diff options
Diffstat (limited to 'fs/btrfs/delayed-ref.c')
| -rw-r--r-- | fs/btrfs/delayed-ref.c | 1406 |
1 files changed, 1406 insertions, 0 deletions
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c new file mode 100644 index 000000000..8bc192923 --- /dev/null +++ b/fs/btrfs/delayed-ref.c @@ -0,0 +1,1406 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2009 Oracle. All rights reserved. + */ + +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/sort.h> +#include "messages.h" +#include "ctree.h" +#include "delayed-ref.h" +#include "extent-tree.h" +#include "transaction.h" +#include "qgroup.h" +#include "space-info.h" +#include "tree-mod-log.h" +#include "fs.h" + +struct kmem_cache *btrfs_delayed_ref_head_cachep; +struct kmem_cache *btrfs_delayed_ref_node_cachep; +struct kmem_cache *btrfs_delayed_extent_op_cachep; +/* + * delayed back reference update tracking. For subvolume trees + * we queue up extent allocations and backref maintenance for + * delayed processing. This avoids deep call chains where we + * add extents in the middle of btrfs_search_slot, and it allows + * us to buffer up frequently modified backrefs in an rb tree instead + * of hammering updates on the extent allocation tree. + */ + +bool btrfs_check_space_for_delayed_refs(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv; + struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; + bool ret = false; + u64 reserved; + + spin_lock(&global_rsv->lock); + reserved = global_rsv->reserved; + spin_unlock(&global_rsv->lock); + + /* + * Since the global reserve is just kind of magic we don't really want + * to rely on it to save our bacon, so if our size is more than the + * delayed_refs_rsv and the global rsv then it's time to think about + * bailing. + */ + spin_lock(&delayed_refs_rsv->lock); + reserved += delayed_refs_rsv->reserved; + if (delayed_refs_rsv->size >= reserved) + ret = true; + spin_unlock(&delayed_refs_rsv->lock); + return ret; +} + +/* + * Release a ref head's reservation. + * + * @fs_info: the filesystem + * @nr_refs: number of delayed refs to drop + * @nr_csums: number of csum items to drop + * + * Drops the delayed ref head's count from the delayed refs rsv and free any + * excess reservation we had. + */ +void btrfs_delayed_refs_rsv_release(struct btrfs_fs_info *fs_info, int nr_refs, int nr_csums) +{ + struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv; + u64 num_bytes; + u64 released; + + num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, nr_refs); + num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info, nr_csums); + + released = btrfs_block_rsv_release(fs_info, block_rsv, num_bytes, NULL); + if (released) + trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", + 0, released, 0); +} + +/* + * Adjust the size of the delayed refs rsv. + * + * This is to be called anytime we may have adjusted trans->delayed_ref_updates + * or trans->delayed_ref_csum_deletions, it'll calculate the additional size and + * add it to the delayed_refs_rsv. + */ +void btrfs_update_delayed_refs_rsv(struct btrfs_trans_handle *trans) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv; + struct btrfs_block_rsv *local_rsv = &trans->delayed_rsv; + u64 num_bytes; + u64 reserved_bytes; + + if (btrfs_is_testing(fs_info)) + return; + + num_bytes = btrfs_calc_delayed_ref_bytes(fs_info, trans->delayed_ref_updates); + num_bytes += btrfs_calc_delayed_ref_csum_bytes(fs_info, + trans->delayed_ref_csum_deletions); + + if (num_bytes == 0) + return; + + /* + * Try to take num_bytes from the transaction's local delayed reserve. + * If not possible, try to take as much as it's available. If the local + * reserve doesn't have enough reserved space, the delayed refs reserve + * will be refilled next time btrfs_delayed_refs_rsv_refill() is called + * by someone or if a transaction commit is triggered before that, the + * global block reserve will be used. We want to minimize using the + * global block reserve for cases we can account for in advance, to + * avoid exhausting it and reach -ENOSPC during a transaction commit. + */ + spin_lock(&local_rsv->lock); + reserved_bytes = min(num_bytes, local_rsv->reserved); + local_rsv->reserved -= reserved_bytes; + local_rsv->full = (local_rsv->reserved >= local_rsv->size); + spin_unlock(&local_rsv->lock); + + spin_lock(&delayed_rsv->lock); + delayed_rsv->size += num_bytes; + delayed_rsv->reserved += reserved_bytes; + delayed_rsv->full = (delayed_rsv->reserved >= delayed_rsv->size); + spin_unlock(&delayed_rsv->lock); + trans->delayed_ref_updates = 0; + trans->delayed_ref_csum_deletions = 0; +} + +/* + * Adjust the size of the delayed refs block reserve for 1 block group item + * insertion, used after allocating a block group. + */ +void btrfs_inc_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv; + + spin_lock(&delayed_rsv->lock); + /* + * Inserting a block group item does not require changing the free space + * tree, only the extent tree or the block group tree, so this is all we + * need. + */ + delayed_rsv->size += btrfs_calc_insert_metadata_size(fs_info, 1); + delayed_rsv->full = false; + spin_unlock(&delayed_rsv->lock); +} + +/* + * Adjust the size of the delayed refs block reserve to release space for 1 + * block group item insertion. + */ +void btrfs_dec_delayed_refs_rsv_bg_inserts(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv; + const u64 num_bytes = btrfs_calc_insert_metadata_size(fs_info, 1); + u64 released; + + released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL); + if (released > 0) + trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", + 0, released, 0); +} + +/* + * Adjust the size of the delayed refs block reserve for 1 block group item + * update. + */ +void btrfs_inc_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv; + + spin_lock(&delayed_rsv->lock); + /* + * Updating a block group item does not result in new nodes/leaves and + * does not require changing the free space tree, only the extent tree + * or the block group tree, so this is all we need. + */ + delayed_rsv->size += btrfs_calc_metadata_size(fs_info, 1); + delayed_rsv->full = false; + spin_unlock(&delayed_rsv->lock); +} + +/* + * Adjust the size of the delayed refs block reserve to release space for 1 + * block group item update. + */ +void btrfs_dec_delayed_refs_rsv_bg_updates(struct btrfs_fs_info *fs_info) +{ + struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv; + const u64 num_bytes = btrfs_calc_metadata_size(fs_info, 1); + u64 released; + + released = btrfs_block_rsv_release(fs_info, delayed_rsv, num_bytes, NULL); + if (released > 0) + trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", + 0, released, 0); +} + +/* + * Refill based on our delayed refs usage. + * + * @fs_info: the filesystem + * @flush: control how we can flush for this reservation. + * + * This will refill the delayed block_rsv up to 1 items size worth of space and + * will return -ENOSPC if we can't make the reservation. + */ +static int btrfs_zoned_cap_metadata_reservation(struct btrfs_space_info *space_info) +{ + struct btrfs_fs_info *fs_info = space_info->fs_info; + struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv; + u64 usable; + u64 cap; + int ret = 0; + + if (!btrfs_is_zoned(fs_info)) + return 0; + + spin_lock(&space_info->lock); + usable = space_info->total_bytes - space_info->bytes_zone_unusable; + spin_unlock(&space_info->lock); + cap = usable >> 1; + + spin_lock(&block_rsv->lock); + if (block_rsv->size > cap) + ret = -EAGAIN; + spin_unlock(&block_rsv->lock); + + return ret; +} + +int btrfs_delayed_refs_rsv_refill(struct btrfs_fs_info *fs_info, + enum btrfs_reserve_flush_enum flush) +{ + struct btrfs_block_rsv *block_rsv = &fs_info->delayed_refs_rsv; + struct btrfs_space_info *space_info = block_rsv->space_info; + u64 limit = btrfs_calc_delayed_ref_bytes(fs_info, 1); + u64 num_bytes = 0; + u64 refilled_bytes; + u64 to_free; + int ret = -ENOSPC; + + spin_lock(&block_rsv->lock); + if (block_rsv->reserved < block_rsv->size) { + num_bytes = block_rsv->size - block_rsv->reserved; + num_bytes = min(num_bytes, limit); + } + spin_unlock(&block_rsv->lock); + + if (!num_bytes) + return 0; + + ret = btrfs_zoned_cap_metadata_reservation(space_info); + if (ret) + return ret; + + ret = btrfs_reserve_metadata_bytes(space_info, num_bytes, flush); + if (ret) + return ret; + + /* + * We may have raced with someone else, so check again if we the block + * reserve is still not full and release any excess space. + */ + spin_lock(&block_rsv->lock); + if (block_rsv->reserved < block_rsv->size) { + u64 needed = block_rsv->size - block_rsv->reserved; + + if (num_bytes >= needed) { + block_rsv->reserved += needed; + block_rsv->full = true; + to_free = num_bytes - needed; + refilled_bytes = needed; + } else { + block_rsv->reserved += num_bytes; + to_free = 0; + refilled_bytes = num_bytes; + } + } else { + to_free = num_bytes; + refilled_bytes = 0; + } + spin_unlock(&block_rsv->lock); + + if (to_free > 0) + btrfs_space_info_free_bytes_may_use(space_info, to_free); + + if (refilled_bytes > 0) + trace_btrfs_space_reservation(fs_info, "delayed_refs_rsv", 0, + refilled_bytes, 1); + return 0; +} + +/* + * compare two delayed data backrefs with same bytenr and type + */ +static int comp_data_refs(const struct btrfs_delayed_ref_node *ref1, + const struct btrfs_delayed_ref_node *ref2) +{ + if (ref1->data_ref.objectid < ref2->data_ref.objectid) + return -1; + if (ref1->data_ref.objectid > ref2->data_ref.objectid) + return 1; + if (ref1->data_ref.offset < ref2->data_ref.offset) + return -1; + if (ref1->data_ref.offset > ref2->data_ref.offset) + return 1; + return 0; +} + +static int comp_refs(const struct btrfs_delayed_ref_node *ref1, + const struct btrfs_delayed_ref_node *ref2, + bool check_seq) +{ + int ret = 0; + + if (ref1->type < ref2->type) + return -1; + if (ref1->type > ref2->type) + return 1; + if (ref1->type == BTRFS_SHARED_BLOCK_REF_KEY || + ref1->type == BTRFS_SHARED_DATA_REF_KEY) { + if (ref1->parent < ref2->parent) + return -1; + if (ref1->parent > ref2->parent) + return 1; + } else { + if (ref1->ref_root < ref2->ref_root) + return -1; + if (ref1->ref_root > ref2->ref_root) + return 1; + if (ref1->type == BTRFS_EXTENT_DATA_REF_KEY) + ret = comp_data_refs(ref1, ref2); + } + if (ret) + return ret; + if (check_seq) { + if (ref1->seq < ref2->seq) + return -1; + if (ref1->seq > ref2->seq) + return 1; + } + return 0; +} + +static int cmp_refs_node(const struct rb_node *new, const struct rb_node *exist) +{ + const struct btrfs_delayed_ref_node *new_node = + rb_entry(new, struct btrfs_delayed_ref_node, ref_node); + const struct btrfs_delayed_ref_node *exist_node = + rb_entry(exist, struct btrfs_delayed_ref_node, ref_node); + + return comp_refs(new_node, exist_node, true); +} + +static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root, + struct btrfs_delayed_ref_node *ins) +{ + struct rb_node *node = &ins->ref_node; + struct rb_node *exist = rb_find_add_cached(node, root, cmp_refs_node); + + return rb_entry_safe(exist, struct btrfs_delayed_ref_node, ref_node); +} + +static struct btrfs_delayed_ref_head *find_first_ref_head( + struct btrfs_delayed_ref_root *dr) +{ + unsigned long from = 0; + + lockdep_assert_held(&dr->lock); + + return xa_find(&dr->head_refs, &from, ULONG_MAX, XA_PRESENT); +} + +static bool btrfs_delayed_ref_lock(struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + lockdep_assert_held(&delayed_refs->lock); + if (mutex_trylock(&head->mutex)) + return true; + + refcount_inc(&head->refs); + spin_unlock(&delayed_refs->lock); + + mutex_lock(&head->mutex); + spin_lock(&delayed_refs->lock); + if (!head->tracked) { + mutex_unlock(&head->mutex); + btrfs_put_delayed_ref_head(head); + return false; + } + btrfs_put_delayed_ref_head(head); + return true; +} + +static inline void drop_delayed_ref(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head, + struct btrfs_delayed_ref_node *ref) +{ + lockdep_assert_held(&head->lock); + rb_erase_cached(&ref->ref_node, &head->ref_tree); + RB_CLEAR_NODE(&ref->ref_node); + if (!list_empty(&ref->add_list)) + list_del(&ref->add_list); + btrfs_put_delayed_ref(ref); + btrfs_delayed_refs_rsv_release(fs_info, 1, 0); +} + +static bool merge_ref(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head, + struct btrfs_delayed_ref_node *ref, + u64 seq) +{ + struct btrfs_delayed_ref_node *next; + struct rb_node *node = rb_next(&ref->ref_node); + bool done = false; + + while (!done && node) { + int mod; + + next = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + node = rb_next(node); + if (seq && next->seq >= seq) + break; + if (comp_refs(ref, next, false)) + break; + + if (ref->action == next->action) { + mod = next->ref_mod; + } else { + if (ref->ref_mod < next->ref_mod) { + swap(ref, next); + done = true; + } + mod = -next->ref_mod; + } + + drop_delayed_ref(fs_info, delayed_refs, head, next); + ref->ref_mod += mod; + if (ref->ref_mod == 0) { + drop_delayed_ref(fs_info, delayed_refs, head, ref); + done = true; + } else { + /* + * Can't have multiples of the same ref on a tree block. + */ + WARN_ON(ref->type == BTRFS_TREE_BLOCK_REF_KEY || + ref->type == BTRFS_SHARED_BLOCK_REF_KEY); + } + } + + return done; +} + +void btrfs_merge_delayed_refs(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_node *ref; + struct rb_node *node; + u64 seq = 0; + + lockdep_assert_held(&head->lock); + + if (RB_EMPTY_ROOT(&head->ref_tree.rb_root)) + return; + + /* We don't have too many refs to merge for data. */ + if (head->is_data) + return; + + seq = btrfs_tree_mod_log_lowest_seq(fs_info); +again: + for (node = rb_first_cached(&head->ref_tree); node; + node = rb_next(node)) { + ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + if (seq && ref->seq >= seq) + continue; + if (merge_ref(fs_info, delayed_refs, head, ref, seq)) + goto again; + } +} + +int btrfs_check_delayed_seq(struct btrfs_fs_info *fs_info, u64 seq) +{ + int ret = 0; + u64 min_seq = btrfs_tree_mod_log_lowest_seq(fs_info); + + if (min_seq != 0 && seq >= min_seq) { + btrfs_debug(fs_info, + "holding back delayed_ref %llu, lowest is %llu", + seq, min_seq); + ret = 1; + } + + return ret; +} + +struct btrfs_delayed_ref_head *btrfs_select_ref_head( + const struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs) +{ + struct btrfs_delayed_ref_head *head; + unsigned long start_index; + unsigned long found_index; + bool found_head = false; + bool locked; + + spin_lock(&delayed_refs->lock); +again: + start_index = (delayed_refs->run_delayed_start >> fs_info->sectorsize_bits); + xa_for_each_start(&delayed_refs->head_refs, found_index, head, start_index) { + if (!head->processing) { + found_head = true; + break; + } + } + if (!found_head) { + if (delayed_refs->run_delayed_start == 0) { + spin_unlock(&delayed_refs->lock); + return NULL; + } + delayed_refs->run_delayed_start = 0; + goto again; + } + + head->processing = true; + WARN_ON(delayed_refs->num_heads_ready == 0); + delayed_refs->num_heads_ready--; + delayed_refs->run_delayed_start = head->bytenr + + head->num_bytes; + + locked = btrfs_delayed_ref_lock(delayed_refs, head); + spin_unlock(&delayed_refs->lock); + + /* + * We may have dropped the spin lock to get the head mutex lock, and + * that might have given someone else time to free the head. If that's + * true, it has been removed from our list and we can move on. + */ + if (!locked) + return ERR_PTR(-EAGAIN); + + return head; +} + +void btrfs_unselect_ref_head(struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + spin_lock(&delayed_refs->lock); + head->processing = false; + delayed_refs->num_heads_ready++; + spin_unlock(&delayed_refs->lock); + btrfs_delayed_ref_unlock(head); +} + +void btrfs_delete_ref_head(const struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + struct btrfs_delayed_ref_head *head) +{ + const unsigned long index = (head->bytenr >> fs_info->sectorsize_bits); + + lockdep_assert_held(&delayed_refs->lock); + lockdep_assert_held(&head->lock); + + xa_erase(&delayed_refs->head_refs, index); + head->tracked = false; + delayed_refs->num_heads--; + if (!head->processing) + delayed_refs->num_heads_ready--; +} + +struct btrfs_delayed_ref_node *btrfs_select_delayed_ref(struct btrfs_delayed_ref_head *head) +{ + struct btrfs_delayed_ref_node *ref; + + lockdep_assert_held(&head->mutex); + lockdep_assert_held(&head->lock); + + if (RB_EMPTY_ROOT(&head->ref_tree.rb_root)) + return NULL; + + /* + * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first. + * This is to prevent a ref count from going down to zero, which deletes + * the extent item from the extent tree, when there still are references + * to add, which would fail because they would not find the extent item. + */ + if (!list_empty(&head->ref_add_list)) + return list_first_entry(&head->ref_add_list, + struct btrfs_delayed_ref_node, add_list); + + ref = rb_entry(rb_first_cached(&head->ref_tree), + struct btrfs_delayed_ref_node, ref_node); + ASSERT(list_empty(&ref->add_list)); + return ref; +} + +/* + * Helper to insert the ref_node to the tail or merge with tail. + * + * Return false if the ref was inserted. + * Return true if the ref was merged into an existing one (and therefore can be + * freed by the caller). + */ +static bool insert_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *href, + struct btrfs_delayed_ref_node *ref) +{ + struct btrfs_delayed_ref_root *root = &trans->transaction->delayed_refs; + struct btrfs_delayed_ref_node *exist; + int mod; + + ASSERT(ref->action == BTRFS_ADD_DELAYED_REF || + ref->action == BTRFS_DROP_DELAYED_REF); + + spin_lock(&href->lock); + exist = tree_insert(&href->ref_tree, ref); + if (!exist) { + if (ref->action == BTRFS_ADD_DELAYED_REF) + list_add_tail(&ref->add_list, &href->ref_add_list); + spin_unlock(&href->lock); + trans->delayed_ref_updates++; + return false; + } + + /* Now we are sure we can merge */ + if (exist->action == ref->action) { + mod = ref->ref_mod; + } else { + /* Need to change action */ + if (exist->ref_mod < ref->ref_mod) { + exist->action = ref->action; + mod = -exist->ref_mod; + exist->ref_mod = ref->ref_mod; + if (ref->action == BTRFS_ADD_DELAYED_REF) + list_add_tail(&exist->add_list, + &href->ref_add_list); + else if (ref->action == BTRFS_DROP_DELAYED_REF) { + ASSERT(!list_empty(&exist->add_list)); + list_del_init(&exist->add_list); + } else { + DEBUG_WARN(); + } + } else + mod = -ref->ref_mod; + } + exist->ref_mod += mod; + + /* remove existing tail if its ref_mod is zero */ + if (exist->ref_mod == 0) + drop_delayed_ref(trans->fs_info, root, href, exist); + spin_unlock(&href->lock); + return true; +} + +/* + * helper function to update the accounting in the head ref + * existing and update must have the same bytenr + */ +static noinline void update_existing_head_ref(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *existing, + struct btrfs_delayed_ref_head *update) +{ + struct btrfs_delayed_ref_root *delayed_refs = + &trans->transaction->delayed_refs; + struct btrfs_fs_info *fs_info = trans->fs_info; + int old_ref_mod; + + BUG_ON(existing->is_data != update->is_data); + + spin_lock(&existing->lock); + + /* + * When freeing an extent, we may not know the owning root when we + * first create the head_ref. However, some deref before the last deref + * will know it, so we just need to update the head_ref accordingly. + */ + if (!existing->owning_root) + existing->owning_root = update->owning_root; + + if (update->must_insert_reserved) { + /* if the extent was freed and then + * reallocated before the delayed ref + * entries were processed, we can end up + * with an existing head ref without + * the must_insert_reserved flag set. + * Set it again here + */ + existing->must_insert_reserved = update->must_insert_reserved; + existing->owning_root = update->owning_root; + + /* + * update the num_bytes so we make sure the accounting + * is done correctly + */ + existing->num_bytes = update->num_bytes; + + } + + if (update->extent_op) { + if (!existing->extent_op) { + existing->extent_op = update->extent_op; + } else { + if (update->extent_op->update_key) { + memcpy(&existing->extent_op->key, + &update->extent_op->key, + sizeof(update->extent_op->key)); + existing->extent_op->update_key = true; + } + if (update->extent_op->update_flags) { + existing->extent_op->flags_to_set |= + update->extent_op->flags_to_set; + existing->extent_op->update_flags = true; + } + btrfs_free_delayed_extent_op(update->extent_op); + } + } + /* + * update the reference mod on the head to reflect this new operation, + * only need the lock for this case cause we could be processing it + * currently, for refs we just added we know we're a-ok. + */ + old_ref_mod = existing->total_ref_mod; + existing->ref_mod += update->ref_mod; + existing->total_ref_mod += update->ref_mod; + + /* + * If we are going to from a positive ref mod to a negative or vice + * versa we need to make sure to adjust pending_csums accordingly. + * We reserve bytes for csum deletion when adding or updating a ref head + * see add_delayed_ref_head() for more details. + */ + if (existing->is_data) { + u64 csum_leaves = + btrfs_csum_bytes_to_leaves(fs_info, + existing->num_bytes); + + if (existing->total_ref_mod >= 0 && old_ref_mod < 0) { + delayed_refs->pending_csums -= existing->num_bytes; + btrfs_delayed_refs_rsv_release(fs_info, 0, csum_leaves); + } + if (existing->total_ref_mod < 0 && old_ref_mod >= 0) { + delayed_refs->pending_csums += existing->num_bytes; + trans->delayed_ref_csum_deletions += csum_leaves; + } + } + + spin_unlock(&existing->lock); +} + +static void init_delayed_ref_head(struct btrfs_delayed_ref_head *head_ref, + struct btrfs_ref *generic_ref, + struct btrfs_qgroup_extent_record *qrecord, + u64 reserved) +{ + int count_mod = 1; + bool must_insert_reserved = false; + + /* If reserved is provided, it must be a data extent. */ + BUG_ON(generic_ref->type != BTRFS_REF_DATA && reserved); + + switch (generic_ref->action) { + case BTRFS_ADD_DELAYED_REF: + /* count_mod is already set to 1. */ + break; + case BTRFS_UPDATE_DELAYED_HEAD: + count_mod = 0; + break; + case BTRFS_DROP_DELAYED_REF: + /* + * The head node stores the sum of all the mods, so dropping a ref + * should drop the sum in the head node by one. + */ + count_mod = -1; + break; + case BTRFS_ADD_DELAYED_EXTENT: + /* + * BTRFS_ADD_DELAYED_EXTENT means that we need to update the + * reserved accounting when the extent is finally added, or if a + * later modification deletes the delayed ref without ever + * inserting the extent into the extent allocation tree. + * ref->must_insert_reserved is the flag used to record that + * accounting mods are required. + * + * Once we record must_insert_reserved, switch the action to + * BTRFS_ADD_DELAYED_REF because other special casing is not + * required. + */ + must_insert_reserved = true; + break; + } + + refcount_set(&head_ref->refs, 1); + head_ref->bytenr = generic_ref->bytenr; + head_ref->num_bytes = generic_ref->num_bytes; + head_ref->ref_mod = count_mod; + head_ref->reserved_bytes = reserved; + head_ref->must_insert_reserved = must_insert_reserved; + head_ref->owning_root = generic_ref->owning_root; + head_ref->is_data = (generic_ref->type == BTRFS_REF_DATA); + head_ref->is_system = (generic_ref->ref_root == BTRFS_CHUNK_TREE_OBJECTID); + head_ref->ref_tree = RB_ROOT_CACHED; + INIT_LIST_HEAD(&head_ref->ref_add_list); + head_ref->tracked = false; + head_ref->processing = false; + head_ref->total_ref_mod = count_mod; + spin_lock_init(&head_ref->lock); + mutex_init(&head_ref->mutex); + + /* If not metadata set an impossible level to help debugging. */ + if (generic_ref->type == BTRFS_REF_METADATA) + head_ref->level = generic_ref->tree_ref.level; + else + head_ref->level = U8_MAX; + + if (qrecord) { + if (generic_ref->ref_root && reserved) { + qrecord->data_rsv = reserved; + qrecord->data_rsv_refroot = generic_ref->ref_root; + } + qrecord->num_bytes = generic_ref->num_bytes; + qrecord->old_roots = NULL; + } +} + +/* + * Helper function to actually insert a head node into the xarray. This does all + * the dirty work in terms of maintaining the correct overall modification + * count. + * + * The caller is responsible for calling kfree() on @qrecord. More specifically, + * if this function reports that it did not insert it as noted in + * @qrecord_inserted_ret, then it's safe to call kfree() on it. + * + * Returns an error pointer in case of an error. + */ +static noinline struct btrfs_delayed_ref_head * +add_delayed_ref_head(struct btrfs_trans_handle *trans, + struct btrfs_delayed_ref_head *head_ref, + struct btrfs_qgroup_extent_record *qrecord, + int action, bool *qrecord_inserted_ret) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_head *existing; + struct btrfs_delayed_ref_root *delayed_refs; + const unsigned long index = (head_ref->bytenr >> fs_info->sectorsize_bits); + + /* + * If 'qrecord_inserted_ret' is provided, then the first thing we need + * to do is to initialize it to false just in case we have an exit + * before trying to insert the record. + */ + if (qrecord_inserted_ret) + *qrecord_inserted_ret = false; + + delayed_refs = &trans->transaction->delayed_refs; + lockdep_assert_held(&delayed_refs->lock); + +#if BITS_PER_LONG == 32 + if (head_ref->bytenr >= MAX_LFS_FILESIZE) { + if (qrecord) + xa_release(&delayed_refs->dirty_extents, index); + btrfs_err_rl(fs_info, +"delayed ref head %llu is beyond 32bit page cache and xarray index limit", + head_ref->bytenr); + btrfs_err_32bit_limit(fs_info); + return ERR_PTR(-EOVERFLOW); + } +#endif + + /* Record qgroup extent info if provided */ + if (qrecord) { + /* + * Setting 'qrecord' but not 'qrecord_inserted_ret' will likely + * result in a memory leakage. + */ + ASSERT(qrecord_inserted_ret != NULL); + + int ret; + + ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, qrecord, + head_ref->bytenr); + if (ret) { + /* Clean up if insertion fails or item exists. */ + xa_release(&delayed_refs->dirty_extents, index); + if (ret < 0) + return ERR_PTR(ret); + } else if (qrecord_inserted_ret) { + *qrecord_inserted_ret = true; + } + } + + trace_add_delayed_ref_head(fs_info, head_ref, action); + + existing = xa_load(&delayed_refs->head_refs, index); + if (existing) { + update_existing_head_ref(trans, existing, head_ref); + /* + * we've updated the existing ref, free the newly + * allocated ref + */ + kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref); + head_ref = existing; + } else { + existing = xa_store(&delayed_refs->head_refs, index, head_ref, GFP_ATOMIC); + if (xa_is_err(existing)) { + /* Memory was preallocated by the caller. */ + ASSERT(xa_err(existing) != -ENOMEM); + return ERR_PTR(xa_err(existing)); + } else if (WARN_ON(existing)) { + /* + * Shouldn't happen we just did a lookup before under + * delayed_refs->lock. + */ + return ERR_PTR(-EEXIST); + } + head_ref->tracked = true; + /* + * We reserve the amount of bytes needed to delete csums when + * adding the ref head and not when adding individual drop refs + * since the csum items are deleted only after running the last + * delayed drop ref (the data extent's ref count drops to 0). + */ + if (head_ref->is_data && head_ref->ref_mod < 0) { + delayed_refs->pending_csums += head_ref->num_bytes; + trans->delayed_ref_csum_deletions += + btrfs_csum_bytes_to_leaves(fs_info, head_ref->num_bytes); + } + delayed_refs->num_heads++; + delayed_refs->num_heads_ready++; + } + + return head_ref; +} + +/* + * Initialize the structure which represents a modification to an extent. + * + * @fs_info: Internal to the mounted filesystem mount structure. + * + * @ref: The structure which is going to be initialized. + * + * @bytenr: The logical address of the extent for which a modification is + * going to be recorded. + * + * @num_bytes: Size of the extent whose modification is being recorded. + * + * @ref_root: The id of the root where this modification has originated, this + * can be either one of the well-known metadata trees or the + * subvolume id which references this extent. + * + * @action: Can be one of BTRFS_ADD_DELAYED_REF/BTRFS_DROP_DELAYED_REF or + * BTRFS_ADD_DELAYED_EXTENT + * + * @ref_type: Holds the type of the extent which is being recorded, can be + * one of BTRFS_SHARED_BLOCK_REF_KEY/BTRFS_TREE_BLOCK_REF_KEY + * when recording a metadata extent or BTRFS_SHARED_DATA_REF_KEY/ + * BTRFS_EXTENT_DATA_REF_KEY when recording data extent + */ +static void init_delayed_ref_common(struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_node *ref, + struct btrfs_ref *generic_ref) +{ + int action = generic_ref->action; + u64 seq = 0; + + if (action == BTRFS_ADD_DELAYED_EXTENT) + action = BTRFS_ADD_DELAYED_REF; + + if (btrfs_is_fstree(generic_ref->ref_root)) + seq = atomic64_read(&fs_info->tree_mod_seq); + + refcount_set(&ref->refs, 1); + ref->bytenr = generic_ref->bytenr; + ref->num_bytes = generic_ref->num_bytes; + ref->ref_mod = 1; + ref->action = action; + ref->seq = seq; + ref->type = btrfs_ref_type(generic_ref); + ref->ref_root = generic_ref->ref_root; + ref->parent = generic_ref->parent; + RB_CLEAR_NODE(&ref->ref_node); + INIT_LIST_HEAD(&ref->add_list); + + if (generic_ref->type == BTRFS_REF_DATA) + ref->data_ref = generic_ref->data_ref; + else + ref->tree_ref = generic_ref->tree_ref; +} + +void btrfs_init_tree_ref(struct btrfs_ref *generic_ref, int level, u64 mod_root, + bool skip_qgroup) +{ +#ifdef CONFIG_BTRFS_DEBUG + /* If @real_root not set, use @root as fallback */ + generic_ref->real_root = mod_root ?: generic_ref->ref_root; +#endif + generic_ref->tree_ref.level = level; + generic_ref->type = BTRFS_REF_METADATA; + if (skip_qgroup || !(btrfs_is_fstree(generic_ref->ref_root) && + (!mod_root || btrfs_is_fstree(mod_root)))) + generic_ref->skip_qgroup = true; + else + generic_ref->skip_qgroup = false; + +} + +void btrfs_init_data_ref(struct btrfs_ref *generic_ref, u64 ino, u64 offset, + u64 mod_root, bool skip_qgroup) +{ +#ifdef CONFIG_BTRFS_DEBUG + /* If @real_root not set, use @root as fallback */ + generic_ref->real_root = mod_root ?: generic_ref->ref_root; +#endif + generic_ref->data_ref.objectid = ino; + generic_ref->data_ref.offset = offset; + generic_ref->type = BTRFS_REF_DATA; + if (skip_qgroup || !(btrfs_is_fstree(generic_ref->ref_root) && + (!mod_root || btrfs_is_fstree(mod_root)))) + generic_ref->skip_qgroup = true; + else + generic_ref->skip_qgroup = false; +} + +static int add_delayed_ref(struct btrfs_trans_handle *trans, + struct btrfs_ref *generic_ref, + struct btrfs_delayed_extent_op *extent_op, + u64 reserved) +{ + struct btrfs_fs_info *fs_info = trans->fs_info; + struct btrfs_delayed_ref_node *node; + struct btrfs_delayed_ref_head *head_ref; + struct btrfs_delayed_ref_head *new_head_ref; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_qgroup_extent_record *record = NULL; + const unsigned long index = (generic_ref->bytenr >> fs_info->sectorsize_bits); + bool qrecord_reserved = false; + bool qrecord_inserted; + int action = generic_ref->action; + bool merged; + int ret; + + node = kmem_cache_alloc(btrfs_delayed_ref_node_cachep, GFP_NOFS); + if (!node) + return -ENOMEM; + + head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS); + if (!head_ref) { + ret = -ENOMEM; + goto free_node; + } + + delayed_refs = &trans->transaction->delayed_refs; + + if (btrfs_qgroup_full_accounting(fs_info) && !generic_ref->skip_qgroup) { + record = kzalloc_obj(*record, GFP_NOFS); + if (!record) { + ret = -ENOMEM; + goto free_head_ref; + } + if (xa_reserve(&delayed_refs->dirty_extents, index, GFP_NOFS)) { + ret = -ENOMEM; + goto free_record; + } + qrecord_reserved = true; + } + + ret = xa_reserve(&delayed_refs->head_refs, index, GFP_NOFS); + if (ret) { + if (qrecord_reserved) + xa_release(&delayed_refs->dirty_extents, index); + goto free_record; + } + + init_delayed_ref_common(fs_info, node, generic_ref); + init_delayed_ref_head(head_ref, generic_ref, record, reserved); + head_ref->extent_op = extent_op; + + spin_lock(&delayed_refs->lock); + + /* + * insert both the head node and the new ref without dropping + * the spin lock + */ + new_head_ref = add_delayed_ref_head(trans, head_ref, record, + action, &qrecord_inserted); + if (IS_ERR(new_head_ref)) { + xa_release(&delayed_refs->head_refs, index); + spin_unlock(&delayed_refs->lock); + ret = PTR_ERR(new_head_ref); + + /* + * It's only safe to call kfree() on 'qrecord' if + * add_delayed_ref_head() has _not_ inserted it for + * tracing. Otherwise we need to handle this here. + */ + if (!qrecord_reserved || qrecord_inserted) + goto free_head_ref; + goto free_record; + } + head_ref = new_head_ref; + + merged = insert_delayed_ref(trans, head_ref, node); + spin_unlock(&delayed_refs->lock); + + /* + * Need to update the delayed_refs_rsv with any changes we may have + * made. + */ + btrfs_update_delayed_refs_rsv(trans); + + if (generic_ref->type == BTRFS_REF_DATA) + trace_add_delayed_data_ref(trans->fs_info, node); + else + trace_add_delayed_tree_ref(trans->fs_info, node); + if (merged) + kmem_cache_free(btrfs_delayed_ref_node_cachep, node); + + if (qrecord_inserted) + return btrfs_qgroup_trace_extent_post(trans, record, generic_ref->bytenr); + + kfree(record); + return 0; + +free_record: + kfree(record); +free_head_ref: + kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref); +free_node: + kmem_cache_free(btrfs_delayed_ref_node_cachep, node); + return ret; +} + +/* + * Add a delayed tree ref. This does all of the accounting required to make sure + * the delayed ref is eventually processed before this transaction commits. + */ +int btrfs_add_delayed_tree_ref(struct btrfs_trans_handle *trans, + struct btrfs_ref *generic_ref, + struct btrfs_delayed_extent_op *extent_op) +{ + ASSERT(generic_ref->type == BTRFS_REF_METADATA && generic_ref->action); + return add_delayed_ref(trans, generic_ref, extent_op, 0); +} + +/* + * add a delayed data ref. it's similar to btrfs_add_delayed_tree_ref. + */ +int btrfs_add_delayed_data_ref(struct btrfs_trans_handle *trans, + struct btrfs_ref *generic_ref, + u64 reserved) +{ + ASSERT(generic_ref->type == BTRFS_REF_DATA && generic_ref->action); + return add_delayed_ref(trans, generic_ref, NULL, reserved); +} + +int btrfs_add_delayed_extent_op(struct btrfs_trans_handle *trans, + u64 bytenr, u64 num_bytes, u8 level, + struct btrfs_delayed_extent_op *extent_op) +{ + const unsigned long index = (bytenr >> trans->fs_info->sectorsize_bits); + struct btrfs_delayed_ref_head *head_ref; + struct btrfs_delayed_ref_head *head_ref_ret; + struct btrfs_delayed_ref_root *delayed_refs; + struct btrfs_ref generic_ref = { + .type = BTRFS_REF_METADATA, + .action = BTRFS_UPDATE_DELAYED_HEAD, + .bytenr = bytenr, + .num_bytes = num_bytes, + .tree_ref.level = level, + }; + int ret; + + head_ref = kmem_cache_alloc(btrfs_delayed_ref_head_cachep, GFP_NOFS); + if (!head_ref) + return -ENOMEM; + + init_delayed_ref_head(head_ref, &generic_ref, NULL, 0); + head_ref->extent_op = extent_op; + + delayed_refs = &trans->transaction->delayed_refs; + + ret = xa_reserve(&delayed_refs->head_refs, index, GFP_NOFS); + if (ret) { + kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref); + return ret; + } + + spin_lock(&delayed_refs->lock); + head_ref_ret = add_delayed_ref_head(trans, head_ref, NULL, + BTRFS_UPDATE_DELAYED_HEAD, NULL); + if (IS_ERR(head_ref_ret)) { + xa_release(&delayed_refs->head_refs, index); + spin_unlock(&delayed_refs->lock); + kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref); + return PTR_ERR(head_ref_ret); + } + spin_unlock(&delayed_refs->lock); + + /* + * Need to update the delayed_refs_rsv with any changes we may have + * made. + */ + btrfs_update_delayed_refs_rsv(trans); + return 0; +} + +void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref) +{ + if (refcount_dec_and_test(&ref->refs)) { + WARN_ON(!RB_EMPTY_NODE(&ref->ref_node)); + kmem_cache_free(btrfs_delayed_ref_node_cachep, ref); + } +} + +/* + * This does a simple search for the head node for a given extent. Returns the + * head node if found, or NULL if not. + */ +struct btrfs_delayed_ref_head * +btrfs_find_delayed_ref_head(const struct btrfs_fs_info *fs_info, + struct btrfs_delayed_ref_root *delayed_refs, + u64 bytenr) +{ + const unsigned long index = (bytenr >> fs_info->sectorsize_bits); + + lockdep_assert_held(&delayed_refs->lock); + + return xa_load(&delayed_refs->head_refs, index); +} + +static int find_comp(struct btrfs_delayed_ref_node *entry, u64 root, u64 parent) +{ + int type = parent ? BTRFS_SHARED_BLOCK_REF_KEY : BTRFS_TREE_BLOCK_REF_KEY; + + if (type < entry->type) + return -1; + if (type > entry->type) + return 1; + + if (type == BTRFS_TREE_BLOCK_REF_KEY) { + if (root < entry->ref_root) + return -1; + if (root > entry->ref_root) + return 1; + } else { + if (parent < entry->parent) + return -1; + if (parent > entry->parent) + return 1; + } + return 0; +} + +/* + * Check to see if a given root/parent reference is attached to the head. This + * only checks for BTRFS_ADD_DELAYED_REF references that match, as that + * indicates the reference exists for the given root or parent. This is for + * tree blocks only. + * + * @head: the head of the bytenr we're searching. + * @root: the root objectid of the reference if it is a normal reference. + * @parent: the parent if this is a shared backref. + */ +bool btrfs_find_delayed_tree_ref(struct btrfs_delayed_ref_head *head, + u64 root, u64 parent) +{ + struct rb_node *node; + bool found = false; + + lockdep_assert_held(&head->mutex); + + spin_lock(&head->lock); + node = head->ref_tree.rb_root.rb_node; + while (node) { + struct btrfs_delayed_ref_node *entry; + int ret; + + entry = rb_entry(node, struct btrfs_delayed_ref_node, ref_node); + ret = find_comp(entry, root, parent); + if (ret < 0) { + node = node->rb_left; + } else if (ret > 0) { + node = node->rb_right; + } else { + /* + * We only want to count ADD actions, as drops mean the + * ref doesn't exist. + */ + if (entry->action == BTRFS_ADD_DELAYED_REF) + found = true; + break; + } + } + spin_unlock(&head->lock); + return found; +} + +void btrfs_destroy_delayed_refs(struct btrfs_transaction *trans) +{ + struct btrfs_delayed_ref_root *delayed_refs = &trans->delayed_refs; + struct btrfs_fs_info *fs_info = trans->fs_info; + + spin_lock(&delayed_refs->lock); + while (true) { + struct btrfs_delayed_ref_head *head; + struct rb_node *n; + bool pin_bytes = false; + + head = find_first_ref_head(delayed_refs); + if (!head) + break; + + if (!btrfs_delayed_ref_lock(delayed_refs, head)) + continue; + + spin_lock(&head->lock); + while ((n = rb_first_cached(&head->ref_tree)) != NULL) { + struct btrfs_delayed_ref_node *ref; + + ref = rb_entry(n, struct btrfs_delayed_ref_node, ref_node); + drop_delayed_ref(fs_info, delayed_refs, head, ref); + } + if (head->must_insert_reserved) + pin_bytes = true; + btrfs_free_delayed_extent_op(head->extent_op); + btrfs_delete_ref_head(fs_info, delayed_refs, head); + spin_unlock(&head->lock); + spin_unlock(&delayed_refs->lock); + mutex_unlock(&head->mutex); + + if (!btrfs_is_testing(fs_info) && pin_bytes) { + struct btrfs_block_group *bg; + + bg = btrfs_lookup_block_group(fs_info, head->bytenr); + if (WARN_ON_ONCE(bg == NULL)) { + /* + * Unexpected and there's nothing we can do here + * because we are in a transaction abort path, + * so any errors can only be ignored or reported + * while attempting to cleanup all resources. + */ + btrfs_err(fs_info, +"block group for delayed ref at %llu was not found while destroying ref head", + head->bytenr); + } else { + spin_lock(&bg->space_info->lock); + spin_lock(&bg->lock); + bg->pinned += head->num_bytes; + btrfs_space_info_update_bytes_pinned(bg->space_info, + head->num_bytes); + bg->reserved -= head->num_bytes; + bg->space_info->bytes_reserved -= head->num_bytes; + spin_unlock(&bg->lock); + spin_unlock(&bg->space_info->lock); + + btrfs_put_block_group(bg); + } + + btrfs_error_unpin_extent_range(fs_info, head->bytenr, + head->bytenr + head->num_bytes - 1); + } + if (!btrfs_is_testing(fs_info)) + btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head); + btrfs_put_delayed_ref_head(head); + cond_resched(); + spin_lock(&delayed_refs->lock); + } + + if (!btrfs_is_testing(fs_info)) + btrfs_qgroup_destroy_extent_records(trans); + + spin_unlock(&delayed_refs->lock); +} + +void __cold btrfs_delayed_ref_exit(void) +{ + kmem_cache_destroy(btrfs_delayed_ref_head_cachep); + kmem_cache_destroy(btrfs_delayed_ref_node_cachep); + kmem_cache_destroy(btrfs_delayed_extent_op_cachep); +} + +int __init btrfs_delayed_ref_init(void) +{ + btrfs_delayed_ref_head_cachep = KMEM_CACHE(btrfs_delayed_ref_head, 0); + if (!btrfs_delayed_ref_head_cachep) + return -ENOMEM; + + btrfs_delayed_ref_node_cachep = KMEM_CACHE(btrfs_delayed_ref_node, 0); + if (!btrfs_delayed_ref_node_cachep) + goto fail; + + btrfs_delayed_extent_op_cachep = KMEM_CACHE(btrfs_delayed_extent_op, 0); + if (!btrfs_delayed_extent_op_cachep) + goto fail; + + return 0; +fail: + btrfs_delayed_ref_exit(); + return -ENOMEM; +} |