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-rw-r--r--fs/btrfs/ctree.c78
1 files changed, 50 insertions, 28 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f64aad613727..5a6c39b44c84 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -968,6 +968,48 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
return 0;
}
+static struct extent_buffer *alloc_tree_block_no_bg_flush(
+ struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ u64 parent_start,
+ const struct btrfs_disk_key *disk_key,
+ int level,
+ u64 hint,
+ u64 empty_size)
+{
+ struct btrfs_fs_info *fs_info = root->fs_info;
+ struct extent_buffer *ret;
+
+ /*
+ * If we are COWing a node/leaf from the extent, chunk, device or free
+ * space trees, make sure that we do not finish block group creation of
+ * pending block groups. We do this to avoid a deadlock.
+ * COWing can result in allocation of a new chunk, and flushing pending
+ * block groups (btrfs_create_pending_block_groups()) can be triggered
+ * when finishing allocation of a new chunk. Creation of a pending block
+ * group modifies the extent, chunk, device and free space trees,
+ * therefore we could deadlock with ourselves since we are holding a
+ * lock on an extent buffer that btrfs_create_pending_block_groups() may
+ * try to COW later.
+ * For similar reasons, we also need to delay flushing pending block
+ * groups when splitting a leaf or node, from one of those trees, since
+ * we are holding a write lock on it and its parent or when inserting a
+ * new root node for one of those trees.
+ */
+ if (root == fs_info->extent_root ||
+ root == fs_info->chunk_root ||
+ root == fs_info->dev_root ||
+ root == fs_info->free_space_root)
+ trans->can_flush_pending_bgs = false;
+
+ ret = btrfs_alloc_tree_block(trans, root, parent_start,
+ root->root_key.objectid, disk_key, level,
+ hint, empty_size);
+ trans->can_flush_pending_bgs = true;
+
+ return ret;
+}
+
/*
* does the dirty work in cow of a single block. The parent block (if
* supplied) is updated to point to the new cow copy. The new buffer is marked
@@ -1015,28 +1057,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
parent_start = parent->start;
- /*
- * If we are COWing a node/leaf from the extent, chunk, device or free
- * space trees, make sure that we do not finish block group creation of
- * pending block groups. We do this to avoid a deadlock.
- * COWing can result in allocation of a new chunk, and flushing pending
- * block groups (btrfs_create_pending_block_groups()) can be triggered
- * when finishing allocation of a new chunk. Creation of a pending block
- * group modifies the extent, chunk, device and free space trees,
- * therefore we could deadlock with ourselves since we are holding a
- * lock on an extent buffer that btrfs_create_pending_block_groups() may
- * try to COW later.
- */
- if (root == fs_info->extent_root ||
- root == fs_info->chunk_root ||
- root == fs_info->dev_root ||
- root == fs_info->free_space_root)
- trans->can_flush_pending_bgs = false;
-
- cow = btrfs_alloc_tree_block(trans, root, parent_start,
- root->root_key.objectid, &disk_key, level,
- search_start, empty_size);
- trans->can_flush_pending_bgs = true;
+ cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key,
+ level, search_start, empty_size);
if (IS_ERR(cow))
return PTR_ERR(cow);
@@ -3345,8 +3367,8 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
else
btrfs_node_key(lower, &lower_key, 0);
- c = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
- &lower_key, level, root->node->start, 0);
+ c = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level,
+ root->node->start, 0);
if (IS_ERR(c))
return PTR_ERR(c);
@@ -3475,8 +3497,8 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
mid = (c_nritems + 1) / 2;
btrfs_node_key(c, &disk_key, mid);
- split = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
- &disk_key, level, c->start, 0);
+ split = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level,
+ c->start, 0);
if (IS_ERR(split))
return PTR_ERR(split);
@@ -4260,8 +4282,8 @@ again:
else
btrfs_item_key(l, &disk_key, mid);
- right = btrfs_alloc_tree_block(trans, root, 0, root->root_key.objectid,
- &disk_key, 0, l->start, 0);
+ right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,
+ l->start, 0);
if (IS_ERR(right))
return PTR_ERR(right);