NFS: Fix a memory leak in nfs_readdir
We need to ensure that the entries in the nfs_cache_array get cleared
when the page is removed from the page cache. To do so, we use the
freepage address_space operation.
Change nfs_readdir_clear_array to use kmap_atomic(), so that the
function can be safely called from all contexts.
Finally, modify the cache_page_release helper to call
nfs_readdir_clear_array directly, when dealing with an anonymous
page from 'uncached_readdir'.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e03537f..d529e0e 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -57,7 +57,7 @@
struct inode *, struct dentry *);
static int nfs_fsync_dir(struct file *, int);
static loff_t nfs_llseek_dir(struct file *, loff_t, int);
-static int nfs_readdir_clear_array(struct page*, gfp_t);
+static void nfs_readdir_clear_array(struct page*);
const struct file_operations nfs_dir_operations = {
.llseek = nfs_llseek_dir,
@@ -83,8 +83,8 @@
.setattr = nfs_setattr,
};
-const struct address_space_operations nfs_dir_addr_space_ops = {
- .releasepage = nfs_readdir_clear_array,
+const struct address_space_operations nfs_dir_aops = {
+ .freepage = nfs_readdir_clear_array,
};
#ifdef CONFIG_NFS_V3
@@ -214,17 +214,15 @@
* we are freeing strings created by nfs_add_to_readdir_array()
*/
static
-int nfs_readdir_clear_array(struct page *page, gfp_t mask)
+void nfs_readdir_clear_array(struct page *page)
{
- struct nfs_cache_array *array = nfs_readdir_get_array(page);
+ struct nfs_cache_array *array;
int i;
- if (IS_ERR(array))
- return PTR_ERR(array);
+ array = kmap_atomic(page, KM_USER0);
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
- nfs_readdir_release_array(page);
- return 0;
+ kunmap_atomic(array, KM_USER0);
}
/*
@@ -639,6 +637,8 @@
static
void cache_page_release(nfs_readdir_descriptor_t *desc)
{
+ if (!desc->page->mapping)
+ nfs_readdir_clear_array(desc->page);
page_cache_release(desc->page);
desc->page = NULL;
}