Submitter : lord Status : open
Assigned Engineer : nathans Priority : 3
*Modified Date : 09/08/00 *Modified User : lord
*Modified User Domain : sgi.com *Description :
Running mkfs to build an xfs filesystem after a partition has
been mounted as ext2 has periodically failed for me. The failure
is usually this:
[root@lord /]# mkfs -t xfs -f -l size=16000b /dev/sda4
meta-data=/dev/sda4 isize=256 agcount=8, agsize=149104 blks
data = bsize=4096 blocks=1192826, imaxpct=25
= sunit=0 swidth=0 blks, unwritten=0
naming =version 2 bsize=4096
log =internal log bsize=4096 blocks=16000
.....
==========================
ADDITIONAL INFORMATION (ADD)
From: steve lord <lord@xxxxxxx>
Date: Sep 08 2000 12:55:03AM
[pvnews version: 1.71]
==========================
>
> Steve,
>
> Please let me know whether this fixes your write error.
> I've also put a mkfs binary at babylon:/tmp/mkfs.xfs -
> could you run this one too, then send me the output and
> core file which it generates.
>
This fixes the error. Interestingly enough, there was just a message
in linux-fsdevel about a size off by one error in the block
device layer.
[I have been trying to get the linear md driver to work with NTFS volumes
for several months and it never worked. - I was suspecting the NTFS driver
(after having fixed linear md and verified that at least that worked fine)
but today I finally found why it doesn't work:
There is a bug in reading/writing to block devices. - It manifests itself
in the form that partitions are too small by exactly one sector!
Even though a cfdisk shows that a partition has a certain number of
sectors, you can never seek + read and/or write to the last sector (doing
file i/o using read/write(2) [also tried fread/fwrite(3), same result]. -
Last sector doesn't seem to exist. However reading the actual hd (/dev/hdb
or /dev/sda, ie. affects both IDE and SCSI) instead of the partition
(/dev/hdb7 or whatever) the sector does exist and contains the expected
information!]
Looks like it could be related. i.e. something is lying about the size.
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