super.c

linux 内核源代码

 * 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;
	ntfs_inode *ni;
	struct page *page;
	u32 *kaddr, *kend;
	ntfs_name *name = NULL;
	int ret = 1;
	static const ntfschar hiberfil[13] = { const_cpu_to_le16('h'),
			const_cpu_to_le16('i'), const_cpu_to_le16('b'),
			const_cpu_to_le16('e'), const_cpu_to_le16('r'),
			const_cpu_to_le16('f'), const_cpu_to_le16('i'),
			const_cpu_to_le16('l'), const_cpu_to_le16('.'),
			const_cpu_to_le16('s'), const_cpu_to_le16('y'),
			const_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.
	 */
	mutex_lock(&vol->root_ino->i_mutex);
	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->root_ino), hiberfil, 12,
			&name);
	mutex_unlock(&vol->root_ino->i_mutex);
	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 occured. */
		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;
	}
	ni = NTFS_I(vi);
	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 == const_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 $Quota is not present, we
 * leave vol->quota_ino as NULL and return success.
 */
static bool load_and_init_quota(ntfs_volume *vol)
{
	MFT_REF mref;
	struct inode *tmp_ino;
	ntfs_name *name = NULL;
	static const ntfschar Quota[7] = { const_cpu_to_le16('$'),
			const_cpu_to_le16('Q'), const_cpu_to_le16('u'),
			const_cpu_to_le16('o'), const_cpu_to_le16('t'),
			const_cpu_to_le16('a'), 0 };
	static ntfschar Q[3] = { const_cpu_to_le16('$'),
			const_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 $Extend.
	 */
	mutex_lock(&vol->extend_ino->i_mutex);
	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->extend_ino), Quota, 6,
			&name);
	mutex_unlock(&vol->extend_ino->i_mutex);
	if (IS_ERR_MREF(mref)) {
		/*
		 * If the file does not exist, quotas are disabled and have
		 * never been enabled on this volume, just return success.
		 */
		if (MREF_ERR(mref) == -ENOENT) {
			ntfs_debug("$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 occured. */
		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] = { const_cpu_to_le16('$'),
			const_cpu_to_le16('U'), const_cpu_to_le16('s'),
			const_cpu_to_le16('n'), const_cpu_to_le16('J'),
			const_cpu_to_le16('r'), const_cpu_to_le16('n'),
			const_cpu_to_le16('l'), 0 };
	static ntfschar Max[5] = { const_cpu_to_le16('$'),
			const_cpu_to_le16('M'), const_cpu_to_le16('a'),
			const_cpu_to_le16('x'), 0 };
	static ntfschar J[3] = { const_cpu_to_le16('$'),
			const_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 $Extend.
	 */
	mutex_lock(&vol->extend_ino->i_mutex);
	mref = ntfs_lookup_inode_by_name(NTFS_I(vol->extend_ino), UsnJrnl, 8,
			&name);
	mutex_unlock(&vol->extend_ino->i_mutex);
	if (IS_ERR_MREF(mref)) {
		/*
		 * If the file does not exist, transaction logging is disabled,
		 * just return success.
		 */
		if (MREF_ERR(mref) == -ENOENT) {
			ntfs_debug("$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 occured. */
		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 (unlikely(IS_ERR(tmp_ino) || 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_CACHE_SHIFT;
	size = PAGE_CACHE_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_CACHE_SHIFT),
				page_address(page), size);
		ntfs_unmap_page(page);
	};
	if (size == PAGE_CACHE_SIZE) {
		size = i_size & ~PAGE_CACHE_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: