NTFS: Determine the mft mirror size as the number of mirrored mft records

      and store it in ntfs_volume->mftmirr_size (fs/ntfs/super.c).

fs/ntfs/ChangeLog

@@ -35,6 +35,8 @@ ToDo:
 	  fs/ntfs/inode.h and use it to declare NInoTest{Set,Clear}Dirty.
 	- Move typedefs for ntfs_attr and test_t from fs/ntfs/inode.c to
 	  fs/ntfs/inode.h so they can be used elsewhere.
+	- Determine the mft mirror size as the number of mirrored mft records
+	  and store it in ntfs_volume->mftmirr_size (fs/ntfs/super.c).
 
 2.1.7 - Enable NFS exporting of mounted NTFS volumes.
 

fs/ntfs/mft.h

@@ -45,7 +45,7 @@ static inline void unmap_extent_mft_record(ntfs_inode *ni)
 
 #ifdef NTFS_RW
 
-/*
+/**
  * flush_dcache_mft_record_page - flush_dcache_page() for mft records
  * @ni:		ntfs inode structure of mft record
  *

fs/ntfs/super.c

@@ -657,6 +657,20 @@ static BOOL parse_ntfs_boot_sector(ntfs_volume *vol, const NTFS_BOOT_SECTOR *b)
 	}
 	vol->mftmirr_lcn = ll;
 	ntfs_debug("vol->mftmirr_lcn = 0x%Lx", (long long)vol->mftmirr_lcn);
+	/*
+	 * Work out the size of the mft mirror in number of mft records. If the
+	 * cluster size is less than or equal to the size taken by four mft
+	 * records, the mft mirror stores the first four mft records. If the
+	 * cluster size is bigger than the size taken by four mft records, the
+	 * mft mirror contains as many mft records as will fit into one
+	 * cluster.
+	 */
+	if (vol->cluster_size <= (4 << vol->mft_record_size_bits))
+		vol->mftmirr_size = 4;
+	else
+		vol->mftmirr_size = vol->cluster_size >>
+				vol->mft_record_size_bits;
+	ntfs_debug("vol->mftmirr_size = %i", vol->mftmirr_size);
 	vol->serial_no = le64_to_cpu(b->volume_serial_number);
 	ntfs_debug("vol->serial_no = 0x%Lx",
 			(unsigned long long)vol->serial_no);

fs/ntfs/volume.h

@@ -2,7 +2,7 @@
  * volume.h - Defines for volume structures in NTFS Linux kernel driver. Part
  *	      of the Linux-NTFS project.
  *
- * Copyright (c) 2001,2002 Anton Altaparmakov.
+ * Copyright (c) 2001-2004 Anton Altaparmakov.
  * Copyright (c) 2002 Richard Russon.
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -25,6 +25,7 @@
 #define _LINUX_NTFS_VOLUME_H
 
 #include "types.h"
+#include "layout.h"
 
 /*
  * The NTFS in memory super block structure.
@@ -83,13 +84,17 @@ typedef struct {
 					   bits in mft bitmap. */
 
 	struct inode *mftmirr_ino;	/* The VFS inode of $MFTMirr. */
+	int mftmirr_size;		/* Size of mft mirror in mft records. */
+
 	struct inode *lcnbmp_ino;	/* The VFS inode of $Bitmap. */
 	struct rw_semaphore lcnbmp_lock; /* Lock for serializing accesses to the
 					    cluster bitmap ($Bitmap/$DATA). */
+
 	struct inode *vol_ino;		/* The VFS inode of $Volume. */
-	unsigned long vol_flags;	/* Volume flags (VOLUME_*). */
+	VOLUME_FLAGS vol_flags;		/* Volume flags (VOLUME_*). */
 	u8 major_ver;			/* Ntfs major version of volume. */
 	u8 minor_ver;			/* Ntfs minor version of volume. */
+
 	struct inode *root_ino;		/* The VFS inode of the root
 					   directory. */
 	struct inode *secure_ino;	/* The VFS inode of $Secure (NTFS3.0+
@@ -133,4 +138,3 @@ NVOL_FNS(ShowSystemFiles)
 NVOL_FNS(CaseSensitive)
 
 #endif /* _LINUX_NTFS_VOLUME_H */
-