| /* |
| * 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 "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 int 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); |
| if (path) |
| path->reada = 1; |
| 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]) |
| btrfs_set_lock_blocking(p->nodes[i]); |
| } |
| } |
| |
| /* |
| * 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 i; |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| /* 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(held); |
| 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(p->nodes[i]); |
| } |
| |
| #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| if (held) |
| btrfs_clear_lock_blocking(held); |
| #endif |
| } |
| |
| /* this also releases the path */ |
| void btrfs_free_path(struct btrfs_path *p) |
| { |
| btrfs_release_path(NULL, 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_root *root, 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(p->nodes[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; |
| spin_lock(&root->node_lock); |
| eb = root->node; |
| extent_buffer_get(eb); |
| spin_unlock(&root->node_lock); |
| 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); |
| |
| spin_lock(&root->node_lock); |
| if (eb == root->node) { |
| spin_unlock(&root->node_lock); |
| break; |
| } |
| spin_unlock(&root->node_lock); |
| |
| btrfs_tree_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) |
| { |
| if (root->track_dirty && list_empty(&root->dirty_list)) { |
| list_add(&root->dirty_list, |
| &root->fs_info->dirty_cowonly_roots); |
| } |
| } |
| |
| /* |
| * 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; |
| u32 nritems; |
| 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); |
| nritems = btrfs_header_nritems(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); |
| 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); |
| else |
| ret = btrfs_inc_ref(trans, root, cow, 0); |
| |
| 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) |
| { |
| 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); |
| BUG_ON(ret); |
| BUG_ON(refs == 0); |
| } 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); |
| BUG_ON(ret); |
| |
| if (root->root_key.objectid == |
| BTRFS_TREE_RELOC_OBJECTID) { |
| ret = btrfs_dec_ref(trans, root, buf, 0); |
| BUG_ON(ret); |
| ret = btrfs_inc_ref(trans, root, cow, 1); |
| BUG_ON(ret); |
| } |
| 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); |
| else |
| ret = btrfs_inc_ref(trans, root, cow, 0); |
| BUG_ON(ret); |
| } |
| if (new_flags != 0) { |
| ret = btrfs_set_disk_extent_flags(trans, root, |
| buf->start, |
| buf->len, |
| new_flags, 0); |
| BUG_ON(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); |
| else |
| ret = btrfs_inc_ref(trans, root, cow, 0); |
| BUG_ON(ret); |
| ret = btrfs_dec_ref(trans, root, buf, 1); |
| BUG_ON(ret); |
| } |
| clean_tree_block(trans, root, buf); |
| } |
| 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; |
| 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); |
| 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); |
| |
| update_ref_for_cow(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; |
| |
| spin_lock(&root->node_lock); |
| root->node = cow; |
| extent_buffer_get(cow); |
| spin_unlock(&root->node_lock); |
| |
| btrfs_free_extent(trans, root, buf->start, buf->len, |
| parent_start, root->root_key.objectid, |
| level, 0); |
| 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_extent(trans, root, buf->start, buf->len, |
| parent_start, root->root_key.objectid, |
| level, 0); |
| } |
| if (unlock_orig) |
| btrfs_tree_unlock(buf); |
| free_extent_buffer(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) |
| { |
| 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))) |
| 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); |
| 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; |
| |
| if (!parent->map_token) { |
| map_extent_buffer(parent, |
| btrfs_node_key_ptr_offset(i), |
| sizeof(struct btrfs_key_ptr), |
| &parent->map_token, &parent->kaddr, |
| &parent->map_start, &parent->map_len, |
| KM_USER1); |
| } |
| 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; |
| } |
| if (parent->map_token) { |
| unmap_extent_buffer(parent, parent->map_token, |
| KM_USER1); |
| parent->map_token = NULL; |
| } |
| |
| cur = btrfs_find_tree_block(root, blocknr, blocksize); |
| if (cur) |
| uptodate = btrfs_buffer_uptodate(cur, gen); |
| else |
| uptodate = 0; |
| if (!cur || !uptodate) { |
| if (cache_only) { |
| free_extent_buffer(cur); |
| continue; |
| } |
| if (!cur) { |
| cur = read_tree_block(root, blocknr, |
| blocksize, gen); |
| } 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); |
| } |
| if (parent->map_token) { |
| unmap_extent_buffer(parent, parent->map_token, |
| KM_USER1); |
| parent->map_token = NULL; |
| } |
| 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); |
| } |
| |
| /* |
| * extra debugging checks to make sure all the items in a key are |
| * well formed and in the proper order |
| */ |
| static int check_node(struct btrfs_root *root, struct btrfs_path *path, |
| int level) |
| { |
| struct extent_buffer *parent = NULL; |
| struct extent_buffer *node = path->nodes[level]; |
| struct btrfs_disk_key parent_key; |
| struct btrfs_disk_key node_key; |
| int parent_slot; |
| int slot; |
| struct btrfs_key cpukey; |
| u32 nritems = btrfs_header_nritems(node); |
| |
| if (path->nodes[level + 1]) |
| parent = path->nodes[level + 1]; |
| |
| slot = path->slots[level]; |
| BUG_ON(nritems == 0); |
| if (parent) { |
| parent_slot = path->slots[level + 1]; |
| btrfs_node_key(parent, &parent_key, parent_slot); |
| btrfs_node_key(node, &node_key, 0); |
| BUG_ON(memcmp(&parent_key, &node_key, |
| sizeof(struct btrfs_disk_key))); |
| BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
| btrfs_header_bytenr(node)); |
| } |
| BUG_ON(nritems > BTRFS_NODEPTRS_PER_BLOCK(root)); |
| if (slot != 0) { |
| btrfs_node_key_to_cpu(node, &cpukey, slot - 1); |
| btrfs_node_key(node, &node_key, slot); |
| BUG_ON(comp_keys(&node_key, &cpukey) <= 0); |
| } |
| if (slot < nritems - 1) { |
| btrfs_node_key_to_cpu(node, &cpukey, slot + 1); |
| btrfs_node_key(node, &node_key, slot); |
| BUG_ON(comp_keys(&node_key, &cpukey) >= 0); |
| } |
| return 0; |
| } |
| |
| /* |
| * extra checking to make sure all the items in a leaf are |
| * well formed and in the proper order |
| */ |
| static int check_leaf(struct btrfs_root *root, struct btrfs_path *path, |
| int level) |
| { |
| struct extent_buffer *leaf = path->nodes[level]; |
| struct extent_buffer *parent = NULL; |
| int parent_slot; |
| struct btrfs_key cpukey; |
| struct btrfs_disk_key parent_key; |
| struct btrfs_disk_key leaf_key; |
| int slot = path->slots[0]; |
| |
| u32 nritems = btrfs_header_nritems(leaf); |
| |
| if (path->nodes[level + 1]) |
| parent = path->nodes[level + 1]; |
| |
| if (nritems == 0) |
| return 0; |
| |
| if (parent) { |
| parent_slot = path->slots[level + 1]; |
| btrfs_node_key(parent, &parent_key, parent_slot); |
| btrfs_item_key(leaf, &leaf_key, 0); |
| |
| BUG_ON(memcmp(&parent_key, &leaf_key, |
| sizeof(struct btrfs_disk_key))); |
| BUG_ON(btrfs_node_blockptr(parent, parent_slot) != |
| btrfs_header_bytenr(leaf)); |
| } |
| if (slot != 0 && slot < nritems - 1) { |
| btrfs_item_key(leaf, &leaf_key, slot); |
| btrfs_item_key_to_cpu(leaf, &cpukey, slot - 1); |
| if (comp_keys(&leaf_key, &cpukey) <= 0) { |
| btrfs_print_leaf(root, leaf); |
| printk(KERN_CRIT "slot %d offset bad key\n", slot); |
| BUG_ON(1); |
| } |
| if (btrfs_item_offset_nr(leaf, slot - 1) != |
| btrfs_item_end_nr(leaf, slot)) { |
| btrfs_print_leaf(root, leaf); |
| printk(KERN_CRIT "slot %d offset bad\n", slot); |
| BUG_ON(1); |
| } |
| } |
| if (slot < nritems - 1) { |
| btrfs_item_key(leaf, &leaf_key, slot); |
| btrfs_item_key_to_cpu(leaf, &cpukey, slot + 1); |
| BUG_ON(comp_keys(&leaf_key, &cpukey) >= 0); |
| if (btrfs_item_offset_nr(leaf, slot) != |
| btrfs_item_end_nr(leaf, slot + 1)) { |
| btrfs_print_leaf(root, leaf); |
| printk(KERN_CRIT "slot %d offset bad\n", slot); |
| BUG_ON(1); |
| } |
| } |
| BUG_ON(btrfs_item_offset_nr(leaf, 0) + |
| btrfs_item_size_nr(leaf, 0) != BTRFS_LEAF_DATA_SIZE(root)); |
| return 0; |
| } |
| |
| static noinline int check_block(struct btrfs_root *root, |
| struct btrfs_path *path, int level) |
| { |
| return 0; |
| if (level == 0) |
| return check_leaf(root, path, level); |
| return check_node(root, path, level); |
| } |
| |
| /* |
| * 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 *map_token = NULL; |
| 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 (!map_token || offset < map_start || |
| (offset + sizeof(struct btrfs_disk_key)) > |
| map_start + map_len) { |
| if (map_token) { |
| unmap_extent_buffer(eb, map_token, KM_USER0); |
| map_token = NULL; |
| } |
| |
| err = map_private_extent_buffer(eb, offset, |
| sizeof(struct btrfs_disk_key), |
| &map_token, &kaddr, |
| &map_start, &map_len, KM_USER0); |
| |
| 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; |
| if (map_token) |
| unmap_extent_buffer(eb, map_token, KM_USER0); |
| return 0; |
| } |
| } |
| *slot = low; |
| if (map_token) |
| unmap_extent_buffer(eb, map_token, KM_USER0); |
| 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); |
| } |
| |
| /* 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]; |
| int err_on_enospc = 0; |
| u64 orig_ptr; |
| |
| if (level == 0) |
| return 0; |
| |
| mid = path->nodes[level]; |
| |
| WARN_ON(!path->locks[level]); |
| 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); |
| BUG_ON(!child); |
| btrfs_tree_lock(child); |
| btrfs_set_lock_blocking(child); |
| ret = btrfs_cow_block(trans, root, child, mid, 0, &child); |
| BUG_ON(ret); |
| |
| spin_lock(&root->node_lock); |
| root->node = child; |
| spin_unlock(&root->node_lock); |
| |
| 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); |
| ret = btrfs_free_extent(trans, root, mid->start, mid->len, |
| 0, root->root_key.objectid, level, 1); |
| /* once for the root ptr */ |
| free_extent_buffer(mid); |
| return ret; |
| } |
| if (btrfs_header_nritems(mid) > |
| BTRFS_NODEPTRS_PER_BLOCK(root) / 4) |
| return 0; |
| |
| if (btrfs_header_nritems(mid) < 2) |
| err_on_enospc = 1; |
| |
| 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; |
| if (btrfs_header_nritems(mid) < 2) |
| err_on_enospc = 1; |
| } |
| |
| /* |
| * 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) { |
| u64 bytenr = right->start; |
| u32 blocksize = right->len; |
| |
| clean_tree_block(trans, root, right); |
| btrfs_tree_unlock(right); |
| free_extent_buffer(right); |
| right = NULL; |
| wret = del_ptr(trans, root, path, level + 1, pslot + |
| 1); |
| if (wret) |
| ret = wret; |
| wret = btrfs_free_extent(trans, root, bytenr, |
| blocksize, 0, |
| root->root_key.objectid, |
| level, 0); |
| if (wret) |
| ret = wret; |
| } 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 |
| */ |
| BUG_ON(!left); |
| 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) { |
| /* we've managed to empty the middle node, drop it */ |
| u64 bytenr = mid->start; |
| u32 blocksize = mid->len; |
| |
| clean_tree_block(trans, root, mid); |
| btrfs_tree_unlock(mid); |
| free_extent_buffer(mid); |
| mid = NULL; |
| wret = del_ptr(trans, root, path, level + 1, pslot); |
| if (wret) |
| ret = wret; |
| wret = btrfs_free_extent(trans, root, bytenr, blocksize, |
| 0, root->root_key.objectid, |
| level, 0); |
| if (wret) |
| ret = wret; |
| } 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 */ |
| check_block(root, path, level); |
| 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]; |
| u64 orig_ptr; |
| |
| if (level == 0) |
| return 1; |
| |
| mid = path->nodes[level]; |
| 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]; |
| |
| 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; |
| 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)) { |
| readahead_tree_block(root, search, blocksize, |
| btrfs_node_ptr_generation(node, nr)); |
| 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 (eb && btrfs_buffer_uptodate(eb, gen)) |
| 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)) |
| block2 = 0; |
| free_extent_buffer(eb); |
| } |
| if (block1 || block2) { |
| ret = -EAGAIN; |
| |
| /* release the whole path */ |
| btrfs_release_path(root, 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 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(t); |
| path->locks[i] = 0; |
| } |
| } |
| } |
| |
| /* |
| * 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(path->nodes[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 && btrfs_buffer_uptodate(tmp, gen)) { |
| /* |
| * we found an up to date block without sleeping, return |
| * right away |
| */ |
| *eb_ret = tmp; |
| return 0; |
| } |
| |
| /* |
| * 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); |
| |
| if (tmp) |
| free_extent_buffer(tmp); |
| if (p->reada) |
| reada_for_search(root, p, level, slot, key->objectid); |
| |
| btrfs_release_path(NULL, p); |
| |
| ret = -EAGAIN; |
| tmp = read_tree_block(root, blocknr, blocksize, gen); |
| 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)) |
| 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 ret; |
| if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >= |
| BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { |
| int sret; |
| |
| 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); |
| |
| 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; |
| |
| 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); |
| |
| if (sret) { |
| ret = sret; |
| goto done; |
| } |
| b = p->nodes[level]; |
| if (!b) { |
| btrfs_release_path(NULL, 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; |
| u8 lowest_level = 0; |
| |
| 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; |
| |
| again: |
| if (p->search_commit_root) { |
| b = root->commit_root; |
| extent_buffer_get(b); |
| if (!p->skip_locking) |
| btrfs_tree_lock(b); |
| } else { |
| if (p->skip_locking) |
| b = btrfs_root_node(root); |
| else |
| b = btrfs_lock_root_node(root); |
| } |
| |
| while (b) { |
| level = btrfs_header_level(b); |
| |
| /* |
| * setup the path here so we can release it under lock |
| * contention with the cow code |
| */ |
| p->nodes[level] = b; |
| if (!p->skip_locking) |
| p->locks[level] = 1; |
| |
| 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); |
| |
| err = btrfs_cow_block(trans, root, b, |
| p->nodes[level + 1], |
| p->slots[level + 1], &b); |
| if (err) { |
| free_extent_buffer(b); |
| ret = err; |
| goto done; |
| } |
| } |
| cow_done: |
| BUG_ON(!cow && ins_len); |
| if (level != btrfs_header_level(b)) |
| WARN_ON(1); |
| level = btrfs_header_level(b); |
| |
| p->nodes[level] = b; |
| if (!p->skip_locking) |
| p->locks[level] = 1; |
| |
| btrfs_clear_path_blocking(p, NULL); |
| |
| /* |
| * 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 = check_block(root, p, level); |
| if (ret) { |
| ret = -1; |
| goto done; |
| } |
| |
| 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); |
| if (err == -EAGAIN) |
| goto again; |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| b = p->nodes[level]; |
| slot = p->slots[level]; |
| |
| unlock_up(p, level, lowest_unlock); |
| |
| 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) { |
| btrfs_clear_path_blocking(p, NULL); |
| err = btrfs_try_spin_lock(b); |
| |
| if (!err) { |
| btrfs_set_path_blocking(p); |
| btrfs_tree_lock(b); |
| btrfs_clear_path_blocking(p, b); |
| } |
| } |
| } else { |
| p->slots[level] = slot; |
| if (ins_len > 0 && |
| btrfs_leaf_free_space(root, b) < ins_len) { |
| btrfs_set_path_blocking(p); |
| err = split_leaf(trans, root, key, |
| p, ins_len, ret == 0); |
| btrfs_clear_path_blocking(p, NULL); |
| |
| BUG_ON(err > 0); |
| if (err) { |
| ret = err; |
| goto done; |
| } |
| } |
| if (!p->search_for_split) |
| unlock_up(p, level, lowest_unlock); |
| 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(root, 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 |
| * |
| * If this fails to write a tree block, it returns -1, but continues |
| * fixing up the blocks in ram so the tree is consistent. |
| */ |
| static int 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; |
| int ret = 0; |
| 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; |
| } |
| return ret; |
| } |
| |
| /* |
| * update item key. |
| * |
| * This function isn't completely safe. It's the caller's responsibility |
| * that the new key won't break the order |
| */ |
| int 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); |
| if (comp_keys(&disk_key, new_key) >= 0) |
| return -1; |
| } |
| if (slot < btrfs_header_nritems(eb) - 1) { |
| btrfs_item_key(eb, &disk_key, slot + 1); |
| if (comp_keys(&disk_key, new_key) <= 0) |
| return -1; |
| } |
| |
| 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); |
| return 0; |
| } |
| |
| /* |
| * 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); |
| if (IS_ERR(c)) |
| return PTR_ERR(c); |
| |
| 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); |
| |
| spin_lock(&root->node_lock); |
| old = root->node; |
| root->node = c; |
| spin_unlock(&root->node_lock); |
| |
| /* 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] = 1; |
| 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. |
| * |
| * returns zero on success and < 0 on any error |
| */ |
| static int 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]); |
| lower = path->nodes[level]; |
| nritems = btrfs_header_nritems(lower); |
| BUG_ON(slot > nritems); |
| if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root)) |
| BUG(); |
| 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); |
| return 0; |
| } |
| |
| /* |
| * 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; |
| int wret; |
| 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); |
| if (IS_ERR(split)) |
| return PTR_ERR(split); |
| |
| 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); |
| |
| wret = insert_ptr(trans, root, path, &disk_key, split->start, |
| path->slots[level + 1] + 1, |
| level + 1); |
| if (wret) |
| ret = wret; |
| |
| 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; |
| } |
| |
| 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) |
| { |
| struct extent_buffer *left = path->nodes[0]; |
| struct extent_buffer *upper = path->nodes[1]; |
| 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; |
| |
| if (empty) |
| nr = 0; |
| else |
| nr = 1; |
| |
| 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; |
| |
| if (!left->map_token) { |
| map_extent_buffer(left, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &left->map_token, &left->kaddr, |
| &left->map_start, &left->map_len, |
| KM_USER1); |
| } |
| |
| 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 (left->map_token) { |
| unmap_extent_buffer(left, left->map_token, KM_USER1); |
| left->map_token = NULL; |
| } |
| |
| 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); |
| if (!right->map_token) { |
| map_extent_buffer(right, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &right->map_token, &right->kaddr, |
| &right->map_start, &right->map_len, |
| KM_USER1); |
| } |
| push_space -= btrfs_item_size(right, item); |
| btrfs_set_item_offset(right, item, push_space); |
| } |
| |
| if (right->map_token) { |
| unmap_extent_buffer(right, right->map_token, KM_USER1); |
| right->map_token = NULL; |
| } |
| left_nritems -= push_items; |
| btrfs_set_header_nritems(left, left_nritems); |
| |
| if (left_nritems) |
| btrfs_mark_buffer_dirty(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. |
| */ |
| static 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 *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); |
| 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, data_size, empty, |
| right, free_space, left_nritems); |
| 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 |
| */ |
| 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, int right_nritems) |
| { |
| struct btrfs_disk_key disk_key; |
| struct extent_buffer *right = path->nodes[0]; |
| int slot; |
| int i; |
| int push_space = 0; |
| int push_items = 0; |
| struct btrfs_item *item; |
| u32 old_left_nritems; |
| u32 nr; |
| int ret = 0; |
| int wret; |
| u32 this_item_size; |
| u32 old_left_item_size; |
| |
| slot = path->slots[1]; |
| |
| if (empty) |
| nr = right_nritems; |
| else |
| nr = right_nritems - 1; |
| |
| for (i = 0; i < nr; i++) { |
| item = btrfs_item_nr(right, i); |
| if (!right->map_token) { |
| map_extent_buffer(right, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &right->map_token, &right->kaddr, |
| &right->map_start, &right->map_len, |
| KM_USER1); |
| } |
| |
| 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 (right->map_token) { |
| unmap_extent_buffer(right, right->map_token, KM_USER1); |
| right->map_token = NULL; |
| } |
| |
| 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); |
| if (!left->map_token) { |
| map_extent_buffer(left, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &left->map_token, &left->kaddr, |
| &left->map_start, &left->map_len, |
| KM_USER1); |
| } |
| |
| ioff = btrfs_item_offset(left, item); |
| btrfs_set_item_offset(left, item, |
| ioff - (BTRFS_LEAF_DATA_SIZE(root) - old_left_item_size)); |
| } |
| btrfs_set_header_nritems(left, old_left_nritems + push_items); |
| if (left->map_token) { |
| unmap_extent_buffer(left, left->map_token, KM_USER1); |
| left->map_token = NULL; |
| } |
| |
| /* 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); |
| |
| if (!right->map_token) { |
| map_extent_buffer(right, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &right->map_token, &right->kaddr, |
| &right->map_start, &right->map_len, |
| KM_USER1); |
| } |
| |
| push_space = push_space - btrfs_item_size(right, item); |
| btrfs_set_item_offset(right, item, push_space); |
| } |
| if (right->map_token) { |
| unmap_extent_buffer(right, right->map_token, KM_USER1); |
| right->map_token = NULL; |
| } |
| |
| btrfs_mark_buffer_dirty(left); |
| if (right_nritems) |
| btrfs_mark_buffer_dirty(right); |
| |
| btrfs_item_key(right, &disk_key, 0); |
| wret = fixup_low_keys(trans, root, path, &disk_key, 1); |
| if (wret) |
| ret = wret; |
| |
| /* then fixup the leaf pointer in the path */ |
| if (path->slots[0] < push_items) { |
| path->slots[0] += old_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] = 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 |
| */ |
| static 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 *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); |
| 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 */ |
| 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, data_size, |
| empty, left, free_space, right_nritems); |
| 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. |
| * |
| * returns 0 if all went well and < 0 on failure. |
| */ |
| static noinline int 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; |
| int ret = 0; |
| int wret; |
| struct btrfs_disk_key disk_key; |
| |
| 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; |
| |
| if (!right->map_token) { |
| map_extent_buffer(right, (unsigned long)item, |
| sizeof(struct btrfs_item), |
| &right->map_token, &right->kaddr, |
| &right->map_start, &right->map_len, |
| KM_USER1); |
| } |
| |
| ioff = btrfs_item_offset(right, item); |
| btrfs_set_item_offset(right, item, ioff + rt_data_off); |
| } |
| |
| if (right->map_token) { |
| unmap_extent_buffer(right, right->map_token, KM_USER1); |
| right->map_token = NULL; |
| } |
| |
| btrfs_set_header_nritems(l, mid); |
| ret = 0; |
| btrfs_item_key(right, &disk_key, 0); |
| wret = insert_ptr(trans, root, path, &disk_key, right->start, |
| path->slots[1] + 1, 1); |
| if (wret) |
| ret = wret; |
| |
| 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); |
| |
| 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. |
| * |
| * 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; |
| |
| 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 && ins_key->type != BTRFS_DIR_ITEM_KEY) { |
| wret = push_leaf_right(trans, root, path, data_size, 0); |
| if (wret < 0) |
| return wret; |
| if (wret) { |
| wret = push_leaf_left(trans, root, path, data_size, 0); |
| 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)) { |
| 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)) { |
| 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); |
| if (IS_ERR(right)) { |
| BUG_ON(1); |
| return PTR_ERR(right); |
| } |
| |
| 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); |
| wret = insert_ptr(trans, root, path, |
| &disk_key, right->start, |
| path->slots[1] + 1, 1); |
| if (wret) |
| ret = wret; |
| |
| 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); |
| wret = insert_ptr(trans, root, path, |
| &disk_key, |
| right->start, |
| path->slots[1], 1); |
| if (wret) |
| ret = wret; |
| 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) { |
| wret = fixup_low_keys(trans, root, |
| path, &disk_key, 1); |
| if (wret) |
| ret = wret; |
| } |
| } |
| btrfs_mark_buffer_dirty(right); |
| return ret; |
| } |
| |
| ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems); |
| BUG_ON(ret); |
| |
| if (split == 2) { |
| BUG_ON(num_doubles != 0); |
| num_doubles++; |
| goto again; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * 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
|