[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>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index db9cbf68e12b..41e5a19199e9 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -729,7 +729,7 @@ struct nfs_read_data {
         struct list_head        pages;  /* Coalesced read requests */
         struct nfs_page         *req;   /* multi ops per nfs_page */
         struct page             **pagevec;
-        unsigned int            npages; /* active pages in pagevec */
+        unsigned int            npages; /* Max length of pagevec */
         struct nfs_readargs args;
         struct nfs_readres  res;
 #ifdef CONFIG_NFS_V4
@@ -748,7 +748,7 @@ struct nfs_write_data {
         struct list_head        pages;          /* Coalesced requests we wish to flush */
         struct nfs_page         *req;           /* multi ops per nfs_page */
         struct page             **pagevec;
-        unsigned int            npages;         /* active pages in pagevec */
+        unsigned int            npages;         /* Max length of pagevec */
         struct nfs_writeargs    args;           /* argument struct */
         struct nfs_writeres     res;            /* result struct */
 #ifdef CONFIG_NFS_V4