arnavsharma990 opened a new issue, #20037:
URL: https://github.com/apache/nuttx/issues/20037

   ### Description
   
   Hi NuttX community,
   
   I'm looking into the TODO in `fs/fat/fs_fat32.c` regarding 
`rmdir()`/`unlink()` behavior when a file or directory is still open:
   
   > "Need to defer deleting cluster chain if the file is open."
   
   I've been investigating the current FAT implementation and prototyped a 
small fix using a `pending-delete` state on `struct fat_file_s` and the 
existing `fs_head` open-file list.
   
   However, I ran into an identity/lifetime question.
   
   Using `ff_startcluster` to determine whether an open handle belongs to the 
unlinked file does not seem safe because:
   - an empty file has `ff_startcluster == 0` and can acquire a cluster later 
when written;
   - cluster numbers can be reused;
   - `ff_dirsector` / `ff_dirindex` represent the directory entry location, but 
directory entries can be moved by rename and reused after unlink;
   - `fat_dup()` currently creates another `fat_file_s` rather than sharing a 
canonical underlying file object.
   
   So I'm wondering what the intended design is here.
   
   Would the preferred approach be to introduce some small FAT-local per-file 
identity/lifetime state (for example, a canonical `fat_file_s` with a reference 
count and pending-delete state), or is there an existing FAT/VFS mechanism that 
should be used for associating open handles with the underlying file across 
unlink/rename?
   
   I would appreciate any guidance on the intended approach before I open a PR.
   
   Thanks!
   
   ### Verification
   
   - [x] I have verified before submitting the report.


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