From: Miklos Szeredi <mszeredi@suse.cz>
Date: Thu, 20 Nov 2014 15:08:59 +0000 (+0100)
Subject: init: fix read-write root mount
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=10975933da3d65f8833d4ce98dcc2ecc63a695d6;p=openwrt%2Fstaging%2Fblogic.git

init: fix read-write root mount

If mount flags don't have MS_RDONLY, iso9660 returns EACCES without actually
checking if it's an iso image.

This tricks mount_block_root() into retrying with MS_RDONLY.  This results
in a read-only root despite the "rw" boot parameter if the actual
filesystem was checked after iso9660.

I believe the behavior of iso9660 is okay, while that of mount_block_root()
is not.  It should rather try all types without MS_RDONLY and only then
retry with MS_RDONLY.

This change also makes the code more robust against the case when EACCES is
returned despite MS_RDONLY, which would've resulted in a lockup.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/init/do_mounts.c b/init/do_mounts.c
index 9b3565c41502..eb410083e8e0 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -395,8 +395,6 @@ retry:
 			case 0:
 				goto out;
 			case -EACCES:
-				flags |= MS_RDONLY;
-				goto retry;
 			case -EINVAL:
 				continue;
 		}
@@ -419,6 +417,10 @@ retry:
 #endif
 		panic("VFS: Unable to mount root fs on %s", b);
 	}
+	if (!(flags & MS_RDONLY)) {
+		flags |= MS_RDONLY;
+		goto retry;
+	}
 
 	printk("List of all partitions:\n");
 	printk_all_partitions();