Changeset 57020 in vbox for trunk

Timestamp:

Jul 20, 2015 1:06:56 PM (9 years ago)

Author:

vboxsync

Message:

direnum-r3-nt.cpp: Workaround for windows CIFS servers with directories containing lots of files, they don't like large buffers (limit seems to be 64KB).

File:

• trunk/src/VBox/Runtime/r3/nt/direnum-r3-nt.cpp (modified) (2 diffs)

trunk/src/VBox/Runtime/r3/nt/direnum-r3-nt.cpp

@@ -313 +313 @@
     {
         /*
-         * The first time around we have figure which info class we can use.
-         * We prefer one which gives us file IDs, but we'll settle for less.
+         * The first time around we have to figure which info class we can use
+         * as well as the right buffer size.  We prefer an info class which
+         * gives us file IDs (Vista+ IIRC) and we prefer large buffers (for long
+         * ReFS file names and such), but we'll settle for whatever works...
+         *
+         * The windows 7 thru 8.1 CIFS servers have been observed to have
+         * trouble with large buffers, but weirdly only when listing large
+         * directories.  Seems 0x10000 is the max.  (Samba does not exhibit
+         * these problems, of course.)
+         *
+         * This complicates things.  The buffer size issues causes an
+         * STATUS_INVALID_PARAMETER error.  Now, you would expect the lack of
+         * FileIdBothDirectoryInformation support to return
+         * STATUS_INVALID_INFO_CLASS, but I'm not entirely sure if we can 100%
+         * depend on third IFSs to get that right.  Nor, am I entirely confident
+         * that we can depend on them to check the class before the buffer size.
+         *
+         * Thus the mess.
          */
         pThis->enmInfoClass = FileIdBothDirectoryInformation;
@@ -328 +344 @@
                                     pThis->pNtFilterStr,
                                     FALSE /*RestartScan */);
-        if (!NT_SUCCESS(rcNt))
+        if (NT_SUCCESS(rcNt))
+        { /* likely */ }
+        else
         {
-            pThis->enmInfoClass = FileBothDirectoryInformation;
-            rcNt = NtQueryDirectoryFile(pThis->hDir,
-                                        NULL /* Event */,
-                                        NULL /* ApcRoutine */,
-                                        NULL /* ApcContext */,
-                                        &Ios,
-                                        pThis->pabBuffer,
-                                        pThis->cbBufferAlloc,
-                                        pThis->enmInfoClass,
-                                        RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
-                                        pThis->pNtFilterStr,
-                                        FALSE /*RestartScan */);
+            for (unsigned iRetry = 0; iRetry < 2; iRetry++)
+            {
+                if (   rcNt == STATUS_INVALID_INFO_CLASS
+                    || rcNt == STATUS_INVALID_PARAMETER_8
+                    || iRetry != 0)
+                    pThis->enmInfoClass = FileBothDirectoryInformation;
+
+                uint32_t cbBuffer = pThis->cbBufferAlloc;
+                if (   rcNt == STATUS_INVALID_PARAMETER
+                    || rcNt == STATUS_INVALID_PARAMETER_7
+                    || iRetry != 0)
+                    cbBuffer = RT_MIN(cbBuffer / 2, 0x10000);
+
+                for (;;)
+                {
+                    rcNt = NtQueryDirectoryFile(pThis->hDir,
+                                                NULL /* Event */,
+                                                NULL /* ApcRoutine */,
+                                                NULL /* ApcContext */,
+                                                &Ios,
+                                                pThis->pabBuffer,
+                                                cbBuffer,
+                                                pThis->enmInfoClass,
+                                                RTDIR_NT_SINGLE_RECORD /*ReturnSingleEntry */,
+                                                pThis->pNtFilterStr,
+                                                FALSE /*RestartScan */);
+                    if (   NT_SUCCESS(rcNt)
+                        || cbBuffer == pThis->cbBufferAlloc
+                        || cbBuffer <= sizeof(*pThis->uCurData.pBothId) + sizeof(WCHAR) * 260)
+                        break;
+
+                    /* Reduce the buffer size agressivly and try again.  We fall back to
+                       FindFirstFile values for the final lap.  This means we'll do 4 rounds
+                       with the current initial buffer size (64KB, 8KB, 1KB, 0x278/0x268). */
+                    cbBuffer /= 8;
+                    if (cbBuffer < 1024)
+                        cbBuffer = pThis->enmInfoClass == FileIdBothDirectoryInformation
+                                 ? sizeof(*pThis->uCurData.pBothId) + sizeof(WCHAR) * 260
+                                 : sizeof(*pThis->uCurData.pBoth)   + sizeof(WCHAR) * 260;
+                }
+                if (NT_SUCCESS(rcNt))
+                {
+                    pThis->cbBufferAlloc = cbBuffer;
+                    break;
+                }
+            }
         }
     }