From: Sebastien Buisson <sbuisson@ddn.com>
Date: Tue, 8 Mar 2022 11:07:47 +0000 (+0100)
Subject: LU-15625 sec: fix set_param -P for root squash
X-Git-Tag: 2.15.51~99
X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=commitdiff_plain;h=7b8449e8f9ed310376a191ec8dfa2f1cb6233377

LU-15625 sec: fix set_param -P for root squash

lctl set_param -P needs to be fixed for root squash in order
to properly propagate to clients.
On server (MDT) side, the paramaters are mdt.*.*squash*.
On client side, the parameters are llite.*.*squash*.
So if the setting on MGS side is done as
set_param -P *.*.root_squash and
*.*.nosquash_nids, it works fine. But if it is done as
set_param -P mdt.*.root_squash, this setting is not applied to
client side.
The solution is to have the settings translated into
*.*.root_squash and *.*.nosquash_nids to make both sides happy.

Also, to ensure client vs. server consistency, prevent
set_param -P llite.*.root_squash.

Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I8984c9d9024d7a053e548ed15d1321b281d9940f
Reviewed-on: https://review.whamcloud.com/46739
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: John L. Hammond <jhammond@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/lustre/include/uapi/linux/lustre/lustre_param.h b/lustre/include/uapi/linux/lustre/lustre_param.h
index 284c63b..8b91770 100644
--- a/lustre/include/uapi/linux/lustre/lustre_param.h
+++ b/lustre/include/uapi/linux/lustre/lustre_param.h
@@ -68,6 +68,8 @@
 #define PARAM_ACTIVE               "active="           /* activate/deactivate */
 #define PARAM_NETWORK              "network="          /* bind on nid */
 #define PARAM_ID_UPCALL		"identity_upcall="  /* identity upcall */
+#define PARAM_ROOTSQUASH	   "root_squash="      /* root squash */
+#define PARAM_NOSQUASHNIDS	   "nosquash_nids="    /* no squash nids */
 
 /* Prefixes for parameters handled by obd's proc methods (XXX_process_config) */
 #define PARAM_OST		"ost."
diff --git a/lustre/mgs/mgs_llog.c b/lustre/mgs/mgs_llog.c
index c276563..0762776 100644
--- a/lustre/mgs/mgs_llog.c
+++ b/lustre/mgs/mgs_llog.c
@@ -3919,6 +3919,21 @@ static int mgs_write_log_param2(const struct lu_env *env,
 		goto end;
 	}
 
+	/* root squash parameters must not be set on llite subsystem, this can
+	 * lead to inconsistencies between client and server values
+	 */
+	if ((strstr(ptr, PARAM_NOSQUASHNIDS) ||
+	     strstr(ptr, PARAM_ROOTSQUASH)) &&
+	    strncmp(ptr, "llite.", strlen("llite.")) == 0) {
+		rc = -EINVAL;
+		CWARN("%s: cannot add %s param to llite subsystem, use mdt instead: rc=%d\n",
+		      mgs->mgs_obd->obd_name,
+		      strstr(ptr, PARAM_ROOTSQUASH) ?
+			PARAM_ROOTSQUASH : PARAM_NOSQUASHNIDS,
+		      rc);
+		goto end;
+	}
+
 	rc = mgs_wlp_lcfg(env, mgs, fsdb, mti, PARAMS_FILENAME, &bufs,
 			  mti->mti_svname, ptr);
 end:
diff --git a/lustre/obdclass/obd_config.c b/lustre/obdclass/obd_config.c
index 8b2fcdc..6f49fc9 100644
--- a/lustre/obdclass/obd_config.c
+++ b/lustre/obdclass/obd_config.c
@@ -1261,6 +1261,7 @@ static ssize_t process_param2_config(struct lustre_cfg *lcfg)
 	char *upcall = lustre_cfg_string(lcfg, 2);
 	struct kobject *kobj = NULL;
 	const char *subsys = param;
+	char *newparam = NULL;
 	char *argv[] = {
 		[0] = "/usr/sbin/lctl",
 		[1] = "set_param",
@@ -1277,15 +1278,15 @@ static ssize_t process_param2_config(struct lustre_cfg *lcfg)
 
 	len = strcspn(param, ".=");
 	if (!len)
-		return -EINVAL;
+		RETURN(-EINVAL);
 
 	/* If we find '=' then its the top level sysfs directory */
 	if (param[len] == '=')
-		return class_set_global(param);
+		RETURN(class_set_global(param));
 
 	subsys = kstrndup(param, len, GFP_KERNEL);
 	if (!subsys)
-		return -ENOMEM;
+		RETURN(-ENOMEM);
 
 	kobj = kset_find_obj(lustre_kset, subsys);
 	kfree(subsys);
@@ -1316,6 +1317,22 @@ static ssize_t process_param2_config(struct lustre_cfg *lcfg)
 		RETURN(-EINVAL);
 	}
 
+	/* root_squash and nosquash_nids settings must be applied to
+	 * global subsystem (*.) so that it is taken into account by
+	 * both client and server sides. So do the equivalent of a
+	 * 's / mdt. / *. /'.
+	 */
+	if ((strstr(param, PARAM_NOSQUASHNIDS) ||
+	     strstr(param, PARAM_ROOTSQUASH)) &&
+	    (param[0] != '*' || param[1] != '.')) {
+		newparam = kmalloc(strlen(param) + 1, GFP_NOFS);
+		if (!newparam)
+			RETURN(-ENOMEM);
+
+		snprintf(newparam, strlen(param) + 1, "*%s", param + len);
+		argv[2] = (char *)newparam;
+	}
+
 	start = ktime_get();
 	rc = call_usermodehelper(argv[0], argv, NULL, UMH_WAIT_PROC);
 	end = ktime_get();
@@ -1331,6 +1348,7 @@ static ssize_t process_param2_config(struct lustre_cfg *lcfg)
 		       rc = 0;
 	}
 
+	kfree(newparam);
 	RETURN(rc);
 }