| Message ID | alpine.LRH.2.02.2103170644080.32577@file01.intranet.prod.int.rdu2.redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: remove the "detected capacity change" message | expand |
No, it is everything but useless. It is not needed during device creation, but that is something that the GENHD_FL_UP check should catch. You should probably audit the device mapper code why it sets the initial capacity when the gendisk is up already, as that can cause all kinds of problems. If the setting of the initial capacity after add_disk is indeed intentional you can switch to set_capacity(), but you should probably document the rationale in a detailed comment.
On Wed, 17 Mar 2021, Christoph Hellwig wrote: > No, it is everything but useless. It is not needed during device > creation, but that is something that the GENHD_FL_UP check should catch. > > You should probably audit the device mapper code why it sets the initial > capacity when the gendisk is up already, as that can cause all kinds of > problems. If the setting of the initial capacity after add_disk is > indeed intentional you can switch to set_capacity(), but you should > probably document the rationale in a detailed comment. BTW. the loop device has the same problem as device mapper - it also prints "loop0: detected capacity change from 0 to 2097152" when it is being activated. Would you accept this patch? Or do you think that we should change device mapper and the loopback driver to call "set_capacity" on the initial device creation? Mikulas --- block/genhd.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) Index: linux-2.6/block/genhd.c =================================================================== --- linux-2.6.orig/block/genhd.c 2021-03-17 16:26:11.000000000 +0100 +++ linux-2.6/block/genhd.c 2021-03-17 16:26:42.000000000 +0100 @@ -71,16 +71,16 @@ bool set_capacity_and_notify(struct gend if (size == capacity || (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) return false; - - pr_info("%s: detected capacity change from %lld to %lld\n", - disk->disk_name, capacity, size); - /* * Historically we did not send a uevent for changes to/from an empty * device. */ if (!capacity || !size) return false; + + pr_info("%s: detected capacity change from %lld to %lld\n", + disk->disk_name, capacity, size); + kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); return true; }
Index: linux-2.6/block/genhd.c =================================================================== --- linux-2.6.orig/block/genhd.c 2021-03-17 11:03:52.000000000 +0100 +++ linux-2.6/block/genhd.c 2021-03-17 11:04:27.000000000 +0100 @@ -72,9 +72,6 @@ bool set_capacity_and_notify(struct gend (disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP) return false; - pr_info("%s: detected capacity change from %lld to %lld\n", - disk->disk_name, capacity, size); - /* * Historically we did not send a uevent for changes to/from an empty * device.
Every time a new device mapper device is created, a message "detected capacity change from 0 to 2097152" is reported. This message is useless, so this patch removes it. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- block/genhd.c | 3 --- 1 file changed, 3 deletions(-)