Re: [PATCH v9 8/8] xfs: Add dax dedupe support
On Thu, Sep 16, 2021 at 12:01:18PM +0800, Shiyang Ruan wrote:
>
>
> On 2021/9/16 8:30, Darrick J. Wong wrote:
> > On Wed, Sep 15, 2021 at 06:45:01PM +0800, Shiyang Ruan wrote:
> > > Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files
> > > who are going to be deduped. After that, call compare range function
> > > only when files are both DAX or not.
> > >
> > > Signed-off-by: Shiyang Ruan
> > > Reviewed-by: Darrick J. Wong
> > > Reviewed-by: Christoph Hellwig
> > > ---
> > > fs/xfs/xfs_file.c| 2 +-
> > > fs/xfs/xfs_inode.c | 80 +---
> > > fs/xfs/xfs_inode.h | 1 +
> > > fs/xfs/xfs_reflink.c | 4 +--
> > > 4 files changed, 80 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> > > index 2ef1930374d2..c3061723613c 100644
> > > --- a/fs/xfs/xfs_file.c
> > > +++ b/fs/xfs/xfs_file.c
> > > @@ -846,7 +846,7 @@ xfs_wait_dax_page(
> > > xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
> > > }
> > > -static int
> > > +int
> > > xfs_break_dax_layouts(
> > > struct inode*inode,
> > > bool*retry)
> > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> > > index a4f6f034fb81..bdc084cdbf46 100644
> > > --- a/fs/xfs/xfs_inode.c
> > > +++ b/fs/xfs/xfs_inode.c
> > > @@ -3790,6 +3790,61 @@ xfs_iolock_two_inodes_and_break_layout(
> > > return 0;
> > > }
> > > +static int
> > > +xfs_mmaplock_two_inodes_and_break_dax_layout(
> > > + struct xfs_inode*ip1,
> > > + struct xfs_inode*ip2)
> > > +{
> > > + int error, attempts = 0;
> > > + boolretry;
> > > + struct page *page;
> > > + struct xfs_log_item *lp;
> > > +
> > > + if (ip1->i_ino > ip2->i_ino)
> > > + swap(ip1, ip2);
> > > +
> > > +again:
> > > + retry = false;
> > > + /* Lock the first inode */
> > > + xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);
> > > + error = xfs_break_dax_layouts(VFS_I(ip1), );
> > > + if (error || retry) {
> > > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> > > + if (error == 0 && retry)
> > > + goto again;
> > > + return error;
> > > + }
> > > +
> > > + if (ip1 == ip2)
> > > + return 0;
> > > +
> > > + /* Nested lock the second inode */
> > > + lp = >i_itemp->ili_item;
> > > + if (lp && test_bit(XFS_LI_IN_AIL, >li_flags)) {
> > > + if (!xfs_ilock_nowait(ip2,
> > > + xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1))) {
> > > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> > > + if ((++attempts % 5) == 0)
> > > + delay(1); /* Don't just spin the CPU */
> > > + goto again;
> > > + }
> >
> > I suspect we don't need this part for grabbing the MMAPLOCK^W pagecache
> > invalidatelock. The AIL only grabs the ILOCK, never the IOLOCK or the
> > MMAPLOCK.
>
> Maybe I have misunderstood this part.
>
> What I want is to lock the two inode nestedly. This code is copied from
> xfs_lock_two_inodes(), which checks this AIL during locking two inode with
> each of the three kinds of locks.
It's totally reasonable to copy-paste the function you want and
change it as needed...
> But I also found the recent merged function: filemap_invalidate_lock_two()
> just locks two inode directly without checking AIL. So, I am not if the AIL
> check is needed in this case.
...especially when even the maintainer is only 99% sure that the AIL
checking chunk here can be removed. Anyone else have an opinion?
--D
> >
> > > + } else
> > > + xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1));
> > > + /*
> > > + * We cannot use xfs_break_dax_layouts() directly here because it may
> > > + * need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable
> > > + * for this nested lock case.
> > > + */
> > > + page = dax_layout_busy_page(VFS_I(ip2)->i_mapping);
> > > + if (page && page_ref_count(page) != 1) {
> >
> > Do you think the patch "ext4/xfs: add page refcount helper" would be a
> > good cleanup to head this series?
> >
> > https://lore.kernel.org/linux-xfs/20210913161604.31981-1-alex.sie...@amd.com/T/#m59cf7cd5c0d521ad487fa3a15d31c3865db88bdf
>
> Got it.
>
>
> --
> Thanks,
> Ruan
>
> >
> > The rest of the logic looks ok.
> >
> > --D
> >
> > > + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
> > > + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> > > + goto again;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > /*
> > >* Lock two inodes so that userspace cannot initiate I/O via file
> > > syscalls or
> > >* mmap activity.
> > > @@ -3804,8 +3859,19 @@ xfs_ilock2_io_mmap(
> > > ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1),
> > > VFS_I(ip2));
> > > if (ret)
> > > return ret;
> > > - filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
> > > -
Re: [PATCH v9 8/8] xfs: Add dax dedupe support
On 2021/9/16 8:30, Darrick J. Wong wrote:
On Wed, Sep 15, 2021 at 06:45:01PM +0800, Shiyang Ruan wrote:
Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files
who are going to be deduped. After that, call compare range function
only when files are both DAX or not.
Signed-off-by: Shiyang Ruan
Reviewed-by: Darrick J. Wong
Reviewed-by: Christoph Hellwig
---
fs/xfs/xfs_file.c| 2 +-
fs/xfs/xfs_inode.c | 80 +---
fs/xfs/xfs_inode.h | 1 +
fs/xfs/xfs_reflink.c | 4 +--
4 files changed, 80 insertions(+), 7 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 2ef1930374d2..c3061723613c 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -846,7 +846,7 @@ xfs_wait_dax_page(
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
}
-static int
+int
xfs_break_dax_layouts(
struct inode*inode,
bool*retry)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index a4f6f034fb81..bdc084cdbf46 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3790,6 +3790,61 @@ xfs_iolock_two_inodes_and_break_layout(
return 0;
}
+static int
+xfs_mmaplock_two_inodes_and_break_dax_layout(
+ struct xfs_inode*ip1,
+ struct xfs_inode*ip2)
+{
+ int error, attempts = 0;
+ boolretry;
+ struct page *page;
+ struct xfs_log_item *lp;
+
+ if (ip1->i_ino > ip2->i_ino)
+ swap(ip1, ip2);
+
+again:
+ retry = false;
+ /* Lock the first inode */
+ xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);
+ error = xfs_break_dax_layouts(VFS_I(ip1), );
+ if (error || retry) {
+ xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+ if (error == 0 && retry)
+ goto again;
+ return error;
+ }
+
+ if (ip1 == ip2)
+ return 0;
+
+ /* Nested lock the second inode */
+ lp = >i_itemp->ili_item;
+ if (lp && test_bit(XFS_LI_IN_AIL, >li_flags)) {
+ if (!xfs_ilock_nowait(ip2,
+ xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1))) {
+ xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+ if ((++attempts % 5) == 0)
+ delay(1); /* Don't just spin the CPU */
+ goto again;
+ }
I suspect we don't need this part for grabbing the MMAPLOCK^W pagecache
invalidatelock. The AIL only grabs the ILOCK, never the IOLOCK or the
MMAPLOCK.
Maybe I have misunderstood this part.
What I want is to lock the two inode nestedly. This code is copied from
xfs_lock_two_inodes(), which checks this AIL during locking two inode
with each of the three kinds of locks.
But I also found the recent merged function:
filemap_invalidate_lock_two() just locks two inode directly without
checking AIL. So, I am not if the AIL check is needed in this case.
+ } else
+ xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1));
+ /*
+* We cannot use xfs_break_dax_layouts() directly here because it may
+* need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable
+* for this nested lock case.
+*/
+ page = dax_layout_busy_page(VFS_I(ip2)->i_mapping);
+ if (page && page_ref_count(page) != 1) {
Do you think the patch "ext4/xfs: add page refcount helper" would be a
good cleanup to head this series?
https://lore.kernel.org/linux-xfs/20210913161604.31981-1-alex.sie...@amd.com/T/#m59cf7cd5c0d521ad487fa3a15d31c3865db88bdf
Got it.
--
Thanks,
Ruan
The rest of the logic looks ok.
--D
+ xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
+ xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
+ goto again;
+ }
+
+ return 0;
+}
+
/*
* Lock two inodes so that userspace cannot initiate I/O via file syscalls or
* mmap activity.
@@ -3804,8 +3859,19 @@ xfs_ilock2_io_mmap(
ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
if (ret)
return ret;
- filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
- VFS_I(ip2)->i_mapping);
+
+ if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) {
+ ret = xfs_mmaplock_two_inodes_and_break_dax_layout(ip1, ip2);
+ if (ret) {
+ inode_unlock(VFS_I(ip2));
+ if (ip1 != ip2)
+ inode_unlock(VFS_I(ip1));
+ return ret;
+ }
+ } else
+ filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
+ VFS_I(ip2)->i_mapping);
+
return 0;
}
@@ -3815,8 +3881,14 @@ xfs_iunlock2_io_mmap(
struct xfs_inode*ip1,
struct xfs_inode*ip2)
{
-
Re: [PATCH v9 8/8] xfs: Add dax dedupe support
On Wed, Sep 15, 2021 at 06:45:01PM +0800, Shiyang Ruan wrote:
> Introduce xfs_mmaplock_two_inodes_and_break_dax_layout() for dax files
> who are going to be deduped. After that, call compare range function
> only when files are both DAX or not.
>
> Signed-off-by: Shiyang Ruan
> Reviewed-by: Darrick J. Wong
> Reviewed-by: Christoph Hellwig
> ---
> fs/xfs/xfs_file.c| 2 +-
> fs/xfs/xfs_inode.c | 80 +---
> fs/xfs/xfs_inode.h | 1 +
> fs/xfs/xfs_reflink.c | 4 +--
> 4 files changed, 80 insertions(+), 7 deletions(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 2ef1930374d2..c3061723613c 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -846,7 +846,7 @@ xfs_wait_dax_page(
> xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
> }
>
> -static int
> +int
> xfs_break_dax_layouts(
> struct inode*inode,
> bool*retry)
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index a4f6f034fb81..bdc084cdbf46 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -3790,6 +3790,61 @@ xfs_iolock_two_inodes_and_break_layout(
> return 0;
> }
>
> +static int
> +xfs_mmaplock_two_inodes_and_break_dax_layout(
> + struct xfs_inode*ip1,
> + struct xfs_inode*ip2)
> +{
> + int error, attempts = 0;
> + boolretry;
> + struct page *page;
> + struct xfs_log_item *lp;
> +
> + if (ip1->i_ino > ip2->i_ino)
> + swap(ip1, ip2);
> +
> +again:
> + retry = false;
> + /* Lock the first inode */
> + xfs_ilock(ip1, XFS_MMAPLOCK_EXCL);
> + error = xfs_break_dax_layouts(VFS_I(ip1), );
> + if (error || retry) {
> + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> + if (error == 0 && retry)
> + goto again;
> + return error;
> + }
> +
> + if (ip1 == ip2)
> + return 0;
> +
> + /* Nested lock the second inode */
> + lp = >i_itemp->ili_item;
> + if (lp && test_bit(XFS_LI_IN_AIL, >li_flags)) {
> + if (!xfs_ilock_nowait(ip2,
> + xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1))) {
> + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> + if ((++attempts % 5) == 0)
> + delay(1); /* Don't just spin the CPU */
> + goto again;
> + }
I suspect we don't need this part for grabbing the MMAPLOCK^W pagecache
invalidatelock. The AIL only grabs the ILOCK, never the IOLOCK or the
MMAPLOCK.
> + } else
> + xfs_ilock(ip2, xfs_lock_inumorder(XFS_MMAPLOCK_EXCL, 1));
> + /*
> + * We cannot use xfs_break_dax_layouts() directly here because it may
> + * need to unlock & lock the XFS_MMAPLOCK_EXCL which is not suitable
> + * for this nested lock case.
> + */
> + page = dax_layout_busy_page(VFS_I(ip2)->i_mapping);
> + if (page && page_ref_count(page) != 1) {
Do you think the patch "ext4/xfs: add page refcount helper" would be a
good cleanup to head this series?
https://lore.kernel.org/linux-xfs/20210913161604.31981-1-alex.sie...@amd.com/T/#m59cf7cd5c0d521ad487fa3a15d31c3865db88bdf
The rest of the logic looks ok.
--D
> + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
> + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> + goto again;
> + }
> +
> + return 0;
> +}
> +
> /*
> * Lock two inodes so that userspace cannot initiate I/O via file syscalls or
> * mmap activity.
> @@ -3804,8 +3859,19 @@ xfs_ilock2_io_mmap(
> ret = xfs_iolock_two_inodes_and_break_layout(VFS_I(ip1), VFS_I(ip2));
> if (ret)
> return ret;
> - filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
> - VFS_I(ip2)->i_mapping);
> +
> + if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) {
> + ret = xfs_mmaplock_two_inodes_and_break_dax_layout(ip1, ip2);
> + if (ret) {
> + inode_unlock(VFS_I(ip2));
> + if (ip1 != ip2)
> + inode_unlock(VFS_I(ip1));
> + return ret;
> + }
> + } else
> + filemap_invalidate_lock_two(VFS_I(ip1)->i_mapping,
> + VFS_I(ip2)->i_mapping);
> +
> return 0;
> }
>
> @@ -3815,8 +3881,14 @@ xfs_iunlock2_io_mmap(
> struct xfs_inode*ip1,
> struct xfs_inode*ip2)
> {
> - filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping,
> - VFS_I(ip2)->i_mapping);
> + if (IS_DAX(VFS_I(ip1)) && IS_DAX(VFS_I(ip2))) {
> + xfs_iunlock(ip2, XFS_MMAPLOCK_EXCL);
> + if (ip1 != ip2)
> + xfs_iunlock(ip1, XFS_MMAPLOCK_EXCL);
> + } else
> + filemap_invalidate_unlock_two(VFS_I(ip1)->i_mapping,
> +
