| Message ID | 172800404387.1692160.2013457390996721241@noble.neil.brown.name (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | NFSv3: only use NFS timeout for MOUNT when protocols are compatible | expand |
On Fri, 04 Oct 2024, NeilBrown wrote: > If a timeout is specified in the mount options, it currently applies to > both the NFS protocol and (with v3) the MOUNT protocol. This is > sensible when they both use the same underlying protocol, or those > protocols are compatible w.r.t timeouts as RDMA and TCP are. > > However if, for example, NFS is using TCP and MOUNT is using UDP then > using the same timeout doesn't make much sense. > > If you > mount -o vers=3,proto=tcp,mountproto=udp,timeo=600,retrans=5 \ > server:/path /mountpoint > > then the timeo=600 which was intended for the NFS/TCP request will > apply to the MOUNT/UDP requests with the result that there will only be > one request sent (because UDP has a maximum timeout of 60 seconds). > This is not what a reasonable person might expect. > > This patch disables the sharing of timeout information in cases where > the underlying protocols are not compatible. > > Fixes: c9301cb35b59 ("nfs: hornor timeo and retrans option when mounting NFSv3") > Signed-off-by: NeilBrown <neilb@suse.de> > --- > fs/nfs/super.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/fs/nfs/super.c b/fs/nfs/super.c > index 9723b6c53397..ae5c5e39afa0 100644 > --- a/fs/nfs/super.c > +++ b/fs/nfs/super.c > @@ -885,7 +885,15 @@ static int nfs_request_mount(struct fs_context *fc, > * Now ask the mount server to map our export path > * to a file handle. > */ > - status = nfs_mount(&request, ctx->timeo, ctx->retrans); > + if ((request.protocol == XPRT_TRANSPORT_UDP) == > + !(ctx->flags & NFS_MOUNT_TCP)) > + /* > + * NFS protocol and mount protocol are both UDP or neither UDP > + * so timeouts are compatible. Use NFS timeouts for MOUNT > + */ > + status = nfs_mount(&request, ctx->timeo, ctx->retrans); > + else > + status = nfs_mount(&request, NFS_UNSPEC_TIMEO, NFS_UNSPEC_RETRANS); > if (status != 0) { > dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n", > request.hostname, status); > -- > 2.46.0 > > > Anna, Trond: have you had a chance to look at this yet? Thanks, NeilBrown
diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 9723b6c53397..ae5c5e39afa0 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -885,7 +885,15 @@ static int nfs_request_mount(struct fs_context *fc, * Now ask the mount server to map our export path * to a file handle. */ - status = nfs_mount(&request, ctx->timeo, ctx->retrans); + if ((request.protocol == XPRT_TRANSPORT_UDP) == + !(ctx->flags & NFS_MOUNT_TCP)) + /* + * NFS protocol and mount protocol are both UDP or neither UDP + * so timeouts are compatible. Use NFS timeouts for MOUNT + */ + status = nfs_mount(&request, ctx->timeo, ctx->retrans); + else + status = nfs_mount(&request, NFS_UNSPEC_TIMEO, NFS_UNSPEC_RETRANS); if (status != 0) { dfprintk(MOUNT, "NFS: unable to mount server %s, error %d\n", request.hostname, status);
If a timeout is specified in the mount options, it currently applies to both the NFS protocol and (with v3) the MOUNT protocol. This is sensible when they both use the same underlying protocol, or those protocols are compatible w.r.t timeouts as RDMA and TCP are. However if, for example, NFS is using TCP and MOUNT is using UDP then using the same timeout doesn't make much sense. If you mount -o vers=3,proto=tcp,mountproto=udp,timeo=600,retrans=5 \ server:/path /mountpoint then the timeo=600 which was intended for the NFS/TCP request will apply to the MOUNT/UDP requests with the result that there will only be one request sent (because UDP has a maximum timeout of 60 seconds). This is not what a reasonable person might expect. This patch disables the sharing of timeout information in cases where the underlying protocols are not compatible. Fixes: c9301cb35b59 ("nfs: hornor timeo and retrans option when mounting NFSv3") Signed-off-by: NeilBrown <neilb@suse.de> --- fs/nfs/super.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)