2 * Copyright (c) 2007 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/vfs/hammer/hammer_inode.c,v 1.21 2008/01/17 05:06:09 dillon Exp $
42 * The kernel is not actively referencing this vnode but is still holding
46 hammer_vop_inactive(struct vop_inactive_args *ap)
48 struct hammer_inode *ip = VTOI(ap->a_vp);
59 * If the inode no longer has any references we recover its
60 * in-memory resources immediately.
62 if (ip->ino_rec.ino_nlinks == 0)
68 * Release the vnode association. This is typically (but not always)
69 * the last reference on the inode and will flush the inode to the
72 * XXX Currently our sync code only runs through inodes with vnode
73 * associations, so we depend on hammer_rel_inode() to sync any inode
74 * record data to the block device prior to losing the association.
75 * Otherwise transactions that the user expected to be distinct by
76 * doing a manual sync may be merged.
79 hammer_vop_reclaim(struct vop_reclaim_args *ap)
81 struct hammer_inode *ip;
86 if ((ip = vp->v_data) != NULL) {
89 hammer_rel_inode(ip, 0);
95 * Obtain a vnode for the specified inode number. An exclusively locked
99 hammer_vfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
101 struct hammer_mount *hmp = (void *)mp->mnt_data;
102 struct hammer_inode *ip;
106 * Get/allocate the hammer_inode structure. The structure must be
107 * unlocked while we manipulate the related vnode to avoid a
110 ip = hammer_get_inode(hmp, NULL, ino, hmp->asof, 0, &error);
115 error = hammer_get_vnode(ip, LK_EXCLUSIVE, vpp);
116 hammer_rel_inode(ip, 0);
121 * Return a locked vnode for the specified inode. The inode must be
122 * referenced but NOT LOCKED on entry and will remain referenced on
126 hammer_get_vnode(struct hammer_inode *ip, int lktype, struct vnode **vpp)
132 if ((vp = ip->vp) == NULL) {
133 error = getnewvnode(VT_HAMMER, ip->hmp->mp, vpp, 0, 0);
136 hammer_lock_ex(&ip->lock);
137 if (ip->vp != NULL) {
138 hammer_unlock(&ip->lock);
143 hammer_ref(&ip->lock);
146 vp->v_type = hammer_get_vnode_type(
147 ip->ino_rec.base.base.obj_type);
149 switch(ip->ino_rec.base.base.obj_type) {
150 case HAMMER_OBJTYPE_CDEV:
151 case HAMMER_OBJTYPE_BDEV:
152 vp->v_ops = &ip->hmp->mp->mnt_vn_spec_ops;
153 addaliasu(vp, ip->ino_data.rmajor,
154 ip->ino_data.rminor);
156 case HAMMER_OBJTYPE_FIFO:
157 vp->v_ops = &ip->hmp->mp->mnt_vn_fifo_ops;
162 if (ip->obj_id == HAMMER_OBJID_ROOT)
165 vp->v_data = (void *)ip;
166 /* vnode locked by getnewvnode() */
167 /* make related vnode dirty if inode dirty? */
168 hammer_unlock(&ip->lock);
169 if (vp->v_type == VREG)
170 vinitvmio(vp, ip->ino_rec.ino_size);
175 * loop if the vget fails (aka races), or if the vp
176 * no longer matches ip->vp.
178 if (vget(vp, LK_EXCLUSIVE) == 0) {
189 * Acquire a HAMMER inode. The returned inode is not locked. These functions
190 * do not attach or detach the related vnode (use hammer_get_vnode() for
193 * The flags argument is only applied for newly created inodes, and only
194 * certain flags are inherited.
196 struct hammer_inode *
197 hammer_get_inode(struct hammer_mount *hmp, struct hammer_node **cache,
198 u_int64_t obj_id, hammer_tid_t asof, int flags, int *errorp)
200 struct hammer_inode_info iinfo;
201 struct hammer_cursor cursor;
202 struct hammer_inode *ip;
205 * Determine if we already have an inode cached. If we do then
208 iinfo.obj_id = obj_id;
209 iinfo.obj_asof = asof;
211 ip = hammer_ino_rb_tree_RB_LOOKUP_INFO(&hmp->rb_inos_root, &iinfo);
213 hammer_ref(&ip->lock);
218 ip = kmalloc(sizeof(*ip), M_HAMMER, M_WAITOK|M_ZERO);
219 ++hammer_count_inodes;
221 ip->obj_asof = iinfo.obj_asof;
223 ip->flags = flags & HAMMER_INODE_RO;
225 ip->flags |= HAMMER_INODE_RO;
226 RB_INIT(&ip->rec_tree);
229 * Locate the on-disk inode.
231 hammer_init_cursor_hmp(&cursor, cache, hmp);
232 cursor.key_beg.obj_id = ip->obj_id;
233 cursor.key_beg.key = 0;
234 cursor.key_beg.create_tid = 0;
235 cursor.key_beg.delete_tid = 0;
236 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
237 cursor.key_beg.obj_type = 0;
238 cursor.asof = iinfo.obj_asof;
239 cursor.flags = HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_GET_DATA |
242 *errorp = hammer_btree_lookup(&cursor);
245 * On success the B-Tree lookup will hold the appropriate
246 * buffer cache buffers and provide a pointer to the requested
247 * information. Copy the information to the in-memory inode
248 * and cache the B-Tree node to improve future operations.
251 ip->ino_rec = cursor.record->inode;
252 ip->ino_data = cursor.data->inode;
253 hammer_cache_node(cursor.node, &ip->cache[0]);
255 hammer_cache_node(cursor.node, cache);
259 * On success load the inode's record and data and insert the
260 * inode into the B-Tree. It is possible to race another lookup
261 * insertion of the same inode so deal with that condition too.
263 * The cursor's locked node interlocks against others creating and
264 * destroying ip while we were blocked.
267 hammer_ref(&ip->lock);
268 if (RB_INSERT(hammer_ino_rb_tree, &hmp->rb_inos_root, ip)) {
269 hammer_uncache_node(&ip->cache[0]);
270 hammer_uncache_node(&ip->cache[1]);
271 hammer_unref(&ip->lock);
272 --hammer_count_inodes;
274 hammer_done_cursor(&cursor);
277 ip->flags |= HAMMER_INODE_ONDISK;
279 --hammer_count_inodes;
283 hammer_done_cursor(&cursor);
288 * Create a new filesystem object, returning the inode in *ipp. The
289 * returned inode will be referenced but not locked.
291 * The inode is created in-memory and will be delay-synchronized to the
295 hammer_create_inode(hammer_transaction_t trans, struct vattr *vap,
296 struct ucred *cred, hammer_inode_t dip,
297 struct hammer_inode **ipp)
304 ip = kmalloc(sizeof(*ip), M_HAMMER, M_WAITOK|M_ZERO);
305 ++hammer_count_inodes;
306 ip->obj_id = hammer_alloc_tid(trans);
307 KKASSERT(ip->obj_id != 0);
308 ip->obj_asof = hmp->asof;
310 ip->flags = HAMMER_INODE_DDIRTY | HAMMER_INODE_RDIRTY |
312 ip->last_tid = trans->tid;
314 RB_INIT(&ip->rec_tree);
316 ip->ino_rec.ino_atime = trans->tid;
317 ip->ino_rec.ino_mtime = trans->tid;
318 ip->ino_rec.ino_size = 0;
319 ip->ino_rec.ino_nlinks = 0;
321 ip->ino_rec.base.rec_id = hammer_alloc_recid(trans);
322 KKASSERT(ip->ino_rec.base.rec_id != 0);
323 ip->ino_rec.base.base.btype = HAMMER_BTREE_TYPE_RECORD;
324 ip->ino_rec.base.base.obj_id = ip->obj_id;
325 ip->ino_rec.base.base.key = 0;
326 ip->ino_rec.base.base.create_tid = trans->tid;
327 ip->ino_rec.base.base.delete_tid = 0;
328 ip->ino_rec.base.base.rec_type = HAMMER_RECTYPE_INODE;
329 ip->ino_rec.base.base.obj_type = hammer_get_obj_type(vap->va_type);
331 ip->ino_data.version = HAMMER_INODE_DATA_VERSION;
332 ip->ino_data.mode = vap->va_mode;
333 ip->ino_data.ctime = trans->tid;
334 ip->ino_data.parent_obj_id = (dip) ? dip->ino_rec.base.base.obj_id : 0;
336 switch(ip->ino_rec.base.base.obj_type) {
337 case HAMMER_OBJTYPE_CDEV:
338 case HAMMER_OBJTYPE_BDEV:
339 ip->ino_data.rmajor = vap->va_rmajor;
340 ip->ino_data.rminor = vap->va_rminor;
347 * Calculate default uid/gid and overwrite with information from
350 xuid = hammer_to_unix_xid(&dip->ino_data.uid);
351 ip->ino_data.gid = dip->ino_data.gid;
352 xuid = vop_helper_create_uid(hmp->mp, dip->ino_data.mode, xuid, cred,
354 ip->ino_data.mode = vap->va_mode;
356 if (vap->va_vaflags & VA_UID_UUID_VALID)
357 ip->ino_data.uid = vap->va_uid_uuid;
358 else if (vap->va_uid != (uid_t)VNOVAL)
359 hammer_guid_to_uuid(&ip->ino_data.uid, xuid);
360 if (vap->va_vaflags & VA_GID_UUID_VALID)
361 ip->ino_data.gid = vap->va_gid_uuid;
362 else if (vap->va_gid != (gid_t)VNOVAL)
363 hammer_guid_to_uuid(&ip->ino_data.gid, vap->va_gid);
365 hammer_ref(&ip->lock);
366 if (RB_INSERT(hammer_ino_rb_tree, &hmp->rb_inos_root, ip)) {
367 hammer_unref(&ip->lock);
368 panic("hammer_create_inode: duplicate obj_id %llx", ip->obj_id);
375 * Called by hammer_sync_inode().
378 hammer_update_inode(hammer_inode_t ip)
380 struct hammer_cursor cursor;
381 struct hammer_cursor *spike = NULL;
382 hammer_record_t record;
384 hammer_tid_t last_tid;
387 * Locate the record on-disk and mark it as deleted. Both the B-Tree
388 * node and the record must be marked deleted. The record may or
389 * may not be physically deleted, depending on the retention policy.
391 * If the inode has already been deleted on-disk we have nothing
394 * XXX Update the inode record and data in-place if the retention
397 last_tid = ip->last_tid;
401 if ((ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DELONDISK)) ==
402 HAMMER_INODE_ONDISK) {
403 hammer_init_cursor_hmp(&cursor, &ip->cache[0], ip->hmp);
404 cursor.key_beg.obj_id = ip->obj_id;
405 cursor.key_beg.key = 0;
406 cursor.key_beg.create_tid = 0;
407 cursor.key_beg.delete_tid = 0;
408 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
409 cursor.key_beg.obj_type = 0;
410 cursor.asof = ip->obj_asof;
411 cursor.flags |= HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_ASOF;
413 error = hammer_btree_lookup(&cursor);
416 error = hammer_ip_delete_record(&cursor, last_tid);
418 ip->flags |= HAMMER_INODE_DELONDISK;
420 hammer_cache_node(cursor.node, &ip->cache[0]);
421 hammer_done_cursor(&cursor);
425 * Write out a new record if the in-memory inode is not marked
426 * as having been deleted. Update our inode statistics if this
427 * is the first application of the inode on-disk.
429 * If the inode has been deleted permanently, HAMMER_INODE_DELONDISK
430 * will remain set and prevent further updates.
432 if (error == 0 && (ip->flags & HAMMER_INODE_DELETED) == 0) {
433 record = hammer_alloc_mem_record(ip);
434 record->rec.inode = ip->ino_rec;
435 record->rec.inode.base.base.create_tid = last_tid;
436 record->rec.inode.base.data_len = sizeof(ip->ino_data);
437 record->data = (void *)&ip->ino_data;
438 error = hammer_ip_sync_record(record, &spike);
439 record->flags |= HAMMER_RECF_DELETED;
440 hammer_rel_mem_record(record);
441 if (error == ENOSPC) {
442 error = hammer_spike(&spike);
446 KKASSERT(spike == NULL);
448 ip->flags &= ~(HAMMER_INODE_RDIRTY |
449 HAMMER_INODE_DDIRTY |
450 HAMMER_INODE_DELONDISK |
451 HAMMER_INODE_ITIMES);
452 if ((ip->flags & HAMMER_INODE_ONDISK) == 0) {
453 hammer_modify_volume(ip->hmp->rootvol);
454 ++ip->hmp->rootvol->ondisk->vol0_stat_inodes;
455 ip->flags |= HAMMER_INODE_ONDISK;
463 * Update only the itimes fields. This is done no-historically. The
464 * record is updated in-place on the disk.
467 hammer_update_itimes(hammer_inode_t ip)
469 struct hammer_cursor cursor;
470 struct hammer_inode_record *rec;
474 if ((ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DELONDISK)) ==
475 HAMMER_INODE_ONDISK) {
476 hammer_init_cursor_hmp(&cursor, &ip->cache[0], ip->hmp);
477 cursor.key_beg.obj_id = ip->obj_id;
478 cursor.key_beg.key = 0;
479 cursor.key_beg.create_tid = 0;
480 cursor.key_beg.delete_tid = 0;
481 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
482 cursor.key_beg.obj_type = 0;
483 cursor.asof = ip->obj_asof;
484 cursor.flags |= HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_ASOF;
486 error = hammer_btree_lookup(&cursor);
489 rec = &cursor.record->inode;
490 hammer_modify_buffer(cursor.record_buffer);
491 rec->ino_atime = ip->ino_rec.ino_atime;
492 rec->ino_mtime = ip->ino_rec.ino_mtime;
493 ip->flags &= ~HAMMER_INODE_ITIMES;
494 /* XXX recalculate crc */
496 hammer_cache_node(cursor.node, &ip->cache[0]);
497 hammer_done_cursor(&cursor);
503 * Release a reference on an inode. If asked to flush the last release
504 * will flush the inode.
507 hammer_rel_inode(struct hammer_inode *ip, int flush)
509 hammer_unref(&ip->lock);
511 ip->flags |= HAMMER_INODE_FLUSH;
512 if (ip->lock.refs == 0) {
513 if (ip->flags & HAMMER_INODE_FLUSH)
514 hammer_unload_inode(ip, (void *)MNT_WAIT);
516 hammer_unload_inode(ip, (void *)MNT_NOWAIT);
521 * Unload and destroy the specified inode.
523 * (called via RB_SCAN)
526 hammer_unload_inode(struct hammer_inode *ip, void *data)
530 KASSERT(ip->lock.refs == 0,
531 ("hammer_unload_inode: %d refs\n", ip->lock.refs));
532 KKASSERT(ip->vp == NULL);
533 hammer_ref(&ip->lock);
535 error = hammer_sync_inode(ip, (int)data, 1);
537 kprintf("hammer_sync_inode failed error %d\n", error);
538 if (ip->lock.refs == 1) {
539 KKASSERT(RB_EMPTY(&ip->rec_tree));
540 RB_REMOVE(hammer_ino_rb_tree, &ip->hmp->rb_inos_root, ip);
542 hammer_uncache_node(&ip->cache[0]);
543 hammer_uncache_node(&ip->cache[1]);
544 --hammer_count_inodes;
547 hammer_unref(&ip->lock);
553 * A transaction has modified an inode, requiring updates as specified by
556 * HAMMER_INODE_RDIRTY: Inode record has been updated
557 * HAMMER_INODE_DDIRTY: Inode data has been updated
558 * HAMMER_INODE_DELETED: Inode record/data must be deleted
559 * HAMMER_INODE_ITIMES: mtime/atime has been updated
561 * last_tid is the TID to use to generate the correct TID when the inode
565 hammer_modify_inode(struct hammer_transaction *trans,
566 struct hammer_inode *ip, int flags)
568 KKASSERT ((ip->flags & HAMMER_INODE_RO) == 0 ||
569 (HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|
570 HAMMER_INODE_DELETED|HAMMER_INODE_ITIMES) == 0);
573 (HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|HAMMER_INODE_DELETED)) {
574 if (hammer_debug_tid) {
575 kprintf("hammer_modify_inode: %016llx (%08x)\n",
576 trans->tid, (int)(trans->tid / 1000000000LL));
578 ip->last_tid = trans->tid;
584 * Sync any dirty buffers and records associated with an inode. The
585 * inode's last_tid field is used as the transaction id for the sync,
586 * overriding any intermediate TIDs that were used for records. Note
587 * that the dirty buffer cache buffers do not have any knowledge of
588 * the transaction id they were modified under.
590 * If we can't sync due to a cluster becoming full the spike structure
591 * will be filled in and ENOSPC returned. We must return -ENOSPC to
592 * terminate the RB_SCAN.
595 hammer_sync_inode_callback(hammer_record_t rec, void *data)
597 struct hammer_cursor **spike = data;
600 hammer_ref(&rec->lock);
601 error = hammer_ip_sync_record(rec, spike);
602 hammer_rel_mem_record(rec);
606 if (error != -ENOSPC) {
607 kprintf("hammer_sync_inode_callback: sync failed rec "
608 "%p, error %d\n", rec, error);
618 hammer_sync_inode(hammer_inode_t ip, int waitfor, int handle_delete)
620 struct hammer_transaction trans;
621 struct hammer_cursor *spike = NULL;
624 if ((ip->flags & HAMMER_INODE_MODMASK) == 0) {
628 hammer_lock_ex(&ip->lock);
631 * Use the transaction id of the last operation to sync.
634 hammer_start_transaction_tid(&trans, ip->hmp, ip->last_tid);
636 hammer_start_transaction(&trans, ip->hmp);
639 * If the inode has been deleted (nlinks == 0), and the OS no longer
640 * has any references to it (handle_delete != 0), clean up in-memory
643 * NOTE: We do not set the RDIRTY flag when updating the delete_tid,
644 * setting HAMMER_INODE_DELETED takes care of it.
646 * NOTE: Because we may sync records within this new transaction,
647 * force the inode update later on to use our transaction id or
648 * the delete_tid of the inode may be less then the create_tid of
649 * the inode update. XXX shouldn't happen but don't take the chance.
651 * NOTE: The call to hammer_ip_delete_range() cannot return ENOSPC
652 * so we can pass a NULL spike structure, because no partial data
653 * deletion can occur (yet).
655 if (ip->ino_rec.ino_nlinks == 0 && handle_delete &&
656 (ip->flags & HAMMER_INODE_GONE) == 0) {
657 ip->flags |= HAMMER_INODE_GONE;
659 vtruncbuf(ip->vp, 0, HAMMER_BUFSIZE);
660 error = hammer_ip_delete_range_all(&trans, ip);
661 KKASSERT(RB_EMPTY(&ip->rec_tree));
662 ip->ino_rec.base.base.delete_tid = trans.tid;
663 hammer_modify_inode(&trans, ip, HAMMER_INODE_DELETED);
664 hammer_modify_volume(ip->hmp->rootvol);
665 --ip->hmp->rootvol->ondisk->vol0_stat_inodes;
669 * Sync the buffer cache.
671 if (ip->vp != NULL) {
672 error = vfsync(ip->vp, waitfor, 1, NULL, NULL);
673 if (RB_ROOT(&ip->vp->v_rbdirty_tree) == NULL)
674 ip->flags &= ~HAMMER_INODE_BUFS;
681 * Now sync related records
684 error = RB_SCAN(hammer_rec_rb_tree, &ip->rec_tree, NULL,
685 hammer_sync_inode_callback, &spike);
686 KKASSERT(error <= 0);
689 if (error == ENOSPC) {
690 error = hammer_spike(&spike);
696 if (RB_EMPTY(&ip->rec_tree))
697 ip->flags &= ~HAMMER_INODE_XDIRTY;
700 * Now update the inode's on-disk inode-data and/or on-disk record.
702 switch(ip->flags & (HAMMER_INODE_DELETED|HAMMER_INODE_ONDISK)) {
703 case HAMMER_INODE_DELETED|HAMMER_INODE_ONDISK:
705 * If deleted and on-disk, don't set any additional flags.
706 * the delete flag takes care of things.
709 case HAMMER_INODE_DELETED:
711 * Take care of the case where a deleted inode was never
712 * flushed to the disk in the first place.
714 ip->flags &= ~(HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|
715 HAMMER_INODE_XDIRTY|HAMMER_INODE_ITIMES);
716 while (RB_ROOT(&ip->rec_tree)) {
717 hammer_record_t rec = RB_ROOT(&ip->rec_tree);
718 hammer_ref(&rec->lock);
719 rec->flags |= HAMMER_RECF_DELETED;
720 hammer_rel_mem_record(rec);
723 case HAMMER_INODE_ONDISK:
725 * If already on-disk, do not set any additional flags.
730 * If not on-disk and not deleted, set both dirty flags
731 * to force an initial record to be written.
733 ip->flags |= HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY;
738 * If RDIRTY or DDIRTY is set, write out a new record. If the inode
739 * is already on-disk the old record is marked as deleted.
741 * If DELETED is set hammer_update_inode() will delete the existing
742 * record without writing out a new one.
744 * If *ONLY* the ITIMES flag is set we can update the record in-place.
746 if ((ip->flags & (HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY |
747 HAMMER_INODE_ITIMES | HAMMER_INODE_DELETED)) ==
748 HAMMER_INODE_ITIMES) {
749 error = hammer_update_itimes(ip);
751 if (ip->flags & (HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY |
752 HAMMER_INODE_ITIMES | HAMMER_INODE_DELETED)) {
753 error = hammer_update_inode(ip);
755 hammer_commit_transaction(&trans);
756 hammer_unlock(&ip->lock);
761 * Access the filesystem buffer containing the cluster-relative byte
762 * offset, validate the buffer type, load *bufferp and return a
763 * pointer to the requested data. The buffer is reference and locked on
766 * If buf_type is 0 the buffer is assumed to be a pure-data buffer and
767 * no type or crc check is performed.
769 * If *bufferp is not NULL on entry it is assumed to contain a locked
770 * and referenced buffer which will then be replaced.
772 * If the caller is holding another unrelated buffer locked it must be
773 * passed in reorderbuf so we can properly order buffer locks.
775 * XXX add a flag for the buffer type and check the CRC here XXX
778 hammer_bread(hammer_cluster_t cluster, int32_t cloff,
779 u_int64_t buf_type, int *errorp,
780 struct hammer_buffer **bufferp)
782 hammer_buffer_t buffer;
787 * Load the correct filesystem buffer, replacing *bufferp.
789 buf_no = cloff / HAMMER_BUFSIZE;
791 if (buffer == NULL || buffer->cluster != cluster ||
792 buffer->buf_no != buf_no) {
794 /*hammer_unlock(&buffer->io.lock);*/
795 hammer_rel_buffer(buffer, 0);
797 buffer = hammer_get_buffer(cluster, buf_no, 0, errorp);
801 /*hammer_lock_ex(&buffer->io.lock);*/
805 * Validate the buffer type
807 buf_off = cloff & HAMMER_BUFMASK;
809 if (buf_type != buffer->ondisk->head.buf_type) {
810 kprintf("BUFFER HEAD TYPE MISMATCH %llx %llx\n",
811 buf_type, buffer->ondisk->head.buf_type);
815 if (buf_off < sizeof(buffer->ondisk->head)) {
816 kprintf("BUFFER OFFSET TOO LOW %d\n", buf_off);
823 * Return a pointer to the buffer data.
826 return((char *)buffer->ondisk + buf_off);