2 * Copyright (c) 2011-2013 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@dragonflybsd.org>
6 * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in
16 * the documentation and/or other materials provided with the
18 * 3. Neither the name of The DragonFly Project nor the names of its
19 * contributors may be used to endorse or promote products derived
20 * from this software without specific, prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
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30 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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32 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 #include <sys/cdefs.h>
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/types.h>
46 * Recursively flush the specified chain. The chain is locked and
47 * referenced by the caller and will remain so on return. The chain
48 * will remain referenced throughout but can temporarily lose its
49 * lock during the recursion to avoid unnecessarily stalling user
52 struct hammer2_flush_info {
54 hammer2_chain_t *parent;
55 hammer2_trans_t *trans;
58 struct flush_deferral_list flush_list;
59 hammer2_tid_t sync_tid; /* flush synchronization point */
60 hammer2_tid_t mirror_tid; /* collect mirror TID updates */
63 typedef struct hammer2_flush_info hammer2_flush_info_t;
65 static void hammer2_chain_flush_core(hammer2_flush_info_t *info,
66 hammer2_chain_t *chain);
67 static int hammer2_chain_flush_scan1(hammer2_chain_t *child, void *data);
68 static int hammer2_chain_flush_scan2(hammer2_chain_t *child, void *data);
71 * Transaction support functions for writing to the filesystem.
73 * Initializing a new transaction allocates a transaction ID. We
74 * don't bother marking the volume header MODIFIED. Instead, the volume
75 * will be synchronized at a later time as part of a larger flush sequence.
77 * Non-flush transactions can typically run concurrently. However if
78 * there are non-flush transaction both before AND after a flush trans,
79 * the transactions after stall until the ones before finish.
81 * Non-flush transactions occuring after a flush pointer can run concurrently
82 * with that flush. They only have to wait for transactions prior to the
83 * flush trans to complete before they unstall.
85 * WARNING! Modifications to the root volume cannot dup the root volume
86 * header to handle synchronization points, so alloc_tid can
87 * wind up (harmlessly) more advanced on flush.
89 * WARNING! Operations which might call inode_duplicate()/chain_duplicate()
90 * depend heavily on having a unique sync_tid to avoid duplication
91 * collisions (which key off of delete_tid).
94 hammer2_trans_init(hammer2_mount_t *hmp, hammer2_trans_t *trans, int flags)
96 hammer2_trans_t *scan;
98 bzero(trans, sizeof(*trans));
101 hammer2_voldata_lock(hmp);
102 trans->sync_tid = hmp->voldata.alloc_tid++;
103 trans->flags = flags;
104 trans->td = curthread;
105 TAILQ_INSERT_TAIL(&hmp->transq, trans, entry);
107 if (flags & HAMMER2_TRANS_ISFLUSH) {
109 * If we are a flush we have to wait for all transactions
110 * prior to our flush synchronization point to complete
111 * before we can start our flush.
114 if (hmp->curflush == NULL) {
115 hmp->curflush = trans;
116 hmp->flush_tid = trans->sync_tid;
118 while (TAILQ_FIRST(&hmp->transq) != trans) {
119 lksleep(&trans->sync_tid, &hmp->voldatalk,
124 * Once we become the running flush we can wakeup anyone
128 while ((scan = TAILQ_NEXT(scan, entry)) != NULL) {
129 if (scan->flags & HAMMER2_TRANS_ISFLUSH)
131 if (scan->blocked == 0)
134 wakeup(&scan->blocked);
138 * If we are not a flush but our sync_tid is after a
139 * stalled flush, we have to wait until that flush unstalls
140 * (that is, all transactions prior to that flush complete),
141 * but then we can run concurrently with that flush.
143 * (flushcnt check only good as pre-condition, otherwise it
144 * may represent elements queued after us after we block).
146 if (hmp->flushcnt > 1 ||
148 TAILQ_FIRST(&hmp->transq) != hmp->curflush)) {
150 while (trans->blocked) {
151 lksleep(&trans->blocked, &hmp->voldatalk,
156 hammer2_voldata_unlock(hmp, 0);
160 hammer2_trans_done(hammer2_trans_t *trans)
162 hammer2_mount_t *hmp = trans->hmp;
163 hammer2_trans_t *scan;
165 hammer2_voldata_lock(hmp);
166 TAILQ_REMOVE(&hmp->transq, trans, entry);
167 if (trans->flags & HAMMER2_TRANS_ISFLUSH) {
169 * If we were a flush we have to adjust curflush to the
172 * flush_tid is used to partition copy-on-write operations
173 * (mostly duplicate-on-modify ops), which is what allows
174 * us to execute a flush concurrent with modifying operations
179 TAILQ_FOREACH(scan, &hmp->transq, entry) {
180 if (scan->flags & HAMMER2_TRANS_ISFLUSH)
184 hmp->curflush = scan;
185 hmp->flush_tid = scan->sync_tid;
188 * Theoretically we don't have to clear flush_tid
189 * here since the flush will have synchronized
190 * all operations <= flush_tid already. But for
193 hmp->curflush = NULL;
198 * If we are not a flush but a flush is now at the head
199 * of the queue and we were previously blocking it,
200 * we can now unblock it.
203 (scan = TAILQ_FIRST(&hmp->transq)) != NULL &&
204 trans->sync_tid < scan->sync_tid &&
205 (scan->flags & HAMMER2_TRANS_ISFLUSH)) {
206 wakeup(&scan->sync_tid);
209 hammer2_voldata_unlock(hmp, 0);
215 * Flush the chain and all modified sub-chains through the specified
216 * synchronization point (sync_tid), propagating parent chain modifications
217 * and mirror_tid updates back up as needed. Since we are recursing downward
218 * we do not have to deal with the complexities of multi-homed chains (chains
219 * with multiple parents).
221 * Caller must have interlocked against any non-flush-related modifying
222 * operations in progress whos modify_tid values are less than or equal
223 * to the passed sync_tid.
225 * Caller must have already vetted synchronization points to ensure they
226 * are properly flushed. Only snapshots and cluster flushes can create
227 * these sorts of synchronization points.
229 * SUBMODIFIED is not cleared if modified elements with higher modify_tid
230 * values (thus not flushed) are still present after the flush.
232 * If a chain is unable to completely flush we have to be sure that
233 * SUBMODIFIED remains set up the parent chain, and that MOVED is not
234 * cleared or our desynchronized bref will not properly update in the
235 * parent. The parent's indirect block is copied-on-write and adjusted
236 * as needed so it no longer needs to be placemarked by the subchains,
237 * allowing the sub-chains to be cleaned out.
239 * This routine can be called from several places but the most important
240 * is from the hammer2_vop_reclaim() function. We want to try to completely
241 * clean out the inode structure to prevent disconnected inodes from
242 * building up and blowing out the kmalloc pool. However, it is not actually
243 * necessary to flush reclaimed inodes to maintain HAMMER2's crash recovery
246 * chain is locked on call and will remain locked on return. If a flush
247 * occured, the chain's MOVED bit will be set indicating that its parent
248 * (which is not part of the flush) should be updated.
251 hammer2_chain_flush(hammer2_trans_t *trans, hammer2_chain_t *chain)
253 hammer2_chain_t *scan;
254 hammer2_chain_core_t *core;
255 hammer2_flush_info_t info;
258 * Execute the recursive flush and handle deferrals.
260 * Chains can be ridiculously long (thousands deep), so to
261 * avoid blowing out the kernel stack the recursive flush has a
262 * depth limit. Elements at the limit are placed on a list
263 * for re-execution after the stack has been popped.
265 bzero(&info, sizeof(info));
266 TAILQ_INIT(&info.flush_list);
267 info.hmp = trans->hmp;
269 info.sync_tid = trans->sync_tid;
276 * Unwind deep recursions which had been deferred. This
277 * can leave MOVED set for these chains, which will be
278 * handled when we [re]flush chain after the unwind.
280 while ((scan = TAILQ_FIRST(&info.flush_list)) != NULL) {
281 KKASSERT(scan->flags & HAMMER2_CHAIN_DEFERRED);
282 TAILQ_REMOVE(&info.flush_list, scan, flush_node);
283 atomic_clear_int(&scan->flags, HAMMER2_CHAIN_DEFERRED);
286 * Now that we've popped back up we can do a secondary
287 * recursion on the deferred elements.
289 if (hammer2_debug & 0x0040)
290 kprintf("defered flush %p\n", scan);
291 hammer2_chain_lock(scan, HAMMER2_RESOLVE_MAYBE);
292 hammer2_chain_flush(trans, scan);
293 hammer2_chain_unlock(scan);
294 hammer2_chain_drop(scan); /* ref from deferral */
298 * Flush pass1 on root. SUBMODIFIED can remain set after
299 * this call for numerous reasons, including write failures,
300 * but most likely due to only a partial flush being
301 * requested or the chain element belongs to the wrong
302 * synchronization point.
304 info.diddeferral = 0;
305 hammer2_chain_flush_core(&info, chain);
307 kprintf("flush_core_done parent=<base> chain=%p.%d %08x\n",
308 chain, chain->bref.type, chain->flags);
312 * Only loop if deep recursions have been deferred.
314 if (TAILQ_EMPTY(&info.flush_list))
319 * SUBMODIFIED can be temporarily cleared and then re-set, which
320 * can prevent concurrent setsubmods from reaching all the way to
321 * the root. If after the flush we find the node is still in need
322 * of flushing (though possibly due to modifications made outside
323 * the requested synchronization zone), we must call setsubmod again
326 if (chain->flags & (HAMMER2_CHAIN_MOVED |
327 HAMMER2_CHAIN_DELETED |
328 HAMMER2_CHAIN_MODIFIED |
329 HAMMER2_CHAIN_SUBMODIFIED)) {
330 hammer2_chain_setsubmod(trans, chain);
335 * This is the core of the chain flushing code. The chain is locked by the
336 * caller and remains locked on return. This function is keyed off of
337 * the SUBMODIFIED bit but must make fine-grained choices based on the
338 * synchronization point we are flushing to.
340 * If the flush accomplished any work chain will be flagged MOVED
341 * indicating a copy-on-write propagation back up is required.
342 * Deep sub-nodes may also have been entered onto the deferral list.
343 * MOVED is never set on the volume root.
345 * NOTE: modify_tid is different from MODIFIED. modify_tid is updated
346 * only when a chain is specifically modified, and not updated
347 * for copy-on-write propagations. MODIFIED is set on any modification
348 * including copy-on-write propagations.
351 hammer2_chain_flush_core(hammer2_flush_info_t *info, hammer2_chain_t *chain)
353 hammer2_mount_t *hmp;
354 hammer2_blockref_t *bref;
356 hammer2_tid_t saved_sync;
357 hammer2_trans_t *trans = info->trans;
358 hammer2_chain_core_t *core;
371 kprintf("flush_core %p->%p.%d %08x (%s)\n",
372 info->parent, chain, chain->bref.type,
374 ((chain->bref.type == HAMMER2_BREF_TYPE_INODE) ?
375 chain->data->ipdata.filename : "?"));
377 kprintf("flush_core NULL->%p.%d %08x (%s)\n",
378 chain, chain->bref.type,
380 ((chain->bref.type == HAMMER2_BREF_TYPE_INODE) ?
381 chain->data->ipdata.filename : "?"));
384 * Ignore chains modified beyond the current flush point. These
385 * will be treated as if they did not exist.
387 if (chain->modify_tid > info->sync_tid)
391 * Deleted chains which have not been destroyed must be retained,
392 * and we probably have to recurse to clean-up any sub-trees.
393 * However, restricted flushes can stop processing here because
394 * the chain cleanup will be handled by a later normal flush.
396 * The MODIFIED bit can likely be cleared in this situation and we
397 * will do so later on in this procedure.
399 if (chain->delete_tid <= info->sync_tid) {
400 if (trans->flags & HAMMER2_TRANS_RESTRICTED)
404 saved_sync = info->sync_tid;
408 * If SUBMODIFIED is set we recurse the flush and adjust the
409 * blockrefs accordingly.
411 * NOTE: Looping on SUBMODIFIED can prevent a flush from ever
412 * finishing in the face of filesystem activity.
414 if (chain->flags & HAMMER2_CHAIN_SUBMODIFIED) {
415 hammer2_chain_t *saved_parent;
416 hammer2_tid_t saved_mirror;
419 * Clear SUBMODIFIED to catch races. Note that any child
420 * with MODIFIED, DELETED, or MOVED set during Scan2, after
421 * it processes the child, will cause SUBMODIFIED to be
423 * child has to be flushed SUBMODIFIED will wind up being
424 * set again (for next time), but this does not stop us from
425 * synchronizing block updates which occurred.
427 * We don't want to set our chain to MODIFIED gratuitously.
429 * We need an extra ref on chain because we are going to
430 * release its lock temporarily in our child loop.
432 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_SUBMODIFIED);
433 hammer2_chain_ref(chain);
436 * Run two passes. The first pass handles MODIFIED and
437 * SUBMODIFIED chains and recurses while the second pass
438 * handles MOVED chains on the way back up.
440 * If the stack gets too deep we defer scan1, but must
441 * be sure to still run scan2 if on the next loop the
442 * deferred chain has been flushed and now needs MOVED
443 * handling on the way back up.
445 * Scan1 is recursive.
447 * NOTE: The act of handling a modified/submodified chain can
448 * cause the MOVED Flag to be set. It can also be set
449 * via hammer2_chain_delete() and in other situations.
451 * NOTE: RB_SCAN() must be used instead of RB_FOREACH()
452 * because children can be physically removed during
455 saved_parent = info->parent;
456 saved_mirror = info->mirror_tid;
457 info->parent = chain;
458 info->mirror_tid = chain->bref.mirror_tid;
460 if (info->depth == HAMMER2_FLUSH_DEPTH_LIMIT) {
461 if ((chain->flags & HAMMER2_CHAIN_DEFERRED) == 0) {
462 hammer2_chain_ref(chain);
463 TAILQ_INSERT_TAIL(&info->flush_list,
465 atomic_set_int(&chain->flags,
466 HAMMER2_CHAIN_DEFERRED);
470 info->diddeferral = 0;
471 spin_lock(&core->cst.spin);
472 RB_SCAN(hammer2_chain_tree, &chain->core->rbtree,
473 NULL, hammer2_chain_flush_scan1, info);
474 spin_unlock(&core->cst.spin);
475 diddeferral += info->diddeferral;
479 * Handle successfully flushed children who are in the MOVED
480 * state on the way back up the recursion. This can have
481 * the side-effect of clearing MOVED.
483 * We execute this even if there were deferrals to try to
484 * keep the chain topology cleaner.
486 * Scan2 is non-recursive.
489 atomic_set_int(&chain->flags,
490 HAMMER2_CHAIN_SUBMODIFIED);
493 kprintf("scan2_start parent %p %08x\n", chain, chain->flags);
495 spin_lock(&core->cst.spin);
496 RB_SCAN(hammer2_chain_tree, &core->rbtree,
497 NULL, hammer2_chain_flush_scan2, info);
498 spin_unlock(&core->cst.spin);
500 kprintf("scan2_stop parent %p %08x\n", chain, chain->flags);
503 chain->bref.mirror_tid = info->mirror_tid;
504 info->mirror_tid = saved_mirror;
505 info->parent = saved_parent;
506 hammer2_chain_drop(chain);
510 * Restore sync_tid in case it was restricted by a delete/duplicate.
512 info->sync_tid = saved_sync;
515 * Rollup diddeferral for caller. Note direct assignment, not +=.
517 info->diddeferral = diddeferral;
520 * Do not flush chain if there were any deferrals. It will be
521 * retried later after the deferrals are independently handled.
524 if (hammer2_debug & 0x0008) {
525 kprintf("%*.*s} %p/%d %04x (deferred)",
526 info->depth, info->depth, "",
527 chain, chain->refs, chain->flags);
533 * If we encounter a deleted chain within our flush we can clear
534 * the MODIFIED bit and avoid flushing it whether it has been
537 if (chain->delete_tid <= info->sync_tid) {
538 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
540 chain->bp->b_flags |= B_INVAL|B_RELBUF;
541 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
542 hammer2_chain_drop(chain);
547 if ((chain->flags & HAMMER2_CHAIN_DESTROYED) &&
548 (chain->flags & HAMMER2_CHAIN_DELETED) &&
549 (trans->flags & HAMMER2_TRANS_RESTRICTED) == 0) {
551 * Throw-away the MODIFIED flag
553 if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
555 chain->bp->b_flags |= B_INVAL|B_RELBUF;
556 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
557 hammer2_chain_drop(chain);
564 * A degenerate flush might not have flushed anything and thus not
565 * processed modified blocks on the way back up. Detect the case.
567 * Note that MOVED can be set without MODIFIED being set due to
568 * a deletion, in which case it is handled by Scan2 later on.
570 * Both bits can be set along with DELETED due to a deletion if
571 * modified data within the synchronization zone and the chain
572 * was then deleted beyond the zone, in which case we still have
573 * to flush for synchronization point consistency. Otherwise though
574 * DELETED and MODIFIED are treated as separate flags.
576 if ((chain->flags & HAMMER2_CHAIN_MODIFIED) == 0)
582 * A DESTROYED node that reaches this point must be flushed for
583 * synchronization point consistency.
587 * Update mirror_tid, clear MODIFIED, and set MOVED.
589 * The caller will update the parent's reference to this chain
590 * by testing MOVED as long as the modification was in-bounds.
592 * MOVED is never set on the volume root as there is no parent
595 if (chain->bref.mirror_tid < info->sync_tid)
596 chain->bref.mirror_tid = info->sync_tid;
597 wasmodified = (chain->flags & HAMMER2_CHAIN_MODIFIED) != 0;
598 atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
599 if (chain == &hmp->vchain)
600 kprintf("(FLUSHED VOLUME HEADER)\n");
602 if ((chain->flags & HAMMER2_CHAIN_MOVED) ||
603 chain == &hmp->vchain) {
605 * Drop the ref from the MODIFIED bit we cleared.
608 hammer2_chain_drop(chain);
611 * If we were MODIFIED we inherit the ref from clearing
612 * that bit, otherwise we need another ref.
614 if (wasmodified == 0)
615 hammer2_chain_ref(chain);
616 atomic_set_int(&chain->flags, HAMMER2_CHAIN_MOVED);
620 * If this is part of a recursive flush we can go ahead and write
621 * out the buffer cache buffer and pass a new bref back up the chain
624 * Volume headers are NOT flushed here as they require special
627 switch(chain->bref.type) {
628 case HAMMER2_BREF_TYPE_VOLUME:
630 * The volume header is flushed manually by the syncer, not
631 * here. All we do is adjust the crc's.
633 KKASSERT(chain->data != NULL);
634 KKASSERT(chain->bp == NULL);
635 kprintf("volume header mirror_tid %jd\n",
636 hmp->voldata.mirror_tid);
638 hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT1]=
640 (char *)&hmp->voldata +
641 HAMMER2_VOLUME_ICRC1_OFF,
642 HAMMER2_VOLUME_ICRC1_SIZE);
643 hmp->voldata.icrc_sects[HAMMER2_VOL_ICRC_SECT0]=
645 (char *)&hmp->voldata +
646 HAMMER2_VOLUME_ICRC0_OFF,
647 HAMMER2_VOLUME_ICRC0_SIZE);
648 hmp->voldata.icrc_volheader =
650 (char *)&hmp->voldata +
651 HAMMER2_VOLUME_ICRCVH_OFF,
652 HAMMER2_VOLUME_ICRCVH_SIZE);
653 hmp->volsync = hmp->voldata;
654 atomic_set_int(&chain->flags, HAMMER2_CHAIN_VOLUMESYNC);
656 case HAMMER2_BREF_TYPE_DATA:
658 * Data elements have already been flushed via the logical
659 * file buffer cache. Their hash was set in the bref by
660 * the vop_write code.
662 * Make sure any device buffer(s) have been flushed out here.
663 * (there aren't usually any to flush).
665 bbytes = chain->bytes;
666 pbase = chain->bref.data_off & ~(hammer2_off_t)(bbytes - 1);
667 boff = chain->bref.data_off & HAMMER2_OFF_MASK & (bbytes - 1);
669 bp = getblk(hmp->devvp, pbase, bbytes, GETBLK_NOWAIT, 0);
671 if ((bp->b_flags & (B_CACHE | B_DIRTY)) ==
672 (B_CACHE | B_DIRTY)) {
675 bp->b_flags |= B_RELBUF;
680 case HAMMER2_BREF_TYPE_INDIRECT:
682 * Indirect blocks may be in an INITIAL state. Use the
683 * chain_lock() call to ensure that the buffer has been
684 * instantiated (even though it is already locked the buffer
685 * might not have been instantiated).
687 * Only write the buffer out if it is dirty, it is possible
688 * the operating system had already written out the buffer.
690 hammer2_chain_lock(chain, HAMMER2_RESOLVE_ALWAYS);
691 KKASSERT(chain->bp != NULL);
694 if ((chain->flags & HAMMER2_CHAIN_DIRTYBP) ||
695 (bp->b_flags & B_DIRTY)) {
702 hammer2_chain_unlock(chain);
706 * Embedded elements have to be flushed out.
708 KKASSERT(chain->data != NULL);
709 KKASSERT(chain->bp == NULL);
712 KKASSERT((bref->data_off & HAMMER2_OFF_MASK) != 0);
713 KKASSERT(HAMMER2_DEC_CHECK(chain->bref.methods) ==
714 HAMMER2_CHECK_ISCSI32);
716 if (chain->bp == NULL) {
718 * The data is embedded, we have to acquire the
719 * buffer cache buffer and copy the data into it.
721 if ((bbytes = chain->bytes) < HAMMER2_MINIOSIZE)
722 bbytes = HAMMER2_MINIOSIZE;
723 pbase = bref->data_off & ~(hammer2_off_t)(bbytes - 1);
724 boff = bref->data_off & HAMMER2_OFF_MASK & (bbytes - 1);
727 * The getblk() optimization can only be used if the
728 * physical block size matches the request.
730 if (chain->bytes == bbytes) {
731 bp = getblk(hmp->devvp, pbase, bbytes, 0, 0);
734 error = bread(hmp->devvp, pbase, bbytes, &bp);
735 KKASSERT(error == 0);
737 bdata = (char *)bp->b_data + boff;
740 * Copy the data to the buffer, mark the buffer
741 * dirty, and convert the chain to unmodified.
743 bcopy(chain->data, bdata, chain->bytes);
744 bp->b_flags |= B_CLUSTEROK;
747 chain->bref.check.iscsi32.value =
748 hammer2_icrc32(chain->data, chain->bytes);
749 if (chain->bref.type == HAMMER2_BREF_TYPE_INODE)
750 ++hammer2_iod_meta_write;
752 ++hammer2_iod_indr_write;
754 chain->bref.check.iscsi32.value =
755 hammer2_icrc32(chain->data, chain->bytes);
761 * Flush helper scan1 (recursive)
763 * Flushes the children of the caller's chain (parent) and updates
764 * the blockref, restricted by sync_tid.
766 * Ripouts during the loop should not cause any problems. Because we are
767 * flushing to a synchronization point, modification races will occur after
768 * sync_tid and do not have to be flushed anyway.
770 * It is also ok if the parent is chain_duplicate()'d while unlocked because
771 * the delete/duplication will install a delete_tid that is still larger than
772 * our current sync_tid.
775 hammer2_chain_flush_scan1(hammer2_chain_t *child, void *data)
777 hammer2_flush_info_t *info = data;
778 hammer2_trans_t *trans = info->trans;
779 hammer2_chain_t *parent = info->parent;
780 /*hammer2_mount_t *hmp = info->hmp;*/
784 * We should only need to recurse if SUBMODIFIED is set, but as
785 * a safety also recurse if MODIFIED is also set. Return early
786 * if neither bit is set.
788 if ((child->flags & (HAMMER2_CHAIN_MODIFIED |
789 HAMMER2_CHAIN_SUBMODIFIED)) == 0) {
792 if (child->modify_tid > trans->sync_tid) {
796 hammer2_chain_ref(child);
797 spin_unlock(&parent->core->cst.spin);
800 * The caller has added a ref to the parent so we can temporarily
801 * unlock it in order to lock the child. Re-check the flags before
804 hammer2_chain_unlock(parent);
805 hammer2_chain_lock(child, HAMMER2_RESOLVE_MAYBE);
807 if ((child->flags & (HAMMER2_CHAIN_MODIFIED |
808 HAMMER2_CHAIN_SUBMODIFIED)) == 0) {
809 hammer2_chain_unlock(child);
810 hammer2_chain_drop(child);
811 hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
812 spin_lock(&parent->core->cst.spin);
815 if (child->modify_tid > trans->sync_tid) {
816 hammer2_chain_unlock(child);
817 hammer2_chain_drop(child);
818 hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
819 spin_lock(&parent->core->cst.spin);
824 * The DESTROYED flag can only be initially set on an unreferenced
825 * deleted inode and will propagate downward via the mechanic below.
826 * Such inode chains have been deleted for good and should no longer
827 * be subject to delete/duplication.
829 * This optimization allows the inode reclaim (destroy unlinked file
830 * on vnode reclamation after last close) to be flagged by just
831 * setting HAMMER2_CHAIN_DESTROYED at the top level and then will
832 * cause the chains to be terminated and related buffers to be
833 * invalidated and not flushed out.
835 * We have to be careful not to propagate the DESTROYED flag if
836 * the destruction occurred after our flush sync_tid.
838 if ((parent->flags & HAMMER2_CHAIN_DESTROYED) &&
839 (child->flags & HAMMER2_CHAIN_DELETED) &&
840 (child->flags & HAMMER2_CHAIN_DESTROYED) == 0) {
841 atomic_set_int(&child->flags, HAMMER2_CHAIN_DESTROYED |
842 HAMMER2_CHAIN_SUBMODIFIED);
846 * Recurse and collect deferral data.
848 diddeferral = info->diddeferral;
850 hammer2_chain_flush_core(info, child);
852 kprintf("flush_core_done parent=%p flags=%08x child=%p.%d %08x\n",
853 parent, parent->flags, child, child->bref.type, child->flags);
856 info->diddeferral += diddeferral;
858 hammer2_chain_unlock(child);
859 hammer2_chain_drop(child);
861 hammer2_chain_lock(parent, HAMMER2_RESOLVE_MAYBE);
863 spin_lock(&parent->core->cst.spin);
868 * Flush helper scan2 (non-recursive)
870 * This pass on a chain's children propagates any MOVED or DELETED
871 * elements back up the chain towards the root after those elements have
872 * been fully flushed. Unlike scan1, this function is NOT recursive and
873 * the parent remains locked across the entire scan.
875 * NOTE! We must re-set SUBMODIFIED on the parent(s) as appropriate, and
876 * due to the above conditions it is possible to do this and still
877 * have some children flagged MOVED depending on the synchronization.
879 * NOTE! A deletion is a visbility issue, there can still be referenced to
880 * deleted elements (for example, to an unlinked file which is still
881 * open), and there can also be multiple chains pointing to the same
882 * bref where some are deleted and some are not (for example due to
883 * a rename). So a chain marked for deletion is basically considered
884 * to be live until it is explicitly destroyed or until its ref-count
885 * reaches zero (also implying that MOVED and MODIFIED are clear).
888 hammer2_chain_flush_scan2(hammer2_chain_t *child, void *data)
890 hammer2_flush_info_t *info = data;
891 hammer2_chain_t *parent = info->parent;
892 hammer2_chain_core_t *above = child->above;
893 hammer2_mount_t *hmp = info->hmp;
894 hammer2_trans_t *trans = info->trans;
895 hammer2_blockref_t *base;
899 * Inodes with stale children that have been converted to DIRECTDATA
900 * mode (file extension or hardlink conversion typically) need to
901 * skipped right now before we start messing with a non-existant
904 if (parent->bref.type == HAMMER2_BREF_TYPE_INODE &&
905 (parent->data->ipdata.op_flags & HAMMER2_OPFLAG_DIRECTDATA)) {
913 * Ignore children created after our flush point, treating them as
914 * if they did not exist). These children will not cause the parent
917 * When we encounter such children and the parent chain has not been
918 * deleted, delete/duplicated, or delete/duplicated-for-move, then
919 * the parent may be used to funnel through several flush points.
920 * We must re-set the SUBMODIFIED flag in the parent to ensure that
921 * those flushes have visbility. A simple test of delete_tid suffices
922 * to determine if the parent spans beyond our current flush.
924 if (child->modify_tid > trans->sync_tid) {
928 if (parent->delete_tid > trans->sync_tid) {
929 atomic_set_int(&parent->flags,
930 HAMMER2_CHAIN_SUBMODIFIED);
936 * Ignore children which have not changed. The parent's block table
937 * is already correct.
939 if ((child->flags & HAMMER2_CHAIN_MOVED) == 0) {
947 hammer2_chain_ref(child);
948 spin_unlock(&above->cst.spin);
951 * The MOVED bit implies an additional reference which prevents
952 * the child from being destroyed out from under our operation
953 * so we can lock the child safely without worrying about it
954 * getting ripped up (?).
956 * We can only update parents where child->parent matches. The
957 * child->parent link will migrate along the chain but the flush
958 * order must be enforced absolutely. Parent reflushed after the
959 * child has passed them by should skip due to the modify_tid test.
961 hammer2_chain_lock(child, HAMMER2_RESOLVE_NEVER);
964 * The parent's blockref to the child must be deleted or updated.
966 * This point is not reached on successful DESTROYED optimizations
967 * but can be reached on recursive deletions and restricted flushes.
969 * Because flushes are ordered we do not have to make a
970 * modify/duplicate of indirect blocks. That is, the flush
971 * code does not have to kmalloc or duplicate anything. We
972 * can adjust the indirect block table in-place and reuse the
973 * chain. It IS possible that the chain has already been duplicated
974 * or may wind up being duplicated on-the-fly by modifying code
975 * on the frontend. We simply use the original and ignore such
976 * chains. However, it does mean we can't clear the MOVED bit.
978 * XXX recursive deletions not optimized.
980 hammer2_chain_modify(trans, &parent,
981 HAMMER2_MODIFY_NO_MODIFY_TID |
982 HAMMER2_MODIFY_ASSERTNOCOPY);
984 switch(parent->bref.type) {
985 case HAMMER2_BREF_TYPE_INODE:
987 * XXX Should assert that OPFLAG_DIRECTDATA is 0 once we
988 * properly duplicate the inode headers and do proper flush
989 * range checks (all the children should be beyond the flush
990 * point). For now just don't sync the non-applicable
993 * XXX Can also occur due to hardlink consolidation. We
994 * set OPFLAG_DIRECTDATA to prevent the indirect and data
995 * blocks from syncing ot the hardlink pointer.
998 KKASSERT((parent->data->ipdata.op_flags &
999 HAMMER2_OPFLAG_DIRECTDATA) == 0);
1001 if (parent->data->ipdata.op_flags &
1002 HAMMER2_OPFLAG_DIRECTDATA) {
1005 base = &parent->data->ipdata.u.blockset.blockref[0];
1006 count = HAMMER2_SET_COUNT;
1009 case HAMMER2_BREF_TYPE_INDIRECT:
1011 base = &parent->data->npdata.blockref[0];
1014 KKASSERT(child->flags & HAMMER2_CHAIN_DELETED);
1016 count = parent->bytes / sizeof(hammer2_blockref_t);
1018 case HAMMER2_BREF_TYPE_VOLUME:
1019 base = &hmp->voldata.sroot_blockset.blockref[0];
1020 count = HAMMER2_SET_COUNT;
1025 panic("hammer2_chain_get: "
1026 "unrecognized blockref type: %d",
1031 * Update the parent's blockref table and propagate mirror_tid.
1033 * NOTE! Children with modify_tid's beyond our flush point are
1034 * considered to not exist for the purposes of updating the
1035 * parent's blockref array.
1037 * NOTE! Updates to a parent's blockref table do not adjust the
1038 * parent's bref.modify_tid, only its bref.mirror_tid.
1040 KKASSERT(child->index >= 0);
1041 if (child->delete_tid <= trans->sync_tid) {
1043 KKASSERT(child->index < count);
1044 bzero(&base[child->index], sizeof(child->bref));
1045 if (info->mirror_tid < child->delete_tid)
1046 info->mirror_tid = child->delete_tid;
1050 KKASSERT(child->index < count);
1051 base[child->index] = child->bref;
1052 if (info->mirror_tid < child->modify_tid)
1053 info->mirror_tid = child->modify_tid;
1057 if (info->mirror_tid < child->bref.mirror_tid) {
1058 info->mirror_tid = child->bref.mirror_tid;
1060 if (parent->bref.type == HAMMER2_BREF_TYPE_VOLUME &&
1061 hmp->voldata.mirror_tid < child->bref.mirror_tid) {
1062 hmp->voldata.mirror_tid = child->bref.mirror_tid;
1066 * When can we safely clear the MOVED flag? Flushes down duplicate
1067 * paths can occur out of order, for example if an inode is moved
1068 * as part of a hardlink consolidation or if an inode is moved into
1069 * an indirect block indexed before the inode.
1071 * Only clear MOVED once all possible parents have been flushed.
1074 if (child->flags & HAMMER2_CHAIN_MOVED) {
1075 hammer2_chain_t *scan;
1078 spin_lock(&above->cst.spin);
1079 for (scan = above->first_parent; scan;
1080 scan = scan->next_parent) {
1081 if (scan->flags & HAMMER2_CHAIN_SUBMODIFIED) {
1086 spin_unlock(&above->cst.spin);
1088 atomic_clear_int(&child->flags, HAMMER2_CHAIN_MOVED);
1089 hammer2_chain_drop(child); /* flag */
1094 if (child->flags & HAMMER2_CHAIN_MOVED) {
1095 if (above->sharecnt == 1) {
1096 atomic_clear_int(&child->flags, HAMMER2_CHAIN_MOVED);
1097 hammer2_chain_drop(child); /* flag */
1103 * Unlock the child. This can wind up dropping the child's
1104 * last ref, removing it from the parent's RB tree, and deallocating
1105 * the structure. The RB_SCAN() our caller is doing handles the
1108 hammer2_chain_unlock(child);
1109 hammer2_chain_drop(child);
1110 spin_lock(&above->cst.spin);
1116 * The parent cleared SUBMODIFIED prior to the scan. If the child
1117 * still requires a flush (possibly due to being outside the current
1118 * synchronization zone), we must re-set SUBMODIFIED on the way back
1123 kprintf("G child %p 08x\n", child, child->flags);