inode.c

linux 内核源代码

 * is still mapped. Teach this nesting to the lock validator by creating
 * a separate class for nested inode's mrec_lock's:
 */
static struct lock_class_key extent_inode_mrec_lock_key;

inline ntfs_inode *ntfs_new_extent_inode(struct super_block *sb,
		unsigned long mft_no)
{
	ntfs_inode *ni = ntfs_alloc_extent_inode();

	ntfs_debug("Entering.");
	if (likely(ni != NULL)) {
		__ntfs_init_inode(sb, ni);
		lockdep_set_class(&ni->mrec_lock, &extent_inode_mrec_lock_key);
		ni->mft_no = mft_no;
		ni->type = AT_UNUSED;
		ni->name = NULL;
		ni->name_len = 0;
	}
	return ni;
}

/**
 * ntfs_is_extended_system_file - check if a file is in the $Extend directory
 * @ctx:	initialized attribute search context
 *
 * Search all file name attributes in the inode described by the attribute
 * search context @ctx and check if any of the names are in the $Extend system
 * directory.
 *
 * Return values:
 *	   1: file is in $Extend directory
 *	   0: file is not in $Extend directory
 *    -errno: failed to determine if the file is in the $Extend directory
 */
static int ntfs_is_extended_system_file(ntfs_attr_search_ctx *ctx)
{
	int nr_links, err;

	/* Restart search. */
	ntfs_attr_reinit_search_ctx(ctx);

	/* Get number of hard links. */
	nr_links = le16_to_cpu(ctx->mrec->link_count);

	/* Loop through all hard links. */
	while (!(err = ntfs_attr_lookup(AT_FILE_NAME, NULL, 0, 0, 0, NULL, 0,
			ctx))) {
		FILE_NAME_ATTR *file_name_attr;
		ATTR_RECORD *attr = ctx->attr;
		u8 *p, *p2;

		nr_links--;
		/*
		 * Maximum sanity checking as we are called on an inode that
		 * we suspect might be corrupt.
		 */
		p = (u8*)attr + le32_to_cpu(attr->length);
		if (p < (u8*)ctx->mrec || (u8*)p > (u8*)ctx->mrec +
				le32_to_cpu(ctx->mrec->bytes_in_use)) {
err_corrupt_attr:
			ntfs_error(ctx->ntfs_ino->vol->sb, "Corrupt file name "
					"attribute. You should run chkdsk.");
			return -EIO;
		}
		if (attr->non_resident) {
			ntfs_error(ctx->ntfs_ino->vol->sb, "Non-resident file "
					"name. You should run chkdsk.");
			return -EIO;
		}
		if (attr->flags) {
			ntfs_error(ctx->ntfs_ino->vol->sb, "File name with "
					"invalid flags. You should run "
					"chkdsk.");
			return -EIO;
		}
		if (!(attr->data.resident.flags & RESIDENT_ATTR_IS_INDEXED)) {
			ntfs_error(ctx->ntfs_ino->vol->sb, "Unindexed file "
					"name. You should run chkdsk.");
			return -EIO;
		}
		file_name_attr = (FILE_NAME_ATTR*)((u8*)attr +
				le16_to_cpu(attr->data.resident.value_offset));
		p2 = (u8*)attr + le32_to_cpu(attr->data.resident.value_length);
		if (p2 < (u8*)attr || p2 > p)
			goto err_corrupt_attr;
		/* This attribute is ok, but is it in the $Extend directory? */
		if (MREF_LE(file_name_attr->parent_directory) == FILE_Extend)
			return 1;	/* YES, it's an extended system file. */
	}
	if (unlikely(err != -ENOENT))
		return err;
	if (unlikely(nr_links)) {
		ntfs_error(ctx->ntfs_ino->vol->sb, "Inode hard link count "
				"doesn't match number of name attributes. You "
				"should run chkdsk.");
		return -EIO;
	}
	return 0;	/* NO, it is not an extended system file. */
}

/**
 * ntfs_read_locked_inode - read an inode from its device
 * @vi:		inode to read
 *
 * ntfs_read_locked_inode() is called from ntfs_iget() to read the inode
 * described by @vi into memory from the device.
 *
 * The only fields in @vi that we need to/can look at when the function is
 * called are i_sb, pointing to the mounted device's super block, and i_ino,
 * the number of the inode to load.
 *
 * ntfs_read_locked_inode() maps, pins and locks the mft record number i_ino
 * for reading and sets up the necessary @vi fields 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
 *    i_flags is set to 0 and we have no business touching it.  Only an ioctl()
 *    is allowed to write to them. We should of course be honouring them but
 *    we need to do that using the IS_* macros defined in include/linux/fs.h.
 *    In any case ntfs_read_locked_inode() has nothing to do with i_flags.
 *
 * 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_inode(struct inode *vi)
{
	ntfs_volume *vol = NTFS_SB(vi->i_sb);
	ntfs_inode *ni;
	struct inode *bvi;
	MFT_RECORD *m;
	ATTR_RECORD *a;
	STANDARD_INFORMATION *si;
	ntfs_attr_search_ctx *ctx;
	int err = 0;

	ntfs_debug("Entering for i_ino 0x%lx.", vi->i_ino);

	/* Setup the generic vfs inode parts now. */

	/*
	 * This is for checking whether an inode has changed w.r.t. a file so
	 * that the file can be updated if necessary (compare with f_version).
	 */
	vi->i_version = 1;

	vi->i_uid = vol->uid;
	vi->i_gid = vol->gid;
	vi->i_mode = 0;

	/*
	 * Initialize the ntfs specific part of @vi special casing
	 * FILE_MFT which we need to do at mount time.
	 */
	if (vi->i_ino != FILE_MFT)
		ntfs_init_big_inode(vi);
	ni = NTFS_I(vi);

	m = map_mft_record(ni);
	if (IS_ERR(m)) {
		err = PTR_ERR(m);
		goto err_out;
	}
	ctx = ntfs_attr_get_search_ctx(ni, m);
	if (!ctx) {
		err = -ENOMEM;
		goto unm_err_out;
	}

	if (!(m->flags & MFT_RECORD_IN_USE)) {
		ntfs_error(vi->i_sb, "Inode is not in use!");
		goto unm_err_out;
	}
	if (m->base_mft_record) {
		ntfs_error(vi->i_sb, "Inode is an extent inode!");
		goto unm_err_out;
	}

	/* Transfer information from mft record into vfs and ntfs inodes. */
	vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);

	/*
	 * FIXME: Keep in mind that link_count is two for files which have both
	 * a long file name and a short file name as separate entries, so if
	 * we are hiding short file names this will be too high. Either we need
	 * to account for the short file names by subtracting them or we need
	 * to make sure we delete files even though i_nlink is not zero which
	 * might be tricky due to vfs interactions. Need to think about this
	 * some more when implementing the unlink command.
	 */
	vi->i_nlink = le16_to_cpu(m->link_count);
	/*
	 * FIXME: Reparse points can have the directory bit set even though
	 * they would be S_IFLNK. Need to deal with this further below when we
	 * implement reparse points / symbolic links but it will do for now.
	 * Also if not a directory, it could be something else, rather than
	 * a regular file. But again, will do for now.
	 */
	/* 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;
	if (m->flags & MFT_RECORD_IS_DIRECTORY) {
		vi->i_mode |= S_IFDIR;
		/*
		 * Apply the directory permissions mask set in the mount
		 * options.
		 */
		vi->i_mode &= ~vol->dmask;
		/* Things break without this kludge! */
		if (vi->i_nlink > 1)
			vi->i_nlink = 1;
	} else {
		vi->i_mode |= S_IFREG;
		/* Apply the file permissions mask set in the mount options. */
		vi->i_mode &= ~vol->fmask;
	}
	/*
	 * Find the standard information attribute in the mft record. At this
	 * stage we haven't setup the attribute list stuff yet, so this could
	 * in fact fail if the standard information is in an extent record, but
	 * I don't think this actually ever happens.
	 */
	err = ntfs_attr_lookup(AT_STANDARD_INFORMATION, NULL, 0, 0, 0, NULL, 0,
			ctx);
	if (unlikely(err)) {
		if (err == -ENOENT) {
			/*
			 * TODO: We should be performing a hot fix here (if the
			 * recover mount option is set) by creating a new
			 * attribute.
			 */
			ntfs_error(vi->i_sb, "$STANDARD_INFORMATION attribute "
					"is missing.");
		}
		goto unm_err_out;
	}
	a = ctx->attr;
	/* Get the standard information attribute value. */
	si = (STANDARD_INFORMATION*)((u8*)a +
			le16_to_cpu(a->data.resident.value_offset));

	/* Transfer information from the standard information into vi. */
	/*
	 * Note: The i_?times do not quite map perfectly onto the NTFS times,
	 * but they are close enough, and in the end it doesn't really matter
	 * that much...
	 */
	/*
	 * mtime is the last change of the data within the file. Not changed
	 * when only metadata is changed, e.g. a rename doesn't affect mtime.
	 */
	vi->i_mtime = ntfs2utc(si->last_data_change_time);
	/*
	 * ctime is the last change of the metadata of the file. This obviously
	 * always changes, when mtime is changed. ctime can be changed on its
	 * own, mtime is then not changed, e.g. when a file is renamed.
	 */
	vi->i_ctime = ntfs2utc(si->last_mft_change_time);
	/*
	 * Last access to the data within the file. Not changed during a rename
	 * for example but changed whenever the file is written to.
	 */
	vi->i_atime = ntfs2utc(si->last_access_time);

	/* Find the attribute list attribute if present. */
	ntfs_attr_reinit_search_ctx(ctx);
	err = ntfs_attr_lookup(AT_ATTRIBUTE_LIST, NULL, 0, 0, 0, NULL, 0, ctx);
	if (err) {
		if (unlikely(err != -ENOENT)) {
			ntfs_error(vi->i_sb, "Failed to lookup attribute list "
					"attribute.");
			goto unm_err_out;
		}
	} else /* if (!err) */ {
		if (vi->i_ino == FILE_MFT)
			goto skip_attr_list_load;
		ntfs_debug("Attribute list found in inode 0x%lx.", vi->i_ino);
		NInoSetAttrList(ni);
		a = ctx->attr;
		if (a->flags & ATTR_COMPRESSION_MASK) {
			ntfs_error(vi->i_sb, "Attribute list attribute is "
					"compressed.");
			goto unm_err_out;
		}
		if (a->flags & ATTR_IS_ENCRYPTED ||
				a->flags & ATTR_IS_SPARSE) {
			if (a->non_resident) {
				ntfs_error(vi->i_sb, "Non-resident attribute "
						"list attribute is encrypted/"
						"sparse.");
				goto unm_err_out;
			}
			ntfs_warning(vi->i_sb, "Resident attribute list "
					"attribute in inode 0x%lx is marked "
					"encrypted/sparse which is not true.  "
					"However, Windows allows this and "
					"chkdsk does not detect or correct it "
					"so we will just ignore the invalid "
					"flags and pretend they are not set.",
					vi->i_ino);
		}
		/* Now allocate memory for the attribute list. */
		ni->attr_list_size = (u32)ntfs_attr_size(a);
		ni->attr_list = ntfs_malloc_nofs(ni->attr_list_size);
		if (!ni->attr_list) {
			ntfs_error(vi->i_sb, "Not enough memory to allocate "
					"buffer for attribute list.");
			err = -ENOMEM;
			goto unm_err_out;
		}
		if (a->non_resident) {
			NInoSetAttrListNonResident(ni);
			if (a->data.non_resident.lowest_vcn) {
				ntfs_error(vi->i_sb, "Attribute list has non "
						"zero lowest_vcn.");
				goto unm_err_out;
			}
			/*
			 * Setup the runlist. No need for locking as we have
			 * exclusive access to the inode at this time.
			 */
			ni->attr_list_rl.rl = ntfs_mapping_pairs_decompress(vol,
					a, NULL);
			if (IS_ERR(ni->attr_list_rl.rl)) {
				err = PTR_ERR(ni->attr_list_rl.rl);
				ni->attr_list_rl.rl = NULL;
				ntfs_error(vi->i_sb, "Mapping pairs "
						"decompression failed.");
				goto unm_err_out;
			}
			/* Now load the attribute list. */
			if ((err = load_attribute_list(vol, &ni->attr_list_rl,
					ni->attr_list, ni->attr_list_size,
					sle64_to_cpu(a->data.non_resident.
					initialized_size)))) {
				ntfs_error(vi->i_sb, "Failed to load "
						"attribute list attribute.");
				goto unm_err_out;
			}
		} else /* if (!a->non_resident) */ {
			if ((u8*)a + le16_to_cpu(a->data.resident.value_offset)
					+ le32_to_cpu(
					a->data.resident.value_length) >
					(u8*)ctx->mrec + vol->mft_record_size) {
				ntfs_error(vi->i_sb, "Corrupt attribute list "
						"in inode.");
				goto unm_err_out;
			}
			/* Now copy the attribute list. */
			memcpy(ni->attr_list, (u8*)a + le16_to_cpu(
					a->data.resident.value_offset),
					le32_to_cpu(
					a->data.resident.value_length));
		}
	}
skip_attr_list_load:
	/*
	 * If an attribute list is present we now have the attribute list value
	 * in ntfs_ino->attr_list and it is ntfs_ino->attr_list_size bytes.
	 */
	if (S_ISDIR(vi->i_mode)) {
		loff_t bvi_size;
		ntfs_inode *bni;
		INDEX_ROOT *ir;
		u8 *ir_end, *index_end;

		/* It is a directory, find index root attribute. */
		ntfs_attr_reinit_search_ctx(ctx);
		err = ntfs_attr_lookup(AT_INDEX_ROOT, I30, 4, CASE_SENSITIVE,
				0, NULL, 0, ctx);
		if (unlikely(err)) {
			if (err == -ENOENT) {
				// FIXME: File is corrupt! Hot-fix with empty
				// index root attribute if recovery option is
				// set.
				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 index root just means that the newly
		 * created files in that directory should be created compressed/
		 * encrypted. However index root cannot be both compressed and
		 * encrypted.
		 */
		if (a->flags & ATTR_COMPRESSION_MASK)
			NInoSetCompressed(ni);
		if (a->flags & ATTR_IS_ENCRYPTED) {
			if (a->flags & ATTR_COMPRESSION_MASK) {
				ntfs_error(vi->i_sb, "Found encrypted and "
						"compressed attribute.");
				goto unm_err_out;
			}
			NInoSetEncrypted(ni);
		}