On Thu, Dec 21, 2023 at 04:57:04PM +0800, Yu Kuai wrote: > @@ -3674,16 +3670,17 @@ struct btrfs_super_block > *btrfs_read_dev_one_super(struct block_device *bdev, > * Drop the page of the primary superblock, so later read will > * always read from the device. > */ > - invalidate_inode_pages2_range(mapping, > - bytenr >> PAGE_SHIFT, > + invalidate_bdev_range(bdev, bytenr >> PAGE_SHIFT, > (bytenr + BTRFS_SUPER_INFO_SIZE) >> PAGE_SHIFT); > } > > - page = read_cache_page_gfp(mapping, bytenr >> PAGE_SHIFT, GFP_NOFS); > - if (IS_ERR(page)) > - return ERR_CAST(page); > + nofs_flag = memalloc_nofs_save(); > + folio = bdev_read_folio(bdev, bytenr); > + memalloc_nofs_restore(nofs_flag);
This is the wrong way to use memalloc_nofs_save/restore. They should be used at the point that the filesystem takes/releases whatever lock is also used during reclaim. I don't know btrfs well enough to suggest what lock is missing these annotations.
