Thank you for the detailed answer! At this point I'm certain that my problem comes from nfs utils, i.e. mount.nfs, directly and is not related to FS-Cache. I mailed a detailed description of the issue to linux-nfs@xxxxxxxxxxxxxxx and it seems that the problem is [partially] solved in more recent kernels. Cheers Daniel David Howells wrote: > Daniel Goering <g_daniel@xxxxxxx> wrote: > >> I'd like to mount an NFS4 share with the option bg as described in man 5 >> nfs. >> This works perfectly fine e.g. on a Gentoo system. I tried the same with >> some Fedora 12 clients and the bg option just seems to be ignored. All >> mounts are carried out in the foreground and time out after 2 minutes >> [and the client is blocked e.g. during boot for the entire time] instead >> of trying in the background for about 1 week until the server is back up. > > Have you logged this with bugzilla? > >> The only difference I could find was that Fedora 12 automatically tries >> to use FS-Cache when issuing the mount and may be FS-Cache forces the >> whole task into the foreground... > > It does not. > > Apart from setting up a couple of memory structures, no cache-related activity > is done during mount. Nothing more happens until the first regular file is > opened for reading. Certainly nothing will happen unless you specify an 'fsc' > option on the mount command line. You can check this: > > [root@andromeda ~]# cat /proc/fs/nfsfs/volumes > NV SERVER PORT DEV FSID FSC > v4 5a9b4a12 801 0:18 7edcf8bbc93b4329 yes > > As you can see, my test machine has a cached mount - the FSC column says 'yes'. > >> When I issue the mount command I find the following lines in dmesg: >> FS-Cache: Loaded >> FS-Cache: Netfs 'nfs' registered for caching > > That just means that the NFS module was loaded and registered itself with > FS-Cache, which doesn't really mean anything. > >> I certainly did not specify the mount option fsc or anything else to >> activate FS-Cache and I could not find any option to avoid it. >> Can someone tell me how to deactivate FS-Cache? > > It isn't necessarily active. If you want to get rid of FS-Cache completely > for NFS, you'll have to build a kernel with: > > CONFIG_NFS_FSCACHE=y > > changed to 'n'. > >> I tried to blacklist the fscache module, but it was used any ways when >> issuing mount. Removing the .ko file resulted in a broken nfs module > > nfs.ko depends on fscache.ko. It wouldn't be able to use it otherwise. > >> Is there a nice way to get rid of FS-Cache or do I have to build my own >> kernel? > > You'll have to build your own kernel. I doubt FS-Cache is the problem. > Unless you activate it by requesting it in a mount option, it won't do > anything. > > You can also check /proc/fs/fscache/stats. > > You can also turn on NFS debugging for FS-Cache to see what it's doing: > > echo $((0x800)) >/proc/sys/sunrpc/nfs_debug > > David > > -- > Linux-cachefs mailing list > Linux-cachefs@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/linux-cachefs -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cachefs
