Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs-2.6: (21 commits)
  ext3: PTR_ERR return of wrong pointer in setup_new_group_blocks()
  ext3: Fix data / filesystem corruption when write fails to copy data
  ext4: Support for 64-bit quota format
  ext3: Support for vfsv1 quota format
  quota: Implement quota format with 64-bit space and inode limits
  quota: Move definition of QFMT_OCFS2 to linux/quota.h
  ext2: fix comment in ext2_find_entry about return values
  ext3: Unify log messages in ext3
  ext2: clear uptodate flag on super block I/O error
  ext2: Unify log messages in ext2
  ext3: make "norecovery" an alias for "noload"
  ext3: Don't update the superblock in ext3_statfs()
  ext3: journal all modifications in ext3_xattr_set_handle
  ext2: Explicitly assign values to on-disk enum of filetypes
  quota: Fix WARN_ON in lookup_one_len
  const: struct quota_format_ops
  ubifs: remove manual O_SYNC handling
  afs: remove manual O_SYNC handling
  kill wait_on_page_writeback_range
  vfs: Implement proper O_SYNC semantics
  ...

1 files changed, 21 insertions, 4 deletions

diff --git a/include/asm-generic/fcntl.h b/include/asm-generic/fcntl.h
index 495dc8af4044..681ddf3e844c 100644
--- a/include/asm-generic/fcntl.h
+++ b/include/asm-generic/fcntl.h
@@ -3,8 +3,6 @@
 
 #include <linux/types.h>
 
-/* open/fcntl - O_SYNC is only implemented on blocks devices and on files
-   located on an ext2 file system */
 #define O_ACCMODE	00000003
 #define O_RDONLY	00000000
 #define O_WRONLY	00000001
@@ -27,8 +25,8 @@
 #ifndef O_NONBLOCK
 #define O_NONBLOCK	00004000
 #endif
-#ifndef O_SYNC
-#define O_SYNC		00010000
+#ifndef O_DSYNC
+#define O_DSYNC		00010000	/* used to be O_SYNC, see below */
 #endif
 #ifndef FASYNC
 #define FASYNC		00020000	/* fcntl, for BSD compatibility */
@@ -51,6 +49,25 @@
 #ifndef O_CLOEXEC
 #define O_CLOEXEC	02000000	/* set close_on_exec */
 #endif
+
+/*
+ * Before Linux 2.6.32 only O_DSYNC semantics were implemented, but using
+ * the O_SYNC flag.  We continue to use the existing numerical value
+ * for O_DSYNC semantics now, but using the correct symbolic name for it.
+ * This new value is used to request true Posix O_SYNC semantics.  It is
+ * defined in this strange way to make sure applications compiled against
+ * new headers get at least O_DSYNC semantics on older kernels.
+ *
+ * This has the nice side-effect that we can simply test for O_DSYNC
+ * wherever we do not care if O_DSYNC or O_SYNC is used.
+ *
+ * Note: __O_SYNC must never be used directly.
+ */
+#ifndef O_SYNC
+#define __O_SYNC	04000000
+#define O_SYNC		(__O_SYNC|O_DSYNC)
+#endif
+
 #ifndef O_NDELAY
 #define O_NDELAY	O_NONBLOCK
 #endif