On Thu, Jul 25, 2013 at 12:13 AM, Zheng Liu <gnehzuil.liu@xxxxxxxxx> wrote: > On Wed, Jul 24, 2013 at 09:58:45PM +0000, jon ernst wrote: >> > My purpose is to trigger this bug and fix it. So I manually define this >> > flag for my convenience. >> > >> >> I saw it has >> >> been defined in header file. (fcntl.h) Did I miss anything? >> > >> > I guess that you might 'include <fcntl.h>' header file, right? But the >> > O_TMPFILE is defined in $LINUX/include/uapi/asm-generic/fcntl.h. So >> > maybe compiler couldn't find this header file. >> > >> > Regards, >> > - Zheng >> -- >> Got it. Thank you. BTW, the weird thing is I didn't see any >> discussion on ext4 mailing list before Al Viro committed this change. >> The first time I heard about this is someone reporting a bug about it. >> Document about this FLAG might be necessary. > > Oh, this flag has been discussed in linux-fsdevel mailing list [1]. > Maybe you don't subscribe it. > > 1. https://lkml.org/lkml/2013/7/3/181 > >> Also, about this code: >> >> /* a horrid kludge trying to make sure that this will fail on old kernels */ >> #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) >> >> why not doing something like this: >> >> #ifndef O_TMPFILE >> /* a horrid kludge trying to make sure that this will fail on old kernels */ >> #define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) >> #endif > > Sorry, I don't take a closer look at that thread. I look at the code, > and it seems that there is no any rule about adding '#ifndef XXX'. > Meanwhile, I notice a comment: > > /* > * When introducing new O_* bits, please check its uniqueness in fcntl_init(). > */ > > But we are missing adding O_TMPFILE flag in fcntl_init(). So I attach a > patch below. > Great. I think this is the reason O_TMPFILE is unrecognizable in user space. As the problem I reported 2 days ago in the thread that you fixed another bug. > Al, could you please answer this question? Thanks. > > Regards, > - Zheng > > Subject: [PATCH] vfs: add missing check for __O_TMPFILE in fcntl_init() > > From: Zheng Liu <wenqing.lz@xxxxxxxxxx> > > As comment in include/uapi/asm-generic/fcntl.h described, when > introducing new O_* bits, we need to check its uniqueness in > fcntl_init(). But __O_TMPFILE bit is missing. So fix it. > > Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx> > --- > *This patch is against ext4/dev tree.* > > fs/fcntl.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/fcntl.c b/fs/fcntl.c > index 6599222..65343c3 100644 > --- a/fs/fcntl.c > +++ b/fs/fcntl.c > @@ -730,14 +730,14 @@ static int __init fcntl_init(void) > * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY > * is defined as O_NONBLOCK on some platforms and not on others. > */ > - BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( > + BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( > O_RDONLY | O_WRONLY | O_RDWR | > O_CREAT | O_EXCL | O_NOCTTY | > O_TRUNC | O_APPEND | /* O_NONBLOCK | */ > __O_SYNC | O_DSYNC | FASYNC | > O_DIRECT | O_LARGEFILE | O_DIRECTORY | > O_NOFOLLOW | O_NOATIME | O_CLOEXEC | > - __FMODE_EXEC | O_PATH > + __FMODE_EXEC | O_PATH | __O_TMPFILE > )); > > fasync_cache = kmem_cache_create("fasync_cache", > -- > 1.7.9.7 > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
