From 9afc66498a0b5f76928f9823b58c55c5dfb06ae5 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 5 May 2020 07:58:20 +0800 Subject: [PATCH] btrfs: block-group: refactor how we read one block group item Structure btrfs_block_group has the following members which are currently read from on-disk block group item and key: - length - from item key - used - flags - from block group item However for incoming skinny block group tree, we are going to read those members from different sources. This patch will refactor such read by: - Don't initialize btrfs_block_group::length at allocation Caller should initialize them manually. Also to avoid possible (well, only two callers) missing initialization, add extra ASSERT() in btrfs_add_block_group_cache(). - Refactor length/used/flags initialization into one function The new function, fill_one_block_group() will handle the initialization of such members. - Use btrfs_block_group::length to replace key::offset Since skinny block group item would have a different meaning for its key offset. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/block-group.c | 47 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c index 1137597fbca5..e9232ba3d7ca 100644 --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -161,6 +161,8 @@ static int btrfs_add_block_group_cache(struct btrfs_fs_info *info, struct rb_node *parent = NULL; struct btrfs_block_group *cache; + ASSERT(block_group->length != 0); + spin_lock(&info->block_group_cache_lock); p = &info->block_group_cache_tree.rb_node; @@ -1771,7 +1773,7 @@ static void link_block_group(struct btrfs_block_group *cache) } static struct btrfs_block_group *btrfs_create_block_group_cache( - struct btrfs_fs_info *fs_info, u64 start, u64 size) + struct btrfs_fs_info *fs_info, u64 start) { struct btrfs_block_group *cache; @@ -1787,7 +1789,6 @@ static struct btrfs_block_group *btrfs_create_block_group_cache( } cache->start = start; - cache->length = size; cache->fs_info = fs_info; cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start); @@ -1867,25 +1868,44 @@ static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info) return ret; } +static int read_block_group_item(struct btrfs_block_group *cache, + struct btrfs_path *path, + const struct btrfs_key *key) +{ + struct extent_buffer *leaf = path->nodes[0]; + struct btrfs_block_group_item bgi; + int slot = path->slots[0]; + + cache->length = key->offset; + + read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot), + sizeof(bgi)); + cache->used = btrfs_stack_block_group_used(&bgi); + cache->flags = btrfs_stack_block_group_flags(&bgi); + + return 0; +} + static int read_one_block_group(struct btrfs_fs_info *info, struct btrfs_path *path, const struct btrfs_key *key, int need_clear) { - struct extent_buffer *leaf = path->nodes[0]; struct btrfs_block_group *cache; struct btrfs_space_info *space_info; - struct btrfs_block_group_item bgi; const bool mixed = btrfs_fs_incompat(info, MIXED_GROUPS); - int slot = path->slots[0]; int ret; ASSERT(key->type == BTRFS_BLOCK_GROUP_ITEM_KEY); - cache = btrfs_create_block_group_cache(info, key->objectid, key->offset); + cache = btrfs_create_block_group_cache(info, key->objectid); if (!cache) return -ENOMEM; + ret = read_block_group_item(cache, path, key); + if (ret < 0) + goto error; + if (need_clear) { /* * When we mount with old space cache, we need to @@ -1900,10 +1920,6 @@ static int read_one_block_group(struct btrfs_fs_info *info, if (btrfs_test_opt(info, SPACE_CACHE)) cache->disk_cache_state = BTRFS_DC_CLEAR; } - read_extent_buffer(leaf, &bgi, btrfs_item_ptr_offset(leaf, slot), - sizeof(bgi)); - cache->used = btrfs_stack_block_group_used(&bgi); - cache->flags = btrfs_stack_block_group_flags(&bgi); if (!mixed && ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) && (cache->flags & BTRFS_BLOCK_GROUP_DATA))) { btrfs_err(info, @@ -1931,15 +1947,15 @@ static int read_one_block_group(struct btrfs_fs_info *info, * are empty, and we can just add all the space in and be done with it. * This saves us _a_lot_ of time, particularly in the full case. */ - if (key->offset == cache->used) { + if (cache->length == cache->used) { cache->last_byte_to_unpin = (u64)-1; cache->cached = BTRFS_CACHE_FINISHED; btrfs_free_excluded_extents(cache); } else if (cache->used == 0) { cache->last_byte_to_unpin = (u64)-1; cache->cached = BTRFS_CACHE_FINISHED; - add_new_free_space(cache, key->objectid, - key->objectid + key->offset); + add_new_free_space(cache, cache->start, + cache->start + cache->length); btrfs_free_excluded_extents(cache); } @@ -1949,7 +1965,7 @@ static int read_one_block_group(struct btrfs_fs_info *info, goto error; } trace_btrfs_add_block_group(info, cache, 0); - btrfs_update_space_info(info, cache->flags, key->offset, + btrfs_update_space_info(info, cache->flags, cache->length, cache->used, cache->bytes_super, &space_info); cache->space_info = space_info; @@ -2096,10 +2112,11 @@ int btrfs_make_block_group(struct btrfs_trans_handle *trans, u64 bytes_used, btrfs_set_log_full_commit(trans); - cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size); + cache = btrfs_create_block_group_cache(fs_info, chunk_offset); if (!cache) return -ENOMEM; + cache->length = size; cache->used = bytes_used; cache->flags = type; cache->last_byte_to_unpin = (u64)-1; -- 2.11.0