Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph...

[pandora-kernel.git] / fs / btrfs / transaction.c

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 5b158da..c571734 100644 (file)
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -32,10 +32,8 @@
 
 static noinline void put_transaction(struct btrfs_transaction *transaction)
 {
-       WARN_ON(transaction->use_count == 0);
-       transaction->use_count--;
-       if (transaction->use_count == 0) {
-               list_del_init(&transaction->list);
+       WARN_ON(atomic_read(&transaction->use_count) == 0);
+       if (atomic_dec_and_test(&transaction->use_count)) {
                memset(transaction, 0, sizeof(*transaction));
                kmem_cache_free(btrfs_transaction_cachep, transaction);
        }
@@ -60,14 +58,14 @@ static noinline int join_transaction(struct btrfs_root *root)
                if (!cur_trans)
                        return -ENOMEM;
                root->fs_info->generation++;
-               cur_trans->num_writers = 1;
+               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;
-               cur_trans->use_count = 1;
+               atomic_set(&cur_trans->use_count, 1);
                cur_trans->commit_done = 0;
                cur_trans->start_time = get_seconds();
 
@@ -88,7 +86,7 @@ static noinline int join_transaction(struct btrfs_root *root)
                root->fs_info->running_transaction = cur_trans;
                spin_unlock(&root->fs_info->new_trans_lock);
        } else {
-               cur_trans->num_writers++;
+               atomic_inc(&cur_trans->num_writers);
                cur_trans->num_joined++;
        }
 
@@ -145,7 +143,7 @@ static void wait_current_trans(struct btrfs_root *root)
        cur_trans = root->fs_info->running_transaction;
        if (cur_trans && cur_trans->blocked) {
                DEFINE_WAIT(wait);
-               cur_trans->use_count++;
+               atomic_inc(&cur_trans->use_count);
                while (1) {
                        prepare_to_wait(&root->fs_info->transaction_wait, &wait,
                                        TASK_UNINTERRUPTIBLE);
@@ -181,6 +179,7 @@ static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
 {
        struct btrfs_trans_handle *h;
        struct btrfs_transaction *cur_trans;
+       int retries = 0;
        int ret;
 
        if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
@@ -204,7 +203,7 @@ again:
        }
 
        cur_trans = root->fs_info->running_transaction;
-       cur_trans->use_count++;
+       atomic_inc(&cur_trans->use_count);
        if (type != TRANS_JOIN_NOLOCK)
                mutex_unlock(&root->fs_info->trans_mutex);
 
@@ -224,10 +223,18 @@ again:
 
        if (num_items > 0) {
                ret = btrfs_trans_reserve_metadata(h, root, num_items);
-               if (ret == -EAGAIN) {
+               if (ret == -EAGAIN && !retries) {
+                       retries++;
                        btrfs_commit_transaction(h, root);
                        goto again;
+               } else if (ret == -EAGAIN) {
+                       /*
+                        * We have already retried and got EAGAIN, so really we
+                        * don't have space, so set ret to -ENOSPC.
+                        */
+                       ret = -ENOSPC;
                }
+
                if (ret < 0) {
                        btrfs_end_transaction(h, root);
                        return ERR_PTR(ret);
@@ -327,7 +334,7 @@ int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
                        goto out_unlock;  /* nothing committing|committed */
        }
 
-       cur_trans->use_count++;
+       atomic_inc(&cur_trans->use_count);
        mutex_unlock(&root->fs_info->trans_mutex);
 
        wait_for_commit(root, cur_trans);
@@ -457,18 +464,14 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
                        wake_up_process(info->transaction_kthread);
        }
 
-       if (lock)
-               mutex_lock(&info->trans_mutex);
        WARN_ON(cur_trans != info->running_transaction);
-       WARN_ON(cur_trans->num_writers < 1);
-       cur_trans->num_writers--;
+       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 (lock)
-               mutex_unlock(&info->trans_mutex);
 
        if (current->journal_info == trans)
                current->journal_info = NULL;
@@ -1178,7 +1181,7 @@ int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
        /* take transaction reference */
        mutex_lock(&root->fs_info->trans_mutex);
        cur_trans = trans->transaction;
-       cur_trans->use_count++;
+       atomic_inc(&cur_trans->use_count);
        mutex_unlock(&root->fs_info->trans_mutex);
 
        btrfs_end_transaction(trans, root);
@@ -1237,7 +1240,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
        mutex_lock(&root->fs_info->trans_mutex);
        if (cur_trans->in_commit) {
-               cur_trans->use_count++;
+               atomic_inc(&cur_trans->use_count);
                mutex_unlock(&root->fs_info->trans_mutex);
                btrfs_end_transaction(trans, root);
 
@@ -1259,7 +1262,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                prev_trans = list_entry(cur_trans->list.prev,
                                        struct btrfs_transaction, list);
                if (!prev_trans->commit_done) {
-                       prev_trans->use_count++;
+                       atomic_inc(&prev_trans->use_count);
                        mutex_unlock(&root->fs_info->trans_mutex);
 
                        wait_for_commit(root, prev_trans);
@@ -1300,14 +1303,14 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
                                TASK_UNINTERRUPTIBLE);
 
                smp_mb();
-               if (cur_trans->num_writers > 1)
+               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 (cur_trans->num_writers > 1 ||
+       } while (atomic_read(&cur_trans->num_writers) > 1 ||
                 (should_grow && cur_trans->num_joined != joined));
 
        ret = create_pending_snapshots(trans, root->fs_info);
@@ -1394,6 +1397,7 @@ int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 
        wake_up(&cur_trans->commit_wait);
 
+       list_del_init(&cur_trans->list);
        put_transaction(cur_trans);
        put_transaction(cur_trans);