NTFS: Remove vol->nr_mft_records as it was pretty meaningless and optimize

      the calculation of total/free inodes as used by statfs().
Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

fs/ntfs/ChangeLog

@@ -21,6 +21,11 @@ ToDo/Notes:
 	- Enable the code for setting the NT4 compatibility flag when we start
 	  making NTFS 1.2 specific modifications.
 
+2.1.18-WIP
+
+	- Remove vol->nr_mft_records as it was pretty meaningless and optimize
+	  the calculation of total/free inodes as used by statfs().
+
 2.1.17 - Fix bugs in mount time error code paths and other updates.
 
 	- Implement bitmap modification code (fs/ntfs/bitmap.[hc]).  This

fs/ntfs/Makefile

@@ -6,7 +6,7 @@ ntfs-objs := aops.o attrib.o collate.o compress.o debug.o dir.o file.o \
 	     index.o inode.o mft.o mst.o namei.o super.o sysctl.o unistr.o \
 	     upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.17\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.18-WIP\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG

fs/ntfs/inode.c

@@ -1900,8 +1900,6 @@ int ntfs_read_inode_mount(struct inode *vi)
 
 		/* Are we in the first extent? */
 		if (!next_vcn) {
-			u64 ll;
-
 			if (attr->data.non_resident.lowest_vcn) {
 				ntfs_error(sb, "First extent of $DATA "
 						"attribute has non zero "
@@ -1920,17 +1918,15 @@ int ntfs_read_inode_mount(struct inode *vi)
 					non_resident.initialized_size);
 			ni->allocated_size = sle64_to_cpu(
 					attr->data.non_resident.allocated_size);
-			/* Set the number of mft records. */
-			ll = vi->i_size >> vol->mft_record_size_bits;
 			/*
 			 * Verify the number of mft records does not exceed
 			 * 2^32 - 1.
 			 */
-			if (ll >= (1ULL << 32)) {
+			if ((vi->i_size >> vol->mft_record_size_bits) >=
+					(1ULL << 32)) {
 				ntfs_error(sb, "$MFT is too big! Aborting.");
 				goto put_err_out;
 			}
-			vol->nr_mft_records = ll;
 			/*
 			 * We have got the first extent of the runlist for
 			 * $MFT which means it is now relatively safe to call

fs/ntfs/super.c

@@ -2012,7 +2012,7 @@ static s64 get_nr_free_clusters(ntfs_volume *vol)
  */
 static unsigned long __get_nr_free_mft_records(ntfs_volume *vol)
 {
-	s64 nr_free = vol->nr_mft_records;
+	s64 nr_free;
 	u32 *kaddr;
 	struct address_space *mapping = vol->mftbmp_ino->i_mapping;
 	filler_t *readpage = (filler_t*)mapping->a_ops->readpage;
@@ -2021,13 +2021,16 @@ static unsigned long __get_nr_free_mft_records(ntfs_volume *vol)
 	unsigned int max_size;
 
 	ntfs_debug("Entering.");
+	/* Number of mft records in file system (at this point in time). */
+	nr_free = vol->mft_ino->i_size >> vol->mft_record_size_bits;
 	/*
-	 * Convert the number of bits into bytes rounded up, then convert into
-	 * multiples of PAGE_CACHE_SIZE, rounding up so that if we have one
-	 * full and one partial page max_index = 2.
+	 * Convert the maximum number of set bits into bytes rounded up, then
+	 * convert into multiples of PAGE_CACHE_SIZE, rounding up so that if we
+	 * have one full and one partial page max_index = 2.
 	 */
-	max_index = (((vol->nr_mft_records + 7) >> 3) + PAGE_CACHE_SIZE - 1) >>
-			PAGE_CACHE_SHIFT;
+	max_index = ((((NTFS_I(vol->mft_ino)->initialized_size >>
+			vol->mft_record_size_bits) + 7) >> 3) +
+			PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
 	/* Use multiples of 4 bytes. */
 	max_size = PAGE_CACHE_SIZE >> 2;
 	ntfs_debug("Reading $MFT/$BITMAP, max_index = 0x%lx, max_size = "
@@ -2122,9 +2125,9 @@ static int ntfs_statfs(struct super_block *sb, struct kstatfs *sfs)
 	sfs->f_bavail = sfs->f_bfree = size;
 	/* Serialize accesses to the inode bitmap. */
 	down_read(&vol->mftbmp_lock);
-	/* Total file nodes in file system (at this moment in time). */
+	/* Number of inodes in file system (at this point in time). */
 	sfs->f_files = vol->mft_ino->i_size >> vol->mft_record_size_bits;
-	/* Free file nodes in fs (based on current total count). */
+	/* Free inodes in fs (based on current total count). */
 	sfs->f_ffree = __get_nr_free_mft_records(vol);
 	up_read(&vol->mftbmp_lock);
 	/*

fs/ntfs/volume.h

@@ -95,9 +95,6 @@ typedef struct {
 	struct inode *mftbmp_ino;	/* Attribute inode for $MFT/$BITMAP. */
 	struct rw_semaphore mftbmp_lock; /* Lock for serializing accesses to the
 					    mft record bitmap ($MFT/$BITMAP). */
-	unsigned long nr_mft_records;	/* Number of mft records == number of
-					   bits in mft bitmap. */
-
 #ifdef NTFS_RW
 	struct inode *mftmirr_ino;	/* The VFS inode of $MFTMirr. */
 	int mftmirr_size;		/* Size of mft mirror in mft records. */