[PATCH resend] init: fix read-write root mount

From: Miklos Szeredi
Date: Mon Nov 24 2014 - 08:25:41 EST


From: Miklos Szeredi <mszeredi@xxxxxxx>

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@xxxxxxx>
---
init/do_mounts.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -395,8 +395,6 @@ void __init mount_block_root(char *name,
case 0:
goto out;
case -EACCES:
- flags |= MS_RDONLY;
- goto retry;
case -EINVAL:
continue;
}
@@ -419,6 +417,10 @@ void __init mount_block_root(char *name,
#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();
--
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