On 10 Feb 2015, J. Bruce Fields said: > On Tue, Feb 10, 2015 at 05:48:48PM +0000, Nix wrote: >> On 5 Feb 2015, NeilBrown spake thusly: >> >> > On Wed, 04 Feb 2015 23:28:17 +0000 Nix <nix@xxxxxxxxxxxxx> wrote: >> >> It doesn't. It still recurs. >> > >> > Is /usr/archive still exported to mutilate with crossmnt? >> > If it is, can you change to not do that (it is quite possible to have >> > different export options for different clients). >> >> OK. Adjusted. >> >> > I think that if crossmnt is enabled on the server, then explicitly >> > mounting /usr/archive/series will have the same net effect as not doing so >> > (though I'm not 100% certain). >> > >> > Also, can you try changing >> > /proc/sys/fs/nfs/nfs_mountpoint_timeout >> > >> > It defaults to 500 (seconds - time for light from Sun to reach Earth). >> > If you make it smaller and the problem gets worse, or make it much bigger >> > and the problem goes away, that would be interesting. >> > If it makes no difference, that also would be interesting. >> >> Seems to make no difference, which is distinctly surprising. If >> anything, it happens more often at the default value than at either the >> high or low values. It's very erratic: it happened ten times in one day, >> then three days passed and it didn't happen at all... system under >> very similar load the whole time. >> >> >From other prompts, what I'm seeing now -- but wasn't then, before I >> took the crossmnt out -- is an epidemic of spontaneous unmounting: i.e., >> /usr/archive/series suddenly vanishes until remounted. >> >> I might just reboot all systems involved in this mess and hope it goes >> away. I have no *clue* what's going on, I've never seen it before, maybe >> it'll stop if I no longer believe in it. > > It might be interesting to see output from > > rpc.debug -m rpc -s cache > cat /proc/net/rpc/nfsd.export/content > cat /proc/net/rpc/nfsd.fh/content > > especially after the problem manifests. It's manifested right now, as a matter of fact. # cat /proc/net/rpc/nfsd.export/content #path domain(flags) /usr/src mutilate.wkstn.nix(rw,no_root_squash,async,wdelay,no_subtree_check,fsid=16,uuid=333950aa:8e3f440a:bc94d0cc:4adae198,sec=1) /usr/share/texlive mutilate.wkstn.nix(rw,no_root_squash,async,wdelay,fsid=7,uuid=5cccc224:a92440ee:b4450447:3898c2ec,sec=1) /home/.spindle.srvr.nix mutilate.wkstn.nix(rw,no_root_squash,async,wdelay,no_subtree_check,fsid=1,uuid=95bd22c2:253c456f:8e36b6cf:b9ecd4ef,sec=1) /usr/archive/series *.srvr.nix,xios.srvr.nix(ro,insecure,root_squash,async,wdelay,no_subtree_check,fsid=29,uuid=543a1ca9:d17246ca:b6c53092:5896549d,sec=1) /usr/lib/X11/fonts mutilate.wkstn.nix(ro,root_squash,async,wdelay,fsid=12,uuid=5cccc224:a92440ee:b4450447:3898c2ec,sec=1) /home/.spindle.srvr.nix *.srvr.nix,fold.srvr.nix(rw,root_squash,async,wdelay,no_subtree_check,fsid=1,uuid=95bd22c2:253c456f:8e36b6cf:b9ecd4ef,sec=1) /usr/archive mutilate.wkstn.nix(rw,insecure,root_squash,async,wdelay,fsid=25,uuid=d20e3edd:06a54a9b:85dcfa19:62975969,sec=1) # note: no /usr/archive/series, though I mounted it on mutilate and did # not unmount it: however, it no longer appears in /proc/mounts on # mutilate and appears as an empty directory under /usr/archive. # However, it *does* appear here: # cat /proc/net/rpc/nfsd.fh/content #domain fsidtype fsid [path] *.srvr.nix,xios.srvr.nix 1 0x0000001d /usr/archive/series mutilate.wkstn.nix 1 0x0000000f /etc/shai-hulud mutilate.wkstn.nix 1 0x0000000b /pkg/non-free mutilate.wkstn.nix 1 0x00000016 /usr/share/emacs/site-lisp mutilate.wkstn.nix 1 0x00000012 /usr/share/httpd/htdocs/munin mutilate.wkstn.nix 1 0x00000013 /usr/share/clamav mutilate.wkstn.nix 1 0x0000000a /usr/share/nethack mutilate.wkstn.nix 1 0x00000009 /usr/share/xplanet mutilate.wkstn.nix 1 0x00000008 /usr/share/xemacs mutilate.wkstn.nix 1 0x00000015 /usr/share/flightgear mutilate.wkstn.nix 1 0x00000005 /usr/doc mutilate.wkstn.nix 1 0x00000006 /usr/info mutilate.wkstn.nix 1 0x00000011 /var/state/munin mutilate.wkstn.nix 1 0x0000000e /var/log.real mutilate.wkstn.nix 1 0x00000007 /usr/share/texlive mutilate.wkstn.nix 1 0x00000010 /usr/src mutilate.wkstn.nix 1 0x0000000c /usr/lib/X11/fonts mutilate.wkstn.nix 1 0x00000019 /usr/archive mutilate.wkstn.nix 1 0x0000001d /usr/archive/series mutilate.wkstn.nix 1 0x00000001 /home/.spindle.srvr.nix *.srvr.nix,fold.srvr.nix 1 0x00000001 /home/.spindle.srvr.nix When this happens, I get an (unreachable) and broken symlink under /proc (not really surprising as the mountpoint has gone) -- but in this situation, cd'ing out and back in does not fix it, only a remount does. I'm not surprised by *those* symptoms at all. > Also, /usr/archive/series is a separate filesystem from /usr/archive, > right? (The output of "mount" run on the server might also be useful.) They are separate server filesystems: /dev/mapper/main-archive /usr/archive ext4 rw,nosuid,nodev,relatime,nobarrier,commit=30,data=ordered 0 0 /dev/sdc1 /usr/archive/series ext4 rw,nosuid,nodev,relatime,commit=30,data=ordered 0 0 /dev/mapper/main-winbackup /usr/archive/winbackup ext4 rw,nosuid,nodev,relatime,nobarrier,commit=30,data=ordered 0 0 > The reason crossmnt is considered "bad and evil" is that nfsv2 and v3 > clients don't necessarily expect mountpoints within exports, and may be > get confused when (for example), they discover to files with the same > inode number that appear to be on the same filesystem. That I expected. NFS mounts within NFS mounts are presumably fine (I hope so, I've been using them extensively for decades). > I'm not actually sure what the current linux client does--I think it > may be smart enough to use the fsid to avoid at least some of those > problems. But NFSv4 clients are the only ones that should really be > counted on to get this right. I wish I could get NFSv4 to work. It's just screamed about a lack of adequate authentication every time I've tried it, and my network is so NFS-dependent that significant experimentation is difficult (getting anything wrong tends to cause my entire desktop to deadlock in seconds). I suppose I should set up some VMs and play in there :) -- NULL && (void) -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
