nfs: don't allow reexport reclaims

In the reexport case, nfsd is currently passing along locks with the
reclaim bit set.  The client sends a new lock request, which is granted
if there's currently no conflict--even if it's possible a conflicting
lock could have been briefly held in the interim.

We don't currently have any way to safely grant reclaim, so for now
let's just deny them all.

I'm doing this by passing the reclaim bit to nfs and letting it fail the
call, with the idea that eventually the client might be able to do
something more forgiving here.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 1fef107..7411658 100644 (file)
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -806,6 +806,9 @@ int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
 
        nfs_inc_stats(inode, NFSIOS_VFSLOCK);
 
+       if (fl->fl_flags & FL_RECLAIM)
+               return -ENOGRACE;
+
        /* No mandatory locks over NFS */
        if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
                goto out_err;

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index d0b2041..1b6a7f4 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6903,6 +6903,9 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
        if (!locks_in_grace(net) && lock->lk_reclaim)
                goto out;
 
+       if (lock->lk_reclaim)
+               fl_flags |= FL_RECLAIM;
+
        fp = lock_stp->st_stid.sc_file;
        switch (lock->lk_type) {
                case NFS4_READW_LT:

diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c
index 60d7c59..90fcd61 100644 (file)
--- a/fs/nfsd/nfsproc.c
+++ b/fs/nfsd/nfsproc.c
@@ -881,6 +881,7 @@ nfserrno (int errno)
                { nfserr_serverfault, -ENFILE },
                { nfserr_io, -EUCLEAN },
                { nfserr_perm, -ENOKEY },
+               { nfserr_no_grace, -ENOGRACE},
        };
        int     i;
 

diff --git a/include/linux/errno.h b/include/linux/errno.h
index d73f597..8b0c754 100644 (file)
--- a/include/linux/errno.h
+++ b/include/linux/errno.h
@@ -31,5 +31,6 @@
 #define EJUKEBOX       528     /* Request initiated, but will not complete before timeout */
 #define EIOCBQUEUED    529     /* iocb queued, will get completion event */
 #define ERECALLCONFLICT        530     /* conflict with recalled state */
+#define ENOGRACE       531     /* NFS file lock reclaim refused */
 
 #endif

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6405742..1f5c3db 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -997,6 +997,7 @@ static inline struct file *get_file(struct file *f)
 #define FL_UNLOCK_PENDING      512 /* Lease is being broken */
 #define FL_OFDLCK      1024    /* lock is "owned" by struct file */
 #define FL_LAYOUT      2048    /* outstanding pNFS layout */
+#define FL_RECLAIM     4096    /* reclaiming from a reboot server */
 
 #define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE)