Messages in this thread Patch in this message | | | Date | Fri, 21 Feb 2020 16:23:19 -0800 | From | "Darrick J. Wong" <> | Subject | Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342 |
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On Fri, Feb 14, 2020 at 10:15:24PM +0100, Domenico Andreoli wrote: > [ added linux-pm ] > > On Thu, Feb 13, 2020 at 11:41:35AM -0800, Darrick J. Wong wrote: > > On Thu, Feb 13, 2020 at 11:34:10AM -0800, Darrick J. Wong wrote: > > > > > > Well ... you could try the in-kernel hibernate (which I think is what > > > 'systemctl hibernate' does), though you'd lose the nifty features of > > > µswsusp. > > Indeed 'systemctl hibernate' works perfectly with v5.6-rc1 in my setup. > > > > In the end, though, I'll probably have to revert all those IS_SWAPFILE > > > checks (at least if CONFIG_HIBERNATION=y) since it's not fair to force > > > you to totally reconfigure your hibernation setup. > > > > Also, does the following partial revert fix uswsusp for you? It'll > > allow the direct writes that uswsusp wants to do, while leaving the rest > > (mmap writes) in place. > > > > --D > > > > diff --git a/fs/block_dev.c b/fs/block_dev.c > > index 69bf2fb6f7cd..077d9fa6b87d 100644 > > --- a/fs/block_dev.c > > +++ b/fs/block_dev.c > > @@ -2001,8 +2001,10 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) > > if (bdev_read_only(I_BDEV(bd_inode))) > > return -EPERM; > > > > +#ifndef CONFIG_HIBERNATION > > if (IS_SWAPFILE(bd_inode)) > > return -ETXTBSY; > > +#endif > > This alone is enough to make uswsusp work again. > > I propose this alternative: > > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -2001,7 +2001,8 @@ 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)) > + /* Hibernation might happen via uswsusp, let it write to the swap */ > + if (IS_SWAPFILE(bd_inode) && !IS_ENABLED(CONFIG_HIBERNATION)) > return -ETXTBSY; > > if (!iov_iter_count(from)) > > I looked for a more selective way to enable writes to swap at runtime, > so I tried with system_entering_hibernation() but it's not yet armed > at the point in which uswsusp wants to write to the swap and therefore > it does not work. > > --- 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 { > @@ -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)) > + /* Hibernation might happen via uswsusp, let it write to the swap */ > + if (IS_SWAPFILE(bd_inode) && !system_entering_hibernation()) > return -ETXTBSY; > > if (!iov_iter_count(from)) > > > if (!iov_iter_count(from)) > > return 0; > > diff --git a/mm/filemap.c b/mm/filemap.c > > index 1784478270e1..3df3211abe25 100644 > > --- a/mm/filemap.c > > +++ b/mm/filemap.c > > @@ -2920,8 +2920,10 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) > > loff_t count; > > int ret; > > > > +#ifndef CONFIG_HIBERNATION > > if (IS_SWAPFILE(inode)) > > return -ETXTBSY; > > +#endif > > > > if (!iov_iter_count(from)) > > return 0; > > The above is not needed in my case but I'm not sure it would not be > needed in some other configuration of uswsusp.
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.
--D
diff --git a/kernel/power/user.c b/kernel/power/user.c index 77438954cc2b..a3ae9cbbfcf0 100644 --- a/kernel/power/user.c +++ b/kernel/power/user.c @@ -372,10 +372,17 @@ 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;
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