[PATCH 3/3] btrfs-progs: Show error message if btrfs filesystem show failed to find any btrfs filesystem

[PATCH 3/3] btrfs-progs: Show error message if btrfs filesystem show failed to find any btrfs filesystem

[Satoru Takeuchi]

From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>

Current btrfs doesn't display any error message if this command
failed to find any btrfs filesystem corresponding to
<path>|<uuid>|<device>|<label> which user specified.

Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>

---
 cmds-filesystem.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 7633f1f..2f78e24 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -695,6 +695,7 @@ static int cmd_show(int argc, char **argv)
 		ret = btrfs_scan_kernel(search);
 	if (search && !ret) {
 		/* since search is found we are done */
+		found = 1;
 		goto out;
 	}
 
@@ -729,6 +730,15 @@ devs_only:
 		btrfs_close_devices(fs_devices);
 	}
 out:
+	if (search && !found) {
+		fprintf(stderr,
+			"ERROR: Couldn't find any btrfs filesystem "
+			"matches with '%s'.\n", search);
+		fprintf(stderr,
+			"Please check if both '%s' and the range of scanning "
+			"are correct.\n", search);
+	}
+
 	printf("%s\n", BTRFS_BUILD_VERSION);
 	free_seen_fsid();
 	return ret;
-- 
1.9.3

Re: [PATCH 3/3] btrfs-progs: Show error message if btrfs filesystem show failed to find any btrfs filesystem

[David Sterba]

On Mon, Aug 11, 2014 at 06:13:03PM +0900, Satoru Takeuchi wrote:
> From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
> 
> Current btrfs doesn't display any error message if this command
> failed to find any btrfs filesystem corresponding to
> <path>|<uuid>|<device>|<label> which user specified.

I'm not sure if it is necessary to print anything. Like if grep printed
"Sorry I did not find any lines, please check your regexp"

Although, we can add a non-zero return value if there was anything found
or not.