Date: Fri, 7 Oct 2011 17:22:54 -0400 From: Arnaud Lacombe <lacombar@gmail.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Warren Block <wblock@wonkity.com>, Glen Barber <gjb@freebsd.org>, freebsd-current@freebsd.org, Garrett Cooper <yanegomi@gmail.com>, Benjamin Kaduk <kaduk@mit.edu> Subject: Re: aliasing (or renaming) kern.geom.debugflags Message-ID: <CACqU3MVgVUxe%2BMtaf9wq6oz5=PZAq=Sx-ihyQh1GyjD3PXmjhQ@mail.gmail.com> In-Reply-To: <4360.1318021854@critter.freebsd.dk> References: <alpine.BSF.2.00.1110071352210.2450@wonkity.com> <4360.1318021854@critter.freebsd.dk>
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Hi, On Fri, Oct 7, 2011 at 5:10 PM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrot= e: > In message <alpine.BSF.2.00.1110071352210.2450@wonkity.com>, Warren Block= write > s: > >># mount /dev/da0p2 /mnt >># dd if=3D/tmp/FreeBSD-9.0-BETA3-amd64-memstick.img of=3D/dev/da0 bs=3D64= k >>dd: /dev/da0: Operation not permitted >># sysctl kern.geom.debugflags=3D16 >>kern.geom.debugflags: 0 -> 16 >># dd if=3D/tmp/FreeBSD-9.0-BETA3-amd64-memstick.img of=3D/dev/da0 bs=3D64= k >>10463+1 records in >>10463+1 records out >>685731840 bytes transferred in 52.915362 secs (12959031 bytes/sec) >> >>Followed by removing the memory stick without unmounting it to avoid >>overwriting part of the image. =A0No obvious problems, but no, it's not >>polite. =A0(I'm thinking "automounter" here.) > > And you are sure the stick now contains what you expect ? > > If the dirty filesystem had blocks to write, it might have done so... > > debugflags are called debugflags for a reason: =A0You should never > need them, unless you are debugging a problem. > How about disabling debugflags=3D16's action unless for DIAGNOSTICS kernel = ? If you expose a setting, you cannot rely on a user not to use it even if you told him not to. As long as this is exposed and usable, it will be used, even more when it was documented. - Arnaud
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