> -----Original Message----- > From: Neil Brown [mailto:neilb@xxxxxxx] > Sent: Wednesday, June 16, 2010 6:54 AM > To: Kwolek, Adam > Cc: linux-raid@xxxxxxxxxxxxxxx; Williams, Dan J; Ciechanowski, Ed > Subject: Re: [md PATCH 2/5] md: Enable reshape for external metadata > > On Wed, 9 Jun 2010 15:21:05 +0100 > "Kwolek, Adam" <adam.kwolek@xxxxxxxxx> wrote: > > > (md: Online Capacity Expansion for IMSM) > > Reshape can't go forward for external metadatas due to fact, that > internal md flags are updated during native meta writing. For external > metadatas > > md_update_sb() is not called (reshape process is blocked). > > To take carry about md flags in external metadata array case and > allow reshape to roll over, md_update_sb() is called in similar way to > native metadata. The difference is that metadata is not stored to disks > by md, but externally by mdmon. > > I agree there is a problem here but I think you are approaching it the > wrong > way. We need to make sure the problem flag doesn't get set when > external > metadata is used. > > I found something similar (maybe the same thing) when writing the dm- > raid456 > module. Does that patch: > > http://neil.brown.name/git?p=md;a=commitdiff;h=3b930b37e50702f97f8fad6d > 7f5ee6d3f268394e > > solve the problem for you? > > Thanks, > NeilBrown It almost solves problem. To make it solved the following change I have to add: md/md.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/md/md.c b/md/md.c index e9b5d67..01e88cd 100644 --- a/md/md.c +++ b/md/md.c @@ -6437,7 +6437,8 @@ int md_allow_write(mddev_t *mddev) spin_lock_irq(&mddev->write_lock); if (mddev->in_sync) { mddev->in_sync = 0; - set_bit(MD_CHANGE_CLEAN, &mddev->flags); + if (mddev->persistent) + set_bit(MD_CHANGE_CLEAN, &mddev->flags); if (mddev->safemode_delay && mddev->safemode == 0) mddev->safemode = 1; This closes MD_CHANGE_CLEAN flag management for me. What do you think about this? Another thing is waiting during reshape for metadata update on MD_CHANGE_DEVS flag. To roll reshape I've added the following code (instead calling md_ubdate_sb()): diff --git a/md/md.c b/md/md.c index 01e88cd..539b323 100644 --- a/md/md.c +++ b/md/md.c @@ -6896,8 +6896,17 @@ void md_check_recovery(mddev_t *mddev) (mddev->external == 0 && mddev->safemode == 1) || (mddev->safemode == 2 && ! atomic_read(&mddev->writes_pending) && !mddev->in_sync && mddev->recovery_cp == MaxSector) - )) + )) { + if ((mddev->external) && (mddev->flags)) { + /* FIXME: + * for external metadata checkpointing purposes + * put communication with userspace here + */ + clear_bit(MD_CHANGE_DEVS, &mddev->flags); + wake_up(&mddev->sb_wait); + } return; + } if (mddev_trylock(mddev)) { int spares = 0; This change we can reuse for checkpointing purposes. External metadata updates can be triggered in the same moments as native one (reuse internal md communication mechanisms). What is your opinion about this? BR Adam -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
