md/md-bitmap: fix stats collection for external bitmaps

The bitmap_get_stats() function incorrectly returns -ENOENT for external
bitmaps.

Remove the external bitmap check as the statistics should be available
regardless of bitmap storage location.

Return -EINVAL only for invalid bitmap with no storage (neither in
superblock nor in external file).

Note: "bitmap_info.external" here refers to a bitmap stored in a separate
file (bitmap_file), not to external metadata.

Fixes: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime")
Signed-off-by: Zheng Qixing <zhengqixing@huawei.com>
Link: https://lore.kernel.org/linux-raid/20250403015322.2873369-1-zhengqixing@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 44ec9b17cfd33641f2e0d6eca77ca4f07db34f28..37b08f26c62f5d97b256733ee06b59a055318fe1 100644 (file)
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -2357,9 +2357,8 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)
 
        if (!bitmap)
                return -ENOENT;
-       if (bitmap->mddev->bitmap_info.external)
-               return -ENOENT;
-       if (!bitmap->storage.sb_page) /* no superblock */
+       if (!bitmap->mddev->bitmap_info.external &&
+           !bitmap->storage.sb_page)
                return -EINVAL;
        sb = kmap_local_page(bitmap->storage.sb_page);
        stats->sync_size = le64_to_cpu(sb->sync_size);