Date: Thu, 25 Aug 2005 06:17:32 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: =?iso-8859-1?q?Dag-Erling_Sm=F8rgrav?= <des@des.no> Cc: freebsd-hackers@freebsd.org, kamalp@acm.org Subject: Re: vode to pathname Message-ID: <20050825061451.D11335@fledge.watson.org> In-Reply-To: <867jeb8phr.fsf@xps.des.no> References: <20050824103243.47160.qmail@web52710.mail.yahoo.com> <867jeb8phr.fsf@xps.des.no>
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On Wed, 24 Aug 2005, Dag-Erling Smørgrav wrote: > "Kamal R. Prasad" <kamalpr@yahoo.com> writes: >> So the question is, how do I get hold of pathname given >> vnode*/(inode, devno, generation no) -without relying on the name >> cache (on freebsd)? > > You can't. The semantics of Unix file systems are such that the mapping > from file name to file is one-way. Furthermore, a file can be > associated with more than one file name, or even none at all (if it has > been unlinked but is still held open by a process). In fact, there's another troublesome edge case -- different files can also return the same name, if you have a way to generate names from linked files, due to mountpoint covering. Covered vnodes can still be accessed after the mount, if they have been opened, or if the cwd of a process is a directory (other than the mountpoint vnode) of the covered file system, and an identically named node can exist in the covering file system. Robert N M Watsonhelp
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