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authorJan Schmidt <list.btrfs@jan-o-sch.net>2012-06-05 16:41:24 +0200
committerJan Schmidt <list.btrfs@jan-o-sch.net>2012-06-14 18:44:22 +0200
commita95236d99fa56766f11056903439f55fe5038bcf (patch)
tree90a9ea2656772900ac411cf43333ec25ed712363 /fs/btrfs/ctree.c
parentBtrfs: use btrfs_read_lock_root_node in get_old_root (diff)
downloadlinux-a95236d99fa56766f11056903439f55fe5038bcf.tar.xz
linux-a95236d99fa56766f11056903439f55fe5038bcf.zip
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 <list.btrfs@jan-o-sch.net>
Diffstat (limited to '')
-rw-r--r--fs/btrfs/ctree.c33
1 files changed, 20 insertions, 13 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 2cde7b0a0106..50d7c99ddce7 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);