Re: store a pointer to the block_device in struct bio (again)

Qian Cai
2020-12-08T13:10:06Z

On Tue, 2020-12-08 at 12:04 +0100, Christoph Hellwig wrote:
> can you send me details of your device mapper setup, e.g. which targets
> are used, are they used on top of whole device or partitions. Do you
> use partitions on top of the dm devices? Are any other stacking devices
> involved?

It is a standard RHEL8 installation using "autopart", so I don't think it uses
any particular targets. It is just a plain LVM backed by ahci (sda2 and sdb1.
Some other affected systems use smartpqi/NVM). The kernel has only dm-mirror
enabled but I don't think it uses it anyway.

# grep -i _DM_ .config | grep -v ^#
CONFIG_BLK_DEV_DM_BUILTIN=y
CONFIG_DM_MIRROR=m
CONFIG_DM_UEVENT=y

# lvdisplay
--- Logical volume ---
LV Path /dev/rhel_ibm-p9wr-10/home
LV Name home
VG Name rhel_ibm-p9wr-10
LV UUID ETS2PI-yedc-7AJ6-NUP2-uAYD-6api-bp9nqv
LV Write Access read/write
LV Status available
# open 1
LV Size <3.57 TiB
Current LE 934662
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 254:2

--- Logical volume ---
LV Path /dev/rhel_ibm-p9wr-10/root
LV Name root
VG Name rhel_ibm-p9wr-10
LV UUID ozakb8-2DWE-YBI9-4nnc-gwk8-mMuf-s3EPsB
LV Write Access read/write
LV Status available
# open 1
LV Size 70.00 GiB
Current LE 17920
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 254:0

# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name rhel_ibm-p9wr-10
PV Size <1.82 TiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 476675
Free PE 0
Allocated PE 476675
PV UUID 0Tv2Az-vx7S-HLPd-66Ff-tH6H-dte1-tjSZ7i

--- Physical volume ---
PV Name /dev/sdb1
VG Name rhel_ibm-p9wr-10
PV Size <1.82 TiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 476931
Free PE 0
Allocated PE 476931
PV UUID 4LfZJN-NxbJ-39OC-VBKP-jv5P-hciK-BOdiML

# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 1 1.8T 0 disk
├─sda1 8:1 1 1G 0 part /boot
└─sda2 8:2 1 1.8T 0 part
├─rhel_ibm--p9wr--10-root 254:0 0 70G 0 lvm /
└─rhel_ibm--p9wr--10-home 254:2 0 3.6T 0 lvm /home
sdb 8:16 1 1.8T 0 disk
└─sdb1 8:17 1 1.8T 0 part
└─rhel_ibm--p9wr--10-home 254:2 0 3.6T 0 lvm /home