在 2025/03/03 11:39, Su Yue 写道:
In clustermd, separate write-intent-bitmaps are used for each cluster
node:
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 the first 4k sb area of node 1 will never be updated
through filemap_write_page().
This bug causes hang of mdadm/clustermd_tests/01r1_Grow_resize.
Here use (pg_index % bitmap->storage.file_pages) to make calculation
of bitmap_limit correct.
Fixes: ab99a87542f1 ("md/md-bitmap: fix writing non bitmap pages")
Signed-off-by: Su Yue <glass.su@xxxxxxxx>
---
Changelog:
v3:
Amend commit message suggested by Heming.
v2:
Remove unintended change calling md_super_write().
---
drivers/md/md-bitmap.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Applied to md-6.15
Thanks,
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)
