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

From: Namjae Jeon
Date: Wed Aug 26 2020 - 23:19:44 EST

> + 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, &sector);
> 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 */
> if (exfat_is_last_sector_in_cluster(sbi, sec)) { @@ -889,10 +853,17 @@ struct
> exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
> }
>
> /* 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.

> }
> return es;

>
> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index 44dc04520175..e46f3e0c16b7 100644
> --- a/fs/exfat/exfat_fs.h
> +++ b/fs/exfat/exfat_fs.h
> @@ -40,7 +40,7 @@ enum {
> * Type Definitions
> */
> #define ES_2_ENTRIES 2
> -#define ES_ALL_ENTRIES 0
> +#define ES_ALL_ENTRIES 256
>
> #define DIR_DELETED 0xFFFF0321
>
> @@ -56,7 +56,7 @@ enum {
> #define TYPE_FILE 0x011F
> #define TYPE_CRITICAL_SEC 0x0200
> #define TYPE_STREAM 0x0201
> -#define TYPE_EXTEND 0x0202
> +#define TYPE_NAME 0x0202
> #define TYPE_ACL 0x0203
> #define TYPE_BENIGN_PRI 0x0400
> #define TYPE_GUID 0x0401
> @@ -65,6 +65,9 @@ enum {
> #define TYPE_BENIGN_SEC 0x0800
> #define TYPE_ALL 0x0FFF
>
> +#define TYPE_PRIMARY (TYPE_CRITICAL_PRI | TYPE_BENIGN_PRI)
Where is this in use? If it is not used, Do not need to add it.
> +#define TYPE_SECONDARY (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)
> +
> #define MAX_CHARSET_SIZE 6 /* max size of multi-byte character */
> #define MAX_NAME_LENGTH 255 /* max len of file name excluding NULL */
> #define MAX_VFSNAME_BUF_SIZE ((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)