[PATCH] ceph: set pool_ns in new inode layout for async creates

[PATCH] ceph: set pool_ns in new inode layout for async creates

[Jeff Layton]

Dan reported that he was unable to write to files that had been
asynchronously created when the client's OSD caps are restricted to a
particular namespace.

The issue is that the layout for the new inode is only partially being
filled. Ensure that we populate the pool_ns_data and pool_ns_len in the
iinfo before calling ceph_fill_inode.

Reported-by: Dan van der Ster <dan@vanderster.com>
Fixes: 9a8d03ca2e2c ("ceph: attempt to do async create when possible")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/file.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index cbe4d5a5cde5..efea321ff643 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -599,6 +599,7 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 	struct ceph_inode_info *ci = ceph_inode(dir);
 	struct inode *inode;
 	struct timespec64 now;
+	struct ceph_string *pool_ns;
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_vino vino = { .ino = req->r_deleg_ino,
 				  .snap = CEPH_NOSNAP };
@@ -648,11 +649,17 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 	in.max_size = cpu_to_le64(lo->stripe_unit);
 
 	ceph_file_layout_to_legacy(lo, &in.layout);
+	pool_ns = ceph_try_get_string(lo->pool_ns);
+	if (pool_ns) {
+		iinfo.pool_ns_len = pool_ns->len;
+		iinfo.pool_ns_data = pool_ns->str;
+	}
 
 	down_read(&mdsc->snap_rwsem);
 	ret = ceph_fill_inode(inode, NULL, &iinfo, NULL, req->r_session,
 			      req->r_fmode, NULL);
 	up_read(&mdsc->snap_rwsem);
+	ceph_put_string(pool_ns);
 	if (ret) {
 		dout("%s failed to fill inode: %d\n", __func__, ret);
 		ceph_dir_clear_complete(dir);
-- 
2.34.1

Re: [PATCH] ceph: set pool_ns in new inode layout for async creates

[Ilya Dryomov]

On Tue, Jan 25, 2022 at 10:10 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> Dan reported that he was unable to write to files that had been
> asynchronously created when the client's OSD caps are restricted to a
> particular namespace.
>
> The issue is that the layout for the new inode is only partially being
> filled. Ensure that we populate the pool_ns_data and pool_ns_len in the
> iinfo before calling ceph_fill_inode.
>
> Reported-by: Dan van der Ster <dan@vanderster.com>
> Fixes: 9a8d03ca2e2c ("ceph: attempt to do async create when possible")
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>  fs/ceph/file.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index cbe4d5a5cde5..efea321ff643 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -599,6 +599,7 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
>         struct ceph_inode_info *ci = ceph_inode(dir);
>         struct inode *inode;
>         struct timespec64 now;
> +       struct ceph_string *pool_ns;
>         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
>         struct ceph_vino vino = { .ino = req->r_deleg_ino,
>                                   .snap = CEPH_NOSNAP };
> @@ -648,11 +649,17 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
>         in.max_size = cpu_to_le64(lo->stripe_unit);
>
>         ceph_file_layout_to_legacy(lo, &in.layout);
> +       pool_ns = ceph_try_get_string(lo->pool_ns);
> +       if (pool_ns) {
> +               iinfo.pool_ns_len = pool_ns->len;
> +               iinfo.pool_ns_data = pool_ns->str;
> +       }

Considering that we have a reference from try_prep_async_create(), do
we actually need to bother with ceph_try_get_string() here?

Thanks,

                Ilya

Re: [PATCH] ceph: set pool_ns in new inode layout for async creates

[Jeff Layton]

On Wed, 2022-01-26 at 17:23 +0100, Ilya Dryomov wrote:
> On Tue, Jan 25, 2022 at 10:10 PM Jeff Layton <jlayton@kernel.org> wrote:
> > 
> > Dan reported that he was unable to write to files that had been
> > asynchronously created when the client's OSD caps are restricted to a
> > particular namespace.
> > 
> > The issue is that the layout for the new inode is only partially being
> > filled. Ensure that we populate the pool_ns_data and pool_ns_len in the
> > iinfo before calling ceph_fill_inode.
> > 
> > Reported-by: Dan van der Ster <dan@vanderster.com>
> > Fixes: 9a8d03ca2e2c ("ceph: attempt to do async create when possible")
> > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > ---
> >  fs/ceph/file.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > index cbe4d5a5cde5..efea321ff643 100644
> > --- a/fs/ceph/file.c
> > +++ b/fs/ceph/file.c
> > @@ -599,6 +599,7 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
> >         struct ceph_inode_info *ci = ceph_inode(dir);
> >         struct inode *inode;
> >         struct timespec64 now;
> > +       struct ceph_string *pool_ns;
> >         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> >         struct ceph_vino vino = { .ino = req->r_deleg_ino,
> >                                   .snap = CEPH_NOSNAP };
> > @@ -648,11 +649,17 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
> >         in.max_size = cpu_to_le64(lo->stripe_unit);
> > 
> >         ceph_file_layout_to_legacy(lo, &in.layout);
> > +       pool_ns = ceph_try_get_string(lo->pool_ns);
> > +       if (pool_ns) {
> > +               iinfo.pool_ns_len = pool_ns->len;
> > +               iinfo.pool_ns_data = pool_ns->str;
> > +       }
> 
> Considering that we have a reference from try_prep_async_create(), do
> we actually need to bother with ceph_try_get_string() here?
> 

Technically, no. We could just do a rcu_dereference_protected there
since we know that lo is private and can't change. Want me to send a v2?
-- 
Jeff Layton <jlayton@kernel.org>

Re: [PATCH] ceph: set pool_ns in new inode layout for async creates

[Ilya Dryomov]

On Wed, Jan 26, 2022 at 5:34 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> On Wed, 2022-01-26 at 17:23 +0100, Ilya Dryomov wrote:
> > On Tue, Jan 25, 2022 at 10:10 PM Jeff Layton <jlayton@kernel.org> wrote:
> > >
> > > Dan reported that he was unable to write to files that had been
> > > asynchronously created when the client's OSD caps are restricted to a
> > > particular namespace.
> > >
> > > The issue is that the layout for the new inode is only partially being
> > > filled. Ensure that we populate the pool_ns_data and pool_ns_len in the
> > > iinfo before calling ceph_fill_inode.
> > >
> > > Reported-by: Dan van der Ster <dan@vanderster.com>
> > > Fixes: 9a8d03ca2e2c ("ceph: attempt to do async create when possible")
> > > Signed-off-by: Jeff Layton <jlayton@kernel.org>
> > > ---
> > >  fs/ceph/file.c | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > >
> > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> > > index cbe4d5a5cde5..efea321ff643 100644
> > > --- a/fs/ceph/file.c
> > > +++ b/fs/ceph/file.c
> > > @@ -599,6 +599,7 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
> > >         struct ceph_inode_info *ci = ceph_inode(dir);
> > >         struct inode *inode;
> > >         struct timespec64 now;
> > > +       struct ceph_string *pool_ns;
> > >         struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
> > >         struct ceph_vino vino = { .ino = req->r_deleg_ino,
> > >                                   .snap = CEPH_NOSNAP };
> > > @@ -648,11 +649,17 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
> > >         in.max_size = cpu_to_le64(lo->stripe_unit);
> > >
> > >         ceph_file_layout_to_legacy(lo, &in.layout);
> > > +       pool_ns = ceph_try_get_string(lo->pool_ns);
> > > +       if (pool_ns) {
> > > +               iinfo.pool_ns_len = pool_ns->len;
> > > +               iinfo.pool_ns_data = pool_ns->str;
> > > +       }
> >
> > Considering that we have a reference from try_prep_async_create(), do
> > we actually need to bother with ceph_try_get_string() here?
> >
>
> Technically, no. We could just do a rcu_dereference_protected there
> since we know that lo is private and can't change. Want me to send a v2?

Yeah, let's not do the reference dance when it isn't needed.

I'd probably use rcu_dereference_raw() to avoid having to think about
omitted READ_ONCE (even if the reasoning is trivial), but up to you.

Thanks,

                Ilya