locks: allow {vfs,posix}_lock_file to return conflicting lock

The nfsv4 protocol's lock operation, in the case of a conflict, returns
information about the conflicting lock.

It's unclear how clients can use this, so for now we're not going so far as to
add a filesystem method that can return a conflicting lock, but we may as well
return something in the local case when it's easy to.

Signed-off-by: Marc Eshel <eshel@almaden.ibm.com>
Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>

1 files changed, 6 insertions, 4 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index e42c7a0eb6fa..03b0578781cb 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2657,6 +2657,7 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         struct file_lock conflock;
         __be32 status = 0;
         unsigned int strhashval;
+        unsigned int cmd;
         int err;
 
         dprintk("NFSD: nfsd4_lock: start=%Ld length=%Ld\n",
@@ -2739,10 +2740,12 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
                 case NFS4_READ_LT:
                 case NFS4_READW_LT:
                         file_lock.fl_type = F_RDLCK;
+                        cmd = F_SETLK;
                 break;
                 case NFS4_WRITE_LT:
                 case NFS4_WRITEW_LT:
                         file_lock.fl_type = F_WRLCK;
+                        cmd = F_SETLK;
                 break;
                 default:
                         status = nfserr_inval;
@@ -2769,9 +2772,8 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 
         /* XXX?: Just to divert the locks_release_private at the start of
          * locks_copy_lock: */
-        conflock.fl_ops = NULL;
-        conflock.fl_lmops = NULL;
-        err = posix_lock_file_conf(filp, &file_lock, &conflock);
+        locks_init_lock(&conflock);
+        err = posix_lock_file(filp, &file_lock, &conflock);
         switch (-err) {
         case 0: /* success! */
                 update_stateid(&lock_stp->st_stateid);
@@ -2933,7 +2935,7 @@ nfsd4_locku(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
         /*
         *  Try to unlock the file in the VFS.
         */
-        err = posix_lock_file(filp, &file_lock);
+        err = posix_lock_file(filp, &file_lock, NULL);
         if (err) {
                 dprintk("NFSD: nfs4_locku: posix_lock_file failed!\n");
                 goto out_nfserr;