[RFC PATCH v4 7/8] xfs: reserve blocks for truncating realtime inode

[Zhang Yi <yi.zhang@huaweicloud.com>]

From: Zhang Yi <yi.zhang@huawei.com>

On a realtime inode, __xfs_bunmapi() could convert the unaligned extra
blocks to unwritten state, but it couldn't work as expected on truncate
down since the reserved block is zero in xfs_setattr_size(), fix this by
reserved XFS_IS_REALTIME_INODE blocks for realtime inode.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/xfs/xfs_iops.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ec7b7bdf8825..c53de5e6ef66 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -17,6 +17,8 @@
 #include "xfs_da_btree.h"
 #include "xfs_attr.h"
 #include "xfs_trans.h"
+#include "xfs_trans_space.h"
+#include "xfs_bmap_btree.h"
 #include "xfs_trace.h"
 #include "xfs_icache.h"
 #include "xfs_symlink.h"
@@ -811,6 +813,7 @@ xfs_setattr_size(
 	struct xfs_trans	*tp;
 	int			error;
 	uint			lock_flags = 0;
+	uint			resblks;
 	bool			did_zeroing = false;
 	bool			write_back = false;
 
@@ -932,7 +935,9 @@ xfs_setattr_size(
 		}
 	}
 
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	resblks = XFS_IS_REALTIME_INODE(ip) ? XFS_DIOSTRAT_SPACE_RES(mp, 0) : 0;
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, resblks,
+				0, 0, &tp);
 	if (error)
 		return error;
 
-- 
2.39.2