[Qemu-devel] [PATCH] Substitute O_SYNC with O_FSYNC in block/raw-posix.c

[Qemu-devel] [PATCH] Substitute O_SYNC with O_FSYNC in block/raw-posix.c

[G 3]

This patch will allow the file block/raw-posix.c to compile on gcc 3.3 
on Mac OS 10.3. Since the O_SYNC symbol is missing on this version of 
the Mac OS, O_FSYNC will be used in its place.

Signed-off-by: John Arbuckle <programmingkidx@gmail.com>

---
  block/raw-posix.c |    9 +++++++++
  1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/block/raw-posix.c b/block/raw-posix.c
index fa1a394..baff82d 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -79,6 +79,15 @@
  #define DEBUG_BLOCK_PRINT(formatCstr, ...)
  #endif

+/* Mac OS less than 10.4 doesn't have O_SYNC */
+#ifndef O_SYNC
+#ifdef O_FSYNC
+#define O_SYNC O_FSYNC
+#else
+#define O_SYNC 0
+#endif
+#endif
+
  /* OS X does not have O_DSYNC */
  #ifndef O_DSYNC
  #define O_DSYNC O_SYNC
-- 
1.6.3.3

Re: [Qemu-devel] [PATCH] Substitute O_SYNC with O_FSYNC in block/raw-posix.c

[Christoph Hellwig]

On Thu, Jun 25, 2009 at 08:59:35PM -0400, G 3 wrote:
> This patch will allow the file block/raw-posix.c to compile on gcc 3.3 
> on Mac OS 10.3. Since the O_SYNC symbol is missing on this version of 
> the Mac OS, O_FSYNC will be used in its place.

Same comment about the zero as last time still applies.  Also the
look of this is really ugly as you just deinfe O_SYNC only for it
to substitute for O_DSYNC a littler later, with two comments that
together are rather confusing about macos..

[Qemu-devel] [PATCH] Substitute O_DSYNC with O_SYNC or O_FSYNC when needed.

[G 3]

On Jul 1, 2009, at 9:54 AM, Christoph Hellwig wrote:

> On Fri, Jun 26, 2009 at 03:02:47PM -0400, G 3 wrote:
>> /* OS X does not have O_DSYNC */
>> #ifndef O_DSYNC
>> #ifdef O_SYNC				/* Works on Mac OS 10.4 and
>> greater */
>> #define O_DSYNC O_SYNC
>> #elif defined(O_FSYNC)		/* Works on Mac OS 10.3 and under */
>> #define O_DSYNC O_FSYNC
>> #else						/* If no substitute is
>> available */
>> #define O_DSYNC 0			
>> #endif
>> #endif
>
> This still does the NULL sync which can cause silent data loss if no
> O_*SYNC is available.  If you want to be safe and support either O_SYNC
> or O_FSYNC as O_DSYNC replacement the following should be enough:
>
> /*
>  * MacOS X does not have O_DSYNC, and in earlier version no O_SYNC 
> either.
>  */
> #ifndef O_DSYNC
> #ifdef O_SYNC	
> #define O_DSYNC O_SYNC
> #else
> #define O_DSYNC O_FSYNC
> #endif
> #endif
>
>


This patch should be what you want.

commit b32354139556d1a807d04aa54ed82610e0f4507a
Author: John Arbuckle <programmingkidx@gmail.com>
Date:   Wed Jul 1 13:24:37 2009 -0400

     Substitute O_DSYNC with O_SYNC or O_FSYNC when needed.

     Signed-off-by: John Arbuckle <programmingkidx@gmail.com>

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 8b1e67c..17338ee 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -81,7 +81,11 @@

  /* OS X does not have O_DSYNC */
  #ifndef O_DSYNC
+#ifdef O_SYNC
  #define O_DSYNC O_SYNC
+#elif defined(O_FSYNC)
+#define O_DSYNC O_FSYNC
+#endif
  #endif

[Qemu-devel] Re: [PATCH] Substitute O_DSYNC with O_SYNC or O_FSYNC when needed.

[Christoph Hellwig]

On Wed, Jul 01, 2009 at 01:28:32PM -0400, G 3 wrote:
> This patch should be what you want.
> 
> commit b32354139556d1a807d04aa54ed82610e0f4507a
> Author: John Arbuckle <programmingkidx@gmail.com>
> Date:   Wed Jul 1 13:24:37 2009 -0400
> 
>     Substitute O_DSYNC with O_SYNC or O_FSYNC when needed.
> 
>     Signed-off-by: John Arbuckle <programmingkidx@gmail.com>

Thanks, looks good to me,


Reviewed-by: Christoph Hellwig <hch@lst.de>

> diff --git a/block/raw-posix.c b/block/raw-posix.c
> index 8b1e67c..17338ee 100644
> --- a/block/raw-posix.c
> +++ b/block/raw-posix.c
> @@ -81,7 +81,11 @@
> 
>  /* OS X does not have O_DSYNC */
>  #ifndef O_DSYNC
> +#ifdef O_SYNC
>  #define O_DSYNC O_SYNC
> +#elif defined(O_FSYNC)
> +#define O_DSYNC O_FSYNC
> +#endif
>  #endif
---end quoted text---