Hi Glass, The code looks good to me. The commit log needs to be revised. On 3/2/25 12:39, Su Yue wrote:
In clustermd, Separate write-intent-bitmaps are used for each cluster node:
Change 'Separate' to lowercase 'separate'.
0 4k 8k 12k ------------------------------------------------------------------- | idle | md super | bm super [0] + bits | | bm bits[0, contd] | bm super[1] + bits | bm bits[1, contd] | | bm super[2] + bits | bm bits [2, contd] | bm super[3] + bits | | bm bits [3, contd] | | | So in node 1, pg_index in __write_sb_page() could equal to bitmap->storage.file_pages. Then bitmap_limit will be calculated to 0. md_super_write() will be called with 0 size. That means node the first 4k sb area of node 1 will never be updated through filemap_write_page().
"That means node the ...", should remove the word 'node'? - Heming
This bug causes hang of mdadm/clustermd_tests/01r1_Grow_resize. Here use (pg_index % bitmap->storage.file_pages) to calculation of bitmap_limit correct. Fixes: ab99a87542f1 ("md/md-bitmap: fix writing non bitmap pages") Signed-off-by: Su Yue <glass.su@xxxxxxxx> --- drivers/md/md-bitmap.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index 23c09d22fcdb..9ae6cc8e30cb 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -426,8 +426,8 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap, struct block_device *bdev; struct mddev *mddev = bitmap->mddev; struct bitmap_storage *store = &bitmap->storage; - unsigned int bitmap_limit = (bitmap->storage.file_pages - pg_index) << - PAGE_SHIFT; + unsigned long num_pages = bitmap->storage.file_pages; + unsigned int bitmap_limit = (num_pages - pg_index % num_pages) << PAGE_SHIFT; loff_t sboff, offset = mddev->bitmap_info.offset; sector_t ps = pg_index * PAGE_SIZE / SECTOR_SIZE; unsigned int size = PAGE_SIZE; @@ -436,7 +436,7 @@ static int __write_sb_page(struct md_rdev *rdev, struct bitmap *bitmap,bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;/* we compare length (page numbers), not page offset. */ - if ((pg_index - store->sb_index) == store->file_pages - 1) { + if ((pg_index - store->sb_index) == num_pages - 1) { unsigned int last_page_size = store->bytes & (PAGE_SIZE - 1);if (last_page_size == 0)
