[PATCH] NFS: large non-page-aligned direct I/O clobbers memory
The logic in nfs_direct_read_schedule and nfs_direct_write_schedule can
allow data->npages to be one larger than rpages. This causes a page
pointer to be written beyond the end of the pagevec in nfs_read_data (or
nfs_write_data).
Fix this by making nfs_(read|write)_alloc() calculate the size of the
pagevec array, and initialise data->npages.
Also get rid of the redundant argument to nfs_commit_alloc().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index da9cf11..7a9ee00 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -43,13 +43,15 @@
#define MIN_POOL_READ (32)
-struct nfs_read_data *nfs_readdata_alloc(unsigned int pagecount)
+struct nfs_read_data *nfs_readdata_alloc(size_t len)
{
+ unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
struct nfs_read_data *p = mempool_alloc(nfs_rdata_mempool, SLAB_NOFS);
if (p) {
memset(p, 0, sizeof(*p));
INIT_LIST_HEAD(&p->pages);
+ p->npages = pagecount;
if (pagecount <= ARRAY_SIZE(p->page_array))
p->pagevec = p->page_array;
else {
@@ -140,7 +142,7 @@
int result;
struct nfs_read_data *rdata;
- rdata = nfs_readdata_alloc(1);
+ rdata = nfs_readdata_alloc(count);
if (!rdata)
return -ENOMEM;
@@ -336,25 +338,25 @@
struct nfs_page *req = nfs_list_entry(head->next);
struct page *page = req->wb_page;
struct nfs_read_data *data;
- unsigned int rsize = NFS_SERVER(inode)->rsize;
- unsigned int nbytes, offset;
+ size_t rsize = NFS_SERVER(inode)->rsize, nbytes;
+ unsigned int offset;
int requests = 0;
LIST_HEAD(list);
nfs_list_remove_request(req);
nbytes = req->wb_bytes;
- for(;;) {
- data = nfs_readdata_alloc(1);
+ do {
+ size_t len = min(nbytes,rsize);
+
+ data = nfs_readdata_alloc(len);
if (!data)
goto out_bad;
INIT_LIST_HEAD(&data->pages);
list_add(&data->pages, &list);
requests++;
- if (nbytes <= rsize)
- break;
- nbytes -= rsize;
- }
+ nbytes -= len;
+ } while(nbytes != 0);
atomic_set(&req->wb_complete, requests);
ClearPageError(page);
@@ -402,7 +404,7 @@
if (NFS_SERVER(inode)->rsize < PAGE_CACHE_SIZE)
return nfs_pagein_multi(head, inode);
- data = nfs_readdata_alloc(NFS_SERVER(inode)->rpages);
+ data = nfs_readdata_alloc(NFS_SERVER(inode)->rsize);
if (!data)
goto out_bad;
