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Commit 14abcb0b authored by Trond Myklebust's avatar Trond Myklebust
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NFSv4: Fix up mirror allocation 

There are a number of callers of nfs_pageio_complete() that want to
continue using the nfs_pageio_descriptor without needing to call
nfs_pageio_init() again. Examples include nfs_pageio_resend() and
nfs_pageio_cond_complete().

The problem is that nfs_pageio_complete() also calls
nfs_pageio_cleanup_mirroring(), which frees up the array of mirrors.
This can lead to writeback errors, in the next call to
nfs_pageio_setup_mirroring().

Fix by simply moving the allocation of the mirrors to
nfs_pageio_setup_mirroring().

Link: https://bugzilla.kernel.org/show_bug.cgi?id=196709


Reported-by: default avatarJianhongYin <yin-jianhong@163.com>
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent ef954844

fs/nfs/pagelist.c

+39 −34
Original line number Diff line number Diff line
@@ -714,9 +714,6 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
		     int io_flags,

		     gfp_t gfp_flags)

{

	struct nfs_pgio_mirror *new;

	int i;



	desc->pg_moreio = 0;

	desc->pg_inode = inode;

	desc->pg_ops = pg_ops;
@@ -732,22 +729,10 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
	desc->pg_mirror_count = 1;

	desc->pg_mirror_idx = 0;



	if (pg_ops->pg_get_mirror_count) {

		/* until we have a request, we don't have an lseg and no

		 * idea how many mirrors there will be */

		new = kcalloc(NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX,

			      sizeof(struct nfs_pgio_mirror), gfp_flags);

		desc->pg_mirrors_dynamic = new;

		desc->pg_mirrors = new;



		for (i = 0; i < NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX; i++)

			nfs_pageio_mirror_init(&desc->pg_mirrors[i], bsize);

	} else {

	desc->pg_mirrors_dynamic = NULL;

	desc->pg_mirrors = desc->pg_mirrors_static;

	nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);

}

}

EXPORT_SYMBOL_GPL(nfs_pageio_init);



/**
@@ -865,32 +850,52 @@ static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc) 
	return ret;

}



static struct nfs_pgio_mirror *

nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,

		unsigned int mirror_count)

{

	struct nfs_pgio_mirror *ret;

	unsigned int i;



	kfree(desc->pg_mirrors_dynamic);

	desc->pg_mirrors_dynamic = NULL;

	if (mirror_count == 1)

		return desc->pg_mirrors_static;

	ret = kmalloc_array(mirror_count, sizeof(*ret), GFP_NOFS);

	if (ret != NULL) {

		for (i = 0; i < mirror_count; i++)

			nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);

		desc->pg_mirrors_dynamic = ret;

	}

	return ret;

}



/*

 * nfs_pageio_setup_mirroring - determine if mirroring is to be used

 *				by calling the pg_get_mirror_count op

 */

static int nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,

static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,

				       struct nfs_page *req)

{

	int mirror_count = 1;



	if (!pgio->pg_ops->pg_get_mirror_count)

		return 0;

	unsigned int mirror_count = 1;



	if (pgio->pg_ops->pg_get_mirror_count)

		mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);

	if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)

		return;



	if (pgio->pg_error < 0)

		return pgio->pg_error;



	if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX)

		return -EINVAL;



	if (WARN_ON_ONCE(!pgio->pg_mirrors_dynamic))

		return -EINVAL;

	if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {

		pgio->pg_error = -EINVAL;

		return;

	}



	pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);

	if (pgio->pg_mirrors == NULL) {

		pgio->pg_error = -ENOMEM;

		pgio->pg_mirrors = pgio->pg_mirrors_static;

		mirror_count = 1;

	}

	pgio->pg_mirror_count = mirror_count;



	return 0;

}



/*