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-rw-r--r--fs/btrfs/delayed-ref.h104
1 files changed, 91 insertions, 13 deletions
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index e287e3b0eab..d8f244d9492 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -33,6 +33,9 @@ struct btrfs_delayed_ref_node {
/* the size of the extent */
u64 num_bytes;
+ /* seq number to keep track of insertion order */
+ u64 seq;
+
/* ref count on this data structure */
atomic_t refs;
@@ -98,19 +101,15 @@ struct btrfs_delayed_ref_head {
struct btrfs_delayed_tree_ref {
struct btrfs_delayed_ref_node node;
- union {
- u64 root;
- u64 parent;
- };
+ u64 root;
+ u64 parent;
int level;
};
struct btrfs_delayed_data_ref {
struct btrfs_delayed_ref_node node;
- union {
- u64 root;
- u64 parent;
- };
+ u64 root;
+ u64 parent;
u64 objectid;
u64 offset;
};
@@ -140,6 +139,26 @@ struct btrfs_delayed_ref_root {
int flushing;
u64 run_delayed_start;
+
+ /*
+ * seq number of delayed refs. We need to know if a backref was being
+ * added before the currently processed ref or afterwards.
+ */
+ u64 seq;
+
+ /*
+ * seq_list holds a list of all seq numbers that are currently being
+ * added to the list. While walking backrefs (btrfs_find_all_roots,
+ * qgroups), which might take some time, no newer ref must be processed,
+ * as it might influence the outcome of the walk.
+ */
+ struct list_head seq_head;
+
+ /*
+ * when the only refs we have in the list must not be processed, we want
+ * to wait for more refs to show up or for the end of backref walking.
+ */
+ wait_queue_head_t seq_wait;
};
static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
@@ -151,16 +170,21 @@ static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
}
}
-int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans,
+int btrfs_add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes, u64 parent,
u64 ref_root, int level, int action,
- struct btrfs_delayed_extent_op *extent_op);
-int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_extent_op *extent_op,
+ int for_cow);
+int btrfs_add_delayed_data_ref(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
u64 parent, u64 ref_root,
u64 owner, u64 offset, int action,
- struct btrfs_delayed_extent_op *extent_op);
-int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_extent_op *extent_op,
+ int for_cow);
+int btrfs_add_delayed_extent_op(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
u64 bytenr, u64 num_bytes,
struct btrfs_delayed_extent_op *extent_op);
@@ -170,6 +194,60 @@ int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
struct btrfs_delayed_ref_head *head);
int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
struct list_head *cluster, u64 search_start);
+
+struct seq_list {
+ struct list_head list;
+ u64 seq;
+};
+
+static inline u64 inc_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs)
+{
+ assert_spin_locked(&delayed_refs->lock);
+ ++delayed_refs->seq;
+ return delayed_refs->seq;
+}
+
+static inline void
+btrfs_get_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+ struct seq_list *elem)
+{
+ assert_spin_locked(&delayed_refs->lock);
+ elem->seq = delayed_refs->seq;
+ list_add_tail(&elem->list, &delayed_refs->seq_head);
+}
+
+static inline void
+btrfs_put_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+ struct seq_list *elem)
+{
+ spin_lock(&delayed_refs->lock);
+ list_del(&elem->list);
+ wake_up(&delayed_refs->seq_wait);
+ spin_unlock(&delayed_refs->lock);
+}
+
+int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+ u64 seq);
+
+/*
+ * delayed refs with a ref_seq > 0 must be held back during backref walking.
+ * this only applies to items in one of the fs-trees. for_cow items never need
+ * to be held back, so they won't get a ref_seq number.
+ */
+static inline int need_ref_seq(int for_cow, u64 rootid)
+{
+ if (for_cow)
+ return 0;
+
+ if (rootid == BTRFS_FS_TREE_OBJECTID)
+ return 1;
+
+ if ((s64)rootid >= (s64)BTRFS_FIRST_FREE_OBJECTID)
+ return 1;
+
+ return 0;
+}
+
/*
* a node might live in a head or a regular ref, this lets you
* test for the proper type to use.