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Btrfs: fix locking on ROOT_REPLACE operations in tree mod log

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To resolve backrefs, ROOT_REPLACE operations in the tree mod log are
required to be tied to at least one KEY_REMOVE_WHILE_FREEING operation.
Therefore, those operations must be enclosed by tree_mod_log_write_lock()
and tree_mod_log_write_unlock() calls.

Those calls are private to the tree_mod_log_* functions, which means that
removal of the elements of an old root node must be logged from
tree_mod_log_insert_root. This partly reverts and corrects commit ba1bfbd5
(Btrfs: fix a tree mod logging issue for root replacement operations).

This fixes the brand-new version of xfstest 276 as of commit cfe73f71.

Cc: stable@vger.kernel.org
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
This commit is contained in:
Jan Schmidt 2013-03-20 13:49:48 +00:00 committed by Chris Mason
parent 6113077cd3
commit d9abbf1c31
1 changed files with 20 additions and 10 deletions
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30
fs/btrfs/ctree.c
View file

@ -651,6 +651,8 @@ tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
if (tree_mod_dont_log(fs_info, NULL))
return 0;
__tree_mod_log_free_eb(fs_info, old_root);
ret = tree_mod_alloc(fs_info, flags, &tm);
if (ret < 0)
goto out;
@ -736,7 +738,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
static noinline void
tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
struct extent_buffer *src, unsigned long dst_offset,
unsigned long src_offset, int nr_items)
unsigned long src_offset, int nr_items, int log_removal)
{
int ret;
int i;
@ -750,10 +752,12 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
}
for (i = 0; i < nr_items; i++) {
ret = tree_mod_log_insert_key_locked(fs_info, src,
i + src_offset,
MOD_LOG_KEY_REMOVE);
BUG_ON(ret < 0);
if (log_removal) {
ret = tree_mod_log_insert_key_locked(fs_info, src,
i + src_offset,
MOD_LOG_KEY_REMOVE);
BUG_ON(ret < 0);
}
ret = tree_mod_log_insert_key_locked(fs_info, dst,
i + dst_offset,
MOD_LOG_KEY_ADD);
@ -927,7 +931,6 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
ret = btrfs_dec_ref(trans, root, buf, 1, 1);
BUG_ON(ret); /* -ENOMEM */
}
tree_mod_log_free_eb(root->fs_info, buf);
clean_tree_block(trans, root, buf);
*last_ref = 1;
}
@ -1046,6 +1049,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
btrfs_set_node_ptr_generation(parent, parent_slot,
trans->transid);
btrfs_mark_buffer_dirty(parent);
tree_mod_log_free_eb(root->fs_info, buf);
btrfs_free_tree_block(trans, root, buf, parent_start,
last_ref);
}
@ -1750,7 +1754,6 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
goto enospc;
}
tree_mod_log_free_eb(root->fs_info, root->node);
tree_mod_log_set_root_pointer(root, child);
rcu_assign_pointer(root->node, child);
@ -2995,7 +2998,7 @@ static int push_node_left(struct btrfs_trans_handle *trans,
push_items = min(src_nritems - 8, push_items);
tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
push_items);
push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(dst_nritems),
btrfs_node_key_ptr_offset(0),
@ -3066,7 +3069,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
sizeof(struct btrfs_key_ptr));
tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
src_nritems - push_items, push_items);
src_nritems - push_items, push_items, 1);
copy_extent_buffer(dst, src,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(src_nritems - push_items),
@ -3218,12 +3221,18 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
int mid;
int ret;
u32 c_nritems;
int tree_mod_log_removal = 1;
c = path->nodes[level];
WARN_ON(btrfs_header_generation(c) != trans->transid);
if (c == root->node) {
/* trying to split the root, lets make a new one */
ret = insert_new_root(trans, root, path, level + 1);
/*
* removal of root nodes has been logged by
* tree_mod_log_set_root_pointer due to locking
*/
tree_mod_log_removal = 0;
if (ret)
return ret;
} else {
@ -3261,7 +3270,8 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
(unsigned long)btrfs_header_chunk_tree_uuid(split),
BTRFS_UUID_SIZE);
tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid,
tree_mod_log_removal);
copy_extent_buffer(split, c,
btrfs_node_key_ptr_offset(0),
btrfs_node_key_ptr_offset(mid),