40144e49ff
Hole puching currently evicts pages from page cache and then goes on to remove blocks from the inode. This happens under both XFS_IOLOCK_EXCL and XFS_MMAPLOCK_EXCL which provides appropriate serialization with racing reads or page faults. However there is currently nothing that prevents readahead triggered by fadvise() or madvise() from racing with the hole punch and instantiating page cache page after hole punching has evicted page cache in xfs_flush_unmap_range() but before it has removed blocks from the inode. This page cache page will be mapping soon to be freed block and that can lead to returning stale data to userspace or even filesystem corruption. Fix the problem by protecting handling of readahead requests by XFS_IOLOCK_SHARED similarly as we protect reads. CC: stable@vger.kernel.org Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxjQNmxqmtA_VbYW0Su9rKRk2zobJmahcyeaEVOFKVQ5dw@mail.gmail.com/ Reported-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
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.