On 8/29/23 15:08, Bernd Schubert wrote:
On 8/28/23 17:05, Miklos Szeredi wrote:
On Mon, 28 Aug 2023 at 16:48, Bernd Schubert
<bernd.schubert@xxxxxxxxxxx> wrote:
On 8/28/23 13:59, Miklos Szeredi wrote:
On Thu, 24 Aug 2023 at 17:07, Bernd Schubert <bschubert@xxxxxxx> wrote:
- if (!is_sync_kiocb(iocb) && iocb->ki_flags &
IOCB_DIRECT) {
- res = fuse_direct_IO(iocb, from);
- } else {
- res = fuse_direct_io(&io, from, &iocb->ki_pos,
- FUSE_DIO_WRITE);
- fuse_write_update_attr(inode, iocb->ki_pos,
res);
While I think this is correct, I'd really like if the code to be
replaced and the replacement are at least somewhat comparable.
Sorry, I have a hard to time to understand "I'd really like if the code
to be replaced".
What I meant is that generic_file_direct_write() is not an obvious
replacement for the above lines of code.
The reason is that fuse_direct_IO() is handling the sync and async
cases in one function, while the above splits handling it based on
IOCB_DIRECT (which is now lost) and is_sync_kiocb(iocb). If it's okay
to lose IOCB_DIRECT then what's the explanation for the above
condition? It could be historic garbage, but we still need to
understand what is exactly happening.
While checking all code path again, I found an additional difference,
which I had missed before. FOPEN_DIRECT_IO will now act on
ff->fm->fc->async_dio when is is_sync_kiocb(iocb) is set.
Do you think that is a problem? If so, I could fix it in fuse_direct_IO.
What I mean is something like this
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 85f2f9d3813e..3b383dc8a944 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1635,8 +1635,10 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (FUSE_IS_DAX(inode))
return fuse_dax_write_iter(iocb, from);
- if (ff->open_flags & FOPEN_DIRECT_IO)
+ if (ff->open_flags & FOPEN_DIRECT_IO) {
iocb->ki_flags |= IOCB_DIRECT;
+ ff->iocb_direct = 1;
+ }
return fuse_cache_write_iter(iocb, from);
}
@@ -2905,6 +2907,15 @@ fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
io->iocb = iocb;
io->blocking = is_sync_kiocb(iocb);
+ /* FOPEN_DIRECT_IO historically does not use async for blocking O_DIRECT */
+ if (ff->open_flags & FOPEN_DIRECT_IO) {
+ if (!is_sync_kiocb(iocb) && ff->iocb_direct) {
+ /* no change */
+ } else {
+ io->async = 0;
+ }
+ }
+
/* optimization for short read */
if (io->async && !io->write && offset + count > i_size) {
iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset));
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index a56e83b7d29a..d77046875ad5 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -231,6 +231,9 @@ struct fuse_file {
/** Has flock been performed on this file? */
bool flock:1;
+
+ /** Has the file been opened with O_DIRECT? */
+ bool iocb_direct:1;
};
/** One input argument of a request */
Thanks,
Bernd
