[PATCH v3 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.

---

Changes in v3:
- rework exfat_chain_advance
- add error handling in exfat_find_location
- misc tweaks

v1:https://lore.kernel.org/linux-fsdevel/20260331091113.20882-1-chizhiling@163.com/
v2:https://lore.kernel.org/linux-fsdevel/20260401071138.114836-1-chizhiling@163.com/


Chi Zhiling (6):
  exfat: fix incorrect directory checksum after rename to shorter name
  exfat: introduce exfat_cluster_walk helper
  exfat: use exfat_cluster_walk helper
  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      | 119 +++++++++++---------------------------------
 fs/exfat/exfat_fs.h |  44 +++++++++++++++-
 fs/exfat/fatent.c   |  23 ++++-----
 fs/exfat/inode.c    |  11 +---
 fs/exfat/namei.c    |  28 +++--------
 5 files changed, 91 insertions(+), 134 deletions(-)


base-commit: 4129a3a2751cba8511cee5d13145223662a8e019
-- 
2.43.0