[PATCH v2] btrfs: improve messages when devices rescanned

[Anand Jain <anand.jain@oracle.com>]

Systems booting without the initramfs seems to scan an unusual kind
of device path. And at a later time, the device is updated to the
correct path. We generally print the process name and PID of the process
scanning the device but we don't capture the same information if the
device path is rescanned with a different pathname.

But the current message is too long, so drop the unwanted words and add
process name and PID.

While at this also update the duplicate device warning to include the
process name and PID.

Reported-by: https://bugzilla.kernel.org/show_bug.cgi?id=89721
Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
v2: adds devid and scanned

 fs/btrfs/volumes.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index dc81646b13c0..60f8ea7232b5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -942,16 +942,18 @@ static noinline struct btrfs_device *device_list_add(const char *path,
 				bdput(path_bdev);
 				mutex_unlock(&fs_devices->device_list_mutex);
 				btrfs_warn_in_rcu(device->fs_info,
-			"duplicate device fsid:devid for %pU:%llu old:%s new:%s",
-					disk_super->fsid, devid,
-					rcu_str_deref(device->name), path);
+	"duplicate device %s devid %llu generation %llu scanned by %s (%d)",
+						  path, devid, found_transid,
+						  current->comm,
+						  task_pid_nr(current));
 				return ERR_PTR(-EEXIST);
 			}
 			bdput(path_bdev);
 			btrfs_info_in_rcu(device->fs_info,
-				"device fsid %pU devid %llu moved old:%s new:%s",
-				disk_super->fsid, devid,
-				rcu_str_deref(device->name), path);
+	"devid %llu device path %s changed to %s scanned by %s (pid %d)",
+					  devid, rcu_str_deref(device->name),
+					  path, current->comm,
+					  task_pid_nr(current));
 		}
 
 		name = rcu_string_strdup(path, GFP_NOFS);
-- 
2.25.1