[PATCH v1 0/6] exfat: unify FAT chain walking helpers

[Chi Zhiling <chizhiling@163.com>]

From: Chi Zhiling <chizhiling@kylinos.cn>

This series introduces and uses two new helpers to simplify FAT chain
walking logic across the exfat driver:

1. exfat_fat_walk - walks FAT chain by a given step, handling both
   ALLOC_NO_FAT_CHAIN and ALLOC_FAT_CHAIN modes

2. exfat_chain_advance - walks an exfat_chain structure by a given step,
   updating both ->dir and ->size fields atomically with proper boundary
   checking

These helpers replace open-coded cluster walking logic in dir.c, namei.c
and inode.c, improving code readability and ensuring consistent error
handling for corrupted FAT chains.

Also includes a fix for incorrect directory checksum when renaming a
file to a shorter name.

The base commit is exfat/dev without iomap changes


Chi Zhiling (6):
  exfat: fix incorrect directory checksum after rename to shorter name
  exfat: introduce exfat_fat_walk helper
  exfat: use exfat_fat_walk helper to simplify fat entry walking
  exfat: remove NULL cache pointer case in exfat_ent_get
  exfat: introduce exfat_chain_advance helper
  exfat: use exfat_chain_advance helper

 fs/exfat/dir.c      | 111 +++++++++-----------------------------------
 fs/exfat/exfat_fs.h |  49 ++++++++++++++++++-
 fs/exfat/fatent.c   |  23 ++++-----
 fs/exfat/inode.c    |  11 +----
 fs/exfat/namei.c    |  29 +++---------
 5 files changed, 88 insertions(+), 135 deletions(-)

-- 
2.43.0