Commit 7f27392c authored by Trond Myklebust's avatar Trond Myklebust
Browse files

pNFS: Fix races between return-on-close and layoutreturn. 



If one or more of the layout segments reports an error during I/O, then
we may have to send a layoutreturn to report the error back to the NFS
metadata server.
This patch ensures that the return-on-close code can detect the
outstanding layoutreturn, and not preempt it.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent df9cecc1

fs/nfs/nfs4proc.c

+0 −2
Original line number Diff line number Diff line
@@ -7972,8 +7972,6 @@ static void nfs4_layoutreturn_release(void *calldata) 
		pnfs_set_layout_stateid(lo, &lrp->res.stateid, true);

	pnfs_mark_matching_lsegs_invalid(lo, &freeme, &lrp->args.range);

	pnfs_clear_layoutreturn_waitbit(lo);

	clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE, &lo->plh_flags);

	rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);

	lo->plh_block_lgets--;

	spin_unlock(&lo->plh_inode->i_lock);

	pnfs_free_lseg_list(&freeme);

fs/nfs/pnfs.c

+35 −28
Original line number Diff line number Diff line
@@ -352,7 +352,7 @@ pnfs_layout_need_return(struct pnfs_layout_hdr *lo, 
{

	struct pnfs_layout_segment *s;



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

	if (!test_and_clear_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))

		return false;



	list_for_each_entry(s, &lo->plh_segs, pls_list)
@@ -362,6 +362,18 @@ pnfs_layout_need_return(struct pnfs_layout_hdr *lo, 
	return true;

}



static bool

pnfs_prepare_layoutreturn(struct pnfs_layout_hdr *lo)

{

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

		return false;

	lo->plh_return_iomode = 0;

	lo->plh_block_lgets++;

	pnfs_get_layout_hdr(lo);

	clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE, &lo->plh_flags);

	return true;

}



static void pnfs_layoutreturn_before_put_lseg(struct pnfs_layout_segment *lseg,

		struct pnfs_layout_hdr *lo, struct inode *inode)

{
@@ -372,17 +384,16 @@ static void pnfs_layoutreturn_before_put_lseg(struct pnfs_layout_segment *lseg, 
	if (pnfs_layout_need_return(lo, lseg)) {

		nfs4_stateid stateid;

		enum pnfs_iomode iomode;

		bool send;



		stateid = lo->plh_stateid;

		iomode = lo->plh_return_iomode;

		/* decreased in pnfs_send_layoutreturn() */

		lo->plh_block_lgets++;

		lo->plh_return_iomode = 0;

		send = pnfs_prepare_layoutreturn(lo);

		spin_unlock(&inode->i_lock);

		pnfs_get_layout_hdr(lo);



		if (send) {

			/* Send an async layoutreturn so we dont deadlock */

			pnfs_send_layoutreturn(lo, stateid, iomode, false);

		}

	} else

		spin_unlock(&inode->i_lock);

}
@@ -924,6 +935,7 @@ void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo) 
	clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);

	smp_mb__after_atomic();

	wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);

	rpc_wake_up(&NFS_SERVER(lo->plh_inode)->roc_rpcwaitq);

}



static int
@@ -978,6 +990,7 @@ _pnfs_return_layout(struct inode *ino) 
	LIST_HEAD(tmp_list);

	nfs4_stateid stateid;

	int status = 0, empty;

	bool send;



	dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
@@ -1007,17 +1020,18 @@ _pnfs_return_layout(struct inode *ino) 
	/* Don't send a LAYOUTRETURN if list was initially empty */

	if (empty) {

		spin_unlock(&ino->i_lock);

		pnfs_put_layout_hdr(lo);

		dprintk("NFS: %s no layout segments to return\n", __func__);

		goto out;

		goto out_put_layout_hdr;

	}



	set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);

	lo->plh_block_lgets++;

	send = pnfs_prepare_layoutreturn(lo);

	spin_unlock(&ino->i_lock);

	pnfs_free_lseg_list(&tmp_list);



	if (send)

		status = pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, true);

out_put_layout_hdr:

	pnfs_put_layout_hdr(lo);

out:

	dprintk("<-- %s status: %d\n", __func__, status);

	return status;
@@ -1097,13 +1111,9 @@ bool pnfs_roc(struct inode *ino) 
out_noroc:

	if (lo) {

		stateid = lo->plh_stateid;

		layoutreturn =

			test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,

					   &lo->plh_flags);

		if (layoutreturn) {

			lo->plh_block_lgets++;

			pnfs_get_layout_hdr(lo);

		}

		if (test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,

					   &lo->plh_flags))

			layoutreturn = pnfs_prepare_layoutreturn(lo);

	}

	spin_unlock(&ino->i_lock);

	if (layoutreturn) {
@@ -1163,16 +1173,14 @@ 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;

	layoutreturn = test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,

					   &lo->plh_flags);

	if (layoutreturn) {

		lo->plh_block_lgets++;

		pnfs_get_layout_hdr(lo);

	}

	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) {

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

		pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, false);

		return true;

	}
@@ -1693,7 +1701,6 @@ void pnfs_error_mark_layout_for_return(struct inode *inode, 
	spin_lock(&inode->i_lock);

	/* set failure bit so that pnfs path will be retried later */

	pnfs_layout_set_fail_bit(lo, iomode);

	set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);

	if (lo->plh_return_iomode == 0)

		lo->plh_return_iomode = range.iomode;

	else if (lo->plh_return_iomode != range.iomode)

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