On Fri, Oct 25, 2024 at 04:03:02PM +0530, Ritesh Harjani wrote:
> John Garry <john.g.garry@xxxxxxxxxx> writes:
>
> > On 25/10/2024 04:45, Ritesh Harjani (IBM) wrote:
> >> Let's validate using generic_atomic_write_valid() in
> >> ext4_file_write_iter() if the write request has IOCB_ATOMIC set.
> >>
> >> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
> >> ---
> >> fs/ext4/file.c | 14 ++++++++++++++
> >> 1 file changed, 14 insertions(+)
> >>
> >> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> >> index f14aed14b9cf..b06c5d34bbd2 100644
> >> --- a/fs/ext4/file.c
> >> +++ b/fs/ext4/file.c
> >> @@ -692,6 +692,20 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
> >> if (IS_DAX(inode))
> >> return ext4_dax_write_iter(iocb, from);
> >> #endif
> >> +
> >> + if (iocb->ki_flags & IOCB_ATOMIC) {
> >> + size_t len = iov_iter_count(from);
> >> + int ret;
> >> +
> >> + if (!IS_ALIGNED(len, EXT4_SB(inode->i_sb)->fs_awu_min) ||
> >> + len > EXT4_SB(inode->i_sb)->fs_awu_max)
> >> + return -EINVAL;
> >
> > this looks ok, but the IS_ALIGNED() check looks odd. I am not sure why
> > you don't just check that fs_awu_max >= len >= fs_awu_min
> >
>
> I guess this was just a stricter check. But we anyways have power_of_2
> and other checks in generic_atomic_write_valid(). So it does not matter.
>
> I can change this in v2.
Also please fix the weird indenting in the if test:
if (len < EXT4_SB(inode->i_sb)->fs_awu_min) ||
len > EXT4_SB(inode->i_sb)->fs_awu_max)
return -EINVAL;
--D
> Thanks!
>
> >> +
> >> + ret = generic_atomic_write_valid(iocb, from);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> +
> >> if (iocb->ki_flags & IOCB_DIRECT)
> >> return ext4_dio_write_iter(iocb, from);
> >> else
>
> -ritesh
>
