On 2011-07-25 13:25, Myklebust, Trond wrote: >> -----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. > I'd rather leave it as is so it's easier to test without CONFIG_MODULES. >> 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. I never new you can enable comments conditionally this way... It looks ok to me, I'll try it out and see how it shows in make *config Benny > > > 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 -- 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
