2 * Copyright (C) 2013 Fusion IO. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/slab.h>
20 #include "btrfs-tests.h"
22 #include "../disk-io.h"
23 #include "../free-space-cache.h"
25 #define BITS_PER_BITMAP (PAGE_SIZE * 8)
28 * This test just does basic sanity checking, making sure we can add an extent
29 * entry and remove space from either end and the middle, and make sure we can
30 * remove space that covers adjacent extent entries.
32 static int test_extents(struct btrfs_block_group_cache *cache)
36 test_msg("Running extent only tests\n");
38 /* First just make sure we can remove an entire entry */
39 ret = btrfs_add_free_space(cache, 0, SZ_4M);
41 test_msg("Error adding initial extents %d\n", ret);
45 ret = btrfs_remove_free_space(cache, 0, SZ_4M);
47 test_msg("Error removing extent %d\n", ret);
51 if (test_check_exists(cache, 0, SZ_4M)) {
52 test_msg("Full remove left some lingering space\n");
56 /* Ok edge and middle cases now */
57 ret = btrfs_add_free_space(cache, 0, SZ_4M);
59 test_msg("Error adding half extent %d\n", ret);
63 ret = btrfs_remove_free_space(cache, 3 * SZ_1M, SZ_1M);
65 test_msg("Error removing tail end %d\n", ret);
69 ret = btrfs_remove_free_space(cache, 0, SZ_1M);
71 test_msg("Error removing front end %d\n", ret);
75 ret = btrfs_remove_free_space(cache, SZ_2M, 4096);
77 test_msg("Error removing middle piece %d\n", ret);
81 if (test_check_exists(cache, 0, SZ_1M)) {
82 test_msg("Still have space at the front\n");
86 if (test_check_exists(cache, SZ_2M, 4096)) {
87 test_msg("Still have space in the middle\n");
91 if (test_check_exists(cache, 3 * SZ_1M, SZ_1M)) {
92 test_msg("Still have space at the end\n");
97 __btrfs_remove_free_space_cache(cache->free_space_ctl);
102 static int test_bitmaps(struct btrfs_block_group_cache *cache)
104 u64 next_bitmap_offset;
107 test_msg("Running bitmap only tests\n");
109 ret = test_add_free_space_entry(cache, 0, SZ_4M, 1);
111 test_msg("Couldn't create a bitmap entry %d\n", ret);
115 ret = btrfs_remove_free_space(cache, 0, SZ_4M);
117 test_msg("Error removing bitmap full range %d\n", ret);
121 if (test_check_exists(cache, 0, SZ_4M)) {
122 test_msg("Left some space in bitmap\n");
126 ret = test_add_free_space_entry(cache, 0, SZ_4M, 1);
128 test_msg("Couldn't add to our bitmap entry %d\n", ret);
132 ret = btrfs_remove_free_space(cache, SZ_1M, SZ_2M);
134 test_msg("Couldn't remove middle chunk %d\n", ret);
139 * The first bitmap we have starts at offset 0 so the next one is just
140 * at the end of the first bitmap.
142 next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
144 /* Test a bit straddling two bitmaps */
145 ret = test_add_free_space_entry(cache, next_bitmap_offset - SZ_2M,
148 test_msg("Couldn't add space that straddles two bitmaps %d\n",
153 ret = btrfs_remove_free_space(cache, next_bitmap_offset - SZ_1M, SZ_2M);
155 test_msg("Couldn't remove overlapping space %d\n", ret);
159 if (test_check_exists(cache, next_bitmap_offset - SZ_1M, SZ_2M)) {
160 test_msg("Left some space when removing overlapping\n");
164 __btrfs_remove_free_space_cache(cache->free_space_ctl);
169 /* This is the high grade jackassery */
170 static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
172 u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
175 test_msg("Running bitmap and extent tests\n");
178 * First let's do something simple, an extent at the same offset as the
179 * bitmap, but the free space completely in the extent and then
180 * completely in the bitmap.
182 ret = test_add_free_space_entry(cache, SZ_4M, SZ_1M, 1);
184 test_msg("Couldn't create bitmap entry %d\n", ret);
188 ret = test_add_free_space_entry(cache, 0, SZ_1M, 0);
190 test_msg("Couldn't add extent entry %d\n", ret);
194 ret = btrfs_remove_free_space(cache, 0, SZ_1M);
196 test_msg("Couldn't remove extent entry %d\n", ret);
200 if (test_check_exists(cache, 0, SZ_1M)) {
201 test_msg("Left remnants after our remove\n");
205 /* Now to add back the extent entry and remove from the bitmap */
206 ret = test_add_free_space_entry(cache, 0, SZ_1M, 0);
208 test_msg("Couldn't re-add extent entry %d\n", ret);
212 ret = btrfs_remove_free_space(cache, SZ_4M, SZ_1M);
214 test_msg("Couldn't remove from bitmap %d\n", ret);
218 if (test_check_exists(cache, SZ_4M, SZ_1M)) {
219 test_msg("Left remnants in the bitmap\n");
224 * Ok so a little more evil, extent entry and bitmap at the same offset,
225 * removing an overlapping chunk.
227 ret = test_add_free_space_entry(cache, SZ_1M, SZ_4M, 1);
229 test_msg("Couldn't add to a bitmap %d\n", ret);
233 ret = btrfs_remove_free_space(cache, SZ_512K, 3 * SZ_1M);
235 test_msg("Couldn't remove overlapping space %d\n", ret);
239 if (test_check_exists(cache, SZ_512K, 3 * SZ_1M)) {
240 test_msg("Left over pieces after removing overlapping\n");
244 __btrfs_remove_free_space_cache(cache->free_space_ctl);
246 /* Now with the extent entry offset into the bitmap */
247 ret = test_add_free_space_entry(cache, SZ_4M, SZ_4M, 1);
249 test_msg("Couldn't add space to the bitmap %d\n", ret);
253 ret = test_add_free_space_entry(cache, SZ_2M, SZ_2M, 0);
255 test_msg("Couldn't add extent to the cache %d\n", ret);
259 ret = btrfs_remove_free_space(cache, 3 * SZ_1M, SZ_4M);
261 test_msg("Problem removing overlapping space %d\n", ret);
265 if (test_check_exists(cache, 3 * SZ_1M, SZ_4M)) {
266 test_msg("Left something behind when removing space");
271 * This has blown up in the past, the extent entry starts before the
272 * bitmap entry, but we're trying to remove an offset that falls
273 * completely within the bitmap range and is in both the extent entry
274 * and the bitmap entry, looks like this
280 __btrfs_remove_free_space_cache(cache->free_space_ctl);
281 ret = test_add_free_space_entry(cache, bitmap_offset + SZ_4M, SZ_4M, 1);
283 test_msg("Couldn't add bitmap %d\n", ret);
287 ret = test_add_free_space_entry(cache, bitmap_offset - SZ_1M,
290 test_msg("Couldn't add extent entry %d\n", ret);
294 ret = btrfs_remove_free_space(cache, bitmap_offset + SZ_1M, 5 * SZ_1M);
296 test_msg("Failed to free our space %d\n", ret);
300 if (test_check_exists(cache, bitmap_offset + SZ_1M, 5 * SZ_1M)) {
301 test_msg("Left stuff over\n");
305 __btrfs_remove_free_space_cache(cache->free_space_ctl);
308 * This blew up before, we have part of the free space in a bitmap and
309 * then the entirety of the rest of the space in an extent. This used
310 * to return -EAGAIN back from btrfs_remove_extent, make sure this
313 ret = test_add_free_space_entry(cache, SZ_1M, SZ_2M, 1);
315 test_msg("Couldn't add bitmap entry %d\n", ret);
319 ret = test_add_free_space_entry(cache, 3 * SZ_1M, SZ_1M, 0);
321 test_msg("Couldn't add extent entry %d\n", ret);
325 ret = btrfs_remove_free_space(cache, SZ_1M, 3 * SZ_1M);
327 test_msg("Error removing bitmap and extent overlapping %d\n", ret);
331 __btrfs_remove_free_space_cache(cache->free_space_ctl);
335 /* Used by test_steal_space_from_bitmap_to_extent(). */
336 static bool test_use_bitmap(struct btrfs_free_space_ctl *ctl,
337 struct btrfs_free_space *info)
339 return ctl->free_extents > 0;
342 /* Used by test_steal_space_from_bitmap_to_extent(). */
344 check_num_extents_and_bitmaps(const struct btrfs_block_group_cache *cache,
345 const int num_extents,
346 const int num_bitmaps)
348 if (cache->free_space_ctl->free_extents != num_extents) {
349 test_msg("Incorrect # of extent entries in the cache: %d, expected %d\n",
350 cache->free_space_ctl->free_extents, num_extents);
353 if (cache->free_space_ctl->total_bitmaps != num_bitmaps) {
354 test_msg("Incorrect # of extent entries in the cache: %d, expected %d\n",
355 cache->free_space_ctl->total_bitmaps, num_bitmaps);
361 /* Used by test_steal_space_from_bitmap_to_extent(). */
362 static int check_cache_empty(struct btrfs_block_group_cache *cache)
368 * Now lets confirm that there's absolutely no free space left to
371 if (cache->free_space_ctl->free_space != 0) {
372 test_msg("Cache free space is not 0\n");
376 /* And any allocation request, no matter how small, should fail now. */
377 offset = btrfs_find_space_for_alloc(cache, 0, 4096, 0,
380 test_msg("Space allocation did not fail, returned offset: %llu",
385 /* And no extent nor bitmap entries in the cache anymore. */
386 return check_num_extents_and_bitmaps(cache, 0, 0);
390 * Before we were able to steal free space from a bitmap entry to an extent
391 * entry, we could end up with 2 entries representing a contiguous free space.
392 * One would be an extent entry and the other a bitmap entry. Since in order
393 * to allocate space to a caller we use only 1 entry, we couldn't return that
394 * whole range to the caller if it was requested. This forced the caller to
395 * either assume ENOSPC or perform several smaller space allocations, which
396 * wasn't optimal as they could be spread all over the block group while under
397 * concurrency (extra overhead and fragmentation).
399 * This stealing approach is beneficial, since we always prefer to allocate
400 * from extent entries, both for clustered and non-clustered allocation
404 test_steal_space_from_bitmap_to_extent(struct btrfs_block_group_cache *cache)
409 const struct btrfs_free_space_op test_free_space_ops = {
410 .recalc_thresholds = cache->free_space_ctl->op->recalc_thresholds,
411 .use_bitmap = test_use_bitmap,
413 const struct btrfs_free_space_op *orig_free_space_ops;
415 test_msg("Running space stealing from bitmap to extent\n");
418 * For this test, we want to ensure we end up with an extent entry
419 * immediately adjacent to a bitmap entry, where the bitmap starts
420 * at an offset where the extent entry ends. We keep adding and
421 * removing free space to reach into this state, but to get there
422 * we need to reach a point where marking new free space doesn't
423 * result in adding new extent entries or merging the new space
424 * with existing extent entries - the space ends up being marked
425 * in an existing bitmap that covers the new free space range.
427 * To get there, we need to reach the threshold defined set at
428 * cache->free_space_ctl->extents_thresh, which currently is
429 * 256 extents on a x86_64 system at least, and a few other
430 * conditions (check free_space_cache.c). Instead of making the
431 * test much longer and complicated, use a "use_bitmap" operation
432 * that forces use of bitmaps as soon as we have at least 1
435 orig_free_space_ops = cache->free_space_ctl->op;
436 cache->free_space_ctl->op = &test_free_space_ops;
439 * Extent entry covering free space range [128Mb - 256Kb, 128Mb - 128Kb[
441 ret = test_add_free_space_entry(cache, SZ_128M - SZ_256K, SZ_128K, 0);
443 test_msg("Couldn't add extent entry %d\n", ret);
447 /* Bitmap entry covering free space range [128Mb + 512Kb, 256Mb[ */
448 ret = test_add_free_space_entry(cache, SZ_128M + SZ_512K,
449 SZ_128M - SZ_512K, 1);
451 test_msg("Couldn't add bitmap entry %d\n", ret);
455 ret = check_num_extents_and_bitmaps(cache, 2, 1);
460 * Now make only the first 256Kb of the bitmap marked as free, so that
461 * we end up with only the following ranges marked as free space:
463 * [128Mb - 256Kb, 128Mb - 128Kb[
464 * [128Mb + 512Kb, 128Mb + 768Kb[
466 ret = btrfs_remove_free_space(cache,
467 SZ_128M + 768 * SZ_1K,
468 SZ_128M - 768 * SZ_1K);
470 test_msg("Failed to free part of bitmap space %d\n", ret);
474 /* Confirm that only those 2 ranges are marked as free. */
475 if (!test_check_exists(cache, SZ_128M - SZ_256K, SZ_128K)) {
476 test_msg("Free space range missing\n");
479 if (!test_check_exists(cache, SZ_128M + SZ_512K, SZ_256K)) {
480 test_msg("Free space range missing\n");
485 * Confirm that the bitmap range [128Mb + 768Kb, 256Mb[ isn't marked
488 if (test_check_exists(cache, SZ_128M + 768 * SZ_1K,
489 SZ_128M - 768 * SZ_1K)) {
490 test_msg("Bitmap region not removed from space cache\n");
495 * Confirm that the region [128Mb + 256Kb, 128Mb + 512Kb[, which is
496 * covered by the bitmap, isn't marked as free.
498 if (test_check_exists(cache, SZ_128M + SZ_256K, SZ_256K)) {
499 test_msg("Invalid bitmap region marked as free\n");
504 * Confirm that the region [128Mb, 128Mb + 256Kb[, which is covered
505 * by the bitmap too, isn't marked as free either.
507 if (test_check_exists(cache, SZ_128M, SZ_256K)) {
508 test_msg("Invalid bitmap region marked as free\n");
513 * Now lets mark the region [128Mb, 128Mb + 512Kb[ as free too. But,
514 * lets make sure the free space cache marks it as free in the bitmap,
515 * and doesn't insert a new extent entry to represent this region.
517 ret = btrfs_add_free_space(cache, SZ_128M, SZ_512K);
519 test_msg("Error adding free space: %d\n", ret);
522 /* Confirm the region is marked as free. */
523 if (!test_check_exists(cache, SZ_128M, SZ_512K)) {
524 test_msg("Bitmap region not marked as free\n");
529 * Confirm that no new extent entries or bitmap entries were added to
530 * the cache after adding that free space region.
532 ret = check_num_extents_and_bitmaps(cache, 2, 1);
537 * Now lets add a small free space region to the right of the previous
538 * one, which is not contiguous with it and is part of the bitmap too.
539 * The goal is to test that the bitmap entry space stealing doesn't
540 * steal this space region.
542 ret = btrfs_add_free_space(cache, SZ_128M + SZ_16M, 4096);
544 test_msg("Error adding free space: %d\n", ret);
549 * Confirm that no new extent entries or bitmap entries were added to
550 * the cache after adding that free space region.
552 ret = check_num_extents_and_bitmaps(cache, 2, 1);
557 * Now mark the region [128Mb - 128Kb, 128Mb[ as free too. This will
558 * expand the range covered by the existing extent entry that represents
559 * the free space [128Mb - 256Kb, 128Mb - 128Kb[.
561 ret = btrfs_add_free_space(cache, SZ_128M - SZ_128K, SZ_128K);
563 test_msg("Error adding free space: %d\n", ret);
566 /* Confirm the region is marked as free. */
567 if (!test_check_exists(cache, SZ_128M - SZ_128K, SZ_128K)) {
568 test_msg("Extent region not marked as free\n");
573 * Confirm that our extent entry didn't stole all free space from the
574 * bitmap, because of the small 4Kb free space region.
576 ret = check_num_extents_and_bitmaps(cache, 2, 1);
581 * So now we have the range [128Mb - 256Kb, 128Mb + 768Kb[ as free
582 * space. Without stealing bitmap free space into extent entry space,
583 * we would have all this free space represented by 2 entries in the
586 * extent entry covering range: [128Mb - 256Kb, 128Mb[
587 * bitmap entry covering range: [128Mb, 128Mb + 768Kb[
589 * Attempting to allocate the whole free space (1Mb) would fail, because
590 * we can't allocate from multiple entries.
591 * With the bitmap free space stealing, we get a single extent entry
592 * that represents the 1Mb free space, and therefore we're able to
593 * allocate the whole free space at once.
595 if (!test_check_exists(cache, SZ_128M - SZ_256K, SZ_1M)) {
596 test_msg("Expected region not marked as free\n");
600 if (cache->free_space_ctl->free_space != (SZ_1M + 4096)) {
601 test_msg("Cache free space is not 1Mb + 4Kb\n");
605 offset = btrfs_find_space_for_alloc(cache,
608 if (offset != (SZ_128M - SZ_256K)) {
609 test_msg("Failed to allocate 1Mb from space cache, returned offset is: %llu\n",
614 /* All that remains is a 4Kb free space region in a bitmap. Confirm. */
615 ret = check_num_extents_and_bitmaps(cache, 1, 1);
619 if (cache->free_space_ctl->free_space != 4096) {
620 test_msg("Cache free space is not 4Kb\n");
624 offset = btrfs_find_space_for_alloc(cache,
627 if (offset != (SZ_128M + SZ_16M)) {
628 test_msg("Failed to allocate 4Kb from space cache, returned offset is: %llu\n",
633 ret = check_cache_empty(cache);
637 __btrfs_remove_free_space_cache(cache->free_space_ctl);
640 * Now test a similar scenario, but where our extent entry is located
641 * to the right of the bitmap entry, so that we can check that stealing
642 * space from a bitmap to the front of an extent entry works.
646 * Extent entry covering free space range [128Mb + 128Kb, 128Mb + 256Kb[
648 ret = test_add_free_space_entry(cache, SZ_128M + SZ_128K, SZ_128K, 0);
650 test_msg("Couldn't add extent entry %d\n", ret);
654 /* Bitmap entry covering free space range [0, 128Mb - 512Kb[ */
655 ret = test_add_free_space_entry(cache, 0, SZ_128M - SZ_512K, 1);
657 test_msg("Couldn't add bitmap entry %d\n", ret);
661 ret = check_num_extents_and_bitmaps(cache, 2, 1);
666 * Now make only the last 256Kb of the bitmap marked as free, so that
667 * we end up with only the following ranges marked as free space:
669 * [128Mb + 128b, 128Mb + 256Kb[
670 * [128Mb - 768Kb, 128Mb - 512Kb[
672 ret = btrfs_remove_free_space(cache, 0, SZ_128M - 768 * SZ_1K);
674 test_msg("Failed to free part of bitmap space %d\n", ret);
678 /* Confirm that only those 2 ranges are marked as free. */
679 if (!test_check_exists(cache, SZ_128M + SZ_128K, SZ_128K)) {
680 test_msg("Free space range missing\n");
683 if (!test_check_exists(cache, SZ_128M - 768 * SZ_1K, SZ_256K)) {
684 test_msg("Free space range missing\n");
689 * Confirm that the bitmap range [0, 128Mb - 768Kb[ isn't marked
692 if (test_check_exists(cache, 0, SZ_128M - 768 * SZ_1K)) {
693 test_msg("Bitmap region not removed from space cache\n");
698 * Confirm that the region [128Mb - 512Kb, 128Mb[, which is
699 * covered by the bitmap, isn't marked as free.
701 if (test_check_exists(cache, SZ_128M - SZ_512K, SZ_512K)) {
702 test_msg("Invalid bitmap region marked as free\n");
707 * Now lets mark the region [128Mb - 512Kb, 128Mb[ as free too. But,
708 * lets make sure the free space cache marks it as free in the bitmap,
709 * and doesn't insert a new extent entry to represent this region.
711 ret = btrfs_add_free_space(cache, SZ_128M - SZ_512K, SZ_512K);
713 test_msg("Error adding free space: %d\n", ret);
716 /* Confirm the region is marked as free. */
717 if (!test_check_exists(cache, SZ_128M - SZ_512K, SZ_512K)) {
718 test_msg("Bitmap region not marked as free\n");
723 * Confirm that no new extent entries or bitmap entries were added to
724 * the cache after adding that free space region.
726 ret = check_num_extents_and_bitmaps(cache, 2, 1);
731 * Now lets add a small free space region to the left of the previous
732 * one, which is not contiguous with it and is part of the bitmap too.
733 * The goal is to test that the bitmap entry space stealing doesn't
734 * steal this space region.
736 ret = btrfs_add_free_space(cache, SZ_32M, 8192);
738 test_msg("Error adding free space: %d\n", ret);
743 * Now mark the region [128Mb, 128Mb + 128Kb[ as free too. This will
744 * expand the range covered by the existing extent entry that represents
745 * the free space [128Mb + 128Kb, 128Mb + 256Kb[.
747 ret = btrfs_add_free_space(cache, SZ_128M, SZ_128K);
749 test_msg("Error adding free space: %d\n", ret);
752 /* Confirm the region is marked as free. */
753 if (!test_check_exists(cache, SZ_128M, SZ_128K)) {
754 test_msg("Extent region not marked as free\n");
759 * Confirm that our extent entry didn't stole all free space from the
760 * bitmap, because of the small 8Kb free space region.
762 ret = check_num_extents_and_bitmaps(cache, 2, 1);
767 * So now we have the range [128Mb - 768Kb, 128Mb + 256Kb[ as free
768 * space. Without stealing bitmap free space into extent entry space,
769 * we would have all this free space represented by 2 entries in the
772 * extent entry covering range: [128Mb, 128Mb + 256Kb[
773 * bitmap entry covering range: [128Mb - 768Kb, 128Mb[
775 * Attempting to allocate the whole free space (1Mb) would fail, because
776 * we can't allocate from multiple entries.
777 * With the bitmap free space stealing, we get a single extent entry
778 * that represents the 1Mb free space, and therefore we're able to
779 * allocate the whole free space at once.
781 if (!test_check_exists(cache, SZ_128M - 768 * SZ_1K, SZ_1M)) {
782 test_msg("Expected region not marked as free\n");
786 if (cache->free_space_ctl->free_space != (SZ_1M + 8192)) {
787 test_msg("Cache free space is not 1Mb + 8Kb\n");
791 offset = btrfs_find_space_for_alloc(cache, 0, SZ_1M, 0,
793 if (offset != (SZ_128M - 768 * SZ_1K)) {
794 test_msg("Failed to allocate 1Mb from space cache, returned offset is: %llu\n",
799 /* All that remains is a 8Kb free space region in a bitmap. Confirm. */
800 ret = check_num_extents_and_bitmaps(cache, 1, 1);
804 if (cache->free_space_ctl->free_space != 8192) {
805 test_msg("Cache free space is not 8Kb\n");
809 offset = btrfs_find_space_for_alloc(cache,
812 if (offset != SZ_32M) {
813 test_msg("Failed to allocate 8Kb from space cache, returned offset is: %llu\n",
818 ret = check_cache_empty(cache);
822 cache->free_space_ctl->op = orig_free_space_ops;
823 __btrfs_remove_free_space_cache(cache->free_space_ctl);
828 int btrfs_test_free_space_cache(void)
830 struct btrfs_block_group_cache *cache;
831 struct btrfs_root *root = NULL;
834 test_msg("Running btrfs free space cache tests\n");
836 cache = btrfs_alloc_dummy_block_group(1024 * 1024 * 1024);
838 test_msg("Couldn't run the tests\n");
842 root = btrfs_alloc_dummy_root();
848 root->fs_info = btrfs_alloc_dummy_fs_info();
852 root->fs_info->extent_root = root;
853 cache->fs_info = root->fs_info;
855 ret = test_extents(cache);
858 ret = test_bitmaps(cache);
861 ret = test_bitmaps_and_extents(cache);
865 ret = test_steal_space_from_bitmap_to_extent(cache);
867 btrfs_free_dummy_block_group(cache);
868 btrfs_free_dummy_root(root);
869 test_msg("Free space cache tests finished\n");