LU-4008 mdt: Shrink default LOVEA reply buffers

[fs/lustre-release.git] / lustre / mdt / mdt_handler.c

diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index fb3ba0a..abb526a 100644 (file)
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -481,6 +481,32 @@ void mdt_client_compatibility(struct mdt_thread_info *info)
         EXIT;
 }
 
+int mdt_attr_get_eabuf_size(struct mdt_thread_info *info, struct mdt_object *o)
+{
+       const struct lu_env *env = info->mti_env;
+       int rc, rc2;
+
+       rc = mo_xattr_get(env, mdt_object_child(o), &LU_BUF_NULL,
+                         XATTR_NAME_LOV);
+
+       if (rc == -ENODATA)
+               rc = 0;
+
+       if (rc < 0)
+               goto out;
+
+       /* Is it a directory? Let's check for the LMV as well */
+       if (S_ISDIR(lu_object_attr(&mdt_object_child(o)->mo_lu))) {
+               rc2 = mo_xattr_get(env, mdt_object_child(o), &LU_BUF_NULL,
+                                  XATTR_NAME_LMV);
+               if ((rc2 < 0 && rc2 != -ENODATA) || (rc2 > rc))
+                       rc = rc2;
+       }
+
+out:
+       return rc;
+}
+
 static int mdt_big_xattr_get(struct mdt_thread_info *info, struct mdt_object *o,
                             const char *name)
 {
@@ -767,13 +793,15 @@ static int mdt_getattr_internal(struct mdt_thread_info *info,
                GOTO(out, rc = 0);
        }
 
-       buffer->lb_len = reqbody->eadatasize;
-       if (buffer->lb_len > 0) {
+       if (reqbody->eadatasize > 0) {
                buffer->lb_buf = req_capsule_server_get(pill, &RMF_MDT_MD);
                if (buffer->lb_buf == NULL)
                        GOTO(out, rc = -EPROTO);
+               buffer->lb_len = req_capsule_get_size(pill, &RMF_MDT_MD,
+                                                     RCL_SERVER);
        } else {
                buffer->lb_buf = NULL;
+               buffer->lb_len = 0;
                ma_need &= ~(MA_LOV | MA_LMV);
                CDEBUG(D_INFO, "%s: RPC from %s: does not need LOVEA.\n",
                       mdt_obd_name(info->mti_mdt),
@@ -1053,11 +1081,34 @@ int mdt_getattr(struct tgt_session_info *tsi)
 
        mode = lu_object_attr(&obj->mot_obj);
 
+       /* Readlink */
+       if (reqbody->valid & OBD_MD_LINKNAME) {
+               /* No easy way to know how long is the symlink, but it cannot
+                * be more than PATH_MAX, so we allocate +1 */
+               rc = PATH_MAX + 1;
+
+       /* A special case for fs ROOT: getattr there might fetch
+        * default EA for entire fs, not just for this dir!
+        */
+       } else if (lu_fid_eq(mdt_object_fid(obj),
+                            &info->mti_mdt->mdt_md_root_fid) &&
+                  (reqbody->valid & OBD_MD_FLDIREA) &&
+                  (lustre_msg_get_opc(mdt_info_req(info)->rq_reqmsg) ==
+                                                                MDS_GETATTR)) {
+               /* Should the default strping be bigger, mdt_fix_reply
+                * will reallocate */
+               rc = DEF_REP_MD_SIZE;
+       } else {
+               /* Hopefully no race in EA change for either file or directory?
+                */
+               rc = mdt_attr_get_eabuf_size(info, obj);
+       }
+
+       if (rc < 0)
+               GOTO(out_shrink, rc);
+
        /* old clients may not report needed easize, use max value then */
-       req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER,
-                            reqbody->eadatasize == 0 ?
-                            info->mti_mdt->mdt_max_mdsize :
-                            reqbody->eadatasize);
+       req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER, rc);
 
        rc = req_capsule_server_pack(pill);
        if (unlikely(rc != 0))
@@ -1768,7 +1819,7 @@ static int mdt_reint_internal(struct mdt_thread_info *info,
         /* for replay (no_create) lmm is not needed, client has it already */
         if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER))
                 req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER,
-                                     info->mti_rr.rr_eadatalen);
+                                    DEF_REP_MD_SIZE);
 
        /* llog cookies are always 0, the field is kept for compatibility */
         if (req_capsule_has_field(pill, &RMF_LOGCOOKIES, RCL_SERVER))
@@ -2702,7 +2753,7 @@ static int mdt_unpack_req_pack_rep(struct mdt_thread_info *info, __u32 flags)
                 /* Pack reply. */
                 if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER))
                         req_capsule_set_size(pill, &RMF_MDT_MD, RCL_SERVER,
-                                             info->mti_body->eadatasize);
+                                            DEF_REP_MD_SIZE);
                 if (req_capsule_has_field(pill, &RMF_LOGCOOKIES, RCL_SERVER))
                        req_capsule_set_size(pill, &RMF_LOGCOOKIES,
                                             RCL_SERVER, 0);