6729 incremental replication stream of a fs tree with lots of snapsho…

…ts trips assert in zfs recv

Portions contributed by: Jason King <jason.king@joyent.com>
Reviewed by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Andy Fiddaman <andy@omnios.org>
Reviewed by: Toomas Soome <tsoome@me.com>
Approved by: Gordon Ross <gordon.w.ross@gmail.com>

usr/src/lib/libzfs/common/libzfs_impl.h

@@ -93,6 +93,7 @@ struct libzfs_handle {
 	boolean_t libzfs_prop_debug;
 	di_devlink_handle_t libzfs_devlink;
 	regex_t libzfs_urire;
+	uint64_t libzfs_max_nvlist;
 };
 
 struct zfs_handle {

usr/src/lib/libzfs/common/libzfs_sendrecv.c

@@ -929,6 +929,18 @@ send_iterate_fs(zfs_handle_t *zhp, void *arg)
 	nvlist_free(sd->snapprops);
 	nvlist_free(sd->snapholds);
 
+	/* Do not allow the size of the properties list to exceed the limit */
+	if ((fnvlist_size(nvfs) + fnvlist_size(sd->fss)) >
+	    zhp->zfs_hdl->libzfs_max_nvlist) {
+		(void) fprintf(stderr, dgettext(TEXT_DOMAIN,
+		    "warning: cannot send %s@%s: the size of the list of "
+		    "snapshots and properties is too large to be received "
+		    "successfully.\n"
+		    "Select a smaller number of snapshots to send.\n"),
+		    zhp->zfs_name, sd->tosnap);
+		rv = EZFS_NOSPC;
+		goto out;
+	}
 	/* add this fs to nvlist */
 	(void) snprintf(guidstring, sizeof (guidstring),
 	    "0x%llx", (longlong_t)guid);
@@ -1926,8 +1938,31 @@ zfs_send(zfs_handle_t *zhp, const char *fromsnap, const char *tosnap,
 			    flags->verbose, flags->backup,
 			    flags->holds, flags->props, &fss,
 			    &fsavl);
-			if (err)
+			if (err) {
+				nvlist_free(hdrnv);
+				goto err_out;
+			}
+
+			/*
+			 * Do not allow the size of the properties list to
+			 * exceed the limit
+			 */
+			if ((fnvlist_size(fss) + fnvlist_size(hdrnv)) >
+			    zhp->zfs_hdl->libzfs_max_nvlist) {
+				(void) snprintf(errbuf, sizeof (errbuf),
+				    dgettext(TEXT_DOMAIN,
+				    "warning: cannot send '%s': "
+				    "the size of the list of snapshots and "
+				    "properties is too large to be received "
+				    "successfully.\n"
+				    "Select a smaller number of snapshots to "
+				    "send.\n"),
+				    zhp->zfs_name);
+				nvlist_free(hdrnv);
+				err = zfs_error(zhp->zfs_hdl, EZFS_NOSPC,
+				    errbuf);
 				goto err_out;
+			}
 			VERIFY(0 == nvlist_add_nvlist(hdrnv, "fss", fss));
 			err = nvlist_pack(hdrnv, &packbuf, &buflen,
 			    NV_ENCODE_XDR, 0);
@@ -2198,8 +2233,6 @@ recv_read(libzfs_handle_t *hdl, int fd, void *buf, int ilen,
 	int rv;
 	int len = ilen;
 
-	assert(ilen <= SPA_MAXBLOCKSIZE);
-
 	do {
 		rv = read(fd, cp, len);
 		cp += rv;
@@ -2233,6 +2266,12 @@ recv_read_nvlist(libzfs_handle_t *hdl, int fd, int len, nvlist_t **nvp,
 	if (buf == NULL)
 		return (ENOMEM);
 
+	if (len > hdl->libzfs_max_nvlist) {
+		zfs_error_aux(hdl, dgettext(TEXT_DOMAIN, "nvlist too large"));
+		free(buf);
+		return (ENOMEM);
+	}
+
 	err = recv_read(hdl, fd, buf, len, byteswap, zc);
 	if (err != 0) {
 		free(buf);
@@ -3325,6 +3364,7 @@ recv_skip(libzfs_handle_t *hdl, int fd, boolean_t byteswap)
 			}
 			uint64_t payload_size =
 			    DRR_WRITE_PAYLOAD_SIZE(&drr->drr_u.drr_write);
+			assert(payload_size <= SPA_MAXBLOCKSIZE);
 			(void) recv_read(hdl, fd, buf,
 			    payload_size, B_FALSE, NULL);
 			break;

usr/src/lib/libzfs/common/libzfs_util.c

@@ -675,6 +675,8 @@ libzfs_handle_t *
 libzfs_init(void)
 {
 	libzfs_handle_t *hdl;
+	int error;
+	char *env;
 
 	if ((hdl = calloc(1, sizeof (libzfs_handle_t))) == NULL) {
 		return (NULL);
@@ -717,6 +719,20 @@ libzfs_init(void)
 	if (getenv("ZFS_PROP_DEBUG") != NULL) {
 		hdl->libzfs_prop_debug = B_TRUE;
 	}
+	if ((env = getenv("ZFS_SENDRECV_MAX_NVLIST")) != NULL) {
+		if ((error = zfs_nicestrtonum(hdl, env,
+		    &hdl->libzfs_max_nvlist))) {
+			errno = error;
+			(void) close(hdl->libzfs_fd);
+			(void) fclose(hdl->libzfs_mnttab);
+			(void) fclose(hdl->libzfs_sharetab);
+			regfree(&hdl->libzfs_urire);
+			free(hdl);
+			return (NULL);
+		}
+	} else {
+		hdl->libzfs_max_nvlist = (SPA_MAXBLOCKSIZE * 4);
+	}
 
 	return (hdl);
 }