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Message-ID: <20071207200655.GD2204@fieldses.org> Date: Fri, 7 Dec 2007 15:06:55 -0500 From: "J. Bruce Fields" <bfields@...ldses.org> To: Erez Zadok <ezk@...sunysb.edu> Cc: linux-kernel@...r.kernel.org, nfs@...ts.sourceforge.net, "Eric W. Biederman" <ebiederm@...ssion.com>, "Rafael J. Wysocki" <rjw@...k.pl>, Pavel Machek <pavel@....cz>, Pavel Emelyanov <xemul@...nvz.org>, "David S. Miller" <davem@...emloft.net>, Ingo Molnar <mingo@...e.hu>, Andrew Morton <akpm@...ux-foundation.org>, Herbert Xu <herbert@...dor.apana.org.au> Subject: Re: [NFS] NFSv2/3 broken exporting/mounting (permission denied) in 2.6.24-rc4 On Fri, Dec 07, 2007 at 03:00:13PM -0500, Erez Zadok wrote: > In message <20071207025504.GA3070@...ldses.org>, "J. Bruce Fields" writes: > > On Thu, Dec 06, 2007 at 09:20:41PM -0500, Erez Zadok wrote: > > > I get a "permission denied" when trying to mount a localhost nfsv2/3 > > > exported volume, on v2.6.24-rc4-124-gf194d13. It works w/ nfsv4 mounting. > > > It worked fine in 2.6.24-rc3. Here's a sequence of ops I tried: > > > > > > # mount -t ext2 /dev/hdb1 /n/lower/b0 > > > # exportfs -o no_root_squash,rw localhost:/n/lower/b0 > > > # mount -t nfs -o nfsvers=3 localhost:/n/lower/b0 /mnt > > > > What do you see if you watch the network traffic in ethereal? > > > > --b. > > Bruce, I'm using nfs-utils-1.0.10-14.fc6 on an FC6 system with all latest > FC6 patches. Using git-bisect I was able to find the patch which broke it: Wow, thanks for your work finding that. > > commit 2b1e300a9dfc3196ccddf6f1d74b91b7af55e416 > Author: Eric W. Biederman <ebiederm@...ssion.com> > Date: Sun Dec 2 00:33:17 2007 +1100 > > [NETNS]: Fix /proc/net breakage > > Well I clearly goofed when I added the initial network namespace support > for /proc/net. Currently things work but there are odd details visible to > user space, even when we have a single network namespace. > > Since we do not cache proc_dir_entry dentries at the moment we can just > modify ->lookup to return a different directory inode depending on the > network namespace of the process looking at /proc/net, replacing the > current technique of using a magic and fragile follow_link method. > > To accomplish that this patch: > - introduces a shadow_proc method to allow different dentries to > be returned from proc_lookup. > - Removes the old /proc/net follow_link magic > - Fixes a weakness in our not caching of proc generic dentries. > > As shadow_proc uses a task struct to decided which dentry to return we can > go back later and fix the proc generic caching without modifying any code > that uses the shadow_proc method. > > Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com> > Cc: "Rafael J. Wysocki" <rjw@...k.pl> > Cc: Pavel Machek <pavel@....cz> > Cc: Pavel Emelyanov <xemul@...nvz.org> > Cc: "David S. Miller" <davem@...emloft.net> > Cc: Ingo Molnar <mingo@...e.hu> > Signed-off-by: Andrew Morton <akpm@...ux-foundation.org> > Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au> > > With the above patch, rpc.mountd is unable to open /proc/fs/nfsd/filehandle. > Strace shows: > > open("/proc/fs/nfsd/filehandle", O_RDWR|O_LARGEFILE) = -1 ENOENT (No such file or directory) > > Without the above patch, /proc/fs/nfsd is populated with a number of files, > including "filehandle". Those files are actually in a separate filesystem (of type "nfsd") which is supposed to be mounted on /proc/fs/nfsd/. So that mount must have failed in the bad case? It's not immediately obvious to me what this patch has to do with that. Hm. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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