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