[Btrfs-devel] btrfs-0.13 breaks boot on reiserfs-3.6

[Yan Zheng]

2008/3/15, fdbugs <fdbugs at dupoux.com>:
> Hi,
>
>  I recompiled my kernel today, and when the btrfs-0.13 option is
>  enabled (CONFIG_BTR_FS=y) I cannot boot on my reiserfs-3.6 partition
>  any more. The kernel says that is cannot mount /dev/sdc6. I can boot
>  the kernel when I recompile it with the same options and
>  CONFIG_BTR_FS=n, and with the same boot options as well. Everything is
>  amd64 on my system (kernel + programs).
>
>  Here is a screenshot of the error:
>  http://temp.dupoux.com/btrfs/btrfs-0.13-bug-reiserfs.png
>
>  Here are my kernel options (it's 2.6.24.3 with several patches)
>  http://temp.dupoux.com/btrfs/btrfs-0.13-bug-reiserfs-working.cfg (the
>  one with CONFIG_BTR_FS=n that works)
>
>  Here are the kernel patches I am using:
>  http://temp.dupoux.com/btrfs/patches/
>
>  Thanks
>

This bug is caused by wrong error code. btrfs_fill_super should return
-EINVAL instead of -EIO when no btrfs found on the device. Please try
the patch attached below.

Regards
YZ
---
diff -r e4cd88595ed7 disk-io.c
--- a/disk-io.c	Thu Feb 21 14:54:12 2008 -0500
+++ b/disk-io.c	Sat Mar 15 23:44:53 2008 +0800
@@ -635,7 +635,7 @@ struct btrfs_root *open_ctree(struct sup
 	struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
 						GFP_NOFS);
 	int ret;
-	int err = -EIO;
+	int err = -EINVAL;
 	struct btrfs_super_block *disk_super;

 	if (!extent_root || !tree_root || !fs_info) {
diff -r e4cd88595ed7 super.c
--- a/super.c	Thu Feb 21 14:54:12 2008 -0500
+++ b/super.c	Sat Mar 15 23:44:53 2008 +0800
@@ -232,9 +232,9 @@ static int btrfs_fill_super(struct super

 	tree_root = open_ctree(sb);

-	if (!tree_root || IS_ERR(tree_root)) {
+	if (IS_ERR(tree_root)) {
 		printk("btrfs: open_ctree failed\n");
-		return -EIO;
+		return PTR_ERR(tree_root);
 	}
 	sb->s_fs_info = tree_root;
 	disk_super = &tree_root->fs_info->super_copy;