• Robert Milkowski's avatar
    NFSv4.0: nfs4_do_fsinfo() should not do implicit lease renewals · 7dc2993a
    Robert Milkowski authored
    Currently, each time nfs4_do_fsinfo() is called it will do an implicit
    NFS4 lease renewal, which is not compliant with the NFS4 specification.
    This can result in a lease being expired by an NFS server.
    
    Commit 83ca7f5a ("NFS: Avoid PUTROOTFH when managing leases")
    introduced implicit client lease renewal in nfs4_do_fsinfo(),
    which can result in the NFSv4.0 lease to expire on a server side,
    and servers returning NFS4ERR_EXPIRED or NFS4ERR_STALE_CLIENTID.
    
    This can easily be reproduced by frequently unmounting a sub-mount,
    then stat'ing it to get it mounted again, which will delay or even
    completely prevent client from sending RENEW operations if no other
    NFS operations are issued. Eventually nfs server will expire client's
    lease and return an error on file access or next RENEW.
    
    This can also happen when a sub-mount is automatically unmounted
    due to inactivity (after nfs_mountpoint_expiry_timeout), then it is
    mounted again via stat(). This can result in a short window during
    which client's lease will expire on a server but not on a client.
    This specific case was observed on production systems.
    
    This patch removes the implicit lease renewal from nfs4_do_fsinfo().
    
    Fixes: 83ca7f5a ("NFS: Avoid PUTROOTFH when managing leases")
    Signed-off-by: default avatarRobert Milkowski <rmilkowski@gmail.com>
    Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
    7dc2993a
nfs4renewd.c 4.54 KB