2 * Copyright (c) 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
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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
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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_reblock.c,v 1.34 2008/11/13 02:18:43 dillon Exp $
37 * HAMMER reblocker - This code frees up fragmented physical space
39 * HAMMER only keeps track of free space on a big-block basis. A big-block
40 * containing holes can only be freed by migrating the remaining data in
41 * that big-block into a new big-block, then freeing the big-block.
43 * This function is called from an ioctl or via the hammer support thread.
48 static int hammer_reblock_helper(struct hammer_ioc_reblock *reblock,
49 hammer_cursor_t cursor,
50 hammer_btree_elm_t elm);
51 static int hammer_reblock_data(struct hammer_ioc_reblock *reblock,
52 hammer_cursor_t cursor, hammer_btree_elm_t elm);
53 static int hammer_reblock_leaf_node(struct hammer_ioc_reblock *reblock,
54 hammer_cursor_t cursor, hammer_btree_elm_t elm);
55 static int hammer_reblock_int_node(struct hammer_ioc_reblock *reblock,
56 hammer_cursor_t cursor, hammer_btree_elm_t elm);
59 hammer_ioc_reblock(hammer_transaction_t trans, hammer_inode_t ip,
60 struct hammer_ioc_reblock *reblock)
62 struct hammer_cursor cursor;
63 hammer_btree_elm_t elm;
70 * A fill level <= 20% is considered an emergency. free_level is
71 * inverted from fill_level.
73 if (reblock->free_level >= HAMMER_LARGEBLOCK_SIZE * 8 / 10)
74 slop = HAMMER_CHKSPC_EMERGENCY;
76 slop = HAMMER_CHKSPC_REBLOCK;
78 if ((reblock->key_beg.localization | reblock->key_end.localization) &
79 HAMMER_LOCALIZE_PSEUDOFS_MASK) {
82 if (reblock->key_beg.obj_id >= reblock->key_end.obj_id)
84 if (reblock->free_level < 0)
87 reblock->key_cur = reblock->key_beg;
88 reblock->key_cur.localization &= HAMMER_LOCALIZE_MASK;
89 reblock->key_cur.localization += ip->obj_localization;
92 seq = trans->hmp->flusher.act;
94 error = hammer_init_cursor(trans, &cursor, NULL, NULL);
96 hammer_done_cursor(&cursor);
99 cursor.key_beg.localization = reblock->key_cur.localization;
100 cursor.key_beg.obj_id = reblock->key_cur.obj_id;
101 cursor.key_beg.key = HAMMER_MIN_KEY;
102 cursor.key_beg.create_tid = 1;
103 cursor.key_beg.delete_tid = 0;
104 cursor.key_beg.rec_type = HAMMER_MIN_RECTYPE;
105 cursor.key_beg.obj_type = 0;
107 cursor.key_end.localization = (reblock->key_end.localization &
108 HAMMER_LOCALIZE_MASK) +
109 ip->obj_localization;
110 cursor.key_end.obj_id = reblock->key_end.obj_id;
111 cursor.key_end.key = HAMMER_MAX_KEY;
112 cursor.key_end.create_tid = HAMMER_MAX_TID - 1;
113 cursor.key_end.delete_tid = 0;
114 cursor.key_end.rec_type = HAMMER_MAX_RECTYPE;
115 cursor.key_end.obj_type = 0;
117 cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE;
118 cursor.flags |= HAMMER_CURSOR_BACKEND;
121 * This flag allows the btree scan code to return internal nodes,
122 * so we can reblock them in addition to the leafs. Only specify it
123 * if we intend to reblock B-Tree nodes.
125 if (reblock->head.flags & HAMMER_IOC_DO_BTREE)
126 cursor.flags |= HAMMER_CURSOR_REBLOCKING;
128 error = hammer_btree_first(&cursor);
131 * Internal or Leaf node
133 KKASSERT(cursor.index < cursor.node->ondisk->count);
134 elm = &cursor.node->ondisk->elms[cursor.index];
135 reblock->key_cur.obj_id = elm->base.obj_id;
136 reblock->key_cur.localization = elm->base.localization;
139 * Yield to more important tasks
141 if ((error = hammer_signal_check(trans->hmp)) != 0)
145 * If there is insufficient free space it may be due to
146 * reserved bigblocks, which flushing might fix.
148 * We must force a retest in case the unlocked cursor is
149 * moved to the end of the leaf, or moved to an internal
152 * WARNING: See warnings in hammer_unlock_cursor() function.
154 if (hammer_checkspace(trans->hmp, slop)) {
155 if (++checkspace_count == 10) {
159 hammer_unlock_cursor(&cursor);
160 cursor.flags |= HAMMER_CURSOR_RETEST;
161 hammer_flusher_wait(trans->hmp, seq);
162 hammer_lock_cursor(&cursor);
163 seq = hammer_flusher_async(trans->hmp, NULL);
168 * Acquiring the sync_lock prevents the operation from
169 * crossing a synchronization boundary.
171 * NOTE: cursor.node may have changed on return.
173 * WARNING: See warnings in hammer_unlock_cursor() function.
175 hammer_sync_lock_sh(trans);
176 error = hammer_reblock_helper(reblock, &cursor, elm);
177 hammer_sync_unlock(trans);
179 while (hammer_flusher_meta_halflimit(trans->hmp) ||
180 hammer_flusher_undo_exhausted(trans, 2)) {
181 hammer_unlock_cursor(&cursor);
182 hammer_flusher_wait(trans->hmp, seq);
183 hammer_lock_cursor(&cursor);
184 seq = hammer_flusher_async_one(trans->hmp);
188 * Setup for iteration, our cursor flags may be modified by
189 * other threads while we are unlocked.
191 cursor.flags |= HAMMER_CURSOR_ATEDISK;
194 * We allocate data buffers, which atm we don't track
195 * dirty levels for because we allow the kernel to write
196 * them. But if we allocate too many we can still deadlock
199 * WARNING: See warnings in hammer_unlock_cursor() function.
200 * (The cursor's node and element may change!)
203 hammer_unlock_cursor(&cursor);
204 bwillwrite(HAMMER_XBUFSIZE);
205 hammer_lock_cursor(&cursor);
209 error = hammer_btree_iterate(&cursor);
214 hammer_done_cursor(&cursor);
215 if (error == EWOULDBLOCK) {
216 hammer_flusher_sync(trans->hmp);
219 if (error == EDEADLK)
221 if (error == EINTR) {
222 reblock->head.flags |= HAMMER_IOC_HEAD_INTR;
226 reblock->key_cur.localization &= HAMMER_LOCALIZE_MASK;
231 * Reblock the B-Tree (leaf) node, record, and/or data if necessary.
233 * XXX We have no visibility into internal B-Tree nodes at the moment,
237 hammer_reblock_helper(struct hammer_ioc_reblock *reblock,
238 hammer_cursor_t cursor, hammer_btree_elm_t elm)
241 hammer_off_t tmp_offset;
242 hammer_node_ondisk_t ondisk;
243 struct hammer_btree_leaf_elm leaf;
250 hmp = cursor->trans->hmp;
253 * Reblock data. Note that data embedded in a record is reblocked
254 * by the record reblock code. Data processing only occurs at leaf
255 * nodes and for RECORD element types.
257 if (cursor->node->ondisk->type != HAMMER_BTREE_TYPE_LEAF)
259 if (elm->leaf.base.btype != HAMMER_BTREE_TYPE_RECORD)
261 tmp_offset = elm->leaf.data_offset;
268 * NOTE: Localization restrictions may also have been set-up, we can't
269 * just set the match flags willy-nilly here.
271 switch(elm->leaf.base.rec_type) {
272 case HAMMER_RECTYPE_INODE:
273 case HAMMER_RECTYPE_SNAPSHOT:
274 case HAMMER_RECTYPE_CONFIG:
275 iocflags = HAMMER_IOC_DO_INODES;
277 case HAMMER_RECTYPE_EXT:
278 case HAMMER_RECTYPE_FIX:
279 case HAMMER_RECTYPE_PFS:
280 case HAMMER_RECTYPE_DIRENTRY:
281 iocflags = HAMMER_IOC_DO_DIRS;
283 case HAMMER_RECTYPE_DATA:
284 case HAMMER_RECTYPE_DB:
285 iocflags = HAMMER_IOC_DO_DATA;
291 if (reblock->head.flags & iocflags) {
292 ++reblock->data_count;
293 reblock->data_byte_count += elm->leaf.data_len;
294 bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
295 if (hammer_debug_general & 0x4000)
296 kprintf("D %6d/%d\n", bytes, reblock->free_level);
297 if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
298 bytes >= reblock->free_level) {
300 * This is nasty, the uncache code may have to get
301 * vnode locks and because of that we can't hold
304 * WARNING: See warnings in hammer_unlock_cursor()
308 hammer_unlock_cursor(cursor);
309 hammer_io_direct_uncache(hmp, &leaf);
310 hammer_lock_cursor(cursor);
313 * elm may have become stale or invalid, reload it.
314 * ondisk variable is temporary only. Note that
315 * cursor->node and thus cursor->node->ondisk may
318 ondisk = cursor->node->ondisk;
319 elm = &ondisk->elms[cursor->index];
320 if (cursor->flags & HAMMER_CURSOR_RETEST) {
321 kprintf("hammer: debug: retest on "
322 "reblocker uncache\n");
324 } else if (ondisk->type != HAMMER_BTREE_TYPE_LEAF ||
325 cursor->index >= ondisk->count) {
326 kprintf("hammer: debug: shifted on "
327 "reblocker uncache\n");
329 } else if (bcmp(&elm->leaf, &leaf, sizeof(leaf))) {
330 kprintf("hammer: debug: changed on "
331 "reblocker uncache\n");
335 error = hammer_cursor_upgrade(cursor);
337 KKASSERT(cursor->index < ondisk->count);
338 error = hammer_reblock_data(reblock,
342 ++reblock->data_moves;
343 reblock->data_byte_moves += elm->leaf.data_len;
350 * Reblock a B-Tree internal or leaf node. A leaf node is reblocked
351 * on initial entry only (element 0). An internal node is reblocked
352 * when entered upward from its first leaf node only (also element 0).
353 * Further revisits of the internal node (index > 0) are ignored.
355 tmp_offset = cursor->node->node_offset;
356 if (cursor->index == 0 &&
357 error == 0 && (reblock->head.flags & HAMMER_IOC_DO_BTREE)) {
358 ++reblock->btree_count;
359 bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
360 if (hammer_debug_general & 0x4000)
361 kprintf("B %6d/%d\n", bytes, reblock->free_level);
362 if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
363 bytes >= reblock->free_level) {
364 error = hammer_cursor_upgrade(cursor);
366 if (cursor->parent) {
367 KKASSERT(cursor->parent_index <
368 cursor->parent->ondisk->count);
369 elm = &cursor->parent->ondisk->elms[cursor->parent_index];
373 switch(cursor->node->ondisk->type) {
374 case HAMMER_BTREE_TYPE_LEAF:
375 error = hammer_reblock_leaf_node(
376 reblock, cursor, elm);
378 case HAMMER_BTREE_TYPE_INTERNAL:
379 error = hammer_reblock_int_node(
380 reblock, cursor, elm);
383 panic("Illegal B-Tree node type");
387 ++reblock->btree_moves;
392 hammer_cursor_downgrade(cursor);
397 * Reblock a record's data. Both the B-Tree element and record pointers
398 * to the data must be adjusted.
401 hammer_reblock_data(struct hammer_ioc_reblock *reblock,
402 hammer_cursor_t cursor, hammer_btree_elm_t elm)
404 struct hammer_buffer *data_buffer = NULL;
405 hammer_off_t ndata_offset;
409 error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_DATA |
410 HAMMER_CURSOR_GET_LEAF);
413 ndata = hammer_alloc_data(cursor->trans, elm->leaf.data_len,
414 elm->leaf.base.rec_type,
415 &ndata_offset, &data_buffer,
419 hammer_io_notmeta(data_buffer);
424 hammer_modify_buffer(cursor->trans, data_buffer, NULL, 0);
425 bcopy(cursor->data, ndata, elm->leaf.data_len);
426 hammer_modify_buffer_done(data_buffer);
428 hammer_blockmap_free(cursor->trans,
429 elm->leaf.data_offset, elm->leaf.data_len);
431 hammer_modify_node(cursor->trans, cursor->node,
432 &elm->leaf.data_offset, sizeof(hammer_off_t));
433 elm->leaf.data_offset = ndata_offset;
434 hammer_modify_node_done(cursor->node);
438 hammer_rel_buffer(data_buffer, 0);
443 * Reblock a B-Tree leaf node. The parent must be adjusted to point to
444 * the new copy of the leaf node.
446 * elm is a pointer to the parent element pointing at cursor.node.
449 hammer_reblock_leaf_node(struct hammer_ioc_reblock *reblock,
450 hammer_cursor_t cursor, hammer_btree_elm_t elm)
457 * Don't supply a hint when allocating the leaf. Fills are done
458 * from the leaf upwards.
460 onode = cursor->node;
461 nnode = hammer_alloc_btree(cursor->trans, 0, &error);
469 hammer_lock_ex(&nnode->lock);
470 hammer_modify_node_noundo(cursor->trans, nnode);
471 bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));
475 * We are not the root of the B-Tree
477 hammer_modify_node(cursor->trans, cursor->parent,
478 &elm->internal.subtree_offset,
479 sizeof(elm->internal.subtree_offset));
480 elm->internal.subtree_offset = nnode->node_offset;
481 hammer_modify_node_done(cursor->parent);
484 * We are the root of the B-Tree
486 hammer_volume_t volume;
488 volume = hammer_get_root_volume(cursor->trans->hmp, &error);
489 KKASSERT(error == 0);
491 hammer_modify_volume_field(cursor->trans, volume,
493 volume->ondisk->vol0_btree_root = nnode->node_offset;
494 hammer_modify_volume_done(volume);
495 hammer_rel_volume(volume, 0);
498 hammer_cursor_replaced_node(onode, nnode);
499 hammer_delete_node(cursor->trans, onode);
501 if (hammer_debug_general & 0x4000) {
502 kprintf("REBLOCK LNODE %016llx -> %016llx\n",
503 (long long)onode->node_offset,
504 (long long)nnode->node_offset);
506 hammer_modify_node_done(nnode);
507 cursor->node = nnode;
509 hammer_unlock(&onode->lock);
510 hammer_rel_node(onode);
516 * Reblock a B-Tree internal node. The parent must be adjusted to point to
517 * the new copy of the internal node, and the node's children's parent
518 * pointers must also be adjusted to point to the new copy.
520 * elm is a pointer to the parent element pointing at cursor.node.
523 hammer_reblock_int_node(struct hammer_ioc_reblock *reblock,
524 hammer_cursor_t cursor, hammer_btree_elm_t elm)
526 struct hammer_node_lock lockroot;
533 hammer_node_lock_init(&lockroot, cursor->node);
534 error = hammer_btree_lock_children(cursor, 1, &lockroot, NULL);
539 * The internal node is visited after recursing through its
540 * first element. Use the subtree offset allocated for that
541 * element as a hint for allocating the internal node.
543 onode = cursor->node;
544 if (onode->ondisk->count)
545 hint = onode->ondisk->elms[0].internal.subtree_offset;
548 nnode = hammer_alloc_btree(cursor->trans, hint, &error);
554 * Move the node. Adjust the parent's pointer to us first.
556 hammer_lock_ex(&nnode->lock);
557 hammer_modify_node_noundo(cursor->trans, nnode);
558 bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));
562 * We are not the root of the B-Tree
564 hammer_modify_node(cursor->trans, cursor->parent,
565 &elm->internal.subtree_offset,
566 sizeof(elm->internal.subtree_offset));
567 elm->internal.subtree_offset = nnode->node_offset;
568 hammer_modify_node_done(cursor->parent);
571 * We are the root of the B-Tree
573 hammer_volume_t volume;
575 volume = hammer_get_root_volume(cursor->trans->hmp, &error);
576 KKASSERT(error == 0);
578 hammer_modify_volume_field(cursor->trans, volume,
580 volume->ondisk->vol0_btree_root = nnode->node_offset;
581 hammer_modify_volume_done(volume);
582 hammer_rel_volume(volume, 0);
586 * Now adjust our children's pointers to us.
588 for (i = 0; i < nnode->ondisk->count; ++i) {
589 elm = &nnode->ondisk->elms[i];
590 error = btree_set_parent(cursor->trans, nnode, elm);
592 panic("reblock internal node: fixup problem");
598 * The new node replaces the current node in the cursor. The cursor
599 * expects it to be locked so leave it locked. Discard onode.
601 hammer_cursor_replaced_node(onode, nnode);
602 hammer_delete_node(cursor->trans, onode);
604 if (hammer_debug_general & 0x4000) {
605 kprintf("REBLOCK INODE %016llx -> %016llx\n",
606 (long long)onode->node_offset,
607 (long long)nnode->node_offset);
609 hammer_modify_node_done(nnode);
610 cursor->node = nnode;
612 hammer_unlock(&onode->lock);
613 hammer_rel_node(onode);
616 hammer_btree_unlock_children(cursor->trans->hmp, &lockroot, NULL);