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Commit ae97aa52 authored by Benjamin Coddington's avatar Benjamin Coddington Committed by Trond Myklebust
Browse files

NFS: Use GFP_NOIO for two allocations in writeback 



Prevent a deadlock that can occur if we wait on allocations
that try to write back our pages.

Signed-off-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Fixes: 00bfa30a ("NFS: Create a common pgio_alloc and pgio_release...")
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 1f84ccdf

fs/nfs/pagelist.c

+11 −4
Original line number Diff line number Diff line
@@ -29,13 +29,14 @@ 
static struct kmem_cache *nfs_page_cachep;

static const struct rpc_call_ops nfs_pgio_common_ops;



static bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount)

static bool nfs_pgarray_set(struct nfs_page_array *p, unsigned int pagecount,

					gfp_t gfp_flags)

{

	p->npages = pagecount;

	if (pagecount <= ARRAY_SIZE(p->page_array))

		p->pagevec = p->page_array;

	else {

		p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_KERNEL);

		p->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);

		if (!p->pagevec)

			p->npages = 0;

	}
@@ -681,6 +682,7 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
{

	struct nfs_pgio_mirror *new;

	int i;

	gfp_t gfp_flags = GFP_KERNEL;



	desc->pg_moreio = 0;

	desc->pg_inode = inode;
@@ -700,8 +702,10 @@ void nfs_pageio_init(struct nfs_pageio_descriptor *desc, 
	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 */

		if (desc->pg_rw_ops->rw_mode == FMODE_WRITE)

			gfp_flags = GFP_NOIO;

		new = kcalloc(NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX,

			      sizeof(struct nfs_pgio_mirror), GFP_KERNEL);

			      sizeof(struct nfs_pgio_mirror), gfp_flags);

		desc->pg_mirrors_dynamic = new;

		desc->pg_mirrors = new;
@@ -755,9 +759,12 @@ int nfs_generic_pgio(struct nfs_pageio_descriptor *desc, 
	struct list_head *head = &mirror->pg_list;

	struct nfs_commit_info cinfo;

	unsigned int pagecount, pageused;

	gfp_t gfp_flags = GFP_KERNEL;



	pagecount = nfs_page_array_len(mirror->pg_base, mirror->pg_count);

	if (!nfs_pgarray_set(&hdr->page_array, pagecount)) {

	if (desc->pg_rw_ops->rw_mode == FMODE_WRITE)

		gfp_flags = GFP_NOIO;

	if (!nfs_pgarray_set(&hdr->page_array, pagecount, gfp_flags)) {

		nfs_pgio_error(hdr);

		desc->pg_error = -ENOMEM;

		return desc->pg_error;