From 120d66eec0dcb966fbd03f743598b2ff2513436b Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 9 Nov 2010 14:56:50 +0800 Subject: [PATCH] btrfs: Add a helper try_merge_free_space() When adding a new extent, we'll firstly see if we can merge this extent to the left or/and right extent. Extract this as a helper try_merge_free_space(). As a side effect, we fix a small bug that if the new extent has non-bitmap left entry but is unmergeble, we'll directly link the extent without trying to drop it into bitmap. This also prepares for the next patch. Reviewed-by: Josef Bacik Signed-off-by: Li Zefan --- fs/btrfs/free-space-cache.c | 75 +++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 32 deletions(-) diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 2974c4744d5c..cf67dc3b7bf8 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -1363,22 +1363,14 @@ out: return ret; } -int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, - u64 offset, u64 bytes) +bool try_merge_free_space(struct btrfs_block_group_cache *block_group, + struct btrfs_free_space *info) { - struct btrfs_free_space *right_info = NULL; - struct btrfs_free_space *left_info = NULL; - struct btrfs_free_space *info = NULL; - int ret = 0; - - info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); - if (!info) - return -ENOMEM; - - info->offset = offset; - info->bytes = bytes; - - spin_lock(&block_group->tree_lock); + struct btrfs_free_space *left_info; + struct btrfs_free_space *right_info; + bool merged = false; + u64 offset = info->offset; + u64 bytes = info->bytes; /* * first we want to see if there is free space adjacent to the range we @@ -1392,27 +1384,11 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, else left_info = tree_search_offset(block_group, offset - 1, 0, 0); - /* - * If there was no extent directly to the left or right of this new - * extent then we know we're going to have to allocate a new extent, so - * before we do that see if we need to drop this into a bitmap - */ - if ((!left_info || left_info->bitmap) && - (!right_info || right_info->bitmap)) { - ret = insert_into_bitmap(block_group, info); - - if (ret < 0) { - goto out; - } else if (ret) { - ret = 0; - goto out; - } - } - if (right_info && !right_info->bitmap) { unlink_free_space(block_group, right_info); info->bytes += right_info->bytes; kfree(right_info); + merged = true; } if (left_info && !left_info->bitmap && @@ -1421,8 +1397,43 @@ int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, info->offset = left_info->offset; info->bytes += left_info->bytes; kfree(left_info); + merged = true; } + return merged; +} + +int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, + u64 offset, u64 bytes) +{ + struct btrfs_free_space *info; + int ret = 0; + + info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); + if (!info) + return -ENOMEM; + + info->offset = offset; + info->bytes = bytes; + + spin_lock(&block_group->tree_lock); + + if (try_merge_free_space(block_group, info)) + goto link; + + /* + * There was no extent directly to the left or right of this new + * extent then we know we're going to have to allocate a new extent, so + * before we do that see if we need to drop this into a bitmap + */ + ret = insert_into_bitmap(block_group, info); + if (ret < 0) { + goto out; + } else if (ret) { + ret = 0; + goto out; + } +link: ret = link_free_space(block_group, info); if (ret) kfree(info); -- 2.20.1