On Tue, Apr 26, 2016 at 11:22:37AM +0800, Guoqing Jiang wrote:
>
>
> 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 <neilb@xxxxxxxx>
> >>Signed-off-by: Guoqing Jiang <gqjiang@xxxxxxxx>
> >>---
> >> 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);
I mean bitmap_get_counter(). You add no_hijack parameter, but not use it
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