03/05: [SETUPLIB] Lock the BTRFS volume before installing the new bootsector code.

[Hermès Bélusca-Maïto]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=f527e23aa75e8ae3fa87b…

commit f527e23aa75e8ae3fa87b075f205513a35789403
Author:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
AuthorDate: Sun Nov 11 20:31:35 2018 +0100
Commit:     Hermès Bélusca-Maïto <hermes.belusca-maito(a)reactos.org>
CommitDate: Sun Nov 11 21:55:48 2018 +0100

    [SETUPLIB] Lock the BTRFS volume before installing the new bootsector code.
    
    CORE-15334 CORE-15339
    
    The BTRFS driver requires the volume to be locked in order to modify
    the first sectors of the partition, even though they are outside the
    file-system space / in the reserved area (they are situated before
    the super-block at 0x1000) and is in principle allowed by the NT
    storage stack.
    So we lock here in order to write the bootsector at sector 0.
    If locking fails, we ignore and continue nonetheless.
    
    See also the following links for reference:
    https://stackoverflow.com/a/12928934
    https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-wri…
   
https://support.microsoft.com/en-us/help/942448/changes-to-the-file-system-…
---
 base/setup/lib/bootsup.c | 58 +++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 48 insertions(+), 10 deletions(-)

diff --git a/base/setup/lib/bootsup.c b/base/setup/lib/bootsup.c
index 2459c731da..3d494c949a 100644
--- a/base/setup/lib/bootsup.c
+++ b/base/setup/lib/bootsup.c
@@ -1613,6 +1613,7 @@ InstallBtrfsBootCodeToDisk(
     IN PCWSTR RootPath)
 {
     NTSTATUS Status;
+    NTSTATUS LockStatus;
     UNICODE_STRING Name;
     OBJECT_ATTRIBUTES ObjectAttributes;
     IO_STATUS_BLOCK IoStatusBlock;
@@ -1754,6 +1755,30 @@ InstallBtrfsBootCodeToDisk(
         return Status;
     }
 
+    /*
+     * The BTRFS driver requires the volume to be locked in order to modify
+     * the first sectors of the partition, even though they are outside the
+     * file-system space / in the reserved area (they are situated before
+     * the super-block at 0x1000) and is in principle allowed by the NT
+     * storage stack.
+     * So we lock here in order to write the bootsector at sector 0.
+     * If locking fails, we ignore and continue nonetheless.
+     */
+    LockStatus = NtFsControlFile(FileHandle,
+                                 NULL,
+                                 NULL,
+                                 NULL,
+                                 &IoStatusBlock,
+                                 FSCTL_LOCK_VOLUME,
+                                 NULL,
+                                 0,
+                                 NULL,
+                                 0);
+    if (!NT_SUCCESS(LockStatus))
+    {
+        DPRINT1("WARNING: Failed to lock BTRFS volume for writing bootsector!
Operations may fail! (Status 0x%lx)\n", LockStatus);
+    }
+
     /* Obtaining partition info and writing it to bootsector */
     Status = NtDeviceIoControlFile(FileHandle,
                                    NULL,
@@ -1768,9 +1793,7 @@ InstallBtrfsBootCodeToDisk(
     if (!NT_SUCCESS(Status))
     {
         DPRINT1("IOCTL_DISK_GET_PARTITION_INFO_EX failed (Status %lx)\n",
Status);
-        NtClose(FileHandle);
-        RtlFreeHeap(ProcessHeap, 0, NewBootSector);
-        return Status;
+        goto Quit;
     }
 
     /* Write new bootsector to RootPath */
@@ -1788,15 +1811,13 @@ InstallBtrfsBootCodeToDisk(
                          sizeof(BTRFS_BOOTSECTOR),
                          &FileOffset,
                          NULL);
-#if 0
     if (!NT_SUCCESS(Status))
     {
         DPRINT1("NtWriteFile() failed (Status %lx)\n", Status);
-        NtClose(FileHandle);
-        RtlFreeHeap(ProcessHeap, 0, NewBootSector);
-        return Status;
+        goto Quit;
     }
 
+#if 0
     /* Write backup boot sector */
     if ((BackupBootSector != 0x0000) && (BackupBootSector != 0xFFFF))
     {
@@ -1813,9 +1834,7 @@ InstallBtrfsBootCodeToDisk(
         if (!NT_SUCCESS(Status))
         {
             DPRINT1("NtWriteFile() failed (Status %lx)\n", Status);
-            NtClose(FileHandle);
-            RtlFreeHeap(ProcessHeap, 0, NewBootSector);
-            return Status;
+            goto Quit;
         }
     }
 
@@ -1835,6 +1854,25 @@ InstallBtrfsBootCodeToDisk(
         DPRINT1("NtWriteFile() failed (Status %lx)\n", Status);
     }
 #endif
+
+Quit:
+    /* Unlock the volume */
+    LockStatus = NtFsControlFile(FileHandle,
+                                 NULL,
+                                 NULL,
+                                 NULL,
+                                 &IoStatusBlock,
+                                 FSCTL_UNLOCK_VOLUME,
+                                 NULL,
+                                 0,
+                                 NULL,
+                                 0);
+    if (!NT_SUCCESS(LockStatus))
+    {
+        DPRINT1("Failed to unlock BTRFS volume (Status 0x%lx)\n", LockStatus);
+    }
+
+    /* Close the volume */
     NtClose(FileHandle);
 
     /* Free the new boot sector */