Btrfs: kill trans_mutex
We use trans_mutex for lots of things, here's a basic list
1) To serialize trans_handles joining the currently running transaction
2) To make sure that no new trans handles are started while we are committing
3) To protect the dead_roots list and the transaction lists
Really the serializing trans_handles joining is not too hard, and can really get
bogged down in acquiring a reference to the transaction. So replace the
trans_mutex with a trans_lock spinlock and use it to do the following
1) Protect fs_info->running_transaction. All trans handles have to do is check
this, and then take a reference of the transaction and keep on going.
2) Protect the fs_info->trans_list. This doesn't get used too much, basically
it just holds the current transactions, which will usually just be the currently
committing transaction and the currently running transaction at most.
3) Protect the dead roots list. This is only ever processed by splicing the
list so this is relatively simple.
4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using
the trans_mutex before, so this is a pretty straightforward change.
5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over
the entirety of the commit we need to have a way to block new people from
creating a new transaction while we're doing our work. So we set no_trans_join
and in join_transaction we test to see if that is set, and if it is we do a
wait_on_commit.
6) Make the transaction use count atomic so we don't need to take locks to
modify it when we're dropping references.
7) Add a commit_lock to the transaction to make sure multiple people trying to
commit the same transaction don't race and commit at the same time.
8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl
trans.
I have tested this with xfstests, but obviously it is a pretty hairy change so
lots of testing is greatly appreciated. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8f4b81d..522a39b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -919,7 +919,6 @@
* is required instead of the faster short fsync log commits
*/
u64 last_trans_log_full_commit;
- u64 open_ioctl_trans;
unsigned long mount_opt:20;
unsigned long compress_type:4;
u64 max_inline;
@@ -936,7 +935,6 @@
struct super_block *sb;
struct inode *btree_inode;
struct backing_dev_info bdi;
- struct mutex trans_mutex;
struct mutex tree_log_mutex;
struct mutex transaction_kthread_mutex;
struct mutex cleaner_mutex;
@@ -957,6 +955,7 @@
struct rw_semaphore subvol_sem;
struct srcu_struct subvol_srcu;
+ spinlock_t trans_lock;
struct list_head trans_list;
struct list_head hashers;
struct list_head dead_roots;
@@ -969,6 +968,7 @@
atomic_t async_submit_draining;
atomic_t nr_async_bios;
atomic_t async_delalloc_pages;
+ atomic_t open_ioctl_trans;
/*
* this is used by the balancing code to wait for all the pending
@@ -1032,6 +1032,7 @@
int closing;
int log_root_recovering;
int enospc_unlink;
+ int trans_no_join;
u64 total_pinned;
@@ -1053,7 +1054,6 @@
struct reloc_control *reloc_ctl;
spinlock_t delalloc_lock;
- spinlock_t new_trans_lock;
u64 delalloc_bytes;
/* data_alloc_cluster is only used in ssd mode */
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9d6c9e3..93ef254 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1551,22 +1551,22 @@
vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
mutex_lock(&root->fs_info->transaction_kthread_mutex);
- spin_lock(&root->fs_info->new_trans_lock);
+ spin_lock(&root->fs_info->trans_lock);
cur = root->fs_info->running_transaction;
if (!cur) {
- spin_unlock(&root->fs_info->new_trans_lock);
+ spin_unlock(&root->fs_info->trans_lock);
goto sleep;
}
now = get_seconds();
if (!cur->blocked &&
(now < cur->start_time || now - cur->start_time < 30)) {
- spin_unlock(&root->fs_info->new_trans_lock);
+ spin_unlock(&root->fs_info->trans_lock);
delay = HZ * 5;
goto sleep;
}
transid = cur->transid;
- spin_unlock(&root->fs_info->new_trans_lock);
+ spin_unlock(&root->fs_info->trans_lock);
trans = btrfs_join_transaction(root);
BUG_ON(IS_ERR(trans));
@@ -1658,7 +1658,7 @@
INIT_LIST_HEAD(&fs_info->ordered_operations);
INIT_LIST_HEAD(&fs_info->caching_block_groups);
spin_lock_init(&fs_info->delalloc_lock);
- spin_lock_init(&fs_info->new_trans_lock);
+ spin_lock_init(&fs_info->trans_lock);
spin_lock_init(&fs_info->ref_cache_lock);
spin_lock_init(&fs_info->fs_roots_radix_lock);
spin_lock_init(&fs_info->delayed_iput_lock);
@@ -1687,6 +1687,7 @@
fs_info->sb = sb;
fs_info->max_inline = 8192 * 1024;
fs_info->metadata_ratio = 0;
+ fs_info->trans_no_join = 0;
fs_info->thread_pool_size = min_t(unsigned long,
num_online_cpus() + 2, 8);
@@ -1735,7 +1736,6 @@
fs_info->do_barriers = 1;
- mutex_init(&fs_info->trans_mutex);
mutex_init(&fs_info->ordered_operations_mutex);
mutex_init(&fs_info->tree_log_mutex);
mutex_init(&fs_info->chunk_mutex);
@@ -3006,10 +3006,13 @@
WARN_ON(1);
- mutex_lock(&root->fs_info->trans_mutex);
mutex_lock(&root->fs_info->transaction_kthread_mutex);
+ spin_lock(&root->fs_info->trans_lock);
list_splice_init(&root->fs_info->trans_list, &list);
+ root->fs_info->trans_no_join = 1;
+ spin_unlock(&root->fs_info->trans_lock);
+
while (!list_empty(&list)) {
t = list_entry(list.next, struct btrfs_transaction, list);
if (!t)
@@ -3034,23 +3037,18 @@
t->blocked = 0;
if (waitqueue_active(&root->fs_info->transaction_wait))
wake_up(&root->fs_info->transaction_wait);
- mutex_unlock(&root->fs_info->trans_mutex);
- mutex_lock(&root->fs_info->trans_mutex);
t->commit_done = 1;
if (waitqueue_active(&t->commit_wait))
wake_up(&t->commit_wait);
- mutex_unlock(&root->fs_info->trans_mutex);
-
- mutex_lock(&root->fs_info->trans_mutex);
btrfs_destroy_pending_snapshots(t);
btrfs_destroy_delalloc_inodes(root);
- spin_lock(&root->fs_info->new_trans_lock);
+ spin_lock(&root->fs_info->trans_lock);
root->fs_info->running_transaction = NULL;
- spin_unlock(&root->fs_info->new_trans_lock);
+ spin_unlock(&root->fs_info->trans_lock);
btrfs_destroy_marked_extents(root, &t->dirty_pages,
EXTENT_DIRTY);
@@ -3064,8 +3062,10 @@
kmem_cache_free(btrfs_transaction_cachep, t);
}
+ spin_lock(&root->fs_info->trans_lock);
+ root->fs_info->trans_no_join = 0;
+ spin_unlock(&root->fs_info->trans_lock);
mutex_unlock(&root->fs_info->transaction_kthread_mutex);
- mutex_unlock(&root->fs_info->trans_mutex);
return 0;
}
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 941b28e..ca59965 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3200,7 +3200,8 @@
/* commit the current transaction and try again */
commit_trans:
- if (!committed && !root->fs_info->open_ioctl_trans) {
+ if (!committed &&
+ !atomic_read(&root->fs_info->open_ioctl_trans)) {
committed = 1;
trans = btrfs_join_transaction(root);
if (IS_ERR(trans))
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 75899a0..cd5e82e 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1222,14 +1222,12 @@
* the current transaction, we can bail out now without any
* syncing
*/
- mutex_lock(&root->fs_info->trans_mutex);
+ smp_mb();
if (BTRFS_I(inode)->last_trans <=
root->fs_info->last_trans_committed) {
BTRFS_I(inode)->last_trans = 0;
- mutex_unlock(&root->fs_info->trans_mutex);
goto out;
}
- mutex_unlock(&root->fs_info->trans_mutex);
/*
* ok we haven't committed the transaction yet, lets do a commit
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 908c3d4..a578620 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -2177,9 +2177,7 @@
if (ret)
goto out;
- mutex_lock(&root->fs_info->trans_mutex);
- root->fs_info->open_ioctl_trans++;
- mutex_unlock(&root->fs_info->trans_mutex);
+ atomic_inc(&root->fs_info->open_ioctl_trans);
ret = -ENOMEM;
trans = btrfs_start_ioctl_transaction(root);
@@ -2190,9 +2188,7 @@
return 0;
out_drop:
- mutex_lock(&root->fs_info->trans_mutex);
- root->fs_info->open_ioctl_trans--;
- mutex_unlock(&root->fs_info->trans_mutex);
+ atomic_dec(&root->fs_info->open_ioctl_trans);
mnt_drop_write(file->f_path.mnt);
out:
return ret;
@@ -2426,9 +2422,7 @@
btrfs_end_transaction(trans, root);
- mutex_lock(&root->fs_info->trans_mutex);
- root->fs_info->open_ioctl_trans--;
- mutex_unlock(&root->fs_info->trans_mutex);
+ atomic_dec(&root->fs_info->open_ioctl_trans);
mnt_drop_write(file->f_path.mnt);
return 0;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 8bb2566..09c30d3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2136,10 +2136,10 @@
u64 num_bytes = 0;
int ret;
- mutex_lock(&root->fs_info->trans_mutex);
+ spin_lock(&root->fs_info->trans_lock);
rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
rc->merging_rsv_size += rc->nodes_relocated * 2;
- mutex_unlock(&root->fs_info->trans_mutex);
+ spin_unlock(&root->fs_info->trans_lock);
again:
if (!err) {
num_bytes = rc->merging_rsv_size;
@@ -2208,9 +2208,9 @@
int ret;
again:
root = rc->extent_root;
- mutex_lock(&root->fs_info->trans_mutex);
+ spin_lock(&root->fs_info->trans_lock);
list_splice_init(&rc->reloc_roots, &reloc_roots);
- mutex_unlock(&root->fs_info->trans_mutex);
+ spin_unlock(&root->fs_info->trans_lock);
while (!list_empty(&reloc_roots)) {
found = 1;
@@ -3583,17 +3583,17 @@
static void set_reloc_control(struct reloc_control *rc)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- mutex_lock(&fs_info->trans_mutex);
+ spin_lock(&fs_info->trans_lock);
fs_info->reloc_ctl = rc;
- mutex_unlock(&fs_info->trans_mutex);
+ spin_unlock(&fs_info->trans_lock);
}
static void unset_reloc_control(struct reloc_control *rc)
{
struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
- mutex_lock(&fs_info->trans_mutex);
+ spin_lock(&fs_info->trans_lock);
fs_info->reloc_ctl = NULL;
- mutex_unlock(&fs_info->trans_mutex);
+ spin_unlock(&fs_info->trans_lock);
}
static int check_extent_flags(u64 flags)
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 46f4056..43816f8 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -34,6 +34,7 @@
{
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);
}
@@ -48,47 +49,73 @@
/*
* 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,
- GFP_NOFS);
- 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,
+ GFP_NOFS);
+ 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;
}
@@ -99,39 +126,28 @@
* 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)
+int btrfs_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);
+ 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;
+ }
+ root->last_trans = trans->transid;
radix_tree_tag_set(&root->fs_info->fs_roots_radix,
(unsigned long)root->root_key.objectid,
BTRFS_ROOT_TRANS_TAG);
- root->last_trans = trans->transid;
+ spin_unlock(&root->fs_info->fs_roots_radix_lock);
btrfs_init_reloc_root(trans, root);
}
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);
- return 0;
- }
-
- record_root_in_trans(trans, root);
- mutex_unlock(&root->fs_info->trans_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.
@@ -140,21 +156,23 @@
{
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 +185,16 @@
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;
}
@@ -198,23 +222,21 @@
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;
@@ -253,11 +275,7 @@
}
got_it:
- 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);
+ btrfs_record_root_in_trans(h, root);
if (!current->journal_info && type != TRANS_USERSPACE)
current->journal_info = h;
@@ -289,17 +307,13 @@
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;
}
@@ -309,50 +323,49 @@
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;
+ goto out;
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;
}
@@ -401,10 +414,8 @@
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,
@@ -422,6 +433,7 @@
struct btrfs_transaction *cur_trans = trans->transaction;
int updates;
+ smp_mb();
if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
return 1;
@@ -467,9 +479,11 @@
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)
@@ -739,9 +753,9 @@
*/
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;
}
@@ -757,6 +771,7 @@
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,
@@ -769,6 +784,7 @@
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);
@@ -783,10 +799,12 @@
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;
}
@@ -972,7 +990,7 @@
parent = dget_parent(dentry);
parent_inode = parent->d_inode;
parent_root = BTRFS_I(parent_inode)->root;
- record_root_in_trans(trans, parent_root);
+ btrfs_record_root_in_trans(trans, parent_root);
/*
* insert the directory item
@@ -990,7 +1008,7 @@
ret = btrfs_update_inode(trans, parent_root, parent_inode);
BUG_ON(ret);
- record_root_in_trans(trans, root);
+ btrfs_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);
@@ -1080,20 +1098,20 @@
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;
}
@@ -1117,9 +1135,7 @@
&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);
}
}
@@ -1145,9 +1161,7 @@
&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);
}
@@ -1193,22 +1207,18 @@
}
/* 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);
return 0;
}
@@ -1252,38 +1262,41 @@
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)
@@ -1291,12 +1304,12 @@
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);
@@ -1316,14 +1329,15 @@
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);
+ spin_lock(&root->fs_info->trans_lock);
+ root->fs_info->trans_no_join = 1;
+ spin_unlock(&root->fs_info->trans_lock);
} while (atomic_read(&cur_trans->num_writers) > 1 ||
(should_grow && cur_trans->num_joined != joined));
@@ -1364,9 +1378,6 @@
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);
@@ -1387,10 +1398,13 @@
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);
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);
@@ -1403,22 +1417,21 @@
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);
-
if (current->journal_info == trans)
current->journal_info = NULL;
@@ -1438,9 +1451,9 @@
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);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 154314f..11c6efc 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -28,10 +28,12 @@
* transaction can end
*/
atomic_t num_writers;
+ atomic_t use_count;
unsigned long num_joined;
+
+ spinlock_t commit_lock;
int in_commit;
- atomic_t use_count;
int commit_done;
int blocked;
struct list_head list;
