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d98f722725
I have evidence of an Linux NFS client getting NFS4ERR_BAD_SEQID to a v4.0 LOCK request to a Linux server (which had fixed the problem with RELEASE_LOCKOWNER bug fixed). The LOCK request presented a "new" lock owner so there are two seq ids in the request: that for the open file, and that for the new lock. Given the context I am confident that the new lock owner was reported to have the wrong seqid. As lock owner identifiers are reused, the server must still have a lock owner active which the client thinks is no longer active. I wasn't able to determine a root-cause but the simplest fix seems to be to ensure lock owners are always unique much as open owners are (thanks to a time stamp). The easiest way to ensure uniqueness is with a 64bit counter for each server. That will never cycle (if updated once a nanosecond the last 584 years. A single NFS server would not handle open/lock requests nearly that fast, and a Linux node is unlikely to have an uptime approaching that). This patch removes the 2 ida and instead uses a per-server atomic64_t to provide uniqueness. Note that the lock owner already encodes the id as 64 bits even though it is a 32bit value. So changing to a 64bit value does not change the encoding of the lock owner. The open owner encoding is now 4 bytes larger. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Anna Schumaker <anna.schumaker@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 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.