diff mbox series

[v4,7/7] fs/xfs: Add dedupe support for fsdax

Message ID 20210408120432.1063608-8-ruansy.fnst@fujitsu.com (mailing list archive)
State New
Headers show
Series fsdax,xfs: Add reflink&dedupe support for fsdax | expand

Commit Message

Shiyang Ruan April 8, 2021, 12:04 p.m. UTC
Add xfs_break_two_dax_layouts() to break layout for tow dax files.  Then
call compare range function only when files are both DAX or not.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
 fs/xfs/xfs_file.c    | 20 ++++++++++++++++++++
 fs/xfs/xfs_inode.c   |  8 +++++++-
 fs/xfs/xfs_inode.h   |  1 +
 fs/xfs/xfs_reflink.c |  5 +++--
 4 files changed, 31 insertions(+), 3 deletions(-)

Comments

Su Yue April 8, 2021, 1:12 p.m. UTC | #1
On Thu 08 Apr 2021 at 20:04, Shiyang Ruan 
<ruansy.fnst@fujitsu.com> wrote:

> Add xfs_break_two_dax_layouts() to break layout for tow dax 
> files.  Then
> call compare range function only when files are both DAX or not.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
>
Not family with xfs code but reading code make my sleep better :)
See bellow.

> ---
>  fs/xfs/xfs_file.c    | 20 ++++++++++++++++++++
>  fs/xfs/xfs_inode.c   |  8 +++++++-
>  fs/xfs/xfs_inode.h   |  1 +
>  fs/xfs/xfs_reflink.c |  5 +++--
>  4 files changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 5795d5d6f869..1fd457167c12 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -842,6 +842,26 @@ xfs_break_dax_layouts(
>  			0, 0, xfs_wait_dax_page(inode));
>  }
>
> +int
> +xfs_break_two_dax_layouts(
> +	struct inode		*src,
> +	struct inode		*dest)
> +{
> +	int			error;
> +	bool			retry = false;
> +
> +retry:
>
'retry = false;' ? since xfs_break_dax_layouts() won't
set retry to false if there is no busy page in inode->i_mapping.
Dead loop will happen if retry is true once.

> +	error = xfs_break_dax_layouts(src, &retry);
> +	if (error || retry)
> +		goto retry;
> +
> +	error = xfs_break_dax_layouts(dest, &retry);
> +	if (error || retry)
> +		goto retry;
> +
> +	return error;
> +}
> +
>  int
>  xfs_break_layouts(
>  	struct inode		*inode,
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index f93370bd7b1e..c01786917eef 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3713,8 +3713,10 @@ xfs_ilock2_io_mmap(
>  	struct xfs_inode	*ip2)
>  {
>  	int			ret;
> +	struct inode		*inode1 = VFS_I(ip1);
> +	struct inode		*inode2 = VFS_I(ip2);
>
> -	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), 
> VFS_I(ip2));
> +	ret = xfs_iolock_two_inodes_and_break_layout(inode1, inode2);
>  	if (ret)
>  		return ret;
>  	if (ip1 == ip2)
> @@ -3722,6 +3724,10 @@ xfs_ilock2_io_mmap(
>  	else
>  		xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,
>  				    ip2, XFS_MMAPLOCK_EXCL);
> +
> +	if (IS_DAX(inode1) && IS_DAX(inode2))
> +		ret = xfs_break_two_dax_layouts(inode1, inode2);
> +
ret is ignored here.

--
Su
>  	return 0;
>  }
>
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 88ee4c3930ae..5ef21924dddc 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -435,6 +435,7 @@ enum xfs_prealloc_flags {
>
>  int	xfs_update_prealloc_flags(struct xfs_inode *ip,
>  				  enum xfs_prealloc_flags flags);
> +int	xfs_break_two_dax_layouts(struct inode *inode1, struct 
> inode *inode2);
>  int	xfs_break_layouts(struct inode *inode, uint *iolock,
>  		enum layout_break_reason reason);
>
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index a4cd6e8a7aa0..4426bcc8a985 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -29,6 +29,7 @@
>  #include "xfs_iomap.h"
>  #include "xfs_sb.h"
>  #include "xfs_ag_resv.h"
> +#include <linux/dax.h>
>
>  /*
>   * Copy on Write of Shared Blocks
> @@ -1324,8 +1325,8 @@ xfs_reflink_remap_prep(
>  	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
>  		goto out_unlock;
>
> -	/* Don't share DAX file data for now. */
> -	if (IS_DAX(inode_in) || IS_DAX(inode_out))
> +	/* Don't share DAX file data with non-DAX file. */
> +	if (IS_DAX(inode_in) != IS_DAX(inode_out))
>  		goto out_unlock;
>
>  	if (!IS_DAX(inode_in))
Darrick J. Wong April 8, 2021, 11:04 p.m. UTC | #2
On Thu, Apr 08, 2021 at 08:04:32PM +0800, Shiyang Ruan wrote:
> Add xfs_break_two_dax_layouts() to break layout for tow dax files.  Then
> call compare range function only when files are both DAX or not.
> 
> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> ---
>  fs/xfs/xfs_file.c    | 20 ++++++++++++++++++++
>  fs/xfs/xfs_inode.c   |  8 +++++++-
>  fs/xfs/xfs_inode.h   |  1 +
>  fs/xfs/xfs_reflink.c |  5 +++--
>  4 files changed, 31 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 5795d5d6f869..1fd457167c12 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -842,6 +842,26 @@ xfs_break_dax_layouts(
>  			0, 0, xfs_wait_dax_page(inode));
>  }
>  
> +int
> +xfs_break_two_dax_layouts(
> +	struct inode		*src,
> +	struct inode		*dest)
> +{
> +	int			error;
> +	bool			retry = false;
> +
> +retry:
> +	error = xfs_break_dax_layouts(src, &retry);
> +	if (error || retry)
> +		goto retry;
> +
> +	error = xfs_break_dax_layouts(dest, &retry);
> +	if (error || retry)
> +		goto retry;
> +
> +	return error;
> +}
> +
>  int
>  xfs_break_layouts(
>  	struct inode		*inode,
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index f93370bd7b1e..c01786917eef 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3713,8 +3713,10 @@ xfs_ilock2_io_mmap(
>  	struct xfs_inode	*ip2)
>  {
>  	int			ret;
> +	struct inode		*inode1 = VFS_I(ip1);
> +	struct inode		*inode2 = VFS_I(ip2);
>  
> -	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
> +	ret = xfs_iolock_two_inodes_and_break_layout(inode1, inode2);
>  	if (ret)
>  		return ret;
>  	if (ip1 == ip2)
> @@ -3722,6 +3724,10 @@ xfs_ilock2_io_mmap(
>  	else
>  		xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,
>  				    ip2, XFS_MMAPLOCK_EXCL);
> +
> +	if (IS_DAX(inode1) && IS_DAX(inode2))
> +		ret = xfs_break_two_dax_layouts(inode1, inode2);

This is wrong on many levels.

The first problem is that xfs_break_two_dax_layouts calls
xfs_break_dax_layouts twice even if inode1 == inode2, which is
unnecessary.

The second problem is that xfs_break_dax_layouts can cycle the MMAPLOCK
on the inode that it's processing.  Since there are two inodes in play
here, you must be /very/ careful about maintaining correct locking order,
which for the MMAPLOCK is increasing order of xfs_inode.i_ino.  If you
drop the MMAPLOCK for the lower-numbered inode for any reason, you have
to drop both MMAPLOCKs and try again.

In other words, you have to replace all that nice MMAPLOCK code with a
new xfs_mmaplock_two_inodes_and_break_dax_layouts function that is
structured similarly to what xfs_iolock_two_inodes_and_break_layout
does for the IOLOCK and PNFS layouts.

> +
>  	return 0;
>  }
>  
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 88ee4c3930ae..5ef21924dddc 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -435,6 +435,7 @@ enum xfs_prealloc_flags {
>  
>  int	xfs_update_prealloc_flags(struct xfs_inode *ip,
>  				  enum xfs_prealloc_flags flags);
> +int	xfs_break_two_dax_layouts(struct inode *inode1, struct inode *inode2);
>  int	xfs_break_layouts(struct inode *inode, uint *iolock,
>  		enum layout_break_reason reason);
>  
> diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
> index a4cd6e8a7aa0..4426bcc8a985 100644
> --- a/fs/xfs/xfs_reflink.c
> +++ b/fs/xfs/xfs_reflink.c
> @@ -29,6 +29,7 @@
>  #include "xfs_iomap.h"
>  #include "xfs_sb.h"
>  #include "xfs_ag_resv.h"
> +#include <linux/dax.h>

Why is this necessary?

--D

>  
>  /*
>   * Copy on Write of Shared Blocks
> @@ -1324,8 +1325,8 @@ xfs_reflink_remap_prep(
>  	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
>  		goto out_unlock;
>  
> -	/* Don't share DAX file data for now. */
> -	if (IS_DAX(inode_in) || IS_DAX(inode_out))
> +	/* Don't share DAX file data with non-DAX file. */
> +	if (IS_DAX(inode_in) != IS_DAX(inode_out))
>  		goto out_unlock;
>  
>  	if (!IS_DAX(inode_in))
> -- 
> 2.31.0
> 
> 
>
Shiyang Ruan April 9, 2021, 1:56 a.m. UTC | #3
> -----Original Message-----
> From: Su Yue <l@damenly.su>
> Subject: Re: [PATCH v4 7/7] fs/xfs: Add dedupe support for fsdax
> 
> 
> On Thu 08 Apr 2021 at 20:04, Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote:
> 
> > Add xfs_break_two_dax_layouts() to break layout for tow dax files.
> > Then call compare range function only when files are both DAX or not.
> >
> > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
> >
> Not family with xfs code but reading code make my sleep better :) See bellow.
> 
> > ---
> >  fs/xfs/xfs_file.c    | 20 ++++++++++++++++++++
> >  fs/xfs/xfs_inode.c   |  8 +++++++-
> >  fs/xfs/xfs_inode.h   |  1 +
> >  fs/xfs/xfs_reflink.c |  5 +++--
> >  4 files changed, 31 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index
> > 5795d5d6f869..1fd457167c12 100644
> > --- a/fs/xfs/xfs_file.c
> > +++ b/fs/xfs/xfs_file.c
> > @@ -842,6 +842,26 @@ xfs_break_dax_layouts(
> >  			0, 0, xfs_wait_dax_page(inode));
> >  }
> >
> > +int
> > +xfs_break_two_dax_layouts(
> > +	struct inode		*src,
> > +	struct inode		*dest)
> > +{
> > +	int			error;
> > +	bool			retry = false;
> > +
> > +retry:
> >
> 'retry = false;' ? since xfs_break_dax_layouts() won't set retry to false if there is
> no busy page in inode->i_mapping.
> Dead loop will happen if retry is true once.

Yes, I should move 'retry=false;' under the retry label.

> 
> > +	error = xfs_break_dax_layouts(src, &retry);
> > +	if (error || retry)
> > +		goto retry;
> > +
> > +	error = xfs_break_dax_layouts(dest, &retry);
> > +	if (error || retry)
> > +		goto retry;
> > +
> > +	return error;
> > +}
> > +
> >  int
> >  xfs_break_layouts(
> >  	struct inode		*inode,
> > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index
> > f93370bd7b1e..c01786917eef 100644
> > --- a/fs/xfs/xfs_inode.c
> > +++ b/fs/xfs/xfs_inode.c
> > @@ -3713,8 +3713,10 @@ xfs_ilock2_io_mmap(
> >  	struct xfs_inode	*ip2)
> >  {
> >  	int			ret;
> > +	struct inode		*inode1 = VFS_I(ip1);
> > +	struct inode		*inode2 = VFS_I(ip2);
> >
> > -	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1),
> > VFS_I(ip2));
> > +	ret = xfs_iolock_two_inodes_and_break_layout(inode1, inode2);
> >  	if (ret)
> >  		return ret;
> >  	if (ip1 == ip2)
> > @@ -3722,6 +3724,10 @@ xfs_ilock2_io_mmap(
> >  	else
> >  		xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,
> >  				    ip2, XFS_MMAPLOCK_EXCL);
> > +
> > +	if (IS_DAX(inode1) && IS_DAX(inode2))
> > +		ret = xfs_break_two_dax_layouts(inode1, inode2);
> > +
> ret is ignored here.

Thanks, it's my mistake.


--
Thanks,
Ruan Shiyang.
> 
> --
> Su
> >  	return 0;
> >  }
> >
> > diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h index
> > 88ee4c3930ae..5ef21924dddc 100644
> > --- a/fs/xfs/xfs_inode.h
> > +++ b/fs/xfs/xfs_inode.h
> > @@ -435,6 +435,7 @@ enum xfs_prealloc_flags {
> >
> >  int	xfs_update_prealloc_flags(struct xfs_inode *ip,
> >  				  enum xfs_prealloc_flags flags);
> > +int	xfs_break_two_dax_layouts(struct inode *inode1, struct
> > inode *inode2);
> >  int	xfs_break_layouts(struct inode *inode, uint *iolock,
> >  		enum layout_break_reason reason);
> >
> > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index
> > a4cd6e8a7aa0..4426bcc8a985 100644
> > --- a/fs/xfs/xfs_reflink.c
> > +++ b/fs/xfs/xfs_reflink.c
> > @@ -29,6 +29,7 @@
> >  #include "xfs_iomap.h"
> >  #include "xfs_sb.h"
> >  #include "xfs_ag_resv.h"
> > +#include <linux/dax.h>
> >
> >  /*
> >   * Copy on Write of Shared Blocks
> > @@ -1324,8 +1325,8 @@ xfs_reflink_remap_prep(
> >  	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
> >  		goto out_unlock;
> >
> > -	/* Don't share DAX file data for now. */
> > -	if (IS_DAX(inode_in) || IS_DAX(inode_out))
> > +	/* Don't share DAX file data with non-DAX file. */
> > +	if (IS_DAX(inode_in) != IS_DAX(inode_out))
> >  		goto out_unlock;
> >
> >  	if (!IS_DAX(inode_in))
diff mbox series

Patch

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5795d5d6f869..1fd457167c12 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -842,6 +842,26 @@  xfs_break_dax_layouts(
 			0, 0, xfs_wait_dax_page(inode));
 }
 
+int
+xfs_break_two_dax_layouts(
+	struct inode		*src,
+	struct inode		*dest)
+{
+	int			error;
+	bool			retry = false;
+
+retry:
+	error = xfs_break_dax_layouts(src, &retry);
+	if (error || retry)
+		goto retry;
+
+	error = xfs_break_dax_layouts(dest, &retry);
+	if (error || retry)
+		goto retry;
+
+	return error;
+}
+
 int
 xfs_break_layouts(
 	struct inode		*inode,
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index f93370bd7b1e..c01786917eef 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3713,8 +3713,10 @@  xfs_ilock2_io_mmap(
 	struct xfs_inode	*ip2)
 {
 	int			ret;
+	struct inode		*inode1 = VFS_I(ip1);
+	struct inode		*inode2 = VFS_I(ip2);
 
-	ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
+	ret = xfs_iolock_two_inodes_and_break_layout(inode1, inode2);
 	if (ret)
 		return ret;
 	if (ip1 == ip2)
@@ -3722,6 +3724,10 @@  xfs_ilock2_io_mmap(
 	else
 		xfs_lock_two_inodes(ip1, XFS_MMAPLOCK_EXCL,
 				    ip2, XFS_MMAPLOCK_EXCL);
+
+	if (IS_DAX(inode1) && IS_DAX(inode2))
+		ret = xfs_break_two_dax_layouts(inode1, inode2);
+
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 88ee4c3930ae..5ef21924dddc 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -435,6 +435,7 @@  enum xfs_prealloc_flags {
 
 int	xfs_update_prealloc_flags(struct xfs_inode *ip,
 				  enum xfs_prealloc_flags flags);
+int	xfs_break_two_dax_layouts(struct inode *inode1, struct inode *inode2);
 int	xfs_break_layouts(struct inode *inode, uint *iolock,
 		enum layout_break_reason reason);
 
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index a4cd6e8a7aa0..4426bcc8a985 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -29,6 +29,7 @@ 
 #include "xfs_iomap.h"
 #include "xfs_sb.h"
 #include "xfs_ag_resv.h"
+#include <linux/dax.h>
 
 /*
  * Copy on Write of Shared Blocks
@@ -1324,8 +1325,8 @@  xfs_reflink_remap_prep(
 	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
 		goto out_unlock;
 
-	/* Don't share DAX file data for now. */
-	if (IS_DAX(inode_in) || IS_DAX(inode_out))
+	/* Don't share DAX file data with non-DAX file. */
+	if (IS_DAX(inode_in) != IS_DAX(inode_out))
 		goto out_unlock;
 
 	if (!IS_DAX(inode_in))