[patch 005/114] vfs: separate FMODE_PREAD/FMODE_PWRITE into separate flags

Greg KH
2009-03-14T01:22:05Z

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2.6.28-stable review patch. If anyone has any objections, please let us know.

------------------

From: Paul Turner <pjt@google.com>

commit 55ec82176eca52e4e0530a82a0eb59160a1a95a1 upstream.

Separate FMODE_PREAD and FMODE_PWRITE into separate flags to reflect the
reality that the read and write paths may have independent restrictions.

A git grep verifies that these flags are always cleared together so this
new behavior will only apply to interfaces that change to clear flags
individually.

This is required for "seq_file: properly cope with pread", a post-2.6.25
regression fix.

[akpm@linux-foundation.org: add comment]
Signed-off-by: Paul Turner <pjt@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
include/linux/fs.h | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)

--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -63,24 +63,30 @@ extern int dir_notify_enable;
#define MAY_ACCESS 16
#define MAY_OPEN 32

+/*
+ * 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()
+ */
+
/* file is open for reading */
#define FMODE_READ ((__force fmode_t)1)
/* file is open for writing */
#define FMODE_WRITE ((__force fmode_t)2)
/* file is seekable */
#define FMODE_LSEEK ((__force fmode_t)4)
-/* file can be accessed using pread/pwrite */
+/* file can be accessed using pread */
#define FMODE_PREAD ((__force fmode_t)8)
-#define FMODE_PWRITE FMODE_PREAD /* These go hand in hand */
+/* file can be accessed using pwrite */
+#define FMODE_PWRITE ((__force fmode_t)16)
/* File is opened for execution with sys_execve / sys_uselib */
-#define FMODE_EXEC ((__force fmode_t)16)
+#define FMODE_EXEC ((__force fmode_t)32)
/* File is opened with O_NDELAY (only set for block devices) */
-#define FMODE_NDELAY ((__force fmode_t)32)
+#define FMODE_NDELAY ((__force fmode_t)64)
/* File is opened with O_EXCL (only set for block devices) */
-#define FMODE_EXCL ((__force fmode_t)64)
+#define FMODE_EXCL ((__force fmode_t)128)
/* File is opened using open(.., 3, ..) and is writeable only for ioctls
(specialy hack for floppy.c) */
-#define FMODE_WRITE_IOCTL ((__force fmode_t)128)
+#define FMODE_WRITE_IOCTL ((__force fmode_t)256)

#define RW_MASK 1
#define RWA_MASK 2