Date: Mon, 15 Jul 2013 09:33:03 -0600 From: Alan Somers <asomers@freebsd.org> To: Selphie Keller <selphie.keller@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: GPT issues with device path lengths involving make_dev_physpath_alias Message-ID: <CAOtMX2isu9NntCU2tbXuLdbax9PLFyx46O%2BaCE3HFFRJhsMO9w@mail.gmail.com> In-Reply-To: <CAAhz9O=QN7OLWkxrOkiAnNPQmpFBKYPGSLDmVyYKYevKLawdTg@mail.gmail.com> References: <CAAhz9O=QN7OLWkxrOkiAnNPQmpFBKYPGSLDmVyYKYevKLawdTg@mail.gmail.com>
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It's a compatibility problem. If you change that constant, then any binaries built with the old value will break if they rely on it having a fixed value in a system or library call. For example, the MFIIO_QUERY_DISK ioctl in the mfi(4) driver passes a structure with an array of size SPECNAMELEN + 1. If you change SPECNAMELEN, then you'll have to add a compatibility mechanism for this ioctl. I'm sure there are other places that would have the same problem. Happy Hacking. On Sun, Jul 14, 2013 at 11:50 PM, Selphie Keller <selphie.keller@gmail.com> wrote: > hello hackers, > > I recently ran into a issue with a storage server that has some of the > drives in gpt vs mbr, tracked it down to a 64 char limit that is preventing > aliases in function make_dev_physpath_alias. I was curious if there was any > reason why this couldn't be bumped from 64 to 128 which would make room for > the device paths of gpt roughly around 94 and 96 chars long. > > - #define SPECNAMELEN > <http://fxr.watson.org/fxr/ident?im=3;i=SPECNAMELEN>; 63 > */* max length of devicename */ > + *#define SPECNAMELEN > <http://fxr.watson.org/fxr/ident?im=3;i=SPECNAMELEN>; 127 > */* max length of devicename */* > > > http://fxr.watson.org/fxr/source/sys/param.h#L106 > > Jul 14 22:10:17 fbsd9 kernel: make_dev_physpath_alias: WARNING - Unable to > alias gptid/4d177c56-ce17-26e3-843e-9c8a9faf1e0f to enc@n5003048000ba7d7d > /type@0/slot@b/elmdesc@Slot_11/gptid/4d177c56-ce17-26e3-843e-9c8a9faf1e0f - > path too long > Jul 14 22:10:17 fbsd9 kernel: make_dev_physpath_alias: WARNING - Unable to > alias gptid/4b1caf38-d967-24ee-c3a0-badff404e7ed to enc@n5003048000ba7d7d > /type@0/slot@5/elmdesc@Slot_05/gptid/4b1caf38-d967-24ee-c3a0-badff404e7ed - > path too long > > -Selphie (Estella Mystagic) > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"
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