Bug 873474 - ktarget: automatically expose backstore block size in exported LUN
Summary: ktarget: automatically expose backstore block size in exported LUN
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: kernel
Version: 7.0
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Andy Grover
QA Contact: Bruno Goncalves
URL:
Whiteboard:
: 895312 902863 (view as bug list)
Depends On: 747510
Blocks: 732980 737672 767187
TreeView+ depends on / blocked
 
Reported: 2012-11-05 23:48 UTC by Andy Grover
Modified: 2014-06-18 05:47 UTC (History)
5 users (show)

Fixed In Version: kernel-3.10.0-99.el7
Doc Type: Bug Fix
Doc Text:
Clone Of: 747510
Environment:
Last Closed: 2014-06-13 13:10:54 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Comment 1 Andy Grover 2012-11-05 23:51:50 UTC 
ensure LIO kernel target is also exposing this stuff for block and pscsi backstores:

1) READ CAPACITY(16) provides the block sizes and alignment offset:
LOGICAL BLOCK LENGTH IN BYTES:
/sys/block/<disk>/queue/physical_block_size

LOGICAL BLOCKS PER PHYSICAL BLOCK EXPONENT is used to derive:
/sys/block/<disk>/queue/logical_block_size

LOWEST ALIGNED LOGICAL BLOCK ADDRESS:
/sys/block/<disk>/alignment_offset
/sys/block/<disk>/<partition>/alignment_offset

2) BLOCK LIMITS VPD provides the "I/O hints":
OPTIMAL TRANSFER LENGTH GRANULARITY and OPTIMAL TRANSFER LENGTH are used
to derive:
/sys/block/<disk>/queue/minimum_io_size
/sys/block/<disk>/queue/optimal_io_size
Comment 2 Andy Grover 2013-01-15 19:59:36 UTC 
bug 895312 may be related to this? Not sure.
Comment 3 Andy Grover 2013-10-10 23:46:03 UTC 
*** Bug 895312 has been marked as a duplicate of this bug. ***
Comment 4 Andy Grover 2013-10-11 22:29:42 UTC 
fix posted upstream
Comment 5 Andy Grover 2013-11-20 20:50:20 UTC 
fix accepted upstream, likely will be in 3.13.
Comment 6 Andy Grover 2014-02-11 01:31:20 UTC 
*** Bug 902863 has been marked as a duplicate of this bug. ***
Comment 8 Jarod Wilson 2014-03-03 13:57:35 UTC 
Patch(es) available on kernel-3.10.0-99.el7
Comment 10 Bruno Goncalves 2014-03-04 16:16:08 UTC 
Verified using:
# rpm -q targetcli
targetcli-2.1.fb34-1.el7.noarch
# uname -r
3.10.0-99.el7.x86_64


modprobe scsi_debug num_parts=1 sector_size=4096 lowest_aligned=7 physblk_exp=3 dev_size_mb=10



# sg_inq -p 0xb0 /dev/sdb
VPD INQUIRY: Block limits page (SBC)
  Maximum compare and write length: 0 blocks
  Optimal transfer length granularity: 8 blocks
  Maximum transfer length: 2560 blocks
  Optimal transfer length: 64 blocks
  Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
  Maximum unmap LBA count: 0
  Maximum unmap block descriptor count: 0
  Optimal unmap granularity: 1
  Unmap granularity alignment valid: 0
  Unmap granularity alignment: 0


# sg_inq -p 0xb0 /dev/sdc
VPD INQUIRY: Block limits page (SBC)
  Maximum compare and write length: 0 blocks
  Optimal transfer length granularity: 8 blocks
  Maximum transfer length: 8192 blocks
  Optimal transfer length: 64 blocks
  Maximum prefetch, xdread, xdwrite transfer length: 0 blocks


# cat /sys/block/sdb/queue/physical_block_size
32768
# cat /sys/block/sdc/queue/physical_block_size
32768

# cat /sys/block/sdb/queue/logical_block_size
4096
# cat /sys/block/sdc/queue/logical_block_size
4096


# cat /sys/block/sdb/sdb1/alignment_offset
28672
# cat /sys/block/sdc/sdc1/alignment_offset
28672

# cat /sys/block/sdb/alignment_offset
28672
# cat /sys/block/sdc/alignment_offset
28672


# cat /sys/block/sdb/queue/minimum_io_size
32768
# cat /sys/block/sdc/queue/minimum_io_size
32768

# cat /sys/block/sdb/queue/optimal_io_size
262144
# cat /sys/block/sdc/queue/optimal_io_size
262144
Comment 12 Ludek Smid 2014-06-13 13:10:54 UTC 
This request was resolved in Red Hat Enterprise Linux 7.0.

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