vfs: separate FMODE_PREAD/FMODE_PWRITE into separate flags
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>
Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6022f44..5852bd6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -54,24 +54,30 @@
#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)
/*
* Don't update ctime and mtime.