ac3a513d4f
[ Upstream commit 5bab56fff53ce161ed859d9559a10361d4f79578 ]
When swap is activated to a file on an NFSv4 mount we arrange that the
state manager thread is always present as starting a new thread requires
memory allocations that might block waiting for swap.
Unfortunately the code for allowing the state manager thread to exit when
swap is disabled was not tested properly and does not work.
This can be seen by examining /proc/fs/nfsfs/servers after disabling swap
and unmounting the filesystem. The servers file will still list one
entry. Also a "ps" listing will show the state manager thread is still
present.
There are two problems.
1/ rpc_clnt_swap_deactivate() doesn't walk up the ->cl_parent list to
find the primary client on which the state manager runs.
2/ The thread is not woken up properly and it immediately goes back to
sleep without checking whether it is really needed. Using
nfs4_schedule_state_manager() ensures a proper wake-up.
Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: 4dc73c679114 ("NFSv4: keep state manager thread active if swap is enabled")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sashal@kernel.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.