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path: root/fs/btrfs/transaction.c
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Diffstat (limited to 'fs/btrfs/transaction.c')
-rw-r--r--fs/btrfs/transaction.c377
1 files changed, 243 insertions, 134 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index dc80f7156923..51dcec86757f 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -35,6 +35,7 @@ static noinline 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));
memset(transaction, 0, sizeof(*transaction));
kmem_cache_free(btrfs_transaction_cachep, transaction);
}
@@ -49,46 +50,72 @@ static noinline void switch_commit_root(struct btrfs_root *root)
/*
* either allocate a new transaction or hop into the existing one
*/
-static noinline int join_transaction(struct btrfs_root *root)
+static noinline int join_transaction(struct btrfs_root *root, int nofail)
{
struct btrfs_transaction *cur_trans;
+
+ spin_lock(&root->fs_info->trans_lock);
+ if (root->fs_info->trans_no_join) {
+ if (!nofail) {
+ spin_unlock(&root->fs_info->trans_lock);
+ return -EBUSY;
+ }
+ }
+
cur_trans = root->fs_info->running_transaction;
- if (!cur_trans) {
- cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
- GFP_NOFS);
- if (!cur_trans)
- return -ENOMEM;
- root->fs_info->generation++;
- atomic_set(&cur_trans->num_writers, 1);
- cur_trans->num_joined = 0;
- cur_trans->transid = root->fs_info->generation;
- init_waitqueue_head(&cur_trans->writer_wait);
- init_waitqueue_head(&cur_trans->commit_wait);
- cur_trans->in_commit = 0;
- cur_trans->blocked = 0;
- atomic_set(&cur_trans->use_count, 1);
- 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;
- spin_lock_init(&cur_trans->delayed_refs.lock);
-
- INIT_LIST_HEAD(&cur_trans->pending_snapshots);
- list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
- extent_io_tree_init(&cur_trans->dirty_pages,
- root->fs_info->btree_inode->i_mapping);
- spin_lock(&root->fs_info->new_trans_lock);
- root->fs_info->running_transaction = cur_trans;
- spin_unlock(&root->fs_info->new_trans_lock);
- } else {
+ if (cur_trans) {
+ atomic_inc(&cur_trans->use_count);
+ atomic_inc(&cur_trans->num_writers);
+ cur_trans->num_joined++;
+ spin_unlock(&root->fs_info->trans_lock);
+ return 0;
+ }
+ spin_unlock(&root->fs_info->trans_lock);
+
+ cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
+ if (!cur_trans)
+ return -ENOMEM;
+ spin_lock(&root->fs_info->trans_lock);
+ if (root->fs_info->running_transaction) {
+ kmem_cache_free(btrfs_transaction_cachep, cur_trans);
+ cur_trans = root->fs_info->running_transaction;
+ atomic_inc(&cur_trans->use_count);
atomic_inc(&cur_trans->num_writers);
cur_trans->num_joined++;
+ spin_unlock(&root->fs_info->trans_lock);
+ return 0;
}
+ 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;
+ spin_lock_init(&cur_trans->commit_lock);
+ spin_lock_init(&cur_trans->delayed_refs.lock);
+
+ INIT_LIST_HEAD(&cur_trans->pending_snapshots);
+ list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
+ extent_io_tree_init(&cur_trans->dirty_pages,
+ root->fs_info->btree_inode->i_mapping);
+ root->fs_info->generation++;
+ cur_trans->transid = root->fs_info->generation;
+ root->fs_info->running_transaction = cur_trans;
+ spin_unlock(&root->fs_info->trans_lock);
return 0;
}
@@ -99,36 +126,82 @@ static noinline int join_transaction(struct btrfs_root *root)
* to make sure the old root from before we joined the transaction is deleted
* when the transaction commits
*/
-static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
- struct btrfs_root *root)
+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;
- mutex_lock(&root->fs_info->trans_mutex);
- if (root->last_trans == trans->transid) {
- mutex_unlock(&root->fs_info->trans_mutex);
+ /*
+ * 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->trans_mutex);
+ mutex_unlock(&root->fs_info->reloc_mutex);
+
return 0;
}
@@ -140,21 +213,23 @@ 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) {
DEFINE_WAIT(wait);
atomic_inc(&cur_trans->use_count);
+ spin_unlock(&root->fs_info->trans_lock);
while (1) {
prepare_to_wait(&root->fs_info->transaction_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (!cur_trans->blocked)
break;
- mutex_unlock(&root->fs_info->trans_mutex);
schedule();
- mutex_lock(&root->fs_info->trans_mutex);
}
finish_wait(&root->fs_info->transaction_wait, &wait);
put_transaction(cur_trans);
+ } else {
+ spin_unlock(&root->fs_info->trans_lock);
}
}
@@ -167,10 +242,16 @@ enum btrfs_trans_type {
static int may_wait_transaction(struct btrfs_root *root, int type)
{
- if (!root->fs_info->log_root_recovering &&
- ((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
- type == TRANS_USERSPACE))
+ 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;
}
@@ -184,36 +265,44 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
return ERR_PTR(-EROFS);
+
+ if (current->journal_info) {
+ WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
+ h = current->journal_info;
+ h->use_count++;
+ h->orig_rsv = h->block_rsv;
+ h->block_rsv = NULL;
+ goto got_it;
+ }
again:
h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
if (!h)
return ERR_PTR(-ENOMEM);
- if (type != TRANS_JOIN_NOLOCK)
- mutex_lock(&root->fs_info->trans_mutex);
if (may_wait_transaction(root, type))
wait_current_trans(root);
- ret = join_transaction(root);
+ do {
+ ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
+ if (ret == -EBUSY)
+ wait_current_trans(root);
+ } while (ret == -EBUSY);
+
if (ret < 0) {
kmem_cache_free(btrfs_trans_handle_cachep, h);
- if (type != TRANS_JOIN_NOLOCK)
- mutex_unlock(&root->fs_info->trans_mutex);
return ERR_PTR(ret);
}
cur_trans = root->fs_info->running_transaction;
- atomic_inc(&cur_trans->use_count);
- if (type != TRANS_JOIN_NOLOCK)
- mutex_unlock(&root->fs_info->trans_mutex);
h->transid = cur_trans->transid;
h->transaction = cur_trans;
h->blocks_used = 0;
- h->block_group = 0;
h->bytes_reserved = 0;
h->delayed_ref_updates = 0;
+ h->use_count = 1;
h->block_rsv = NULL;
+ h->orig_rsv = NULL;
smp_mb();
if (cur_trans->blocked && may_wait_transaction(root, type)) {
@@ -241,11 +330,8 @@ again:
}
}
- if (type != TRANS_JOIN_NOLOCK)
- mutex_lock(&root->fs_info->trans_mutex);
- record_root_in_trans(h, root);
- if (type != TRANS_JOIN_NOLOCK)
- mutex_unlock(&root->fs_info->trans_mutex);
+got_it:
+ btrfs_record_root_in_trans(h, root);
if (!current->journal_info && type != TRANS_USERSPACE)
current->journal_info = h;
@@ -257,22 +343,19 @@ struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
{
return start_transaction(root, num_items, TRANS_START);
}
-struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
- int num_blocks)
+struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN);
}
-struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root,
- int num_blocks)
+struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
{
return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
}
-struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
- int num_blocks)
+struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
{
- return start_transaction(r, 0, TRANS_USERSPACE);
+ return start_transaction(root, 0, TRANS_USERSPACE);
}
/* wait for a transaction commit to be fully complete */
@@ -280,17 +363,13 @@ static noinline int wait_for_commit(struct btrfs_root *root,
struct btrfs_transaction *commit)
{
DEFINE_WAIT(wait);
- mutex_lock(&root->fs_info->trans_mutex);
while (!commit->commit_done) {
prepare_to_wait(&commit->commit_wait, &wait,
TASK_UNINTERRUPTIBLE);
if (commit->commit_done)
break;
- mutex_unlock(&root->fs_info->trans_mutex);
schedule();
- mutex_lock(&root->fs_info->trans_mutex);
}
- mutex_unlock(&root->fs_info->trans_mutex);
finish_wait(&commit->commit_wait, &wait);
return 0;
}
@@ -300,59 +379,56 @@ int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
struct btrfs_transaction *cur_trans = NULL, *t;
int ret;
- mutex_lock(&root->fs_info->trans_mutex);
-
ret = 0;
if (transid) {
if (transid <= root->fs_info->last_trans_committed)
- goto out_unlock;
+ goto out;
/* 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);
break;
}
if (t->transid > transid)
break;
}
+ spin_unlock(&root->fs_info->trans_lock);
ret = -EINVAL;
if (!cur_trans)
- goto out_unlock; /* bad transid */
+ goto out; /* bad transid */
} 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)
- goto out_unlock;
+ break;
cur_trans = t;
+ atomic_inc(&cur_trans->use_count);
break;
}
}
+ spin_unlock(&root->fs_info->trans_lock);
if (!cur_trans)
- goto out_unlock; /* nothing committing|committed */
+ goto out; /* nothing committing|committed */
}
- atomic_inc(&cur_trans->use_count);
- mutex_unlock(&root->fs_info->trans_mutex);
-
wait_for_commit(root, cur_trans);
- mutex_lock(&root->fs_info->trans_mutex);
put_transaction(cur_trans);
ret = 0;
-out_unlock:
- mutex_unlock(&root->fs_info->trans_mutex);
+out:
return ret;
}
void btrfs_throttle(struct btrfs_root *root)
{
- mutex_lock(&root->fs_info->trans_mutex);
- if (!root->fs_info->open_ioctl_trans)
+ if (!atomic_read(&root->fs_info->open_ioctl_trans))
wait_current_trans(root);
- mutex_unlock(&root->fs_info->trans_mutex);
}
static int should_end_transaction(struct btrfs_trans_handle *trans,
@@ -370,6 +446,7 @@ int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_transaction *cur_trans = trans->transaction;
int updates;
+ smp_mb();
if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
return 1;
@@ -388,6 +465,11 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *info = root->fs_info;
int count = 0;
+ if (--trans->use_count) {
+ trans->block_rsv = trans->orig_rsv;
+ return 0;
+ }
+
while (count < 4) {
unsigned long cur = trans->delayed_ref_updates;
trans->delayed_ref_updates = 0;
@@ -410,9 +492,11 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
btrfs_trans_release_metadata(trans, root);
- if (lock && !root->fs_info->open_ioctl_trans &&
- should_end_transaction(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)
@@ -703,9 +787,9 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
*/
int btrfs_add_dead_root(struct btrfs_root *root)
{
- mutex_lock(&root->fs_info->trans_mutex);
+ spin_lock(&root->fs_info->trans_lock);
list_add(&root->root_list, &root->fs_info->dead_roots);
- mutex_unlock(&root->fs_info->trans_mutex);
+ spin_unlock(&root->fs_info->trans_lock);
return 0;
}
@@ -721,6 +805,7 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
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,
@@ -733,6 +818,7 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
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);
@@ -753,10 +839,12 @@ static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
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;
}
@@ -786,7 +874,7 @@ int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
btrfs_btree_balance_dirty(info->tree_root, nr);
cond_resched();
- if (root->fs_info->closing || ret != -EAGAIN)
+ if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
break;
}
root->defrag_running = 0;
@@ -869,6 +957,15 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
ret = btrfs_update_inode(trans, parent_root, parent_inode);
BUG_ON(ret);
+ /*
+ * 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);
+ BUG_ON(ret);
+
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));
@@ -930,14 +1027,6 @@ static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
int ret;
list_for_each_entry(pending, head, list) {
- /*
- * We must deal with the delayed items before creating
- * snapshots, or we will create a snapthot with inconsistent
- * information.
- */
- ret = btrfs_run_delayed_items(trans, fs_info->fs_root);
- BUG_ON(ret);
-
ret = create_pending_snapshot(trans, fs_info, pending);
BUG_ON(ret);
}
@@ -967,20 +1056,20 @@ static void update_super_roots(struct btrfs_root *root)
int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
{
int ret = 0;
- spin_lock(&info->new_trans_lock);
+ spin_lock(&info->trans_lock);
if (info->running_transaction)
ret = info->running_transaction->in_commit;
- spin_unlock(&info->new_trans_lock);
+ spin_unlock(&info->trans_lock);
return ret;
}
int btrfs_transaction_blocked(struct btrfs_fs_info *info)
{
int ret = 0;
- spin_lock(&info->new_trans_lock);
+ spin_lock(&info->trans_lock);
if (info->running_transaction)
ret = info->running_transaction->blocked;
- spin_unlock(&info->new_trans_lock);
+ spin_unlock(&info->trans_lock);
return ret;
}
@@ -1004,9 +1093,7 @@ static void wait_current_trans_commit_start(struct btrfs_root *root,
&wait);
break;
}
- mutex_unlock(&root->fs_info->trans_mutex);
schedule();
- mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&root->fs_info->transaction_blocked_wait, &wait);
}
}
@@ -1032,9 +1119,7 @@ static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
&wait);
break;
}
- mutex_unlock(&root->fs_info->trans_mutex);
schedule();
- mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&root->fs_info->transaction_wait,
&wait);
}
@@ -1072,7 +1157,7 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
INIT_DELAYED_WORK(&ac->work, do_async_commit);
ac->root = root;
- ac->newtrans = btrfs_join_transaction(root, 0);
+ ac->newtrans = btrfs_join_transaction(root);
if (IS_ERR(ac->newtrans)) {
int err = PTR_ERR(ac->newtrans);
kfree(ac);
@@ -1080,23 +1165,22 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
}
/* take transaction reference */
- mutex_lock(&root->fs_info->trans_mutex);
cur_trans = trans->transaction;
atomic_inc(&cur_trans->use_count);
- mutex_unlock(&root->fs_info->trans_mutex);
btrfs_end_transaction(trans, root);
schedule_delayed_work(&ac->work, 0);
/* wait for transaction to start and unblock */
- mutex_lock(&root->fs_info->trans_mutex);
if (wait_for_unblock)
wait_current_trans_commit_start_and_unblock(root, cur_trans);
else
wait_current_trans_commit_start(root, cur_trans);
- put_transaction(cur_trans);
- mutex_unlock(&root->fs_info->trans_mutex);
+ if (current->journal_info == trans)
+ current->journal_info = NULL;
+
+ put_transaction(cur_trans);
return 0;
}
@@ -1139,38 +1223,41 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
ret = btrfs_run_delayed_refs(trans, root, 0);
BUG_ON(ret);
- mutex_lock(&root->fs_info->trans_mutex);
+ spin_lock(&cur_trans->commit_lock);
if (cur_trans->in_commit) {
+ spin_unlock(&cur_trans->commit_lock);
atomic_inc(&cur_trans->use_count);
- mutex_unlock(&root->fs_info->trans_mutex);
btrfs_end_transaction(trans, root);
ret = wait_for_commit(root, cur_trans);
BUG_ON(ret);
- mutex_lock(&root->fs_info->trans_mutex);
put_transaction(cur_trans);
- mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
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);
- mutex_unlock(&root->fs_info->trans_mutex);
+ spin_unlock(&root->fs_info->trans_lock);
wait_for_commit(root, prev_trans);
- mutex_lock(&root->fs_info->trans_mutex);
put_transaction(prev_trans);
+ } else {
+ spin_unlock(&root->fs_info->trans_lock);
}
+ } else {
+ spin_unlock(&root->fs_info->trans_lock);
}
if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
@@ -1178,12 +1265,12 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
do {
int snap_pending = 0;
+
joined = cur_trans->num_joined;
if (!list_empty(&trans->transaction->pending_snapshots))
snap_pending = 1;
WARN_ON(cur_trans != trans->transaction);
- mutex_unlock(&root->fs_info->trans_mutex);
if (flush_on_commit || snap_pending) {
btrfs_start_delalloc_inodes(root, 1);
@@ -1206,26 +1293,48 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
prepare_to_wait(&cur_trans->writer_wait, &wait,
TASK_UNINTERRUPTIBLE);
- smp_mb();
if (atomic_read(&cur_trans->num_writers) > 1)
schedule_timeout(MAX_SCHEDULE_TIMEOUT);
else if (should_grow)
schedule_timeout(1);
- mutex_lock(&root->fs_info->trans_mutex);
finish_wait(&cur_trans->writer_wait, &wait);
} while (atomic_read(&cur_trans->num_writers) > 1 ||
(should_grow && cur_trans->num_joined != joined));
- ret = create_pending_snapshots(trans, root->fs_info);
- BUG_ON(ret);
+ /*
+ * 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);
+
+ /*
+ * 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);
ret = btrfs_run_delayed_items(trans, root);
BUG_ON(ret);
+ ret = create_pending_snapshots(trans, root->fs_info);
+ BUG_ON(ret);
+
ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
BUG_ON(ret);
+ /*
+ * 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);
@@ -1258,9 +1367,6 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
btrfs_prepare_extent_commit(trans, root);
cur_trans = root->fs_info->running_transaction;
- spin_lock(&root->fs_info->new_trans_lock);
- root->fs_info->running_transaction = NULL;
- spin_unlock(&root->fs_info->new_trans_lock);
btrfs_set_root_node(&root->fs_info->tree_root->root_item,
root->fs_info->tree_root->node);
@@ -1281,10 +1387,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
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);
- mutex_unlock(&root->fs_info->trans_mutex);
ret = btrfs_write_and_wait_transaction(trans, root);
BUG_ON(ret);
write_ctree_super(trans, root, 0);
@@ -1297,22 +1407,21 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
btrfs_finish_extent_commit(trans, root);
- mutex_lock(&root->fs_info->trans_mutex);
-
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);
trace_btrfs_transaction_commit(root);
- mutex_unlock(&root->fs_info->trans_mutex);
-
btrfs_scrub_continue(root);
if (current->journal_info == trans)
@@ -1334,9 +1443,9 @@ int btrfs_clean_old_snapshots(struct btrfs_root *root)
LIST_HEAD(list);
struct btrfs_fs_info *fs_info = root->fs_info;
- mutex_lock(&fs_info->trans_mutex);
+ spin_lock(&fs_info->trans_lock);
list_splice_init(&fs_info->dead_roots, &list);
- mutex_unlock(&fs_info->trans_mutex);
+ spin_unlock(&fs_info->trans_lock);
while (!list_empty(&list)) {
root = list_entry(list.next, struct btrfs_root, root_list);