libceph: redo callbacks and factor out MOSDOpReply decoding

If you specify ACK | ONDISK and set ->r_unsafe_callback, both
->r_callback and ->r_unsafe_callback(true) are called on ack.  This is
very confusing.  Redo this so that only one of them is called:

    ->r_unsafe_callback(true), on ack
    ->r_unsafe_callback(false), on commit

or

    ->r_callback, on ack|commit

Decode everything in decode_MOSDOpReply() to reduce clutter.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 209 insertions, 153 deletions

diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 2a30c0bb3045..baf2844b00d6 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -1693,6 +1693,14 @@ static int __ceph_osdc_start_request(struct ceph_osd_client *osdc,
         return 0;
 }
 
+static void __complete_request(struct ceph_osd_request *req)
+{
+        if (req->r_callback)
+                req->r_callback(req);
+        else
+                complete_all(&req->r_completion);
+}
+
 /*
  * Timeout callback, called every N seconds when 1 or more osd
  * requests has been active for more than N seconds.  When this
@@ -1875,107 +1883,76 @@ e_inval:
         goto out;
 }
 
-static void complete_request(struct ceph_osd_request *req)
-{
-        complete_all(&req->r_safe_completion);  /* fsync waiter */
-}
+struct MOSDOpReply {
+        struct ceph_pg pgid;
+        u64 flags;
+        int result;
+        u32 epoch;
+        int num_ops;
+        u32 outdata_len[CEPH_OSD_MAX_OPS];
+        s32 rval[CEPH_OSD_MAX_OPS];
+        int retry_attempt;
+        struct ceph_eversion replay_version;
+        u64 user_version;
+        struct ceph_request_redirect redirect;
+};
 
-/*
- * handle osd op reply.  either call the callback if it is specified,
- * or do the completion to wake up the waiting thread.
- */
-static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
+static int decode_MOSDOpReply(const struct ceph_msg *msg, struct MOSDOpReply *m)
 {
-        void *p, *end;
-        struct ceph_osd_request *req;
-        struct ceph_request_redirect redir;
-        u64 tid;
-        int object_len;
-        unsigned int numops;
-        int payload_len, flags;
-        s32 result;
-        s32 retry_attempt;
-        struct ceph_pg pg;
-        int err;
-        u32 reassert_epoch;
-        u64 reassert_version;
-        u32 osdmap_epoch;
-        int already_completed;
-        u32 bytes;
+        void *p = msg->front.iov_base;
+        void *const end = p + msg->front.iov_len;
+        u16 version = le16_to_cpu(msg->hdr.version);
+        struct ceph_eversion bad_replay_version;
         u8 decode_redir;
-        unsigned int i;
-
-        tid = le64_to_cpu(msg->hdr.tid);
-        dout("handle_reply %p tid %llu\n", msg, tid);
-
-        p = msg->front.iov_base;
-        end = p + msg->front.iov_len;
+        u32 len;
+        int ret;
+        int i;
 
-        ceph_decode_need(&p, end, 4, bad);
-        object_len = ceph_decode_32(&p);
-        ceph_decode_need(&p, end, object_len, bad);
-        p += object_len;
+        ceph_decode_32_safe(&p, end, len, e_inval);
+        ceph_decode_need(&p, end, len, e_inval);
+        p += len; /* skip oid */
 
-        err = ceph_decode_pgid(&p, end, &pg);
-        if (err)
-                goto bad;
+        ret = ceph_decode_pgid(&p, end, &m->pgid);
+        if (ret)
+                return ret;
 
-        ceph_decode_need(&p, end, 8 + 4 + 4 + 8 + 4, bad);
-        flags = ceph_decode_64(&p);
-        result = ceph_decode_32(&p);
-        reassert_epoch = ceph_decode_32(&p);
-        reassert_version = ceph_decode_64(&p);
-        osdmap_epoch = ceph_decode_32(&p);
+        ceph_decode_64_safe(&p, end, m->flags, e_inval);
+        ceph_decode_32_safe(&p, end, m->result, e_inval);
+        ceph_decode_need(&p, end, sizeof(bad_replay_version), e_inval);
+        memcpy(&bad_replay_version, p, sizeof(bad_replay_version));
+        p += sizeof(bad_replay_version);
+        ceph_decode_32_safe(&p, end, m->epoch, e_inval);
 
-        /* lookup */
-        down_read(&osdc->map_sem);
-        mutex_lock(&osdc->request_mutex);
-        req = lookup_request(&osdc->requests, tid);
-        if (req == NULL) {
-                dout("handle_reply tid %llu dne\n", tid);
-                goto bad_mutex;
-        }
-        ceph_osdc_get_request(req);
+        ceph_decode_32_safe(&p, end, m->num_ops, e_inval);
+        if (m->num_ops > ARRAY_SIZE(m->outdata_len))
+                goto e_inval;
 
-        dout("handle_reply %p tid %llu req %p result %d\n", msg, tid,
-             req, result);
-
-        ceph_decode_need(&p, end, 4, bad_put);
-        numops = ceph_decode_32(&p);
-        if (numops > CEPH_OSD_MAX_OPS)
-                goto bad_put;
-        if (numops != req->r_num_ops)
-                goto bad_put;
-        payload_len = 0;
-        ceph_decode_need(&p, end, numops * sizeof(struct ceph_osd_op), bad_put);
-        for (i = 0; i < numops; i++) {
+        ceph_decode_need(&p, end, m->num_ops * sizeof(struct ceph_osd_op),
+                         e_inval);
+        for (i = 0; i < m->num_ops; i++) {
                 struct ceph_osd_op *op = p;
-                int len;
 
-                len = le32_to_cpu(op->payload_len);
-                req->r_ops[i].outdata_len = len;
-                dout(" op %d has %d bytes\n", i, len);
-                payload_len += len;
+                m->outdata_len[i] = le32_to_cpu(op->payload_len);
                 p += sizeof(*op);
         }
-        bytes = le32_to_cpu(msg->hdr.data_len);
-        if (payload_len != bytes) {
-                pr_warn("sum of op payload lens %d != data_len %d\n",
-                        payload_len, bytes);
-                goto bad_put;
-        }
 
-        ceph_decode_need(&p, end, 4 + numops * 4, bad_put);
-        retry_attempt = ceph_decode_32(&p);
-        for (i = 0; i < numops; i++)
-                req->r_ops[i].rval = ceph_decode_32(&p);
+        ceph_decode_32_safe(&p, end, m->retry_attempt, e_inval);
+        for (i = 0; i < m->num_ops; i++)
+                ceph_decode_32_safe(&p, end, m->rval[i], e_inval);
 
-        if (le16_to_cpu(msg->hdr.version) >= 6) {
-                p += 8 + 4; /* skip replay_version */
-                p += 8; /* skip user_version */
+        if (version >= 5) {
+                ceph_decode_need(&p, end, sizeof(m->replay_version), e_inval);
+                memcpy(&m->replay_version, p, sizeof(m->replay_version));
+                p += sizeof(m->replay_version);
+                ceph_decode_64_safe(&p, end, m->user_version, e_inval);
+        } else {
+                m->replay_version = bad_replay_version; /* struct */
+                m->user_version = le64_to_cpu(m->replay_version.version);
+        }
 
-                if (le16_to_cpu(msg->hdr.version) >= 7)
-                        ceph_decode_8_safe(&p, end, decode_redir, bad_put);
+        if (version >= 6) {
+                if (version >= 7)
+                        ceph_decode_8_safe(&p, end, decode_redir, e_inval);
                 else
                         decode_redir = 1;
         } else {
@@ -1983,19 +1960,96 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
         }
 
         if (decode_redir) {
-                err = ceph_redirect_decode(&p, end, &redir);
-                if (err)
-                        goto bad_put;
+                ret = ceph_redirect_decode(&p, end, &m->redirect);
+                if (ret)
+                        return ret;
         } else {
-                redir.oloc.pool = -1;
+                ceph_oloc_init(&m->redirect.oloc);
         }
 
-        if (!ceph_oloc_empty(&redir.oloc)) {
-                dout("redirect pool %lld\n", redir.oloc.pool);
+        return 0;
+
+e_inval:
+        return -EINVAL;
+}
+
+/*
+ * We are done with @req if
+ *   - @m is a safe reply, or
+ *   - @m is an unsafe reply and we didn't want a safe one
+ */
+static bool done_request(const struct ceph_osd_request *req,
+                         const struct MOSDOpReply *m)
+{
+        return (m->result < 0 ||
+                (m->flags & CEPH_OSD_FLAG_ONDISK) ||
+                !(req->r_flags & CEPH_OSD_FLAG_ONDISK));
+}
 
+/*
+ * handle osd op reply.  either call the callback if it is specified,
+ * or do the completion to wake up the waiting thread.
+ *
+ * ->r_unsafe_callback is set?  yes                     no
+ *
+ * first reply is OK (needed    r_cb/r_completion,      r_cb/r_completion,
+ * any or needed/got safe)      r_safe_completion       r_safe_completion
+ *
+ * first reply is unsafe        r_unsafe_cb(true)       (nothing)
+ *
+ * when we get the safe reply   r_unsafe_cb(false),     r_cb/r_completion,
+ *                              r_safe_completion       r_safe_completion
+ */
+static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
+{
+        struct ceph_osd_request *req;
+        struct MOSDOpReply m;
+        u64 tid = le64_to_cpu(msg->hdr.tid);
+        u32 data_len = 0;
+        bool already_acked;
+        int ret;
+        int i;
+
+        dout("%s msg %p tid %llu\n", __func__, msg, tid);
+
+        down_read(&osdc->map_sem);
+        mutex_lock(&osdc->request_mutex);
+        req = lookup_request(&osdc->requests, tid);
+        if (!req) {
+                dout("%s no tid %llu\n", __func__, tid);
+                goto out_unlock;
+        }
+        ceph_osdc_get_request(req);
+
+        ret = decode_MOSDOpReply(msg, &m);
+        if (ret) {
+                pr_err("failed to decode MOSDOpReply for tid %llu: %d\n",
+                       req->r_tid, ret);
+                ceph_msg_dump(msg);
+                goto fail_request;
+        }
+        dout("%s req %p tid %llu flags 0x%llx pgid %llu.%x epoch %u attempt %d v %u'%llu uv %llu\n",
+             __func__, req, req->r_tid, m.flags, m.pgid.pool, m.pgid.seed,
+             m.epoch, m.retry_attempt, le32_to_cpu(m.replay_version.epoch),
+             le64_to_cpu(m.replay_version.version), m.user_version);
+
+        if (m.retry_attempt >= 0) {
+                if (m.retry_attempt != req->r_attempts - 1) {
+                        dout("req %p tid %llu retry_attempt %d != %d, ignoring\n",
+                             req, req->r_tid, m.retry_attempt,
+                             req->r_attempts - 1);
+                        goto out_put;
+                }
+        } else {
+                WARN_ON(1); /* MOSDOpReply v4 is assumed */
+        }
+
+        if (!ceph_oloc_empty(&m.redirect.oloc)) {
+                dout("req %p tid %llu redirect pool %lld\n", req, req->r_tid,
+                     m.redirect.oloc.pool);
                 __unregister_request(osdc, req);
 
-                ceph_oloc_copy(&req->r_t.target_oloc, &redir.oloc);
+                ceph_oloc_copy(&req->r_t.target_oloc, &m.redirect.oloc);
 
                 /*
                  * Start redirect requests with nofail=true.  If
@@ -2005,85 +2059,85 @@ static void handle_reply(struct ceph_osd_client *osdc, struct ceph_msg *msg)
                  * successfully.  In the future we might want to follow
                  * original request's nofail setting here.
                  */
-                err = __ceph_osdc_start_request(osdc, req, true);
-                BUG_ON(err);
+                ret = __ceph_osdc_start_request(osdc, req, true);
+                BUG_ON(ret);
 
-                goto out_unlock;
+                goto out_put;
         }
 
-        already_completed = req->r_got_reply;
-        if (!req->r_got_reply) {
-                req->r_result = result;
-                dout("handle_reply result %d bytes %d\n", req->r_result,
-                     bytes);
-                if (req->r_result == 0)
-                        req->r_result = bytes;
-
-                /* in case this is a write and we need to replay, */
-                req->r_replay_version.epoch = cpu_to_le32(reassert_epoch);
-                req->r_replay_version.version = cpu_to_le64(reassert_version);
-
-                req->r_got_reply = 1;
-        } else if ((flags & CEPH_OSD_FLAG_ONDISK) == 0) {
-                dout("handle_reply tid %llu dup ack\n", tid);
-                goto out_unlock;
+        if (m.num_ops != req->r_num_ops) {
+                pr_err("num_ops %d != %d for tid %llu\n", m.num_ops,
+                       req->r_num_ops, req->r_tid);
+                goto fail_request;
         }
-
-        dout("handle_reply tid %llu flags %d\n", tid, flags);
-
-        if (req->r_linger && (flags & CEPH_OSD_FLAG_ONDISK))
-                __register_linger_request(osdc, req);
-
-        /* either this is a read, or we got the safe response */
-        if (result < 0 ||
-            (flags & CEPH_OSD_FLAG_ONDISK) ||
-            ((flags & CEPH_OSD_FLAG_WRITE) == 0))
+        for (i = 0; i < req->r_num_ops; i++) {
+                dout(" req %p tid %llu op %d rval %d len %u\n", req,
+                     req->r_tid, i, m.rval[i], m.outdata_len[i]);
+                req->r_ops[i].rval = m.rval[i];
+                req->r_ops[i].outdata_len = m.outdata_len[i];
+                data_len += m.outdata_len[i];
+        }
+        if (data_len != le32_to_cpu(msg->hdr.data_len)) {
+                pr_err("sum of lens %u != %u for tid %llu\n", data_len,
+                       le32_to_cpu(msg->hdr.data_len), req->r_tid);
+                goto fail_request;
+        }
+        dout("%s req %p tid %llu acked %d result %d data_len %u\n", __func__,
+             req, req->r_tid, req->r_got_reply, m.result, data_len);
+
+        already_acked = req->r_got_reply;
+        if (!already_acked) {
+                req->r_result = m.result ?: data_len;
+                req->r_replay_version = m.replay_version; /* struct */
+                req->r_got_reply = true;
+        } else if (!(m.flags & CEPH_OSD_FLAG_ONDISK)) {
+                dout("req %p tid %llu dup ack\n", req, req->r_tid);
+                goto out_put;
+        }
+
+        if (done_request(req, &m)) {
                 __unregister_request(osdc, req);
+                if (req->r_linger) {
+                        WARN_ON(req->r_unsafe_callback);
+                        __register_linger_request(osdc, req);
+                }
+        }
 
         mutex_unlock(&osdc->request_mutex);
         up_read(&osdc->map_sem);
 
-        if (!already_completed) {
-                if (req->r_unsafe_callback &&
-                    result >= 0 && !(flags & CEPH_OSD_FLAG_ONDISK))
-                        req->r_unsafe_callback(req, true);
-                if (req->r_callback)
-                        req->r_callback(req);
-                else
-                        complete_all(&req->r_completion);
-        }
-
-        if (flags & CEPH_OSD_FLAG_ONDISK) {
-                if (req->r_unsafe_callback && already_completed)
+        if (done_request(req, &m)) {
+                if (already_acked && req->r_unsafe_callback) {
+                        dout("req %p tid %llu safe-cb\n", req, req->r_tid);
                         req->r_unsafe_callback(req, false);
-                complete_request(req);
+                } else {
+                        dout("req %p tid %llu cb\n", req, req->r_tid);
+                        __complete_request(req);
+                }
+        } else {
+                if (req->r_unsafe_callback) {
+                        dout("req %p tid %llu unsafe-cb\n", req, req->r_tid);
+                        req->r_unsafe_callback(req, true);
+                } else {
+                        WARN_ON(1);
+                }
         }
+        if (m.flags & CEPH_OSD_FLAG_ONDISK)
+                complete_all(&req->r_safe_completion);
 
-out:
-        dout("req=%p req->r_linger=%d\n", req, req->r_linger);
         ceph_osdc_put_request(req);
         return;
-out_unlock:
-        mutex_unlock(&osdc->request_mutex);
-        up_read(&osdc->map_sem);
-        goto out;
 
-bad_put:
+fail_request:
         req->r_result = -EIO;
         __unregister_request(osdc, req);
-        if (req->r_callback)
-                req->r_callback(req);
-        else
-                complete_all(&req->r_completion);
-        complete_request(req);
+        __complete_request(req);
+        complete_all(&req->r_safe_completion);
+out_put:
         ceph_osdc_put_request(req);
-bad_mutex:
+out_unlock:
         mutex_unlock(&osdc->request_mutex);
         up_read(&osdc->map_sem);
-bad:
-        pr_err("corrupt osd_op_reply got %d %d\n",
-               (int)msg->front.iov_len, le32_to_cpu(msg->hdr.front_len));
-        ceph_msg_dump(msg);
 }
 
 static void reset_changed_osds(struct ceph_osd_client *osdc)
@@ -2591,7 +2645,9 @@ int ceph_osdc_wait_request(struct ceph_osd_client *osdc,
         if (rc < 0) {
                 dout("%s %p tid %llu interrupted\n", __func__, req, req->r_tid);
                 ceph_osdc_cancel_request(req);
-                complete_request(req);
+
+                /* kludge - need to to wake ceph_osdc_sync() */
+                complete_all(&req->r_safe_completion);
                 return rc;
         }