pnfs: change layout state seqlock to a spinlock

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This prepares for future changes, where the layout state needs
to change atomically with several other variables.  In particular,
it will need to know if lo->segs is empty, as we test that instead
of manipulating the NFS_LAYOUT_STATEID_SET bit.  Moreover, the
layoutstateid is not really a read-mostly structure, as it is
written almost as often as it is read.

The behavior of pnfs_get_layout_stateid is also slightly changed, so that
it no longer changes the stateid.  Its name is changed to +pnfs_choose_layoutget_stateid.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

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Fred Isaman 2011-01-06 11:36:22 +00:00 • committed by Trond Myklebust

parent b7edfaa198

commit fd6002e9b8

3 changed files with 27 additions and 61 deletions

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2

fs/nfs/nfs4xdr.c

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77

fs/nfs/pnfs.c

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7

fs/nfs/pnfs.h

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