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commit bf7ba8ee759b7b7a34787ddd8dc3f190a3d7fa24 upstream. We are hitting the following deadlock in production occasionally Task 1 Task 2 Task 3 Task 4 Task 5 fsync(A) start trans start commit falloc(A) lock 5m-10m start trans wait for commit fiemap(A) lock 0-10m wait for 5m-10m (have 0-5m locked) have btrfs_need_log_full_commit !full_sync wait_ordered_extents finish_ordered_io(A) lock 0-5m DEADLOCK We have an existing dependency of file extent lock -> transaction. However in fsync if we tried to do the fast logging, but then had to fall back to committing the transaction, we will be forced to call btrfs_wait_ordered_range() to make sure all of our extents are updated. This creates a dependency of transaction -> file extent lock, because btrfs_finish_ordered_io() will need to take the file extent lock in order to run the ordered extents. Fix this by stopping the transaction if we have to do the full commit and we attempted to do the fast logging. Then attach to the transaction and commit it if we need to. CC: stable@vger.kernel.org # 5.15+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.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.