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|
- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2007,2008 Oracle. All rights reserved.
- */
- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/rbtree.h>
- #include <linux/mm.h>
- #include "ctree.h"
- #include "disk-io.h"
- #include "transaction.h"
- #include "print-tree.h"
- #include "locking.h"
- #include "volumes.h"
- #include "qgroup.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 void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
- int level, int slot);
- 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" },
- };
- int btrfs_super_csum_size(const struct btrfs_super_block *s)
- {
- u16 t = btrfs_super_csum_type(s);
- /*
- * csum type is validated at mount time
- */
- return btrfs_csums[t].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);
- }
- struct btrfs_path *btrfs_alloc_path(void)
- {
- return kmem_cache_zalloc(btrfs_path_cachep, GFP_NOFS);
- }
- /* this also releases the path */
- void btrfs_free_path(struct btrfs_path *p)
- {
- if (!p)
- return;
- btrfs_release_path(p);
- kmem_cache_free(btrfs_path_cachep, p);
- }
- /*
- * path release drops references on the extent buffers in the path
- * and it drops any locks held by this path
- *
- * It is safe to call this on paths that no locks or extent buffers held.
- */
- noinline void btrfs_release_path(struct btrfs_path *p)
- {
- int i;
- for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
- p->slots[i] = 0;
- if (!p->nodes[i])
- continue;
- if (p->locks[i]) {
- btrfs_tree_unlock_rw(p->nodes[i], p->locks[i]);
- p->locks[i] = 0;
- }
- free_extent_buffer(p->nodes[i]);
- p->nodes[i] = NULL;
- }
- }
- /*
- * safely gets a reference on the root node of a tree. A lock
- * is not taken, so a concurrent writer may put a different node
- * at the root of the tree. See btrfs_lock_root_node for the
- * looping required.
- *
- * The extent buffer returned by this has a reference taken, so
- * it won't disappear. It may stop being the root of the tree
- * at any time because there are no locks held.
- */
- struct extent_buffer *btrfs_root_node(struct btrfs_root *root)
- {
- struct extent_buffer *eb;
- while (1) {
- rcu_read_lock();
- eb = rcu_dereference(root->node);
- /*
- * RCU really hurts here, we could free up the root node because
- * it was COWed but we may not get the new root node yet so do
- * the inc_not_zero dance and if it doesn't work then
- * synchronize_rcu and try again.
- */
- if (atomic_inc_not_zero(&eb->refs)) {
- rcu_read_unlock();
- break;
- }
- rcu_read_unlock();
- synchronize_rcu();
- }
- return eb;
- }
- /*
- * Cowonly root (not-shareable trees, everything not subvolume or reloc roots),
- * just get put onto a simple dirty list. Transaction walks this list to make
- * sure they get properly updated on disk.
- */
- static void add_root_to_dirty_list(struct btrfs_root *root)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- if (test_bit(BTRFS_ROOT_DIRTY, &root->state) ||
- !test_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state))
- return;
- spin_lock(&fs_info->trans_lock);
- if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
- /* Want the extent tree to be the last on the list */
- if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID)
- list_move_tail(&root->dirty_list,
- &fs_info->dirty_cowonly_roots);
- else
- list_move(&root->dirty_list,
- &fs_info->dirty_cowonly_roots);
- }
- spin_unlock(&fs_info->trans_lock);
- }
- /*
- * used by snapshot creation to make a copy of a root for a tree with
- * a given objectid. The buffer with the new root node is returned in
- * cow_ret, and this func returns zero on success or a negative error code.
- */
- int btrfs_copy_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct extent_buffer *buf,
- struct extent_buffer **cow_ret, u64 new_root_objectid)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *cow;
- int ret = 0;
- int level;
- struct btrfs_disk_key disk_key;
- WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
- trans->transid != 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, new_root_objectid,
- &disk_key, level, buf->start, 0,
- BTRFS_NESTING_NEW_ROOT);
- 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 (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, fs_info->fs_devices->metadata_uuid);
- WARN_ON(btrfs_header_generation(buf) > trans->transid);
- if (new_root_objectid == BTRFS_TREE_RELOC_OBJECTID)
- ret = btrfs_inc_ref(trans, root, cow, 1);
- else
- ret = btrfs_inc_ref(trans, root, cow, 0);
- if (ret) {
- btrfs_tree_unlock(cow);
- free_extent_buffer(cow);
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- btrfs_mark_buffer_dirty(cow);
- *cow_ret = cow;
- return 0;
- }
- enum mod_log_op {
- MOD_LOG_KEY_REPLACE,
- MOD_LOG_KEY_ADD,
- MOD_LOG_KEY_REMOVE,
- MOD_LOG_KEY_REMOVE_WHILE_FREEING,
- MOD_LOG_KEY_REMOVE_WHILE_MOVING,
- MOD_LOG_MOVE_KEYS,
- MOD_LOG_ROOT_REPLACE,
- };
- struct tree_mod_root {
- u64 logical;
- u8 level;
- };
- struct tree_mod_elem {
- struct rb_node node;
- u64 logical;
- u64 seq;
- enum mod_log_op op;
- /* this is used for MOD_LOG_KEY_* and MOD_LOG_MOVE_KEYS operations */
- int slot;
- /* this is used for MOD_LOG_KEY* and MOD_LOG_ROOT_REPLACE */
- u64 generation;
- /* those are used for op == MOD_LOG_KEY_{REPLACE,REMOVE} */
- struct btrfs_disk_key key;
- u64 blockptr;
- /* this is used for op == MOD_LOG_MOVE_KEYS */
- struct {
- int dst_slot;
- int nr_items;
- } move;
- /* this is used for op == MOD_LOG_ROOT_REPLACE */
- struct tree_mod_root old_root;
- };
- /*
- * Pull a new tree mod seq number for our operation.
- */
- static inline u64 btrfs_inc_tree_mod_seq(struct btrfs_fs_info *fs_info)
- {
- return atomic64_inc_return(&fs_info->tree_mod_seq);
- }
- /*
- * This adds a new blocker to the tree mod log's blocker list if the @elem
- * passed does not already have a sequence number set. So when a caller expects
- * to record tree modifications, it should ensure to set elem->seq to zero
- * before calling btrfs_get_tree_mod_seq.
- * Returns a fresh, unused tree log modification sequence number, even if no new
- * blocker was added.
- */
- u64 btrfs_get_tree_mod_seq(struct btrfs_fs_info *fs_info,
- struct seq_list *elem)
- {
- write_lock(&fs_info->tree_mod_log_lock);
- if (!elem->seq) {
- elem->seq = btrfs_inc_tree_mod_seq(fs_info);
- list_add_tail(&elem->list, &fs_info->tree_mod_seq_list);
- }
- write_unlock(&fs_info->tree_mod_log_lock);
- return elem->seq;
- }
- void btrfs_put_tree_mod_seq(struct btrfs_fs_info *fs_info,
- struct seq_list *elem)
- {
- struct rb_root *tm_root;
- struct rb_node *node;
- struct rb_node *next;
- struct tree_mod_elem *tm;
- u64 min_seq = (u64)-1;
- u64 seq_putting = elem->seq;
- if (!seq_putting)
- return;
- write_lock(&fs_info->tree_mod_log_lock);
- list_del(&elem->list);
- elem->seq = 0;
- if (!list_empty(&fs_info->tree_mod_seq_list)) {
- struct seq_list *first;
- first = list_first_entry(&fs_info->tree_mod_seq_list,
- struct seq_list, list);
- if (seq_putting > first->seq) {
- /*
- * Blocker with lower sequence number exists, we
- * cannot remove anything from the log.
- */
- write_unlock(&fs_info->tree_mod_log_lock);
- return;
- }
- min_seq = first->seq;
- }
- /*
- * anything that's lower than the lowest existing (read: blocked)
- * sequence number can be removed from the tree.
- */
- tm_root = &fs_info->tree_mod_log;
- for (node = rb_first(tm_root); node; node = next) {
- next = rb_next(node);
- tm = rb_entry(node, struct tree_mod_elem, node);
- if (tm->seq >= min_seq)
- continue;
- rb_erase(node, tm_root);
- kfree(tm);
- }
- write_unlock(&fs_info->tree_mod_log_lock);
- }
- /*
- * key order of the log:
- * node/leaf start address -> sequence
- *
- * The 'start address' is the logical address of the *new* root node
- * for root replace operations, or the logical address of the affected
- * block for all other operations.
- */
- static noinline int
- __tree_mod_log_insert(struct btrfs_fs_info *fs_info, struct tree_mod_elem *tm)
- {
- struct rb_root *tm_root;
- struct rb_node **new;
- struct rb_node *parent = NULL;
- struct tree_mod_elem *cur;
- lockdep_assert_held_write(&fs_info->tree_mod_log_lock);
- tm->seq = btrfs_inc_tree_mod_seq(fs_info);
- tm_root = &fs_info->tree_mod_log;
- new = &tm_root->rb_node;
- while (*new) {
- cur = rb_entry(*new, struct tree_mod_elem, node);
- parent = *new;
- if (cur->logical < tm->logical)
- new = &((*new)->rb_left);
- else if (cur->logical > tm->logical)
- new = &((*new)->rb_right);
- else if (cur->seq < tm->seq)
- new = &((*new)->rb_left);
- else if (cur->seq > tm->seq)
- new = &((*new)->rb_right);
- else
- return -EEXIST;
- }
- rb_link_node(&tm->node, parent, new);
- rb_insert_color(&tm->node, tm_root);
- return 0;
- }
- /*
- * Determines if logging can be omitted. Returns 1 if it can. Otherwise, it
- * returns zero with the tree_mod_log_lock acquired. The caller must hold
- * this until all tree mod log insertions are recorded in the rb tree and then
- * write unlock fs_info::tree_mod_log_lock.
- */
- static inline int tree_mod_dont_log(struct btrfs_fs_info *fs_info,
- struct extent_buffer *eb) {
- smp_mb();
- if (list_empty(&(fs_info)->tree_mod_seq_list))
- return 1;
- if (eb && btrfs_header_level(eb) == 0)
- return 1;
- write_lock(&fs_info->tree_mod_log_lock);
- if (list_empty(&(fs_info)->tree_mod_seq_list)) {
- write_unlock(&fs_info->tree_mod_log_lock);
- return 1;
- }
- return 0;
- }
- /* Similar to tree_mod_dont_log, but doesn't acquire any locks. */
- static inline int tree_mod_need_log(const struct btrfs_fs_info *fs_info,
- struct extent_buffer *eb)
- {
- smp_mb();
- if (list_empty(&(fs_info)->tree_mod_seq_list))
- return 0;
- if (eb && btrfs_header_level(eb) == 0)
- return 0;
- return 1;
- }
- static struct tree_mod_elem *
- alloc_tree_mod_elem(struct extent_buffer *eb, int slot,
- enum mod_log_op op, gfp_t flags)
- {
- struct tree_mod_elem *tm;
- tm = kzalloc(sizeof(*tm), flags);
- if (!tm)
- return NULL;
- tm->logical = eb->start;
- if (op != MOD_LOG_KEY_ADD) {
- btrfs_node_key(eb, &tm->key, slot);
- tm->blockptr = btrfs_node_blockptr(eb, slot);
- }
- tm->op = op;
- tm->slot = slot;
- tm->generation = btrfs_node_ptr_generation(eb, slot);
- RB_CLEAR_NODE(&tm->node);
- return tm;
- }
- static noinline int tree_mod_log_insert_key(struct extent_buffer *eb, int slot,
- enum mod_log_op op, gfp_t flags)
- {
- struct tree_mod_elem *tm;
- int ret;
- if (!tree_mod_need_log(eb->fs_info, eb))
- return 0;
- tm = alloc_tree_mod_elem(eb, slot, op, flags);
- if (!tm)
- return -ENOMEM;
- if (tree_mod_dont_log(eb->fs_info, eb)) {
- kfree(tm);
- return 0;
- }
- ret = __tree_mod_log_insert(eb->fs_info, tm);
- write_unlock(&eb->fs_info->tree_mod_log_lock);
- if (ret)
- kfree(tm);
- return ret;
- }
- static noinline int tree_mod_log_insert_move(struct extent_buffer *eb,
- int dst_slot, int src_slot, int nr_items)
- {
- struct tree_mod_elem *tm = NULL;
- struct tree_mod_elem **tm_list = NULL;
- int ret = 0;
- int i;
- int locked = 0;
- if (!tree_mod_need_log(eb->fs_info, eb))
- return 0;
- tm_list = kcalloc(nr_items, sizeof(struct tree_mod_elem *), GFP_NOFS);
- if (!tm_list)
- return -ENOMEM;
- tm = kzalloc(sizeof(*tm), GFP_NOFS);
- if (!tm) {
- ret = -ENOMEM;
- goto free_tms;
- }
- tm->logical = eb->start;
- tm->slot = src_slot;
- tm->move.dst_slot = dst_slot;
- tm->move.nr_items = nr_items;
- tm->op = MOD_LOG_MOVE_KEYS;
- for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
- tm_list[i] = alloc_tree_mod_elem(eb, i + dst_slot,
- MOD_LOG_KEY_REMOVE_WHILE_MOVING, GFP_NOFS);
- if (!tm_list[i]) {
- ret = -ENOMEM;
- goto free_tms;
- }
- }
- if (tree_mod_dont_log(eb->fs_info, eb))
- goto free_tms;
- locked = 1;
- /*
- * When we override something during the move, we log these removals.
- * This can only happen when we move towards the beginning of the
- * buffer, i.e. dst_slot < src_slot.
- */
- for (i = 0; i + dst_slot < src_slot && i < nr_items; i++) {
- ret = __tree_mod_log_insert(eb->fs_info, tm_list[i]);
- if (ret)
- goto free_tms;
- }
- ret = __tree_mod_log_insert(eb->fs_info, tm);
- if (ret)
- goto free_tms;
- write_unlock(&eb->fs_info->tree_mod_log_lock);
- kfree(tm_list);
- return 0;
- free_tms:
- for (i = 0; i < nr_items; i++) {
- if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
- rb_erase(&tm_list[i]->node, &eb->fs_info->tree_mod_log);
- kfree(tm_list[i]);
- }
- if (locked)
- write_unlock(&eb->fs_info->tree_mod_log_lock);
- kfree(tm_list);
- kfree(tm);
- return ret;
- }
- static inline int
- __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info,
- struct tree_mod_elem **tm_list,
- int nritems)
- {
- int i, j;
- int ret;
- for (i = nritems - 1; i >= 0; i--) {
- ret = __tree_mod_log_insert(fs_info, tm_list[i]);
- if (ret) {
- for (j = nritems - 1; j > i; j--)
- rb_erase(&tm_list[j]->node,
- &fs_info->tree_mod_log);
- return ret;
- }
- }
- return 0;
- }
- static noinline int tree_mod_log_insert_root(struct extent_buffer *old_root,
- struct extent_buffer *new_root, int log_removal)
- {
- struct btrfs_fs_info *fs_info = old_root->fs_info;
- struct tree_mod_elem *tm = NULL;
- struct tree_mod_elem **tm_list = NULL;
- int nritems = 0;
- int ret = 0;
- int i;
- if (!tree_mod_need_log(fs_info, NULL))
- return 0;
- if (log_removal && btrfs_header_level(old_root) > 0) {
- nritems = btrfs_header_nritems(old_root);
- tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *),
- GFP_NOFS);
- if (!tm_list) {
- ret = -ENOMEM;
- goto free_tms;
- }
- for (i = 0; i < nritems; i++) {
- tm_list[i] = alloc_tree_mod_elem(old_root, i,
- MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS);
- if (!tm_list[i]) {
- ret = -ENOMEM;
- goto free_tms;
- }
- }
- }
- tm = kzalloc(sizeof(*tm), GFP_NOFS);
- if (!tm) {
- ret = -ENOMEM;
- goto free_tms;
- }
- tm->logical = new_root->start;
- tm->old_root.logical = old_root->start;
- tm->old_root.level = btrfs_header_level(old_root);
- tm->generation = btrfs_header_generation(old_root);
- tm->op = MOD_LOG_ROOT_REPLACE;
- if (tree_mod_dont_log(fs_info, NULL))
- goto free_tms;
- if (tm_list)
- ret = __tree_mod_log_free_eb(fs_info, tm_list, nritems);
- if (!ret)
- ret = __tree_mod_log_insert(fs_info, tm);
- write_unlock(&fs_info->tree_mod_log_lock);
- if (ret)
- goto free_tms;
- kfree(tm_list);
- return ret;
- free_tms:
- if (tm_list) {
- for (i = 0; i < nritems; i++)
- kfree(tm_list[i]);
- kfree(tm_list);
- }
- kfree(tm);
- return ret;
- }
- static struct tree_mod_elem *
- __tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq,
- int smallest)
- {
- struct rb_root *tm_root;
- struct rb_node *node;
- struct tree_mod_elem *cur = NULL;
- struct tree_mod_elem *found = NULL;
- read_lock(&fs_info->tree_mod_log_lock);
- tm_root = &fs_info->tree_mod_log;
- node = tm_root->rb_node;
- while (node) {
- cur = rb_entry(node, struct tree_mod_elem, node);
- if (cur->logical < start) {
- node = node->rb_left;
- } else if (cur->logical > start) {
- node = node->rb_right;
- } else if (cur->seq < min_seq) {
- node = node->rb_left;
- } else if (!smallest) {
- /* we want the node with the highest seq */
- if (found)
- BUG_ON(found->seq > cur->seq);
- found = cur;
- node = node->rb_left;
- } else if (cur->seq > min_seq) {
- /* we want the node with the smallest seq */
- if (found)
- BUG_ON(found->seq < cur->seq);
- found = cur;
- node = node->rb_right;
- } else {
- found = cur;
- break;
- }
- }
- read_unlock(&fs_info->tree_mod_log_lock);
- return found;
- }
- /*
- * this returns the element from the log with the smallest time sequence
- * value that's in the log (the oldest log item). any element with a time
- * sequence lower than min_seq will be ignored.
- */
- static struct tree_mod_elem *
- tree_mod_log_search_oldest(struct btrfs_fs_info *fs_info, u64 start,
- u64 min_seq)
- {
- return __tree_mod_log_search(fs_info, start, min_seq, 1);
- }
- /*
- * this returns the element from the log with the largest time sequence
- * value that's in the log (the most recent log item). any element with
- * a time sequence lower than min_seq will be ignored.
- */
- static struct tree_mod_elem *
- tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
- {
- return __tree_mod_log_search(fs_info, start, min_seq, 0);
- }
- static noinline int tree_mod_log_eb_copy(struct extent_buffer *dst,
- struct extent_buffer *src, unsigned long dst_offset,
- unsigned long src_offset, int nr_items)
- {
- struct btrfs_fs_info *fs_info = dst->fs_info;
- int ret = 0;
- struct tree_mod_elem **tm_list = NULL;
- struct tree_mod_elem **tm_list_add, **tm_list_rem;
- int i;
- int locked = 0;
- if (!tree_mod_need_log(fs_info, NULL))
- return 0;
- if (btrfs_header_level(dst) == 0 && btrfs_header_level(src) == 0)
- return 0;
- tm_list = kcalloc(nr_items * 2, sizeof(struct tree_mod_elem *),
- GFP_NOFS);
- if (!tm_list)
- return -ENOMEM;
- tm_list_add = tm_list;
- tm_list_rem = tm_list + nr_items;
- for (i = 0; i < nr_items; i++) {
- tm_list_rem[i] = alloc_tree_mod_elem(src, i + src_offset,
- MOD_LOG_KEY_REMOVE, GFP_NOFS);
- if (!tm_list_rem[i]) {
- ret = -ENOMEM;
- goto free_tms;
- }
- tm_list_add[i] = alloc_tree_mod_elem(dst, i + dst_offset,
- MOD_LOG_KEY_ADD, GFP_NOFS);
- if (!tm_list_add[i]) {
- ret = -ENOMEM;
- goto free_tms;
- }
- }
- if (tree_mod_dont_log(fs_info, NULL))
- goto free_tms;
- locked = 1;
- for (i = 0; i < nr_items; i++) {
- ret = __tree_mod_log_insert(fs_info, tm_list_rem[i]);
- if (ret)
- goto free_tms;
- ret = __tree_mod_log_insert(fs_info, tm_list_add[i]);
- if (ret)
- goto free_tms;
- }
- write_unlock(&fs_info->tree_mod_log_lock);
- kfree(tm_list);
- return 0;
- free_tms:
- for (i = 0; i < nr_items * 2; i++) {
- if (tm_list[i] && !RB_EMPTY_NODE(&tm_list[i]->node))
- rb_erase(&tm_list[i]->node, &fs_info->tree_mod_log);
- kfree(tm_list[i]);
- }
- if (locked)
- write_unlock(&fs_info->tree_mod_log_lock);
- kfree(tm_list);
- return ret;
- }
- static noinline int tree_mod_log_free_eb(struct extent_buffer *eb)
- {
- struct tree_mod_elem **tm_list = NULL;
- int nritems = 0;
- int i;
- int ret = 0;
- if (btrfs_header_level(eb) == 0)
- return 0;
- if (!tree_mod_need_log(eb->fs_info, NULL))
- return 0;
- nritems = btrfs_header_nritems(eb);
- tm_list = kcalloc(nritems, sizeof(struct tree_mod_elem *), GFP_NOFS);
- if (!tm_list)
- return -ENOMEM;
- for (i = 0; i < nritems; i++) {
- tm_list[i] = alloc_tree_mod_elem(eb, i,
- MOD_LOG_KEY_REMOVE_WHILE_FREEING, GFP_NOFS);
- if (!tm_list[i]) {
- ret = -ENOMEM;
- goto free_tms;
- }
- }
- if (tree_mod_dont_log(eb->fs_info, eb))
- goto free_tms;
- ret = __tree_mod_log_free_eb(eb->fs_info, tm_list, nritems);
- write_unlock(&eb->fs_info->tree_mod_log_lock);
- if (ret)
- goto free_tms;
- kfree(tm_list);
- return 0;
- free_tms:
- for (i = 0; i < nritems; i++)
- kfree(tm_list[i]);
- kfree(tm_list);
- return ret;
- }
- /*
- * check if the tree block can be shared by multiple trees
- */
- int btrfs_block_can_be_shared(struct btrfs_root *root,
- struct extent_buffer *buf)
- {
- /*
- * Tree blocks not in 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,
- int *last_ref)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- 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, fs_info, buf->start,
- btrfs_header_level(buf), 1,
- &refs, &flags);
- if (ret)
- return ret;
- if (refs == 0) {
- ret = -EROFS;
- btrfs_handle_fs_error(fs_info, ret, NULL);
- return ret;
- }
- } else {
- refs = 1;
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
- btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
- flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
- else
- flags = 0;
- }
- owner = btrfs_header_owner(buf);
- BUG_ON(owner == BTRFS_TREE_RELOC_OBJECTID &&
- !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
- if (refs > 1) {
- if ((owner == root->root_key.objectid ||
- root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) &&
- !(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)) {
- ret = btrfs_inc_ref(trans, root, buf, 1);
- if (ret)
- return ret;
- if (root->root_key.objectid ==
- BTRFS_TREE_RELOC_OBJECTID) {
- ret = btrfs_dec_ref(trans, root, buf, 0);
- if (ret)
- return ret;
- ret = btrfs_inc_ref(trans, root, cow, 1);
- if (ret)
- return 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);
- if (ret)
- return ret;
- }
- if (new_flags != 0) {
- int level = btrfs_header_level(buf);
- ret = btrfs_set_disk_extent_flags(trans, buf,
- new_flags, level, 0);
- if (ret)
- return ret;
- }
- } else {
- if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
- if (root->root_key.objectid ==
- BTRFS_TREE_RELOC_OBJECTID)
- ret = btrfs_inc_ref(trans, root, cow, 1);
- else
- ret = btrfs_inc_ref(trans, root, cow, 0);
- if (ret)
- return ret;
- ret = btrfs_dec_ref(trans, root, buf, 1);
- if (ret)
- return ret;
- }
- btrfs_clean_tree_block(buf);
- *last_ref = 1;
- }
- return 0;
- }
- static struct extent_buffer *alloc_tree_block_no_bg_flush(
- struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- u64 parent_start,
- const struct btrfs_disk_key *disk_key,
- int level,
- u64 hint,
- u64 empty_size,
- enum btrfs_lock_nesting nest)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *ret;
- /*
- * If we are COWing a node/leaf from the extent, chunk, device or free
- * space trees, make sure that we do not finish block group creation of
- * pending block groups. We do this to avoid a deadlock.
- * COWing can result in allocation of a new chunk, and flushing pending
- * block groups (btrfs_create_pending_block_groups()) can be triggered
- * when finishing allocation of a new chunk. Creation of a pending block
- * group modifies the extent, chunk, device and free space trees,
- * therefore we could deadlock with ourselves since we are holding a
- * lock on an extent buffer that btrfs_create_pending_block_groups() may
- * try to COW later.
- * For similar reasons, we also need to delay flushing pending block
- * groups when splitting a leaf or node, from one of those trees, since
- * we are holding a write lock on it and its parent or when inserting a
- * new root node for one of those trees.
- */
- if (root == fs_info->extent_root ||
- root == fs_info->chunk_root ||
- root == fs_info->dev_root ||
- root == fs_info->free_space_root)
- trans->can_flush_pending_bgs = false;
- ret = btrfs_alloc_tree_block(trans, root, parent_start,
- root->root_key.objectid, disk_key, level,
- hint, empty_size, nest);
- trans->can_flush_pending_bgs = true;
- return ret;
- }
- /*
- * 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,
- enum btrfs_lock_nesting nest)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_disk_key disk_key;
- struct extent_buffer *cow;
- int level, ret;
- int last_ref = 0;
- int unlock_orig = 0;
- u64 parent_start = 0;
- if (*cow_ret == buf)
- unlock_orig = 1;
- btrfs_assert_tree_locked(buf);
- WARN_ON(test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
- trans->transid != 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);
- if ((root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) && parent)
- parent_start = parent->start;
- cow = alloc_tree_block_no_bg_flush(trans, root, parent_start, &disk_key,
- level, search_start, empty_size, nest);
- if (IS_ERR(cow))
- return PTR_ERR(cow);
- /* cow is set to blocking by btrfs_init_new_buffer */
- 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, fs_info->fs_devices->metadata_uuid);
- ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
- if (ret) {
- btrfs_tree_unlock(cow);
- free_extent_buffer(cow);
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
- ret = btrfs_reloc_cow_block(trans, root, buf, cow);
- if (ret) {
- btrfs_tree_unlock(cow);
- free_extent_buffer(cow);
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- }
- if (buf == root->node) {
- WARN_ON(parent && parent != buf);
- if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
- btrfs_header_backref_rev(buf) < BTRFS_MIXED_BACKREF_REV)
- parent_start = buf->start;
- atomic_inc(&cow->refs);
- ret = tree_mod_log_insert_root(root->node, cow, 1);
- BUG_ON(ret < 0);
- rcu_assign_pointer(root->node, cow);
- btrfs_free_tree_block(trans, root, buf, parent_start,
- last_ref);
- free_extent_buffer(buf);
- add_root_to_dirty_list(root);
- } else {
- WARN_ON(trans->transid != btrfs_header_generation(parent));
- tree_mod_log_insert_key(parent, parent_slot,
- MOD_LOG_KEY_REPLACE, GFP_NOFS);
- btrfs_set_node_blockptr(parent, parent_slot,
- cow->start);
- btrfs_set_node_ptr_generation(parent, parent_slot,
- trans->transid);
- btrfs_mark_buffer_dirty(parent);
- if (last_ref) {
- ret = tree_mod_log_free_eb(buf);
- if (ret) {
- btrfs_tree_unlock(cow);
- free_extent_buffer(cow);
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- }
- btrfs_free_tree_block(trans, root, buf, parent_start,
- last_ref);
- }
- if (unlock_orig)
- btrfs_tree_unlock(buf);
- free_extent_buffer_stale(buf);
- btrfs_mark_buffer_dirty(cow);
- *cow_ret = cow;
- return 0;
- }
- /*
- * returns the logical address of the oldest predecessor of the given root.
- * entries older than time_seq are ignored.
- */
- static struct tree_mod_elem *__tree_mod_log_oldest_root(
- struct extent_buffer *eb_root, u64 time_seq)
- {
- struct tree_mod_elem *tm;
- struct tree_mod_elem *found = NULL;
- u64 root_logical = eb_root->start;
- int looped = 0;
- if (!time_seq)
- return NULL;
- /*
- * the very last operation that's logged for a root is the
- * replacement operation (if it is replaced at all). this has
- * the logical address of the *new* root, making it the very
- * first operation that's logged for this root.
- */
- while (1) {
- tm = tree_mod_log_search_oldest(eb_root->fs_info, root_logical,
- time_seq);
- if (!looped && !tm)
- return NULL;
- /*
- * if there are no tree operation for the oldest root, we simply
- * return it. this should only happen if that (old) root is at
- * level 0.
- */
- if (!tm)
- break;
- /*
- * if there's an operation that's not a root replacement, we
- * found the oldest version of our root. normally, we'll find a
- * MOD_LOG_KEY_REMOVE_WHILE_FREEING operation here.
- */
- if (tm->op != MOD_LOG_ROOT_REPLACE)
- break;
- found = tm;
- root_logical = tm->old_root.logical;
- looped = 1;
- }
- /* if there's no old root to return, return what we found instead */
- if (!found)
- found = tm;
- return found;
- }
- /*
- * tm is a pointer to the first operation to rewind within eb. then, all
- * previous operations will be rewound (until we reach something older than
- * time_seq).
- */
- static void
- __tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
- u64 time_seq, struct tree_mod_elem *first_tm)
- {
- u32 n;
- struct rb_node *next;
- struct tree_mod_elem *tm = first_tm;
- unsigned long o_dst;
- unsigned long o_src;
- unsigned long p_size = sizeof(struct btrfs_key_ptr);
- n = btrfs_header_nritems(eb);
- read_lock(&fs_info->tree_mod_log_lock);
- while (tm && tm->seq >= time_seq) {
- /*
- * all the operations are recorded with the operator used for
- * the modification. as we're going backwards, we do the
- * opposite of each operation here.
- */
- switch (tm->op) {
- case MOD_LOG_KEY_REMOVE_WHILE_FREEING:
- BUG_ON(tm->slot < n);
- fallthrough;
- case MOD_LOG_KEY_REMOVE_WHILE_MOVING:
- case MOD_LOG_KEY_REMOVE:
- btrfs_set_node_key(eb, &tm->key, tm->slot);
- btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
- btrfs_set_node_ptr_generation(eb, tm->slot,
- tm->generation);
- n++;
- break;
- case MOD_LOG_KEY_REPLACE:
- BUG_ON(tm->slot >= n);
- btrfs_set_node_key(eb, &tm->key, tm->slot);
- btrfs_set_node_blockptr(eb, tm->slot, tm->blockptr);
- btrfs_set_node_ptr_generation(eb, tm->slot,
- tm->generation);
- break;
- case MOD_LOG_KEY_ADD:
- /* if a move operation is needed it's in the log */
- n--;
- break;
- case MOD_LOG_MOVE_KEYS:
- o_dst = btrfs_node_key_ptr_offset(tm->slot);
- o_src = btrfs_node_key_ptr_offset(tm->move.dst_slot);
- memmove_extent_buffer(eb, o_dst, o_src,
- tm->move.nr_items * p_size);
- break;
- case MOD_LOG_ROOT_REPLACE:
- /*
- * this operation is special. for roots, this must be
- * handled explicitly before rewinding.
- * for non-roots, this operation may exist if the node
- * was a root: root A -> child B; then A gets empty and
- * B is promoted to the new root. in the mod log, we'll
- * have a root-replace operation for B, a tree block
- * that is no root. we simply ignore that operation.
- */
- break;
- }
- next = rb_next(&tm->node);
- if (!next)
- break;
- tm = rb_entry(next, struct tree_mod_elem, node);
- if (tm->logical != first_tm->logical)
- break;
- }
- read_unlock(&fs_info->tree_mod_log_lock);
- btrfs_set_header_nritems(eb, n);
- }
- /*
- * Called with eb read locked. If the buffer cannot be rewound, the same buffer
- * is returned. If rewind operations happen, a fresh buffer is returned. The
- * returned buffer is always read-locked. If the returned buffer is not the
- * input buffer, the lock on the input buffer is released and the input buffer
- * is freed (its refcount is decremented).
- */
- static struct extent_buffer *
- tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct btrfs_path *path,
- struct extent_buffer *eb, u64 time_seq)
- {
- struct extent_buffer *eb_rewin;
- struct tree_mod_elem *tm;
- if (!time_seq)
- return eb;
- if (btrfs_header_level(eb) == 0)
- return eb;
- tm = tree_mod_log_search(fs_info, eb->start, time_seq);
- if (!tm)
- return eb;
- btrfs_set_path_blocking(path);
- btrfs_set_lock_blocking_read(eb);
- if (tm->op == MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
- BUG_ON(tm->slot != 0);
- eb_rewin = alloc_dummy_extent_buffer(fs_info, eb->start);
- if (!eb_rewin) {
- btrfs_tree_read_unlock_blocking(eb);
- free_extent_buffer(eb);
- return NULL;
- }
- btrfs_set_header_bytenr(eb_rewin, eb->start);
- btrfs_set_header_backref_rev(eb_rewin,
- btrfs_header_backref_rev(eb));
- btrfs_set_header_owner(eb_rewin, btrfs_header_owner(eb));
- btrfs_set_header_level(eb_rewin, btrfs_header_level(eb));
- } else {
- eb_rewin = btrfs_clone_extent_buffer(eb);
- if (!eb_rewin) {
- btrfs_tree_read_unlock_blocking(eb);
- free_extent_buffer(eb);
- return NULL;
- }
- }
- btrfs_tree_read_unlock_blocking(eb);
- free_extent_buffer(eb);
- btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb_rewin),
- eb_rewin, btrfs_header_level(eb_rewin));
- btrfs_tree_read_lock(eb_rewin);
- __tree_mod_log_rewind(fs_info, eb_rewin, time_seq, tm);
- WARN_ON(btrfs_header_nritems(eb_rewin) >
- BTRFS_NODEPTRS_PER_BLOCK(fs_info));
- return eb_rewin;
- }
- /*
- * get_old_root() rewinds the state of @root's root node to the given @time_seq
- * value. If there are no changes, the current root->root_node is returned. If
- * anything changed in between, there's a fresh buffer allocated on which the
- * rewind operations are done. In any case, the returned buffer is read locked.
- * Returns NULL on error (with no locks held).
- */
- static inline struct extent_buffer *
- get_old_root(struct btrfs_root *root, u64 time_seq)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct tree_mod_elem *tm;
- struct extent_buffer *eb = NULL;
- struct extent_buffer *eb_root;
- u64 eb_root_owner = 0;
- struct extent_buffer *old;
- struct tree_mod_root *old_root = NULL;
- u64 old_generation = 0;
- u64 logical;
- int level;
- eb_root = btrfs_read_lock_root_node(root);
- tm = __tree_mod_log_oldest_root(eb_root, time_seq);
- if (!tm)
- return eb_root;
- if (tm->op == MOD_LOG_ROOT_REPLACE) {
- old_root = &tm->old_root;
- old_generation = tm->generation;
- logical = old_root->logical;
- level = old_root->level;
- } else {
- logical = eb_root->start;
- level = btrfs_header_level(eb_root);
- }
- tm = tree_mod_log_search(fs_info, logical, time_seq);
- if (old_root && tm && tm->op != MOD_LOG_KEY_REMOVE_WHILE_FREEING) {
- btrfs_tree_read_unlock(eb_root);
- free_extent_buffer(eb_root);
- old = read_tree_block(fs_info, logical, 0, level, NULL);
- if (WARN_ON(IS_ERR(old) || !extent_buffer_uptodate(old))) {
- if (!IS_ERR(old))
- free_extent_buffer(old);
- btrfs_warn(fs_info,
- "failed to read tree block %llu from get_old_root",
- logical);
- } else {
- struct tree_mod_elem *tm2;
- btrfs_tree_read_lock(old);
- eb = btrfs_clone_extent_buffer(old);
- /*
- * After the lookup for the most recent tree mod operation
- * above and before we locked and cloned the extent buffer
- * 'old', a new tree mod log operation may have been added.
- * So lookup for a more recent one to make sure the number
- * of mod log operations we replay is consistent with the
- * number of items we have in the cloned extent buffer,
- * otherwise we can hit a BUG_ON when rewinding the extent
- * buffer.
- */
- tm2 = tree_mod_log_search(fs_info, logical, time_seq);
- btrfs_tree_read_unlock(old);
- free_extent_buffer(old);
- ASSERT(tm2);
- ASSERT(tm2 == tm || tm2->seq > tm->seq);
- if (!tm2 || tm2->seq < tm->seq) {
- free_extent_buffer(eb);
- return NULL;
- }
- tm = tm2;
- }
- } else if (old_root) {
- eb_root_owner = btrfs_header_owner(eb_root);
- btrfs_tree_read_unlock(eb_root);
- free_extent_buffer(eb_root);
- eb = alloc_dummy_extent_buffer(fs_info, logical);
- } else {
- btrfs_set_lock_blocking_read(eb_root);
- eb = btrfs_clone_extent_buffer(eb_root);
- btrfs_tree_read_unlock_blocking(eb_root);
- free_extent_buffer(eb_root);
- }
- if (!eb)
- return NULL;
- if (old_root) {
- btrfs_set_header_bytenr(eb, eb->start);
- btrfs_set_header_backref_rev(eb, BTRFS_MIXED_BACKREF_REV);
- btrfs_set_header_owner(eb, eb_root_owner);
- btrfs_set_header_level(eb, old_root->level);
- btrfs_set_header_generation(eb, old_generation);
- }
- btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb), eb,
- btrfs_header_level(eb));
- btrfs_tree_read_lock(eb);
- if (tm)
- __tree_mod_log_rewind(fs_info, eb, time_seq, tm);
- else
- WARN_ON(btrfs_header_level(eb) != 0);
- WARN_ON(btrfs_header_nritems(eb) > BTRFS_NODEPTRS_PER_BLOCK(fs_info));
- return eb;
- }
- int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq)
- {
- struct tree_mod_elem *tm;
- int level;
- struct extent_buffer *eb_root = btrfs_root_node(root);
- tm = __tree_mod_log_oldest_root(eb_root, time_seq);
- if (tm && tm->op == MOD_LOG_ROOT_REPLACE) {
- level = tm->old_root.level;
- } else {
- level = btrfs_header_level(eb_root);
- }
- free_extent_buffer(eb_root);
- return level;
- }
- static inline int should_cow_block(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct extent_buffer *buf)
- {
- if (btrfs_is_testing(root->fs_info))
- return 0;
- /* Ensure we can see the FORCE_COW bit */
- smp_mb__before_atomic();
- /*
- * We do not need to cow a block if
- * 1) this block is not created or changed in this transaction;
- * 2) this block does not belong to TREE_RELOC tree;
- * 3) the root is not forced COW.
- *
- * What is forced COW:
- * when we create snapshot during committing the transaction,
- * after we've finished copying src root, we must COW the shared
- * block to ensure the metadata consistency.
- */
- if (btrfs_header_generation(buf) == trans->transid &&
- !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN) &&
- !(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
- btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC)) &&
- !test_bit(BTRFS_ROOT_FORCE_COW, &root->state))
- return 0;
- return 1;
- }
- /*
- * cows a single block, see __btrfs_cow_block for the real work.
- * This version of it has extra checks so that a block isn't COWed more than
- * once per transaction, as long as it hasn't been written yet
- */
- noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct extent_buffer *buf,
- struct extent_buffer *parent, int parent_slot,
- struct extent_buffer **cow_ret,
- enum btrfs_lock_nesting nest)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- u64 search_start;
- int ret;
- if (test_bit(BTRFS_ROOT_DELETING, &root->state))
- btrfs_err(fs_info,
- "COW'ing blocks on a fs root that's being dropped");
- if (trans->transaction != fs_info->running_transaction)
- WARN(1, KERN_CRIT "trans %llu running %llu\n",
- trans->transid,
- fs_info->running_transaction->transid);
- if (trans->transid != fs_info->generation)
- WARN(1, KERN_CRIT "trans %llu running %llu\n",
- trans->transid, fs_info->generation);
- if (!should_cow_block(trans, root, buf)) {
- trans->dirty = true;
- *cow_ret = buf;
- return 0;
- }
- search_start = buf->start & ~((u64)SZ_1G - 1);
- if (parent)
- btrfs_set_lock_blocking_write(parent);
- btrfs_set_lock_blocking_write(buf);
- /*
- * Before CoWing this block for later modification, check if it's
- * the subtree root and do the delayed subtree trace if needed.
- *
- * Also We don't care about the error, as it's handled internally.
- */
- btrfs_qgroup_trace_subtree_after_cow(trans, root, buf);
- ret = __btrfs_cow_block(trans, root, buf, parent,
- parent_slot, cow_ret, search_start, 0, nest);
- trace_btrfs_cow_block(root, buf, *cow_ret);
- return ret;
- }
- /*
- * helper function for defrag to decide if two blocks pointed to by a
- * node are actually close by
- */
- static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
- {
- if (blocknr < other && other - (blocknr + blocksize) < 32768)
- return 1;
- if (blocknr > other && blocknr - (other + blocksize) < 32768)
- return 1;
- return 0;
- }
- #ifdef __LITTLE_ENDIAN
- /*
- * Compare two keys, on little-endian the disk order is same as CPU order and
- * we can avoid the conversion.
- */
- static int comp_keys(const struct btrfs_disk_key *disk_key,
- const struct btrfs_key *k2)
- {
- const struct btrfs_key *k1 = (const struct btrfs_key *)disk_key;
- return btrfs_comp_cpu_keys(k1, k2);
- }
- #else
- /*
- * compare two keys in a memcmp fashion
- */
- static int comp_keys(const 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);
- }
- #endif
- /*
- * 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;
- }
- /*
- * this is used by the defrag code to go through all the
- * leaves pointed to by a node and reallocate them so that
- * disk order is close to key order
- */
- int btrfs_realloc_node(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct extent_buffer *parent,
- int start_slot, u64 *last_ret,
- struct btrfs_key *progress)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *cur;
- u64 blocknr;
- u64 gen;
- u64 search_start = *last_ret;
- u64 last_block = 0;
- u64 other;
- u32 parent_nritems;
- int end_slot;
- int i;
- int err = 0;
- int parent_level;
- int uptodate;
- u32 blocksize;
- int progress_passed = 0;
- struct btrfs_disk_key disk_key;
- parent_level = btrfs_header_level(parent);
- WARN_ON(trans->transaction != fs_info->running_transaction);
- WARN_ON(trans->transid != fs_info->generation);
- parent_nritems = btrfs_header_nritems(parent);
- blocksize = fs_info->nodesize;
- end_slot = parent_nritems - 1;
- if (parent_nritems <= 1)
- return 0;
- btrfs_set_lock_blocking_write(parent);
- for (i = start_slot; i <= end_slot; i++) {
- struct btrfs_key first_key;
- int close = 1;
- btrfs_node_key(parent, &disk_key, i);
- if (!progress_passed && comp_keys(&disk_key, progress) < 0)
- continue;
- progress_passed = 1;
- blocknr = btrfs_node_blockptr(parent, i);
- gen = btrfs_node_ptr_generation(parent, i);
- btrfs_node_key_to_cpu(parent, &first_key, i);
- if (last_block == 0)
- last_block = blocknr;
- if (i > 0) {
- other = btrfs_node_blockptr(parent, i - 1);
- close = close_blocks(blocknr, other, blocksize);
- }
- if (!close && i < end_slot) {
- other = btrfs_node_blockptr(parent, i + 1);
- close = close_blocks(blocknr, other, blocksize);
- }
- if (close) {
- last_block = blocknr;
- continue;
- }
- cur = find_extent_buffer(fs_info, blocknr);
- if (cur)
- uptodate = btrfs_buffer_uptodate(cur, gen, 0);
- else
- uptodate = 0;
- if (!cur || !uptodate) {
- if (!cur) {
- cur = read_tree_block(fs_info, blocknr, gen,
- parent_level - 1,
- &first_key);
- if (IS_ERR(cur)) {
- return PTR_ERR(cur);
- } else if (!extent_buffer_uptodate(cur)) {
- free_extent_buffer(cur);
- return -EIO;
- }
- } else if (!uptodate) {
- err = btrfs_read_buffer(cur, gen,
- parent_level - 1,&first_key);
- if (err) {
- free_extent_buffer(cur);
- return err;
- }
- }
- }
- if (search_start == 0)
- search_start = last_block;
- btrfs_tree_lock(cur);
- btrfs_set_lock_blocking_write(cur);
- err = __btrfs_cow_block(trans, root, cur, parent, i,
- &cur, search_start,
- min(16 * blocksize,
- (end_slot - i) * blocksize),
- BTRFS_NESTING_COW);
- if (err) {
- btrfs_tree_unlock(cur);
- free_extent_buffer(cur);
- break;
- }
- search_start = cur->start;
- last_block = cur->start;
- *last_ret = search_start;
- btrfs_tree_unlock(cur);
- free_extent_buffer(cur);
- }
- return err;
- }
- /*
- * search for key in the extent_buffer. The items start at offset p,
- * and they are item_size apart. There are 'max' items in p.
- *
- * the slot in the array is returned via slot, and it points to
- * the place where you would insert key if it is not found in
- * the array.
- *
- * slot may point to max if the key is bigger than all of the keys
- */
- static noinline int generic_bin_search(struct extent_buffer *eb,
- unsigned long p, int item_size,
- const struct btrfs_key *key,
- int max, int *slot)
- {
- int low = 0;
- int high = max;
- int ret;
- const int key_size = sizeof(struct btrfs_disk_key);
- if (low > high) {
- btrfs_err(eb->fs_info,
- "%s: low (%d) > high (%d) eb %llu owner %llu level %d",
- __func__, low, high, eb->start,
- btrfs_header_owner(eb), btrfs_header_level(eb));
- return -EINVAL;
- }
- while (low < high) {
- unsigned long oip;
- unsigned long offset;
- struct btrfs_disk_key *tmp;
- struct btrfs_disk_key unaligned;
- int mid;
- mid = (low + high) / 2;
- offset = p + mid * item_size;
- oip = offset_in_page(offset);
- if (oip + key_size <= PAGE_SIZE) {
- const unsigned long idx = offset >> PAGE_SHIFT;
- char *kaddr = page_address(eb->pages[idx]);
- tmp = (struct btrfs_disk_key *)(kaddr + oip);
- } else {
- read_extent_buffer(eb, &unaligned, offset, key_size);
- tmp = &unaligned;
- }
- ret = comp_keys(tmp, key);
- if (ret < 0)
- low = mid + 1;
- else if (ret > 0)
- high = mid;
- else {
- *slot = mid;
- return 0;
- }
- }
- *slot = low;
- return 1;
- }
- /*
- * simple bin_search frontend that does the right thing for
- * leaves vs nodes
- */
- int btrfs_bin_search(struct extent_buffer *eb, 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);
- }
- static void root_add_used(struct btrfs_root *root, u32 size)
- {
- spin_lock(&root->accounting_lock);
- btrfs_set_root_used(&root->root_item,
- btrfs_root_used(&root->root_item) + size);
- spin_unlock(&root->accounting_lock);
- }
- static void root_sub_used(struct btrfs_root *root, u32 size)
- {
- spin_lock(&root->accounting_lock);
- btrfs_set_root_used(&root->root_item,
- btrfs_root_used(&root->root_item) - size);
- spin_unlock(&root->accounting_lock);
- }
- /* given a node and slot number, this reads the blocks it points to. The
- * extent buffer is returned with a reference taken (but unlocked).
- */
- struct extent_buffer *btrfs_read_node_slot(struct extent_buffer *parent,
- int slot)
- {
- int level = btrfs_header_level(parent);
- struct extent_buffer *eb;
- struct btrfs_key first_key;
- if (slot < 0 || slot >= btrfs_header_nritems(parent))
- return ERR_PTR(-ENOENT);
- BUG_ON(level == 0);
- btrfs_node_key_to_cpu(parent, &first_key, slot);
- eb = read_tree_block(parent->fs_info, btrfs_node_blockptr(parent, slot),
- btrfs_node_ptr_generation(parent, slot),
- level - 1, &first_key);
- if (!IS_ERR(eb) && !extent_buffer_uptodate(eb)) {
- free_extent_buffer(eb);
- eb = ERR_PTR(-EIO);
- }
- return eb;
- }
- /*
- * 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;
- ASSERT(level > 0);
- mid = path->nodes[level];
- WARN_ON(path->locks[level] != BTRFS_WRITE_LOCK &&
- path->locks[level] != BTRFS_WRITE_LOCK_BLOCKING);
- WARN_ON(btrfs_header_generation(mid) != trans->transid);
- orig_ptr = btrfs_node_blockptr(mid, orig_slot);
- if (level < BTRFS_MAX_LEVEL - 1) {
- parent = path->nodes[level + 1];
- pslot = path->slots[level + 1];
- }
- /*
- * deal with the case where there is only one pointer in the root
- * by promoting the node below to a root
- */
- if (!parent) {
- struct extent_buffer *child;
- if (btrfs_header_nritems(mid) != 1)
- return 0;
- /* promote the child to a root */
- child = btrfs_read_node_slot(mid, 0);
- if (IS_ERR(child)) {
- ret = PTR_ERR(child);
- btrfs_handle_fs_error(fs_info, ret, NULL);
- goto enospc;
- }
- btrfs_tree_lock(child);
- btrfs_set_lock_blocking_write(child);
- ret = btrfs_cow_block(trans, root, child, mid, 0, &child,
- BTRFS_NESTING_COW);
- if (ret) {
- btrfs_tree_unlock(child);
- free_extent_buffer(child);
- goto enospc;
- }
- ret = tree_mod_log_insert_root(root->node, child, 1);
- BUG_ON(ret < 0);
- rcu_assign_pointer(root->node, child);
- add_root_to_dirty_list(root);
- btrfs_tree_unlock(child);
- path->locks[level] = 0;
- path->nodes[level] = NULL;
- btrfs_clean_tree_block(mid);
- btrfs_tree_unlock(mid);
- /* once for the path */
- free_extent_buffer(mid);
- root_sub_used(root, mid->len);
- btrfs_free_tree_block(trans, root, mid, 0, 1);
- /* once for the root ptr */
- free_extent_buffer_stale(mid);
- return 0;
- }
- if (btrfs_header_nritems(mid) >
- BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 4)
- return 0;
- left = btrfs_read_node_slot(parent, pslot - 1);
- if (IS_ERR(left))
- left = NULL;
- if (left) {
- __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
- wret = btrfs_cow_block(trans, root, left,
- parent, pslot - 1, &left,
- BTRFS_NESTING_LEFT_COW);
- if (wret) {
- ret = wret;
- goto enospc;
- }
- }
- right = btrfs_read_node_slot(parent, pslot + 1);
- if (IS_ERR(right))
- right = NULL;
- if (right) {
- __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
- wret = btrfs_cow_block(trans, root, right,
- parent, pslot + 1, &right,
- BTRFS_NESTING_RIGHT_COW);
- 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) {
- btrfs_clean_tree_block(right);
- btrfs_tree_unlock(right);
- del_ptr(root, path, level + 1, pslot + 1);
- root_sub_used(root, right->len);
- btrfs_free_tree_block(trans, root, right, 0, 1);
- free_extent_buffer_stale(right);
- right = NULL;
- } else {
- struct btrfs_disk_key right_key;
- btrfs_node_key(right, &right_key, 0);
- ret = tree_mod_log_insert_key(parent, pslot + 1,
- MOD_LOG_KEY_REPLACE, GFP_NOFS);
- BUG_ON(ret < 0);
- btrfs_set_node_key(parent, &right_key, pslot + 1);
- btrfs_mark_buffer_dirty(parent);
- }
- }
- if (btrfs_header_nritems(mid) == 1) {
- /*
- * we're not allowed to leave a node with one item in the
- * tree during a delete. A deletion from lower in the tree
- * could try to delete the only pointer in this node.
- * So, pull some keys from the left.
- * There has to be a left pointer at this point because
- * otherwise we would have pulled some pointers from the
- * right
- */
- if (!left) {
- ret = -EROFS;
- btrfs_handle_fs_error(fs_info, ret, NULL);
- goto enospc;
- }
- 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) {
- btrfs_clean_tree_block(mid);
- btrfs_tree_unlock(mid);
- del_ptr(root, path, level + 1, pslot);
- root_sub_used(root, mid->len);
- btrfs_free_tree_block(trans, root, mid, 0, 1);
- free_extent_buffer_stale(mid);
- mid = NULL;
- } else {
- /* update the parent key to reflect our changes */
- struct btrfs_disk_key mid_key;
- btrfs_node_key(mid, &mid_key, 0);
- ret = tree_mod_log_insert_key(parent, pslot,
- MOD_LOG_KEY_REPLACE, GFP_NOFS);
- BUG_ON(ret < 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) {
- atomic_inc(&left->refs);
- /* left was locked after cow */
- path->nodes[level] = left;
- path->slots[level + 1] -= 1;
- path->slots[level] = orig_slot;
- if (mid) {
- btrfs_tree_unlock(mid);
- free_extent_buffer(mid);
- }
- } else {
- orig_slot -= btrfs_header_nritems(left);
- path->slots[level] = orig_slot;
- }
- }
- /* double check we haven't messed things up */
- if (orig_ptr !=
- btrfs_node_blockptr(path->nodes[level], path->slots[level]))
- BUG();
- enospc:
- if (right) {
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- }
- if (left) {
- if (path->nodes[level] != left)
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- }
- return ret;
- }
- /* Node balancing for insertion. Here we only split or push nodes around
- * when they are completely full. This is also done top down, so we
- * have to be pessimistic.
- */
- static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int level)
- {
- struct 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);
- if (IS_ERR(left))
- left = NULL;
- /* first, try to make some room in the middle buffer */
- if (left) {
- u32 left_nr;
- __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
- 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_LEFT_COW);
- 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);
- ret = tree_mod_log_insert_key(parent, pslot,
- MOD_LOG_KEY_REPLACE, GFP_NOFS);
- BUG_ON(ret < 0);
- btrfs_set_node_key(parent, &disk_key, pslot);
- btrfs_mark_buffer_dirty(parent);
- if (btrfs_header_nritems(left) > orig_slot) {
- path->nodes[level] = left;
- path->slots[level + 1] -= 1;
- path->slots[level] = orig_slot;
- btrfs_tree_unlock(mid);
- free_extent_buffer(mid);
- } else {
- orig_slot -=
- btrfs_header_nritems(left);
- path->slots[level] = orig_slot;
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- }
- return 0;
- }
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- }
- right = btrfs_read_node_slot(parent, pslot + 1);
- if (IS_ERR(right))
- right = NULL;
- /*
- * then try to empty the right most buffer into the middle
- */
- if (right) {
- u32 right_nr;
- __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
- right_nr = btrfs_header_nritems(right);
- if (right_nr >= BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 1) {
- wret = 1;
- } else {
- ret = btrfs_cow_block(trans, root, right,
- parent, pslot + 1,
- &right, BTRFS_NESTING_RIGHT_COW);
- 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);
- ret = tree_mod_log_insert_key(parent, pslot + 1,
- MOD_LOG_KEY_REPLACE, GFP_NOFS);
- BUG_ON(ret < 0);
- btrfs_set_node_key(parent, &disk_key, pslot + 1);
- btrfs_mark_buffer_dirty(parent);
- if (btrfs_header_nritems(mid) <= orig_slot) {
- path->nodes[level] = right;
- path->slots[level + 1] += 1;
- path->slots[level] = orig_slot -
- btrfs_header_nritems(mid);
- btrfs_tree_unlock(mid);
- free_extent_buffer(mid);
- } else {
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- }
- return 0;
- }
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- }
- return 1;
- }
- /*
- * readahead one full node of leaves, finding things that are close
- * to the block in 'slot', and triggering ra on them.
- */
- static void reada_for_search(struct btrfs_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 target;
- u64 nread = 0;
- struct extent_buffer *eb;
- u32 nr;
- u32 blocksize;
- u32 nscan = 0;
- if (level != 1)
- return;
- if (!path->nodes[level])
- return;
- node = path->nodes[level];
- search = btrfs_node_blockptr(node, slot);
- blocksize = fs_info->nodesize;
- eb = find_extent_buffer(fs_info, search);
- if (eb) {
- free_extent_buffer(eb);
- return;
- }
- target = search;
- nritems = btrfs_header_nritems(node);
- nr = slot;
- while (1) {
- if (path->reada == READA_BACK) {
- if (nr == 0)
- break;
- nr--;
- } else if (path->reada == READA_FORWARD) {
- nr++;
- if (nr >= nritems)
- break;
- }
- if (path->reada == READA_BACK && objectid) {
- btrfs_node_key(node, &disk_key, nr);
- if (btrfs_disk_key_objectid(&disk_key) != objectid)
- break;
- }
- search = btrfs_node_blockptr(node, nr);
- if ((search <= target && target - search <= 65536) ||
- (search > target && search - target <= 65536)) {
- readahead_tree_block(fs_info, search);
- nread += blocksize;
- }
- nscan++;
- if ((nread > 65536 || nscan > 32))
- break;
- }
- }
- static noinline void reada_for_balance(struct btrfs_fs_info *fs_info,
- struct btrfs_path *path, int level)
- {
- int slot;
- int nritems;
- struct extent_buffer *parent;
- struct extent_buffer *eb;
- u64 gen;
- u64 block1 = 0;
- u64 block2 = 0;
- parent = path->nodes[level + 1];
- if (!parent)
- return;
- nritems = btrfs_header_nritems(parent);
- slot = path->slots[level + 1];
- if (slot > 0) {
- block1 = btrfs_node_blockptr(parent, slot - 1);
- gen = btrfs_node_ptr_generation(parent, slot - 1);
- eb = find_extent_buffer(fs_info, block1);
- /*
- * if we get -eagain from btrfs_buffer_uptodate, we
- * don't want to return eagain here. That will loop
- * forever
- */
- if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
- block1 = 0;
- free_extent_buffer(eb);
- }
- if (slot + 1 < nritems) {
- block2 = btrfs_node_blockptr(parent, slot + 1);
- gen = btrfs_node_ptr_generation(parent, slot + 1);
- eb = find_extent_buffer(fs_info, block2);
- if (eb && btrfs_buffer_uptodate(eb, gen, 1) != 0)
- block2 = 0;
- free_extent_buffer(eb);
- }
- if (block1)
- readahead_tree_block(fs_info, block1);
- if (block2)
- readahead_tree_block(fs_info, block2);
- }
- /*
- * when we walk down the tree, it is usually safe to unlock the higher layers
- * in the tree. The exceptions are when our path goes through slot 0, because
- * operations on the tree might require changing key pointers higher up in the
- * tree.
- *
- * callers might also have set path->keep_locks, which tells this code to keep
- * the lock if the path points to the last slot in the block. This is part of
- * walking through the tree, and selecting the next slot in the higher block.
- *
- * lowest_unlock sets the lowest level in the tree we're allowed to unlock. so
- * if lowest_unlock is 1, level 0 won't be unlocked
- */
- static noinline void unlock_up(struct btrfs_path *path, int level,
- int lowest_unlock, int min_write_lock_level,
- int *write_lock_level)
- {
- int i;
- int skip_level = level;
- int no_skips = 0;
- struct extent_buffer *t;
- for (i = level; i < BTRFS_MAX_LEVEL; i++) {
- if (!path->nodes[i])
- break;
- if (!path->locks[i])
- break;
- if (!no_skips && path->slots[i] == 0) {
- skip_level = i + 1;
- continue;
- }
- if (!no_skips && path->keep_locks) {
- u32 nritems;
- t = path->nodes[i];
- nritems = btrfs_header_nritems(t);
- if (nritems < 1 || path->slots[i] >= nritems - 1) {
- skip_level = i + 1;
- continue;
- }
- }
- if (skip_level < i && i >= lowest_unlock)
- no_skips = 1;
- t = path->nodes[i];
- if (i >= lowest_unlock && i > skip_level) {
- btrfs_tree_unlock_rw(t, path->locks[i]);
- path->locks[i] = 0;
- if (write_lock_level &&
- i > min_write_lock_level &&
- i <= *write_lock_level) {
- *write_lock_level = i - 1;
- }
- }
- }
- }
- /*
- * helper function for btrfs_search_slot. The goal is to find a block
- * in cache without setting the path to blocking. If we find the block
- * we return zero and the path is unchanged.
- *
- * If we can't find the block, we set the path blocking and do some
- * reada. -EAGAIN is returned and the search must be repeated.
- */
- static int
- read_block_for_search(struct btrfs_root *root, struct btrfs_path *p,
- struct extent_buffer **eb_ret, int level, int slot,
- const struct btrfs_key *key)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- u64 blocknr;
- u64 gen;
- struct extent_buffer *tmp;
- struct btrfs_key first_key;
- int ret;
- int parent_level;
- blocknr = btrfs_node_blockptr(*eb_ret, slot);
- gen = btrfs_node_ptr_generation(*eb_ret, slot);
- parent_level = btrfs_header_level(*eb_ret);
- btrfs_node_key_to_cpu(*eb_ret, &first_key, slot);
- tmp = find_extent_buffer(fs_info, blocknr);
- if (tmp) {
- /* first we do an atomic uptodate check */
- if (btrfs_buffer_uptodate(tmp, gen, 1) > 0) {
- /*
- * Do extra check for first_key, eb can be stale due to
- * being cached, read from scrub, or have multiple
- * parents (shared tree blocks).
- */
- if (btrfs_verify_level_key(tmp,
- parent_level - 1, &first_key, gen)) {
- free_extent_buffer(tmp);
- return -EUCLEAN;
- }
- *eb_ret = tmp;
- return 0;
- }
- /* the pages were up to date, but we failed
- * the generation number check. Do a full
- * read for the generation number that is correct.
- * We must do this without dropping locks so
- * we can trust our generation number
- */
- btrfs_set_path_blocking(p);
- /* now we're allowed to do a blocking uptodate check */
- ret = btrfs_read_buffer(tmp, gen, parent_level - 1, &first_key);
- if (!ret) {
- *eb_ret = tmp;
- return 0;
- }
- free_extent_buffer(tmp);
- btrfs_release_path(p);
- return -EIO;
- }
- /*
- * reduce lock contention at high levels
- * of the btree by dropping locks before
- * we read. Don't release the lock on the current
- * level because we need to walk this node to figure
- * out which blocks to read.
- */
- btrfs_unlock_up_safe(p, level + 1);
- btrfs_set_path_blocking(p);
- if (p->reada != READA_NONE)
- reada_for_search(fs_info, p, level, slot, key->objectid);
- ret = -EAGAIN;
- tmp = read_tree_block(fs_info, blocknr, gen, parent_level - 1,
- &first_key);
- if (!IS_ERR(tmp)) {
- /*
- * If the read above didn't mark this buffer up to date,
- * it will never end up being up to date. Set ret to EIO now
- * and give up so that our caller doesn't loop forever
- * on our EAGAINs.
- */
- if (!extent_buffer_uptodate(tmp))
- ret = -EIO;
- free_extent_buffer(tmp);
- } else {
- ret = PTR_ERR(tmp);
- }
- btrfs_release_path(p);
- return ret;
- }
- /*
- * helper function for btrfs_search_slot. This does all of the checks
- * for node-level blocks and does any balancing required based on
- * the ins_len.
- *
- * If no extra work was required, zero is returned. If we had to
- * drop the path, -EAGAIN is returned and btrfs_search_slot must
- * start over
- */
- static int
- setup_nodes_for_search(struct btrfs_trans_handle *trans,
- struct btrfs_root *root, struct btrfs_path *p,
- struct extent_buffer *b, int level, int ins_len,
- int *write_lock_level)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- int ret;
- if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
- BTRFS_NODEPTRS_PER_BLOCK(fs_info) - 3) {
- int sret;
- if (*write_lock_level < level + 1) {
- *write_lock_level = level + 1;
- btrfs_release_path(p);
- goto again;
- }
- btrfs_set_path_blocking(p);
- reada_for_balance(fs_info, p, level);
- sret = split_node(trans, root, p, level);
- BUG_ON(sret > 0);
- if (sret) {
- ret = sret;
- goto done;
- }
- b = p->nodes[level];
- } else if (ins_len < 0 && btrfs_header_nritems(b) <
- BTRFS_NODEPTRS_PER_BLOCK(fs_info) / 2) {
- int sret;
- if (*write_lock_level < level + 1) {
- *write_lock_level = level + 1;
- btrfs_release_path(p);
- goto again;
- }
- btrfs_set_path_blocking(p);
- reada_for_balance(fs_info, p, level);
- sret = balance_level(trans, root, p, level);
- if (sret) {
- ret = sret;
- goto done;
- }
- b = p->nodes[level];
- if (!b) {
- btrfs_release_path(p);
- goto again;
- }
- BUG_ON(btrfs_header_nritems(b) == 1);
- }
- return 0;
- again:
- ret = -EAGAIN;
- done:
- return ret;
- }
- int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
- u64 iobjectid, u64 ioff, u8 key_type,
- struct btrfs_key *found_key)
- {
- int ret;
- struct btrfs_key key;
- struct extent_buffer *eb;
- ASSERT(path);
- ASSERT(found_key);
- key.type = key_type;
- key.objectid = iobjectid;
- key.offset = ioff;
- ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
- if (ret < 0)
- return ret;
- eb = path->nodes[0];
- if (ret && path->slots[0] >= btrfs_header_nritems(eb)) {
- ret = btrfs_next_leaf(fs_root, path);
- if (ret)
- return ret;
- 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)
- return 1;
- return 0;
- }
- static struct extent_buffer *btrfs_search_slot_get_root(struct btrfs_root *root,
- struct btrfs_path *p,
- int write_lock_level)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *b;
- int root_lock = 0;
- int level = 0;
- if (p->search_commit_root) {
- /*
- * The commit roots are read only so we always do read locks,
- * and we always must hold the commit_root_sem when doing
- * searches on them, the only exception is send where we don't
- * want to block transaction commits for a long time, so
- * we need to clone the commit root in order to avoid races
- * with transaction commits that create a snapshot of one of
- * the roots used by a send operation.
- */
- if (p->need_commit_sem) {
- down_read(&fs_info->commit_root_sem);
- b = btrfs_clone_extent_buffer(root->commit_root);
- up_read(&fs_info->commit_root_sem);
- if (!b)
- return ERR_PTR(-ENOMEM);
- } else {
- b = root->commit_root;
- atomic_inc(&b->refs);
- }
- level = btrfs_header_level(b);
- /*
- * Ensure that all callers have set skip_locking when
- * p->search_commit_root = 1.
- */
- ASSERT(p->skip_locking == 1);
- goto out;
- }
- if (p->skip_locking) {
- b = btrfs_root_node(root);
- level = btrfs_header_level(b);
- goto out;
- }
- /* We try very hard to do read locks on the root */
- root_lock = BTRFS_READ_LOCK;
- /*
- * If the level is set to maximum, we can skip trying to get the read
- * lock.
- */
- if (write_lock_level < BTRFS_MAX_LEVEL) {
- /*
- * We don't know the level of the root node until we actually
- * have it read locked
- */
- b = __btrfs_read_lock_root_node(root, p->recurse);
- level = btrfs_header_level(b);
- if (level > write_lock_level)
- goto out;
- /* Whoops, must trade for write lock */
- btrfs_tree_read_unlock(b);
- free_extent_buffer(b);
- }
- b = btrfs_lock_root_node(root);
- root_lock = BTRFS_WRITE_LOCK;
- /* The level might have changed, check again */
- level = btrfs_header_level(b);
- out:
- /*
- * The root may have failed to write out at some point, and thus is no
- * longer valid, return an error in this case.
- */
- if (!extent_buffer_uptodate(b)) {
- if (root_lock)
- btrfs_tree_unlock_rw(b, root_lock);
- free_extent_buffer(b);
- return ERR_PTR(-EIO);
- }
- p->nodes[level] = b;
- if (!p->skip_locking)
- p->locks[level] = root_lock;
- /*
- * Callers are responsible for dropping b's references.
- */
- return b;
- }
- /*
- * btrfs_search_slot - look for a key in a tree and perform necessary
- * modifications to preserve tree invariants.
- *
- * @trans: Handle of transaction, used when modifying the tree
- * @p: Holds all btree nodes along the search path
- * @root: The root node of the tree
- * @key: The key we are looking for
- * @ins_len: Indicates purpose of search, for inserts it is 1, for
- * deletions it's -1. 0 for plain searches
- * @cow: boolean should CoW operations be performed. Must always be 1
- * when modifying the tree.
- *
- * 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)
- *
- * If @key is found, 0 is returned and you can find the item in the leaf level
- * of the path (level 0)
- *
- * If @key isn't found, 1 is returned and the leaf level of the path (level 0)
- * points to the slot where it should be inserted
- *
- * If an error is encountered while searching the tree a negative error number
- * is returned
- */
- 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 err;
- int level;
- int lowest_unlock = 1;
- /* everything at write_lock_level or lower must be write locked */
- int write_lock_level = 0;
- u8 lowest_level = 0;
- int min_write_lock_level;
- int prev_cmp;
- lowest_level = p->lowest_level;
- WARN_ON(lowest_level && ins_len > 0);
- WARN_ON(p->nodes[0] != NULL);
- BUG_ON(!cow && ins_len);
- if (ins_len < 0) {
- lowest_unlock = 2;
- /* when we are removing items, we might have to go up to level
- * two as we update tree pointers Make sure we keep write
- * for those levels as well
- */
- write_lock_level = 2;
- } else if (ins_len > 0) {
- /*
- * for inserting items, make sure we have a write lock on
- * level 1 so we can update keys
- */
- write_lock_level = 1;
- }
- if (!cow)
- write_lock_level = -1;
- if (cow && (p->keep_locks || p->lowest_level))
- write_lock_level = BTRFS_MAX_LEVEL;
- min_write_lock_level = write_lock_level;
- again:
- prev_cmp = -1;
- b = btrfs_search_slot_get_root(root, p, write_lock_level);
- if (IS_ERR(b)) {
- ret = PTR_ERR(b);
- goto done;
- }
- while (b) {
- int dec = 0;
- level = btrfs_header_level(b);
- if (cow) {
- bool last_level = (level == (BTRFS_MAX_LEVEL - 1));
- /*
- * if we don't really need to cow this block
- * then we don't want to set the path blocking,
- * so we test it here
- */
- if (!should_cow_block(trans, root, b)) {
- trans->dirty = true;
- goto cow_done;
- }
- /*
- * must have write locks on this node and the
- * parent
- */
- if (level > write_lock_level ||
- (level + 1 > write_lock_level &&
- level + 1 < BTRFS_MAX_LEVEL &&
- p->nodes[level + 1])) {
- write_lock_level = level + 1;
- btrfs_release_path(p);
- goto again;
- }
- btrfs_set_path_blocking(p);
- if (last_level)
- err = btrfs_cow_block(trans, root, b, NULL, 0,
- &b,
- BTRFS_NESTING_COW);
- else
- err = btrfs_cow_block(trans, root, b,
- p->nodes[level + 1],
- p->slots[level + 1], &b,
- BTRFS_NESTING_COW);
- if (err) {
- ret = err;
- goto done;
- }
- }
- cow_done:
- p->nodes[level] = b;
- /*
- * Leave path with blocking locks to avoid massive
- * lock context switch, this is made on purpose.
- */
- /*
- * we have a lock on b and as long as we aren't changing
- * the tree, there is no way to for the items in b to change.
- * It is safe to drop the lock on our parent before we
- * go through the expensive btree search on b.
- *
- * If we're inserting or deleting (ins_len != 0), then we might
- * be changing slot zero, which may require changing the parent.
- * So, we can't drop the lock until after we know which slot
- * we're operating on.
- */
- if (!ins_len && !p->keep_locks) {
- int u = level + 1;
- if (u < BTRFS_MAX_LEVEL && p->locks[u]) {
- btrfs_tree_unlock_rw(p->nodes[u], p->locks[u]);
- p->locks[u] = 0;
- }
- }
- /*
- * If btrfs_bin_search returns an exact match (prev_cmp == 0)
- * we can safely assume the target key will always be in slot 0
- * on lower levels due to the invariants BTRFS' btree provides,
- * namely that a btrfs_key_ptr entry always points to the
- * lowest key in the child node, thus we can skip searching
- * lower levels
- */
- if (prev_cmp == 0) {
- slot = 0;
- ret = 0;
- } else {
- ret = btrfs_bin_search(b, key, &slot);
- prev_cmp = ret;
- if (ret < 0)
- goto done;
- }
- if (level == 0) {
- p->slots[level] = slot;
- if (ins_len > 0 &&
- btrfs_leaf_free_space(b) < ins_len) {
- if (write_lock_level < 1) {
- write_lock_level = 1;
- btrfs_release_path(p);
- goto again;
- }
- btrfs_set_path_blocking(p);
- err = split_leaf(trans, root, key,
- p, ins_len, ret == 0);
- BUG_ON(err > 0);
- if (err) {
- ret = err;
- goto done;
- }
- }
- if (!p->search_for_split)
- unlock_up(p, level, lowest_unlock,
- min_write_lock_level, NULL);
- goto done;
- }
- if (ret && slot > 0) {
- dec = 1;
- slot--;
- }
- p->slots[level] = slot;
- err = setup_nodes_for_search(trans, root, p, b, level, ins_len,
- &write_lock_level);
- if (err == -EAGAIN)
- goto again;
- if (err) {
- ret = err;
- goto done;
- }
- b = p->nodes[level];
- slot = p->slots[level];
- /*
- * Slot 0 is special, if we change the key we have to update
- * the parent pointer which means we must have a write lock on
- * the parent
- */
- if (slot == 0 && ins_len && write_lock_level < level + 1) {
- write_lock_level = level + 1;
- btrfs_release_path(p);
- goto again;
- }
- unlock_up(p, level, lowest_unlock, min_write_lock_level,
- &write_lock_level);
- if (level == lowest_level) {
- if (dec)
- p->slots[level]++;
- goto done;
- }
- err = read_block_for_search(root, p, &b, level, slot, key);
- if (err == -EAGAIN)
- goto again;
- if (err) {
- ret = err;
- goto done;
- }
- if (!p->skip_locking) {
- level = btrfs_header_level(b);
- if (level <= write_lock_level) {
- if (!btrfs_try_tree_write_lock(b)) {
- btrfs_set_path_blocking(p);
- btrfs_tree_lock(b);
- }
- p->locks[level] = BTRFS_WRITE_LOCK;
- } else {
- if (!btrfs_tree_read_lock_atomic(b)) {
- btrfs_set_path_blocking(p);
- __btrfs_tree_read_lock(b, BTRFS_NESTING_NORMAL,
- p->recurse);
- }
- p->locks[level] = BTRFS_READ_LOCK;
- }
- p->nodes[level] = b;
- }
- }
- ret = 1;
- done:
- /*
- * we don't really know what they plan on doing with the path
- * from here on, so for now just mark it as blocking
- */
- if (!p->leave_spinning)
- btrfs_set_path_blocking(p);
- if (ret < 0 && !p->skip_release_on_error)
- btrfs_release_path(p);
- return ret;
- }
- /*
- * Like btrfs_search_slot, this looks for a key in the given tree. It uses the
- * current state of the tree together with the operations recorded in the tree
- * modification log to search for the key in a previous version of this tree, as
- * denoted by the time_seq parameter.
- *
- * Naturally, there is no support for insert, delete or cow operations.
- *
- * The resulting path and return value will be set up as if we called
- * btrfs_search_slot at that point in time with ins_len and cow both set to 0.
- */
- int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
- struct btrfs_path *p, u64 time_seq)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *b;
- int slot;
- int ret;
- int err;
- int level;
- int lowest_unlock = 1;
- u8 lowest_level = 0;
- lowest_level = p->lowest_level;
- WARN_ON(p->nodes[0] != NULL);
- if (p->search_commit_root) {
- BUG_ON(time_seq);
- return btrfs_search_slot(NULL, root, key, p, 0, 0);
- }
- again:
- b = get_old_root(root, time_seq);
- if (!b) {
- ret = -EIO;
- goto done;
- }
- level = btrfs_header_level(b);
- p->locks[level] = BTRFS_READ_LOCK;
- while (b) {
- int dec = 0;
- level = btrfs_header_level(b);
- p->nodes[level] = b;
- /*
- * we have a lock on b and as long as we aren't changing
- * the tree, there is no way to for the items in b to change.
- * It is safe to drop the lock on our parent before we
- * go through the expensive btree search on b.
- */
- btrfs_unlock_up_safe(p, level + 1);
- ret = btrfs_bin_search(b, key, &slot);
- if (ret < 0)
- goto done;
- if (level == 0) {
- p->slots[level] = slot;
- unlock_up(p, level, lowest_unlock, 0, NULL);
- goto done;
- }
- if (ret && slot > 0) {
- dec = 1;
- slot--;
- }
- p->slots[level] = slot;
- unlock_up(p, level, lowest_unlock, 0, NULL);
- if (level == lowest_level) {
- if (dec)
- p->slots[level]++;
- goto done;
- }
- err = read_block_for_search(root, p, &b, level, slot, key);
- if (err == -EAGAIN)
- goto again;
- if (err) {
- ret = err;
- goto done;
- }
- level = btrfs_header_level(b);
- if (!btrfs_tree_read_lock_atomic(b)) {
- btrfs_set_path_blocking(p);
- btrfs_tree_read_lock(b);
- }
- b = tree_mod_log_rewind(fs_info, p, b, time_seq);
- if (!b) {
- ret = -ENOMEM;
- goto done;
- }
- p->locks[level] = BTRFS_READ_LOCK;
- p->nodes[level] = b;
- }
- ret = 1;
- done:
- if (!p->leave_spinning)
- btrfs_set_path_blocking(p);
- if (ret < 0)
- btrfs_release_path(p);
- return ret;
- }
- /*
- * 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;
- int ret;
- for (i = level; i < BTRFS_MAX_LEVEL; i++) {
- int tslot = path->slots[i];
- if (!path->nodes[i])
- break;
- t = path->nodes[i];
- ret = tree_mod_log_insert_key(t, tslot, MOD_LOG_KEY_REPLACE,
- GFP_ATOMIC);
- BUG_ON(ret < 0);
- 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);
- if (unlikely(comp_keys(&disk_key, new_key) >= 0)) {
- btrfs_crit(fs_info,
- "slot %u key (%llu %u %llu) new key (%llu %u %llu)",
- slot, btrfs_disk_key_objectid(&disk_key),
- btrfs_disk_key_type(&disk_key),
- btrfs_disk_key_offset(&disk_key),
- new_key->objectid, new_key->type,
- new_key->offset);
- btrfs_print_leaf(eb);
- BUG();
- }
- }
- if (slot < btrfs_header_nritems(eb) - 1) {
- btrfs_item_key(eb, &disk_key, slot + 1);
- if (unlikely(comp_keys(&disk_key, new_key) <= 0)) {
- btrfs_crit(fs_info,
- "slot %u key (%llu %u %llu) new key (%llu %u %llu)",
- slot, btrfs_disk_key_objectid(&disk_key),
- btrfs_disk_key_type(&disk_key),
- btrfs_disk_key_offset(&disk_key),
- new_key->objectid, new_key->type,
- new_key->offset);
- btrfs_print_leaf(eb);
- BUG();
- }
- }
- 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);
- }
- /*
- * Check key order of two sibling extent buffers.
- *
- * Return true if something is wrong.
- * Return false if everything is fine.
- *
- * Tree-checker only works inside one tree block, thus the following
- * corruption can not be detected by tree-checker:
- *
- * Leaf @left | Leaf @right
- * --------------------------------------------------------------
- * | 1 | 2 | 3 | 4 | 5 | f6 | | 7 | 8 |
- *
- * Key f6 in leaf @left itself is valid, but not valid when the next
- * key in leaf @right is 7.
- * This can only be checked at tree block merge time.
- * And since tree checker has ensured all key order in each tree block
- * is correct, we only need to bother the last key of @left and the first
- * key of @right.
- */
- static bool check_sibling_keys(struct extent_buffer *left,
- struct extent_buffer *right)
- {
- struct btrfs_key left_last;
- struct btrfs_key right_first;
- int level = btrfs_header_level(left);
- int nr_left = btrfs_header_nritems(left);
- int nr_right = btrfs_header_nritems(right);
- /* No key to check in one of the tree blocks */
- if (!nr_left || !nr_right)
- return false;
- if (level) {
- btrfs_node_key_to_cpu(left, &left_last, nr_left - 1);
- btrfs_node_key_to_cpu(right, &right_first, 0);
- } else {
- btrfs_item_key_to_cpu(left, &left_last, nr_left - 1);
- btrfs_item_key_to_cpu(right, &right_first, 0);
- }
- if (btrfs_comp_cpu_keys(&left_last, &right_first) >= 0) {
- btrfs_crit(left->fs_info,
- "bad key order, sibling blocks, left last (%llu %u %llu) right first (%llu %u %llu)",
- left_last.objectid, left_last.type,
- left_last.offset, right_first.objectid,
- right_first.type, right_first.offset);
- return true;
- }
- return false;
- }
- /*
- * 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);
- /* dst is the left eb, src is the middle eb */
- if (check_sibling_keys(dst, src)) {
- ret = -EUCLEAN;
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- ret = tree_mod_log_eb_copy(dst, src, dst_nritems, 0, push_items);
- if (ret) {
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- copy_extent_buffer(dst, src,
- btrfs_node_key_ptr_offset(dst_nritems),
- btrfs_node_key_ptr_offset(0),
- push_items * sizeof(struct btrfs_key_ptr));
- if (push_items < src_nritems) {
- /*
- * Don't call tree_mod_log_insert_move here, key removal was
- * already fully logged by tree_mod_log_eb_copy above.
- */
- memmove_extent_buffer(src, btrfs_node_key_ptr_offset(0),
- btrfs_node_key_ptr_offset(push_items),
- (src_nritems - push_items) *
- sizeof(struct btrfs_key_ptr));
- }
- btrfs_set_header_nritems(src, src_nritems - push_items);
- btrfs_set_header_nritems(dst, dst_nritems + push_items);
- btrfs_mark_buffer_dirty(src);
- btrfs_mark_buffer_dirty(dst);
- return ret;
- }
- /*
- * try to push data from one node into the next node right in the
- * tree.
- *
- * returns 0 if some ptrs were pushed, < 0 if there was some horrible
- * error, and > 0 if there was no room in the right hand block.
- *
- * this will only push up to 1/2 the contents of the left node over
- */
- static int balance_node_right(struct btrfs_trans_handle *trans,
- struct 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;
- /* dst is the right eb, src is the middle eb */
- if (check_sibling_keys(src, dst)) {
- ret = -EUCLEAN;
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- ret = tree_mod_log_insert_move(dst, push_items, 0, dst_nritems);
- BUG_ON(ret < 0);
- memmove_extent_buffer(dst, btrfs_node_key_ptr_offset(push_items),
- btrfs_node_key_ptr_offset(0),
- (dst_nritems) *
- sizeof(struct btrfs_key_ptr));
- ret = tree_mod_log_eb_copy(dst, src, 0, src_nritems - push_items,
- push_items);
- if (ret) {
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- copy_extent_buffer(dst, src,
- btrfs_node_key_ptr_offset(0),
- btrfs_node_key_ptr_offset(src_nritems - push_items),
- push_items * sizeof(struct btrfs_key_ptr));
- btrfs_set_header_nritems(src, src_nritems - push_items);
- btrfs_set_header_nritems(dst, dst_nritems + push_items);
- btrfs_mark_buffer_dirty(src);
- btrfs_mark_buffer_dirty(dst);
- return ret;
- }
- /*
- * helper function to insert a new root level in the tree.
- * A new node is allocated, and a single item is inserted to
- * point to the existing root
- *
- * returns zero on success or < 0 on failure.
- */
- static noinline int insert_new_root(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int level)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- u64 lower_gen;
- struct extent_buffer *lower;
- struct extent_buffer *c;
- struct extent_buffer *old;
- struct btrfs_disk_key lower_key;
- int ret;
- 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 = alloc_tree_block_no_bg_flush(trans, root, 0, &lower_key, level,
- root->node->start, 0,
- BTRFS_NESTING_NEW_ROOT);
- if (IS_ERR(c))
- return PTR_ERR(c);
- root_add_used(root, fs_info->nodesize);
- btrfs_set_header_nritems(c, 1);
- 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;
- ret = tree_mod_log_insert_root(root->node, c, 0);
- BUG_ON(ret < 0);
- rcu_assign_pointer(root->node, c);
- /* the super has an extra ref to root->node */
- free_extent_buffer(old);
- add_root_to_dirty_list(root);
- atomic_inc(&c->refs);
- path->nodes[level] = c;
- path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
- path->slots[level] = 0;
- return 0;
- }
- /*
- * worker function to insert a single pointer in a node.
- * the node should have enough room for the pointer already
- *
- * slot and level indicate where you want the key to go, and
- * blocknr is the block the key points to.
- */
- static void insert_ptr(struct btrfs_trans_handle *trans,
- struct btrfs_path *path,
- struct btrfs_disk_key *key, u64 bytenr,
- int slot, int level)
- {
- struct extent_buffer *lower;
- int nritems;
- int ret;
- BUG_ON(!path->nodes[level]);
- btrfs_assert_tree_locked(path->nodes[level]);
- lower = path->nodes[level];
- nritems = btrfs_header_nritems(lower);
- BUG_ON(slot > nritems);
- BUG_ON(nritems == BTRFS_NODEPTRS_PER_BLOCK(trans->fs_info));
- if (slot != nritems) {
- if (level) {
- ret = tree_mod_log_insert_move(lower, slot + 1, slot,
- nritems - slot);
- BUG_ON(ret < 0);
- }
- memmove_extent_buffer(lower,
- btrfs_node_key_ptr_offset(slot + 1),
- btrfs_node_key_ptr_offset(slot),
- (nritems - slot) * sizeof(struct btrfs_key_ptr));
- }
- if (level) {
- ret = tree_mod_log_insert_key(lower, slot, MOD_LOG_KEY_ADD,
- GFP_NOFS);
- BUG_ON(ret < 0);
- }
- btrfs_set_node_key(lower, key, slot);
- btrfs_set_node_blockptr(lower, slot, bytenr);
- WARN_ON(trans->transid == 0);
- btrfs_set_node_ptr_generation(lower, slot, trans->transid);
- btrfs_set_header_nritems(lower, nritems + 1);
- btrfs_mark_buffer_dirty(lower);
- }
- /*
- * split the node at the specified level in path in two.
- * The path is corrected to point to the appropriate node after the split
- *
- * Before splitting this tries to make some room in the node by pushing
- * left and right, if either one works, it returns right away.
- *
- * returns 0 on success and < 0 on failure
- */
- static noinline int split_node(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int level)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *c;
- struct extent_buffer *split;
- struct btrfs_disk_key disk_key;
- int mid;
- int ret;
- u32 c_nritems;
- c = path->nodes[level];
- WARN_ON(btrfs_header_generation(c) != trans->transid);
- if (c == root->node) {
- /*
- * trying to split the root, lets make a new one
- *
- * tree mod log: We don't log_removal old root in
- * insert_new_root, because that root buffer will be kept as a
- * normal node. We are going to log removal of half of the
- * elements below with tree_mod_log_eb_copy. We're holding a
- * tree lock on the buffer, which is why we cannot race with
- * other tree_mod_log users.
- */
- 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(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 = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, level,
- c->start, 0, BTRFS_NESTING_SPLIT);
- if (IS_ERR(split))
- return PTR_ERR(split);
- root_add_used(root, fs_info->nodesize);
- ASSERT(btrfs_header_level(c) == level);
- ret = tree_mod_log_eb_copy(split, c, 0, mid, c_nritems - mid);
- if (ret) {
- btrfs_abort_transaction(trans, ret);
- return ret;
- }
- copy_extent_buffer(split, c,
- btrfs_node_key_ptr_offset(0),
- btrfs_node_key_ptr_offset(mid),
- (c_nritems - mid) * sizeof(struct btrfs_key_ptr));
- btrfs_set_header_nritems(split, c_nritems - mid);
- btrfs_set_header_nritems(c, mid);
- ret = 0;
- btrfs_mark_buffer_dirty(c);
- btrfs_mark_buffer_dirty(split);
- insert_ptr(trans, path, &disk_key, split->start,
- path->slots[level + 1] + 1, level + 1);
- if (path->slots[level] >= mid) {
- path->slots[level] -= mid;
- btrfs_tree_unlock(c);
- free_extent_buffer(c);
- path->nodes[level] = split;
- path->slots[level + 1] += 1;
- } else {
- btrfs_tree_unlock(split);
- free_extent_buffer(split);
- }
- return ret;
- }
- /*
- * how many bytes are required to store the items in a leaf. start
- * and nr indicate which items in the leaf to check. This totals up the
- * space used both by the item structs and the item data
- */
- static int leaf_space_used(struct extent_buffer *l, int start, int nr)
- {
- struct btrfs_item *start_item;
- struct btrfs_item *end_item;
- int data_len;
- int nritems = btrfs_header_nritems(l);
- int end = min(nritems, start + nr) - 1;
- if (!nr)
- return 0;
- start_item = btrfs_item_nr(start);
- end_item = btrfs_item_nr(end);
- data_len = btrfs_item_offset(l, start_item) +
- btrfs_item_size(l, start_item);
- data_len = data_len - btrfs_item_offset(l, end_item);
- data_len += sizeof(struct btrfs_item) * nr;
- WARN_ON(data_len < 0);
- return data_len;
- }
- /*
- * The space between the end of the leaf items and
- * the start of the leaf data. IOW, how much room
- * the leaf has left for both items and data
- */
- noinline int btrfs_leaf_free_space(struct extent_buffer *leaf)
- {
- struct btrfs_fs_info *fs_info = leaf->fs_info;
- int nritems = btrfs_header_nritems(leaf);
- int ret;
- ret = BTRFS_LEAF_DATA_SIZE(fs_info) - leaf_space_used(leaf, 0, nritems);
- if (ret < 0) {
- btrfs_crit(fs_info,
- "leaf free space ret %d, leaf data size %lu, used %d nritems %d",
- ret,
- (unsigned long) BTRFS_LEAF_DATA_SIZE(fs_info),
- leaf_space_used(leaf, 0, nritems), nritems);
- }
- return ret;
- }
- /*
- * min slot controls the lowest index we're willing to push to the
- * right. We'll push up to and including min_slot, but no lower
- */
- static noinline int __push_leaf_right(struct btrfs_path *path,
- int data_size, int empty,
- struct extent_buffer *right,
- int free_space, u32 left_nritems,
- u32 min_slot)
- {
- struct btrfs_fs_info *fs_info = right->fs_info;
- struct extent_buffer *left = path->nodes[0];
- struct extent_buffer *upper = path->nodes[1];
- struct btrfs_map_token token;
- struct btrfs_disk_key disk_key;
- int slot;
- u32 i;
- int push_space = 0;
- int push_items = 0;
- struct btrfs_item *item;
- u32 nr;
- u32 right_nritems;
- u32 data_end;
- u32 this_item_size;
- if (empty)
- nr = 0;
- else
- nr = max_t(u32, 1, min_slot);
- if (path->slots[0] >= left_nritems)
- push_space += data_size;
- slot = path->slots[1];
- i = left_nritems - 1;
- while (i >= nr) {
- item = btrfs_item_nr(i);
- if (!empty && push_items > 0) {
- if (path->slots[0] > i)
- break;
- if (path->slots[0] == i) {
- int space = btrfs_leaf_free_space(left);
- if (space + push_space * 2 > free_space)
- break;
- }
- }
- if (path->slots[0] == i)
- push_space += data_size;
- this_item_size = btrfs_item_size(left, item);
- if (this_item_size + sizeof(*item) + push_space > free_space)
- break;
- push_items++;
- push_space += this_item_size + sizeof(*item);
- if (i == 0)
- break;
- i--;
- }
- if (push_items == 0)
- goto out_unlock;
- WARN_ON(!empty && push_items == left_nritems);
- /* push left to right */
- right_nritems = btrfs_header_nritems(right);
- push_space = btrfs_item_end_nr(left, left_nritems - push_items);
- push_space -= leaf_data_end(left);
- /* make room in the right data area */
- data_end = leaf_data_end(right);
- memmove_extent_buffer(right,
- BTRFS_LEAF_DATA_OFFSET + data_end - push_space,
- BTRFS_LEAF_DATA_OFFSET + data_end,
- BTRFS_LEAF_DATA_SIZE(fs_info) - data_end);
- /* copy from the left data area */
- copy_extent_buffer(right, left, BTRFS_LEAF_DATA_OFFSET +
- BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
- BTRFS_LEAF_DATA_OFFSET + leaf_data_end(left),
- push_space);
- memmove_extent_buffer(right, btrfs_item_nr_offset(push_items),
- btrfs_item_nr_offset(0),
- right_nritems * sizeof(struct btrfs_item));
- /* copy the items from left to right */
- copy_extent_buffer(right, left, btrfs_item_nr_offset(0),
- btrfs_item_nr_offset(left_nritems - push_items),
- push_items * sizeof(struct btrfs_item));
- /* update the item pointers */
- btrfs_init_map_token(&token, right);
- right_nritems += push_items;
- btrfs_set_header_nritems(right, right_nritems);
- push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
- for (i = 0; i < right_nritems; i++) {
- item = btrfs_item_nr(i);
- push_space -= btrfs_token_item_size(&token, item);
- btrfs_set_token_item_offset(&token, item, push_space);
- }
- left_nritems -= push_items;
- btrfs_set_header_nritems(left, left_nritems);
- if (left_nritems)
- btrfs_mark_buffer_dirty(left);
- else
- btrfs_clean_tree_block(left);
- btrfs_mark_buffer_dirty(right);
- btrfs_item_key(right, &disk_key, 0);
- btrfs_set_node_key(upper, &disk_key, slot + 1);
- btrfs_mark_buffer_dirty(upper);
- /* then fixup the leaf pointer in the path */
- if (path->slots[0] >= left_nritems) {
- path->slots[0] -= left_nritems;
- if (btrfs_header_nritems(path->nodes[0]) == 0)
- btrfs_clean_tree_block(path->nodes[0]);
- btrfs_tree_unlock(path->nodes[0]);
- free_extent_buffer(path->nodes[0]);
- path->nodes[0] = right;
- path->slots[1] += 1;
- } else {
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- }
- return 0;
- out_unlock:
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- return 1;
- }
- /*
- * push some data in the path leaf to the right, trying to free up at
- * least data_size bytes. returns zero if the push worked, nonzero otherwise
- *
- * returns 1 if the push failed because the other node didn't have enough
- * room, 0 if everything worked out and < 0 if there were major errors.
- *
- * this will push starting from min_slot to the end of the leaf. It won't
- * push any slot lower than min_slot
- */
- static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, struct btrfs_path *path,
- int min_data_size, int data_size,
- int empty, u32 min_slot)
- {
- struct extent_buffer *left = path->nodes[0];
- struct extent_buffer *right;
- struct extent_buffer *upper;
- int slot;
- int free_space;
- u32 left_nritems;
- int ret;
- if (!path->nodes[1])
- return 1;
- slot = path->slots[1];
- upper = path->nodes[1];
- if (slot >= btrfs_header_nritems(upper) - 1)
- return 1;
- btrfs_assert_tree_locked(path->nodes[1]);
- right = btrfs_read_node_slot(upper, slot + 1);
- /*
- * slot + 1 is not valid or we fail to read the right node,
- * no big deal, just return.
- */
- if (IS_ERR(right))
- return 1;
- __btrfs_tree_lock(right, BTRFS_NESTING_RIGHT);
- btrfs_set_lock_blocking_write(right);
- free_space = btrfs_leaf_free_space(right);
- if (free_space < data_size)
- goto out_unlock;
- /* cow and double check */
- ret = btrfs_cow_block(trans, root, right, upper,
- slot + 1, &right, BTRFS_NESTING_RIGHT_COW);
- if (ret)
- goto out_unlock;
- free_space = btrfs_leaf_free_space(right);
- if (free_space < data_size)
- goto out_unlock;
- left_nritems = btrfs_header_nritems(left);
- if (left_nritems == 0)
- goto out_unlock;
- if (check_sibling_keys(left, right)) {
- ret = -EUCLEAN;
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- return ret;
- }
- if (path->slots[0] == left_nritems && !empty) {
- /* Key greater than all keys in the leaf, right neighbor has
- * enough room for it and we're not emptying our leaf to delete
- * it, therefore use right neighbor to insert the new item and
- * no need to touch/dirty our left leaf. */
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- path->nodes[0] = right;
- path->slots[0] = 0;
- path->slots[1]++;
- return 0;
- }
- return __push_leaf_right(path, min_data_size, empty,
- right, free_space, left_nritems, min_slot);
- out_unlock:
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- return 1;
- }
- /*
- * push some data in the path leaf to the left, trying to free up at
- * least data_size bytes. returns zero if the push worked, nonzero otherwise
- *
- * max_slot can put a limit on how far into the leaf we'll push items. The
- * item at 'max_slot' won't be touched. Use (u32)-1 to make us do all the
- * items
- */
- static noinline int __push_leaf_left(struct btrfs_path *path, int data_size,
- int empty, struct extent_buffer *left,
- int free_space, u32 right_nritems,
- u32 max_slot)
- {
- struct btrfs_fs_info *fs_info = left->fs_info;
- struct btrfs_disk_key disk_key;
- struct extent_buffer *right = path->nodes[0];
- int i;
- int push_space = 0;
- int push_items = 0;
- struct btrfs_item *item;
- u32 old_left_nritems;
- u32 nr;
- int ret = 0;
- u32 this_item_size;
- u32 old_left_item_size;
- struct btrfs_map_token token;
- if (empty)
- nr = min(right_nritems, max_slot);
- else
- nr = min(right_nritems - 1, max_slot);
- for (i = 0; i < nr; i++) {
- item = btrfs_item_nr(i);
- if (!empty && push_items > 0) {
- if (path->slots[0] < i)
- break;
- if (path->slots[0] == i) {
- int space = btrfs_leaf_free_space(right);
- if (space + push_space * 2 > free_space)
- break;
- }
- }
- if (path->slots[0] == i)
- push_space += data_size;
- this_item_size = btrfs_item_size(right, item);
- if (this_item_size + sizeof(*item) + push_space > free_space)
- break;
- push_items++;
- push_space += this_item_size + sizeof(*item);
- }
- if (push_items == 0) {
- ret = 1;
- goto out;
- }
- WARN_ON(!empty && push_items == btrfs_header_nritems(right));
- /* push data from right to left */
- copy_extent_buffer(left, right,
- btrfs_item_nr_offset(btrfs_header_nritems(left)),
- btrfs_item_nr_offset(0),
- push_items * sizeof(struct btrfs_item));
- push_space = BTRFS_LEAF_DATA_SIZE(fs_info) -
- btrfs_item_offset_nr(right, push_items - 1);
- copy_extent_buffer(left, right, BTRFS_LEAF_DATA_OFFSET +
- leaf_data_end(left) - push_space,
- BTRFS_LEAF_DATA_OFFSET +
- btrfs_item_offset_nr(right, push_items - 1),
- push_space);
- old_left_nritems = btrfs_header_nritems(left);
- BUG_ON(old_left_nritems <= 0);
- btrfs_init_map_token(&token, left);
- old_left_item_size = btrfs_item_offset_nr(left, old_left_nritems - 1);
- for (i = old_left_nritems; i < old_left_nritems + push_items; i++) {
- u32 ioff;
- item = btrfs_item_nr(i);
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item,
- ioff - (BTRFS_LEAF_DATA_SIZE(fs_info) - old_left_item_size));
- }
- btrfs_set_header_nritems(left, old_left_nritems + push_items);
- /* fixup right node */
- if (push_items > right_nritems)
- WARN(1, KERN_CRIT "push items %d nr %u\n", push_items,
- right_nritems);
- if (push_items < right_nritems) {
- push_space = btrfs_item_offset_nr(right, push_items - 1) -
- leaf_data_end(right);
- memmove_extent_buffer(right, BTRFS_LEAF_DATA_OFFSET +
- BTRFS_LEAF_DATA_SIZE(fs_info) - push_space,
- BTRFS_LEAF_DATA_OFFSET +
- leaf_data_end(right), push_space);
- memmove_extent_buffer(right, btrfs_item_nr_offset(0),
- btrfs_item_nr_offset(push_items),
- (btrfs_header_nritems(right) - push_items) *
- sizeof(struct btrfs_item));
- }
- btrfs_init_map_token(&token, right);
- right_nritems -= push_items;
- btrfs_set_header_nritems(right, right_nritems);
- push_space = BTRFS_LEAF_DATA_SIZE(fs_info);
- for (i = 0; i < right_nritems; i++) {
- item = btrfs_item_nr(i);
- push_space = push_space - btrfs_token_item_size(&token, item);
- btrfs_set_token_item_offset(&token, item, push_space);
- }
- btrfs_mark_buffer_dirty(left);
- if (right_nritems)
- btrfs_mark_buffer_dirty(right);
- else
- btrfs_clean_tree_block(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;
- btrfs_tree_unlock(path->nodes[0]);
- free_extent_buffer(path->nodes[0]);
- path->nodes[0] = left;
- path->slots[1] -= 1;
- } else {
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- path->slots[0] -= push_items;
- }
- BUG_ON(path->slots[0] < 0);
- return ret;
- out:
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- return ret;
- }
- /*
- * push some data in the path leaf to the left, trying to free up at
- * least data_size bytes. returns zero if the push worked, nonzero otherwise
- *
- * max_slot can put a limit on how far into the leaf we'll push items. The
- * item at 'max_slot' won't be touched. Use (u32)-1 to make us push all the
- * items
- */
- static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
- *root, struct btrfs_path *path, int min_data_size,
- int data_size, int empty, u32 max_slot)
- {
- struct extent_buffer *right = path->nodes[0];
- struct extent_buffer *left;
- int slot;
- int free_space;
- u32 right_nritems;
- int ret = 0;
- slot = path->slots[1];
- if (slot == 0)
- return 1;
- if (!path->nodes[1])
- return 1;
- right_nritems = btrfs_header_nritems(right);
- if (right_nritems == 0)
- return 1;
- btrfs_assert_tree_locked(path->nodes[1]);
- left = btrfs_read_node_slot(path->nodes[1], slot - 1);
- /*
- * slot - 1 is not valid or we fail to read the left node,
- * no big deal, just return.
- */
- if (IS_ERR(left))
- return 1;
- __btrfs_tree_lock(left, BTRFS_NESTING_LEFT);
- btrfs_set_lock_blocking_write(left);
- free_space = btrfs_leaf_free_space(left);
- if (free_space < data_size) {
- ret = 1;
- goto out;
- }
- /* cow and double check */
- ret = btrfs_cow_block(trans, root, left,
- path->nodes[1], slot - 1, &left,
- BTRFS_NESTING_LEFT_COW);
- if (ret) {
- /* we hit -ENOSPC, but it isn't fatal here */
- if (ret == -ENOSPC)
- ret = 1;
- goto out;
- }
- free_space = btrfs_leaf_free_space(left);
- if (free_space < data_size) {
- ret = 1;
- goto out;
- }
- if (check_sibling_keys(left, right)) {
- ret = -EUCLEAN;
- goto out;
- }
- return __push_leaf_left(path, min_data_size,
- empty, left, free_space, right_nritems,
- max_slot);
- out:
- btrfs_tree_unlock(left);
- free_extent_buffer(left);
- return ret;
- }
- /*
- * split the path's leaf in two, making sure there is at least data_size
- * available for the resulting leaf level of the path.
- */
- static noinline void copy_for_split(struct btrfs_trans_handle *trans,
- struct btrfs_path *path,
- struct extent_buffer *l,
- struct extent_buffer *right,
- int slot, int mid, int nritems)
- {
- struct btrfs_fs_info *fs_info = trans->fs_info;
- int data_copy_size;
- int rt_data_off;
- int i;
- struct btrfs_disk_key disk_key;
- struct btrfs_map_token token;
- nritems = nritems - mid;
- btrfs_set_header_nritems(right, nritems);
- data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(l);
- copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
- btrfs_item_nr_offset(mid),
- nritems * sizeof(struct btrfs_item));
- copy_extent_buffer(right, l,
- BTRFS_LEAF_DATA_OFFSET + BTRFS_LEAF_DATA_SIZE(fs_info) -
- data_copy_size, BTRFS_LEAF_DATA_OFFSET +
- leaf_data_end(l), data_copy_size);
- rt_data_off = BTRFS_LEAF_DATA_SIZE(fs_info) - btrfs_item_end_nr(l, mid);
- btrfs_init_map_token(&token, right);
- for (i = 0; i < nritems; i++) {
- struct btrfs_item *item = btrfs_item_nr(i);
- u32 ioff;
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item, ioff + rt_data_off);
- }
- btrfs_set_header_nritems(l, mid);
- btrfs_item_key(right, &disk_key, 0);
- insert_ptr(trans, path, &disk_key, right->start, path->slots[1] + 1, 1);
- btrfs_mark_buffer_dirty(right);
- btrfs_mark_buffer_dirty(l);
- BUG_ON(path->slots[0] != slot);
- if (mid <= slot) {
- btrfs_tree_unlock(path->nodes[0]);
- free_extent_buffer(path->nodes[0]);
- path->nodes[0] = right;
- path->slots[0] -= mid;
- path->slots[1] += 1;
- } else {
- btrfs_tree_unlock(right);
- free_extent_buffer(right);
- }
- BUG_ON(path->slots[0] < 0);
- }
- /*
- * double splits happen when we need to insert a big item in the middle
- * of a leaf. A double split can leave us with 3 mostly empty leaves:
- * leaf: [ slots 0 - N] [ our target ] [ N + 1 - total in leaf ]
- * A B C
- *
- * We avoid this by trying to push the items on either side of our target
- * into the adjacent leaves. If all goes well we can avoid the double split
- * completely.
- */
- static noinline int push_for_double_split(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path,
- int data_size)
- {
- int ret;
- int progress = 0;
- int slot;
- u32 nritems;
- int space_needed = data_size;
- slot = path->slots[0];
- if (slot < btrfs_header_nritems(path->nodes[0]))
- space_needed -= btrfs_leaf_free_space(path->nodes[0]);
- /*
- * try to push all the items after our slot into the
- * right leaf
- */
- ret = push_leaf_right(trans, root, path, 1, space_needed, 0, slot);
- if (ret < 0)
- return ret;
- if (ret == 0)
- progress++;
- nritems = btrfs_header_nritems(path->nodes[0]);
- /*
- * our goal is to get our slot at the start or end of a leaf. If
- * we've done so we're done
- */
- if (path->slots[0] == 0 || path->slots[0] == nritems)
- return 0;
- if (btrfs_leaf_free_space(path->nodes[0]) >= data_size)
- return 0;
- /* try to push all the items before our slot into the next leaf */
- slot = path->slots[0];
- space_needed = data_size;
- if (slot > 0)
- space_needed -= btrfs_leaf_free_space(path->nodes[0]);
- ret = push_leaf_left(trans, root, path, 1, space_needed, 0, slot);
- if (ret < 0)
- return ret;
- if (ret == 0)
- progress++;
- if (progress)
- return 0;
- return 1;
- }
- /*
- * split the path's leaf in two, making sure there is at least data_size
- * available for the resulting leaf level of the path.
- *
- * returns 0 if all went well and < 0 on failure.
- */
- static noinline int split_leaf(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- 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;
- struct btrfs_fs_info *fs_info = root->fs_info;
- int ret = 0;
- int wret;
- int split;
- int num_doubles = 0;
- int tried_avoid_double = 0;
- l = path->nodes[0];
- slot = path->slots[0];
- if (extend && data_size + btrfs_item_size_nr(l, slot) +
- sizeof(struct btrfs_item) > BTRFS_LEAF_DATA_SIZE(fs_info))
- return -EOVERFLOW;
- /* first try to make some room by pushing left and right */
- if (data_size && path->nodes[1]) {
- int space_needed = data_size;
- if (slot < btrfs_header_nritems(l))
- space_needed -= btrfs_leaf_free_space(l);
- wret = push_leaf_right(trans, root, path, space_needed,
- space_needed, 0, 0);
- if (wret < 0)
- return wret;
- if (wret) {
- space_needed = data_size;
- if (slot > 0)
- space_needed -= btrfs_leaf_free_space(l);
- wret = push_leaf_left(trans, root, path, space_needed,
- space_needed, 0, (u32)-1);
- 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(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(fs_info)) {
- if (data_size && !tried_avoid_double)
- goto push_for_double;
- split = 2;
- }
- }
- }
- } else {
- if (leaf_space_used(l, 0, mid) + data_size >
- BTRFS_LEAF_DATA_SIZE(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(fs_info)) {
- if (data_size && !tried_avoid_double)
- goto push_for_double;
- split = 2;
- }
- }
- }
- }
- if (split == 0)
- btrfs_cpu_key_to_disk(&disk_key, ins_key);
- else
- btrfs_item_key(l, &disk_key, mid);
- /*
- * We have to about BTRFS_NESTING_NEW_ROOT here if we've done a double
- * split, because we're only allowed to have MAX_LOCKDEP_SUBCLASSES
- * subclasses, which is 8 at the time of this patch, and we've maxed it
- * out. In the future we could add a
- * BTRFS_NESTING_SPLIT_THE_SPLITTENING if we need to, but for now just
- * use BTRFS_NESTING_NEW_ROOT.
- */
- right = alloc_tree_block_no_bg_flush(trans, root, 0, &disk_key, 0,
- l->start, 0, num_doubles ?
- BTRFS_NESTING_NEW_ROOT :
- BTRFS_NESTING_SPLIT);
- if (IS_ERR(right))
- return PTR_ERR(right);
- root_add_used(root, fs_info->nodesize);
- if (split == 0) {
- if (mid <= slot) {
- btrfs_set_header_nritems(right, 0);
- insert_ptr(trans, path, &disk_key,
- right->start, path->slots[1] + 1, 1);
- btrfs_tree_unlock(path->nodes[0]);
- free_extent_buffer(path->nodes[0]);
- path->nodes[0] = right;
- path->slots[0] = 0;
- path->slots[1] += 1;
- } else {
- btrfs_set_header_nritems(right, 0);
- insert_ptr(trans, path, &disk_key,
- right->start, path->slots[1], 1);
- btrfs_tree_unlock(path->nodes[0]);
- free_extent_buffer(path->nodes[0]);
- path->nodes[0] = right;
- path->slots[0] = 0;
- if (path->slots[1] == 0)
- fixup_low_keys(path, &disk_key, 1);
- }
- /*
- * We create a new leaf 'right' for the required ins_len and
- * we'll do btrfs_mark_buffer_dirty() on this leaf after copying
- * the content of ins_len to 'right'.
- */
- return ret;
- }
- copy_for_split(trans, path, l, right, slot, mid, nritems);
- if (split == 2) {
- BUG_ON(num_doubles != 0);
- num_doubles++;
- goto again;
- }
- return 0;
- push_for_double:
- push_for_double_split(trans, root, path, data_size);
- tried_avoid_double = 1;
- if (btrfs_leaf_free_space(path->nodes[0]) >= data_size)
- return 0;
- goto again;
- }
- static noinline int setup_leaf_for_split(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path, int ins_len)
- {
- struct btrfs_key key;
- struct extent_buffer *leaf;
- struct btrfs_file_extent_item *fi;
- u64 extent_len = 0;
- u32 item_size;
- int ret;
- leaf = path->nodes[0];
- btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
- BUG_ON(key.type != BTRFS_EXTENT_DATA_KEY &&
- key.type != BTRFS_EXTENT_CSUM_KEY);
- if (btrfs_leaf_free_space(leaf) >= ins_len)
- return 0;
- item_size = btrfs_item_size_nr(leaf, path->slots[0]);
- if (key.type == BTRFS_EXTENT_DATA_KEY) {
- fi = btrfs_item_ptr(leaf, path->slots[0],
- struct btrfs_file_extent_item);
- extent_len = btrfs_file_extent_num_bytes(leaf, fi);
- }
- btrfs_release_path(path);
- path->keep_locks = 1;
- path->search_for_split = 1;
- ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
- path->search_for_split = 0;
- if (ret > 0)
- ret = -EAGAIN;
- if (ret < 0)
- goto err;
- ret = -EAGAIN;
- leaf = path->nodes[0];
- /* if our item isn't there, return now */
- if (item_size != btrfs_item_size_nr(leaf, path->slots[0]))
- goto err;
- /* the leaf has changed, it now has room. return now */
- if (btrfs_leaf_free_space(path->nodes[0]) >= ins_len)
- goto err;
- if (key.type == BTRFS_EXTENT_DATA_KEY) {
- fi = btrfs_item_ptr(leaf, path->slots[0],
- struct btrfs_file_extent_item);
- if (extent_len != btrfs_file_extent_num_bytes(leaf, fi))
- goto err;
- }
- btrfs_set_path_blocking(path);
- ret = split_leaf(trans, root, &key, path, ins_len, 1);
- if (ret)
- goto err;
- path->keep_locks = 0;
- btrfs_unlock_up_safe(path, 1);
- return 0;
- err:
- path->keep_locks = 0;
- return ret;
- }
- static noinline int split_item(struct btrfs_path *path,
- const struct btrfs_key *new_key,
- unsigned long split_offset)
- {
- struct extent_buffer *leaf;
- struct btrfs_item *item;
- struct btrfs_item *new_item;
- int slot;
- char *buf;
- u32 nritems;
- u32 item_size;
- u32 orig_offset;
- struct btrfs_disk_key disk_key;
- leaf = path->nodes[0];
- BUG_ON(btrfs_leaf_free_space(leaf) < sizeof(struct btrfs_item));
- btrfs_set_path_blocking(path);
- item = btrfs_item_nr(path->slots[0]);
- orig_offset = btrfs_item_offset(leaf, item);
- item_size = btrfs_item_size(leaf, item);
- buf = kmalloc(item_size, GFP_NOFS);
- if (!buf)
- return -ENOMEM;
- read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
- path->slots[0]), item_size);
- slot = path->slots[0] + 1;
- nritems = btrfs_header_nritems(leaf);
- if (slot != nritems) {
- /* shift the items */
- memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + 1),
- btrfs_item_nr_offset(slot),
- (nritems - slot) * sizeof(struct btrfs_item));
- }
- btrfs_cpu_key_to_disk(&disk_key, new_key);
- btrfs_set_item_key(leaf, &disk_key, slot);
- new_item = btrfs_item_nr(slot);
- btrfs_set_item_offset(leaf, new_item, orig_offset);
- btrfs_set_item_size(leaf, new_item, item_size - split_offset);
- btrfs_set_item_offset(leaf, item,
- orig_offset + item_size - split_offset);
- btrfs_set_item_size(leaf, item, split_offset);
- btrfs_set_header_nritems(leaf, nritems + 1);
- /* write the data for the start of the original item */
- write_extent_buffer(leaf, buf,
- btrfs_item_ptr_offset(leaf, path->slots[0]),
- split_offset);
- /* write the data for the new item */
- write_extent_buffer(leaf, buf + split_offset,
- btrfs_item_ptr_offset(leaf, slot),
- item_size - split_offset);
- btrfs_mark_buffer_dirty(leaf);
- BUG_ON(btrfs_leaf_free_space(leaf) < 0);
- kfree(buf);
- return 0;
- }
- /*
- * This function splits a single item into two items,
- * giving 'new_key' to the new item and splitting the
- * old one at split_offset (from the start of the item).
- *
- * The path may be released by this operation. After
- * the split, the path is pointing to the old item. The
- * new item is going to be in the same node as the old one.
- *
- * Note, the item being split must be smaller enough to live alone on
- * a tree block with room for one extra struct btrfs_item
- *
- * This allows us to split the item in place, keeping a lock on the
- * leaf the entire time.
- */
- int btrfs_split_item(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path,
- const struct btrfs_key *new_key,
- unsigned long split_offset)
- {
- int ret;
- ret = setup_leaf_for_split(trans, root, path,
- sizeof(struct btrfs_item));
- if (ret)
- return ret;
- ret = split_item(path, new_key, split_offset);
- return ret;
- }
- /*
- * This function duplicate a item, giving 'new_key' to the new item.
- * It guarantees both items live in the same tree leaf and the new item
- * is contiguous with the original item.
- *
- * This allows us to split file extent in place, keeping a lock on the
- * leaf the entire time.
- */
- int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path,
- const struct btrfs_key *new_key)
- {
- struct extent_buffer *leaf;
- int ret;
- u32 item_size;
- leaf = path->nodes[0];
- item_size = btrfs_item_size_nr(leaf, path->slots[0]);
- ret = setup_leaf_for_split(trans, root, path,
- item_size + sizeof(struct btrfs_item));
- if (ret)
- return ret;
- path->slots[0]++;
- setup_items_for_insert(root, path, new_key, &item_size, 1);
- leaf = path->nodes[0];
- memcpy_extent_buffer(leaf,
- btrfs_item_ptr_offset(leaf, path->slots[0]),
- btrfs_item_ptr_offset(leaf, path->slots[0] - 1),
- item_size);
- return 0;
- }
- /*
- * make the item pointed to by the path smaller. new_size indicates
- * how small to make it, and from_end tells us if we just chop bytes
- * off the end of the item or if we shift the item to chop bytes off
- * the front.
- */
- void btrfs_truncate_item(struct btrfs_path *path, u32 new_size, int from_end)
- {
- int slot;
- struct extent_buffer *leaf;
- struct btrfs_item *item;
- u32 nritems;
- unsigned int data_end;
- unsigned int old_data_start;
- unsigned int old_size;
- unsigned int size_diff;
- int i;
- struct btrfs_map_token token;
- leaf = path->nodes[0];
- slot = path->slots[0];
- old_size = btrfs_item_size_nr(leaf, slot);
- if (old_size == new_size)
- return;
- nritems = btrfs_header_nritems(leaf);
- data_end = leaf_data_end(leaf);
- old_data_start = btrfs_item_offset_nr(leaf, slot);
- size_diff = old_size - new_size;
- BUG_ON(slot < 0);
- BUG_ON(slot >= nritems);
- /*
- * item0..itemN ... dataN.offset..dataN.size .. data0.size
- */
- /* first correct the data pointers */
- btrfs_init_map_token(&token, leaf);
- for (i = slot; i < nritems; i++) {
- u32 ioff;
- item = btrfs_item_nr(i);
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item, ioff + size_diff);
- }
- /* shift the data */
- if (from_end) {
- memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
- data_end + size_diff, BTRFS_LEAF_DATA_OFFSET +
- 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,
- BTRFS_FILE_EXTENT_INLINE_DATA_START);
- }
- }
- memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
- data_end + size_diff, BTRFS_LEAF_DATA_OFFSET +
- 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);
- }
- item = btrfs_item_nr(slot);
- btrfs_set_item_size(leaf, item, new_size);
- btrfs_mark_buffer_dirty(leaf);
- if (btrfs_leaf_free_space(leaf) < 0) {
- btrfs_print_leaf(leaf);
- BUG();
- }
- }
- /*
- * make the item pointed to by the path bigger, data_size is the added size.
- */
- void btrfs_extend_item(struct btrfs_path *path, u32 data_size)
- {
- int slot;
- struct extent_buffer *leaf;
- struct btrfs_item *item;
- u32 nritems;
- unsigned int data_end;
- unsigned int old_data;
- unsigned int old_size;
- int i;
- struct btrfs_map_token token;
- 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_end_nr(leaf, slot);
- BUG_ON(slot < 0);
- if (slot >= nritems) {
- btrfs_print_leaf(leaf);
- btrfs_crit(leaf->fs_info, "slot %d too large, nritems %d",
- slot, nritems);
- BUG();
- }
- /*
- * item0..itemN ... dataN.offset..dataN.size .. data0.size
- */
- /* first correct the data pointers */
- btrfs_init_map_token(&token, leaf);
- for (i = slot; i < nritems; i++) {
- u32 ioff;
- item = btrfs_item_nr(i);
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item, ioff - data_size);
- }
- /* shift the data */
- memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
- data_end - data_size, BTRFS_LEAF_DATA_OFFSET +
- data_end, old_data - data_end);
- data_end = old_data;
- old_size = btrfs_item_size_nr(leaf, slot);
- item = btrfs_item_nr(slot);
- btrfs_set_item_size(leaf, item, old_size + data_size);
- btrfs_mark_buffer_dirty(leaf);
- if (btrfs_leaf_free_space(leaf) < 0) {
- btrfs_print_leaf(leaf);
- BUG();
- }
- }
- /**
- * setup_items_for_insert - Helper called before inserting one or more items
- * to a leaf. Main purpose is to save stack depth by doing the bulk of the work
- * in a function that doesn't call btrfs_search_slot
- *
- * @root: root we are inserting items to
- * @path: points to the leaf/slot where we are going to insert new items
- * @cpu_key: array of keys for items to be inserted
- * @data_size: size of the body of each item we are going to insert
- * @nr: size of @cpu_key/@data_size arrays
- */
- void setup_items_for_insert(struct btrfs_root *root, struct btrfs_path *path,
- const struct btrfs_key *cpu_key, u32 *data_size,
- int nr)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct btrfs_item *item;
- int i;
- u32 nritems;
- unsigned int data_end;
- struct btrfs_disk_key disk_key;
- struct extent_buffer *leaf;
- int slot;
- struct btrfs_map_token token;
- u32 total_size;
- u32 total_data = 0;
- for (i = 0; i < nr; i++)
- total_data += data_size[i];
- total_size = total_data + (nr * sizeof(struct btrfs_item));
- if (path->slots[0] == 0) {
- btrfs_cpu_key_to_disk(&disk_key, cpu_key);
- fixup_low_keys(path, &disk_key, 1);
- }
- btrfs_unlock_up_safe(path, 1);
- leaf = path->nodes[0];
- slot = path->slots[0];
- nritems = btrfs_header_nritems(leaf);
- data_end = leaf_data_end(leaf);
- if (btrfs_leaf_free_space(leaf) < total_size) {
- btrfs_print_leaf(leaf);
- btrfs_crit(fs_info, "not enough freespace need %u have %d",
- total_size, btrfs_leaf_free_space(leaf));
- BUG();
- }
- btrfs_init_map_token(&token, leaf);
- if (slot != nritems) {
- unsigned int old_data = btrfs_item_end_nr(leaf, slot);
- if (old_data < data_end) {
- btrfs_print_leaf(leaf);
- btrfs_crit(fs_info,
- "item at slot %d with data offset %u beyond data end of leaf %u",
- slot, old_data, data_end);
- BUG();
- }
- /*
- * item0..itemN ... dataN.offset..dataN.size .. data0.size
- */
- /* first correct the data pointers */
- for (i = slot; i < nritems; i++) {
- u32 ioff;
- item = btrfs_item_nr(i);
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item,
- ioff - total_data);
- }
- /* shift the items */
- memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot + nr),
- btrfs_item_nr_offset(slot),
- (nritems - slot) * sizeof(struct btrfs_item));
- /* shift the data */
- memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
- data_end - total_data, BTRFS_LEAF_DATA_OFFSET +
- data_end, old_data - data_end);
- data_end = old_data;
- }
- /* setup the item for the new data */
- for (i = 0; i < nr; i++) {
- btrfs_cpu_key_to_disk(&disk_key, cpu_key + i);
- btrfs_set_item_key(leaf, &disk_key, slot + i);
- item = btrfs_item_nr(slot + i);
- data_end -= data_size[i];
- btrfs_set_token_item_offset(&token, item, data_end);
- btrfs_set_token_item_size(&token, item, data_size[i]);
- }
- btrfs_set_header_nritems(leaf, nritems + nr);
- btrfs_mark_buffer_dirty(leaf);
- if (btrfs_leaf_free_space(leaf) < 0) {
- btrfs_print_leaf(leaf);
- BUG();
- }
- }
- /*
- * Given a key and some data, insert items into the tree.
- * This does all the path init required, making room in the tree if needed.
- */
- int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path,
- const struct btrfs_key *cpu_key, u32 *data_size,
- int nr)
- {
- int ret = 0;
- int slot;
- int i;
- u32 total_size = 0;
- u32 total_data = 0;
- for (i = 0; i < nr; i++)
- total_data += data_size[i];
- total_size = total_data + (nr * sizeof(struct btrfs_item));
- ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
- if (ret == 0)
- return -EEXIST;
- if (ret < 0)
- return ret;
- slot = path->slots[0];
- BUG_ON(slot < 0);
- setup_items_for_insert(root, path, cpu_key, data_size, nr);
- return 0;
- }
- /*
- * Given a key and some data, insert an item into the tree.
- * This does all the path init required, making room in the tree if needed.
- */
- int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
- 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.
- *
- * the tree should have been previously balanced so the deletion does not
- * empty a node.
- */
- static void del_ptr(struct btrfs_root *root, struct btrfs_path *path,
- int level, int slot)
- {
- struct extent_buffer *parent = path->nodes[level];
- u32 nritems;
- int ret;
- nritems = btrfs_header_nritems(parent);
- if (slot != nritems - 1) {
- if (level) {
- ret = tree_mod_log_insert_move(parent, slot, slot + 1,
- nritems - slot - 1);
- BUG_ON(ret < 0);
- }
- memmove_extent_buffer(parent,
- btrfs_node_key_ptr_offset(slot),
- btrfs_node_key_ptr_offset(slot + 1),
- sizeof(struct btrfs_key_ptr) *
- (nritems - slot - 1));
- } else if (level) {
- ret = tree_mod_log_insert_key(parent, slot, MOD_LOG_KEY_REMOVE,
- GFP_NOFS);
- BUG_ON(ret < 0);
- }
- 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);
- }
- /*
- * a helper function to delete the leaf pointed to by path->slots[1] and
- * path->nodes[1].
- *
- * This deletes the pointer in path->nodes[1] and frees the leaf
- * block extent. zero is returned if it all worked out, < 0 otherwise.
- *
- * The path must have already been setup for deleting the leaf, including
- * all the proper balancing. path->nodes[1] must be locked.
- */
- static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
- struct btrfs_path *path,
- struct extent_buffer *leaf)
- {
- WARN_ON(btrfs_header_generation(leaf) != trans->transid);
- del_ptr(root, path, 1, path->slots[1]);
- /*
- * btrfs_free_extent is expensive, we want to make sure we
- * aren't holding any locks when we call it
- */
- btrfs_unlock_up_safe(path, 0);
- root_sub_used(root, leaf->len);
- atomic_inc(&leaf->refs);
- btrfs_free_tree_block(trans, root, leaf, 0, 1);
- free_extent_buffer_stale(leaf);
- }
- /*
- * delete the item at the leaf level in path. If that empties
- * the leaf, remove it from the tree
- */
- int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
- struct btrfs_path *path, int slot, int nr)
- {
- struct btrfs_fs_info *fs_info = root->fs_info;
- struct extent_buffer *leaf;
- struct btrfs_item *item;
- u32 last_off;
- u32 dsize = 0;
- int ret = 0;
- int wret;
- int i;
- u32 nritems;
- leaf = path->nodes[0];
- last_off = btrfs_item_offset_nr(leaf, slot + nr - 1);
- for (i = 0; i < nr; i++)
- dsize += btrfs_item_size_nr(leaf, slot + i);
- nritems = btrfs_header_nritems(leaf);
- if (slot + nr != nritems) {
- int data_end = leaf_data_end(leaf);
- struct btrfs_map_token token;
- memmove_extent_buffer(leaf, BTRFS_LEAF_DATA_OFFSET +
- data_end + dsize,
- BTRFS_LEAF_DATA_OFFSET + data_end,
- last_off - data_end);
- btrfs_init_map_token(&token, leaf);
- for (i = slot + nr; i < nritems; i++) {
- u32 ioff;
- item = btrfs_item_nr(i);
- ioff = btrfs_token_item_offset(&token, item);
- btrfs_set_token_item_offset(&token, item, ioff + dsize);
- }
- memmove_extent_buffer(leaf, btrfs_item_nr_offset(slot),
- btrfs_item_nr_offset(slot + nr),
- sizeof(struct btrfs_item) *
- (nritems - slot - nr));
- }
- btrfs_set_header_nritems(leaf, nritems - nr);
- nritems -= nr;
- /* delete the leaf if we've emptied it */
- if (nritems == 0) {
- if (leaf == root->node) {
- btrfs_set_header_level(leaf, 0);
- } else {
- btrfs_set_path_blocking(path);
- btrfs_clean_tree_block(leaf);
- btrfs_del_leaf(trans, root, path, leaf);
- }
- } else {
- int used = leaf_space_used(leaf, 0, nritems);
- if (slot == 0) {
- struct btrfs_disk_key disk_key;
- btrfs_item_key(leaf, &disk_key, 0);
- fixup_low_keys(path, &disk_key, 1);
- }
- /* delete the leaf if it is mostly empty */
- if (used < BTRFS_LEAF_DATA_SIZE(fs_info) / 3) {
- /* push_leaf_left fixes the path.
- * make sure the path still points to our leaf
- * for possible call to del_ptr below
- */
- slot = path->slots[1];
- atomic_inc(&leaf->refs);
- btrfs_set_path_blocking(path);
- wret = push_leaf_left(trans, root, path, 1, 1,
- 1, (u32)-1);
- if (wret < 0 && wret != -ENOSPC)
- ret = wret;
- if (path->nodes[0] == leaf &&
- btrfs_header_nritems(leaf)) {
- wret = push_leaf_right(trans, root, path, 1,
- 1, 1, 0);
- if (wret < 0 && wret != -ENOSPC)
- ret = wret;
- }
- if (btrfs_header_nritems(leaf) == 0) {
- path->slots[1] = slot;
- btrfs_del_leaf(trans, root, path, leaf);
- free_extent_buffer(leaf);
- ret = 0;
- } else {
- /* if we're still in the path, make sure
- * we're dirty. Otherwise, one of the
- * push_leaf functions must have already
- * dirtied this buffer
- */
- if (path->nodes[0] == leaf)
- btrfs_mark_buffer_dirty(leaf);
- free_extent_buffer(leaf);
- }
- } else {
- btrfs_mark_buffer_dirty(leaf);
- }
- }
- return ret;
- }
- /*
- * search the tree again to find a leaf with lesser keys
- * returns 0 if it found something or 1 if there are no lesser leaves.
- * returns < 0 on io errors.
- *
- * This may release the path, and so you may lose any locks held at the
- * time you call it.
- */
- int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path)
- {
- struct btrfs_key key;
- struct btrfs_disk_key found_key;
- int ret;
- btrfs_item_key_to_cpu(path->nodes[0], &key, 0);
- if (key.offset > 0) {
- key.offset--;
- } else if (key.type > 0) {
- key.type--;
- key.offset = (u64)-1;
- } else if (key.objectid > 0) {
- key.objectid--;
- key.type = (u8)-1;
- key.offset = (u64)-1;
- } else {
- return 1;
- }
- btrfs_release_path(path);
- ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
- if (ret < 0)
- return ret;
- btrfs_item_key(path->nodes[0], &found_key, 0);
- ret = comp_keys(&found_key, &key);
- /*
- * We might have had an item with the previous key in the tree right
- * before we released our path. And after we released our path, that
- * item might have been pushed to the first slot (0) of the leaf we
- * were holding due to a tree balance. Alternatively, an item with the
- * previous key can exist as the only element of a leaf (big fat item).
- * Therefore account for these 2 cases, so that our callers (like
- * btrfs_previous_item) don't miss an existing item with a key matching
- * the previous key we computed above.
- */
- if (ret <= 0)
- return 0;
- return 1;
- }
- /*
- * A helper function to walk down the tree starting at min_key, and looking
- * for nodes or leaves that are have a minimum transaction id.
- * This is used by the btree defrag code, and tree logging
- *
- * This does not cow, but it does stuff the starting key it finds back
- * into min_key, so you can call btrfs_search_slot with cow=1 on the
- * key and get a writable path.
- *
- * This honors path->lowest_level to prevent descent past a given level
- * of the tree.
- *
- * min_trans indicates the oldest transaction that you are interested
- * in walking through. Any nodes or leaves older than min_trans are
- * skipped over (without reading them).
- *
- * returns zero if something useful was found, < 0 on error and 1 if there
- * was nothing in the tree that matched the search criteria.
- */
- int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
- struct btrfs_path *path,
- u64 min_trans)
- {
- struct extent_buffer *cur;
- struct btrfs_key found_key;
- int slot;
- int sret;
- u32 nritems;
- int level;
- int ret = 1;
- int keep_locks = path->keep_locks;
- path->keep_locks = 1;
- again:
- cur = btrfs_read_lock_root_node(root);
- level = btrfs_header_level(cur);
- WARN_ON(path->nodes[level]);
- path->nodes[level] = cur;
- path->locks[level] = BTRFS_READ_LOCK;
- if (btrfs_header_generation(cur) < min_trans) {
- ret = 1;
- goto out;
- }
- while (1) {
- nritems = btrfs_header_nritems(cur);
- level = btrfs_header_level(cur);
- sret = btrfs_bin_search(cur, min_key, &slot);
- if (sret < 0) {
- ret = sret;
- goto out;
- }
- /* at the lowest level, we're done, setup the path and exit */
- if (level == path->lowest_level) {
- if (slot >= nritems)
- goto find_next_key;
- ret = 0;
- path->slots[level] = slot;
- btrfs_item_key_to_cpu(cur, &found_key, slot);
- goto out;
- }
- if (sret && slot > 0)
- slot--;
- /*
- * check this node pointer against the min_trans parameters.
- * If it is too old, skip to the next one.
- */
- while (slot < nritems) {
- u64 gen;
- gen = btrfs_node_ptr_generation(cur, slot);
- if (gen < min_trans) {
- slot++;
- continue;
- }
- break;
- }
- find_next_key:
- /*
- * we didn't find a candidate key in this node, walk forward
- * and find another one
- */
- if (slot >= nritems) {
- path->slots[level] = slot;
- btrfs_set_path_blocking(path);
- sret = btrfs_find_next_key(root, path, min_key, level,
- min_trans);
- if (sret == 0) {
- btrfs_release_path(path);
- goto again;
- } else {
- goto out;
- }
- }
- /* save our key for returning back */
- btrfs_node_key_to_cpu(cur, &found_key, slot);
- path->slots[level] = slot;
- if (level == path->lowest_level) {
- ret = 0;
- goto out;
- }
- btrfs_set_path_blocking(path);
- cur = btrfs_read_node_slot(cur, slot);
- if (IS_ERR(cur)) {
- ret = PTR_ERR(cur);
- goto out;
- }
- btrfs_tree_read_lock(cur);
- path->locks[level - 1] = BTRFS_READ_LOCK;
- path->nodes[level - 1] = cur;
- unlock_up(path, level, 1, 0, NULL);
- }
- out:
- path->keep_locks = keep_locks;
- if (ret == 0) {
- btrfs_unlock_up_safe(path, path->lowest_level + 1);
- btrfs_set_path_blocking(path);
- memcpy(min_key, &found_key, sizeof(found_key));
- }
- return ret;
- }
- /*
- * this is similar to btrfs_next_leaf, but does not try to preserve
- * and fixup the path. It looks for and returns the next key in the
- * tree based on the current path and the min_trans parameters.
- *
- * 0 is returned if another key is found, < 0 if there are any errors
- * and 1 is returned if there are no higher keys in the tree
- *
- * path->keep_locks should be set to 1 on the search made before
- * calling this function.
- */
- int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
- struct btrfs_key *key, int level, u64 min_trans)
- {
- int slot;
- struct extent_buffer *c;
- WARN_ON(!path->keep_locks && !path->skip_locking);
- while (level < BTRFS_MAX_LEVEL) {
- if (!path->nodes[level])
- return 1;
- slot = path->slots[level] + 1;
- c = path->nodes[level];
- next:
- if (slot >= btrfs_header_nritems(c)) {
- int ret;
- int orig_lowest;
- struct btrfs_key cur_key;
- if (level + 1 >= BTRFS_MAX_LEVEL ||
- !path->nodes[level + 1])
- return 1;
- if (path->locks[level + 1] || path->skip_locking) {
- level++;
- continue;
- }
- slot = btrfs_header_nritems(c) - 1;
- if (level == 0)
- btrfs_item_key_to_cpu(c, &cur_key, slot);
- else
- btrfs_node_key_to_cpu(c, &cur_key, slot);
- orig_lowest = path->lowest_level;
- btrfs_release_path(path);
- path->lowest_level = level;
- ret = btrfs_search_slot(NULL, root, &cur_key, path,
- 0, 0);
- path->lowest_level = orig_lowest;
- if (ret < 0)
- return ret;
- c = path->nodes[level];
- slot = path->slots[level];
- if (ret == 0)
- slot++;
- goto next;
- }
- if (level == 0)
- btrfs_item_key_to_cpu(c, key, slot);
- else {
- u64 gen = btrfs_node_ptr_generation(c, slot);
- if (gen < min_trans) {
- slot++;
- goto next;
- }
- btrfs_node_key_to_cpu(c, key, slot);
- }
- return 0;
- }
- return 1;
- }
- /*
- * search the tree again to find a leaf with greater keys
- * returns 0 if it found something or 1 if there are no greater leaves.
- * returns < 0 on io errors.
- */
- int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
- {
- return btrfs_next_old_leaf(root, path, 0);
- }
- int btrfs_next_old_leaf(struct btrfs_root *root, struct btrfs_path *path,
- u64 time_seq)
- {
- int slot;
- int level;
- struct extent_buffer *c;
- struct extent_buffer *next;
- struct btrfs_key key;
- u32 nritems;
- int ret;
- int old_spinning = path->leave_spinning;
- int next_rw_lock = 0;
- nritems = btrfs_header_nritems(path->nodes[0]);
- if (nritems == 0)
- return 1;
- btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
- again:
- level = 1;
- next = NULL;
- next_rw_lock = 0;
- btrfs_release_path(path);
- path->keep_locks = 1;
- path->leave_spinning = 1;
- if (time_seq)
- ret = btrfs_search_old_slot(root, &key, path, time_seq);
- else
- ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
- path->keep_locks = 0;
- if (ret < 0)
- return ret;
- nritems = btrfs_header_nritems(path->nodes[0]);
- /*
- * by releasing the path above we dropped all our locks. A balance
- * could have added more items next to the key that used to be
- * at the very end of the block. So, check again here and
- * advance the path if there are now more items available.
- */
- if (nritems > 0 && path->slots[0] < nritems - 1) {
- if (ret == 0)
- path->slots[0]++;
- ret = 0;
- goto done;
- }
- /*
- * So the above check misses one case:
- * - after releasing the path above, someone has removed the item that
- * used to be at the very end of the block, and balance between leafs
- * gets another one with bigger key.offset to replace it.
- *
- * This one should be returned as well, or we can get leaf corruption
- * later(esp. in __btrfs_drop_extents()).
- *
- * And a bit more explanation about this check,
- * with ret > 0, the key isn't found, the path points to the slot
- * where it should be inserted, so the path->slots[0] item must be the
- * bigger one.
- */
- if (nritems > 0 && ret > 0 && path->slots[0] == nritems - 1) {
- ret = 0;
- goto done;
- }
- while (level < BTRFS_MAX_LEVEL) {
- if (!path->nodes[level]) {
- ret = 1;
- goto done;
- }
- slot = path->slots[level] + 1;
- c = path->nodes[level];
- if (slot >= btrfs_header_nritems(c)) {
- level++;
- if (level == BTRFS_MAX_LEVEL) {
- ret = 1;
- goto done;
- }
- continue;
- }
- if (next) {
- btrfs_tree_unlock_rw(next, next_rw_lock);
- free_extent_buffer(next);
- }
- next = c;
- next_rw_lock = path->locks[level];
- ret = read_block_for_search(root, path, &next, level,
- slot, &key);
- if (ret == -EAGAIN)
- goto again;
- if (ret < 0) {
- btrfs_release_path(path);
- goto done;
- }
- if (!path->skip_locking) {
- ret = btrfs_try_tree_read_lock(next);
- if (!ret && time_seq) {
- /*
- * If we don't get the lock, we may be racing
- * with push_leaf_left, holding that lock while
- * itself waiting for the leaf we've currently
- * locked. To solve this situation, we give up
- * on our lock and cycle.
- */
- free_extent_buffer(next);
- btrfs_release_path(path);
- cond_resched();
- goto again;
- }
- if (!ret) {
- btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next,
- BTRFS_NESTING_RIGHT,
- path->recurse);
- }
- next_rw_lock = BTRFS_READ_LOCK;
- }
- break;
- }
- path->slots[level] = slot;
- while (1) {
- level--;
- c = path->nodes[level];
- if (path->locks[level])
- btrfs_tree_unlock_rw(c, path->locks[level]);
- free_extent_buffer(c);
- path->nodes[level] = next;
- path->slots[level] = 0;
- if (!path->skip_locking)
- path->locks[level] = next_rw_lock;
- if (!level)
- break;
- ret = read_block_for_search(root, path, &next, level,
- 0, &key);
- if (ret == -EAGAIN)
- goto again;
- if (ret < 0) {
- btrfs_release_path(path);
- goto done;
- }
- if (!path->skip_locking) {
- ret = btrfs_try_tree_read_lock(next);
- if (!ret) {
- btrfs_set_path_blocking(path);
- __btrfs_tree_read_lock(next,
- BTRFS_NESTING_RIGHT,
- path->recurse);
- }
- next_rw_lock = BTRFS_READ_LOCK;
- }
- }
- ret = 0;
- done:
- unlock_up(path, 0, 1, 0, NULL);
- path->leave_spinning = old_spinning;
- if (!old_spinning)
- btrfs_set_path_blocking(path);
- return ret;
- }
- /*
- * this uses btrfs_prev_leaf to walk backwards in the tree, and keeps
- * searching until it gets past min_objectid or finds an item of 'type'
- *
- * returns 0 if something is found, 1 if nothing was found and < 0 on error
- */
- int btrfs_previous_item(struct btrfs_root *root,
- struct btrfs_path *path, u64 min_objectid,
- int type)
- {
- struct btrfs_key found_key;
- struct extent_buffer *leaf;
- u32 nritems;
- int ret;
- while (1) {
- if (path->slots[0] == 0) {
- btrfs_set_path_blocking(path);
- ret = btrfs_prev_leaf(root, path);
- if (ret != 0)
- return ret;
- } else {
- path->slots[0]--;
- }
- leaf = path->nodes[0];
- nritems = btrfs_header_nritems(leaf);
- if (nritems == 0)
- return 1;
- if (path->slots[0] == nritems)
- path->slots[0]--;
- btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
- if (found_key.objectid < min_objectid)
- break;
- if (found_key.type == type)
- return 0;
- if (found_key.objectid == min_objectid &&
- found_key.type < type)
- break;
- }
- return 1;
- }
- /*
- * search in extent tree to find a previous Metadata/Data extent item with
- * min objecitd.
- *
- * returns 0 if something is found, 1 if nothing was found and < 0 on error
- */
- int btrfs_previous_extent_item(struct btrfs_root *root,
- struct btrfs_path *path, u64 min_objectid)
- {
- struct btrfs_key found_key;
- struct extent_buffer *leaf;
- u32 nritems;
- int ret;
- while (1) {
- if (path->slots[0] == 0) {
- btrfs_set_path_blocking(path);
- ret = btrfs_prev_leaf(root, path);
- if (ret != 0)
- return ret;
- } else {
- path->slots[0]--;
- }
- leaf = path->nodes[0];
- nritems = btrfs_header_nritems(leaf);
- if (nritems == 0)
- return 1;
- if (path->slots[0] == nritems)
- path->slots[0]--;
- btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
- if (found_key.objectid < min_objectid)
- break;
- if (found_key.type == 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;
- }
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