From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shaohua Li Subject: Re: [PATCH 09/13] md-cluster: always setup in-memory bitmap Date: Mon, 25 Apr 2016 10:45:21 -0700 Message-ID: <20160425174521.GB11993@kernel.org> References: <1461218294-4960-1-git-send-email-gqjiang@suse.com> <1461218294-4960-10-git-send-email-gqjiang@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1461218294-4960-10-git-send-email-gqjiang@suse.com> Sender: linux-raid-owner@vger.kernel.org To: Guoqing Jiang Cc: neilb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thu, Apr 21, 2016 at 01:58:10PM +0800, Guoqing Jiang wrote: > The in-memory bitmap for raid is allocated on demand, > then for cluster scenario, it is possible that slave > node which received RESYNCING message doesn't have the > in-memory bitmap when master node is perform resyncing, > so we can't make bitmap is match up well among each > nodes. > > So for cluster scenario, we need always preserve the > bitmap, and ensure the page will not be freed. And a > no_hijack flag is introduced to both bitmap_checkpage > and bitmap_get_counter, which makes cluster raid returns > fail once allocate failed. > > And the next patch is relied on this change since it > keeps sync bitmap among each nodes during resyncing > stage. > > Reviewed-by: NeilBrown > Signed-off-by: Guoqing Jiang > --- > drivers/md/bitmap.c | 59 +++++++++++++++++++++++++++++++++++++++++------------ > 1 file changed, 46 insertions(+), 13 deletions(-) > > diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c > index 7df6b4f..00cf1c1 100644 > --- a/drivers/md/bitmap.c > +++ b/drivers/md/bitmap.c > @@ -46,7 +46,7 @@ static inline char *bmname(struct bitmap *bitmap) > * allocated while we're using it > */ > static int bitmap_checkpage(struct bitmap_counts *bitmap, > - unsigned long page, int create) > + unsigned long page, int create, int no_hijack) > __releases(bitmap->lock) > __acquires(bitmap->lock) > { > @@ -90,6 +90,9 @@ __acquires(bitmap->lock) > > if (mappage == NULL) { > pr_debug("md/bitmap: map page allocation failed, hijacking\n"); > + /* We don't support hijack for cluster raid */ > + if (no_hijack) > + return -ENOMEM; > /* failed - set the hijacked flag so that we can use the > * pointer as a counter */ > if (!bitmap->bp[page].map) > @@ -1177,7 +1180,7 @@ static void bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset) > > static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap, > sector_t offset, sector_t *blocks, > - int create); > + int create, int no_hijack); > > /* > * bitmap daemon -- periodically wakes up to clean bits and flush pages > @@ -1257,7 +1260,7 @@ void bitmap_daemon_work(struct mddev *mddev) > } > bmc = bitmap_get_counter(counts, > block, > - &blocks, 0); > + &blocks, 0, 0); > > if (!bmc) { > j |= PAGE_COUNTER_MASK; > @@ -1307,7 +1310,7 @@ void bitmap_daemon_work(struct mddev *mddev) > > static bitmap_counter_t *bitmap_get_counter(struct bitmap_counts *bitmap, > sector_t offset, sector_t *blocks, > - int create) > + int create, int no_hijack) > __releases(bitmap->lock) > __acquires(bitmap->lock) > { > @@ -1321,7 +1324,7 @@ __acquires(bitmap->lock) > sector_t csize; > int err; > > - err = bitmap_checkpage(bitmap, page, create); > + err = bitmap_checkpage(bitmap, page, create, 0); > > if (bitmap->bp[page].hijacked || > bitmap->bp[page].map == NULL) bitmap_get_counter doesn't use the new no_hijack parameter. And you always pass 0 to this function. so looks this change isn't required.