On 03/10/2014 12:12 PM, Sage Weil wrote: > On Mon, 10 Mar 2014, Yan, Zheng wrote: >> 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" <zheng.z.yan@xxxxxxxxx> >>>> 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 <zheng.z.yan@xxxxxxxxx> >>>> --- >>>> 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. > > For that to work, I think we need to preallocate the dentry and set > req->r_dentry. The ceph_fill_trace() code, in fact, looks like it will > BUG out if it gets a reply with a dentry but the request r_dentry isn't > set (we should probably fix that too). > > In any case, that seems tricky because we don't know the name ahead of > time, so it would need to have its own code path on reply to allocate the > dentry of the proper name. Given that this is only used in rare NFS > re-export corner cases, my inclination is to not bother optimizing? > > sage > > >> >> 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; req->r_dentry is set here. is there anything I'm missing? Regards Yan, Zheng >>>> + 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 >>>> >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>>> >> >> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
