inode.c

来自「一个类似windows」· C语言 代码 · 共 2,026 行 · 第 1/5 页

		if (!lookup_attr(AT_INDEX_ALLOCATION, I30, 4, CASE_SENSITIVE,
				0, NULL, 0, ctx)) {
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
					"is not present but $INDEX_ROOT "
					"indicated it is.");
			goto unm_err_out;
		}
		if (!ctx->attr->non_resident) {
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
					"is resident.");
			goto unm_err_out;
		}
		if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
					"is encrypted.");
			goto unm_err_out;
		}
		if (ctx->attr->flags & ATTR_IS_SPARSE) {
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
					"is sparse.");
			goto unm_err_out;
		}
		if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
			ntfs_error(vi->i_sb, "$INDEX_ALLOCATION attribute "
					"is compressed.");
			goto unm_err_out;
		}
		if (ctx->attr->data.non_resident.lowest_vcn) {
			ntfs_error(vi->i_sb, "First extent of "
					"$INDEX_ALLOCATION attribute has non "
					"zero lowest_vcn. Inode is corrupt. "
					"You should run chkdsk.");
			goto unm_err_out;
		}
		vi->i_size = sle64_to_cpu(
				ctx->attr->data.non_resident.data_size);
		ni->initialized_size = sle64_to_cpu(
				ctx->attr->data.non_resident.initialized_size);
		ni->allocated_size = sle64_to_cpu(
				ctx->attr->data.non_resident.allocated_size);
		/*
		 * We are done with the mft record, so we release it. Otherwise
		 * we would deadlock in ntfs_attr_iget().
		 */
		put_attr_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 (unlikely(IS_ERR(bvi))) {
			ntfs_error(vi->i_sb, "Failed to get bitmap attribute.");
			err = PTR_ERR(bvi);
			goto unm_err_out;
		}
		ni->itype.index.bmp_ino = bvi;
		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 unm_err_out;
		}
		/* Consistency check bitmap size vs. index allocation size. */
		if ((bvi->i_size << 3) < (vi->i_size >>
				ni->itype.index.block_size_bits)) {
			ntfs_error(vi->i_sb, "Index bitmap too small (0x%Lx) "
					"for index allocation (0x%Lx).",
					bvi->i_size << 3, vi->i_size);
			goto unm_err_out;
		}
skip_large_dir_stuff:
		/* Everyone gets read and scan permissions. */
		vi->i_mode |= S_IRUGO | S_IXUGO;
		/* If not read-only, set write permissions. */
		if (!IS_RDONLY(vi))
			vi->i_mode |= S_IWUGO;
		/*
		 * Apply the directory permissions mask set in the mount
		 * options.
		 */
		vi->i_mode &= ~vol->dmask;
		/* Setup the operations for this inode. */
		vi->i_op = &ntfs_dir_inode_ops;
		vi->i_fop = &ntfs_dir_ops;
		vi->i_mapping->a_ops = &ntfs_aops;
	} else {
		/* It is a file. */
		reinit_attr_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. */
		if (!lookup_attr(AT_DATA, NULL, 0, 0, 0, NULL, 0, ctx)) {
			vi->i_size = ni->initialized_size =
					ni->allocated_size = 0LL;
			/*
			 * 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;
		}
		/* Setup the state. */
		if (ctx->attr->non_resident) {
			NInoSetNonResident(ni);
			if (ctx->attr->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 ((ctx->attr->flags & ATTR_COMPRESSION_MASK)
						!= ATTR_IS_COMPRESSED) {
					ntfs_error(vi->i_sb, "Found "
						"unknown compression method or "
						"corrupt file.");
					goto unm_err_out;
				}
				ni->itype.compressed.block_clusters = 1U <<
						ctx->attr->data.non_resident.
						compression_unit;
				if (ctx->attr->data.non_resident.
						compression_unit != 4) {
					ntfs_error(vi->i_sb, "Found "
						"nonstandard compression unit "
						"(%u instead of 4). Cannot "
						"handle this. This might "
						"indicate corruption so you "
						"should run chkdsk.",
						ctx->attr->data.non_resident.
						compression_unit);
					err = -EOPNOTSUPP;
					goto unm_err_out;
				}
				ni->itype.compressed.block_size = 1U << (
						ctx->attr->data.non_resident.
						compression_unit +
						vol->cluster_size_bits);
				ni->itype.compressed.block_size_bits = ffs(
					ni->itype.compressed.block_size) - 1;
			}
			if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
				if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
					ntfs_error(vi->i_sb, "Found encrypted "
							"and compressed data.");
					goto unm_err_out;
				}
				NInoSetEncrypted(ni);
			}
			if (ctx->attr->flags & ATTR_IS_SPARSE)
				NInoSetSparse(ni);
			if (ctx->attr->data.non_resident.lowest_vcn) {
				ntfs_error(vi->i_sb, "First extent of $DATA "
						"attribute has non zero "
						"lowest_vcn. Inode is corrupt. "
						"You should run chkdsk.");
				goto unm_err_out;
			}
			/* Setup all the sizes. */
			vi->i_size = sle64_to_cpu(
					ctx->attr->data.non_resident.data_size);
			ni->initialized_size = sle64_to_cpu(
					ctx->attr->data.non_resident.
					initialized_size);
			ni->allocated_size = sle64_to_cpu(
					ctx->attr->data.non_resident.
					allocated_size);
			if (NInoCompressed(ni)) {
				ni->itype.compressed.size = sle64_to_cpu(
						ctx->attr->data.non_resident.
						compressed_size);
			}
		} else { /* Resident attribute. */
			/*
			 * Make all sizes equal for simplicity in read code
			 * paths. FIXME: Need to keep this in mind when
			 * converting to non-resident attribute in write code
			 * path. (Probably only affects truncate().)
			 */
			vi->i_size = ni->initialized_size = ni->allocated_size =
					le32_to_cpu(
					ctx->attr->data.resident.value_length);
		}
no_data_attr_special_case:
		/* We are done with the mft record, so we release it. */
		put_attr_search_ctx(ctx);
		unmap_mft_record(ni);
		m = NULL;
		ctx = NULL;
		/* Everyone gets all permissions. */
		vi->i_mode |= S_IRWXUGO;
		/* If read-only, noone gets write permissions. */
		if (IS_RDONLY(vi))
			vi->i_mode &= ~S_IWUGO;
		/* Apply the file permissions mask set in the mount options. */
		vi->i_mode &= ~vol->fmask;
		/* Setup the operations for this inode. */
		vi->i_op = &ntfs_file_inode_ops;
		vi->i_fop = &ntfs_file_ops;
		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 (!NInoCompressed(ni))
		vi->i_blocks = ni->allocated_size >> 9;
	else
		vi->i_blocks = ni->itype.compressed.size >> 9;

	ntfs_debug("Done.");
	return 0;

unm_err_out:
	if (!err)
		err = -EIO;
	if (ctx)
		put_attr_search_ctx(ctx);
	if (m)
		unmap_mft_record(ni);
err_out:
	ntfs_error(vi->i_sb, "Failed with error code %i. Marking inode 0x%lx "
			"as bad.", -err, vi->i_ino);
	make_bad_inode(vi);
	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 the 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
 */
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_search_context *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_blksize	= base_vi->i_blksize;
	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;
	ni->seq_no	= base_ni->seq_no;

	/* 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 = get_attr_search_ctx(base_ni, m);
	if (!ctx) {
		err = -ENOMEM;
		goto unm_err_out;
	}

	/* Find the attribute. */
	if (!lookup_attr(ni->type, ni->name, ni->name_len, IGNORE_CASE, 0,
			NULL, 0, ctx))
		goto unm_err_out;

	if (!ctx->attr->non_resident) {
		if (NInoMstProtected(ni) || ctx->attr->flags) {
			ntfs_error(vi->i_sb, "Found mst protected attribute "
					"or attribute with non-zero flags but "
					"the attribute is resident (mft_no "
					"0x%lx, type 0x%x, name_len %i). "
					"Please report you saw this message "
					"to [e-mail]",
					vi->i_ino, ni->type, ni->name_len);
			goto unm_err_out;
		}
		/*
		 * Resident attribute. Make all sizes equal for simplicity in
		 * read code paths.
		 */
		vi->i_size = ni->initialized_size = ni->allocated_size =
			le32_to_cpu(ctx->attr->data.resident.value_length);
	} else {
		NInoSetNonResident(ni);
		if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
			if (NInoMstProtected(ni)) {
				ntfs_error(vi->i_sb, "Found mst protected "
						"attribute but the attribute "
						"is compressed (mft_no 0x%lx, "
						"type 0x%x, name_len %i). "
						"Please report you saw this "
						"message to linux-ntfs-dev@"
						"lists.sf.net", vi->i_ino,
						ni->type, ni->name_len);
				goto unm_err_out;
			}
			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 "
						"(mft_no 0x%lx, type 0x%x, "
						"name_len %i). Please report "
						"you saw this message to "
						"[e-mail]",
						vi->i_ino, ni->type,
						ni->name_len);
				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 ((ctx->attr->flags & ATTR_COMPRESSION_MASK)
					!= ATTR_IS_COMPRESSED) {
				ntfs_error(vi->i_sb, "Found unknown "
						"compression method or "
						"corrupt file.");
				goto unm_err_out;
			}
			ni->itype.compressed.block_clusters = 1U <<
					ctx->attr->data.non_resident.
					compression_unit;
			if (ctx->attr->data.non_resident.compression_unit != 4) {
				ntfs_error(vi->i_sb, "Found "
					"nonstandard compression unit "
					"(%u instead of 4). Cannot "
					"handle this. This might "
					"indicate corruption so you "
					"should run chkdsk.",
					ctx->attr->data.non_resident.
					compression_unit);
				err = -EOPNOTSUPP;
				goto unm_err_out;
			}
			ni->itype.compressed.block_size = 1U << (
					ctx->attr->data.non_resident.
					compression_unit +
					vol->cluster_size_bits);
			ni->itype.compressed.block_size_bits = ffs(
				ni->itype.compressed.block_size) - 1;
		}
		if (ctx->attr->flags & ATTR_IS_ENCRYPTED) {
			if (ctx->attr->flags & ATTR_COMPRESSION_MASK) {
				ntfs_error(vi->i_sb, "Found encrypted "
						"and compressed data.");
				goto unm_err_out;