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

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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: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2011-05-11 14:26:30 +10:00
parent bedd86b777
commit 8258c53208
1 changed files with 6 additions and 4 deletions
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10
drivers/md/bitmap.c
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@ -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->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();