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
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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19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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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_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 elm = &cursor.node->ondisk->elms[cursor.index];
134 reblock->key_cur.obj_id = elm->base.obj_id;
135 reblock->key_cur.localization = elm->base.localization;
138 * Yield to more important tasks
140 if ((error = hammer_signal_check(trans->hmp)) != 0)
144 * If there is insufficient free space it may be due to
145 * reserved bigblocks, which flushing might fix.
147 * WARNING: See warnings in hammer_unlock_cursor() function.
149 if (hammer_checkspace(trans->hmp, slop)) {
150 if (++checkspace_count == 10) {
154 hammer_unlock_cursor(&cursor);
155 hammer_flusher_wait(trans->hmp, seq);
156 hammer_lock_cursor(&cursor);
157 seq = hammer_flusher_async(trans->hmp, NULL);
162 * Acquiring the sync_lock prevents the operation from
163 * crossing a synchronization boundary.
165 * NOTE: cursor.node may have changed on return.
167 * WARNING: See warnings in hammer_unlock_cursor() function.
169 hammer_sync_lock_sh(trans);
170 error = hammer_reblock_helper(reblock, &cursor, elm);
171 hammer_sync_unlock(trans);
173 while (hammer_flusher_meta_halflimit(trans->hmp) ||
174 hammer_flusher_undo_exhausted(trans, 2)) {
175 hammer_unlock_cursor(&cursor);
176 hammer_flusher_wait(trans->hmp, seq);
177 hammer_lock_cursor(&cursor);
178 seq = hammer_flusher_async_one(trans->hmp);
182 * Setup for iteration, our cursor flags may be modified by
183 * other threads while we are unlocked.
185 cursor.flags |= HAMMER_CURSOR_ATEDISK;
188 * We allocate data buffers, which atm we don't track
189 * dirty levels for because we allow the kernel to write
190 * them. But if we allocate too many we can still deadlock
193 * WARNING: See warnings in hammer_unlock_cursor() function.
194 * (The cursor's node and element may change!)
197 hammer_unlock_cursor(&cursor);
198 bwillwrite(HAMMER_XBUFSIZE);
199 hammer_lock_cursor(&cursor);
203 error = hammer_btree_iterate(&cursor);
209 hammer_done_cursor(&cursor);
210 if (error == EWOULDBLOCK) {
211 hammer_flusher_sync(trans->hmp);
214 if (error == EDEADLK)
216 if (error == EINTR) {
217 reblock->head.flags |= HAMMER_IOC_HEAD_INTR;
221 reblock->key_cur.localization &= HAMMER_LOCALIZE_MASK;
226 * Reblock the B-Tree (leaf) node, record, and/or data if necessary.
228 * XXX We have no visibility into internal B-Tree nodes at the moment,
232 hammer_reblock_helper(struct hammer_ioc_reblock *reblock,
233 hammer_cursor_t cursor, hammer_btree_elm_t elm)
236 hammer_off_t tmp_offset;
237 hammer_node_ondisk_t ondisk;
238 struct hammer_btree_leaf_elm leaf;
245 hmp = cursor->trans->hmp;
248 * Reblock data. Note that data embedded in a record is reblocked
249 * by the record reblock code. Data processing only occurs at leaf
250 * nodes and for RECORD element types.
252 if (cursor->node->ondisk->type != HAMMER_BTREE_TYPE_LEAF)
254 if (elm->leaf.base.btype != HAMMER_BTREE_TYPE_RECORD)
256 tmp_offset = elm->leaf.data_offset;
263 * NOTE: Localization restrictions may also have been set-up, we can't
264 * just set the match flags willy-nilly here.
266 switch(elm->leaf.base.rec_type) {
267 case HAMMER_RECTYPE_INODE:
268 case HAMMER_RECTYPE_SNAPSHOT:
269 case HAMMER_RECTYPE_CONFIG:
270 iocflags = HAMMER_IOC_DO_INODES;
272 case HAMMER_RECTYPE_EXT:
273 case HAMMER_RECTYPE_FIX:
274 case HAMMER_RECTYPE_PFS:
275 case HAMMER_RECTYPE_DIRENTRY:
276 iocflags = HAMMER_IOC_DO_DIRS;
278 case HAMMER_RECTYPE_DATA:
279 case HAMMER_RECTYPE_DB:
280 iocflags = HAMMER_IOC_DO_DATA;
286 if (reblock->head.flags & iocflags) {
287 ++reblock->data_count;
288 reblock->data_byte_count += elm->leaf.data_len;
289 bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
290 if (hammer_debug_general & 0x4000)
291 kprintf("D %6d/%d\n", bytes, reblock->free_level);
292 if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
293 bytes >= reblock->free_level) {
295 * This is nasty, the uncache code may have to get
296 * vnode locks and because of that we can't hold
299 * WARNING: See warnings in hammer_unlock_cursor()
303 hammer_unlock_cursor(cursor);
304 hammer_io_direct_uncache(hmp, &leaf);
305 hammer_lock_cursor(cursor);
308 * elm may have become stale or invalid, reload it.
309 * ondisk variable is temporary only. Note that
310 * cursor->node and thus cursor->node->ondisk may
313 ondisk = cursor->node->ondisk;
314 elm = &ondisk->elms[cursor->index];
315 if (cursor->flags & HAMMER_CURSOR_RETEST) {
316 kprintf("hammer: debug: retest on "
317 "reblocker uncache\n");
319 } else if (ondisk->type != HAMMER_BTREE_TYPE_LEAF ||
320 cursor->index >= ondisk->count) {
321 kprintf("hammer: debug: shifted on "
322 "reblocker uncache\n");
324 } else if (bcmp(&elm->leaf, &leaf, sizeof(leaf))) {
325 kprintf("hammer: debug: changed on "
326 "reblocker uncache\n");
330 error = hammer_cursor_upgrade(cursor);
332 error = hammer_reblock_data(reblock,
336 ++reblock->data_moves;
337 reblock->data_byte_moves += elm->leaf.data_len;
344 * Reblock a B-Tree internal or leaf node. A leaf node is reblocked
345 * on initial entry only (element 0). An internal node is reblocked
346 * when entered upward from its first leaf node only (also element 0).
347 * Further revisits of the internal node (index > 0) are ignored.
349 tmp_offset = cursor->node->node_offset;
350 if (cursor->index == 0 &&
351 error == 0 && (reblock->head.flags & HAMMER_IOC_DO_BTREE)) {
352 ++reblock->btree_count;
353 bytes = hammer_blockmap_getfree(hmp, tmp_offset, &cur, &error);
354 if (hammer_debug_general & 0x4000)
355 kprintf("B %6d/%d\n", bytes, reblock->free_level);
356 if (error == 0 && (cur == 0 || reblock->free_level == 0) &&
357 bytes >= reblock->free_level) {
358 error = hammer_cursor_upgrade(cursor);
361 elm = &cursor->parent->ondisk->elms[cursor->parent_index];
364 switch(cursor->node->ondisk->type) {
365 case HAMMER_BTREE_TYPE_LEAF:
366 error = hammer_reblock_leaf_node(
367 reblock, cursor, elm);
369 case HAMMER_BTREE_TYPE_INTERNAL:
370 error = hammer_reblock_int_node(
371 reblock, cursor, elm);
374 panic("Illegal B-Tree node type");
378 ++reblock->btree_moves;
383 hammer_cursor_downgrade(cursor);
388 * Reblock a record's data. Both the B-Tree element and record pointers
389 * to the data must be adjusted.
392 hammer_reblock_data(struct hammer_ioc_reblock *reblock,
393 hammer_cursor_t cursor, hammer_btree_elm_t elm)
395 struct hammer_buffer *data_buffer = NULL;
396 hammer_off_t ndata_offset;
400 error = hammer_btree_extract(cursor, HAMMER_CURSOR_GET_DATA |
401 HAMMER_CURSOR_GET_LEAF);
404 ndata = hammer_alloc_data(cursor->trans, elm->leaf.data_len,
405 elm->leaf.base.rec_type,
406 &ndata_offset, &data_buffer,
410 hammer_io_notmeta(data_buffer);
415 hammer_modify_buffer(cursor->trans, data_buffer, NULL, 0);
416 bcopy(cursor->data, ndata, elm->leaf.data_len);
417 hammer_modify_buffer_done(data_buffer);
419 hammer_blockmap_free(cursor->trans,
420 elm->leaf.data_offset, elm->leaf.data_len);
422 hammer_modify_node(cursor->trans, cursor->node,
423 &elm->leaf.data_offset, sizeof(hammer_off_t));
424 elm->leaf.data_offset = ndata_offset;
425 hammer_modify_node_done(cursor->node);
429 hammer_rel_buffer(data_buffer, 0);
434 * Reblock a B-Tree leaf node. The parent must be adjusted to point to
435 * the new copy of the leaf node.
437 * elm is a pointer to the parent element pointing at cursor.node.
440 hammer_reblock_leaf_node(struct hammer_ioc_reblock *reblock,
441 hammer_cursor_t cursor, hammer_btree_elm_t elm)
448 * Don't supply a hint when allocating the leaf. Fills are done
449 * from the leaf upwards.
451 onode = cursor->node;
452 nnode = hammer_alloc_btree(cursor->trans, 0, &error);
460 hammer_lock_ex(&nnode->lock);
461 hammer_modify_node_noundo(cursor->trans, nnode);
462 bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));
466 * We are not the root of the B-Tree
468 hammer_modify_node(cursor->trans, cursor->parent,
469 &elm->internal.subtree_offset,
470 sizeof(elm->internal.subtree_offset));
471 elm->internal.subtree_offset = nnode->node_offset;
472 hammer_modify_node_done(cursor->parent);
475 * We are the root of the B-Tree
477 hammer_volume_t volume;
479 volume = hammer_get_root_volume(cursor->trans->hmp, &error);
480 KKASSERT(error == 0);
482 hammer_modify_volume_field(cursor->trans, volume,
484 volume->ondisk->vol0_btree_root = nnode->node_offset;
485 hammer_modify_volume_done(volume);
486 hammer_rel_volume(volume, 0);
489 hammer_cursor_replaced_node(onode, nnode);
490 hammer_delete_node(cursor->trans, onode);
492 if (hammer_debug_general & 0x4000) {
493 kprintf("REBLOCK LNODE %016llx -> %016llx\n",
494 (long long)onode->node_offset,
495 (long long)nnode->node_offset);
497 hammer_modify_node_done(nnode);
498 cursor->node = nnode;
500 hammer_unlock(&onode->lock);
501 hammer_rel_node(onode);
507 * Reblock a B-Tree internal node. The parent must be adjusted to point to
508 * the new copy of the internal node, and the node's children's parent
509 * pointers must also be adjusted to point to the new copy.
511 * elm is a pointer to the parent element pointing at cursor.node.
514 hammer_reblock_int_node(struct hammer_ioc_reblock *reblock,
515 hammer_cursor_t cursor, hammer_btree_elm_t elm)
517 struct hammer_node_lock lockroot;
524 hammer_node_lock_init(&lockroot, cursor->node);
525 error = hammer_btree_lock_children(cursor, 1, &lockroot, NULL);
530 * The internal node is visited after recursing through its
531 * first element. Use the subtree offset allocated for that
532 * element as a hint for allocating the internal node.
534 onode = cursor->node;
535 if (onode->ondisk->count)
536 hint = onode->ondisk->elms[0].internal.subtree_offset;
539 nnode = hammer_alloc_btree(cursor->trans, hint, &error);
545 * Move the node. Adjust the parent's pointer to us first.
547 hammer_lock_ex(&nnode->lock);
548 hammer_modify_node_noundo(cursor->trans, nnode);
549 bcopy(onode->ondisk, nnode->ondisk, sizeof(*nnode->ondisk));
553 * We are not the root of the B-Tree
555 hammer_modify_node(cursor->trans, cursor->parent,
556 &elm->internal.subtree_offset,
557 sizeof(elm->internal.subtree_offset));
558 elm->internal.subtree_offset = nnode->node_offset;
559 hammer_modify_node_done(cursor->parent);
562 * We are the root of the B-Tree
564 hammer_volume_t volume;
566 volume = hammer_get_root_volume(cursor->trans->hmp, &error);
567 KKASSERT(error == 0);
569 hammer_modify_volume_field(cursor->trans, volume,
571 volume->ondisk->vol0_btree_root = nnode->node_offset;
572 hammer_modify_volume_done(volume);
573 hammer_rel_volume(volume, 0);
577 * Now adjust our children's pointers to us.
579 for (i = 0; i < nnode->ondisk->count; ++i) {
580 elm = &nnode->ondisk->elms[i];
581 error = btree_set_parent(cursor->trans, nnode, elm);
583 panic("reblock internal node: fixup problem");
589 * The new node replaces the current node in the cursor. The cursor
590 * expects it to be locked so leave it locked. Discard onode.
592 hammer_cursor_replaced_node(onode, nnode);
593 hammer_delete_node(cursor->trans, onode);
595 if (hammer_debug_general & 0x4000) {
596 kprintf("REBLOCK INODE %016llx -> %016llx\n",
597 (long long)onode->node_offset,
598 (long long)nnode->node_offset);
600 hammer_modify_node_done(nnode);
601 cursor->node = nnode;
603 hammer_unlock(&onode->lock);
604 hammer_rel_node(onode);
607 hammer_btree_unlock_children(cursor->trans->hmp, &lockroot, NULL);