[PATCH 2/4] rbd: add warning messages for missing arguments

[Alex Elder <elder@inktank.com>]

Tell the user (via dmesg) what was wrong with the arguments provided
via /sys/bus/rbd/add.

Signed-off-by: Alex Elder <elder@inktank.com>
---
 drivers/block/rbd.c |   24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 85a5164..de1d3b1 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3246,8 +3246,10 @@ static int rbd_add_parse_args(const char *buf,
 	/* The first four tokens are required */

 	len = next_token(&buf);
-	if (!len)
-		return -EINVAL;	/* Missing monitor address(es) */
+	if (!len) {
+		rbd_warn(NULL, "no monitor address(es) provided");
+		return -EINVAL;
+	}
 	mon_addrs = buf;
 	mon_addrs_size = len + 1;
 	buf += len;
@@ -3256,8 +3258,10 @@ static int rbd_add_parse_args(const char *buf,
 	options = dup_token(&buf, NULL);
 	if (!options)
 		return -ENOMEM;
-	if (!*options)
-		goto out_err;	/* Missing options */
+	if (!*options) {
+		rbd_warn(NULL, "no options provided");
+		goto out_err;
+	}

 	spec = rbd_spec_alloc();
 	if (!spec)
@@ -3266,14 +3270,18 @@ static int rbd_add_parse_args(const char *buf,
 	spec->pool_name = dup_token(&buf, NULL);
 	if (!spec->pool_name)
 		goto out_mem;
-	if (!*spec->pool_name)
-		goto out_err;	/* Missing pool name */
+	if (!*spec->pool_name) {
+		rbd_warn(NULL, "no pool name provided");
+		goto out_err;
+	}

 	spec->image_name = dup_token(&buf, NULL);
 	if (!spec->image_name)
 		goto out_mem;
-	if (!*spec->image_name)
-		goto out_err;	/* Missing image name */
+	if (!*spec->image_name) {
+		rbd_warn(NULL, "no image name provided");
+		goto out_err;
+	}

 	/*
 	 * Snapshot name is optional; default is to use "-"
-- 
1.7.9.5