[Qemu-devel] [PATCH 1/1] block: add gluster ifdef guard checks for SEEK_DATA/SEEK_HOLE support

[Qemu-devel] [PATCH 1/1] block: add gluster ifdef guard checks for SEEK_DATA/SEEK_HOLE support

[Jeff Cody]

Add checks to see if the system compiling QEMU has support for
SEEK_HOLE/SEEK_DATA.  If the system does not, we will flag that seek
data is unsupported in gluster.

Note: this is not a check on whether the gluster server itself supports
SEEK_DATA (that is already done during runtime), but rather if the
compilation environment supports SEEK_DATA.

Signed-off-by: Jeff Cody <jcody@redhat.com>
---

Note: this patch is untested on older systems that do not support SEEK_DATA
(e.g.. RHEL6).  This won't be pulled into my tree until it is verified.


 block/gluster.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/block/gluster.c b/block/gluster.c
index e7bd13c..acb1934 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -672,8 +672,10 @@ static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
  */
 static bool qemu_gluster_test_seek(struct glfs_fd *fd)
 {
-    off_t ret, eof;
+    off_t ret = 0;
+    off_t eof;
 
+#if defined SEEK_HOLE && defined SEEK_DATA
     eof = glfs_lseek(fd, 0, SEEK_END);
     if (eof < 0) {
         /* this should never occur */
@@ -682,6 +684,7 @@ static bool qemu_gluster_test_seek(struct glfs_fd *fd)
 
     /* this should always fail with ENXIO if SEEK_DATA is supported */
     ret = glfs_lseek(fd, eof, SEEK_DATA);
+#endif
     return (ret < 0) && (errno == ENXIO);
 }
 
@@ -1185,9 +1188,10 @@ static int find_allocation(BlockDriverState *bs, off_t start,
     off_t offs;
 
     if (!s->supports_seek_data) {
-        return -ENOTSUP;
+        goto exit;
     }
 
+#if defined SEEK_HOLE && defined SEEK_DATA
     /*
      * SEEK_DATA cases:
      * D1. offs == start: start is in data
@@ -1251,6 +1255,9 @@ static int find_allocation(BlockDriverState *bs, off_t start,
 
     /* D1 and H1 */
     return -EBUSY;
+#endif
+exit:
+    return -ENOTSUP;
 }
 
 /*
-- 
2.7.4

Re: [Qemu-devel] [PATCH 1/1] block: add gluster ifdef guard checks for SEEK_DATA/SEEK_HOLE support

[Eric Blake]

[-- Attachment #1: Type: text/plain, Size: 1196 bytes --]

On 10/06/2016 10:53 PM, Jeff Cody wrote:
> Add checks to see if the system compiling QEMU has support for
> SEEK_HOLE/SEEK_DATA.  If the system does not, we will flag that seek
> data is unsupported in gluster.
> 
> Note: this is not a check on whether the gluster server itself supports
> SEEK_DATA (that is already done during runtime), but rather if the
> compilation environment supports SEEK_DATA.
> 
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
> 
> Note: this patch is untested on older systems that do not support SEEK_DATA
> (e.g.. RHEL6).  This won't be pulled into my tree until it is verified.
> 

  CC      block/gluster.o
block/gluster.c: In function ‘qemu_gluster_test_seek’:
block/gluster.c:676: warning: unused variable ‘eof’
block/gluster.c: In function ‘find_allocation’:
block/gluster.c:1188: warning: unused variable ‘offs’

but compilation succeeded in spite of the warning.  Would be nice to
clean that up for -Werror users.

Tested-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 604 bytes --]

Re: [Qemu-devel] [PATCH 1/1] block: add gluster ifdef guard checks for SEEK_DATA/SEEK_HOLE support

[Jeff Cody]

On Fri, Oct 07, 2016 at 09:20:54AM -0500, Eric Blake wrote:
> On 10/06/2016 10:53 PM, Jeff Cody wrote:
> > Add checks to see if the system compiling QEMU has support for
> > SEEK_HOLE/SEEK_DATA.  If the system does not, we will flag that seek
> > data is unsupported in gluster.
> > 
> > Note: this is not a check on whether the gluster server itself supports
> > SEEK_DATA (that is already done during runtime), but rather if the
> > compilation environment supports SEEK_DATA.
> > 
> > Signed-off-by: Jeff Cody <jcody@redhat.com>
> > ---
> > 
> > Note: this patch is untested on older systems that do not support SEEK_DATA
> > (e.g.. RHEL6).  This won't be pulled into my tree until it is verified.
> > 
> 
>   CC      block/gluster.o
> block/gluster.c: In function ‘qemu_gluster_test_seek’:
> block/gluster.c:676: warning: unused variable ‘eof’
> block/gluster.c: In function ‘find_allocation’:
> block/gluster.c:1188: warning: unused variable ‘offs’
> 
> but compilation succeeded in spite of the warning.  Would be nice to
> clean that up for -Werror users.
> 
> Tested-by: Eric Blake <eblake@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>

Thanks Eric.  I'll clean that up for a v2.

Jeff