[PATCH] fallocate: avoid preprocessor token redefinitions

[PATCH] fallocate: avoid preprocessor token redefinitions

[Sami Kerola]

The FALLOC_FL_KEEP_SIZE and FALLOC_FL_PUNCH_HOLE are part of
bits/fcntl-linux.h, and one should prefer use of libc rather than
kernel header linux/falloc.h when possible.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
---
 sys-utils/fallocate.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/sys-utils/fallocate.c b/sys-utils/fallocate.c
index 6a87673..9fa1e58 100644
--- a/sys-utils/fallocate.c
+++ b/sys-utils/fallocate.c
@@ -36,8 +36,10 @@
 # include <sys/syscall.h>
 #endif
 
-#ifdef HAVE_LINUX_FALLOC_H
-# include <linux/falloc.h>	/* for FALLOC_FL_* flags */
+#ifndef HAVE_LINUX_FALLOC_H
+# ifndef FALLOC_FL_KEEP_SIZE	/* FALLOC_FL_* should be part of */
+#  include <linux/falloc.h>	/* bits/fcntl-linux.h that is */
+# endif				/* included by fcntl.h */
 #endif
 
 #ifndef FALLOC_FL_KEEP_SIZE
-- 
1.8.5.2

Re: [PATCH] fallocate: avoid preprocessor token redefinitions

[Karel Zak]

On Tue, Jan 07, 2014 at 10:04:59PM +0000, Sami Kerola wrote:
> The FALLOC_FL_KEEP_SIZE and FALLOC_FL_PUNCH_HOLE are part of
> bits/fcntl-linux.h, and one should prefer use of libc rather than
> kernel header linux/falloc.h when possible.
> 
> Signed-off-by: Sami Kerola <kerolasa@iki.fi>
> ---
>  sys-utils/fallocate.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/sys-utils/fallocate.c b/sys-utils/fallocate.c
> index 6a87673..9fa1e58 100644
> --- a/sys-utils/fallocate.c
> +++ b/sys-utils/fallocate.c
> @@ -36,8 +36,10 @@
>  # include <sys/syscall.h>
>  #endif
>  
> -#ifdef HAVE_LINUX_FALLOC_H
> -# include <linux/falloc.h>	/* for FALLOC_FL_* flags */
> +#ifndef HAVE_LINUX_FALLOC_H
    ^^^^^
> +# ifndef FALLOC_FL_KEEP_SIZE	/* FALLOC_FL_* should be part of */
> +#  include <linux/falloc.h>	/* bits/fcntl-linux.h that is */
> +# endif				/* included by fcntl.h */
>  #endif

Maybe I read the patch incorrectly, but you're trying to include
<linux/falloc.h> when HAVE_LINUX_FALLOC_H is undefined :-)

I have applied the patch below.

    Karel

commit bc5ddf0c0011d1ffc21e29cef9d07420013697b0
Author: Karel Zak <kzak@redhat.com>
Date:   Mon Jan 13 14:53:18 2014 +0100

    fallocate: prefer FALLOC_FL_* flags from libc headers
    
    Reported-by: Sami Kerola <kerolasa@iki.fi>
    Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/fallocate.c b/sys-utils/fallocate.c
index 6a87673..cd35b2d 100644
--- a/sys-utils/fallocate.c
+++ b/sys-utils/fallocate.c
@@ -36,8 +36,9 @@
 # include <sys/syscall.h>
 #endif
 
-#ifdef HAVE_LINUX_FALLOC_H
-# include <linux/falloc.h>	/* for FALLOC_FL_* flags */
+#if defined(HAVE_LINUX_FALLOC_H) && \
+    (!defined(FALLOC_FL_KEEP_SIZE) || !defined(FALLOC_FL_PUNCH_HOLE))
+# include <linux/falloc.h>	/* non-libc fallback for FALLOC_FL_* flags */
 #endif
 
 #ifndef FALLOC_FL_KEEP_SIZE