zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/fs/btrfs/delayed-ref.c b/ap/os/linux/linux-3.4.x/fs/btrfs/delayed-ref.c
new file mode 100644
index 0000000..69f22e3
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/btrfs/delayed-ref.c
@@ -0,0 +1,759 @@
+/*
+ * Copyright (C) 2009 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+#include "ctree.h"
+#include "delayed-ref.h"
+#include "transaction.h"
+
+/*
+ * 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 *ref2,
+ struct btrfs_delayed_tree_ref *ref1)
+{
+ 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 *ref2,
+ struct btrfs_delayed_data_ref *ref1)
+{
+ 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;
+}
+
+/*
+ * entries in the rb tree are ordered by the byte number of the extent,
+ * type of the delayed backrefs and content of delayed backrefs.
+ */
+static int comp_entry(struct btrfs_delayed_ref_node *ref2,
+ struct btrfs_delayed_ref_node *ref1)
+{
+ if (ref1->bytenr < ref2->bytenr)
+ return -1;
+ if (ref1->bytenr > ref2->bytenr)
+ return 1;
+ if (ref1->is_head && ref2->is_head)
+ return 0;
+ if (ref2->is_head)
+ return -1;
+ if (ref1->is_head)
+ return 1;
+ if (ref1->type < ref2->type)
+ return -1;
+ if (ref1->type > ref2->type)
+ return 1;
+ /* merging of sequenced refs is not allowed */
+ if (ref1->seq < ref2->seq)
+ return -1;
+ if (ref1->seq > ref2->seq)
+ return 1;
+ if (ref1->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ ref1->type == BTRFS_SHARED_BLOCK_REF_KEY) {
+ return comp_tree_refs(btrfs_delayed_node_to_tree_ref(ref2),
+ btrfs_delayed_node_to_tree_ref(ref1));
+ } else if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY ||
+ ref1->type == BTRFS_SHARED_DATA_REF_KEY) {
+ return comp_data_refs(btrfs_delayed_node_to_data_ref(ref2),
+ btrfs_delayed_node_to_data_ref(ref1));
+ }
+ BUG();
+ return 0;
+}
+
+/*
+ * insert a new ref into the rbtree. This returns any existing refs
+ * for the same (bytenr,parent) tuple, or NULL if the new node was properly
+ * inserted.
+ */
+static struct btrfs_delayed_ref_node *tree_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_node *entry;
+ struct btrfs_delayed_ref_node *ins;
+ int cmp;
+
+ ins = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+ while (*p) {
+ parent_node = *p;
+ entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
+ rb_node);
+
+ cmp = comp_entry(entry, ins);
+ if (cmp < 0)
+ p = &(*p)->rb_left;
+ else if (cmp > 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_node *find_ref_head(struct rb_root *root,
+ u64 bytenr,
+ struct btrfs_delayed_ref_node **last,
+ int return_bigger)
+{
+ struct rb_node *n;
+ struct btrfs_delayed_ref_node *entry;
+ int cmp = 0;
+
+again:
+ n = root->rb_node;
+ entry = NULL;
+ while (n) {
+ entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
+ WARN_ON(!entry->in_tree);
+ if (last)
+ *last = entry;
+
+ if (bytenr < entry->bytenr)
+ cmp = -1;
+ else if (bytenr > entry->bytenr)
+ cmp = 1;
+ else if (!btrfs_delayed_ref_is_head(entry))
+ cmp = 1;
+ else
+ cmp = 0;
+
+ if (cmp < 0)
+ n = n->rb_left;
+ else if (cmp > 0)
+ n = n->rb_right;
+ else
+ return entry;
+ }
+ if (entry && return_bigger) {
+ if (cmp > 0) {
+ n = rb_next(&entry->rb_node);
+ if (!n)
+ n = rb_first(root);
+ entry = rb_entry(n, struct btrfs_delayed_ref_node,
+ rb_node);
+ bytenr = entry->bytenr;
+ return_bigger = 0;
+ goto again;
+ }
+ 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;
+ assert_spin_locked(&delayed_refs->lock);
+ if (mutex_trylock(&head->mutex))
+ return 0;
+
+ atomic_inc(&head->node.refs);
+ spin_unlock(&delayed_refs->lock);
+
+ mutex_lock(&head->mutex);
+ spin_lock(&delayed_refs->lock);
+ if (!head->node.in_tree) {
+ mutex_unlock(&head->mutex);
+ btrfs_put_delayed_ref(&head->node);
+ return -EAGAIN;
+ }
+ btrfs_put_delayed_ref(&head->node);
+ return 0;
+}
+
+int btrfs_check_delayed_seq(struct btrfs_delayed_ref_root *delayed_refs,
+ u64 seq)
+{
+ struct seq_list *elem;
+
+ assert_spin_locked(&delayed_refs->lock);
+ if (list_empty(&delayed_refs->seq_head))
+ return 0;
+
+ elem = list_first_entry(&delayed_refs->seq_head, struct seq_list, list);
+ if (seq >= elem->seq) {
+ pr_debug("holding back delayed_ref %llu, lowest is %llu (%p)\n",
+ seq, elem->seq, delayed_refs);
+ return 1;
+ }
+ return 0;
+}
+
+int btrfs_find_ref_cluster(struct btrfs_trans_handle *trans,
+ struct list_head *cluster, u64 start)
+{
+ int count = 0;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ struct rb_node *node;
+ struct btrfs_delayed_ref_node *ref;
+ struct btrfs_delayed_ref_head *head;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ if (start == 0) {
+ node = rb_first(&delayed_refs->root);
+ } else {
+ ref = NULL;
+ find_ref_head(&delayed_refs->root, start + 1, &ref, 1);
+ if (ref) {
+ node = &ref->rb_node;
+ } else
+ node = rb_first(&delayed_refs->root);
+ }
+again:
+ while (node && count < 32) {
+ ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
+ if (btrfs_delayed_ref_is_head(ref)) {
+ head = btrfs_delayed_node_to_head(ref);
+ if (list_empty(&head->cluster)) {
+ list_add_tail(&head->cluster, cluster);
+ delayed_refs->run_delayed_start =
+ head->node.bytenr;
+ count++;
+
+ WARN_ON(delayed_refs->num_heads_ready == 0);
+ delayed_refs->num_heads_ready--;
+ } else if (count) {
+ /* the goal of the clustering is to find extents
+ * that are likely to end up in the same extent
+ * leaf on disk. So, we don't want them spread
+ * all over the tree. Stop now if we've hit
+ * a head that was already in use
+ */
+ break;
+ }
+ }
+ node = rb_next(node);
+ }
+ if (count) {
+ return 0;
+ } else if (start) {
+ /*
+ * we've gone to the end of the rbtree without finding any
+ * clusters. start from the beginning and try again
+ */
+ start = 0;
+ node = rb_first(&delayed_refs->root);
+ goto again;
+ }
+ return 1;
+}
+
+/*
+ * helper function to update an extent delayed ref in the
+ * rbtree. existing and update must both have the same
+ * bytenr and parent
+ *
+ * This may free existing if the update cancels out whatever
+ * operation it was doing.
+ */
+static noinline void
+update_existing_ref(struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_root *delayed_refs,
+ struct btrfs_delayed_ref_node *existing,
+ struct btrfs_delayed_ref_node *update)
+{
+ if (update->action != existing->action) {
+ /*
+ * this is effectively undoing either an add or a
+ * drop. We decrement the ref_mod, and if it goes
+ * down to zero we just delete the entry without
+ * every changing the extent allocation tree.
+ */
+ existing->ref_mod--;
+ if (existing->ref_mod == 0) {
+ rb_erase(&existing->rb_node,
+ &delayed_refs->root);
+ existing->in_tree = 0;
+ btrfs_put_delayed_ref(existing);
+ delayed_refs->num_entries--;
+ if (trans->delayed_ref_updates)
+ trans->delayed_ref_updates--;
+ } else {
+ WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
+ }
+ } else {
+ WARN_ON(existing->type == BTRFS_TREE_BLOCK_REF_KEY ||
+ existing->type == BTRFS_SHARED_BLOCK_REF_KEY);
+ /*
+ * the action on the existing ref matches
+ * the action on the ref we're trying to add.
+ * Bump the ref_mod by one so the backref that
+ * is eventually added/removed has the correct
+ * reference count
+ */
+ existing->ref_mod += update->ref_mod;
+ }
+}
+
+/*
+ * 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_node *existing,
+ struct btrfs_delayed_ref_node *update)
+{
+ struct btrfs_delayed_ref_head *existing_ref;
+ struct btrfs_delayed_ref_head *ref;
+
+ existing_ref = btrfs_delayed_node_to_head(existing);
+ ref = btrfs_delayed_node_to_head(update);
+ BUG_ON(existing_ref->is_data != ref->is_data);
+
+ if (ref->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_ref->must_insert_reserved = ref->must_insert_reserved;
+
+ /*
+ * update the num_bytes so we make sure the accounting
+ * is done correctly
+ */
+ existing->num_bytes = update->num_bytes;
+
+ }
+
+ if (ref->extent_op) {
+ if (!existing_ref->extent_op) {
+ existing_ref->extent_op = ref->extent_op;
+ } else {
+ if (ref->extent_op->update_key) {
+ memcpy(&existing_ref->extent_op->key,
+ &ref->extent_op->key,
+ sizeof(ref->extent_op->key));
+ existing_ref->extent_op->update_key = 1;
+ }
+ if (ref->extent_op->update_flags) {
+ existing_ref->extent_op->flags_to_set |=
+ ref->extent_op->flags_to_set;
+ existing_ref->extent_op->update_flags = 1;
+ }
+ kfree(ref->extent_op);
+ }
+ }
+ /*
+ * update the reference mod on the head to reflect this new operation
+ */
+ existing->ref_mod += update->ref_mod;
+}
+
+/*
+ * 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 void add_delayed_ref_head(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *ref,
+ u64 bytenr, u64 num_bytes,
+ int action, int is_data)
+{
+ struct btrfs_delayed_ref_node *existing;
+ struct btrfs_delayed_ref_head *head_ref = NULL;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ int count_mod = 1;
+ int must_insert_reserved = 0;
+
+ /*
+ * 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;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ /* first set the basic ref node struct up */
+ atomic_set(&ref->refs, 1);
+ ref->bytenr = bytenr;
+ ref->num_bytes = num_bytes;
+ ref->ref_mod = count_mod;
+ ref->type = 0;
+ ref->action = 0;
+ ref->is_head = 1;
+ ref->in_tree = 1;
+ ref->seq = 0;
+
+ head_ref = btrfs_delayed_node_to_head(ref);
+ head_ref->must_insert_reserved = must_insert_reserved;
+ head_ref->is_data = is_data;
+
+ INIT_LIST_HEAD(&head_ref->cluster);
+ mutex_init(&head_ref->mutex);
+
+ trace_btrfs_delayed_ref_head(ref, head_ref, action);
+
+ existing = tree_insert(&delayed_refs->root, &ref->rb_node);
+
+ if (existing) {
+ update_existing_head_ref(existing, ref);
+ /*
+ * we've updated the existing ref, free the newly
+ * allocated ref
+ */
+ kfree(head_ref);
+ } else {
+ delayed_refs->num_heads++;
+ delayed_refs->num_heads_ready++;
+ delayed_refs->num_entries++;
+ trans->delayed_ref_updates++;
+ }
+}
+
+/*
+ * helper to insert a delayed tree ref into the rbtree.
+ */
+static noinline void add_delayed_tree_ref(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *ref,
+ u64 bytenr, u64 num_bytes, u64 parent,
+ u64 ref_root, int level, int action,
+ int for_cow)
+{
+ struct btrfs_delayed_ref_node *existing;
+ struct btrfs_delayed_tree_ref *full_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ u64 seq = 0;
+
+ if (action == BTRFS_ADD_DELAYED_EXTENT)
+ action = BTRFS_ADD_DELAYED_REF;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ /* first set the basic ref node struct up */
+ atomic_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;
+
+ if (need_ref_seq(for_cow, ref_root))
+ seq = inc_delayed_seq(delayed_refs);
+ ref->seq = seq;
+
+ full_ref = btrfs_delayed_node_to_tree_ref(ref);
+ full_ref->parent = parent;
+ full_ref->root = ref_root;
+ if (parent)
+ ref->type = BTRFS_SHARED_BLOCK_REF_KEY;
+ else
+ ref->type = BTRFS_TREE_BLOCK_REF_KEY;
+ full_ref->level = level;
+
+ trace_btrfs_delayed_tree_ref(ref, full_ref, action);
+
+ existing = tree_insert(&delayed_refs->root, &ref->rb_node);
+
+ if (existing) {
+ update_existing_ref(trans, delayed_refs, existing, ref);
+ /*
+ * we've updated the existing ref, free the newly
+ * allocated ref
+ */
+ kfree(full_ref);
+ } else {
+ delayed_refs->num_entries++;
+ trans->delayed_ref_updates++;
+ }
+}
+
+/*
+ * helper to insert a delayed data ref into the rbtree.
+ */
+static noinline void add_delayed_data_ref(struct btrfs_fs_info *fs_info,
+ struct btrfs_trans_handle *trans,
+ struct btrfs_delayed_ref_node *ref,
+ u64 bytenr, u64 num_bytes, u64 parent,
+ u64 ref_root, u64 owner, u64 offset,
+ int action, int for_cow)
+{
+ struct btrfs_delayed_ref_node *existing;
+ struct btrfs_delayed_data_ref *full_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+ u64 seq = 0;
+
+ if (action == BTRFS_ADD_DELAYED_EXTENT)
+ action = BTRFS_ADD_DELAYED_REF;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+
+ /* first set the basic ref node struct up */
+ atomic_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;
+
+ if (need_ref_seq(for_cow, ref_root))
+ seq = inc_delayed_seq(delayed_refs);
+ ref->seq = seq;
+
+ full_ref = btrfs_delayed_node_to_data_ref(ref);
+ full_ref->parent = parent;
+ full_ref->root = ref_root;
+ if (parent)
+ ref->type = BTRFS_SHARED_DATA_REF_KEY;
+ else
+ ref->type = BTRFS_EXTENT_DATA_REF_KEY;
+
+ full_ref->objectid = owner;
+ full_ref->offset = offset;
+
+ trace_btrfs_delayed_data_ref(ref, full_ref, action);
+
+ existing = tree_insert(&delayed_refs->root, &ref->rb_node);
+
+ if (existing) {
+ update_existing_ref(trans, delayed_refs, existing, ref);
+ /*
+ * we've updated the existing ref, free the newly
+ * allocated ref
+ */
+ kfree(full_ref);
+ } else {
+ delayed_refs->num_entries++;
+ trans->delayed_ref_updates++;
+ }
+}
+
+/*
+ * 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_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 for_cow)
+{
+ struct btrfs_delayed_tree_ref *ref;
+ struct btrfs_delayed_ref_head *head_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+
+ BUG_ON(extent_op && extent_op->is_data);
+ ref = kmalloc(sizeof(*ref), GFP_NOFS);
+ if (!ref)
+ return -ENOMEM;
+
+ head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
+ if (!head_ref) {
+ kfree(ref);
+ return -ENOMEM;
+ }
+
+ 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
+ */
+ add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
+ num_bytes, action, 0);
+
+ add_delayed_tree_ref(fs_info, trans, &ref->node, bytenr,
+ num_bytes, parent, ref_root, level, action,
+ for_cow);
+ if (!need_ref_seq(for_cow, ref_root) &&
+ waitqueue_active(&delayed_refs->seq_wait))
+ wake_up(&delayed_refs->seq_wait);
+ spin_unlock(&delayed_refs->lock);
+ return 0;
+}
+
+/*
+ * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref.
+ */
+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 for_cow)
+{
+ struct btrfs_delayed_data_ref *ref;
+ struct btrfs_delayed_ref_head *head_ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+
+ BUG_ON(extent_op && !extent_op->is_data);
+ ref = kmalloc(sizeof(*ref), GFP_NOFS);
+ if (!ref)
+ return -ENOMEM;
+
+ head_ref = kmalloc(sizeof(*head_ref), GFP_NOFS);
+ if (!head_ref) {
+ kfree(ref);
+ return -ENOMEM;
+ }
+
+ 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
+ */
+ add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
+ num_bytes, action, 1);
+
+ add_delayed_data_ref(fs_info, trans, &ref->node, bytenr,
+ num_bytes, parent, ref_root, owner, offset,
+ action, for_cow);
+ if (!need_ref_seq(for_cow, ref_root) &&
+ waitqueue_active(&delayed_refs->seq_wait))
+ wake_up(&delayed_refs->seq_wait);
+ spin_unlock(&delayed_refs->lock);
+ 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 = kmalloc(sizeof(*head_ref), GFP_NOFS);
+ if (!head_ref)
+ return -ENOMEM;
+
+ head_ref->extent_op = extent_op;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ spin_lock(&delayed_refs->lock);
+
+ add_delayed_ref_head(fs_info, trans, &head_ref->node, bytenr,
+ num_bytes, BTRFS_UPDATE_DELAYED_HEAD,
+ extent_op->is_data);
+
+ if (waitqueue_active(&delayed_refs->seq_wait))
+ wake_up(&delayed_refs->seq_wait);
+ 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_trans_handle *trans, u64 bytenr)
+{
+ struct btrfs_delayed_ref_node *ref;
+ struct btrfs_delayed_ref_root *delayed_refs;
+
+ delayed_refs = &trans->transaction->delayed_refs;
+ ref = find_ref_head(&delayed_refs->root, bytenr, NULL, 0);
+ if (ref)
+ return btrfs_delayed_node_to_head(ref);
+ return NULL;
+}