From e9f7bee1df223dcf83743b46cb06c08d95497ec0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 8 Sep 2006 09:48:54 -0700 Subject: [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 Cc: Chuck Lever Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nfs/read.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) (limited to 'fs/nfs/read.c') diff --git a/fs/nfs/read.c b/fs/nfs/read.c index da9cf11c326f..7a9ee00e0c61 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -43,13 +43,15 @@ static mempool_t *nfs_rdata_mempool; #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 @@ static int nfs_readpage_sync(struct nfs_open_context *ctx, struct inode *inode, 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 @@ static int nfs_pagein_multi(struct list_head *head, struct inode *inode) 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 @@ static int nfs_pagein_one(struct list_head *head, struct inode *inode) 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; -- cgit v1.2.1