Re: [PATCH] mount.nfs: try the next address after mount fails with ETIMEDOUT

[Steve Dickson <SteveD@redhat.com>]

On 05/31/2012 09:03 AM, Jeff Layton wrote:
> If a NFS mount attempt fails with an ETIMEDOUT error, the mount.nfs code
> doesn't currently attempt the next address in the list. For a NFSv4 mount
> the initial mount() call almost always ends up going over
> NFS_DEF_FG_TIMEOUT_MINUTES and the mount is never retried.
> 
> For a v3 mount, it ends up continually retrying against the same IPv6
> address, and never tries the IPv4 address. Eventually it gives up once
> it hits the NFS_DEF_FG_TIMEOUT_MINUTES timeout.
> 
> It's possible that a server is just unreachable via IPv6 (due to a
> routing misconfiguration for instance), or is dropping IPv6 frames on
> the floor. In that situation, it might still be reachable via IPv4 and
> trying the next address could have allowed the mount to succeed.
> 
> Fix this by treating ETIMEDOUT in a similar fashion to ECONNREFUSED.
> Have the client try the next address in the list before giving up and
> returning an error.
> 
> Our QA folks noticed this after a routing problem in one of our test
> labs. I was able to reproduce it by having the server drop incoming
> IPv6 frames from the client's address.
> 
> With this patch, the mount eventually succeeds over IPv4 instead of
> returning an error.
> 
> Cc: Chuck Lever <chuck.lever@oracle.com>
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
Committed...

steved.

> ---
>  utils/mount/stropts.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/utils/mount/stropts.c b/utils/mount/stropts.c
> index e09aa7c..0aa9a75 100644
> --- a/utils/mount/stropts.c
> +++ b/utils/mount/stropts.c
> @@ -665,6 +665,7 @@ static int nfs_try_mount_v3v2(struct nfsmount_info *mi)
>  		case ECONNREFUSED:
>  		case EOPNOTSUPP:
>  		case EHOSTUNREACH:
> +		case ETIMEDOUT:
>  			continue;
>  		default:
>  			goto out;
> @@ -752,6 +753,7 @@ static int nfs_try_mount_v4(struct nfsmount_info *mi)
>  		switch (errno) {
>  		case ECONNREFUSED:
>  		case EHOSTUNREACH:
> +		case ETIMEDOUT:
>  			continue;
>  		default:
>  			goto out;