[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/btrfs/ctree.c b/ap/os/linux/linux-3.4.x/fs/btrfs/ctree.c
new file mode 100644
index 0000000..ae47cc2
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/btrfs/ctree.c
@@ -0,0 +1,4382 @@
+/*
+ * Copyright (C) 2007,2008 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 "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "print-tree.h"
+#include "locking.h"
+
+static int split_node(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_path *path, int level);
+static int split_leaf(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *ins_key,
+ struct btrfs_path *path, int data_size, int extend);
+static int push_node_left(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *dst,
+ struct extent_buffer *src, int empty);
+static int balance_node_right(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *dst_buf,
+ struct extent_buffer *src_buf);
+static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_path *path, int level, int slot);
+
+struct btrfs_path *btrfs_alloc_path(void)
+{
+ struct btrfs_path *path;
+ path = kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
+ return path;
+}
+
+/*
+ * set all locked nodes in the path to blocking locks. This should
+ * be done before scheduling
+ */
+noinline void btrfs_set_path_blocking(struct btrfs_path *p)
+{
+ int i;
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+ if (!p->nodes[i] || !p->locks[i])
+ continue;
+ btrfs_set_lock_blocking_rw(p->nodes[i], p->locks[i]);
+ if (p->locks[i] == BTRFS_READ_LOCK)
+ p->locks[i] = BTRFS_READ_LOCK_BLOCKING;
+ else if (p->locks[i] == BTRFS_WRITE_LOCK)
+ p->locks[i] = BTRFS_WRITE_LOCK_BLOCKING;
+ }
+}
+
+/*
+ * reset all the locked nodes in the patch to spinning locks.
+ *
+ * held is used to keep lockdep happy, when lockdep is enabled
+ * we set held to a blocking lock before we go around and
+ * retake all the spinlocks in the path. You can safely use NULL
+ * for held
+ */
+noinline void btrfs_clear_path_blocking(struct btrfs_path *p,
+ struct extent_buffer *held, int held_rw)
+{
+ int i;
+
+#if (defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_PREEMPT_RT_BASE))
+ /* lockdep really cares that we take all of these spinlocks
+ * in the right order. If any of the locks in the path are not
+ * currently blocking, it is going to complain. So, make really
+ * really sure by forcing the path to blocking before we clear
+ * the path blocking.
+ */
+ if (held) {
+ btrfs_set_lock_blocking_rw(held, held_rw);
+ if (held_rw == BTRFS_WRITE_LOCK)
+ held_rw = BTRFS_WRITE_LOCK_BLOCKING;
+ else if (held_rw == BTRFS_READ_LOCK)
+ held_rw = BTRFS_READ_LOCK_BLOCKING;
+ }
+ btrfs_set_path_blocking(p);
+#endif
+
+ for (i = BTRFS_MAX_LEVEL - 1; i >= 0; i--) {
+ if (p->nodes[i] && p->locks[i]) {
+ btrfs_clear_lock_blocking_rw(p->nodes[i], p->locks[i]);
+ if (p->locks[i] == BTRFS_WRITE_LOCK_BLOCKING)
+ p->locks[i] = BTRFS_WRITE_LOCK;
+ else if (p->locks[i] == BTRFS_READ_LOCK_BLOCKING)
+ p->locks[i] = BTRFS_READ_LOCK;
+ }
+ }
+
+#if (defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_PREEMPT_RT_BASE))
+ if (held)
+ btrfs_clear_lock_blocking_rw(held, held_rw);
+#endif
+}
+
+/* this also releases the path */
+void btrfs_free_path(struct btrfs_path *p)
+{
+ if (!p)
+ return;
+ btrfs_release_path(p);
+ kmem_cache_free(btrfs_path_cachep, p);
+}
+
+/*
+ * path release drops references on the extent buffers in the path
+ * and it drops any locks held by this path
+ *
+ * It is safe to call this on paths that no locks or extent buffers held.
+ */
+noinline void btrfs_release_path(struct btrfs_path *p)
+{
+ int i;
+
+ for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
+ p->slots[i] = 0;
+ if (!p->nodes[i])
+ continue;
+ if (p->locks[i]) {
+ btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
+ p->locks[i] = 0;
+ }
+ free_extent_buffer(p->nodes[i]);
+ p->nodes[i] = NULL;
+ }
+}
+
+/*
+ * safely gets a reference on the root node of a tree. A lock
+ * is not taken, so a concurrent writer may put a different node
+ * at the root of the tree. See btrfs_lock_root_node for the
+ * looping required.
+ *
+ * The extent buffer returned by this has a reference taken, so
+ * it won't disappear. It may stop being the root of the tree
+ * at any time because there are no locks held.
+ */
+struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
+{
+ struct extent_buffer *eb;
+
+ while (1) {
+ rcu_read_lock();
+ eb = rcu_dereference(root->node);
+
+ /*
+ * RCU really hurts here, we could free up the root node because
+ * it was cow'ed but we may not get the new root node yet so do
+ * the inc_not_zero dance and if it doesn't work then
+ * synchronize_rcu and try again.
+ */
+ if (atomic_inc_not_zero(&eb->refs)) {
+ rcu_read_unlock();
+ break;
+ }
+ rcu_read_unlock();
+ synchronize_rcu();
+ }
+ return eb;
+}
+
+/* loop around taking references on and locking the root node of the
+ * tree until you end up with a lock on the root. A locked buffer
+ * is returned, with a reference held.
+ */
+struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root)
+{
+ struct extent_buffer *eb;
+
+ while (1) {
+ eb = btrfs_root_node(root);
+ btrfs_tree_lock(eb);
+ if (eb == root->node)
+ break;
+ btrfs_tree_unlock(eb);
+ free_extent_buffer(eb);
+ }
+ return eb;
+}
+
+/* loop around taking references on and locking the root node of the
+ * tree until you end up with a lock on the root. A locked buffer
+ * is returned, with a reference held.
+ */
+struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root)
+{
+ struct extent_buffer *eb;
+
+ while (1) {
+ eb = btrfs_root_node(root);
+ btrfs_tree_read_lock(eb);
+ if (eb == root->node)
+ break;
+ btrfs_tree_read_unlock(eb);
+ free_extent_buffer(eb);
+ }
+ return eb;
+}
+
+/* cowonly root (everything not a reference counted cow subvolume), just get
+ * put onto a simple dirty list. transaction.c walks this to make sure they
+ * get properly updated on disk.
+ */
+static void add_root_to_dirty_list(struct btrfs_root *root)
+{
+ spin_lock(&root->fs_info->trans_lock);
+ if (root->track_dirty && list_empty(&root->dirty_list)) {
+ list_add(&root->dirty_list,
+ &root->fs_info->dirty_cowonly_roots);
+ }
+ spin_unlock(&root->fs_info->trans_lock);
+}
+
+/*
+ * used by snapshot creation to make a copy of a root for a tree with
+ * a given objectid. The buffer with the new root node is returned in
+ * cow_ret, and this func returns zero on success or a negative error code.
+ */
+int btrfs_copy_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ struct extent_buffer **cow_ret, u64 new_root_objectid)
+{
+ struct extent_buffer *cow;
+ int ret = 0;
+ int level;
+ struct btrfs_disk_key disk_key;
+
+ WARN_ON(root->ref_cows && trans->transid !=
+ root->fs_info->running_transaction->transid);
+ WARN_ON(root->ref_cows && trans->transid != root->last_trans);
+
+ level = btrfs_header_level(buf);
+ if (level == 0)
+ btrfs_item_key(buf, &disk_key, 0);
+ else
+ btrfs_node_key(buf, &disk_key, 0);
+
+ cow = btrfs_alloc_free_block(trans, root, buf->len, 0,
+ new_root_objectid, &disk_key, level,
+ buf->start, 0, 1);
+ if (IS_ERR(cow))
+ return PTR_ERR(cow);
+
+ copy_extent_buffer(cow, buf, 0, 0, cow->len);
+ btrfs_set_header_bytenr(cow, cow->start);
+ btrfs_set_header_generation(cow, trans->transid);
+ btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
+ btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
+ BTRFS_HEADER_FLAG_RELOC);
+ if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
+ btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
+ else
+ btrfs_set_header_owner(cow, new_root_objectid);
+
+ write_extent_buffer(cow, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(cow),
+ BTRFS_FSID_SIZE);
+
+ WARN_ON(btrfs_header_generation(buf) > trans->transid);
+ if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
+ ret = btrfs_inc_ref(trans, root, cow, 1, 1);
+ else
+ ret = btrfs_inc_ref(trans, root, cow, 0, 1);
+
+ if (ret)
+ return ret;
+
+ btrfs_mark_buffer_dirty(cow);
+ *cow_ret = cow;
+ return 0;
+}
+
+/*
+ * check if the tree block can be shared by multiple trees
+ */
+int btrfs_block_can_be_shared(struct btrfs_root *root,
+ struct extent_buffer *buf)
+{
+ /*
+ * Tree blocks not in refernece counted trees and tree roots
+ * are never shared. If a block was allocated after the last
+ * snapshot and the block was not allocated by tree relocation,
+ * we know the block is not shared.
+ */
+ if (root->ref_cows &&
+ buf != root->node && buf != root->commit_root &&
+ (btrfs_header_generation(buf) <=
+ btrfs_root_last_snapshot(&root->root_item) ||
+ btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)))
+ return 1;
+#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
+ if (root->ref_cows &&
+ btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
+ return 1;
+#endif
+ return 0;
+}
+
+static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ struct extent_buffer *cow,
+ int *last_ref)
+{
+ u64 refs;
+ u64 owner;
+ u64 flags;
+ u64 new_flags = 0;
+ int ret;
+
+ /*
+ * Backrefs update rules:
+ *
+ * Always use full backrefs for extent pointers in tree block
+ * allocated by tree relocation.
+ *
+ * If a shared tree block is no longer referenced by its owner
+ * tree (btrfs_header_owner(buf) == root->root_key.objectid),
+ * use full backrefs for extent pointers in tree block.
+ *
+ * If a tree block is been relocating
+ * (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID),
+ * use full backrefs for extent pointers in tree block.
+ * The reason for this is some operations (such as drop tree)
+ * are only allowed for blocks use full backrefs.
+ */
+
+ if (btrfs_block_can_be_shared(root, buf)) {
+ ret = btrfs_lookup_extent_info(trans, root, buf->start,
+ buf->len, &refs, &flags);
+ if (ret)
+ return ret;
+ if (refs == 0) {
+ ret = -EROFS;
+ btrfs_std_error(root->fs_info, ret);
+ return ret;
+ }
+ } else {
+ refs = 1;
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
+ btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
+ flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
+ else
+ flags = 0;
+ }
+
+ owner = btrfs_header_owner(buf);
+ BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
+ !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
+
+ if (refs > 1) {
+ if ((owner == root->root_key.objectid ||
+ root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
+ !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
+ ret = btrfs_inc_ref(trans, root, buf, 1, 1);
+ BUG_ON(ret); /* -ENOMEM */
+
+ if (root->root_key.objectid ==
+ BTRFS_TREE_RELOC_OBJECTID) {
+ ret = btrfs_dec_ref(trans, root, buf, 0, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ ret = btrfs_inc_ref(trans, root, cow, 1, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ }
+ new_flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
+ } else {
+
+ if (root->root_key.objectid ==
+ BTRFS_TREE_RELOC_OBJECTID)
+ ret = btrfs_inc_ref(trans, root, cow, 1, 1);
+ else
+ ret = btrfs_inc_ref(trans, root, cow, 0, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ }
+ if (new_flags != 0) {
+ ret = btrfs_set_disk_extent_flags(trans, root,
+ buf->start,
+ buf->len,
+ new_flags, 0);
+ if (ret)
+ return ret;
+ }
+ } else {
+ if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
+ if (root->root_key.objectid ==
+ BTRFS_TREE_RELOC_OBJECTID)
+ ret = btrfs_inc_ref(trans, root, cow, 1, 1);
+ else
+ ret = btrfs_inc_ref(trans, root, cow, 0, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ ret = btrfs_dec_ref(trans, root, buf, 1, 1);
+ BUG_ON(ret); /* -ENOMEM */
+ }
+ clean_tree_block(trans, root, buf);
+ *last_ref = 1;
+ }
+ return 0;
+}
+
+/*
+ * 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
+ * dirty and returned locked. If you modify the block it needs to be marked
+ * dirty again.
+ *
+ * search_start -- an allocation hint for the new block
+ *
+ * empty_size -- a hint that you plan on doing more cow. This is the size in
+ * bytes the allocator should try to find free next to the block it returns.
+ * This is just a hint and may be ignored by the allocator.
+ */
+static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf,
+ struct extent_buffer *parent, int parent_slot,
+ struct extent_buffer **cow_ret,
+ u64 search_start, u64 empty_size)
+{
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *cow;
+ int level, ret;
+ int last_ref = 0;
+ int unlock_orig = 0;
+ u64 parent_start;
+
+ if (*cow_ret == buf)
+ unlock_orig = 1;
+
+ btrfs_assert_tree_locked(buf);
+
+ WARN_ON(root->ref_cows && trans->transid !=
+ root->fs_info->running_transaction->transid);
+ WARN_ON(root->ref_cows && trans->transid != root->last_trans);
+
+ level = btrfs_header_level(buf);
+
+ if (level == 0)
+ btrfs_item_key(buf, &disk_key, 0);
+ else
+ btrfs_node_key(buf, &disk_key, 0);
+
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
+ if (parent)
+ parent_start = parent->start;
+ else
+ parent_start = 0;
+ } else
+ parent_start = 0;
+
+ cow = btrfs_alloc_free_block(trans, root, buf->len, parent_start,
+ root->root_key.objectid, &disk_key,
+ level, search_start, empty_size, 1);
+ if (IS_ERR(cow))
+ return PTR_ERR(cow);
+
+ /* cow is set to blocking by btrfs_init_new_buffer */
+
+ copy_extent_buffer(cow, buf, 0, 0, cow->len);
+ btrfs_set_header_bytenr(cow, cow->start);
+ btrfs_set_header_generation(cow, trans->transid);
+ btrfs_set_header_backref_rev(cow, BTRFS_MIXED_BACKREF_REV);
+ btrfs_clear_header_flag(cow, BTRFS_HEADER_FLAG_WRITTEN |
+ BTRFS_HEADER_FLAG_RELOC);
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ btrfs_set_header_flag(cow, BTRFS_HEADER_FLAG_RELOC);
+ else
+ btrfs_set_header_owner(cow, root->root_key.objectid);
+
+ write_extent_buffer(cow, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(cow),
+ BTRFS_FSID_SIZE);
+
+ ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
+ if (ret) {
+ btrfs_abort_transaction(trans, root, ret);
+ return ret;
+ }
+
+ if (root->ref_cows)
+ btrfs_reloc_cow_block(trans, root, buf, cow);
+
+ if (buf == root->node) {
+ WARN_ON(parent && parent != buf);
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
+ btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
+ parent_start = buf->start;
+ else
+ parent_start = 0;
+
+ extent_buffer_get(cow);
+ rcu_assign_pointer(root->node, cow);
+
+ btrfs_free_tree_block(trans, root, buf, parent_start,
+ last_ref, 1);
+ free_extent_buffer(buf);
+ add_root_to_dirty_list(root);
+ } else {
+ if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
+ parent_start = parent->start;
+ else
+ parent_start = 0;
+
+ WARN_ON(trans->transid != btrfs_header_generation(parent));
+ btrfs_set_node_blockptr(parent, parent_slot,
+ cow->start);
+ btrfs_set_node_ptr_generation(parent, parent_slot,
+ trans->transid);
+ btrfs_mark_buffer_dirty(parent);
+ btrfs_free_tree_block(trans, root, buf, parent_start,
+ last_ref, 1);
+ }
+ if (unlock_orig)
+ btrfs_tree_unlock(buf);
+ free_extent_buffer_stale(buf);
+ btrfs_mark_buffer_dirty(cow);
+ *cow_ret = cow;
+ return 0;
+}
+
+static inline int should_cow_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *buf)
+{
+ /* ensure we can see the force_cow */
+ smp_rmb();
+
+ /*
+ * We do not need to cow a block if
+ * 1) this block is not created or changed in this transaction;
+ * 2) this block does not belong to TREE_RELOC tree;
+ * 3) the root is not forced COW.
+ *
+ * What is forced COW:
+ * when we create snapshot during commiting the transaction,
+ * after we've finished coping src root, we must COW the shared
+ * block to ensure the metadata consistency.
+ */
+ if (btrfs_header_generation(buf) == trans->transid &&
+ !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
+ !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
+ btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
+ !root->force_cow)
+ return 0;
+ return 1;
+}
+
+/*
+ * cows a single block, see __btrfs_cow_block for the real work.
+ * This version of it has extra checks so that a block isn't cow'd more than
+ * once per transaction, as long as it hasn't been written yet
+ */
+noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *buf,
+ struct extent_buffer *parent, int parent_slot,
+ struct extent_buffer **cow_ret)
+{
+ u64 search_start;
+ int ret;
+
+ if (trans->transaction != root->fs_info->running_transaction) {
+ printk(KERN_CRIT "trans %llu running %llu\n",
+ (unsigned long long)trans->transid,
+ (unsigned long long)
+ root->fs_info->running_transaction->transid);
+ WARN_ON(1);
+ }
+ if (trans->transid != root->fs_info->generation) {
+ printk(KERN_CRIT "trans %llu running %llu\n",
+ (unsigned long long)trans->transid,
+ (unsigned long long)root->fs_info->generation);
+ WARN_ON(1);
+ }
+
+ if (!should_cow_block(trans, root, buf)) {
+ *cow_ret = buf;
+ return 0;
+ }
+
+ search_start = buf->start & ~((u64)(1024 * 1024 * 1024) - 1);
+
+ if (parent)
+ btrfs_set_lock_blocking(parent);
+ btrfs_set_lock_blocking(buf);
+
+ ret = __btrfs_cow_block(trans, root, buf, parent,
+ parent_slot, cow_ret, search_start, 0);
+
+ trace_btrfs_cow_block(root, buf, *cow_ret);
+
+ return ret;
+}
+
+/*
+ * helper function for defrag to decide if two blocks pointed to by a
+ * node are actually close by
+ */
+static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
+{
+ if (blocknr < other && other - (blocknr + blocksize) < 32768)
+ return 1;
+ if (blocknr > other && blocknr - (other + blocksize) < 32768)
+ return 1;
+ return 0;
+}
+
+/*
+ * compare two keys in a memcmp fashion
+ */
+static int comp_keys(struct btrfs_disk_key *disk, struct btrfs_key *k2)
+{
+ struct btrfs_key k1;
+
+ btrfs_disk_key_to_cpu(&k1, disk);
+
+ return btrfs_comp_cpu_keys(&k1, k2);
+}
+
+/*
+ * same as comp_keys only with two btrfs_key's
+ */
+int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2)
+{
+ if (k1->objectid > k2->objectid)
+ return 1;
+ if (k1->objectid < k2->objectid)
+ return -1;
+ if (k1->type > k2->type)
+ return 1;
+ if (k1->type < k2->type)
+ return -1;
+ if (k1->offset > k2->offset)
+ return 1;
+ if (k1->offset < k2->offset)
+ return -1;
+ return 0;
+}
+
+/*
+ * this is used by the defrag code to go through all the
+ * leaves pointed to by a node and reallocate them so that
+ * disk order is close to key order
+ */
+int btrfs_realloc_node(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *parent,
+ int start_slot, int cache_only, u64 *last_ret,
+ struct btrfs_key *progress)
+{
+ struct extent_buffer *cur;
+ u64 blocknr;
+ u64 gen;
+ u64 search_start = *last_ret;
+ u64 last_block = 0;
+ u64 other;
+ u32 parent_nritems;
+ int end_slot;
+ int i;
+ int err = 0;
+ int parent_level;
+ int uptodate;
+ u32 blocksize;
+ int progress_passed = 0;
+ struct btrfs_disk_key disk_key;
+
+ parent_level = btrfs_header_level(parent);
+ if (cache_only && parent_level != 1)
+ return 0;
+
+ if (trans->transaction != root->fs_info->running_transaction)
+ WARN_ON(1);
+ if (trans->transid != root->fs_info->generation)
+ WARN_ON(1);
+
+ parent_nritems = btrfs_header_nritems(parent);
+ blocksize = btrfs_level_size(root, parent_level - 1);
+ end_slot = parent_nritems;
+
+ if (parent_nritems == 1)
+ return 0;
+
+ btrfs_set_lock_blocking(parent);
+
+ for (i = start_slot; i < end_slot; i++) {
+ int close = 1;
+
+ btrfs_node_key(parent, &disk_key, i);
+ if (!progress_passed && comp_keys(&disk_key, progress) < 0)
+ continue;
+
+ progress_passed = 1;
+ blocknr = btrfs_node_blockptr(parent, i);
+ gen = btrfs_node_ptr_generation(parent, i);
+ if (last_block == 0)
+ last_block = blocknr;
+
+ if (i > 0) {
+ other = btrfs_node_blockptr(parent, i - 1);
+ close = close_blocks(blocknr, other, blocksize);
+ }
+ if (!close && i < end_slot - 2) {
+ other = btrfs_node_blockptr(parent, i + 1);
+ close = close_blocks(blocknr, other, blocksize);
+ }
+ if (close) {
+ last_block = blocknr;
+ continue;
+ }
+
+ cur = btrfs_find_tree_block(root, blocknr, blocksize);
+ if (cur)
+ uptodate = btrfs_buffer_uptodate(cur, gen, 0);
+ else
+ uptodate = 0;
+ if (!cur || !uptodate) {
+ if (cache_only) {
+ free_extent_buffer(cur);
+ continue;
+ }
+ if (!cur) {
+ cur = read_tree_block(root, blocknr,
+ blocksize, gen);
+ if (!cur)
+ return -EIO;
+ } else if (!uptodate) {
+ btrfs_read_buffer(cur, gen);
+ }
+ }
+ if (search_start == 0)
+ search_start = last_block;
+
+ btrfs_tree_lock(cur);
+ btrfs_set_lock_blocking(cur);
+ err = __btrfs_cow_block(trans, root, cur, parent, i,
+ &cur, search_start,
+ min(16 * blocksize,
+ (end_slot - i) * blocksize));
+ if (err) {
+ btrfs_tree_unlock(cur);
+ free_extent_buffer(cur);
+ break;
+ }
+ search_start = cur->start;
+ last_block = cur->start;
+ *last_ret = search_start;
+ btrfs_tree_unlock(cur);
+ free_extent_buffer(cur);
+ }
+ return err;
+}
+
+/*
+ * The leaf data grows from end-to-front in the node.
+ * this returns the address of the start of the last item,
+ * which is the stop of the leaf data stack
+ */
+static inline unsigned int leaf_data_end(struct btrfs_root *root,
+ struct extent_buffer *leaf)
+{
+ u32 nr = btrfs_header_nritems(leaf);
+ if (nr == 0)
+ return BTRFS_LEAF_DATA_SIZE(root);
+ return btrfs_item_offset_nr(leaf, nr - 1);
+}
+
+
+/*
+ * search for key in the extent_buffer. The items start at offset p,
+ * and they are item_size apart. There are 'max' items in p.
+ *
+ * the slot in the array is returned via slot, and it points to
+ * the place where you would insert key if it is not found in
+ * the array.
+ *
+ * slot may point to max if the key is bigger than all of the keys
+ */
+static noinline int generic_bin_search(struct extent_buffer *eb,
+ unsigned long p,
+ int item_size, struct btrfs_key *key,
+ int max, int *slot)
+{
+ int low = 0;
+ int high = max;
+ int mid;
+ int ret;
+ struct btrfs_disk_key *tmp = NULL;
+ struct btrfs_disk_key unaligned;
+ unsigned long offset;
+ char *kaddr = NULL;
+ unsigned long map_start = 0;
+ unsigned long map_len = 0;
+ int err;
+
+ while (low < high) {
+ mid = (low + high) / 2;
+ offset = p + mid * item_size;
+
+ if (!kaddr || offset < map_start ||
+ (offset + sizeof(struct btrfs_disk_key)) >
+ map_start + map_len) {
+
+ err = map_private_extent_buffer(eb, offset,
+ sizeof(struct btrfs_disk_key),
+ &kaddr, &map_start, &map_len);
+
+ if (!err) {
+ tmp = (struct btrfs_disk_key *)(kaddr + offset -
+ map_start);
+ } else {
+ read_extent_buffer(eb, &unaligned,
+ offset, sizeof(unaligned));
+ tmp = &unaligned;
+ }
+
+ } else {
+ tmp = (struct btrfs_disk_key *)(kaddr + offset -
+ map_start);
+ }
+ ret = comp_keys(tmp, key);
+
+ if (ret < 0)
+ low = mid + 1;
+ else if (ret > 0)
+ high = mid;
+ else {
+ *slot = mid;
+ return 0;
+ }
+ }
+ *slot = low;
+ return 1;
+}
+
+/*
+ * simple bin_search frontend that does the right thing for
+ * leaves vs nodes
+ */
+static int bin_search(struct extent_buffer *eb, struct btrfs_key *key,
+ int level, int *slot)
+{
+ if (level == 0) {
+ return generic_bin_search(eb,
+ offsetof(struct btrfs_leaf, items),
+ sizeof(struct btrfs_item),
+ key, btrfs_header_nritems(eb),
+ slot);
+ } else {
+ return generic_bin_search(eb,
+ offsetof(struct btrfs_node, ptrs),
+ sizeof(struct btrfs_key_ptr),
+ key, btrfs_header_nritems(eb),
+ slot);
+ }
+ return -1;
+}
+
+int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
+ int level, int *slot)
+{
+ return bin_search(eb, key, level, slot);
+}
+
+static void root_add_used(struct btrfs_root *root, u32 size)
+{
+ spin_lock(&root->accounting_lock);
+ btrfs_set_root_used(&root->root_item,
+ btrfs_root_used(&root->root_item) + size);
+ spin_unlock(&root->accounting_lock);
+}
+
+static void root_sub_used(struct btrfs_root *root, u32 size)
+{
+ spin_lock(&root->accounting_lock);
+ btrfs_set_root_used(&root->root_item,
+ btrfs_root_used(&root->root_item) - size);
+ spin_unlock(&root->accounting_lock);
+}
+
+/* given a node and slot number, this reads the blocks it points to. The
+ * extent buffer is returned with a reference taken (but unlocked).
+ * NULL is returned on error.
+ */
+static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
+ struct extent_buffer *parent, int slot)
+{
+ int level = btrfs_header_level(parent);
+ if (slot < 0)
+ return NULL;
+ if (slot >= btrfs_header_nritems(parent))
+ return NULL;
+
+ BUG_ON(level == 0);
+
+ return read_tree_block(root, btrfs_node_blockptr(parent, slot),
+ btrfs_level_size(root, level - 1),
+ btrfs_node_ptr_generation(parent, slot));
+}
+
+/*
+ * node level balancing, used to make sure nodes are in proper order for
+ * item deletion. We balance from the top down, so we have to make sure
+ * that a deletion won't leave an node completely empty later on.
+ */
+static noinline int balance_level(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ struct extent_buffer *right = NULL;
+ struct extent_buffer *mid;
+ struct extent_buffer *left = NULL;
+ struct extent_buffer *parent = NULL;
+ int ret = 0;
+ int wret;
+ int pslot;
+ int orig_slot = path->slots[level];
+ u64 orig_ptr;
+
+ if (level == 0)
+ return 0;
+
+ mid = path->nodes[level];
+
+ WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
+ path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
+ WARN_ON(btrfs_header_generation(mid) != trans->transid);
+
+ orig_ptr = btrfs_node_blockptr(mid, orig_slot);
+
+ if (level < BTRFS_MAX_LEVEL - 1) {
+ parent = path->nodes[level + 1];
+ pslot = path->slots[level + 1];
+ }
+
+ /*
+ * deal with the case where there is only one pointer in the root
+ * by promoting the node below to a root
+ */
+ if (!parent) {
+ struct extent_buffer *child;
+
+ if (btrfs_header_nritems(mid) != 1)
+ return 0;
+
+ /* promote the child to a root */
+ child = read_node_slot(root, mid, 0);
+ if (!child) {
+ ret = -EROFS;
+ btrfs_std_error(root->fs_info, ret);
+ goto enospc;
+ }
+
+ btrfs_tree_lock(child);
+ btrfs_set_lock_blocking(child);
+ ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
+ if (ret) {
+ btrfs_tree_unlock(child);
+ free_extent_buffer(child);
+ goto enospc;
+ }
+
+ rcu_assign_pointer(root->node, child);
+
+ add_root_to_dirty_list(root);
+ btrfs_tree_unlock(child);
+
+ path->locks[level] = 0;
+ path->nodes[level] = NULL;
+ clean_tree_block(trans, root, mid);
+ btrfs_tree_unlock(mid);
+ /* once for the path */
+ free_extent_buffer(mid);
+
+ root_sub_used(root, mid->len);
+ btrfs_free_tree_block(trans, root, mid, 0, 1, 0);
+ /* once for the root ptr */
+ free_extent_buffer_stale(mid);
+ return 0;
+ }
+ if (btrfs_header_nritems(mid) >
+ BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
+ return 0;
+
+ btrfs_header_nritems(mid);
+
+ left = read_node_slot(root, parent, pslot - 1);
+ if (left) {
+ btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
+ wret = btrfs_cow_block(trans, root, left,
+ parent, pslot - 1, &left);
+ if (wret) {
+ ret = wret;
+ goto enospc;
+ }
+ }
+ right = read_node_slot(root, parent, pslot + 1);
+ if (right) {
+ btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
+ wret = btrfs_cow_block(trans, root, right,
+ parent, pslot + 1, &right);
+ if (wret) {
+ ret = wret;
+ goto enospc;
+ }
+ }
+
+ /* first, try to make some room in the middle buffer */
+ if (left) {
+ orig_slot += btrfs_header_nritems(left);
+ wret = push_node_left(trans, root, left, mid, 1);
+ if (wret < 0)
+ ret = wret;
+ btrfs_header_nritems(mid);
+ }
+
+ /*
+ * then try to empty the right most buffer into the middle
+ */
+ if (right) {
+ wret = push_node_left(trans, root, mid, right, 1);
+ if (wret < 0 && wret != -ENOSPC)
+ ret = wret;
+ if (btrfs_header_nritems(right) == 0) {
+ clean_tree_block(trans, root, right);
+ btrfs_tree_unlock(right);
+ del_ptr(trans, root, path, level + 1, pslot + 1);
+ root_sub_used(root, right->len);
+ btrfs_free_tree_block(trans, root, right, 0, 1, 0);
+ free_extent_buffer_stale(right);
+ right = NULL;
+ } else {
+ struct btrfs_disk_key right_key;
+ btrfs_node_key(right, &right_key, 0);
+ btrfs_set_node_key(parent, &right_key, pslot + 1);
+ btrfs_mark_buffer_dirty(parent);
+ }
+ }
+ if (btrfs_header_nritems(mid) == 1) {
+ /*
+ * we're not allowed to leave a node with one item in the
+ * tree during a delete. A deletion from lower in the tree
+ * could try to delete the only pointer in this node.
+ * So, pull some keys from the left.
+ * There has to be a left pointer at this point because
+ * otherwise we would have pulled some pointers from the
+ * right
+ */
+ if (!left) {
+ ret = -EROFS;
+ btrfs_std_error(root->fs_info, ret);
+ goto enospc;
+ }
+ wret = balance_node_right(trans, root, mid, left);
+ if (wret < 0) {
+ ret = wret;
+ goto enospc;
+ }
+ if (wret == 1) {
+ wret = push_node_left(trans, root, left, mid, 1);
+ if (wret < 0)
+ ret = wret;
+ }
+ BUG_ON(wret == 1);
+ }
+ if (btrfs_header_nritems(mid) == 0) {
+ clean_tree_block(trans, root, mid);
+ btrfs_tree_unlock(mid);
+ del_ptr(trans, root, path, level + 1, pslot);
+ root_sub_used(root, mid->len);
+ btrfs_free_tree_block(trans, root, mid, 0, 1, 0);
+ free_extent_buffer_stale(mid);
+ mid = NULL;
+ } else {
+ /* update the parent key to reflect our changes */
+ struct btrfs_disk_key mid_key;
+ btrfs_node_key(mid, &mid_key, 0);
+ btrfs_set_node_key(parent, &mid_key, pslot);
+ btrfs_mark_buffer_dirty(parent);
+ }
+
+ /* update the path */
+ if (left) {
+ if (btrfs_header_nritems(left) > orig_slot) {
+ extent_buffer_get(left);
+ /* left was locked after cow */
+ path->nodes[level] = left;
+ path->slots[level + 1] -= 1;
+ path->slots[level] = orig_slot;
+ if (mid) {
+ btrfs_tree_unlock(mid);
+ free_extent_buffer(mid);
+ }
+ } else {
+ orig_slot -= btrfs_header_nritems(left);
+ path->slots[level] = orig_slot;
+ }
+ }
+ /* double check we haven't messed things up */
+ if (orig_ptr !=
+ btrfs_node_blockptr(path->nodes[level], path->slots[level]))
+ BUG();
+enospc:
+ if (right) {
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ if (left) {
+ if (path->nodes[level] != left)
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ }
+ return ret;
+}
+
+/* Node balancing for insertion. Here we only split or push nodes around
+ * when they are completely full. This is also done top down, so we
+ * have to be pessimistic.
+ */
+static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ struct extent_buffer *right = NULL;
+ struct extent_buffer *mid;
+ struct extent_buffer *left = NULL;
+ struct extent_buffer *parent = NULL;
+ int ret = 0;
+ int wret;
+ int pslot;
+ int orig_slot = path->slots[level];
+
+ if (level == 0)
+ return 1;
+
+ mid = path->nodes[level];
+ WARN_ON(btrfs_header_generation(mid) != trans->transid);
+
+ if (level < BTRFS_MAX_LEVEL - 1) {
+ parent = path->nodes[level + 1];
+ pslot = path->slots[level + 1];
+ }
+
+ if (!parent)
+ return 1;
+
+ left = read_node_slot(root, parent, pslot - 1);
+
+ /* first, try to make some room in the middle buffer */
+ if (left) {
+ u32 left_nr;
+
+ btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
+
+ left_nr = btrfs_header_nritems(left);
+ if (left_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
+ wret = 1;
+ } else {
+ ret = btrfs_cow_block(trans, root, left, parent,
+ pslot - 1, &left);
+ if (ret)
+ wret = 1;
+ else {
+ wret = push_node_left(trans, root,
+ left, mid, 0);
+ }
+ }
+ if (wret < 0)
+ ret = wret;
+ if (wret == 0) {
+ struct btrfs_disk_key disk_key;
+ orig_slot += left_nr;
+ btrfs_node_key(mid, &disk_key, 0);
+ btrfs_set_node_key(parent, &disk_key, pslot);
+ btrfs_mark_buffer_dirty(parent);
+ if (btrfs_header_nritems(left) > orig_slot) {
+ path->nodes[level] = left;
+ path->slots[level + 1] -= 1;
+ path->slots[level] = orig_slot;
+ btrfs_tree_unlock(mid);
+ free_extent_buffer(mid);
+ } else {
+ orig_slot -=
+ btrfs_header_nritems(left);
+ path->slots[level] = orig_slot;
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ }
+ return 0;
+ }
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ }
+ right = read_node_slot(root, parent, pslot + 1);
+
+ /*
+ * then try to empty the right most buffer into the middle
+ */
+ if (right) {
+ u32 right_nr;
+
+ btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
+
+ right_nr = btrfs_header_nritems(right);
+ if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(root) - 1) {
+ wret = 1;
+ } else {
+ ret = btrfs_cow_block(trans, root, right,
+ parent, pslot + 1,
+ &right);
+ if (ret)
+ wret = 1;
+ else {
+ wret = balance_node_right(trans, root,
+ right, mid);
+ }
+ }
+ if (wret < 0)
+ ret = wret;
+ if (wret == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_node_key(right, &disk_key, 0);
+ btrfs_set_node_key(parent, &disk_key, pslot + 1);
+ btrfs_mark_buffer_dirty(parent);
+
+ if (btrfs_header_nritems(mid) <= orig_slot) {
+ path->nodes[level] = right;
+ path->slots[level + 1] += 1;
+ path->slots[level] = orig_slot -
+ btrfs_header_nritems(mid);
+ btrfs_tree_unlock(mid);
+ free_extent_buffer(mid);
+ } else {
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ return 0;
+ }
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ return 1;
+}
+
+/*
+ * readahead one full node of leaves, finding things that are close
+ * to the block in 'slot', and triggering ra on them.
+ */
+static void reada_for_search(struct btrfs_root *root,
+ struct btrfs_path *path,
+ int level, int slot, u64 objectid)
+{
+ struct extent_buffer *node;
+ struct btrfs_disk_key disk_key;
+ u32 nritems;
+ u64 search;
+ u64 target;
+ u64 nread = 0;
+ u64 gen;
+ int direction = path->reada;
+ struct extent_buffer *eb;
+ u32 nr;
+ u32 blocksize;
+ u32 nscan = 0;
+
+ if (level != 1)
+ return;
+
+ if (!path->nodes[level])
+ return;
+
+ node = path->nodes[level];
+
+ search = btrfs_node_blockptr(node, slot);
+ blocksize = btrfs_level_size(root, level - 1);
+ eb = btrfs_find_tree_block(root, search, blocksize);
+ if (eb) {
+ free_extent_buffer(eb);
+ return;
+ }
+
+ target = search;
+
+ nritems = btrfs_header_nritems(node);
+ nr = slot;
+
+ while (1) {
+ if (direction < 0) {
+ if (nr == 0)
+ break;
+ nr--;
+ } else if (direction > 0) {
+ nr++;
+ if (nr >= nritems)
+ break;
+ }
+ if (path->reada < 0 && objectid) {
+ btrfs_node_key(node, &disk_key, nr);
+ if (btrfs_disk_key_objectid(&disk_key) != objectid)
+ break;
+ }
+ search = btrfs_node_blockptr(node, nr);
+ if ((search <= target && target - search <= 65536) ||
+ (search > target && search - target <= 65536)) {
+ gen = btrfs_node_ptr_generation(node, nr);
+ readahead_tree_block(root, search, blocksize, gen);
+ nread += blocksize;
+ }
+ nscan++;
+ if ((nread > 65536 || nscan > 32))
+ break;
+ }
+}
+
+/*
+ * returns -EAGAIN if it had to drop the path, or zero if everything was in
+ * cache
+ */
+static noinline int reada_for_balance(struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ int slot;
+ int nritems;
+ struct extent_buffer *parent;
+ struct extent_buffer *eb;
+ u64 gen;
+ u64 block1 = 0;
+ u64 block2 = 0;
+ int ret = 0;
+ int blocksize;
+
+ parent = path->nodes[level + 1];
+ if (!parent)
+ return 0;
+
+ nritems = btrfs_header_nritems(parent);
+ slot = path->slots[level + 1];
+ blocksize = btrfs_level_size(root, level);
+
+ if (slot > 0) {
+ block1 = btrfs_node_blockptr(parent, slot - 1);
+ gen = btrfs_node_ptr_generation(parent, slot - 1);
+ eb = btrfs_find_tree_block(root, block1, blocksize);
+ /*
+ * if we get -eagain from btrfs_buffer_uptodate, we
+ * don't want to return eagain here. That will loop
+ * forever
+ */
+ if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
+ block1 = 0;
+ free_extent_buffer(eb);
+ }
+ if (slot + 1 < nritems) {
+ block2 = btrfs_node_blockptr(parent, slot + 1);
+ gen = btrfs_node_ptr_generation(parent, slot + 1);
+ eb = btrfs_find_tree_block(root, block2, blocksize);
+ if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
+ block2 = 0;
+ free_extent_buffer(eb);
+ }
+ if (block1 || block2) {
+ ret = -EAGAIN;
+
+ /* release the whole path */
+ btrfs_release_path(path);
+
+ /* read the blocks */
+ if (block1)
+ readahead_tree_block(root, block1, blocksize, 0);
+ if (block2)
+ readahead_tree_block(root, block2, blocksize, 0);
+
+ if (block1) {
+ eb = read_tree_block(root, block1, blocksize, 0);
+ free_extent_buffer(eb);
+ }
+ if (block2) {
+ eb = read_tree_block(root, block2, blocksize, 0);
+ free_extent_buffer(eb);
+ }
+ }
+ return ret;
+}
+
+
+/*
+ * when we walk down the tree, it is usually safe to unlock the higher layers
+ * in the tree. The exceptions are when our path goes through slot 0, because
+ * operations on the tree might require changing key pointers higher up in the
+ * tree.
+ *
+ * callers might also have set path->keep_locks, which tells this code to keep
+ * the lock if the path points to the last slot in the block. This is part of
+ * walking through the tree, and selecting the next slot in the higher block.
+ *
+ * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
+ * if lowest_unlock is 1, level 0 won't be unlocked
+ */
+static noinline void unlock_up(struct btrfs_path *path, int level,
+ int lowest_unlock, int min_write_lock_level,
+ int *write_lock_level)
+{
+ int i;
+ int skip_level = level;
+ int no_skips = 0;
+ struct extent_buffer *t;
+
+ for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+ if (!path->nodes[i])
+ break;
+ if (!path->locks[i])
+ break;
+ if (!no_skips && path->slots[i] == 0) {
+ skip_level = i + 1;
+ continue;
+ }
+ if (!no_skips && path->keep_locks) {
+ u32 nritems;
+ t = path->nodes[i];
+ nritems = btrfs_header_nritems(t);
+ if (nritems < 1 || path->slots[i] >= nritems - 1) {
+ skip_level = i + 1;
+ continue;
+ }
+ }
+ if (skip_level < i && i >= lowest_unlock)
+ no_skips = 1;
+
+ t = path->nodes[i];
+ if (i >= lowest_unlock && i > skip_level && path->locks[i]) {
+ btrfs_tree_unlock_rw(t, path->locks[i]);
+ path->locks[i] = 0;
+ if (write_lock_level &&
+ i > min_write_lock_level &&
+ i <= *write_lock_level) {
+ *write_lock_level = i - 1;
+ }
+ }
+ }
+}
+
+/*
+ * This releases any locks held in the path starting at level and
+ * going all the way up to the root.
+ *
+ * btrfs_search_slot will keep the lock held on higher nodes in a few
+ * corner cases, such as COW of the block at slot zero in the node. This
+ * ignores those rules, and it should only be called when there are no
+ * more updates to be done higher up in the tree.
+ */
+noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
+{
+ int i;
+
+ if (path->keep_locks)
+ return;
+
+ for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+ if (!path->nodes[i])
+ continue;
+ if (!path->locks[i])
+ continue;
+ btrfs_tree_unlock_rw(path->nodes[i], path->locks[i]);
+ path->locks[i] = 0;
+ }
+}
+
+/*
+ * helper function for btrfs_search_slot. The goal is to find a block
+ * in cache without setting the path to blocking. If we find the block
+ * we return zero and the path is unchanged.
+ *
+ * If we can't find the block, we set the path blocking and do some
+ * reada. -EAGAIN is returned and the search must be repeated.
+ */
+static int
+read_block_for_search(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *p,
+ struct extent_buffer **eb_ret, int level, int slot,
+ struct btrfs_key *key)
+{
+ u64 blocknr;
+ u64 gen;
+ u32 blocksize;
+ struct extent_buffer *b = *eb_ret;
+ struct extent_buffer *tmp;
+ int ret;
+
+ blocknr = btrfs_node_blockptr(b, slot);
+ gen = btrfs_node_ptr_generation(b, slot);
+ blocksize = btrfs_level_size(root, level - 1);
+
+ tmp = btrfs_find_tree_block(root, blocknr, blocksize);
+ if (tmp) {
+ /* first we do an atomic uptodate check */
+ if (btrfs_buffer_uptodate(tmp, 0, 1) > 0) {
+ if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
+ /*
+ * we found an up to date block without
+ * sleeping, return
+ * right away
+ */
+ *eb_ret = tmp;
+ return 0;
+ }
+ /* the pages were up to date, but we failed
+ * the generation number check. Do a full
+ * read for the generation number that is correct.
+ * We must do this without dropping locks so
+ * we can trust our generation number
+ */
+ free_extent_buffer(tmp);
+ btrfs_set_path_blocking(p);
+
+ /* now we're allowed to do a blocking uptodate check */
+ tmp = read_tree_block(root, blocknr, blocksize, gen);
+ if (tmp && btrfs_buffer_uptodate(tmp, gen, 0) > 0) {
+ *eb_ret = tmp;
+ return 0;
+ }
+ free_extent_buffer(tmp);
+ btrfs_release_path(p);
+ return -EIO;
+ }
+ }
+
+ /*
+ * reduce lock contention at high levels
+ * of the btree by dropping locks before
+ * we read. Don't release the lock on the current
+ * level because we need to walk this node to figure
+ * out which blocks to read.
+ */
+ btrfs_unlock_up_safe(p, level + 1);
+ btrfs_set_path_blocking(p);
+
+ free_extent_buffer(tmp);
+ if (p->reada)
+ reada_for_search(root, p, level, slot, key->objectid);
+
+ btrfs_release_path(p);
+
+ ret = -EAGAIN;
+ tmp = read_tree_block(root, blocknr, blocksize, 0);
+ if (tmp) {
+ /*
+ * If the read above didn't mark this buffer up to date,
+ * it will never end up being up to date. Set ret to EIO now
+ * and give up so that our caller doesn't loop forever
+ * on our EAGAINs.
+ */
+ if (!btrfs_buffer_uptodate(tmp, 0, 0))
+ ret = -EIO;
+ free_extent_buffer(tmp);
+ }
+ return ret;
+}
+
+/*
+ * helper function for btrfs_search_slot. This does all of the checks
+ * for node-level blocks and does any balancing required based on
+ * the ins_len.
+ *
+ * If no extra work was required, zero is returned. If we had to
+ * drop the path, -EAGAIN is returned and btrfs_search_slot must
+ * start over
+ */
+static int
+setup_nodes_for_search(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *p,
+ struct extent_buffer *b, int level, int ins_len,
+ int *write_lock_level)
+{
+ int ret;
+ if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
+ BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
+ int sret;
+
+ if (*write_lock_level < level + 1) {
+ *write_lock_level = level + 1;
+ btrfs_release_path(p);
+ goto again;
+ }
+
+ sret = reada_for_balance(root, p, level);
+ if (sret)
+ goto again;
+
+ btrfs_set_path_blocking(p);
+ sret = split_node(trans, root, p, level);
+ btrfs_clear_path_blocking(p, NULL, 0);
+
+ BUG_ON(sret > 0);
+ if (sret) {
+ ret = sret;
+ goto done;
+ }
+ b = p->nodes[level];
+ } else if (ins_len < 0 && btrfs_header_nritems(b) <
+ BTRFS_NODEPTRS_PER_BLOCK(root) / 2) {
+ int sret;
+
+ if (*write_lock_level < level + 1) {
+ *write_lock_level = level + 1;
+ btrfs_release_path(p);
+ goto again;
+ }
+
+ sret = reada_for_balance(root, p, level);
+ if (sret)
+ goto again;
+
+ btrfs_set_path_blocking(p);
+ sret = balance_level(trans, root, p, level);
+ btrfs_clear_path_blocking(p, NULL, 0);
+
+ if (sret) {
+ ret = sret;
+ goto done;
+ }
+ b = p->nodes[level];
+ if (!b) {
+ btrfs_release_path(p);
+ goto again;
+ }
+ BUG_ON(btrfs_header_nritems(b) == 1);
+ }
+ return 0;
+
+again:
+ ret = -EAGAIN;
+done:
+ return ret;
+}
+
+/*
+ * look for key in the tree. path is filled in with nodes along the way
+ * if key is found, we return zero and you can find the item in the leaf
+ * level of the path (level 0)
+ *
+ * If the key isn't found, the path points to the slot where it should
+ * be inserted, and 1 is returned. If there are other errors during the
+ * search a negative error number is returned.
+ *
+ * if ins_len > 0, nodes and leaves will be split as we walk down the
+ * tree. if ins_len < 0, nodes will be merged as we walk down the tree (if
+ * possible)
+ */
+int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *key, struct btrfs_path *p, int
+ ins_len, int cow)
+{
+ struct extent_buffer *b;
+ int slot;
+ int ret;
+ int err;
+ int level;
+ int lowest_unlock = 1;
+ int root_lock;
+ /* everything at write_lock_level or lower must be write locked */
+ int write_lock_level = 0;
+ u8 lowest_level = 0;
+ int min_write_lock_level;
+
+ lowest_level = p->lowest_level;
+ WARN_ON(lowest_level && ins_len > 0);
+ WARN_ON(p->nodes[0] != NULL);
+
+ if (ins_len < 0) {
+ lowest_unlock = 2;
+
+ /* when we are removing items, we might have to go up to level
+ * two as we update tree pointers Make sure we keep write
+ * for those levels as well
+ */
+ write_lock_level = 2;
+ } else if (ins_len > 0) {
+ /*
+ * for inserting items, make sure we have a write lock on
+ * level 1 so we can update keys
+ */
+ write_lock_level = 1;
+ }
+
+ if (!cow)
+ write_lock_level = -1;
+
+ if (cow && (p->keep_locks || p->lowest_level))
+ write_lock_level = BTRFS_MAX_LEVEL;
+
+ min_write_lock_level = write_lock_level;
+
+again:
+ /*
+ * we try very hard to do read locks on the root
+ */
+ root_lock = BTRFS_READ_LOCK;
+ level = 0;
+ if (p->search_commit_root) {
+ /*
+ * the commit roots are read only
+ * so we always do read locks
+ */
+ b = root->commit_root;
+ extent_buffer_get(b);
+ level = btrfs_header_level(b);
+ if (!p->skip_locking)
+ btrfs_tree_read_lock(b);
+ } else {
+ if (p->skip_locking) {
+ b = btrfs_root_node(root);
+ level = btrfs_header_level(b);
+ } else {
+ /* we don't know the level of the root node
+ * until we actually have it read locked
+ */
+ b = btrfs_read_lock_root_node(root);
+ level = btrfs_header_level(b);
+ if (level <= write_lock_level) {
+ /* whoops, must trade for write lock */
+ btrfs_tree_read_unlock(b);
+ free_extent_buffer(b);
+ b = btrfs_lock_root_node(root);
+ root_lock = BTRFS_WRITE_LOCK;
+
+ /* the level might have changed, check again */
+ level = btrfs_header_level(b);
+ }
+ }
+ }
+ p->nodes[level] = b;
+ if (!p->skip_locking)
+ p->locks[level] = root_lock;
+
+ while (b) {
+ level = btrfs_header_level(b);
+
+ /*
+ * setup the path here so we can release it under lock
+ * contention with the cow code
+ */
+ if (cow) {
+ /*
+ * if we don't really need to cow this block
+ * then we don't want to set the path blocking,
+ * so we test it here
+ */
+ if (!should_cow_block(trans, root, b))
+ goto cow_done;
+
+ btrfs_set_path_blocking(p);
+
+ /*
+ * must have write locks on this node and the
+ * parent
+ */
+ if (level + 1 > write_lock_level) {
+ write_lock_level = level + 1;
+ btrfs_release_path(p);
+ goto again;
+ }
+
+ err = btrfs_cow_block(trans, root, b,
+ p->nodes[level + 1],
+ p->slots[level + 1], &b);
+ if (err) {
+ ret = err;
+ goto done;
+ }
+ }
+cow_done:
+ BUG_ON(!cow && ins_len);
+
+ p->nodes[level] = b;
+ btrfs_clear_path_blocking(p, NULL, 0);
+
+ /*
+ * we have a lock on b and as long as we aren't changing
+ * the tree, there is no way to for the items in b to change.
+ * It is safe to drop the lock on our parent before we
+ * go through the expensive btree search on b.
+ *
+ * If cow is true, then we might be changing slot zero,
+ * which may require changing the parent. So, we can't
+ * drop the lock until after we know which slot we're
+ * operating on.
+ */
+ if (!cow)
+ btrfs_unlock_up_safe(p, level + 1);
+
+ ret = bin_search(b, key, level, &slot);
+
+ if (level != 0) {
+ int dec = 0;
+ if (ret && slot > 0) {
+ dec = 1;
+ slot -= 1;
+ }
+ p->slots[level] = slot;
+ err = setup_nodes_for_search(trans, root, p, b, level,
+ ins_len, &write_lock_level);
+ if (err == -EAGAIN)
+ goto again;
+ if (err) {
+ ret = err;
+ goto done;
+ }
+ b = p->nodes[level];
+ slot = p->slots[level];
+
+ /*
+ * slot 0 is special, if we change the key
+ * we have to update the parent pointer
+ * which means we must have a write lock
+ * on the parent
+ */
+ if (slot == 0 && cow &&
+ write_lock_level < level + 1) {
+ write_lock_level = level + 1;
+ btrfs_release_path(p);
+ goto again;
+ }
+
+ unlock_up(p, level, lowest_unlock,
+ min_write_lock_level, &write_lock_level);
+
+ if (level == lowest_level) {
+ if (dec)
+ p->slots[level]++;
+ goto done;
+ }
+
+ err = read_block_for_search(trans, root, p,
+ &b, level, slot, key);
+ if (err == -EAGAIN)
+ goto again;
+ if (err) {
+ ret = err;
+ goto done;
+ }
+
+ if (!p->skip_locking) {
+ level = btrfs_header_level(b);
+ if (level <= write_lock_level) {
+ err = btrfs_try_tree_write_lock(b);
+ if (!err) {
+ btrfs_set_path_blocking(p);
+ btrfs_tree_lock(b);
+ btrfs_clear_path_blocking(p, b,
+ BTRFS_WRITE_LOCK);
+ }
+ p->locks[level] = BTRFS_WRITE_LOCK;
+ } else {
+ err = btrfs_try_tree_read_lock(b);
+ if (!err) {
+ btrfs_set_path_blocking(p);
+ btrfs_tree_read_lock(b);
+ btrfs_clear_path_blocking(p, b,
+ BTRFS_READ_LOCK);
+ }
+ p->locks[level] = BTRFS_READ_LOCK;
+ }
+ p->nodes[level] = b;
+ }
+ } else {
+ p->slots[level] = slot;
+ if (ins_len > 0 &&
+ btrfs_leaf_free_space(root, b) < ins_len) {
+ if (write_lock_level < 1) {
+ write_lock_level = 1;
+ btrfs_release_path(p);
+ goto again;
+ }
+
+ btrfs_set_path_blocking(p);
+ err = split_leaf(trans, root, key,
+ p, ins_len, ret == 0);
+ btrfs_clear_path_blocking(p, NULL, 0);
+
+ BUG_ON(err > 0);
+ if (err) {
+ ret = err;
+ goto done;
+ }
+ }
+ if (!p->search_for_split)
+ unlock_up(p, level, lowest_unlock,
+ min_write_lock_level, &write_lock_level);
+ goto done;
+ }
+ }
+ ret = 1;
+done:
+ /*
+ * we don't really know what they plan on doing with the path
+ * from here on, so for now just mark it as blocking
+ */
+ if (!p->leave_spinning)
+ btrfs_set_path_blocking(p);
+ if (ret < 0)
+ btrfs_release_path(p);
+ return ret;
+}
+
+/*
+ * adjust the pointers going up the tree, starting at level
+ * making sure the right key of each node is points to 'key'.
+ * This is used after shifting pointers to the left, so it stops
+ * fixing up pointers when a given leaf/node is not in slot 0 of the
+ * higher levels
+ *
+ */
+static void fixup_low_keys(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_disk_key *key, int level)
+{
+ int i;
+ struct extent_buffer *t;
+
+ for (i = level; i < BTRFS_MAX_LEVEL; i++) {
+ int tslot = path->slots[i];
+ if (!path->nodes[i])
+ break;
+ t = path->nodes[i];
+ btrfs_set_node_key(t, key, tslot);
+ btrfs_mark_buffer_dirty(path->nodes[i]);
+ if (tslot != 0)
+ break;
+ }
+}
+
+/*
+ * update item key.
+ *
+ * This function isn't completely safe. It's the caller's responsibility
+ * that the new key won't break the order
+ */
+void btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *new_key)
+{
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *eb;
+ int slot;
+
+ eb = path->nodes[0];
+ slot = path->slots[0];
+ if (slot > 0) {
+ btrfs_item_key(eb, &disk_key, slot - 1);
+ BUG_ON(comp_keys(&disk_key, new_key) >= 0);
+ }
+ if (slot < btrfs_header_nritems(eb) - 1) {
+ btrfs_item_key(eb, &disk_key, slot + 1);
+ BUG_ON(comp_keys(&disk_key, new_key) <= 0);
+ }
+
+ btrfs_cpu_key_to_disk(&disk_key, new_key);
+ btrfs_set_item_key(eb, &disk_key, slot);
+ btrfs_mark_buffer_dirty(eb);
+ if (slot == 0)
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+}
+
+/*
+ * try to push data from one node into the next node left in the
+ * tree.
+ *
+ * returns 0 if some ptrs were pushed left, < 0 if there was some horrible
+ * error, and > 0 if there was no room in the left hand block.
+ */
+static int push_node_left(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct extent_buffer *dst,
+ struct extent_buffer *src, int empty)
+{
+ int push_items = 0;
+ int src_nritems;
+ int dst_nritems;
+ int ret = 0;
+
+ src_nritems = btrfs_header_nritems(src);
+ dst_nritems = btrfs_header_nritems(dst);
+ push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
+ WARN_ON(btrfs_header_generation(src) != trans->transid);
+ WARN_ON(btrfs_header_generation(dst) != trans->transid);
+
+ if (!empty && src_nritems <= 8)
+ return 1;
+
+ if (push_items <= 0)
+ return 1;
+
+ if (empty) {
+ push_items = min(src_nritems, push_items);
+ if (push_items < src_nritems) {
+ /* leave at least 8 pointers in the node if
+ * we aren't going to empty it
+ */
+ if (src_nritems - push_items < 8) {
+ if (push_items <= 8)
+ return 1;
+ push_items -= 8;
+ }
+ }
+ } else
+ push_items = min(src_nritems - 8, push_items);
+
+ copy_extent_buffer(dst, src,
+ btrfs_node_key_ptr_offset(dst_nritems),
+ btrfs_node_key_ptr_offset(0),
+ push_items * sizeof(struct btrfs_key_ptr));
+
+ if (push_items < src_nritems) {
+ memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
+ btrfs_node_key_ptr_offset(push_items),
+ (src_nritems - push_items) *
+ sizeof(struct btrfs_key_ptr));
+ }
+ btrfs_set_header_nritems(src, src_nritems - push_items);
+ btrfs_set_header_nritems(dst, dst_nritems + push_items);
+ btrfs_mark_buffer_dirty(src);
+ btrfs_mark_buffer_dirty(dst);
+
+ return ret;
+}
+
+/*
+ * try to push data from one node into the next node right in the
+ * tree.
+ *
+ * returns 0 if some ptrs were pushed, < 0 if there was some horrible
+ * error, and > 0 if there was no room in the right hand block.
+ *
+ * this will only push up to 1/2 the contents of the left node over
+ */
+static int balance_node_right(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct extent_buffer *dst,
+ struct extent_buffer *src)
+{
+ int push_items = 0;
+ int max_push;
+ int src_nritems;
+ int dst_nritems;
+ int ret = 0;
+
+ WARN_ON(btrfs_header_generation(src) != trans->transid);
+ WARN_ON(btrfs_header_generation(dst) != trans->transid);
+
+ src_nritems = btrfs_header_nritems(src);
+ dst_nritems = btrfs_header_nritems(dst);
+ push_items = BTRFS_NODEPTRS_PER_BLOCK(root) - dst_nritems;
+ if (push_items <= 0)
+ return 1;
+
+ if (src_nritems < 4)
+ return 1;
+
+ max_push = src_nritems / 2 + 1;
+ /* don't try to empty the node */
+ if (max_push >= src_nritems)
+ return 1;
+
+ if (max_push < push_items)
+ push_items = max_push;
+
+ memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
+ btrfs_node_key_ptr_offset(0),
+ (dst_nritems) *
+ sizeof(struct btrfs_key_ptr));
+
+ copy_extent_buffer(dst, src,
+ btrfs_node_key_ptr_offset(0),
+ btrfs_node_key_ptr_offset(src_nritems - push_items),
+ push_items * sizeof(struct btrfs_key_ptr));
+
+ btrfs_set_header_nritems(src, src_nritems - push_items);
+ btrfs_set_header_nritems(dst, dst_nritems + push_items);
+
+ btrfs_mark_buffer_dirty(src);
+ btrfs_mark_buffer_dirty(dst);
+
+ return ret;
+}
+
+/*
+ * helper function to insert a new root level in the tree.
+ * A new node is allocated, and a single item is inserted to
+ * point to the existing root
+ *
+ * returns zero on success or < 0 on failure.
+ */
+static noinline int insert_new_root(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ u64 lower_gen;
+ struct extent_buffer *lower;
+ struct extent_buffer *c;
+ struct extent_buffer *old;
+ struct btrfs_disk_key lower_key;
+
+ BUG_ON(path->nodes[level]);
+ BUG_ON(path->nodes[level-1] != root->node);
+
+ lower = path->nodes[level-1];
+ if (level == 1)
+ btrfs_item_key(lower, &lower_key, 0);
+ else
+ btrfs_node_key(lower, &lower_key, 0);
+
+ c = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
+ root->root_key.objectid, &lower_key,
+ level, root->node->start, 0, 0);
+ if (IS_ERR(c))
+ return PTR_ERR(c);
+
+ root_add_used(root, root->nodesize);
+
+ memset_extent_buffer(c, 0, 0, sizeof(struct btrfs_header));
+ btrfs_set_header_nritems(c, 1);
+ btrfs_set_header_level(c, level);
+ btrfs_set_header_bytenr(c, c->start);
+ btrfs_set_header_generation(c, trans->transid);
+ btrfs_set_header_backref_rev(c, BTRFS_MIXED_BACKREF_REV);
+ btrfs_set_header_owner(c, root->root_key.objectid);
+
+ write_extent_buffer(c, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(c),
+ BTRFS_FSID_SIZE);
+
+ write_extent_buffer(c, root->fs_info->chunk_tree_uuid,
+ (unsigned long)btrfs_header_chunk_tree_uuid(c),
+ BTRFS_UUID_SIZE);
+
+ btrfs_set_node_key(c, &lower_key, 0);
+ btrfs_set_node_blockptr(c, 0, lower->start);
+ lower_gen = btrfs_header_generation(lower);
+ WARN_ON(lower_gen != trans->transid);
+
+ btrfs_set_node_ptr_generation(c, 0, lower_gen);
+
+ btrfs_mark_buffer_dirty(c);
+
+ old = root->node;
+ rcu_assign_pointer(root->node, c);
+
+ /* the super has an extra ref to root->node */
+ free_extent_buffer(old);
+
+ add_root_to_dirty_list(root);
+ extent_buffer_get(c);
+ path->nodes[level] = c;
+ path->locks[level] = BTRFS_WRITE_LOCK;
+ path->slots[level] = 0;
+ return 0;
+}
+
+/*
+ * worker function to insert a single pointer in a node.
+ * the node should have enough room for the pointer already
+ *
+ * slot and level indicate where you want the key to go, and
+ * blocknr is the block the key points to.
+ */
+static void insert_ptr(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_disk_key *key, u64 bytenr,
+ int slot, int level)
+{
+ struct extent_buffer *lower;
+ int nritems;
+
+ BUG_ON(!path->nodes[level]);
+ btrfs_assert_tree_locked(path->nodes[level]);
+ lower = path->nodes[level];
+ nritems = btrfs_header_nritems(lower);
+ BUG_ON(slot > nritems);
+ BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(root));
+ if (slot != nritems) {
+ memmove_extent_buffer(lower,
+ btrfs_node_key_ptr_offset(slot + 1),
+ btrfs_node_key_ptr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_key_ptr));
+ }
+ btrfs_set_node_key(lower, key, slot);
+ btrfs_set_node_blockptr(lower, slot, bytenr);
+ WARN_ON(trans->transid == 0);
+ btrfs_set_node_ptr_generation(lower, slot, trans->transid);
+ btrfs_set_header_nritems(lower, nritems + 1);
+ btrfs_mark_buffer_dirty(lower);
+}
+
+/*
+ * split the node at the specified level in path in two.
+ * The path is corrected to point to the appropriate node after the split
+ *
+ * Before splitting this tries to make some room in the node by pushing
+ * left and right, if either one works, it returns right away.
+ *
+ * returns 0 on success and < 0 on failure
+ */
+static noinline int split_node(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int level)
+{
+ struct extent_buffer *c;
+ struct extent_buffer *split;
+ struct btrfs_disk_key disk_key;
+ int mid;
+ int ret;
+ u32 c_nritems;
+
+ c = path->nodes[level];
+ WARN_ON(btrfs_header_generation(c) != trans->transid);
+ if (c == root->node) {
+ /* trying to split the root, lets make a new one */
+ ret = insert_new_root(trans, root, path, level + 1);
+ if (ret)
+ return ret;
+ } else {
+ ret = push_nodes_for_insert(trans, root, path, level);
+ c = path->nodes[level];
+ if (!ret && btrfs_header_nritems(c) <
+ BTRFS_NODEPTRS_PER_BLOCK(root) - 3)
+ return 0;
+ if (ret < 0)
+ return ret;
+ }
+
+ c_nritems = btrfs_header_nritems(c);
+ mid = (c_nritems + 1) / 2;
+ btrfs_node_key(c, &disk_key, mid);
+
+ split = btrfs_alloc_free_block(trans, root, root->nodesize, 0,
+ root->root_key.objectid,
+ &disk_key, level, c->start, 0, 0);
+ if (IS_ERR(split))
+ return PTR_ERR(split);
+
+ root_add_used(root, root->nodesize);
+
+ memset_extent_buffer(split, 0, 0, sizeof(struct btrfs_header));
+ btrfs_set_header_level(split, btrfs_header_level(c));
+ btrfs_set_header_bytenr(split, split->start);
+ btrfs_set_header_generation(split, trans->transid);
+ btrfs_set_header_backref_rev(split, BTRFS_MIXED_BACKREF_REV);
+ btrfs_set_header_owner(split, root->root_key.objectid);
+ write_extent_buffer(split, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(split),
+ BTRFS_FSID_SIZE);
+ write_extent_buffer(split, root->fs_info->chunk_tree_uuid,
+ (unsigned long)btrfs_header_chunk_tree_uuid(split),
+ BTRFS_UUID_SIZE);
+
+
+ copy_extent_buffer(split, c,
+ btrfs_node_key_ptr_offset(0),
+ btrfs_node_key_ptr_offset(mid),
+ (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
+ btrfs_set_header_nritems(split, c_nritems - mid);
+ btrfs_set_header_nritems(c, mid);
+ ret = 0;
+
+ btrfs_mark_buffer_dirty(c);
+ btrfs_mark_buffer_dirty(split);
+
+ insert_ptr(trans, root, path, &disk_key, split->start,
+ path->slots[level + 1] + 1, level + 1);
+
+ if (path->slots[level] >= mid) {
+ path->slots[level] -= mid;
+ btrfs_tree_unlock(c);
+ free_extent_buffer(c);
+ path->nodes[level] = split;
+ path->slots[level + 1] += 1;
+ } else {
+ btrfs_tree_unlock(split);
+ free_extent_buffer(split);
+ }
+ return ret;
+}
+
+/*
+ * how many bytes are required to store the items in a leaf. start
+ * and nr indicate which items in the leaf to check. This totals up the
+ * space used both by the item structs and the item data
+ */
+static int leaf_space_used(struct extent_buffer *l, int start, int nr)
+{
+ int data_len;
+ int nritems = btrfs_header_nritems(l);
+ int end = min(nritems, start + nr) - 1;
+
+ if (!nr)
+ return 0;
+ data_len = btrfs_item_end_nr(l, start);
+ data_len = data_len - btrfs_item_offset_nr(l, end);
+ data_len += sizeof(struct btrfs_item) * nr;
+ WARN_ON(data_len < 0);
+ return data_len;
+}
+
+/*
+ * The space between the end of the leaf items and
+ * the start of the leaf data. IOW, how much room
+ * the leaf has left for both items and data
+ */
+noinline int btrfs_leaf_free_space(struct btrfs_root *root,
+ struct extent_buffer *leaf)
+{
+ int nritems = btrfs_header_nritems(leaf);
+ int ret;
+ ret = BTRFS_LEAF_DATA_SIZE(root) - leaf_space_used(leaf, 0, nritems);
+ if (ret < 0) {
+ printk(KERN_CRIT "leaf free space ret %d, leaf data size %lu, "
+ "used %d nritems %d\n",
+ ret, (unsigned long) BTRFS_LEAF_DATA_SIZE(root),
+ leaf_space_used(leaf, 0, nritems), nritems);
+ }
+ return ret;
+}
+
+/*
+ * min slot controls the lowest index we're willing to push to the
+ * right. We'll push up to and including min_slot, but no lower
+ */
+static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ int data_size, int empty,
+ struct extent_buffer *right,
+ int free_space, u32 left_nritems,
+ u32 min_slot)
+{
+ struct extent_buffer *left = path->nodes[0];
+ struct extent_buffer *upper = path->nodes[1];
+ struct btrfs_map_token token;
+ struct btrfs_disk_key disk_key;
+ int slot;
+ u32 i;
+ int push_space = 0;
+ int push_items = 0;
+ struct btrfs_item *item;
+ u32 nr;
+ u32 right_nritems;
+ u32 data_end;
+ u32 this_item_size;
+
+ btrfs_init_map_token(&token);
+
+ if (empty)
+ nr = 0;
+ else
+ nr = max_t(u32, 1, min_slot);
+
+ if (path->slots[0] >= left_nritems)
+ push_space += data_size;
+
+ slot = path->slots[1];
+ i = left_nritems - 1;
+ while (i >= nr) {
+ item = btrfs_item_nr(left, i);
+
+ if (!empty && push_items > 0) {
+ if (path->slots[0] > i)
+ break;
+ if (path->slots[0] == i) {
+ int space = btrfs_leaf_free_space(root, left);
+ if (space + push_space * 2 > free_space)
+ break;
+ }
+ }
+
+ if (path->slots[0] == i)
+ push_space += data_size;
+
+ this_item_size = btrfs_item_size(left, item);
+ if (this_item_size + sizeof(*item) + push_space > free_space)
+ break;
+
+ push_items++;
+ push_space += this_item_size + sizeof(*item);
+ if (i == 0)
+ break;
+ i--;
+ }
+
+ if (push_items == 0)
+ goto out_unlock;
+
+ if (!empty && push_items == left_nritems)
+ WARN_ON(1);
+
+ /* push left to right */
+ right_nritems = btrfs_header_nritems(right);
+
+ push_space = btrfs_item_end_nr(left, left_nritems - push_items);
+ push_space -= leaf_data_end(root, left);
+
+ /* make room in the right data area */
+ data_end = leaf_data_end(root, right);
+ memmove_extent_buffer(right,
+ btrfs_leaf_data(right) + data_end - push_space,
+ btrfs_leaf_data(right) + data_end,
+ BTRFS_LEAF_DATA_SIZE(root) - data_end);
+
+ /* copy from the left data area */
+ copy_extent_buffer(right, left, btrfs_leaf_data(right) +
+ BTRFS_LEAF_DATA_SIZE(root) - push_space,
+ btrfs_leaf_data(left) + leaf_data_end(root, left),
+ push_space);
+
+ memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
+ btrfs_item_nr_offset(0),
+ right_nritems * sizeof(struct btrfs_item));
+
+ /* copy the items from left to right */
+ copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
+ btrfs_item_nr_offset(left_nritems - push_items),
+ push_items * sizeof(struct btrfs_item));
+
+ /* update the item pointers */
+ right_nritems += push_items;
+ btrfs_set_header_nritems(right, right_nritems);
+ push_space = BTRFS_LEAF_DATA_SIZE(root);
+ for (i = 0; i < right_nritems; i++) {
+ item = btrfs_item_nr(right, i);
+ push_space -= btrfs_token_item_size(right, item, &token);
+ btrfs_set_token_item_offset(right, item, push_space, &token);
+ }
+
+ left_nritems -= push_items;
+ btrfs_set_header_nritems(left, left_nritems);
+
+ if (left_nritems)
+ btrfs_mark_buffer_dirty(left);
+ else
+ clean_tree_block(trans, root, left);
+
+ btrfs_mark_buffer_dirty(right);
+
+ btrfs_item_key(right, &disk_key, 0);
+ btrfs_set_node_key(upper, &disk_key, slot + 1);
+ btrfs_mark_buffer_dirty(upper);
+
+ /* then fixup the leaf pointer in the path */
+ if (path->slots[0] >= left_nritems) {
+ path->slots[0] -= left_nritems;
+ if (btrfs_header_nritems(path->nodes[0]) == 0)
+ clean_tree_block(trans, root, path->nodes[0]);
+ btrfs_tree_unlock(path->nodes[0]);
+ free_extent_buffer(path->nodes[0]);
+ path->nodes[0] = right;
+ path->slots[1] += 1;
+ } else {
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+ return 0;
+
+out_unlock:
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ return 1;
+}
+
+/*
+ * push some data in the path leaf to the right, trying to free up at
+ * least data_size bytes. returns zero if the push worked, nonzero otherwise
+ *
+ * returns 1 if the push failed because the other node didn't have enough
+ * room, 0 if everything worked out and < 0 if there were major errors.
+ *
+ * this will push starting from min_slot to the end of the leaf. It won't
+ * push any slot lower than min_slot
+ */
+static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_path *path,
+ int min_data_size, int data_size,
+ int empty, u32 min_slot)
+{
+ struct extent_buffer *left = path->nodes[0];
+ struct extent_buffer *right;
+ struct extent_buffer *upper;
+ int slot;
+ int free_space;
+ u32 left_nritems;
+ int ret;
+
+ if (!path->nodes[1])
+ return 1;
+
+ slot = path->slots[1];
+ upper = path->nodes[1];
+ if (slot >= btrfs_header_nritems(upper) - 1)
+ return 1;
+
+ btrfs_assert_tree_locked(path->nodes[1]);
+
+ right = read_node_slot(root, upper, slot + 1);
+ if (right == NULL)
+ return 1;
+
+ btrfs_tree_lock(right);
+ btrfs_set_lock_blocking(right);
+
+ free_space = btrfs_leaf_free_space(root, right);
+ if (free_space < data_size)
+ goto out_unlock;
+
+ /* cow and double check */
+ ret = btrfs_cow_block(trans, root, right, upper,
+ slot + 1, &right);
+ if (ret)
+ goto out_unlock;
+
+ free_space = btrfs_leaf_free_space(root, right);
+ if (free_space < data_size)
+ goto out_unlock;
+
+ left_nritems = btrfs_header_nritems(left);
+ if (left_nritems == 0)
+ goto out_unlock;
+
+ return __push_leaf_right(trans, root, path, min_data_size, empty,
+ right, free_space, left_nritems, min_slot);
+out_unlock:
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ return 1;
+}
+
+/*
+ * push some data in the path leaf to the left, trying to free up at
+ * least data_size bytes. returns zero if the push worked, nonzero otherwise
+ *
+ * max_slot can put a limit on how far into the leaf we'll push items. The
+ * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
+ * items
+ */
+static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int data_size,
+ int empty, struct extent_buffer *left,
+ int free_space, u32 right_nritems,
+ u32 max_slot)
+{
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *right = path->nodes[0];
+ int i;
+ int push_space = 0;
+ int push_items = 0;
+ struct btrfs_item *item;
+ u32 old_left_nritems;
+ u32 nr;
+ int ret = 0;
+ u32 this_item_size;
+ u32 old_left_item_size;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ if (empty)
+ nr = min(right_nritems, max_slot);
+ else
+ nr = min(right_nritems - 1, max_slot);
+
+ for (i = 0; i < nr; i++) {
+ item = btrfs_item_nr(right, i);
+
+ if (!empty && push_items > 0) {
+ if (path->slots[0] < i)
+ break;
+ if (path->slots[0] == i) {
+ int space = btrfs_leaf_free_space(root, right);
+ if (space + push_space * 2 > free_space)
+ break;
+ }
+ }
+
+ if (path->slots[0] == i)
+ push_space += data_size;
+
+ this_item_size = btrfs_item_size(right, item);
+ if (this_item_size + sizeof(*item) + push_space > free_space)
+ break;
+
+ push_items++;
+ push_space += this_item_size + sizeof(*item);
+ }
+
+ if (push_items == 0) {
+ ret = 1;
+ goto out;
+ }
+ if (!empty && push_items == btrfs_header_nritems(right))
+ WARN_ON(1);
+
+ /* push data from right to left */
+ copy_extent_buffer(left, right,
+ btrfs_item_nr_offset(btrfs_header_nritems(left)),
+ btrfs_item_nr_offset(0),
+ push_items * sizeof(struct btrfs_item));
+
+ push_space = BTRFS_LEAF_DATA_SIZE(root) -
+ btrfs_item_offset_nr(right, push_items - 1);
+
+ copy_extent_buffer(left, right, btrfs_leaf_data(left) +
+ leaf_data_end(root, left) - push_space,
+ btrfs_leaf_data(right) +
+ btrfs_item_offset_nr(right, push_items - 1),
+ push_space);
+ old_left_nritems = btrfs_header_nritems(left);
+ BUG_ON(old_left_nritems <= 0);
+
+ old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
+ for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(left, i);
+
+ ioff = btrfs_token_item_offset(left, item, &token);
+ btrfs_set_token_item_offset(left, item,
+ ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size),
+ &token);
+ }
+ btrfs_set_header_nritems(left, old_left_nritems + push_items);
+
+ /* fixup right node */
+ if (push_items > right_nritems) {
+ printk(KERN_CRIT "push items %d nr %u\n", push_items,
+ right_nritems);
+ WARN_ON(1);
+ }
+
+ if (push_items < right_nritems) {
+ push_space = btrfs_item_offset_nr(right, push_items - 1) -
+ leaf_data_end(root, right);
+ memmove_extent_buffer(right, btrfs_leaf_data(right) +
+ BTRFS_LEAF_DATA_SIZE(root) - push_space,
+ btrfs_leaf_data(right) +
+ leaf_data_end(root, right), push_space);
+
+ memmove_extent_buffer(right, btrfs_item_nr_offset(0),
+ btrfs_item_nr_offset(push_items),
+ (btrfs_header_nritems(right) - push_items) *
+ sizeof(struct btrfs_item));
+ }
+ right_nritems -= push_items;
+ btrfs_set_header_nritems(right, right_nritems);
+ push_space = BTRFS_LEAF_DATA_SIZE(root);
+ for (i = 0; i < right_nritems; i++) {
+ item = btrfs_item_nr(right, i);
+
+ push_space = push_space - btrfs_token_item_size(right,
+ item, &token);
+ btrfs_set_token_item_offset(right, item, push_space, &token);
+ }
+
+ btrfs_mark_buffer_dirty(left);
+ if (right_nritems)
+ btrfs_mark_buffer_dirty(right);
+ else
+ clean_tree_block(trans, root, right);
+
+ btrfs_item_key(right, &disk_key, 0);
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+
+ /* then fixup the leaf pointer in the path */
+ if (path->slots[0] < push_items) {
+ path->slots[0] += old_left_nritems;
+ btrfs_tree_unlock(path->nodes[0]);
+ free_extent_buffer(path->nodes[0]);
+ path->nodes[0] = left;
+ path->slots[1] -= 1;
+ } else {
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ path->slots[0] -= push_items;
+ }
+ BUG_ON(path->slots[0] < 0);
+ return ret;
+out:
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ return ret;
+}
+
+/*
+ * push some data in the path leaf to the left, trying to free up at
+ * least data_size bytes. returns zero if the push worked, nonzero otherwise
+ *
+ * max_slot can put a limit on how far into the leaf we'll push items. The
+ * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
+ * items
+ */
+static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_path *path, int min_data_size,
+ int data_size, int empty, u32 max_slot)
+{
+ struct extent_buffer *right = path->nodes[0];
+ struct extent_buffer *left;
+ int slot;
+ int free_space;
+ u32 right_nritems;
+ int ret = 0;
+
+ slot = path->slots[1];
+ if (slot == 0)
+ return 1;
+ if (!path->nodes[1])
+ return 1;
+
+ right_nritems = btrfs_header_nritems(right);
+ if (right_nritems == 0)
+ return 1;
+
+ btrfs_assert_tree_locked(path->nodes[1]);
+
+ left = read_node_slot(root, path->nodes[1], slot - 1);
+ if (left == NULL)
+ return 1;
+
+ btrfs_tree_lock(left);
+ btrfs_set_lock_blocking(left);
+
+ free_space = btrfs_leaf_free_space(root, left);
+ if (free_space < data_size) {
+ ret = 1;
+ goto out;
+ }
+
+ /* cow and double check */
+ ret = btrfs_cow_block(trans, root, left,
+ path->nodes[1], slot - 1, &left);
+ if (ret) {
+ /* we hit -ENOSPC, but it isn't fatal here */
+ if (ret == -ENOSPC)
+ ret = 1;
+ goto out;
+ }
+
+ free_space = btrfs_leaf_free_space(root, left);
+ if (free_space < data_size) {
+ ret = 1;
+ goto out;
+ }
+
+ return __push_leaf_left(trans, root, path, min_data_size,
+ empty, left, free_space, right_nritems,
+ max_slot);
+out:
+ btrfs_tree_unlock(left);
+ free_extent_buffer(left);
+ return ret;
+}
+
+/*
+ * split the path's leaf in two, making sure there is at least data_size
+ * available for the resulting leaf level of the path.
+ */
+static noinline void copy_for_split(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct extent_buffer *l,
+ struct extent_buffer *right,
+ int slot, int mid, int nritems)
+{
+ int data_copy_size;
+ int rt_data_off;
+ int i;
+ struct btrfs_disk_key disk_key;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ nritems = nritems - mid;
+ btrfs_set_header_nritems(right, nritems);
+ data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
+
+ copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
+ btrfs_item_nr_offset(mid),
+ nritems * sizeof(struct btrfs_item));
+
+ copy_extent_buffer(right, l,
+ btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
+ data_copy_size, btrfs_leaf_data(l) +
+ leaf_data_end(root, l), data_copy_size);
+
+ rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
+ btrfs_item_end_nr(l, mid);
+
+ for (i = 0; i < nritems; i++) {
+ struct btrfs_item *item = btrfs_item_nr(right, i);
+ u32 ioff;
+
+ ioff = btrfs_token_item_offset(right, item, &token);
+ btrfs_set_token_item_offset(right, item,
+ ioff + rt_data_off, &token);
+ }
+
+ btrfs_set_header_nritems(l, mid);
+ btrfs_item_key(right, &disk_key, 0);
+ insert_ptr(trans, root, path, &disk_key, right->start,
+ path->slots[1] + 1, 1);
+
+ btrfs_mark_buffer_dirty(right);
+ btrfs_mark_buffer_dirty(l);
+ BUG_ON(path->slots[0] != slot);
+
+ if (mid <= slot) {
+ btrfs_tree_unlock(path->nodes[0]);
+ free_extent_buffer(path->nodes[0]);
+ path->nodes[0] = right;
+ path->slots[0] -= mid;
+ path->slots[1] += 1;
+ } else {
+ btrfs_tree_unlock(right);
+ free_extent_buffer(right);
+ }
+
+ BUG_ON(path->slots[0] < 0);
+}
+
+/*
+ * double splits happen when we need to insert a big item in the middle
+ * of a leaf. A double split can leave us with 3 mostly empty leaves:
+ * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
+ * A B C
+ *
+ * We avoid this by trying to push the items on either side of our target
+ * into the adjacent leaves. If all goes well we can avoid the double split
+ * completely.
+ */
+static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ int data_size)
+{
+ int ret;
+ int progress = 0;
+ int slot;
+ u32 nritems;
+
+ slot = path->slots[0];
+
+ /*
+ * try to push all the items after our slot into the
+ * right leaf
+ */
+ ret = push_leaf_right(trans, root, path, 1, data_size, 0, slot);
+ if (ret < 0)
+ return ret;
+
+ if (ret == 0)
+ progress++;
+
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ /*
+ * our goal is to get our slot at the start or end of a leaf. If
+ * we've done so we're done
+ */
+ if (path->slots[0] == 0 || path->slots[0] == nritems)
+ return 0;
+
+ if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
+ return 0;
+
+ /* try to push all the items before our slot into the next leaf */
+ slot = path->slots[0];
+ ret = push_leaf_left(trans, root, path, 1, data_size, 0, slot);
+ if (ret < 0)
+ return ret;
+
+ if (ret == 0)
+ progress++;
+
+ if (progress)
+ return 0;
+ return 1;
+}
+
+/*
+ * split the path's leaf in two, making sure there is at least data_size
+ * available for the resulting leaf level of the path.
+ *
+ * returns 0 if all went well and < 0 on failure.
+ */
+static noinline int split_leaf(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_key *ins_key,
+ struct btrfs_path *path, int data_size,
+ int extend)
+{
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *l;
+ u32 nritems;
+ int mid;
+ int slot;
+ struct extent_buffer *right;
+ int ret = 0;
+ int wret;
+ int split;
+ int num_doubles = 0;
+ int tried_avoid_double = 0;
+
+ l = path->nodes[0];
+ slot = path->slots[0];
+ if (extend && data_size + btrfs_item_size_nr(l, slot) +
+ sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root))
+ return -EOVERFLOW;
+
+ /* first try to make some room by pushing left and right */
+ if (data_size) {
+ wret = push_leaf_right(trans, root, path, data_size,
+ data_size, 0, 0);
+ if (wret < 0)
+ return wret;
+ if (wret) {
+ wret = push_leaf_left(trans, root, path, data_size,
+ data_size, 0, (u32)-1);
+ if (wret < 0)
+ return wret;
+ }
+ l = path->nodes[0];
+
+ /* did the pushes work? */
+ if (btrfs_leaf_free_space(root, l) >= data_size)
+ return 0;
+ }
+
+ if (!path->nodes[1]) {
+ ret = insert_new_root(trans, root, path, 1);
+ if (ret)
+ return ret;
+ }
+again:
+ split = 1;
+ l = path->nodes[0];
+ slot = path->slots[0];
+ nritems = btrfs_header_nritems(l);
+ mid = (nritems + 1) / 2;
+
+ if (mid <= slot) {
+ if (nritems == 1 ||
+ leaf_space_used(l, mid, nritems - mid) + data_size >
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ if (slot >= nritems) {
+ split = 0;
+ } else {
+ mid = slot;
+ if (mid != nritems &&
+ leaf_space_used(l, mid, nritems - mid) +
+ data_size > BTRFS_LEAF_DATA_SIZE(root)) {
+ if (data_size && !tried_avoid_double)
+ goto push_for_double;
+ split = 2;
+ }
+ }
+ }
+ } else {
+ if (leaf_space_used(l, 0, mid) + data_size >
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ if (!extend && data_size && slot == 0) {
+ split = 0;
+ } else if ((extend || !data_size) && slot == 0) {
+ mid = 1;
+ } else {
+ mid = slot;
+ if (mid != nritems &&
+ leaf_space_used(l, mid, nritems - mid) +
+ data_size > BTRFS_LEAF_DATA_SIZE(root)) {
+ if (data_size && !tried_avoid_double)
+ goto push_for_double;
+ split = 2 ;
+ }
+ }
+ }
+ }
+
+ if (split == 0)
+ btrfs_cpu_key_to_disk(&disk_key, ins_key);
+ else
+ btrfs_item_key(l, &disk_key, mid);
+
+ right = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
+ root->root_key.objectid,
+ &disk_key, 0, l->start, 0, 0);
+ if (IS_ERR(right))
+ return PTR_ERR(right);
+
+ root_add_used(root, root->leafsize);
+
+ memset_extent_buffer(right, 0, 0, sizeof(struct btrfs_header));
+ btrfs_set_header_bytenr(right, right->start);
+ btrfs_set_header_generation(right, trans->transid);
+ btrfs_set_header_backref_rev(right, BTRFS_MIXED_BACKREF_REV);
+ btrfs_set_header_owner(right, root->root_key.objectid);
+ btrfs_set_header_level(right, 0);
+ write_extent_buffer(right, root->fs_info->fsid,
+ (unsigned long)btrfs_header_fsid(right),
+ BTRFS_FSID_SIZE);
+
+ write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
+ (unsigned long)btrfs_header_chunk_tree_uuid(right),
+ BTRFS_UUID_SIZE);
+
+ if (split == 0) {
+ if (mid <= slot) {
+ btrfs_set_header_nritems(right, 0);
+ insert_ptr(trans, root, path, &disk_key, right->start,
+ path->slots[1] + 1, 1);
+ btrfs_tree_unlock(path->nodes[0]);
+ free_extent_buffer(path->nodes[0]);
+ path->nodes[0] = right;
+ path->slots[0] = 0;
+ path->slots[1] += 1;
+ } else {
+ btrfs_set_header_nritems(right, 0);
+ insert_ptr(trans, root, path, &disk_key, right->start,
+ path->slots[1], 1);
+ btrfs_tree_unlock(path->nodes[0]);
+ free_extent_buffer(path->nodes[0]);
+ path->nodes[0] = right;
+ path->slots[0] = 0;
+ if (path->slots[1] == 0)
+ fixup_low_keys(trans, root, path,
+ &disk_key, 1);
+ }
+ btrfs_mark_buffer_dirty(right);
+ return ret;
+ }
+
+ copy_for_split(trans, root, path, l, right, slot, mid, nritems);
+
+ if (split == 2) {
+ BUG_ON(num_doubles != 0);
+ num_doubles++;
+ goto again;
+ }
+
+ return 0;
+
+push_for_double:
+ push_for_double_split(trans, root, path, data_size);
+ tried_avoid_double = 1;
+ if (btrfs_leaf_free_space(root, path->nodes[0]) >= data_size)
+ return 0;
+ goto again;
+}
+
+static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path, int ins_len)
+{
+ struct btrfs_key key;
+ struct extent_buffer *leaf;
+ struct btrfs_file_extent_item *fi;
+ u64 extent_len = 0;
+ u32 item_size;
+ int ret;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+
+ BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
+ key.type != BTRFS_EXTENT_CSUM_KEY);
+
+ if (btrfs_leaf_free_space(root, leaf) >= ins_len)
+ return 0;
+
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ if (key.type == BTRFS_EXTENT_DATA_KEY) {
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ extent_len = btrfs_file_extent_num_bytes(leaf, fi);
+ }
+ btrfs_release_path(path);
+
+ path->keep_locks = 1;
+ path->search_for_split = 1;
+ ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+ path->search_for_split = 0;
+ if (ret < 0)
+ goto err;
+
+ ret = -EAGAIN;
+ leaf = path->nodes[0];
+ /* if our item isn't there or got smaller, return now */
+ if (ret > 0 || item_size != btrfs_item_size_nr(leaf, path->slots[0]))
+ goto err;
+
+ /* the leaf has changed, it now has room. return now */
+ if (btrfs_leaf_free_space(root, path->nodes[0]) >= ins_len)
+ goto err;
+
+ if (key.type == BTRFS_EXTENT_DATA_KEY) {
+ fi = btrfs_item_ptr(leaf, path->slots[0],
+ struct btrfs_file_extent_item);
+ if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
+ goto err;
+ }
+
+ btrfs_set_path_blocking(path);
+ ret = split_leaf(trans, root, &key, path, ins_len, 1);
+ if (ret)
+ goto err;
+
+ path->keep_locks = 0;
+ btrfs_unlock_up_safe(path, 1);
+ return 0;
+err:
+ path->keep_locks = 0;
+ return ret;
+}
+
+static noinline int split_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *new_key,
+ unsigned long split_offset)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ struct btrfs_item *new_item;
+ int slot;
+ char *buf;
+ u32 nritems;
+ u32 item_size;
+ u32 orig_offset;
+ struct btrfs_disk_key disk_key;
+
+ leaf = path->nodes[0];
+ BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
+
+ btrfs_set_path_blocking(path);
+
+ item = btrfs_item_nr(leaf, path->slots[0]);
+ orig_offset = btrfs_item_offset(leaf, item);
+ item_size = btrfs_item_size(leaf, item);
+
+ buf = kmalloc(item_size, GFP_NOFS);
+ if (!buf)
+ return -ENOMEM;
+
+ read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
+ path->slots[0]), item_size);
+
+ slot = path->slots[0] + 1;
+ nritems = btrfs_header_nritems(leaf);
+ if (slot != nritems) {
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+ }
+
+ btrfs_cpu_key_to_disk(&disk_key, new_key);
+ btrfs_set_item_key(leaf, &disk_key, slot);
+
+ new_item = btrfs_item_nr(leaf, slot);
+
+ btrfs_set_item_offset(leaf, new_item, orig_offset);
+ btrfs_set_item_size(leaf, new_item, item_size - split_offset);
+
+ btrfs_set_item_offset(leaf, item,
+ orig_offset + item_size - split_offset);
+ btrfs_set_item_size(leaf, item, split_offset);
+
+ btrfs_set_header_nritems(leaf, nritems + 1);
+
+ /* write the data for the start of the original item */
+ write_extent_buffer(leaf, buf,
+ btrfs_item_ptr_offset(leaf, path->slots[0]),
+ split_offset);
+
+ /* write the data for the new item */
+ write_extent_buffer(leaf, buf + split_offset,
+ btrfs_item_ptr_offset(leaf, slot),
+ item_size - split_offset);
+ btrfs_mark_buffer_dirty(leaf);
+
+ BUG_ON(btrfs_leaf_free_space(root, leaf) < 0);
+ kfree(buf);
+ return 0;
+}
+
+/*
+ * This function splits a single item into two items,
+ * giving 'new_key' to the new item and splitting the
+ * old one at split_offset (from the start of the item).
+ *
+ * The path may be released by this operation. After
+ * the split, the path is pointing to the old item. The
+ * new item is going to be in the same node as the old one.
+ *
+ * Note, the item being split must be smaller enough to live alone on
+ * a tree block with room for one extra struct btrfs_item
+ *
+ * This allows us to split the item in place, keeping a lock on the
+ * leaf the entire time.
+ */
+int btrfs_split_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *new_key,
+ unsigned long split_offset)
+{
+ int ret;
+ ret = setup_leaf_for_split(trans, root, path,
+ sizeof(struct btrfs_item));
+ if (ret)
+ return ret;
+
+ ret = split_item(trans, root, path, new_key, split_offset);
+ return ret;
+}
+
+/*
+ * This function duplicate a item, giving 'new_key' to the new item.
+ * It guarantees both items live in the same tree leaf and the new item
+ * is contiguous with the original item.
+ *
+ * This allows us to split file extent in place, keeping a lock on the
+ * leaf the entire time.
+ */
+int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *new_key)
+{
+ struct extent_buffer *leaf;
+ int ret;
+ u32 item_size;
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ ret = setup_leaf_for_split(trans, root, path,
+ item_size + sizeof(struct btrfs_item));
+ if (ret)
+ return ret;
+
+ path->slots[0]++;
+ setup_items_for_insert(trans, root, path, new_key, &item_size,
+ item_size, item_size +
+ sizeof(struct btrfs_item), 1);
+ leaf = path->nodes[0];
+ memcpy_extent_buffer(leaf,
+ btrfs_item_ptr_offset(leaf, path->slots[0]),
+ btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
+ item_size);
+ return 0;
+}
+
+/*
+ * make the item pointed to by the path smaller. new_size indicates
+ * how small to make it, and from_end tells us if we just chop bytes
+ * off the end of the item or if we shift the item to chop bytes off
+ * the front.
+ */
+void btrfs_truncate_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ u32 new_size, int from_end)
+{
+ int slot;
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ u32 nritems;
+ unsigned int data_end;
+ unsigned int old_data_start;
+ unsigned int old_size;
+ unsigned int size_diff;
+ int i;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+
+ old_size = btrfs_item_size_nr(leaf, slot);
+ if (old_size == new_size)
+ return;
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ old_data_start = btrfs_item_offset_nr(leaf, slot);
+
+ size_diff = old_size - new_size;
+
+ BUG_ON(slot < 0);
+ BUG_ON(slot >= nritems);
+
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+ item = btrfs_item_nr(leaf, i);
+
+ ioff = btrfs_token_item_offset(leaf, item, &token);
+ btrfs_set_token_item_offset(leaf, item,
+ ioff + size_diff, &token);
+ }
+
+ /* shift the data */
+ if (from_end) {
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + size_diff, btrfs_leaf_data(leaf) +
+ data_end, old_data_start + new_size - data_end);
+ } else {
+ struct btrfs_disk_key disk_key;
+ u64 offset;
+
+ btrfs_item_key(leaf, &disk_key, slot);
+
+ if (btrfs_disk_key_type(&disk_key) == BTRFS_EXTENT_DATA_KEY) {
+ unsigned long ptr;
+ struct btrfs_file_extent_item *fi;
+
+ fi = btrfs_item_ptr(leaf, slot,
+ struct btrfs_file_extent_item);
+ fi = (struct btrfs_file_extent_item *)(
+ (unsigned long)fi - size_diff);
+
+ if (btrfs_file_extent_type(leaf, fi) ==
+ BTRFS_FILE_EXTENT_INLINE) {
+ ptr = btrfs_item_ptr_offset(leaf, slot);
+ memmove_extent_buffer(leaf, ptr,
+ (unsigned long)fi,
+ offsetof(struct btrfs_file_extent_item,
+ disk_bytenr));
+ }
+ }
+
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + size_diff, btrfs_leaf_data(leaf) +
+ data_end, old_data_start - data_end);
+
+ offset = btrfs_disk_key_offset(&disk_key);
+ btrfs_set_disk_key_offset(&disk_key, offset + size_diff);
+ btrfs_set_item_key(leaf, &disk_key, slot);
+ if (slot == 0)
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_set_item_size(leaf, item, new_size);
+ btrfs_mark_buffer_dirty(leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+}
+
+/*
+ * make the item pointed to by the path bigger, data_size is the new size.
+ */
+void btrfs_extend_item(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ u32 data_size)
+{
+ int slot;
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ u32 nritems;
+ unsigned int data_end;
+ unsigned int old_data;
+ unsigned int old_size;
+ int i;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < data_size) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+ slot = path->slots[0];
+ old_data = btrfs_item_end_nr(leaf, slot);
+
+ BUG_ON(slot < 0);
+ if (slot >= nritems) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d too large, nritems %d\n",
+ slot, nritems);
+ BUG_ON(1);
+ }
+
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+ item = btrfs_item_nr(leaf, i);
+
+ ioff = btrfs_token_item_offset(leaf, item, &token);
+ btrfs_set_token_item_offset(leaf, item,
+ ioff - data_size, &token);
+ }
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - data_size, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+
+ data_end = old_data;
+ old_size = btrfs_item_size_nr(leaf, slot);
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_set_item_size(leaf, item, old_size + data_size);
+ btrfs_mark_buffer_dirty(leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+}
+
+/*
+ * Given a key and some data, insert items into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ * Returns the number of keys that were inserted.
+ */
+int btrfs_insert_some_items(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *cpu_key, u32 *data_size,
+ int nr)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ int ret = 0;
+ int slot;
+ int i;
+ u32 nritems;
+ u32 total_data = 0;
+ u32 total_size = 0;
+ unsigned int data_end;
+ struct btrfs_disk_key disk_key;
+ struct btrfs_key found_key;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ for (i = 0; i < nr; i++) {
+ if (total_size + data_size[i] + sizeof(struct btrfs_item) >
+ BTRFS_LEAF_DATA_SIZE(root)) {
+ break;
+ nr = i;
+ }
+ total_data += data_size[i];
+ total_size += data_size[i] + sizeof(struct btrfs_item);
+ }
+ BUG_ON(nr == 0);
+
+ ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
+ if (ret == 0)
+ return -EEXIST;
+ if (ret < 0)
+ goto out;
+
+ leaf = path->nodes[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < total_size) {
+ for (i = nr; i >= 0; i--) {
+ total_data -= data_size[i];
+ total_size -= data_size[i] + sizeof(struct btrfs_item);
+ if (total_size < btrfs_leaf_free_space(root, leaf))
+ break;
+ }
+ nr = i;
+ }
+
+ slot = path->slots[0];
+ BUG_ON(slot < 0);
+
+ if (slot != nritems) {
+ unsigned int old_data = btrfs_item_end_nr(leaf, slot);
+
+ item = btrfs_item_nr(leaf, slot);
+ btrfs_item_key_to_cpu(leaf, &found_key, slot);
+
+ /* figure out how many keys we can insert in here */
+ total_data = data_size[0];
+ for (i = 1; i < nr; i++) {
+ if (btrfs_comp_cpu_keys(&found_key, cpu_key + i) <= 0)
+ break;
+ total_data += data_size[i];
+ }
+ nr = i;
+
+ if (old_data < data_end) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
+ slot, old_data, data_end);
+ BUG_ON(1);
+ }
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ ioff = btrfs_token_item_offset(leaf, item, &token);
+ btrfs_set_token_item_offset(leaf, item,
+ ioff - total_data, &token);
+ }
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - total_data, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+ data_end = old_data;
+ } else {
+ /*
+ * this sucks but it has to be done, if we are inserting at
+ * the end of the leaf only insert 1 of the items, since we
+ * have no way of knowing whats on the next leaf and we'd have
+ * to drop our current locks to figure it out
+ */
+ nr = 1;
+ }
+
+ /* setup the item for the new data */
+ for (i = 0; i < nr; i++) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
+ btrfs_set_item_key(leaf, &disk_key, slot + i);
+ item = btrfs_item_nr(leaf, slot + i);
+ btrfs_set_token_item_offset(leaf, item,
+ data_end - data_size[i], &token);
+ data_end -= data_size[i];
+ btrfs_set_token_item_size(leaf, item, data_size[i], &token);
+ }
+ btrfs_set_header_nritems(leaf, nritems + nr);
+ btrfs_mark_buffer_dirty(leaf);
+
+ ret = 0;
+ if (slot == 0) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+out:
+ if (!ret)
+ ret = nr;
+ return ret;
+}
+
+/*
+ * this is a helper for btrfs_insert_empty_items, the main goal here is
+ * to save stack depth by doing the bulk of the work in a function
+ * that doesn't call btrfs_search_slot
+ */
+void setup_items_for_insert(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *cpu_key, u32 *data_size,
+ u32 total_data, u32 total_size, int nr)
+{
+ struct btrfs_item *item;
+ int i;
+ u32 nritems;
+ unsigned int data_end;
+ struct btrfs_disk_key disk_key;
+ struct extent_buffer *leaf;
+ int slot;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ leaf = path->nodes[0];
+ slot = path->slots[0];
+
+ nritems = btrfs_header_nritems(leaf);
+ data_end = leaf_data_end(root, leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < total_size) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "not enough freespace need %u have %d\n",
+ total_size, btrfs_leaf_free_space(root, leaf));
+ BUG();
+ }
+
+ if (slot != nritems) {
+ unsigned int old_data = btrfs_item_end_nr(leaf, slot);
+
+ if (old_data < data_end) {
+ btrfs_print_leaf(root, leaf);
+ printk(KERN_CRIT "slot %d old_data %d data_end %d\n",
+ slot, old_data, data_end);
+ BUG_ON(1);
+ }
+ /*
+ * item0..itemN ... dataN.offset..dataN.size .. data0.size
+ */
+ /* first correct the data pointers */
+ for (i = slot; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ ioff = btrfs_token_item_offset(leaf, item, &token);
+ btrfs_set_token_item_offset(leaf, item,
+ ioff - total_data, &token);
+ }
+ /* shift the items */
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
+ btrfs_item_nr_offset(slot),
+ (nritems - slot) * sizeof(struct btrfs_item));
+
+ /* shift the data */
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end - total_data, btrfs_leaf_data(leaf) +
+ data_end, old_data - data_end);
+ data_end = old_data;
+ }
+
+ /* setup the item for the new data */
+ for (i = 0; i < nr; i++) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
+ btrfs_set_item_key(leaf, &disk_key, slot + i);
+ item = btrfs_item_nr(leaf, slot + i);
+ btrfs_set_token_item_offset(leaf, item,
+ data_end - data_size[i], &token);
+ data_end -= data_size[i];
+ btrfs_set_token_item_size(leaf, item, data_size[i], &token);
+ }
+
+ btrfs_set_header_nritems(leaf, nritems + nr);
+
+ if (slot == 0) {
+ btrfs_cpu_key_to_disk(&disk_key, cpu_key);
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+ btrfs_unlock_up_safe(path, 1);
+ btrfs_mark_buffer_dirty(leaf);
+
+ if (btrfs_leaf_free_space(root, leaf) < 0) {
+ btrfs_print_leaf(root, leaf);
+ BUG();
+ }
+}
+
+/*
+ * Given a key and some data, insert items into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
+int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct btrfs_key *cpu_key, u32 *data_size,
+ int nr)
+{
+ int ret = 0;
+ int slot;
+ int i;
+ u32 total_size = 0;
+ u32 total_data = 0;
+
+ for (i = 0; i < nr; i++)
+ total_data += data_size[i];
+
+ total_size = total_data + (nr * sizeof(struct btrfs_item));
+ ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
+ if (ret == 0)
+ return -EEXIST;
+ if (ret < 0)
+ return ret;
+
+ slot = path->slots[0];
+ BUG_ON(slot < 0);
+
+ setup_items_for_insert(trans, root, path, cpu_key, data_size,
+ total_data, total_size, nr);
+ return 0;
+}
+
+/*
+ * Given a key and some data, insert an item into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
+int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
+ *root, struct btrfs_key *cpu_key, void *data, u32
+ data_size)
+{
+ int ret = 0;
+ struct btrfs_path *path;
+ struct extent_buffer *leaf;
+ unsigned long ptr;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size);
+ if (!ret) {
+ leaf = path->nodes[0];
+ ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ write_extent_buffer(leaf, data, ptr, data_size);
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ btrfs_free_path(path);
+ return ret;
+}
+
+/*
+ * delete the pointer from a given node.
+ *
+ * the tree should have been previously balanced so the deletion does not
+ * empty a node.
+ */
+static void del_ptr(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_path *path, int level, int slot)
+{
+ struct extent_buffer *parent = path->nodes[level];
+ u32 nritems;
+
+ nritems = btrfs_header_nritems(parent);
+ if (slot != nritems - 1) {
+ memmove_extent_buffer(parent,
+ btrfs_node_key_ptr_offset(slot),
+ btrfs_node_key_ptr_offset(slot + 1),
+ sizeof(struct btrfs_key_ptr) *
+ (nritems - slot - 1));
+ }
+ nritems--;
+ btrfs_set_header_nritems(parent, nritems);
+ if (nritems == 0 && parent == root->node) {
+ BUG_ON(btrfs_header_level(root->node) != 1);
+ /* just turn the root into a leaf and break */
+ btrfs_set_header_level(root->node, 0);
+ } else if (slot == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_node_key(parent, &disk_key, 0);
+ fixup_low_keys(trans, root, path, &disk_key, level + 1);
+ }
+ btrfs_mark_buffer_dirty(parent);
+}
+
+/*
+ * a helper function to delete the leaf pointed to by path->slots[1] and
+ * path->nodes[1].
+ *
+ * This deletes the pointer in path->nodes[1] and frees the leaf
+ * block extent. zero is returned if it all worked out, < 0 otherwise.
+ *
+ * The path must have already been setup for deleting the leaf, including
+ * all the proper balancing. path->nodes[1] must be locked.
+ */
+static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct extent_buffer *leaf)
+{
+ WARN_ON(btrfs_header_generation(leaf) != trans->transid);
+ del_ptr(trans, root, path, 1, path->slots[1]);
+
+ /*
+ * btrfs_free_extent is expensive, we want to make sure we
+ * aren't holding any locks when we call it
+ */
+ btrfs_unlock_up_safe(path, 0);
+
+ root_sub_used(root, leaf->len);
+
+ extent_buffer_get(leaf);
+ btrfs_free_tree_block(trans, root, leaf, 0, 1, 0);
+ free_extent_buffer_stale(leaf);
+}
+/*
+ * delete the item at the leaf level in path. If that empties
+ * the leaf, remove it from the tree
+ */
+int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
+ struct btrfs_path *path, int slot, int nr)
+{
+ struct extent_buffer *leaf;
+ struct btrfs_item *item;
+ int last_off;
+ int dsize = 0;
+ int ret = 0;
+ int wret;
+ int i;
+ u32 nritems;
+ struct btrfs_map_token token;
+
+ btrfs_init_map_token(&token);
+
+ leaf = path->nodes[0];
+ last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
+
+ for (i = 0; i < nr; i++)
+ dsize += btrfs_item_size_nr(leaf, slot + i);
+
+ nritems = btrfs_header_nritems(leaf);
+
+ if (slot + nr != nritems) {
+ int data_end = leaf_data_end(root, leaf);
+
+ memmove_extent_buffer(leaf, btrfs_leaf_data(leaf) +
+ data_end + dsize,
+ btrfs_leaf_data(leaf) + data_end,
+ last_off - data_end);
+
+ for (i = slot + nr; i < nritems; i++) {
+ u32 ioff;
+
+ item = btrfs_item_nr(leaf, i);
+ ioff = btrfs_token_item_offset(leaf, item, &token);
+ btrfs_set_token_item_offset(leaf, item,
+ ioff + dsize, &token);
+ }
+
+ memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
+ btrfs_item_nr_offset(slot + nr),
+ sizeof(struct btrfs_item) *
+ (nritems - slot - nr));
+ }
+ btrfs_set_header_nritems(leaf, nritems - nr);
+ nritems -= nr;
+
+ /* delete the leaf if we've emptied it */
+ if (nritems == 0) {
+ if (leaf == root->node) {
+ btrfs_set_header_level(leaf, 0);
+ } else {
+ btrfs_set_path_blocking(path);
+ clean_tree_block(trans, root, leaf);
+ btrfs_del_leaf(trans, root, path, leaf);
+ }
+ } else {
+ int used = leaf_space_used(leaf, 0, nritems);
+ if (slot == 0) {
+ struct btrfs_disk_key disk_key;
+
+ btrfs_item_key(leaf, &disk_key, 0);
+ fixup_low_keys(trans, root, path, &disk_key, 1);
+ }
+
+ /* delete the leaf if it is mostly empty */
+ if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
+ /* push_leaf_left fixes the path.
+ * make sure the path still points to our leaf
+ * for possible call to del_ptr below
+ */
+ slot = path->slots[1];
+ extent_buffer_get(leaf);
+
+ btrfs_set_path_blocking(path);
+ wret = push_leaf_left(trans, root, path, 1, 1,
+ 1, (u32)-1);
+ if (wret < 0 && wret != -ENOSPC)
+ ret = wret;
+
+ if (path->nodes[0] == leaf &&
+ btrfs_header_nritems(leaf)) {
+ wret = push_leaf_right(trans, root, path, 1,
+ 1, 1, 0);
+ if (wret < 0 && wret != -ENOSPC)
+ ret = wret;
+ }
+
+ if (btrfs_header_nritems(leaf) == 0) {
+ path->slots[1] = slot;
+ btrfs_del_leaf(trans, root, path, leaf);
+ free_extent_buffer(leaf);
+ ret = 0;
+ } else {
+ /* if we're still in the path, make sure
+ * we're dirty. Otherwise, one of the
+ * push_leaf functions must have already
+ * dirtied this buffer
+ */
+ if (path->nodes[0] == leaf)
+ btrfs_mark_buffer_dirty(leaf);
+ free_extent_buffer(leaf);
+ }
+ } else {
+ btrfs_mark_buffer_dirty(leaf);
+ }
+ }
+ return ret;
+}
+
+/*
+ * search the tree again to find a leaf with lesser keys
+ * returns 0 if it found something or 1 if there are no lesser leaves.
+ * returns < 0 on io errors.
+ *
+ * This may release the path, and so you may lose any locks held at the
+ * time you call it.
+ */
+int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ struct btrfs_key key;
+ struct btrfs_disk_key found_key;
+ int ret;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
+
+ if (key.offset > 0)
+ key.offset--;
+ else if (key.type > 0)
+ key.type--;
+ else if (key.objectid > 0)
+ key.objectid--;
+ else
+ return 1;
+
+ btrfs_release_path(path);
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ return ret;
+ btrfs_item_key(path->nodes[0], &found_key, 0);
+ ret = comp_keys(&found_key, &key);
+ if (ret < 0)
+ return 0;
+ return 1;
+}
+
+/*
+ * A helper function to walk down the tree starting at min_key, and looking
+ * for nodes or leaves that are either in cache or have a minimum
+ * transaction id. This is used by the btree defrag code, and tree logging
+ *
+ * This does not cow, but it does stuff the starting key it finds back
+ * into min_key, so you can call btrfs_search_slot with cow=1 on the
+ * key and get a writable path.
+ *
+ * This does lock as it descends, and path->keep_locks should be set
+ * to 1 by the caller.
+ *
+ * This honors path->lowest_level to prevent descent past a given level
+ * of the tree.
+ *
+ * min_trans indicates the oldest transaction that you are interested
+ * in walking through. Any nodes or leaves older than min_trans are
+ * skipped over (without reading them).
+ *
+ * returns zero if something useful was found, < 0 on error and 1 if there
+ * was nothing in the tree that matched the search criteria.
+ */
+int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
+ struct btrfs_key *max_key,
+ struct btrfs_path *path, int cache_only,
+ u64 min_trans)
+{
+ struct extent_buffer *cur;
+ struct btrfs_key found_key;
+ int slot;
+ int sret;
+ u32 nritems;
+ int level;
+ int ret = 1;
+
+ WARN_ON(!path->keep_locks);
+again:
+ cur = btrfs_read_lock_root_node(root);
+ level = btrfs_header_level(cur);
+ WARN_ON(path->nodes[level]);
+ path->nodes[level] = cur;
+ path->locks[level] = BTRFS_READ_LOCK;
+
+ if (btrfs_header_generation(cur) < min_trans) {
+ ret = 1;
+ goto out;
+ }
+ while (1) {
+ nritems = btrfs_header_nritems(cur);
+ level = btrfs_header_level(cur);
+ sret = bin_search(cur, min_key, level, &slot);
+
+ /* at the lowest level, we're done, setup the path and exit */
+ if (level == path->lowest_level) {
+ if (slot >= nritems)
+ goto find_next_key;
+ ret = 0;
+ path->slots[level] = slot;
+ btrfs_item_key_to_cpu(cur, &found_key, slot);
+ goto out;
+ }
+ if (sret && slot > 0)
+ slot--;
+ /*
+ * check this node pointer against the cache_only and
+ * min_trans parameters. If it isn't in cache or is too
+ * old, skip to the next one.
+ */
+ while (slot < nritems) {
+ u64 blockptr;
+ u64 gen;
+ struct extent_buffer *tmp;
+ struct btrfs_disk_key disk_key;
+
+ blockptr = btrfs_node_blockptr(cur, slot);
+ gen = btrfs_node_ptr_generation(cur, slot);
+ if (gen < min_trans) {
+ slot++;
+ continue;
+ }
+ if (!cache_only)
+ break;
+
+ if (max_key) {
+ btrfs_node_key(cur, &disk_key, slot);
+ if (comp_keys(&disk_key, max_key) >= 0) {
+ ret = 1;
+ goto out;
+ }
+ }
+
+ tmp = btrfs_find_tree_block(root, blockptr,
+ btrfs_level_size(root, level - 1));
+
+ if (tmp && btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
+ free_extent_buffer(tmp);
+ break;
+ }
+ if (tmp)
+ free_extent_buffer(tmp);
+ slot++;
+ }
+find_next_key:
+ /*
+ * we didn't find a candidate key in this node, walk forward
+ * and find another one
+ */
+ if (slot >= nritems) {
+ path->slots[level] = slot;
+ btrfs_set_path_blocking(path);
+ sret = btrfs_find_next_key(root, path, min_key, level,
+ cache_only, min_trans);
+ if (sret == 0) {
+ btrfs_release_path(path);
+ goto again;
+ } else {
+ goto out;
+ }
+ }
+ /* save our key for returning back */
+ btrfs_node_key_to_cpu(cur, &found_key, slot);
+ path->slots[level] = slot;
+ if (level == path->lowest_level) {
+ ret = 0;
+ unlock_up(path, level, 1, 0, NULL);
+ goto out;
+ }
+ btrfs_set_path_blocking(path);
+ cur = read_node_slot(root, cur, slot);
+ BUG_ON(!cur); /* -ENOMEM */
+
+ btrfs_tree_read_lock(cur);
+
+ path->locks[level - 1] = BTRFS_READ_LOCK;
+ path->nodes[level - 1] = cur;
+ unlock_up(path, level, 1, 0, NULL);
+ btrfs_clear_path_blocking(path, NULL, 0);
+ }
+out:
+ if (ret == 0)
+ memcpy(min_key, &found_key, sizeof(found_key));
+ btrfs_set_path_blocking(path);
+ return ret;
+}
+
+/*
+ * this is similar to btrfs_next_leaf, but does not try to preserve
+ * and fixup the path. It looks for and returns the next key in the
+ * tree based on the current path and the cache_only and min_trans
+ * parameters.
+ *
+ * 0 is returned if another key is found, < 0 if there are any errors
+ * and 1 is returned if there are no higher keys in the tree
+ *
+ * path->keep_locks should be set to 1 on the search made before
+ * calling this function.
+ */
+int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
+ struct btrfs_key *key, int level,
+ int cache_only, u64 min_trans)
+{
+ int slot;
+ struct extent_buffer *c;
+
+ WARN_ON(!path->keep_locks);
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level])
+ return 1;
+
+ slot = path->slots[level] + 1;
+ c = path->nodes[level];
+next:
+ if (slot >= btrfs_header_nritems(c)) {
+ int ret;
+ int orig_lowest;
+ struct btrfs_key cur_key;
+ if (level + 1 >= BTRFS_MAX_LEVEL ||
+ !path->nodes[level + 1])
+ return 1;
+
+ if (path->locks[level + 1]) {
+ level++;
+ continue;
+ }
+
+ slot = btrfs_header_nritems(c) - 1;
+ if (level == 0)
+ btrfs_item_key_to_cpu(c, &cur_key, slot);
+ else
+ btrfs_node_key_to_cpu(c, &cur_key, slot);
+
+ orig_lowest = path->lowest_level;
+ btrfs_release_path(path);
+ path->lowest_level = level;
+ ret = btrfs_search_slot(NULL, root, &cur_key, path,
+ 0, 0);
+ path->lowest_level = orig_lowest;
+ if (ret < 0)
+ return ret;
+
+ c = path->nodes[level];
+ slot = path->slots[level];
+ if (ret == 0)
+ slot++;
+ goto next;
+ }
+
+ if (level == 0)
+ btrfs_item_key_to_cpu(c, key, slot);
+ else {
+ u64 blockptr = btrfs_node_blockptr(c, slot);
+ u64 gen = btrfs_node_ptr_generation(c, slot);
+
+ if (cache_only) {
+ struct extent_buffer *cur;
+ cur = btrfs_find_tree_block(root, blockptr,
+ btrfs_level_size(root, level - 1));
+ if (!cur ||
+ btrfs_buffer_uptodate(cur, gen, 1) <= 0) {
+ slot++;
+ if (cur)
+ free_extent_buffer(cur);
+ goto next;
+ }
+ free_extent_buffer(cur);
+ }
+ if (gen < min_trans) {
+ slot++;
+ goto next;
+ }
+ btrfs_node_key_to_cpu(c, key, slot);
+ }
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * search the tree again to find a leaf with greater keys
+ * returns 0 if it found something or 1 if there are no greater leaves.
+ * returns < 0 on io errors.
+ */
+int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
+{
+ int slot;
+ int level;
+ struct extent_buffer *c;
+ struct extent_buffer *next;
+ struct btrfs_key key;
+ u32 nritems;
+ int ret;
+ int old_spinning = path->leave_spinning;
+ int next_rw_lock = 0;
+
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ if (nritems == 0)
+ return 1;
+
+ btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
+again:
+ level = 1;
+ next = NULL;
+ next_rw_lock = 0;
+ btrfs_release_path(path);
+
+ path->keep_locks = 1;
+ path->leave_spinning = 1;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ path->keep_locks = 0;
+
+ if (ret < 0)
+ return ret;
+
+ nritems = btrfs_header_nritems(path->nodes[0]);
+ /*
+ * by releasing the path above we dropped all our locks. A balance
+ * could have added more items next to the key that used to be
+ * at the very end of the block. So, check again here and
+ * advance the path if there are now more items available.
+ */
+ if (nritems > 0 && path->slots[0] < nritems - 1) {
+ if (ret == 0)
+ path->slots[0]++;
+ ret = 0;
+ goto done;
+ }
+
+ while (level < BTRFS_MAX_LEVEL) {
+ if (!path->nodes[level]) {
+ ret = 1;
+ goto done;
+ }
+
+ slot = path->slots[level] + 1;
+ c = path->nodes[level];
+ if (slot >= btrfs_header_nritems(c)) {
+ level++;
+ if (level == BTRFS_MAX_LEVEL) {
+ ret = 1;
+ goto done;
+ }
+ continue;
+ }
+
+ if (next) {
+ btrfs_tree_unlock_rw(next, next_rw_lock);
+ free_extent_buffer(next);
+ }
+
+ next = c;
+ next_rw_lock = path->locks[level];
+ ret = read_block_for_search(NULL, root, path, &next, level,
+ slot, &key);
+ if (ret == -EAGAIN)
+ goto again;
+
+ if (ret < 0) {
+ btrfs_release_path(path);
+ goto done;
+ }
+
+ if (!path->skip_locking) {
+ ret = btrfs_try_tree_read_lock(next);
+ if (!ret) {
+ btrfs_set_path_blocking(path);
+ btrfs_tree_read_lock(next);
+ btrfs_clear_path_blocking(path, next,
+ BTRFS_READ_LOCK);
+ }
+ next_rw_lock = BTRFS_READ_LOCK;
+ }
+ break;
+ }
+ path->slots[level] = slot;
+ while (1) {
+ level--;
+ c = path->nodes[level];
+ if (path->locks[level])
+ btrfs_tree_unlock_rw(c, path->locks[level]);
+
+ free_extent_buffer(c);
+ path->nodes[level] = next;
+ path->slots[level] = 0;
+ if (!path->skip_locking)
+ path->locks[level] = next_rw_lock;
+ if (!level)
+ break;
+
+ ret = read_block_for_search(NULL, root, path, &next, level,
+ 0, &key);
+ if (ret == -EAGAIN)
+ goto again;
+
+ if (ret < 0) {
+ btrfs_release_path(path);
+ goto done;
+ }
+
+ if (!path->skip_locking) {
+ ret = btrfs_try_tree_read_lock(next);
+ if (!ret) {
+ btrfs_set_path_blocking(path);
+ btrfs_tree_read_lock(next);
+ btrfs_clear_path_blocking(path, next,
+ BTRFS_READ_LOCK);
+ }
+ next_rw_lock = BTRFS_READ_LOCK;
+ }
+ }
+ ret = 0;
+done:
+ unlock_up(path, 0, 1, 0, NULL);
+ path->leave_spinning = old_spinning;
+ if (!old_spinning)
+ btrfs_set_path_blocking(path);
+
+ return ret;
+}
+
+/*
+ * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
+ * searching until it gets past min_objectid or finds an item of 'type'
+ *
+ * returns 0 if something is found, 1 if nothing was found and < 0 on error
+ */
+int btrfs_previous_item(struct btrfs_root *root,
+ struct btrfs_path *path, u64 min_objectid,
+ int type)
+{
+ struct btrfs_key found_key;
+ struct extent_buffer *leaf;
+ u32 nritems;
+ int ret;
+
+ while (1) {
+ if (path->slots[0] == 0) {
+ btrfs_set_path_blocking(path);
+ ret = btrfs_prev_leaf(root, path);
+ if (ret != 0)
+ return ret;
+ } else {
+ path->slots[0]--;
+ }
+ leaf = path->nodes[0];
+ nritems = btrfs_header_nritems(leaf);
+ if (nritems == 0)
+ return 1;
+ if (path->slots[0] == nritems)
+ path->slots[0]--;
+
+ btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+ if (found_key.objectid < min_objectid)
+ break;
+ if (found_key.type == type)
+ return 0;
+ if (found_key.objectid == min_objectid &&
+ found_key.type < type)
+ break;
+ }
+ return 1;
+}