mft.c

linux 内核源代码

		ntfs_error(vol->sb, "Failed to free allocated cluster.%s", es);
		NVolSetErrors(vol);
	}
	up_write(&vol->lcnbmp_lock);
	if (status.mp_rebuilt) {
		if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
				a->data.non_resident.mapping_pairs_offset),
				old_alen - le16_to_cpu(
				a->data.non_resident.mapping_pairs_offset),
				rl2, ll, -1, NULL)) {
			ntfs_error(vol->sb, "Failed to restore mapping pairs "
					"array.%s", es);
			NVolSetErrors(vol);
		}
		if (ntfs_attr_record_resize(ctx->mrec, a, old_alen)) {
			ntfs_error(vol->sb, "Failed to restore attribute "
					"record.%s", es);
			NVolSetErrors(vol);
		}
		flush_dcache_mft_record_page(ctx->ntfs_ino);
		mark_mft_record_dirty(ctx->ntfs_ino);
	}
	if (ctx)
		ntfs_attr_put_search_ctx(ctx);
	if (!IS_ERR(mrec))
		unmap_mft_record(mft_ni);
	up_write(&mftbmp_ni->runlist.lock);
	return ret;
}

/**
 * ntfs_mft_bitmap_extend_initialized_nolock - extend mftbmp 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 -error on error.
 *
 * Locking: Caller must hold vol->mftbmp_lock for writing.
 */
static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
{
	s64 old_data_size, old_initialized_size;
	unsigned long flags;
	struct inode *mftbmp_vi;
	ntfs_inode *mft_ni, *mftbmp_ni;
	ntfs_attr_search_ctx *ctx;
	MFT_RECORD *mrec;
	ATTR_RECORD *a;
	int ret;

	ntfs_debug("Extending mft bitmap initiailized (and data) size.");
	mft_ni = NTFS_I(vol->mft_ino);
	mftbmp_vi = vol->mftbmp_ino;
	mftbmp_ni = NTFS_I(mftbmp_vi);
	/* Get the attribute record. */
	mrec = map_mft_record(mft_ni);
	if (IS_ERR(mrec)) {
		ntfs_error(vol->sb, "Failed to map mft record.");
		return PTR_ERR(mrec);
	}
	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
	if (unlikely(!ctx)) {
		ntfs_error(vol->sb, "Failed to get search context.");
		ret = -ENOMEM;
		goto unm_err_out;
	}
	ret = ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
			mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx);
	if (unlikely(ret)) {
		ntfs_error(vol->sb, "Failed to find first attribute extent of "
				"mft bitmap attribute.");
		if (ret == -ENOENT)
			ret = -EIO;
		goto put_err_out;
	}
	a = ctx->attr;
	write_lock_irqsave(&mftbmp_ni->size_lock, flags);
	old_data_size = i_size_read(mftbmp_vi);
	old_initialized_size = mftbmp_ni->initialized_size;
	/*
	 * We can simply update the initialized_size before filling the space
	 * with zeroes because the caller is holding the mft bitmap lock for
	 * writing which ensures that no one else is trying to access the data.
	 */
	mftbmp_ni->initialized_size += 8;
	a->data.non_resident.initialized_size =
			cpu_to_sle64(mftbmp_ni->initialized_size);
	if (mftbmp_ni->initialized_size > old_data_size) {
		i_size_write(mftbmp_vi, mftbmp_ni->initialized_size);
		a->data.non_resident.data_size =
				cpu_to_sle64(mftbmp_ni->initialized_size);
	}
	write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
	/* Ensure the changes make it to disk. */
	flush_dcache_mft_record_page(ctx->ntfs_ino);
	mark_mft_record_dirty(ctx->ntfs_ino);
	ntfs_attr_put_search_ctx(ctx);
	unmap_mft_record(mft_ni);
	/* Initialize the mft bitmap attribute value with zeroes. */
	ret = ntfs_attr_set(mftbmp_ni, old_initialized_size, 8, 0);
	if (likely(!ret)) {
		ntfs_debug("Done.  (Wrote eight initialized bytes to mft "
				"bitmap.");
		return 0;
	}
	ntfs_error(vol->sb, "Failed to write to mft bitmap.");
	/* Try to recover from the error. */
	mrec = map_mft_record(mft_ni);
	if (IS_ERR(mrec)) {
		ntfs_error(vol->sb, "Failed to map mft record.%s", es);
		NVolSetErrors(vol);
		return ret;
	}
	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
	if (unlikely(!ctx)) {
		ntfs_error(vol->sb, "Failed to get search context.%s", es);
		NVolSetErrors(vol);
		goto unm_err_out;
	}
	if (ntfs_attr_lookup(mftbmp_ni->type, mftbmp_ni->name,
			mftbmp_ni->name_len, CASE_SENSITIVE, 0, NULL, 0, ctx)) {
		ntfs_error(vol->sb, "Failed to find first attribute extent of "
				"mft bitmap attribute.%s", es);
		NVolSetErrors(vol);
put_err_out:
		ntfs_attr_put_search_ctx(ctx);
unm_err_out:
		unmap_mft_record(mft_ni);
		goto err_out;
	}
	a = ctx->attr;
	write_lock_irqsave(&mftbmp_ni->size_lock, flags);
	mftbmp_ni->initialized_size = old_initialized_size;
	a->data.non_resident.initialized_size =
			cpu_to_sle64(old_initialized_size);
	if (i_size_read(mftbmp_vi) != old_data_size) {
		i_size_write(mftbmp_vi, old_data_size);
		a->data.non_resident.data_size = cpu_to_sle64(old_data_size);
	}
	write_unlock_irqrestore(&mftbmp_ni->size_lock, 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(mft_ni);
#ifdef DEBUG
	read_lock_irqsave(&mftbmp_ni->size_lock, flags);
	ntfs_debug("Restored status of mftbmp: allocated_size 0x%llx, "
			"data_size 0x%llx, initialized_size 0x%llx.",
			(long long)mftbmp_ni->allocated_size,
			(long long)i_size_read(mftbmp_vi),
			(long long)mftbmp_ni->initialized_size);
	read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
#endif /* DEBUG */
err_out:
	return ret;
}

/**
 * ntfs_mft_data_extend_allocation_nolock - 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 -errno on error.
 *
 * Locking: - Caller must hold vol->mftbmp_lock for writing.
 *	    - This function takes NTFS_I(vol->mft_ino)->runlist.lock for
 *	      writing and releases it before returning.
 *	    - This function calls functions which take vol->lcnbmp_lock for
 *	      writing and release it before returning.
 */
static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
{
	LCN lcn;
	VCN old_last_vcn;
	s64 min_nr, nr, ll;
	unsigned long flags;
	ntfs_inode *mft_ni;
	runlist_element *rl, *rl2;
	ntfs_attr_search_ctx *ctx = NULL;
	MFT_RECORD *mrec;
	ATTR_RECORD *a = NULL;
	int ret, mp_size;
	u32 old_alen = 0;
	bool mp_rebuilt = false;

	ntfs_debug("Extending mft data allocation.");
	mft_ni = NTFS_I(vol->mft_ino);
	/*
	 * 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.
	 */
	down_write(&mft_ni->runlist.lock);
	read_lock_irqsave(&mft_ni->size_lock, flags);
	ll = mft_ni->allocated_size;
	read_unlock_irqrestore(&mft_ni->size_lock, flags);
	rl = ntfs_attr_find_vcn_nolock(mft_ni,
			(ll - 1) >> vol->cluster_size_bits, NULL);
	if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
		up_write(&mft_ni->runlist.lock);
		ntfs_error(vol->sb, "Failed to determine last allocated "
				"cluster of mft data attribute.");
		if (!IS_ERR(rl))
			ret = -EIO;
		else
			ret = PTR_ERR(rl);
		return ret;
	}
	lcn = rl->lcn + rl->length;
	ntfs_debug("Last lcn of mft data attribute is 0x%llx.", (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;
	/* Ensure we do not go above 2^32-1 mft records. */
	read_lock_irqsave(&mft_ni->size_lock, flags);
	ll = mft_ni->allocated_size;
	read_unlock_irqrestore(&mft_ni->size_lock, flags);
	if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
			vol->mft_record_size_bits >= (1ll << 32))) {
		nr = min_nr;
		if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
				vol->mft_record_size_bits >= (1ll << 32))) {
			ntfs_warning(vol->sb, "Cannot allocate mft record "
					"because the maximum number of inodes "
					"(2^32) has already been reached.");
			up_write(&mft_ni->runlist.lock);
			return -ENOSPC;
		}
	}
	ntfs_debug("Trying mft data allocation with %s cluster count %lli.",
			nr > min_nr ? "default" : "minimal", (long long)nr);
	old_last_vcn = rl[1].vcn;
	do {
		rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE,
				true);
		if (likely(!IS_ERR(rl2)))
			break;
		if (PTR_ERR(rl2) != -ENOSPC || nr == min_nr) {
			ntfs_error(vol->sb, "Failed to allocate the minimal "
					"number of clusters (%lli) for the "
					"mft data attribute.", (long long)nr);
			up_write(&mft_ni->runlist.lock);
			return PTR_ERR(rl2);
		}
		/*
		 * 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_debug("Retrying mft data allocation with minimal cluster "
				"count %lli.", (long long)nr);
	} while (1);
	rl = ntfs_runlists_merge(mft_ni->runlist.rl, rl2);
	if (IS_ERR(rl)) {
		up_write(&mft_ni->runlist.lock);
		ntfs_error(vol->sb, "Failed to merge runlists for mft data "
				"attribute.");
		if (ntfs_cluster_free_from_rl(vol, rl2)) {
			ntfs_error(vol->sb, "Failed to dealocate clusters "
					"from the mft data attribute.%s", es);
			NVolSetErrors(vol);
		}
		ntfs_free(rl2);
		return PTR_ERR(rl);
	}
	mft_ni->runlist.rl = rl;
	ntfs_debug("Allocated %lli clusters.", (long long)nr);
	/* Find the last run in the new runlist. */
	for (; rl[1].length; rl++)
		;
	/* Update the attribute record as well. */
	mrec = map_mft_record(mft_ni);
	if (IS_ERR(mrec)) {
		ntfs_error(vol->sb, "Failed to map mft record.");
		ret = PTR_ERR(mrec);
		goto undo_alloc;
	}
	ctx = ntfs_attr_get_search_ctx(mft_ni, mrec);
	if (unlikely(!ctx)) {
		ntfs_error(vol->sb, "Failed to get search context.");
		ret = -ENOMEM;
		goto undo_alloc;
	}
	ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name, mft_ni->name_len,
			CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx);
	if (unlikely(ret)) {
		ntfs_error(vol->sb, "Failed to find last attribute extent of "
				"mft data attribute.");
		if (ret == -ENOENT)
			ret = -EIO;
		goto undo_alloc;
	}
	a = ctx->attr;
	ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
	/* Search back for the previous last allocated cluster of mft bitmap. */
	for (rl2 = rl; rl2 > mft_ni->runlist.rl; rl2--) {
		if (ll >= rl2->vcn)
			break;
	}
	BUG_ON(ll < rl2->vcn);
	BUG_ON(ll >= rl2->vcn + rl2->length);
	/* Get the size for the new mapping pairs array for this extent. */
	mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
	if (unlikely(mp_size <= 0)) {
		ntfs_error(vol->sb, "Get size for mapping pairs failed for "
				"mft data attribute extent.");
		ret = mp_size;
		if (!ret)
			ret = -EIO;
		goto undo_alloc;
	}
	/* Expand the attribute record if necessary. */
	old_alen = le32_to_cpu(a->length);
	ret = ntfs_attr_record_resize(ctx->mrec, a, mp_size +
			le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
	if (unlikely(ret)) {
		if (ret != -ENOSPC) {
			ntfs_error(vol->sb, "Failed to resize attribute "
					"record for mft data attribute.");
			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 or by
		// moving other attributes out of this mft record.
		// Note: Use the special reserved mft records and ensure that
		// this extent is not required to find the mft record in
		// question.  If no free special records left we would need to
		// move an existing record away, insert ours in its place, and
		// then place the moved record into the newly allocated space
		// and we would then need to update all references to this mft
		// record appropriately.  This is rather complicated...
		ntfs_error(vol->sb, "Not enough space in this mft record to "
				"accomodate extended mft data attribute "
				"extent.  Cannot handle this yet.");
		ret = -EOPNOTSUPP;
		goto undo_alloc;
	}
	mp_rebuilt = true;
	/* Generate the mapping pairs array directly into the attr record. */
	ret = ntfs_mapping_pairs_build(vol, (u8*)a +
			le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
			mp_size, rl2, ll, -1, NULL);
	if (unlikely(ret)) {
		ntfs_error(vol->sb, "Failed to build mapping pairs array of "
				"mft data attribute.");
		goto undo_alloc;
	}
	/* Update the highest_vcn. */
	a->data.non_resident.highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
	/*
	 * We now have extended the mft data allocated_size by nr clusters.
	 * Reflect this in the ntfs_inode structure and the attribute record.
	 * @rl is the last (non-terminator) runlist element of mft data
	 * attribute.
	 */
	if (a->data.non_resident.lowest_vcn) {
		/*
		 * We are not in the first attribute extent, switch to it, but
		 * first ensure the changes will make it to disk later.
		 */
		flush_dcache_mft_record_page(ctx->ntfs_ino);
		mark_mft_record_dirty(ctx->ntfs_ino);
		ntfs_attr_reinit_search_ctx(ctx);
		ret = ntfs_attr_lookup(mft_ni->type, mft_ni->name,
				mft_ni->name_len, CASE_SENSITIVE, 0, NULL, 0,
				ctx)