| Message ID | 20230806-resolve_cached-o_tmpfile-v2-2-058bff24fb16@cyphar.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | open: make RESOLVE_CACHED correctly test for O_TMPFILE | expand |
On 8/5/23 4:48?PM, Aleksa Sarai wrote: > O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old > check for whether RESOLVE_CACHED can be used would incorrectly think > that O_DIRECTORY could not be used with RESOLVE_CACHED. > > Cc: stable@vger.kernel.org # v5.12+ > Fixes: 3a81fd02045c ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups") > Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> > --- > io_uring/openclose.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/io_uring/openclose.c b/io_uring/openclose.c > index 10ca57f5bd24..a029c230119f 100644 > --- a/io_uring/openclose.c > +++ b/io_uring/openclose.c > @@ -35,9 +35,9 @@ static bool io_openat_force_async(struct io_open *open) > { > /* > * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, > - * it'll always -EAGAIN > + * it'll always -EAGAIN. Please don't make this change, it just detracts from the actual change. And if we are making changes in there, why not change O_TMPFILE as well since this is what the change is about?
On 2023-08-05, Jens Axboe <axboe@kernel.dk> wrote: > On 8/5/23 4:48?PM, Aleksa Sarai wrote: > > O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old > > check for whether RESOLVE_CACHED can be used would incorrectly think > > that O_DIRECTORY could not be used with RESOLVE_CACHED. > > > > Cc: stable@vger.kernel.org # v5.12+ > > Fixes: 3a81fd02045c ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups") > > Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> > > --- > > io_uring/openclose.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/io_uring/openclose.c b/io_uring/openclose.c > > index 10ca57f5bd24..a029c230119f 100644 > > --- a/io_uring/openclose.c > > +++ b/io_uring/openclose.c > > @@ -35,9 +35,9 @@ static bool io_openat_force_async(struct io_open *open) > > { > > /* > > * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, > > - * it'll always -EAGAIN > > + * it'll always -EAGAIN. > > Please don't make this change, it just detracts from the actual change. > And if we are making changes in there, why not change O_TMPFILE as well > since this is what the change is about? Userspace can't pass just __O_TMPFILE, so to me "__O_TMPFILE open" sounds strange. The intention is to detect open(O_TMPFILE), it just so happens that the correct check is __O_TMPFILE. But I can change it if you prefer.
On 8/6/23 12:42?AM, Aleksa Sarai wrote: > On 2023-08-05, Jens Axboe <axboe@kernel.dk> wrote: >> On 8/5/23 4:48?PM, Aleksa Sarai wrote: >>> O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old >>> check for whether RESOLVE_CACHED can be used would incorrectly think >>> that O_DIRECTORY could not be used with RESOLVE_CACHED. >>> >>> Cc: stable@vger.kernel.org # v5.12+ >>> Fixes: 3a81fd02045c ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups") >>> Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> >>> --- >>> io_uring/openclose.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/io_uring/openclose.c b/io_uring/openclose.c >>> index 10ca57f5bd24..a029c230119f 100644 >>> --- a/io_uring/openclose.c >>> +++ b/io_uring/openclose.c >>> @@ -35,9 +35,9 @@ static bool io_openat_force_async(struct io_open *open) >>> { >>> /* >>> * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, >>> - * it'll always -EAGAIN >>> + * it'll always -EAGAIN. >> >> Please don't make this change, it just detracts from the actual change. >> And if we are making changes in there, why not change O_TMPFILE as well >> since this is what the change is about? > > Userspace can't pass just __O_TMPFILE, so to me "__O_TMPFILE open" > sounds strange. The intention is to detect open(O_TMPFILE), it just so > happens that the correct check is __O_TMPFILE. Right, but it's confusing now as the comment refers to O_TMPFILE but __O_TMPFILE is being used. I'd include a comment in there on why it's __O_TMPFILE and not O_TMPFILE, that's the interesting bit. As it stands, you'd read the comment and look at the code and need to figure that on your own. Hence it deserves a comment.
diff --git a/io_uring/openclose.c b/io_uring/openclose.c index 10ca57f5bd24..a029c230119f 100644 --- a/io_uring/openclose.c +++ b/io_uring/openclose.c @@ -35,9 +35,9 @@ static bool io_openat_force_async(struct io_open *open) { /* * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, - * it'll always -EAGAIN + * it'll always -EAGAIN. */ - return open->how.flags & (O_TRUNC | O_CREAT | O_TMPFILE); + return open->how.flags & (O_TRUNC | O_CREAT | __O_TMPFILE); } static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
O_TMPFILE is actually __O_TMPFILE|O_DIRECTORY. This means that the old check for whether RESOLVE_CACHED can be used would incorrectly think that O_DIRECTORY could not be used with RESOLVE_CACHED. Cc: stable@vger.kernel.org # v5.12+ Fixes: 3a81fd02045c ("io_uring: enable LOOKUP_CACHED path resolution for filename lookups") Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> --- io_uring/openclose.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)