2d30d31ea3
Since commit 62c230bc17
("mm: add support for a filesystem to activate
swap files and use direct_IO for writing swap pages"), swap_writepage()
calls direct_IO on swap files. However, in that case the page isn't
redirtied if I/O fails, and is therefore handled afterwards as if it has
been successfully written to the swap file, leading to memory corruption
when the page is eventually swapped back in.
This patch sets the page dirty when direct_IO() fails. It fixes a
memory corruption that happened while using swap-over-NFS.
Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org> [3.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
304 lines
7.0 KiB
C
304 lines
7.0 KiB
C
/*
|
|
* linux/mm/page_io.c
|
|
*
|
|
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
|
|
*
|
|
* Swap reorganised 29.12.95,
|
|
* Asynchronous swapping added 30.12.95. Stephen Tweedie
|
|
* Removed race in async swapping. 14.4.1996. Bruno Haible
|
|
* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
|
|
* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
|
|
*/
|
|
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/frontswap.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
static struct bio *get_swap_bio(gfp_t gfp_flags,
|
|
struct page *page, bio_end_io_t end_io)
|
|
{
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(gfp_flags, 1);
|
|
if (bio) {
|
|
bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
|
|
bio->bi_sector <<= PAGE_SHIFT - 9;
|
|
bio->bi_io_vec[0].bv_page = page;
|
|
bio->bi_io_vec[0].bv_len = PAGE_SIZE;
|
|
bio->bi_io_vec[0].bv_offset = 0;
|
|
bio->bi_vcnt = 1;
|
|
bio->bi_idx = 0;
|
|
bio->bi_size = PAGE_SIZE;
|
|
bio->bi_end_io = end_io;
|
|
}
|
|
return bio;
|
|
}
|
|
|
|
void end_swap_bio_write(struct bio *bio, int err)
|
|
{
|
|
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
|
|
struct page *page = bio->bi_io_vec[0].bv_page;
|
|
|
|
if (!uptodate) {
|
|
SetPageError(page);
|
|
/*
|
|
* We failed to write the page out to swap-space.
|
|
* Re-dirty the page in order to avoid it being reclaimed.
|
|
* Also print a dire warning that things will go BAD (tm)
|
|
* very quickly.
|
|
*
|
|
* Also clear PG_reclaim to avoid rotate_reclaimable_page()
|
|
*/
|
|
set_page_dirty(page);
|
|
printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
|
|
imajor(bio->bi_bdev->bd_inode),
|
|
iminor(bio->bi_bdev->bd_inode),
|
|
(unsigned long long)bio->bi_sector);
|
|
ClearPageReclaim(page);
|
|
}
|
|
end_page_writeback(page);
|
|
bio_put(bio);
|
|
}
|
|
|
|
void end_swap_bio_read(struct bio *bio, int err)
|
|
{
|
|
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
|
|
struct page *page = bio->bi_io_vec[0].bv_page;
|
|
|
|
if (!uptodate) {
|
|
SetPageError(page);
|
|
ClearPageUptodate(page);
|
|
printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
|
|
imajor(bio->bi_bdev->bd_inode),
|
|
iminor(bio->bi_bdev->bd_inode),
|
|
(unsigned long long)bio->bi_sector);
|
|
} else {
|
|
SetPageUptodate(page);
|
|
}
|
|
unlock_page(page);
|
|
bio_put(bio);
|
|
}
|
|
|
|
int generic_swapfile_activate(struct swap_info_struct *sis,
|
|
struct file *swap_file,
|
|
sector_t *span)
|
|
{
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
unsigned blocks_per_page;
|
|
unsigned long page_no;
|
|
unsigned blkbits;
|
|
sector_t probe_block;
|
|
sector_t last_block;
|
|
sector_t lowest_block = -1;
|
|
sector_t highest_block = 0;
|
|
int nr_extents = 0;
|
|
int ret;
|
|
|
|
blkbits = inode->i_blkbits;
|
|
blocks_per_page = PAGE_SIZE >> blkbits;
|
|
|
|
/*
|
|
* Map all the blocks into the extent list. This code doesn't try
|
|
* to be very smart.
|
|
*/
|
|
probe_block = 0;
|
|
page_no = 0;
|
|
last_block = i_size_read(inode) >> blkbits;
|
|
while ((probe_block + blocks_per_page) <= last_block &&
|
|
page_no < sis->max) {
|
|
unsigned block_in_page;
|
|
sector_t first_block;
|
|
|
|
first_block = bmap(inode, probe_block);
|
|
if (first_block == 0)
|
|
goto bad_bmap;
|
|
|
|
/*
|
|
* It must be PAGE_SIZE aligned on-disk
|
|
*/
|
|
if (first_block & (blocks_per_page - 1)) {
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
|
|
for (block_in_page = 1; block_in_page < blocks_per_page;
|
|
block_in_page++) {
|
|
sector_t block;
|
|
|
|
block = bmap(inode, probe_block + block_in_page);
|
|
if (block == 0)
|
|
goto bad_bmap;
|
|
if (block != first_block + block_in_page) {
|
|
/* Discontiguity */
|
|
probe_block++;
|
|
goto reprobe;
|
|
}
|
|
}
|
|
|
|
first_block >>= (PAGE_SHIFT - blkbits);
|
|
if (page_no) { /* exclude the header page */
|
|
if (first_block < lowest_block)
|
|
lowest_block = first_block;
|
|
if (first_block > highest_block)
|
|
highest_block = first_block;
|
|
}
|
|
|
|
/*
|
|
* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
|
|
*/
|
|
ret = add_swap_extent(sis, page_no, 1, first_block);
|
|
if (ret < 0)
|
|
goto out;
|
|
nr_extents += ret;
|
|
page_no++;
|
|
probe_block += blocks_per_page;
|
|
reprobe:
|
|
continue;
|
|
}
|
|
ret = nr_extents;
|
|
*span = 1 + highest_block - lowest_block;
|
|
if (page_no == 0)
|
|
page_no = 1; /* force Empty message */
|
|
sis->max = page_no;
|
|
sis->pages = page_no - 1;
|
|
sis->highest_bit = page_no - 1;
|
|
out:
|
|
return ret;
|
|
bad_bmap:
|
|
printk(KERN_ERR "swapon: swapfile has holes\n");
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* We may have stale swap cache pages in memory: notice
|
|
* them here and get rid of the unnecessary final write.
|
|
*/
|
|
int swap_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (try_to_free_swap(page)) {
|
|
unlock_page(page);
|
|
goto out;
|
|
}
|
|
if (frontswap_store(page) == 0) {
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
end_page_writeback(page);
|
|
goto out;
|
|
}
|
|
ret = __swap_writepage(page, wbc, end_swap_bio_write);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int __swap_writepage(struct page *page, struct writeback_control *wbc,
|
|
void (*end_write_func)(struct bio *, int))
|
|
{
|
|
struct bio *bio;
|
|
int ret = 0, rw = WRITE;
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct kiocb kiocb;
|
|
struct file *swap_file = sis->swap_file;
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
struct iovec iov = {
|
|
.iov_base = kmap(page),
|
|
.iov_len = PAGE_SIZE,
|
|
};
|
|
|
|
init_sync_kiocb(&kiocb, swap_file);
|
|
kiocb.ki_pos = page_file_offset(page);
|
|
kiocb.ki_left = PAGE_SIZE;
|
|
kiocb.ki_nbytes = PAGE_SIZE;
|
|
|
|
unlock_page(page);
|
|
ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
|
|
&kiocb, &iov,
|
|
kiocb.ki_pos, 1);
|
|
kunmap(page);
|
|
if (ret == PAGE_SIZE) {
|
|
count_vm_event(PSWPOUT);
|
|
ret = 0;
|
|
} else {
|
|
set_page_dirty(page);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
bio = get_swap_bio(GFP_NOIO, page, end_write_func);
|
|
if (bio == NULL) {
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
if (wbc->sync_mode == WB_SYNC_ALL)
|
|
rw |= REQ_SYNC;
|
|
count_vm_event(PSWPOUT);
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
submit_bio(rw, bio);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int swap_readpage(struct page *page)
|
|
{
|
|
struct bio *bio;
|
|
int ret = 0;
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
VM_BUG_ON(!PageLocked(page));
|
|
VM_BUG_ON(PageUptodate(page));
|
|
if (frontswap_load(page) == 0) {
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
goto out;
|
|
}
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct file *swap_file = sis->swap_file;
|
|
struct address_space *mapping = swap_file->f_mapping;
|
|
|
|
ret = mapping->a_ops->readpage(swap_file, page);
|
|
if (!ret)
|
|
count_vm_event(PSWPIN);
|
|
return ret;
|
|
}
|
|
|
|
bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
|
|
if (bio == NULL) {
|
|
unlock_page(page);
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
count_vm_event(PSWPIN);
|
|
submit_bio(READ, bio);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int swap_set_page_dirty(struct page *page)
|
|
{
|
|
struct swap_info_struct *sis = page_swap_info(page);
|
|
|
|
if (sis->flags & SWP_FILE) {
|
|
struct address_space *mapping = sis->swap_file->f_mapping;
|
|
return mapping->a_ops->set_page_dirty(page);
|
|
} else {
|
|
return __set_page_dirty_no_writeback(page);
|
|
}
|
|
}
|