Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342

Darrick J. Wong
2020-02-25T20:26:47Z

On Sun, Feb 23, 2020 at 08:03:11PM +0100, Domenico Andreoli wrote:
> On Fri, Feb 21, 2020 at 04:23:19PM -0800, Darrick J. Wong wrote:
> >
> > Ok, third try. Does the following work? This is a little more
> > selective in that it only disables the write protection on the swap
> > device/file that uswusp is going to write to.
>
> Yes it works but also verified that once the S_SWAPFILE bit is cleared
> it's never restored, therefore the protecton is gone after the first
> hibernation.

Ok, good. Now can you try the third part, which ought to re-apply
S_SWAPFILE after a successful resume, please? Assuming this works, I
think we're ready with a fixpatch.

--D

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 1e99f7ac1d7e..add93e205850 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -458,6 +458,7 @@ extern void swap_free(swp_entry_t);
extern void swapcache_free_entries(swp_entry_t *entries, int n);
extern int free_swap_and_cache(swp_entry_t);
extern int swap_type_of(dev_t, sector_t, struct block_device **);
+extern void swap_relockall(void);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct page *, struct block_device **);
extern sector_t swapdev_block(int, pgoff_t);
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 77438954cc2b..b11f7037ce5e 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -271,6 +271,8 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
break;
}
error = hibernation_restore(data->platform_support);
+ if (!error)
+ swap_relockall();
break;

case SNAPSHOT_FREE:
@@ -372,10 +374,17 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
*/
swdev = new_decode_dev(swap_area.dev);
if (swdev) {
+ struct block_device *bd;
+
offset = swap_area.offset;
- data->swap = swap_type_of(swdev, offset, NULL);
+ data->swap = swap_type_of(swdev, offset, &bd);
if (data->swap < 0)
error = -ENODEV;
+
+ inode_lock(bd->bd_inode);
+ bd->bd_inode->i_flags &= ~S_SWAPFILE;
+ inode_unlock(bd->bd_inode);
+ bdput(bd);
} else {
data->swap = -1;
error = -EINVAL;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index b2a2e45c9a36..a64dcba10db6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1799,6 +1799,32 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p)
return -ENODEV;
}

+/* Re-lock swap devices after resuming from userspace suspend. */
+void swap_relockall(void)
+{
+ int type;
+
+ spin_lock(&swap_lock);
+ for (type = 0; type < nr_swapfiles; type++) {
+ struct swap_info_struct *sis = swap_info[type];
+ struct block_device *bdev = bdgrab(sis->bdev);
+
+ /*
+ * uswsusp only knows how to suspend to block devices, so we
+ * can skip swap files.
+ */
+ if (!(sis->flags & SWP_WRITEOK) ||
+ !(sis->flags & SWP_BLKDEV))
+ continue;
+
+ inode_lock(bd->bd_inode);
+ bd->bd_inode->i_flags |= S_SWAPFILE;
+ inode_unlock(bd->bd_inode);
+ bdput(bd);
+ }
+ spin_unlock(&swap_lock);
+}
+
/*
* Get the (PAGE_SIZE) block corresponding to given offset on the swapdev
* corresponding to given index in swap_info (swap type).