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-rw-r--r--fs/btrfs/file.c12
-rw-r--r--fs/btrfs/transaction.c3
-rw-r--r--fs/btrfs/transaction.h1
3 files changed, 15 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 030012e..72df63b 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1928,12 +1928,24 @@ int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
if (file->private_data)
btrfs_ioctl_trans_end(file);
+ /*
+ * We use start here because we will need to wait on the IO to complete
+ * in btrfs_sync_log, which could require joining a transaction (for
+ * example checking cross references in the nocow path). If we use join
+ * here we could get into a situation where we're waiting on IO to
+ * happen that is blocked on a transaction trying to commit. With start
+ * we inc the extwriter counter, so we wait for all extwriters to exit
+ * before we start blocking join'ers. This comment is to keep somebody
+ * from thinking they are super smart and changing this to
+ * btrfs_join_transaction *cough*Josef*cough*.
+ */
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
mutex_unlock(&inode->i_mutex);
goto out;
}
+ trans->sync = true;
ret = btrfs_log_dentry_safe(trans, root, dentry);
if (ret < 0) {
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index da2ac4c..b16352c 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -474,6 +474,7 @@ again:
h->type = type;
h->allocating_chunk = false;
h->reloc_reserved = false;
+ h->sync = false;
INIT_LIST_HEAD(&h->qgroup_ref_list);
INIT_LIST_HEAD(&h->new_bgs);
@@ -713,7 +714,7 @@ static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
btrfs_create_pending_block_groups(trans, root);
trans->delayed_ref_updates = 0;
- if (btrfs_should_throttle_delayed_refs(trans, root)) {
+ if (!trans->sync && btrfs_should_throttle_delayed_refs(trans, root)) {
cur = max_t(unsigned long, cur, 1);
trans->delayed_ref_updates = 0;
btrfs_run_delayed_refs(trans, root, cur);
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index d05b601..6ac037e 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -93,6 +93,7 @@ struct btrfs_trans_handle {
short adding_csums;
bool allocating_chunk;
bool reloc_reserved;
+ bool sync;
unsigned int type;
/*
* this root is only needed to validate that the root passed to
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