NTFS: Some utilities modify the boot sector but do not update the checksum.

      Thus, relax the checking in fs/ntfs/super.c::is_boot_sector_ntfs() to
      only emit a warning when the checksum is incorrect rather than
      refusing the mount.  Thanks to Bernd Casimir for pointing this
      problem out.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

2 files changed, 13 insertions, 4 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 51428bfce952..8ff6ea778fbd 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -105,6 +105,11 @@ ToDo/Notes:
           non-resident by a concurrent file write.
         - Remove checks for NULL before calling kfree() since kfree() does the
           checking itself.  (Jesper Juhl)
+        - Some utilities modify the boot sector but do not update the checksum.
+          Thus, relax the checking in fs/ntfs/super.c::is_boot_sector_ntfs() to
+          only emit a warning when the checksum is incorrect rather than
+          refusing the mount.  Thanks to Bernd Casimir for pointing this
+          problem out.
 
 2.1.22 - Many bug and race fixes and error handling improvements.
 
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 25fa1d1668da..6f752ea765c3 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -38,6 +38,7 @@
 #include "debug.h"
 #include "index.h"
 #include "aops.h"
+#include "layout.h"
 #include "malloc.h"
 #include "ntfs.h"
 
@@ -532,16 +533,19 @@ static BOOL is_boot_sector_ntfs(const struct super_block *sb,
 {
         /*
          * Check that checksum == sum of u32 values from b to the checksum
-         * field. If checksum is zero, no checking is done.
+         * field.  If checksum is zero, no checking is done.  We will work when
+         * the checksum test fails, since some utilities update the boot sector
+         * ignoring the checksum which leaves the checksum out-of-date.  We
+         * report a warning if this is the case.
          */
-        if ((void*)b < (void*)&b->checksum && b->checksum) {
+        if ((void*)b < (void*)&b->checksum && b->checksum && !silent) {
                 le32 *u;
                 u32 i;
 
                 for (i = 0, u = (le32*)b; u < (le32*)(&b->checksum); ++u)
                         i += le32_to_cpup(u);
                 if (le32_to_cpu(b->checksum) != i)
-                        goto not_ntfs;
+                        ntfs_warning(sb, "Invalid boot sector checksum.");
         }
         /* Check OEMidentifier is "NTFS    " */
         if (b->oem_id != magicNTFS)
@@ -591,7 +595,7 @@ static BOOL is_boot_sector_ntfs(const struct super_block *sb,
          * many BIOSes will refuse to boot from a bootsector if the magic is
          * incorrect, so we emit a warning.
          */
-        if (!silent && b->end_of_sector_marker != cpu_to_le16(0xaa55))
+        if (!silent && b->end_of_sector_marker != const_cpu_to_le16(0xaa55))
                 ntfs_warning(sb, "Invalid end of sector marker.");
         return TRUE;
 not_ntfs: