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
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_io.c,v 1.55 2008/09/15 17:02:49 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
);
58 static void hammer_io_direct_read_complete(struct bio
*nbio
);
60 static void hammer_io_direct_write_complete(struct bio
*nbio
);
61 static int hammer_io_direct_uncache_callback(hammer_inode_t ip
, void *data
);
62 static void hammer_io_set_modlist(struct hammer_io
*io
);
63 static void hammer_io_flush_mark(hammer_volume_t volume
);
67 * Initialize a new, already-zero'd hammer_io structure, or reinitialize
68 * an existing hammer_io structure which may have switched to another type.
71 hammer_io_init(hammer_io_t io
, hammer_volume_t volume
, enum hammer_io_type type
)
74 io
->hmp
= volume
->io
.hmp
;
79 * Helper routine to disassociate a buffer cache buffer from an I/O
80 * structure. The buffer is unlocked and marked appropriate for reclamation.
82 * The io may have 0 or 1 references depending on who called us. The
83 * caller is responsible for dealing with the refs.
85 * This call can only be made when no action is required on the buffer.
87 * The caller must own the buffer and the IO must indicate that the
88 * structure no longer owns it (io.released != 0).
91 hammer_io_disassociate(hammer_io_structure_t iou
)
93 struct buf
*bp
= iou
->io
.bp
;
95 KKASSERT(iou
->io
.released
);
96 KKASSERT(iou
->io
.modified
== 0);
97 KKASSERT(LIST_FIRST(&bp
->b_dep
) == (void *)iou
);
102 * If the buffer was locked someone wanted to get rid of it.
104 if (bp
->b_flags
& B_LOCKED
) {
105 --hammer_count_io_locked
;
106 bp
->b_flags
&= ~B_LOCKED
;
108 if (iou
->io
.reclaim
) {
109 bp
->b_flags
|= B_NOCACHE
|B_RELBUF
;
113 switch(iou
->io
.type
) {
114 case HAMMER_STRUCTURE_VOLUME
:
115 iou
->volume
.ondisk
= NULL
;
117 case HAMMER_STRUCTURE_DATA_BUFFER
:
118 case HAMMER_STRUCTURE_META_BUFFER
:
119 case HAMMER_STRUCTURE_UNDO_BUFFER
:
120 iou
->buffer
.ondisk
= NULL
;
126 * Wait for any physical IO to complete
128 * XXX we aren't interlocked against a spinlock or anything so there
129 * is a small window in the interlock / io->running == 0 test.
132 hammer_io_wait(hammer_io_t io
)
137 tsleep_interlock(io
, 0);
138 if (io
->running
== 0)
140 tsleep(io
, PINTERLOCKED
, "hmrflw", hz
);
141 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
)
155 hammer_io_flush_sync(hmp
);
157 while (hmp
->io_running_space
)
158 tsleep(&hmp
->io_running_space
, 0, ident
, 0);
162 #define HAMMER_MAXRA 4
165 * Load bp for a HAMMER structure. The io must be exclusively locked by
168 * This routine is mostly used on meta-data and small-data blocks. Generally
169 * speaking HAMMER assumes some locality of reference and will cluster
172 * Note that clustering occurs at the device layer, not the logical layer.
173 * If the buffers do not apply to the current operation they may apply to
177 hammer_io_read(struct vnode
*devvp
, struct hammer_io
*io
, hammer_off_t limit
)
182 if ((bp
= io
->bp
) == NULL
) {
183 hammer_count_io_running_read
+= io
->bytes
;
184 if (hammer_cluster_enable
) {
185 error
= cluster_read(devvp
, limit
,
186 io
->offset
, io
->bytes
,
188 HAMMER_CLUSTER_BUFS
, &io
->bp
);
190 error
= bread(devvp
, io
->offset
, io
->bytes
, &io
->bp
);
192 hammer_stats_disk_read
+= io
->bytes
;
193 hammer_count_io_running_read
-= io
->bytes
;
196 * The code generally assumes b_ops/b_dep has been set-up,
197 * even if we error out here.
200 bp
->b_ops
= &hammer_bioops
;
201 KKASSERT(LIST_FIRST(&bp
->b_dep
) == NULL
);
202 LIST_INSERT_HEAD(&bp
->b_dep
, &io
->worklist
, node
);
204 KKASSERT(io
->modified
== 0);
205 KKASSERT(io
->running
== 0);
206 KKASSERT(io
->waiting
== 0);
207 io
->released
= 0; /* we hold an active lock on bp */
215 * Similar to hammer_io_read() but returns a zero'd out buffer instead.
216 * Must be called with the IO exclusively locked.
218 * vfs_bio_clrbuf() is kinda nasty, enforce serialization against background
219 * I/O by forcing the buffer to not be in a released state before calling
222 * This function will also mark the IO as modified but it will not
223 * increment the modify_refs count.
226 hammer_io_new(struct vnode
*devvp
, struct hammer_io
*io
)
230 if ((bp
= io
->bp
) == NULL
) {
231 io
->bp
= getblk(devvp
, io
->offset
, io
->bytes
, 0, 0);
233 bp
->b_ops
= &hammer_bioops
;
234 KKASSERT(LIST_FIRST(&bp
->b_dep
) == NULL
);
235 LIST_INSERT_HEAD(&bp
->b_dep
, &io
->worklist
, node
);
237 KKASSERT(io
->running
== 0);
247 hammer_io_modify(io
, 0);
253 * Remove potential device level aliases against buffers managed by high level
254 * vnodes. Aliases can also be created due to mixed buffer sizes or via
255 * direct access to the backing store device.
257 * This is nasty because the buffers are also VMIO-backed. Even if a buffer
258 * does not exist its backing VM pages might, and we have to invalidate
259 * those as well or a getblk() will reinstate them.
261 * Buffer cache buffers associated with hammer_buffers cannot be
265 hammer_io_inval(hammer_volume_t volume
, hammer_off_t zone2_offset
)
267 hammer_io_structure_t iou
;
268 hammer_off_t phys_offset
;
272 phys_offset
= volume
->ondisk
->vol_buf_beg
+
273 (zone2_offset
& HAMMER_OFF_SHORT_MASK
);
275 if ((bp
= findblk(volume
->devvp
, phys_offset
, FINDBLK_TEST
)) != NULL
)
276 bp
= getblk(volume
->devvp
, phys_offset
, bp
->b_bufsize
, 0, 0);
278 bp
= getblk(volume
->devvp
, phys_offset
, HAMMER_BUFSIZE
, 0, 0);
279 if ((iou
= (void *)LIST_FIRST(&bp
->b_dep
)) != NULL
) {
281 hammer_ref(&iou
->io
.lock
);
282 hammer_io_clear_modify(&iou
->io
, 1);
284 iou
->io
.released
= 0;
288 KKASSERT(iou
->io
.lock
.refs
== 1);
289 hammer_rel_buffer(&iou
->buffer
, 0);
290 /*hammer_io_deallocate(bp);*/
295 KKASSERT((bp
->b_flags
& B_LOCKED
) == 0);
297 bp
->b_flags
|= B_NOCACHE
|B_RELBUF
;
306 * This routine is called on the last reference to a hammer structure.
307 * The io is usually interlocked with io.loading and io.refs must be 1.
309 * This routine may return a non-NULL bp to the caller for dispoal. Disposal
310 * simply means the caller finishes decrementing the ref-count on the
311 * IO structure then brelse()'s the bp. The bp may or may not still be
312 * passively associated with the IO.
314 * The only requirement here is that modified meta-data and volume-header
315 * buffer may NOT be disassociated from the IO structure, and consequently
316 * we also leave such buffers actively associated with the IO if they already
317 * are (since the kernel can't do anything with them anyway). Only the
318 * flusher is allowed to write such buffers out. Modified pure-data and
319 * undo buffers are returned to the kernel but left passively associated
320 * so we can track when the kernel writes the bp out.
323 hammer_io_release(struct hammer_io
*io
, int flush
)
325 union hammer_io_structure
*iou
= (void *)io
;
328 if ((bp
= io
->bp
) == NULL
)
332 * Try to flush a dirty IO to disk if asked to by the
333 * caller or if the kernel tried to flush the buffer in the past.
335 * Kernel-initiated flushes are only allowed for pure-data buffers.
336 * meta-data and volume buffers can only be flushed explicitly
342 } else if (bp
->b_flags
& B_LOCKED
) {
344 case HAMMER_STRUCTURE_DATA_BUFFER
:
345 case HAMMER_STRUCTURE_UNDO_BUFFER
:
351 } /* else no explicit request to flush the buffer */
355 * Wait for the IO to complete if asked to. This occurs when
356 * the buffer must be disposed of definitively during an umount
357 * or buffer invalidation.
359 if (io
->waitdep
&& io
->running
) {
364 * Return control of the buffer to the kernel (with the provisio
365 * that our bioops can override kernel decisions with regards to
368 if ((flush
|| io
->reclaim
) && io
->modified
== 0 && io
->running
== 0) {
370 * Always disassociate the bp if an explicit flush
371 * was requested and the IO completed with no error
372 * (so unmount can really clean up the structure).
380 hammer_io_disassociate((hammer_io_structure_t
)io
);
382 } else if (io
->modified
) {
384 * Only certain IO types can be released to the kernel if
385 * the buffer has been modified.
387 * volume and meta-data IO types may only be explicitly
391 case HAMMER_STRUCTURE_DATA_BUFFER
:
392 case HAMMER_STRUCTURE_UNDO_BUFFER
:
393 if (io
->released
== 0) {
401 bp
= NULL
; /* bp left associated */
402 } else if (io
->released
== 0) {
404 * Clean buffers can be generally released to the kernel.
405 * We leave the bp passively associated with the HAMMER
406 * structure and use bioops to disconnect it later on
407 * if the kernel wants to discard the buffer.
409 * We can steal the structure's ownership of the bp.
412 if (bp
->b_flags
& B_LOCKED
) {
413 hammer_io_disassociate(iou
);
417 hammer_io_disassociate(iou
);
420 /* return the bp (bp passively associated) */
425 * A released buffer is passively associate with our
426 * hammer_io structure. The kernel cannot destroy it
427 * without making a bioops call. If the kernel (B_LOCKED)
428 * or we (reclaim) requested that the buffer be destroyed
429 * we destroy it, otherwise we do a quick get/release to
430 * reset its position in the kernel's LRU list.
432 * Leaving the buffer passively associated allows us to
433 * use the kernel's LRU buffer flushing mechanisms rather
434 * then rolling our own.
436 * XXX there are two ways of doing this. We can re-acquire
437 * and passively release to reset the LRU, or not.
439 if (io
->running
== 0) {
441 if ((bp
->b_flags
& B_LOCKED
) || io
->reclaim
) {
442 hammer_io_disassociate(iou
);
445 /* return the bp (bp passively associated) */
449 * bp is left passively associated but we do not
450 * try to reacquire it. Interactions with the io
451 * structure will occur on completion of the bp's
461 * This routine is called with a locked IO when a flush is desired and
462 * no other references to the structure exists other then ours. This
463 * routine is ONLY called when HAMMER believes it is safe to flush a
464 * potentially modified buffer out.
467 hammer_io_flush(struct hammer_io
*io
)
472 * Degenerate case - nothing to flush if nothing is dirty.
474 if (io
->modified
== 0) {
479 KKASSERT(io
->modify_refs
<= 0);
482 * Acquire ownership of the bp, particularly before we clear our
485 * We are going to bawrite() this bp. Don't leave a window where
486 * io->released is set, we actually own the bp rather then our
492 /* BUF_KERNPROC(io->bp); */
493 /* io->released = 0; */
494 KKASSERT(io
->released
);
495 KKASSERT(io
->bp
== bp
);
500 * Acquire exclusive access to the bp and then clear the modified
501 * state of the buffer prior to issuing I/O to interlock any
502 * modifications made while the I/O is in progress. This shouldn't
503 * happen anyway but losing data would be worse. The modified bit
504 * will be rechecked after the IO completes.
506 * NOTE: This call also finalizes the buffer's content (inval == 0).
508 * This is only legal when lock.refs == 1 (otherwise we might clear
509 * the modified bit while there are still users of the cluster
510 * modifying the data).
512 * Do this before potentially blocking so any attempt to modify the
513 * ondisk while we are blocked blocks waiting for us.
515 hammer_ref(&io
->lock
);
516 hammer_io_clear_modify(io
, 0);
517 hammer_unref(&io
->lock
);
520 * Transfer ownership to the kernel and initiate I/O.
523 io
->hmp
->io_running_space
+= io
->bytes
;
524 hammer_count_io_running_write
+= io
->bytes
;
526 hammer_io_flush_mark(io
->volume
);
529 /************************************************************************
531 ************************************************************************
533 * These routines deal with dependancies created when IO buffers get
534 * modified. The caller must call hammer_modify_*() on a referenced
535 * HAMMER structure prior to modifying its on-disk data.
537 * Any intent to modify an IO buffer acquires the related bp and imposes
538 * various write ordering dependancies.
542 * Mark a HAMMER structure as undergoing modification. Meta-data buffers
543 * are locked until the flusher can deal with them, pure data buffers
544 * can be written out.
548 hammer_io_modify(hammer_io_t io
, int count
)
551 * io->modify_refs must be >= 0
553 while (io
->modify_refs
< 0) {
555 tsleep(io
, 0, "hmrmod", 0);
559 * Shortcut if nothing to do.
561 KKASSERT(io
->lock
.refs
!= 0 && io
->bp
!= NULL
);
562 io
->modify_refs
+= count
;
563 if (io
->modified
&& io
->released
== 0)
566 hammer_lock_ex(&io
->lock
);
567 if (io
->modified
== 0) {
568 hammer_io_set_modlist(io
);
573 BUF_KERNPROC(io
->bp
);
575 KKASSERT(io
->modified
!= 0);
577 hammer_unlock(&io
->lock
);
582 hammer_io_modify_done(hammer_io_t io
)
584 KKASSERT(io
->modify_refs
> 0);
586 if (io
->modify_refs
== 0 && io
->waitmod
) {
593 hammer_io_write_interlock(hammer_io_t io
)
595 while (io
->modify_refs
!= 0) {
597 tsleep(io
, 0, "hmrmod", 0);
599 io
->modify_refs
= -1;
603 hammer_io_done_interlock(hammer_io_t io
)
605 KKASSERT(io
->modify_refs
== -1);
614 * Caller intends to modify a volume's ondisk structure.
616 * This is only allowed if we are the flusher or we have a ref on the
620 hammer_modify_volume(hammer_transaction_t trans
, hammer_volume_t volume
,
623 KKASSERT (trans
== NULL
|| trans
->sync_lock_refs
> 0);
625 hammer_io_modify(&volume
->io
, 1);
627 intptr_t rel_offset
= (intptr_t)base
- (intptr_t)volume
->ondisk
;
628 KKASSERT((rel_offset
& ~(intptr_t)HAMMER_BUFMASK
) == 0);
629 hammer_generate_undo(trans
, &volume
->io
,
630 HAMMER_ENCODE_RAW_VOLUME(volume
->vol_no
, rel_offset
),
636 * Caller intends to modify a buffer's ondisk structure.
638 * This is only allowed if we are the flusher or we have a ref on the
642 hammer_modify_buffer(hammer_transaction_t trans
, hammer_buffer_t buffer
,
645 KKASSERT (trans
== NULL
|| trans
->sync_lock_refs
> 0);
647 hammer_io_modify(&buffer
->io
, 1);
649 intptr_t rel_offset
= (intptr_t)base
- (intptr_t)buffer
->ondisk
;
650 KKASSERT((rel_offset
& ~(intptr_t)HAMMER_BUFMASK
) == 0);
651 hammer_generate_undo(trans
, &buffer
->io
,
652 buffer
->zone2_offset
+ rel_offset
,
658 hammer_modify_volume_done(hammer_volume_t volume
)
660 hammer_io_modify_done(&volume
->io
);
664 hammer_modify_buffer_done(hammer_buffer_t buffer
)
666 hammer_io_modify_done(&buffer
->io
);
670 * Mark an entity as not being dirty any more and finalize any
671 * delayed adjustments to the buffer.
673 * Delayed adjustments are an important performance enhancement, allowing
674 * us to avoid recalculating B-Tree node CRCs over and over again when
675 * making bulk-modifications to the B-Tree.
677 * If inval is non-zero delayed adjustments are ignored.
679 * This routine may dereference related btree nodes and cause the
680 * buffer to be dereferenced. The caller must own a reference on io.
683 hammer_io_clear_modify(struct hammer_io
*io
, int inval
)
685 if (io
->modified
== 0)
689 * Take us off the mod-list and clear the modified bit.
691 KKASSERT(io
->mod_list
!= NULL
);
692 if (io
->mod_list
== &io
->hmp
->volu_list
||
693 io
->mod_list
== &io
->hmp
->meta_list
) {
694 io
->hmp
->locked_dirty_space
-= io
->bytes
;
695 hammer_count_dirtybufspace
-= io
->bytes
;
697 TAILQ_REMOVE(io
->mod_list
, io
, mod_entry
);
702 * If this bit is not set there are no delayed adjustments.
709 * Finalize requested CRCs. The NEEDSCRC flag also holds a reference
710 * on the node (& underlying buffer). Release the node after clearing
713 if (io
->type
== HAMMER_STRUCTURE_META_BUFFER
) {
714 hammer_buffer_t buffer
= (void *)io
;
718 TAILQ_FOREACH(node
, &buffer
->clist
, entry
) {
719 if ((node
->flags
& HAMMER_NODE_NEEDSCRC
) == 0)
721 node
->flags
&= ~HAMMER_NODE_NEEDSCRC
;
722 KKASSERT(node
->ondisk
);
724 node
->ondisk
->crc
= crc32(&node
->ondisk
->crc
+ 1, HAMMER_BTREE_CRCSIZE
);
725 hammer_rel_node(node
);
729 /* caller must still have ref on io */
730 KKASSERT(io
->lock
.refs
> 0);
734 * Clear the IO's modify list. Even though the IO is no longer modified
735 * it may still be on the lose_list. This routine is called just before
736 * the governing hammer_buffer is destroyed.
739 hammer_io_clear_modlist(struct hammer_io
*io
)
741 KKASSERT(io
->modified
== 0);
743 crit_enter(); /* biodone race against list */
744 KKASSERT(io
->mod_list
== &io
->hmp
->lose_list
);
745 TAILQ_REMOVE(io
->mod_list
, io
, mod_entry
);
752 hammer_io_set_modlist(struct hammer_io
*io
)
754 struct hammer_mount
*hmp
= io
->hmp
;
756 KKASSERT(io
->mod_list
== NULL
);
759 case HAMMER_STRUCTURE_VOLUME
:
760 io
->mod_list
= &hmp
->volu_list
;
761 hmp
->locked_dirty_space
+= io
->bytes
;
762 hammer_count_dirtybufspace
+= io
->bytes
;
764 case HAMMER_STRUCTURE_META_BUFFER
:
765 io
->mod_list
= &hmp
->meta_list
;
766 hmp
->locked_dirty_space
+= io
->bytes
;
767 hammer_count_dirtybufspace
+= io
->bytes
;
769 case HAMMER_STRUCTURE_UNDO_BUFFER
:
770 io
->mod_list
= &hmp
->undo_list
;
772 case HAMMER_STRUCTURE_DATA_BUFFER
:
773 io
->mod_list
= &hmp
->data_list
;
776 TAILQ_INSERT_TAIL(io
->mod_list
, io
, mod_entry
);
779 /************************************************************************
781 ************************************************************************
786 * Pre-IO initiation kernel callback - cluster build only
789 hammer_io_start(struct buf
*bp
)
794 * Post-IO completion kernel callback - MAY BE CALLED FROM INTERRUPT!
796 * NOTE: HAMMER may modify a buffer after initiating I/O. The modified bit
797 * may also be set if we were marking a cluster header open. Only remove
798 * our dependancy if the modified bit is clear.
801 hammer_io_complete(struct buf
*bp
)
803 union hammer_io_structure
*iou
= (void *)LIST_FIRST(&bp
->b_dep
);
805 KKASSERT(iou
->io
.released
== 1);
808 * Deal with people waiting for I/O to drain
810 if (iou
->io
.running
) {
812 * Deal with critical write errors. Once a critical error
813 * has been flagged in hmp the UNDO FIFO will not be updated.
814 * That way crash recover will give us a consistent
817 * Because of this we can throw away failed UNDO buffers. If
818 * we throw away META or DATA buffers we risk corrupting
819 * the now read-only version of the filesystem visible to
820 * the user. Clear B_ERROR so the buffer is not re-dirtied
821 * by the kernel and ref the io so it doesn't get thrown
824 if (bp
->b_flags
& B_ERROR
) {
825 hammer_critical_error(iou
->io
.hmp
, NULL
, bp
->b_error
,
826 "while flushing meta-data");
827 switch(iou
->io
.type
) {
828 case HAMMER_STRUCTURE_UNDO_BUFFER
:
831 if (iou
->io
.ioerror
== 0) {
833 if (iou
->io
.lock
.refs
== 0)
834 ++hammer_count_refedbufs
;
835 hammer_ref(&iou
->io
.lock
);
839 bp
->b_flags
&= ~B_ERROR
;
842 hammer_io_set_modlist(&iou
->io
);
843 iou
->io
.modified
= 1;
846 hammer_stats_disk_write
+= iou
->io
.bytes
;
847 hammer_count_io_running_write
-= iou
->io
.bytes
;
848 iou
->io
.hmp
->io_running_space
-= iou
->io
.bytes
;
849 if (iou
->io
.hmp
->io_running_space
== 0)
850 wakeup(&iou
->io
.hmp
->io_running_space
);
851 KKASSERT(iou
->io
.hmp
->io_running_space
>= 0);
854 hammer_stats_disk_read
+= iou
->io
.bytes
;
857 if (iou
->io
.waiting
) {
863 * If B_LOCKED is set someone wanted to deallocate the bp at some
864 * point, do it now if refs has become zero.
866 if ((bp
->b_flags
& B_LOCKED
) && iou
->io
.lock
.refs
== 0) {
867 KKASSERT(iou
->io
.modified
== 0);
868 --hammer_count_io_locked
;
869 bp
->b_flags
&= ~B_LOCKED
;
870 hammer_io_deallocate(bp
);
871 /* structure may be dead now */
876 * Callback from kernel when it wishes to deallocate a passively
877 * associated structure. This mostly occurs with clean buffers
878 * but it may be possible for a holding structure to be marked dirty
879 * while its buffer is passively associated. The caller owns the bp.
881 * If we cannot disassociate we set B_LOCKED to prevent the buffer
882 * from getting reused.
884 * WARNING: Because this can be called directly by getnewbuf we cannot
885 * recurse into the tree. If a bp cannot be immediately disassociated
886 * our only recourse is to set B_LOCKED.
888 * WARNING: This may be called from an interrupt via hammer_io_complete()
891 hammer_io_deallocate(struct buf
*bp
)
893 hammer_io_structure_t iou
= (void *)LIST_FIRST(&bp
->b_dep
);
895 KKASSERT((bp
->b_flags
& B_LOCKED
) == 0 && iou
->io
.running
== 0);
896 if (iou
->io
.lock
.refs
> 0 || iou
->io
.modified
) {
898 * It is not legal to disassociate a modified buffer. This
899 * case really shouldn't ever occur.
901 bp
->b_flags
|= B_LOCKED
;
902 ++hammer_count_io_locked
;
905 * Disassociate the BP. If the io has no refs left we
906 * have to add it to the loose list.
908 hammer_io_disassociate(iou
);
909 if (iou
->io
.type
!= HAMMER_STRUCTURE_VOLUME
) {
910 KKASSERT(iou
->io
.bp
== NULL
);
911 KKASSERT(iou
->io
.mod_list
== NULL
);
912 crit_enter(); /* biodone race against list */
913 iou
->io
.mod_list
= &iou
->io
.hmp
->lose_list
;
914 TAILQ_INSERT_TAIL(iou
->io
.mod_list
, &iou
->io
, mod_entry
);
921 hammer_io_fsync(struct vnode
*vp
)
927 * NOTE: will not be called unless we tell the kernel about the
928 * bioops. Unused... we use the mount's VFS_SYNC instead.
931 hammer_io_sync(struct mount
*mp
)
937 hammer_io_movedeps(struct buf
*bp1
, struct buf
*bp2
)
942 * I/O pre-check for reading and writing. HAMMER only uses this for
943 * B_CACHE buffers so checkread just shouldn't happen, but if it does
946 * Writing is a different case. We don't want the kernel to try to write
947 * out a buffer that HAMMER may be modifying passively or which has a
948 * dependancy. In addition, kernel-demanded writes can only proceed for
949 * certain types of buffers (i.e. UNDO and DATA types). Other dirty
950 * buffer types can only be explicitly written by the flusher.
952 * checkwrite will only be called for bdwrite()n buffers. If we return
953 * success the kernel is guaranteed to initiate the buffer write.
956 hammer_io_checkread(struct buf
*bp
)
962 hammer_io_checkwrite(struct buf
*bp
)
964 hammer_io_t io
= (void *)LIST_FIRST(&bp
->b_dep
);
967 * This shouldn't happen under normal operation.
969 if (io
->type
== HAMMER_STRUCTURE_VOLUME
||
970 io
->type
== HAMMER_STRUCTURE_META_BUFFER
) {
972 panic("hammer_io_checkwrite: illegal buffer");
973 if ((bp
->b_flags
& B_LOCKED
) == 0) {
974 bp
->b_flags
|= B_LOCKED
;
975 ++hammer_count_io_locked
;
981 * We can only clear the modified bit if the IO is not currently
982 * undergoing modification. Otherwise we may miss changes.
984 * Only data and undo buffers can reach here. These buffers do
985 * not have terminal crc functions but we temporarily reference
986 * the IO anyway, just in case.
988 if (io
->modify_refs
== 0 && io
->modified
) {
989 hammer_ref(&io
->lock
);
990 hammer_io_clear_modify(io
, 0);
991 hammer_unref(&io
->lock
);
992 } else if (io
->modified
) {
993 KKASSERT(io
->type
== HAMMER_STRUCTURE_DATA_BUFFER
);
997 * The kernel is going to start the IO, set io->running.
999 KKASSERT(io
->running
== 0);
1001 io
->hmp
->io_running_space
+= io
->bytes
;
1002 hammer_count_io_running_write
+= io
->bytes
;
1007 * Return non-zero if we wish to delay the kernel's attempt to flush
1008 * this buffer to disk.
1011 hammer_io_countdeps(struct buf
*bp
, int n
)
1016 struct bio_ops hammer_bioops
= {
1017 .io_start
= hammer_io_start
,
1018 .io_complete
= hammer_io_complete
,
1019 .io_deallocate
= hammer_io_deallocate
,
1020 .io_fsync
= hammer_io_fsync
,
1021 .io_sync
= hammer_io_sync
,
1022 .io_movedeps
= hammer_io_movedeps
,
1023 .io_countdeps
= hammer_io_countdeps
,
1024 .io_checkread
= hammer_io_checkread
,
1025 .io_checkwrite
= hammer_io_checkwrite
,
1028 /************************************************************************
1030 ************************************************************************
1032 * These functions operate directly on the buffer cache buffer associated
1033 * with a front-end vnode rather then a back-end device vnode.
1037 * Read a buffer associated with a front-end vnode directly from the
1038 * disk media. The bio may be issued asynchronously. If leaf is non-NULL
1039 * we validate the CRC.
1041 * We must check for the presence of a HAMMER buffer to handle the case
1042 * where the reblocker has rewritten the data (which it does via the HAMMER
1043 * buffer system, not via the high-level vnode buffer cache), but not yet
1044 * committed the buffer to the media.
1047 hammer_io_direct_read(hammer_mount_t hmp
, struct bio
*bio
,
1048 hammer_btree_leaf_elm_t leaf
)
1050 hammer_off_t buf_offset
;
1051 hammer_off_t zone2_offset
;
1052 hammer_volume_t volume
;
1058 buf_offset
= bio
->bio_offset
;
1059 KKASSERT((buf_offset
& HAMMER_OFF_ZONE_MASK
) ==
1060 HAMMER_ZONE_LARGE_DATA
);
1063 * The buffer cache may have an aliased buffer (the reblocker can
1064 * write them). If it does we have to sync any dirty data before
1065 * we can build our direct-read. This is a non-critical code path.
1068 hammer_sync_buffers(hmp
, buf_offset
, bp
->b_bufsize
);
1071 * Resolve to a zone-2 offset. The conversion just requires
1072 * munging the top 4 bits but we want to abstract it anyway
1073 * so the blockmap code can verify the zone assignment.
1075 zone2_offset
= hammer_blockmap_lookup(hmp
, buf_offset
, &error
);
1078 KKASSERT((zone2_offset
& HAMMER_OFF_ZONE_MASK
) ==
1079 HAMMER_ZONE_RAW_BUFFER
);
1082 * Resolve volume and raw-offset for 3rd level bio. The
1083 * offset will be specific to the volume.
1085 vol_no
= HAMMER_VOL_DECODE(zone2_offset
);
1086 volume
= hammer_get_volume(hmp
, vol_no
, &error
);
1087 if (error
== 0 && zone2_offset
>= volume
->maxbuf_off
)
1094 nbio
= push_bio(bio
);
1095 nbio
->bio_offset
= volume
->ondisk
->vol_buf_beg
+
1096 (zone2_offset
& HAMMER_OFF_SHORT_MASK
);
1099 * XXX disabled - our CRC check doesn't work if the OS
1100 * does bogus_page replacement on the direct-read.
1102 if (leaf
&& hammer_verify_data
) {
1103 nbio
->bio_done
= hammer_io_direct_read_complete
;
1104 nbio
->bio_caller_info1
.uvalue32
= leaf
->data_crc
;
1107 hammer_stats_disk_read
+= bp
->b_bufsize
;
1108 vn_strategy(volume
->devvp
, nbio
);
1110 hammer_rel_volume(volume
, 0);
1113 kprintf("hammer_direct_read: failed @ %016llx\n",
1114 (long long)zone2_offset
);
1115 bp
->b_error
= error
;
1116 bp
->b_flags
|= B_ERROR
;
1124 * On completion of the BIO this callback must check the data CRC
1125 * and chain to the previous bio.
1129 hammer_io_direct_read_complete(struct bio
*nbio
)
1133 u_int32_t rec_crc
= nbio
->bio_caller_info1
.uvalue32
;
1136 if (crc32(bp
->b_data
, bp
->b_bufsize
) != rec_crc
) {
1137 kprintf("HAMMER: data_crc error @%016llx/%d\n",
1138 nbio
->bio_offset
, bp
->b_bufsize
);
1139 if (hammer_debug_debug
)
1141 bp
->b_flags
|= B_ERROR
;
1144 obio
= pop_bio(nbio
);
1150 * Write a buffer associated with a front-end vnode directly to the
1151 * disk media. The bio may be issued asynchronously.
1153 * The BIO is associated with the specified record and RECF_DIRECT_IO
1154 * is set. The recorded is added to its object.
1157 hammer_io_direct_write(hammer_mount_t hmp
, hammer_record_t record
,
1160 hammer_btree_leaf_elm_t leaf
= &record
->leaf
;
1161 hammer_off_t buf_offset
;
1162 hammer_off_t zone2_offset
;
1163 hammer_volume_t volume
;
1164 hammer_buffer_t buffer
;
1171 buf_offset
= leaf
->data_offset
;
1173 KKASSERT(buf_offset
> HAMMER_ZONE_BTREE
);
1174 KKASSERT(bio
->bio_buf
->b_cmd
== BUF_CMD_WRITE
);
1176 if ((buf_offset
& HAMMER_BUFMASK
) == 0 &&
1177 leaf
->data_len
>= HAMMER_BUFSIZE
) {
1179 * We are using the vnode's bio to write directly to the
1180 * media, any hammer_buffer at the same zone-X offset will
1181 * now have stale data.
1183 zone2_offset
= hammer_blockmap_lookup(hmp
, buf_offset
, &error
);
1184 vol_no
= HAMMER_VOL_DECODE(zone2_offset
);
1185 volume
= hammer_get_volume(hmp
, vol_no
, &error
);
1187 if (error
== 0 && zone2_offset
>= volume
->maxbuf_off
)
1191 KKASSERT((bp
->b_bufsize
& HAMMER_BUFMASK
) == 0);
1193 hammer_del_buffers(hmp, buf_offset,
1194 zone2_offset, bp->b_bufsize);
1198 * Second level bio - cached zone2 offset.
1200 * (We can put our bio_done function in either the
1201 * 2nd or 3rd level).
1203 nbio
= push_bio(bio
);
1204 nbio
->bio_offset
= zone2_offset
;
1205 nbio
->bio_done
= hammer_io_direct_write_complete
;
1206 nbio
->bio_caller_info1
.ptr
= record
;
1207 record
->zone2_offset
= zone2_offset
;
1208 record
->flags
|= HAMMER_RECF_DIRECT_IO
|
1209 HAMMER_RECF_DIRECT_INVAL
;
1212 * Third level bio - raw offset specific to the
1215 zone2_offset
&= HAMMER_OFF_SHORT_MASK
;
1216 nbio
= push_bio(nbio
);
1217 nbio
->bio_offset
= volume
->ondisk
->vol_buf_beg
+
1219 hammer_stats_disk_write
+= bp
->b_bufsize
;
1220 vn_strategy(volume
->devvp
, nbio
);
1221 hammer_io_flush_mark(volume
);
1223 hammer_rel_volume(volume
, 0);
1226 * Must fit in a standard HAMMER buffer. In this case all
1227 * consumers use the HAMMER buffer system and RECF_DIRECT_IO
1228 * does not need to be set-up.
1230 KKASSERT(((buf_offset
^ (buf_offset
+ leaf
->data_len
- 1)) & ~HAMMER_BUFMASK64
) == 0);
1232 ptr
= hammer_bread(hmp
, buf_offset
, &error
, &buffer
);
1235 bp
->b_flags
|= B_AGE
;
1236 hammer_io_modify(&buffer
->io
, 1);
1237 bcopy(bp
->b_data
, ptr
, leaf
->data_len
);
1238 hammer_io_modify_done(&buffer
->io
);
1239 hammer_rel_buffer(buffer
, 0);
1246 * The record is all setup now, add it. Potential conflics
1247 * have already been dealt with.
1249 error
= hammer_mem_add(record
);
1250 KKASSERT(error
== 0);
1253 * Major suckage occured. Also note: The record was never added
1254 * to the tree so we do not have to worry about the backend.
1256 kprintf("hammer_direct_write: failed @ %016llx\n",
1257 (long long)leaf
->data_offset
);
1261 bp
->b_flags
|= B_ERROR
;
1263 record
->flags
|= HAMMER_RECF_DELETED_FE
;
1264 hammer_rel_mem_record(record
);
1270 * On completion of the BIO this callback must disconnect
1271 * it from the hammer_record and chain to the previous bio.
1273 * An I/O error forces the mount to read-only. Data buffers
1274 * are not B_LOCKED like meta-data buffers are, so we have to
1275 * throw the buffer away to prevent the kernel from retrying.
1279 hammer_io_direct_write_complete(struct bio
*nbio
)
1283 hammer_record_t record
= nbio
->bio_caller_info1
.ptr
;
1286 obio
= pop_bio(nbio
);
1287 if (bp
->b_flags
& B_ERROR
) {
1288 hammer_critical_error(record
->ip
->hmp
, record
->ip
,
1290 "while writing bulk data");
1291 bp
->b_flags
|= B_INVAL
;
1295 KKASSERT(record
!= NULL
);
1296 KKASSERT(record
->flags
& HAMMER_RECF_DIRECT_IO
);
1297 if (record
->flags
& HAMMER_RECF_DIRECT_WAIT
) {
1298 record
->flags
&= ~(HAMMER_RECF_DIRECT_IO
|
1299 HAMMER_RECF_DIRECT_WAIT
);
1300 /* record can disappear once DIRECT_IO flag is cleared */
1301 wakeup(&record
->flags
);
1303 record
->flags
&= ~HAMMER_RECF_DIRECT_IO
;
1304 /* record can disappear once DIRECT_IO flag is cleared */
1310 * This is called before a record is either committed to the B-Tree
1311 * or destroyed, to resolve any associated direct-IO.
1313 * (1) We must wait for any direct-IO related to the record to complete.
1315 * (2) We must remove any buffer cache aliases for data accessed via
1316 * leaf->data_offset or zone2_offset so non-direct-IO consumers
1317 * (the mirroring and reblocking code) do not see stale data.
1320 hammer_io_direct_wait(hammer_record_t record
)
1323 * Wait for I/O to complete
1325 if (record
->flags
& HAMMER_RECF_DIRECT_IO
) {
1327 while (record
->flags
& HAMMER_RECF_DIRECT_IO
) {
1328 record
->flags
|= HAMMER_RECF_DIRECT_WAIT
;
1329 tsleep(&record
->flags
, 0, "hmdiow", 0);
1335 * Invalidate any related buffer cache aliases associated with the
1336 * backing device. This is needed because the buffer cache buffer
1337 * for file data is associated with the file vnode, not the backing
1340 * XXX I do not think this case can occur any more now that
1341 * reservations ensure that all such buffers are removed before
1342 * an area can be reused.
1344 if (record
->flags
& HAMMER_RECF_DIRECT_INVAL
) {
1345 KKASSERT(record
->leaf
.data_offset
);
1346 hammer_del_buffers(record
->ip
->hmp
, record
->leaf
.data_offset
,
1347 record
->zone2_offset
, record
->leaf
.data_len
,
1349 record
->flags
&= ~HAMMER_RECF_DIRECT_INVAL
;
1354 * This is called to remove the second-level cached zone-2 offset from
1355 * frontend buffer cache buffers, now stale due to a data relocation.
1356 * These offsets are generated by cluster_read() via VOP_BMAP, or directly
1357 * by hammer_vop_strategy_read().
1359 * This is rather nasty because here we have something like the reblocker
1360 * scanning the raw B-Tree with no held references on anything, really,
1361 * other then a shared lock on the B-Tree node, and we have to access the
1362 * frontend's buffer cache to check for and clean out the association.
1363 * Specifically, if the reblocker is moving data on the disk, these cached
1364 * offsets will become invalid.
1366 * Only data record types associated with the large-data zone are subject
1367 * to direct-io and need to be checked.
1371 hammer_io_direct_uncache(hammer_mount_t hmp
, hammer_btree_leaf_elm_t leaf
)
1373 struct hammer_inode_info iinfo
;
1376 if (leaf
->base
.rec_type
!= HAMMER_RECTYPE_DATA
)
1378 zone
= HAMMER_ZONE_DECODE(leaf
->data_offset
);
1379 if (zone
!= HAMMER_ZONE_LARGE_DATA_INDEX
)
1381 iinfo
.obj_id
= leaf
->base
.obj_id
;
1382 iinfo
.obj_asof
= 0; /* unused */
1383 iinfo
.obj_localization
= leaf
->base
.localization
&
1384 HAMMER_LOCALIZE_PSEUDOFS_MASK
;
1385 iinfo
.u
.leaf
= leaf
;
1386 hammer_scan_inode_snapshots(hmp
, &iinfo
,
1387 hammer_io_direct_uncache_callback
,
1392 hammer_io_direct_uncache_callback(hammer_inode_t ip
, void *data
)
1394 hammer_inode_info_t iinfo
= data
;
1395 hammer_off_t data_offset
;
1396 hammer_off_t file_offset
;
1403 data_offset
= iinfo
->u
.leaf
->data_offset
;
1404 file_offset
= iinfo
->u
.leaf
->base
.key
- iinfo
->u
.leaf
->data_len
;
1405 blksize
= iinfo
->u
.leaf
->data_len
;
1406 KKASSERT((blksize
& HAMMER_BUFMASK
) == 0);
1408 hammer_ref(&ip
->lock
);
1409 if (hammer_get_vnode(ip
, &vp
) == 0) {
1410 if ((bp
= findblk(ip
->vp
, file_offset
, FINDBLK_TEST
)) != NULL
&&
1411 bp
->b_bio2
.bio_offset
!= NOOFFSET
) {
1412 bp
= getblk(ip
->vp
, file_offset
, blksize
, 0, 0);
1413 bp
->b_bio2
.bio_offset
= NOOFFSET
;
1418 hammer_rel_inode(ip
, 0);
1424 * This function is called when writes may have occured on the volume,
1425 * indicating that the device may be holding cached writes.
1428 hammer_io_flush_mark(hammer_volume_t volume
)
1430 volume
->vol_flags
|= HAMMER_VOLF_NEEDFLUSH
;
1434 * This function ensures that the device has flushed any cached writes out.
1437 hammer_io_flush_sync(hammer_mount_t hmp
)
1439 hammer_volume_t volume
;
1440 struct buf
*bp_base
= NULL
;
1443 RB_FOREACH(volume
, hammer_vol_rb_tree
, &hmp
->rb_vols_root
) {
1444 if (volume
->vol_flags
& HAMMER_VOLF_NEEDFLUSH
) {
1445 volume
->vol_flags
&= ~HAMMER_VOLF_NEEDFLUSH
;
1447 bp
->b_bio1
.bio_offset
= 0;
1450 bp
->b_cmd
= BUF_CMD_FLUSH
;
1451 bp
->b_bio1
.bio_caller_info1
.cluster_head
= bp_base
;
1452 bp
->b_bio1
.bio_done
= biodone_sync
;
1453 bp
->b_bio1
.bio_flags
|= BIO_SYNC
;
1455 vn_strategy(volume
->devvp
, &bp
->b_bio1
);
1458 while ((bp
= bp_base
) != NULL
) {
1459 bp_base
= bp
->b_bio1
.bio_caller_info1
.cluster_head
;
1460 biowait(&bp
->b_bio1
, "hmrFLS");