diff options
Diffstat (limited to 'ctree.c')
| -rw-r--r-- | ctree.c | 2940 |
1 files changed, 2940 insertions, 0 deletions
diff --git a/ctree.c b/ctree.c new file mode 100644 index 00000000..04cc476e --- /dev/null +++ b/ctree.c @@ -0,0 +1,2940 @@ +/* + * Copyright (C) 2007 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 "ctree.h" +#include "disk-io.h" +#include "transaction.h" +#include "print-tree.h" +#include "repair.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); + +inline void btrfs_init_path(struct btrfs_path *p) +{ + memset(p, 0, sizeof(*p)); +} + +struct btrfs_path *btrfs_alloc_path(void) +{ + struct btrfs_path *path; + path = kzalloc(sizeof(struct btrfs_path), GFP_NOFS); + return path; +} + +void btrfs_free_path(struct btrfs_path *p) +{ + if (!p) + return; + btrfs_release_path(p); + kfree(p); +} + +void btrfs_release_path(struct btrfs_path *p) +{ + int i; + for (i = 0; i < BTRFS_MAX_LEVEL; i++) { + if (!p->nodes[i]) + continue; + free_extent_buffer(p->nodes[i]); + } + memset(p, 0, sizeof(*p)); +} + +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); + } +} + +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_root *new_root; + struct btrfs_disk_key disk_key; + + new_root = kmalloc(sizeof(*new_root), GFP_NOFS); + if (!new_root) + return -ENOMEM; + + memcpy(new_root, root, sizeof(*new_root)); + new_root->root_key.objectid = new_root_objectid; + + 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, new_root, buf->len, + new_root_objectid, &disk_key, + level, buf->start, 0); + if (IS_ERR(cow)) { + kfree(new_root); + 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, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + + WARN_ON(btrfs_header_generation(buf) > trans->transid); + ret = btrfs_inc_ref(trans, new_root, cow, 0); + kfree(new_root); + + 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 + */ +static 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, + btrfs_header_level(buf), 1, + &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(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) && + owner == BTRFS_TREE_RELOC_OBJECTID); + + 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_block_flags(trans, root, buf->start, + btrfs_header_level(buf), + new_flags); + 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; +} + +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 extent_buffer *cow; + struct btrfs_disk_key disk_key; + int level; + + 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, + root->root_key.objectid, &disk_key, + level, search_start, empty_size); + 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 (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, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + + WARN_ON(!(buf->flags & EXTENT_BAD_TRANSID) && + btrfs_header_generation(buf) > trans->transid); + + update_ref_for_cow(trans, root, buf, cow); + + if (buf == root->node) { + root->node = cow; + extent_buffer_get(cow); + + btrfs_free_extent(trans, root, buf->start, buf->len, + 0, root->root_key.objectid, level, 0); + free_extent_buffer(buf); + add_root_to_dirty_list(root); + } else { + btrfs_set_node_blockptr(parent, parent_slot, + cow->start); + WARN_ON(trans->transid == 0); + btrfs_set_node_ptr_generation(parent, parent_slot, + trans->transid); + btrfs_mark_buffer_dirty(parent); + WARN_ON(btrfs_header_generation(parent) != trans->transid); + + btrfs_free_extent(trans, root, buf->start, buf->len, + 0, root->root_key.objectid, level, 1); + } + if (!list_empty(&buf->recow)) { + list_del_init(&buf->recow); + free_extent_buffer(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; +} + +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 %Lu running %Lu\n", trans->transid, + 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); + ret = __btrfs_cow_block(trans, root, buf, parent, + parent_slot, cow_ret, search_start, 0); + return ret; +} + +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; +} + +/* + * compare two keys in a memcmp fashion + */ +static int btrfs_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); +} + +/* + * 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); +} + +enum btrfs_tree_block_status +btrfs_check_node(struct btrfs_root *root, struct btrfs_disk_key *parent_key, + struct extent_buffer *buf) +{ + int i; + struct btrfs_key cpukey; + struct btrfs_disk_key key; + u32 nritems = btrfs_header_nritems(buf); + enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS; + + if (nritems == 0 || nritems > BTRFS_NODEPTRS_PER_BLOCK(root)) + goto fail; + + ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY; + if (parent_key && parent_key->type) { + btrfs_node_key(buf, &key, 0); + if (memcmp(parent_key, &key, sizeof(key))) + goto fail; + } + ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER; + for (i = 0; nritems > 1 && i < nritems - 2; i++) { + btrfs_node_key(buf, &key, i); + btrfs_node_key_to_cpu(buf, &cpukey, i + 1); + if (btrfs_comp_keys(&key, &cpukey) >= 0) + goto fail; + } + return BTRFS_TREE_BLOCK_CLEAN; +fail: + if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) { + if (parent_key) + btrfs_disk_key_to_cpu(&cpukey, parent_key); + else + btrfs_node_key_to_cpu(buf, &cpukey, 0); + btrfs_add_corrupt_extent_record(root->fs_info, &cpukey, + buf->start, buf->len, + btrfs_header_level(buf)); + } + return ret; +} + +enum btrfs_tree_block_status +btrfs_check_leaf(struct btrfs_root *root, struct btrfs_disk_key *parent_key, + struct extent_buffer *buf) +{ + int i; + struct btrfs_key cpukey; + struct btrfs_disk_key key; + u32 nritems = btrfs_header_nritems(buf); + enum btrfs_tree_block_status ret = BTRFS_TREE_BLOCK_INVALID_NRITEMS; + + if (nritems * sizeof(struct btrfs_item) > buf->len) { + fprintf(stderr, "invalid number of items %llu\n", + (unsigned long long)buf->start); + goto fail; + } + + if (btrfs_header_level(buf) != 0) { + ret = BTRFS_TREE_BLOCK_INVALID_LEVEL; + fprintf(stderr, "leaf is not a leaf %llu\n", + (unsigned long long)btrfs_header_bytenr(buf)); + goto fail; + } + if (btrfs_leaf_free_space(root, buf) < 0) { + ret = BTRFS_TREE_BLOCK_INVALID_FREE_SPACE; + fprintf(stderr, "leaf free space incorrect %llu %d\n", + (unsigned long long)btrfs_header_bytenr(buf), + btrfs_leaf_free_space(root, buf)); + goto fail; + } + + if (nritems == 0) + return BTRFS_TREE_BLOCK_CLEAN; + + btrfs_item_key(buf, &key, 0); + if (parent_key && parent_key->type && + memcmp(parent_key, &key, sizeof(key))) { + ret = BTRFS_TREE_BLOCK_INVALID_PARENT_KEY; + fprintf(stderr, "leaf parent key incorrect %llu\n", + (unsigned long long)btrfs_header_bytenr(buf)); + goto fail; + } + for (i = 0; nritems > 1 && i < nritems - 1; i++) { + btrfs_item_key(buf, &key, i); + btrfs_item_key_to_cpu(buf, &cpukey, i + 1); + if (btrfs_comp_keys(&key, &cpukey) >= 0) { + ret = BTRFS_TREE_BLOCK_BAD_KEY_ORDER; + fprintf(stderr, "bad key ordering %d %d\n", i, i+1); + goto fail; + } + if (btrfs_item_offset_nr(buf, i) != + btrfs_item_end_nr(buf, i + 1)) { + ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS; + fprintf(stderr, "incorrect offsets %u %u\n", + btrfs_item_offset_nr(buf, i), + btrfs_item_end_nr(buf, i + 1)); + goto fail; + } + if (i == 0 && btrfs_item_end_nr(buf, i) != + BTRFS_LEAF_DATA_SIZE(root)) { + ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS; + fprintf(stderr, "bad item end %u wanted %u\n", + btrfs_item_end_nr(buf, i), + (unsigned)BTRFS_LEAF_DATA_SIZE(root)); + goto fail; + } + } + + for (i = 0; i < nritems; i++) { + if (btrfs_item_end_nr(buf, i) > BTRFS_LEAF_DATA_SIZE(root)) { + btrfs_item_key(buf, &key, 0); + btrfs_print_key(&key); + fflush(stdout); + ret = BTRFS_TREE_BLOCK_INVALID_OFFSETS; + fprintf(stderr, "slot end outside of leaf %llu > %llu\n", + (unsigned long long)btrfs_item_end_nr(buf, i), + (unsigned long long)BTRFS_LEAF_DATA_SIZE(root)); + goto fail; + } + } + + return BTRFS_TREE_BLOCK_CLEAN; +fail: + if (btrfs_header_owner(buf) == BTRFS_EXTENT_TREE_OBJECTID) { + if (parent_key) + btrfs_disk_key_to_cpu(&cpukey, parent_key); + else + btrfs_item_key_to_cpu(buf, &cpukey, 0); + + btrfs_add_corrupt_extent_record(root->fs_info, &cpukey, + buf->start, buf->len, 0); + } + return ret; +} + +static int noinline check_block(struct btrfs_root *root, + struct btrfs_path *path, int level) +{ + struct btrfs_disk_key key; + struct btrfs_disk_key *key_ptr = NULL; + struct extent_buffer *parent; + enum btrfs_tree_block_status ret; + + if (path->skip_check_block) + return 0; + if (path->nodes[level + 1]) { + parent = path->nodes[level + 1]; + btrfs_node_key(parent, &key, path->slots[level + 1]); + key_ptr = &key; + } + if (level == 0) + ret = btrfs_check_leaf(root, key_ptr, path->nodes[0]); + else + ret = btrfs_check_node(root, key_ptr, path->nodes[level]); + if (ret == BTRFS_TREE_BLOCK_CLEAN) + return 0; + return -EIO; +} + +/* + * 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 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; + unsigned long offset; + struct btrfs_disk_key *tmp; + + while(low < high) { + mid = (low + high) / 2; + offset = p + mid * item_size; + + tmp = (struct btrfs_disk_key *)(eb->data + offset); + ret = btrfs_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); +} + +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; + + if (level == 0) + return NULL; + + return read_tree_block(root, btrfs_node_blockptr(parent, slot), + btrfs_level_size(root, level - 1), + btrfs_node_ptr_generation(parent, slot)); +} + +static 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(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(!extent_buffer_uptodate(child)); + ret = btrfs_cow_block(trans, root, child, mid, 0, &child); + BUG_ON(ret); + + root->node = child; + add_root_to_dirty_list(root); + path->nodes[level] = NULL; + clean_tree_block(trans, root, mid); + wait_on_tree_block_writeback(root, 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; + + left = read_node_slot(root, parent, pslot - 1); + if (extent_buffer_uptodate(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 (extent_buffer_uptodate(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; + } + + /* + * 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); + wait_on_tree_block_writeback(root, right); + free_extent_buffer(right); + right = NULL; + wret = btrfs_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); + wait_on_tree_block_writeback(root, mid); + free_extent_buffer(mid); + mid = NULL; + wret = btrfs_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); + path->nodes[level] = left; + path->slots[level + 1] -= 1; + path->slots[level] = orig_slot; + if (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) + free_extent_buffer(right); + if (left) + free_extent_buffer(left); + return ret; +} + +/* returns zero if the push worked, non-zero otherwise */ +static int noinline 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 (extent_buffer_uptodate(left)) { + u32 left_nr; + 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; + free_extent_buffer(mid); + } else { + orig_slot -= + btrfs_header_nritems(left); + path->slots[level] = orig_slot; + free_extent_buffer(left); + } + return 0; + } + free_extent_buffer(left); + } + right= read_node_slot(root, parent, pslot + 1); + + /* + * then try to empty the right most buffer into the middle + */ + if (extent_buffer_uptodate(right)) { + u32 right_nr; + 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); + free_extent_buffer(mid); + } else { + free_extent_buffer(right); + } + return 0; + } + free_extent_buffer(right); + } + return 1; +} + +/* + * readahead one full node of leaves + */ +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 lowest_read; + u64 highest_read; + 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; + } + + highest_read = search; + lowest_read = 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 >= lowest_read && search <= highest_read) || + (search < lowest_read && lowest_read - search <= 32768) || + (search > highest_read && search - highest_read <= 32768)) { + readahead_tree_block(root, search, blocksize, + btrfs_node_ptr_generation(node, nr)); + nread += blocksize; + } + nscan++; + if (path->reada < 2 && (nread > (256 * 1024) || nscan > 32)) + break; + if(nread > (1024 * 1024) || nscan > 128) + break; + + if (search < lowest_read) + lowest_read = search; + if (search > highest_read) + highest_read = search; + } +} + +int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *found_path, + u64 iobjectid, u64 ioff, u8 key_type, + struct btrfs_key *found_key) +{ + int ret; + struct btrfs_key key; + struct extent_buffer *eb; + struct btrfs_path *path; + + key.type = key_type; + key.objectid = iobjectid; + key.offset = ioff; + + if (found_path == NULL) { + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + } else + path = found_path; + + ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0); + if ((ret < 0) || (found_key == NULL)) + goto out; + + eb = path->nodes[0]; + if (ret && path->slots[0] >= btrfs_header_nritems(eb)) { + ret = btrfs_next_leaf(fs_root, path); + if (ret) + goto out; + eb = path->nodes[0]; + } + + btrfs_item_key_to_cpu(eb, found_key, path->slots[0]); + if (found_key->type != key.type || + found_key->objectid != key.objectid) { + ret = 1; + goto out; + } + +out: + if (path != found_path) + btrfs_free_path(path); + 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 level; + int should_reada = p->reada; + u8 lowest_level = 0; + + lowest_level = p->lowest_level; + WARN_ON(lowest_level && ins_len > 0); + WARN_ON(p->nodes[0] != NULL); + /* + WARN_ON(!mutex_is_locked(&root->fs_info->fs_mutex)); + */ +again: + b = root->node; + extent_buffer_get(b); + while (b) { + level = btrfs_header_level(b); + if (cow) { + int wret; + wret = btrfs_cow_block(trans, root, b, + p->nodes[level + 1], + p->slots[level + 1], + &b); + if (wret) { + free_extent_buffer(b); + return wret; + } + } + BUG_ON(!cow && ins_len); + if (level != btrfs_header_level(b)) + WARN_ON(1); + level = btrfs_header_level(b); + p->nodes[level] = b; + ret = check_block(root, p, level); + if (ret) + return -1; + ret = bin_search(b, key, level, &slot); + if (level != 0) { + if (ret && slot > 0) + slot -= 1; + p->slots[level] = slot; + if ((p->search_for_split || ins_len > 0) && + btrfs_header_nritems(b) >= + BTRFS_NODEPTRS_PER_BLOCK(root) - 3) { + int sret = split_node(trans, root, p, level); + BUG_ON(sret > 0); + if (sret) + return sret; + b = p->nodes[level]; + slot = p->slots[level]; + } else if (ins_len < 0) { + int sret = balance_level(trans, root, p, + level); + if (sret) + return sret; + b = p->nodes[level]; + if (!b) { + btrfs_release_path(p); + goto again; + } + slot = p->slots[level]; + BUG_ON(btrfs_header_nritems(b) == 1); + } + /* this is only true while dropping a snapshot */ + if (level == lowest_level) + break; + + if (should_reada) + reada_for_search(root, p, level, slot, + key->objectid); + + b = read_node_slot(root, b, slot); + if (!extent_buffer_uptodate(b)) + return -EIO; + } else { + p->slots[level] = slot; + if (ins_len > 0 && + ins_len > btrfs_leaf_free_space(root, b)) { + int sret = split_leaf(trans, root, key, + p, ins_len, ret == 0); + BUG_ON(sret > 0); + if (sret) + return sret; + } + return ret; + } + } + return 1; +} + +/* + * 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 + */ +void btrfs_fixup_low_keys(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 + */ +int btrfs_set_item_key_safe(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 (btrfs_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 (btrfs_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) + btrfs_fixup_low_keys(root, path, &disk_key, 1); + return 0; +} + +/* + * update an item key without the safety checks. This is meant to be called by + * fsck only. + */ +void btrfs_set_item_key_unsafe(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]; + + 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) + btrfs_fixup_low_keys(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 int noinline 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, + 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, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + + write_extent_buffer(c, root->fs_info->chunk_tree_uuid, + 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; + 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->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); + if (slot > nritems) + BUG(); + 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 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, + 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, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + write_extent_buffer(split, root->fs_info->chunk_tree_uuid, + 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; + free_extent_buffer(c); + path->nodes[level] = split; + path->slots[level + 1] += 1; + } else { + 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 + */ +int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf) +{ + u32 nodesize = (root ? BTRFS_LEAF_DATA_SIZE(root) : leaf->len); + int nritems = btrfs_header_nritems(leaf); + int ret; + ret = nodesize - leaf_space_used(leaf, 0, nritems); + if (ret < 0) { + printk("leaf free space ret %d, leaf data size %u, used %d nritems %d\n", + ret, nodesize, leaf_space_used(leaf, 0, nritems), + nritems); + } + return ret; +} + +/* + * 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; + struct btrfs_disk_key disk_key; + int slot; + u32 i; + int free_space; + int push_space = 0; + int push_items = 0; + struct btrfs_item *item; + u32 left_nritems; + u32 nr; + u32 right_nritems; + u32 data_end; + u32 this_item_size; + int ret; + + slot = path->slots[1]; + if (!path->nodes[1]) { + return 1; + } + upper = path->nodes[1]; + if (slot >= btrfs_header_nritems(upper) - 1) + return 1; + + right = read_node_slot(root, upper, slot + 1); + if (!extent_buffer_uptodate(right)) { + if (IS_ERR(right)) + return PTR_ERR(right); + return -EIO; + } + free_space = btrfs_leaf_free_space(root, right); + if (free_space < data_size) { + free_extent_buffer(right); + return 1; + } + + /* cow and double check */ + ret = btrfs_cow_block(trans, root, right, upper, + slot + 1, &right); + if (ret) { + free_extent_buffer(right); + return 1; + } + free_space = btrfs_leaf_free_space(root, right); + if (free_space < data_size) { + free_extent_buffer(right); + return 1; + } + + left_nritems = btrfs_header_nritems(left); + if (left_nritems == 0) { + free_extent_buffer(right); + return 1; + } + + if (empty) + nr = 0; + else + nr = 1; + + i = left_nritems - 1; + while (i >= nr) { + item = btrfs_item_nr(i); + + if (path->slots[0] == i) + push_space += data_size + sizeof(*item); + + 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) { + free_extent_buffer(right); + return 1; + } + + 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(i); + push_space -= btrfs_item_size(right, item); + btrfs_set_item_offset(right, item, push_space); + } + + 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; + free_extent_buffer(path->nodes[0]); + path->nodes[0] = right; + path->slots[1] += 1; + } else { + free_extent_buffer(right); + } + return 0; +} +/* + * 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 btrfs_disk_key disk_key; + struct extent_buffer *right = path->nodes[0]; + struct extent_buffer *left; + int slot; + int i; + int free_space; + int push_space = 0; + int push_items = 0; + struct btrfs_item *item; + u32 old_left_nritems; + u32 right_nritems; + u32 nr; + int ret = 0; + u32 this_item_size; + u32 old_left_item_size; + + 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; + } + + left = read_node_slot(root, path->nodes[1], slot - 1); + free_space = btrfs_leaf_free_space(root, left); + if (free_space < data_size) { + free_extent_buffer(left); + return 1; + } + + /* 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 */ + free_extent_buffer(left); + return 1; + } + + free_space = btrfs_leaf_free_space(root, left); + if (free_space < data_size) { + free_extent_buffer(left); + return 1; + } + + if (empty) + nr = right_nritems; + else + nr = right_nritems - 1; + + for (i = 0; i < nr; i++) { + item = btrfs_item_nr(i); + + if (path->slots[0] == i) + push_space += data_size + sizeof(*item); + + 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) { + free_extent_buffer(left); + return 1; + } + 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(i); + 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); + + /* fixup right node */ + if (push_items > right_nritems) { + printk("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(i); + push_space = push_space - btrfs_item_size(right, item); + btrfs_set_item_offset(right, item, push_space); + } + + btrfs_mark_buffer_dirty(left); + if (right_nritems) + btrfs_mark_buffer_dirty(right); + + btrfs_item_key(right, &disk_key, 0); + btrfs_fixup_low_keys(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; + free_extent_buffer(path->nodes[0]); + path->nodes[0] = left; + path->slots[1] -= 1; + } else { + free_extent_buffer(left); + path->slots[0] -= push_items; + } + 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 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(i); + u32 ioff = btrfs_item_offset(right, item); + btrfs_set_item_offset(right, item, ioff + rt_data_off); + } + + 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) { + free_extent_buffer(path->nodes[0]); + path->nodes[0] = right; + path->slots[0] -= mid; + path->slots[1] += 1; + } else { + 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, + 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, + btrfs_header_fsid(), BTRFS_FSID_SIZE); + + write_extent_buffer(right, root->fs_info->chunk_tree_uuid, + 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; + + 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; + free_extent_buffer(path->nodes[0]); + path->nodes[0] = right; + path->slots[0] = 0; + if (path->slots[1] == 0) { + btrfs_fixup_low_keys(root, path, + &disk_key, 1); + } + } + 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 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) +{ + u32 item_size; + struct extent_buffer *leaf; + struct btrfs_key orig_key; + struct btrfs_item *item; + struct btrfs_item *new_item; + int ret = 0; + int slot; + u32 nritems; + u32 orig_offset; + struct btrfs_disk_key disk_key; + char *buf; + + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &orig_key, path->slots[0]); + if (btrfs_leaf_free_space(root, leaf) >= sizeof(struct btrfs_item)) + goto split; + + item_size = btrfs_item_size_nr(leaf, path->slots[0]); + btrfs_release_path(path); + + path->search_for_split = 1; + + ret = btrfs_search_slot(trans, root, &orig_key, path, 0, 1); + path->search_for_split = 0; + + /* if our item isn't there or got smaller, return now */ + if (ret != 0 || item_size != btrfs_item_size_nr(path->nodes[0], + path->slots[0])) { + return -EAGAIN; + } + + ret = split_leaf(trans, root, &orig_key, path, 0, 0); + BUG_ON(ret); + + BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item)); + leaf = path->nodes[0]; + +split: + item = btrfs_item_nr(path->slots[0]); + orig_offset = btrfs_item_offset(leaf, item); + item_size = btrfs_item_size(leaf, item); + + + buf = kmalloc(item_size, GFP_NOFS); + BUG_ON(!buf); + read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, + path->slots[0]), item_size); + slot = path->slots[0] + 1; + leaf = path->nodes[0]; + + 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(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); + + ret = 0; + if (btrfs_leaf_free_space(root, leaf) < 0) { + btrfs_print_leaf(root, leaf); + BUG(); + } + kfree(buf); + return ret; +} + +int btrfs_truncate_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + u32 new_size, int from_end) +{ + int ret = 0; + 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; + + leaf = path->nodes[0]; + slot = path->slots[0]; + + old_size = btrfs_item_size_nr(leaf, slot); + if (old_size == new_size) + return 0; + + 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(i); + ioff = btrfs_item_offset(leaf, item); + btrfs_set_item_offset(leaf, item, ioff + size_diff); + } + + /* 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) + btrfs_fixup_low_keys(root, path, &disk_key, 1); + } + + item = btrfs_item_nr(slot); + btrfs_set_item_size(leaf, item, new_size); + btrfs_mark_buffer_dirty(leaf); + + ret = 0; + if (btrfs_leaf_free_space(root, leaf) < 0) { + btrfs_print_leaf(root, leaf); + BUG(); + } + return ret; +} + +int btrfs_extend_item(struct btrfs_trans_handle *trans, + struct btrfs_root *root, struct btrfs_path *path, + u32 data_size) +{ + int ret = 0; + 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; + + 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("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(i); + ioff = btrfs_item_offset(leaf, item); + btrfs_set_item_offset(leaf, item, ioff - data_size); + } + + /* 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(slot); + btrfs_set_item_size(leaf, item, old_size + data_size); + btrfs_mark_buffer_dirty(leaf); + + ret = 0; + if (btrfs_leaf_free_space(root, leaf) < 0) { + btrfs_print_leaf(root, leaf); + BUG(); + } + return ret; +} + +/* + * 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_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) +{ + struct extent_buffer *leaf; + struct btrfs_item *item; + int ret = 0; + int slot; + int i; + u32 nritems; + u32 total_size = 0; + u32 total_data = 0; + unsigned int data_end; + struct btrfs_disk_key disk_key; + + for (i = 0; i < nr; i++) { + total_data += data_size[i]; + } + + /* create a root if there isn't one */ + if (!root->node) + BUG(); + + 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) + 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) { + btrfs_print_leaf(root, leaf); + printk("not enough freespace need %u have %d\n", + total_size, btrfs_leaf_free_space(root, leaf)); + BUG(); + } + + slot = path->slots[0]; + BUG_ON(slot < 0); + + if (slot != nritems) { + unsigned int old_data = btrfs_item_end_nr(leaf, slot); + + if (old_data < data_end) { + btrfs_print_leaf(root, leaf); + printk("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(i); + ioff = btrfs_item_offset(leaf, item); + btrfs_set_item_offset(leaf, item, ioff - total_data); + } + + /* 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(slot + i); + btrfs_set_item_offset(leaf, item, data_end - data_size[i]); + data_end -= data_size[i]; + btrfs_set_item_size(leaf, item, data_size[i]); + } + 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); + btrfs_fixup_low_keys(root, path, &disk_key, 1); + } + + if (btrfs_leaf_free_space(root, leaf) < 0) { + btrfs_print_leaf(root, leaf); + BUG(); + } + +out: + return ret; +} + +/* + * 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(); + BUG_ON(!path); + 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. + * + * If the delete empties a node, the node is removed from the tree, + * continuing all the way the root if required. The root is converted into + * a leaf if all the nodes are emptied. + */ +int btrfs_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; + int ret = 0; + + 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); + btrfs_fixup_low_keys(root, path, &disk_key, level + 1); + } + btrfs_mark_buffer_dirty(parent); + return ret; +} + +/* + * 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 int btrfs_del_leaf(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_path *path, + struct extent_buffer *leaf) +{ + int ret; + + WARN_ON(btrfs_header_generation(leaf) != trans->transid); + ret = btrfs_del_ptr(trans, root, path, 1, path->slots[1]); + if (ret) + return ret; + + ret = btrfs_free_extent(trans, root, leaf->start, leaf->len, + 0, root->root_key.objectid, 0, 0); + return ret; +} + +/* + * 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; + + 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(i); + ioff = btrfs_item_offset(leaf, item); + btrfs_set_item_offset(leaf, item, ioff + dsize); + } + + 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 { + clean_tree_block(trans, root, leaf); + wait_on_tree_block_writeback(root, leaf); + + wret = btrfs_del_leaf(trans, root, path, leaf); + BUG_ON(ret); + if (wret) + ret = wret; + } + } 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); + btrfs_fixup_low_keys(root, path, &disk_key, 1); + } + + /* delete the leaf if it is mostly empty */ + if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) { + /* 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); + + wret = push_leaf_left(trans, root, path, 1, 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); + if (wret < 0 && wret != -ENOSPC) + ret = wret; + } + + if (btrfs_header_nritems(leaf) == 0) { + clean_tree_block(trans, root, leaf); + wait_on_tree_block_writeback(root, leaf); + + path->slots[1] = slot; + ret = btrfs_del_leaf(trans, root, path, leaf); + BUG_ON(ret); + free_extent_buffer(leaf); + + } else { + btrfs_mark_buffer_dirty(leaf); + free_extent_buffer(leaf); + } + } else { + btrfs_mark_buffer_dirty(leaf); + } + } + return ret; +} + +/* + * walk up the tree as far as required to find the previous leaf. + * returns 0 if it found something or 1 if there are no lesser leaves. + * returns < 0 on io errors. + */ +int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path) +{ + int slot; + int level = 1; + struct extent_buffer *c; + struct extent_buffer *next = NULL; + + while(level < BTRFS_MAX_LEVEL) { + if (!path->nodes[level]) + return 1; + + slot = path->slots[level]; + c = path->nodes[level]; + if (slot == 0) { + level++; + if (level == BTRFS_MAX_LEVEL) + return 1; + continue; + } + slot--; + + next = read_node_slot(root, c, slot); + if (!extent_buffer_uptodate(next)) { + if (IS_ERR(next)) + return PTR_ERR(next); + return -EIO; + } + break; + } + path->slots[level] = slot; + while(1) { + level--; + c = path->nodes[level]; + free_extent_buffer(c); + slot = btrfs_header_nritems(next); + if (slot != 0) + slot--; + path->nodes[level] = next; + path->slots[level] = slot; + if (!level) + break; + next = read_node_slot(root, next, slot); + if (!extent_buffer_uptodate(next)) { + if (IS_ERR(next)) + return PTR_ERR(next); + return -EIO; + } + } + return 0; +} + +/* + * walk up the tree as far as required to find the next leaf. + * 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 = 1; + struct extent_buffer *c; + struct extent_buffer *next = NULL; + + while(level < BTRFS_MAX_LEVEL) { + if (!path->nodes[level]) + return 1; + + slot = path->slots[level] + 1; + c = path->nodes[level]; + if (slot >= btrfs_header_nritems(c)) { + level++; + if (level == BTRFS_MAX_LEVEL) + return 1; + continue; + } + + if (path->reada) + reada_for_search(root, path, level, slot, 0); + + next = read_node_slot(root, c, slot); + if (!extent_buffer_uptodate(next)) + return -EIO; + break; + } + path->slots[level] = slot; + while(1) { + level--; + c = path->nodes[level]; + free_extent_buffer(c); + path->nodes[level] = next; + path->slots[level] = 0; + if (!level) + break; + if (path->reada) + reada_for_search(root, path, level, 0, 0); + next = read_node_slot(root, next, 0); + if (!extent_buffer_uptodate(next)) + return -EIO; + } + return 0; +} + +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; + int ret; + + while(1) { + if (path->slots[0] == 0) { + ret = btrfs_prev_leaf(root, path); + if (ret != 0) + return ret; + } else { + path->slots[0]--; + } + leaf = path->nodes[0]; + btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); + if (found_key.type == type) + return 0; + } + return 1; +} + +/* + * search in extent tree to find a previous Metadata/Data extent item with + * min objecitd. + * + * returns 0 if something is found, 1 if nothing was found and < 0 on error + */ +int btrfs_previous_extent_item(struct btrfs_root *root, + struct btrfs_path *path, u64 min_objectid) +{ + struct btrfs_key found_key; + struct extent_buffer *leaf; + u32 nritems; + int ret; + + while (1) { + if (path->slots[0] == 0) { + 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 == BTRFS_EXTENT_ITEM_KEY || + found_key.type == BTRFS_METADATA_ITEM_KEY) + return 0; + if (found_key.objectid == min_objectid && + found_key.type < BTRFS_EXTENT_ITEM_KEY) + break; + } + return 1; +} |