From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guoqing Jiang Subject: Re: [PATCH 09/13] md-cluster: always setup in-memory bitmap Date: Tue, 26 Apr 2016 11:22:37 +0800 Message-ID: <571EDEFD.3090103@suse.com> References: <1461218294-4960-1-git-send-email-gqjiang@suse.com> <1461218294-4960-10-git-send-email-gqjiang@suse.com> <20160425174521.GB11993@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160425174521.GB11993@kernel.org> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: neilb@suse.de, linux-raid@vger.kernel.org List-Id: linux-raid.ids On 04/26/2016 01:45 AM, Shaohua Li wrote: > 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. > The below part of this patch pass 1 to bitmap_checkpage, so it is needed. + /* For cluster raid, need to pre-allocate bitmap */ + if (mddev_is_clustered(bitmap->mddev)) { + unsigned long page; + for (page = 0; page < pages; page++) { + ret = bitmap_checkpage(&bitmap->counts, page, 1, 1); Thanks, Guoqing