/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/writeback.h>
#include <linux/pagemap.h>
#include <linux/blkdev.h>
#include <linux/uuid.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "locking.h"
#include "tree-log.h"
#include "inode-map.h"
#include "volumes.h"
#include "dev-replace.h"
#define BTRFS_ROOT_TRANS_TAG 0
void put_transaction(struct btrfs_transaction *transaction)
{
WARN_ON(atomic_read(&transaction->use_count) == 0);
if (atomic_dec_and_test(&transaction->use_count)) {
BUG_ON(!list_empty(&transaction->list));
WARN_ON(transaction->delayed_refs.root.rb_node);
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
}
static noinline void switch_commit_root(struct btrfs_root *root)
{
free_extent_buffer(root->commit_root);
root->commit_root = btrfs_root_node(root);
}
static inline int can_join_transaction(struct btrfs_transaction *trans,
int type)
{
return !(trans->in_commit &&
type != TRANS_JOIN &&
type != TRANS_JOIN_NOLOCK);
}
/*
* either allocate a new transaction or hop into the existing one
*/
static noinline int join_transaction(struct btrfs_root *root, int type)
{
struct btrfs_transaction *cur_trans;
struct btrfs_fs_info *fs_info = root->fs_info;
spin_lock(&fs_info->trans_lock);
loop:
/* The file system has been taken offline. No new transactions. */
if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
spin_unlock(&fs_info->trans_lock);
return -EROFS;
}
if (fs_info->trans_no_join) {
/*
* If we are JOIN_NOLOCK we're already committing a current
* transaction, we just need a handle to deal with something
* when committing the transaction, such as inode cache and
* space cache. It is a special case.
*/
if (type != TRANS_JOIN_NOLOCK) {
spin_unlock(&fs_info->trans_lock);
return -EBUSY;
}
}
cur_trans = fs_info->running_transaction;
if (cur_trans) {
if (cur_trans->aborted) {
spin_unlock(&fs_info->trans_lock);
return cur_trans->aborted;
}
if (!can_join_transaction(cur_trans, type)) {
spin_unlock(&fs_info->trans_lock);
return -EBUSY;
}
atomic_inc(&cur_trans->use_count);
atomic_inc(&cur_trans->num_writers);
cur_trans->num_joined++;
spin_unlock(&fs_info->trans_lock);
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;
cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
if (!cur_trans)
return -ENOMEM;
spin_lock(&fs_info->trans_lock);
if (fs_info->running_transaction) {
/*
* someone started a transaction after we unlocked. Make sure
* to redo the trans_no_join checks above
*/
kmem_cache_free(btrfs_transaction_cachep, cur_trans);
goto loop;
} else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
spin_unlock(&fs_info->trans_lock);
kmem_cache_free(btrfs_transaction_cachep, cur_trans);
return -EROFS;
}
atomic_set(&cur_trans->num_writers, 1);
cur_trans->num_joined = 0;
init_waitqueue_head(&cur_trans->writer_wait);
init_waitqueue_head(&cur_trans->commit_wait);
cur_trans->in_commit = 0;
cur_trans->blocked = 0;
/*
* One for this trans handle, one so it will live on until we
* commit the transaction.
*/
atomic_set(&cur_trans->use_count, 2);
cur_trans->commit_done = 0;
cur_trans->start_time = get_seconds();
cur_trans->delayed_refs.root = RB_ROOT;
cur_trans->delayed_refs.num_entries = 0;
cur_trans->delayed_refs.num_heads_ready = 0;
cur_trans->delayed_refs.num_heads = 0;
cur_trans->delayed_refs.flushing = 0;
cur_trans->delayed_refs.run_delayed_start = 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");
atomic_set(&fs_info->tree_mod_seq, 0);
spin_lock_init(&cur_trans->commit_lock);
spin_lock_init(&cur_trans->delayed_refs.lock);
atomic_set(&cur_trans->delayed_refs.procs_running_refs, 0);
atomic_set(&cur_trans->delayed_refs.ref_seq, 0);
init_waitqueue_head(&cur_trans->delayed_refs.wait);
INIT_LIST_HEAD(&cur_trans->pending_snapshots);
INIT_LIST_HEAD(&cur_trans->ordered_operations);
list_add_tail(&cur_trans->list, &fs_info->trans_list);
extent_io_tree_init(&cur_trans->dirty_pages,
fs_info->btree_inode->i_mapping);
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 reference
* counted 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)
{
if (root->ref_cows && root->last_trans < trans->transid) {
WARN_ON(root == root->fs_info->extent_root);
WARN_ON(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
*/
root->in_trans_setup = 1;
/* make sure readers find in_trans_setup before
* they find our root->last_trans update
*/
smp_wmb();
spin_lock(&root->fs_info->fs_roots_radix_lock);
if (root->last_trans == trans->transid) {
spin_unlock(&root->fs_info->fs_roots_radix_lock);
return 0;
}
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
spin_unlock(&root->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
*/
btrfs_init_reloc_root(trans, root);
smp_wmb();
root->in_trans_setup = 0;
}
return 0;
}
int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
if (!root->ref_cows)
return 0;
/*
* see record_root_in_trans for comments about in_trans_setup usage
* and barriers
*/
smp_rmb();
if (root->last_trans == trans->transid &&
!root->in_trans_setup)
return 0;
mutex_lock(&root->fs_info->reloc_mutex);
record_root_in_trans(trans, root);
mutex_unlock(&root->fs_info->reloc_mutex);
return 0;
}
/* 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_root *root)
{
struct btrfs_transaction *cur_trans;
spin_lock(&root->fs_info->trans_lock);
cur_trans = root->fs_info->running_transaction;
if (cur_trans && cur_trans->blocked) {
atomic_inc(&cur_trans->use_count);
spin_unlock(&root->fs_info->trans_lock);
wait_event(root->fs_info->transaction_wait,
!cur_trans->blocked);
put_transaction(cur_trans);
} else {
spin_unlock(&root->fs_info->trans_lock);
}
}
static int may_wait_transaction(struct btrfs_root *root, int type)
{
if (root->fs_info->log_root_recovering)
return 0;
if (type == TRANS_USERSPACE)
return 1;
if (type == TRANS_START &&
!atomic_read(&root->fs_info->open_ioctl_trans))
return 1;
return 0;
}
static struct btrfs_trans_handle *
start_transaction(struct btrfs_root *root, u64 num_items, int type,
enum btrfs_reserve_flush_enum flush)
{
struct btrfs_trans_handle *h;
struct btrfs_transaction *cur_trans;
u64 num_bytes = 0;
int ret;
u64 qgroup_reserved = 0;
if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
return ERR_PTR(-EROFS);
if (current->journal_info) {
WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
h = current->journal_info;
h->use_count++;
WARN_ON(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 > 0 && root != root->fs_info->chunk_root) {
if (root->fs_info->quota_enabled &&
is_fstree(root->root_key.objectid)) {
qgroup_reserved = num_items * root->leafsize;
ret = btrfs_qgroup_reserve(root, qgroup_reserved);
if (ret)
return ERR_PTR(ret);
}
num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
ret = btrfs_block_rsv_add(root,
&root->fs_info->trans_block_rsv,
num_bytes, flush);
if (ret)
goto reserve_fail;
}
again:
h = kmem_cache_alloc(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_JOIN_NOLOCK)
sb_start_intwrite(root->fs_info->sb);
if (may_wait_transaction(root, type))
wait_current_trans(root);
do {
ret = join_transaction(root, type);
if (ret == -EBUSY) {
wait_current_trans(root);
if (unlikely(type == TRANS_ATTACH))
ret = -ENOENT;
}
} while (ret == -EBUSY);
if (ret < 0) {
/* We must get the transaction if we are JOIN_NOLOCK. */
BUG_ON(type == TRANS_JOIN_NOLOCK);
goto join_fail;
}
cur_trans = root->fs_info->running_transaction;
h->transid = cur_trans->transid;
h->transaction = cur_trans;
h->blocks_used = 0;
h->bytes_reserved = 0;
h->root = root;
h->delayed_ref_updates = 0;
h->use_count = 1;
h->adding_csums = 0;
h->block_rsv = NULL;
h->orig_rsv = NULL;
h->aborted = 0;
h->qgroup_reserved = 0;
h->delayed_ref_elem.seq = 0;
h->type = type;
h->allocating_chunk = false;
INIT_LIST_HEAD(&h->qgroup_ref_list);
INIT_LIST_HEAD(&h->new_bgs);
smp_mb();
if (cur_trans->blocked && may_wait_transaction(root, type)) {
btrfs_commit_transaction(h, root);
goto again;
}
if (num_bytes) {
trace_btrfs_space_reservation(root->fs_info, "transaction",
h->transid, num_bytes, 1);
h->block_rsv = &root->fs_info->trans_block_rsv;
h->bytes_reserved = num_bytes;
}
h->qgroup_reserved = qgroup_reserved;
got_it:
btrfs_record_root_in_trans(h, root);
if (!current->journal_info && type != TRANS_USERSPACE)
current->journal_info = h;
return h;
join_fail:
if (type < TRANS_JOIN_NOLOCK)
sb_end_intwrite(root->fs_info->sb);
kmem_cache_free(btrfs_trans_handle_cachep, h);
alloc_fail:
if (num_bytes)
btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
num_bytes);
reserve_fail:
if (qgroup_reserved)
btrfs_qgroup_free(root, qgroup_reserved);
return ERR_PTR(ret);
}
struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
int num_items)
{
return start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_ALL);
}
struct btrfs_trans_handle *btrfs_start_transaction_lflush(
struct btrfs_root *root, int num_items)
{
return start_transaction(root, num_items, TRANS_START,
BTRFS_RESERVE_FLUSH_LIMIT);
}
struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN, 0);
}
struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0);
}
struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_USERSPACE, 0);
}
/*
* 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, 0);
}
/*
* btrfs_attach_transaction() - catch the running transaction
*
* It is similar to the above function, the differentia 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, 0);
if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
btrfs_wait_for_commit(root, 0);
return trans;
}
/* wait for a transaction commit to be fully complete */
static noinline void wait_for_commit(struct btrfs_root *root,
struct btrfs_transaction *commit)
{
wait_event(commit->commit_wait, commit->commit_done);
}
int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
{
struct btrfs_transaction *cur_trans = NULL, *t;
int ret = 0;
if (transid) {
if (transid <= root->fs_info->last_trans_committed)
goto out;
ret = -EINVAL;
/* find specified transaction */
spin_lock(&root->fs_info->trans_lock);
list_for_each_entry(t, &root->fs_info->trans_list, list) {
if (t->transid == transid) {
cur_trans = t;
atomic_inc(&cur_trans->use_count);
ret = 0;
break;
}
if (t->transid > transid) {
ret = 0;
break;
}
}
spin_unlock(&root->fs_info->trans_lock);
/* The specified transaction doesn't exist */
if (!cur_trans)
goto out;
} else {
/* find newest transaction that is committing | committed */
spin_lock(&root->fs_info->trans_lock);
list_for_each_entry_reverse(t, &root->fs_info->trans_list,
list) {
if (t->in_commit) {
if (t->commit_done)
break;
cur_trans = t;
atomic_inc(&cur_trans->use_count);
break;
}
}
spin_unlock(&root->fs_info->trans_lock);
if (!cur_trans)
goto out; /* nothing committing|committed */
}
wait_for_commit(root, cur_trans);
put_transaction(cur_trans);
out:
return ret;
}
void btrfs_throttle(struct btrfs_root *root)
{
if (!atomic_read(&root->fs_info->open_ioctl_trans))
wait_current_trans(root);
}
static int should_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int ret;
ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
return ret ? 1 : 0;
}
int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_transaction *cur_trans = trans->transaction;
int updates;
int err;
smp_mb();
if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
return 1;
updates = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
if (updates) {
err = btrfs_run_delayed_refs(trans, root, updates);
if (err) /* Error code will also eval true */
return err;
}
return should_end_transaction(trans, root);
}
static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int throttle)
{
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_fs_info *info = root->fs_info;
int count = 0;
int lock = (trans->type != TRANS_JOIN_NOLOCK);
int err = 0;
if (--trans->use_count) {
trans->block_rsv = trans->orig_rsv;
return 0;
}
/*
* do the qgroup accounting as early as possible
*/
err = btrfs_delayed_refs_qgroup_accounting(trans, info);
btrfs_trans_release_metadata(trans, root);
trans->block_rsv = NULL;
if (trans->qgroup_reserved) {
/*
* the same root has to be passed here between start_transaction
* and end_transaction. Subvolume quota depends on this.
*/
btrfs_qgroup_free(trans->root, trans->qgroup_reserved);
trans->qgroup_reserved = 0;
}
if (!list_empty(&trans->new_bgs))
btrfs_create_pending_block_groups(trans, root);
while (count < 1) {
unsigned long cur = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
if (cur &&
trans->transaction->delayed_refs.num_heads_ready > 64) {
trans->delayed_ref_updates = 0;
btrfs_run_delayed_refs(trans, root, cur);
} else {
break;
}
count++;
}
btrfs_trans_release_metadata(trans, root);
trans->block_rsv = NULL;
if (!list_empty(&trans->new_bgs))
btrfs_create_pending_block_groups(trans, root);
if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
should_end_transaction(trans, root)) {
trans->transaction->blocked = 1;
smp_wmb();
}
if (lock && cur_trans->blocked && !cur_trans->in_commit) {
if (throttle) {
/*
* We may race with somebody else here so end up having
* to call end_transaction on ourselves again, so inc
* our use_count.
*/
trans->use_count++;
return btrfs_commit_transaction(trans, root);
} else {
wake_up_process(info->transaction_kthread);
}
}
if (trans->type < TRANS_JOIN_NOLOCK)
sb_end_intwrite(root->fs_info->sb);
WARN_ON(cur_trans != info->running_transaction);
WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
atomic_dec(&cur_trans->num_writers);
smp_mb();
if (waitqueue_active(&cur_trans->writer_wait))
wake_up(&cur_trans->writer_wait);
put_transaction(cur_trans);
if (current->journal_info == trans)
current->journal_info = NULL;
if (throttle)
btrfs_run_delayed_iputs(root);
if (trans->aborted ||
test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
err = -EIO;
assert_qgroups_uptodate(trans);
kmem_cache_free(btrfs_trans_handle_cachep, trans);
return err;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return __btrfs_end_transaction(trans, root, 0);
}
int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return __btrfs_end_transaction(trans, root, 1);
}
int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
return __btrfs_end_transaction(trans, root, 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_root *root,
struct extent_io_tree *dirty_pages, int mark)
{
int err = 0;
int werr = 0;
struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
struct extent_state *cached_state = NULL;
u64 start = 0;
u64 end;
struct blk_plug plug;
blk_start_plug(&plug);
while (!find_first_extent_bit(dirty_pages, start, &start, &end,
mark, &cached_state)) {
convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
mark, &cached_state, GFP_NOFS);
cached_state = NULL;
err = filemap_fdatawrite_range(mapping, start, end);
if (err)
werr = err;
cond_resched();
start = end + 1;
}
if (err)
werr = err;
blk_finish_plug(&plug);
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
*/
int btrfs_wait_marked_extents(struct btrfs_root *root,
struct extent_io_tree *dirty_pages, int mark)
{
int err = 0;
int werr = 0;
struct address_space *mapping = root->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)) {
clear_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT,
0, 0, &cached_state, GFP_NOFS);
err = filemap_fdatawait_range(mapping, start, end);
if (err)
werr = err;
cond_resched();
start = end + 1;
}
if (err)
werr = err;
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
*/
int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
struct extent_io_tree *dirty_pages, int mark)
{
int ret;
int ret2;
ret = btrfs_write_marked_extents(root, dirty_pages, mark);
ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
if (ret)
return ret;
if (ret2)
return ret2;
return 0;
}
int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
if (!trans || !trans->transaction) {
struct inode *btree_inode;
btree_inode = root->fs_info->btree_inode;
return filemap_write_and_wait(btree_inode->i_mapping);
}
return btrfs_write_and_wait_marked_extents(root,
&trans->transaction->dirty_pages,
EXTENT_DIRTY);
}
/*
* 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_root *tree_root = root->fs_info->tree_root;
old_root_used = btrfs_root_used(&root->root_item);
btrfs_write_dirty_block_groups(trans, root);
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);
ret = btrfs_write_dirty_block_groups(trans, root);
if (ret)
return ret;
}
if (root != root->fs_info->extent_root)
switch_commit_root(root);
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_root *root)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct list_head *next;
struct extent_buffer *eb;
int ret;
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
if (ret)
return ret;
eb = btrfs_lock_root_node(fs_info->tree_root);
ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
0, &eb);
btrfs_tree_unlock(eb);
free_extent_buffer(eb);
if (ret)
return ret;
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
if (ret)
return ret;
ret = btrfs_run_dev_stats(trans, root->fs_info);
WARN_ON(ret);
ret = btrfs_run_dev_replace(trans, root->fs_info);
WARN_ON(ret);
ret = btrfs_run_qgroups(trans, root->fs_info);
BUG_ON(ret);
/* run_qgroups might have added some more refs */
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
while (!list_empty(&fs_info->dirty_cowonly_roots)) {
next = fs_info->dirty_cowonly_roots.next;
list_del_init(next);
root = list_entry(next, struct btrfs_root, dirty_list);
ret = update_cowonly_root(trans, root);
if (ret)
return ret;
}
down_write(&fs_info->extent_commit_sem);
switch_commit_root(fs_info->extent_root);
up_write(&fs_info->extent_commit_sem);
btrfs_after_dev_replace_commit(fs_info);
return 0;
}
/*
* 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
*/
int btrfs_add_dead_root(struct btrfs_root *root)
{
spin_lock(&root->fs_info->trans_lock);
list_add_tail(&root->root_list, &root->fs_info->dead_roots);
spin_unlock(&root->fs_info->trans_lock);
return 0;
}
/*
* update all the cowonly tree roots on disk
*/
static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
struct btrfs_root *gang[8];
struct btrfs_fs_info *fs_info = root->fs_info;
int i;
int ret;
int err = 0;
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++) {
root = gang[i];
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);
btrfs_update_reloc_root(trans, root);
btrfs_orphan_commit_root(trans, root);
btrfs_save_ino_cache(root, trans);
/* see comments in should_cow_block() */
root->force_cow = 0;
smp_wmb();
if (root->commit_root != root->node) {
mutex_lock(&root->fs_commit_mutex);
switch_commit_root(root);
btrfs_unpin_free_ino(root);
mutex_unlock(&root->fs_commit_mutex);
btrfs_set_root_node(&root->root_item,
root->node);
}
err = btrfs_update_root(trans, fs_info->tree_root,
&root->root_key,
&root->root_item);
spin_lock(&fs_info->fs_roots_radix_lock);
if (err)
break;
}
}
spin_unlock(&fs_info->fs_roots_radix_lock);
return err;
}
/*
* 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 (xchg(&root->defrag_running, 1))
return 0;
while (1) {
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
ret = btrfs_defrag_leaves(trans, root);
btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(info->tree_root);
cond_resched();
if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
break;
if (btrfs_defrag_cancelled(root->fs_info)) {
printk(KERN_DEBUG "btrfs: defrag_root cancelled\n");
ret = -EAGAIN;
break;
}
}
root->defrag_running = 0;
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_fs_info *fs_info,
struct btrfs_pending_snapshot *pending)
{
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;
struct btrfs_path *path;
struct btrfs_dir_item *dir_item;
struct dentry *dentry;
struct extent_buffer *tmp;
struct extent_buffer *old;
struct timespec cur_time = CURRENT_TIME;
int ret = 0;
u64 to_reserve = 0;
u64 index = 0;
u64 objectid;
u64 root_flags;
uuid_le new_uuid;
path = btrfs_alloc_path();
if (!path) {
pending->error = -ENOMEM;
return 0;
}
new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
if (!new_root_item) {
pending->error = -ENOMEM;
goto root_item_alloc_fail;
}
pending->error = btrfs_find_free_objectid(tree_root, &objectid);
if (pending->error)
goto no_free_objectid;
btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
if (to_reserve > 0) {
pending->error = btrfs_block_rsv_add(root,
&pending->block_rsv,
to_reserve,
BTRFS_RESERVE_NO_FLUSH);
if (pending->error)
goto no_free_objectid;
}
pending->error = btrfs_qgroup_inherit(trans, fs_info,
root->root_key.objectid,
objectid, pending->inherit);
if (pending->error)
goto no_free_objectid;
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;
dentry = pending->dentry;
parent_inode = pending->dir;
parent_root = BTRFS_I(parent_inode)->root;
record_root_in_trans(trans, parent_root);
/*
* insert the directory item
*/
ret = btrfs_set_inode_index(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(parent_inode),
dentry->d_name.name,
dentry->d_name.len, 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, root, 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, root);
if (ret) { /* Transaction aborted */
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
record_root_in_trans(trans, root);
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);
uuid_le_gen(&new_uuid);
memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
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);
}
new_root_item->otime.sec = cpu_to_le64(cur_time.tv_sec);
new_root_item->otime.nsec = cpu_to_le32(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);
if (ret) {
btrfs_tree_unlock(old);
free_extent_buffer(old);
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
btrfs_set_lock_blocking(old);
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, root, ret);
goto fail;
}
/* see comments in should_cow_block() */
root->force_cow = 1;
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, root, ret);
goto fail;
}
/*
* insert root back/forward references
*/
ret = btrfs_add_root_ref(trans, tree_root, objectid,
parent_root->root_key.objectid,
btrfs_ino(parent_inode), index,
dentry->d_name.name, dentry->d_name.len);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
key.offset = (u64)-1;
pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
if (IS_ERR(pending->snap)) {
ret = PTR_ERR(pending->snap);
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
ret = btrfs_reloc_post_snapshot(trans, pending);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
goto fail;
}
ret = btrfs_insert_dir_item(trans, parent_root,
dentry->d_name.name, dentry->d_name.len,
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, root, ret);
goto fail;
}
btrfs_i_size_write(parent_inode, parent_inode->i_size +
dentry->d_name.len * 2);
parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
if (ret)
btrfs_abort_transaction(trans, root, ret);
fail:
pending->error = ret;
dir_item_existed:
trans->block_rsv = rsv;
trans->bytes_reserved = 0;
no_free_objectid:
kfree(new_root_item);
root_item_alloc_fail:
btrfs_free_path(path);
return ret;
}
/*
* create all the snapshots we've scheduled for creation
*/
static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info)
{
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, fs_info, pending);
if (ret)
break;
}
return ret;
}
static void update_super_roots(struct btrfs_root *root)
{
struct btrfs_root_item *root_item;
struct btrfs_super_block *super;
super = root->fs_info->super_copy;
root_item = &root->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 = &root->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(root, SPACE_CACHE))
super->cache_generation = root_item->generation;
}
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
int ret = 0;
spin_lock(&info->trans_lock);
if (info->running_transaction)
ret = info->running_transaction->in_commit;
spin_unlock(&info->trans_lock);
return ret;
}
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
int ret = 0;
spin_lock(&info->trans_lock);
if (info->running_transaction)
ret = info->running_transaction->blocked;
spin_unlock(&info->trans_lock);
return ret;
}
/*
* wait for the current transaction commit to start and block subsequent
* transaction joins
*/
static void wait_current_trans_commit_start(struct btrfs_root *root,
struct btrfs_transaction *trans)
{
wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
}
/*
* wait for the current transaction to start and then become unblocked.
* caller holds ref.
*/
static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
struct btrfs_transaction *trans)
{
wait_event(root->fs_info->transaction_wait,
trans->commit_done || (trans->in_commit && !trans->blocked));
}
/*
* commit transactions asynchronously. once btrfs_commit_transaction_async
* returns, any subsequent transaction will not be allowed to join.
*/
struct btrfs_async_commit {
struct btrfs_trans_handle *newtrans;
struct btrfs_root *root;
struct work_struct work;
};
static void do_async_commit(struct work_struct *work)
{
struct btrfs_async_commit *ac =
container_of(work, struct btrfs_async_commit, work);
/*
* We've got freeze protection passed with the transaction.
* Tell lockdep about it.
*/
if (ac->newtrans->type < TRANS_JOIN_NOLOCK)
rwsem_acquire_read(
&ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
0, 1, _THIS_IP_);
current->journal_info = ac->newtrans;
btrfs_commit_transaction(ac->newtrans, ac->root);
kfree(ac);
}
int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
int wait_for_unblock)
{
struct btrfs_async_commit *ac;
struct btrfs_transaction *cur_trans;
ac = kmalloc(sizeof(*ac), GFP_NOFS);
if (!ac)
return -ENOMEM;
INIT_WORK(&ac->work, do_async_commit);
ac->root = root;
ac->newtrans = btrfs_join_transaction(root);
if (IS_ERR(ac->newtrans)) {
int err = PTR_ERR(ac->newtrans);
kfree(ac);
return err;
}
/* take transaction reference */
cur_trans = trans->transaction;
atomic_inc(&cur_trans->use_count);
btrfs_end_transaction(trans, root);
/*
* Tell lockdep we've released the freeze rwsem, since the
* async commit thread will be the one to unlock it.
*/
if (trans->type < TRANS_JOIN_NOLOCK)
rwsem_release(
&root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
1, _THIS_IP_);
schedule_work(&ac->work);
/* wait for transaction to start and unblock */
if (wait_for_unblock)
wait_current_trans_commit_start_and_unblock(root, cur_trans);
else
wait_current_trans_commit_start(root, cur_trans);
if (current->journal_info == trans)
current->journal_info = NULL;
put_transaction(cur_trans);
return 0;
}
static void cleanup_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, int err)
{
struct btrfs_transaction *cur_trans = trans->transaction;
DEFINE_WAIT(wait);
WARN_ON(trans->use_count > 1);
btrfs_abort_transaction(trans, root, err);
spin_lock(&root->fs_info->trans_lock);
if (list_empty(&cur_trans->list)) {
spin_unlock(&root->fs_info->trans_lock);
btrfs_end_transaction(trans, root);
return;
}
list_del_init(&cur_trans->list);
if (cur_trans == root->fs_info->running_transaction) {
root->fs_info->trans_no_join = 1;
spin_unlock(&root->fs_info->trans_lock);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
spin_lock(&root->fs_info->trans_lock);
root->fs_info->running_transaction = NULL;
}
spin_unlock(&root->fs_info->trans_lock);
btrfs_cleanup_one_transaction(trans->transaction, root);
put_transaction(cur_trans);
put_transaction(cur_trans);
trace_btrfs_transaction_commit(root);
btrfs_scrub_continue(root);
if (current->journal_info == trans)
current->journal_info = NULL;
kmem_cache_free(btrfs_trans_handle_cachep, trans);
spin_lock(&root->fs_info->trans_lock);
root->fs_info->trans_no_join = 0;
spin_unlock(&root->fs_info->trans_lock);
}
static int btrfs_flush_all_pending_stuffs(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
int snap_pending = 0;
int ret;
if (!flush_on_commit) {
spin_lock(&root->fs_info->trans_lock);
if (!list_empty(&trans->transaction->pending_snapshots))
snap_pending = 1;
spin_unlock(&root->fs_info->trans_lock);
}
if (flush_on_commit || snap_pending) {
ret = btrfs_start_delalloc_inodes(root, 1);
if (ret)
return ret;
btrfs_wait_ordered_extents(root, 1);
}
ret = btrfs_run_delayed_items(trans, root);
if (ret)
return ret;
/*
* running the delayed items may have added new refs. account
* them now so that they hinder processing of more delayed refs
* as little as possible.
*/
btrfs_delayed_refs_qgroup_accounting(trans, root->fs_info);
/*
* rename don't use btrfs_join_transaction, so, once we
* set the transaction to blocked above, we aren't going
* to get any new ordered operations. We can safely run
* it here and no for sure that nothing new will be added
* to the list
*/
ret = btrfs_run_ordered_operations(trans, root, 1);
return ret;
}
/*
* btrfs_transaction state sequence:
* in_commit = 0, blocked = 0 (initial)
* in_commit = 1, blocked = 1
* blocked = 0
* commit_done = 1
*/
int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root)
{
unsigned long joined = 0;
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_transaction *prev_trans = NULL;
DEFINE_WAIT(wait);
int ret;
int should_grow = 0;
unsigned long now = get_seconds();
ret = btrfs_run_ordered_operations(trans, root, 0);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
btrfs_end_transaction(trans, root);
return ret;
}
/* Stop the commit early if ->aborted is set */
if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
btrfs_end_transaction(trans, root);
return ret;
}
/* make a pass through all the delayed refs we have so far
* any runnings procs may add more while we are here
*/
ret = btrfs_run_delayed_refs(trans, root, 0);
if (ret) {
btrfs_end_transaction(trans, root);
return ret;
}
btrfs_trans_release_metadata(trans, root);
trans->block_rsv = NULL;
if (trans->qgroup_reserved) {
btrfs_qgroup_free(root, trans->qgroup_reserved);
trans->qgroup_reserved = 0;
}
cur_trans = trans->transaction;
/*
* set the flushing flag so procs in this transaction have to
* start sending their work down.
*/
cur_trans->delayed_refs.flushing = 1;
if (!list_empty(&trans->new_bgs))
btrfs_create_pending_block_groups(trans, root);
ret = btrfs_run_delayed_refs(trans, root, 0);
if (ret) {
btrfs_end_transaction(trans, root);
return ret;
}
spin_lock(&cur_trans->commit_lock);
if (cur_trans->in_commit) {
spin_unlock(&cur_trans->commit_lock);
atomic_inc(&cur_trans->use_count);
ret = btrfs_end_transaction(trans, root);
wait_for_commit(root, cur_trans);
put_transaction(cur_trans);
return ret;
}
trans->transaction->in_commit = 1;
trans->transaction->blocked = 1;
spin_unlock(&cur_trans->commit_lock);
wake_up(&root->fs_info->transaction_blocked_wait);
spin_lock(&root->fs_info->trans_lock);
if (cur_trans->list.prev != &root->fs_info->trans_list) {
prev_trans = list_entry(cur_trans->list.prev,
struct btrfs_transaction, list);
if (!prev_trans->commit_done) {
atomic_inc(&prev_trans->use_count);
spin_unlock(&root->fs_info->trans_lock);
wait_for_commit(root, prev_trans);
put_transaction(prev_trans);
} else {
spin_unlock(&root->fs_info->trans_lock);
}
} else {
spin_unlock(&root->fs_info->trans_lock);
}
if (!btrfs_test_opt(root, SSD) &&
(now < cur_trans->start_time || now - cur_trans->start_time < 1))
should_grow = 1;
do {
joined = cur_trans->num_joined;
WARN_ON(cur_trans != trans->transaction);
ret = btrfs_flush_all_pending_stuffs(trans, root);
if (ret)
goto cleanup_transaction;
prepare_to_wait(&cur_trans->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (atomic_read(&cur_trans->num_writers) > 1)
schedule_timeout(MAX_SCHEDULE_TIMEOUT);
else if (should_grow)
schedule_timeout(1);
finish_wait(&cur_trans->writer_wait, &wait);
} while (atomic_read(&cur_trans->num_writers) > 1 ||
(should_grow && cur_trans->num_joined != joined));
ret = btrfs_flush_all_pending_stuffs(trans, root);
if (ret)
goto cleanup_transaction;
/*
* 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
* no_join so make sure to wait for num_writers to == 1 again.
*/
spin_lock(&root->fs_info->trans_lock);
root->fs_info->trans_no_join = 1;
spin_unlock(&root->fs_info->trans_lock);
wait_event(cur_trans->writer_wait,
atomic_read(&cur_trans->num_writers) == 1);
/* ->aborted might be set after the previous check, so check it */
if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
goto cleanup_transaction;
}
/*
* 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(&root->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, root->fs_info);
if (ret) {
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
/*
* 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, root);
if (ret) {
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
if (ret) {
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
/*
* make sure none of the code above managed to slip in a
* delayed item
*/
btrfs_assert_delayed_root_empty(root);
WARN_ON(cur_trans != trans->transaction);
btrfs_scrub_pause(root);
/* btrfs_commit_tree_roots is responsible for getting the
* various roots consistent with each other. Every pointer
* in the tree of tree roots has to point to the most up to date
* root for every subvolume and other tree. So, we have to keep
* the tree logging code from jumping in and changing any
* of the trees.
*
* At this point in the commit, there can't be any tree-log
* writers, but a little lower down we drop the trans mutex
* and let new people in. By holding the tree_log_mutex
* from now until after the super is written, we avoid races
* with the tree-log code.
*/
mutex_lock(&root->fs_info->tree_log_mutex);
ret = commit_fs_roots(trans, root);
if (ret) {
mutex_unlock(&root->fs_info->tree_log_mutex);
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
/* 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, root->fs_info);
ret = commit_cowonly_roots(trans, root);
if (ret) {
mutex_unlock(&root->fs_info->tree_log_mutex);
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
/*
* The tasks which save the space cache and inode cache may also
* update ->aborted, check it.
*/
if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
ret = cur_trans->aborted;
mutex_unlock(&root->fs_info->tree_log_mutex);
mutex_unlock(&root->fs_info->reloc_mutex);
goto cleanup_transaction;
}
btrfs_prepare_extent_commit(trans, root);
cur_trans = root->fs_info->running_transaction;
btrfs_set_root_node(&root->fs_info->tree_root->root_item,
root->fs_info->tree_root->node);
switch_commit_root(root->fs_info->tree_root);
btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
root->fs_info->chunk_root->node);
switch_commit_root(root->fs_info->chunk_root);
assert_qgroups_uptodate(trans);
update_super_roots(root);
if (!root->fs_info->log_root_recovering) {
btrfs_set_super_log_root(root->fs_info->super_copy, 0);
btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
}
memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
sizeof(*root->fs_info->super_copy));
trans->transaction->blocked = 0;
spin_lock(&root->fs_info->trans_lock);
root->fs_info->running_transaction = NULL;
root->fs_info->trans_no_join = 0;
spin_unlock(&root->fs_info->trans_lock);
mutex_unlock(&root->fs_info->reloc_mutex);
wake_up(&root->fs_info->transaction_wait);
ret = btrfs_write_and_wait_transaction(trans, root);
if (ret) {
btrfs_error(root->fs_info, ret,
"Error while writing out transaction");
mutex_unlock(&root->fs_info->tree_log_mutex);
goto cleanup_transaction;
}
ret = write_ctree_super(trans, root, 0);
if (ret) {
mutex_unlock(&root->fs_info->tree_log_mutex);
goto cleanup_transaction;
}
/*
* the super is written, we can safely allow the tree-loggers
* to go about their business
*/
mutex_unlock(&root->fs_info->tree_log_mutex);
btrfs_finish_extent_commit(trans, root);
cur_trans->commit_done = 1;
root->fs_info->last_trans_committed = cur_trans->transid;
wake_up(&cur_trans->commit_wait);
spin_lock(&root->fs_info->trans_lock);
list_del_init(&cur_trans->list);
spin_unlock(&root->fs_info->trans_lock);
put_transaction(cur_trans);
put_transaction(cur_trans);
if (trans->type < TRANS_JOIN_NOLOCK)
sb_end_intwrite(root->fs_info->sb);
trace_btrfs_transaction_commit(root);
btrfs_scrub_continue(root);
if (current->journal_info == trans)
current->journal_info = NULL;
kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (current != root->fs_info->transaction_kthread)
btrfs_run_delayed_iputs(root);
return ret;
cleanup_transaction:
btrfs_trans_release_metadata(trans, root);
trans->block_rsv = NULL;
if (trans->qgroup_reserved) {
btrfs_qgroup_free(root, trans->qgroup_reserved);
trans->qgroup_reserved = 0;
}
btrfs_warn(root->fs_info, "Skipping commit of aborted transaction.");
if (current->journal_info == trans)
current->journal_info = NULL;
cleanup_transaction(trans, root, ret);
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_root *root)
{
int ret;
struct btrfs_fs_info *fs_info = root->fs_info;
if (fs_info->sb->s_flags & MS_RDONLY) {
pr_debug("btrfs: cleaner called for RO fs!\n");
return 0;
}
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(&root->root_list);
spin_unlock(&fs_info->trans_lock);
pr_debug("btrfs: cleaner removing %llu\n",
(unsigned long long)root->objectid);
btrfs_kill_all_delayed_nodes(root);
if (btrfs_header_backref_rev(root->node) <
BTRFS_MIXED_BACKREF_REV)
ret = btrfs_drop_snapshot(root, NULL, 0, 0);
else
ret = btrfs_drop_snapshot(root, NULL, 1, 0);
/*
* If we encounter a transaction abort during snapshot cleaning, we
* don't want to crash here
*/
BUG_ON(ret < 0 && ret != -EAGAIN && ret != -EROFS);
return 1;
}
