v4.19.13 snapshot.
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
new file mode 100644
index 0000000..62ff545
--- /dev/null
+++ b/fs/btrfs/delayed-ref.c
@@ -0,0 +1,951 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2009 Oracle. All rights reserved.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include "ctree.h"
+#include "delayed-ref.h"
+#include "transaction.h"
+#include "qgroup.h"
+
+struct kmem_cache *btrfs_delayed_ref_head_cachep;
+struct kmem_cache *btrfs_delayed_tree_ref_cachep;
+struct kmem_cache *btrfs_delayed_data_ref_cachep;
+struct kmem_cache *btrfs_delayed_extent_op_cachep;
+/*
+ * delayed back reference update tracking. For subvolume trees
+ * we queue up extent allocations and backref maintenance for
+ * delayed processing. This avoids deep call chains where we
+ * add extents in the middle of btrfs_search_slot, and it allows
+ * us to buffer up frequently modified backrefs in an rb tree instead
+ * of hammering updates on the extent allocation tree.
+ */
+
+/*
+ * compare two delayed tree backrefs with same bytenr and type
+ */
+static int comp_tree_refs(struct btrfs_delayed_tree_ref *ref1,
+ struct btrfs_delayed_tree_ref *ref2)
+{
+ if (ref1->node.type == BTRFS_TREE_BLOCK_REF_KEY) {
+ if (ref1->root < ref2->root)
+ return -1;
+ if (ref1->root > ref2->root)
+ return 1;
+ } else {
+ if (ref1->parent < ref2->parent)
+ return -1;
+ if (ref1->parent > ref2->parent)
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * compare two delayed data backrefs with same bytenr and type
+ */
+static int comp_data_refs(struct btrfs_delayed_data_ref *ref1,
+ struct btrfs_delayed_data_ref *ref2)
+{
+ if (ref1->node.type == BTRFS_EXTENT_DATA_REF_KEY) {
+ if (ref1->root < ref2->root)
+ return -1;
+ if (ref1->root > ref2->root)
+ return 1;
+ if (ref1->objectid < ref2->objectid)
+ return -1;
+ if (ref1->objectid > ref2->objectid)
+ return 1;
+ if (ref1->offset < ref2->offset)
+ return -1;
+ if (ref1->offset > ref2->offset)
+ return 1;
+ } else {
+ if (ref1->parent < ref2->parent)
+ return -1;
+ if (ref1->parent > ref2->parent)
+ return 1;
+ }
+ return 0;
+}
+
+static int comp_refs(struct btrfs_delayed_ref_node *ref1,
+ struct btrfs_delayed_ref_node *ref2,
+ bool check_seq)
+{
+ int ret = 0;
+
+ if (ref1->type < ref2->type)
+ return -1;
+ if (ref1->type > ref2->type)
+ return 1;
+ if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ ref1->type == BTRFS_SHARED_BLOCK_REF_KEY)
+ ret = comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref1),
+ btrfs_delayed_node_to_tree_ref(ref2));
+ else
+ ret = comp_data_refs(btrfs_delayed_node_to_data_ref(ref1),
+ btrfs_delayed_node_to_data_ref(ref2));
+ if (ret)
+ return ret;
+ if (check_seq) {
+ if (ref1->seq < ref2->seq)
+ return -1;
+ if (ref1->seq > ref2->seq)
+ return 1;
+ }
+ return 0;
+}
+
+/* insert a new ref to head ref rbtree */
+static struct btrfs_delayed_ref_head *htree_insert(struct rb_root *root,
+ struct rb_node *node)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent_node = NULL;
+ struct btrfs_delayed_ref_head *entry;
+ struct btrfs_delayed_ref_head *ins;
+ u64 bytenr;
+
+ ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
+ bytenr = ins->bytenr;
+ while (*p) {
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
+ href_node);
+
+ if (bytenr < entry->bytenr)
+ p = &(*p)->rb_left;
+ else if (bytenr > entry->bytenr)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ rb_link_node(node, parent_node, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
+ struct btrfs_delayed_ref_node *ins)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *node = &ins->ref_node;
+ struct rb_node *parent_node = NULL;
+ struct btrfs_delayed_ref_node *entry;
+
+ while (*p) {
+ int comp;
+
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
+ ref_node);
+ comp = comp_refs(ins, entry, true);
+ if (comp < 0)
+ p = &(*p)->rb_left;
+ else if (comp > 0)
+ p = &(*p)->rb_right;
+ else
+ return entry;
+ }
+
+ rb_link_node(node, parent_node, p);
+ rb_insert_color(node, root);
+ return NULL;
+}
+
+/*
+ * find an head entry based on bytenr. This returns the delayed ref
+ * head if it was able to find one, or NULL if nothing was in that spot.
+ * If return_bigger is given, the next bigger entry is returned if no exact
+ * match is found.
+ */
+static struct btrfs_delayed_ref_head *
+find_ref_head(struct rb_root *root, u64 bytenr,
+ int return_bigger)
+{
+ struct rb_node *n;
+ struct btrfs_delayed_ref_head *entry;
+
+ n = root->rb_node;
+ entry = NULL;
+ while (n) {
+ entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
+
+ if (bytenr < entry->bytenr)
+ n = n->rb_left;
+ else if (bytenr > entry->bytenr)
+ n = n->rb_right;
+ else
+ return entry;
+ }
+ if (entry && return_bigger) {
+ if (bytenr > entry->bytenr) {
+ n = rb_next(&entry->href_node);
+ if (!n)
+ n = rb_first(root);
+ entry = rb_entry(n, struct btrfs_delayed_ref_head,
+ href_node);
+ return entry;
+ }
+ return entry;
+ }
+ return NULL;
+}
+
+int btrfs_delayed_ref_lock(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *head)
+{
+ struct btrfs_delayed_ref_root *delayed_refs;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ lockdep_assert_held(&delayed_refs->lock);
+ if (mutex_trylock(&head->mutex))
+ return 0;
+
+ refcount_inc(&head->refs);
+ spin_unlock(&delayed_refs->lock);
+
+ mutex_lock(&head->mutex);
+ spin_lock(&delayed_refs->lock);
+ if (RB_EMPTY_NODE(&head->href_node)) {
+ mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref_head(head);
+ return -EAGAIN;
+ }
+ btrfs_put_delayed_ref_head(head);
+ return 0;
+}
+
+static inline void drop_delayed_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *head,
+ struct btrfs_delayed_ref_node *ref)
+{
+ lockdep_assert_held(&head->lock);
+ rb_erase(&ref->ref_node, &head->ref_tree);
+ RB_CLEAR_NODE(&ref->ref_node);
+ if (!list_empty(&ref->add_list))
+ list_del(&ref->add_list);
+ ref->in_tree = 0;
+ btrfs_put_delayed_ref(ref);
+ atomic_dec(&delayed_refs->num_entries);
+ if (trans->delayed_ref_updates)
+ trans->delayed_ref_updates--;
+}
+
+static bool merge_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *head,
+ struct btrfs_delayed_ref_node *ref,
+ u64 seq)
+{
+ struct btrfs_delayed_ref_node *next;
+ struct rb_node *node = rb_next(&ref->ref_node);
+ bool done = false;
+
+ while (!done && node) {
+ int mod;
+
+ next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
+ node = rb_next(node);
+ if (seq && next->seq >= seq)
+ break;
+ if (comp_refs(ref, next, false))
+ break;
+
+ if (ref->action == next->action) {
+ mod = next->ref_mod;
+ } else {
+ if (ref->ref_mod < next->ref_mod) {
+ swap(ref, next);
+ done = true;
+ }
+ mod = -next->ref_mod;
+ }
+
+ drop_delayed_ref(trans, delayed_refs, head, next);
+ ref->ref_mod += mod;
+ if (ref->ref_mod == 0) {
+ drop_delayed_ref(trans, delayed_refs, head, ref);
+ done = true;
+ } else {
+ /*
+ * Can't have multiples of the same ref on a tree block.
+ */
+ WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ ref->type == BTRFS_SHARED_BLOCK_REF_KEY);
+ }
+ }
+
+ return done;
+}
+
+void btrfs_merge_delayed_refs(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *head)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_ref_node *ref;
+ struct rb_node *node;
+ u64 seq = 0;
+
+ lockdep_assert_held(&head->lock);
+
+ if (RB_EMPTY_ROOT(&head->ref_tree))
+ return;
+
+ /* We don't have too many refs to merge for data. */
+ if (head->is_data)
+ return;
+
+ spin_lock(&fs_info->tree_mod_seq_lock);
+ if (!list_empty(&fs_info->tree_mod_seq_list)) {
+ struct seq_list *elem;
+
+ elem = list_first_entry(&fs_info->tree_mod_seq_list,
+ struct seq_list, list);
+ seq = elem->seq;
+ }
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+
+again:
+ for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
+ ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
+ if (seq && ref->seq >= seq)
+ continue;
+ if (merge_ref(trans, delayed_refs, head, ref, seq))
+ goto again;
+ }
+}
+
+int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq)
+{
+ struct seq_list *elem;
+ int ret = 0;
+
+ spin_lock(&fs_info->tree_mod_seq_lock);
+ if (!list_empty(&fs_info->tree_mod_seq_list)) {
+ elem = list_first_entry(&fs_info->tree_mod_seq_list,
+ struct seq_list, list);
+ if (seq >= elem->seq) {
+ btrfs_debug(fs_info,
+ "holding back delayed_ref %#x.%x, lowest is %#x.%x",
+ (u32)(seq >> 32), (u32)seq,
+ (u32)(elem->seq >> 32), (u32)elem->seq);
+ ret = 1;
+ }
+ }
+
+ spin_unlock(&fs_info->tree_mod_seq_lock);
+ return ret;
+}
+
+struct btrfs_delayed_ref_head *
+btrfs_select_ref_head(struct btrfs_trans_handle *trans)
+{
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_delayed_ref_head *head;
+ u64 start;
+ bool loop = false;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+again:
+ start = delayed_refs->run_delayed_start;
+ head = find_ref_head(&delayed_refs->href_root, start, 1);
+ if (!head && !loop) {
+ delayed_refs->run_delayed_start = 0;
+ start = 0;
+ loop = true;
+ head = find_ref_head(&delayed_refs->href_root, start, 1);
+ if (!head)
+ return NULL;
+ } else if (!head && loop) {
+ return NULL;
+ }
+
+ while (head->processing) {
+ struct rb_node *node;
+
+ node = rb_next(&head->href_node);
+ if (!node) {
+ if (loop)
+ return NULL;
+ delayed_refs->run_delayed_start = 0;
+ start = 0;
+ loop = true;
+ goto again;
+ }
+ head = rb_entry(node, struct btrfs_delayed_ref_head,
+ href_node);
+ }
+
+ head->processing = 1;
+ WARN_ON(delayed_refs->num_heads_ready == 0);
+ delayed_refs->num_heads_ready--;
+ delayed_refs->run_delayed_start = head->bytenr +
+ head->num_bytes;
+ return head;
+}
+
+/*
+ * Helper to insert the ref_node to the tail or merge with tail.
+ *
+ * Return 0 for insert.
+ * Return >0 for merge.
+ */
+static int insert_delayed_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_root *root,
+ struct btrfs_delayed_ref_head *href,
+ struct btrfs_delayed_ref_node *ref)
+{
+ struct btrfs_delayed_ref_node *exist;
+ int mod;
+ int ret = 0;
+
+ spin_lock(&href->lock);
+ exist = tree_insert(&href->ref_tree, ref);
+ if (!exist)
+ goto inserted;
+
+ /* Now we are sure we can merge */
+ ret = 1;
+ if (exist->action == ref->action) {
+ mod = ref->ref_mod;
+ } else {
+ /* Need to change action */
+ if (exist->ref_mod < ref->ref_mod) {
+ exist->action = ref->action;
+ mod = -exist->ref_mod;
+ exist->ref_mod = ref->ref_mod;
+ if (ref->action == BTRFS_ADD_DELAYED_REF)
+ list_add_tail(&exist->add_list,
+ &href->ref_add_list);
+ else if (ref->action == BTRFS_DROP_DELAYED_REF) {
+ ASSERT(!list_empty(&exist->add_list));
+ list_del(&exist->add_list);
+ } else {
+ ASSERT(0);
+ }
+ } else
+ mod = -ref->ref_mod;
+ }
+ exist->ref_mod += mod;
+
+ /* remove existing tail if its ref_mod is zero */
+ if (exist->ref_mod == 0)
+ drop_delayed_ref(trans, root, href, exist);
+ spin_unlock(&href->lock);
+ return ret;
+inserted:
+ if (ref->action == BTRFS_ADD_DELAYED_REF)
+ list_add_tail(&ref->add_list, &href->ref_add_list);
+ atomic_inc(&root->num_entries);
+ trans->delayed_ref_updates++;
+ spin_unlock(&href->lock);
+ return ret;
+}
+
+/*
+ * helper function to update the accounting in the head ref
+ * existing and update must have the same bytenr
+ */
+static noinline void
+update_existing_head_ref(struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_head *existing,
+ struct btrfs_delayed_ref_head *update,
+ int *old_ref_mod_ret)
+{
+ int old_ref_mod;
+
+ BUG_ON(existing->is_data != update->is_data);
+
+ spin_lock(&existing->lock);
+ if (update->must_insert_reserved) {
+ /* if the extent was freed and then
+ * reallocated before the delayed ref
+ * entries were processed, we can end up
+ * with an existing head ref without
+ * the must_insert_reserved flag set.
+ * Set it again here
+ */
+ existing->must_insert_reserved = update->must_insert_reserved;
+
+ /*
+ * update the num_bytes so we make sure the accounting
+ * is done correctly
+ */
+ existing->num_bytes = update->num_bytes;
+
+ }
+
+ if (update->extent_op) {
+ if (!existing->extent_op) {
+ existing->extent_op = update->extent_op;
+ } else {
+ if (update->extent_op->update_key) {
+ memcpy(&existing->extent_op->key,
+ &update->extent_op->key,
+ sizeof(update->extent_op->key));
+ existing->extent_op->update_key = true;
+ }
+ if (update->extent_op->update_flags) {
+ existing->extent_op->flags_to_set |=
+ update->extent_op->flags_to_set;
+ existing->extent_op->update_flags = true;
+ }
+ btrfs_free_delayed_extent_op(update->extent_op);
+ }
+ }
+ /*
+ * update the reference mod on the head to reflect this new operation,
+ * only need the lock for this case cause we could be processing it
+ * currently, for refs we just added we know we're a-ok.
+ */
+ old_ref_mod = existing->total_ref_mod;
+ if (old_ref_mod_ret)
+ *old_ref_mod_ret = old_ref_mod;
+ existing->ref_mod += update->ref_mod;
+ existing->total_ref_mod += update->ref_mod;
+
+ /*
+ * If we are going to from a positive ref mod to a negative or vice
+ * versa we need to make sure to adjust pending_csums accordingly.
+ */
+ if (existing->is_data) {
+ if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
+ delayed_refs->pending_csums -= existing->num_bytes;
+ if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
+ delayed_refs->pending_csums += existing->num_bytes;
+ }
+ spin_unlock(&existing->lock);
+}
+
+static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref,
+ struct btrfs_qgroup_extent_record *qrecord,
+ u64 bytenr, u64 num_bytes, u64 ref_root,
+ u64 reserved, int action, bool is_data,
+ bool is_system)
+{
+ int count_mod = 1;
+ int must_insert_reserved = 0;
+
+ /* If reserved is provided, it must be a data extent. */
+ BUG_ON(!is_data && reserved);
+
+ /*
+ * The head node stores the sum of all the mods, so dropping a ref
+ * should drop the sum in the head node by one.
+ */
+ if (action == BTRFS_UPDATE_DELAYED_HEAD)
+ count_mod = 0;
+ else if (action == BTRFS_DROP_DELAYED_REF)
+ count_mod = -1;
+
+ /*
+ * BTRFS_ADD_DELAYED_EXTENT means that we need to update the reserved
+ * accounting when the extent is finally added, or if a later
+ * modification deletes the delayed ref without ever inserting the
+ * extent into the extent allocation tree. ref->must_insert_reserved
+ * is the flag used to record that accounting mods are required.
+ *
+ * Once we record must_insert_reserved, switch the action to
+ * BTRFS_ADD_DELAYED_REF because other special casing is not required.
+ */
+ if (action == BTRFS_ADD_DELAYED_EXTENT)
+ must_insert_reserved = 1;
+ else
+ must_insert_reserved = 0;
+
+ refcount_set(&head_ref->refs, 1);
+ head_ref->bytenr = bytenr;
+ head_ref->num_bytes = num_bytes;
+ head_ref->ref_mod = count_mod;
+ head_ref->must_insert_reserved = must_insert_reserved;
+ head_ref->is_data = is_data;
+ head_ref->is_system = is_system;
+ head_ref->ref_tree = RB_ROOT;
+ INIT_LIST_HEAD(&head_ref->ref_add_list);
+ RB_CLEAR_NODE(&head_ref->href_node);
+ head_ref->processing = 0;
+ head_ref->total_ref_mod = count_mod;
+ head_ref->qgroup_reserved = 0;
+ head_ref->qgroup_ref_root = 0;
+ spin_lock_init(&head_ref->lock);
+ mutex_init(&head_ref->mutex);
+
+ if (qrecord) {
+ if (ref_root && reserved) {
+ head_ref->qgroup_ref_root = ref_root;
+ head_ref->qgroup_reserved = reserved;
+ }
+
+ qrecord->bytenr = bytenr;
+ qrecord->num_bytes = num_bytes;
+ qrecord->old_roots = NULL;
+ }
+}
+
+/*
+ * helper function to actually insert a head node into the rbtree.
+ * this does all the dirty work in terms of maintaining the correct
+ * overall modification count.
+ */
+static noinline struct btrfs_delayed_ref_head *
+add_delayed_ref_head(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_head *head_ref,
+ struct btrfs_qgroup_extent_record *qrecord,
+ int action, int *qrecord_inserted_ret,
+ int *old_ref_mod, int *new_ref_mod)
+{
+ struct btrfs_delayed_ref_head *existing;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ int qrecord_inserted = 0;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ /* Record qgroup extent info if provided */
+ if (qrecord) {
+ if (btrfs_qgroup_trace_extent_nolock(trans->fs_info,
+ delayed_refs, qrecord))
+ kfree(qrecord);
+ else
+ qrecord_inserted = 1;
+ }
+
+ trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
+
+ existing = htree_insert(&delayed_refs->href_root,
+ &head_ref->href_node);
+ if (existing) {
+ WARN_ON(qrecord && head_ref->qgroup_ref_root
+ && head_ref->qgroup_reserved
+ && existing->qgroup_ref_root
+ && existing->qgroup_reserved);
+ update_existing_head_ref(delayed_refs, existing, head_ref,
+ old_ref_mod);
+ /*
+ * we've updated the existing ref, free the newly
+ * allocated ref
+ */
+ kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
+ head_ref = existing;
+ } else {
+ if (old_ref_mod)
+ *old_ref_mod = 0;
+ if (head_ref->is_data && head_ref->ref_mod < 0)
+ delayed_refs->pending_csums += head_ref->num_bytes;
+ delayed_refs->num_heads++;
+ delayed_refs->num_heads_ready++;
+ atomic_inc(&delayed_refs->num_entries);
+ trans->delayed_ref_updates++;
+ }
+ if (qrecord_inserted_ret)
+ *qrecord_inserted_ret = qrecord_inserted;
+ if (new_ref_mod)
+ *new_ref_mod = head_ref->total_ref_mod;
+
+ return head_ref;
+}
+
+/*
+ * init_delayed_ref_common - Initialize the structure which represents a
+ * modification to a an extent.
+ *
+ * @fs_info: Internal to the mounted filesystem mount structure.
+ *
+ * @ref: The structure which is going to be initialized.
+ *
+ * @bytenr: The logical address of the extent for which a modification is
+ * going to be recorded.
+ *
+ * @num_bytes: Size of the extent whose modification is being recorded.
+ *
+ * @ref_root: The id of the root where this modification has originated, this
+ * can be either one of the well-known metadata trees or the
+ * subvolume id which references this extent.
+ *
+ * @action: Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or
+ * BTRFS_ADD_DELAYED_EXTENT
+ *
+ * @ref_type: Holds the type of the extent which is being recorded, can be
+ * one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY
+ * when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/
+ * BTRFS_EXTENT_DATA_REF_KEY when recording data extent
+ */
+static void init_delayed_ref_common(struct btrfs_fs_info *fs_info,
+ struct btrfs_delayed_ref_node *ref,
+ u64 bytenr, u64 num_bytes, u64 ref_root,
+ int action, u8 ref_type)
+{
+ u64 seq = 0;
+
+ if (action == BTRFS_ADD_DELAYED_EXTENT)
+ action = BTRFS_ADD_DELAYED_REF;
+
+ if (is_fstree(ref_root))
+ seq = atomic64_read(&fs_info->tree_mod_seq);
+
+ refcount_set(&ref->refs, 1);
+ ref->bytenr = bytenr;
+ ref->num_bytes = num_bytes;
+ ref->ref_mod = 1;
+ ref->action = action;
+ ref->is_head = 0;
+ ref->in_tree = 1;
+ ref->seq = seq;
+ ref->type = ref_type;
+ RB_CLEAR_NODE(&ref->ref_node);
+ INIT_LIST_HEAD(&ref->add_list);
+}
+
+/*
+ * add a delayed tree ref. This does all of the accounting required
+ * to make sure the delayed ref is eventually processed before this
+ * transaction commits.
+ */
+int btrfs_add_delayed_tree_ref(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 *old_ref_mod, int *new_ref_mod)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_tree_ref *ref;
+ struct btrfs_delayed_ref_head *head_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_qgroup_extent_record *record = NULL;
+ int qrecord_inserted;
+ bool is_system = (ref_root == BTRFS_CHUNK_TREE_OBJECTID);
+ int ret;
+ u8 ref_type;
+
+ BUG_ON(extent_op && extent_op->is_data);
+ ref = kmem_cache_alloc(btrfs_delayed_tree_ref_cachep, GFP_NOFS);
+ if (!ref)
+ return -ENOMEM;
+
+ head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
+ if (!head_ref) {
+ kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
+ return -ENOMEM;
+ }
+
+ if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
+ is_fstree(ref_root)) {
+ record = kmalloc(sizeof(*record), GFP_NOFS);
+ if (!record) {
+ kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
+ kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
+ return -ENOMEM;
+ }
+ }
+
+ if (parent)
+ ref_type = BTRFS_SHARED_BLOCK_REF_KEY;
+ else
+ ref_type = BTRFS_TREE_BLOCK_REF_KEY;
+
+ init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
+ ref_root, action, ref_type);
+ ref->root = ref_root;
+ ref->parent = parent;
+ ref->level = level;
+
+ init_delayed_ref_head(head_ref, record, bytenr, num_bytes,
+ ref_root, 0, action, false, is_system);
+ head_ref->extent_op = extent_op;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+
+ /*
+ * insert both the head node and the new ref without dropping
+ * the spin lock
+ */
+ head_ref = add_delayed_ref_head(trans, head_ref, record,
+ action, &qrecord_inserted,
+ old_ref_mod, new_ref_mod);
+
+ ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
+ spin_unlock(&delayed_refs->lock);
+
+ trace_add_delayed_tree_ref(fs_info, &ref->node, ref,
+ action == BTRFS_ADD_DELAYED_EXTENT ?
+ BTRFS_ADD_DELAYED_REF : action);
+ if (ret > 0)
+ kmem_cache_free(btrfs_delayed_tree_ref_cachep, ref);
+
+ if (qrecord_inserted)
+ btrfs_qgroup_trace_extent_post(fs_info, record);
+
+ return 0;
+}
+
+/*
+ * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
+ */
+int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans,
+ u64 bytenr, u64 num_bytes,
+ u64 parent, u64 ref_root,
+ u64 owner, u64 offset, u64 reserved, int action,
+ int *old_ref_mod, int *new_ref_mod)
+{
+ struct btrfs_fs_info *fs_info = trans->fs_info;
+ struct btrfs_delayed_data_ref *ref;
+ struct btrfs_delayed_ref_head *head_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct btrfs_qgroup_extent_record *record = NULL;
+ int qrecord_inserted;
+ int ret;
+ u8 ref_type;
+
+ ref = kmem_cache_alloc(btrfs_delayed_data_ref_cachep, GFP_NOFS);
+ if (!ref)
+ return -ENOMEM;
+
+ if (parent)
+ ref_type = BTRFS_SHARED_DATA_REF_KEY;
+ else
+ ref_type = BTRFS_EXTENT_DATA_REF_KEY;
+ init_delayed_ref_common(fs_info, &ref->node, bytenr, num_bytes,
+ ref_root, action, ref_type);
+ ref->root = ref_root;
+ ref->parent = parent;
+ ref->objectid = owner;
+ ref->offset = offset;
+
+
+ head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
+ if (!head_ref) {
+ kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
+ return -ENOMEM;
+ }
+
+ if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) &&
+ is_fstree(ref_root)) {
+ record = kmalloc(sizeof(*record), GFP_NOFS);
+ if (!record) {
+ kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
+ kmem_cache_free(btrfs_delayed_ref_head_cachep,
+ head_ref);
+ return -ENOMEM;
+ }
+ }
+
+ init_delayed_ref_head(head_ref, record, bytenr, num_bytes, ref_root,
+ reserved, action, true, false);
+ head_ref->extent_op = NULL;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+
+ /*
+ * insert both the head node and the new ref without dropping
+ * the spin lock
+ */
+ head_ref = add_delayed_ref_head(trans, head_ref, record,
+ action, &qrecord_inserted,
+ old_ref_mod, new_ref_mod);
+
+ ret = insert_delayed_ref(trans, delayed_refs, head_ref, &ref->node);
+ spin_unlock(&delayed_refs->lock);
+
+ trace_add_delayed_data_ref(trans->fs_info, &ref->node, ref,
+ action == BTRFS_ADD_DELAYED_EXTENT ?
+ BTRFS_ADD_DELAYED_REF : action);
+ if (ret > 0)
+ kmem_cache_free(btrfs_delayed_data_ref_cachep, ref);
+
+
+ if (qrecord_inserted)
+ return btrfs_qgroup_trace_extent_post(fs_info, record);
+ return 0;
+}
+
+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)
+{
+ struct btrfs_delayed_ref_head *head_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+
+ head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS);
+ if (!head_ref)
+ return -ENOMEM;
+
+ init_delayed_ref_head(head_ref, NULL, bytenr, num_bytes, 0, 0,
+ BTRFS_UPDATE_DELAYED_HEAD, extent_op->is_data,
+ false);
+ head_ref->extent_op = extent_op;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+
+ add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
+ NULL, NULL, NULL);
+
+ spin_unlock(&delayed_refs->lock);
+ return 0;
+}
+
+/*
+ * this does a simple search for the head node for a given extent.
+ * It must be called with the delayed ref spinlock held, and it returns
+ * the head node if any where found, or NULL if not.
+ */
+struct btrfs_delayed_ref_head *
+btrfs_find_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
+{
+ return find_ref_head(&delayed_refs->href_root, bytenr, 0);
+}
+
+void __cold btrfs_delayed_ref_exit(void)
+{
+ kmem_cache_destroy(btrfs_delayed_ref_head_cachep);
+ kmem_cache_destroy(btrfs_delayed_tree_ref_cachep);
+ kmem_cache_destroy(btrfs_delayed_data_ref_cachep);
+ kmem_cache_destroy(btrfs_delayed_extent_op_cachep);
+}
+
+int __init btrfs_delayed_ref_init(void)
+{
+ btrfs_delayed_ref_head_cachep = kmem_cache_create(
+ "btrfs_delayed_ref_head",
+ sizeof(struct btrfs_delayed_ref_head), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!btrfs_delayed_ref_head_cachep)
+ goto fail;
+
+ btrfs_delayed_tree_ref_cachep = kmem_cache_create(
+ "btrfs_delayed_tree_ref",
+ sizeof(struct btrfs_delayed_tree_ref), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!btrfs_delayed_tree_ref_cachep)
+ goto fail;
+
+ btrfs_delayed_data_ref_cachep = kmem_cache_create(
+ "btrfs_delayed_data_ref",
+ sizeof(struct btrfs_delayed_data_ref), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!btrfs_delayed_data_ref_cachep)
+ goto fail;
+
+ btrfs_delayed_extent_op_cachep = kmem_cache_create(
+ "btrfs_delayed_extent_op",
+ sizeof(struct btrfs_delayed_extent_op), 0,
+ SLAB_MEM_SPREAD, NULL);
+ if (!btrfs_delayed_extent_op_cachep)
+ goto fail;
+
+ return 0;
+fail:
+ btrfs_delayed_ref_exit();
+ return -ENOMEM;
+}