diff options
authorStefan Behrens <sbehrens@giantdisaster.de>2013-08-19 18:51:13 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-09-26 17:18:27 -0700
commit42cc8e56740efe9acc271f4780b81ac5ecef188c (patch)
parentd2310f7119ba394d3256c221886c048189dcfb91 (diff)
Btrfs: don't allow the replace procedure on read only filesystems
commit bbb651e469d99f0088e286fdeb54acca7bb4ad4e upstream. If you start the replace procedure on a read only filesystem, at the end the procedure fails to write the updated dev_items to the chunk tree. The problem is that this error is not indicated except for a WARN_ON(). If the user now thinks that everything was done as expected and destroys the source device (with mkfs or with a hammer). The next mount fails with "failed to read chunk root" and the filesystem is gone. This commit adds code to fail the attempt to start the replace procedure if the filesystem is mounted read-only. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0f81d67cdc8..8dedf401967 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3299,6 +3299,9 @@ static long btrfs_ioctl_dev_replace(struct btrfs_root *root, void __user *arg)
switch (p->cmd) {
+ if (root->fs_info->sb->s_flags & MS_RDONLY)
+ return -EROFS;
if (atomic_xchg(
1)) {