Re: [PATCH v2 0/7] exfat: fix valid_size update races

[Chi Zhiling]

On 10/13/2026 12:04 PM, Namjae Jeon wrote:
> On Tue, Oct 13, 2026 at 12:39 PM Chi Zhiling <chizhiling@xxxxxxx> wrote:
> > From: Chi Zhiling <chizhiling@xxxxxxxxxx>
> Hi Chi,

Hi Namjae,

> > exFAT uses valid_size (ValidDataLength) as the on-disk boundary of
> > initialised data, but the current code advances it too late or without
> > proper serialisation.  As a result, buffered writes can silently lose
> > data reclaimed before valid_size covers it, page faults and direct I/O
> > can race with writes, and a failed direct write still grows the file
> > on disk.
> >
> > This series advances valid_size under the folio lock for buffered
> > writes, revalidates cached iomaps, drops i_rwsem from
> > exfat_page_mkwrite(), and publishes i_size/valid_size only on
> > successful direct I/O completion.
> >
> > V1: https://lore.kernel.org/exfat/59056131-e3bd-4003-8c30-0a356cf0bd82@xxxxxxx/
> > Link: https://lore.kernel.org/exfat/10029d6f-13cc-4d17-a2f9-b093a8339dde/T/#t
> >
> > Chi Zhiling (7):
> >    exfat: advance valid_size under the folio lock for buffered writes
> >    exfat: advance valid_size while zeroing new ranges
> >    exfat: validate cached iomaps during buffered writes
> >    exfat: drop i_rwsem from exfat_page_mkwrite
> >    exfat: do not re-zero the valid range in exfat_page_mkwrite
> >    exfat: complete direct writes synchronously when they update metadata
> >    exfat: publish i_size and valid_size on direct I/O completion
> Can you add fixes tags to the patches ?

Sure, I'll add Fixes tag in the next version.