Date: Fri, 4 Feb 2011 08:09:09 +1100 From: Peter Jeremy <peterjeremy@acm.org> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-fs@freebsd.org Subject: Re: ext2fs crash in -current (r218056) Message-ID: <20110203210909.GA28604@server.vk2pj.dyndns.org> In-Reply-To: <20110203151318.GA9986@icarus.home.lan> References: <4D47B954.3010600@FreeBSD.org> <201102021704.04274.jhb@freebsd.org> <20110202222023.GA45401@icarus.home.lan> <201102030753.55820.jhb@freebsd.org> <20110203140142.GH78089@deviant.kiev.zoral.com.ua> <20110203151318.GA9986@icarus.home.lan>
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On 2011-Feb-03 07:13:18 -0800, Jeremy Chadwick <freebsd@jdc.parodius.com> w=
rote:
>The offset and the length are both explicitly casted and printed as
>signed numbers here.
>
>For me anyway, the next question is "what are bio_offset and bio_length
>defined as?" (indirectly, "why the explicit cast?"). They're both
>declared as part of struct bio in src/sys/sys/bio.h as shown:
>
> 71 struct bio {
>...
> 78 off_t bio_offset; /* Offset into file. */
>...
> 92 off_t bio_length; /* Like bio_bcount */
>...
off_t is always a 64-bit signed int and there's no printf(9) length
modifier to handle this particular situation (it's typically 'long' on
64-bit archs and 'long long' on 32-bit archs). Instead it's cast to a
signed int which is at least as large that does have a suitable length
modifier (intmax_t can be printed using %jd).
--=20
Peter Jeremy
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