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hibernate: Allow uswsusp to write to swap 

It turns out that there is one use case for programs being able to
write to swap devices, and that is the userspace hibernation code.

Quick fix: disable the S_SWAPFILE check if hibernation is configured.

Fixes: dc617f29db ("vfs: don't allow writes to swap files")
Reported-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reported-by: Marian Klein <mkleinsoft@gmail.com>
Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
alistair/sensors
Domenico Andreoli 2020-03-23 08:22:15 -07:00 committed by Darrick J. Wong
parent 98d54f81e3
commit 56939e014a
1 changed files with 3 additions and 1 deletions
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4
fs/block_dev.c
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@ -34,6 +34,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/falloc.h>
#include <linux/uaccess.h>
#include <linux/suspend.h>
#include "internal.h"
struct bdev_inode {
@ -2001,7 +2002,8 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (bdev_read_only(I_BDEV(bd_inode)))
return -EPERM;
if (IS_SWAPFILE(bd_inode))
/* uswsusp needs write permission to the swap */
if (IS_SWAPFILE(bd_inode) && !hibernation_available())
return -ETXTBSY;
if (!iov_iter_count(from))