Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-14 Thread Max Reitz
On 11.05.2014 19:26, Christoph Hellwig wrote: On Tue, May 06, 2014 at 09:00:54PM +0200, Max Reitz wrote: The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even compiled in in this case. However, there may be implement

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-11 Thread Christoph Hellwig
On Tue, May 06, 2014 at 09:00:54PM +0200, Max Reitz wrote: > The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if > FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even > compiled in in this case. However, there may be implementations which > support the latter but not t

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-09 Thread Paolo Bonzini
Il 06/05/2014 21:00, Max Reitz ha scritto: The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even compiled in in this case. However, there may be implementations which support the latter but not the former (e.g., NFSv4

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-08 Thread Max Reitz
On 07.05.2014 07:56, Markus Armbruster wrote: Eric Blake writes: On 05/06/2014 03:18 PM, Eric Blake wrote: ...if you are on a file system where SEEK_HOLE triggers the kernel fallback of "entire file is allocated", but where FIEMAP is wired up for that file system, would it make sense to have

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Markus Armbruster
Eric Blake writes: > On 05/06/2014 03:18 PM, Eric Blake wrote: > >> ...if you are on a file system where SEEK_HOLE triggers the kernel >> fallback of "entire file is allocated", but where FIEMAP is wired up for >> that file system, would it make sense to have try_seek_hole return -1 in >> situati

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Max Reitz
On 06.05.2014 23:47, Eric Blake wrote: On 05/06/2014 03:18 PM, Eric Blake wrote: ...if you are on a file system where SEEK_HOLE triggers the kernel fallback of "entire file is allocated", but where FIEMAP is wired up for that file system, would it make sense to have try_seek_hole return -1 in s

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Eric Blake
On 05/06/2014 03:18 PM, Eric Blake wrote: > ...if you are on a file system where SEEK_HOLE triggers the kernel > fallback of "entire file is allocated", but where FIEMAP is wired up for > that file system, would it make sense to have try_seek_hole return -1 in > situations where lseek(s->fd, 0, SE

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Max Reitz
On 06.05.2014 23:18, Eric Blake wrote: On 05/06/2014 01:00 PM, Max Reitz wrote: The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even compiled in in this case. However, there may be implementations which support the

Re: [Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Eric Blake
On 05/06/2014 01:00 PM, Max Reitz wrote: > The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if > FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even > compiled in in this case. However, there may be implementations which > support the latter but not the former (e.g., N

[Qemu-devel] [PATCH v2] block/raw-posix: Try both FIEMAP and SEEK_HOLE

2014-05-06 Thread Max Reitz
The current version of raw-posix always uses ioctl(FS_IOC_FIEMAP) if FIEMAP is available; lseek with SEEK_HOLE/SEEK_DATA are not even compiled in in this case. However, there may be implementations which support the latter but not the former (e.g., NFSv4.2) as well as vice versa. To cover both cas