removing copies from readdir path

daemon/nfs41_daemon.c

@@ -85,7 +85,7 @@ static unsigned int WINAPI thread_main(void *args)
     // buffer used to send downcall content, need to dynamically allocated 
     // as we don't know the length of the buffer (ie. size of directory listing
     unsigned char *inbuf = NULL;
-    DWORD inbuf_len, outbuf_len;
+    DWORD inbuf_len = UPCALL_BUF_SIZE, outbuf_len;
     nfs41_upcall upcall;
 
     pipe = CreateFile(NFS41_USER_DEVICE_NAME_A, GENERIC_READ | GENERIC_WRITE,
@@ -130,11 +130,6 @@ write_downcall:
             "get_last_error=%d\n", upcall.xid, opcode2string(upcall.opcode),
             upcall.status, upcall.last_error);
 
-        if (upcall.opcode == NFS41_DIR_QUERY)
-            inbuf_len = UPCALL_BUF_SIZE + upcall.args.readdir.query_reply_len;
-        else
-            inbuf_len = UPCALL_BUF_SIZE;
-
         inbuf = malloc(inbuf_len);
         if (inbuf == NULL) {
             upcall.status = GetLastError();

daemon/readdir.c

@@ -63,13 +63,15 @@ static int parse_readdir(unsigned char *buffer, uint32_t length, nfs41_upcall *u
     if (status) goto out;
     status = safe_read(&buffer, &length, &args->single, sizeof(args->single));
     if (status) goto out;
+    status = safe_read(&buffer, &length, &args->kbuf, sizeof(args->kbuf));
+    if (status) goto out;
     args->root = upcall->root_ref;
     args->state = upcall->state_ref;
 
     dprintf(1, "parsing NFS41_DIR_QUERY: info_class=%d buf_len=%d "
-        "filter='%s'\n\tInitial\\Restart\\Single %d\\%d\\%d\n",
+        "filter='%s'\n\tInitial\\Restart\\Single %d\\%d\\%d buf=%p\n",
         args->query_class, args->buf_len, args->filter,
-        args->initial, args->restart, args->single);
+        args->initial, args->restart, args->single, args->kbuf);
 out:
     return status;
 }
@@ -479,13 +481,13 @@ static int handle_readdir(nfs41_upcall *upcall)
         goto out;
     }
 
-    entry_buf = malloc(max(args->buf_len, 4096));
+    entry_buf = malloc(args->buf_len);
     if (entry_buf == NULL) {
         status = GetLastError();
         goto out_free_cookie;
     }
 fetch_entries:
-    entry_buf_len = max(args->buf_len, 4096);
+    entry_buf_len = args->buf_len;
 
     init_getattr_request(&attr_request);
     attr_request.arr[0] |= FATTR4_WORD0_RDATTR_ERROR;
@@ -550,20 +552,11 @@ fetch_entries:
 
     if (entry_buf_len) {
         unsigned char *entry_pos = entry_buf;
-        unsigned char *dst_pos;
+        unsigned char *dst_pos = args->kbuf;
         uint32_t dst_len = args->buf_len;
         nfs41_readdir_entry *entry;
         PULONG offset, last_offset = NULL;
 
-        if (args->buf == NULL) {
-            args->buf = malloc(args->buf_len);
-            if (args->buf == NULL) {
-                status = GetLastError();
-                goto out_free_cookie;
-            }
-        }
-        dst_pos = args->buf;
-
         for (;;) {
             entry = (nfs41_readdir_entry*)entry_pos;
             offset = (PULONG)dst_pos; /* ULONG NextEntryOffset */
@@ -625,7 +618,6 @@ out:
             dprintf(1, "error code %d.\n", status);
             break;
         }
-        free(args->buf);
         args->buf = NULL;
     } else {
         dprintf(1, "success!\n");
@@ -642,10 +634,6 @@ static int marshall_readdir(unsigned char *buffer, uint32_t *length, nfs41_upcal
     readdir_upcall_args *args = &upcall->args.readdir;
 
     status = safe_write(&buffer, length, &args->query_reply_len, sizeof(args->query_reply_len));
-    if (status) goto out;
-    status = safe_write(&buffer, length, args->buf, args->query_reply_len);
-out:
-    free(args->buf);
     return status;
 }
 

daemon/upcall.h

@@ -132,6 +132,7 @@ typedef struct __readdir_upcall_args {
     BOOLEAN initial;
     BOOLEAN restart;
     BOOLEAN single;
+    unsigned char *kbuf;
 } readdir_upcall_args;
 
 typedef struct __symlink_upcall_args {

sys/nfs41_driver.c

@@ -186,6 +186,8 @@ typedef struct _updowncall_entry {
             BOOLEAN restart_scan;
             BOOLEAN return_single;
             BOOLEAN initial_query;
+            PMDL mdl;
+            PVOID mdl_buf;
         } QueryFile;
         struct {
             PUNICODE_STRING filename;
@@ -831,7 +833,7 @@ NTSTATUS marshal_nfs41_dirquery(nfs41_updowncall_entry *entry,
     else 
         tmp += *len;
 
-    header_len = *len + 2 * sizeof(ULONG) +
+    header_len = *len + 2 * sizeof(ULONG) + sizeof(HANDLE) +
         length_as_ansi(entry->u.QueryFile.filter) + 3 * sizeof(BOOLEAN);
     if (header_len > buf_len) { 
         status = STATUS_INSUFFICIENT_RESOURCES;
@@ -849,13 +851,34 @@ NTSTATUS marshal_nfs41_dirquery(nfs41_updowncall_entry *entry,
     RtlCopyMemory(tmp, &entry->u.QueryFile.restart_scan, sizeof(BOOLEAN));
     tmp += sizeof(BOOLEAN);
     RtlCopyMemory(tmp, &entry->u.QueryFile.return_single, sizeof(BOOLEAN));
-
+    tmp += sizeof(BOOLEAN);
+    __try {
+        MmProbeAndLockPages(entry->u.QueryFile.mdl, KernelMode, IoModifyAccess);
+        entry->u.QueryFile.mdl_buf = 
+            MmMapLockedPagesSpecifyCache(entry->u.QueryFile.mdl, 
+                UserMode, MmNonCached, NULL, TRUE, NormalPagePriority);
+        if (entry->u.QueryFile.mdl_buf == NULL) {
+            print_error("MmMapLockedPagesSpecifyCache failed to map pages\n");
+            status = STATUS_INSUFFICIENT_RESOURCES;
+            goto out;
+        }
+        DbgP("MdlAddress=%p Userspace=%p\n", entry->u.QueryFile.mdl,
+            entry->u.QueryFile.mdl_buf);
+    } __except(EXCEPTION_EXECUTE_HANDLER) { 
+        NTSTATUS code; 
+        code = GetExceptionCode(); 
+        print_error("Call to MmMapLocked failed due to exception 0x%x\n", code);
+        status = STATUS_ACCESS_DENIED;
+        goto out;
+    }
+    RtlCopyMemory(tmp, &entry->u.QueryFile.mdl_buf, sizeof(HANDLE));
     *len = header_len;
 
-    DbgP("marshal_nfs41_dirquery: filter='%wZ'class=%d "
+    DbgP("marshal_nfs41_dirquery: filter='%wZ'class=%d len=%d "
          "1st\\restart\\single=%d\\%d\\%d\n", entry->u.QueryFile.filter, 
-         entry->u.QueryFile.InfoClass, entry->u.QueryFile.initial_query, 
+         entry->u.QueryFile.InfoClass, entry->u.QueryFile.buf_len, 
-         entry->u.QueryFile.restart_scan, entry->u.QueryFile.return_single);
+         entry->u.QueryFile.initial_query, entry->u.QueryFile.restart_scan, 
+         entry->u.QueryFile.return_single);
 out:
     DbgEx();
     return status;
@@ -1568,6 +1591,26 @@ nfs41_downcall (
                 cur->open_state, cur->u.Open.mode, cur->u.Open.changeattr);
             break;
         case NFS41_DIR_QUERY:
+            RtlCopyMemory(&tmp->u.QueryFile.buf_len, buf, sizeof(ULONG));
+            DbgP("readdir reply size %d\n", tmp->u.QueryFile.buf_len);
+            buf += sizeof(ULONG);
+            __try {
+                MmUnmapLockedPages(cur->u.QueryFile.mdl_buf, cur->u.QueryFile.mdl);
+                MmUnlockPages(cur->u.QueryFile.mdl);
+            } __except(EXCEPTION_EXECUTE_HANDLER) { 
+                NTSTATUS code; 
+                code = GetExceptionCode(); 
+                print_error("Call to MmUnmapLockedPages failed due to"
+                    " exception 0x%0x\n", code);
+                status = STATUS_ACCESS_DENIED;
+            }
+            if (tmp->u.QueryFile.buf_len > cur->u.QueryFile.buf_len) {
+                cur->status = STATUS_BUFFER_TOO_SMALL;
+                cur->u.QueryFile.buf_len = tmp->u.QueryFile.buf_len;
+                break;
+            }
+            cur->u.QueryFile.buf_len = tmp->u.QueryFile.buf_len;
+            break;
         case NFS41_FILE_QUERY:
             RtlCopyMemory(&tmp->u.QueryFile.buf_len, buf, sizeof(ULONG));
             buf += sizeof(ULONG);
@@ -3428,6 +3471,14 @@ NTSTATUS nfs41_QueryDirectory (
     entry->u.QueryFile.InfoClass = InfoClass;
     entry->u.QueryFile.buf_len = RxContext->Info.LengthRemaining;
     entry->u.QueryFile.buf = RxContext->Info.Buffer;
+    entry->u.QueryFile.mdl = IoAllocateMdl(RxContext->Info.Buffer, 
+        RxContext->Info.LengthRemaining, FALSE, FALSE, NULL);
+    if (entry->u.QueryFile.mdl == NULL) {
+        status = STATUS_INTERNAL_ERROR;
+        RxFreePool(entry);
+        goto out;
+    }
+
     entry->u.QueryFile.filter = Filter;
     entry->u.QueryFile.initial_query = RxContext->QueryDirectory.InitialQuery;
     entry->u.QueryFile.restart_scan = RxContext->QueryDirectory.RestartScan;
@@ -3454,6 +3505,7 @@ NTSTATUS nfs41_QueryDirectory (
         /* map windows ERRORs to NTSTATUS */
         status = map_querydir_errors(entry->status);
     }
+    IoFreeMdl(entry->u.QueryFile.mdl);
     RxFreePool(entry);
 out:
 #ifdef ENABLE_TIMINGS