Commit 515dcdcd authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: nfsiod should not block forever in mempool_alloc() 



The concern is that since nfsiod is sometimes required to kick off a
commit, it can get locked up waiting forever in mempool_alloc() instead
of failing gracefully and leaving the commit until later.

Try to allocate from the slab first, with GFP_KERNEL | __GFP_NORETRY,
then fall back to a non-blocking attempt to allocate from the memory
pool.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent b2648015

fs/nfs/internal.h

+7 −0
Original line number Diff line number Diff line
@@ -587,6 +587,13 @@ nfs_write_match_verf(const struct nfs_writeverf *verf, 
		!nfs_write_verifier_cmp(&req->wb_verf, &verf->verifier);

}



static inline gfp_t nfs_io_gfp_mask(void)

{

	if (current->flags & PF_WQ_WORKER)

		return GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;

	return GFP_KERNEL;

}



/* unlink.c */

extern struct rpc_task *

nfs_async_rename(struct inode *old_dir, struct inode *new_dir,

fs/nfs/pnfs_nfs.c

+6 −2
Original line number Diff line number Diff line
@@ -419,7 +419,7 @@ static struct nfs_commit_data * 
pnfs_bucket_fetch_commitdata(struct pnfs_commit_bucket *bucket,

			     struct nfs_commit_info *cinfo)

{

	struct nfs_commit_data *data = nfs_commitdata_alloc(false);

	struct nfs_commit_data *data = nfs_commitdata_alloc();



	if (!data)

		return NULL;
@@ -515,7 +515,11 @@ pnfs_generic_commit_pagelist(struct inode *inode, struct list_head *mds_pages, 
	unsigned int nreq = 0;



	if (!list_empty(mds_pages)) {

		data = nfs_commitdata_alloc(true);

		data = nfs_commitdata_alloc();

		if (!data) {

			nfs_retry_commit(mds_pages, NULL, cinfo, -1);

			return -ENOMEM;

		}

		data->ds_commit_index = -1;

		list_splice_init(mds_pages, &data->pages);

		list_add_tail(&data->list, &list);

fs/nfs/write.c

+9 −15
Original line number Diff line number Diff line
@@ -70,27 +70,17 @@ static mempool_t *nfs_wdata_mempool; 
static struct kmem_cache *nfs_cdata_cachep;

static mempool_t *nfs_commit_mempool;



struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail)

struct nfs_commit_data *nfs_commitdata_alloc(void)

{

	struct nfs_commit_data *p;



	if (never_fail)

		p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);

	else {

		/* It is OK to do some reclaim, not no safe to wait

		 * for anything to be returned to the pool.

		 * mempool_alloc() cannot handle that particular combination,

		 * so we need two separate attempts.

		 */

	p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());

	if (!p) {

		p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);

		if (!p)

			p = kmem_cache_alloc(nfs_cdata_cachep, GFP_NOIO |

					     __GFP_NOWARN | __GFP_NORETRY);

		if (!p)

			return NULL;

	}



		memset(p, 0, sizeof(*p));

	}

	INIT_LIST_HEAD(&p->pages);

	return p;

}
@@ -1826,7 +1816,11 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how, 
	if (list_empty(head))

		return 0;



	data = nfs_commitdata_alloc(true);

	data = nfs_commitdata_alloc();

	if (!data) {

		nfs_retry_commit(head, NULL, cinfo, -1);

		return -ENOMEM;

	}



	/* Set up the argument struct */

	nfs_init_commit(data, head, NULL, cinfo);

include/linux/nfs_fs.h

+1 −1
Original line number Diff line number Diff line
@@ -580,7 +580,7 @@ extern int nfs_wb_all(struct inode *inode); 
extern int nfs_wb_page(struct inode *inode, struct page *page);

extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);

extern int  nfs_commit_inode(struct inode *, int);

extern struct nfs_commit_data *nfs_commitdata_alloc(bool never_fail);

extern struct nfs_commit_data *nfs_commitdata_alloc(void);

extern void nfs_commit_free(struct nfs_commit_data *data);

bool nfs_commit_end(struct nfs_mds_commit_info *cinfo);