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NFS: Use GFP_NOIO for two allocations in writeback

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

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: 00bfa30abe ("NFS: Create a common pgio_alloc and pgio_release...")
Cc: stable@vger.kernel.org # 3.16+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Benjamin Coddington 2017-04-19 10:11:33 -04:00 committed by Trond Myklebust
parent 1f84ccdf37
commit ae97aa524e
1 changed files with 11 additions and 4 deletions
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15
fs/nfs/pagelist.c
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@ -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;