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Commit 193f1c93 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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[PATCH] md: always honour md bitmap being read from disk 



The code currently will ignore the bitmap if the array seem to be in-sync.
This is wrong if the array is degraded, and probably wrong anyway.  If the
bitmap says some chunks are not in in-sync, and the superblock says everything
IS in sync, then something is clearly wrong, and it is safer to trust the
bitmap.

Signed-off-by: default avatarNeil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent aa1595e9

drivers/md/bitmap.c

+23 −29
Original line number Diff line number Diff line
@@ -818,8 +818,7 @@ int bitmap_unplug(struct bitmap *bitmap) 
	return 0;

}



static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,

	unsigned long sectors, int in_sync);

static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset);

/* * bitmap_init_from_disk -- called at bitmap_create time to initialize

 * the in-memory bitmap from the on-disk bitmap -- also, sets up the

 * memory mapping of the bitmap file
@@ -828,7 +827,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, 
 *   previously kicked from the array, we mark all the bits as

 *   1's in order to cause a full resync.

 */

static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)

static int bitmap_init_from_disk(struct bitmap *bitmap)

{

	unsigned long i, chunks, index, oldindex, bit;

	struct page *page = NULL, *oldpage = NULL;
@@ -929,8 +928,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync) 
		}

		if (test_bit(bit, page_address(page))) {

			/* if the disk bit is set, set the memory bit */

			bitmap_set_memory_bits(bitmap,

					i << CHUNK_BLOCK_SHIFT(bitmap), 1, in_sync);

			bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap));

			bit_cnt++;

		}

	}
@@ -1426,14 +1424,13 @@ void bitmap_close_sync(struct bitmap *bitmap) 
	}

}



static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset,

				   unsigned long sectors, int in_sync)

static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset)

{

	/* For each chunk covered by any of these sectors, set the

	 * counter to 1 and set resync_needed unless in_sync.  They should all

	 * counter to 1 and set resync_needed.  They should all

	 * be 0 at this point

	 */

	while (sectors) {



	int secs;

	bitmap_counter_t *bmc;

	spin_lock_irq(&bitmap->lock);
@@ -1444,17 +1441,13 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, 
	}

	if (! *bmc) {

		struct page *page;

			*bmc = 1 | (in_sync? 0 : NEEDED_MASK);

		*bmc = 1 | NEEDED_MASK;

		bitmap_count_page(bitmap, offset, 1);

		page = filemap_get_page(bitmap, offset >> CHUNK_BLOCK_SHIFT(bitmap));

		set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);

	}

	spin_unlock_irq(&bitmap->lock);

		if (sectors > secs)

			sectors -= secs;

		else

			sectors = 0;

	}



}



/*
@@ -1565,7 +1558,8 @@ int bitmap_create(mddev_t *mddev) 


	/* now that we have some pages available, initialize the in-memory

	 * bitmap from the on-disk bitmap */

	err = bitmap_init_from_disk(bitmap, mddev->recovery_cp == MaxSector);

	err = bitmap_init_from_disk(bitmap);



	if (err)

		return err;