Btrfs: improve the noflush reservation

In some places(such as: evicting inode), we just can not flush the reserved
space of delalloc, flushing the delayed directory index and delayed inode
is OK, but we don't try to flush those things and just go back when there is
no enough space to be reserved. This patch fixes this problem.

We defined 3 types of the flush operations: NO_FLUSH, FLUSH_LIMIT and FLUSH_ALL.
If we can in the transaction, we should not flush anything, or the deadlock
would happen, so use NO_FLUSH. If we flushing the reserved space of delalloc
would cause deadlock, use FLUSH_LIMIT. In the other cases, FLUSH_ALL is used,
and we will flush all things.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 478f66bdc57b..0c6dca550ea1 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -651,7 +651,8 @@ static int btrfs_delayed_inode_reserve_metadata(
          */
         if (!src_rsv || (!trans->bytes_reserved &&
                          src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) {
-                ret = btrfs_block_rsv_add_noflush(root, dst_rsv, num_bytes);
+                ret = btrfs_block_rsv_add(root, dst_rsv, num_bytes,
+                                          BTRFS_RESERVE_NO_FLUSH);
                 /*
                  * Since we're under a transaction reserve_metadata_bytes could
                  * try to commit the transaction which will make it return
@@ -686,7 +687,8 @@ static int btrfs_delayed_inode_reserve_metadata(
                  * reserve something strictly for us.  If not be a pain and try
                  * to steal from the delalloc block rsv.
                  */
-                ret = btrfs_block_rsv_add_noflush(root, dst_rsv, num_bytes);
+                ret = btrfs_block_rsv_add(root, dst_rsv, num_bytes,
+                                          BTRFS_RESERVE_NO_FLUSH);
                 if (!ret)
                         goto out;