From f5a31e166772a7b9fff6725b697eb8b57633671e Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 10 Nov 2008 11:47:09 -0500 Subject: Btrfs: Try harder while searching for free space The loop searching for free space would exit out too soon when metadata clustering was trying to allocate a large extent. This makes sure a full scan of the free space is done searching for only the minimum extent size requested by the higher layers. Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 38 ++++++++++++++++++++++++++++++-------- 1 file changed, 30 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 2451717d36d..55d6a66c622 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2123,6 +2123,7 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, int allowed_chunk_alloc = 0; struct list_head *head = NULL, *cur = NULL; int loop = 0; + int extra_loop = 0; struct btrfs_space_info *space_info; WARN_ON(num_bytes < root->sectorsize); @@ -2191,6 +2192,9 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, free_space = btrfs_find_free_space(block_group, search_start, total_needed); + if (empty_size) + extra_loop = 1; + if (free_space) { u64 start = block_group->key.objectid; u64 end = block_group->key.objectid + @@ -2254,11 +2258,11 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, new_group: mutex_unlock(&block_group->alloc_mutex); new_group_no_lock: + /* don't try to compare new allocations against the + * last allocation any more + */ last_wanted = 0; - if (!allowed_chunk_alloc) { - total_needed -= empty_size; - empty_size = 0; - } + /* * Here's how this works. * loop == 0: we were searching a block group via a hint @@ -2276,9 +2280,21 @@ new_group_no_lock: cur = head->next; loop++; } else if (loop == 1 && cur == head) { - + int keep_going; + + /* at this point we give up on the empty_size + * allocations and just try to allocate the min + * space. + * + * The extra_loop field was set if an empty_size + * allocation was attempted above, and if this + * is try we need to try the loop again without + * the additional empty_size. + */ total_needed -= empty_size; empty_size = 0; + keep_going = extra_loop; + loop++; if (allowed_chunk_alloc && !chunk_alloc_done) { up_read(&space_info->groups_sem); @@ -2287,13 +2303,19 @@ new_group_no_lock: if (ret < 0) break; down_read(&space_info->groups_sem); - loop++; head = &space_info->block_groups; - cur = head->next; + /* + * we've allocated a new chunk, keep + * trying + */ + keep_going = 1; chunk_alloc_done = 1; } else if (!allowed_chunk_alloc) { space_info->force_alloc = 1; - break; + } + if (keep_going) { + cur = head->next; + extra_loop = 0; } else { break; } -- cgit v1.2.3