diff mbox series

[v6,3/7] tmpfs: bump the mtime/ctime/iversion when page becomes writeable

Message ID 20230725-mgctime-v6-3-a794c2b7abca@kernel.org (mailing list archive)
State New
Headers show
Series fs: implement multigrain timestamps | expand

Commit Message

Jeff Layton July 25, 2023, 2:58 p.m. UTC
Most filesystems that use the pagecache will update the mtime, ctime,
and change attribute when a page becomes writeable. Add a page_mkwrite
operation for tmpfs and just use it to bump the mtime, ctime and change
attribute.

This fixes xfstest generic/080 on tmpfs.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 mm/shmem.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Comments

Hugh Dickins July 26, 2023, 1:39 a.m. UTC | #1
On Tue, 25 Jul 2023, Jeff Layton wrote:

> Most filesystems that use the pagecache will update the mtime, ctime,
> and change attribute when a page becomes writeable. Add a page_mkwrite
> operation for tmpfs and just use it to bump the mtime, ctime and change
> attribute.
> 
> This fixes xfstest generic/080 on tmpfs.

Huh.  I didn't notice when this one crept into the multigrain series.

I'm inclined to NAK this patch: at the very least, it does not belong
in the series, but should be discussed separately.

Yes, tmpfs does not and never has used page_mkwrite, and gains some
performance advantage from that.  Nobody has ever asked for this
change before, or not that I recall.

Please drop it from the series: and if you feel strongly, or know
strong reasons why tmpfs suddenly needs to use page_mkwrite now,
please argue them separately.  To pass generic/080 is not enough.

Thanks,
Hugh

> 
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  mm/shmem.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/mm/shmem.c b/mm/shmem.c
> index b154af49d2df..654d9a585820 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2169,6 +2169,16 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
>  	return ret;
>  }
>  
> +static vm_fault_t shmem_page_mkwrite(struct vm_fault *vmf)
> +{
> +	struct vm_area_struct *vma = vmf->vma;
> +	struct inode *inode = file_inode(vma->vm_file);
> +
> +	file_update_time(vma->vm_file);
> +	inode_inc_iversion(inode);
> +	return 0;
> +}
> +
>  unsigned long shmem_get_unmapped_area(struct file *file,
>  				      unsigned long uaddr, unsigned long len,
>  				      unsigned long pgoff, unsigned long flags)
> @@ -4210,6 +4220,7 @@ static const struct super_operations shmem_ops = {
>  
>  static const struct vm_operations_struct shmem_vm_ops = {
>  	.fault		= shmem_fault,
> +	.page_mkwrite	= shmem_page_mkwrite,
>  	.map_pages	= filemap_map_pages,
>  #ifdef CONFIG_NUMA
>  	.set_policy     = shmem_set_policy,
> @@ -4219,6 +4230,7 @@ static const struct vm_operations_struct shmem_vm_ops = {
>  
>  static const struct vm_operations_struct shmem_anon_vm_ops = {
>  	.fault		= shmem_fault,
> +	.page_mkwrite	= shmem_page_mkwrite,
>  	.map_pages	= filemap_map_pages,
>  #ifdef CONFIG_NUMA
>  	.set_policy     = shmem_set_policy,
> 
> -- 
> 2.41.0
Jeff Layton July 26, 2023, 10:26 a.m. UTC | #2
On Tue, 2023-07-25 at 18:39 -0700, Hugh Dickins wrote:
> On Tue, 25 Jul 2023, Jeff Layton wrote:
> 
> > Most filesystems that use the pagecache will update the mtime, ctime,
> > and change attribute when a page becomes writeable. Add a page_mkwrite
> > operation for tmpfs and just use it to bump the mtime, ctime and change
> > attribute.
> > 
> > This fixes xfstest generic/080 on tmpfs.
> 
> Huh.  I didn't notice when this one crept into the multigrain series.
> 
> I'm inclined to NAK this patch: at the very least, it does not belong
> in the series, but should be discussed separately.
> 
> Yes, tmpfs does not and never has used page_mkwrite, and gains some
> performance advantage from that.  Nobody has ever asked for this
> change before, or not that I recall.
> 
> Please drop it from the series: and if you feel strongly, or know
> strong reasons why tmpfs suddenly needs to use page_mkwrite now,
> please argue them separately.  To pass generic/080 is not enough.
> 
> Thanks,
> Hugh
> 

Dropped.

This was just something I noticed while testing this series. It stood
out since I was particularly watching for timestamp-related test
failures. I don't feel terribly strongly about it.

Thanks!

> > 
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >  mm/shmem.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/mm/shmem.c b/mm/shmem.c
> > index b154af49d2df..654d9a585820 100644
> > --- a/mm/shmem.c
> > +++ b/mm/shmem.c
> > @@ -2169,6 +2169,16 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
> >  	return ret;
> >  }
> >  
> > +static vm_fault_t shmem_page_mkwrite(struct vm_fault *vmf)
> > +{
> > +	struct vm_area_struct *vma = vmf->vma;
> > +	struct inode *inode = file_inode(vma->vm_file);
> > +
> > +	file_update_time(vma->vm_file);
> > +	inode_inc_iversion(inode);
> > +	return 0;
> > +}
> > +
> >  unsigned long shmem_get_unmapped_area(struct file *file,
> >  				      unsigned long uaddr, unsigned long len,
> >  				      unsigned long pgoff, unsigned long flags)
> > @@ -4210,6 +4220,7 @@ static const struct super_operations shmem_ops = {
> >  
> >  static const struct vm_operations_struct shmem_vm_ops = {
> >  	.fault		= shmem_fault,
> > +	.page_mkwrite	= shmem_page_mkwrite,
> >  	.map_pages	= filemap_map_pages,
> >  #ifdef CONFIG_NUMA
> >  	.set_policy     = shmem_set_policy,
> > @@ -4219,6 +4230,7 @@ static const struct vm_operations_struct shmem_vm_ops = {
> >  
> >  static const struct vm_operations_struct shmem_anon_vm_ops = {
> >  	.fault		= shmem_fault,
> > +	.page_mkwrite	= shmem_page_mkwrite,
> >  	.map_pages	= filemap_map_pages,
> >  #ifdef CONFIG_NUMA
> >  	.set_policy     = shmem_set_policy,
> > 
> > -- 
> > 2.41.0
diff mbox series

Patch

diff --git a/mm/shmem.c b/mm/shmem.c
index b154af49d2df..654d9a585820 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2169,6 +2169,16 @@  static vm_fault_t shmem_fault(struct vm_fault *vmf)
 	return ret;
 }
 
+static vm_fault_t shmem_page_mkwrite(struct vm_fault *vmf)
+{
+	struct vm_area_struct *vma = vmf->vma;
+	struct inode *inode = file_inode(vma->vm_file);
+
+	file_update_time(vma->vm_file);
+	inode_inc_iversion(inode);
+	return 0;
+}
+
 unsigned long shmem_get_unmapped_area(struct file *file,
 				      unsigned long uaddr, unsigned long len,
 				      unsigned long pgoff, unsigned long flags)
@@ -4210,6 +4220,7 @@  static const struct super_operations shmem_ops = {
 
 static const struct vm_operations_struct shmem_vm_ops = {
 	.fault		= shmem_fault,
+	.page_mkwrite	= shmem_page_mkwrite,
 	.map_pages	= filemap_map_pages,
 #ifdef CONFIG_NUMA
 	.set_policy     = shmem_set_policy,
@@ -4219,6 +4230,7 @@  static const struct vm_operations_struct shmem_vm_ops = {
 
 static const struct vm_operations_struct shmem_anon_vm_ops = {
 	.fault		= shmem_fault,
+	.page_mkwrite	= shmem_page_mkwrite,
 	.map_pages	= filemap_map_pages,
 #ifdef CONFIG_NUMA
 	.set_policy     = shmem_set_policy,