From: Ilya Dryomov <idryomov@gmail.com>
Date: Tue, 15 Feb 2011 18:14:25 +0000 (+0000)
Subject: Btrfs: make btrfs_rm_device() fail gracefully
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9b3517e9136824346227b7b04f8f7ea1f3a726cc;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

Btrfs: make btrfs_rm_device() fail gracefully

If shrinking done as part of the online device removal fails add that
device back to the allocation list and increment the rw_devices counter.
This fixes two bugs:

1) we could have a perfectly good device out of alloc list for no good
reason;

2) in the btrfs consisting of two devices, failure in btrfs_rm_device()
could lead to a situation where it was impossible to remove any of the
devices because of the "unable to remove the only writeable device"
error.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index dadaaa8005c8..f31c33119bb6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1337,11 +1337,11 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 
 	ret = btrfs_shrink_device(device, 0);
 	if (ret)
-		goto error_brelse;
+		goto error_undo;
 
 	ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
 	if (ret)
-		goto error_brelse;
+		goto error_undo;
 
 	device->in_fs_metadata = 0;
 
@@ -1415,6 +1415,13 @@ out:
 	mutex_unlock(&root->fs_info->volume_mutex);
 	mutex_unlock(&uuid_mutex);
 	return ret;
+error_undo:
+	if (device->writeable) {
+		list_add(&device->dev_alloc_list,
+			 &root->fs_info->fs_devices->alloc_list);
+		root->fs_info->fs_devices->rw_devices++;
+	}
+	goto error_brelse;
 }
 
 /*