On Sat, 8 Mar 2014, Yan, Zheng wrote:
> how about the below patch and corresponding mds change in
> https://github.com/ceph/ceph/commit/617ce6761edd7264893f3638c33fd229c71751a0
>
> Regards
> Yan, Zheng
>
> ---
> >From 0fa1971741b1d3c236ee6fa3a7feb5a74fbd7f2f Mon Sep 17 00:00:00 2001
> From: "Yan, Zheng" <[email protected]>
> Date: Thu, 6 Mar 2014 16:40:32 +0800
> Subject: [PATCH 1/3] ceph: add get_name() NFS export callback
>
> Use the newly introduced LOOKUPNAME MDS request to connect child
> inode to its parent directory.
>
> Signed-off-by: Yan, Zheng <[email protected]>
> ---
> fs/ceph/export.c | 40 ++++++++++++++++++++++++++++++++++
> fs/ceph/inode.c | 51
> +++++++++++++++++++++++++++++++++++++++++++-
> fs/ceph/strings.c | 1 +
> include/linux/ceph/ceph_fs.h | 1 +
> 4 files changed, 92 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ceph/export.c b/fs/ceph/export.c
> index 6e611e7..bf36e7f 100644
> --- a/fs/ceph/export.c
> +++ b/fs/ceph/export.c
> @@ -195,9 +195,49 @@ static struct dentry *ceph_fh_to_parent(struct
> super_block *sb,
> return dentry;
> }
>
> +static int ceph_get_name(struct dentry *parent, char *name,
> + struct dentry *child)
> +{
> + struct ceph_mds_client *mdsc;
> + struct ceph_mds_request *req;
> + int err;
> +
> + mdsc = ceph_inode_to_client(child->d_inode)->mdsc;
> + req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_LOOKUPNAME,
> + USE_ANY_MDS);
> + if (IS_ERR(req))
> + return PTR_ERR(req);
> +
> + mutex_lock(&parent->d_inode->i_mutex);
> +
> + req->r_inode = child->d_inode;
> + ihold(child->d_inode);
> + req->r_ino2 = ceph_vino(parent->d_inode);
> + req->r_locked_dir = parent->d_inode;
> + req->r_num_caps = 1;
> + err = ceph_mdsc_do_request(mdsc, NULL, req);
> +
> + mutex_unlock(&parent->d_inode->i_mutex);
> +
> + if (!err) {
> + struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
> + memcpy(name, rinfo->dname, rinfo->dname_len);
> + name[rinfo->dname_len] = 0;
> + dout("get_name %p ino %llx.%llx name %s\n",
> + child, ceph_vinop(child->d_inode), name);
One other oddity here: the MDS is returning a bunch of metadata about the
dentry, including (in most cases) a lease. The client is ignoring all of
that and only needs the name itself to feed back into exportfs. I believe
at this point that is fine: the client can forget leases at any time and
will respond to MDS revocations accordingly.
It would probably require a bit of a kludge on the MDS side to make the
reply_request() respond with the dentry name but prevent a lease from
being issued. Might be worth it though? Maybe a generic "no lease" flag
that even regular LOOKUP could use (if for some reason the client didn't
want a lease)?
This needn't hold up the other patches, but I'm curious what you think
about it.
Thanks!
sage
> + } else {
> + dout("get_name %p ino %llx.%llx err %d\n",
> + child, ceph_vinop(child->d_inode), err);
> + }
> +
> + ceph_mdsc_put_request(req);
> + return err;
> +}
> +
> const struct export_operations ceph_export_ops = {
> .encode_fh = ceph_encode_fh,
> .fh_to_dentry = ceph_fh_to_dentry,
> .fh_to_parent = ceph_fh_to_parent,
> .get_parent = ceph_get_parent,
> + .get_name = ceph_get_name,
> };
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 8bf2384..91d6c9d 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -1044,10 +1044,59 @@ int ceph_fill_trace(struct super_block *sb, struct
> ceph_mds_request *req,
> session, req->r_request_started, -1,
> &req->r_caps_reservation);
> if (err < 0)
> - return err;
> + goto done;
> } else {
> WARN_ON_ONCE(1);
> }
> +
> + if (dir && req->r_op == CEPH_MDS_OP_LOOKUPNAME) {
> + struct qstr dname;
> + struct dentry *dn, *parent;
> +
> + BUG_ON(!rinfo->head->is_target);
> + BUG_ON(req->r_dentry);
> +
> + parent = d_find_any_alias(dir);
> + BUG_ON(!parent);
> +
> + dname.name = rinfo->dname;
> + dname.len = rinfo->dname_len;
> + dname.hash = full_name_hash(dname.name, dname.len);
> + vino.ino = le64_to_cpu(rinfo->targeti.in->ino);
> + vino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
> +retry_lookup:
> + dn = d_lookup(parent, &dname);
> + dout("d_lookup on parent=%p name=%.*s got %p\n",
> + parent, dname.len, dname.name, dn);
> +
> + if (!dn) {
> + dn = d_alloc(parent, &dname);
> + dout("d_alloc %p '%.*s' = %p\n", parent,
> + dname.len, dname.name, dn);
> + if (dn == NULL) {
> + dput(parent);
> + err = -ENOMEM;
> + goto done;
> + }
> + err = ceph_init_dentry(dn);
> + if (err < 0) {
> + dput(dn);
> + dput(parent);
> + goto done;
> + }
> + } else if (dn->d_inode &&
> + (ceph_ino(dn->d_inode) != vino.ino ||
> + ceph_snap(dn->d_inode) != vino.snap)) {
> + dout(" dn %p points to wrong inode %p\n",
> + dn, dn->d_inode);
> + d_delete(dn);
> + dput(dn);
> + goto retry_lookup;
> + }
> +
> + req->r_dentry = dn;
> + dput(parent);
> + }
> }
>
> if (rinfo->head->is_target) {
> diff --git a/fs/ceph/strings.c b/fs/ceph/strings.c
> index 4440f447..51cc23e 100644
> --- a/fs/ceph/strings.c
> +++ b/fs/ceph/strings.c
> @@ -54,6 +54,7 @@ const char *ceph_mds_op_name(int op)
> case CEPH_MDS_OP_LOOKUPHASH: return "lookuphash";
> case CEPH_MDS_OP_LOOKUPPARENT: return "lookupparent";
> case CEPH_MDS_OP_LOOKUPINO: return "lookupino";
> + case CEPH_MDS_OP_LOOKUPNAME: return "lookupname";
> case CEPH_MDS_OP_GETATTR: return "getattr";
> case CEPH_MDS_OP_SETXATTR: return "setxattr";
> case CEPH_MDS_OP_SETATTR: return "setattr";
> diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
> index 25bfb0e..35f345f 100644
> --- a/include/linux/ceph/ceph_fs.h
> +++ b/include/linux/ceph/ceph_fs.h
> @@ -332,6 +332,7 @@ enum {
> CEPH_MDS_OP_LOOKUPHASH = 0x00102,
> CEPH_MDS_OP_LOOKUPPARENT = 0x00103,
> CEPH_MDS_OP_LOOKUPINO = 0x00104,
> + CEPH_MDS_OP_LOOKUPNAME = 0x00105,
>
> CEPH_MDS_OP_SETXATTR = 0x01105,
> CEPH_MDS_OP_RMXATTR = 0x01106,
> --
> 1.8.5.3
>
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