From: Domenico Andreoli domenico.andreoli@linux.com
[ Upstream commit 56939e014a6c212b317414faa307029e2e80c3b9 ]
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: dc617f29dbe5 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- fs/block_dev.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c index d612468ee66bf..34644ce4b5025 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -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 { @@ -1975,7 +1976,8 @@ 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))