Commit 6f9449be authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix a soft lockup in the delegation recovery code 



Fix a soft lockup when NFS client delegation recovery is attempted
but the inode is in the process of being freed. When the
igrab(inode) call fails, and we have to restart the recovery process,
we need to ensure that we won't attempt to recover the same delegation
again.

Fixes: 45870d69 ("NFSv4.1: Test delegation stateids when server...")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 3453d570

fs/nfs/delegation.c

+12 −8
Original line number Diff line number Diff line
@@ -229,6 +229,8 @@ static struct inode *nfs_delegation_grab_inode(struct nfs_delegation *delegation 
	spin_lock(&delegation->lock);

	if (delegation->inode != NULL)

		inode = igrab(delegation->inode);

	if (!inode)

		set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags);

	spin_unlock(&delegation->lock);

	return inode;

}
@@ -944,10 +946,11 @@ restart: 
	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {

		list_for_each_entry_rcu(delegation, &server->delegations,

								super_list) {

			if (test_bit(NFS_DELEGATION_RETURNING,

						&delegation->flags))

				continue;

			if (test_bit(NFS_DELEGATION_NEED_RECLAIM,

			if (test_bit(NFS_DELEGATION_INODE_FREEING,

						&delegation->flags) ||

			    test_bit(NFS_DELEGATION_RETURNING,

						&delegation->flags) ||

			    test_bit(NFS_DELEGATION_NEED_RECLAIM,

						&delegation->flags) == 0)

				continue;

			if (!nfs_sb_active(server->super))
@@ -1053,10 +1056,11 @@ restart: 
	list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {

		list_for_each_entry_rcu(delegation, &server->delegations,

								super_list) {

			if (test_bit(NFS_DELEGATION_RETURNING,

						&delegation->flags))

				continue;

			if (test_bit(NFS_DELEGATION_TEST_EXPIRED,

			if (test_bit(NFS_DELEGATION_INODE_FREEING,

						&delegation->flags) ||

			    test_bit(NFS_DELEGATION_RETURNING,

						&delegation->flags) ||

			    test_bit(NFS_DELEGATION_TEST_EXPIRED,

						&delegation->flags) == 0)

				continue;

			if (!nfs_sb_active(server->super))

fs/nfs/delegation.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ enum { 
	NFS_DELEGATION_RETURNING,

	NFS_DELEGATION_REVOKED,

	NFS_DELEGATION_TEST_EXPIRED,

	NFS_DELEGATION_INODE_FREEING,

};



int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred,

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