Initial mount with inode32 option

[Harry Edmon]

On 01/24/13 10:55, Ben Myers wrote:
> Hi Harry,
>
> On Thu, Jan 24, 2013 at 08:27:32AM -0800, Harry Edmon wrote:
>> I see that some of the discussion on the mailing list has to do with
>> smaller disk partition.
> Dave showed that filesystems which are too small to create 64 bit inodes will
> report still report an inode allocation policy of inode64 even when inode32 is
> specified in the mount options.  This doesn't mean that 64 bit inodes will be
> created.
>
>> I would like this option for big partisions
>> (i.e. 2 TB and greater)
> Lets try a 2TB filesystem:
>
> ## create a sparse file by writing a byte at 2 terabyte offset
> # xfs_io -c "pwrite 2t 1" -f 2t
> wrote 1/1 bytes at offset 2199023255552
>
> ## make a filesystem in that sparse file
> # mkfs.xfs 2t
> meta-data=2t                     isize=256    agcount=4, agsize=134217728 blks
>           =                       sectsz=512   attr=2, projid32bit=0
> data     =                       bsize=4096   blocks=536870912, imaxpct=5
>           =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0
> log      =internal log           bsize=4096   blocks=262144, version=2
>           =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
>
> ## mount it up with the loop device
> # mount -o loop,inode32 2t /mnt2
>
> # grep /mnt2 /proc/mounts
> /dev/loop0 /mnt2 xfs rw,relatime,attr2,inode32,noquota 0 0
> 				       ^^^^^^^
>
> It looks like it works as expected on a 2tb filesystem.  We specified the
> inode32 mount option and it reports an inode allocation policy of inode32 on a
> filesystem that is big enough to create 64 bit inodes.  In this situation no 64
> bit inodes will be created.
>
>> so I can have the option to continue
>> compatibility with Networker as I could with older Linux kernels.
> Based upon Dave's comments and the above I think you're in good shape.  Looks
> like I prematurely jumped to the conclusion that we have a problem.
>
> Have you run into a compatability issue that you can describe?
>
> Thanks,
> Ben
Yes, I verified that on a 2TB disk the inode32 mount option works as I expect.   
Thanks for your help.

-- 
Dr. Harry Edmon
harry at uw.edu, 206-543-0547, FAX: 206-543-0308
Director of IT, College of the Environment and
Director of Computing, Dept of Atmospheric Sciences
University of Washington, Box 351640, Seattle, WA 98195-1640