On 2/22/22, 10:28 AM, "Benjamin Marzinski" wrote: On Fri, Feb 11, 2022 at 12:41:48PM -0800, Ritika Srivastava wrote: >> Add -P, partition scanning option to kpartx which would set >> LO_FLAGS_PARTSCAN flag during loop device creation. >> This option is same as losetup -P option. >I'm confused here. What's the benefit of doing this? Doesn't this create >partition devices, just like kpartx would? This enables partition scanning for loop devices created via kpartx. When enabled, LO_FLAGS_PARTSCAN flag will be set during loop creation via kpartx -a. On detach (kpartx -d), any partitions (/dev/loopXpY) would also be removed. It has similar use cases as losetup -P option. Currently, kpartx does not create partition loop devices (/dev/loopXpY) via kpartx -a Example: 1. Current behavior: kpartx -a does not create /dev/loop0p1 # kpartx -av test.img add map loop0p1 (252:0): 0 99937 linear /dev/loop0 64 (Notice below: /dev/loop0p1 NOT created) # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:46 /dev/loop0 2. IF -P IS USED to create loop device, /dev/loop0p1 IS created. # kpartx -av -P test.img add map loop0p1 (252:0): 0 99937 linear /dev/loop0 64 (Notice below: /dev/loop0p1 IS created) # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:50 /dev/loop0 brw-rw----. 1 root disk 259, 0 Jan 14 20:50 /dev/loop0p1 Similar behavior can also be observed during detach 1. Current Behavior: kpartx -d does NOT delete partitions # kpartx -a -v test.img # parted -a none -s /dev/loop0 mkpart primary 64s 100000s # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:54 /dev/loop0 brw-rw----. 1 root disk 259, 0 Jan 14 20:54 /dev/loop0p1 # kpartx -d test.img loop deleted : /dev/loop0 (Notice: /dev/loop0p1 NOT deleted) # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:54 /dev/loop0 brw-rw----. 1 root disk 259, 0 Jan 14 20:54 /dev/loop0p1 2. IF -P IS added while creating loop, kpartx -d DOES delete loop0p1 # kpartx -a -v -P test.img # parted -a none -s /dev/loop0 mkpart primary 64s 100000s # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:46 /dev/loop0 brw-rw----. 1 root disk 259, 0 Jan 14 20:46 /dev/loop0p1 # kpartx -d test.img loop deleted : /dev/loop0 (Notice: /dev/loop0p1 IS deleted) # ls -l /dev/loop0* brw-rw----. 1 root disk 7, 0 Jan 14 20:46 /dev/loop0 Thanks, Ritika -- dm-devel mailing list dm-devel@xxxxxxxxxx https://listman.redhat.com/mailman/listinfo/dm-devel