nfs: prevent page allocator recursions with swap over NFS.

GFP_NOFS is _more_ permissive than GFP_NOIO in that it will initiate IO,
just not of any filesystem data.

The problem is that previously NOFS was correct because that avoids
recursion into the NFS code.  With swap-over-NFS, it is no longer correct
as swap IO can lead to this recursion.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 9ef8b3cf7fc7929d125c24de01cd868069e2e6b6..7de1646c4e6be0e89096536a4745c4d30d162732 100644 (file)
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -70,7 +70,7 @@ void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
 static inline struct nfs_page *
 nfs_page_alloc(void)
 {
-       struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_KERNEL);
+       struct nfs_page *p = kmem_cache_zalloc(nfs_page_cachep, GFP_NOIO);
        if (p)
                INIT_LIST_HEAD(&p->wb_list);
        return p;

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 974e9c2d31fdcfda9115cec2bb09ee61f0025af3..211ba6566772a5c0b17869c8c8a199d130d6c337 100644 (file)
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -52,7 +52,7 @@ static mempool_t *nfs_commit_mempool;
 
 struct nfs_commit_data *nfs_commitdata_alloc(void)
 {
-       struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
+       struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
 
        if (p) {
                memset(p, 0, sizeof(*p));
@@ -70,7 +70,7 @@ EXPORT_SYMBOL_GPL(nfs_commit_free);
 
 struct nfs_write_header *nfs_writehdr_alloc(void)
 {
-       struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
+       struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
 
        if (p) {
                struct nfs_pgio_header *hdr = &p->header;