From: Dave Young <hidave.darkstar@gmail.com>
Date: Sat, 8 Jan 2011 10:09:13 +0000 (+0000)
Subject: btrfs: mount failure return value fix
X-Git-Tag: v2.6.38-rc1~14^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=20b450773d17e325190c158e10bfdb25dc21d2d6;p=pandora-kernel.git

btrfs: mount failure return value fix

I happened to pass swap partition as root partition in cmdline,
then kernel panic and tell me about "Cannot open root device".
It is not correct, in fact it is a fs type mismatch instead of 'no device'.

Eventually I found btrfs mounting failed with -EIO, it should be -EINVAL.
The logic in init/do_mounts.c:
        for (p = fs_names; *p; p += strlen(p)+1) {
                int err = do_mount_root(name, p, flags, root_mount_data);
                switch (err) {
                        case 0:
                                goto out;
                        case -EACCES:
                                flags |= MS_RDONLY;
                                goto retry;
                        case -EINVAL:
                                continue;
                }
		print "Cannot open root device"
		panic
	}
SO fs type after btrfs will have no chance to mount

Here fix the return value as -EINVAL

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
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