From: Jens Axboe axboe@kernel.dk
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...
[This issue only affects swapfiles on filesystems on top of blockdevs that implement rw_page ops (brd, zram, btt, pmem), and not on top of any other block devices, in contrast to the upstream commit fix.]
Fixes: dd6bd0d9c7db ("swap: use bdev_read_page() / bdev_write_page()") Cc: stable@vger.kernel.org # 4.4 Signed-off-by: Anthony Iliopoulos ailiop@suse.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/page_io.c | 11 +++-------- mm/swapfile.c | 2 +- 2 files changed, 4 insertions(+), 9 deletions(-)
--- a/mm/page_io.c +++ b/mm/page_io.c @@ -32,7 +32,6 @@ static struct bio *get_swap_bio(gfp_t gf bio = bio_alloc(gfp_flags, 1); if (bio) { bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev); - bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; bio->bi_end_io = end_io;
bio_add_page(bio, page, PAGE_SIZE, 0); @@ -244,11 +243,6 @@ out: return ret; }
-static sector_t swap_page_sector(struct page *page) -{ - return (sector_t)__page_file_index(page) << (PAGE_CACHE_SHIFT - 9); -} - int __swap_writepage(struct page *page, struct writeback_control *wbc, bio_end_io_t end_write_func) { @@ -297,7 +291,8 @@ int __swap_writepage(struct page *page, return ret; }
- ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc); + ret = bdev_write_page(sis->bdev, map_swap_page(page, &sis->bdev), + page, wbc); if (!ret) { count_vm_event(PSWPOUT); return 0; @@ -345,7 +340,7 @@ int swap_readpage(struct page *page) return ret; }
- ret = bdev_read_page(sis->bdev, swap_page_sector(page), page); + ret = bdev_read_page(sis->bdev, map_swap_page(page, &sis->bdev), page); if (!ret) { count_vm_event(PSWPIN); return 0; --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1653,7 +1653,7 @@ sector_t map_swap_page(struct page *page { swp_entry_t entry; entry.val = page_private(page); - return map_swap_entry(entry, bdev); + return map_swap_entry(entry, bdev) << (PAGE_SHIFT - 9); }
/*