inode.c

linux 内核源代码

	/* Set inode type to zero but preserve permissions. */
	vi->i_mode	= base_vi->i_mode & ~S_IFMT;

	m = map_mft_record(base_ni);
	if (IS_ERR(m)) {
		err = PTR_ERR(m);
		goto err_out;
	}
	ctx = ntfs_attr_get_search_ctx(base_ni, m);
	if (!ctx) {
		err = -ENOMEM;
		goto unm_err_out;
	}
	/* Find the attribute. */
	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
			CASE_SENSITIVE, 0, NULL, 0, ctx);
	if (unlikely(err))
		goto unm_err_out;
	a = ctx->attr;
	if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_SPARSE)) {
		if (a->flags & ATTR_COMPRESSION_MASK) {
			NInoSetCompressed(ni);
			if ((ni->type != AT_DATA) || (ni->type == AT_DATA &&
					ni->name_len)) {
				ntfs_error(vi->i_sb, "Found compressed "
						"non-data or named data "
						"attribute.  Please report "
						"you saw this message to "
						"linux-ntfs-dev@lists."
						"sourceforge.net");
				goto unm_err_out;
			}
			if (vol->cluster_size > 4096) {
				ntfs_error(vi->i_sb, "Found compressed "
						"attribute but compression is "
						"disabled due to cluster size "
						"(%i) > 4kiB.",
						vol->cluster_size);
				goto unm_err_out;
			}
			if ((a->flags & ATTR_COMPRESSION_MASK) !=
					ATTR_IS_COMPRESSED) {
				ntfs_error(vi->i_sb, "Found unknown "
						"compression method.");
				goto unm_err_out;
			}
		}
		/*
		 * The compressed/sparse flag set in an index root just means
		 * to compress all files.
		 */
		if (NInoMstProtected(ni) && ni->type != AT_INDEX_ROOT) {
			ntfs_error(vi->i_sb, "Found mst protected attribute "
					"but the attribute is %s.  Please "
					"report you saw this message to "
					"[e-mail]",
					NInoCompressed(ni) ? "compressed" :
					"sparse");
			goto unm_err_out;
		}
		if (a->flags & ATTR_IS_SPARSE)
			NInoSetSparse(ni);
	}
	if (a->flags & ATTR_IS_ENCRYPTED) {
		if (NInoCompressed(ni)) {
			ntfs_error(vi->i_sb, "Found encrypted and compressed "
					"data.");
			goto unm_err_out;
		}
		/*
		 * The encryption flag set in an index root just means to
		 * encrypt all files.
		 */
		if (NInoMstProtected(ni) && ni->type != AT_INDEX_ROOT) {
			ntfs_error(vi->i_sb, "Found mst protected attribute "
					"but the attribute is encrypted.  "
					"Please report you saw this message "
					"to [e-mail]."
					"net");
			goto unm_err_out;
		}
		if (ni->type != AT_DATA) {
			ntfs_error(vi->i_sb, "Found encrypted non-data "
					"attribute.");
			goto unm_err_out;
		}
		NInoSetEncrypted(ni);
	}
	if (!a->non_resident) {
		/* Ensure the attribute name is placed before the value. */
		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
				le16_to_cpu(a->data.resident.value_offset)))) {
			ntfs_error(vol->sb, "Attribute name is placed after "
					"the attribute value.");
			goto unm_err_out;
		}
		if (NInoMstProtected(ni)) {
			ntfs_error(vi->i_sb, "Found mst protected attribute "
					"but the attribute is resident.  "
					"Please report you saw this message to "
					"[e-mail]");
			goto unm_err_out;
		}
		vi->i_size = ni->initialized_size = le32_to_cpu(
				a->data.resident.value_length);
		ni->allocated_size = le32_to_cpu(a->length) -
				le16_to_cpu(a->data.resident.value_offset);
		if (vi->i_size > ni->allocated_size) {
			ntfs_error(vi->i_sb, "Resident attribute is corrupt "
					"(size exceeds allocation).");
			goto unm_err_out;
		}
	} else {
		NInoSetNonResident(ni);
		/*
		 * Ensure the attribute name is placed before the mapping pairs
		 * array.
		 */
		if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
				le16_to_cpu(
				a->data.non_resident.mapping_pairs_offset)))) {
			ntfs_error(vol->sb, "Attribute name is placed after "
					"the mapping pairs array.");
			goto unm_err_out;
		}
		if (NInoCompressed(ni) || NInoSparse(ni)) {
			if (NInoCompressed(ni) && a->data.non_resident.
					compression_unit != 4) {
				ntfs_error(vi->i_sb, "Found non-standard "
						"compression unit (%u instead "
						"of 4).  Cannot handle this.",
						a->data.non_resident.
						compression_unit);
				err = -EOPNOTSUPP;
				goto unm_err_out;
			}
			if (a->data.non_resident.compression_unit) {
				ni->itype.compressed.block_size = 1U <<
						(a->data.non_resident.
						compression_unit +
						vol->cluster_size_bits);
				ni->itype.compressed.block_size_bits =
						ffs(ni->itype.compressed.
						block_size) - 1;
				ni->itype.compressed.block_clusters = 1U <<
						a->data.non_resident.
						compression_unit;
			} else {
				ni->itype.compressed.block_size = 0;
				ni->itype.compressed.block_size_bits = 0;
				ni->itype.compressed.block_clusters = 0;
			}
			ni->itype.compressed.size = sle64_to_cpu(
					a->data.non_resident.compressed_size);
		}
		if (a->data.non_resident.lowest_vcn) {
			ntfs_error(vi->i_sb, "First extent of attribute has "
					"non-zero lowest_vcn.");
			goto unm_err_out;
		}
		vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
		ni->initialized_size = sle64_to_cpu(
				a->data.non_resident.initialized_size);
		ni->allocated_size = sle64_to_cpu(
				a->data.non_resident.allocated_size);
	}
	/* Setup the operations for this attribute inode. */
	vi->i_op = NULL;
	vi->i_fop = NULL;
	if (NInoMstProtected(ni))
		vi->i_mapping->a_ops = &ntfs_mst_aops;
	else
		vi->i_mapping->a_ops = &ntfs_aops;
	if ((NInoCompressed(ni) || NInoSparse(ni)) && ni->type != AT_INDEX_ROOT)
		vi->i_blocks = ni->itype.compressed.size >> 9;
	else
		vi->i_blocks = ni->allocated_size >> 9;
	/*
	 * Make sure the base inode does not go away and attach it to the
	 * attribute inode.
	 */
	igrab(base_vi);
	ni->ext.base_ntfs_ino = base_ni;
	ni->nr_extents = -1;

	ntfs_attr_put_search_ctx(ctx);
	unmap_mft_record(base_ni);

	ntfs_debug("Done.");
	return 0;

unm_err_out:
	if (!err)
		err = -EIO;
	if (ctx)
		ntfs_attr_put_search_ctx(ctx);
	unmap_mft_record(base_ni);
err_out:
	ntfs_error(vol->sb, "Failed with error code %i while reading attribute "
			"inode (mft_no 0x%lx, type 0x%x, name_len %i).  "
			"Marking corrupt inode and base inode 0x%lx as bad.  "
			"Run chkdsk.", err, vi->i_ino, ni->type, ni->name_len,
			base_vi->i_ino);
	make_bad_inode(vi);
	if (err != -ENOMEM)
		NVolSetErrors(vol);
	return err;
}

/**
 * ntfs_read_locked_index_inode - read an index inode from its base inode
 * @base_vi:	base inode
 * @vi:		index inode to read
 *
 * ntfs_read_locked_index_inode() is called from ntfs_index_iget() to read the
 * index inode described by @vi into memory from the base mft record described
 * by @base_ni.
 *
 * ntfs_read_locked_index_inode() maps, pins and locks the base inode for
 * reading and looks up the attributes relating to the index described by @vi
 * before setting up the necessary fields in @vi as well as initializing the
 * ntfs inode.
 *
 * Note, index inodes are essentially attribute inodes (NInoAttr() is true)
 * with the attribute type set to AT_INDEX_ALLOCATION.  Apart from that, they
 * are setup like directory inodes since directories are a special case of
 * indices ao they need to be treated in much the same way.  Most importantly,
 * for small indices the index allocation attribute might not actually exist.
 * However, the index root attribute always exists but this does not need to
 * have an inode associated with it and this is why we define a new inode type
 * index.  Also, like for directories, we need to have an attribute inode for
 * the bitmap attribute corresponding to the index allocation attribute and we
 * can store this in the appropriate field of the inode, just like we do for
 * normal directory inodes.
 *
 * Q: What locks are held when the function is called?
 * A: i_state has I_LOCK set, hence the inode is locked, also
 *    i_count is set to 1, so it is not going to go away
 *
 * Return 0 on success and -errno on error.  In the error case, the inode will
 * have had make_bad_inode() executed on it.
 */
static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
{
	loff_t bvi_size;
	ntfs_volume *vol = NTFS_SB(vi->i_sb);
	ntfs_inode *ni, *base_ni, *bni;
	struct inode *bvi;
	MFT_RECORD *m;
	ATTR_RECORD *a;
	ntfs_attr_search_ctx *ctx;
	INDEX_ROOT *ir;
	u8 *ir_end, *index_end;
	int err = 0;

	ntfs_debug("Entering for i_ino 0x%lx.", vi->i_ino);
	ntfs_init_big_inode(vi);
	ni	= NTFS_I(vi);
	base_ni = NTFS_I(base_vi);
	/* Just mirror the values from the base inode. */
	vi->i_version	= base_vi->i_version;
	vi->i_uid	= base_vi->i_uid;
	vi->i_gid	= base_vi->i_gid;
	vi->i_nlink	= base_vi->i_nlink;
	vi->i_mtime	= base_vi->i_mtime;
	vi->i_ctime	= base_vi->i_ctime;
	vi->i_atime	= base_vi->i_atime;
	vi->i_generation = ni->seq_no = base_ni->seq_no;
	/* Set inode type to zero but preserve permissions. */
	vi->i_mode	= base_vi->i_mode & ~S_IFMT;
	/* Map the mft record for the base inode. */
	m = map_mft_record(base_ni);
	if (IS_ERR(m)) {
		err = PTR_ERR(m);
		goto err_out;
	}
	ctx = ntfs_attr_get_search_ctx(base_ni, m);
	if (!ctx) {
		err = -ENOMEM;
		goto unm_err_out;
	}
	/* Find the index root attribute. */
	err = ntfs_attr_lookup(AT_INDEX_ROOT, ni->name, ni->name_len,
			CASE_SENSITIVE, 0, NULL, 0, ctx);
	if (unlikely(err)) {
		if (err == -ENOENT)
			ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is "
					"missing.");
		goto unm_err_out;
	}
	a = ctx->attr;
	/* Set up the state. */
	if (unlikely(a->non_resident)) {
		ntfs_error(vol->sb, "$INDEX_ROOT attribute is not resident.");
		goto unm_err_out;
	}
	/* Ensure the attribute name is placed before the value. */
	if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
			le16_to_cpu(a->data.resident.value_offset)))) {
		ntfs_error(vol->sb, "$INDEX_ROOT attribute name is placed "
				"after the attribute value.");
		goto unm_err_out;
	}
	/*
	 * Compressed/encrypted/sparse index root is not allowed, except for
	 * directories of course but those are not dealt with here.
	 */
	if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_ENCRYPTED |
			ATTR_IS_SPARSE)) {
		ntfs_error(vi->i_sb, "Found compressed/encrypted/sparse index "
				"root attribute.");
		goto unm_err_out;
	}
	ir = (INDEX_ROOT*)((u8*)a + le16_to_cpu(a->data.resident.value_offset));
	ir_end = (u8*)ir + le32_to_cpu(a->data.resident.value_length);
	if (ir_end > (u8*)ctx->mrec + vol->mft_record_size) {
		ntfs_error(vi->i_sb, "$INDEX_ROOT attribute is corrupt.");
		goto unm_err_out;
	}
	index_end = (u8*)&ir->index + le32_to_cpu(ir->index.index_length);
	if (index_end > ir_end) {
		ntfs_error(vi->i_sb, "Index is corrupt.");
		goto unm_err_out;
	}
	if (ir->type) {
		ntfs_error(vi->i_sb, "Index type is not 0 (type is 0x%x).",
				le32_to_cpu(ir->type));
		goto unm_err_out;
	}
	ni->itype.index.collation_rule = ir->collation_rule;
	ntfs_debug("Index collation rule is 0x%x.",
			le32_to_cpu(ir->collation_rule));
	ni->itype.index.block_size = le32_to_cpu(ir->index_block_size);
	if (ni->itype.index.block_size & (ni->itype.index.block_size - 1)) {
		ntfs_error(vi->i_sb, "Index block size (%u) is not a power of "
				"two.", ni->itype.index.block_size);
		goto unm_err_out;
	}
	if (ni->itype.index.block_size > PAGE_CACHE_SIZE) {
		ntfs_error(vi->i_sb, "Index block size (%u) > PAGE_CACHE_SIZE "
				"(%ld) is not supported.  Sorry.",
				ni->itype.index.block_size, PAGE_CACHE_SIZE);
		err = -EOPNOTSUPP;
		goto unm_err_out;
	}
	if (ni->itype.index.block_size < NTFS_BLOCK_SIZE) {
		ntfs_error(vi->i_sb, "Index block size (%u) < NTFS_BLOCK_SIZE "
				"(%i) is not supported.  Sorry.",
				ni->itype.index.block_size, NTFS_BLOCK_SIZE);
		err = -EOPNOTSUPP;
		goto unm_err_out;
	}
	ni->itype.index.block_size_bits = ffs(ni->itype.index.block_size) - 1;
	/* Determine the size of a vcn in the index. */
	if (vol->cluster_size <= ni->itype.index.block_size) {
		ni->itype.index.vcn_size = vol->cluster_size;
		ni->itype.index.vcn_size_bits = vol->cluster_size_bits;
	} else {
		ni->itype.index.vcn_size = vol->sector_size;
		ni->itype.index.vcn_size_bits = vol->sector_size_bits;
	}
	/* Check for presence of index allocation attribute. */
	if (!(ir->index.flags & LARGE_INDEX)) {
		/* No index allocation. */
		vi->i_size = ni->initialized_size = ni->allocated_size = 0;
		/* We are done with the mft record, so we release it. */
		ntfs_attr_put_search_ctx(ctx);
		unmap_mft_record(base_ni);
		m = NULL;
		ctx = NULL;
		goto skip_large_index_stuff;
	} /* LARGE_INDEX:  Index allocation present.  Setup state. */
	NInoSetIndexAllocPresent(ni);
	/* Find index allocation attribute. */
	ntfs_attr_reinit_search_ctx(ctx);
	err = ntfs_attr_lookup(AT_INDEX_ALLOCATION, ni->name, ni->name_len,
			CASE_SENSITIVE, 0, NULL, 0, ctx);
	if (unlikely(err)) {
		if (err == -ENOENT)
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
					"not present but $INDEX_ROOT "
					"indicated it is.");
		else
			ntfs_error(vi->i_sb, "Failed to lookup "
					"$INDEX_ALLOCATION attribute.");
		goto unm_err_out;
	}
	a = ctx->attr;
	if (!a->non_resident) {
		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
				"resident.");
		goto unm_err_out;
	}
	/*
	 * Ensure the attribute name is placed before the mapping pairs array.
	 */
	if (unlikely(a->name_length && (le16_to_cpu(a->name_offset) >=
			le16_to_cpu(
			a->data.non_resident.mapping_pairs_offset)))) {
		ntfs_error(vol->sb, "$INDEX_ALLOCATION attribute name is "
				"placed after the mapping pairs array.");
		goto unm_err_out;
	}
	if (a->flags & ATTR_IS_ENCRYPTED) {
		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "
				"encrypted.");
		goto unm_err_out;
	}
	if (a->flags & ATTR_IS_SPARSE) {
		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is sparse.");
		goto unm_err_out;
	}
	if (a->flags & ATTR_COMPRESSION_MASK) {
		ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute is "