Description of problem:

lvm should not allow extending an LV with a PV of different sector size than existing PVs making up the LV, since the FS on the LV does not mount once LVM adds in the new PV and extends the LV.


How reproducible:
Steps to Reproduce:

** Device: sdc (using the device with default sector size of 512)

# blockdev --report /dev/sdc
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw  8192   512  4096          0      1073741824   /dev/sdc

** LVM is created with the default sector size of 512.

# blockdev --report /dev/mapper/testvg-testlv 
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw  8192   512  4096          0      1069547520   /dev/mapper/testvg-testlv

** The filesystem will also pick up 512 sector size.

# mkfs.xfs /dev/mapper/testvg-testlv 
meta-data=/dev/mapper/testvg-testlv isize=512    agcount=4, agsize=65280 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=261120, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=855, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

** Now we will mount it 

# xfs_info /test
meta-data=/dev/mapper/testvg-testlv isize=512    agcount=4, agsize=65280 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=261120, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=855, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

** Let's extend it with a PV with a sector size of 4096:

#modprobe scsi_debug sector_size=4096 dev_size_mb=512

# fdisk -l /dev/sdd
 
Disk /dev/sdd: 536 MB, 536870912 bytes, 131072 sectors
Units = sectors of 1 * 4096 = 4096 bytes <==============
Sector size (logical/physical): 4096 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 262144 bytes
 
# blockdev --report /dev/sdd
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw  8192  4096  4096          0       536870912   /dev/sdd

# vgextend testvg /dev/sdd
  Physical volume "/dev/sdd" successfully created
  Volume group "testvg" successfully extended

# lvextend -l +100%FREE /dev/mapper/testvg-testlv
  Size of logical volume testvg/testlv changed from 1020.00 MiB (255 extents) to 1.49 GiB (382 extents).
  Logical volume testlv successfully resized.

# umount /test

# mount /dev/mapper/testvg-testlv /test
mount: mount /dev/mapper/testvg-testlv on /test failed: Function not implemented <===========

# dmesg | grep -i dm-2

[  477.517515] XFS (dm-2): Unmounting Filesystem
[  486.905933] XFS (dm-2): device supports 4096 byte sectors (not 512) <============

The sector size of the lv is now 4096.
# blockdev --report /dev/mapper/testvg-testlv 
RO    RA   SSZ   BSZ   StartSec            Size   Device
rw  8192  4096  4096          0      1602224128   /dev/mapper/testvg-testlv



Expected results:
LVM should fail the lvextend if sector size is different to existing PV's


Additional info:
Discussed with Zdenek during LVM meeting in Brno