Messages in this thread Patch in this message | | | Date | Fri, 21 Nov 2014 21:15:53 +0100 | From | Heinrich Schuchardt <> | Subject | Re: [PATCH] vfs: renumber FMODE_NONOTIFY and add to uniqueness check |
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On 21.11.2014 10:41, David Drysdale wrote: > Although FMODE_NONOTIFY is only used internally in the kernel it is in > the same numbering space as the other O_* flags, as indicated by the > comment at the top of include/uapi/asm-generic/fcntl.h (and its use > in fs/notify/fanotify/fanotify_user.c). However, its current value > clashes with the value of O_PATH on sparc, so renumber it to avoid > the clash. > > All of this has happened before (12ed2e36c98aec6c4155, "fanotify: > FMODE_NONOTIFY and __O_SYNC in sparc conflict"),
vfs: add nonconflicting values for O_PATH 5229645bdc35f1cc43eb8b25b6993c8fa58b4b43 unfortunately introduced a new conflict.
> and all of this > will happen again -- so update the uniqueness check in fcntl_init() > to include __FMODE_NONOTIFY.
> > Signed-off-by: David Drysdale <drysdale@google.com> > --- > fs/fcntl.c | 5 +++-- > include/linux/fs.h | 4 ++-- > include/uapi/asm-generic/fcntl.h | 2 +- > 3 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/fs/fcntl.c b/fs/fcntl.c > index 99d440a4a6ba..ee85cd4e136a 100644 > --- a/fs/fcntl.c > +++ b/fs/fcntl.c > @@ -740,14 +740,15 @@ 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(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( > + BUILD_BUG_ON(21 - 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 | __O_TMPFILE > + __FMODE_EXEC | O_PATH | __O_TMPFILE | > + __FMODE_NONOTIFY > )); > > fasync_cache = kmem_cache_create("fasync_cache", > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 9ab779e8a63c..fd8611d423a0 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -80,7 +80,7 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset, > > /* > * flags in file.f_mode. Note that FMODE_READ and FMODE_WRITE must correspond > - * to O_WRONLY and O_RDWR via the strange trick in __dentry_open() > + * to O_WRONLY and O_RDWR via the strange trick in OPEN_FMODE() below.
Please, put this change into a separate patch. It seems unrelated to the definition of __FMODE_NONOTIFY.
> */ > > /* file is open for reading */ > @@ -134,7 +134,7 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset, > #define FMODE_CAN_WRITE ((__force fmode_t)0x40000) > > /* File was opened by fanotify and shouldn't generate fanotify events */ > -#define FMODE_NONOTIFY ((__force fmode_t)0x1000000) > +#define FMODE_NONOTIFY ((__force fmode_t)0x4000000)
The cause of the pain is arch/sparc/include/uapi/asm/fcntl.h:37: #define O_PATH 0x1000000 We cannot change that definition due to the need for backwards compatibility.
> > /* > * Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector > diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h > index 7543b3e51331..e063effe0cc1 100644 > --- a/include/uapi/asm-generic/fcntl.h > +++ b/include/uapi/asm-generic/fcntl.h > @@ -5,7 +5,7 @@ > > /* > * FMODE_EXEC is 0x20 > - * FMODE_NONOTIFY is 0x1000000 > + * FMODE_NONOTIFY is 0x4000000 > * These cannot be used by userspace O_* until internal and external open > * flags are split. > * -Eric Paris >
The patch is applicable to 3.18.0-rc4.
I CC Jan as he has done a lot of the recent file notification development.
Best regards
Heinrich Schuchardt
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