NFSv4: Ensure that file unlock requests don't conflict with state recovery
The unlock path is currently failing to take the nfs_client->cl_sem read
lock, and hence the recovery path may see locks disappear from underneath
it.
Also ensure that it takes the nfs_inode->rwsem read lock so that it there
is no conflict with delegation recalls.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index beade557..16c9fbd 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -849,9 +849,11 @@
static int nfs4_reclaim_locks(struct nfs4_state *state, const struct nfs4_state_recovery_ops *ops)
{
struct inode *inode = state->inode;
+ struct nfs_inode *nfsi = NFS_I(inode);
struct file_lock *fl;
int status = 0;
+ down_write(&nfsi->rwsem);
for (fl = inode->i_flock; fl != NULL; fl = fl->fl_next) {
if (!(fl->fl_flags & (FL_POSIX|FL_FLOCK)))
continue;
@@ -874,8 +876,10 @@
goto out_err;
}
}
+ up_write(&nfsi->rwsem);
return 0;
out_err:
+ up_write(&nfsi->rwsem);
return status;
}