+ struct lu_env *env;
+ struct cl_io *io;
+ struct vvp_io *vio;
+ struct cl_env_nest nest;
+ int result;
+ sigset_t set;
+ struct inode *inode;
+ struct ll_inode_info *lli;
+ ENTRY;
+
+ LASSERT(vmpage != NULL);
+
+ io = ll_fault_io_init(vma, &env, &nest, vmpage->index, NULL);
+ if (IS_ERR(io))
+ GOTO(out, result = PTR_ERR(io));
+
+ result = io->ci_result;
+ if (result < 0)
+ GOTO(out_io, result);
+
+ io->u.ci_fault.ft_mkwrite = 1;
+ io->u.ci_fault.ft_writable = 1;
+
+ vio = vvp_env_io(env);
+ vio->u.fault.ft_vma = vma;
+ vio->u.fault.ft_vmpage = vmpage;
+
+ set = cfs_block_sigsinv(sigmask(SIGKILL) | sigmask(SIGTERM));
+
+ /* we grab lli_trunc_sem to exclude truncate case.
+ * Otherwise, we could add dirty pages into osc cache
+ * while truncate is on-going. */
+ inode = vvp_object_inode(io->ci_obj);
+ lli = ll_i2info(inode);
+ down_read(&lli->lli_trunc_sem);
+
+ result = cl_io_loop(env, io);
+
+ up_read(&lli->lli_trunc_sem);
+
+ cfs_restore_sigs(set);
+
+ if (result == 0) {
+ lock_page(vmpage);
+ if (vmpage->mapping == NULL) {
+ unlock_page(vmpage);
+
+ /* page was truncated and lock was cancelled, return
+ * ENODATA so that VM_FAULT_NOPAGE will be returned
+ * to handle_mm_fault(). */
+ if (result == 0)
+ result = -ENODATA;
+ } else if (!PageDirty(vmpage)) {
+ /* race, the page has been cleaned by ptlrpcd after
+ * it was unlocked, it has to be added into dirty
+ * cache again otherwise this soon-to-dirty page won't
+ * consume any grants, even worse if this page is being
+ * transferred because it will break RPC checksum.
+ */
+ unlock_page(vmpage);
+
+ CDEBUG(D_MMAP, "Race on page_mkwrite %p/%lu, page has "
+ "been written out, retry.\n",
+ vmpage, vmpage->index);
+
+ *retry = true;
+ result = -EAGAIN;
+ }