2 * Copyright (c) 2007-2008 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
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21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/vfs/hammer/hammer_io.c,v 1.41 2008/06/14 01:42:13 dillon Exp $
37 * IO Primitives and buffer cache management
39 * All major data-tracking structures in HAMMER contain a struct hammer_io
40 * which is used to manage their backing store. We use filesystem buffers
41 * for backing store and we leave them passively associated with their
44 * If the kernel tries to destroy a passively associated buf which we cannot
45 * yet let go we set B_LOCKED in the buffer and then actively released it
50 #include <sys/fcntl.h>
51 #include <sys/nlookup.h>
55 static void hammer_io_modify(hammer_io_t io, int count);
56 static void hammer_io_deallocate(struct buf *bp);
59 * Initialize a new, already-zero'd hammer_io structure, or reinitialize
60 * an existing hammer_io structure which may have switched to another type.
63 hammer_io_init(hammer_io_t io, hammer_mount_t hmp, enum hammer_io_type type)
70 * Helper routine to disassociate a buffer cache buffer from an I/O
73 * The io may have 0 or 1 references depending on who called us. The
74 * caller is responsible for dealing with the refs.
76 * This call can only be made when no action is required on the buffer.
77 * HAMMER must own the buffer (released == 0) since we mess around with it.
80 hammer_io_disassociate(hammer_io_structure_t iou, int elseit)
82 struct buf *bp = iou->io.bp;
84 KKASSERT(iou->io.modified == 0);
85 KKASSERT(LIST_FIRST(&bp->b_dep) == (void *)iou);
90 * If the buffer was locked someone wanted to get rid of it.
92 if (bp->b_flags & B_LOCKED) {
93 --hammer_count_io_locked;
94 bp->b_flags &= ~B_LOCKED;
98 * elseit is 0 when called from the kernel path when the io
99 * might have no references.
102 KKASSERT(iou->io.released == 0);
103 iou->io.released = 1;
105 bp->b_flags |= B_NOCACHE|B_RELBUF;
108 KKASSERT(iou->io.released);
112 switch(iou->io.type) {
113 case HAMMER_STRUCTURE_VOLUME:
114 iou->volume.ondisk = NULL;
116 case HAMMER_STRUCTURE_DATA_BUFFER:
117 case HAMMER_STRUCTURE_META_BUFFER:
118 case HAMMER_STRUCTURE_UNDO_BUFFER:
119 iou->buffer.ondisk = NULL;
125 * Wait for any physical IO to complete
128 hammer_io_wait(hammer_io_t io)
132 tsleep_interlock(io);
135 tsleep(io, 0, "hmrflw", 0);
136 if (io->running == 0)
138 tsleep_interlock(io);
140 if (io->running == 0)
148 * Wait for all hammer_io-initated write I/O's to complete. This is not
149 * supposed to count direct I/O's but some can leak through (for
150 * non-full-sized direct I/Os).
153 hammer_io_wait_all(hammer_mount_t hmp, const char *ident)
156 while (hmp->io_running_count)
157 tsleep(&hmp->io_running_count, 0, ident, 0);
161 #define HAMMER_MAXRA 4
164 * Load bp for a HAMMER structure. The io must be exclusively locked by
167 * This routine is mostly used on meta-data and small-data blocks. Generally
168 * speaking HAMMER assumes some locality of reference and will cluster
171 * Note that clustering occurs at the device layer, not the logical layer.
172 * If the buffers do not apply to the current operation they may apply to
176 hammer_io_read(struct vnode *devvp, struct hammer_io *io, hammer_off_t limit)
181 if ((bp = io->bp) == NULL) {
182 ++hammer_count_io_running_read;
183 error = cluster_read(devvp, limit, io->offset,
186 HAMMER_CLUSTER_BUFS, &io->bp);
187 --hammer_count_io_running_read;
190 bp->b_ops = &hammer_bioops;
191 KKASSERT(LIST_FIRST(&bp->b_dep) == NULL);
192 LIST_INSERT_HEAD(&bp->b_dep, &io->worklist, node);
195 KKASSERT(io->modified == 0);
196 KKASSERT(io->running == 0);
197 KKASSERT(io->waiting == 0);
198 io->released = 0; /* we hold an active lock on bp */
206 * Similar to hammer_io_read() but returns a zero'd out buffer instead.
207 * Must be called with the IO exclusively locked.
209 * vfs_bio_clrbuf() is kinda nasty, enforce serialization against background
210 * I/O by forcing the buffer to not be in a released state before calling
213 * This function will also mark the IO as modified but it will not
214 * increment the modify_refs count.
217 hammer_io_new(struct vnode *devvp, struct hammer_io *io)
221 if ((bp = io->bp) == NULL) {
222 io->bp = getblk(devvp, io->offset, HAMMER_BUFSIZE, 0, 0);
224 bp->b_ops = &hammer_bioops;
225 KKASSERT(LIST_FIRST(&bp->b_dep) == NULL);
226 LIST_INSERT_HEAD(&bp->b_dep, &io->worklist, node);
228 KKASSERT(io->running == 0);
238 hammer_io_modify(io, 0);
244 * Remove potential device level aliases against buffers managed by high level
248 hammer_io_inval(hammer_volume_t volume, hammer_off_t zone2_offset)
250 hammer_io_structure_t iou;
251 hammer_off_t phys_offset;
254 phys_offset = volume->ondisk->vol_buf_beg +
255 (zone2_offset & HAMMER_OFF_SHORT_MASK);
256 if (findblk(volume->devvp, phys_offset)) {
257 bp = getblk(volume->devvp, phys_offset, HAMMER_BUFSIZE, 0, 0);
258 if ((iou = (void *)LIST_FIRST(&bp->b_dep)) != NULL) {
259 hammer_io_clear_modify(&iou->io);
262 hammer_io_deallocate(bp);
264 KKASSERT((bp->b_flags & B_LOCKED) == 0);
266 bp->b_flags |= B_NOCACHE|B_RELBUF;
273 * This routine is called on the last reference to a hammer structure.
274 * The io is usually locked exclusively (but may not be during unmount).
276 * This routine is responsible for the disposition of the buffer cache
277 * buffer backing the IO. Only pure-data and undo buffers can be handed
278 * back to the kernel. Volume and meta-data buffers must be retained
279 * by HAMMER until explicitly flushed by the backend.
282 hammer_io_release(struct hammer_io *io, int flush)
284 union hammer_io_structure *iou = (void *)io;
287 if ((bp = io->bp) == NULL)
291 * Try to flush a dirty IO to disk if asked to by the
292 * caller or if the kernel tried to flush the buffer in the past.
294 * Kernel-initiated flushes are only allowed for pure-data buffers.
295 * meta-data and volume buffers can only be flushed explicitly
301 } else if (bp->b_flags & B_LOCKED) {
303 case HAMMER_STRUCTURE_DATA_BUFFER:
304 case HAMMER_STRUCTURE_UNDO_BUFFER:
310 } /* else no explicit request to flush the buffer */
314 * Wait for the IO to complete if asked to.
316 if (io->waitdep && io->running) {
321 * Return control of the buffer to the kernel (with the provisio
322 * that our bioops can override kernel decisions with regards to
325 if ((flush || io->reclaim) && io->modified == 0 && io->running == 0) {
327 * Always disassociate the bp if an explicit flush
328 * was requested and the IO completed with no error
329 * (so unmount can really clean up the structure).
336 hammer_io_disassociate((hammer_io_structure_t)io, 1);
337 } else if (io->modified) {
339 * Only certain IO types can be released to the kernel.
340 * volume and meta-data IO types must be explicitly flushed
344 case HAMMER_STRUCTURE_DATA_BUFFER:
345 case HAMMER_STRUCTURE_UNDO_BUFFER:
346 if (io->released == 0) {
354 } else if (io->released == 0) {
356 * Clean buffers can be generally released to the kernel.
357 * We leave the bp passively associated with the HAMMER
358 * structure and use bioops to disconnect it later on
359 * if the kernel wants to discard the buffer.
361 if (bp->b_flags & B_LOCKED) {
362 hammer_io_disassociate(iou, 1);
365 hammer_io_disassociate(iou, 1);
373 * A released buffer is passively associate with our
374 * hammer_io structure. The kernel cannot destroy it
375 * without making a bioops call. If the kernel (B_LOCKED)
376 * or we (reclaim) requested that the buffer be destroyed
377 * we destroy it, otherwise we do a quick get/release to
378 * reset its position in the kernel's LRU list.
380 * Leaving the buffer passively associated allows us to
381 * use the kernel's LRU buffer flushing mechanisms rather
382 * then rolling our own.
385 if (io->running == 0) {
387 if ((bp->b_flags & B_LOCKED) || io->reclaim) {
389 hammer_io_disassociate(iou, 1);
399 * This routine is called with a locked IO when a flush is desired and
400 * no other references to the structure exists other then ours. This
401 * routine is ONLY called when HAMMER believes it is safe to flush a
402 * potentially modified buffer out.
405 hammer_io_flush(struct hammer_io *io)
410 * Degenerate case - nothing to flush if nothing is dirty.
412 if (io->modified == 0) {
417 KKASSERT(io->modify_refs <= 0);
420 * Acquire ownership of the bp, particularly before we clear our
423 * We are going to bawrite() this bp. Don't leave a window where
424 * io->released is set, we actually own the bp rather then our
430 /* BUF_KERNPROC(io->bp); */
431 /* io->released = 0; */
432 KKASSERT(io->released);
433 KKASSERT(io->bp == bp);
438 * Acquire exclusive access to the bp and then clear the modified
439 * state of the buffer prior to issuing I/O to interlock any
440 * modifications made while the I/O is in progress. This shouldn't
441 * happen anyway but losing data would be worse. The modified bit
442 * will be rechecked after the IO completes.
444 * This is only legal when lock.refs == 1 (otherwise we might clear
445 * the modified bit while there are still users of the cluster
446 * modifying the data).
448 * Do this before potentially blocking so any attempt to modify the
449 * ondisk while we are blocked blocks waiting for us.
451 hammer_io_clear_modify(io);
454 * Transfer ownership to the kernel and initiate I/O.
457 ++io->hmp->io_running_count;
458 ++hammer_count_io_running_write;
462 /************************************************************************
464 ************************************************************************
466 * These routines deal with dependancies created when IO buffers get
467 * modified. The caller must call hammer_modify_*() on a referenced
468 * HAMMER structure prior to modifying its on-disk data.
470 * Any intent to modify an IO buffer acquires the related bp and imposes
471 * various write ordering dependancies.
475 * Mark a HAMMER structure as undergoing modification. Meta-data buffers
476 * are locked until the flusher can deal with them, pure data buffers
477 * can be written out.
481 hammer_io_modify(hammer_io_t io, int count)
483 struct hammer_mount *hmp = io->hmp;
486 * io->modify_refs must be >= 0
488 while (io->modify_refs < 0) {
490 tsleep(io, 0, "hmrmod", 0);
494 * Shortcut if nothing to do.
496 KKASSERT(io->lock.refs != 0 && io->bp != NULL);
497 io->modify_refs += count;
498 if (io->modified && io->released == 0)
501 hammer_lock_ex(&io->lock);
502 if (io->modified == 0) {
503 KKASSERT(io->mod_list == NULL);
505 case HAMMER_STRUCTURE_VOLUME:
506 io->mod_list = &hmp->volu_list;
507 ++hmp->locked_dirty_count;
508 ++hammer_count_dirtybufs;
510 case HAMMER_STRUCTURE_META_BUFFER:
511 io->mod_list = &hmp->meta_list;
512 ++hmp->locked_dirty_count;
513 ++hammer_count_dirtybufs;
515 case HAMMER_STRUCTURE_UNDO_BUFFER:
516 io->mod_list = &hmp->undo_list;
518 case HAMMER_STRUCTURE_DATA_BUFFER:
519 io->mod_list = &hmp->data_list;
522 TAILQ_INSERT_TAIL(io->mod_list, io, mod_entry);
527 BUF_KERNPROC(io->bp);
529 KKASSERT(io->modified != 0);
531 hammer_unlock(&io->lock);
536 hammer_io_modify_done(hammer_io_t io)
538 KKASSERT(io->modify_refs > 0);
540 if (io->modify_refs == 0 && io->waitmod) {
547 hammer_io_write_interlock(hammer_io_t io)
549 while (io->modify_refs != 0) {
551 tsleep(io, 0, "hmrmod", 0);
553 io->modify_refs = -1;
557 hammer_io_done_interlock(hammer_io_t io)
559 KKASSERT(io->modify_refs == -1);
568 * Caller intends to modify a volume's ondisk structure.
570 * This is only allowed if we are the flusher or we have a ref on the
574 hammer_modify_volume(hammer_transaction_t trans, hammer_volume_t volume,
577 KKASSERT (trans == NULL || trans->sync_lock_refs > 0);
579 hammer_io_modify(&volume->io, 1);
581 intptr_t rel_offset = (intptr_t)base - (intptr_t)volume->ondisk;
582 KKASSERT((rel_offset & ~(intptr_t)HAMMER_BUFMASK) == 0);
583 hammer_generate_undo(trans, &volume->io,
584 HAMMER_ENCODE_RAW_VOLUME(volume->vol_no, rel_offset),
590 * Caller intends to modify a buffer's ondisk structure.
592 * This is only allowed if we are the flusher or we have a ref on the
596 hammer_modify_buffer(hammer_transaction_t trans, hammer_buffer_t buffer,
599 KKASSERT (trans == NULL || trans->sync_lock_refs > 0);
601 hammer_io_modify(&buffer->io, 1);
603 intptr_t rel_offset = (intptr_t)base - (intptr_t)buffer->ondisk;
604 KKASSERT((rel_offset & ~(intptr_t)HAMMER_BUFMASK) == 0);
605 hammer_generate_undo(trans, &buffer->io,
606 buffer->zone2_offset + rel_offset,
612 hammer_modify_volume_done(hammer_volume_t volume)
614 hammer_io_modify_done(&volume->io);
618 hammer_modify_buffer_done(hammer_buffer_t buffer)
620 hammer_io_modify_done(&buffer->io);
624 * Mark an entity as not being dirty any more.
627 hammer_io_clear_modify(struct hammer_io *io)
630 KKASSERT(io->mod_list != NULL);
631 if (io->mod_list == &io->hmp->volu_list ||
632 io->mod_list == &io->hmp->meta_list) {
633 --io->hmp->locked_dirty_count;
634 --hammer_count_dirtybufs;
636 TAILQ_REMOVE(io->mod_list, io, mod_entry);
643 * Clear the IO's modify list. Even though the IO is no longer modified
644 * it may still be on the lose_list. This routine is called just before
645 * the governing hammer_buffer is destroyed.
648 hammer_io_clear_modlist(struct hammer_io *io)
651 crit_enter(); /* biodone race against list */
652 KKASSERT(io->mod_list == &io->hmp->lose_list);
653 TAILQ_REMOVE(io->mod_list, io, mod_entry);
659 /************************************************************************
661 ************************************************************************
666 * Pre-IO initiation kernel callback - cluster build only
669 hammer_io_start(struct buf *bp)
674 * Post-IO completion kernel callback - MAY BE CALLED FROM INTERRUPT!
676 * NOTE: HAMMER may modify a buffer after initiating I/O. The modified bit
677 * may also be set if we were marking a cluster header open. Only remove
678 * our dependancy if the modified bit is clear.
681 hammer_io_complete(struct buf *bp)
683 union hammer_io_structure *iou = (void *)LIST_FIRST(&bp->b_dep);
685 KKASSERT(iou->io.released == 1);
688 * Deal with people waiting for I/O to drain
690 if (iou->io.running) {
691 --hammer_count_io_running_write;
692 if (--iou->io.hmp->io_running_count == 0)
693 wakeup(&iou->io.hmp->io_running_count);
694 KKASSERT(iou->io.hmp->io_running_count >= 0);
698 if (iou->io.waiting) {
704 * If B_LOCKED is set someone wanted to deallocate the bp at some
705 * point, do it now if refs has become zero.
707 if ((bp->b_flags & B_LOCKED) && iou->io.lock.refs == 0) {
708 KKASSERT(iou->io.modified == 0);
709 --hammer_count_io_locked;
710 bp->b_flags &= ~B_LOCKED;
711 hammer_io_deallocate(bp);
712 /* structure may be dead now */
717 * Callback from kernel when it wishes to deallocate a passively
718 * associated structure. This mostly occurs with clean buffers
719 * but it may be possible for a holding structure to be marked dirty
720 * while its buffer is passively associated. The caller owns the bp.
722 * If we cannot disassociate we set B_LOCKED to prevent the buffer
723 * from getting reused.
725 * WARNING: Because this can be called directly by getnewbuf we cannot
726 * recurse into the tree. If a bp cannot be immediately disassociated
727 * our only recourse is to set B_LOCKED.
729 * WARNING: This may be called from an interrupt via hammer_io_complete()
732 hammer_io_deallocate(struct buf *bp)
734 hammer_io_structure_t iou = (void *)LIST_FIRST(&bp->b_dep);
736 KKASSERT((bp->b_flags & B_LOCKED) == 0 && iou->io.running == 0);
737 if (iou->io.lock.refs > 0 || iou->io.modified) {
739 * It is not legal to disassociate a modified buffer. This
740 * case really shouldn't ever occur.
742 bp->b_flags |= B_LOCKED;
743 ++hammer_count_io_locked;
746 * Disassociate the BP. If the io has no refs left we
747 * have to add it to the loose list.
749 hammer_io_disassociate(iou, 0);
750 if (iou->io.bp == NULL &&
751 iou->io.type != HAMMER_STRUCTURE_VOLUME) {
752 KKASSERT(iou->io.mod_list == NULL);
753 crit_enter(); /* biodone race against list */
754 iou->io.mod_list = &iou->io.hmp->lose_list;
755 TAILQ_INSERT_TAIL(iou->io.mod_list, &iou->io, mod_entry);
762 hammer_io_fsync(struct vnode *vp)
768 * NOTE: will not be called unless we tell the kernel about the
769 * bioops. Unused... we use the mount's VFS_SYNC instead.
772 hammer_io_sync(struct mount *mp)
778 hammer_io_movedeps(struct buf *bp1, struct buf *bp2)
783 * I/O pre-check for reading and writing. HAMMER only uses this for
784 * B_CACHE buffers so checkread just shouldn't happen, but if it does
787 * Writing is a different case. We don't want the kernel to try to write
788 * out a buffer that HAMMER may be modifying passively or which has a
789 * dependancy. In addition, kernel-demanded writes can only proceed for
790 * certain types of buffers (i.e. UNDO and DATA types). Other dirty
791 * buffer types can only be explicitly written by the flusher.
793 * checkwrite will only be called for bdwrite()n buffers. If we return
794 * success the kernel is guaranteed to initiate the buffer write.
797 hammer_io_checkread(struct buf *bp)
803 hammer_io_checkwrite(struct buf *bp)
805 hammer_io_t io = (void *)LIST_FIRST(&bp->b_dep);
808 * This shouldn't happen under normal operation.
810 if (io->type == HAMMER_STRUCTURE_VOLUME ||
811 io->type == HAMMER_STRUCTURE_META_BUFFER) {
813 panic("hammer_io_checkwrite: illegal buffer");
814 if ((bp->b_flags & B_LOCKED) == 0) {
815 bp->b_flags |= B_LOCKED;
816 ++hammer_count_io_locked;
822 * We can only clear the modified bit if the IO is not currently
823 * undergoing modification. Otherwise we may miss changes.
825 if (io->modify_refs == 0 && io->modified)
826 hammer_io_clear_modify(io);
829 * The kernel is going to start the IO, set io->running.
831 KKASSERT(io->running == 0);
833 ++io->hmp->io_running_count;
834 ++hammer_count_io_running_write;
839 * Return non-zero if we wish to delay the kernel's attempt to flush
840 * this buffer to disk.
843 hammer_io_countdeps(struct buf *bp, int n)
848 struct bio_ops hammer_bioops = {
849 .io_start = hammer_io_start,
850 .io_complete = hammer_io_complete,
851 .io_deallocate = hammer_io_deallocate,
852 .io_fsync = hammer_io_fsync,
853 .io_sync = hammer_io_sync,
854 .io_movedeps = hammer_io_movedeps,
855 .io_countdeps = hammer_io_countdeps,
856 .io_checkread = hammer_io_checkread,
857 .io_checkwrite = hammer_io_checkwrite,
860 /************************************************************************
862 ************************************************************************
864 * These functions operate directly on the buffer cache buffer associated
865 * with a front-end vnode rather then a back-end device vnode.
869 * Read a buffer associated with a front-end vnode directly from the
870 * disk media. The bio may be issued asynchronously.
872 * This function can takes a zone-2 or zone-X blockmap offset.
875 hammer_io_direct_read(hammer_mount_t hmp, hammer_off_t data_offset,
878 hammer_off_t zone2_offset;
879 hammer_volume_t volume;
885 if ((data_offset & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_RAW_BUFFER) {
886 zone2_offset = data_offset;
889 KKASSERT(data_offset >= HAMMER_ZONE_BTREE);
890 KKASSERT((data_offset & HAMMER_BUFMASK) == 0);
891 zone2_offset = hammer_blockmap_lookup(hmp, data_offset, &error);
894 vol_no = HAMMER_VOL_DECODE(zone2_offset);
895 volume = hammer_get_volume(hmp, vol_no, &error);
896 if (error == 0 && zone2_offset >= volume->maxbuf_off)
899 zone2_offset &= HAMMER_OFF_SHORT_MASK;
900 nbio = push_bio(bio);
901 nbio->bio_offset = volume->ondisk->vol_buf_beg +
903 vn_strategy(volume->devvp, nbio);
905 hammer_rel_volume(volume, 0);
908 kprintf("hammer_direct_read: failed @ %016llx\n",
912 bp->b_flags |= B_ERROR;
919 * Write a buffer associated with a front-end vnode directly to the
920 * disk media. The bio may be issued asynchronously.
923 hammer_io_direct_write(hammer_mount_t hmp, hammer_btree_leaf_elm_t leaf,
926 hammer_off_t buf_offset;
927 hammer_off_t zone2_offset;
928 hammer_volume_t volume;
929 hammer_buffer_t buffer;
936 buf_offset = leaf->data_offset;
938 KKASSERT(buf_offset > HAMMER_ZONE_BTREE);
939 KKASSERT(bio->bio_buf->b_cmd == BUF_CMD_WRITE);
941 if ((buf_offset & HAMMER_BUFMASK) == 0 &&
942 leaf->data_len == HAMMER_BUFSIZE) {
944 * We are using the vnode's bio to write directly to the
945 * media, any hammer_buffer at the same zone-X offset will
946 * now have stale data.
948 zone2_offset = hammer_blockmap_lookup(hmp, buf_offset, &error);
949 vol_no = HAMMER_VOL_DECODE(zone2_offset);
950 volume = hammer_get_volume(hmp, vol_no, &error);
952 if (error == 0 && zone2_offset >= volume->maxbuf_off)
955 hammer_del_buffers(hmp, buf_offset,
956 zone2_offset, HAMMER_BUFSIZE);
958 KKASSERT(bp->b_bufsize == HAMMER_BUFSIZE);
959 zone2_offset &= HAMMER_OFF_SHORT_MASK;
961 nbio = push_bio(bio);
962 nbio->bio_offset = volume->ondisk->vol_buf_beg +
964 vn_strategy(volume->devvp, nbio);
966 hammer_rel_volume(volume, 0);
968 KKASSERT(((buf_offset ^ (buf_offset + leaf->data_len - 1)) & ~HAMMER_BUFMASK64) == 0);
970 ptr = hammer_bread(hmp, buf_offset, &error, &buffer);
973 bp->b_flags |= B_AGE;
974 hammer_io_modify(&buffer->io, 1);
975 bcopy(bp->b_data, ptr, leaf->data_len);
976 hammer_io_modify_done(&buffer->io);
977 hammer_rel_buffer(buffer, 0);
983 kprintf("hammer_direct_write: failed @ %016llx\n",
988 bp->b_flags |= B_ERROR;