> -----Original Message----- > From: Benny Halevy [mailto:bhalevy@xxxxxxxxxx] > Sent: Monday, July 25, 2011 10:50 AM > To: Myklebust, Trond > Cc: Jim Rees; linux-nfs@xxxxxxxxxxxxxxx; peter honeyman > Subject: Re: [PATCH v2 07/25] pnfsblock: add blocklayout Kconfig > option, Makefile, and stubs > > On 2011-07-25 10:38, Myklebust, Trond wrote: > >> -----Original Message----- > >> From: Benny Halevy [mailto:bhalevy@xxxxxxxxxx] > >> Sent: Monday, July 25, 2011 10:31 AM > >> To: Jim Rees > >> Cc: Myklebust, Trond; linux-nfs@xxxxxxxxxxxxxxx; peter honeyman > >> Subject: Re: [PATCH v2 07/25] pnfsblock: add blocklayout Kconfig > >> option, Makefile, and stubs > >> > >> On 2011-07-21 15:34, Jim Rees wrote: > >>> From: Fred Isaman <iisaman@xxxxxxxxxxxxxx> > >>> > >>> Define a configuration variable to enable/disable compilation of > the > >>> block driver code. > >>> > >>> Add the minimal structure for a pnfs block layout driver, and empty > >>> list-heads that will hold the extent data > >>> > >>> [pnfsblock: make NFS_V4_1 select PNFS_BLOCK] > >>> Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > >>> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxxxxxx> > >>> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> > >>> [pnfs-block: fix CONFIG_PNFS_BLOCK dependencies] > >>> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> > >>> Signed-off-by: Benny Halevy <benny@xxxxxxxxxx> > >>> [pnfsblock: SQUASHME: port block layout code] > >>> Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > >>> [pnfsblock: SQUASHME: adjust to API change] > >>> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxxxxxx> > >>> [pnfs: move pnfs_layout_type inline in nfs_inode] > >>> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> > >>> [blocklayout: encode_layoutcommit implementation] > >>> Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx> > >>> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> > >>> Signed-off-by: Benny Halevy <benny@xxxxxxxxxx> > >>> [pnfsblock: layout alloc and free] > >>> Signed-off-by: Fred Isaman <iisaman@xxxxxxxxxxxxxx> > >>> [pnfs: move pnfs_layout_type inline in nfs_inode] > >>> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx> > >>> Signed-off-by: Benny Halevy <benny@xxxxxxxxxx> > >>> [pnfsblock: define module alias] > >>> Signed-off-by: Peng Tao <peng_tao@xxxxxxx> > >>> --- > >>> fs/nfs/Kconfig | 8 ++- > >>> fs/nfs/Makefile | 1 + > >>> fs/nfs/blocklayout/Makefile | 5 + > >>> fs/nfs/blocklayout/blocklayout.c | 175 > >> ++++++++++++++++++++++++++++++++++++++ > >>> fs/nfs/blocklayout/blocklayout.h | 91 ++++++++++++++++++++ > >>> 5 files changed, 279 insertions(+), 1 deletions(-) > >>> create mode 100644 fs/nfs/blocklayout/Makefile > >>> create mode 100644 fs/nfs/blocklayout/blocklayout.c > >>> create mode 100644 fs/nfs/blocklayout/blocklayout.h > >>> > >>> diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig > >>> index 2cde5d9..be02077 100644 > >>> --- a/fs/nfs/Kconfig > >>> +++ b/fs/nfs/Kconfig > >>> @@ -79,15 +79,21 @@ config NFS_V4_1 > >>> depends on NFS_FS && NFS_V4 && EXPERIMENTAL > >>> select SUNRPC_BACKCHANNEL > >>> select PNFS_FILE_LAYOUT > >>> + select PNFS_BLOCK > >>> + select MD > >>> + select BLK_DEV_DM > >> > >> Why is PNFS_BLOCK enabled automatically in all cases? > >> That renders the use of modules for layout drivers totally useless. > >> I sort of understand that for PNFS_FILE_LAYOUT (when my > >> arm is twisted really hard behind my back :) since it > >> is an integral part of RFC5661 but what's the justification > >> for PNFS_BLOCK? and why blocks and not objects? > > > > The question is rather why did objects add a selectable compile > option? > > Just good citizenship :) > > > What is the point of not compiling a given layout driver if all the > > dependencies are met? > > Reducing build times... > Building a smaller kernel when modules are disabled... You can add a line with depends on m to ensure that it is always compiled as a module. I think that might be a good thing until we have nailed down all the issues with pNFS. > We're fine in terms of memory consumption when CONFIG_MODULES=y since > the > layout driver is loaded on demand but shouldn't be worried about > the other case? > > > > > IOW: The only thing I'd change above is the select MD and select > > BLK_DEV_DM: I'd prefer something like > > > > config PNFS_BLOCK > > depends on NFS_V4_1 && MD && BLK_DEV_DM > > default y > > This is closer to the original version. > However, selecting MD and BLK_DEV_DM was proven useful to automatically > take > care of the module dependencies without having to dive into details. Yes, but since the MD is a completely different layer that is not under our control (well, OK, Neil is still an NFS maintainer and an MD maintainer) then I'd prefer to leave it as a dependency. We can always add something like comment depends on NFS_V4_1 && !BLK_DEV_DM Please enable BLK_DEV_MD if you wish to enable the pNFS block driver. Cheers Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
