// 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 "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;
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.
*/
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_reserve_metadata_bytes(fs_info, 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(fs_info, 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(struct btrfs_delayed_ref_node *ref1,
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(struct btrfs_delayed_ref_node *ref1,
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;
}
/* insert a new ref to head ref rbtree */
static struct btrfs_delayed_ref_head *htree_insert(struct rb_root_cached *root,
struct rb_node *node)
{
struct rb_node **p = &root->rb_root.rb_node;
struct rb_node *parent_node = NULL;
struct btrfs_delayed_ref_head *entry;
struct btrfs_delayed_ref_head *ins;
u64 bytenr;
bool leftmost = true;
ins = rb_entry(node, struct btrfs_delayed_ref_head, href_node);
bytenr = ins->bytenr;
while (*p) {
parent_node = *p;
entry = rb_entry(parent_node, struct btrfs_delayed_ref_head,
href_node);
if (bytenr < entry->bytenr) {
p = &(*p)->rb_left;
} else if (bytenr > entry->bytenr) {
p = &(*p)->rb_right;
leftmost = false;
} else {
return entry;
}
}
rb_link_node(node, parent_node, p);
rb_insert_color_cached(node, root, leftmost);
return NULL;
}
static struct btrfs_delayed_ref_node* tree_insert(struct rb_root_cached *root,
struct btrfs_delayed_ref_node *ins)
{
struct rb_node **p = &root->rb_root.rb_node;
struct rb_node *node = &ins->ref_node;
struct rb_node *parent_node = NULL;
struct btrfs_delayed_ref_node *entry;
bool leftmost = true;
while (*p) {
int comp;
parent_node = *p;
entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
ref_node);
comp = comp_refs(ins, entry, true);
if (comp < 0) {
p = &(*p)->rb_left;
} else if (comp > 0) {
p = &(*p)->rb_right;
leftmost = false;
} else {
return entry;
}
}
rb_link_node(node, parent_node, p);
rb_insert_color_cached(node, root, leftmost);
return NULL;
}
static struct btrfs_delayed_ref_head *find_first_ref_head(
struct btrfs_delayed_ref_root *dr)
{
struct rb_node *n;
struct btrfs_delayed_ref_head *entry;
n = rb_first_cached(&dr->href_root);
if (!n)
return NULL;
entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
return entry;
}
/*
* Find a head entry based on bytenr. This returns the delayed ref head if it
* was able to find one, or NULL if nothing was in that spot. If return_bigger
* is given, the next bigger entry is returned if no exact match is found.
*/
static struct btrfs_delayed_ref_head *find_ref_head(
struct btrfs_delayed_ref_root *dr, u64 bytenr,
bool return_bigger)
{
struct rb_root *root = &dr->href_root.rb_root;
struct rb_node *n;
struct btrfs_delayed_ref_head *entry;
n = root->rb_node;
entry = NULL;
while (n) {
entry = rb_entry(n, struct btrfs_delayed_ref_head, href_node);
if (bytenr < entry->bytenr)
n = n->rb_left;
else if (bytenr > entry->bytenr)
n = n->rb_right;
else
return entry;
}
if (entry && return_bigger) {
if (bytenr > entry->bytenr) {
n = rb_next(&entry->href_node);
if (!n)
return NULL;
entry = rb_entry(n, struct btrfs_delayed_ref_head,
href_node);
}
return entry;
}
return NULL;
}
int 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 0;
refcount_inc(&head->refs);
spin_unlock(&delayed_refs->lock);
mutex_lock(&head->mutex);
spin_lock(&delayed_refs->lock);
if (RB_EMPTY_NODE(&head->href_node)) {
mutex_unlock(&head->mutex);
btrfs_put_delayed_ref_head(head);
return -EAGAIN;
}
btrfs_put_delayed_ref_head(head);
return 0;
}
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);
atomic_dec(&delayed_refs->num_entries);
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(
struct btrfs_delayed_ref_root *delayed_refs)
{
struct btrfs_delayed_ref_head *head;
lockdep_assert_held(&delayed_refs->lock);
again:
head = find_ref_head(delayed_refs, delayed_refs->run_delayed_start,
true);
if (!head && delayed_refs->run_delayed_start != 0) {
delayed_refs->run_delayed_start = 0;
head = find_first_ref_head(delayed_refs);
}
if (!head)
return NULL;
while (head->processing) {
struct rb_node *node;
node = rb_next(&head->href_node);
if (!node) {
if (delayed_refs->run_delayed_start == 0)
return NULL;
delayed_refs->run_delayed_start = 0;
goto again;
}
head = rb_entry(node, struct btrfs_delayed_ref_head,
href_node);
}
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;
return head;
}
void btrfs_delete_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
struct btrfs_delayed_ref_head *head)
{
lockdep_assert_held(&delayed_refs->lock);
lockdep_assert_held(&head->lock);
rb_erase_cached(&head->href_node, &delayed_refs->href_root);
RB_CLEAR_NODE(&head->href_node);
atomic_dec(&delayed_refs->num_entries);
delayed_refs->num_heads--;
if (!head->processing)
delayed_refs->num_heads_ready--;
}
/*
* 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;
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);
atomic_inc(&root->num_entries);
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(&exist->add_list);
} else {
ASSERT(0);
}
} 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);
RB_CLEAR_NODE(&head_ref->href_node);
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->bytenr = generic_ref->bytenr;
qrecord->num_bytes = generic_ref->num_bytes;
qrecord->old_roots = NULL;
}
}
/*
* helper function to actually insert a head node into the rbtree.
* this does all the dirty work in terms of maintaining the correct
* overall modification count.
*/
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_delayed_ref_head *existing;
struct btrfs_delayed_ref_root *delayed_refs;
bool qrecord_inserted = false;
delayed_refs = &trans->transaction->delayed_refs;
/* Record qgroup extent info if provided */
if (qrecord) {
int ret;
ret = btrfs_qgroup_trace_extent_nolock(trans->fs_info,
delayed_refs, qrecord);
if (ret) {
/* Clean up if insertion fails or item exists. */
xa_release(&delayed_refs->dirty_extents, qrecord->bytenr);
kfree(qrecord);
} else {
qrecord_inserted = true;
}
}
trace_add_delayed_ref_head(trans->fs_info, head_ref, action);
existing = htree_insert(&delayed_refs->href_root,
&head_ref->href_node);
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 {
/*
* 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(trans->fs_info,
head_ref->num_bytes);
}
delayed_refs->num_heads++;
delayed_refs->num_heads_ready++;
atomic_inc(&delayed_refs->num_entries);
}
if (qrecord_inserted_ret)
*qrecord_inserted_ret = qrecord_inserted;
return head_ref;
}
/*
* Initialize the structure which represents a modification to a 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 (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_FS_REF_VERIFY
/* 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 || !(is_fstree(generic_ref->ref_root) &&
(!mod_root || 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_FS_REF_VERIFY
/* 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 || !(is_fstree(generic_ref->ref_root) &&
(!mod_root || 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_root *delayed_refs;
struct btrfs_qgroup_extent_record *record = NULL;
bool qrecord_inserted;
int action = generic_ref->action;
bool merged;
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)
goto free_node;
if (btrfs_qgroup_full_accounting(fs_info) && !generic_ref->skip_qgroup) {
record = kzalloc(sizeof(*record), GFP_NOFS);
if (!record)
goto free_head_ref;
if (xa_reserve(&trans->transaction->delayed_refs.dirty_extents,
generic_ref->bytenr, GFP_NOFS))
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;
delayed_refs = &trans->transaction->delayed_refs;
spin_lock(&delayed_refs->lock);
/*
* insert both the head node and the new ref without dropping
* the spin lock
*/
head_ref = add_delayed_ref_head(trans, head_ref, record,
action, &qrecord_inserted);
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);
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 -ENOMEM;
}
/*
* 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)
{
struct btrfs_delayed_ref_head *head_ref;
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,
};
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;
spin_lock(&delayed_refs->lock);
add_delayed_ref_head(trans, head_ref, NULL, BTRFS_UPDATE_DELAYED_HEAD,
NULL);
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(struct btrfs_delayed_ref_root *delayed_refs, u64 bytenr)
{
lockdep_assert_held(&delayed_refs->lock);
return find_ref_head(delayed_refs, bytenr, false);
}
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 __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)
goto fail;
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;
}
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