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It's possible that the dentry cache can tell us the parent of a directory. Therefore, when repairing directory dot dot entries, query the dcache as a last resort before scanning the entire filesystem. A reviewer asks: "How high is the chance that we actually have a valid dcache entry for a file in a corrupted directory?" There's a decent chance of this actually working. Say you have a 1000-block directory foo, and block 980 gets corrupted. Let's further suppose that block 0 has a correct entry for ".." and "bar". If someone accesses /mnt/foo/bar, that will cause the dcache to create a dentry from /mnt to /mnt/foo whose d_parent points back to /mnt. If you then want to rebuild the directory, XFS can obtain the parent from the dcache without needing to wander into parent pointers or scan the filesystem to find /mnt's connection to foo. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
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 reStructuredText 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.