mft.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

			size = ll << 3;
			bit = data_pos & 7;
			data_pos &= ~7ull;
			ntfs_log_debug("Before inner for loop: size 0x%x, "
					"data_pos 0x%llx, bit 0x%llx, "
					"*byte 0x%hhx, b %u.\n", size,
					(long long)data_pos, (long long)bit,
					byte ? *byte : -1, b);
			for (; bit < size && data_pos + bit < pass_end;
					bit &= ~7ull, bit += 8) {
				byte = buf + (bit >> 3);
				if (*byte == 0xff)
					continue;
				/* Note: ffz() result must be zero based. */
				b = ntfs_ffz((unsigned long)*byte);
				if (b < 8 && b >= (bit & 7)) {
					free(buf);
					return data_pos + (bit & ~7ull) + b;
				}
			}
			ntfs_log_debug("After inner for loop: size 0x%x, "
					"data_pos 0x%llx, bit 0x%llx, "
					"*byte 0x%hhx, b %u.\n", size,
					(long long)data_pos, (long long)bit,
					byte ? *byte : -1, b);
			data_pos += size;
			/*
			 * If the end of the pass has not been reached yet,
			 * continue searching the mft bitmap for a zero bit.
			 */
			if (data_pos < pass_end)
				continue;
		}
		/* Do the next pass. */
		pass++;
		if (pass == 2) {
			/*
			 * Starting the second pass, in which we scan the first
			 * part of the zone which we omitted earlier.
			 */
			pass_end = pass_start;
			data_pos = pass_start = 24;
			ntfs_log_debug("pass %i, pass_start 0x%llx, pass_end "
					"0x%llx.\n", pass, (long long)pass_start,
					(long long)pass_end);
			if (data_pos >= pass_end)
				break;
		}
	}
	/* No free mft records in currently initialized mft bitmap. */
	free(buf);
	errno = ENOSPC;
	return -1;
}

/**
 * ntfs_mft_bitmap_extend_allocation - extend mft bitmap attribute by a cluster
 * @vol:	volume on which to extend the mft bitmap attribute
 *
 * Extend the mft bitmap attribute on the ntfs volume @vol by one cluster.
 *
 * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
 * data_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_bitmap_extend_allocation(ntfs_volume *vol)
{
	LCN lcn;
	s64 ll = 0; /* silence compiler warning */
	ntfs_attr *mftbmp_na, *lcnbmp_na;
	runlist_element *rl, *rl2 = NULL; /* silence compiler warning */
	ntfs_attr_search_ctx *ctx;
	MFT_RECORD *m = NULL; /* silence compiler warning */
	ATTR_RECORD *a = NULL; /* silence compiler warning */
	int ret, mp_size;
	u32 old_alen = 0; /* silence compiler warning */
	u8 b, tb;
	struct {
		u8 added_cluster:1;
		u8 added_run:1;
		u8 mp_rebuilt:1;
	} status = { 0, 0, 0 };

	mftbmp_na = vol->mftbmp_na;
	lcnbmp_na = vol->lcnbmp_na;
	/*
	 * Determine the last lcn of the mft bitmap.  The allocated size of the
	 * mft bitmap cannot be zero so we are ok to do this.
	 */
	rl = ntfs_attr_find_vcn(mftbmp_na, (mftbmp_na->allocated_size - 1) >>
			vol->cluster_size_bits);
	if (!rl || !rl->length || rl->lcn < 0) {
		ntfs_log_error("Failed to determine last allocated "
				"cluster of mft bitmap attribute.\n");
		if (rl)
			errno = EIO;
		return -1;
	}
	lcn = rl->lcn + rl->length;
	/*
	 * Attempt to get the cluster following the last allocated cluster by
	 * hand as it may be in the MFT zone so the allocator would not give it
	 * to us.
	 */
	ret = (int)ntfs_attr_pread(lcnbmp_na, lcn >> 3, 1, &b);
	if (ret < 0) {
		ntfs_log_error("Failed to read from lcn bitmap.\n");
		return -1;
	}
	ntfs_log_debug("Read %i byte%s.\n", ret, ret == 1 ? "" : "s");
	tb = 1 << (lcn & 7ull);
	if (ret == 1 && b != 0xff && !(b & tb)) {
		/* Next cluster is free, allocate it. */
		b |= tb;
		ret = (int)ntfs_attr_pwrite(lcnbmp_na, lcn >> 3, 1, &b);
		if (ret < 1) {
			ntfs_log_error("Failed to write to lcn "
					"bitmap.\n");
			if (!ret)
				errno = EIO;
			return -1;
		}
		/* Update the mft bitmap runlist. */
		rl->length++;
		rl[1].vcn++;
		status.added_cluster = 1;
		ntfs_log_debug("Appending one cluster to mft bitmap.\n");
	} else {
		/* Allocate a cluster from the DATA_ZONE. */
		rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE);
		if (!rl2) {
			ntfs_log_error("Failed to allocate a cluster for "
					"the mft bitmap.\n");
			return -1;
		}
		rl = ntfs_runlists_merge(mftbmp_na->rl, rl2);
		if (!rl) {
			ret = errno;
			ntfs_log_error("Failed to merge runlists for mft "
					"bitmap.\n");
			if (ntfs_cluster_free_from_rl(vol, rl2))
				ntfs_log_error("Failed to deallocate "
						"cluster.%s\n", es);
			free(rl2);
			errno = ret;
			return -1;
		}
		mftbmp_na->rl = rl;
		status.added_run = 1;
		ntfs_log_debug("Adding one run to mft bitmap.\n");
		/* Find the last run in the new runlist. */
		for (; rl[1].length; rl++)
			;
	}
	/*
	 * Update the attribute record as well.  Note: @rl is the last
	 * (non-terminator) runlist element of mft bitmap.
	 */
	ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
	if (!ctx) {
		ntfs_log_error("Failed to get search context.\n");
		goto undo_alloc;
	}
	if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name,
			mftbmp_na->name_len, 0, rl[1].vcn, NULL, 0, ctx)) {
		ntfs_log_error("Failed to find last attribute extent of "
				"mft bitmap attribute.\n");
		goto undo_alloc;
	}
	m = ctx->mrec;
	a = ctx->attr;
	ll = sle64_to_cpu(a->lowest_vcn);
	rl2 = ntfs_attr_find_vcn(mftbmp_na, ll);
	if (!rl2 || !rl2->length) {
		ntfs_log_error("Failed to determine previous last "
				"allocated cluster of mft bitmap attribute.\n");
		if (rl2)
			errno = EIO;
		goto undo_alloc;
	}
	/* Get the size for the new mapping pairs array for this extent. */
	mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll);
	if (mp_size <= 0) {
		ntfs_log_error("Get size for mapping pairs failed for "
				"mft bitmap attribute extent.\n");
		goto undo_alloc;
	}
	/* Expand the attribute record if necessary. */
	old_alen = le32_to_cpu(a->length);
	if (ntfs_attr_record_resize(m, a, mp_size +
			le16_to_cpu(a->mapping_pairs_offset))) {
		if (errno != ENOSPC) {
			ntfs_log_error("Failed to resize attribute "
					"record for mft bitmap attribute.\n");
			goto undo_alloc;
		}
		// TODO: Deal with this by moving this extent to a new mft
		// record or by starting a new extent in a new mft record.
		ntfs_log_error("Not enough space in this mft record to "
				"accommodate extended mft bitmap attribute "
				"extent.  Cannot handle this yet.\n");
		errno = EOPNOTSUPP;
		goto undo_alloc;
	}
	status.mp_rebuilt = 1;
	/* Generate the mapping pairs array directly into the attr record. */
	if (ntfs_mapping_pairs_build(vol, (u8*)a +
			le16_to_cpu(a->mapping_pairs_offset), mp_size, rl2, ll,
			NULL)) {
		ntfs_log_error("Failed to build mapping pairs array for "
				"mft bitmap attribute.\n");
		errno = EIO;
		goto undo_alloc;
	}
	/* Update the highest_vcn. */
	a->highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
	/*
	 * We now have extended the mft bitmap allocated_size by one cluster.
	 * Reflect this in the ntfs_attr structure and the attribute record.
	 */
	if (a->lowest_vcn) {
		/*
		 * We are not in the first attribute extent, switch to it, but
		 * first ensure the changes will make it to disk later.
		 */
		ntfs_inode_mark_dirty(ctx->ntfs_ino);
		ntfs_attr_reinit_search_ctx(ctx);
		if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name,
				mftbmp_na->name_len, 0, 0, NULL, 0, ctx)) {
			ntfs_log_error("Failed to find first attribute "
					"extent of mft bitmap attribute.\n");
			goto restore_undo_alloc;
		}
		a = ctx->attr;
	}
	mftbmp_na->allocated_size += vol->cluster_size;
	a->allocated_size = cpu_to_sle64(mftbmp_na->allocated_size);
	/* Ensure the changes make it to disk. */
	ntfs_inode_mark_dirty(ctx->ntfs_ino);
	ntfs_attr_put_search_ctx(ctx);
	return 0;
restore_undo_alloc:
	ret = errno;
	ntfs_attr_reinit_search_ctx(ctx);
	if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name,
			mftbmp_na->name_len, 0, rl[1].vcn, NULL, 0, ctx)) {
		ntfs_log_error("Failed to find last attribute extent of "
				"mft bitmap attribute.%s\n", es);
		ntfs_attr_put_search_ctx(ctx);
		mftbmp_na->allocated_size += vol->cluster_size;
		/*
		 * The only thing that is now wrong is ->allocated_size of the
		 * base attribute extent which chkdsk should be able to fix.
		 */
		errno = ret;
		return -1;
	}
	m = ctx->mrec;
	a = ctx->attr;
	a->highest_vcn = cpu_to_sle64(rl[1].vcn - 2);
	errno = ret;
undo_alloc:
	ret = errno;
	if (status.added_cluster) {
		/* Truncate the last run in the runlist by one cluster. */
		rl->length--;
		rl[1].vcn--;
	} else if (status.added_run) {
		lcn = rl->lcn;
		/* Remove the last run from the runlist. */
		rl->lcn = rl[1].lcn;
		rl->length = 0;
	}
	/* Deallocate the cluster. */
	if (ntfs_bitmap_clear_bit(lcnbmp_na, lcn))
		ntfs_log_error("Failed to free cluster.%s\n", es);
	if (status.mp_rebuilt) {
		if (ntfs_mapping_pairs_build(vol, (u8*)a +
				le16_to_cpu(a->mapping_pairs_offset),
				old_alen - le16_to_cpu(a->mapping_pairs_offset),
				rl2, ll, NULL))
			ntfs_log_error("Failed to restore mapping "
					"pairs array.%s\n", es);
		if (ntfs_attr_record_resize(m, a, old_alen))
			ntfs_log_error("Failed to restore attribute "
					"record.%s\n", es);
		ntfs_inode_mark_dirty(ctx->ntfs_ino);
	}
	if (ctx)
		ntfs_attr_put_search_ctx(ctx);
	errno = ret;
	return -1;
}

/**
 * ntfs_mft_bitmap_extend_initialized - extend mft bitmap initialized data
 * @vol:	volume on which to extend the mft bitmap attribute
 *
 * Extend the initialized portion of the mft bitmap attribute on the ntfs
 * volume @vol by 8 bytes.
 *
 * Note:  Only changes initialized_size and data_size, i.e. requires that
 * allocated_size is big enough to fit the new initialized_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_bitmap_extend_initialized(ntfs_volume *vol)
{
	s64 old_data_size, old_initialized_size, ll;
	ntfs_attr *mftbmp_na;
	ntfs_attr_search_ctx *ctx;
	ATTR_RECORD *a;
	int err;

	mftbmp_na = vol->mftbmp_na;
	ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
	if (!ctx) {
		ntfs_log_error("Failed to get search context.\n");
		return -1;
	}
	if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name,
			mftbmp_na->name_len, 0, 0, NULL, 0, ctx)) {
		ntfs_log_error("Failed to find first attribute extent of "
				"mft bitmap attribute.\n");
		err = errno;
		goto put_err_out;
	}
	a = ctx->attr;
	old_data_size = mftbmp_na->data_size;
	old_initialized_size = mftbmp_na->initialized_size;
	mftbmp_na->initialized_size += 8;
	a->initialized_size = cpu_to_sle64(mftbmp_na->initialized_size);
	if (mftbmp_na->initialized_size > mftbmp_na->data_size) {
		mftbmp_na->data_size = mftbmp_na->initialized_size;
		a->data_size = cpu_to_sle64(mftbmp_na->data_size);
	}
	/* Ensure the changes make it to disk. */
	ntfs_inode_mark_dirty(ctx->ntfs_ino);
	ntfs_attr_put_search_ctx(ctx);
	/* Initialize the mft bitmap attribute value with zeroes. */
	ll = 0;
	ll = ntfs_attr_pwrite(mftbmp_na, old_initialized_size, 8, &ll);
	if (ll == 8) {
		ntfs_log_debug("Wrote eight initialized bytes to mft bitmap.\n");
		return 0;
	}
	ntfs_log_error("Failed to write to mft bitmap.\n");
	err = errno;
	if (ll >= 0)
		err = EIO;
	/* Try to recover from the error. */
	ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
	if (!ctx) {
		ntfs_log_error("Failed to get search context.%s\n", es);
		goto err_out;
	}
	if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name,
			mftbmp_na->name_len, 0, 0, NULL, 0, ctx)) {
		ntfs_log_error("Failed to find first attribute extent of "
				"mft bitmap attribute.%s\n", es);
put_err_out:
		ntfs_attr_put_search_ctx(ctx);
		goto err_out;
	}
	a = ctx->attr;
	mftbmp_na->initialized_size = old_initialized_size;
	a->initialized_size = cpu_to_sle64(old_initialized_size);
	if (mftbmp_na->data_size != old_data_size) {
		mftbmp_na->data_size = old_data_size;
		a->data_size = cpu_to_sle64(old_data_size);
	}
	ntfs_inode_mark_dirty(ctx->ntfs_ino);
	ntfs_attr_put_search_ctx(ctx);
	ntfs_log_debug("Restored status of mftbmp: allocated_size 0x%llx, "
			"data_size 0x%llx, initialized_size 0x%llx.\n",
			(long long)mftbmp_na->allocated_size,
			(long long)mftbmp_na->data_size,
			(long long)mftbmp_na->initialized_size);
err_out:
	errno = err;
	return -1;
}

/**
 * ntfs_mft_data_extend_allocation - extend mft data attribute
 * @vol:	volume on which to extend the mft data attribute
 *
 * Extend the mft data attribute on the ntfs volume @vol by 16 mft records
 * worth of clusters or if not enough space for this by one mft record worth
 * of clusters.
 *
 * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
 * data_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_data_extend_allocation(ntfs_volume *vol)
{
	LCN lcn;
	VCN old_last_vcn;
	s64 min_nr, nr, ll = 0; /* silence compiler warning */
	ntfs_attr *mft_na;
	runlist_element *rl, *rl2;
	ntfs_attr_search_ctx *ctx;
	MFT_RECORD *m = NULL; /* silence compiler warning */
	ATTR_RECORD *a = NULL; /* silence compiler warning */
	int err, mp_size;
	u32 old_alen = 0; /* silence compiler warning */
	BOOL mp_rebuilt = FALSE;

	ntfs_log_debug("Extending mft data allocation.\n");
	mft_na = vol->mft_na;
	/*
	 * Determine the preferred allocation location, i.e. the last lcn of
	 * the mft data attribute.  The allocated size of the mft data
	 * attribute cannot be zero so we are ok to do this.
	 */
	rl = ntfs_attr_find_vcn(mft_na,
			(mft_na->allocated_size - 1) >> vol->cluster_size_bits);
	if (!rl || !rl->length || rl->lcn < 0) {
		ntfs_log_error("Failed to determine last allocated "
				"cluster of mft data attribute.\n");
		if (rl)
			errno = EIO;
		return -1;
	}
	lcn = rl->lcn + rl->length;
	ntfs_log_debug("Last lcn of mft data attribute is 0x%llx.\n", (long long)lcn);
	/* Minimum allocation is one mft record worth of clusters. */
	min_nr = vol->mft_record_size >> vol->cluster_size_bits;
	if (!min_nr)
		min_nr = 1;
	/* Want to allocate 16 mft records worth of clusters. */
	nr = vol->mft_record_size << 4 >> vol->cluster_size_bits;
	if (!nr)
		nr = min_nr;
	ntfs_log_debug("Trying mft data allocation with default cluster count "
			"%lli.\n", (long long)nr);
	old_last_vcn = rl[1].vcn;
	do {
		rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE);
		if (rl2)
			break;
		if (errno != ENOSPC || nr == min_nr) {
			ntfs_log_error("Failed to allocate the minimal "
					"number of clusters (%lli) for the "
					"mft data attribute.\n", (long long)nr);
			return -1;
		}
		/*
		 * There is not enough space to do the allocation, but there
		 * might be enough space to do a minimal allocation so try that
		 * before failing.
		 */
		nr = min_nr;
		ntfs_log_debug("Retrying mft data allocation with minimal cluster "
				"count %lli.\n", (long long)nr);
	} while (1);
	rl = ntfs_runlists_merge(mft_na->rl, rl2);
	if (!rl) {
		err = errno;
		ntfs_log_error("Failed to merge runlists for mft data "
				"attribute.\n");
		if (ntfs_cluster_free_from_rl(vol, rl2))
			ntfs_log_error("Failed to deallocate clusters "
					"from the mft data attribute.%s\n", es);
		free(rl2);
		errno = err;
		return -1;
	}
	mft_na->rl = rl;
	ntfs_log_debug("Allocated %lli clusters.\n", nr);
	/* Find the last run in the new runlist. */
	for (; rl[1].length; rl++)
		;
	/* Update the attribute record as well. */
	ctx = ntfs_attr_get_search_ctx(mft_na->ni, NULL);
	if (!ctx) {
		ntfs_log_error("Failed to get search context.\n");
		goto undo_alloc;
	}
	if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0,
			rl[1].vcn, NULL, 0, ctx)) {
		ntfs_log_error("Failed to find last attribute extent of "
				"mft data attribute.\n");
		goto undo_alloc;
	}
	m = ctx->mrec;
	a = ctx->attr;
	ll = sle64_to_cpu(a->lowest_vcn);
	rl2 = ntfs_attr_find_vcn(mft_na, ll);