp->b_act_count < ACT_DECLINE)
205 bp->b_act_count -= ACT_DECLINE;
209 * biodeps inlines - used by softupdates and HAMMER.
212 buf_dep_init(struct buf *bp)
215 LIST_INIT(&bp->b_dep);
219 * Precondition: the buffer has some dependencies.
222 buf_deallocate(struct buf *bp)
224 struct bio_ops *ops = bp->b_ops;
226 KKASSERT(! LIST_EMPTY(&bp->b_dep));
228 ops->io_deallocate(bp);
232 buf_countdeps(struct buf *bp, int n)
234 struct bio_ops *ops = bp->b_ops;
238 r = ops->io_countdeps(bp, n);
245 buf_start(struct buf *bp)
247 struct bio_ops *ops = bp->b_ops;
254 buf_complete(struct buf *bp)
256 struct bio_ops *ops = bp->b_ops;
259 ops->io_complete(bp);
263 buf_fsync(struct vnode *vp)
265 struct bio_ops *ops = vp->v_mount->mnt_bioops;
269 r = ops->io_fsync(vp);
276 buf_movedeps(struct buf *bp1, struct buf *bp2)
278 struct bio_ops *ops = bp1->b_ops;
281 ops->io_movedeps(bp1, bp2);
285 buf_checkread(struct buf *bp)
287 struct bio_ops *ops = bp->b_ops;
290 return(ops->io_checkread(bp));
295 buf_checkwrite(struct buf *bp)
297 struct bio_ops *ops = bp->b_ops;
300 return(ops->io_checkwrite(bp));
305 * Chained biodone. The bio callback was made and the callback function
306 * wishes to chain the biodone. If no BIO's are left we call bpdone()
307 * with elseit=TRUE (asynchronous completion).
310 biodone_chain(struct bio *bio)
313 biodone(bio->bio_prev);
315 bpdone(bio->bio_buf, 1);
320 #endif /* !_SYS_BUF2_H_ */