Commit 4ff376fe authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFSv4.1/pnfs: Fix a close/delegreturn hang when return-on-close is set 



The helper pnfs_roc() has already verified that we have no delegations,
and no further open files, hence no outstanding I/O and it has marked
all the return-on-close lsegs as being invalid.
Furthermore, it sets the NFS_LAYOUT_RETURN bit, thus serialising the
close/delegreturn with all future layoutget calls on this inode.

The checks in pnfs_roc_drain() for valid layout segments are therefore
redundant: those cannot exist until another layoutget completes.
The other check for whether or not NFS_LAYOUT_RETURN is set, actually
causes a hang, since we already know that we hold that flag.

To fix, we therefore strip out all the functionality in pnfs_roc_drain()
except the retrieval of the barrier state, and then rename the function
accordingly.

Reported-by: default avatarChristoph Hellwig <hch@infradead.org>
Fixes: 5c4a79fb ("Don't prevent layoutgets when doing return-on-close")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 7e94d6c4

fs/nfs/nfs4proc.c

+4 −8
Original line number Diff line number Diff line
@@ -2737,11 +2737,8 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data) 


	if (calldata->arg.fmode == 0) {

		task->tk_msg.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_CLOSE];

		if (calldata->roc &&

		    pnfs_roc_drain(inode, &calldata->roc_barrier, task)) {

			nfs_release_seqid(calldata->arg.seqid);

			goto out_wait;

		    }

		if (calldata->roc)

			pnfs_roc_get_barrier(inode, &calldata->roc_barrier);

	}

	calldata->arg.share_access =

		nfs4_map_atomic_open_share(NFS_SERVER(inode),
@@ -5289,9 +5286,8 @@ static void nfs4_delegreturn_prepare(struct rpc_task *task, void *data) 


	d_data = (struct nfs4_delegreturndata *)data;



	if (d_data->roc &&

	    pnfs_roc_drain(d_data->inode, &d_data->roc_barrier, task))

		return;

	if (d_data->roc)

		pnfs_roc_get_barrier(d_data->inode, &d_data->roc_barrier);



	nfs4_setup_sequence(d_data->res.server,

			&d_data->args.seq_args,

fs/nfs/pnfs.c

+1 −23
Original line number Diff line number Diff line
@@ -1141,25 +1141,14 @@ void pnfs_roc_set_barrier(struct inode *ino, u32 barrier) 
	spin_unlock(&ino->i_lock);

}



bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task)

void pnfs_roc_get_barrier(struct inode *ino, u32 *barrier)

{

	struct nfs_inode *nfsi = NFS_I(ino);

	struct pnfs_layout_hdr *lo;

	struct pnfs_layout_segment *lseg;

	nfs4_stateid stateid;

	u32 current_seqid;

	bool layoutreturn = false;



	spin_lock(&ino->i_lock);

	list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list) {

		if (!test_bit(NFS_LSEG_ROC, &lseg->pls_flags))

			continue;

		if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags))

			continue;

		rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);

		spin_unlock(&ino->i_lock);

		return true;

	}

	lo = nfsi->layout;

	current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
@@ -1168,18 +1157,7 @@ bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task) 
	 */

	*barrier = current_seqid + atomic_read(&lo->plh_outstanding);

	stateid = lo->plh_stateid;

	if (test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,

					   &lo->plh_flags))

		layoutreturn = pnfs_prepare_layoutreturn(lo);

	if (test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags))

		rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);



	spin_unlock(&ino->i_lock);

	if (layoutreturn) {

		pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, false);

		return true;

	}

	return false;

}



/*

fs/nfs/pnfs.h

+3 −4
Original line number Diff line number Diff line
@@ -267,7 +267,7 @@ int pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo, 
bool pnfs_roc(struct inode *ino);

void pnfs_roc_release(struct inode *ino);

void pnfs_roc_set_barrier(struct inode *ino, u32 barrier);

bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task);

void pnfs_roc_get_barrier(struct inode *ino, u32 *barrier);

void pnfs_set_layoutcommit(struct inode *, struct pnfs_layout_segment *, loff_t);

void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data);

int pnfs_layoutcommit_inode(struct inode *inode, bool sync);
@@ -605,10 +605,9 @@ pnfs_roc_set_barrier(struct inode *ino, u32 barrier) 
{

}



static inline bool

pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task)

static inline void

pnfs_roc_get_barrier(struct inode *ino, u32 *barrier)

{

	return false;

}



static inline void set_pnfs_layoutdriver(struct nfs_server *s,

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