nfsd: don't return an unhashed lock stateid after taking mutex

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commit dd257933fa upstream.

nfsd4_lock will take the st_mutex before working with the stateid it
gets, but between the time when we drop the cl_lock and take the mutex,
the stateid could become unhashed (a'la FREE_STATEID). If that happens
the lock stateid returned to the client will be forgotten.

Fix this by first moving the st_mutex acquisition into
lookup_or_create_lock_state. Then, have it check to see if the lock
stateid is still hashed after taking the mutex. If it's not, then put
the stateid and try the find/create again.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Tested-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Jeff Layton 2016-08-11 10:37:39 -04:00 • committed by Greg Kroah-Hartman

parent 6dfc20babd

commit 37cbe5b6d1

1 changed files with 20 additions and 5 deletions

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fs/nfsd/nfs4state.c

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