From 45b8c9a8b1e15bf79c2c17ec217adf96785f8011 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 30 Sep 2008 14:40:06 -0400 Subject: [PATCH] Btrfs: fix seekiness due to finding the wrong block group This patch fixes a problem where we end up seeking too much when *last_ptr is valid. This happens because btrfs_lookup_first_block_group only returns a block group that starts on or after the given search start, so if the search_start is in the middle of a block group it will return the block group after the given search_start, which is suboptimal. This patch fixes that by doing a btrfs_lookup_block_group, which will return the block group that contains the given search start. If we fail to find a block group, we fall back on btrfs_lookup_first_block_group so we can find the next block group, not sure if this is absolutely needed, but better safe than sorry. Also if we can't find the block group that we need, or it happens to not be of the right type, we need to add empty_cluster since *last_ptr could point to a mismatched block group, which means we need to start over with empty_cluster added to total needed. Thank you, Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 8043b9d584a..64e14ddf623 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -2238,7 +2238,10 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, total_needed += empty_size; new_group: - block_group = btrfs_lookup_first_block_group(info, search_start); + block_group = btrfs_lookup_block_group(info, search_start); + if (!block_group) + block_group = btrfs_lookup_first_block_group(info, + search_start); /* * Ok this looks a little tricky, buts its really simple. First if we @@ -2255,8 +2258,10 @@ new_group: if (!block_group || (!block_group_bits(block_group, data) && last_ptr && *last_ptr)) { if (search_start != orig_search_start) { - if (last_ptr && *last_ptr) + if (last_ptr && *last_ptr) { + total_needed += empty_cluster; *last_ptr = 0; + } search_start = orig_search_start; goto new_group; } else if (!chunk_alloc_done && allowed_chunk_alloc) { -- 2.39.3