From 60fdceaa91ad3bd7d7171b7280492d7438492d5c 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 063c0c1e112b..136a929648ef 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -473,6 +473,7 @@ 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 60a66a58b9bf..bcf27d057253 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -260,11 +260,6 @@ out: 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 7947633d3ced..f6964212c6c8 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -221,6 +221,19 @@ 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.