From: Josef Bacik Date: Thu, 12 Apr 2012 20:03:57 +0000 (-0400) Subject: Btrfs: use commit root when loading free space cache X-Git-Tag: v3.4-rc3~11^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d53ba47484ed6245e640ee4bfe9d21e9bfc15765;p=platform%2Fkernel%2Flinux-exynos.git Btrfs: use commit root when loading free space cache A user reported that booting his box up with btrfs root on 3.4 was way slower than on 3.3 because I removed the ideal caching code. It turns out that we don't load the free space cache if we're in a commit for deadlock reasons, but since we're reading the cache and it hasn't changed yet we are safe reading the inode and free space item from the commit root, so do that and remove all of the deadlock checks so we don't unnecessarily skip loading the free space cache. The user reported this fixed the slowness. Thanks, Tested-by: Calvin Walton Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index a2134d8141c1..2b35f8d14bb9 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -529,9 +529,7 @@ static int cache_block_group(struct btrfs_block_group_cache *cache, * allocate blocks for the tree root we can't do the fast caching since * we likely hold important locks. */ - if (trans && (!trans->transaction->in_commit) && - (root && root != root->fs_info->tree_root) && - btrfs_test_opt(root, SPACE_CACHE)) { + if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) { ret = load_free_space_cache(fs_info, cache); spin_lock(&cache->lock); diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c index 054707ed5791..baaa518baaf8 100644 --- a/fs/btrfs/free-space-cache.c +++ b/fs/btrfs/free-space-cache.c @@ -747,13 +747,6 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info, bool matched; u64 used = btrfs_block_group_used(&block_group->item); - /* - * If we're unmounting then just return, since this does a search on the - * normal root and not the commit root and we could deadlock. - */ - if (btrfs_fs_closing(fs_info)) - return 0; - /* * If this block group has been marked to be cleared for one reason or * another then we can't trust the on disk cache, so just return. @@ -768,6 +761,8 @@ int load_free_space_cache(struct btrfs_fs_info *fs_info, path = btrfs_alloc_path(); if (!path) return 0; + path->search_commit_root = 1; + path->skip_locking = 1; inode = lookup_free_space_inode(root, block_group, path); if (IS_ERR(inode)) {