/* * 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 #include #include "kernel-lib/bitops.h" #include "kernel-lib/sizes.h" #include "kernel-shared/ctree.h" #include "kernel-shared/disk-io.h" #include "kernel-shared/transaction.h" #include "kernel-shared/print-tree.h" #include "kernel-shared/tree-checker.h" #include "kernel-shared/volumes.h" #include "common/internal.h" #include "common/messages.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, const 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 extent_buffer *dst, struct extent_buffer *src, int empty); static int balance_node_right(struct btrfs_trans_handle *trans, struct extent_buffer *dst_buf, struct extent_buffer *src_buf); static const struct btrfs_csums { u16 size; const char name[10]; const char driver[12]; } btrfs_csums[] = { [BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" }, [BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" }, [BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" }, [BTRFS_CSUM_TYPE_BLAKE2] = { .size = 32, .name = "blake2b", .driver = "blake2b-256" }, }; /* * 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 unsigned int leaf_data_end(const struct extent_buffer *leaf) { u32 nr = btrfs_header_nritems(leaf); if (nr == 0) return BTRFS_LEAF_DATA_SIZE(leaf->fs_info); return btrfs_item_offset(leaf, nr - 1); } /* * Move data in a @leaf (using memmove, safe for overlapping ranges). * * @leaf: leaf that we're doing a memmove on * @dst_offset: item data offset we're moving to * @src_offset: item data offset were' moving from * @len: length of the data we're moving * * Wrapper around memmove_extent_buffer() that takes into account the header on * the leaf. The btrfs_item offset's start directly after the header, so we * have to adjust any offsets to account for the header in the leaf. This * handles that math to simplify the callers. */ static inline void memmove_leaf_data(const struct extent_buffer *leaf, unsigned long dst_offset, unsigned long src_offset, unsigned long len) { memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + dst_offset, btrfs_item_nr_offset(leaf, 0) + src_offset, len); } /* * Copy item data from @src into @dst at the given @offset. * * @dst: destination leaf that we're copying into * @src: source leaf that we're copying from * @dst_offset: item data offset we're copying to * @src_offset: item data offset were' copying from * @len: length of the data we're copying * * Wrapper around copy_extent_buffer() that takes into account the header on * the leaf. The btrfs_item offset's start directly after the header, so we * have to adjust any offsets to account for the header in the leaf. This * handles that math to simplify the callers. */ static inline void copy_leaf_data(const struct extent_buffer *dst, const struct extent_buffer *src, unsigned long dst_offset, unsigned long src_offset, unsigned long len) { copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, 0) + dst_offset, btrfs_item_nr_offset(src, 0) + src_offset, len); } /* * Move items in a @leaf (using memmove). * * @dst: destination leaf for the items * @dst_item: the item nr we're copying into * @src_item: the item nr we're copying from * @nr_items: the number of items to copy * * Wrapper around memmove_extent_buffer() that does the math to get the * appropriate offsets into the leaf from the item numbers. */ static inline void memmove_leaf_items(const struct extent_buffer *leaf, int dst_item, int src_item, int nr_items) { memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, dst_item), btrfs_item_nr_offset(leaf, src_item), nr_items * sizeof(struct btrfs_item)); } /* * Copy items from @src into @dst at the given @offset. * * @dst: destination leaf for the items * @src: source leaf for the items * @dst_item: the item nr we're copying into * @src_item: the item nr we're copying from * @nr_items: the number of items to copy * * Wrapper around copy_extent_buffer() that does the math to get the * appropriate offsets into the leaf from the item numbers. */ static inline void copy_leaf_items(const struct extent_buffer *dst, const struct extent_buffer *src, int dst_item, int src_item, int nr_items) { copy_extent_buffer(dst, src, btrfs_item_nr_offset(dst, dst_item), btrfs_item_nr_offset(src, src_item), nr_items * sizeof(struct btrfs_item)); } int btrfs_super_csum_size(const struct btrfs_super_block *sb) { const u16 csum_type = btrfs_super_csum_type(sb); /* csum type is validated at mount time */ return btrfs_csums[csum_type].size; } const char *btrfs_super_csum_name(u16 csum_type) { /* csum type is validated at mount time */ return btrfs_csums[csum_type].name; } /* * Return driver name if defined, otherwise the name that's also a valid driver * name */ const char *btrfs_super_csum_driver(u16 csum_type) { /* csum type is validated at mount time */ return btrfs_csums[csum_type].driver[0] ? btrfs_csums[csum_type].driver : btrfs_csums[csum_type].name; } size_t __attribute_const__ btrfs_get_num_csums(void) { return ARRAY_SIZE(btrfs_csums); } u16 btrfs_csum_type_size(u16 csum_type) { return btrfs_csums[csum_type].size; } struct btrfs_path *btrfs_alloc_path(void) { might_sleep(); return kzalloc(sizeof(struct btrfs_path), GFP_NOFS); } /* this also releases the path */ void btrfs_free_path(struct btrfs_path *p) { if (!p) return; btrfs_release_path(p); kfree(p); } /* * path release drops references on the extent buffers in the path * and it drops any locks held by this path * * It is safe to call this on paths that no locks or extent buffers held. */ noinline void btrfs_release_path(struct btrfs_path *p) { int i; for (i = 0; i < BTRFS_MAX_LEVEL; i++) { p->slots[i] = 0; if (!p->nodes[i]) continue; if (p->locks[i]) { btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]); p->locks[i] = 0; } free_extent_buffer(p->nodes[i]); p->nodes[i] = NULL; } memset(p, 0, sizeof(*p)); } /* * We want the transaction abort to print stack trace only for errors where the * cause could be a bug, eg. due to ENOSPC, and not for common errors that are * caused by external factors. */ bool __cold abort_should_print_stack(int errno) { switch (errno) { case -EIO: case -EROFS: case -ENOMEM: return false; } return true; } void add_root_to_dirty_list(struct btrfs_root *root) { if (test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state) && list_empty(&root->dirty_list)) { list_add(&root->dirty_list, &root->fs_info->dirty_cowonly_roots); } } static void root_add_used(struct btrfs_root *root, u32 size) { btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) + size); } static void root_sub_used(struct btrfs_root *root, u32 size) { btrfs_set_root_used(&root->root_item, btrfs_root_used(&root->root_item) - size); } 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(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != root->fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && 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_tree_block(trans, new_root, 0, new_root_objectid, &disk_key, level, buf->start, 0, BTRFS_NESTING_NORMAL); if (IS_ERR(cow)) { kfree(new_root); return PTR_ERR(cow); } copy_extent_buffer_full(cow, buf); 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_fsid(cow, root->fs_info->fs_devices->metadata_uuid); 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; } /* * Create a new tree root, with root objectid set to @objectid. * * NOTE: Doesn't support tree with non-zero offset, like data reloc tree. */ int btrfs_create_root(struct btrfs_trans_handle *trans, struct btrfs_fs_info *fs_info, u64 objectid) { struct extent_buffer *node; struct btrfs_root *new_root; struct btrfs_disk_key disk_key; struct btrfs_key location; struct btrfs_root_item root_item = { 0 }; int ret; new_root = kmalloc(sizeof(*new_root), GFP_KERNEL); if (!new_root) return -ENOMEM; btrfs_setup_root(new_root, fs_info, objectid); if (!is_fstree(objectid)) set_bit(BTRFS_ROOT_TRACK_DIRTY, &new_root->state); add_root_to_dirty_list(new_root); new_root->objectid = objectid; new_root->root_key.objectid = objectid; new_root->root_key.type = BTRFS_ROOT_ITEM_KEY; new_root->root_key.offset = 0; node = btrfs_alloc_tree_block(trans, new_root, fs_info->nodesize, objectid, &disk_key, 0, 0, 0, BTRFS_NESTING_NORMAL); if (IS_ERR(node)) { ret = PTR_ERR(node); error("failed to create root node for tree %llu: %d (%m)", objectid, ret); return ret; } new_root->node = node; memset_extent_buffer(node, 0, 0, sizeof(struct btrfs_header)); btrfs_set_header_bytenr(node, node->start); btrfs_set_header_generation(node, trans->transid); btrfs_set_header_backref_rev(node, BTRFS_MIXED_BACKREF_REV); btrfs_set_header_owner(node, objectid); write_extent_buffer_fsid(node, fs_info->fs_devices->metadata_uuid); write_extent_buffer_chunk_tree_uuid(node, fs_info->chunk_tree_uuid); btrfs_set_header_nritems(node, 0); btrfs_set_header_level(node, 0); ret = btrfs_inc_ref(trans, new_root, node, 0); if (ret < 0) goto free; /* * Special tree roots may need to modify pointers in @fs_info * Only quota is supported yet. */ switch (objectid) { case BTRFS_QUOTA_TREE_OBJECTID: if (fs_info->quota_root) { error("quota root already exists"); ret = -EEXIST; goto free; } fs_info->quota_root = new_root; fs_info->quota_enabled = 1; break; case BTRFS_BLOCK_GROUP_TREE_OBJECTID: if (fs_info->block_group_root) { error("bg root already exists"); ret = -EEXIST; goto free; } fs_info->block_group_root = new_root; break; /* * Essential trees can't be created by this function, yet. * As we expect such skeleton exists, or a lot of functions like * btrfs_alloc_tree_block() doesn't work at all */ case BTRFS_ROOT_TREE_OBJECTID: case BTRFS_EXTENT_TREE_OBJECTID: case BTRFS_CHUNK_TREE_OBJECTID: case BTRFS_FS_TREE_OBJECTID: ret = -EEXIST; goto free; default: /* Subvolume trees don't need special handling */ if (is_fstree(objectid)) break; /* Other special trees are not supported yet */ ret = -ENOTTY; goto free; } btrfs_mark_buffer_dirty(node); btrfs_set_root_bytenr(&root_item, btrfs_header_bytenr(node)); btrfs_set_root_level(&root_item, 0); btrfs_set_root_generation(&root_item, trans->transid); btrfs_set_root_dirid(&root_item, 0); btrfs_set_root_refs(&root_item, 1); btrfs_set_root_used(&root_item, fs_info->nodesize); location.objectid = objectid; location.type = BTRFS_ROOT_ITEM_KEY; location.offset = 0; ret = btrfs_insert_root(trans, fs_info->tree_root, &location, &root_item); if (ret < 0) goto free; return ret; free: free_extent_buffer(node); kfree(new_root); return ret; } /* * 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 shareable 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 (test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && 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; 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, trans->fs_info, 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_disk_extent_flags(trans, 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); } btrfs_clear_buffer_dirty(trans, 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 extent_buffer *cow; struct btrfs_disk_key disk_key; int level; WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && trans->transid != root->fs_info->running_transaction->transid); WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && 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_tree_block(trans, root, 0, root->root_key.objectid, &disk_key, level, search_start, empty_size, BTRFS_NESTING_NORMAL); if (IS_ERR(cow)) return PTR_ERR(cow); copy_extent_buffer_full(cow, buf); 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_fsid(cow, root->fs_info->fs_devices->metadata_uuid); WARN_ON(!(buf->flags & EXTENT_BUFFER_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, 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, buf->start, buf->len, 0, root->root_key.objectid, level, 0); } 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, enum btrfs_lock_nesting nest) { u64 search_start; int ret; /* if (trans->transaction != root->fs_info->running_transaction) { printk(KERN_CRIT "trans %llu running %llu\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)SZ_1G - 1); 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 __attribute__((unused)) 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; } /* * same as comp_keys only with two btrfs_key's */ int __pure btrfs_comp_cpu_keys(const struct btrfs_key *k1, const 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, const struct btrfs_key *k2) { struct btrfs_key k1; btrfs_disk_key_to_cpu(&k1, disk); return btrfs_comp_cpu_keys(&k1, k2); } static int noinline check_block(struct btrfs_fs_info *fs_info, struct btrfs_path *path, int level) { enum btrfs_tree_block_status ret; if (path->skip_check_block) return 0; if (level == 0) ret = __btrfs_check_leaf(path->nodes[0]); else ret = __btrfs_check_node(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, const 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 */ int btrfs_bin_search(struct extent_buffer *eb, int first_slot, const struct btrfs_key *key, int *slot) { if (btrfs_header_level(eb) == 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 *btrfs_read_node_slot(struct extent_buffer *parent, int slot) { struct btrfs_fs_info *fs_info = parent->fs_info; struct extent_buffer *ret; struct btrfs_tree_parent_check check = { 0 }; int level = btrfs_header_level(parent); if (slot < 0) return NULL; if (slot >= btrfs_header_nritems(parent)) return NULL; if (level == 0) return NULL; check.owner_root = btrfs_header_owner(parent); check.transid = btrfs_node_ptr_generation(parent, slot); check.level = level - 1; ret = read_tree_block(fs_info, btrfs_node_blockptr(parent, slot), &check); if (!extent_buffer_uptodate(ret)) return ERR_PTR(-EIO); if (btrfs_header_level(ret) != level - 1) { error( "child eb corrupted: parent bytenr=%llu item=%d parent level=%d child bytenr=%llu child level=%d", btrfs_header_bytenr(parent), slot, btrfs_header_level(parent), btrfs_header_bytenr(ret), btrfs_header_level(ret)); free_extent_buffer(ret); return ERR_PTR(-EIO); } return ret; } /* * 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 btrfs_fs_info *fs_info = root->fs_info; 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 = btrfs_read_node_slot(mid, 0); BUG_ON(!extent_buffer_uptodate(child)); ret = btrfs_cow_block(trans, root, child, mid, 0, &child, BTRFS_NESTING_NORMAL); BUG_ON(ret); root->node = child; add_root_to_dirty_list(root); path->nodes[level] = NULL; btrfs_clear_buffer_dirty(trans, mid); /* once for the path */ free_extent_buffer(mid); root_sub_used(root, mid->len); ret = btrfs_free_extent(trans, mid->start, mid->len, 0, root->root_key.objectid, level, 0); /* once for the root ptr */ free_extent_buffer(mid); return ret; } if (btrfs_header_nritems(mid) > BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4) return 0; left = btrfs_read_node_slot(parent, pslot - 1); if (extent_buffer_uptodate(left)) { wret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, BTRFS_NESTING_NORMAL); if (wret) { ret = wret; goto enospc; } } right = btrfs_read_node_slot(parent, pslot + 1); if (extent_buffer_uptodate(right)) { wret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, BTRFS_NESTING_NORMAL); 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, 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, mid, right, 1); if (wret < 0 && wret != -ENOSPC) ret = wret; if (btrfs_header_nritems(right) == 0) { u64 bytenr = right->start; u32 blocksize = right->len; btrfs_clear_buffer_dirty(trans, right); free_extent_buffer(right); right = NULL; btrfs_del_ptr(trans, root, path, level + 1, pslot + 1); root_sub_used(root, blocksize); wret = btrfs_free_extent(trans, 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, mid, left); if (wret < 0) { ret = wret; goto enospc; } if (wret == 1) { wret = push_node_left(trans, 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; btrfs_clear_buffer_dirty(trans, mid); free_extent_buffer(mid); mid = NULL; btrfs_del_ptr(trans, root, path, level + 1, pslot); root_sub_used(root, blocksize); wret = btrfs_free_extent(trans, 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->fs_info, 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; } /* 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 btrfs_fs_info *fs_info = root->fs_info; 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 = btrfs_read_node_slot(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(fs_info) - 1) { wret = 1; } else { ret = btrfs_cow_block(trans, root, left, parent, pslot - 1, &left, BTRFS_NESTING_NORMAL); if (ret) wret = 1; else { wret = push_node_left(trans, 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= btrfs_read_node_slot(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->fs_info) - 1) { wret = 1; } else { ret = btrfs_cow_block(trans, root, right, parent, pslot + 1, &right, BTRFS_NESTING_NORMAL); if (ret) wret = 1; else { wret = balance_node_right(trans, 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, finding things that are close * to the block in 'slot', and triggering ra on them. */ static void reada_for_search(struct btrfs_fs_info *fs_info, 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 nscan = 0; if (level != 1) return; if (!path->nodes[level]) return; node = path->nodes[level]; search = btrfs_node_blockptr(node, slot); eb = btrfs_find_tree_block(fs_info, search, fs_info->nodesize); 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(fs_info, search, btrfs_node_ptr_generation(node, nr)); nread += fs_info->nodesize; } nscan++; if (path->reada < 2 && (nread > SZ_256K || nscan > 32)) break; if(nread > SZ_1M || 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, const 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; struct btrfs_fs_info *fs_info = root->fs_info; u8 lowest_level = 0; lowest_level = p->lowest_level; WARN_ON(lowest_level && ins_len > 0); WARN_ON(p->nodes[0] != NULL); 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, BTRFS_NESTING_NORMAL); 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(fs_info, p, level); if (ret) return -1; ret = btrfs_bin_search(b, 0, key, &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(fs_info) - 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(fs_info, p, level, slot, key->objectid); b = btrfs_read_node_slot(b, slot); if (!extent_buffer_uptodate(b)) return -EIO; } else { p->slots[level] = slot; if (ins_len > 0 && ins_len > btrfs_leaf_free_space(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; } /* * Helper to use instead of search slot if no exact match is needed but * instead the next or previous item should be returned. * When find_higher is true, the next higher item is returned, the next lower * otherwise. * When return_any and find_higher are both true, and no higher item is found, * return the next lower instead. * When return_any is true and find_higher is false, and no lower item is found, * return the next higher instead. * It returns 0 if any item is found, 1 if none is found (tree empty), and * < 0 on error */ int btrfs_search_slot_for_read(struct btrfs_root *root, const struct btrfs_key *key, struct btrfs_path *p, int find_higher, int return_any) { int ret; struct extent_buffer *leaf; again: ret = btrfs_search_slot(NULL, root, key, p, 0, 0); if (ret <= 0) return ret; /* * A return value of 1 means the path is at the position where the item * should be inserted. Normally this is the next bigger item, but in * case the previous item is the last in a leaf, path points to the * first free slot in the previous leaf, i.e. at an invalid item. */ leaf = p->nodes[0]; if (find_higher) { if (p->slots[0] >= btrfs_header_nritems(leaf)) { ret = btrfs_next_leaf(root, p); if (ret <= 0) return ret; if (!return_any) return 1; /* * No higher item found, return the next lower instead */ return_any = 0; find_higher = 0; btrfs_release_path(p); goto again; } } else { if (p->slots[0] == 0) { ret = btrfs_prev_leaf(root, p); if (ret < 0) return ret; if (!ret) { leaf = p->nodes[0]; if (p->slots[0] == btrfs_header_nritems(leaf)) p->slots[0]--; return 0; } if (!return_any) return 1; /* * No lower item found, return the next higher instead */ return_any = 0; find_higher = 1; btrfs_release_path(p); goto again; } else { --p->slots[0]; } } return 0; } /* * adjust the pointers going up the tree, starting at level * making sure the right key of each node is points to 'key'. * This is used after shifting pointers to the left, so it stops * fixing up pointers when a given leaf/node is not in slot 0 of the * higher levels */ static void fixup_low_keys(struct btrfs_path *path, struct btrfs_disk_key *key, int level) { int i; struct extent_buffer *t; for (i = level; i < BTRFS_MAX_LEVEL; i++) { int tslot = path->slots[i]; if (!path->nodes[i]) break; t = path->nodes[i]; btrfs_set_node_key(t, key, tslot); btrfs_mark_buffer_dirty(path->nodes[i]); if (tslot != 0) break; } } /* * update item key. * * This function isn't completely safe. It's the caller's responsibility * that the new key won't break the order */ void btrfs_set_item_key_safe(struct btrfs_fs_info *fs_info, struct btrfs_path *path, const struct btrfs_key *new_key) { struct btrfs_disk_key disk_key; struct extent_buffer *eb; int slot; eb = path->nodes[0]; slot = path->slots[0]; if (slot > 0) { btrfs_item_key(eb, &disk_key, slot - 1); BUG_ON(btrfs_comp_keys(&disk_key, new_key) >= 0); } if (slot < btrfs_header_nritems(eb) - 1) { btrfs_item_key(eb, &disk_key, slot + 1); BUG_ON(btrfs_comp_keys(&disk_key, new_key) <= 0); } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(eb, &disk_key, slot); btrfs_mark_buffer_dirty(eb); if (slot == 0) fixup_low_keys(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 extent_buffer *dst, struct extent_buffer *src, int empty) { struct btrfs_fs_info *fs_info = trans->fs_info; 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(fs_info) - 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, dst_nritems), btrfs_node_key_ptr_offset(src, 0), push_items * sizeof(struct btrfs_key_ptr)); if (push_items < src_nritems) { memmove_extent_buffer(src, btrfs_node_key_ptr_offset(src, 0), btrfs_node_key_ptr_offset(src, 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 extent_buffer *dst, struct extent_buffer *src) { struct btrfs_fs_info *fs_info = trans->fs_info; 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(fs_info) - 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(dst, push_items), btrfs_node_key_ptr_offset(dst, 0), (dst_nritems) * sizeof(struct btrfs_key_ptr)); copy_extent_buffer(dst, src, btrfs_node_key_ptr_offset(dst, 0), btrfs_node_key_ptr_offset(src, 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_tree_block(trans, root, 0, root->root_key.objectid, &lower_key, level, root->node->start, 0, BTRFS_NESTING_NORMAL); 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); root_add_used(root, root->fs_info->nodesize); write_extent_buffer_fsid(c, root->fs_info->fs_devices->metadata_uuid); write_extent_buffer_chunk_tree_uuid(c, root->fs_info->chunk_tree_uuid); 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->fs_info)) BUG(); if (slot < nritems) { /* shift the items */ memmove_extent_buffer(lower, btrfs_node_key_ptr_offset(lower, slot + 1), btrfs_node_key_ptr_offset(lower, 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->fs_info) - 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_tree_block(trans, root, 0, root->root_key.objectid, &disk_key, level, c->start, 0, BTRFS_NESTING_NORMAL); 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_fsid(split, root->fs_info->fs_devices->metadata_uuid); write_extent_buffer_chunk_tree_uuid(split, root->fs_info->chunk_tree_uuid); root_add_used(root, root->fs_info->nodesize); copy_extent_buffer(split, c, btrfs_node_key_ptr_offset(split, 0), btrfs_node_key_ptr_offset(c, 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(const 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_data_end(l, start); data_len = data_len - btrfs_item_offset(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(const struct extent_buffer *leaf) { int nritems = btrfs_header_nritems(leaf); u32 leaf_data_size; int ret; BUG_ON(!leaf->fs_info); BUG_ON(leaf->fs_info->nodesize != leaf->len); leaf_data_size = BTRFS_LEAF_DATA_SIZE(leaf->fs_info); ret = leaf_data_size - 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, leaf_data_size, 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; 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 = btrfs_read_node_slot(upper, slot + 1); if (!extent_buffer_uptodate(right)) { if (IS_ERR(right)) return PTR_ERR(right); return -EIO; } free_space = btrfs_leaf_free_space(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, BTRFS_NESTING_NORMAL); if (ret) { free_extent_buffer(right); return 1; } free_space = btrfs_leaf_free_space(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) { if (path->slots[0] == i) push_space += data_size + sizeof(struct btrfs_item); this_item_size = btrfs_item_size(left, i); if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(struct btrfs_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_data_end(left, left_nritems - push_items); push_space -= leaf_data_end(left); /* make room in the right data area */ data_end = leaf_data_end(right); memmove_extent_buffer(right, btrfs_item_nr_offset(right, 0) + data_end - push_space, btrfs_item_nr_offset(right, 0) + data_end, BTRFS_LEAF_DATA_SIZE(root->fs_info) - data_end); /* copy from the left data area */ copy_extent_buffer(right, left, btrfs_item_nr_offset(right, 0) + BTRFS_LEAF_DATA_SIZE(root->fs_info) - push_space, btrfs_item_nr_offset(left, 0) + leaf_data_end(left), push_space); memmove_extent_buffer(right, btrfs_item_nr_offset(right, push_items), btrfs_item_nr_offset(right, 0), right_nritems * sizeof(struct btrfs_item)); /* copy the items from left to right */ copy_extent_buffer(right, left, btrfs_item_nr_offset(right, 0), btrfs_item_nr_offset(left, 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->fs_info); for (i = 0; i < right_nritems; i++) { push_space -= btrfs_item_size(right, i); btrfs_set_item_offset(right, i, 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; 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 = btrfs_read_node_slot(path->nodes[1], slot - 1); free_space = btrfs_leaf_free_space(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, BTRFS_NESTING_NORMAL); if (ret) { /* we hit -ENOSPC, but it isn't fatal here */ free_extent_buffer(left); return 1; } free_space = btrfs_leaf_free_space(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++) { if (path->slots[0] == i) push_space += data_size + sizeof(struct btrfs_item); this_item_size = btrfs_item_size(right, i); if (this_item_size + sizeof(struct btrfs_item) + push_space > free_space) break; push_items++; push_space += this_item_size + sizeof(struct btrfs_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(left, btrfs_header_nritems(left)), btrfs_item_nr_offset(right, 0), push_items * sizeof(struct btrfs_item)); push_space = BTRFS_LEAF_DATA_SIZE(root->fs_info) - btrfs_item_offset(right, push_items -1); copy_extent_buffer(left, right, btrfs_item_nr_offset(left, 0) + leaf_data_end(left) - push_space, btrfs_item_nr_offset(right, 0) + btrfs_item_offset(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(left, old_left_nritems - 1); for (i = old_left_nritems; i < old_left_nritems + push_items; i++) { u32 ioff; ioff = btrfs_item_offset(left, i); btrfs_set_item_offset(left, i, ioff - (BTRFS_LEAF_DATA_SIZE(root->fs_info) - 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(right, push_items - 1) - leaf_data_end(right); memmove_extent_buffer(right, btrfs_item_nr_offset(right, 0) + BTRFS_LEAF_DATA_SIZE(root->fs_info) - push_space, btrfs_item_nr_offset(right, 0) + leaf_data_end(right), push_space); memmove_extent_buffer(right, btrfs_item_nr_offset(right, 0), btrfs_item_nr_offset(right, 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->fs_info); for (i = 0; i < right_nritems; i++) { push_space = push_space - btrfs_item_size(right, i); btrfs_set_item_offset(right, i, push_space); } btrfs_mark_buffer_dirty(left); if (right_nritems) btrfs_mark_buffer_dirty(right); btrfs_item_key(right, &disk_key, 0); fixup_low_keys(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_data_end(l, mid) - leaf_data_end(l); copy_extent_buffer(right, l, btrfs_item_nr_offset(right, 0), btrfs_item_nr_offset(l, mid), nritems * sizeof(struct btrfs_item)); copy_extent_buffer(right, l, btrfs_item_nr_offset(right, 0) + BTRFS_LEAF_DATA_SIZE(root->fs_info) - data_copy_size, btrfs_item_nr_offset(l, 0) + leaf_data_end(l), data_copy_size); rt_data_off = BTRFS_LEAF_DATA_SIZE(root->fs_info) - btrfs_item_data_end(l, mid); for (i = 0; i < nritems; i++) { u32 ioff = btrfs_item_offset(right, i); btrfs_set_item_offset(right, i, 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, const 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(l, slot) + sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(root->fs_info)) 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(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->fs_info)) { 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->fs_info)) { split = 2; } } } } else { if (leaf_space_used(l, 0, mid) + data_size > BTRFS_LEAF_DATA_SIZE(root->fs_info)) { 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->fs_info)) { 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_tree_block(trans, root, 0, root->root_key.objectid, &disk_key, 0, l->start, 0, BTRFS_NESTING_NORMAL); 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_fsid(right, root->fs_info->fs_devices->metadata_uuid); write_extent_buffer_chunk_tree_uuid(right, root->fs_info->chunk_tree_uuid); root_add_used(root, root->fs_info->nodesize); 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) fixup_low_keys(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, const struct btrfs_key *new_key, unsigned long split_offset) { u32 item_size; struct extent_buffer *leaf; struct btrfs_key orig_key; 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(leaf) >= sizeof(struct btrfs_item)) goto split; item_size = btrfs_item_size(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(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(leaf) < sizeof(struct btrfs_item)); leaf = path->nodes[0]; split: orig_offset = btrfs_item_offset(leaf, path->slots[0]); item_size = btrfs_item_size(leaf, path->slots[0]); 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(leaf, slot + 1), btrfs_item_nr_offset(leaf, slot), (nritems - slot) * sizeof(struct btrfs_item)); } btrfs_cpu_key_to_disk(&disk_key, new_key); btrfs_set_item_key(leaf, &disk_key, slot); btrfs_set_item_offset(leaf, slot, orig_offset); btrfs_set_item_size(leaf, slot, item_size - split_offset); btrfs_set_item_offset(leaf, path->slots[0], orig_offset + item_size - split_offset); btrfs_set_item_size(leaf, path->slots[0], 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(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } kfree(buf); return ret; } void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end) { int slot; struct extent_buffer *leaf; 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(leaf, slot); if (old_size == new_size) return; nritems = btrfs_header_nritems(leaf); data_end = leaf_data_end(leaf); old_data_start = btrfs_item_offset(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; ioff = btrfs_item_offset(leaf, i); btrfs_set_item_offset(leaf, i, ioff + size_diff); } /* shift the data */ if (from_end) { memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + data_end + size_diff, btrfs_item_nr_offset(leaf, 0) + 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_item_nr_offset(leaf, 0) + data_end + size_diff, btrfs_item_nr_offset(leaf, 0) + data_end, old_data_start - data_end); offset = btrfs_disk_key_offset(&disk_key); btrfs_set_disk_key_offset(&disk_key, offset + size_diff); btrfs_set_item_key(leaf, &disk_key, slot); if (slot == 0) fixup_low_keys(path, &disk_key, 1); } btrfs_set_item_size(leaf, slot, new_size); btrfs_mark_buffer_dirty(leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } void btrfs_extend_item(struct btrfs_path *path, u32 data_size) { int slot; struct extent_buffer *leaf; 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(leaf); if (btrfs_leaf_free_space(leaf) < data_size) { btrfs_print_leaf(leaf); BUG(); } slot = path->slots[0]; old_data = btrfs_item_data_end(leaf, slot); BUG_ON(slot < 0); if (slot >= nritems) { btrfs_print_leaf(leaf); printk("slot %d too large, nritems %u\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; ioff = btrfs_item_offset(leaf, i); btrfs_set_item_offset(leaf, i, ioff - data_size); } /* shift the data */ memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + data_end - data_size, btrfs_item_nr_offset(leaf, 0) + data_end, old_data - data_end); data_end = old_data; old_size = btrfs_item_size(leaf, slot); btrfs_set_item_size(leaf, slot, old_size + data_size); btrfs_mark_buffer_dirty(leaf); if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(leaf); BUG(); } } /* * 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, const struct btrfs_item_batch *batch) { struct extent_buffer *leaf; int ret = 0; int slot; int i; u32 nritems; u32 total_size = 0; unsigned int data_end; struct btrfs_disk_key disk_key; /* create a root if there isn't one */ if (!root->node) BUG(); total_size = batch->total_data_size + (batch->nr * sizeof(struct btrfs_item)); ret = btrfs_search_slot(trans, root, &batch->keys[0], 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(leaf); if (btrfs_leaf_free_space(leaf) < total_size) { btrfs_print_leaf(leaf); printk("not enough freespace need %u have %d\n", total_size, btrfs_leaf_free_space(leaf)); BUG(); } slot = path->slots[0]; BUG_ON(slot < 0); if (slot < nritems) { unsigned int old_data = btrfs_item_data_end(leaf, slot); if (old_data < data_end) { btrfs_print_leaf(leaf); printk("slot %d old_data %u data_end %u\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; ioff = btrfs_item_offset(leaf, i); btrfs_set_item_offset(leaf, i, ioff - batch->total_data_size); } /* shift the items */ memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, slot + batch->nr), btrfs_item_nr_offset(leaf, slot), (nritems - slot) * sizeof(struct btrfs_item)); /* shift the data */ memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + data_end - batch->total_data_size, btrfs_item_nr_offset(leaf, 0) + data_end, old_data - data_end); data_end = old_data; } /* setup the item for the new data */ for (i = 0; i < batch->nr; i++) { btrfs_cpu_key_to_disk(&disk_key, &batch->keys[i]); btrfs_set_item_key(leaf, &disk_key, slot + i); data_end -= batch->data_sizes[i]; btrfs_set_item_offset(leaf, slot + i, data_end); btrfs_set_item_size(leaf, slot + i, batch->data_sizes[i]); } btrfs_set_header_nritems(leaf, nritems + batch->nr); btrfs_mark_buffer_dirty(leaf); ret = 0; if (slot == 0) { btrfs_cpu_key_to_disk(&disk_key, &batch->keys[0]); fixup_low_keys(path, &disk_key, 1); } if (btrfs_leaf_free_space(leaf) < 0) { btrfs_print_leaf(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, const struct btrfs_key *cpu_key, void *data, u32 data_size) { int ret = 0; struct btrfs_path *path; struct extent_buffer *leaf; unsigned long ptr; path = btrfs_alloc_path(); if (!path) return -ENOMEM; ret = btrfs_insert_empty_item(trans, root, path, cpu_key, data_size); if (!ret) { leaf = path->nodes[0]; ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); write_extent_buffer(leaf, data, ptr, data_size); btrfs_mark_buffer_dirty(leaf); } btrfs_free_path(path); return ret; } /* * delete the pointer from a given node. * * 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; nritems = btrfs_header_nritems(parent); if (slot < nritems - 1) { /* shift the items */ memmove_extent_buffer(parent, btrfs_node_key_ptr_offset(parent, slot), btrfs_node_key_ptr_offset(parent, slot + 1), sizeof(struct btrfs_key_ptr) * (nritems - slot - 1)); } nritems--; btrfs_set_header_nritems(parent, nritems); if (nritems == 0 && parent == root->node) { BUG_ON(btrfs_header_level(root->node) != 1); /* just turn the root into a leaf and break */ btrfs_set_header_level(root->node, 0); } else if (slot == 0) { struct btrfs_disk_key disk_key; btrfs_node_key(parent, &disk_key, 0); fixup_low_keys(path, &disk_key, level + 1); } btrfs_mark_buffer_dirty(parent); return 0; } /* * 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); btrfs_del_ptr(trans, root, path, 1, path->slots[1]); root_sub_used(root, leaf->len); ret = btrfs_free_extent(trans, 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; int last_off; int dsize = 0; int ret = 0; int wret; int i; u32 nritems; leaf = path->nodes[0]; last_off = btrfs_item_offset(leaf, slot + nr - 1); for (i = 0; i < nr; i++) dsize += btrfs_item_size(leaf, slot + i); nritems = btrfs_header_nritems(leaf); if (slot + nr != nritems) { int data_end = leaf_data_end(leaf); memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, 0) + data_end + dsize, btrfs_item_nr_offset(leaf, 0) + data_end, last_off - data_end); for (i = slot + nr; i < nritems; i++) { u32 ioff; ioff = btrfs_item_offset(leaf, i); btrfs_set_item_offset(leaf, i, ioff + dsize); } memmove_extent_buffer(leaf, btrfs_item_nr_offset(leaf, slot), btrfs_item_nr_offset(leaf, slot + nr), sizeof(struct btrfs_item) * (nritems - slot - nr)); } btrfs_set_header_nritems(leaf, nritems - nr); nritems -= nr; /* delete the leaf if we've emptied it */ if (nritems == 0) { if (leaf == root->node) { btrfs_set_header_level(leaf, 0); } else { btrfs_clear_buffer_dirty(trans, 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); fixup_low_keys(path, &disk_key, 1); } /* delete the leaf if it is mostly empty */ if (used < BTRFS_LEAF_DATA_SIZE(root->fs_info) / 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) { btrfs_clear_buffer_dirty(trans, 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 = btrfs_read_node_slot(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 = btrfs_read_node_slot(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 necessary to find the next sibling tree block. * More generic version of btrfs_next_leaf(), as it could find sibling nodes * if @path->lowest_level is not 0. * * returns 0 if it found something or 1 if there are no greater leaves. * returns < 0 on io errors. */ int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info, struct btrfs_path *path) { int slot; int level = path->lowest_level + 1; struct extent_buffer *c; struct extent_buffer *next = NULL; BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL); do { 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(fs_info, path, level, slot, 0); next = btrfs_read_node_slot(c, slot); if (!extent_buffer_uptodate(next)) return -EIO; break; } while (level < BTRFS_MAX_LEVEL); path->slots[level] = slot; while(1) { level--; c = path->nodes[level]; free_extent_buffer(c); path->nodes[level] = next; path->slots[level] = 0; /* * Fsck will happily load corrupt blocks in order to fix them, * so we need an extra check just to make sure this block isn't * marked uptodate but invalid. */ if (check_block(fs_info, path, level)) return -EIO; if (level == path->lowest_level) break; if (path->reada) reada_for_search(fs_info, path, level, 0, 0); next = btrfs_read_node_slot(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; 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 == type) return 0; if (found_key.objectid == min_objectid && found_key.type < type) break; } return 1; } /* * search in extent tree to find a previous Metadata/Data extent item with * min objectid. * * 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; }