PowerFlex SDC Fails to mount scini device with error "cannot create duplicate filename"

• If an SDC has a scini device mounted that contains a partition with Partition ID in iterations of 16 (such as 16, 32, 48, 64, and so on), attempts to mount other mapped scini volumes on the SDC may fail.

• Mapping the volume from PowerFlex to the SDC is successful, but mounting the volume within the SDC fails.

• Below errors are reported in the SDC's 'messages' file.

Oct 18 11:24:17 client01 kernel: PowerFlex blkDev_Create:968 :Created device scinib (252,16). Capacity 33554432 LB
Oct 18 11:24:17 client01 kernel: sysfs: cannot create duplicate filename '/dev/block/252:16'
Oct 18 11:24:17 client01 kernel: CPU: 0 PID: 17971 Comm: blk_mgr Kdump: loaded Tainted: P        W  OE     -------  ---  5.14.0-390.el9.x86_64 #1
Oct 18 11:24:17 client01 kernel: Hardware name: VMware, Inc. VMware7,1/440BX Desktop Reference Platform, BIOS VMW71.00V.21100432.B64.2301110304 01/11/2023
Oct 18 11:24:17 client01 kernel: Call Trace:
Oct 18 11:24:17 client01 kernel: <TASK>
Oct 18 11:24:17 client01 kernel: dump_stack_lvl+0x34/0x48
Oct 18 11:24:17 client01 kernel: sysfs_warn_dup.cold+0x17/0x24
Oct 18 11:24:17 client01 kernel: sysfs_do_create_link_sd+0xce/0xe0
Oct 18 11:24:17 client01 kernel: device_add+0x3f9/0x670
Oct 18 11:24:17 client01 kernel: device_add_disk+0xdf/0x3a0
Oct 18 11:24:17 client01 kernel: blkDev_Create+0x2ab/0x760 [scini]
Oct 18 11:24:17 client01 kernel: mapVolBlkMgr_Thrd+0x2ea/0x8c0 [scini]
Oct 18 11:24:17 client01 kernel: ? mosTicks_DestroyEnvSpecific+0x10/0x10 [scini]
Oct 18 11:24:17 client01 kernel: mosOsThrd_Entry+0x1f/0x60 [scini]
Oct 18 11:24:17 client01 kernel: kthread+0xe0/0x100
Oct 18 11:24:17 client01 kernel: ? __pfx_kthread+0x10/0x10
Oct 18 11:24:17 client01 kernel: ret_from_fork+0x2c/0x50
Oct 18 11:24:17 client01 kernel: </TASK>
Oct 18 11:24:17 client01 kernel: PowerFlex blkDev_Create:983 :Error: Failed to add disk scinib (252,16). Capacity 33554432 LB

• On the SDC, the Linux kernel and scini driver provides mapped volumes a specific MAJ:MIN device numbering in iterations of 16. Example below shows three scini devices with no partitions mapped as 252:0, 252:16, 252:32
• If an SDC has a volume that contains a single partition with Partition ID of 16 (which may assign MAJ:MIN device info as 252:16, 252:32, and so on), attempts to map further volumes to SDC may fail due to a duplicate device ID already existing (even though the volume may only have one partition)

Example of numbering conflict

• Three mounted scini volumes obtain MAJ:MIN device numbering of 252:0, 252:16, 252:32
• If scinia volume contained a Partition ID of 16, the partition would be assigned MAJ:MIN device numbering of 252:16
• When scinib volume attempts to mount to the OS, it would require device ID of 252:16, which is already in use by scinia16

[root@client01 ~]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
...
scinia      252:0    0   16G  0 disk
scinib      252:16   0  120G  0 disk
scinic      252:32   0   24G  0 disk
[root@client01 ~]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
...
scinia      252:0    0   16G  0 disk
├─scinia14  252:14   0   95M  0 part
├─scinia15  252:15   0 95.5M  0 part
└─scinia16  252:16   0 95.4M  0 part
  
NOTE: This example has three partitions, but same would apply if only scinia16 existed

Behavior is by design. PowerFlex supports a maximum of 15 partitions per volume.

• Dell PowerFlex 4.5.x Technical Overview - Product Limits
  • Maximum file system partitions per volume: 15

The maximum number of partitions will be increased to 256 in future PowerFlex releases in order to avoid this enumeration conflict.

Impacted Version

All

Fixed In Version

PowerFlex Core 3.6.5 / 4.5.4