NFSv4.1: Fix a race in pNFS layoutcommit
Trond Myklebust authored
commit a073dbff

 upstream.

We need to clear the NFS_LSEG_LAYOUTCOMMIT bits atomically with the
NFS_INO_LAYOUTCOMMIT bit, otherwise we may end up with situations
where the two are out of sync.
The first half of the problem is to ensure that pnfs_layoutcommit_inode
clears the NFS_LSEG_LAYOUTCOMMIT bit through pnfs_list_write_lseg.
We still need to keep the reference to those segments until the RPC call
is finished, so in order to make it clear _where_ those references come
from, we add a helper pnfs_list_write_lseg_done() that cleans up after
pnfs_list_write_lseg.
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: default avatarBenny Halevy <bhalevy@tonian.com>
[bwh: Backported to 3.2: s/pnfs_put_lseg/put_lseg/]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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