Commit c84400c8 authored May 02, 2016 by Guoqing Jiang Committed by Shaohua Li May 04, 2016

md-cluster/bitmap: unplug bitmap to sync dirty pages to disk



This patch is doing two distinct but related things.

1. It adds bitmap_unplug() for the main bitmap (mddev->bitmap).  As bit
have been set, BITMAP_PAGE_DIRTY is set so bitmap_deamon_work() will
not write those pages out in its regular scans, only bitmap_unplug()
will.  If there are no writes to the array, bitmap_unplug() won't be
called, so we need to call it explicitly here.

2. bitmap_write_all() is a bit of a confusing interface as it doesn't
actually write anything.  The current code for writing "bitmap" works
but this change makes it a bit clearer.

Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

parent 23cea66a

drivers/md/bitmap.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -1924,14 +1924,14 @@ int bitmap_copy_from_slot(struct mddev *mddev, int slot,

		if (clear_bits) {
		bitmap_update_sb(bitmap);
		/* Setting this for the ev_page should be enough.
		* And we do not require both write_all and PAGE_DIRT either
		*/
		/* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
		* BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
		for (i = 0; i < bitmap->storage.file_pages; i++)
		set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
		bitmap_write_all(bitmap);
		if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
		set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
		bitmap_unplug(bitmap);
		}
		bitmap_unplug(mddev->bitmap);
		*low = lo;
		*high = hi;
		err:

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