diff --git a/fs/btrfs/Kconfig b/fs/btrfs/Kconfig
index 9a8622a5b867..d5bfcb744fe5 100644
--- a/fs/btrfs/Kconfig
+++ b/fs/btrfs/Kconfig
@@ -52,3 +52,14 @@ config BTRFS_FS_CHECK_INTEGRITY
In most cases, unless you are a btrfs developer who needs
to verify the integrity of (super)-block write requests
during the run of a regression test, say N
+
+config BTRFS_FS_RUN_SANITY_TESTS
+ bool "Btrfs will run sanity tests upon loading"
+ depends on BTRFS_FS
+ help
+ This will run some basic sanity tests on the free space cache
+ code to make sure it is acting as it should. These are mostly
+ regression tests and are only really interesting to btrfs devlopers.
+
+ If unsure, say N.
+
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 1f84fc09c1a8..1d80afa6d3db 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2967,3 +2967,522 @@ int btrfs_write_out_ino_cache(struct btrfs_root *root,
iput(inode);
return ret;
}
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+static struct btrfs_block_group_cache *init_test_block_group(void)
+{
+ struct btrfs_block_group_cache *cache;
+
+ cache = kzalloc(sizeof(*cache), GFP_NOFS);
+ if (!cache)
+ return NULL;
+ cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
+ GFP_NOFS);
+ if (!cache->free_space_ctl) {
+ kfree(cache);
+ return NULL;
+ }
+
+ cache->key.objectid = 0;
+ cache->key.offset = 1024 * 1024 * 1024;
+ cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
+ cache->sectorsize = 4096;
+
+ spin_lock_init(&cache->lock);
+ INIT_LIST_HEAD(&cache->list);
+ INIT_LIST_HEAD(&cache->cluster_list);
+ INIT_LIST_HEAD(&cache->new_bg_list);
+
+ btrfs_init_free_space_ctl(cache);
+
+ return cache;
+}
+
+/*
+ * Checks to see if the given range is in the free space cache. This is really
+ * just used to check the absence of space, so if there is free space in the
+ * range at all we will return 1.
+ */
+static int check_exists(struct btrfs_block_group_cache *cache, u64 offset,
+ u64 bytes)
+{
+ struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
+ struct btrfs_free_space *info;
+ int ret = 0;
+
+ spin_lock(&ctl->tree_lock);
+ info = tree_search_offset(ctl, offset, 0, 0);
+ if (!info) {
+ info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
+ 1, 0);
+ if (!info)
+ goto out;
+ }
+
+have_info:
+ if (info->bitmap) {
+ u64 bit_off, bit_bytes;
+ struct rb_node *n;
+ struct btrfs_free_space *tmp;
+
+ bit_off = offset;
+ bit_bytes = ctl->unit;
+ ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
+ if (!ret) {
+ if (bit_off == offset) {
+ ret = 1;
+ goto out;
+ } else if (bit_off > offset &&
+ offset + bytes > bit_off) {
+ ret = 1;
+ goto out;
+ }
+ }
+
+ n = rb_prev(&info->offset_index);
+ while (n) {
+ tmp = rb_entry(n, struct btrfs_free_space,
+ offset_index);
+ if (tmp->offset + tmp->bytes < offset)
+ break;
+ if (offset + bytes < tmp->offset) {
+ n = rb_prev(&info->offset_index);
+ continue;
+ }
+ info = tmp;
+ goto have_info;
+ }
+
+ n = rb_next(&info->offset_index);
+ while (n) {
+ tmp = rb_entry(n, struct btrfs_free_space,
+ offset_index);
+ if (offset + bytes < tmp->offset)
+ break;
+ if (tmp->offset + tmp->bytes < offset) {
+ n = rb_next(&info->offset_index);
+ continue;
+ }
+ info = tmp;
+ goto have_info;
+ }
+
+ goto out;
+ }
+
+ if (info->offset == offset) {
+ ret = 1;
+ goto out;
+ }
+
+ if (offset > info->offset && offset < info->offset + info->bytes)
+ ret = 1;
+out:
+ spin_unlock(&ctl->tree_lock);
+ return ret;
+}
+
+/*
+ * Use this if you need to make a bitmap or extent entry specifically, it
+ * doesn't do any of the merging that add_free_space does, this acts a lot like
+ * how the free space cache loading stuff works, so you can get really weird
+ * configurations.
+ */
+static int add_free_space_entry(struct btrfs_block_group_cache *cache,
+ u64 offset, u64 bytes, bool bitmap)
+{
+ struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
+ struct btrfs_free_space *info = NULL, *bitmap_info;
+ void *map = NULL;
+ u64 bytes_added;
+ int ret;
+
+again:
+ if (!info) {
+ info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
+ if (!info)
+ return -ENOMEM;
+ }
+
+ if (!bitmap) {
+ spin_lock(&ctl->tree_lock);
+ info->offset = offset;
+ info->bytes = bytes;
+ ret = link_free_space(ctl, info);
+ spin_unlock(&ctl->tree_lock);
+ if (ret)
+ kmem_cache_free(btrfs_free_space_cachep, info);
+ return ret;
+ }
+
+ if (!map) {
+ map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
+ if (!map) {
+ kmem_cache_free(btrfs_free_space_cachep, info);
+ return -ENOMEM;
+ }
+ }
+
+ spin_lock(&ctl->tree_lock);
+ bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
+ 1, 0);
+ if (!bitmap_info) {
+ info->bitmap = map;
+ map = NULL;
+ add_new_bitmap(ctl, info, offset);
+ bitmap_info = info;
+ }
+
+ bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
+ bytes -= bytes_added;
+ offset += bytes_added;
+ spin_unlock(&ctl->tree_lock);
+
+ if (bytes)
+ goto again;
+
+ if (map)
+ kfree(map);
+ return 0;
+}
+
+/*
+ * This test just does basic sanity checking, making sure we can add an exten
+ * entry and remove space from either end and the middle, and make sure we can
+ * remove space that covers adjacent extent entries.
+ */
+static int test_extents(struct btrfs_block_group_cache *cache)
+{
+ int ret = 0;
+
+ printk(KERN_ERR "Running extent only tests\n");
+
+ /* First just make sure we can remove an entire entry */
+ ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error adding initial extents %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error removing extent %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 0, 4 * 1024 * 1024)) {
+ printk(KERN_ERR "Full remove left some lingering space\n");
+ return -1;
+ }
+
+ /* Ok edge and middle cases now */
+ ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error adding half extent %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 1 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error removing tail end %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error removing front end %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 2 * 1024 * 1024, 4096);
+ if (ret) {
+ printk(KERN_ERR "Error removing middle peice %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 0, 1 * 1024 * 1024)) {
+ printk(KERN_ERR "Still have space at the front\n");
+ return -1;
+ }
+
+ if (check_exists(cache, 2 * 1024 * 1024, 4096)) {
+ printk(KERN_ERR "Still have space in the middle\n");
+ return -1;
+ }
+
+ if (check_exists(cache, 3 * 1024 * 1024, 1 * 1024 * 1024)) {
+ printk(KERN_ERR "Still have space at the end\n");
+ return -1;
+ }
+
+ /* Cleanup */
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+ return 0;
+}
+
+static int test_bitmaps(struct btrfs_block_group_cache *cache)
+{
+ u64 next_bitmap_offset;
+ int ret;
+
+ printk(KERN_ERR "Running bitmap only tests\n");
+
+ ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't create a bitmap entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error removing bitmap full range %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 0, 4 * 1024 * 1024)) {
+ printk(KERN_ERR "Left some space in bitmap\n");
+ return -1;
+ }
+
+ ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add to our bitmap entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 2 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Couldn't remove middle chunk %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * The first bitmap we have starts at offset 0 so the next one is just
+ * at the end of the first bitmap.
+ */
+ next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
+
+ /* Test a bit straddling two bitmaps */
+ ret = add_free_space_entry(cache, next_bitmap_offset -
+ (2 * 1024 * 1024), 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add space that straddles two bitmaps"
+ " %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, next_bitmap_offset -
+ (1 * 1024 * 1024), 2 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, next_bitmap_offset - (1 * 1024 * 1024),
+ 2 * 1024 * 1024)) {
+ printk(KERN_ERR "Left some space when removing overlapping\n");
+ return -1;
+ }
+
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+ return 0;
+}
+
+/* This is the high grade jackassery */
+static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
+{
+ u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
+ int ret;
+
+ printk(KERN_ERR "Running bitmap and extent tests\n");
+
+ /*
+ * First let's do something simple, an extent at the same offset as the
+ * bitmap, but the free space completely in the extent and then
+ * completely in the bitmap.
+ */
+ ret = add_free_space_entry(cache, 4 * 1024 * 1024, 1 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't create bitmap entry %d\n", ret);
+ return ret;
+ }
+
+ ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Couldn't remove extent entry %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 0, 1 * 1024 * 1024)) {
+ printk(KERN_ERR "Left remnants after our remove\n");
+ return -1;
+ }
+
+ /* Now to add back the extent entry and remove from the bitmap */
+ ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
+ if (ret) {
+ printk(KERN_ERR "Couldn't re-add extent entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 4 * 1024 * 1024, 1 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Couldn't remove from bitmap %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 4 * 1024 * 1024, 1 * 1024 * 1024)) {
+ printk(KERN_ERR "Left remnants in the bitmap\n");
+ return -1;
+ }
+
+ /*
+ * Ok so a little more evil, extent entry and bitmap at the same offset,
+ * removing an overlapping chunk.
+ */
+ ret = add_free_space_entry(cache, 1 * 1024 * 1024, 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add to a bitmap %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 512 * 1024, 3 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Couldn't remove overlapping space %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 512 * 1024, 3 * 1024 * 1024)) {
+ printk(KERN_ERR "Left over peices after removing "
+ "overlapping\n");
+ return -1;
+ }
+
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+ /* Now with the extent entry offset into the bitmap */
+ ret = add_free_space_entry(cache, 4 * 1024 * 1024, 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add space to the bitmap %d\n", ret);
+ return ret;
+ }
+
+ ret = add_free_space_entry(cache, 2 * 1024 * 1024, 2 * 1024 * 1024, 0);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add extent to the cache %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 4 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Problem removing overlapping space %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, 3 * 1024 * 1024, 4 * 1024 * 1024)) {
+ printk(KERN_ERR "Left something behind when removing space");
+ return -1;
+ }
+
+ /*
+ * This has blown up in the past, the extent entry starts before the
+ * bitmap entry, but we're trying to remove an offset that falls
+ * completely within the bitmap range and is in both the extent entry
+ * and the bitmap entry, looks like this
+ *
+ * [ extent ]
+ * [ bitmap ]
+ * [ del ]
+ */
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+ ret = add_free_space_entry(cache, bitmap_offset + 4 * 1024 * 1024,
+ 4 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add bitmap %d\n", ret);
+ return ret;
+ }
+
+ ret = add_free_space_entry(cache, bitmap_offset - 1 * 1024 * 1024,
+ 5 * 1024 * 1024, 0);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, bitmap_offset + 1 * 1024 * 1024,
+ 5 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Failed to free our space %d\n", ret);
+ return ret;
+ }
+
+ if (check_exists(cache, bitmap_offset + 1 * 1024 * 1024,
+ 5 * 1024 * 1024)) {
+ printk(KERN_ERR "Left stuff over\n");
+ return -1;
+ }
+
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+
+ /*
+ * This blew up before, we have part of the free space in a bitmap and
+ * then the entirety of the rest of the space in an extent. This used
+ * to return -EAGAIN back from btrfs_remove_extent, make sure this
+ * doesn't happen.
+ */
+ ret = add_free_space_entry(cache, 1 * 1024 * 1024, 2 * 1024 * 1024, 1);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add bitmap entry %d\n", ret);
+ return ret;
+ }
+
+ ret = add_free_space_entry(cache, 3 * 1024 * 1024, 1 * 1024 * 1024, 0);
+ if (ret) {
+ printk(KERN_ERR "Couldn't add extent entry %d\n", ret);
+ return ret;
+ }
+
+ ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 3 * 1024 * 1024);
+ if (ret) {
+ printk(KERN_ERR "Error removing bitmap and extent "
+ "overlapping %d\n", ret);
+ return ret;
+ }
+
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+ return 0;
+}
+
+void btrfs_test_free_space_cache(void)
+{
+ struct btrfs_block_group_cache *cache;
+
+ printk(KERN_ERR "Running btrfs free space cache tests\n");
+
+ cache = init_test_block_group();
+ if (!cache) {
+ printk(KERN_ERR "Couldn't run the tests\n");
+ return;
+ }
+
+ if (test_extents(cache))
+ goto out;
+ if (test_bitmaps(cache))
+ goto out;
+ if (test_bitmaps_and_extents(cache))
+ goto out;
+out:
+ __btrfs_remove_free_space_cache(cache->free_space_ctl);
+ kfree(cache->free_space_ctl);
+ kfree(cache);
+ printk(KERN_ERR "Free space cache tests finished\n");
+}
+#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index 8f2613f779ed..4dc17d8809c7 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -110,4 +110,9 @@ int btrfs_return_cluster_to_free_space(
struct btrfs_free_cluster *cluster);
int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
u64 *trimmed, u64 start, u64 end, u64 minlen);
+
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+void btrfs_test_free_space_cache(void);
+#endif
+
#endif
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index f6b88595f858..714ae479de2e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -56,6 +56,7 @@
#include "compression.h"
#include "rcu-string.h"
#include "dev-replace.h"
+#include "free-space-cache.h"
#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>
@@ -1739,6 +1740,10 @@ static int __init init_btrfs_fs(void)
btrfs_init_lockdep();
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+ btrfs_test_free_space_cache();
+#endif
+
printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
return 0;