From 8031c3ddc70ab93099e7d1814382dba39f57b43e Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Thu, 17 Aug 2017 10:35:11 -0700 Subject: md/bitmap: copy correct data for bitmap super raid5 cache could write bitmap superblock before bitmap superblock is initialized. The bitmap superblock is less than 512B. The current code will only copy the superblock to a new page and write the whole 512B, which will zero the the data after the superblock. Unfortunately the data could include bitmap, which we should preserve. The patch will make superblock read do 4k chunk and we always copy the 4k data to new page, so the superblock write will old data to disk and we don't change the bitmap. Reported-by: Song Liu Reviewed-by: Song Liu Cc: stable@vger.kernel.org (4.10+) Signed-off-by: Shaohua Li --- drivers/md/bitmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/md/bitmap.c') diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 40f3cd7eab0f..67e992185a24 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -625,7 +625,7 @@ re_read: err = read_sb_page(bitmap->mddev, offset, sb_page, - 0, sizeof(bitmap_super_t)); + 0, PAGE_SIZE); } if (err) return err; @@ -2118,7 +2118,7 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks, if (store.sb_page && bitmap->storage.sb_page) memcpy(page_address(store.sb_page), page_address(bitmap->storage.sb_page), - sizeof(bitmap_super_t)); + PAGE_SIZE); bitmap_file_unmap(&bitmap->storage); bitmap->storage = store; -- cgit v1.2.3 From e8a27f836f165c26f867ece7f31eb5c811692319 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 31 Aug 2017 10:23:25 +1000 Subject: md/bitmap: disable bitmap_resize for file-backed bitmaps. bitmap_resize() does not work for file-backed bitmaps. The buffer_heads are allocated and initialized when the bitmap is read from the file, but resize doesn't read from the file, it loads from the internal bitmap. When it comes time to write the new bitmap, the bh is non-existent and we crash. The common case when growing an array involves making the array larger, and that normally means making the bitmap larger. Doing that inside the kernel is possible, but would need more code. It is probably easier to require people who use file-backed bitmaps to remove them and re-add after a reshape. So this patch disables the resizing of arrays which have file-backed bitmaps. This is better than crashing. Reported-by: Zhilong Liu Fixes: d60b479d177a ("md/bitmap: add bitmap_resize function to allow bitmap resizing.") Cc: stable@vger.kernel.org (v3.5+). Signed-off-by: NeilBrown Signed-off-by: Shaohua Li --- drivers/md/bitmap.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/md/bitmap.c') diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index 67e992185a24..d2121637b4ab 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -2058,6 +2058,11 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks, long pages; struct bitmap_page *new_bp; + if (bitmap->storage.file && !init) { + pr_info("md: cannot resize file-based bitmap\n"); + return -EINVAL; + } + if (chunksize == 0) { /* If there is enough space, leave the chunk size unchanged, * else increase by factor of two until there is enough space. -- cgit v1.2.3