btrfs: introduce BTRFS_NESTING_COW for cow'ing blocks
When we COW a block we are holding a lock on the original block, and
then we lock the new COW block. Because our lockdep maps are based on
root + level, this will make lockdep complain. We need a way to
indicate a subclass for locking the COW'ed block, so plumb through our
btrfs_lock_nesting from btrfs_cow_block down to the btrfs_init_buffer,
and then introduce BTRFS_NESTING_COW to be used for cow'ing blocks.
The reason I've added all this extra infrastructure is because there
will be need of different nesting classes in follow up patches.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7b61b7b..3b21fee 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4656,7 +4656,8 @@ int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
static struct extent_buffer *
btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
- u64 bytenr, int level, u64 owner)
+ u64 bytenr, int level, u64 owner,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct extent_buffer *buf;
@@ -4679,7 +4680,7 @@ btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
}
btrfs_set_buffer_lockdep_class(owner, buf, level);
- btrfs_tree_lock(buf);
+ __btrfs_tree_lock(buf, nest);
btrfs_clean_tree_block(buf);
clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
@@ -4725,7 +4726,8 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
u64 parent, u64 root_objectid,
const struct btrfs_disk_key *key,
int level, u64 hint,
- u64 empty_size)
+ u64 empty_size,
+ enum btrfs_lock_nesting nest)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_key ins;
@@ -4741,7 +4743,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
if (btrfs_is_testing(fs_info)) {
buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
- level, root_objectid);
+ level, root_objectid, nest);
if (!IS_ERR(buf))
root->alloc_bytenr += blocksize;
return buf;
@@ -4758,7 +4760,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
goto out_unuse;
buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
- root_objectid);
+ root_objectid, nest);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto out_free_reserved;