1 files changed, 519 insertions, 0 deletions

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 */