From 04b049ac9cb4eb425998f690fbd416757a7c9b15 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 2 Mar 2021 14:53:21 -0700 Subject: [PATCH] swap: fix swapfile read/write offset commit caf6912f3f4af7232340d500a4a2008f81b93f14 upstream. We're not factoring in the start of the file for where to write and read the swapfile, which leads to very unfortunate side effects of writing where we should not be... Fixes: dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()") Signed-off-by: Jens Axboe Cc: Anthony Iliopoulos Signed-off-by: Greg Kroah-Hartman --- include/linux/swap.h | 1 + mm/page_io.c | 5 ----- mm/swapfile.c | 13 +++++++++++++ 3 files changed, 14 insertions(+), 5 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 667935c0dbd4c..fbc6805358da0 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -484,6 +484,7 @@ struct backing_dev_info; extern int init_swap_address_space(unsigned int type, unsigned long nr_pages); extern void exit_swap_address_space(unsigned int type); extern struct swap_info_struct *get_swap_device(swp_entry_t entry); +sector_t swap_page_sector(struct page *page); static inline void put_swap_device(struct swap_info_struct *si) { diff --git a/mm/page_io.c b/mm/page_io.c index 433df12633495..96479817ffae3 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -273,11 +273,6 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) return ret; } -static sector_t swap_page_sector(struct page *page) -{ - return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9); -} - static inline void count_swpout_vm_event(struct page *page) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE diff --git a/mm/swapfile.c b/mm/swapfile.c index 16db9d1ebcbf3..5256c10049b0f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -220,6 +220,19 @@ offset_to_swap_extent(struct swap_info_struct *sis, unsigned long offset) BUG(); } +sector_t swap_page_sector(struct page *page) +{ + struct swap_info_struct *sis = page_swap_info(page); + struct swap_extent *se; + sector_t sector; + pgoff_t offset; + + offset = __page_file_index(page); + se = offset_to_swap_extent(sis, offset); + sector = se->start_block + (offset - se->start_page); + return sector << (PAGE_SHIFT - 9); +} + /* * swap allocation tell device that a cluster of swap can now be discarded, * to allow the swap device to optimize its wear-levelling.