NTFS: 2.1.8 release - If the $LogFile indicates a clean shutdown and a

      read-write (re)mount is requested, empty $LogFile by overwriting it
      with 0xff bytes to ensure that Windows cannot cause data corruption
      by replaying a stale journal after Linux has written to the volume.

Documentation/filesystems/ntfs.txt

@@ -273,6 +273,18 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.1.8:
+	- Read the $MFT mirror and compare it to the $MFT and if the two do not
+	  match, force a read-only mount and do not allow read-write remounts.
+	- Read and parse the $LogFile journal and if it indicates that the
+	  volume was not shutdown cleanly, force a read-only mount and do not
+	  allow read-write remounts.  If the $LogFile indicates a clean
+	  shutdown and a read-write (re)mount is requested, empty $LogFile to
+	  ensure that Windows cannot cause data corruption by replaying a stale
+	  journal after Linux has written to the volume.
+	- Improve time handling so that the NTFS time is fully preserved when
+	  converted to kernel time and only up to 99 nano-seconds are lost when
+	  kernel time is converted to NTFS time.
 2.1.7:
 	- Enable NFS exporting of mounted NTFS volumes.
 2.1.6:

fs/ntfs/ChangeLog

@@ -19,7 +19,7 @@ ToDo:
 	  sufficient for synchronisation here. We then just need to make sure
 	  ntfs_readpage/writepage/truncate interoperate properly with us.
 
-2.1.8-WIP
+2.1.8 - Handle $MFT mirror and $LogFile, improve time ihandling, and cleanups.
 
 	- Use get_bh() instead of manual atomic_inc() in fs/ntfs/compress.c.
 	- Modify fs/ntfs/time.c::ntfs2utc(), get_current_ntfs_time(), and
@@ -52,6 +52,10 @@ ToDo:
 	  think that a volume is dirty when in fact it is clean.  This should
 	  only affect volumes that have not been shutdown cleanly and did not
 	  have any pending, non-check-pointed i/o.
+	- If the $LogFile indicates a clean shutdown and a read-write (re)mount
+	  is requested, empty $LogFile by overwriting it with 0xff bytes to
+	  ensure that Windows cannot cause data corruption by replaying a stale
+	  journal after Linux has written to the volume.
 
 2.1.7 - Enable NFS exporting of mounted NTFS volumes.
 

fs/ntfs/Makefile

@@ -5,7 +5,7 @@ obj-$(CONFIG_NTFS_FS) += ntfs.o
 ntfs-objs := aops.o attrib.o compress.o debug.o dir.o file.o inode.o logfile.o \
 	     mft.o mst.o namei.o super.o sysctl.o unistr.o upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.8-WIP\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.8\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG

fs/ntfs/logfile.c

@@ -662,4 +662,76 @@ BOOL ntfs_is_logfile_clean(struct inode *log_vi)
 	return FALSE;
 }
 
+/**
+ * ntfs_empty_logfile - empty the contents of the $LogFile journal
+ * @log_vi:	struct inode of loaded journal $LogFile to empty
+ *
+ * Empty the contents of the $LogFile journal @log_vi and return TRUE on
+ * success FALSE on error.
+ *
+ * This function assumes that the $LogFile journal has already been consistency
+ * checked by a call to ntfs_check_logfile() and that ntfs_is_logfile_clean()
+ * has been used to ensure that the $LogFile is clean.
+ */
+BOOL ntfs_empty_logfile(struct inode *log_vi)
+{
+	ntfs_volume *vol = NTFS_SB(log_vi->i_sb);
+	struct address_space *mapping;
+	pgoff_t idx, end;
+
+	ntfs_debug("Entering.");
+	if (NVolLogFileEmpty(vol))
+		goto done;
+	mapping = log_vi->i_mapping;
+	end = (log_vi->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	for (idx = 0; idx < end; ++idx) {
+		struct page *page;
+		u8 *kaddr;
+
+		/* Find or create the current page.  (The page is locked.) */
+		page = grab_cache_page(mapping, idx);
+		if (unlikely(!page)) {
+			ntfs_error(vol->sb, "Insufficient memory to grab "
+					"$LogFile page (index %lu).", idx);
+			return FALSE;
+		}
+		/*
+		 * Set all bytes in the page to 0xff.  It doesn't matter if we
+		 * go beyond i_size, because ntfs_writepage() will take care of
+		 * that for us.
+		 */
+		kaddr = (u8*)kmap_atomic(page, KM_USER0);
+		memset(kaddr, 0xff, PAGE_CACHE_SIZE);
+		flush_dcache_page(page);
+		kunmap_atomic(kaddr, KM_USER0);
+		/*
+		 * If the page has buffers, mark them uptodate since buffer
+		 * state and not page state is definitive in 2.6 kernels.
+		 */
+		if (page_has_buffers(page)) {
+			struct buffer_head *bh, *head;
+
+			bh = head = page_buffers(page);
+			do {
+				set_buffer_uptodate(bh);
+			} while ((bh = bh->b_this_page) != head);
+		}
+		/* Now that buffers are uptodate, set the page uptodate, too. */
+		SetPageUptodate(page);
+		/*
+		 * Set the page and all its buffers dirty and mark the inode
+		 * dirty, too. The VM will write the page later on.
+		 */
+		set_page_dirty(page);
+		/* Finally unlock and release the page. */
+		unlock_page(page);
+		page_cache_release(page);
+	}
+	/* We set the flag so we do not clear the log file again on remount. */
+	NVolSetLogFileEmpty(vol);
+done:
+	ntfs_debug("Done.");
+	return TRUE;
+}
+
 #endif /* NTFS_RW */

fs/ntfs/logfile.h

@@ -298,6 +298,8 @@ extern BOOL ntfs_check_logfile(struct inode *log_vi);
 
 extern BOOL ntfs_is_logfile_clean(struct inode *log_vi);
 
+extern BOOL ntfs_empty_logfile(struct inode *log_vi);
+
 #endif /* NTFS_RW */
 
 #endif /* _LINUX_NTFS_LOGFILE_H */

fs/ntfs/super.c

@@ -299,7 +299,7 @@ static BOOL parse_options(ntfs_volume *vol, char *opt)
  *
  * Change the mount options of an already mounted ntfs filesystem.
  *
- * NOTE: The VFS set the @sb->s_flags remount flags to @flags after
+ * NOTE:  The VFS sets the @sb->s_flags remount flags to @flags after
  * ntfs_remount() returns successfully (i.e. returns 0).  Otherwise,
  * @sb->s_flags are not changed.
  */
@@ -308,26 +308,33 @@ static int ntfs_remount(struct super_block *sb, int *flags, char *opt)
 	ntfs_volume *vol = NTFS_SB(sb);
 
 	ntfs_debug("Entering with remount options string: %s", opt);
-
 #ifndef NTFS_RW
 	/* For read-only compiled driver, enforce all read-only flags. */
 	*flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME;
-#else
+#else /* ! NTFS_RW */
 	/*
 	 * For the read-write compiled driver, if we are remounting read-write,
-	 * make sure there aren't any volume errors.
+	 * make sure there aren't any volume errors and empty the lofgile.
 	 */
 	if ((sb->s_flags & MS_RDONLY) && !(*flags & MS_RDONLY)) {
+		static const char *es = ".  Cannot remount read-write.";
+
 		if (NVolErrors(vol)) {
-			ntfs_error(sb, "Volume has errors and is read-only. "
-					"Cannot remount read-write.");
+			ntfs_error(sb, "Volume has errors and is read-only%s",
+					es);
+			return -EROFS;
+		}
+		if (!ntfs_empty_logfile(vol->logfile_ino)) {
+			ntfs_error(sb, "Failed to empty journal $LogFile%s",
+					es);
+			NVolSetErrors(vol);
 			return -EROFS;
 		}
 	}
 	// TODO:  For now we enforce no atime and dir atime updates as they are
 	// not implemented.
 	*flags |= MS_NOATIME | MS_NODIRATIME;
-#endif
+#endif /* ! NTFS_RW */
 
 	// FIXME/TODO: If left like this we will have problems with rw->ro and
 	// ro->rw, as well as with sync->async and vice versa remounts.
@@ -345,7 +352,7 @@ static int ntfs_remount(struct super_block *sb, int *flags, char *opt)
 
 	if (!parse_options(vol, opt))
 		return -EINVAL;
-
+	ntfs_debug("Done.");
 	return 0;
 }
 
@@ -1156,10 +1163,25 @@ static BOOL load_system_files(ntfs_volume *vol)
 					!vol->logfile_ino ? es1 : es2, es3);
 		/* This will prevent a read-write remount. */
 		NVolSetErrors(vol);
+	/* If a read-write mount, empty the logfile. */
+	} else if (!(sb->s_flags & MS_RDONLY) &&
+			!ntfs_empty_logfile(vol->logfile_ino)) {
+		static const char *es1 = "Failed to empty $LogFile";
+		static const char *es2 = ".  Mount in Windows.";
+
+		/* Convert to a read-only mount. */
+		if (!(vol->on_errors & (ON_ERRORS_REMOUNT_RO |
+				ON_ERRORS_CONTINUE))) {
+			ntfs_error(sb, "%s and neither on_errors=continue nor "
+					"on_errors=remount-ro was specified%s",
+					es1, es2);
+			goto iput_logfile_err_out;
+		}
+		sb->s_flags |= MS_RDONLY | MS_NOATIME | MS_NODIRATIME;
+		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
+		/* This will prevent a read-write remount. */
+		NVolSetErrors(vol);
 	}
-	// FIXME: Empty the logfile, but only if not read-only.
-	// FIXME: What happens if someone remounts rw? We need to empty the file
-	// then. We need a flag to tell us whether we have done it already.
 #endif
 	/*
 	 * Get the inode for the attribute definitions file and parse the
@@ -2124,4 +2146,3 @@ MODULE_PARM_DESC(debug_msgs, "Enable debug messages.");
 
 module_init(init_ntfs_fs)
 module_exit(exit_ntfs_fs)
-