| /* |
| * Copyright (C) 2011 STRATO. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public |
| * License v2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public |
| * License along with this program; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 021110-1307, USA. |
| */ |
| |
| #include <linux/vmalloc.h> |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "backref.h" |
| #include "ulist.h" |
| #include "transaction.h" |
| #include "delayed-ref.h" |
| #include "locking.h" |
| |
| struct extent_inode_elem { |
| u64 inum; |
| u64 offset; |
| struct extent_inode_elem *next; |
| }; |
| |
| static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb, |
| struct btrfs_file_extent_item *fi, |
| u64 extent_item_pos, |
| struct extent_inode_elem **eie) |
| { |
| u64 offset = 0; |
| struct extent_inode_elem *e; |
| |
| if (!btrfs_file_extent_compression(eb, fi) && |
| !btrfs_file_extent_encryption(eb, fi) && |
| !btrfs_file_extent_other_encoding(eb, fi)) { |
| u64 data_offset; |
| u64 data_len; |
| |
| data_offset = btrfs_file_extent_offset(eb, fi); |
| data_len = btrfs_file_extent_num_bytes(eb, fi); |
| |
| if (extent_item_pos < data_offset || |
| extent_item_pos >= data_offset + data_len) |
| return 1; |
| offset = extent_item_pos - data_offset; |
| } |
| |
| e = kmalloc(sizeof(*e), GFP_NOFS); |
| if (!e) |
| return -ENOMEM; |
| |
| e->next = *eie; |
| e->inum = key->objectid; |
| e->offset = key->offset + offset; |
| *eie = e; |
| |
| return 0; |
| } |
| |
| static int find_extent_in_eb(struct extent_buffer *eb, u64 wanted_disk_byte, |
| u64 extent_item_pos, |
| struct extent_inode_elem **eie) |
| { |
| u64 disk_byte; |
| struct btrfs_key key; |
| struct btrfs_file_extent_item *fi; |
| int slot; |
| int nritems; |
| int extent_type; |
| int ret; |
| |
| /* |
| * from the shared data ref, we only have the leaf but we need |
| * the key. thus, we must look into all items and see that we |
| * find one (some) with a reference to our extent item. |
| */ |
| nritems = btrfs_header_nritems(eb); |
| for (slot = 0; slot < nritems; ++slot) { |
| btrfs_item_key_to_cpu(eb, &key, slot); |
| if (key.type != BTRFS_EXTENT_DATA_KEY) |
| continue; |
| fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); |
| extent_type = btrfs_file_extent_type(eb, fi); |
| if (extent_type == BTRFS_FILE_EXTENT_INLINE) |
| continue; |
| /* don't skip BTRFS_FILE_EXTENT_PREALLOC, we can handle that */ |
| disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
| if (disk_byte != wanted_disk_byte) |
| continue; |
| |
| ret = check_extent_in_eb(&key, eb, fi, extent_item_pos, eie); |
| if (ret < 0) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * this structure records all encountered refs on the way up to the root |
| */ |
| struct __prelim_ref { |
| struct list_head list; |
| u64 root_id; |
| struct btrfs_key key_for_search; |
| int level; |
| int count; |
| struct extent_inode_elem *inode_list; |
| u64 parent; |
| u64 wanted_disk_byte; |
| }; |
| |
| static struct kmem_cache *btrfs_prelim_ref_cache; |
| |
| int __init btrfs_prelim_ref_init(void) |
| { |
| btrfs_prelim_ref_cache = kmem_cache_create("btrfs_prelim_ref", |
| sizeof(struct __prelim_ref), |
| 0, |
| SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, |
| NULL); |
| if (!btrfs_prelim_ref_cache) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| void btrfs_prelim_ref_exit(void) |
| { |
| if (btrfs_prelim_ref_cache) |
| kmem_cache_destroy(btrfs_prelim_ref_cache); |
| } |
| |
| /* |
| * the rules for all callers of this function are: |
| * - obtaining the parent is the goal |
| * - if you add a key, you must know that it is a correct key |
| * - if you cannot add the parent or a correct key, then we will look into the |
| * block later to set a correct key |
| * |
| * delayed refs |
| * ============ |
| * backref type | shared | indirect | shared | indirect |
| * information | tree | tree | data | data |
| * --------------------+--------+----------+--------+---------- |
| * parent logical | y | - | - | - |
| * key to resolve | - | y | y | y |
| * tree block logical | - | - | - | - |
| * root for resolving | y | y | y | y |
| * |
| * - column 1: we've the parent -> done |
| * - column 2, 3, 4: we use the key to find the parent |
| * |
| * on disk refs (inline or keyed) |
| * ============================== |
| * backref type | shared | indirect | shared | indirect |
| * information | tree | tree | data | data |
| * --------------------+--------+----------+--------+---------- |
| * parent logical | y | - | y | - |
| * key to resolve | - | - | - | y |
| * tree block logical | y | y | y | y |
| * root for resolving | - | y | y | y |
| * |
| * - column 1, 3: we've the parent -> done |
| * - column 2: we take the first key from the block to find the parent |
| * (see __add_missing_keys) |
| * - column 4: we use the key to find the parent |
| * |
| * additional information that's available but not required to find the parent |
| * block might help in merging entries to gain some speed. |
| */ |
| |
| static int __add_prelim_ref(struct list_head *head, u64 root_id, |
| struct btrfs_key *key, int level, |
| u64 parent, u64 wanted_disk_byte, int count, |
| gfp_t gfp_mask) |
| { |
| struct __prelim_ref *ref; |
| |
| if (root_id == BTRFS_DATA_RELOC_TREE_OBJECTID) |
| return 0; |
| |
| ref = kmem_cache_alloc(btrfs_prelim_ref_cache, gfp_mask); |
| if (!ref) |
| return -ENOMEM; |
| |
| ref->root_id = root_id; |
| if (key) |
| ref->key_for_search = *key; |
| else |
| memset(&ref->key_for_search, 0, sizeof(ref->key_for_search)); |
| |
| ref->inode_list = NULL; |
| ref->level = level; |
| ref->count = count; |
| ref->parent = parent; |
| ref->wanted_disk_byte = wanted_disk_byte; |
| list_add_tail(&ref->list, head); |
| |
| return 0; |
| } |
| |
| static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path, |
| struct ulist *parents, struct __prelim_ref *ref, |
| int level, u64 time_seq, const u64 *extent_item_pos) |
| { |
| int ret = 0; |
| int slot; |
| struct extent_buffer *eb; |
| struct btrfs_key key; |
| struct btrfs_key *key_for_search = &ref->key_for_search; |
| struct btrfs_file_extent_item *fi; |
| struct extent_inode_elem *eie = NULL, *old = NULL; |
| u64 disk_byte; |
| u64 wanted_disk_byte = ref->wanted_disk_byte; |
| u64 count = 0; |
| |
| if (level != 0) { |
| eb = path->nodes[level]; |
| ret = ulist_add(parents, eb->start, 0, GFP_NOFS); |
| if (ret < 0) |
| return ret; |
| return 0; |
| } |
| |
| /* |
| * We normally enter this function with the path already pointing to |
| * the first item to check. But sometimes, we may enter it with |
| * slot==nritems. In that case, go to the next leaf before we continue. |
| */ |
| if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) |
| ret = btrfs_next_old_leaf(root, path, time_seq); |
| |
| while (!ret && count < ref->count) { |
| eb = path->nodes[0]; |
| slot = path->slots[0]; |
| |
| btrfs_item_key_to_cpu(eb, &key, slot); |
| |
| if (key.objectid != key_for_search->objectid || |
| key.type != BTRFS_EXTENT_DATA_KEY) |
| break; |
| |
| fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item); |
| disk_byte = btrfs_file_extent_disk_bytenr(eb, fi); |
| |
| if (disk_byte == wanted_disk_byte) { |
| eie = NULL; |
| old = NULL; |
| count++; |
| if (extent_item_pos) { |
| ret = check_extent_in_eb(&key, eb, fi, |
| *extent_item_pos, |
| &eie); |
| if (ret < 0) |
| break; |
| } |
| if (ret > 0) |
| goto next; |
| ret = ulist_add_merge(parents, eb->start, |
| (uintptr_t)eie, |
| (u64 *)&old, GFP_NOFS); |
| if (ret < 0) |
| break; |
| if (!ret && extent_item_pos) { |
| while (old->next) |
| old = old->next; |
| old->next = eie; |
| } |
| } |
| next: |
| ret = btrfs_next_old_item(root, path, time_seq); |
| } |
| |
| if (ret > 0) |
| ret = 0; |
| return ret; |
| } |
| |
| /* |
| * resolve an indirect backref in the form (root_id, key, level) |
| * to a logical address |
| */ |
| static int __resolve_indirect_ref(struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, u64 time_seq, |
| struct __prelim_ref *ref, |
| struct ulist *parents, |
| const u64 *extent_item_pos) |
| { |
| struct btrfs_root *root; |
| struct btrfs_key root_key; |
| struct extent_buffer *eb; |
| int ret = 0; |
| int root_level; |
| int level = ref->level; |
| int index; |
| |
| root_key.objectid = ref->root_id; |
| root_key.type = BTRFS_ROOT_ITEM_KEY; |
| root_key.offset = (u64)-1; |
| |
| index = srcu_read_lock(&fs_info->subvol_srcu); |
| |
| root = btrfs_read_fs_root_no_name(fs_info, &root_key); |
| if (IS_ERR(root)) { |
| srcu_read_unlock(&fs_info->subvol_srcu, index); |
| ret = PTR_ERR(root); |
| goto out; |
| } |
| |
| root_level = btrfs_old_root_level(root, time_seq); |
| |
| if (root_level + 1 == level) { |
| srcu_read_unlock(&fs_info->subvol_srcu, index); |
| goto out; |
| } |
| |
| path->lowest_level = level; |
| ret = btrfs_search_old_slot(root, &ref->key_for_search, path, time_seq); |
| |
| /* root node has been locked, we can release @subvol_srcu safely here */ |
| srcu_read_unlock(&fs_info->subvol_srcu, index); |
| |
| pr_debug("search slot in root %llu (level %d, ref count %d) returned " |
| "%d for key (%llu %u %llu)\n", |
| ref->root_id, level, ref->count, ret, |
| ref->key_for_search.objectid, ref->key_for_search.type, |
| ref->key_for_search.offset); |
| if (ret < 0) |
| goto out; |
| |
| eb = path->nodes[level]; |
| while (!eb) { |
| if (WARN_ON(!level)) { |
| ret = 1; |
| goto out; |
| } |
| level--; |
| eb = path->nodes[level]; |
| } |
| |
| ret = add_all_parents(root, path, parents, ref, level, time_seq, |
| extent_item_pos); |
| out: |
| path->lowest_level = 0; |
| btrfs_release_path(path); |
| return ret; |
| } |
| |
| /* |
| * resolve all indirect backrefs from the list |
| */ |
| static int __resolve_indirect_refs(struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, u64 time_seq, |
| struct list_head *head, |
| const u64 *extent_item_pos) |
| { |
| int err; |
| int ret = 0; |
| struct __prelim_ref *ref; |
| struct __prelim_ref *ref_safe; |
| struct __prelim_ref *new_ref; |
| struct ulist *parents; |
| struct ulist_node *node; |
| struct ulist_iterator uiter; |
| |
| parents = ulist_alloc(GFP_NOFS); |
| if (!parents) |
| return -ENOMEM; |
| |
| /* |
| * _safe allows us to insert directly after the current item without |
| * iterating over the newly inserted items. |
| * we're also allowed to re-assign ref during iteration. |
| */ |
| list_for_each_entry_safe(ref, ref_safe, head, list) { |
| if (ref->parent) /* already direct */ |
| continue; |
| if (ref->count == 0) |
| continue; |
| err = __resolve_indirect_ref(fs_info, path, time_seq, ref, |
| parents, extent_item_pos); |
| if (err == -ENOMEM) |
| goto out; |
| if (err) |
| continue; |
| |
| /* we put the first parent into the ref at hand */ |
| ULIST_ITER_INIT(&uiter); |
| node = ulist_next(parents, &uiter); |
| ref->parent = node ? node->val : 0; |
| ref->inode_list = node ? |
| (struct extent_inode_elem *)(uintptr_t)node->aux : NULL; |
| |
| /* additional parents require new refs being added here */ |
| while ((node = ulist_next(parents, &uiter))) { |
| new_ref = kmem_cache_alloc(btrfs_prelim_ref_cache, |
| GFP_NOFS); |
| if (!new_ref) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| memcpy(new_ref, ref, sizeof(*ref)); |
| new_ref->parent = node->val; |
| new_ref->inode_list = (struct extent_inode_elem *) |
| (uintptr_t)node->aux; |
| list_add(&new_ref->list, &ref->list); |
| } |
| ulist_reinit(parents); |
| } |
| out: |
| ulist_free(parents); |
| return ret; |
| } |
| |
| static inline int ref_for_same_block(struct __prelim_ref *ref1, |
| struct __prelim_ref *ref2) |
| { |
| if (ref1->level != ref2->level) |
| return 0; |
| if (ref1->root_id != ref2->root_id) |
| return 0; |
| if (ref1->key_for_search.type != ref2->key_for_search.type) |
| return 0; |
| if (ref1->key_for_search.objectid != ref2->key_for_search.objectid) |
| return 0; |
| if (ref1->key_for_search.offset != ref2->key_for_search.offset) |
| return 0; |
| if (ref1->parent != ref2->parent) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* |
| * read tree blocks and add keys where required. |
| */ |
| static int __add_missing_keys(struct btrfs_fs_info *fs_info, |
| struct list_head *head) |
| { |
| struct list_head *pos; |
| struct extent_buffer *eb; |
| |
| list_for_each(pos, head) { |
| struct __prelim_ref *ref; |
| ref = list_entry(pos, struct __prelim_ref, list); |
| |
| if (ref->parent) |
| continue; |
| if (ref->key_for_search.type) |
| continue; |
| BUG_ON(!ref->wanted_disk_byte); |
| eb = read_tree_block(fs_info->tree_root, ref->wanted_disk_byte, |
| fs_info->tree_root->leafsize, 0); |
| if (!eb || !extent_buffer_uptodate(eb)) { |
| free_extent_buffer(eb); |
| return -EIO; |
| } |
| btrfs_tree_read_lock(eb); |
| if (btrfs_header_level(eb) == 0) |
| btrfs_item_key_to_cpu(eb, &ref->key_for_search, 0); |
| else |
| btrfs_node_key_to_cpu(eb, &ref->key_for_search, 0); |
| btrfs_tree_read_unlock(eb); |
| free_extent_buffer(eb); |
| } |
| return 0; |
| } |
| |
| /* |
| * merge two lists of backrefs and adjust counts accordingly |
| * |
| * mode = 1: merge identical keys, if key is set |
| * FIXME: if we add more keys in __add_prelim_ref, we can merge more here. |
| * additionally, we could even add a key range for the blocks we |
| * looked into to merge even more (-> replace unresolved refs by those |
| * having a parent). |
| * mode = 2: merge identical parents |
| */ |
| static void __merge_refs(struct list_head *head, int mode) |
| { |
| struct list_head *pos1; |
| |
| list_for_each(pos1, head) { |
| struct list_head *n2; |
| struct list_head *pos2; |
| struct __prelim_ref *ref1; |
| |
| ref1 = list_entry(pos1, struct __prelim_ref, list); |
| |
| for (pos2 = pos1->next, n2 = pos2->next; pos2 != head; |
| pos2 = n2, n2 = pos2->next) { |
| struct __prelim_ref *ref2; |
| struct __prelim_ref *xchg; |
| struct extent_inode_elem *eie; |
| |
| ref2 = list_entry(pos2, struct __prelim_ref, list); |
| |
| if (mode == 1) { |
| if (!ref_for_same_block(ref1, ref2)) |
| continue; |
| if (!ref1->parent && ref2->parent) { |
| xchg = ref1; |
| ref1 = ref2; |
| ref2 = xchg; |
| } |
| } else { |
| if (ref1->parent != ref2->parent) |
| continue; |
| } |
| |
| eie = ref1->inode_list; |
| while (eie && eie->next) |
| eie = eie->next; |
| if (eie) |
| eie->next = ref2->inode_list; |
| else |
| ref1->inode_list = ref2->inode_list; |
| ref1->count += ref2->count; |
| |
| list_del(&ref2->list); |
| kmem_cache_free(btrfs_prelim_ref_cache, ref2); |
| } |
| |
| } |
| } |
| |
| /* |
| * add all currently queued delayed refs from this head whose seq nr is |
| * smaller or equal that seq to the list |
| */ |
| static int __add_delayed_refs(struct btrfs_delayed_ref_head *head, u64 seq, |
| struct list_head *prefs) |
| { |
| struct btrfs_delayed_extent_op *extent_op = head->extent_op; |
| struct rb_node *n = &head->node.rb_node; |
| struct btrfs_key key; |
| struct btrfs_key op_key = {0}; |
| int sgn; |
| int ret = 0; |
| |
| if (extent_op && extent_op->update_key) |
| btrfs_disk_key_to_cpu(&op_key, &extent_op->key); |
| |
| spin_lock(&head->lock); |
| n = rb_first(&head->ref_root); |
| while (n) { |
| struct btrfs_delayed_ref_node *node; |
| node = rb_entry(n, struct btrfs_delayed_ref_node, |
| rb_node); |
| n = rb_next(n); |
| if (node->seq > seq) |
| continue; |
| |
| switch (node->action) { |
| case BTRFS_ADD_DELAYED_EXTENT: |
| case BTRFS_UPDATE_DELAYED_HEAD: |
| WARN_ON(1); |
| continue; |
| case BTRFS_ADD_DELAYED_REF: |
| sgn = 1; |
| break; |
| case BTRFS_DROP_DELAYED_REF: |
| sgn = -1; |
| break; |
| default: |
| BUG_ON(1); |
| } |
| switch (node->type) { |
| case BTRFS_TREE_BLOCK_REF_KEY: { |
| struct btrfs_delayed_tree_ref *ref; |
| |
| ref = btrfs_delayed_node_to_tree_ref(node); |
| ret = __add_prelim_ref(prefs, ref->root, &op_key, |
| ref->level + 1, 0, node->bytenr, |
| node->ref_mod * sgn, GFP_ATOMIC); |
| break; |
| } |
| case BTRFS_SHARED_BLOCK_REF_KEY: { |
| struct btrfs_delayed_tree_ref *ref; |
| |
| ref = btrfs_delayed_node_to_tree_ref(node); |
| ret = __add_prelim_ref(prefs, ref->root, NULL, |
| ref->level + 1, ref->parent, |
| node->bytenr, |
| node->ref_mod * sgn, GFP_ATOMIC); |
| break; |
| } |
| case BTRFS_EXTENT_DATA_REF_KEY: { |
| struct btrfs_delayed_data_ref *ref; |
| ref = btrfs_delayed_node_to_data_ref(node); |
| |
| key.objectid = ref->objectid; |
| key.type = BTRFS_EXTENT_DATA_KEY; |
| key.offset = ref->offset; |
| ret = __add_prelim_ref(prefs, ref->root, &key, 0, 0, |
| node->bytenr, |
| node->ref_mod * sgn, GFP_ATOMIC); |
| break; |
| } |
| case BTRFS_SHARED_DATA_REF_KEY: { |
| struct btrfs_delayed_data_ref *ref; |
| |
| ref = btrfs_delayed_node_to_data_ref(node); |
| |
| key.objectid = ref->objectid; |
| key.type = BTRFS_EXTENT_DATA_KEY; |
| key.offset = ref->offset; |
| ret = __add_prelim_ref(prefs, ref->root, &key, 0, |
| ref->parent, node->bytenr, |
| node->ref_mod * sgn, GFP_ATOMIC); |
| break; |
| } |
| default: |
| WARN_ON(1); |
| } |
| if (ret) |
| break; |
| } |
| spin_unlock(&head->lock); |
| return ret; |
| } |
| |
| /* |
| * add all inline backrefs for bytenr to the list |
| */ |
| static int __add_inline_refs(struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, u64 bytenr, |
| int *info_level, struct list_head *prefs) |
| { |
| int ret = 0; |
| int slot; |
| struct extent_buffer *leaf; |
| struct btrfs_key key; |
| struct btrfs_key found_key; |
| unsigned long ptr; |
| unsigned long end; |
| struct btrfs_extent_item *ei; |
| u64 flags; |
| u64 item_size; |
| |
| /* |
| * enumerate all inline refs |
| */ |
| leaf = path->nodes[0]; |
| slot = path->slots[0]; |
| |
| item_size = btrfs_item_size_nr(leaf, slot); |
| BUG_ON(item_size < sizeof(*ei)); |
| |
| ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item); |
| flags = btrfs_extent_flags(leaf, ei); |
| btrfs_item_key_to_cpu(leaf, &found_key, slot); |
| |
| ptr = (unsigned long)(ei + 1); |
| end = (unsigned long)ei + item_size; |
| |
| if (found_key.type == BTRFS_EXTENT_ITEM_KEY && |
| flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { |
| struct btrfs_tree_block_info *info; |
| |
| info = (struct btrfs_tree_block_info *)ptr; |
| *info_level = btrfs_tree_block_level(leaf, info); |
| ptr += sizeof(struct btrfs_tree_block_info); |
| BUG_ON(ptr > end); |
| } else if (found_key.type == BTRFS_METADATA_ITEM_KEY) { |
| *info_level = found_key.offset; |
| } else { |
| BUG_ON(!(flags & BTRFS_EXTENT_FLAG_DATA)); |
| } |
| |
| while (ptr < end) { |
| struct btrfs_extent_inline_ref *iref; |
| u64 offset; |
| int type; |
| |
| iref = (struct btrfs_extent_inline_ref *)ptr; |
| type = btrfs_extent_inline_ref_type(leaf, iref); |
| offset = btrfs_extent_inline_ref_offset(leaf, iref); |
| |
| switch (type) { |
| case BTRFS_SHARED_BLOCK_REF_KEY: |
| ret = __add_prelim_ref(prefs, 0, NULL, |
| *info_level + 1, offset, |
| bytenr, 1, GFP_NOFS); |
| break; |
| case BTRFS_SHARED_DATA_REF_KEY: { |
| struct btrfs_shared_data_ref *sdref; |
| int count; |
| |
| sdref = (struct btrfs_shared_data_ref *)(iref + 1); |
| count = btrfs_shared_data_ref_count(leaf, sdref); |
| ret = __add_prelim_ref(prefs, 0, NULL, 0, offset, |
| bytenr, count, GFP_NOFS); |
| break; |
| } |
| case BTRFS_TREE_BLOCK_REF_KEY: |
| ret = __add_prelim_ref(prefs, offset, NULL, |
| *info_level + 1, 0, |
| bytenr, 1, GFP_NOFS); |
| break; |
| case BTRFS_EXTENT_DATA_REF_KEY: { |
| struct btrfs_extent_data_ref *dref; |
| int count; |
| u64 root; |
| |
| dref = (struct btrfs_extent_data_ref *)(&iref->offset); |
| count = btrfs_extent_data_ref_count(leaf, dref); |
| key.objectid = btrfs_extent_data_ref_objectid(leaf, |
| dref); |
| key.type = BTRFS_EXTENT_DATA_KEY; |
| key.offset = btrfs_extent_data_ref_offset(leaf, dref); |
| root = btrfs_extent_data_ref_root(leaf, dref); |
| ret = __add_prelim_ref(prefs, root, &key, 0, 0, |
| bytenr, count, GFP_NOFS); |
| break; |
| } |
| default: |
| WARN_ON(1); |
| } |
| if (ret) |
| return ret; |
| ptr += btrfs_extent_inline_ref_size(type); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * add all non-inline backrefs for bytenr to the list |
| */ |
| static int __add_keyed_refs(struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, u64 bytenr, |
| int info_level, struct list_head *prefs) |
| { |
| struct btrfs_root *extent_root = fs_info->extent_root; |
| int ret; |
| int slot; |
| struct extent_buffer *leaf; |
| struct btrfs_key key; |
| |
| while (1) { |
| ret = btrfs_next_item(extent_root, path); |
| if (ret < 0) |
| break; |
| if (ret) { |
| ret = 0; |
| break; |
| } |
| |
| slot = path->slots[0]; |
| leaf = path->nodes[0]; |
| btrfs_item_key_to_cpu(leaf, &key, slot); |
| |
| if (key.objectid != bytenr) |
| break; |
| if (key.type < BTRFS_TREE_BLOCK_REF_KEY) |
| continue; |
| if (key.type > BTRFS_SHARED_DATA_REF_KEY) |
| break; |
| |
| switch (key.type) { |
| case BTRFS_SHARED_BLOCK_REF_KEY: |
| ret = __add_prelim_ref(prefs, 0, NULL, |
| info_level + 1, key.offset, |
| bytenr, 1, GFP_NOFS); |
| break; |
| case BTRFS_SHARED_DATA_REF_KEY: { |
| struct btrfs_shared_data_ref *sdref; |
| int count; |
| |
| sdref = btrfs_item_ptr(leaf, slot, |
| struct btrfs_shared_data_ref); |
| count = btrfs_shared_data_ref_count(leaf, sdref); |
| ret = __add_prelim_ref(prefs, 0, NULL, 0, key.offset, |
| bytenr, count, GFP_NOFS); |
| break; |
| } |
| case BTRFS_TREE_BLOCK_REF_KEY: |
| ret = __add_prelim_ref(prefs, key.offset, NULL, |
| info_level + 1, 0, |
| bytenr, 1, GFP_NOFS); |
| break; |
| case BTRFS_EXTENT_DATA_REF_KEY: { |
| struct btrfs_extent_data_ref *dref; |
| int count; |
| u64 root; |
| |
| dref = btrfs_item_ptr(leaf, slot, |
| struct btrfs_extent_data_ref); |
| count = btrfs_extent_data_ref_count(leaf, dref); |
| key.objectid = btrfs_extent_data_ref_objectid(leaf, |
| dref); |
| key.type = BTRFS_EXTENT_DATA_KEY; |
| key.offset = btrfs_extent_data_ref_offset(leaf, dref); |
| root = btrfs_extent_data_ref_root(leaf, dref); |
| ret = __add_prelim_ref(prefs, root, &key, 0, 0, |
| bytenr, count, GFP_NOFS); |
| break; |
| } |
| default: |
| WARN_ON(1); |
| } |
| if (ret) |
| return ret; |
| |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * this adds all existing backrefs (inline backrefs, backrefs and delayed |
| * refs) for the given bytenr to the refs list, merges duplicates and resolves |
| * indirect refs to their parent bytenr. |
| * When roots are found, they're added to the roots list |
| * |
| * FIXME some caching might speed things up |
| */ |
| static int find_parent_nodes(struct btrfs_trans_handle *trans, |
| struct btrfs_fs_info *fs_info, u64 bytenr, |
| u64 time_seq, struct ulist *refs, |
| struct ulist *roots, const u64 *extent_item_pos) |
| { |
| struct btrfs_key key; |
| struct btrfs_path *path; |
| struct btrfs_delayed_ref_root *delayed_refs = NULL; |
| struct btrfs_delayed_ref_head *head; |
| int info_level = 0; |
| int ret; |
| struct list_head prefs_delayed; |
| struct list_head prefs; |
| struct __prelim_ref *ref; |
| |
| INIT_LIST_HEAD(&prefs); |
| INIT_LIST_HEAD(&prefs_delayed); |
| |
| key.objectid = bytenr; |
| key.offset = (u64)-1; |
| if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) |
| key.type = BTRFS_METADATA_ITEM_KEY; |
| else |
| key.type = BTRFS_EXTENT_ITEM_KEY; |
| |
| path = btrfs_alloc_path(); |
| if (!path) |
| return -ENOMEM; |
| if (!trans) |
| path->search_commit_root = 1; |
| |
| /* |
| * grab both a lock on the path and a lock on the delayed ref head. |
| * We need both to get a consistent picture of how the refs look |
| * at a specified point in time |
| */ |
| again: |
| head = NULL; |
| |
| ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0); |
| if (ret < 0) |
| goto out; |
| BUG_ON(ret == 0); |
| |
| if (trans) { |
| /* |
| * look if there are updates for this ref queued and lock the |
| * head |
| */ |
| delayed_refs = &trans->transaction->delayed_refs; |
| spin_lock(&delayed_refs->lock); |
| head = btrfs_find_delayed_ref_head(trans, bytenr); |
| if (head) { |
| if (!mutex_trylock(&head->mutex)) { |
| atomic_inc(&head->node.refs); |
| spin_unlock(&delayed_refs->lock); |
| |
| btrfs_release_path(path); |
| |
| /* |
| * Mutex was contended, block until it's |
| * released and try again |
| */ |
| mutex_lock(&head->mutex); |
| mutex_unlock(&head->mutex); |
| btrfs_put_delayed_ref(&head->node); |
| goto again; |
| } |
| spin_unlock(&delayed_refs->lock); |
| ret = __add_delayed_refs(head, time_seq, |
| &prefs_delayed); |
| mutex_unlock(&head->mutex); |
| if (ret) |
| goto out; |
| } else { |
| spin_unlock(&delayed_refs->lock); |
| } |
| } |
| |
| if (path->slots[0]) { |
| struct extent_buffer *leaf; |
| int slot; |
| |
| path->slots[0]--; |
| leaf = path->nodes[0]; |
| slot = path->slots[0]; |
| btrfs_item_key_to_cpu(leaf, &key, slot); |
| if (key.objectid == bytenr && |
| (key.type == BTRFS_EXTENT_ITEM_KEY || |
| key.type == BTRFS_METADATA_ITEM_KEY)) { |
| ret = __add_inline_refs(fs_info, path, bytenr, |
| &info_level, &prefs); |
| if (ret) |
| goto out; |
| ret = __add_keyed_refs(fs_info, path, bytenr, |
| info_level, &prefs); |
| if (ret) |
| goto out; |
| } |
| } |
| btrfs_release_path(path); |
| |
| list_splice_init(&prefs_delayed, &prefs); |
| |
| ret = __add_missing_keys(fs_info, &prefs); |
| if (ret) |
| goto out; |
| |
| __merge_refs(&prefs, 1); |
| |
| ret = __resolve_indirect_refs(fs_info, path, time_seq, &prefs, |
| extent_item_pos); |
| if (ret) |
| goto out; |
| |
| __merge_refs(&prefs, 2); |
| |
| while (!list_empty(&prefs)) { |
| ref = list_first_entry(&prefs, struct __prelim_ref, list); |
| WARN_ON(ref->count < 0); |
| if (ref->count && ref->root_id && ref->parent == 0) { |
| /* no parent == root of tree */ |
| ret = ulist_add(roots, ref->root_id, 0, GFP_NOFS); |
| if (ret < 0) |
| goto out; |
| } |
| if (ref->count && ref->parent) { |
| struct extent_inode_elem *eie = NULL; |
| if (extent_item_pos && !ref->inode_list) { |
| u32 bsz; |
| struct extent_buffer *eb; |
| bsz = btrfs_level_size(fs_info->extent_root, |
| info_level); |
| eb = read_tree_block(fs_info->extent_root, |
| ref->parent, bsz, 0); |
| if (!eb || !extent_buffer_uptodate(eb)) { |
| free_extent_buffer(eb); |
| ret = -EIO; |
| goto out; |
| } |
| ret = find_extent_in_eb(eb, bytenr, |
| *extent_item_pos, &eie); |
| free_extent_buffer(eb); |
| if (ret < 0) |
| goto out; |
| ref->inode_list = eie; |
| } |
| ret = ulist_add_merge(refs, ref->parent, |
| (uintptr_t)ref->inode_list, |
| (u64 *)&eie, GFP_NOFS); |
| if (ret < 0) |
| goto out; |
| if (!ret && extent_item_pos) { |
| /* |
| * we've recorded that parent, so we must extend |
| * its inode list here |
| */ |
| BUG_ON(!eie); |
| while (eie->next) |
| eie = eie->next; |
| eie->next = ref->inode_list; |
| } |
| } |
| list_del(&ref->list); |
| kmem_cache_free(btrfs_prelim_ref_cache, ref); |
| } |
| |
| out: |
| btrfs_free_path(path); |
| while (!list_empty(&prefs)) { |
| ref = list_first_entry(&prefs, struct __prelim_ref, list); |
| list_del(&ref->list); |
| kmem_cache_free(btrfs_prelim_ref_cache, ref); |
| } |
| while (!list_empty(&prefs_delayed)) { |
| ref = list_first_entry(&prefs_delayed, struct __prelim_ref, |
| list); |
| list_del(&ref->list); |
| kmem_cache_free(btrfs_prelim_ref_cache, ref); |
| } |
| |
| return ret; |
| } |
| |
| static void free_leaf_list(struct ulist *blocks) |
| { |
| struct ulist_node *node = NULL; |
| struct extent_inode_elem *eie; |
| struct extent_inode_elem *eie_next; |
| struct ulist_iterator uiter; |
| |
| ULIST_ITER_INIT(&uiter); |
| while ((node = ulist_next(blocks, &uiter))) { |
| if (!node->aux) |
| continue; |
| eie = (struct extent_inode_elem *)(uintptr_t)node->aux; |
| for (; eie; eie = eie_next) { |
| eie_next = eie->next; |
| kfree(eie); |
| } |
| node->aux = 0; |
| } |
| |
| ulist_free(blocks); |
| } |
| |
| /* |
| * Finds all leafs with a reference to the specified combination of bytenr and |
| * offset. key_list_head will point to a list of corresponding keys (caller must |
| * free each list element). The leafs will be stored in the leafs ulist, which |
| * must be freed with ulist_free. |
| * |
| * returns 0 on success, <0 on error |
| */ |
| static int btrfs_find_all_leafs(struct btrfs_trans_handle *trans, |
| struct btrfs_fs_info *fs_info, u64 bytenr, |
| u64 time_seq, struct ulist **leafs, |
| const u64 *extent_item_pos) |
| { |
| struct ulist *tmp; |
| int ret; |
| |
| tmp = ulist_alloc(GFP_NOFS); |
| if (!tmp) |
| return -ENOMEM; |
| *leafs = ulist_alloc(GFP_NOFS); |
| if (!*leafs) { |
| ulist_free(tmp); |
| return -ENOMEM; |
| } |
| |
| ret = find_parent_nodes(trans, fs_info, bytenr, |
| time_seq, *leafs, tmp, extent_item_pos); |
| ulist_free(tmp); |
| |
| if (ret < 0 && ret != -ENOENT) { |
| free_leaf_list(*leafs); |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * walk all backrefs for a given extent to find all roots that reference this |
| * extent. Walking a backref means finding all extents that reference this |
| * extent and in turn walk the backrefs of those, too. Naturally this is a |
| * recursive process, but here it is implemented in an iterative fashion: We |
| * find all referencing extents for the extent in question and put them on a |
| * list. In turn, we find all referencing extents for those, further appending |
| * to the list. The way we iterate the list allows adding more elements after |
| * the current while iterating. The process stops when we reach the end of the |
| * list. Found roots are added to the roots list. |
| * |
| * returns 0 on success, < 0 on error. |
| */ |
| int btrfs_find_all_roots(struct btrfs_trans_handle *trans, |
| struct btrfs_fs_info *fs_info, u64 bytenr, |
| u64 time_seq, struct ulist **roots) |
| { |
| struct ulist *tmp; |
| struct ulist_node *node = NULL; |
| struct ulist_iterator uiter; |
| int ret; |
| |
| tmp = ulist_alloc(GFP_NOFS); |
| if (!tmp) |
| return -ENOMEM; |
| *roots = ulist_alloc(GFP_NOFS); |
| if (!*roots) { |
| ulist_free(tmp); |
| return -ENOMEM; |
| } |
| |
| ULIST_ITER_INIT(&uiter); |
| while (1) { |
| ret = find_parent_nodes(trans, fs_info, bytenr, |
| time_seq, tmp, *roots, NULL); |
| if (ret < 0 && ret != -ENOENT) { |
| ulist_free(tmp); |
| ulist_free(*roots); |
| return ret; |
| } |
| node = ulist_next(tmp, &uiter); |
| if (!node) |
| break; |
| bytenr = node->val; |
| } |
| |
| ulist_free(tmp); |
| return 0; |
| } |
| |
| /* |
| * this makes the path point to (inum INODE_ITEM ioff) |
| */ |
| int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, |
| struct btrfs_path *path) |
| { |
| struct btrfs_key key; |
| return btrfs_find_item(fs_root, path, inum, ioff, |
| BTRFS_INODE_ITEM_KEY, &key); |
| } |
| |
| static int inode_ref_info(u64 inum, u64 ioff, struct btrfs_root *fs_root, |
| struct btrfs_path *path, |
| struct btrfs_key *found_key) |
| { |
| return btrfs_find_item(fs_root, path, inum, ioff, |
| BTRFS_INODE_REF_KEY, found_key); |
| } |
| |
| int btrfs_find_one_extref(struct btrfs_root *root, u64 inode_objectid, |
| u64 start_off, struct btrfs_path *path, |
| struct btrfs_inode_extref **ret_extref, |
| u64 *found_off) |
| { |
| int ret, slot; |
| struct btrfs_key key; |
| struct btrfs_key found_key; |
| struct btrfs_inode_extref *extref; |
| struct extent_buffer *leaf; |
| unsigned long ptr; |
| |
| key.objectid = inode_objectid; |
| btrfs_set_key_type(&key, BTRFS_INODE_EXTREF_KEY); |
| key.offset = start_off; |
| |
| ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| while (1) { |
| leaf = path->nodes[0]; |
| slot = path->slots[0]; |
| if (slot >= btrfs_header_nritems(leaf)) { |
| /* |
| * If the item at offset is not found, |
| * btrfs_search_slot will point us to the slot |
| * where it should be inserted. In our case |
| * that will be the slot directly before the |
| * next INODE_REF_KEY_V2 item. In the case |
| * that we're pointing to the last slot in a |
| * leaf, we must move one leaf over. |
| */ |
| ret = btrfs_next_leaf(root, path); |
| if (ret) { |
| if (ret >= 1) |
| ret = -ENOENT; |
| break; |
| } |
| continue; |
| } |
| |
| btrfs_item_key_to_cpu(leaf, &found_key, slot); |
| |
| /* |
| * Check that we're still looking at an extended ref key for |
| * this particular objectid. If we have different |
| * objectid or type then there are no more to be found |
| * in the tree and we can exit. |
| */ |
| ret = -ENOENT; |
| if (found_key.objectid != inode_objectid) |
| break; |
| if (btrfs_key_type(&found_key) != BTRFS_INODE_EXTREF_KEY) |
| break; |
| |
| ret = 0; |
| ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
| extref = (struct btrfs_inode_extref *)ptr; |
| *ret_extref = extref; |
| if (found_off) |
| *found_off = found_key.offset; |
| break; |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * this iterates to turn a name (from iref/extref) into a full filesystem path. |
| * Elements of the path are separated by '/' and the path is guaranteed to be |
| * 0-terminated. the path is only given within the current file system. |
| * Therefore, it never starts with a '/'. the caller is responsible to provide |
| * "size" bytes in "dest". the dest buffer will be filled backwards. finally, |
| * the start point of the resulting string is returned. this pointer is within |
| * dest, normally. |
| * in case the path buffer would overflow, the pointer is decremented further |
| * as if output was written to the buffer, though no more output is actually |
| * generated. that way, the caller can determine how much space would be |
| * required for the path to fit into the buffer. in that case, the returned |
| * value will be smaller than dest. callers must check this! |
| */ |
| char *btrfs_ref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path, |
| u32 name_len, unsigned long name_off, |
| struct extent_buffer *eb_in, u64 parent, |
| char *dest, u32 size) |
| { |
| int slot; |
| u64 next_inum; |
| int ret; |
| s64 bytes_left = ((s64)size) - 1; |
| struct extent_buffer *eb = eb_in; |
| struct btrfs_key found_key; |
| int leave_spinning = path->leave_spinning; |
| struct btrfs_inode_ref *iref; |
| |
| if (bytes_left >= 0) |
| dest[bytes_left] = '\0'; |
| |
| path->leave_spinning = 1; |
| while (1) { |
| bytes_left -= name_len; |
| if (bytes_left >= 0) |
| read_extent_buffer(eb, dest + bytes_left, |
| name_off, name_len); |
| if (eb != eb_in) { |
| btrfs_tree_read_unlock_blocking(eb); |
| free_extent_buffer(eb); |
| } |
| ret = inode_ref_info(parent, 0, fs_root, path, &found_key); |
| if (ret > 0) |
| ret = -ENOENT; |
| if (ret) |
| break; |
| |
| next_inum = found_key.offset; |
| |
| /* regular exit ahead */ |
| if (parent == next_inum) |
| break; |
| |
| slot = path->slots[0]; |
| eb = path->nodes[0]; |
| /* make sure we can use eb after releasing the path */ |
| if (eb != eb_in) { |
| atomic_inc(&eb->refs); |
| btrfs_tree_read_lock(eb); |
| btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); |
| } |
| btrfs_release_path(path); |
| iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); |
| |
| name_len = btrfs_inode_ref_name_len(eb, iref); |
| name_off = (unsigned long)(iref + 1); |
| |
| parent = next_inum; |
| --bytes_left; |
| if (bytes_left >= 0) |
| dest[bytes_left] = '/'; |
| } |
| |
| btrfs_release_path(path); |
| path->leave_spinning = leave_spinning; |
| |
| if (ret) |
| return ERR_PTR(ret); |
| |
| return dest + bytes_left; |
| } |
| |
| /* |
| * this makes the path point to (logical EXTENT_ITEM *) |
| * returns BTRFS_EXTENT_FLAG_DATA for data, BTRFS_EXTENT_FLAG_TREE_BLOCK for |
| * tree blocks and <0 on error. |
| */ |
| int extent_from_logical(struct btrfs_fs_info *fs_info, u64 logical, |
| struct btrfs_path *path, struct btrfs_key *found_key, |
| u64 *flags_ret) |
| { |
| int ret; |
| u64 flags; |
| u64 size = 0; |
| u32 item_size; |
| struct extent_buffer *eb; |
| struct btrfs_extent_item *ei; |
| struct btrfs_key key; |
| |
| if (btrfs_fs_incompat(fs_info, SKINNY_METADATA)) |
| key.type = BTRFS_METADATA_ITEM_KEY; |
| else |
| key.type = BTRFS_EXTENT_ITEM_KEY; |
| key.objectid = logical; |
| key.offset = (u64)-1; |
| |
| ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0); |
| if (ret < 0) |
| return ret; |
| |
| while (1) { |
| u32 nritems; |
| if (path->slots[0] == 0) { |
| btrfs_set_path_blocking(path); |
| ret = btrfs_prev_leaf(fs_info->extent_root, path); |
| if (ret != 0) { |
| if (ret > 0) { |
| pr_debug("logical %llu is not within " |
| "any extent\n", logical); |
| ret = -ENOENT; |
| } |
| return ret; |
| } |
| } else { |
| path->slots[0]--; |
| } |
| nritems = btrfs_header_nritems(path->nodes[0]); |
| if (nritems == 0) { |
| pr_debug("logical %llu is not within any extent\n", |
| logical); |
| return -ENOENT; |
| } |
| if (path->slots[0] == nritems) |
| path->slots[0]--; |
| |
| btrfs_item_key_to_cpu(path->nodes[0], found_key, |
| path->slots[0]); |
| if (found_key->type == BTRFS_EXTENT_ITEM_KEY || |
| found_key->type == BTRFS_METADATA_ITEM_KEY) |
| break; |
| } |
| |
| if (found_key->type == BTRFS_METADATA_ITEM_KEY) |
| size = fs_info->extent_root->leafsize; |
| else if (found_key->type == BTRFS_EXTENT_ITEM_KEY) |
| size = found_key->offset; |
| |
| if (found_key->objectid > logical || |
| found_key->objectid + size <= logical) { |
| pr_debug("logical %llu is not within any extent\n", logical); |
| return -ENOENT; |
| } |
| |
| eb = path->nodes[0]; |
| item_size = btrfs_item_size_nr(eb, path->slots[0]); |
| BUG_ON(item_size < sizeof(*ei)); |
| |
| ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item); |
| flags = btrfs_extent_flags(eb, ei); |
| |
| pr_debug("logical %llu is at position %llu within the extent (%llu " |
| "EXTENT_ITEM %llu) flags %#llx size %u\n", |
| logical, logical - found_key->objectid, found_key->objectid, |
| found_key->offset, flags, item_size); |
| |
| WARN_ON(!flags_ret); |
| if (flags_ret) { |
| if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
| *flags_ret = BTRFS_EXTENT_FLAG_TREE_BLOCK; |
| else if (flags & BTRFS_EXTENT_FLAG_DATA) |
| *flags_ret = BTRFS_EXTENT_FLAG_DATA; |
| else |
| BUG_ON(1); |
| return 0; |
| } |
| |
| return -EIO; |
| } |
| |
| /* |
| * helper function to iterate extent inline refs. ptr must point to a 0 value |
| * for the first call and may be modified. it is used to track state. |
| * if more refs exist, 0 is returned and the next call to |
| * __get_extent_inline_ref must pass the modified ptr parameter to get the |
| * next ref. after the last ref was processed, 1 is returned. |
| * returns <0 on error |
| */ |
| static int __get_extent_inline_ref(unsigned long *ptr, struct extent_buffer *eb, |
| struct btrfs_extent_item *ei, u32 item_size, |
| struct btrfs_extent_inline_ref **out_eiref, |
| int *out_type) |
| { |
| unsigned long end; |
| u64 flags; |
| struct btrfs_tree_block_info *info; |
| |
| if (!*ptr) { |
| /* first call */ |
| flags = btrfs_extent_flags(eb, ei); |
| if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) { |
| info = (struct btrfs_tree_block_info *)(ei + 1); |
| *out_eiref = |
| (struct btrfs_extent_inline_ref *)(info + 1); |
| } else { |
| *out_eiref = (struct btrfs_extent_inline_ref *)(ei + 1); |
| } |
| *ptr = (unsigned long)*out_eiref; |
| if ((void *)*ptr >= (void *)ei + item_size) |
| return -ENOENT; |
| } |
| |
| end = (unsigned long)ei + item_size; |
| *out_eiref = (struct btrfs_extent_inline_ref *)*ptr; |
| *out_type = btrfs_extent_inline_ref_type(eb, *out_eiref); |
| |
| *ptr += btrfs_extent_inline_ref_size(*out_type); |
| WARN_ON(*ptr > end); |
| if (*ptr == end) |
| return 1; /* last */ |
| |
| return 0; |
| } |
| |
| /* |
| * reads the tree block backref for an extent. tree level and root are returned |
| * through out_level and out_root. ptr must point to a 0 value for the first |
| * call and may be modified (see __get_extent_inline_ref comment). |
| * returns 0 if data was provided, 1 if there was no more data to provide or |
| * <0 on error. |
| */ |
| int tree_backref_for_extent(unsigned long *ptr, struct extent_buffer *eb, |
| struct btrfs_extent_item *ei, u32 item_size, |
| u64 *out_root, u8 *out_level) |
| { |
| int ret; |
| int type; |
| struct btrfs_tree_block_info *info; |
| struct btrfs_extent_inline_ref *eiref; |
| |
| if (*ptr == (unsigned long)-1) |
| return 1; |
| |
| while (1) { |
| ret = __get_extent_inline_ref(ptr, eb, ei, item_size, |
| &eiref, &type); |
| if (ret < 0) |
| return ret; |
| |
| if (type == BTRFS_TREE_BLOCK_REF_KEY || |
| type == BTRFS_SHARED_BLOCK_REF_KEY) |
| break; |
| |
| if (ret == 1) |
| return 1; |
| } |
| |
| /* we can treat both ref types equally here */ |
| info = (struct btrfs_tree_block_info *)(ei + 1); |
| *out_root = btrfs_extent_inline_ref_offset(eb, eiref); |
| *out_level = btrfs_tree_block_level(eb, info); |
| |
| if (ret == 1) |
| *ptr = (unsigned long)-1; |
| |
| return 0; |
| } |
| |
| static int iterate_leaf_refs(struct extent_inode_elem *inode_list, |
| u64 root, u64 extent_item_objectid, |
| iterate_extent_inodes_t *iterate, void *ctx) |
| { |
| struct extent_inode_elem *eie; |
| int ret = 0; |
| |
| for (eie = inode_list; eie; eie = eie->next) { |
| pr_debug("ref for %llu resolved, key (%llu EXTEND_DATA %llu), " |
| "root %llu\n", extent_item_objectid, |
| eie->inum, eie->offset, root); |
| ret = iterate(eie->inum, eie->offset, root, ctx); |
| if (ret) { |
| pr_debug("stopping iteration for %llu due to ret=%d\n", |
| extent_item_objectid, ret); |
| break; |
| } |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * calls iterate() for every inode that references the extent identified by |
| * the given parameters. |
| * when the iterator function returns a non-zero value, iteration stops. |
| */ |
| int iterate_extent_inodes(struct btrfs_fs_info *fs_info, |
| u64 extent_item_objectid, u64 extent_item_pos, |
| int search_commit_root, |
| iterate_extent_inodes_t *iterate, void *ctx) |
| { |
| int ret; |
| struct btrfs_trans_handle *trans = NULL; |
| struct ulist *refs = NULL; |
| struct ulist *roots = NULL; |
| struct ulist_node *ref_node = NULL; |
| struct ulist_node *root_node = NULL; |
| struct seq_list tree_mod_seq_elem = {}; |
| struct ulist_iterator ref_uiter; |
| struct ulist_iterator root_uiter; |
| |
| pr_debug("resolving all inodes for extent %llu\n", |
| extent_item_objectid); |
| |
| if (!search_commit_root) { |
| trans = btrfs_join_transaction(fs_info->extent_root); |
| if (IS_ERR(trans)) |
| return PTR_ERR(trans); |
| btrfs_get_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
| } |
| |
| ret = btrfs_find_all_leafs(trans, fs_info, extent_item_objectid, |
| tree_mod_seq_elem.seq, &refs, |
| &extent_item_pos); |
| if (ret) |
| goto out; |
| |
| ULIST_ITER_INIT(&ref_uiter); |
| while (!ret && (ref_node = ulist_next(refs, &ref_uiter))) { |
| ret = btrfs_find_all_roots(trans, fs_info, ref_node->val, |
| tree_mod_seq_elem.seq, &roots); |
| if (ret) |
| break; |
| ULIST_ITER_INIT(&root_uiter); |
| while (!ret && (root_node = ulist_next(roots, &root_uiter))) { |
| pr_debug("root %llu references leaf %llu, data list " |
| "%#llx\n", root_node->val, ref_node->val, |
| ref_node->aux); |
| ret = iterate_leaf_refs((struct extent_inode_elem *) |
| (uintptr_t)ref_node->aux, |
| root_node->val, |
| extent_item_objectid, |
| iterate, ctx); |
| } |
| ulist_free(roots); |
| } |
| |
| free_leaf_list(refs); |
| out: |
| if (!search_commit_root) { |
| btrfs_put_tree_mod_seq(fs_info, &tree_mod_seq_elem); |
| btrfs_end_transaction(trans, fs_info->extent_root); |
| } |
| |
| return ret; |
| } |
| |
| int iterate_inodes_from_logical(u64 logical, struct btrfs_fs_info *fs_info, |
| struct btrfs_path *path, |
| iterate_extent_inodes_t *iterate, void *ctx) |
| { |
| int ret; |
| u64 extent_item_pos; |
| u64 flags = 0; |
| struct btrfs_key found_key; |
| int search_commit_root = path->search_commit_root; |
| |
| ret = extent_from_logical(fs_info, logical, path, &found_key, &flags); |
| btrfs_release_path(path); |
| if (ret < 0) |
| return ret; |
| if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) |
| return -EINVAL; |
| |
| extent_item_pos = logical - found_key.objectid; |
| ret = iterate_extent_inodes(fs_info, found_key.objectid, |
| extent_item_pos, search_commit_root, |
| iterate, ctx); |
| |
| return ret; |
| } |
| |
| typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off, |
| struct extent_buffer *eb, void *ctx); |
| |
| static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root, |
| struct btrfs_path *path, |
| iterate_irefs_t *iterate, void *ctx) |
| { |
| int ret = 0; |
| int slot; |
| u32 cur; |
| u32 len; |
| u32 name_len; |
| u64 parent = 0; |
| int found = 0; |
| struct extent_buffer *eb; |
| struct btrfs_item *item; |
| struct btrfs_inode_ref *iref; |
| struct btrfs_key found_key; |
| |
| while (!ret) { |
| ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path, |
| &found_key); |
| if (ret < 0) |
| break; |
| if (ret) { |
| ret = found ? 0 : -ENOENT; |
| break; |
| } |
| ++found; |
| |
| parent = found_key.offset; |
| slot = path->slots[0]; |
| eb = btrfs_clone_extent_buffer(path->nodes[0]); |
| if (!eb) { |
| ret = -ENOMEM; |
| break; |
| } |
| extent_buffer_get(eb); |
| btrfs_tree_read_lock(eb); |
| btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); |
| btrfs_release_path(path); |
| |
| item = btrfs_item_nr(slot); |
| iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref); |
| |
| for (cur = 0; cur < btrfs_item_size(eb, item); cur += len) { |
| name_len = btrfs_inode_ref_name_len(eb, iref); |
| /* path must be released before calling iterate()! */ |
| pr_debug("following ref at offset %u for inode %llu in " |
| "tree %llu\n", cur, found_key.objectid, |
| fs_root->objectid); |
| ret = iterate(parent, name_len, |
| (unsigned long)(iref + 1), eb, ctx); |
| if (ret) |
| break; |
| len = sizeof(*iref) + name_len; |
| iref = (struct btrfs_inode_ref *)((char *)iref + len); |
| } |
| btrfs_tree_read_unlock_blocking(eb); |
| free_extent_buffer(eb); |
| } |
| |
| btrfs_release_path(path); |
| |
| return ret; |
| } |
| |
| static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root, |
| struct btrfs_path *path, |
| iterate_irefs_t *iterate, void *ctx) |
| { |
| int ret; |
| int slot; |
| u64 offset = 0; |
| u64 parent; |
| int found = 0; |
| struct extent_buffer *eb; |
| struct btrfs_inode_extref *extref; |
| struct extent_buffer *leaf; |
| u32 item_size; |
| u32 cur_offset; |
| unsigned long ptr; |
| |
| while (1) { |
| ret = btrfs_find_one_extref(fs_root, inum, offset, path, &extref, |
| &offset); |
| if (ret < 0) |
| break; |
| if (ret) { |
| ret = found ? 0 : -ENOENT; |
| break; |
| } |
| ++found; |
| |
| slot = path->slots[0]; |
| eb = btrfs_clone_extent_buffer(path->nodes[0]); |
| if (!eb) { |
| ret = -ENOMEM; |
| break; |
| } |
| extent_buffer_get(eb); |
| |
| btrfs_tree_read_lock(eb); |
| btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK); |
| btrfs_release_path(path); |
| |
| leaf = path->nodes[0]; |
| item_size = btrfs_item_size_nr(leaf, slot); |
| ptr = btrfs_item_ptr_offset(leaf, slot); |
| cur_offset = 0; |
| |
| while (cur_offset < item_size) { |
| u32 name_len; |
| |
| extref = (struct btrfs_inode_extref *)(ptr + cur_offset); |
| parent = btrfs_inode_extref_parent(eb, extref); |
| name_len = btrfs_inode_extref_name_len(eb, extref); |
| ret = iterate(parent, name_len, |
| (unsigned long)&extref->name, eb, ctx); |
| if (ret) |
| break; |
| |
| cur_offset += btrfs_inode_extref_name_len(leaf, extref); |
| cur_offset += sizeof(*extref); |
| } |
| btrfs_tree_read_unlock_blocking(eb); |
| free_extent_buffer(eb); |
| |
| offset++; |
| } |
| |
| btrfs_release_path(path); |
| |
| return ret; |
| } |
| |
| static int iterate_irefs(u64 inum, struct btrfs_root *fs_root, |
| struct btrfs_path *path, iterate_irefs_t *iterate, |
| void *ctx) |
| { |
| int ret; |
| int found_refs = 0; |
| |
| ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx); |
| if (!ret) |
| ++found_refs; |
| else if (ret != -ENOENT) |
| return ret; |
| |
| ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx); |
| if (ret == -ENOENT && found_refs) |
| return 0; |
| |
| return ret; |
| } |
| |
| /* |
| * returns 0 if the path could be dumped (probably truncated) |
| * returns <0 in case of an error |
| */ |
| static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off, |
| struct extent_buffer *eb, void *ctx) |
| { |
| struct inode_fs_paths *ipath = ctx; |
| char *fspath; |
| char *fspath_min; |
| int i = ipath->fspath->elem_cnt; |
| const int s_ptr = sizeof(char *); |
| u32 bytes_left; |
| |
| bytes_left = ipath->fspath->bytes_left > s_ptr ? |
| ipath->fspath->bytes_left - s_ptr : 0; |
| |
| fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr; |
| fspath = btrfs_ref_to_path(ipath->fs_root, ipath->btrfs_path, name_len, |
| name_off, eb, inum, fspath_min, bytes_left); |
| if (IS_ERR(fspath)) |
| return PTR_ERR(fspath); |
| |
| if (fspath > fspath_min) { |
| ipath->fspath->val[i] = (u64)(unsigned long)fspath; |
| ++ipath->fspath->elem_cnt; |
| ipath->fspath->bytes_left = fspath - fspath_min; |
| } else { |
| ++ipath->fspath->elem_missed; |
| ipath->fspath->bytes_missing += fspath_min - fspath; |
| ipath->fspath->bytes_left = 0; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * this dumps all file system paths to the inode into the ipath struct, provided |
| * is has been created large enough. each path is zero-terminated and accessed |
| * from ipath->fspath->val[i]. |
| * when it returns, there are ipath->fspath->elem_cnt number of paths available |
| * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the |
| * number of missed paths in recored in ipath->fspath->elem_missed, otherwise, |
| * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would |
| * have been needed to return all paths. |
| */ |
| int paths_from_inode(u64 inum, struct inode_fs_paths *ipath) |
| { |
| return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path, |
| inode_to_path, ipath); |
| } |
| |
| struct btrfs_data_container *init_data_container(u32 total_bytes) |
| { |
| struct btrfs_data_container *data; |
| size_t alloc_bytes; |
| |
| alloc_bytes = max_t(size_t, total_bytes, sizeof(*data)); |
| data = vmalloc(alloc_bytes); |
| if (!data) |
| return ERR_PTR(-ENOMEM); |
| |
| if (total_bytes >= sizeof(*data)) { |
| data->bytes_left = total_bytes - sizeof(*data); |
| data->bytes_missing = 0; |
| } else { |
| data->bytes_missing = sizeof(*data) - total_bytes; |
| data->bytes_left = 0; |
| } |
| |
| data->elem_cnt = 0; |
| data->elem_missed = 0; |
| |
| return data; |
| } |
| |
| /* |
| * allocates space to return multiple file system paths for an inode. |
| * total_bytes to allocate are passed, note that space usable for actual path |
| * information will be total_bytes - sizeof(struct inode_fs_paths). |
| * the returned pointer must be freed with free_ipath() in the end. |
| */ |
| struct inode_fs_paths *init_ipath(s32 total_bytes, struct btrfs_root *fs_root, |
| struct btrfs_path *path) |
| { |
| struct inode_fs_paths *ifp; |
| struct btrfs_data_container *fspath; |
| |
| fspath = init_data_container(total_bytes); |
| if (IS_ERR(fspath)) |
| return (void *)fspath; |
| |
| ifp = kmalloc(sizeof(*ifp), GFP_NOFS); |
| if (!ifp) { |
| kfree(fspath); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| ifp->btrfs_path = path; |
| ifp->fspath = fspath; |
| ifp->fs_root = fs_root; |
| |
| return ifp; |
| } |
| |
| void free_ipath(struct inode_fs_paths *ipath) |
| { |
| if (!ipath) |
| return; |
| vfree(ipath->fspath); |
| kfree(ipath); |
| } |