btrfs_start_transaction: wait for commits in progress to finish

btrfs_commit_transaction has to loop waiting for any writers in the
transaction to finish before it can proceed.  btrfs_start_transaction
should be polite and not join a transaction that is in the process
of being finished off.

There are a few places that can't wait, basically the ones doing IO that
might be needed to finish the transaction.  For them, btrfs_join_transaction
is added.

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

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index baf46017d0d3..0a687326c0b0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -116,7 +116,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end)
         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         int ret = 0;
 
-        trans = btrfs_start_transaction(root, 1);
+        trans = btrfs_join_transaction(root, 1);
         BUG_ON(!trans);
         btrfs_set_trans_block_group(trans, inode);
 
@@ -502,7 +502,7 @@ int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
                 return 0;
         }
 
-        trans = btrfs_start_transaction(root, 1);
+        trans = btrfs_join_transaction(root, 1);
 
         ordered_extent = btrfs_lookup_ordered_extent(inode, start);
         BUG_ON(!ordered_extent);
@@ -1812,7 +1812,7 @@ int btrfs_write_inode(struct inode *inode, int wait)
         int ret = 0;
 
         if (wait) {
-                trans = btrfs_start_transaction(root, 1);
+                trans = btrfs_join_transaction(root, 1);
                 btrfs_set_trans_block_group(trans, inode);
                 ret = btrfs_commit_transaction(trans, root);
         }
@@ -1830,7 +1830,7 @@ void btrfs_dirty_inode(struct inode *inode)
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_trans_handle *trans;
 
-        trans = btrfs_start_transaction(root, 1);
+        trans = btrfs_join_transaction(root, 1);
         btrfs_set_trans_block_group(trans, inode);
         btrfs_update_inode(trans, root, inode);
         btrfs_end_transaction(trans, root);
@@ -2395,7 +2395,7 @@ again:
                                 free_extent_map(em);
                                 em = NULL;
                                 btrfs_release_path(root, path);
-                                trans = btrfs_start_transaction(root, 1);
+                                trans = btrfs_join_transaction(root, 1);
                                 goto again;
                         }
                         write_extent_buffer(leaf, map + pg_offset, ptr,