On 03/10/2014 09:49 AM, Sage Weil wrote:
> 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.
>
the nfsd does a dentry lookup after it has got the name. the lease can avoid
sending another 'lookup' request to the MDS.
Regards
Yan, Zheng
>
>
>> + } 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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>>
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