[PATCH] btrfs: replace EINVAL with EOPNOTSUPP for dev_replace raid56

[PATCH] btrfs: replace EINVAL with EOPNOTSUPP for dev_replace raid56

[Gui Hecheng]

To return EOPNOTSUPP is more user friendly than to return EINVAL,
and then user-space tool will show that the dev_replace operation
for raid56 is not currently supported rather than showing that
there is an invalid argument.

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
---
 fs/btrfs/dev-replace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 9f22905..2af6e66 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -313,7 +313,7 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 
 	if (btrfs_fs_incompat(fs_info, RAID56)) {
 		btrfs_warn(fs_info, "dev_replace cannot yet handle RAID5/RAID6");
-		return -EINVAL;
+		return -EOPNOTSUPP;
 	}
 
 	switch (args->start.cont_reading_from_srcdev_mode) {
-- 
1.8.1.4

[PATCH] btrfs-progs: show meaningful msgs for replace cmd upon raid56

[Gui Hecheng]

This depends on the kernel patch:
	[PATCH] btrfs:replace EINVAL with EOPNOTSUPP for dev_replace

This catches the EOPNOTSUPP and output msg that says dev_replace raid56
is not currently supported. Note that the msg will only be shown when
run dev_replace not in background.

Signed-off-by: Gui Hecheng <guihc.fnst@cn.fujitsu.com>
---
 cmds-replace.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cmds-replace.c b/cmds-replace.c
index 9eb981b..8b18110 100644
--- a/cmds-replace.c
+++ b/cmds-replace.c
@@ -301,6 +301,10 @@ static int cmd_start_replace(int argc, char **argv)
 				"ERROR: ioctl(DEV_REPLACE_START) failed on \"%s\": %s, %s\n",
 				path, strerror(errno),
 				replace_dev_result2string(start_args.result));
+
+			if (errno == EOPNOTSUPP)
+				fprintf(stderr, "WARNING: dev_replace cannot yet handle RAID5/RAID6\n");
+
 			goto leave_with_error;
 		}
 
-- 
1.8.1.4