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Commit 86dfbc17 authored by Trond Myklebust's avatar Trond Myklebust Committed by Sasha Levin
Browse files

pNFS/flexfiles: Fix list corruption if the mirror count changes 



commit 8b04013737341442ed914b336cde866b902664ae upstream.

If the mirror count changes in the new layout we pick up inside
ff_layout_pg_init_write(), then we can end up adding the
request to the wrong mirror and corrupting the mirror->pg_list.

Fixes: d600ad1f ("NFS41: pop some layoutget errors to application")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a20cecec

fs/nfs/flexfilelayout/flexfilelayout.c

+7 −4
Original line number Diff line number Diff line
@@ -939,9 +939,8 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio, 
		goto out_mds;



	/* Use a direct mapping of ds_idx to pgio mirror_idx */

	if (WARN_ON_ONCE(pgio->pg_mirror_count !=

	    FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg)))

		goto out_mds;

	if (pgio->pg_mirror_count != FF_LAYOUT_MIRROR_COUNT(pgio->pg_lseg))

		goto out_eagain;



	for (i = 0; i < pgio->pg_mirror_count; i++) {

		ds = nfs4_ff_layout_prepare_ds(pgio->pg_lseg, i, true);
@@ -960,11 +959,15 @@ ff_layout_pg_init_write(struct nfs_pageio_descriptor *pgio, 
	}



	return;



out_eagain:

	pnfs_generic_pg_cleanup(pgio);

	pgio->pg_error = -EAGAIN;

	return;

out_mds:

	pnfs_put_lseg(pgio->pg_lseg);

	pgio->pg_lseg = NULL;

	nfs_pageio_reset_write_mds(pgio);

	pgio->pg_error = -EAGAIN;

}



static unsigned int