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+++ This bug was initially created as a clone of Bug #960284 +++

Description of problem:
On devices with logical_block_size=4096 thin_check and thin_dump can perform IO that isn't 4K aligned.

Steps to Reproduce:
# modprobe scsi_debug sector_size=4096 dev_size_mb=128
# thin_dump /dev/sdh
read failed
# strace thin_dump /dev/sdh
...
open("/dev/sdh", O_RDONLY|O_SYNC|O_DIRECT) = 3
brk(0x155f000)                          = 0x155f000
lseek(3, 0, SEEK_SET)                   = 0
read(3, 0x153d600, 4096)                = -1 EINVAL (Invalid argument)
brk(0x155e000)                          = 0x155e000

0x153d600 isn't a 4K aligned address.

(I've also seen thin_check fail IO to when reading from an mmap() buffer that isn't 4K aligned). 
  
Actual results:
Buffers aren't aligned to logical_block_size (e.g. 4K).

Expected results:
Buffers should be aligned to logical_block_size (e.g. 4K).

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

http://rhn.redhat.com/errata/RHBA-2014-1409.html