On Wed, 2020-12-16 at 21:59 +0100, Ilya Dryomov wrote:
> On Wed, Dec 16, 2020 at 9:16 PM Ilya Dryomov <idryomov@xxxxxxxxx> wrote:
> >
> > On Wed, Dec 16, 2020 at 8:50 PM Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> > >
> > > When we added the btime feature in mainline ceph, we had to extend
> > > struct ceph_mds_request_args so that it could be set. Implement the same
> > > in the kernel client.
> > >
> > > Rename ceph_mds_request_head with a _old extension, and a union
> > > ceph_mds_request_args_ext to allow for the extended size of the new
> > > header format.
> > >
> > > Add the appropriate code to handle both formats in struct
> > > create_request_message and key the behavior on whether the peer supports
> > > CEPH_FEATURE_FS_BTIME.
> > >
> > > The gid_list field in the payload is now populated from the saved
> > > credential. For now, we don't add any support for setting the btime via
> > > setattr, but this does enable us to add that in the future.
> > >
> > > [ idryomov: break unnecessarily long lines ]
> > >
> > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > > ---
> > > fs/ceph/mds_client.c | 101 ++++++++++++++++++++++++++---------
> > > include/linux/ceph/ceph_fs.h | 32 ++++++++++-
> > > 2 files changed, 108 insertions(+), 25 deletions(-)
> > >
> > > v2: fix encoding of unsafe request resends
> > > add encode_payload_tail helper
> > > rework find_old_request_head to take a "legacy" flag argument
> > >
> > > Ilya,
> > >
> > > I'll go ahead and merge this into testing, but your call on whether we
> > > should take this for v5.11, or wait for v5.12. We don't have anything
> > > blocked on this just yet.
> > >
> > > I dropped your SoB and Xiubo Reviewed-by tags as well, as the patch is
> > > a bit different from the original.
> > >
> > > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > > index 0ff76f21466a..cd0cc5d8c4f0 100644
> > > --- a/fs/ceph/mds_client.c
> > > +++ b/fs/ceph/mds_client.c
> > > @@ -2475,15 +2475,46 @@ static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
> > > return r;
> > > }
> > >
> > > +static struct ceph_mds_request_head_old *
> > > +find_old_request_head(void *p, bool legacy)
> > > +{
> > > + struct ceph_mds_request_head *new_head;
> > > +
> > > + if (legacy)
> > > + return (struct ceph_mds_request_head_old *)p;
> > > + new_head = (struct ceph_mds_request_head *)p;
> > > + return (struct ceph_mds_request_head_old *)&new_head->oldest_client_tid;
> > > +}
> > > +
> > > +static void encode_payload_tail(void **p, struct ceph_mds_request *req, bool legacy)
> > > +{
> > > + struct ceph_timespec ts;
> > > +
> > > + ceph_encode_timespec64(&ts, &req->r_stamp);
> > > + ceph_encode_copy(p, &ts, sizeof(ts));
> > > +
> > > + /* gid list */
> > > + if (!legacy) {
> > > + int i;
> > > +
> > > + ceph_encode_32(p, req->r_cred->group_info->ngroups);
> > > + for (i = 0; i < req->r_cred->group_info->ngroups; i++)
> > > + ceph_encode_64(p, from_kgid(&init_user_ns,
> > > + req->r_cred->group_info->gid[i]));
> > > + }
> > > +}
> > > +
> > > /*
> > > * called under mdsc->mutex
> > > */
> > > -static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
> > > +static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
> > > struct ceph_mds_request *req,
> > > - int mds, bool drop_cap_releases)
> > > + bool drop_cap_releases)
> > > {
> > > + int mds = session->s_mds;
> > > + struct ceph_mds_client *mdsc = session->s_mdsc;
> > > struct ceph_msg *msg;
> > > - struct ceph_mds_request_head *head;
> > > + struct ceph_mds_request_head_old *head;
> > > const char *path1 = NULL;
> > > const char *path2 = NULL;
> > > u64 ino1 = 0, ino2 = 0;
> > > @@ -2493,6 +2524,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
> > > u16 releases;
> > > void *p, *end;
> > > int ret;
> > > + bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> > >
> > > ret = set_request_path_attr(req->r_inode, req->r_dentry,
> > > req->r_parent, req->r_path1, req->r_ino1.ino,
> > > @@ -2514,14 +2546,23 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
> > > goto out_free1;
> > > }
> > >
> > > - len = sizeof(*head) +
> > > - pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
> > > + if (legacy) {
> > > + /* Old style */
> > > + len = sizeof(*head);
> > > + } else {
> > > + /* New style: add gid_list and any later fields */
> > > + len = sizeof(struct ceph_mds_request_head) + sizeof(u32) +
> > > + (sizeof(u64) * req->r_cred->group_info->ngroups);
> > > + }
> > > +
> > > + len += pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
> > > sizeof(struct ceph_timespec);
> > >
> > > /* calculate (max) length for cap releases */
> > > len += sizeof(struct ceph_mds_request_release) *
> > > (!!req->r_inode_drop + !!req->r_dentry_drop +
> > > !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
> > > +
> > > if (req->r_dentry_drop)
> > > len += pathlen1;
> > > if (req->r_old_dentry_drop)
> > > @@ -2533,11 +2574,25 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
> > > goto out_free2;
> > > }
> > >
> > > - msg->hdr.version = cpu_to_le16(3);
> > > msg->hdr.tid = cpu_to_le64(req->r_tid);
> > >
> > > - head = msg->front.iov_base;
> > > - p = msg->front.iov_base + sizeof(*head);
> > > + /*
> > > + * The old ceph_mds_request_header didn't contain a version field, and
> > > + * one was added when we moved the message version from 3->4.
> > > + */
> > > + if (legacy) {
> > > + msg->hdr.version = cpu_to_le16(3);
> > > + p = msg->front.iov_base + sizeof(*head);
> > > + } else {
> > > + struct ceph_mds_request_head *new_head = msg->front.iov_base;
> > > +
> > > + msg->hdr.version = cpu_to_le16(4);
> > > + new_head->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
> > > + p = msg->front.iov_base + sizeof(*new_head);
> > > + }
> > > +
> > > + head = find_old_request_head(msg->front.iov_base, legacy);
> > > +
> > > end = msg->front.iov_base + msg->front.iov_len;
> > >
> > > head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
> > > @@ -2583,12 +2638,7 @@ static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
> > >
> > > head->num_releases = cpu_to_le16(releases);
> > >
> > > - /* time stamp */
> > > - {
> > > - struct ceph_timespec ts;
> > > - ceph_encode_timespec64(&ts, &req->r_stamp);
> > > - ceph_encode_copy(&p, &ts, sizeof(ts));
> > > - }
> > > + encode_payload_tail(&p, req, legacy);
> > >
> > > if (WARN_ON_ONCE(p > end)) {
> > > ceph_msg_put(msg);
> > > @@ -2642,9 +2692,10 @@ static int __prepare_send_request(struct ceph_mds_session *session,
> > > {
> > > int mds = session->s_mds;
> > > struct ceph_mds_client *mdsc = session->s_mdsc;
> > > - struct ceph_mds_request_head *rhead;
> > > + struct ceph_mds_request_head_old *rhead;
> > > struct ceph_msg *msg;
> > > int flags = 0;
> > > + bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
> > >
> > > req->r_attempts++;
> > > if (req->r_inode) {
> > > @@ -2661,6 +2712,7 @@ static int __prepare_send_request(struct ceph_mds_session *session,
> > >
> > > if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
> > > void *p;
> > > +
> > > /*
> > > * Replay. Do not regenerate message (and rebuild
> > > * paths, etc.); just use the original message.
> > > @@ -2668,7 +2720,7 @@ static int __prepare_send_request(struct ceph_mds_session *session,
> > > * d_move mangles the src name.
> > > */
> > > msg = req->r_request;
> > > - rhead = msg->front.iov_base;
> > > + rhead = find_old_request_head(msg->front.iov_base, legacy);
> > >
> > > flags = le32_to_cpu(rhead->flags);
> > > flags |= CEPH_MDS_FLAG_REPLAY;
> > > @@ -2682,13 +2734,14 @@ static int __prepare_send_request(struct ceph_mds_session *session,
> > > /* remove cap/dentry releases from message */
> > > rhead->num_releases = 0;
> > >
> > > - /* time stamp */
> > > + /* verify that we haven't got mixed-feature MDSs */
> > > + if (legacy)
> > > + WARN_ON_ONCE(le16_to_cpu(msg->hdr.version) >= 4);
> > > + else
> > > + WARN_ON_ONCE(le16_to_cpu(msg->hdr.version) < 4);
> >
> > As mentioned in the ticket, I already did a minimal encode_gid_list()
> > helper -- just haven't pushed because I had to leave. Looking at this,
> > I not clear on why even bother with v3 vs v4 and the legacy branch.
> > The only that is conditional on CEPH_FEATURE_FS_BTIME is the head, we
> > can encode gids and set the version to 4 unconditionally.
>
> Sorry, what I meant is we can encode gids unconditionally, without
> regard to what head/which version was used as a result of checking
> whether CEPH_FEATURE_FS_BTIME is supported by the MDS.
>
Oh, I misunderstood. Yeah, that should be possible. I'll look at making
that change.
Thanks,
--
Jeff Layton <jlayton@xxxxxxxxxx>
