LU-10513 acl: prepare small buffer for ACL RPC reply

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

diff --git a/lustre/mdt/mdt_handler.c b/lustre/mdt/mdt_handler.c
index 2bac82f..826dd04 100644 (file)
--- a/lustre/mdt/mdt_handler.c
+++ b/lustre/mdt/mdt_handler.c
@@ -539,13 +539,13 @@ int mdt_pack_acl2body(struct mdt_thread_info *info, struct mdt_body *repbody,
        struct md_object        *next = mdt_object_child(o);
        struct lu_buf           *buf = &info->mti_buf;
        struct mdt_device       *mdt = info->mti_mdt;
+       struct req_capsule *pill = info->mti_pill;
        int rc;
 
        ENTRY;
 
-       buf->lb_buf = req_capsule_server_get(info->mti_pill, &RMF_ACL);
-       buf->lb_len = req_capsule_get_size(info->mti_pill, &RMF_ACL,
-                                          RCL_SERVER);
+       buf->lb_buf = req_capsule_server_get(pill, &RMF_ACL);
+       buf->lb_len = req_capsule_get_size(pill, &RMF_ACL, RCL_SERVER);
        if (buf->lb_len == 0)
                RETURN(0);
 
@@ -593,6 +593,36 @@ again:
                               mdt_obd_name(mdt), PFID(mdt_object_fid(o)), rc);
                }
        } else {
+               int client;
+               int server;
+               int acl_buflen;
+               int lmm_buflen = 0;
+               int lmmsize = 0;
+
+               acl_buflen = req_capsule_get_size(pill, &RMF_ACL, RCL_SERVER);
+               if (acl_buflen >= rc)
+                       goto map;
+
+               /* If LOV/LMA EA is small, we can reuse part of their buffer */
+               client = ptlrpc_req_get_repsize(pill->rc_req);
+               server = lustre_packed_msg_size(pill->rc_req->rq_repmsg);
+               if (req_capsule_has_field(pill, &RMF_MDT_MD, RCL_SERVER)) {
+                       lmm_buflen = req_capsule_get_size(pill, &RMF_MDT_MD,
+                                                         RCL_SERVER);
+                       lmmsize = repbody->mbo_eadatasize;
+               }
+
+               if (client < server - acl_buflen - lmm_buflen + rc + lmmsize) {
+                       CDEBUG(D_INODE, "%s: client prepared buffer size %d "
+                              "is not big enough with the ACL size %d (%d)\n",
+                              mdt_obd_name(mdt), client, rc,
+                              server - acl_buflen - lmm_buflen + rc + lmmsize);
+                       repbody->mbo_aclsize = 0;
+                       repbody->mbo_valid &= ~OBD_MD_FLACL;
+                       RETURN(-ERANGE);
+               }
+
+map:
                if (buf->lb_buf == info->mti_big_acl)
                        info->mti_big_acl_used = 1;
 
@@ -603,6 +633,8 @@ again:
                        CERROR("%s: nodemap_map_acl unable to parse "DFID
                               " ACL: rc = %d\n", mdt_obd_name(mdt),
                               PFID(mdt_object_fid(o)), rc);
+                       repbody->mbo_aclsize = 0;
+                       repbody->mbo_valid &= ~OBD_MD_FLACL;
                } else {
                        repbody->mbo_aclsize = rc;
                        repbody->mbo_valid |= OBD_MD_FLACL;