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@xxxxxxxxxx>
---
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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