Re: [PATCH v4 1/5] exfat: integrates dir-entry getting and validation

Tetsuhiro Kohada
2020-08-27T14:57:27Z

Thank you for your quick review.

On 2020/08/27 12:19, Namjae Jeon wrote:
>> + i = ES_INDEX_NAME;
>> + while ((ep = exfat_get_validated_dentry(es, i++, TYPE_NAME))) {
> Please find the way to access name entries like ep_file, ep_stream
> without calling exfat_get_validated_dentry().

Hmm, it's a hard order.
I can't separate length/type validation and extraction.
Sorry, I have no good idea.

>> @@ -590,17 +587,16 @@ int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir, void
>> exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es) {
>> int chksum_type = CS_DIR_ENTRY, i;
>> - unsigned short chksum = 0;
>> + u16 chksum = 0;
>> struct exfat_dentry *ep;
>>
>> for (i = 0; i < es->num_entries; i++) {
>> - ep = exfat_get_dentry_cached(es, i);
>> + ep = exfat_get_validated_dentry(es, i, TYPE_ALL);
> Ditto, You do not need to repeatedly call exfat_get_validated_dentry() for the entries
> which got from exfat_get_dentry_set().

Even if I could do that, it would be very difficult to implement a checksum patch.
It is also difficult to use for rename, move, delete.
(these also have no verification of neme-length and set-checksum)

>> /* validiate cached dentries */
>> - for (i = 1; i < num_entries; i++) {
>> - ep = exfat_get_dentry_cached(es, i);
>> - if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
>> - goto free_es;
>> + es->ep_stream = exfat_get_validated_dentry(es, ES_INDEX_STREAM, TYPE_STREAM);
>> + if (!es->ep_stream)
>> + goto free_es;
>> +
>> + if (max_entries == ES_ALL_ENTRIES) {
>> + for (i = 0; i < ES_FILE(es).num_ext; i++)
>> + if (!exfat_get_validated_dentry(es, ES_INDEX_STREAM + i, TYPE_SECONDARY))
>> + goto free_es;
>> + for (i = 0; i * EXFAT_FILE_NAME_LEN < ES_STREAM(es).name_len; i++)
>> + if (!exfat_get_validated_dentry(es, ES_INDEX_NAME + i, TYPE_NAME))
>> + goto free_es;
> Why do you unnecessarily check entries with two loops?
> Please refer to the patch I sent.

This order is possible.
However, TYPE_SECONDARY loop will be back as checksum loop.

In the next patch, I can fix the 'TYPE_SECONDARY loop' order.
do you need it?

BR
---
Tetsuhiro Kohada <kohada.t2@gmail.com>