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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>
70 #define BUF_LOCKINIT(bp) \
71 lockinit(&(bp)->b_lock, buf_wmesg, 0, 0)
75 * Get a lock sleeping non-interruptably until it becomes available.
77 * XXX lk_wmesg can race, but should not result in any operational issues.
80 BUF_LOCK(struct buf *bp, int locktype)
82 bp->b_lock.lk_wmesg = buf_wmesg;
83 return (lockmgr(&(bp)->b_lock, locktype));
86 * Get a lock sleeping with specified interruptably and timeout.
88 * XXX lk_timo can race against other entities calling BUF_TIMELOCK,
89 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK
90 * will not be set in that case.
92 * XXX lk_wmesg can race, but should not result in any operational issues.
95 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo)
97 bp->b_lock.lk_wmesg = wmesg;
98 bp->b_lock.lk_timo = timo;
99 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK));
102 * Release a lock. Only the acquiring process may free the lock unless
103 * it has been handed off to biodone.
106 BUF_UNLOCK(struct buf *bp)
108 lockmgr(&(bp)->b_lock, LK_RELEASE);
112 * When initiating asynchronous I/O, change ownership of the lock to the
113 * kernel. Once done, the lock may legally released by biodone. The
114 * original owning process can no longer acquire it recursively, but must
115 * wait until the I/O is completed and the lock has been freed by biodone.
118 BUF_KERNPROC(struct buf *bp)
120 lockmgr_kernproc(&(bp)->b_lock);
123 * Find out the number of references to a lock.
125 * The non-blocking version should only be used for assertions in cases
126 * where the buffer is expected to be owned or otherwise data stable.
129 BUF_REFCNT(struct buf *bp)
131 return (lockcount(&(bp)->b_lock));
135 BUF_REFCNTNB(struct buf *bp)
137 return (lockcountnb(&(bp)->b_lock));
141 * Free a buffer lock.
143 #define BUF_LOCKFREE(bp) \
144 if (BUF_REFCNTNB(bp) > 0) \
145 panic("free locked buf")
148 bioq_init(struct bio_queue_head *head)
150 TAILQ_INIT(&head->queue);
151 head->last_offset = 0;
152 head->insert_point = NULL;
153 head->switch_point = NULL;
157 bioq_insert_tail(struct bio_queue_head *head, struct bio *bio)
159 if ((bio->bio_buf->b_flags & B_ORDERED) != 0) {
160 head->insert_point = bio;
161 head->switch_point = NULL;
163 TAILQ_INSERT_TAIL(&head->queue, bio, bio_act);
167 bioq_remove(struct bio_queue_head *head, struct bio *bio)
169 if (bio == head->switch_point)
170 head->switch_point = TAILQ_NEXT(bio, bio_act);
171 if (bio == head->insert_point) {
172 head->insert_point = TAILQ_PREV(bio, bio_queue, bio_act);
173 if (head->insert_point == NULL)
174 head->last_offset = 0;
175 } else if (bio == TAILQ_FIRST(&head->queue))
176 head->last_offset = bio->bio_offset;
177 TAILQ_REMOVE(&head->queue, bio, bio_act);
178 if (TAILQ_FIRST(&head->queue) == head->switch_point)
179 head->switch_point = NULL;
182 static __inline struct bio *
183 bioq_first(struct bio_queue_head *head)
185 return (TAILQ_FIRST(&head->queue));
189 * biodeps inlines - used by softupdates and HAMMER.
192 buf_dep_init(struct buf *bp)
195 LIST_INIT(&bp->b_dep);
199 * Precondition: the buffer has some dependencies.
202 buf_deallocate(struct buf *bp)
204 struct bio_ops *ops = bp->b_ops;
206 KKASSERT(! LIST_EMPTY(&bp->b_dep));
208 ops->io_deallocate(bp);
212 buf_countdeps(struct buf *bp, int n)
214 struct bio_ops *ops = bp->b_ops;
218 r = ops->io_countdeps(bp, n);
225 buf_start(struct buf *bp)
227 struct bio_ops *ops = bp->b_ops;
234 buf_complete(struct buf *bp)
236 struct bio_ops *ops = bp->b_ops;
239 ops->io_complete(bp);
243 buf_fsync(struct vnode *vp)
245 struct bio_ops *ops = vp->v_mount->mnt_bioops;
249 r = ops->io_fsync(vp);
256 buf_movedeps(struct buf *bp1, struct buf *bp2)
258 struct bio_ops *ops = bp1->b_ops;
261 ops->io_movedeps(bp1, bp2);
265 buf_checkread(struct buf *bp)
267 struct bio_ops *ops = bp->b_ops;
270 return(ops->io_checkread(bp));
275 buf_checkwrite(struct buf *bp)
277 struct bio_ops *ops = bp->b_ops;
280 return(ops->io_checkwrite(bp));
286 #endif /* !_SYS_BUF2_H_ */