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NFS: Fix a memory leak in nfs_readdir

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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>
This commit is contained in:
Trond Myklebust 2010-12-01 14:17:06 -05:00
parent 6072d13c42
commit 11de3b11e0
3 changed files with 11 additions and 9 deletions
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18
fs/nfs/dir.c
View File

@ -57,7 +57,7 @@ static int nfs_rename(struct inode *, struct dentry *,
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 @@ const struct inode_operations nfs_dir_inode_operations = {
.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 @@ void nfs_readdir_release_array(struct page *page)
* 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 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
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;
}

1
fs/nfs/inode.c
View File

@ -289,6 +289,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->dir_inode_ops;
inode->i_fop = &nfs_dir_operations;
inode->i_data.a_ops = &nfs_dir_aops;
if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS))
set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
/* Deal with crossing mountpoints */

1
include/linux/nfs_fs.h
View File

@ -401,6 +401,7 @@ extern const struct inode_operations nfs3_file_inode_operations;
#endif /* CONFIG_NFS_V3 */
extern const struct file_operations nfs_file_operations;
extern const struct address_space_operations nfs_file_aops;
extern const struct address_space_operations nfs_dir_aops;
static inline struct nfs_open_context *nfs_file_open_context(struct file *filp)
{