// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * super.c - NTFS kernel super block handling. Part of the Linux-NTFS project.
   *

   * Copyright (c) 2001-2012 Anton Altaparmakov and Tuxera Inc.

   * Copyright (c) 2001,2002 Richard Russon

   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  
  #include <linux/stddef.h>
  #include <linux/init.h>

  #include <linux/slab.h>

  #include <linux/string.h>
  #include <linux/spinlock.h>

  #include <linux/blkdev.h>	/* For bdev_logical_block_size(). */

  #include <linux/backing-dev.h>
  #include <linux/buffer_head.h>
  #include <linux/vfs.h>
  #include <linux/moduleparam.h>

  #include <linux/bitmap.h>

  
  #include "sysctl.h"
  #include "logfile.h"
  #include "quota.h"

  #include "usnjrnl.h"

  #include "dir.h"
  #include "debug.h"
  #include "index.h"

  #include "inode.h"

  #include "aops.h"

  #include "layout.h"

  #include "malloc.h"
  #include "ntfs.h"

  /* Number of mounted filesystems which have compression enabled. */

  static unsigned long ntfs_nr_compression_users;
  
  /* A global default upcase table and a corresponding reference count. */

  static ntfschar *default_upcase;
  static unsigned long ntfs_nr_upcase_users;

  
  /* Error constants/strings used in inode.c::ntfs_show_options(). */
  typedef enum {
  	/* One of these must be present, default is ON_ERRORS_CONTINUE. */
  	ON_ERRORS_PANIC			= 0x01,
  	ON_ERRORS_REMOUNT_RO		= 0x02,
  	ON_ERRORS_CONTINUE		= 0x04,
  	/* Optional, can be combined with any of the above. */
  	ON_ERRORS_RECOVER		= 0x10,
  } ON_ERRORS_ACTIONS;
  
  const option_t on_errors_arr[] = {
  	{ ON_ERRORS_PANIC,	"panic" },
  	{ ON_ERRORS_REMOUNT_RO,	"remount-ro", },
  	{ ON_ERRORS_CONTINUE,	"continue", },
  	{ ON_ERRORS_RECOVER,	"recover" },
  	{ 0,			NULL }
  };
  
  /**
   * simple_getbool -
   *
   * Copied from old ntfs driver (which copied from vfat driver).
   */

  static int simple_getbool(char *s, bool *setval)

  {
  	if (s) {
  		if (!strcmp(s, "1") || !strcmp(s, "yes") || !strcmp(s, "true"))

  			*setval = true;

  		else if (!strcmp(s, "0") || !strcmp(s, "no") ||
  							!strcmp(s, "false"))

  			*setval = false;

  		else
  			return 0;
  	} else

  		*setval = true;

  	return 1;
  }
  
  /**
   * parse_options - parse the (re)mount options
   * @vol:	ntfs volume
   * @opt:	string containing the (re)mount options
   *
   * Parse the recognized options in @opt for the ntfs volume described by @vol.
   */

  static bool parse_options(ntfs_volume *vol, char *opt)

  {
  	char *p, *v, *ov;
  	static char *utf8 = "utf8";
  	int errors = 0, sloppy = 0;

  	kuid_t uid = INVALID_UID;
  	kgid_t gid = INVALID_GID;

  	umode_t fmask = (umode_t)-1, dmask = (umode_t)-1;

  	int mft_zone_multiplier = -1, on_errors = -1;

  	int show_sys_files = -1, case_sensitive = -1, disable_sparse = -1;

  	struct nls_table *nls_map = NULL, *old_nls;
  
  	/* I am lazy... (-8 */
  #define NTFS_GETOPT_WITH_DEFAULT(option, variable, default_value)	\
  	if (!strcmp(p, option)) {					\
  		if (!v || !*v)						\
  			variable = default_value;			\
  		else {							\
  			variable = simple_strtoul(ov = v, &v, 0);	\
  			if (*v)						\
  				goto needs_val;				\
  		}							\
  	}
  #define NTFS_GETOPT(option, variable)					\
  	if (!strcmp(p, option)) {					\
  		if (!v || !*v)						\
  			goto needs_arg;					\
  		variable = simple_strtoul(ov = v, &v, 0);		\
  		if (*v)							\
  			goto needs_val;					\
  	}

  #define NTFS_GETOPT_UID(option, variable)				\
  	if (!strcmp(p, option)) {					\
  		uid_t uid_value;					\
  		if (!v || !*v)						\
  			goto needs_arg;					\
  		uid_value = simple_strtoul(ov = v, &v, 0);		\
  		if (*v)							\
  			goto needs_val;					\
  		variable = make_kuid(current_user_ns(), uid_value);	\
  		if (!uid_valid(variable))				\
  			goto needs_val;					\
  	}
  #define NTFS_GETOPT_GID(option, variable)				\
  	if (!strcmp(p, option)) {					\
  		gid_t gid_value;					\
  		if (!v || !*v)						\
  			goto needs_arg;					\
  		gid_value = simple_strtoul(ov = v, &v, 0);		\
  		if (*v)							\
  			goto needs_val;					\
  		variable = make_kgid(current_user_ns(), gid_value);	\
  		if (!gid_valid(variable))				\
  			goto needs_val;					\
  	}

  #define NTFS_GETOPT_OCTAL(option, variable)				\
  	if (!strcmp(p, option)) {					\
  		if (!v || !*v)						\
  			goto needs_arg;					\
  		variable = simple_strtoul(ov = v, &v, 8);		\
  		if (*v)							\
  			goto needs_val;					\
  	}

  #define NTFS_GETOPT_BOOL(option, variable)				\
  	if (!strcmp(p, option)) {					\

  		bool val;						\

  		if (!simple_getbool(v, &val))				\
  			goto needs_bool;				\
  		variable = val;						\
  	}
  #define NTFS_GETOPT_OPTIONS_ARRAY(option, variable, opt_array)		\
  	if (!strcmp(p, option)) {					\
  		int _i;							\
  		if (!v || !*v)						\
  			goto needs_arg;					\
  		ov = v;							\
  		if (variable == -1)					\
  			variable = 0;					\
  		for (_i = 0; opt_array[_i].str && *opt_array[_i].str; _i++) \
  			if (!strcmp(opt_array[_i].str, v)) {		\
  				variable |= opt_array[_i].val;		\
  				break;					\
  			}						\
  		if (!opt_array[_i].str || !*opt_array[_i].str)		\
  			goto needs_val;					\
  	}
  	if (!opt || !*opt)
  		goto no_mount_options;
  	ntfs_debug("Entering with mount options string: %s", opt);
  	while ((p = strsep(&opt, ","))) {
  		if ((v = strchr(p, '=')))
  			*v++ = 0;

  		NTFS_GETOPT_UID("uid", uid)
  		else NTFS_GETOPT_GID("gid", gid)

  		else NTFS_GETOPT_OCTAL("umask", fmask = dmask)
  		else NTFS_GETOPT_OCTAL("fmask", fmask)
  		else NTFS_GETOPT_OCTAL("dmask", dmask)

  		else NTFS_GETOPT("mft_zone_multiplier", mft_zone_multiplier)

  		else NTFS_GETOPT_WITH_DEFAULT("sloppy", sloppy, true)

  		else NTFS_GETOPT_BOOL("show_sys_files", show_sys_files)
  		else NTFS_GETOPT_BOOL("case_sensitive", case_sensitive)

  		else NTFS_GETOPT_BOOL("disable_sparse", disable_sparse)

  		else NTFS_GETOPT_OPTIONS_ARRAY("errors", on_errors,
  				on_errors_arr)
  		else if (!strcmp(p, "posix") || !strcmp(p, "show_inodes"))
  			ntfs_warning(vol->sb, "Ignoring obsolete option %s.",
  					p);
  		else if (!strcmp(p, "nls") || !strcmp(p, "iocharset")) {
  			if (!strcmp(p, "iocharset"))
  				ntfs_warning(vol->sb, "Option iocharset is "
  						"deprecated. Please use "
  						"option nls=<charsetname> in "
  						"the future.");
  			if (!v || !*v)
  				goto needs_arg;
  use_utf8:
  			old_nls = nls_map;
  			nls_map = load_nls(v);
  			if (!nls_map) {
  				if (!old_nls) {
  					ntfs_error(vol->sb, "NLS character set "
  							"%s not found.", v);

  					return false;

  				}
  				ntfs_error(vol->sb, "NLS character set %s not "
  						"found. Using previous one %s.",
  						v, old_nls->charset);
  				nls_map = old_nls;
  			} else /* nls_map */ {

  				unload_nls(old_nls);

  			}
  		} else if (!strcmp(p, "utf8")) {

  			bool val = false;

  			ntfs_warning(vol->sb, "Option utf8 is no longer "
  				   "supported, using option nls=utf8. Please "
  				   "use option nls=utf8 in the future and "
  				   "make sure utf8 is compiled either as a "
  				   "module or into the kernel.");
  			if (!v || !*v)

  				val = true;

  			else if (!simple_getbool(v, &val))
  				goto needs_bool;
  			if (val) {
  				v = utf8;
  				goto use_utf8;
  			}
  		} else {
  			ntfs_error(vol->sb, "Unrecognized mount option %s.", p);
  			if (errors < INT_MAX)
  				errors++;
  		}
  #undef NTFS_GETOPT_OPTIONS_ARRAY
  #undef NTFS_GETOPT_BOOL
  #undef NTFS_GETOPT
  #undef NTFS_GETOPT_WITH_DEFAULT
  	}
  no_mount_options:
  	if (errors && !sloppy)

  		return false;

  	if (sloppy)
  		ntfs_warning(vol->sb, "Sloppy option given. Ignoring "
  				"unrecognized mount option(s) and continuing.");
  	/* Keep this first! */
  	if (on_errors != -1) {
  		if (!on_errors) {
  			ntfs_error(vol->sb, "Invalid errors option argument "
  					"or bug in options parser.");

  			return false;

  		}
  	}
  	if (nls_map) {
  		if (vol->nls_map && vol->nls_map != nls_map) {
  			ntfs_error(vol->sb, "Cannot change NLS character set "
  					"on remount.");

  			return false;

  		} /* else (!vol->nls_map) */
  		ntfs_debug("Using NLS character set %s.", nls_map->charset);
  		vol->nls_map = nls_map;
  	} else /* (!nls_map) */ {
  		if (!vol->nls_map) {
  			vol->nls_map = load_nls_default();
  			if (!vol->nls_map) {
  				ntfs_error(vol->sb, "Failed to load default "
  						"NLS character set.");

  				return false;

  			}
  			ntfs_debug("Using default NLS character set (%s).",
  					vol->nls_map->charset);
  		}
  	}
  	if (mft_zone_multiplier != -1) {
  		if (vol->mft_zone_multiplier && vol->mft_zone_multiplier !=
  				mft_zone_multiplier) {
  			ntfs_error(vol->sb, "Cannot change mft_zone_multiplier "
  					"on remount.");

  			return false;

  		}
  		if (mft_zone_multiplier < 1 || mft_zone_multiplier > 4) {
  			ntfs_error(vol->sb, "Invalid mft_zone_multiplier. "
  					"Using default value, i.e. 1.");
  			mft_zone_multiplier = 1;
  		}
  		vol->mft_zone_multiplier = mft_zone_multiplier;
  	}
  	if (!vol->mft_zone_multiplier)
  		vol->mft_zone_multiplier = 1;
  	if (on_errors != -1)
  		vol->on_errors = on_errors;
  	if (!vol->on_errors || vol->on_errors == ON_ERRORS_RECOVER)
  		vol->on_errors |= ON_ERRORS_CONTINUE;

  	if (uid_valid(uid))

  		vol->uid = uid;

  	if (gid_valid(gid))

  		vol->gid = gid;

  	if (fmask != (umode_t)-1)

  		vol->fmask = fmask;

  	if (dmask != (umode_t)-1)

  		vol->dmask = dmask;
  	if (show_sys_files != -1) {
  		if (show_sys_files)
  			NVolSetShowSystemFiles(vol);
  		else
  			NVolClearShowSystemFiles(vol);
  	}
  	if (case_sensitive != -1) {
  		if (case_sensitive)
  			NVolSetCaseSensitive(vol);
  		else
  			NVolClearCaseSensitive(vol);
  	}

  	if (disable_sparse != -1) {
  		if (disable_sparse)
  			NVolClearSparseEnabled(vol);
  		else {
  			if (!NVolSparseEnabled(vol) &&
  					vol->major_ver && vol->major_ver < 3)
  				ntfs_warning(vol->sb, "Not enabling sparse "
  						"support due to NTFS volume "
  						"version %i.%i (need at least "
  						"version 3.0).", vol->major_ver,
  						vol->minor_ver);
  			else
  				NVolSetSparseEnabled(vol);
  		}
  	}

  	return true;

  needs_arg:
  	ntfs_error(vol->sb, "The %s option requires an argument.", p);

  	return false;

  needs_bool:
  	ntfs_error(vol->sb, "The %s option requires a boolean argument.", p);

  	return false;

  needs_val:
  	ntfs_error(vol->sb, "Invalid %s option argument: %s", p, ov);

  	return false;

  }
  
  #ifdef NTFS_RW
  
  /**
   * ntfs_write_volume_flags - write new flags to the volume information flags
   * @vol:	ntfs volume on which to modify the flags
   * @flags:	new flags value for the volume information flags
   *
   * Internal function.  You probably want to use ntfs_{set,clear}_volume_flags()
   * instead (see below).
   *
   * Replace the volume information flags on the volume @vol with the value
   * supplied in @flags.  Note, this overwrites the volume information flags, so
   * make sure to combine the flags you want to modify with the old flags and use
   * the result when calling ntfs_write_volume_flags().
   *
   * Return 0 on success and -errno on error.
   */
  static int ntfs_write_volume_flags(ntfs_volume *vol, const VOLUME_FLAGS flags)
  {
  	ntfs_inode *ni = NTFS_I(vol->vol_ino);
  	MFT_RECORD *m;
  	VOLUME_INFORMATION *vi;
  	ntfs_attr_search_ctx *ctx;
  	int err;
  
  	ntfs_debug("Entering, old flags = 0x%x, new flags = 0x%x.",
  			le16_to_cpu(vol->vol_flags), le16_to_cpu(flags));
  	if (vol->vol_flags == flags)
  		goto done;
  	BUG_ON(!ni);
  	m = map_mft_record(ni);
  	if (IS_ERR(m)) {
  		err = PTR_ERR(m);
  		goto err_out;
  	}
  	ctx = ntfs_attr_get_search_ctx(ni, m);
  	if (!ctx) {
  		err = -ENOMEM;
  		goto put_unm_err_out;
  	}
  	err = ntfs_attr_lookup(AT_VOLUME_INFORMATION, NULL, 0, 0, 0, NULL, 0,
  			ctx);
  	if (err)
  		goto put_unm_err_out;
  	vi = (VOLUME_INFORMATION*)((u8*)ctx->attr +
  			le16_to_cpu(ctx->attr->data.resident.value_offset));
  	vol->vol_flags = vi->flags = flags;
  	flush_dcache_mft_record_page(ctx->ntfs_ino);
  	mark_mft_record_dirty(ctx->ntfs_ino);
  	ntfs_attr_put_search_ctx(ctx);
  	unmap_mft_record(ni);
  done:
  	ntfs_debug("Done.");
  	return 0;
  put_unm_err_out:
  	if (ctx)
  		ntfs_attr_put_search_ctx(ctx);
  	unmap_mft_record(ni);
  err_out:
  	ntfs_error(vol->sb, "Failed with error code %i.", -err);
  	return err;
  }
  
  /**
   * ntfs_set_volume_flags - set bits in the volume information flags
   * @vol:	ntfs volume on which to modify the flags
   * @flags:	flags to set on the volume
   *
   * Set the bits in @flags in the volume information flags on the volume @vol.
   *
   * Return 0 on success and -errno on error.
   */
  static inline int ntfs_set_volume_flags(ntfs_volume *vol, VOLUME_FLAGS flags)
  {
  	flags &= VOLUME_FLAGS_MASK;
  	return ntfs_write_volume_flags(vol, vol->vol_flags | flags);
  }
  
  /**
   * ntfs_clear_volume_flags - clear bits in the volume information flags
   * @vol:	ntfs volume on which to modify the flags
   * @flags:	flags to clear on the volume
   *
   * Clear the bits in @flags in the volume information flags on the volume @vol.
   *
   * Return 0 on success and -errno on error.
   */
  static inline int ntfs_clear_volume_flags(ntfs_volume *vol, VOLUME_FLAGS flags)
  {
  	flags &= VOLUME_FLAGS_MASK;
  	flags = vol->vol_flags & cpu_to_le16(~le16_to_cpu(flags));
  	return ntfs_write_volume_flags(vol, flags);
  }
  
  #endif /* NTFS_RW */
  
  /**
   * ntfs_remount - change the mount options of a mounted ntfs filesystem
   * @sb:		superblock of mounted ntfs filesystem
   * @flags:	remount flags
   * @opt:	remount options string
   *
   * Change the mount options of an already mounted ntfs filesystem.
   *
   * 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.
   */
  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);

  	sync_filesystem(sb);

  #ifndef NTFS_RW

  	/* For read-only compiled driver, enforce read-only flag. */

  	*flags |= SB_RDONLY;

  #else /* NTFS_RW */
  	/*
  	 * For the read-write compiled driver, if we are remounting read-write,
  	 * make sure there are no volume errors and that no unsupported volume
  	 * flags are set.  Also, empty the logfile journal as it would become
  	 * stale as soon as something is written to the volume and mark the
  	 * volume dirty so that chkdsk is run if the volume is not umounted
  	 * cleanly.  Finally, mark the quotas out of date so Windows rescans
  	 * the volume on boot and updates them.
  	 *
  	 * When remounting read-only, mark the volume clean if no volume errors

  	 * have occurred.

  	 */

  	if (sb_rdonly(sb) && !(*flags & SB_RDONLY)) {

  		static const char *es = ".  Cannot remount read-write.";
  
  		/* Remounting read-write. */
  		if (NVolErrors(vol)) {
  			ntfs_error(sb, "Volume has errors and is read-only%s",
  					es);
  			return -EROFS;
  		}
  		if (vol->vol_flags & VOLUME_IS_DIRTY) {
  			ntfs_error(sb, "Volume is dirty and read-only%s", es);
  			return -EROFS;
  		}

  		if (vol->vol_flags & VOLUME_MODIFIED_BY_CHKDSK) {
  			ntfs_error(sb, "Volume has been modified by chkdsk "
  					"and is read-only%s", es);
  			return -EROFS;
  		}

  		if (vol->vol_flags & VOLUME_MUST_MOUNT_RO_MASK) {

  			ntfs_error(sb, "Volume has unsupported flags set "
  					"(0x%x) and is read-only%s",
  					(unsigned)le16_to_cpu(vol->vol_flags),
  					es);

  			return -EROFS;
  		}
  		if (ntfs_set_volume_flags(vol, VOLUME_IS_DIRTY)) {
  			ntfs_error(sb, "Failed to set dirty bit in volume "
  					"information flags%s", es);
  			return -EROFS;
  		}
  #if 0
  		// TODO: Enable this code once we start modifying anything that
  		//	 is different between NTFS 1.2 and 3.x...
  		/* Set NT4 compatibility flag on newer NTFS version volumes. */
  		if ((vol->major_ver > 1)) {
  			if (ntfs_set_volume_flags(vol, VOLUME_MOUNTED_ON_NT4)) {
  				ntfs_error(sb, "Failed to set NT4 "
  						"compatibility flag%s", es);
  				NVolSetErrors(vol);
  				return -EROFS;
  			}
  		}
  #endif
  		if (!ntfs_empty_logfile(vol->logfile_ino)) {
  			ntfs_error(sb, "Failed to empty journal $LogFile%s",
  					es);
  			NVolSetErrors(vol);
  			return -EROFS;
  		}
  		if (!ntfs_mark_quotas_out_of_date(vol)) {
  			ntfs_error(sb, "Failed to mark quotas out of date%s",
  					es);
  			NVolSetErrors(vol);
  			return -EROFS;
  		}

  		if (!ntfs_stamp_usnjrnl(vol)) {

  			ntfs_error(sb, "Failed to stamp transaction log "

  					"($UsnJrnl)%s", es);
  			NVolSetErrors(vol);
  			return -EROFS;
  		}

  	} else if (!sb_rdonly(sb) && (*flags & SB_RDONLY)) {

  		/* Remounting read-only. */
  		if (!NVolErrors(vol)) {
  			if (ntfs_clear_volume_flags(vol, VOLUME_IS_DIRTY))
  				ntfs_warning(sb, "Failed to clear dirty bit "
  						"in volume information "
  						"flags.  Run chkdsk.");
  		}
  	}
  #endif /* NTFS_RW */
  
  	// TODO: Deal with *flags.

  	if (!parse_options(vol, opt))

  		return -EINVAL;

  	ntfs_debug("Done.");
  	return 0;
  }
  
  /**
   * is_boot_sector_ntfs - check whether a boot sector is a valid NTFS boot sector
   * @sb:		Super block of the device to which @b belongs.
   * @b:		Boot sector of device @sb to check.

   * @silent:	If 'true', all output will be silenced.

   *
   * is_boot_sector_ntfs() checks whether the boot sector @b is a valid NTFS boot

   * sector. Returns 'true' if it is valid and 'false' if not.

   *
   * @sb is only needed for warning/error output, i.e. it can be NULL when silent

   * is 'true'.

   */

  static bool is_boot_sector_ntfs(const struct super_block *sb,
  		const NTFS_BOOT_SECTOR *b, const bool silent)

  {
  	/*
  	 * Check that checksum == sum of u32 values from b to the checksum

  	 * 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 && !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)

  			ntfs_warning(sb, "Invalid boot sector checksum.");

  	}
  	/* Check OEMidentifier is "NTFS    " */
  	if (b->oem_id != magicNTFS)
  		goto not_ntfs;
  	/* Check bytes per sector value is between 256 and 4096. */
  	if (le16_to_cpu(b->bpb.bytes_per_sector) < 0x100 ||
  			le16_to_cpu(b->bpb.bytes_per_sector) > 0x1000)
  		goto not_ntfs;
  	/* Check sectors per cluster value is valid. */
  	switch (b->bpb.sectors_per_cluster) {
  	case 1: case 2: case 4: case 8: case 16: case 32: case 64: case 128:
  		break;
  	default:
  		goto not_ntfs;
  	}

  	/* Check the cluster size is not above the maximum (64kiB). */

  	if ((u32)le16_to_cpu(b->bpb.bytes_per_sector) *

  			b->bpb.sectors_per_cluster > NTFS_MAX_CLUSTER_SIZE)

  		goto not_ntfs;
  	/* Check reserved/unused fields are really zero. */
  	if (le16_to_cpu(b->bpb.reserved_sectors) ||
  			le16_to_cpu(b->bpb.root_entries) ||
  			le16_to_cpu(b->bpb.sectors) ||
  			le16_to_cpu(b->bpb.sectors_per_fat) ||
  			le32_to_cpu(b->bpb.large_sectors) || b->bpb.fats)
  		goto not_ntfs;
  	/* Check clusters per file mft record value is valid. */
  	if ((u8)b->clusters_per_mft_record < 0xe1 ||
  			(u8)b->clusters_per_mft_record > 0xf7)
  		switch (b->clusters_per_mft_record) {
  		case 1: case 2: case 4: case 8: case 16: case 32: case 64:
  			break;
  		default:
  			goto not_ntfs;
  		}
  	/* Check clusters per index block value is valid. */
  	if ((u8)b->clusters_per_index_record < 0xe1 ||
  			(u8)b->clusters_per_index_record > 0xf7)
  		switch (b->clusters_per_index_record) {
  		case 1: case 2: case 4: case 8: case 16: case 32: case 64:
  			break;
  		default:
  			goto not_ntfs;
  		}
  	/*
  	 * Check for valid end of sector marker. We will work without it, but
  	 * 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))

  		ntfs_warning(sb, "Invalid end of sector marker.");

  	return true;

  not_ntfs:

  	return false;

  }
  
  /**
   * read_ntfs_boot_sector - read the NTFS boot sector of a device
   * @sb:		super block of device to read the boot sector from
   * @silent:	if true, suppress all output
   *
   * Reads the boot sector from the device and validates it. If that fails, tries
   * to read the backup boot sector, first from the end of the device a-la NT4 and
   * later and then from the middle of the device a-la NT3.51 and before.
   *
   * If a valid boot sector is found but it is not the primary boot sector, we
   * repair the primary boot sector silently (unless the device is read-only or
   * the primary boot sector is not accessible).
   *
   * NOTE: To call this function, @sb must have the fields s_dev, the ntfs super
   * block (u.ntfs_sb), nr_blocks and the device flags (s_flags) initialized
   * to their respective values.
   *
   * Return the unlocked buffer head containing the boot sector or NULL on error.
   */
  static struct buffer_head *read_ntfs_boot_sector(struct super_block *sb,
  		const int silent)
  {
  	const char *read_err_str = "Unable to read %s boot sector.";
  	struct buffer_head *bh_primary, *bh_backup;

  	sector_t nr_blocks = NTFS_SB(sb)->nr_blocks;

  
  	/* Try to read primary boot sector. */
  	if ((bh_primary = sb_bread(sb, 0))) {
  		if (is_boot_sector_ntfs(sb, (NTFS_BOOT_SECTOR*)
  				bh_primary->b_data, silent))
  			return bh_primary;
  		if (!silent)
  			ntfs_error(sb, "Primary boot sector is invalid.");
  	} else if (!silent)
  		ntfs_error(sb, read_err_str, "primary");
  	if (!(NTFS_SB(sb)->on_errors & ON_ERRORS_RECOVER)) {
  		if (bh_primary)
  			brelse(bh_primary);
  		if (!silent)
  			ntfs_error(sb, "Mount option errors=recover not used. "
  					"Aborting without trying to recover.");
  		return NULL;
  	}
  	/* Try to read NT4+ backup boot sector. */
  	if ((bh_backup = sb_bread(sb, nr_blocks - 1))) {
  		if (is_boot_sector_ntfs(sb, (NTFS_BOOT_SECTOR*)
  				bh_backup->b_data, silent))
  			goto hotfix_primary_boot_sector;
  		brelse(bh_backup);
  	} else if (!silent)
  		ntfs_error(sb, read_err_str, "backup");
  	/* Try to read NT3.51- backup boot sector. */
  	if ((bh_backup = sb_bread(sb, nr_blocks >> 1))) {
  		if (is_boot_sector_ntfs(sb, (NTFS_BOOT_SECTOR*)
  				bh_backup->b_data, silent))
  			goto hotfix_primary_boot_sector;
  		if (!silent)
  			ntfs_error(sb, "Could not find a valid backup boot "
  					"sector.");
  		brelse(bh_backup);
  	} else if (!silent)
  		ntfs_error(sb, read_err_str, "backup");
  	/* We failed. Cleanup and return. */
  	if (bh_primary)
  		brelse(bh_primary);
  	return NULL;
  hotfix_primary_boot_sector:
  	if (bh_primary) {
  		/*
  		 * If we managed to read sector zero and the volume is not
  		 * read-only, copy the found, valid backup boot sector to the

  		 * primary boot sector.  Note we only copy the actual boot
  		 * sector structure, not the actual whole device sector as that
  		 * may be bigger and would potentially damage the $Boot system
  		 * file (FIXME: Would be nice to know if the backup boot sector
  		 * on a large sector device contains the whole boot loader or
  		 * just the first 512 bytes).

  		 */

  		if (!sb_rdonly(sb)) {

  			ntfs_warning(sb, "Hot-fix: Recovering invalid primary "
  					"boot sector from backup copy.");
  			memcpy(bh_primary->b_data, bh_backup->b_data,

  					NTFS_BLOCK_SIZE);

  			mark_buffer_dirty(bh_primary);
  			sync_dirty_buffer(bh_primary);
  			if (buffer_uptodate(bh_primary)) {
  				brelse(bh_backup);
  				return bh_primary;
  			}
  			ntfs_error(sb, "Hot-fix: Device write error while "
  					"recovering primary boot sector.");
  		} else {
  			ntfs_warning(sb, "Hot-fix: Recovery of primary boot "
  					"sector failed: Read-only mount.");
  		}
  		brelse(bh_primary);
  	}
  	ntfs_warning(sb, "Using backup boot sector.");
  	return bh_backup;
  }
  
  /**
   * parse_ntfs_boot_sector - parse the boot sector and store the data in @vol
   * @vol:	volume structure to initialise with data from boot sector
   * @b:		boot sector to parse
   *
   * Parse the ntfs boot sector @b and store all imporant information therein in

   * the ntfs super block @vol.  Return 'true' on success and 'false' on error.

   */

  static bool parse_ntfs_boot_sector(ntfs_volume *vol, const NTFS_BOOT_SECTOR *b)

  {
  	unsigned int sectors_per_cluster_bits, nr_hidden_sects;
  	int clusters_per_mft_record, clusters_per_index_record;
  	s64 ll;
  
  	vol->sector_size = le16_to_cpu(b->bpb.bytes_per_sector);
  	vol->sector_size_bits = ffs(vol->sector_size) - 1;
  	ntfs_debug("vol->sector_size = %i (0x%x)", vol->sector_size,
  			vol->sector_size);
  	ntfs_debug("vol->sector_size_bits = %i (0x%x)", vol->sector_size_bits,
  			vol->sector_size_bits);

  	if (vol->sector_size < vol->sb->s_blocksize) {
  		ntfs_error(vol->sb, "Sector size (%i) is smaller than the "
  				"device block size (%lu).  This is not "
  				"supported.  Sorry.", vol->sector_size,
  				vol->sb->s_blocksize);

  		return false;

  	}

  	ntfs_debug("sectors_per_cluster = 0x%x", b->bpb.sectors_per_cluster);
  	sectors_per_cluster_bits = ffs(b->bpb.sectors_per_cluster) - 1;
  	ntfs_debug("sectors_per_cluster_bits = 0x%x",
  			sectors_per_cluster_bits);
  	nr_hidden_sects = le32_to_cpu(b->bpb.hidden_sectors);
  	ntfs_debug("number of hidden sectors = 0x%x", nr_hidden_sects);
  	vol->cluster_size = vol->sector_size << sectors_per_cluster_bits;
  	vol->cluster_size_mask = vol->cluster_size - 1;
  	vol->cluster_size_bits = ffs(vol->cluster_size) - 1;
  	ntfs_debug("vol->cluster_size = %i (0x%x)", vol->cluster_size,
  			vol->cluster_size);
  	ntfs_debug("vol->cluster_size_mask = 0x%x", vol->cluster_size_mask);

  	ntfs_debug("vol->cluster_size_bits = %i", vol->cluster_size_bits);
  	if (vol->cluster_size < vol->sector_size) {
  		ntfs_error(vol->sb, "Cluster size (%i) is smaller than the "
  				"sector size (%i).  This is not supported.  "
  				"Sorry.", vol->cluster_size, vol->sector_size);

  		return false;

  	}
  	clusters_per_mft_record = b->clusters_per_mft_record;
  	ntfs_debug("clusters_per_mft_record = %i (0x%x)",
  			clusters_per_mft_record, clusters_per_mft_record);
  	if (clusters_per_mft_record > 0)
  		vol->mft_record_size = vol->cluster_size <<
  				(ffs(clusters_per_mft_record) - 1);
  	else
  		/*
  		 * When mft_record_size < cluster_size, clusters_per_mft_record
  		 * = -log2(mft_record_size) bytes. mft_record_size normaly is
  		 * 1024 bytes, which is encoded as 0xF6 (-10 in decimal).
  		 */
  		vol->mft_record_size = 1 << -clusters_per_mft_record;
  	vol->mft_record_size_mask = vol->mft_record_size - 1;
  	vol->mft_record_size_bits = ffs(vol->mft_record_size) - 1;
  	ntfs_debug("vol->mft_record_size = %i (0x%x)", vol->mft_record_size,
  			vol->mft_record_size);
  	ntfs_debug("vol->mft_record_size_mask = 0x%x",
  			vol->mft_record_size_mask);
  	ntfs_debug("vol->mft_record_size_bits = %i (0x%x)",
  			vol->mft_record_size_bits, vol->mft_record_size_bits);
  	/*

  	 * We cannot support mft record sizes above the PAGE_SIZE since

  	 * we store $MFT/$DATA, the table of mft records in the page cache.
  	 */

  	if (vol->mft_record_size > PAGE_SIZE) {

  		ntfs_error(vol->sb, "Mft record size (%i) exceeds the "

  				"PAGE_SIZE on your system (%lu).  "

  				"This is not supported.  Sorry.",

  				vol->mft_record_size, PAGE_SIZE);

  		return false;

  	}
  	/* We cannot support mft record sizes below the sector size. */
  	if (vol->mft_record_size < vol->sector_size) {
  		ntfs_error(vol->sb, "Mft record size (%i) is smaller than the "
  				"sector size (%i).  This is not supported.  "
  				"Sorry.", vol->mft_record_size,
  				vol->sector_size);

  		return false;

  	}
  	clusters_per_index_record = b->clusters_per_index_record;
  	ntfs_debug("clusters_per_index_record = %i (0x%x)",
  			clusters_per_index_record, clusters_per_index_record);
  	if (clusters_per_index_record > 0)
  		vol->index_record_size = vol->cluster_size <<
  				(ffs(clusters_per_index_record) - 1);
  	else
  		/*
  		 * When index_record_size < cluster_size,
  		 * clusters_per_index_record = -log2(index_record_size) bytes.
  		 * index_record_size normaly equals 4096 bytes, which is
  		 * encoded as 0xF4 (-12 in decimal).
  		 */
  		vol->index_record_size = 1 << -clusters_per_index_record;
  	vol->index_record_size_mask = vol->index_record_size - 1;
  	vol->index_record_size_bits = ffs(vol->index_record_size) - 1;
  	ntfs_debug("vol->index_record_size = %i (0x%x)",
  			vol->index_record_size, vol->index_record_size);
  	ntfs_debug("vol->index_record_size_mask = 0x%x",
  			vol->index_record_size_mask);
  	ntfs_debug("vol->index_record_size_bits = %i (0x%x)",
  			vol->index_record_size_bits,
  			vol->index_record_size_bits);

  	/* We cannot support index record sizes below the sector size. */
  	if (vol->index_record_size < vol->sector_size) {
  		ntfs_error(vol->sb, "Index record size (%i) is smaller than "
  				"the sector size (%i).  This is not "
  				"supported.  Sorry.", vol->index_record_size,
  				vol->sector_size);

  		return false;

  	}

  	/*
  	 * Get the size of the volume in clusters and check for 64-bit-ness.
  	 * Windows currently only uses 32 bits to save the clusters so we do
  	 * the same as it is much faster on 32-bit CPUs.
  	 */
  	ll = sle64_to_cpu(b->number_of_sectors) >> sectors_per_cluster_bits;
  	if ((u64)ll >= 1ULL << 32) {
  		ntfs_error(vol->sb, "Cannot handle 64-bit clusters.  Sorry.");

  		return false;

  	}
  	vol->nr_clusters = ll;
  	ntfs_debug("vol->nr_clusters = 0x%llx", (long long)vol->nr_clusters);
  	/*
  	 * On an architecture where unsigned long is 32-bits, we restrict the
  	 * volume size to 2TiB (2^41). On a 64-bit architecture, the compiler
  	 * will hopefully optimize the whole check away.
  	 */
  	if (sizeof(unsigned long) < 8) {
  		if ((ll << vol->cluster_size_bits) >= (1ULL << 41)) {
  			ntfs_error(vol->sb, "Volume size (%lluTiB) is too "
  					"large for this architecture.  "
  					"Maximum supported is 2TiB.  Sorry.",
  					(unsigned long long)ll >> (40 -
  					vol->cluster_size_bits));

  			return false;

  		}
  	}
  	ll = sle64_to_cpu(b->mft_lcn);
  	if (ll >= vol->nr_clusters) {

  		ntfs_error(vol->sb, "MFT LCN (%lli, 0x%llx) is beyond end of "
  				"volume.  Weird.", (unsigned long long)ll,
  				(unsigned long long)ll);

  		return false;

  	}
  	vol->mft_lcn = ll;
  	ntfs_debug("vol->mft_lcn = 0x%llx", (long long)vol->mft_lcn);
  	ll = sle64_to_cpu(b->mftmirr_lcn);
  	if (ll >= vol->nr_clusters) {

  		ntfs_error(vol->sb, "MFTMirr LCN (%lli, 0x%llx) is beyond end "
  				"of volume.  Weird.", (unsigned long long)ll,
  				(unsigned long long)ll);

  		return false;

  	}
  	vol->mftmirr_lcn = ll;
  	ntfs_debug("vol->mftmirr_lcn = 0x%llx", (long long)vol->mftmirr_lcn);
  #ifdef NTFS_RW
  	/*
  	 * 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);
  #endif /* NTFS_RW */
  	vol->serial_no = le64_to_cpu(b->volume_serial_number);
  	ntfs_debug("vol->serial_no = 0x%llx",
  			(unsigned long long)vol->serial_no);

  	return true;

  }
  
  /**
   * ntfs_setup_allocators - initialize the cluster and mft allocators
   * @vol:	volume structure for which to setup the allocators
   *
   * Setup the cluster (lcn) and mft allocators to the starting values.
   */
  static void ntfs_setup_allocators(ntfs_volume *vol)
  {
  #ifdef NTFS_RW
  	LCN mft_zone_size, mft_lcn;
  #endif /* NTFS_RW */
  
  	ntfs_debug("vol->mft_zone_multiplier = 0x%x",
  			vol->mft_zone_multiplier);
  #ifdef NTFS_RW
  	/* Determine the size of the MFT zone. */
  	mft_zone_size = vol->nr_clusters;
  	switch (vol->mft_zone_multiplier) {  /* % of volume size in clusters */
  	case 4:
  		mft_zone_size >>= 1;			/* 50%   */
  		break;
  	case 3:
  		mft_zone_size = (mft_zone_size +
  				(mft_zone_size >> 1)) >> 2;	/* 37.5% */
  		break;
  	case 2:
  		mft_zone_size >>= 2;			/* 25%   */
  		break;
  	/* case 1: */
  	default:
  		mft_zone_size >>= 3;			/* 12.5% */
  		break;
  	}
  	/* Setup the mft zone. */
  	vol->mft_zone_start = vol->mft_zone_pos = vol->mft_lcn;
  	ntfs_debug("vol->mft_zone_pos = 0x%llx",
  			(unsigned long long)vol->mft_zone_pos);
  	/*
  	 * Calculate the mft_lcn for an unmodified NTFS volume (see mkntfs
  	 * source) and if the actual mft_lcn is in the expected place or even
  	 * further to the front of the volume, extend the mft_zone to cover the
  	 * beginning of the volume as well.  This is in order to protect the
  	 * area reserved for the mft bitmap as well within the mft_zone itself.
  	 * On non-standard volumes we do not protect it as the overhead would
  	 * be higher than the speed increase we would get by doing it.
  	 */
  	mft_lcn = (8192 + 2 * vol->cluster_size - 1) / vol->cluster_size;
  	if (mft_lcn * vol->cluster_size < 16 * 1024)
  		mft_lcn = (16 * 1024 + vol->cluster_size - 1) /
  				vol->cluster_size;
  	if (vol->mft_zone_start <= mft_lcn)
  		vol->mft_zone_start = 0;
  	ntfs_debug("vol->mft_zone_start = 0x%llx",
  			(unsigned long long)vol->mft_zone_start);
  	/*
  	 * Need to cap the mft zone on non-standard volumes so that it does
  	 * not point outside the boundaries of the volume.  We do this by
  	 * halving the zone size until we are inside the volume.
  	 */
  	vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
  	while (vol->mft_zone_end >= vol->nr_clusters) {
  		mft_zone_size >>= 1;
  		vol->mft_zone_end = vol->mft_lcn + mft_zone_size;
  	}
  	ntfs_debug("vol->mft_zone_end = 0x%llx",
  			(unsigned long long)vol->mft_zone_end);
  	/*
  	 * Set the current position within each data zone to the start of the
  	 * respective zone.
  	 */
  	vol->data1_zone_pos = vol->mft_zone_end;
  	ntfs_debug("vol->data1_zone_pos = 0x%llx",
  			(unsigned long long)vol->data1_zone_pos);
  	vol->data2_zone_pos = 0;
  	ntfs_debug("vol->data2_zone_pos = 0x%llx",
  			(unsigned long long)vol->data2_zone_pos);
  
  	/* Set the mft data allocation position to mft record 24. */
  	vol->mft_data_pos = 24;
  	ntfs_debug("vol->mft_data_pos = 0x%llx",
  			(unsigned long long)vol->mft_data_pos);
  #endif /* NTFS_RW */
  }
  
  #ifdef NTFS_RW
  
  /**
   * load_and_init_mft_mirror - load and setup the mft mirror inode for a volume
   * @vol:	ntfs super block describing device whose mft mirror to load
   *

   * Return 'true' on success or 'false' on error.

   */

  static bool load_and_init_mft_mirror(ntfs_volume *vol)

  {
  	struct inode *tmp_ino;
  	ntfs_inode *tmp_ni;
  
  	ntfs_debug("Entering.");
  	/* Get mft mirror inode. */
  	tmp_ino = ntfs_iget(vol->sb, FILE_MFTMirr);
  	if (IS_ERR(tmp_ino) || is_bad_inode(tmp_ino)) {
  		if (!IS_ERR(tmp_ino))
  			iput(tmp_ino);
  		/* Caller will display error message. */

  		return false;

  	}
  	/*
  	 * Re-initialize some specifics about $MFTMirr's inode as
  	 * ntfs_read_inode() will have set up the default ones.
  	 */
  	/* Set uid and gid to root. */

  	tmp_ino->i_uid = GLOBAL_ROOT_UID;
  	tmp_ino->i_gid = GLOBAL_ROOT_GID;

  	/* Regular file.  No access for anyone. */
  	tmp_ino->i_mode = S_IFREG;
  	/* No VFS initiated operations allowed for $MFTMirr. */
  	tmp_ino->i_op = &ntfs_empty_inode_ops;
  	tmp_ino->i_fop = &ntfs_empty_file_ops;
  	/* Put in our special address space operations. */
  	tmp_ino->i_mapping->a_ops = &ntfs_mst_aops;
  	tmp_ni = NTFS_I(tmp_ino);
  	/* The $MFTMirr, like the $MFT is multi sector transfer protected. */
  	NInoSetMstProtected(tmp_ni);

  	NInoSetSparseDisabled(tmp_ni);

  	/*
  	 * Set up our little cheat allowing us to reuse the async read io
  	 * completion handler for directories.
  	 */
  	tmp_ni->itype.index.block_size = vol->mft_record_size;
  	tmp_ni->itype.index.block_size_bits = vol->mft_record_size_bits;
  	vol->mftmirr_ino = tmp_ino;
  	ntfs_debug("Done.");

  	return true;

  }
  
  /**
   * check_mft_mirror - compare contents of the mft mirror with the mft
   * @vol:	ntfs super block describing device whose mft mirror to check
   *

   * Return 'true' on success or 'false' on error.

   *
   * Note, this function also results in the mft mirror runlist being completely
   * mapped into memory.  The mft mirror write code requires this and will BUG()
   * should it find an unmapped runlist element.
   */

  static bool check_mft_mirror(ntfs_volume *vol)

  {

  	struct super_block *sb = vol->sb;
  	ntfs_inode *mirr_ni;
  	struct page *mft_page, *mirr_page;
  	u8 *kmft, *kmirr;
  	runlist_element *rl, rl2[2];

  	pgoff_t index;

  	int mrecs_per_page, i;
  
  	ntfs_debug("Entering.");
  	/* Compare contents of $MFT and $MFTMirr. */

  	mrecs_per_page = PAGE_SIZE / vol->mft_record_size;

  	BUG_ON(!mrecs_per_page);
  	BUG_ON(!vol->mftmirr_size);
  	mft_page = mirr_page = NULL;
  	kmft = kmirr = NULL;
  	index = i = 0;
  	do {
  		u32 bytes;
  
  		/* Switch pages if necessary. */
  		if (!(i % mrecs_per_page)) {
  			if (index) {
  				ntfs_unmap_page(mft_page);
  				ntfs_unmap_page(mirr_page);
  			}
  			/* Get the $MFT page. */
  			mft_page = ntfs_map_page(vol->mft_ino->i_mapping,
  					index);
  			if (IS_ERR(mft_page)) {
  				ntfs_error(sb, "Failed to read $MFT.");

  				return false;

  			}
  			kmft = page_address(mft_page);
  			/* Get the $MFTMirr page. */
  			mirr_page = ntfs_map_page(vol->mftmirr_ino->i_mapping,
  					index);
  			if (IS_ERR(mirr_page)) {
  				ntfs_error(sb, "Failed to read $MFTMirr.");
  				goto mft_unmap_out;
  			}
  			kmirr = page_address(mirr_page);
  			++index;
  		}

  		/* Do not check the record if it is not in use. */
  		if (((MFT_RECORD*)kmft)->flags & MFT_RECORD_IN_USE) {
  			/* Make sure the record is ok. */
  			if (ntfs_is_baad_recordp((le32*)kmft)) {
  				ntfs_error(sb, "Incomplete multi sector "
  						"transfer detected in mft "
  						"record %i.", i);

  mm_unmap_out:

  				ntfs_unmap_page(mirr_page);

  mft_unmap_out:

  				ntfs_unmap_page(mft_page);

  				return false;

  			}

  		}

  		/* Do not check the mirror record if it is not in use. */
  		if (((MFT_RECORD*)kmirr)->flags & MFT_RECORD_IN_USE) {
  			if (ntfs_is_baad_recordp((le32*)kmirr)) {
  				ntfs_error(sb, "Incomplete multi sector "
  						"transfer detected in mft "
  						"mirror record %i.", i);
  				goto mm_unmap_out;
  			}

  		}
  		/* Get the amount of data in the current record. */
  		bytes = le32_to_cpu(((MFT_RECORD*)kmft)->bytes_in_use);

  		if (bytes < sizeof(MFT_RECORD_OLD) ||
  				bytes > vol->mft_record_size ||
  				ntfs_is_baad_recordp((le32*)kmft)) {

  			bytes = le32_to_cpu(((MFT_RECORD*)kmirr)->bytes_in_use);

  			if (bytes < sizeof(MFT_RECORD_OLD) ||
  					bytes > vol->mft_record_size ||
  					ntfs_is_baad_recordp((le32*)kmirr))

  				bytes = vol->mft_record_size;
  		}
  		/* Compare the two records. */
  		if (memcmp(kmft, kmirr, bytes)) {
  			ntfs_error(sb, "$MFT and $MFTMirr (record %i) do not "
  					"match.  Run ntfsfix or chkdsk.", i);
  			goto mm_unmap_out;
  		}
  		kmft += vol->mft_record_size;
  		kmirr += vol->mft_record_size;
  	} while (++i < vol->mftmirr_size);
  	/* Release the last pages. */
  	ntfs_unmap_page(mft_page);
  	ntfs_unmap_page(mirr_page);
  
  	/* Construct the mft mirror runlist by hand. */
  	rl2[0].vcn = 0;
  	rl2[0].lcn = vol->mftmirr_lcn;
  	rl2[0].length = (vol->mftmirr_size * vol->mft_record_size +
  			vol->cluster_size - 1) / vol->cluster_size;
  	rl2[1].vcn = rl2[0].length;
  	rl2[1].lcn = LCN_ENOENT;
  	rl2[1].length = 0;
  	/*
  	 * Because we have just read all of the mft mirror, we know we have
  	 * mapped the full runlist for it.
  	 */
  	mirr_ni = NTFS_I(vol->mftmirr_ino);
  	down_read(&mirr_ni->runlist.lock);
  	rl = mirr_ni->runlist.rl;
  	/* Compare the two runlists.  They must be identical. */
  	i = 0;
  	do {
  		if (rl2[i].vcn != rl[i].vcn || rl2[i].lcn != rl[i].lcn ||
  				rl2[i].length != rl[i].length) {
  			ntfs_error(sb, "$MFTMirr location mismatch.  "
  					"Run chkdsk.");
  			up_read(&mirr_ni->runlist.lock);

  			return false;

  		}
  	} while (rl2[i++].length);
  	up_read(&mirr_ni->runlist.lock);
  	ntfs_debug("Done.");

  	return true;

  }
  
  /**
   * load_and_check_logfile - load and check the logfile inode for a volume
   * @vol:	ntfs super block describing device whose logfile to load
   *

   * Return 'true' on success or 'false' on error.

   */

  static bool load_and_check_logfile(ntfs_volume *vol,

  		RESTART_PAGE_HEADER **rp)

  {
  	struct inode *tmp_ino;
  
  	ntfs_debug("Entering.");
  	tmp_ino = ntfs_iget(vol->sb, FILE_LogFile);
  	if (IS_ERR(tmp_ino) || is_bad_inode(tmp_ino)) {
  		if (!IS_ERR(tmp_ino))
  			iput(tmp_ino);
  		/* Caller will display error message. */

  		return false;

  	}

  	if (!ntfs_check_logfile(tmp_ino, rp)) {

  		iput(tmp_ino);
  		/* ntfs_check_logfile() will have displayed error output. */

  		return false;

  	}

  	NInoSetSparseDisabled(NTFS_I(tmp_ino));

  	vol->logfile_ino = tmp_ino;
  	ntfs_debug("Done.");

  	return true;

  }

  #define NTFS_HIBERFIL_HEADER_SIZE	4096
  
  /**
   * check_windows_hibernation_status - check if Windows is suspended on a volume
   * @vol:	ntfs super block of device to check
   *
   * Check if Windows is hibernated on the ntfs volume @vol.  This is done by
   * looking for the file hiberfil.sys in the root directory of the volume.  If
   * the file is not present Windows is definitely not suspended.
   *
   * If hiberfil.sys exists and is less than 4kiB in size it means Windows is
   * definitely suspended (this volume is not the system volume).  Caveat:  on a
   * system with many volumes it is possible that the < 4kiB check is bogus but
   * for now this should do fine.
   *
   * If hiberfil.sys exists and is larger than 4kiB in size, we need to read the
   * hiberfil header (which is the first 4kiB).  If this begins with "hibr",
   * Windows is definitely suspended.  If it is completely full of zeroes,
   * Windows is definitely not hibernated.  Any other case is treated as if
   * Windows is suspended.  This caters for the above mentioned caveat of a
   * system with many volumes where no "hibr" magic would be present and there is
   * no zero header.
   *
   * Return 0 if Windows is not hibernated on the volume, >0 if Windows is
   * hibernated on the volume, and -errno on error.
   */
  static int check_windows_hibernation_status(ntfs_volume *vol)
  {
  	MFT_REF mref;
  	struct inode *vi;

  	struct page *page;
  	u32 *kaddr, *kend;
  	ntfs_name *name = NULL;
  	int ret = 1;

  	static const ntfschar hiberfil[13] = { cpu_to_le16('h'),
  			cpu_to_le16('i'), cpu_to_le16('b'),
  			cpu_to_le16('e'), cpu_to_le16('r'),
  			cpu_to_le16('f'), cpu_to_le16('i'),
  			cpu_to_le16('l'), cpu_to_le16('.'),
  			cpu_to_le16('s'), cpu_to_le16('y'),
  			cpu_to_le16('s'), 0 };

  
  	ntfs_debug("Entering.");
  	/*
  	 * Find the inode number for the hibernation file by looking up the
  	 * filename hiberfil.sys in the root directory.
  	 */

  	inode_lock(vol->root_ino);

  	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->root_ino), hiberfil, 12,
  			&name);

  	inode_unlock(vol->root_ino);

  	if (IS_ERR_MREF(mref)) {
  		ret = MREF_ERR(mref);
  		/* If the file does not exist, Windows is not hibernated. */
  		if (ret == -ENOENT) {
  			ntfs_debug("hiberfil.sys not present.  Windows is not "
  					"hibernated on the volume.");
  			return 0;
  		}

  		/* A real error occurred. */

  		ntfs_error(vol->sb, "Failed to find inode number for "
  				"hiberfil.sys.");
  		return ret;
  	}
  	/* We do not care for the type of match that was found. */
  	kfree(name);
  	/* Get the inode. */
  	vi = ntfs_iget(vol->sb, MREF(mref));
  	if (IS_ERR(vi) || is_bad_inode(vi)) {
  		if (!IS_ERR(vi))
  			iput(vi);
  		ntfs_error(vol->sb, "Failed to load hiberfil.sys.");
  		return IS_ERR(vi) ? PTR_ERR(vi) : -EIO;
  	}
  	if (unlikely(i_size_read(vi) < NTFS_HIBERFIL_HEADER_SIZE)) {
  		ntfs_debug("hiberfil.sys is smaller than 4kiB (0x%llx).  "
  				"Windows is hibernated on the volume.  This "
  				"is not the system volume.", i_size_read(vi));
  		goto iput_out;
  	}

  	page = ntfs_map_page(vi->i_mapping, 0);
  	if (IS_ERR(page)) {
  		ntfs_error(vol->sb, "Failed to read from hiberfil.sys.");
  		ret = PTR_ERR(page);
  		goto iput_out;
  	}
  	kaddr = (u32*)page_address(page);

  	if (*(le32*)kaddr == cpu_to_le32(0x72626968)/*'hibr'*/) {

  		ntfs_debug("Magic \"hibr\" found in hiberfil.sys.  Windows is "
  				"hibernated on the volume.  This is the "
  				"system volume.");
  		goto unm_iput_out;
  	}
  	kend = kaddr + NTFS_HIBERFIL_HEADER_SIZE/sizeof(*kaddr);
  	do {
  		if (unlikely(*kaddr)) {
  			ntfs_debug("hiberfil.sys is larger than 4kiB "
  					"(0x%llx), does not contain the "
  					"\"hibr\" magic, and does not have a "
  					"zero header.  Windows is hibernated "
  					"on the volume.  This is not the "
  					"system volume.", i_size_read(vi));
  			goto unm_iput_out;
  		}
  	} while (++kaddr < kend);
  	ntfs_debug("hiberfil.sys contains a zero header.  Windows is not "
  			"hibernated on the volume.  This is the system "
  			"volume.");
  	ret = 0;
  unm_iput_out:
  	ntfs_unmap_page(page);
  iput_out:
  	iput(vi);
  	return ret;
  }

  /**
   * load_and_init_quota - load and setup the quota file for a volume if present
   * @vol:	ntfs super block describing device whose quota file to load
   *

   * Return 'true' on success or 'false' on error.  If $Quota is not present, we

   * leave vol->quota_ino as NULL and return success.
   */

  static bool load_and_init_quota(ntfs_volume *vol)

  {
  	MFT_REF mref;
  	struct inode *tmp_ino;
  	ntfs_name *name = NULL;

  	static const ntfschar Quota[7] = { cpu_to_le16('$'),
  			cpu_to_le16('Q'), cpu_to_le16('u'),
  			cpu_to_le16('o'), cpu_to_le16('t'),
  			cpu_to_le16('a'), 0 };
  	static ntfschar Q[3] = { cpu_to_le16('$'),
  			cpu_to_le16('Q'), 0 };

  
  	ntfs_debug("Entering.");
  	/*
  	 * Find the inode number for the quota file by looking up the filename
  	 * $Quota in the extended system files directory $Extend.
  	 */

  	inode_lock(vol->extend_ino);

  	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->extend_ino), Quota, 6,
  			&name);

  	inode_unlock(vol->extend_ino);

  	if (IS_ERR_MREF(mref)) {
  		/*
  		 * If the file does not exist, quotas are disabled and have
  		 * never been enabled on this volume, just return success.
  		 */
  		if (MREF_ERR(mref) == -ENOENT) {
  			ntfs_debug("$Quota not present.  Volume does not have "
  					"quotas enabled.");
  			/*
  			 * No need to try to set quotas out of date if they are
  			 * not enabled.
  			 */
  			NVolSetQuotaOutOfDate(vol);

  			return true;

  		}

  		/* A real error occurred. */

  		ntfs_error(vol->sb, "Failed to find inode number for $Quota.");

  		return false;

  	}
  	/* We do not care for the type of match that was found. */

  	kfree(name);

  	/* Get the inode. */
  	tmp_ino = ntfs_iget(vol->sb, MREF(mref));
  	if (IS_ERR(tmp_ino) || is_bad_inode(tmp_ino)) {
  		if (!IS_ERR(tmp_ino))
  			iput(tmp_ino);
  		ntfs_error(vol->sb, "Failed to load $Quota.");

  		return false;

  	}
  	vol->quota_ino = tmp_ino;
  	/* Get the $Q index allocation attribute. */
  	tmp_ino = ntfs_index_iget(vol->quota_ino, Q, 2);
  	if (IS_ERR(tmp_ino)) {
  		ntfs_error(vol->sb, "Failed to load $Quota/$Q index.");

  		return false;

  	}
  	vol->quota_q_ino = tmp_ino;
  	ntfs_debug("Done.");

  	return true;

  }
  
  /**

   * load_and_init_usnjrnl - load and setup the transaction log if present
   * @vol:	ntfs super block describing device whose usnjrnl file to load
   *

   * Return 'true' on success or 'false' on error.

   *
   * If $UsnJrnl is not present or in the process of being disabled, we set
   * NVolUsnJrnlStamped() and return success.
   *
   * If the $UsnJrnl $DATA/$J attribute has a size equal to the lowest valid usn,
   * i.e. transaction logging has only just been enabled or the journal has been
   * stamped and nothing has been logged since, we also set NVolUsnJrnlStamped()
   * and return success.
   */

  static bool load_and_init_usnjrnl(ntfs_volume *vol)

  {
  	MFT_REF mref;
  	struct inode *tmp_ino;
  	ntfs_inode *tmp_ni;
  	struct page *page;
  	ntfs_name *name = NULL;
  	USN_HEADER *uh;

  	static const ntfschar UsnJrnl[9] = { cpu_to_le16('$'),
  			cpu_to_le16('U'), cpu_to_le16('s'),
  			cpu_to_le16('n'), cpu_to_le16('J'),
  			cpu_to_le16('r'), cpu_to_le16('n'),
  			cpu_to_le16('l'), 0 };
  	static ntfschar Max[5] = { cpu_to_le16('$'),
  			cpu_to_le16('M'), cpu_to_le16('a'),
  			cpu_to_le16('x'), 0 };
  	static ntfschar J[3] = { cpu_to_le16('$'),
  			cpu_to_le16('J'), 0 };

  
  	ntfs_debug("Entering.");
  	/*
  	 * Find the inode number for the transaction log file by looking up the
  	 * filename $UsnJrnl in the extended system files directory $Extend.
  	 */

  	inode_lock(vol->extend_ino);

  	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->extend_ino), UsnJrnl, 8,
  			&name);

  	inode_unlock(vol->extend_ino);

  	if (IS_ERR_MREF(mref)) {
  		/*
  		 * If the file does not exist, transaction logging is disabled,
  		 * just return success.
  		 */
  		if (MREF_ERR(mref) == -ENOENT) {
  			ntfs_debug("$UsnJrnl not present.  Volume does not "
  					"have transaction logging enabled.");
  not_enabled:
  			/*
  			 * No need to try to stamp the transaction log if
  			 * transaction logging is not enabled.
  			 */
  			NVolSetUsnJrnlStamped(vol);

  			return true;

  		}

  		/* A real error occurred. */

  		ntfs_error(vol->sb, "Failed to find inode number for "
  				"$UsnJrnl.");

  		return false;

  	}
  	/* We do not care for the type of match that was found. */
  	kfree(name);
  	/* Get the inode. */
  	tmp_ino = ntfs_iget(vol->sb, MREF(mref));

  	if (IS_ERR(tmp_ino) || unlikely(is_bad_inode(tmp_ino))) {

  		if (!IS_ERR(tmp_ino))
  			iput(tmp_ino);
  		ntfs_error(vol->sb, "Failed to load $UsnJrnl.");

  		return false;

  	}
  	vol->usnjrnl_ino = tmp_ino;
  	/*
  	 * If the transaction log is in the process of being deleted, we can
  	 * ignore it.
  	 */
  	if (unlikely(vol->vol_flags & VOLUME_DELETE_USN_UNDERWAY)) {
  		ntfs_debug("$UsnJrnl in the process of being disabled.  "
  				"Volume does not have transaction logging "
  				"enabled.");
  		goto not_enabled;
  	}
  	/* Get the $DATA/$Max attribute. */
  	tmp_ino = ntfs_attr_iget(vol->usnjrnl_ino, AT_DATA, Max, 4);
  	if (IS_ERR(tmp_ino)) {
  		ntfs_error(vol->sb, "Failed to load $UsnJrnl/$DATA/$Max "
  				"attribute.");

  		return false;

  	}
  	vol->usnjrnl_max_ino = tmp_ino;
  	if (unlikely(i_size_read(tmp_ino) < sizeof(USN_HEADER))) {
  		ntfs_error(vol->sb, "Found corrupt $UsnJrnl/$DATA/$Max "
  				"attribute (size is 0x%llx but should be at "

  				"least 0x%zx bytes).", i_size_read(tmp_ino),

  				sizeof(USN_HEADER));

  		return false;

  	}
  	/* Get the $DATA/$J attribute. */
  	tmp_ino = ntfs_attr_iget(vol->usnjrnl_ino, AT_DATA, J, 2);
  	if (IS_ERR(tmp_ino)) {
  		ntfs_error(vol->sb, "Failed to load $UsnJrnl/$DATA/$J "
  				"attribute.");

  		return false;

  	}
  	vol->usnjrnl_j_ino = tmp_ino;
  	/* Verify $J is non-resident and sparse. */
  	tmp_ni = NTFS_I(vol->usnjrnl_j_ino);
  	if (unlikely(!NInoNonResident(tmp_ni) || !NInoSparse(tmp_ni))) {
  		ntfs_error(vol->sb, "$UsnJrnl/$DATA/$J attribute is resident "
  				"and/or not sparse.");

  		return false;

  	}
  	/* Read the USN_HEADER from $DATA/$Max. */
  	page = ntfs_map_page(vol->usnjrnl_max_ino->i_mapping, 0);
  	if (IS_ERR(page)) {
  		ntfs_error(vol->sb, "Failed to read from $UsnJrnl/$DATA/$Max "
  				"attribute.");

  		return false;

  	}
  	uh = (USN_HEADER*)page_address(page);
  	/* Sanity check the $Max. */
  	if (unlikely(sle64_to_cpu(uh->allocation_delta) >
  			sle64_to_cpu(uh->maximum_size))) {
  		ntfs_error(vol->sb, "Allocation delta (0x%llx) exceeds "
  				"maximum size (0x%llx).  $UsnJrnl is corrupt.",
  				(long long)sle64_to_cpu(uh->allocation_delta),
  				(long long)sle64_to_cpu(uh->maximum_size));
  		ntfs_unmap_page(page);

  		return false;

  	}
  	/*
  	 * If the transaction log has been stamped and nothing has been written
  	 * to it since, we do not need to stamp it.
  	 */
  	if (unlikely(sle64_to_cpu(uh->lowest_valid_usn) >=
  			i_size_read(vol->usnjrnl_j_ino))) {
  		if (likely(sle64_to_cpu(uh->lowest_valid_usn) ==
  				i_size_read(vol->usnjrnl_j_ino))) {
  			ntfs_unmap_page(page);
  			ntfs_debug("$UsnJrnl is enabled but nothing has been "
  					"logged since it was last stamped.  "
  					"Treating this as if the volume does "
  					"not have transaction logging "
  					"enabled.");
  			goto not_enabled;
  		}
  		ntfs_error(vol->sb, "$UsnJrnl has lowest valid usn (0x%llx) "
  				"which is out of bounds (0x%llx).  $UsnJrnl "
  				"is corrupt.",
  				(long long)sle64_to_cpu(uh->lowest_valid_usn),
  				i_size_read(vol->usnjrnl_j_ino));
  		ntfs_unmap_page(page);

  		return false;

  	}
  	ntfs_unmap_page(page);
  	ntfs_debug("Done.");

  	return true;

  }
  
  /**

   * load_and_init_attrdef - load the attribute definitions table for a volume
   * @vol:	ntfs super block describing device whose attrdef to load
   *

   * Return 'true' on success or 'false' on error.

   */

  static bool load_and_init_attrdef(ntfs_volume *vol)

  {

  	loff_t i_size;

  	struct super_block *sb = vol->sb;
  	struct inode *ino;
  	struct page *page;

  	pgoff_t index, max_index;

  	unsigned int size;
  
  	ntfs_debug("Entering.");
  	/* Read attrdef table and setup vol->attrdef and vol->attrdef_size. */
  	ino = ntfs_iget(sb, FILE_AttrDef);
  	if (IS_ERR(ino) || is_bad_inode(ino)) {
  		if (!IS_ERR(ino))
  			iput(ino);
  		goto failed;
  	}

  	NInoSetSparseDisabled(NTFS_I(ino));

  	/* The size of FILE_AttrDef must be above 0 and fit inside 31 bits. */

  	i_size = i_size_read(ino);
  	if (i_size <= 0 || i_size > 0x7fffffff)

  		goto iput_failed;

  	vol->attrdef = (ATTR_DEF*)ntfs_malloc_nofs(i_size);

  	if (!vol->attrdef)
  		goto iput_failed;
  	index = 0;

  	max_index = i_size >> PAGE_SHIFT;
  	size = PAGE_SIZE;

  	while (index < max_index) {
  		/* Read the attrdef table and copy it into the linear buffer. */
  read_partial_attrdef_page:
  		page = ntfs_map_page(ino->i_mapping, index);
  		if (IS_ERR(page))
  			goto free_iput_failed;

  		memcpy((u8*)vol->attrdef + (index++ << PAGE_SHIFT),

  				page_address(page), size);
  		ntfs_unmap_page(page);
  	};

  	if (size == PAGE_SIZE) {
  		size = i_size & ~PAGE_MASK;

  		if (size)
  			goto read_partial_attrdef_page;
  	}

  	vol->attrdef_size = i_size;
  	ntfs_debug("Read %llu bytes from $AttrDef.", i_size);

  	iput(ino);

  	return true;

  free_iput_failed:
  	ntfs_free(vol->attrdef);
  	vol->attrdef = NULL;
  iput_failed:
  	iput(ino);
  failed:
  	ntfs_error(sb, "Failed to initialize attribute definition table.");

  	return false;

  }
  
  #endif /* NTFS_RW */
  
  /**
   * load_and_init_upcase - load the upcase table for an ntfs volume
   * @vol:	ntfs super block describing device whose upcase to load
   *

   * Return 'true' on success or 'false' on error.

   */

  static bool load_and_init_upcase(ntfs_volume *vol)

  {

  	loff_t i_size;

  	struct super_block *sb = vol->sb;
  	struct inode *ino;
  	struct page *page;

  	pgoff_t index, max_index;

  	unsigned int size;
  	int i, max;
  
  	ntfs_debug("Entering.");
  	/* Read upcase table and setup vol->upcase and vol->upcase_len. */
  	ino = ntfs_iget(sb, FILE_UpCase);
  	if (IS_ERR(ino) || is_bad_inode(ino)) {
  		if (!IS_ERR(ino))
  			iput(ino);
  		goto upcase_failed;
  	}
  	/*
  	 * The upcase size must not be above 64k Unicode characters, must not
  	 * be zero and must be a multiple of sizeof(ntfschar).
  	 */

  	i_size = i_size_read(ino);
  	if (!i_size || i_size & (sizeof(ntfschar) - 1) ||
  			i_size > 64ULL * 1024 * sizeof(ntfschar))

  		goto iput_upcase_failed;

  	vol->upcase = (ntfschar*)ntfs_malloc_nofs(i_size);

  	if (!vol->upcase)
  		goto iput_upcase_failed;
  	index = 0;

  	max_index = i_size >> PAGE_SHIFT;
  	size = PAGE_SIZE;

  	while (index < max_index) {
  		/* Read the upcase table and copy it into the linear buffer. */
  read_partial_upcase_page:
  		page = ntfs_map_page(ino->i_mapping, index);
  		if (IS_ERR(page))
  			goto iput_upcase_failed;

  		memcpy((char*)vol->upcase + (index++ << PAGE_SHIFT),

  				page_address(page), size);
  		ntfs_unmap_page(page);
  	};

  	if (size == PAGE_SIZE) {
  		size = i_size & ~PAGE_MASK;

  		if (size)
  			goto read_partial_upcase_page;
  	}

  	vol->upcase_len = i_size >> UCHAR_T_SIZE_BITS;

  	ntfs_debug("Read %llu bytes from $UpCase (expected %zu bytes).",

  			i_size, 64 * 1024 * sizeof(ntfschar));

  	iput(ino);

  	mutex_lock(&ntfs_lock);

  	if (!default_upcase) {
  		ntfs_debug("Using volume specified $UpCase since default is "
  				"not present.");

  		mutex_unlock(&ntfs_lock);

  		return true;

  	}
  	max = default_upcase_len;
  	if (max > vol->upcase_len)
  		max = vol->upcase_len;
  	for (i = 0; i < max; i++)
  		if (vol->upcase[i] != default_upcase[i])
  			break;
  	if (i == max) {
  		ntfs_free(vol->upcase);
  		vol->upcase = default_upcase;
  		vol->upcase_len = max;
  		ntfs_nr_upcase_users++;

  		mutex_unlock(&ntfs_lock);

  		ntfs_debug("Volume specified $UpCase matches default. Using "
  				"default.");

  		return true;

  	}

  	mutex_unlock(&ntfs_lock);

  	ntfs_debug("Using volume specified $UpCase since it does not match "
  			"the default.");

  	return true;

  iput_upcase_failed:
  	iput(ino);
  	ntfs_free(vol->upcase);
  	vol->upcase = NULL;
  upcase_failed:

  	mutex_lock(&ntfs_lock);

  	if (default_upcase) {
  		vol->upcase = default_upcase;
  		vol->upcase_len = default_upcase_len;
  		ntfs_nr_upcase_users++;

  		mutex_unlock(&ntfs_lock);

  		ntfs_error(sb, "Failed to load $UpCase from the volume. Using "
  				"default.");

  		return true;

  	}

  	mutex_unlock(&ntfs_lock);

  	ntfs_error(sb, "Failed to initialize upcase table.");

  	return false;

  }

  /*
   * The lcn and mft bitmap inodes are NTFS-internal inodes with
   * their own special locking rules:
   */
  static struct lock_class_key
  	lcnbmp_runlist_lock_key, lcnbmp_mrec_lock_key,
  	mftbmp_runlist_lock_key, mftbmp_mrec_lock_key;

  /**
   * load_system_files - open the system files using normal functions
   * @vol:	ntfs super block describing device whose system files to load
   *
   * Open the system files with normal access functions and complete setting up
   * the ntfs super block @vol.
   *

   * Return 'true' on success or 'false' on error.

   */

  static bool load_system_files(ntfs_volume *vol)

  {
  	struct super_block *sb = vol->sb;
  	MFT_RECORD *m;
  	VOLUME_INFORMATION *vi;
  	ntfs_attr_search_ctx *ctx;

  #ifdef NTFS_RW

  	RESTART_PAGE_HEADER *rp;

  	int err;
  #endif /* NTFS_RW */

  
  	ntfs_debug("Entering.");
  #ifdef NTFS_RW
  	/* Get mft mirror inode compare the contents of $MFT and $MFTMirr. */
  	if (!load_and_init_mft_mirror(vol) || !check_mft_mirror(vol)) {
  		static const char *es1 = "Failed to load $MFTMirr";
  		static const char *es2 = "$MFTMirr does not match $MFT";
  		static const char *es3 = ".  Run ntfsfix and/or chkdsk.";
  
  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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",
  						!vol->mftmirr_ino ? es1 : es2,
  						es3);
  				goto iput_mirr_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s",
  					!vol->mftmirr_ino ? es1 : es2, es3);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s",
  					!vol->mftmirr_ino ? es1 : es2, es3);
  		/* This will prevent a read-write remount. */
  		NVolSetErrors(vol);
  	}
  #endif /* NTFS_RW */
  	/* Get mft bitmap attribute inode. */
  	vol->mftbmp_ino = ntfs_attr_iget(vol->mft_ino, AT_BITMAP, NULL, 0);
  	if (IS_ERR(vol->mftbmp_ino)) {
  		ntfs_error(sb, "Failed to load $MFT/$BITMAP attribute.");
  		goto iput_mirr_err_out;
  	}

  	lockdep_set_class(&NTFS_I(vol->mftbmp_ino)->runlist.lock,
  			   &mftbmp_runlist_lock_key);
  	lockdep_set_class(&NTFS_I(vol->mftbmp_ino)->mrec_lock,
  			   &mftbmp_mrec_lock_key);

  	/* Read upcase table and setup @vol->upcase and @vol->upcase_len. */
  	if (!load_and_init_upcase(vol))
  		goto iput_mftbmp_err_out;
  #ifdef NTFS_RW
  	/*
  	 * Read attribute definitions table and setup @vol->attrdef and
  	 * @vol->attrdef_size.
  	 */
  	if (!load_and_init_attrdef(vol))
  		goto iput_upcase_err_out;
  #endif /* NTFS_RW */
  	/*
  	 * Get the cluster allocation bitmap inode and verify the size, no
  	 * need for any locking at this stage as we are already running
  	 * exclusively as we are mount in progress task.
  	 */
  	vol->lcnbmp_ino = ntfs_iget(sb, FILE_Bitmap);
  	if (IS_ERR(vol->lcnbmp_ino) || is_bad_inode(vol->lcnbmp_ino)) {
  		if (!IS_ERR(vol->lcnbmp_ino))
  			iput(vol->lcnbmp_ino);
  		goto bitmap_failed;
  	}

  	lockdep_set_class(&NTFS_I(vol->lcnbmp_ino)->runlist.lock,
  			   &lcnbmp_runlist_lock_key);
  	lockdep_set_class(&NTFS_I(vol->lcnbmp_ino)->mrec_lock,
  			   &lcnbmp_mrec_lock_key);

  	NInoSetSparseDisabled(NTFS_I(vol->lcnbmp_ino));

  	if ((vol->nr_clusters + 7) >> 3 > i_size_read(vol->lcnbmp_ino)) {

  		iput(vol->lcnbmp_ino);
  bitmap_failed:
  		ntfs_error(sb, "Failed to load $Bitmap.");
  		goto iput_attrdef_err_out;
  	}
  	/*
  	 * Get the volume inode and setup our cache of the volume flags and
  	 * version.
  	 */
  	vol->vol_ino = ntfs_iget(sb, FILE_Volume);
  	if (IS_ERR(vol->vol_ino) || is_bad_inode(vol->vol_ino)) {
  		if (!IS_ERR(vol->vol_ino))
  			iput(vol->vol_ino);
  volume_failed:
  		ntfs_error(sb, "Failed to load $Volume.");
  		goto iput_lcnbmp_err_out;
  	}
  	m = map_mft_record(NTFS_I(vol->vol_ino));
  	if (IS_ERR(m)) {
  iput_volume_failed:
  		iput(vol->vol_ino);
  		goto volume_failed;
  	}
  	if (!(ctx = ntfs_attr_get_search_ctx(NTFS_I(vol->vol_ino), m))) {
  		ntfs_error(sb, "Failed to get attribute search context.");
  		goto get_ctx_vol_failed;
  	}
  	if (ntfs_attr_lookup(AT_VOLUME_INFORMATION, NULL, 0, 0, 0, NULL, 0,
  			ctx) || ctx->attr->non_resident || ctx->attr->flags) {
  err_put_vol:
  		ntfs_attr_put_search_ctx(ctx);
  get_ctx_vol_failed:
  		unmap_mft_record(NTFS_I(vol->vol_ino));
  		goto iput_volume_failed;
  	}
  	vi = (VOLUME_INFORMATION*)((char*)ctx->attr +
  			le16_to_cpu(ctx->attr->data.resident.value_offset));
  	/* Some bounds checks. */
  	if ((u8*)vi < (u8*)ctx->attr || (u8*)vi +
  			le32_to_cpu(ctx->attr->data.resident.value_length) >
  			(u8*)ctx->attr + le32_to_cpu(ctx->attr->length))
  		goto err_put_vol;
  	/* Copy the volume flags and version to the ntfs_volume structure. */
  	vol->vol_flags = vi->flags;
  	vol->major_ver = vi->major_ver;
  	vol->minor_ver = vi->minor_ver;
  	ntfs_attr_put_search_ctx(ctx);
  	unmap_mft_record(NTFS_I(vol->vol_ino));

  	pr_info("volume version %i.%i.
  ", vol->major_ver,

  			vol->minor_ver);

  	if (vol->major_ver < 3 && NVolSparseEnabled(vol)) {
  		ntfs_warning(vol->sb, "Disabling sparse support due to NTFS "
  				"volume version %i.%i (need at least version "
  				"3.0).", vol->major_ver, vol->minor_ver);
  		NVolClearSparseEnabled(vol);
  	}

  #ifdef NTFS_RW
  	/* Make sure that no unsupported volume flags are set. */
  	if (vol->vol_flags & VOLUME_MUST_MOUNT_RO_MASK) {
  		static const char *es1a = "Volume is dirty";

  		static const char *es1b = "Volume has been modified by chkdsk";
  		static const char *es1c = "Volume has unsupported flags set";
  		static const char *es2a = ".  Run chkdsk and mount in Windows.";
  		static const char *es2b = ".  Mount in Windows.";
  		const char *es1, *es2;
  
  		es2 = es2a;
  		if (vol->vol_flags & VOLUME_IS_DIRTY)
  			es1 = es1a;
  		else if (vol->vol_flags & VOLUME_MODIFIED_BY_CHKDSK) {
  			es1 = es1b;
  			es2 = es2b;
  		} else {
  			es1 = es1c;
  			ntfs_warning(sb, "Unsupported volume flags 0x%x "
  					"encountered.",
  					(unsigned)le16_to_cpu(vol->vol_flags));
  		}

  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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_vol_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s", es1, es2);
  		/*
  		 * Do not set NVolErrors() because ntfs_remount() re-checks the
  		 * flags which we need to do in case any flags have changed.
  		 */
  	}
  	/*
  	 * Get the inode for the logfile, check it and determine if the volume
  	 * was shutdown cleanly.
  	 */

  	rp = NULL;
  	if (!load_and_check_logfile(vol, &rp) ||
  			!ntfs_is_logfile_clean(vol->logfile_ino, rp)) {

  		static const char *es1a = "Failed to load $LogFile";
  		static const char *es1b = "$LogFile is not clean";
  		static const char *es2 = ".  Mount in Windows.";
  		const char *es1;
  
  		es1 = !vol->logfile_ino ? es1a : es1b;
  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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);

  				if (vol->logfile_ino) {
  					BUG_ON(!rp);
  					ntfs_free(rp);
  				}

  				goto iput_logfile_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s", es1, es2);
  		/* This will prevent a read-write remount. */
  		NVolSetErrors(vol);
  	}

  	ntfs_free(rp);

  #endif /* NTFS_RW */
  	/* Get the root directory inode so we can do path lookups. */
  	vol->root_ino = ntfs_iget(sb, FILE_root);
  	if (IS_ERR(vol->root_ino) || is_bad_inode(vol->root_ino)) {
  		if (!IS_ERR(vol->root_ino))
  			iput(vol->root_ino);
  		ntfs_error(sb, "Failed to load root directory.");
  		goto iput_logfile_err_out;
  	}
  #ifdef NTFS_RW
  	/*
  	 * Check if Windows is suspended to disk on the target volume.  If it
  	 * is hibernated, we must not write *anything* to the disk so set
  	 * NVolErrors() without setting the dirty volume flag and mount
  	 * read-only.  This will prevent read-write remounting and it will also
  	 * prevent all writes.
  	 */
  	err = check_windows_hibernation_status(vol);
  	if (unlikely(err)) {
  		static const char *es1a = "Failed to determine if Windows is "
  				"hibernated";
  		static const char *es1b = "Windows is hibernated";
  		static const char *es2 = ".  Run chkdsk.";
  		const char *es1;
  
  		es1 = err < 0 ? es1a : es1b;
  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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_root_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s", es1, es2);
  		/* This will prevent a read-write remount. */
  		NVolSetErrors(vol);
  	}

  	/* If (still) a read-write mount, mark the volume dirty. */

  	if (!sb_rdonly(sb) && ntfs_set_volume_flags(vol, VOLUME_IS_DIRTY)) {

  		static const char *es1 = "Failed to set dirty bit in volume "
  				"information flags";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* 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_root_err_out;

  		}
  		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);

  		sb->s_flags |= SB_RDONLY;

  		/*
  		 * Do not set NVolErrors() because ntfs_remount() might manage
  		 * to set the dirty flag in which case all would be well.
  		 */
  	}
  #if 0
  	// TODO: Enable this code once we start modifying anything that is
  	//	 different between NTFS 1.2 and 3.x...
  	/*
  	 * If (still) a read-write mount, set the NT4 compatibility flag on
  	 * newer NTFS version volumes.
  	 */

  	if (!(sb->s_flags & SB_RDONLY) && (vol->major_ver > 1) &&

  			ntfs_set_volume_flags(vol, VOLUME_MOUNTED_ON_NT4)) {
  		static const char *es1 = "Failed to set NT4 compatibility flag";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* 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_root_err_out;

  		}
  		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);

  		sb->s_flags |= SB_RDONLY;

  		NVolSetErrors(vol);
  	}
  #endif
  	/* If (still) a read-write mount, empty the logfile. */

  	if (!sb_rdonly(sb) && !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_root_err_out;

  		}
  		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);

  		sb->s_flags |= SB_RDONLY;

  		NVolSetErrors(vol);
  	}
  #endif /* NTFS_RW */

  	/* If on NTFS versions before 3.0, we are done. */

  	if (unlikely(vol->major_ver < 3))

  		return true;

  	/* NTFS 3.0+ specific initialization. */
  	/* Get the security descriptors inode. */
  	vol->secure_ino = ntfs_iget(sb, FILE_Secure);
  	if (IS_ERR(vol->secure_ino) || is_bad_inode(vol->secure_ino)) {
  		if (!IS_ERR(vol->secure_ino))
  			iput(vol->secure_ino);
  		ntfs_error(sb, "Failed to load $Secure.");
  		goto iput_root_err_out;
  	}

  	// TODO: Initialize security.

  	/* Get the extended system files' directory inode. */
  	vol->extend_ino = ntfs_iget(sb, FILE_Extend);
  	if (IS_ERR(vol->extend_ino) || is_bad_inode(vol->extend_ino)) {
  		if (!IS_ERR(vol->extend_ino))
  			iput(vol->extend_ino);
  		ntfs_error(sb, "Failed to load $Extend.");
  		goto iput_sec_err_out;
  	}
  #ifdef NTFS_RW
  	/* Find the quota file, load it if present, and set it up. */
  	if (!load_and_init_quota(vol)) {
  		static const char *es1 = "Failed to load $Quota";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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_quota_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s", es1, es2);
  		/* This will prevent a read-write remount. */
  		NVolSetErrors(vol);
  	}
  	/* If (still) a read-write mount, mark the quotas out of date. */

  	if (!sb_rdonly(sb) && !ntfs_mark_quotas_out_of_date(vol)) {

  		static const char *es1 = "Failed to mark quotas out of date";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* 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_quota_err_out;
  		}
  		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);

  		sb->s_flags |= SB_RDONLY;

  		NVolSetErrors(vol);
  	}

  	/*
  	 * Find the transaction log file ($UsnJrnl), load it if present, check
  	 * it, and set it up.
  	 */
  	if (!load_and_init_usnjrnl(vol)) {
  		static const char *es1 = "Failed to load $UsnJrnl";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* If a read-write mount, convert it to a read-only mount. */

  		if (!sb_rdonly(sb)) {

  			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_usnjrnl_err_out;
  			}

  			sb->s_flags |= SB_RDONLY;

  			ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);
  		} else
  			ntfs_warning(sb, "%s.  Will not be able to remount "
  					"read-write%s", es1, es2);
  		/* This will prevent a read-write remount. */
  		NVolSetErrors(vol);
  	}
  	/* If (still) a read-write mount, stamp the transaction log. */

  	if (!sb_rdonly(sb) && !ntfs_stamp_usnjrnl(vol)) {

  		static const char *es1 = "Failed to stamp transaction log "
  				"($UsnJrnl)";
  		static const char *es2 = ".  Run chkdsk.";
  
  		/* 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_usnjrnl_err_out;
  		}
  		ntfs_error(sb, "%s.  Mounting read-only%s", es1, es2);

  		sb->s_flags |= SB_RDONLY;

  		NVolSetErrors(vol);
  	}

  #endif /* NTFS_RW */

  	return true;

  #ifdef NTFS_RW

  iput_usnjrnl_err_out:

  	iput(vol->usnjrnl_j_ino);
  	iput(vol->usnjrnl_max_ino);
  	iput(vol->usnjrnl_ino);

  iput_quota_err_out:

  	iput(vol->quota_q_ino);
  	iput(vol->quota_ino);

  	iput(vol->extend_ino);
  #endif /* NTFS_RW */
  iput_sec_err_out:
  	iput(vol->secure_ino);
  iput_root_err_out:
  	iput(vol->root_ino);
  iput_logfile_err_out:
  #ifdef NTFS_RW

  	iput(vol->logfile_ino);

  iput_vol_err_out:
  #endif /* NTFS_RW */
  	iput(vol->vol_ino);
  iput_lcnbmp_err_out:
  	iput(vol->lcnbmp_ino);
  iput_attrdef_err_out:
  	vol->attrdef_size = 0;
  	if (vol->attrdef) {
  		ntfs_free(vol->attrdef);
  		vol->attrdef = NULL;
  	}
  #ifdef NTFS_RW
  iput_upcase_err_out:
  #endif /* NTFS_RW */
  	vol->upcase_len = 0;

  	mutex_lock(&ntfs_lock);

  	if (vol->upcase == default_upcase) {
  		ntfs_nr_upcase_users--;
  		vol->upcase = NULL;
  	}

  	mutex_unlock(&ntfs_lock);

  	if (vol->upcase) {
  		ntfs_free(vol->upcase);
  		vol->upcase = NULL;
  	}
  iput_mftbmp_err_out:
  	iput(vol->mftbmp_ino);
  iput_mirr_err_out:
  #ifdef NTFS_RW

  	iput(vol->mftmirr_ino);

  #endif /* NTFS_RW */

  	return false;

  }
  
  /**
   * ntfs_put_super - called by the vfs to unmount a volume
   * @sb:		vfs superblock of volume to unmount
   *
   * ntfs_put_super() is called by the VFS (from fs/super.c::do_umount()) when
   * the volume is being unmounted (umount system call has been invoked) and it
   * releases all inodes and memory belonging to the NTFS specific part of the
   * super block.
   */
  static void ntfs_put_super(struct super_block *sb)
  {
  	ntfs_volume *vol = NTFS_SB(sb);
  
  	ntfs_debug("Entering.");

  #ifdef NTFS_RW
  	/*
  	 * Commit all inodes while they are still open in case some of them
  	 * cause others to be dirtied.
  	 */
  	ntfs_commit_inode(vol->vol_ino);
  
  	/* NTFS 3.0+ specific. */
  	if (vol->major_ver >= 3) {

  		if (vol->usnjrnl_j_ino)
  			ntfs_commit_inode(vol->usnjrnl_j_ino);
  		if (vol->usnjrnl_max_ino)
  			ntfs_commit_inode(vol->usnjrnl_max_ino);
  		if (vol->usnjrnl_ino)
  			ntfs_commit_inode(vol->usnjrnl_ino);

  		if (vol->quota_q_ino)
  			ntfs_commit_inode(vol->quota_q_ino);
  		if (vol->quota_ino)
  			ntfs_commit_inode(vol->quota_ino);
  		if (vol->extend_ino)
  			ntfs_commit_inode(vol->extend_ino);
  		if (vol->secure_ino)
  			ntfs_commit_inode(vol->secure_ino);
  	}
  
  	ntfs_commit_inode(vol->root_ino);
  
  	down_write(&vol->lcnbmp_lock);
  	ntfs_commit_inode(vol->lcnbmp_ino);
  	up_write(&vol->lcnbmp_lock);
  
  	down_write(&vol->mftbmp_lock);
  	ntfs_commit_inode(vol->mftbmp_ino);
  	up_write(&vol->mftbmp_lock);
  
  	if (vol->logfile_ino)
  		ntfs_commit_inode(vol->logfile_ino);
  
  	if (vol->mftmirr_ino)
  		ntfs_commit_inode(vol->mftmirr_ino);
  	ntfs_commit_inode(vol->mft_ino);
  
  	/*

  	 * If a read-write mount and no volume errors have occurred, mark the

  	 * volume clean.  Also, re-commit all affected inodes.
  	 */

  	if (!sb_rdonly(sb)) {

  		if (!NVolErrors(vol)) {
  			if (ntfs_clear_volume_flags(vol, VOLUME_IS_DIRTY))
  				ntfs_warning(sb, "Failed to clear dirty bit "
  						"in volume information "
  						"flags.  Run chkdsk.");
  			ntfs_commit_inode(vol->vol_ino);
  			ntfs_commit_inode(vol->root_ino);
  			if (vol->mftmirr_ino)
  				ntfs_commit_inode(vol->mftmirr_ino);
  			ntfs_commit_inode(vol->mft_ino);
  		} else {
  			ntfs_warning(sb, "Volume has errors.  Leaving volume "
  					"marked dirty.  Run chkdsk.");
  		}
  	}
  #endif /* NTFS_RW */
  
  	iput(vol->vol_ino);
  	vol->vol_ino = NULL;
  
  	/* NTFS 3.0+ specific clean up. */
  	if (vol->major_ver >= 3) {
  #ifdef NTFS_RW

  		if (vol->usnjrnl_j_ino) {
  			iput(vol->usnjrnl_j_ino);
  			vol->usnjrnl_j_ino = NULL;
  		}
  		if (vol->usnjrnl_max_ino) {
  			iput(vol->usnjrnl_max_ino);
  			vol->usnjrnl_max_ino = NULL;
  		}
  		if (vol->usnjrnl_ino) {
  			iput(vol->usnjrnl_ino);
  			vol->usnjrnl_ino = NULL;
  		}

  		if (vol->quota_q_ino) {
  			iput(vol->quota_q_ino);
  			vol->quota_q_ino = NULL;
  		}
  		if (vol->quota_ino) {
  			iput(vol->quota_ino);
  			vol->quota_ino = NULL;
  		}
  #endif /* NTFS_RW */
  		if (vol->extend_ino) {
  			iput(vol->extend_ino);
  			vol->extend_ino = NULL;
  		}
  		if (vol->secure_ino) {
  			iput(vol->secure_ino);
  			vol->secure_ino = NULL;
  		}
  	}
  
  	iput(vol->root_ino);
  	vol->root_ino = NULL;
  
  	down_write(&vol->lcnbmp_lock);
  	iput(vol->lcnbmp_ino);
  	vol->lcnbmp_ino = NULL;
  	up_write(&vol->lcnbmp_lock);
  
  	down_write(&vol->mftbmp_lock);
  	iput(vol->mftbmp_ino);
  	vol->mftbmp_ino = NULL;
  	up_write(&vol->mftbmp_lock);
  
  #ifdef NTFS_RW
  	if (vol->logfile_ino) {
  		iput(vol->logfile_ino);
  		vol->logfile_ino = NULL;
  	}
  	if (vol->mftmirr_ino) {
  		/* Re-commit the mft mirror and mft just in case. */
  		ntfs_commit_inode(vol->mftmirr_ino);
  		ntfs_commit_inode(vol->mft_ino);
  		iput(vol->mftmirr_ino);
  		vol->mftmirr_ino = NULL;
  	}
  	/*

  	 * We should have no dirty inodes left, due to
  	 * mft.c::ntfs_mft_writepage() cleaning all the dirty pages as
  	 * the underlying mft records are written out and cleaned.

  	 */
  	ntfs_commit_inode(vol->mft_ino);
  	write_inode_now(vol->mft_ino, 1);

  #endif /* NTFS_RW */
  
  	iput(vol->mft_ino);
  	vol->mft_ino = NULL;
  
  	/* Throw away the table of attribute definitions. */
  	vol->attrdef_size = 0;
  	if (vol->attrdef) {
  		ntfs_free(vol->attrdef);
  		vol->attrdef = NULL;
  	}
  	vol->upcase_len = 0;
  	/*
  	 * Destroy the global default upcase table if necessary.  Also decrease
  	 * the number of upcase users if we are a user.
  	 */

  	mutex_lock(&ntfs_lock);

  	if (vol->upcase == default_upcase) {
  		ntfs_nr_upcase_users--;
  		vol->upcase = NULL;
  	}
  	if (!ntfs_nr_upcase_users && default_upcase) {
  		ntfs_free(default_upcase);
  		default_upcase = NULL;
  	}
  	if (vol->cluster_size <= 4096 && !--ntfs_nr_compression_users)
  		free_compression_buffers();

  	mutex_unlock(&ntfs_lock);

  	if (vol->upcase) {
  		ntfs_free(vol->upcase);
  		vol->upcase = NULL;
  	}

  
  	unload_nls(vol->nls_map);

  	sb->s_fs_info = NULL;
  	kfree(vol);

  }
  
  /**
   * get_nr_free_clusters - return the number of free clusters on a volume
   * @vol:	ntfs volume for which to obtain free cluster count
   *
   * Calculate the number of free clusters on the mounted NTFS volume @vol. We
   * actually calculate the number of clusters in use instead because this
   * allows us to not care about partial pages as these will be just zero filled
   * and hence not be counted as allocated clusters.
   *
   * The only particularity is that clusters beyond the end of the logical ntfs
   * volume will be marked as allocated to prevent errors which means we have to
   * discount those at the end. This is important as the cluster bitmap always
   * has a size in multiples of 8 bytes, i.e. up to 63 clusters could be outside
   * the logical volume and marked in use when they are not as they do not exist.
   *
   * If any pages cannot be read we assume all clusters in the erroring pages are
   * in use. This means we return an underestimate on errors which is better than
   * an overestimate.
   */
  static s64 get_nr_free_clusters(ntfs_volume *vol)
  {
  	s64 nr_free = vol->nr_clusters;

  	struct address_space *mapping = vol->lcnbmp_ino->i_mapping;

  	struct page *page;

  	pgoff_t index, max_index;

  
  	ntfs_debug("Entering.");
  	/* Serialize accesses to the cluster bitmap. */
  	down_read(&vol->lcnbmp_lock);
  	/*
  	 * Convert the number of bits into bytes rounded up, then convert into

  	 * multiples of PAGE_SIZE, rounding up so that if we have one

  	 * full and one partial page max_index = 2.
  	 */

  	max_index = (((vol->nr_clusters + 7) >> 3) + PAGE_SIZE - 1) >>
  			PAGE_SHIFT;

  	/* Use multiples of 4 bytes, thus max_size is PAGE_SIZE / 4. */

  	ntfs_debug("Reading $Bitmap, max_index = 0x%lx, max_size = 0x%lx.",

  			max_index, PAGE_SIZE / 4);

  	for (index = 0; index < max_index; index++) {

  		unsigned long *kaddr;

  		/*
  		 * Read the page from page cache, getting it from backing store
  		 * if necessary, and increment the use count.
  		 */

  		page = read_mapping_page(mapping, index, NULL);

  		/* Ignore pages which errored synchronously. */
  		if (IS_ERR(page)) {

  			ntfs_debug("read_mapping_page() error. Skipping "

  					"page (index 0x%lx).", index);

  			nr_free -= PAGE_SIZE * 8;

  			continue;
  		}

  		kaddr = kmap_atomic(page);

  		/*

  		 * Subtract the number of set bits. If this

  		 * is the last page and it is partial we don't really care as
  		 * it just means we do a little extra work but it won't affect
  		 * the result as all out of range bytes are set to zero by
  		 * ntfs_readpage().
  		 */

  		nr_free -= bitmap_weight(kaddr,

  					PAGE_SIZE * BITS_PER_BYTE);

  		kunmap_atomic(kaddr);

  		put_page(page);

  	}
  	ntfs_debug("Finished reading $Bitmap, last index = 0x%lx.", index - 1);
  	/*
  	 * Fixup for eventual bits outside logical ntfs volume (see function
  	 * description above).
  	 */
  	if (vol->nr_clusters & 63)
  		nr_free += 64 - (vol->nr_clusters & 63);
  	up_read(&vol->lcnbmp_lock);

  	/* If errors occurred we may well have gone below zero, fix this. */

  	if (nr_free < 0)
  		nr_free = 0;
  	ntfs_debug("Exiting.");
  	return nr_free;
  }
  
  /**
   * __get_nr_free_mft_records - return the number of free inodes on a volume
   * @vol:	ntfs volume for which to obtain free inode count

   * @nr_free:	number of mft records in filesystem

   * @max_index:	maximum number of pages containing set bits

   *
   * Calculate the number of free mft records (inodes) on the mounted NTFS
   * volume @vol. We actually calculate the number of mft records in use instead
   * because this allows us to not care about partial pages as these will be just
   * zero filled and hence not be counted as allocated mft record.
   *
   * If any pages cannot be read we assume all mft records in the erroring pages
   * are in use. This means we return an underestimate on errors which is better
   * than an overestimate.
   *
   * NOTE: Caller must hold mftbmp_lock rw_semaphore for reading or writing.
   */

  static unsigned long __get_nr_free_mft_records(ntfs_volume *vol,
  		s64 nr_free, const pgoff_t max_index)

  {

  	struct address_space *mapping = vol->mftbmp_ino->i_mapping;

  	struct page *page;

  	pgoff_t index;

  
  	ntfs_debug("Entering.");

  	/* Use multiples of 4 bytes, thus max_size is PAGE_SIZE / 4. */

  	ntfs_debug("Reading $MFT/$BITMAP, max_index = 0x%lx, max_size = "

  			"0x%lx.", max_index, PAGE_SIZE / 4);

  	for (index = 0; index < max_index; index++) {

  		unsigned long *kaddr;

  		/*
  		 * Read the page from page cache, getting it from backing store
  		 * if necessary, and increment the use count.
  		 */

  		page = read_mapping_page(mapping, index, NULL);

  		/* Ignore pages which errored synchronously. */
  		if (IS_ERR(page)) {

  			ntfs_debug("read_mapping_page() error. Skipping "

  					"page (index 0x%lx).", index);

  			nr_free -= PAGE_SIZE * 8;

  			continue;
  		}

  		kaddr = kmap_atomic(page);

  		/*

  		 * Subtract the number of set bits. If this

  		 * is the last page and it is partial we don't really care as
  		 * it just means we do a little extra work but it won't affect
  		 * the result as all out of range bytes are set to zero by
  		 * ntfs_readpage().
  		 */

  		nr_free -= bitmap_weight(kaddr,

  					PAGE_SIZE * BITS_PER_BYTE);

  		kunmap_atomic(kaddr);

  		put_page(page);

  	}
  	ntfs_debug("Finished reading $MFT/$BITMAP, last index = 0x%lx.",
  			index - 1);

  	/* If errors occurred we may well have gone below zero, fix this. */

  	if (nr_free < 0)
  		nr_free = 0;
  	ntfs_debug("Exiting.");
  	return nr_free;
  }
  
  /**
   * ntfs_statfs - return information about mounted NTFS volume

   * @dentry:	dentry from mounted volume

   * @sfs:	statfs structure in which to return the information
   *

   * Return information about the mounted NTFS volume @dentry in the statfs structure

   * pointed to by @sfs (this is initialized with zeros before ntfs_statfs is
   * called). We interpret the values to be correct of the moment in time at
   * which we are called. Most values are variable otherwise and this isn't just
   * the free values but the totals as well. For example we can increase the
   * total number of file nodes if we run out and we can keep doing this until
   * there is no more space on the volume left at all.
   *
   * Called from vfs_statfs which is used to handle the statfs, fstatfs, and
   * ustat system calls.
   *
   * Return 0 on success or -errno on error.
   */

  static int ntfs_statfs(struct dentry *dentry, struct kstatfs *sfs)

  {

  	struct super_block *sb = dentry->d_sb;

  	s64 size;

  	ntfs_volume *vol = NTFS_SB(sb);
  	ntfs_inode *mft_ni = NTFS_I(vol->mft_ino);
  	pgoff_t max_index;
  	unsigned long flags;

  
  	ntfs_debug("Entering.");
  	/* Type of filesystem. */
  	sfs->f_type   = NTFS_SB_MAGIC;
  	/* Optimal transfer block size. */

  	sfs->f_bsize  = PAGE_SIZE;

  	/*

  	 * Total data blocks in filesystem in units of f_bsize and since

  	 * inodes are also stored in data blocs ($MFT is a file) this is just
  	 * the total clusters.
  	 */
  	sfs->f_blocks = vol->nr_clusters << vol->cluster_size_bits >>

  				PAGE_SHIFT;

  	/* Free data blocks in filesystem in units of f_bsize. */

  	size	      = get_nr_free_clusters(vol) << vol->cluster_size_bits >>

  				PAGE_SHIFT;

  	if (size < 0LL)
  		size = 0LL;
  	/* Free blocks avail to non-superuser, same as above on NTFS. */
  	sfs->f_bavail = sfs->f_bfree = size;
  	/* Serialize accesses to the inode bitmap. */
  	down_read(&vol->mftbmp_lock);

  	read_lock_irqsave(&mft_ni->size_lock, flags);
  	size = i_size_read(vol->mft_ino) >> vol->mft_record_size_bits;
  	/*
  	 * Convert the maximum number of set bits into bytes rounded up, then

  	 * convert into multiples of PAGE_SIZE, rounding up so that if we

  	 * have one full and one partial page max_index = 2.
  	 */
  	max_index = ((((mft_ni->initialized_size >> vol->mft_record_size_bits)

  			+ 7) >> 3) + PAGE_SIZE - 1) >> PAGE_SHIFT;

  	read_unlock_irqrestore(&mft_ni->size_lock, flags);

  	/* Number of inodes in filesystem (at this point in time). */

  	sfs->f_files = size;

  	/* Free inodes in fs (based on current total count). */

  	sfs->f_ffree = __get_nr_free_mft_records(vol, size, max_index);

  	up_read(&vol->mftbmp_lock);
  	/*
  	 * File system id. This is extremely *nix flavour dependent and even
  	 * within Linux itself all fs do their own thing. I interpret this to
  	 * mean a unique id associated with the mounted fs and not the id

  	 * associated with the filesystem driver, the latter is already given
  	 * by the filesystem type in sfs->f_type. Thus we use the 64-bit

  	 * volume serial number splitting it into two 32-bit parts. We enter
  	 * the least significant 32-bits in f_fsid[0] and the most significant
  	 * 32-bits in f_fsid[1].
  	 */

  	sfs->f_fsid = u64_to_fsid(vol->serial_no);

  	/* Maximum length of filenames. */
  	sfs->f_namelen	   = NTFS_MAX_NAME_LEN;
  	return 0;
  }

  #ifdef NTFS_RW
  static int ntfs_write_inode(struct inode *vi, struct writeback_control *wbc)
  {
  	return __ntfs_write_inode(vi, wbc->sync_mode == WB_SYNC_ALL);
  }
  #endif

  /**
   * The complete super operations.
   */

  static const struct super_operations ntfs_sops = {

  	.alloc_inode	= ntfs_alloc_big_inode,	  /* VFS: Allocate new inode. */

  	.free_inode	= ntfs_free_big_inode, /* VFS: Deallocate inode. */

  #ifdef NTFS_RW

  	.write_inode	= ntfs_write_inode,	/* VFS: Write dirty inode to
  						   disk. */

  #endif /* NTFS_RW */
  	.put_super	= ntfs_put_super,	/* Syscall: umount. */
  	.statfs		= ntfs_statfs,		/* Syscall: statfs */
  	.remount_fs	= ntfs_remount,		/* Syscall: mount -o remount. */

  	.evict_inode	= ntfs_evict_big_inode,	/* VFS: Called when an inode is

  						   removed from memory. */

  	.show_options	= ntfs_show_options,	/* Show mount options in
  						   proc. */
  };

  /**

   * ntfs_fill_super - mount an ntfs filesystem
   * @sb:		super block of ntfs filesystem to mount

   * @opt:	string containing the mount options
   * @silent:	silence error output
   *
   * ntfs_fill_super() is called by the VFS to mount the device described by @sb

   * with the mount otions in @data with the NTFS filesystem.

   *
   * If @silent is true, remain silent even if errors are detected. This is used

   * during bootup, when the kernel tries to mount the root filesystem with all
   * registered filesystems one after the other until one succeeds. This implies
   * that all filesystems except the correct one will quite correctly and

   * expectedly return an error, but nobody wants to see error messages when in
   * fact this is what is supposed to happen.
   *
   * NOTE: @sb->s_flags contains the mount options flags.
   */
  static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
  {
  	ntfs_volume *vol;
  	struct buffer_head *bh;
  	struct inode *tmp_ino;

  	int blocksize, result;

  	/*
  	 * We do a pretty difficult piece of bootstrap by reading the
  	 * MFT (and other metadata) from disk into memory. We'll only
  	 * release this metadata during umount, so the locking patterns
  	 * observed during bootstrap do not count. So turn off the
  	 * observation of locking patterns (strictly for this context
  	 * only) while mounting NTFS. [The validator is still active
  	 * otherwise, even for this context: it will for example record
  	 * lock class registrations.]
  	 */
  	lockdep_off();

  	ntfs_debug("Entering.");
  #ifndef NTFS_RW

  	sb->s_flags |= SB_RDONLY;

  #endif /* ! NTFS_RW */
  	/* Allocate a new ntfs_volume and place it in sb->s_fs_info. */
  	sb->s_fs_info = kmalloc(sizeof(ntfs_volume), GFP_NOFS);
  	vol = NTFS_SB(sb);
  	if (!vol) {
  		if (!silent)
  			ntfs_error(sb, "Allocation of NTFS volume structure "
  					"failed. Aborting mount...");

  		lockdep_on();

  		return -ENOMEM;
  	}
  	/* Initialize ntfs_volume structure. */

  	*vol = (ntfs_volume) {
  		.sb = sb,
  		/*
  		 * Default is group and other don't have any access to files or
  		 * directories while owner has full access. Further, files by
  		 * default are not executable but directories are of course
  		 * browseable.
  		 */
  		.fmask = 0177,
  		.dmask = 0077,
  	};

  	init_rwsem(&vol->mftbmp_lock);

  	init_rwsem(&vol->lcnbmp_lock);

  	/* By default, enable sparse support. */
  	NVolSetSparseEnabled(vol);

  	/* Important to get the mount options dealt with now. */
  	if (!parse_options(vol, (char*)opt))
  		goto err_out_now;

  	/* We support sector sizes up to the PAGE_SIZE. */

  	if (bdev_logical_block_size(sb->s_bdev) > PAGE_SIZE) {

  		if (!silent)
  			ntfs_error(sb, "Device has unsupported sector size "
  					"(%i).  The maximum supported sector "
  					"size on this architecture is %lu "
  					"bytes.",

  					bdev_logical_block_size(sb->s_bdev),

  					PAGE_SIZE);

  		goto err_out_now;
  	}

  	/*

  	 * Setup the device access block size to NTFS_BLOCK_SIZE or the hard
  	 * sector size, whichever is bigger.

  	 */

  	blocksize = sb_min_blocksize(sb, NTFS_BLOCK_SIZE);
  	if (blocksize < NTFS_BLOCK_SIZE) {

  		if (!silent)

  			ntfs_error(sb, "Unable to set device block size.");

  		goto err_out_now;
  	}

  	BUG_ON(blocksize != sb->s_blocksize);
  	ntfs_debug("Set device block size to %i bytes (block size bits %i).",
  			blocksize, sb->s_blocksize_bits);
  	/* Determine the size of the device in units of block_size bytes. */
  	if (!i_size_read(sb->s_bdev->bd_inode)) {

  		if (!silent)

  			ntfs_error(sb, "Unable to determine device size.");

  		goto err_out_now;
  	}

  	vol->nr_blocks = i_size_read(sb->s_bdev->bd_inode) >>

  			sb->s_blocksize_bits;

  	/* Read the boot sector and return unlocked buffer head to it. */
  	if (!(bh = read_ntfs_boot_sector(sb, silent))) {
  		if (!silent)
  			ntfs_error(sb, "Not an NTFS volume.");
  		goto err_out_now;
  	}

  	/*

  	 * Extract the data from the boot sector and setup the ntfs volume

  	 * using it.
  	 */
  	result = parse_ntfs_boot_sector(vol, (NTFS_BOOT_SECTOR*)bh->b_data);

  	brelse(bh);

  	if (!result) {
  		if (!silent)
  			ntfs_error(sb, "Unsupported NTFS filesystem.");
  		goto err_out_now;
  	}

  	/*

  	 * If the boot sector indicates a sector size bigger than the current
  	 * device block size, switch the device block size to the sector size.
  	 * TODO: It may be possible to support this case even when the set
  	 * below fails, we would just be breaking up the i/o for each sector
  	 * into multiple blocks for i/o purposes but otherwise it should just
  	 * work.  However it is safer to leave disabled until someone hits this
  	 * error message and then we can get them to try it without the setting
  	 * so we know for sure that it works.

  	 */

  	if (vol->sector_size > blocksize) {
  		blocksize = sb_set_blocksize(sb, vol->sector_size);
  		if (blocksize != vol->sector_size) {
  			if (!silent)
  				ntfs_error(sb, "Unable to set device block "
  						"size to sector size (%i).",
  						vol->sector_size);
  			goto err_out_now;
  		}
  		BUG_ON(blocksize != sb->s_blocksize);
  		vol->nr_blocks = i_size_read(sb->s_bdev->bd_inode) >>
  				sb->s_blocksize_bits;
  		ntfs_debug("Changed device block size to %i bytes (block size "
  				"bits %i) to match volume sector size.",
  				blocksize, sb->s_blocksize_bits);
  	}
  	/* Initialize the cluster and mft allocators. */
  	ntfs_setup_allocators(vol);