nfsd: use locks_inode_context helper

nfsd currently doesn't access i_flctx safely everywhere. This requires a
smp_load_acquire, as the pointer is set via cmpxchg (a release
operation).

Acked-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>

fs/nfsd/nfs4state.c

@@ -4758,7 +4758,7 @@ nfs4_share_conflict(struct svc_fh *current_fh, unsigned int deny_type)
 
 static bool nfsd4_deleg_present(const struct inode *inode)
 {
-	struct file_lock_context *ctx = smp_load_acquire(&inode->i_flctx);
+	struct file_lock_context *ctx = locks_inode_context(inode);
 
 	return ctx && !list_empty_careful(&ctx->flc_lease);
 }
@@ -5897,7 +5897,7 @@ nfs4_lockowner_has_blockers(struct nfs4_lockowner *lo)
 
 	list_for_each_entry(stp, &lo->lo_owner.so_stateids, st_perstateowner) {
 		nf = stp->st_stid.sc_file;
-		ctx = nf->fi_inode->i_flctx;
+		ctx = locks_inode_context(nf->fi_inode);
 		if (!ctx)
 			continue;
 		if (locks_owner_has_blockers(ctx, lo))
@@ -7713,7 +7713,7 @@ check_for_locks(struct nfs4_file *fp, struct nfs4_lockowner *lowner)
 	}
 
 	inode = locks_inode(nf->nf_file);
-	flctx = inode->i_flctx;
+	flctx = locks_inode_context(inode);
 
 	if (flctx && !list_empty_careful(&flctx->flc_posix)) {
 		spin_lock(&flctx->flc_lock);