Re: kern/57134: st_size of stat on vnd raw partition sometimes is 0, causing newfs to fail

[mlelstv%serpens.de@localhost (Michael van Elst)]

The following reply was made to PR kern/57134; it has been noted by GNATS.

From: mlelstv%serpens.de@localhost (Michael van Elst)
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/57134: st_size of stat on vnd raw partition sometimes is 0, causing newfs to fail
Date: Mon, 2 Jan 2023 06:20:54 -0000 (UTC)

 hannken%mailbox.org@localhost ("J. Hannken-Illjes") writes:
 
 > This assumption is wrong for this sequence:
 > 
 > fd = open("/dev/rvnd0",)
 > ioctl(fd, VNDIOCSET,)
 > fstat(fd, &sbuf)
 > 
 > as the partition size changes AFTER open.
 
 
 Yes, sad behaviour of vnd that it uses an uninitialized unit to create
 a real unit. Makes lots of things difficult and you should better
 not rely on this detail.