Date: Tue, 04 Sep 2001 14:27:00 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Brent Verner <brent@rcfile.org> Cc: current@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: Junior Kernel Hacker task: improve vnode->v_tag Message-ID: <12839.999606420@critter> In-Reply-To: Your message of "Tue, 04 Sep 2001 08:13:37 EDT." <20010904081337.A8968@rcfile.org>
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In message <20010904081337.A8968@rcfile.org>, Brent Verner writes: >On 04 Sep 2001 at 10:36 (+0200), Poul-Henning Kamp wrote: >| >| Assignment: >| >| The v_tag element in struct vnode is a debugging aid, but unfortunately >| it is implemented in a way which means that adding a filesystem means >| modifying the definition in <sys/vnode.h>. >| >| Convert the v_tag to an "const char *" and have the filesystems put >| their name in there instead. >| >| The v_tag has been abused a few places, easily recognizable by the fact >| that the kernel should never inspect the value of v_tag. >| These places should be easily changeable to use the new representation. >| Please mark them with a big fat "/*XXX: ABUSE OF v_tag */" comment. > >#include <newbie_kernel_hacker_warning.h> > >I've done a /cursory/ look over how this v_tag is used. I'm not sure >this is a simple/clean as you propose, since this is used in the >IS_LOCKING_VFS macro, as well as in union_subr.c... Well, that is just too bad, because IS_LOCKING_VFS is wrong then. The places which inspect v_tag will have to be changed to use strcmp() then... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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