From e0faa3d7f79f7e1abb43de168e88c76061518ea4 Mon Sep 17 00:00:00 2001
From: Coly Li <colyli@suse.de>
Date: Fri, 28 Jun 2019 19:59:39 +0800
Subject: [PATCH] bcache: improve error message in bch_cached_dev_run()
Git-commit: e0faa3d7f79f7e1abb43de168e88c76061518ea4
References: bsc#1140652
Patch-mainline: v5.3-rc1

This patch adds more error message in bch_cached_dev_run() to indicate
the exact reason why an error value is returned. Please notice when
printing out the "is running already" message, pr_info() is used here,
because in this case also -EBUSY is returned, the bcache device can
continue to attach to the cache devince and run, so it won't be an
error level message in kernel message.

Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

---
 drivers/md/bcache/super.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -929,8 +929,11 @@ int bch_cached_dev_run(struct cached_dev
 		NULL,
 	};
 
-	if (dc->io_disable)
+	if (dc->io_disable) {
+		pr_err("I/O disabled on cached dev %s",
+		       dc->backing_dev_name);
 		return -EIO;
+	}
 
 	memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
 	buf[SB_LABEL_SIZE] = '\0';
@@ -939,6 +942,8 @@ int bch_cached_dev_run(struct cached_dev
 	if (atomic_xchg(&dc->running, 1)) {
 		kfree(env[1]);
 		kfree(env[2]);
+		pr_info("cached dev %s is running already",
+			dc->backing_dev_name);
 		return -EBUSY;
 	}
 
@@ -966,7 +971,7 @@ int bch_cached_dev_run(struct cached_dev
 	if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
 	    sysfs_create_link(&disk_to_dev(d->disk)->kobj,
 			      &d->kobj, "bcache")) {
-		pr_debug("error creating sysfs link");
+		pr_err("Couldn't create bcache dev <-> disk sysfs symlinks");
 		return -ENOMEM;
 	}