inode.c

linux 内核源代码

		if (a->flags & ATTR_IS_SPARSE)
			NInoSetSparse(ni);
		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, "$INDEX_ROOT attribute is "
					"corrupt.");
			goto unm_err_out;
		}
		index_end = (u8*)&ir->index +
				le32_to_cpu(ir->index.index_length);
		if (index_end > ir_end) {
			ntfs_error(vi->i_sb, "Directory index is corrupt.");
			goto unm_err_out;
		}
		if (ir->type != AT_FILE_NAME) {
			ntfs_error(vi->i_sb, "Indexed attribute is not "
					"$FILE_NAME.");
			goto unm_err_out;
		}
		if (ir->collation_rule != COLLATION_FILE_NAME) {
			ntfs_error(vi->i_sb, "Index collation rule is not "
					"COLLATION_FILE_NAME.");
			goto unm_err_out;
		}
		ni->itype.index.collation_rule = 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 directory 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;
		}

		/* Setup the index allocation attribute, even if not present. */
		NInoSetMstProtected(ni);
		ni->type = AT_INDEX_ALLOCATION;
		ni->name = I30;
		ni->name_len = 4;

		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(ni);
			m = NULL;
			ctx = NULL;
			goto skip_large_dir_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, I30, 4,
				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 compressed.");
			goto unm_err_out;
		}
		if (a->data.non_resident.lowest_vcn) {
			ntfs_error(vi->i_sb, "First extent of "
					"$INDEX_ALLOCATION attribute has non "
					"zero lowest_vcn.");
			goto unm_err_out;
		}
		vi->i_size = sle64_to_cpu(a->data.non_resident.data_size);
		ni->initialized_size = sle64_to_cpu(
				a->data.non_resident.initialized_size);
		ni->allocated_size = sle64_to_cpu(
				a->data.non_resident.allocated_size);
		/*
		 * We are done with the mft record, so we release it. Otherwise
		 * we would deadlock in ntfs_attr_iget().
		 */
		ntfs_attr_put_search_ctx(ctx);
		unmap_mft_record(ni);
		m = NULL;
		ctx = NULL;
		/* Get the index bitmap attribute inode. */
		bvi = ntfs_attr_iget(vi, AT_BITMAP, I30, 4);
		if (IS_ERR(bvi)) {
			ntfs_error(vi->i_sb, "Failed to get bitmap attribute.");
			err = PTR_ERR(bvi);
			goto unm_err_out;
		}
		bni = NTFS_I(bvi);
		if (NInoCompressed(bni) || NInoEncrypted(bni) ||
				NInoSparse(bni)) {
			ntfs_error(vi->i_sb, "$BITMAP attribute is compressed "
					"and/or encrypted and/or sparse.");
			goto iput_unm_err_out;
		}
		/* Consistency check bitmap size vs. index allocation size. */
		bvi_size = i_size_read(bvi);
		if ((bvi_size << 3) < (vi->i_size >>
				ni->itype.index.block_size_bits)) {
			ntfs_error(vi->i_sb, "Index bitmap too small (0x%llx) "
					"for index allocation (0x%llx).",
					bvi_size << 3, vi->i_size);
			goto iput_unm_err_out;
		}
		/* No longer need the bitmap attribute inode. */
		iput(bvi);
skip_large_dir_stuff:
		/* Setup the operations for this inode. */
		vi->i_op = &ntfs_dir_inode_ops;
		vi->i_fop = &ntfs_dir_ops;
	} else {
		/* It is a file. */
		ntfs_attr_reinit_search_ctx(ctx);

		/* Setup the data attribute, even if not present. */
		ni->type = AT_DATA;
		ni->name = NULL;
		ni->name_len = 0;

		/* Find first extent of the unnamed data attribute. */
		err = ntfs_attr_lookup(AT_DATA, NULL, 0, 0, 0, NULL, 0, ctx);
		if (unlikely(err)) {
			vi->i_size = ni->initialized_size =
					ni->allocated_size = 0;
			if (err != -ENOENT) {
				ntfs_error(vi->i_sb, "Failed to lookup $DATA "
						"attribute.");
				goto unm_err_out;
			}
			/*
			 * FILE_Secure does not have an unnamed $DATA
			 * attribute, so we special case it here.
			 */
			if (vi->i_ino == FILE_Secure)
				goto no_data_attr_special_case;
			/*
			 * Most if not all the system files in the $Extend
			 * system directory do not have unnamed data
			 * attributes so we need to check if the parent
			 * directory of the file is FILE_Extend and if it is
			 * ignore this error. To do this we need to get the
			 * name of this inode from the mft record as the name
			 * contains the back reference to the parent directory.
			 */
			if (ntfs_is_extended_system_file(ctx) > 0)
				goto no_data_attr_special_case;
			// FIXME: File is corrupt! Hot-fix with empty data
			// attribute if recovery option is set.
			ntfs_error(vi->i_sb, "$DATA attribute is missing.");
			goto unm_err_out;
		}
		a = ctx->attr;
		/* Setup the state. */
		if (a->flags & (ATTR_COMPRESSION_MASK | ATTR_IS_SPARSE)) {
			if (a->flags & ATTR_COMPRESSION_MASK) {
				NInoSetCompressed(ni);
				if (vol->cluster_size > 4096) {
					ntfs_error(vi->i_sb, "Found "
							"compressed data 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 "
							"or corrupt file.");
					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;
			}
			NInoSetEncrypted(ni);
		}
		if (a->non_resident) {
			NInoSetNonResident(ni);
			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 $DATA "
						"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);
		} else { /* Resident attribute. */
			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 data attribute "
						"is corrupt (size exceeds "
						"allocation).");
				goto unm_err_out;
			}
		}
no_data_attr_special_case:
		/* We are done with the mft record, so we release it. */
		ntfs_attr_put_search_ctx(ctx);
		unmap_mft_record(ni);
		m = NULL;
		ctx = NULL;
		/* Setup the operations for this inode. */
		vi->i_op = &ntfs_file_inode_ops;
		vi->i_fop = &ntfs_file_ops;
	}
	if (NInoMstProtected(ni))
		vi->i_mapping->a_ops = &ntfs_mst_aops;
	else
		vi->i_mapping->a_ops = &ntfs_aops;
	/*
	 * The number of 512-byte blocks used on disk (for stat). This is in so
	 * far inaccurate as it doesn't account for any named streams or other
	 * special non-resident attributes, but that is how Windows works, too,
	 * so we are at least consistent with Windows, if not entirely
	 * consistent with the Linux Way. Doing it the Linux Way would cause a
	 * significant slowdown as it would involve iterating over all
	 * attributes in the mft record and adding the allocated/compressed
	 * sizes of all non-resident attributes present to give us the Linux
	 * correct size that should go into i_blocks (after division by 512).
	 */
	if (S_ISREG(vi->i_mode) && (NInoCompressed(ni) || NInoSparse(ni)))
		vi->i_blocks = ni->itype.compressed.size >> 9;
	else
		vi->i_blocks = ni->allocated_size >> 9;
	ntfs_debug("Done.");
	return 0;
iput_unm_err_out:
	iput(bvi);
unm_err_out:
	if (!err)
		err = -EIO;
	if (ctx)
		ntfs_attr_put_search_ctx(ctx);
	if (m)
		unmap_mft_record(ni);
err_out:
	ntfs_error(vol->sb, "Failed with error code %i.  Marking corrupt "
			"inode 0x%lx as bad.  Run chkdsk.", err, vi->i_ino);
	make_bad_inode(vi);
	if (err != -EOPNOTSUPP && err != -ENOMEM)
		NVolSetErrors(vol);
	return err;
}

/**
 * ntfs_read_locked_attr_inode - read an attribute inode from its base inode
 * @base_vi:	base inode
 * @vi:		attribute inode to read
 *
 * ntfs_read_locked_attr_inode() is called from ntfs_attr_iget() to read the
 * attribute inode described by @vi into memory from the base mft record
 * described by @base_ni.
 *
 * ntfs_read_locked_attr_inode() maps, pins and locks the base inode for
 * reading and looks up the attribute described by @vi before setting up the
 * necessary fields in @vi as well as initializing the ntfs inode.
 *
 * 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.
 *
 * Note this cannot be called for AT_INDEX_ALLOCATION.
 */
static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
{
	ntfs_volume *vol = NTFS_SB(vi->i_sb);
	ntfs_inode *ni, *base_ni;
	MFT_RECORD *m;
	ATTR_RECORD *a;
	ntfs_attr_search_ctx *ctx;
	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;