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

[Tetsuhiro Kohada]

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 

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

[Namjae Jeon]

> + 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().
>   exfat_extract_uni_name(ep, uniname);
>   uniname += EXFAT_FILE_NAME_LEN;
>   }
> @@ -372,7 +369,7 @@ unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
>   if (ep->type == EXFAT_STREAM)
>   return TYPE_STREAM;
>   if (ep->type == EXFAT_NAME)
> - return TYPE_EXTEND;
> + return TYPE_NAME;
>   if (ep->type == EXFAT_ACL)
>   return TYPE_ACL;
>   return TYPE_CRITICAL_SEC;
> @@ -388,7 +385,7 @@ static void exfat_set_entry_type(struct exfat_dentry *ep, 
> unsigned int type)
>   ep->type &= EXFAT_DELETE;
>   } else if (type == TYPE_STREAM) {
>   ep->type = EXFAT_STREAM;
> - } else if (type == TYPE_EXTEND) {
> + } else if (type == TYPE_NAME) {
>   ep->type = EXFAT_NAME;
>   } else if (type == TYPE_BITMAP) {
>   ep->type = EXFAT_BITMAP;
> @@ -421,7 +418,7 @@ static void exfat_init_name_entry(struct exfat_dentry 
> *ep,  {
>   int i;
> 
> - exfat_set_entry_type(ep, TYPE_EXTEND);
> + exfat_set_entry_type(ep, TYPE_NAME);
>   ep->dentry.name.flags = 0x0;
> 
>   for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) { @@ -550,7 +547,7 @@ int 
> exfat_init_ext_entry(struct
> inode *inode, struct exfat_chain *p_dir,
>   exfat_update_bh(bh, sync);
>   brelse(bh);
> 
> - for (i = EXFAT_FIRST_CLUSTER; i < num_entries; i++) {
> + for (i = ES_INDEX_NAME; i < num_entries; i++) {
>   ep = exfat_get_dentry(sb, p_dir, entry + i, &bh, §or);
>   if (!ep)
>   return -EIO;
> @@ -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().
>   chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
>chksum_type);
>   chksum_type = CS_DEFAULT;
>   }
> - ep = exfat_get_dentry_cached(es, 0);
> - ep->dentry.file.checksum = cpu_to_le16(chksum);
> + ES_FILE(es).checksum = cpu_to_le16(chksum);
>   es->modified = true;
>  }
> 
>  struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
> - struct exfat_chain *p_dir, int entry, unsigned int type)
> + struct exfat_chain *p_dir, int entry, int max_entries)
>  {
>   int ret, i, num_bh;
> - unsigned int off, byte_offset, clu = 0;
> + unsigned int byte_offset, clu = 0;
>   sector_t sec;
>   struct exfat_sb_info *sbi = EXFAT_SB(sb);
>   struct exfat_entry_set_cache *es;
> - struct exfat_dentry *ep;
> - int num_entries;
> - enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
>   struct buffer_head *bh;
> 
>   if (p_dir->dir == DIR_DELETED) {
> @@ -844,13 +811,13 @@ struct exfat_entry_set_cache 
> *exfat_get_dentry_set(struct super_block *sb,
>   return NULL;
>   es->sb = sb;
>   es->modified = false;
> + es->num_entries = 1;
> 
>   /* byte offset in cluster */
>   byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
> 
>   /* byte offset in sector */
> - off = EXFAT_BLK_OFFSET(byte_offset, sb);
> - es->start_off = off;
> + es->start_off = EXFAT_BLK_OFFSET(byte_offset, sb);
> 
>   /* sector offset in cluster */
>   sec = EXFAT_B_TO_BLK(byte_offset, sb); @@ -861,15 +828,12 @@ struct 
> exfat_entry_set_cache
> *exfat_get_dentry_set(struct super_block *sb,
>   goto free_es;
>   es->bh[es->num_bh++] = bh;
> 
> - ep = exfat_get_dentry_cached(es, 0);
> - if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
> + es->ep_file = exfat_get_validated_dentry(es, ES_INDEX_FILE, TYPE_FILE);
> + if (!es->ep_file)
>   goto free_es;
> + es->num_entries = min(ES_FILE(es).num_ext + 1, max_entries);
> 
> - num_entries = type == ES_ALL_ENTRIES ?
> - ep->dentry.file.num_ext + 1 : type;
> - es->num_entries = num_entries;
> -
> - num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
> + num_bh = EXFAT_B_TO_BLK_ROUND_UP(es->start_off  + es->num_entries *
> +DENTRY_SIZE, sb);
>   for (i = 1; i < num_bh; i++) {
>   /* get the next sector */
>