alt Hacker NewsI don't know how Linux driver updates FAT, but if it doesn't do it the way DOS did, then it's a bug that puts data at risk.
1) Allocate space in FAT#2, 2) Write data in file, 3) Allocate space in FAT#1, 4) Update directory entry (file size), 5) Update free space count.
Rename in FAT is an atomic operation. Overwrite old name with new name in the directory entry, which is just 1 sector write (or 2 if it has a long file name too).
No, the VFAT driver doesn't do anything even slightly resembling that.
In general "what DOS did" doesn't cut for a modern system with page and dentry caches and multiple tasks accessing the filesystem without completely horrible performance. I would be really surprised if Windows handled all those cases right with disk caching enabled.
While rename can be atomic in some cases, it cannot be in the case of cross directory renames or when the new filename doesn't fit in the existing directory sector.