On Thu, Oct 13, 2016 at 03:25:57PM +0800, Qu Wenruo wrote: > At 10/13/2016 01:26 AM, David Sterba wrote: > > On Wed, Oct 12, 2016 at 10:01:27PM +0800, Qu Wenruo wrote: > >> > >> > >> On 10/12/2016 09:58 PM, Abhay Sachan wrote: > >>> Hi, > >>> I tried building latest btrfs progs on CentOS 6, "./configure" failed > >>> with the error: > >>> > >>> checking for FIEMAP_EXTENT_SHARED defined in linux/fiemap.h... no > >>> configure: error: no definition of FIEMAP_EXTENT_SHARED found > >>> > >>> Any ideas what am I lacking in the system? > >> > >> Your kernel is too old and its header doesn't support > >> FIEMAP_EXTENT_SHARED flag for fiemap ioctl. > > > > As this is not the first time, I wonder if we could provide a defintion > > of the macro in progs, regardless of the installed headers. Note that > > this does not mean the running kernel is old. Previously the user said > > he was running a 4.4 kernel [1] (or it could be any other kernel > > version). For that combination of headers and running kernel, I think > > it's ok to add a fallback definition. > > Yes, fallback definition is good for case like running kernel supports > SHARED_EXTENT flag, but not kernel header. > > But I'm a little concerned about such fallback definition will lead to > corrupted result for "fi du".
Well, not corrupted bug wrong. The shared data will be reported as exclusive. > >> And since that flag is very important for tools like "btrfs filesystem > >> du", for old kernel doesn't support EXTENT_SHARED flag, we have no > >> choice but abort configuration. > > > > The check was added to configure so it's caught earlier than during > > build. The 'fi du' command is useful, but not IMO critical to stop the > > build. > > What about just disabling subcommands using SHARED_EXTENT flag? > Like "fi du". This would need to be checked at runtime, based only on kernel version. I think we can do that, print a warning in 'fi du' but otherwise let it continue. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
