tree 3ce7f36c074e37dd565b91490582c4a4902f2b18
parent 7c8903f6373f9abecf060bad53ca36bc4ac037f2
author Trond Myklebust <Trond.Myklebust@netapp.com> 1139953984 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1139962174 -0800

[PATCH] NLM: Fix the NLM_GRANTED callback checks

If 2 threads attached to the same process are blocking on different locks on
different files (maybe even on different servers) but have the same lock
arguments (i.e.  same offset+length - actually quite common, since most
processes try to lock the entire file) then the first GRANTED call that wakes
one up will also wake the other.

Currently when the NLM_GRANTED callback comes in, lockd walks the list of
blocked locks in search of a match to the lock that the NLM server has
granted.  Although it checks the lock pid, start and end, it fails to check
the filehandle and the server address.

By checking the filehandle and server IP address, we ensure that this only
happens if the locks truly are referencing the same file.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>