From b8399dee478db7939cd0d6fda8ecacddf2facd03 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 8 Dec 2010 09:15:11 -0500 Subject: Btrfs: do not do fast caching if we are allocating blocks for tree_root Since the fast caching uses normal tree locking, we can possibly deadlock if we get to the caching via a btrfs_search_slot() on the tree_root. So just check to see if the root we are on is the tree root, and just don't do the fast caching. Reported-by: Sage Weil Signed-off-by: Josef Bacik --- fs/btrfs/extent-tree.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'fs/btrfs') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 8c56f5b3894..cec05e10014 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -429,6 +429,7 @@ err: static int cache_block_group(struct btrfs_block_group_cache *cache, struct btrfs_trans_handle *trans, + struct btrfs_root *root, int load_cache_only) { struct btrfs_fs_info *fs_info = cache->fs_info; @@ -442,9 +443,12 @@ static int cache_block_group(struct btrfs_block_group_cache *cache, /* * We can't do the read from on-disk cache during a commit since we need - * to have the normal tree locking. + * to have the normal tree locking. Also if we are currently trying to + * allocate blocks for the tree root we can't do the fast caching since + * we likely hold important locks. */ - if (!trans->transaction->in_commit) { + if (!trans->transaction->in_commit && + (root && root != root->fs_info->tree_root)) { spin_lock(&cache->lock); if (cache->cached != BTRFS_CACHE_NO) { spin_unlock(&cache->lock); @@ -4083,7 +4087,7 @@ static int update_block_group(struct btrfs_trans_handle *trans, * space back to the block group, otherwise we will leak space. */ if (!alloc && cache->cached == BTRFS_CACHE_NO) - cache_block_group(cache, trans, 1); + cache_block_group(cache, trans, NULL, 1); byte_in_group = bytenr - cache->key.objectid; WARN_ON(byte_in_group > cache->key.offset); @@ -4937,7 +4941,8 @@ have_block_group: if (unlikely(block_group->cached == BTRFS_CACHE_NO)) { u64 free_percent; - ret = cache_block_group(block_group, trans, 1); + ret = cache_block_group(block_group, trans, + orig_root, 1); if (block_group->cached == BTRFS_CACHE_FINISHED) goto have_block_group; @@ -4961,7 +4966,8 @@ have_block_group: if (loop > LOOP_CACHING_NOWAIT || (loop > LOOP_FIND_IDEAL && atomic_read(&space_info->caching_threads) < 2)) { - ret = cache_block_group(block_group, trans, 0); + ret = cache_block_group(block_group, trans, + orig_root, 0); BUG_ON(ret); } found_uncached_bg = true; @@ -5518,7 +5524,7 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans, u64 num_bytes = ins->offset; block_group = btrfs_lookup_block_group(root->fs_info, ins->objectid); - cache_block_group(block_group, trans, 0); + cache_block_group(block_group, trans, NULL, 0); caching_ctl = get_caching_control(block_group); if (!caching_ctl) { -- cgit v1.2.3-70-g09d2