Commit 8258c532 authored by NeilBrown's avatar NeilBrown
Browse files

md/bitmap: fix saving of events_cleared and other state. 



If a bitmap is found to be 'stale' the events_cleared value
is set to match 'events'.
However if the array is degraded this does not get stored on disk.
This can subsequently lead to incorrect behaviour.

So change bitmap_update_sb to always update events_cleared in the
superblock from the known events_cleared.
For neatness also set ->state from ->flags.
This requires updating ->state whenever we update ->flags, which makes
sense anyway.

This is suitable for any active -stable release.

cc: stable@kernel.org
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent bedd86b7

drivers/md/bitmap.c

+6 −4
Original line number Diff line number Diff line
@@ -493,11 +493,11 @@ void bitmap_update_sb(struct bitmap *bitmap) 
	spin_unlock_irqrestore(&bitmap->lock, flags);

	sb = kmap_atomic(bitmap->sb_page, KM_USER0);

	sb->events = cpu_to_le64(bitmap->mddev->events);

	if (bitmap->mddev->events < bitmap->events_cleared) {

	if (bitmap->mddev->events < bitmap->events_cleared)

		/* rocking back to read-only */

		bitmap->events_cleared = bitmap->mddev->events;

	sb->events_cleared = cpu_to_le64(bitmap->events_cleared);

	}

	sb->state = cpu_to_le32(bitmap->flags);

	/* Just in case these have been changed via sysfs: */

	sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);

	sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
@@ -618,7 +618,7 @@ success: 
	if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)

		bitmap->flags |= BITMAP_HOSTENDIAN;

	bitmap->events_cleared = le64_to_cpu(sb->events_cleared);

	if (sb->state & cpu_to_le32(BITMAP_STALE))

	if (bitmap->flags & BITMAP_STALE)

		bitmap->events_cleared = bitmap->mddev->events;

	err = 0;

out:
@@ -652,9 +652,11 @@ static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits, 
	switch (op) {

	case MASK_SET:

		sb->state |= cpu_to_le32(bits);

		bitmap->flags |= bits;

		break;

	case MASK_UNSET:

		sb->state &= cpu_to_le32(~bits);

		bitmap->flags &= ~bits;

		break;

	default:

		BUG();

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