Add btrfs_end_transaction_throttle to force writers to wait for pending commits

The existing throttle mechanism was often not sufficient to prevent
new writers from coming in and making a given transaction run forever.
This adds an explicit wait at the end of most operations so they will
allow the current transaction to close.

There is no wait inside file_write, inode updates, or cow filling, all which
have different deadlock possibilities.

This is a temporary measure until better asynchronous commit support is
added.  This code leads to stalls as it waits for data=ordered
writeback, and it really needs to be fixed.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b7f8f92daf8a..ece221cba90c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -934,7 +934,6 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
                 if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
                         btrfs_btree_balance_dirty(root, 1);
-                btrfs_throttle(root);
                 cond_resched();
         }
 out: