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1c9be84a90
Use ->d_seq instead of grabbing ->d_lock; in case of shortname dentries that avoids any stores to shared data objects and in case of long names we are down to (unavoidable) atomic_inc on the external_name refcount. Makes the thing safer as well - the areas where ->d_seq is held odd are all nested inside the areas where ->d_lock is held, and the latter are much more numerous. NOTE: now that there is a lockless path where we might try to grab a reference to an already doomed external_name instance, it is no longer possible for external_name.u.count and external_name.u.head to share space (kudos to Linus for spotting that). To reduce the noise this commit just make external_name.u a struct (instead of union); the next commit will dissolve it. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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.