From 0af3d00bad38d3bb9912a60928ad0669f17bdb76 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 21 Jun 2010 14:48:16 -0400 Subject: Btrfs: create special free space cache inode In order to save free space cache, we need an inode to hold the data, and we need a special item to point at the right inode for the right block group. So first, create a special item that will point to the right inode, and the number of extent entries we will have and the number of bitmaps we will have. We truncate and pre-allocate space everytime to make sure it's uptodate. This feature will be turned on as soon as you mount with -o space_cache, however it is safe to boot into old kernels, they will just generate the cache the old fashion way. When you boot back into a newer kernel we will notice that we modified and not the cache and automatically discard the cache. Signed-off-by: Josef Bacik --- fs/btrfs/extent-tree.c | 231 +++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 225 insertions(+), 6 deletions(-) (limited to 'fs/btrfs/extent-tree.c') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 32d094002a57..aab40fb3faed 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2688,6 +2688,109 @@ next_block_group(struct btrfs_root *root, return cache; } +static int cache_save_setup(struct btrfs_block_group_cache *block_group, + struct btrfs_trans_handle *trans, + struct btrfs_path *path) +{ + struct btrfs_root *root = block_group->fs_info->tree_root; + struct inode *inode = NULL; + u64 alloc_hint = 0; + int num_pages = 0; + int retries = 0; + int ret = 0; + + /* + * If this block group is smaller than 100 megs don't bother caching the + * block group. + */ + if (block_group->key.offset < (100 * 1024 * 1024)) { + spin_lock(&block_group->lock); + block_group->disk_cache_state = BTRFS_DC_WRITTEN; + spin_unlock(&block_group->lock); + return 0; + } + +again: + inode = lookup_free_space_inode(root, block_group, path); + if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) { + ret = PTR_ERR(inode); + btrfs_release_path(root, path); + goto out; + } + + if (IS_ERR(inode)) { + BUG_ON(retries); + retries++; + + if (block_group->ro) + goto out_free; + + ret = create_free_space_inode(root, trans, block_group, path); + if (ret) + goto out_free; + goto again; + } + + /* + * We want to set the generation to 0, that way if anything goes wrong + * from here on out we know not to trust this cache when we load up next + * time. + */ + BTRFS_I(inode)->generation = 0; + ret = btrfs_update_inode(trans, root, inode); + WARN_ON(ret); + + if (i_size_read(inode) > 0) { + ret = btrfs_truncate_free_space_cache(root, trans, path, + inode); + if (ret) + goto out_put; + } + + spin_lock(&block_group->lock); + if (block_group->cached != BTRFS_CACHE_FINISHED) { + spin_unlock(&block_group->lock); + goto out_put; + } + spin_unlock(&block_group->lock); + + num_pages = (int)div64_u64(block_group->key.offset, 1024 * 1024 * 1024); + if (!num_pages) + num_pages = 1; + + /* + * Just to make absolutely sure we have enough space, we're going to + * preallocate 12 pages worth of space for each block group. In + * practice we ought to use at most 8, but we need extra space so we can + * add our header and have a terminator between the extents and the + * bitmaps. + */ + num_pages *= 16; + num_pages *= PAGE_CACHE_SIZE; + + ret = btrfs_check_data_free_space(inode, num_pages); + if (ret) + goto out_put; + + ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages, + num_pages, num_pages, + &alloc_hint); + btrfs_free_reserved_data_space(inode, num_pages); +out_put: + iput(inode); +out_free: + btrfs_release_path(root, path); +out: + spin_lock(&block_group->lock); + if (ret) + block_group->disk_cache_state = BTRFS_DC_ERROR; + else + block_group->disk_cache_state = BTRFS_DC_SETUP; + spin_unlock(&block_group->lock); + + return ret; +} + int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans, struct btrfs_root *root) { @@ -2700,6 +2803,25 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans, if (!path) return -ENOMEM; +again: + while (1) { + cache = btrfs_lookup_first_block_group(root->fs_info, last); + while (cache) { + if (cache->disk_cache_state == BTRFS_DC_CLEAR) + break; + cache = next_block_group(root, cache); + } + if (!cache) { + if (last == 0) + break; + last = 0; + continue; + } + err = cache_save_setup(cache, trans, path); + last = cache->key.objectid + cache->key.offset; + btrfs_put_block_group(cache); + } + while (1) { if (last == 0) { err = btrfs_run_delayed_refs(trans, root, @@ -2709,6 +2831,11 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans, cache = btrfs_lookup_first_block_group(root->fs_info, last); while (cache) { + if (cache->disk_cache_state == BTRFS_DC_CLEAR) { + btrfs_put_block_group(cache); + goto again; + } + if (cache->dirty) break; cache = next_block_group(root, cache); @@ -2883,11 +3010,16 @@ int btrfs_check_data_free_space(struct inode *inode, u64 bytes) struct btrfs_space_info *data_sinfo; struct btrfs_root *root = BTRFS_I(inode)->root; u64 used; - int ret = 0, committed = 0; + int ret = 0, committed = 0, alloc_chunk = 1; /* make sure bytes are sectorsize aligned */ bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1); + if (root == root->fs_info->tree_root) { + alloc_chunk = 0; + committed = 1; + } + data_sinfo = BTRFS_I(inode)->space_info; if (!data_sinfo) goto alloc; @@ -2906,7 +3038,7 @@ again: * if we don't have enough free bytes in this space then we need * to alloc a new chunk. */ - if (!data_sinfo->full) { + if (!data_sinfo->full && alloc_chunk) { u64 alloc_target; data_sinfo->force_alloc = 1; @@ -3777,12 +3909,12 @@ static int update_block_group(struct btrfs_trans_handle *trans, struct btrfs_root *root, u64 bytenr, u64 num_bytes, int alloc) { - struct btrfs_block_group_cache *cache; + struct btrfs_block_group_cache *cache = NULL; struct btrfs_fs_info *info = root->fs_info; - int factor; u64 total = num_bytes; u64 old_val; u64 byte_in_group; + int factor; /* block accounting for super block */ spin_lock(&info->delalloc_lock); @@ -3804,11 +3936,17 @@ static int update_block_group(struct btrfs_trans_handle *trans, factor = 2; else factor = 1; + byte_in_group = bytenr - cache->key.objectid; WARN_ON(byte_in_group > cache->key.offset); spin_lock(&cache->space_info->lock); spin_lock(&cache->lock); + + if (btrfs_super_cache_generation(&info->super_copy) != 0 && + cache->disk_cache_state < BTRFS_DC_CLEAR) + cache->disk_cache_state = BTRFS_DC_CLEAR; + cache->dirty = 1; old_val = btrfs_block_group_used(&cache->item); num_bytes = min(total, cache->key.offset - byte_in_group); @@ -7814,6 +7952,40 @@ out: return ret; } +void btrfs_put_block_group_cache(struct btrfs_fs_info *info) +{ + struct btrfs_block_group_cache *block_group; + u64 last = 0; + + while (1) { + struct inode *inode; + + block_group = btrfs_lookup_first_block_group(info, last); + while (block_group) { + spin_lock(&block_group->lock); + if (block_group->iref) + break; + spin_unlock(&block_group->lock); + block_group = next_block_group(info->tree_root, + block_group); + } + if (!block_group) { + if (last == 0) + break; + last = 0; + continue; + } + + inode = block_group->inode; + block_group->iref = 0; + block_group->inode = NULL; + spin_unlock(&block_group->lock); + iput(inode); + last = block_group->key.objectid + block_group->key.offset; + btrfs_put_block_group(block_group); + } +} + int btrfs_free_block_groups(struct btrfs_fs_info *info) { struct btrfs_block_group_cache *block_group; @@ -7897,6 +8069,8 @@ int btrfs_read_block_groups(struct btrfs_root *root) struct btrfs_key key; struct btrfs_key found_key; struct extent_buffer *leaf; + int need_clear = 0; + u64 cache_gen; root = info->extent_root; key.objectid = 0; @@ -7906,6 +8080,11 @@ int btrfs_read_block_groups(struct btrfs_root *root) if (!path) return -ENOMEM; + cache_gen = btrfs_super_cache_generation(&root->fs_info->super_copy); + if (cache_gen != 0 && + btrfs_super_generation(&root->fs_info->super_copy) != cache_gen) + need_clear = 1; + while (1) { ret = find_first_block_group(root, path, &key); if (ret > 0) @@ -7928,6 +8107,9 @@ int btrfs_read_block_groups(struct btrfs_root *root) INIT_LIST_HEAD(&cache->list); INIT_LIST_HEAD(&cache->cluster_list); + if (need_clear) + cache->disk_cache_state = BTRFS_DC_CLEAR; + /* * we only want to have 32k of ram per block group for keeping * track of free space, and if we pass 1/2 of that we want to @@ -8032,6 +8214,7 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, cache->key.offset = size; cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY; cache->sectorsize = root->sectorsize; + cache->fs_info = root->fs_info; /* * we only want to have 32k of ram per block group for keeping track @@ -8088,7 +8271,9 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, struct btrfs_path *path; struct btrfs_block_group_cache *block_group; struct btrfs_free_cluster *cluster; + struct btrfs_root *tree_root = root->fs_info->tree_root; struct btrfs_key key; + struct inode *inode; int ret; root = root->fs_info->extent_root; @@ -8097,8 +8282,6 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, BUG_ON(!block_group); BUG_ON(!block_group->ro); - memcpy(&key, &block_group->key, sizeof(key)); - /* make sure this block group isn't part of an allocation cluster */ cluster = &root->fs_info->data_alloc_cluster; spin_lock(&cluster->refill_lock); @@ -8117,6 +8300,40 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, path = btrfs_alloc_path(); BUG_ON(!path); + inode = lookup_free_space_inode(root, block_group, path); + if (!IS_ERR(inode)) { + btrfs_orphan_add(trans, inode); + clear_nlink(inode); + /* One for the block groups ref */ + spin_lock(&block_group->lock); + if (block_group->iref) { + block_group->iref = 0; + block_group->inode = NULL; + spin_unlock(&block_group->lock); + iput(inode); + } else { + spin_unlock(&block_group->lock); + } + /* One for our lookup ref */ + iput(inode); + } + + key.objectid = BTRFS_FREE_SPACE_OBJECTID; + key.offset = block_group->key.objectid; + key.type = 0; + + ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1); + if (ret < 0) + goto out; + if (ret > 0) + btrfs_release_path(tree_root, path); + if (ret == 0) { + ret = btrfs_del_item(trans, tree_root, path); + if (ret) + goto out; + btrfs_release_path(tree_root, path); + } + spin_lock(&root->fs_info->block_group_cache_lock); rb_erase(&block_group->cache_node, &root->fs_info->block_group_cache_tree); @@ -8140,6 +8357,8 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans, block_group->space_info->bytes_readonly -= block_group->key.offset; spin_unlock(&block_group->space_info->lock); + memcpy(&key, &block_group->key, sizeof(key)); + btrfs_clear_space_info_full(root->fs_info); btrfs_put_block_group(block_group); -- cgit v1.2.1