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linux/fs/btrfs/transaction.c
Christoph Hellwig f880fe6e0b btrfs: don't hold an extra reference for redirtied buffers 
When btrfs_redirty_list_add redirties a buffer, it also acquires
an extra reference that is released on transaction commit.  But
this is not required as buffers that are dirty or under writeback
are never freed (look for calls to extent_buffer_under_io())).

Remove the extra reference and the infrastructure used to drop it
again.

History behind redirty logic:

In the first place, it used releasing_list to hold all the
to-be-released extent buffers, and decided which buffers to re-dirty at
the commit time. Then, in a later version, the behaviour got changed to
re-dirty a necessary buffer and add re-dirtied one to the list in
btrfs_free_tree_block(). In short, the list was there mostly for the
patch series' historical reason.

Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[ add Naohiro's comment regarding history ]
Signed-off-by: David Sterba <dsterba@suse.com>
2023-06-19 13:59:26 +02:00

2651 lines
78 KiB
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007 Oracle. All rights reserved.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/writeback.h>
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/uuid.h>
#include <linux/timekeeping.h>
#include "misc.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "locking.h"
#include "tree-log.h"
#include "volumes.h"
#include "dev-replace.h"
#include "qgroup.h"
#include "block-group.h"
#include "space-info.h"
#include "zoned.h"
#include "fs.h"
#include "accessors.h"
#include "extent-tree.h"
#include "root-tree.h"
#include "defrag.h"
#include "dir-item.h"
#include "uuid-tree.h"
#include "ioctl.h"
#include "relocation.h"
#include "scrub.h"
static struct kmem_cache *btrfs_trans_handle_cachep;
#define BTRFS_ROOT_TRANS_TAG 0
/*
* Transaction states and transitions
*
* No running transaction (fs tree blocks are not modified)
* |
* | To next stage:
* | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
* V
* Transaction N [[TRANS_STATE_RUNNING]]
* |
* | New trans handles can be attached to transaction N by calling all
* | start_transaction() variants.
* |
* | To next stage:
* | Call btrfs_commit_transaction() on any trans handle attached to
* | transaction N
* V
* Transaction N [[TRANS_STATE_COMMIT_START]]
* |
* | Will wait for previous running transaction to completely finish if there
* | is one
* |
* | Then one of the following happes:
* | - Wait for all other trans handle holders to release.
* | The btrfs_commit_transaction() caller will do the commit work.
* | - Wait for current transaction to be committed by others.
* | Other btrfs_commit_transaction() caller will do the commit work.
* |
* | At this stage, only btrfs_join_transaction*() variants can attach
* | to this running transaction.
* | All other variants will wait for current one to finish and attach to
* | transaction N+1.
* |
* | To next stage:
* | Caller is chosen to commit transaction N, and all other trans handle
* | haven been released.
* V
* Transaction N [[TRANS_STATE_COMMIT_DOING]]
* |
* | The heavy lifting transaction work is started.
* | From running delayed refs (modifying extent tree) to creating pending
* | snapshots, running qgroups.
* | In short, modify supporting trees to reflect modifications of subvolume
* | trees.
* |
* | At this stage, all start_transaction() calls will wait for this
* | transaction to finish and attach to transaction N+1.
* |
* | To next stage:
* | Until all supporting trees are updated.
* V
* Transaction N [[TRANS_STATE_UNBLOCKED]]
* | Transaction N+1
* | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
* | need to write them back to disk and update |
* | super blocks. |
* | |
* | At this stage, new transaction is allowed to |
* | start. |
* | All new start_transaction() calls will be |
* | attached to transid N+1. |
* | |
* | To next stage: |
* | Until all tree blocks are super blocks are |
* | written to block devices |
* V |
* Transaction N [[TRANS_STATE_COMPLETED]] V
* All tree blocks and super blocks are written. Transaction N+1
* This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
* data structures will be cleaned up. | Life goes on
*/
static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
[TRANS_STATE_RUNNING] = 0U,
[TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
[TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOSTART),
[TRANS_STATE_UNBLOCKED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOLOCK |
__TRANS_JOIN_NOSTART),
[TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOLOCK |
__TRANS_JOIN_NOSTART),
[TRANS_STATE_COMPLETED] = (__TRANS_START |
__TRANS_ATTACH |
__TRANS_JOIN |
__TRANS_JOIN_NOLOCK |
__TRANS_JOIN_NOSTART),
};
void btrfs_put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(refcount_read(&transaction->use_count) == 0);
if (refcount_dec_and_test(&transaction->use_count)) {
BUG_ON(!list_empty(&transaction->list));
WARN_ON(!RB_EMPTY_ROOT(
&transaction->delayed_refs.href_root.rb_root));
WARN_ON(!RB_EMPTY_ROOT(
&transaction->delayed_refs.dirty_extent_root));
if (transaction->delayed_refs.pending_csums)
btrfs_err(transaction->fs_info,
"pending csums is %llu",
transaction->delayed_refs.pending_csums);
/*
* If any block groups are found in ->deleted_bgs then it's
* because the transaction was aborted and a commit did not
* happen (things failed before writing the new superblock
* and calling btrfs_finish_extent_commit()), so we can not
* discard the physical locations of the block groups.
*/
while (!list_empty(&transaction->deleted_bgs)) {
struct btrfs_block_group *cache;
cache = list_first_entry(&transaction->deleted_bgs,
struct btrfs_block_group,
bg_list);
list_del_init(&cache->bg_list);
btrfs_unfreeze_block_group(cache);
btrfs_put_block_group(cache);
}
WARN_ON(!list_empty(&transaction->dev_update_list));
kfree(transaction);
}
}
static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
{
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *root, *tmp;
/*
* At this point no one can be using this transaction to modify any tree
* and no one can start another transaction to modify any tree either.
*/
ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
down_write(&fs_info->commit_root_sem);
if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
fs_info->last_reloc_trans = trans->transid;
list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
dirty_list) {
list_del_init(&root->dirty_list);
free_extent_buffer(root->commit_root);
root->commit_root = btrfs_root_node(root);
extent_io_tree_release(&root->dirty_log_pages);
btrfs_qgroup_clean_swapped_blocks(root);
}
/* We can free old roots now. */
spin_lock(&cur_trans->dropped_roots_lock);
while (!list_empty(&cur_trans->dropped_roots)) {
root = list_first_entry(&cur_trans->dropped_roots,
struct btrfs_root, root_list);
list_del_init(&root->root_list);
spin_unlock(&cur_trans->dropped_roots_lock);
btrfs_free_log(trans, root);
btrfs_drop_and_free_fs_root(fs_info, root);
spin_lock(&cur_trans->dropped_roots_lock);
}
spin_unlock(&cur_trans->dropped_roots_lock);
up_write(&fs_info->commit_root_sem);
}
static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
unsigned int type)
{
if (type & TRANS_EXTWRITERS)
atomic_inc(&trans->num_extwriters);
}
static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
unsigned int type)
{
if (type & TRANS_EXTWRITERS)
atomic_dec(&trans->num_extwriters);
}
static inline void extwriter_counter_init(struct btrfs_transaction *trans,
unsigned int type)
{
atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
}
static inline int extwriter_counter_read(struct btrfs_transaction *trans)
{
return atomic_read(&trans->num_extwriters);
}
/*
* To be called after doing the chunk btree updates right after allocating a new
* chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
* chunk after all chunk btree updates and after finishing the second phase of
* chunk allocation (btrfs_create_pending_block_groups()) in case some block
* group had its chunk item insertion delayed to the second phase.
*/
void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
if (!trans->chunk_bytes_reserved)
return;
btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
trans->chunk_bytes_reserved, NULL);
trans->chunk_bytes_reserved = 0;
}
/*
* either allocate a new transaction or hop into the existing one
*/
static noinline int join_transaction(struct btrfs_fs_info *fs_info,
unsigned int type)
{
struct btrfs_transaction *cur_trans;
spin_lock(&fs_info->trans_lock);
loop:
/* The file system has been taken offline. No new transactions. */
if (BTRFS_FS_ERROR(fs_info)) {
spin_unlock(&fs_info->trans_lock);
return -EROFS;
}
cur_trans = fs_info->running_transaction;
if (cur_trans) {
if (TRANS_ABORTED(cur_trans)) {
spin_unlock(&fs_info->trans_lock);
return cur_trans->aborted;
}
if (btrfs_blocked_trans_types[cur_trans->state] & type) {
spin_unlock(&fs_info->trans_lock);
return -EBUSY;
}
refcount_inc(&cur_trans->use_count);
atomic_inc(&cur_trans->num_writers);
extwriter_counter_inc(cur_trans, type);
spin_unlock(&fs_info->trans_lock);
btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
return 0;
}
spin_unlock(&fs_info->trans_lock);
/*
* If we are ATTACH, we just want to catch the current transaction,
* and commit it. If there is no transaction, just return ENOENT.
*/
if (type == TRANS_ATTACH)
return -ENOENT;
/*
* JOIN_NOLOCK only happens during the transaction commit, so
* it is impossible that ->running_transaction is NULL
*/
BUG_ON(type == TRANS_JOIN_NOLOCK);
cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
if (!cur_trans)
return -ENOMEM;
btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
spin_lock(&fs_info->trans_lock);
if (fs_info->running_transaction) {
/*
* someone started a transaction after we unlocked. Make sure
* to redo the checks above
*/
btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
kfree(cur_trans);
goto loop;
} else if (BTRFS_FS_ERROR(fs_info)) {
spin_unlock(&fs_info->trans_lock);
btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
kfree(cur_trans);
return -EROFS;
}
cur_trans->fs_info = fs_info;
atomic_set(&cur_trans->pending_ordered, 0);
init_waitqueue_head(&cur_trans->pending_wait);
atomic_set(&cur_trans->num_writers, 1);
extwriter_counter_init(cur_trans, type);
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->state = TRANS_STATE_RUNNING;
/*
* One for this trans handle, one so it will live on until we
* commit the transaction.
*/
refcount_set(&cur_trans->use_count, 2);
cur_trans->flags = 0;
cur_trans->start_time = ktime_get_seconds();
memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
atomic_set(&cur_trans->delayed_refs.num_entries, 0);
/*
* although the tree mod log is per file system and not per transaction,
* the log must never go across transaction boundaries.
*/
smp_mb();
if (!list_empty(&fs_info->tree_mod_seq_list))
WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
atomic64_set(&fs_info->tree_mod_seq, 0);
spin_lock_init(&cur_trans->delayed_refs.lock);
INIT_LIST_HEAD(&cur_trans->pending_snapshots);
INIT_LIST_HEAD(&cur_trans->dev_update_list);
INIT_LIST_HEAD(&cur_trans->switch_commits);
INIT_LIST_HEAD(&cur_trans->dirty_bgs);
INIT_LIST_HEAD(&cur_trans->io_bgs);
INIT_LIST_HEAD(&cur_trans->dropped_roots);
mutex_init(&cur_trans->cache_write_mutex);
spin_lock_init(&cur_trans->dirty_bgs_lock);
INIT_LIST_HEAD(&cur_trans->deleted_bgs);
spin_lock_init(&cur_trans->dropped_roots_lock);
list_add_tail(&cur_trans->list, &fs_info->trans_list);
extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
IO_TREE_TRANS_DIRTY_PAGES);
extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
IO_TREE_FS_PINNED_EXTENTS);
fs_info->generation++;
cur_trans->transid = fs_info->generation;
fs_info->running_transaction = cur_trans;
cur_trans->aborted = 0;
spin_unlock(&fs_info->trans_lock);
return 0;
}
/*
* This does all the record keeping required to make sure that a shareable root
* is properly recorded in a given transaction. This is required to make sure
* the old root from before we joined the transaction is deleted when the
* transaction commits.
*/
static int record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int force)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret = 0;
if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
root->last_trans < trans->transid) || force) {
WARN_ON(!force && root->commit_root != root->node);
/*
* see below for IN_TRANS_SETUP usage rules
* we have the reloc mutex held now, so there
* is only one writer in this function
*/
set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
/* make sure readers find IN_TRANS_SETUP before
* they find our root->last_trans update
*/
smp_wmb();
spin_lock(&fs_info->fs_roots_radix_lock);
if (root->last_trans == trans->transid && !force) {
spin_unlock(&fs_info->fs_roots_radix_lock);
return 0;
}
radix_tree_tag_set(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
root->last_trans = trans->transid;
/* this is pretty tricky. We don't want to
* take the relocation lock in btrfs_record_root_in_trans
* unless we're really doing the first setup for this root in
* this transaction.
*
* Normally we'd use root->last_trans as a flag to decide
* if we want to take the expensive mutex.
*
* But, we have to set root->last_trans before we
* init the relocation root, otherwise, we trip over warnings
* in ctree.c. The solution used here is to flag ourselves
* with root IN_TRANS_SETUP. When this is 1, we're still
* fixing up the reloc trees and everyone must wait.
*
* When this is zero, they can trust root->last_trans and fly
* through btrfs_record_root_in_trans without having to take the
* lock. smp_wmb() makes sure that all the writes above are
* done before we pop in the zero below
*/
ret = btrfs_init_reloc_root(trans, root);
smp_mb__before_atomic();
clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
}
return ret;
}
void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
/* Add ourselves to the transaction dropped list */
spin_lock(&cur_trans->dropped_roots_lock);
list_add_tail(&root->root_list, &cur_trans->dropped_roots);
spin_unlock(&cur_trans->dropped_roots_lock);
/* Make sure we don't try to update the root at commit time */
spin_lock(&fs_info->fs_roots_radix_lock);
radix_tree_tag_clear(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
}
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;
if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
return 0;
/*
* see record_root_in_trans for comments about IN_TRANS_SETUP usage
* and barriers
*/
smp_rmb();
if (root->last_trans == trans->transid &&
!test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
return 0;
mutex_lock(&fs_info->reloc_mutex);
ret = record_root_in_trans(trans, root, 0);
mutex_unlock(&fs_info->reloc_mutex);
return ret;
}
static inline int is_transaction_blocked(struct btrfs_transaction *trans)
{
return (trans->state >= TRANS_STATE_COMMIT_START &&
trans->state < TRANS_STATE_UNBLOCKED &&
!TRANS_ABORTED(trans));
}
/* wait for commit against the current transaction to become unblocked
* when this is done, it is safe to start a new transaction, but the current
* transaction might not be fully on disk.
*/
static void wait_current_trans(struct btrfs_fs_info *fs_info)
{
struct btrfs_transaction *cur_trans;
spin_lock(&fs_info->trans_lock);
cur_trans = fs_info->running_transaction;
if (cur_trans && is_transaction_blocked(cur_trans)) {
refcount_inc(&cur_trans->use_count);
spin_unlock(&fs_info->trans_lock);
btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
wait_event(fs_info->transaction_wait,
cur_trans->state >= TRANS_STATE_UNBLOCKED ||
TRANS_ABORTED(cur_trans));
btrfs_put_transaction(cur_trans);
} else {
spin_unlock(&fs_info->trans_lock);
}
}
static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
{
if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
return 0;
if (type == TRANS_START)
return 1;
return 0;
}
static inline bool need_reserve_reloc_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
if (!fs_info->reloc_ctl ||
!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
root->reloc_root)
return false;
return true;
}
static struct btrfs_trans_handle *
start_transaction(struct btrfs_root *root, unsigned int num_items,
unsigned int type, enum btrfs_reserve_flush_enum flush,
bool enforce_qgroups)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
struct btrfs_trans_handle *h;
struct btrfs_transaction *cur_trans;
u64 num_bytes = 0;
u64 qgroup_reserved = 0;
bool reloc_reserved = false;
bool do_chunk_alloc = false;
int ret;
if (BTRFS_FS_ERROR(fs_info))
return ERR_PTR(-EROFS);
if (current->journal_info) {
WARN_ON(type & TRANS_EXTWRITERS);
h = current->journal_info;
refcount_inc(&h->use_count);
WARN_ON(refcount_read(&h->use_count) > 2);
h->orig_rsv = h->block_rsv;
h->block_rsv = NULL;
goto got_it;
}
/*
* Do the reservation before we join the transaction so we can do all
* the appropriate flushing if need be.
*/
if (num_items && root != fs_info->chunk_root) {
struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
u64 delayed_refs_bytes = 0;
qgroup_reserved = num_items * fs_info->nodesize;
ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
enforce_qgroups);
if (ret)
return ERR_PTR(ret);
/*
* We want to reserve all the bytes we may need all at once, so
* we only do 1 enospc flushing cycle per transaction start. We
* accomplish this by simply assuming we'll do num_items worth
* of delayed refs updates in this trans handle, and refill that
* amount for whatever is missing in the reserve.
*/
num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
if (flush == BTRFS_RESERVE_FLUSH_ALL &&
!btrfs_block_rsv_full(delayed_refs_rsv)) {
delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info,
num_items);
num_bytes += delayed_refs_bytes;
}
/*
* Do the reservation for the relocation root creation
*/
if (need_reserve_reloc_root(root)) {
num_bytes += fs_info->nodesize;
reloc_reserved = true;
}
ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes, flush);
if (ret)
goto reserve_fail;
if (delayed_refs_bytes) {
btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
delayed_refs_bytes);
num_bytes -= delayed_refs_bytes;
}
if (rsv->space_info->force_alloc)
do_chunk_alloc = true;
} else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
!btrfs_block_rsv_full(delayed_refs_rsv)) {
/*
* Some people call with btrfs_start_transaction(root, 0)
* because they can be throttled, but have some other mechanism
* for reserving space. We still want these guys to refill the
* delayed block_rsv so just add 1 items worth of reservation
* here.
*/
ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
if (ret)
goto reserve_fail;
}
again:
h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
if (!h) {
ret = -ENOMEM;
goto alloc_fail;
}
/*
* If we are JOIN_NOLOCK we're already committing a transaction and
* waiting on this guy, so we don't need to do the sb_start_intwrite
* because we're already holding a ref. We need this because we could
* have raced in and did an fsync() on a file which can kick a commit
* and then we deadlock with somebody doing a freeze.
*
* If we are ATTACH, it means we just want to catch the current
* transaction and commit it, so we needn't do sb_start_intwrite().
*/
if (type & __TRANS_FREEZABLE)
sb_start_intwrite(fs_info->sb);
if (may_wait_transaction(fs_info, type))
wait_current_trans(fs_info);
do {
ret = join_transaction(fs_info, type);
if (ret == -EBUSY) {
wait_current_trans(fs_info);
if (unlikely(type == TRANS_ATTACH ||
type == TRANS_JOIN_NOSTART))
ret = -ENOENT;
}
} while (ret == -EBUSY);
if (ret < 0)
goto join_fail;
cur_trans = fs_info->running_transaction;
h->transid = cur_trans->transid;
h->transaction = cur_trans;
refcount_set(&h->use_count, 1);
h->fs_info = root->fs_info;
h->type = type;
INIT_LIST_HEAD(&h->new_bgs);
smp_mb();
if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
may_wait_transaction(fs_info, type)) {
current->journal_info = h;
btrfs_commit_transaction(h);
goto again;
}
if (num_bytes) {
trace_btrfs_space_reservation(fs_info, "transaction",
h->transid, num_bytes, 1);
h->block_rsv = &fs_info->trans_block_rsv;
h->bytes_reserved = num_bytes;
h->reloc_reserved = reloc_reserved;
}
got_it:
if (!current->journal_info)
current->journal_info = h;
/*
* If the space_info is marked ALLOC_FORCE then we'll get upgraded to
* ALLOC_FORCE the first run through, and then we won't allocate for
* anybody else who races in later. We don't care about the return
* value here.
*/
if (do_chunk_alloc && num_bytes) {
u64 flags = h->block_rsv->space_info->flags;
btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
CHUNK_ALLOC_NO_FORCE);
}
/*
* btrfs_record_root_in_trans() needs to alloc new extents, and may
* call btrfs_join_transaction() while we're also starting a
* transaction.
*
* Thus it need to be called after current->journal_info initialized,
* or we can deadlock.
*/
ret = btrfs_record_root_in_trans(h, root);
if (ret) {
/*
* The transaction handle is fully initialized and linked with
* other structures so it needs to be ended in case of errors,
* not just freed.
*/
btrfs_end_transaction(h);
return ERR_PTR(ret);
}
return h;
join_fail:
if (type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
kmem_cache_free(btrfs_trans_handle_cachep, h);
alloc_fail:
if (num_bytes)
btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
num_bytes, NULL);
reserve_fail:
btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
return ERR_PTR(ret);
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
unsigned int num_items)
{
return start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_ALL, true);
}
struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
struct btrfs_root *root,
unsigned int num_items)
{
return start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
}
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
true);
}
struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
BTRFS_RESERVE_NO_FLUSH, true);
}
/*
* Similar to regular join but it never starts a transaction when none is
* running or after waiting for the current one to finish.
*/
struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOSTART,
BTRFS_RESERVE_NO_FLUSH, true);
}
/*
* btrfs_attach_transaction() - catch the running transaction
*
* It is used when we want to commit the current the transaction, but
* don't want to start a new one.
*
* Note: If this function return -ENOENT, it just means there is no
* running transaction. But it is possible that the inactive transaction
* is still in the memory, not fully on disk. If you hope there is no
* inactive transaction in the fs when -ENOENT is returned, you should
* invoke
* btrfs_attach_transaction_barrier()
*/
struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_ATTACH,
BTRFS_RESERVE_NO_FLUSH, true);
}
/*
* btrfs_attach_transaction_barrier() - catch the running transaction
*
* It is similar to the above function, the difference is this one
* will wait for all the inactive transactions until they fully
* complete.
*/
struct btrfs_trans_handle *
btrfs_attach_transaction_barrier(struct btrfs_root *root)
{
struct btrfs_trans_handle *trans;
trans = start_transaction(root, 0, TRANS_ATTACH,
BTRFS_RESERVE_NO_FLUSH, true);
if (trans == ERR_PTR(-ENOENT))
btrfs_wait_for_commit(root->fs_info, 0);
return trans;
}
/* Wait for a transaction commit to reach at least the given state. */
static noinline void wait_for_commit(struct btrfs_transaction *commit,
const enum btrfs_trans_state min_state)
{
struct btrfs_fs_info *fs_info = commit->fs_info;
u64 transid = commit->transid;
bool put = false;
/*
* At the moment this function is called with min_state either being
* TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
*/
if (min_state == TRANS_STATE_COMPLETED)
btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
else
btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
while (1) {
wait_event(commit->commit_wait, commit->state >= min_state);
if (put)
btrfs_put_transaction(commit);
if (min_state < TRANS_STATE_COMPLETED)
break;
/*
* A transaction isn't really completed until all of the
* previous transactions are completed, but with fsync we can
* end up with SUPER_COMMITTED transactions before a COMPLETED
* transaction. Wait for those.
*/
spin_lock(&fs_info->trans_lock);
commit = list_first_entry_or_null(&fs_info->trans_list,
struct btrfs_transaction,
list);
if (!commit || commit->transid > transid) {
spin_unlock(&fs_info->trans_lock);
break;
}
refcount_inc(&commit->use_count);
put = true;
spin_unlock(&fs_info->trans_lock);
}
}
int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
{
struct btrfs_transaction *cur_trans = NULL, *t;
int ret = 0;
if (transid) {
if (transid <= fs_info->last_trans_committed)
goto out;
/* find specified transaction */
spin_lock(&fs_info->trans_lock);
list_for_each_entry(t, &fs_info->trans_list, list) {
if (t->transid == transid) {
cur_trans = t;
refcount_inc(&cur_trans->use_count);
ret = 0;
break;
}
if (t->transid > transid) {
ret = 0;
break;
}
}
spin_unlock(&fs_info->trans_lock);
/*
* The specified transaction doesn't exist, or we
* raced with btrfs_commit_transaction
*/
if (!cur_trans) {
if (transid > fs_info->last_trans_committed)
ret = -EINVAL;
goto out;
}
} else {
/* find newest transaction that is committing | committed */
spin_lock(&fs_info->trans_lock);
list_for_each_entry_reverse(t, &fs_info->trans_list,
list) {
if (t->state >= TRANS_STATE_COMMIT_START) {
if (t->state == TRANS_STATE_COMPLETED)
break;
cur_trans = t;
refcount_inc(&cur_trans->use_count);
break;
}
}
spin_unlock(&fs_info->trans_lock);
if (!cur_trans)
goto out; /* nothing committing|committed */
}
wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
btrfs_put_transaction(cur_trans);
out:
return ret;
}
void btrfs_throttle(struct btrfs_fs_info *fs_info)
{
wait_current_trans(fs_info);
}
bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_transaction *cur_trans = trans->transaction;
if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
return true;
if (btrfs_check_space_for_delayed_refs(trans->fs_info))
return true;
return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
}
static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
if (!trans->block_rsv) {
ASSERT(!trans->bytes_reserved);
return;
}
if (!trans->bytes_reserved)
return;
ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid, trans->bytes_reserved, 0);
btrfs_block_rsv_release(fs_info, trans->block_rsv,
trans->bytes_reserved, NULL);
trans->bytes_reserved = 0;
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
int throttle)
{
struct btrfs_fs_info *info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
int err = 0;
if (refcount_read(&trans->use_count) > 1) {
refcount_dec(&trans->use_count);
trans->block_rsv = trans->orig_rsv;
return 0;
}
btrfs_trans_release_metadata(trans);
trans->block_rsv = NULL;
btrfs_create_pending_block_groups(trans);
btrfs_trans_release_chunk_metadata(trans);
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(info->sb);
WARN_ON(cur_trans != info->running_transaction);
WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
atomic_dec(&cur_trans->num_writers);
extwriter_counter_dec(cur_trans, trans->type);
cond_wake_up(&cur_trans->writer_wait);
btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(info, btrfs_trans_num_writers);
btrfs_put_transaction(cur_trans);
if (current->journal_info == trans)
current->journal_info = NULL;
if (throttle)
btrfs_run_delayed_iputs(info);
if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
wake_up_process(info->transaction_kthread);
if (TRANS_ABORTED(trans))
err = trans->aborted;
else
err = -EROFS;
}
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return err;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans)
{
return __btrfs_end_transaction(trans, 0);
}
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
{
return __btrfs_end_transaction(trans, 1);
}
/*
* when btree blocks are allocated, they have some corresponding bits set for
* them in one of two extent_io trees. This is used to make sure all of
* those extents are sent to disk but does not wait on them
*/
int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages, int mark)
{
int err = 0;
int werr = 0;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
struct extent_state *cached_state = NULL;
u64 start = 0;
u64 end;
while (!find_first_extent_bit(dirty_pages, start, &start, &end,
mark, &cached_state)) {
bool wait_writeback = false;
err = convert_extent_bit(dirty_pages, start, end,
EXTENT_NEED_WAIT,
mark, &cached_state);
/*
* convert_extent_bit can return -ENOMEM, which is most of the
* time a temporary error. So when it happens, ignore the error
* and wait for writeback of this range to finish - because we
* failed to set the bit EXTENT_NEED_WAIT for the range, a call
* to __btrfs_wait_marked_extents() would not know that
* writeback for this range started and therefore wouldn't
* wait for it to finish - we don't want to commit a
* superblock that points to btree nodes/leafs for which
* writeback hasn't finished yet (and without errors).
* We cleanup any entries left in the io tree when committing
* the transaction (through extent_io_tree_release()).
*/
if (err == -ENOMEM) {
err = 0;
wait_writeback = true;
}
if (!err)
err = filemap_fdatawrite_range(mapping, start, end);
if (err)
werr = err;
else if (wait_writeback)
werr = filemap_fdatawait_range(mapping, start, end);
free_extent_state(cached_state);
cached_state = NULL;
cond_resched();
start = end + 1;
}
return werr;
}
/*
* when btree blocks are allocated, they have some corresponding bits set for
* them in one of two extent_io trees. This is used to make sure all of
* those extents are on disk for transaction or log commit. We wait
* on all the pages and clear them from the dirty pages state tree
*/
static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages)
{
int err = 0;
int werr = 0;
struct address_space *mapping = fs_info->btree_inode->i_mapping;
struct extent_state *cached_state = NULL;
u64 start = 0;
u64 end;
while (!find_first_extent_bit(dirty_pages, start, &start, &end,
EXTENT_NEED_WAIT, &cached_state)) {
/*
* Ignore -ENOMEM errors returned by clear_extent_bit().
* When committing the transaction, we'll remove any entries
* left in the io tree. For a log commit, we don't remove them
* after committing the log because the tree can be accessed
* concurrently - we do it only at transaction commit time when
* it's safe to do it (through extent_io_tree_release()).
*/
err = clear_extent_bit(dirty_pages, start, end,
EXTENT_NEED_WAIT, &cached_state);
if (err == -ENOMEM)
err = 0;
if (!err)
err = filemap_fdatawait_range(mapping, start, end);
if (err)
werr = err;
free_extent_state(cached_state);
cached_state = NULL;
cond_resched();
start = end + 1;
}
if (err)
werr = err;
return werr;
}
static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
struct extent_io_tree *dirty_pages)
{
bool errors = false;
int err;
err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
errors = true;
if (errors && !err)
err = -EIO;
return err;
}
int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
{
struct btrfs_fs_info *fs_info = log_root->fs_info;
struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
bool errors = false;
int err;
ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
if ((mark & EXTENT_DIRTY) &&
test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
errors = true;
if ((mark & EXTENT_NEW) &&
test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
errors = true;
if (errors && !err)
err = -EIO;
return err;
}
/*
* When btree blocks are allocated the corresponding extents are marked dirty.
* This function ensures such extents are persisted on disk for transaction or
* log commit.
*
* @trans: transaction whose dirty pages we'd like to write
*/
static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
{
int ret;
int ret2;
struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
struct btrfs_fs_info *fs_info = trans->fs_info;
struct blk_plug plug;
blk_start_plug(&plug);
ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
blk_finish_plug(&plug);
ret2 = btrfs_wait_extents(fs_info, dirty_pages);
extent_io_tree_release(&trans->transaction->dirty_pages);
if (ret)
return ret;
else if (ret2)
return ret2;
else
return 0;
}
/*
* this is used to update the root pointer in the tree of tree roots.
*
* But, in the case of the extent allocation tree, updating the root
* pointer may allocate blocks which may change the root of the extent
* allocation tree.
*
* So, this loops and repeats and makes sure the cowonly root didn't
* change while the root pointer was being updated in the metadata.
*/
static int update_cowonly_root(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
u64 old_root_bytenr;
u64 old_root_used;
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_root *tree_root = fs_info->tree_root;
old_root_used = btrfs_root_used(&root->root_item);
while (1) {
old_root_bytenr = btrfs_root_bytenr(&root->root_item);
if (old_root_bytenr == root->node->start &&
old_root_used == btrfs_root_used(&root->root_item))
break;
btrfs_set_root_node(&root->root_item, root->node);
ret = btrfs_update_root(trans, tree_root,
&root->root_key,
&root->root_item);
if (ret)
return ret;
old_root_used = btrfs_root_used(&root->root_item);
}
return 0;
}
/*
* update all the cowonly tree roots on disk
*
* The error handling in this function may not be obvious. Any of the
* failures will cause the file system to go offline. We still need
* to clean up the delayed refs.
*/
static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
struct list_head *io_bgs = &trans->transaction->io_bgs;
struct list_head *next;
struct extent_buffer *eb;
int ret;
/*
* At this point no one can be using this transaction to modify any tree
* and no one can start another transaction to modify any tree either.
*/
ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
eb = btrfs_lock_root_node(fs_info->tree_root);
ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
0, &eb, BTRFS_NESTING_COW);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
if (ret)
return ret;
ret = btrfs_run_dev_stats(trans);
if (ret)
return ret;
ret = btrfs_run_dev_replace(trans);
if (ret)
return ret;
ret = btrfs_run_qgroups(trans);
if (ret)
return ret;
ret = btrfs_setup_space_cache(trans);
if (ret)
return ret;
again:
while (!list_empty(&fs_info->dirty_cowonly_roots)) {
struct btrfs_root *root;
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
clear_bit(BTRFS_ROOT_DIRTY, &root->state);
list_add_tail(&root->dirty_list,
&trans->transaction->switch_commits);
ret = update_cowonly_root(trans, root);
if (ret)
return ret;
}
/* Now flush any delayed refs generated by updating all of the roots */
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
ret = btrfs_write_dirty_block_groups(trans);
if (ret)
return ret;
/*
* We're writing the dirty block groups, which could generate
* delayed refs, which could generate more dirty block groups,
* so we want to keep this flushing in this loop to make sure
* everything gets run.
*/
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
return ret;
}
if (!list_empty(&fs_info->dirty_cowonly_roots))
goto again;
/* Update dev-replace pointer once everything is committed */
fs_info->dev_replace.committed_cursor_left =
fs_info->dev_replace.cursor_left_last_write_of_item;
return 0;
}
/*
* If we had a pending drop we need to see if there are any others left in our
* dead roots list, and if not clear our bit and wake any waiters.
*/
void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
{
/*
* We put the drop in progress roots at the front of the list, so if the
* first entry doesn't have UNFINISHED_DROP set we can wake everybody
* up.
*/
spin_lock(&fs_info->trans_lock);
if (!list_empty(&fs_info->dead_roots)) {
struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
struct btrfs_root,
root_list);
if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
spin_unlock(&fs_info->trans_lock);
return;
}
}
spin_unlock(&fs_info->trans_lock);
btrfs_wake_unfinished_drop(fs_info);
}
/*
* dead roots are old snapshots that need to be deleted. This allocates
* a dirty root struct and adds it into the list of dead roots that need to
* be deleted
*/
void btrfs_add_dead_root(struct btrfs_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
spin_lock(&fs_info->trans_lock);
if (list_empty(&root->root_list)) {
btrfs_grab_root(root);
/* We want to process the partially complete drops first. */
if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
list_add(&root->root_list, &fs_info->dead_roots);
else
list_add_tail(&root->root_list, &fs_info->dead_roots);
}
spin_unlock(&fs_info->trans_lock);
}
/*
* Update each subvolume root and its relocation root, if it exists, in the tree
* of tree roots. Also free log roots if they exist.
*/
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_root *gang[8];
int i;
int ret;
/*
* At this point no one can be using this transaction to modify any tree
* and no one can start another transaction to modify any tree either.
*/
ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
spin_lock(&fs_info->fs_roots_radix_lock);
while (1) {
ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
(void **)gang, 0,
ARRAY_SIZE(gang),
BTRFS_ROOT_TRANS_TAG);
if (ret == 0)
break;
for (i = 0; i < ret; i++) {
struct btrfs_root *root = gang[i];
int ret2;
/*
* At this point we can neither have tasks logging inodes
* from a root nor trying to commit a log tree.
*/
ASSERT(atomic_read(&root->log_writers) == 0);
ASSERT(atomic_read(&root->log_commit[0]) == 0);
ASSERT(atomic_read(&root->log_commit[1]) == 0);
radix_tree_tag_clear(&fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&fs_info->fs_roots_radix_lock);
btrfs_free_log(trans, root);
ret2 = btrfs_update_reloc_root(trans, root);
if (ret2)
return ret2;
/* see comments in should_cow_block() */
clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
smp_mb__after_atomic();
if (root->commit_root != root->node) {
list_add_tail(&root->dirty_list,
&trans->transaction->switch_commits);
btrfs_set_root_node(&root->root_item,
root->node);
}
ret2 = btrfs_update_root(trans, fs_info->tree_root,
&root->root_key,
&root->root_item);
if (ret2)
return ret2;
spin_lock(&fs_info->fs_roots_radix_lock);
btrfs_qgroup_free_meta_all_pertrans(root);
}
}
spin_unlock(&fs_info->fs_roots_radix_lock);
return 0;
}
/*
* defrag a given btree.
* Every leaf in the btree is read and defragged.
*/
int btrfs_defrag_root(struct btrfs_root *root)
{
struct btrfs_fs_info *info = root->fs_info;
struct btrfs_trans_handle *trans;
int ret;
if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
return 0;
while (1) {
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
break;
}
ret = btrfs_defrag_leaves(trans, root);
btrfs_end_transaction(trans);
btrfs_btree_balance_dirty(info);
cond_resched();
if (btrfs_fs_closing(info) || ret != -EAGAIN)
break;
if (btrfs_defrag_cancelled(info)) {
btrfs_debug(info, "defrag_root cancelled");
ret = -EAGAIN;
break;
}
}
clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
return ret;
}
/*
* Do all special snapshot related qgroup dirty hack.
*
* Will do all needed qgroup inherit and dirty hack like switch commit
* roots inside one transaction and write all btree into disk, to make
* qgroup works.
*/
static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_root *src,
struct btrfs_root *parent,
struct btrfs_qgroup_inherit *inherit,
u64 dst_objectid)
{
struct btrfs_fs_info *fs_info = src->fs_info;
int ret;
/*
* Save some performance in the case that qgroups are not
* enabled. If this check races with the ioctl, rescan will
* kick in anyway.
*/
if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
return 0;
/*
* Ensure dirty @src will be committed. Or, after coming
* commit_fs_roots() and switch_commit_roots(), any dirty but not
* recorded root will never be updated again, causing an outdated root
* item.
*/
ret = record_root_in_trans(trans, src, 1);
if (ret)
return ret;
/*
* btrfs_qgroup_inherit relies on a consistent view of the usage for the
* src root, so we must run the delayed refs here.
*
* However this isn't particularly fool proof, because there's no
* synchronization keeping us from changing the tree after this point
* before we do the qgroup_inherit, or even from making changes while
* we're doing the qgroup_inherit. But that's a problem for the future,
* for now flush the delayed refs to narrow the race window where the
* qgroup counters could end up wrong.
*/
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret) {
btrfs_abort_transaction(trans, ret);
return ret;
}
ret = commit_fs_roots(trans);
if (ret)
goto out;
ret = btrfs_qgroup_account_extents(trans);
if (ret < 0)
goto out;
/* Now qgroup are all updated, we can inherit it to new qgroups */
ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
inherit);
if (ret < 0)
goto out;
/*
* Now we do a simplified commit transaction, which will:
* 1) commit all subvolume and extent tree
* To ensure all subvolume and extent tree have a valid
* commit_root to accounting later insert_dir_item()
* 2) write all btree blocks onto disk
* This is to make sure later btree modification will be cowed
* Or commit_root can be populated and cause wrong qgroup numbers
* In this simplified commit, we don't really care about other trees
* like chunk and root tree, as they won't affect qgroup.
* And we don't write super to avoid half committed status.
*/
ret = commit_cowonly_roots(trans);
if (ret)
goto out;
switch_commit_roots(trans);
ret = btrfs_write_and_wait_transaction(trans);
if (ret)
btrfs_handle_fs_error(fs_info, ret,
"Error while writing out transaction for qgroup");
out:
/*
* Force parent root to be updated, as we recorded it before so its
* last_trans == cur_transid.
* Or it won't be committed again onto disk after later
* insert_dir_item()
*/
if (!ret)
ret = record_root_in_trans(trans, parent, 1);
return ret;
}
/*
* new snapshots need to be created at a very specific time in the
* transaction commit. This does the actual creation.
*
* Note:
* If the error which may affect the commitment of the current transaction
* happens, we should return the error number. If the error which just affect
* the creation of the pending snapshots, just return 0.
*/
static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
struct btrfs_pending_snapshot *pending)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_key key;
struct btrfs_root_item *new_root_item;
struct btrfs_root *tree_root = fs_info->tree_root;
struct btrfs_root *root = pending->root;
struct btrfs_root *parent_root;
struct btrfs_block_rsv *rsv;
struct inode *parent_inode = pending->dir;
struct btrfs_path *path;
struct btrfs_dir_item *dir_item;
struct extent_buffer *tmp;
struct extent_buffer *old;
struct timespec64 cur_time;
int ret = 0;
u64 to_reserve = 0;
u64 index = 0;
u64 objectid;
u64 root_flags;
unsigned int nofs_flags;
struct fscrypt_name fname;
ASSERT(pending->path);
path = pending->path;
ASSERT(pending->root_item);
new_root_item = pending->root_item;
/*
* We're inside a transaction and must make sure that any potential
* allocations with GFP_KERNEL in fscrypt won't recurse back to
* filesystem.
*/
nofs_flags = memalloc_nofs_save();
pending->error = fscrypt_setup_filename(parent_inode,
&pending->dentry->d_name, 0,
&fname);
memalloc_nofs_restore(nofs_flags);
if (pending->error)
goto free_pending;
pending->error = btrfs_get_free_objectid(tree_root, &objectid);
if (pending->error)
goto free_fname;
/*
* Make qgroup to skip current new snapshot's qgroupid, as it is
* accounted by later btrfs_qgroup_inherit().
*/
btrfs_set_skip_qgroup(trans, objectid);
btrfs_reloc_pre_snapshot(pending, &to_reserve);
if (to_reserve > 0) {
pending->error = btrfs_block_rsv_add(fs_info,
&pending->block_rsv,
to_reserve,
BTRFS_RESERVE_NO_FLUSH);
if (pending->error)
goto clear_skip_qgroup;
}
key.objectid = objectid;
key.offset = (u64)-1;
key.type = BTRFS_ROOT_ITEM_KEY;
rsv = trans->block_rsv;
trans->block_rsv = &pending->block_rsv;
trans->bytes_reserved = trans->block_rsv->reserved;
trace_btrfs_space_reservation(fs_info, "transaction",
trans->transid,
trans->bytes_reserved, 1);
parent_root = BTRFS_I(parent_inode)->root;
ret = record_root_in_trans(trans, parent_root, 0);
if (ret)
goto fail;
cur_time = current_time(parent_inode);
/*
* insert the directory item
*/
ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
BUG_ON(ret); /* -ENOMEM */
/* check if there is a file/dir which has the same name. */
dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
btrfs_ino(BTRFS_I(parent_inode)),
&fname.disk_name, 0);
if (dir_item != NULL && !IS_ERR(dir_item)) {
pending->error = -EEXIST;
goto dir_item_existed;
} else if (IS_ERR(dir_item)) {
ret = PTR_ERR(dir_item);
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_release_path(path);
/*
* pull in the delayed directory update
* and the delayed inode item
* otherwise we corrupt the FS during
* snapshot
*/
ret = btrfs_run_delayed_items(trans);
if (ret) { /* Transaction aborted */
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = record_root_in_trans(trans, root, 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
btrfs_check_and_init_root_item(new_root_item);
root_flags = btrfs_root_flags(new_root_item);
if (pending->readonly)
root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
else
root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
btrfs_set_root_flags(new_root_item, root_flags);
btrfs_set_root_generation_v2(new_root_item,
trans->transid);
generate_random_guid(new_root_item->uuid);
memcpy(new_root_item->parent_uuid, root->root_item.uuid,
BTRFS_UUID_SIZE);
if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
memset(new_root_item->received_uuid, 0,
sizeof(new_root_item->received_uuid));
memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
btrfs_set_root_stransid(new_root_item, 0);
btrfs_set_root_rtransid(new_root_item, 0);
}
btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
btrfs_set_root_otransid(new_root_item, trans->transid);
old = btrfs_lock_root_node(root);
ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
BTRFS_NESTING_COW);
if (ret) {
btrfs_tree_unlock(old);
free_extent_buffer(old);
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
/* clean up in any case */
btrfs_tree_unlock(old);
free_extent_buffer(old);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/* see comments in should_cow_block() */
set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
smp_wmb();
btrfs_set_root_node(new_root_item, tmp);
/* record when the snapshot was created in key.offset */
key.offset = trans->transid;
ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
btrfs_tree_unlock(tmp);
free_extent_buffer(tmp);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/*
* insert root back/forward references
*/
ret = btrfs_add_root_ref(trans, objectid,
parent_root->root_key.objectid,
btrfs_ino(BTRFS_I(parent_inode)), index,
&fname.disk_name);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
key.offset = (u64)-1;
pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
if (IS_ERR(pending->snap)) {
ret = PTR_ERR(pending->snap);
pending->snap = NULL;
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_reloc_post_snapshot(trans, pending);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
/*
* Do special qgroup accounting for snapshot, as we do some qgroup
* snapshot hack to do fast snapshot.
* To co-operate with that hack, we do hack again.
* Or snapshot will be greatly slowed down by a subtree qgroup rescan
*/
ret = qgroup_account_snapshot(trans, root, parent_root,
pending->inherit, objectid);
if (ret < 0)
goto fail;
ret = btrfs_insert_dir_item(trans, &fname.disk_name,
BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
index);
/* We have check then name at the beginning, so it is impossible. */
BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
fname.disk_name.len * 2);
parent_inode->i_mtime = current_time(parent_inode);
parent_inode->i_ctime = parent_inode->i_mtime;
ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
BTRFS_UUID_KEY_SUBVOL,
objectid);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
BTRFS_UUID_KEY_RECEIVED_SUBVOL,
objectid);
if (ret && ret != -EEXIST) {
btrfs_abort_transaction(trans, ret);
goto fail;
}
}
fail:
pending->error = ret;
dir_item_existed:
trans->block_rsv = rsv;
trans->bytes_reserved = 0;
clear_skip_qgroup:
btrfs_clear_skip_qgroup(trans);
free_fname:
fscrypt_free_filename(&fname);
free_pending:
kfree(new_root_item);
pending->root_item = NULL;
btrfs_free_path(path);
pending->path = NULL;
return ret;
}
/*
* create all the snapshots we've scheduled for creation
*/
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
{
struct btrfs_pending_snapshot *pending, *next;
struct list_head *head = &trans->transaction->pending_snapshots;
int ret = 0;
list_for_each_entry_safe(pending, next, head, list) {
list_del(&pending->list);
ret = create_pending_snapshot(trans, pending);
if (ret)
break;
}
return ret;
}
static void update_super_roots(struct btrfs_fs_info *fs_info)
{
struct btrfs_root_item *root_item;
struct btrfs_super_block *super;
super = fs_info->super_copy;
root_item = &fs_info->chunk_root->root_item;
super->chunk_root = root_item->bytenr;
super->chunk_root_generation = root_item->generation;
super->chunk_root_level = root_item->level;
root_item = &fs_info->tree_root->root_item;
super->root = root_item->bytenr;
super->generation = root_item->generation;
super->root_level = root_item->level;
if (btrfs_test_opt(fs_info, SPACE_CACHE))
super->cache_generation = root_item->generation;
else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
super->cache_generation = 0;
if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
super->uuid_tree_generation = root_item->generation;
}
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
struct btrfs_transaction *trans;
int ret = 0;
spin_lock(&info->trans_lock);
trans = info->running_transaction;
if (trans)
ret = (trans->state >= TRANS_STATE_COMMIT_START);
spin_unlock(&info->trans_lock);
return ret;
}
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
struct btrfs_transaction *trans;
int ret = 0;
spin_lock(&info->trans_lock);
trans = info->running_transaction;
if (trans)
ret = is_transaction_blocked(trans);
spin_unlock(&info->trans_lock);
return ret;
}
void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans;
/* Kick the transaction kthread. */
set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
wake_up_process(fs_info->transaction_kthread);
/* take transaction reference */
cur_trans = trans->transaction;
refcount_inc(&cur_trans->use_count);
btrfs_end_transaction(trans);
/*
* Wait for the current transaction commit to start and block
* subsequent transaction joins
*/
btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
wait_event(fs_info->transaction_blocked_wait,
cur_trans->state >= TRANS_STATE_COMMIT_START ||
TRANS_ABORTED(cur_trans));
btrfs_put_transaction(cur_trans);
}
static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
WARN_ON(refcount_read(&trans->use_count) > 1);
btrfs_abort_transaction(trans, err);
spin_lock(&fs_info->trans_lock);
/*
* If the transaction is removed from the list, it means this
* transaction has been committed successfully, so it is impossible
* to call the cleanup function.
*/
BUG_ON(list_empty(&cur_trans->list));
if (cur_trans == fs_info->running_transaction) {
cur_trans->state = TRANS_STATE_COMMIT_DOING;
spin_unlock(&fs_info->trans_lock);
/*
* The thread has already released the lockdep map as reader
* already in btrfs_commit_transaction().
*/
btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
spin_lock(&fs_info->trans_lock);
}
/*
* Now that we know no one else is still using the transaction we can
* remove the transaction from the list of transactions. This avoids
* the transaction kthread from cleaning up the transaction while some
* other task is still using it, which could result in a use-after-free
* on things like log trees, as it forces the transaction kthread to
* wait for this transaction to be cleaned up by us.
*/
list_del_init(&cur_trans->list);
spin_unlock(&fs_info->trans_lock);
btrfs_cleanup_one_transaction(trans->transaction, fs_info);
spin_lock(&fs_info->trans_lock);
if (cur_trans == fs_info->running_transaction)
fs_info->running_transaction = NULL;
spin_unlock(&fs_info->trans_lock);
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
btrfs_put_transaction(cur_trans);
btrfs_put_transaction(cur_trans);
trace_btrfs_transaction_commit(fs_info);
if (current->journal_info == trans)
current->journal_info = NULL;
/*
* If relocation is running, we can't cancel scrub because that will
* result in a deadlock. Before relocating a block group, relocation
* pauses scrub, then starts and commits a transaction before unpausing
* scrub. If the transaction commit is being done by the relocation
* task or triggered by another task and the relocation task is waiting
* for the commit, and we end up here due to an error in the commit
* path, then calling btrfs_scrub_cancel() will deadlock, as we are
* asking for scrub to stop while having it asked to be paused higher
* above in relocation code.
*/
if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
btrfs_scrub_cancel(fs_info);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
}
/*
* Release reserved delayed ref space of all pending block groups of the
* transaction and remove them from the list
*/
static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_block_group *block_group, *tmp;
list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
btrfs_delayed_refs_rsv_release(fs_info, 1);
list_del_init(&block_group->bg_list);
}
}
static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
{
/*
* We use try_to_writeback_inodes_sb() here because if we used
* btrfs_start_delalloc_roots we would deadlock with fs freeze.
* Currently are holding the fs freeze lock, if we do an async flush
* we'll do btrfs_join_transaction() and deadlock because we need to
* wait for the fs freeze lock. Using the direct flushing we benefit
* from already being in a transaction and our join_transaction doesn't
* have to re-take the fs freeze lock.
*
* Note that try_to_writeback_inodes_sb() will only trigger writeback
* if it can read lock sb->s_umount. It will always be able to lock it,
* except when the filesystem is being unmounted or being frozen, but in
* those cases sync_filesystem() is called, which results in calling
* writeback_inodes_sb() while holding a write lock on sb->s_umount.
* Note that we don't call writeback_inodes_sb() directly, because it
* will emit a warning if sb->s_umount is not locked.
*/
if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
return 0;
}
static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
{
if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
}
/*
* Add a pending snapshot associated with the given transaction handle to the
* respective handle. This must be called after the transaction commit started
* and while holding fs_info->trans_lock.
* This serves to guarantee a caller of btrfs_commit_transaction() that it can
* safely free the pending snapshot pointer in case btrfs_commit_transaction()
* returns an error.
*/
static void add_pending_snapshot(struct btrfs_trans_handle *trans)
{
struct btrfs_transaction *cur_trans = trans->transaction;
if (!trans->pending_snapshot)
return;
lockdep_assert_held(&trans->fs_info->trans_lock);
ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START);
list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
}
static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
{
fs_info->commit_stats.commit_count++;
fs_info->commit_stats.last_commit_dur = interval;
fs_info->commit_stats.max_commit_dur =
max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
fs_info->commit_stats.total_commit_dur += interval;
}
int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_transaction *prev_trans = NULL;
int ret;
ktime_t start_time;
ktime_t interval;
ASSERT(refcount_read(&trans->use_count) == 1);
btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
/* Stop the commit early if ->aborted is set */
if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
goto lockdep_trans_commit_start_release;
}
btrfs_trans_release_metadata(trans);
trans->block_rsv = NULL;
/*
* We only want one transaction commit doing the flushing so we do not
* waste a bunch of time on lock contention on the extent root node.
*/
if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
&cur_trans->delayed_refs.flags)) {
/*
* Make a pass through all the delayed refs we have so far.
* Any running threads may add more while we are here.
*/
ret = btrfs_run_delayed_refs(trans, 0);
if (ret)
goto lockdep_trans_commit_start_release;
}
btrfs_create_pending_block_groups(trans);
if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
int run_it = 0;
/* this mutex is also taken before trying to set
* block groups readonly. We need to make sure
* that nobody has set a block group readonly
* after a extents from that block group have been
* allocated for cache files. btrfs_set_block_group_ro
* will wait for the transaction to commit if it
* finds BTRFS_TRANS_DIRTY_BG_RUN set.
*
* The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
* only one process starts all the block group IO. It wouldn't
* hurt to have more than one go through, but there's no
* real advantage to it either.
*/
mutex_lock(&fs_info->ro_block_group_mutex);
if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
&cur_trans->flags))
run_it = 1;
mutex_unlock(&fs_info->ro_block_group_mutex);
if (run_it) {
ret = btrfs_start_dirty_block_groups(trans);
if (ret)
goto lockdep_trans_commit_start_release;
}
}
spin_lock(&fs_info->trans_lock);
if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
add_pending_snapshot(trans);
spin_unlock(&fs_info->trans_lock);
refcount_inc(&cur_trans->use_count);
if (trans->in_fsync)
want_state = TRANS_STATE_SUPER_COMMITTED;
btrfs_trans_state_lockdep_release(fs_info,
BTRFS_LOCKDEP_TRANS_COMMIT_START);
ret = btrfs_end_transaction(trans);
wait_for_commit(cur_trans, want_state);
if (TRANS_ABORTED(cur_trans))
ret = cur_trans->aborted;
btrfs_put_transaction(cur_trans);
return ret;
}
cur_trans->state = TRANS_STATE_COMMIT_START;
wake_up(&fs_info->transaction_blocked_wait);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
if (cur_trans->list.prev != &fs_info->trans_list) {
enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
if (trans->in_fsync)
want_state = TRANS_STATE_SUPER_COMMITTED;
prev_trans = list_entry(cur_trans->list.prev,
struct btrfs_transaction, list);
if (prev_trans->state < want_state) {
refcount_inc(&prev_trans->use_count);
spin_unlock(&fs_info->trans_lock);
wait_for_commit(prev_trans, want_state);
ret = READ_ONCE(prev_trans->aborted);
btrfs_put_transaction(prev_trans);
if (ret)
goto lockdep_release;
} else {
spin_unlock(&fs_info->trans_lock);
}
} else {
spin_unlock(&fs_info->trans_lock);
/*
* The previous transaction was aborted and was already removed
* from the list of transactions at fs_info->trans_list. So we
* abort to prevent writing a new superblock that reflects a
* corrupt state (pointing to trees with unwritten nodes/leafs).
*/
if (BTRFS_FS_ERROR(fs_info)) {
ret = -EROFS;
goto lockdep_release;
}
}
/*
* Get the time spent on the work done by the commit thread and not
* the time spent waiting on a previous commit
*/
start_time = ktime_get_ns();
extwriter_counter_dec(cur_trans, trans->type);
ret = btrfs_start_delalloc_flush(fs_info);
if (ret)
goto lockdep_release;
ret = btrfs_run_delayed_items(trans);
if (ret)
goto lockdep_release;
/*
* The thread has started/joined the transaction thus it holds the
* lockdep map as a reader. It has to release it before acquiring the
* lockdep map as a writer.
*/
btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
wait_event(cur_trans->writer_wait,
extwriter_counter_read(cur_trans) == 0);
/* some pending stuffs might be added after the previous flush. */
ret = btrfs_run_delayed_items(trans);
if (ret) {
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
goto cleanup_transaction;
}
btrfs_wait_delalloc_flush(fs_info);
/*
* Wait for all ordered extents started by a fast fsync that joined this
* transaction. Otherwise if this transaction commits before the ordered
* extents complete we lose logged data after a power failure.
*/
btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
wait_event(cur_trans->pending_wait,
atomic_read(&cur_trans->pending_ordered) == 0);
btrfs_scrub_pause(fs_info);
/*
* Ok now we need to make sure to block out any other joins while we
* commit the transaction. We could have started a join before setting
* COMMIT_DOING so make sure to wait for num_writers to == 1 again.
*/
spin_lock(&fs_info->trans_lock);
add_pending_snapshot(trans);
cur_trans->state = TRANS_STATE_COMMIT_DOING;
spin_unlock(&fs_info->trans_lock);
/*
* The thread has started/joined the transaction thus it holds the
* lockdep map as a reader. It has to release it before acquiring the
* lockdep map as a writer.
*/
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
/*
* Make lockdep happy by acquiring the state locks after
* btrfs_trans_num_writers is released. If we acquired the state locks
* before releasing the btrfs_trans_num_writers lock then lockdep would
* complain because we did not follow the reverse order unlocking rule.
*/
btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
/*
* We've started the commit, clear the flag in case we were triggered to
* do an async commit but somebody else started before the transaction
* kthread could do the work.
*/
clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
goto scrub_continue;
}
/*
* the reloc mutex makes sure that we stop
* the balancing code from coming in and moving
* extents around in the middle of the commit
*/
mutex_lock(&fs_info->reloc_mutex);
/*
* We needn't worry about the delayed items because we will
* deal with them in create_pending_snapshot(), which is the
* core function of the snapshot creation.
*/
ret = create_pending_snapshots(trans);
if (ret)
goto unlock_reloc;
/*
* We insert the dir indexes of the snapshots and update the inode
* of the snapshots' parents after the snapshot creation, so there
* are some delayed items which are not dealt with. Now deal with
* them.
*
* We needn't worry that this operation will corrupt the snapshots,
* because all the tree which are snapshoted will be forced to COW
* the nodes and leaves.
*/
ret = btrfs_run_delayed_items(trans);
if (ret)
goto unlock_reloc;
ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
if (ret)
goto unlock_reloc;
/*
* make sure none of the code above managed to slip in a
* delayed item
*/
btrfs_assert_delayed_root_empty(fs_info);
WARN_ON(cur_trans != trans->transaction);
ret = commit_fs_roots(trans);
if (ret)
goto unlock_reloc;
/* commit_fs_roots gets rid of all the tree log roots, it is now
* safe to free the root of tree log roots
*/
btrfs_free_log_root_tree(trans, fs_info);
/*
* Since fs roots are all committed, we can get a quite accurate
* new_roots. So let's do quota accounting.
*/
ret = btrfs_qgroup_account_extents(trans);
if (ret < 0)
goto unlock_reloc;
ret = commit_cowonly_roots(trans);
if (ret)
goto unlock_reloc;
/*
* The tasks which save the space cache and inode cache may also
* update ->aborted, check it.
*/
if (TRANS_ABORTED(cur_trans)) {
ret = cur_trans->aborted;
goto unlock_reloc;
}
cur_trans = fs_info->running_transaction;
btrfs_set_root_node(&fs_info->tree_root->root_item,
fs_info->tree_root->node);
list_add_tail(&fs_info->tree_root->dirty_list,
&cur_trans->switch_commits);
btrfs_set_root_node(&fs_info->chunk_root->root_item,
fs_info->chunk_root->node);
list_add_tail(&fs_info->chunk_root->dirty_list,
&cur_trans->switch_commits);
if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
btrfs_set_root_node(&fs_info->block_group_root->root_item,
fs_info->block_group_root->node);
list_add_tail(&fs_info->block_group_root->dirty_list,
&cur_trans->switch_commits);
}
switch_commit_roots(trans);
ASSERT(list_empty(&cur_trans->dirty_bgs));
ASSERT(list_empty(&cur_trans->io_bgs));
update_super_roots(fs_info);
btrfs_set_super_log_root(fs_info->super_copy, 0);
btrfs_set_super_log_root_level(fs_info->super_copy, 0);
memcpy(fs_info->super_for_commit, fs_info->super_copy,
sizeof(*fs_info->super_copy));
btrfs_commit_device_sizes(cur_trans);
clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
btrfs_trans_release_chunk_metadata(trans);
/*
* Before changing the transaction state to TRANS_STATE_UNBLOCKED and
* setting fs_info->running_transaction to NULL, lock tree_log_mutex to
* make sure that before we commit our superblock, no other task can
* start a new transaction and commit a log tree before we commit our
* superblock. Anyone trying to commit a log tree locks this mutex before
* writing its superblock.
*/
mutex_lock(&fs_info->tree_log_mutex);
spin_lock(&fs_info->trans_lock);
cur_trans->state = TRANS_STATE_UNBLOCKED;
fs_info->running_transaction = NULL;
spin_unlock(&fs_info->trans_lock);
mutex_unlock(&fs_info->reloc_mutex);
wake_up(&fs_info->transaction_wait);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
/* If we have features changed, wake up the cleaner to update sysfs. */
if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
fs_info->cleaner_kthread)
wake_up_process(fs_info->cleaner_kthread);
ret = btrfs_write_and_wait_transaction(trans);
if (ret) {
btrfs_handle_fs_error(fs_info, ret,
"Error while writing out transaction");
mutex_unlock(&fs_info->tree_log_mutex);
goto scrub_continue;
}
ret = write_all_supers(fs_info, 0);
/*
* the super is written, we can safely allow the tree-loggers
* to go about their business
*/
mutex_unlock(&fs_info->tree_log_mutex);
if (ret)
goto scrub_continue;
/*
* We needn't acquire the lock here because there is no other task
* which can change it.
*/
cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
wake_up(&cur_trans->commit_wait);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
btrfs_finish_extent_commit(trans);
if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
btrfs_clear_space_info_full(fs_info);
fs_info->last_trans_committed = cur_trans->transid;
/*
* We needn't acquire the lock here because there is no other task
* which can change it.
*/
cur_trans->state = TRANS_STATE_COMPLETED;
wake_up(&cur_trans->commit_wait);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
spin_lock(&fs_info->trans_lock);
list_del_init(&cur_trans->list);
spin_unlock(&fs_info->trans_lock);
btrfs_put_transaction(cur_trans);
btrfs_put_transaction(cur_trans);
if (trans->type & __TRANS_FREEZABLE)
sb_end_intwrite(fs_info->sb);
trace_btrfs_transaction_commit(fs_info);
interval = ktime_get_ns() - start_time;
btrfs_scrub_continue(fs_info);
if (current->journal_info == trans)
current->journal_info = NULL;
kmem_cache_free(btrfs_trans_handle_cachep, trans);
update_commit_stats(fs_info, interval);
return ret;
unlock_reloc:
mutex_unlock(&fs_info->reloc_mutex);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
scrub_continue:
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
btrfs_scrub_continue(fs_info);
cleanup_transaction:
btrfs_trans_release_metadata(trans);
btrfs_cleanup_pending_block_groups(trans);
btrfs_trans_release_chunk_metadata(trans);
trans->block_rsv = NULL;
btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
if (current->journal_info == trans)
current->journal_info = NULL;
cleanup_transaction(trans, ret);
return ret;
lockdep_release:
btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
goto cleanup_transaction;
lockdep_trans_commit_start_release:
btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
btrfs_end_transaction(trans);
return ret;
}
/*
* return < 0 if error
* 0 if there are no more dead_roots at the time of call
* 1 there are more to be processed, call me again
*
* The return value indicates there are certainly more snapshots to delete, but
* if there comes a new one during processing, it may return 0. We don't mind,
* because btrfs_commit_super will poke cleaner thread and it will process it a
* few seconds later.
*/
int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
{
struct btrfs_root *root;
int ret;
spin_lock(&fs_info->trans_lock);
if (list_empty(&fs_info->dead_roots)) {
spin_unlock(&fs_info->trans_lock);
return 0;
}
root = list_first_entry(&fs_info->dead_roots,
struct btrfs_root, root_list);
list_del_init(&root->root_list);
spin_unlock(&fs_info->trans_lock);
btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
btrfs_kill_all_delayed_nodes(root);
if (btrfs_header_backref_rev(root->node) <
BTRFS_MIXED_BACKREF_REV)
ret = btrfs_drop_snapshot(root, 0, 0);
else
ret = btrfs_drop_snapshot(root, 1, 0);
btrfs_put_root(root);
return (ret < 0) ? 0 : 1;
}
/*
* We only mark the transaction aborted and then set the file system read-only.
* This will prevent new transactions from starting or trying to join this
* one.
*
* This means that error recovery at the call site is limited to freeing
* any local memory allocations and passing the error code up without
* further cleanup. The transaction should complete as it normally would
* in the call path but will return -EIO.
*
* We'll complete the cleanup in btrfs_end_transaction and
* btrfs_commit_transaction.
*/
void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
const char *function,
unsigned int line, int errno, bool first_hit)
{
struct btrfs_fs_info *fs_info = trans->fs_info;
WRITE_ONCE(trans->aborted, errno);
WRITE_ONCE(trans->transaction->aborted, errno);
if (first_hit && errno == -ENOSPC)
btrfs_dump_space_info_for_trans_abort(fs_info);
/* Wake up anybody who may be waiting on this transaction */
wake_up(&fs_info->transaction_wait);
wake_up(&fs_info->transaction_blocked_wait);
__btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
}
int __init btrfs_transaction_init(void)
{
btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
sizeof(struct btrfs_trans_handle), 0,
SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
if (!btrfs_trans_handle_cachep)
return -ENOMEM;
return 0;
}
void __cold btrfs_transaction_exit(void)
{
kmem_cache_destroy(btrfs_trans_handle_cachep);
}
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