From: Brian Behlendorf <behlendorf1@llnl.gov>
Date: Wed, 17 Jul 2013 16:15:46 +0000 (-0700)
Subject: Fix read-only pool hang on unmount
X-Git-Url: https://git.camperquake.de/gitweb.cgi?p=zfs.git;a=commitdiff_plain;h=c9ada6d5a00ba66fd54d62b4a1684e561fe2c9a4

Fix read-only pool hang on unmount

During mount a filesystem dataset would have the MS_RDONLY bit
incorrectly cleared even if the entire pool was read-only.
There is existing to code to handle this case but it was being run
before the property callbacks were registered.  To resolve the
issue we move this read-only code after the callback registration.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1338
---

diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c
index 602c332..9ae7ab5 100644
--- a/module/zfs/zfs_vfsops.c
+++ b/module/zfs/zfs_vfsops.c
@@ -233,10 +233,11 @@ zfs_register_callbacks(zfs_sb_t *zsb)
 {
 	struct dsl_dataset *ds = NULL;
 	objset_t *os = zsb->z_os;
+	boolean_t do_readonly = B_FALSE;
 	int error = 0;
 
 	if (zfs_is_readonly(zsb) || !spa_writeable(dmu_objset_spa(os)))
-		readonly_changed_cb(zsb, B_TRUE);
+		do_readonly = B_TRUE;
 
 	/*
 	 * Register property callbacks.
@@ -271,6 +272,9 @@ zfs_register_callbacks(zfs_sb_t *zsb)
 	if (error)
 		goto unregister;
 
+	if (do_readonly)
+		readonly_changed_cb(zsb, B_TRUE);
+
 	return (0);
 
 unregister: