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authorSuresh Jayaraman <sjayaraman@suse.de>2010-09-23 08:55:58 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2010-09-23 08:55:58 -0400
commit5eebde23223aeb0ad2d9e3be6590ff8bbfab0fc2 (patch)
tree7cfabe0191855550292b0a0c9b317315dffb2a50 /fs/nfs/nfs4xdr.c
parent63185942c5f138c62de16b4cbc7eee494a58fea8 (diff)
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nfs: introduce mount option '-olocal_lock' to make locks local
NFS clients since 2.6.12 support flock locks by emulating fcntl byte-range locks. Due to this, some windows applications which seem to use both flock (share mode lock mapped as flock by Samba) and fcntl locks sequentially on the same file, can't lock as they falsely assume the file is already locked. The problem was reported on a setup with windows clients accessing excel files on a Samba exported share which is originally a NFS mount from a NetApp filer. Older NFS clients (< 2.6.12) did not see this problem as flock locks were considered local. To support legacy flock behavior, this patch adds a mount option "-olocal_lock=" which can take the following values: 'none' - Neither flock locks nor POSIX locks are local 'flock' - flock locks are local 'posix' - fcntl/POSIX locks are local 'all' - Both flock locks and POSIX locks are local Testing: - This patch was tested by using -olocal_lock option with different values and the NLM calls were noted from the network packet captured. 'none' - NLM calls were seen during both flock() and fcntl(), flock lock was granted, fcntl was denied 'flock' - no NLM calls for flock(), NLM call was seen for fcntl(), granted 'posix' - NLM call was seen for flock() - granted, no NLM call for fcntl() 'all' - no NLM calls were seen during both flock() and fcntl() - No bugs were seen during NFSv4 locking/unlocking in general and NFSv4 reboot recovery. Cc: Neil Brown <neilb@suse.de> Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/nfs4xdr.c')
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