[PATCH 1/2] xfs: factor out a new xfs_log_force_inode helper

[PATCH 1/2] xfs: factor out a new xfs_log_force_inode helper

[Christoph Hellwig]

Create a new helper to force the log up to the last LSN touching an
inode.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_export.c | 14 +-------------
 fs/xfs/xfs_file.c   | 12 +-----------
 fs/xfs/xfs_inode.c  | 19 +++++++++++++++++++
 fs/xfs/xfs_inode.h  |  1 +
 4 files changed, 22 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
index f1372f9046e3..5a4b0119143a 100644
--- a/fs/xfs/xfs_export.c
+++ b/fs/xfs/xfs_export.c
@@ -15,7 +15,6 @@
 #include "xfs_trans.h"
 #include "xfs_inode_item.h"
 #include "xfs_icache.h"
-#include "xfs_log.h"
 #include "xfs_pnfs.h"
 
 /*
@@ -221,18 +220,7 @@ STATIC int
 xfs_fs_nfs_commit_metadata(
 	struct inode		*inode)
 {
-	struct xfs_inode	*ip = XFS_I(inode);
-	struct xfs_mount	*mp = ip->i_mount;
-	xfs_lsn_t		lsn = 0;
-
-	xfs_ilock(ip, XFS_ILOCK_SHARED);
-	if (xfs_ipincount(ip))
-		lsn = ip->i_itemp->ili_last_lsn;
-	xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
-	if (!lsn)
-		return 0;
-	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
+	return xfs_log_force_inode(XFS_I(inode));
 }
 
 const struct export_operations xfs_export_operations = {
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index b8a4a3f29b36..68e1cbb3cfcc 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -80,19 +80,9 @@ xfs_dir_fsync(
 	int			datasync)
 {
 	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
-	struct xfs_mount	*mp = ip->i_mount;
-	xfs_lsn_t		lsn = 0;
 
 	trace_xfs_dir_fsync(ip);
-
-	xfs_ilock(ip, XFS_ILOCK_SHARED);
-	if (xfs_ipincount(ip))
-		lsn = ip->i_itemp->ili_last_lsn;
-	xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
-	if (!lsn)
-		return 0;
-	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
+	return xfs_log_force_inode(ip);
 }
 
 STATIC int
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index c5077e6326c7..e48fc835cb85 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3951,3 +3951,22 @@ xfs_irele(
 	trace_xfs_irele(ip, _RET_IP_);
 	iput(VFS_I(ip));
 }
+
+/*
+ * Ensure all commited transactions touching the inode are written to the log.
+ */
+int
+xfs_log_force_inode(
+	struct xfs_inode	*ip)
+{
+	xfs_lsn_t		lsn = 0;
+
+	xfs_ilock(ip, XFS_ILOCK_SHARED);
+	if (xfs_ipincount(ip))
+		lsn = ip->i_itemp->ili_last_lsn;
+	xfs_iunlock(ip, XFS_ILOCK_SHARED);
+
+	if (!lsn)
+		return 0;
+	return xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, NULL);
+}
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 492e53992fa9..c6a63f6764a6 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -426,6 +426,7 @@ int		xfs_itruncate_extents_flags(struct xfs_trans **,
 				struct xfs_inode *, int, xfs_fsize_t, int);
 void		xfs_iext_realloc(xfs_inode_t *, int, int);
 
+int		xfs_log_force_inode(struct xfs_inode *ip);
 void		xfs_iunpin_wait(xfs_inode_t *);
 #define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
 
-- 
2.25.1

[PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Christoph Hellwig]

Reflink should force the log out to disk if the filesystem was mounted
with wsync, the same as most other operations in xfs.

Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 68e1cbb3cfcc..4b8bdecc3863 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1059,7 +1059,11 @@ xfs_file_remap_range(
 
 	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
 			remap_flags);
+	if (ret)
+		goto out_unlock;
 
+	if (mp->m_flags & XFS_MOUNT_WSYNC)
+		xfs_log_force_inode(dest);
 out_unlock:
 	xfs_reflink_remap_unlock(file_in, file_out);
 	if (ret)
-- 
2.25.1

Re: [PATCH 1/2] xfs: factor out a new xfs_log_force_inode helper

[Darrick J. Wong]

On Fri, Apr 03, 2020 at 02:55:21PM +0200, Christoph Hellwig wrote:
> Create a new helper to force the log up to the last LSN touching an
> inode.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks reasonable,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_export.c | 14 +-------------
>  fs/xfs/xfs_file.c   | 12 +-----------
>  fs/xfs/xfs_inode.c  | 19 +++++++++++++++++++
>  fs/xfs/xfs_inode.h  |  1 +
>  4 files changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
> index f1372f9046e3..5a4b0119143a 100644
> --- a/fs/xfs/xfs_export.c
> +++ b/fs/xfs/xfs_export.c
> @@ -15,7 +15,6 @@
>  #include "xfs_trans.h"
>  #include "xfs_inode_item.h"
>  #include "xfs_icache.h"
> -#include "xfs_log.h"
>  #include "xfs_pnfs.h"
>  
>  /*
> @@ -221,18 +220,7 @@ STATIC int
>  xfs_fs_nfs_commit_metadata(
>  	struct inode		*inode)
>  {
> -	struct xfs_inode	*ip = XFS_I(inode);
> -	struct xfs_mount	*mp = ip->i_mount;
> -	xfs_lsn_t		lsn = 0;
> -
> -	xfs_ilock(ip, XFS_ILOCK_SHARED);
> -	if (xfs_ipincount(ip))
> -		lsn = ip->i_itemp->ili_last_lsn;
> -	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> -
> -	if (!lsn)
> -		return 0;
> -	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
> +	return xfs_log_force_inode(XFS_I(inode));
>  }
>  
>  const struct export_operations xfs_export_operations = {
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index b8a4a3f29b36..68e1cbb3cfcc 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -80,19 +80,9 @@ xfs_dir_fsync(
>  	int			datasync)
>  {
>  	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
> -	struct xfs_mount	*mp = ip->i_mount;
> -	xfs_lsn_t		lsn = 0;
>  
>  	trace_xfs_dir_fsync(ip);
> -
> -	xfs_ilock(ip, XFS_ILOCK_SHARED);
> -	if (xfs_ipincount(ip))
> -		lsn = ip->i_itemp->ili_last_lsn;
> -	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> -
> -	if (!lsn)
> -		return 0;
> -	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
> +	return xfs_log_force_inode(ip);
>  }
>  
>  STATIC int
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index c5077e6326c7..e48fc835cb85 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3951,3 +3951,22 @@ xfs_irele(
>  	trace_xfs_irele(ip, _RET_IP_);
>  	iput(VFS_I(ip));
>  }
> +
> +/*
> + * Ensure all commited transactions touching the inode are written to the log.
> + */
> +int
> +xfs_log_force_inode(
> +	struct xfs_inode	*ip)
> +{
> +	xfs_lsn_t		lsn = 0;
> +
> +	xfs_ilock(ip, XFS_ILOCK_SHARED);
> +	if (xfs_ipincount(ip))
> +		lsn = ip->i_itemp->ili_last_lsn;
> +	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> +
> +	if (!lsn)
> +		return 0;
> +	return xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, NULL);
> +}
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 492e53992fa9..c6a63f6764a6 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -426,6 +426,7 @@ int		xfs_itruncate_extents_flags(struct xfs_trans **,
>  				struct xfs_inode *, int, xfs_fsize_t, int);
>  void		xfs_iext_realloc(xfs_inode_t *, int, int);
>  
> +int		xfs_log_force_inode(struct xfs_inode *ip);
>  void		xfs_iunpin_wait(xfs_inode_t *);
>  #define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
>  
> -- 
> 2.25.1
> 

Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Darrick J. Wong]

On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> Reflink should force the log out to disk if the filesystem was mounted
> with wsync, the same as most other operations in xfs.
> 
> Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Seems like a cleaner implementation than the one I came up with,

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_file.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 68e1cbb3cfcc..4b8bdecc3863 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
>  
>  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
>  			remap_flags);
> +	if (ret)
> +		goto out_unlock;
>  
> +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> +		xfs_log_force_inode(dest);
>  out_unlock:
>  	xfs_reflink_remap_unlock(file_in, file_out);
>  	if (ret)
> -- 
> 2.25.1
> 

Re: [PATCH 1/2] xfs: factor out a new xfs_log_force_inode helper

[Brian Foster]

On Fri, Apr 03, 2020 at 02:55:21PM +0200, Christoph Hellwig wrote:
> Create a new helper to force the log up to the last LSN touching an
> inode.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_export.c | 14 +-------------
>  fs/xfs/xfs_file.c   | 12 +-----------
>  fs/xfs/xfs_inode.c  | 19 +++++++++++++++++++
>  fs/xfs/xfs_inode.h  |  1 +
>  4 files changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/fs/xfs/xfs_export.c b/fs/xfs/xfs_export.c
> index f1372f9046e3..5a4b0119143a 100644
> --- a/fs/xfs/xfs_export.c
> +++ b/fs/xfs/xfs_export.c
> @@ -15,7 +15,6 @@
>  #include "xfs_trans.h"
>  #include "xfs_inode_item.h"
>  #include "xfs_icache.h"
> -#include "xfs_log.h"
>  #include "xfs_pnfs.h"
>  
>  /*
> @@ -221,18 +220,7 @@ STATIC int
>  xfs_fs_nfs_commit_metadata(
>  	struct inode		*inode)
>  {
> -	struct xfs_inode	*ip = XFS_I(inode);
> -	struct xfs_mount	*mp = ip->i_mount;
> -	xfs_lsn_t		lsn = 0;
> -
> -	xfs_ilock(ip, XFS_ILOCK_SHARED);
> -	if (xfs_ipincount(ip))
> -		lsn = ip->i_itemp->ili_last_lsn;
> -	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> -
> -	if (!lsn)
> -		return 0;
> -	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
> +	return xfs_log_force_inode(XFS_I(inode));
>  }
>  
>  const struct export_operations xfs_export_operations = {
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index b8a4a3f29b36..68e1cbb3cfcc 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -80,19 +80,9 @@ xfs_dir_fsync(
>  	int			datasync)
>  {
>  	struct xfs_inode	*ip = XFS_I(file->f_mapping->host);
> -	struct xfs_mount	*mp = ip->i_mount;
> -	xfs_lsn_t		lsn = 0;
>  
>  	trace_xfs_dir_fsync(ip);
> -
> -	xfs_ilock(ip, XFS_ILOCK_SHARED);
> -	if (xfs_ipincount(ip))
> -		lsn = ip->i_itemp->ili_last_lsn;
> -	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> -
> -	if (!lsn)
> -		return 0;
> -	return xfs_log_force_lsn(mp, lsn, XFS_LOG_SYNC, NULL);
> +	return xfs_log_force_inode(ip);
>  }
>  
>  STATIC int
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index c5077e6326c7..e48fc835cb85 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3951,3 +3951,22 @@ xfs_irele(
>  	trace_xfs_irele(ip, _RET_IP_);
>  	iput(VFS_I(ip));
>  }
> +
> +/*
> + * Ensure all commited transactions touching the inode are written to the log.
> + */
> +int
> +xfs_log_force_inode(
> +	struct xfs_inode	*ip)
> +{
> +	xfs_lsn_t		lsn = 0;
> +
> +	xfs_ilock(ip, XFS_ILOCK_SHARED);
> +	if (xfs_ipincount(ip))
> +		lsn = ip->i_itemp->ili_last_lsn;
> +	xfs_iunlock(ip, XFS_ILOCK_SHARED);
> +
> +	if (!lsn)
> +		return 0;
> +	return xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC, NULL);
> +}
> diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
> index 492e53992fa9..c6a63f6764a6 100644
> --- a/fs/xfs/xfs_inode.h
> +++ b/fs/xfs/xfs_inode.h
> @@ -426,6 +426,7 @@ int		xfs_itruncate_extents_flags(struct xfs_trans **,
>  				struct xfs_inode *, int, xfs_fsize_t, int);
>  void		xfs_iext_realloc(xfs_inode_t *, int, int);
>  
> +int		xfs_log_force_inode(struct xfs_inode *ip);
>  void		xfs_iunpin_wait(xfs_inode_t *);
>  #define xfs_ipincount(ip)	((unsigned int) atomic_read(&ip->i_pincount))
>  
> -- 
> 2.25.1
> 

Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Brian Foster]

On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> Reflink should force the log out to disk if the filesystem was mounted
> with wsync, the same as most other operations in xfs.
> 

Isn't WSYNC for namespace operations? Why is this needed for reflink?

> Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")

At a glance this looks like a refactoring patch. What does this fix?

Brian

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/xfs/xfs_file.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 68e1cbb3cfcc..4b8bdecc3863 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
>  
>  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
>  			remap_flags);
> +	if (ret)
> +		goto out_unlock;
>  
> +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> +		xfs_log_force_inode(dest);
>  out_unlock:
>  	xfs_reflink_remap_unlock(file_in, file_out);
>  	if (ret)
> -- 
> 2.25.1
> 

Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Darrick J. Wong]

On Mon, Apr 06, 2020 at 08:14:37AM -0400, Brian Foster wrote:
> On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> > Reflink should force the log out to disk if the filesystem was mounted
> > with wsync, the same as most other operations in xfs.
> > 
> 
> Isn't WSYNC for namespace operations? Why is this needed for reflink?

The manpage says that 'wsync' (the mount option) is for making namespace
operations synchronous.

However, xfs_init_fs_context sets XFS_MOUNT_WSYNC if the admin set
the 'sync' mount option, which makes all IO synchronous.

> > Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
> 
> At a glance this looks like a refactoring patch. What does this fix?

It probably ought to be 862bb360ef569f ("xfs: reflink extents from one
file to another") but so much of that was refactored for 5.0 that
backporting this fix will require changing a totally different function
(xfs_reflink_remap_range) in a totally different file (xfs_reflink.c).

--D

> Brian
> 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> >  fs/xfs/xfs_file.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > index 68e1cbb3cfcc..4b8bdecc3863 100644
> > --- a/fs/xfs/xfs_file.c
> > +++ b/fs/xfs/xfs_file.c
> > @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
> >  
> >  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
> >  			remap_flags);
> > +	if (ret)
> > +		goto out_unlock;
> >  
> > +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> > +		xfs_log_force_inode(dest);
> >  out_unlock:
> >  	xfs_reflink_remap_unlock(file_in, file_out);
> >  	if (ret)
> > -- 
> > 2.25.1
> > 
> 

Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Brian Foster]

On Mon, Apr 06, 2020 at 08:31:54AM -0700, Darrick J. Wong wrote:
> On Mon, Apr 06, 2020 at 08:14:37AM -0400, Brian Foster wrote:
> > On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> > > Reflink should force the log out to disk if the filesystem was mounted
> > > with wsync, the same as most other operations in xfs.
> > > 
> > 
> > Isn't WSYNC for namespace operations? Why is this needed for reflink?
> 
> The manpage says that 'wsync' (the mount option) is for making namespace
> operations synchronous.
> 
> However, xfs_init_fs_context sets XFS_MOUNT_WSYNC if the admin set
> the 'sync' mount option, which makes all IO synchronous.
>

Ok.. so we're considering reflink a form of I/O.. I suppose that makes
sense, though it would be nice to explain that in the commit log...

Reviewed-by: Brian Foster <bfoster@redhat.com>

> > > Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
> > 
> > At a glance this looks like a refactoring patch. What does this fix?
> 
> It probably ought to be 862bb360ef569f ("xfs: reflink extents from one
> file to another") but so much of that was refactored for 5.0 that
> backporting this fix will require changing a totally different function
> (xfs_reflink_remap_range) in a totally different file (xfs_reflink.c).
> 
> --D
> 
> > Brian
> > 
> > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > ---
> > >  fs/xfs/xfs_file.c | 4 ++++
> > >  1 file changed, 4 insertions(+)
> > > 
> > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > index 68e1cbb3cfcc..4b8bdecc3863 100644
> > > --- a/fs/xfs/xfs_file.c
> > > +++ b/fs/xfs/xfs_file.c
> > > @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
> > >  
> > >  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
> > >  			remap_flags);
> > > +	if (ret)
> > > +		goto out_unlock;
> > >  
> > > +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> > > +		xfs_log_force_inode(dest);
> > >  out_unlock:
> > >  	xfs_reflink_remap_unlock(file_in, file_out);
> > >  	if (ret)
> > > -- 
> > > 2.25.1
> > > 
> > 
> 

Re: [PATCH 2/2] xfs: reflink should force the log out if mounted with wsync

[Darrick J. Wong]

On Mon, Apr 06, 2020 at 12:04:37PM -0400, Brian Foster wrote:
> On Mon, Apr 06, 2020 at 08:31:54AM -0700, Darrick J. Wong wrote:
> > On Mon, Apr 06, 2020 at 08:14:37AM -0400, Brian Foster wrote:
> > > On Fri, Apr 03, 2020 at 02:55:22PM +0200, Christoph Hellwig wrote:
> > > > Reflink should force the log out to disk if the filesystem was mounted
> > > > with wsync, the same as most other operations in xfs.
> > > > 
> > > 
> > > Isn't WSYNC for namespace operations? Why is this needed for reflink?
> > 
> > The manpage says that 'wsync' (the mount option) is for making namespace
> > operations synchronous.
> > 
> > However, xfs_init_fs_context sets XFS_MOUNT_WSYNC if the admin set
> > the 'sync' mount option, which makes all IO synchronous.
> >
> 
> Ok.. so we're considering reflink a form of I/O.. I suppose that makes
> sense, though it would be nice to explain that in the commit log...

Ok, I'll add the following:

    [Note: XFS_MOUNT_WSYNC is set when the admin mounts the filesystem
    with either the 'wsync' or 'sync' mount options, which effectively means
    that we're classifying reflink/dedupe as IO operations and making them
    synchronous when required.]

Thanks for reviewing. :)

--D

> Reviewed-by: Brian Foster <bfoster@redhat.com>
> 
> > > > Fixes: 3fc9f5e409319 ("xfs: remove xfs_reflink_remap_range")
> > > 
> > > At a glance this looks like a refactoring patch. What does this fix?
> > 
> > It probably ought to be 862bb360ef569f ("xfs: reflink extents from one
> > file to another") but so much of that was refactored for 5.0 that
> > backporting this fix will require changing a totally different function
> > (xfs_reflink_remap_range) in a totally different file (xfs_reflink.c).
> > 
> > --D
> > 
> > > Brian
> > > 
> > > > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > > > ---
> > > >  fs/xfs/xfs_file.c | 4 ++++
> > > >  1 file changed, 4 insertions(+)
> > > > 
> > > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > > index 68e1cbb3cfcc..4b8bdecc3863 100644
> > > > --- a/fs/xfs/xfs_file.c
> > > > +++ b/fs/xfs/xfs_file.c
> > > > @@ -1059,7 +1059,11 @@ xfs_file_remap_range(
> > > >  
> > > >  	ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
> > > >  			remap_flags);
> > > > +	if (ret)
> > > > +		goto out_unlock;
> > > >  
> > > > +	if (mp->m_flags & XFS_MOUNT_WSYNC)
> > > > +		xfs_log_force_inode(dest);
> > > >  out_unlock:
> > > >  	xfs_reflink_remap_unlock(file_in, file_out);
> > > >  	if (ret)
> > > > -- 
> > > > 2.25.1
> > > > 
> > > 
> > 
>