On Tue, Nov 26, 2013 at 06:31:19PM -0800, Phil White wrote: > Gents: > > I was making an image for a VM using everyone's favorite fs with a line > that looked something like this: > ------------- > dd if=/dev/zero of=~/image bs=1024 count=1048576 && ./mkfs/mkfs.xfs && mount -o loop ~/image /mnt/loop > ------------- > > > mkfs.xfs gave me this output: > ------------- > meta-data=/root/image isize=256 agcount=4, agsize=65536 blks > = sectsz=512 attr=2, projid32bit=0 > data = bsize=4096 blocks=262144, imaxpct=25 > = sunit=0 swidth=0 blks > naming =version 2 bsize=4096 ascii-ci=0 > log =internal log bsize=4096 blocks=2560, version=2 > = sectsz=512 sunit=0 blks, lazy-count=1 > realtime =none extsz=4096 blocks=0, rtextents=0 > existing superblock read failed: Invalid argument > mkfs.xfs: pwrite64 failed: Invalid argument > mkfs.xfs: read failed: Invalid argument > ------------- ..... > > While it occurred to me that the problem might just be line 806 of some files > in xfsprogs, I threw it under a debugger and took a closer look. The file > descriptor value in xi->dfd pointed at ~/image. errno was set to 22. I > thought that might indicate a problem with lseek(), so I rewrote the pwrite64() > and pread() as lseek()s and read()/write() > > As you may have guessed, this did me no good at all. > > It's trying to read/write 512 bytes at the beginning of the file which seems > reasonably innocuous. I double checked the man page which says that under > 2.6, O_DIRECT writes can be aligned to 512 bytes without a problem. That doesn't mean it is correct, because the man page also says: " In Linux alignment restrictions vary by filesystem and kernel version and might be absent entirely." So, I bet that your underlying filesystem (i.e. the host filesystem) has a sector size of 4k, and that's why direct Io on 512 byte alignment is failing. In that case, run "mkfs.xfs -s size=4k ..." and mkfs should just work fine... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
