bcache: improve error message in bch_cached_dev_run()

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>

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a836910..e9e6d65 100644 (file)
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -926,13 +926,18 @@ int bch_cached_dev_run(struct cached_dev *dc)
                NULL,
        };
 
-       if (dc->io_disable)
+       if (dc->io_disable) {
+               pr_err("I/O disabled on cached dev %s",
+                      dc->backing_dev_name);
                return -EIO;
+       }
 
        if (atomic_xchg(&dc->running, 1)) {
                kfree(env[1]);
                kfree(env[2]);
                kfree(buf);
+               pr_info("cached dev %s is running already",
+                      dc->backing_dev_name);
                return -EBUSY;
        }
 
@@ -961,7 +966,7 @@ int bch_cached_dev_run(struct cached_dev *dc)
        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;
        }