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 1.22 2008/01/18 07:02:41 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.
232 hammer_init_cursor_hmp(&cursor, cache, hmp);
233 cursor.key_beg.obj_id = ip->obj_id;
234 cursor.key_beg.key = 0;
235 cursor.key_beg.create_tid = 0;
236 cursor.key_beg.delete_tid = 0;
237 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
238 cursor.key_beg.obj_type = 0;
239 cursor.asof = iinfo.obj_asof;
240 cursor.flags = HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_GET_DATA |
243 *errorp = hammer_btree_lookup(&cursor);
244 if (*errorp == EDEADLK) {
245 hammer_done_cursor(&cursor);
250 * On success the B-Tree lookup will hold the appropriate
251 * buffer cache buffers and provide a pointer to the requested
252 * information. Copy the information to the in-memory inode
253 * and cache the B-Tree node to improve future operations.
256 ip->ino_rec = cursor.record->inode;
257 ip->ino_data = cursor.data->inode;
258 hammer_cache_node(cursor.node, &ip->cache[0]);
260 hammer_cache_node(cursor.node, cache);
264 * On success load the inode's record and data and insert the
265 * inode into the B-Tree. It is possible to race another lookup
266 * insertion of the same inode so deal with that condition too.
268 * The cursor's locked node interlocks against others creating and
269 * destroying ip while we were blocked.
272 hammer_ref(&ip->lock);
273 if (RB_INSERT(hammer_ino_rb_tree, &hmp->rb_inos_root, ip)) {
274 hammer_uncache_node(&ip->cache[0]);
275 hammer_uncache_node(&ip->cache[1]);
276 hammer_unref(&ip->lock);
277 --hammer_count_inodes;
279 hammer_done_cursor(&cursor);
282 ip->flags |= HAMMER_INODE_ONDISK;
284 --hammer_count_inodes;
288 hammer_done_cursor(&cursor);
293 * Create a new filesystem object, returning the inode in *ipp. The
294 * returned inode will be referenced but not locked.
296 * The inode is created in-memory and will be delay-synchronized to the
300 hammer_create_inode(hammer_transaction_t trans, struct vattr *vap,
301 struct ucred *cred, hammer_inode_t dip,
302 struct hammer_inode **ipp)
309 ip = kmalloc(sizeof(*ip), M_HAMMER, M_WAITOK|M_ZERO);
310 ++hammer_count_inodes;
311 ip->obj_id = hammer_alloc_tid(trans);
312 KKASSERT(ip->obj_id != 0);
313 ip->obj_asof = hmp->asof;
315 ip->flags = HAMMER_INODE_DDIRTY | HAMMER_INODE_RDIRTY |
317 ip->last_tid = trans->tid;
319 RB_INIT(&ip->rec_tree);
321 ip->ino_rec.ino_atime = trans->tid;
322 ip->ino_rec.ino_mtime = trans->tid;
323 ip->ino_rec.ino_size = 0;
324 ip->ino_rec.ino_nlinks = 0;
326 ip->ino_rec.base.rec_id = hammer_alloc_recid(trans);
327 KKASSERT(ip->ino_rec.base.rec_id != 0);
328 ip->ino_rec.base.base.btype = HAMMER_BTREE_TYPE_RECORD;
329 ip->ino_rec.base.base.obj_id = ip->obj_id;
330 ip->ino_rec.base.base.key = 0;
331 ip->ino_rec.base.base.create_tid = trans->tid;
332 ip->ino_rec.base.base.delete_tid = 0;
333 ip->ino_rec.base.base.rec_type = HAMMER_RECTYPE_INODE;
334 ip->ino_rec.base.base.obj_type = hammer_get_obj_type(vap->va_type);
336 ip->ino_data.version = HAMMER_INODE_DATA_VERSION;
337 ip->ino_data.mode = vap->va_mode;
338 ip->ino_data.ctime = trans->tid;
339 ip->ino_data.parent_obj_id = (dip) ? dip->ino_rec.base.base.obj_id : 0;
341 switch(ip->ino_rec.base.base.obj_type) {
342 case HAMMER_OBJTYPE_CDEV:
343 case HAMMER_OBJTYPE_BDEV:
344 ip->ino_data.rmajor = vap->va_rmajor;
345 ip->ino_data.rminor = vap->va_rminor;
352 * Calculate default uid/gid and overwrite with information from
355 xuid = hammer_to_unix_xid(&dip->ino_data.uid);
356 ip->ino_data.gid = dip->ino_data.gid;
357 xuid = vop_helper_create_uid(hmp->mp, dip->ino_data.mode, xuid, cred,
359 ip->ino_data.mode = vap->va_mode;
361 if (vap->va_vaflags & VA_UID_UUID_VALID)
362 ip->ino_data.uid = vap->va_uid_uuid;
363 else if (vap->va_uid != (uid_t)VNOVAL)
364 hammer_guid_to_uuid(&ip->ino_data.uid, xuid);
365 if (vap->va_vaflags & VA_GID_UUID_VALID)
366 ip->ino_data.gid = vap->va_gid_uuid;
367 else if (vap->va_gid != (gid_t)VNOVAL)
368 hammer_guid_to_uuid(&ip->ino_data.gid, vap->va_gid);
370 hammer_ref(&ip->lock);
371 if (RB_INSERT(hammer_ino_rb_tree, &hmp->rb_inos_root, ip)) {
372 hammer_unref(&ip->lock);
373 panic("hammer_create_inode: duplicate obj_id %llx", ip->obj_id);
380 * Called by hammer_sync_inode().
383 hammer_update_inode(hammer_inode_t ip)
385 struct hammer_cursor cursor;
386 struct hammer_cursor *spike = NULL;
387 hammer_record_t record;
389 hammer_tid_t last_tid;
392 * Locate the record on-disk and mark it as deleted. Both the B-Tree
393 * node and the record must be marked deleted. The record may or
394 * may not be physically deleted, depending on the retention policy.
396 * If the inode has already been deleted on-disk we have nothing
399 * XXX Update the inode record and data in-place if the retention
402 last_tid = ip->last_tid;
406 if ((ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DELONDISK)) ==
407 HAMMER_INODE_ONDISK) {
408 hammer_init_cursor_hmp(&cursor, &ip->cache[0], ip->hmp);
409 cursor.key_beg.obj_id = ip->obj_id;
410 cursor.key_beg.key = 0;
411 cursor.key_beg.create_tid = 0;
412 cursor.key_beg.delete_tid = 0;
413 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
414 cursor.key_beg.obj_type = 0;
415 cursor.asof = ip->obj_asof;
416 cursor.flags |= HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_ASOF;
418 error = hammer_btree_lookup(&cursor);
421 error = hammer_ip_delete_record(&cursor, last_tid);
423 ip->flags |= HAMMER_INODE_DELONDISK;
424 hammer_cache_node(cursor.node, &ip->cache[0]);
426 hammer_done_cursor(&cursor);
427 if (error == EDEADLK)
432 * Write out a new record if the in-memory inode is not marked
433 * as having been deleted. Update our inode statistics if this
434 * is the first application of the inode on-disk.
436 * If the inode has been deleted permanently, HAMMER_INODE_DELONDISK
437 * will remain set and prevent further updates.
439 if (error == 0 && (ip->flags & HAMMER_INODE_DELETED) == 0) {
440 record = hammer_alloc_mem_record(ip);
441 record->rec.inode = ip->ino_rec;
442 record->rec.inode.base.base.create_tid = last_tid;
443 record->rec.inode.base.data_len = sizeof(ip->ino_data);
444 record->data = (void *)&ip->ino_data;
445 error = hammer_ip_sync_record(record, &spike);
446 record->flags |= HAMMER_RECF_DELETED;
447 hammer_rel_mem_record(record);
448 if (error == ENOSPC) {
449 error = hammer_spike(&spike);
453 KKASSERT(spike == NULL);
455 ip->flags &= ~(HAMMER_INODE_RDIRTY |
456 HAMMER_INODE_DDIRTY |
457 HAMMER_INODE_DELONDISK |
458 HAMMER_INODE_ITIMES);
459 if ((ip->flags & HAMMER_INODE_ONDISK) == 0) {
460 hammer_modify_volume(ip->hmp->rootvol);
461 ++ip->hmp->rootvol->ondisk->vol0_stat_inodes;
462 ip->flags |= HAMMER_INODE_ONDISK;
470 * Update only the itimes fields. This is done no-historically. The
471 * record is updated in-place on the disk.
474 hammer_update_itimes(hammer_inode_t ip)
476 struct hammer_cursor cursor;
477 struct hammer_inode_record *rec;
482 if ((ip->flags & (HAMMER_INODE_ONDISK|HAMMER_INODE_DELONDISK)) ==
483 HAMMER_INODE_ONDISK) {
484 hammer_init_cursor_hmp(&cursor, &ip->cache[0], ip->hmp);
485 cursor.key_beg.obj_id = ip->obj_id;
486 cursor.key_beg.key = 0;
487 cursor.key_beg.create_tid = 0;
488 cursor.key_beg.delete_tid = 0;
489 cursor.key_beg.rec_type = HAMMER_RECTYPE_INODE;
490 cursor.key_beg.obj_type = 0;
491 cursor.asof = ip->obj_asof;
492 cursor.flags |= HAMMER_CURSOR_GET_RECORD | HAMMER_CURSOR_ASOF;
494 error = hammer_btree_lookup(&cursor);
496 rec = &cursor.record->inode;
497 hammer_modify_buffer(cursor.record_buffer);
498 rec->ino_atime = ip->ino_rec.ino_atime;
499 rec->ino_mtime = ip->ino_rec.ino_mtime;
500 ip->flags &= ~HAMMER_INODE_ITIMES;
501 /* XXX recalculate crc */
502 hammer_cache_node(cursor.node, &ip->cache[0]);
504 hammer_done_cursor(&cursor);
505 if (error == EDEADLK)
512 * Release a reference on an inode. If asked to flush the last release
513 * will flush the inode.
516 hammer_rel_inode(struct hammer_inode *ip, int flush)
518 hammer_unref(&ip->lock);
520 ip->flags |= HAMMER_INODE_FLUSH;
521 if (ip->lock.refs == 0) {
522 if (ip->flags & HAMMER_INODE_FLUSH)
523 hammer_unload_inode(ip, (void *)MNT_WAIT);
525 hammer_unload_inode(ip, (void *)MNT_NOWAIT);
530 * Unload and destroy the specified inode.
532 * (called via RB_SCAN)
535 hammer_unload_inode(struct hammer_inode *ip, void *data)
539 KASSERT(ip->lock.refs == 0,
540 ("hammer_unload_inode: %d refs\n", ip->lock.refs));
541 KKASSERT(ip->vp == NULL);
542 hammer_ref(&ip->lock);
544 error = hammer_sync_inode(ip, (int)data, 1);
546 kprintf("hammer_sync_inode failed error %d\n", error);
547 if (ip->lock.refs == 1) {
548 KKASSERT(RB_EMPTY(&ip->rec_tree));
549 RB_REMOVE(hammer_ino_rb_tree, &ip->hmp->rb_inos_root, ip);
551 hammer_uncache_node(&ip->cache[0]);
552 hammer_uncache_node(&ip->cache[1]);
553 --hammer_count_inodes;
556 hammer_unref(&ip->lock);
562 * A transaction has modified an inode, requiring updates as specified by
565 * HAMMER_INODE_RDIRTY: Inode record has been updated
566 * HAMMER_INODE_DDIRTY: Inode data has been updated
567 * HAMMER_INODE_DELETED: Inode record/data must be deleted
568 * HAMMER_INODE_ITIMES: mtime/atime has been updated
570 * last_tid is the TID to use to generate the correct TID when the inode
574 hammer_modify_inode(struct hammer_transaction *trans,
575 struct hammer_inode *ip, int flags)
577 KKASSERT ((ip->flags & HAMMER_INODE_RO) == 0 ||
578 (HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|
579 HAMMER_INODE_DELETED|HAMMER_INODE_ITIMES) == 0);
582 (HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|HAMMER_INODE_DELETED)) {
583 if (hammer_debug_tid) {
584 kprintf("hammer_modify_inode: %016llx (%08x)\n",
585 trans->tid, (int)(trans->tid / 1000000000LL));
587 ip->last_tid = trans->tid;
593 * Sync any dirty buffers and records associated with an inode. The
594 * inode's last_tid field is used as the transaction id for the sync,
595 * overriding any intermediate TIDs that were used for records. Note
596 * that the dirty buffer cache buffers do not have any knowledge of
597 * the transaction id they were modified under.
599 * If we can't sync due to a cluster becoming full the spike structure
600 * will be filled in and ENOSPC returned. We must return -ENOSPC to
601 * terminate the RB_SCAN.
604 hammer_sync_inode_callback(hammer_record_t rec, void *data)
606 struct hammer_cursor **spike = data;
609 hammer_ref(&rec->lock);
610 error = hammer_ip_sync_record(rec, spike);
611 hammer_rel_mem_record(rec);
615 if (error != -ENOSPC) {
616 kprintf("hammer_sync_inode_callback: sync failed rec "
617 "%p, error %d\n", rec, error);
627 hammer_sync_inode(hammer_inode_t ip, int waitfor, int handle_delete)
629 struct hammer_transaction trans;
630 struct hammer_cursor *spike = NULL;
633 if ((ip->flags & HAMMER_INODE_MODMASK) == 0) {
637 hammer_lock_ex(&ip->lock);
640 * Use the transaction id of the last operation to sync.
643 hammer_start_transaction_tid(&trans, ip->hmp, ip->last_tid);
645 hammer_start_transaction(&trans, ip->hmp);
648 * If the inode has been deleted (nlinks == 0), and the OS no longer
649 * has any references to it (handle_delete != 0), clean up in-memory
652 * NOTE: We do not set the RDIRTY flag when updating the delete_tid,
653 * setting HAMMER_INODE_DELETED takes care of it.
655 * NOTE: Because we may sync records within this new transaction,
656 * force the inode update later on to use our transaction id or
657 * the delete_tid of the inode may be less then the create_tid of
658 * the inode update. XXX shouldn't happen but don't take the chance.
660 * NOTE: The call to hammer_ip_delete_range() cannot return ENOSPC
661 * so we can pass a NULL spike structure, because no partial data
662 * deletion can occur (yet).
664 if (ip->ino_rec.ino_nlinks == 0 && handle_delete &&
665 (ip->flags & HAMMER_INODE_GONE) == 0) {
666 ip->flags |= HAMMER_INODE_GONE;
668 vtruncbuf(ip->vp, 0, HAMMER_BUFSIZE);
669 error = hammer_ip_delete_range_all(&trans, ip);
670 KKASSERT(RB_EMPTY(&ip->rec_tree));
671 ip->ino_rec.base.base.delete_tid = trans.tid;
672 hammer_modify_inode(&trans, ip, HAMMER_INODE_DELETED);
673 hammer_modify_volume(ip->hmp->rootvol);
674 --ip->hmp->rootvol->ondisk->vol0_stat_inodes;
678 * Sync the buffer cache.
680 if (ip->vp != NULL) {
681 error = vfsync(ip->vp, waitfor, 1, NULL, NULL);
682 if (RB_ROOT(&ip->vp->v_rbdirty_tree) == NULL)
683 ip->flags &= ~HAMMER_INODE_BUFS;
690 * Now sync related records
693 error = RB_SCAN(hammer_rec_rb_tree, &ip->rec_tree, NULL,
694 hammer_sync_inode_callback, &spike);
695 KKASSERT(error <= 0);
698 if (error == ENOSPC) {
699 error = hammer_spike(&spike);
705 if (RB_EMPTY(&ip->rec_tree))
706 ip->flags &= ~HAMMER_INODE_XDIRTY;
709 * Now update the inode's on-disk inode-data and/or on-disk record.
711 switch(ip->flags & (HAMMER_INODE_DELETED|HAMMER_INODE_ONDISK)) {
712 case HAMMER_INODE_DELETED|HAMMER_INODE_ONDISK:
714 * If deleted and on-disk, don't set any additional flags.
715 * the delete flag takes care of things.
718 case HAMMER_INODE_DELETED:
720 * Take care of the case where a deleted inode was never
721 * flushed to the disk in the first place.
723 ip->flags &= ~(HAMMER_INODE_RDIRTY|HAMMER_INODE_DDIRTY|
724 HAMMER_INODE_XDIRTY|HAMMER_INODE_ITIMES);
725 while (RB_ROOT(&ip->rec_tree)) {
726 hammer_record_t rec = RB_ROOT(&ip->rec_tree);
727 hammer_ref(&rec->lock);
728 rec->flags |= HAMMER_RECF_DELETED;
729 hammer_rel_mem_record(rec);
732 case HAMMER_INODE_ONDISK:
734 * If already on-disk, do not set any additional flags.
739 * If not on-disk and not deleted, set both dirty flags
740 * to force an initial record to be written.
742 ip->flags |= HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY;
747 * If RDIRTY or DDIRTY is set, write out a new record. If the inode
748 * is already on-disk the old record is marked as deleted.
750 * If DELETED is set hammer_update_inode() will delete the existing
751 * record without writing out a new one.
753 * If *ONLY* the ITIMES flag is set we can update the record in-place.
755 if ((ip->flags & (HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY |
756 HAMMER_INODE_ITIMES | HAMMER_INODE_DELETED)) ==
757 HAMMER_INODE_ITIMES) {
758 error = hammer_update_itimes(ip);
760 if (ip->flags & (HAMMER_INODE_RDIRTY | HAMMER_INODE_DDIRTY |
761 HAMMER_INODE_ITIMES | HAMMER_INODE_DELETED)) {
762 error = hammer_update_inode(ip);
764 hammer_commit_transaction(&trans);
765 hammer_unlock(&ip->lock);
770 * Access the filesystem buffer containing the cluster-relative byte
771 * offset, validate the buffer type, load *bufferp and return a
772 * pointer to the requested data. The buffer is reference and locked on
775 * If buf_type is 0 the buffer is assumed to be a pure-data buffer and
776 * no type or crc check is performed.
778 * If *bufferp is not NULL on entry it is assumed to contain a locked
779 * and referenced buffer which will then be replaced.
781 * If the caller is holding another unrelated buffer locked it must be
782 * passed in reorderbuf so we can properly order buffer locks.
784 * XXX add a flag for the buffer type and check the CRC here XXX
787 hammer_bread(hammer_cluster_t cluster, int32_t cloff,
788 u_int64_t buf_type, int *errorp,
789 struct hammer_buffer **bufferp)
791 hammer_buffer_t buffer;
796 * Load the correct filesystem buffer, replacing *bufferp.
798 buf_no = cloff / HAMMER_BUFSIZE;
800 if (buffer == NULL || buffer->cluster != cluster ||
801 buffer->buf_no != buf_no) {
803 /*hammer_unlock(&buffer->io.lock);*/
804 hammer_rel_buffer(buffer, 0);
806 buffer = hammer_get_buffer(cluster, buf_no, 0, errorp);
810 /*hammer_lock_ex(&buffer->io.lock);*/
814 * Validate the buffer type
816 buf_off = cloff & HAMMER_BUFMASK;
818 if (buf_type != buffer->ondisk->head.buf_type) {
819 kprintf("BUFFER HEAD TYPE MISMATCH %llx %llx\n",
820 buf_type, buffer->ondisk->head.buf_type);
824 if (buf_off < sizeof(buffer->ondisk->head)) {
825 kprintf("BUFFER OFFSET TOO LOW %d\n", buf_off);
832 * Return a pointer to the buffer data.
835 return((char *)buffer->ondisk + buf_off);