Re: finderInfo of the Spotlight directory files.

[Vyacheslav Dubeyko <slava@dubeyko.com>]

Hi Hin-Tak,

On Mon, 2014-04-14 at 11:08 +0100, Hin-Tak Leung wrote:
> Those files returns 'no such attribute' when doing getfattr -m ''.
> Their user_info and finder_info are entirely nulls. But that's quite
> expected since those files are not user created and not accessible by
> finder. So they should simply be quiet, rather than resulting in 'no
> such attribute' error. 
> 

My logic was simple. If we haven't xattrs in AttributesFile and
user_info and finder_info are entirely nulls (nothing show to user) then
it means that we haven't xattrs completely. It is one of the possible
point of view.

>From another point of view, we can think that we have
"com.apple.FinderInfo" xattr always. And we can show array of zero for
the case of empty user_info and finder_info areas. It is possible to
simplify hfsplus_listxattr_finder_info() method:


static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
                                                char *buffer, size_t size)
{
        ssize_t res = 0;
        struct inode *inode = dentry->d_inode;
        struct hfs_find_data fd;
        u16 entry_type;
        int xattr_name_len, symbols_count;

        res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->cat_tree, &fd);
        if (res) {
                pr_err("can't init xattr find struct\n");
                return res;
        }

        res = hfsplus_find_cat(inode->i_sb, inode->i_ino, &fd);
        if (res)
                goto end_listxattr_finder_info;

        entry_type = hfs_bnode_read_u16(fd.bnode, fd.entryoffset);
        if (entry_type != HFSPLUS_FOLDER && entry_type != HFSPLUS_FILE) {
                res = -EOPNOTSUPP;
                goto end_listxattr_finder_info;
        }

        symbols_count = sizeof(HFSPLUS_XATTR_FINDER_INFO_NAME) - 1;
        xattr_name_len =
            name_len(HFSPLUS_XATTR_FINDER_INFO_NAME, symbols_count);
        if (!buffer || !size) {
                if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME))
                        res = xattr_name_len;
        } else if (can_list(HFSPLUS_XATTR_FINDER_INFO_NAME)) {
                if (size < xattr_name_len)
                        res = -ERANGE;
                else {
                        res = copy_name(buffer,
                                        HFSPLUS_XATTR_FINDER_INFO_NAME,
                                        symbols_count);
                }
        }

end_listxattr_finder_info:
        hfs_find_exit(&fd);

        return res;
}

> In fact there seems to be another related issue: linux created files
> under hfs+ have their finderinfo ( creater and file type, etc) filled
> with garbage. I think there were a bug report a while back about the
> finder flags (also part of finderinfo) being filled with gabbage, but
> those were corrected. 
> 

I think that this method is not the point of deep check of file system
consistency. This method is checking entry type. I think that such check
is enough here. The hfsplus_find_cat() makes some checking consistency
of b-tree nodes. And if we will have real garbage then trying to find
catalog record fails. I don't think that it needs to make consistency
checking stricter here.

Thanks,
Vyacheslav Dubeyko.