From aee68ee5f5427b91be5b23459993134ca64ecf00 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 13 Jun 2013 13:50:23 -0400 Subject: [PATCH] Btrfs: fix not being able to find skinny extents during relocate We unconditionally search for the EXTENT_ITEM_KEY for metadata during balance, and then check the key that we found to see if it is actually a METADATA_ITEM_KEY, but this doesn't work right because METADATA is a higher key value, so if what we are looking for happens to be the first item in the leaf the search will dump us out at the previous leaf, and we won't find our item. So instead do what we do everywhere else, search for the skinny extent first and if we don't find it go back and re-search for the extent item. This patch fixes the panic I was hitting when balancing a large file system with skinny extents. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/relocation.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 4a404b44b0ad..d91f106df665 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3309,6 +3309,8 @@ static int __add_tree_block(struct reloc_control *rc, struct btrfs_path *path; struct btrfs_key key; int ret; + bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info, + SKINNY_METADATA); if (tree_block_processed(bytenr, blocksize, rc)) return 0; @@ -3319,10 +3321,15 @@ static int __add_tree_block(struct reloc_control *rc, path = btrfs_alloc_path(); if (!path) return -ENOMEM; - +again: key.objectid = bytenr; - key.type = BTRFS_EXTENT_ITEM_KEY; - key.offset = blocksize; + if (skinny) { + key.type = BTRFS_METADATA_ITEM_KEY; + key.offset = (u64)-1; + } else { + key.type = BTRFS_EXTENT_ITEM_KEY; + key.offset = blocksize; + } path->search_commit_root = 1; path->skip_locking = 1; @@ -3330,11 +3337,23 @@ static int __add_tree_block(struct reloc_control *rc, if (ret < 0) goto out; - btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); - if (ret > 0) { - if (key.objectid == bytenr && - key.type == BTRFS_METADATA_ITEM_KEY) - ret = 0; + if (ret > 0 && skinny) { + if (path->slots[0]) { + path->slots[0]--; + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == bytenr && + (key.type == BTRFS_METADATA_ITEM_KEY || + (key.type == BTRFS_EXTENT_ITEM_KEY && + key.offset == blocksize))) + ret = 0; + } + + if (ret) { + skinny = false; + btrfs_release_path(path); + goto again; + } } BUG_ON(ret); -- 2.20.1