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* Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342
       [not found]       ` <20200213194135.GF6870@magnolia>
@ 2020-02-14 21:15         ` Domenico Andreoli
  2020-02-19  5:03           ` Darrick J. Wong
  2020-02-22  0:23           ` Darrick J. Wong
  0 siblings, 2 replies; 4+ messages in thread
From: Domenico Andreoli @ 2020-02-14 21:15 UTC (permalink / raw)
  To: Darrick J. Wong
  Cc: Christoph Hellwig, Linus Torvalds, Linux Kernel Mailing List, linux-pm

[ 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.

Dom

-- 
rsa4096: 3B10 0CA1 8674 ACBA B4FE  FCD2 CE5B CF17 9960 DE13
ed25519: FFB4 0CC3 7F2E 091D F7DA  356E CC79 2832 ED38 CB05

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342
  2020-02-14 21:15         ` Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342 Domenico Andreoli
@ 2020-02-19  5:03           ` Darrick J. Wong
  2020-02-22  0:23           ` Darrick J. Wong
  1 sibling, 0 replies; 4+ messages in thread
From: Darrick J. Wong @ 2020-02-19  5:03 UTC (permalink / raw)
  To: Christoph Hellwig, Linus Torvalds, Linux Kernel Mailing List, linux-pm

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.

As I suspected, the in-kernel hibernate can write the memory image to
the swap file just fine...

> > > 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))

...but maybe we could do something a little more targeted?

>                 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.

Hmm.  I was poking around in the uswsusp code and I /think/ it prepares
the kernel for the userspace-driven hibernation by calling the ioctl
SNAPSHOT_SET_SWAP_FILE on the device that it's going to use.  If that's
true, we could have it clear S_SWAPFILE on the chosen device, though I'd
have to do some more digging to figure out how to restore the flag after
resuming from hibernation.

--D

> 
> --- 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.
> 
> Dom
> 
> -- 
> rsa4096: 3B10 0CA1 8674 ACBA B4FE  FCD2 CE5B CF17 9960 DE13
> ed25519: FFB4 0CC3 7F2E 091D F7DA  356E CC79 2832 ED38 CB05

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342
  2020-02-14 21:15         ` Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342 Domenico Andreoli
  2020-02-19  5:03           ` Darrick J. Wong
@ 2020-02-22  0:23           ` Darrick J. Wong
  2020-02-23 19:03             ` Domenico Andreoli
  1 sibling, 1 reply; 4+ messages in thread
From: Darrick J. Wong @ 2020-02-22  0:23 UTC (permalink / raw)
  To: Christoph Hellwig, Linus Torvalds, Linux Kernel Mailing List, linux-pm

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;

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342
  2020-02-22  0:23           ` Darrick J. Wong
@ 2020-02-23 19:03             ` Domenico Andreoli
  0 siblings, 0 replies; 4+ messages in thread
From: Domenico Andreoli @ 2020-02-23 19:03 UTC (permalink / raw)
  To: Darrick J. Wong
  Cc: Christoph Hellwig, Linus Torvalds, Linux Kernel Mailing List, linux-pm

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.

> 
> --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;

-- 
rsa4096: 3B10 0CA1 8674 ACBA B4FE  FCD2 CE5B CF17 9960 DE13
ed25519: FFB4 0CC3 7F2E 091D F7DA  356E CC79 2832 ED38 CB05

^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2020-02-14 21:15         ` Regression: hibernation is broken since e6bc9de714972cac34daa1dc1567ee48a47a9342 Domenico Andreoli
2020-02-19  5:03           ` Darrick J. Wong
2020-02-22  0:23           ` Darrick J. Wong
2020-02-23 19:03             ` Domenico Andreoli

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