NFS: decode_dirent should use an xdr_stream
Convert nfs*xdr.c to use an xdr stream in decode_dirent. This will prevent a
kernel oops that has been occuring when reading a vmapped page.
Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index fd30f18..88cbcda 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -171,7 +171,7 @@
#define MAX_READDIR_ARRAY ((PAGE_SIZE - sizeof(struct nfs_cache_array)) / sizeof(struct nfs_cache_array_entry))
-typedef __be32 * (*decode_dirent_t)(__be32 *, struct nfs_entry *, int);
+typedef __be32 * (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int);
typedef struct {
struct file *file;
struct page *page;
@@ -357,13 +357,11 @@
/* Fill in an entry based on the xdr code stored in desc->page */
static
-int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, __be32 **ptr)
+int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct xdr_stream *stream)
{
- __be32 *p = *ptr;
- p = desc->decode(p, entry, desc->plus);
+ __be32 *p = desc->decode(stream, entry, desc->plus);
if (IS_ERR(p))
return PTR_ERR(p);
- *ptr = p;
entry->fattr->time_start = desc->timestamp;
entry->fattr->gencount = desc->gencount;
@@ -438,10 +436,23 @@
/* Perform conversion from xdr to cache array */
static
void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
- struct page *xdr_page, struct page *page)
+ struct page *xdr_page, struct page *page, unsigned int buflen)
{
+ struct xdr_stream stream;
+ struct xdr_buf buf;
__be32 *ptr = kmap(xdr_page);
- while (xdr_decode(desc, entry, &ptr) == 0) {
+
+ buf.head->iov_base = xdr_page;
+ buf.head->iov_len = buflen;
+ buf.tail->iov_len = 0;
+ buf.page_base = 0;
+ buf.page_len = 0;
+ buf.buflen = buf.head->iov_len;
+ buf.len = buf.head->iov_len;
+
+ xdr_init_decode(&stream, &buf, ptr);
+
+ while (xdr_decode(desc, entry, &stream) == 0) {
if (nfs_readdir_add_to_array(entry, page) == -1)
break;
if (desc->plus == 1)
@@ -458,6 +469,7 @@
struct file *file = desc->file;
struct nfs_cache_array *array;
int status = 0;
+ unsigned int array_size = 1;
entry.prev_cookie = 0;
entry.cookie = *desc->dir_cookie;
@@ -476,9 +488,10 @@
goto out_release_array;
do {
status = nfs_readdir_xdr_filler(xdr_page, desc, &entry, file, inode);
+
if (status < 0)
break;
- nfs_readdir_page_filler(desc, &entry, xdr_page, page);
+ nfs_readdir_page_filler(desc, &entry, xdr_page, page, array_size * PAGE_SIZE);
} while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
put_page(xdr_page);