From a95236d99fa56766f11056903439f55fe5038bcf Mon Sep 17 00:00:00 2001 From: Jan Schmidt Date: Tue, 5 Jun 2012 16:41:24 +0200 Subject: [PATCH] Btrfs: fix return value for __tree_mod_log_oldest_root In __tree_mod_log_oldest_root() we must return the found operation even if it's not a ROOT_REPLACE operation. Otherwise, the caller assumes that there are no operations to be rewinded and returns immediately. The code in the caller is modified to improve readability. Signed-off-by: Jan Schmidt --- fs/btrfs/ctree.c | 33 ++++++++++++++++++++------------- 1 file changed, 20 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 2cde7b0a010..50d7c99ddce 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1023,6 +1023,10 @@ __tree_mod_log_oldest_root(struct btrfs_fs_info *fs_info, looped = 1; } + /* if there's no old root to return, return what we found instead */ + if (!found) + found = tm; + return found; } @@ -1155,18 +1159,24 @@ get_old_root(struct btrfs_root *root, u64 time_seq) { struct tree_mod_elem *tm; struct extent_buffer *eb; - struct tree_mod_root *old_root; + struct tree_mod_root *old_root = NULL; u64 old_generation; + u64 logical; eb = btrfs_read_lock_root_node(root); tm = __tree_mod_log_oldest_root(root->fs_info, root, time_seq); if (!tm) return root->node; - old_root = &tm->old_root; - old_generation = tm->generation; + if (tm->op == MOD_LOG_ROOT_REPLACE) { + old_root = &tm->old_root; + old_generation = tm->generation; + logical = old_root->logical; + } else { + logical = root->node->start; + } - tm = tree_mod_log_search(root->fs_info, old_root->logical, time_seq); + tm = tree_mod_log_search(root->fs_info, logical, time_seq); /* * there was an item in the log when __tree_mod_log_oldest_root * returned. this one must not go away, because the time_seq passed to @@ -1174,26 +1184,23 @@ get_old_root(struct btrfs_root *root, u64 time_seq) */ BUG_ON(!tm); - if (old_root->logical == root->node->start) { - /* there are logged operations for the current root */ - eb = btrfs_clone_extent_buffer(root->node); - } else { - /* there's a root replace operation for the current root */ + if (old_root) eb = alloc_dummy_extent_buffer(tm->index << PAGE_CACHE_SHIFT, root->nodesize); - } + else + eb = btrfs_clone_extent_buffer(root->node); btrfs_tree_read_unlock(root->node); free_extent_buffer(root->node); if (!eb) return NULL; btrfs_tree_read_lock(eb); - if (old_root->logical != root->node->start) { + if (old_root) { btrfs_set_header_bytenr(eb, eb->start); btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV); btrfs_set_header_owner(eb, root->root_key.objectid); + btrfs_set_header_level(eb, old_root->level); + btrfs_set_header_generation(eb, old_generation); } - btrfs_set_header_level(eb, old_root->level); - btrfs_set_header_generation(eb, old_generation); __tree_mod_log_rewind(eb, time_seq, tm); extent_buffer_get(eb); -- 2.41.0