Date: Sat, 24 Nov 2007 01:12:36 -0800 From: Julian Elischer <julian@elischer.org> To: Dan Nelson <dnelson@allantgroup.com> Cc: Alan Cox <alc@cs.rice.edu>, FreeBSD Current <current@freebsd.org> Subject: Re: suggested ways of faking EIO? Message-ID: <4747EB04.3080009@elischer.org> In-Reply-To: <20071124064711.GB4226@dan.emsphone.com> References: <4747A9B8.9080403@elischer.org> <20071124064711.GB4226@dan.emsphone.com>
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Dan Nelson wrote: > In the last episode (Nov 23), Julian Elischer said: >> I need to make physio make a request from disk, and have the request >> come back asynchronously with an EIO. >> >> I have tried just reading some distance past the end of a partition, >> but I'm not totally convinced that it acts exactly like as if I'd >> tried to read a bad sector. Since geom has been added, the legality >> of a read needs to be tested in the geometry layer, so I suppose it >> must come back asynchronously, as that is no longer directly executed >> through function calls but is it really the same as a disk failure? >> >> Anyone done this? or does anyone have a disk with a known bad sector >> I can try my test case on? :-) > > The geom NOP module can fail a given percentage of I/O with whatever > error number you choose. You could hack g_nop.c to make it fail on a > given sector instead. > great! that's the hint I'm looking for... (now to work out how to use it)
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