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NFS: Fix a couple of regressions in readdir.
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Fix up the issue that array->eof_index needs to be able to be set
even if array->size == 0.

Ensure that we catch all important memory allocation error conditions
and/or kmap() failures.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
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Trond Myklebust authored and Trond Myklebust committed Nov 16, 2010
1 parent 23ebbd9 commit 8cd51a0
Showing 1 changed file with 56 additions and 34 deletions.
90 changes: 56 additions & 34 deletions fs/nfs/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -194,9 +194,13 @@ typedef struct {
static
struct nfs_cache_array *nfs_readdir_get_array(struct page *page)
{
void *ptr;
if (page == NULL)
return ERR_PTR(-EIO);
return (struct nfs_cache_array *)kmap(page);
ptr = kmap(page);
if (ptr == NULL)
return ERR_PTR(-ENOMEM);
return ptr;
}

static
Expand All @@ -213,6 +217,9 @@ int nfs_readdir_clear_array(struct page *page, gfp_t mask)
{
struct nfs_cache_array *array = nfs_readdir_get_array(page);
int i;

if (IS_ERR(array))
return PTR_ERR(array);
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
nfs_readdir_release_array(page);
Expand Down Expand Up @@ -244,7 +251,7 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)

if (IS_ERR(array))
return PTR_ERR(array);
ret = -EIO;
ret = -ENOSPC;
if (array->size >= MAX_READDIR_ARRAY)
goto out;

Expand All @@ -255,9 +262,9 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
if (ret)
goto out;
array->last_cookie = entry->cookie;
array->size++;
if (entry->eof == 1)
array->eof_index = array->size;
array->size++;
out:
nfs_readdir_release_array(page);
return ret;
Expand All @@ -272,7 +279,7 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
if (diff < 0)
goto out_eof;
if (diff >= array->size) {
if (array->eof_index > 0)
if (array->eof_index >= 0)
goto out_eof;
desc->current_index += array->size;
return -EAGAIN;
Expand All @@ -281,8 +288,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
index = (unsigned int)diff;
*desc->dir_cookie = array->array[index].cookie;
desc->cache_entry_index = index;
if (index == array->eof_index)
desc->eof = 1;
return 0;
out_eof:
desc->eof = 1;
Expand All @@ -296,17 +301,17 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
int status = -EAGAIN;

for (i = 0; i < array->size; i++) {
if (i == array->eof_index) {
desc->eof = 1;
status = -EBADCOOKIE;
}
if (array->array[i].cookie == *desc->dir_cookie) {
desc->cache_entry_index = i;
status = 0;
break;
goto out;
}
}

if (i == array->eof_index) {
desc->eof = 1;
status = -EBADCOOKIE;
}
out:
return status;
}

Expand Down Expand Up @@ -449,7 +454,7 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)

/* Perform conversion from xdr to cache array */
static
void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
void *xdr_page, struct page *page, unsigned int buflen)
{
struct xdr_stream stream;
Expand All @@ -471,21 +476,29 @@ void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *e

do {
status = xdr_decode(desc, entry, &stream);
if (status != 0)
if (status != 0) {
if (status == -EAGAIN)
status = 0;
break;
}

if (nfs_readdir_add_to_array(entry, page) == -1)
break;
if (desc->plus == 1)
nfs_prime_dcache(desc->file->f_path.dentry, entry);

status = nfs_readdir_add_to_array(entry, page);
if (status != 0)
break;
} while (!entry->eof);

if (status == -EBADCOOKIE && entry->eof) {
array = nfs_readdir_get_array(page);
array->eof_index = array->size - 1;
status = 0;
nfs_readdir_release_array(page);
if (!IS_ERR(array)) {
array->eof_index = array->size;
status = 0;
nfs_readdir_release_array(page);
}
}
return status;
}

static
Expand Down Expand Up @@ -537,7 +550,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
struct nfs_entry entry;
struct file *file = desc->file;
struct nfs_cache_array *array;
int status = 0;
int status = -ENOMEM;
unsigned int array_size = ARRAY_SIZE(pages);

entry.prev_cookie = 0;
Expand All @@ -549,6 +562,10 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
goto out;

array = nfs_readdir_get_array(page);
if (IS_ERR(array)) {
status = PTR_ERR(array);
goto out;
}
memset(array, 0, sizeof(struct nfs_cache_array));
array->eof_index = -1;

Expand All @@ -560,8 +577,13 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,

if (status < 0)
break;
nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
} while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
status = nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
if (status < 0) {
if (status == -ENOSPC)
status = 0;
break;
}
} while (array->eof_index < 0);

nfs_readdir_free_large_page(pages_ptr, pages, array_size);
out_release_array:
Expand All @@ -582,8 +604,10 @@ static
int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
{
struct inode *inode = desc->file->f_path.dentry->d_inode;
int ret;

if (nfs_readdir_xdr_to_array(desc, page, inode) < 0)
ret = nfs_readdir_xdr_to_array(desc, page, inode);
if (ret < 0)
goto error;
SetPageUptodate(page);

Expand All @@ -595,7 +619,7 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
return 0;
error:
unlock_page(page);
return -EIO;
return ret;
}

static
Expand All @@ -608,12 +632,8 @@ void cache_page_release(nfs_readdir_descriptor_t *desc)
static
struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
{
struct page *page;
page = read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
return read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
desc->page_index, (filler_t *)nfs_readdir_filler, desc);
if (IS_ERR(page))
desc->eof = 1;
return page;
}

/*
Expand All @@ -639,8 +659,10 @@ int find_cache_page(nfs_readdir_descriptor_t *desc)
static inline
int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
{
int res = -EAGAIN;
int res;

if (desc->page_index == 0)
desc->current_index = 0;
while (1) {
res = find_cache_page(desc);
if (res != -EAGAIN)
Expand Down Expand Up @@ -670,6 +692,8 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
struct dentry *dentry = NULL;

array = nfs_readdir_get_array(desc->page);
if (IS_ERR(array))
return PTR_ERR(array);

for (i = desc->cache_entry_index; i < array->size; i++) {
d_type = DT_UNKNOWN;
Expand All @@ -685,11 +709,9 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
*desc->dir_cookie = array->array[i+1].cookie;
else
*desc->dir_cookie = array->last_cookie;
if (i == array->eof_index) {
desc->eof = 1;
break;
}
}
if (i == array->eof_index)
desc->eof = 1;

nfs_readdir_release_array(desc->page);
cache_page_release(desc);
Expand Down

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