btrfs: add write protection to SET_FEATURES ioctl

Perform the want_write check if we get far enough to do any writes.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2016-05-04 11:32:00 +02:00 committed by David Sterba
parent 48b3b9d401
commit 7ab19625a9

View file

@ -5406,9 +5406,15 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
if (ret)
return ret;
ret = mnt_want_write_file(file);
if (ret)
return ret;
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
goto out_drop_write;
}
spin_lock(&root->fs_info->super_lock);
newflags = btrfs_super_compat_flags(super_block);
@ -5427,7 +5433,11 @@ static int btrfs_ioctl_set_features(struct file *file, void __user *arg)
btrfs_set_super_incompat_flags(super_block, newflags);
spin_unlock(&root->fs_info->super_lock);
return btrfs_commit_transaction(trans, root);
ret = btrfs_commit_transaction(trans, root);
out_drop_write:
mnt_drop_write_file(file);
return ret;
}
long btrfs_ioctl(struct file *file, unsigned int