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commit d49d3287e74ffe55ae7430d1e795e5f9bf7359ea upstream. If we have the following sequence of events btrfs sub create A btrfs sub create A/B btrfs sub snap A C mkdir C/foo mv A/B C/foo rm -rf * We will end up with a transaction abort. The reason for this is because we create a root ref for B pointing to A. When we create a snapshot of C we still have B in our tree, but because the root ref points to A and not C we will make it appear to be empty. The problem happens when we move B into C. This removes the root ref for B pointing to A and adds a ref of B pointing to C. When we rmdir C we'll see that we have a ref to our root and remove the root ref, despite not actually matching our reference name. Now btrfs_del_root_ref() allowing this to work is a bug as well, however we know that this inode does not actually point to a root ref in the first place, so we shouldn't be calling btrfs_del_root_ref() in the first place and instead simply look up our dir index for this item and do the rest of the removal. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.