xfs: saner xfs_trans_commit interface

The flags argument to xfs_trans_commit is not useful for most callers, as
a commit of a transaction without a permanent log reservation must pass
0 here, and all callers for a transaction with a permanent log reservation
except for xfs_trans_roll must pass XFS_TRANS_RELEASE_LOG_RES.  So remove
the flags argument from the public xfs_trans_commit interfaces, and
introduce low-level __xfs_trans_commit variant just for xfs_trans_roll
that regrants a log reservation instead of releasing it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
index b5573bf..2d90452 100644
--- a/fs/xfs/xfs_symlink.c
+++ b/fs/xfs/xfs_symlink.c
@@ -390,7 +390,7 @@
 	if (error)
 		goto out_bmap_cancel;
 
-	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+	error = xfs_trans_commit(tp);
 	if (error)
 		goto out_release_inode;
 
@@ -528,7 +528,7 @@
 	/*
 	 * Commit the transaction containing extent freeing and EFDs.
 	 */
-	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
+	error = xfs_trans_commit(tp);
 	if (error) {
 		ASSERT(XFS_FORCED_SHUTDOWN(mp));
 		goto error_unlock;