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NFS: Clean up directory array handling

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Refactor to use pagecache_get_page() so that we can fill the page
in multiple stages.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
This commit is contained in:
Trond Myklebust 2020-11-01 12:34:43 -05:00
parent 972bcdf233
commit 1f1d4aa4e4
1 changed files with 78 additions and 62 deletions
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140
fs/nfs/dir.c
View File

@ -149,7 +149,7 @@ typedef struct nfs_readdir_descriptor {
struct file *file;
struct page *page;
struct dir_context *ctx;
unsigned long page_index;
pgoff_t page_index;
u64 dir_cookie;
u64 last_cookie;
u64 dup_cookie;
@ -166,13 +166,18 @@ typedef struct nfs_readdir_descriptor {
bool eof;
} nfs_readdir_descriptor_t;
static
void nfs_readdir_init_array(struct page *page)
static void nfs_readdir_array_init(struct nfs_cache_array *array)
{
memset(array, 0, sizeof(struct nfs_cache_array));
}
static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie)
{
struct nfs_cache_array *array;
array = kmap_atomic(page);
memset(array, 0, sizeof(struct nfs_cache_array));
nfs_readdir_array_init(array);
array->last_cookie = last_cookie;
kunmap_atomic(array);
}
@ -188,7 +193,7 @@ void nfs_readdir_clear_array(struct page *page)
array = kmap_atomic(page);
for (i = 0; i < array->size; i++)
kfree(array->array[i].string.name);
array->size = 0;
nfs_readdir_array_init(array);
kunmap_atomic(array);
}
@ -268,6 +273,44 @@ out:
return ret;
}
static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
pgoff_t index, u64 last_cookie)
{
struct page *page;
page = grab_cache_page(mapping, index);
if (page && !PageUptodate(page)) {
nfs_readdir_page_init_array(page, last_cookie);
if (invalidate_inode_pages2_range(mapping, index + 1, -1) < 0)
nfs_zap_mapping(mapping->host, mapping);
SetPageUptodate(page);
}
return page;
}
static u64 nfs_readdir_page_last_cookie(struct page *page)
{
struct nfs_cache_array *array;
u64 ret;
array = kmap_atomic(page);
ret = array->last_cookie;
kunmap_atomic(array);
return ret;
}
static bool nfs_readdir_page_needs_filling(struct page *page)
{
struct nfs_cache_array *array;
bool ret;
array = kmap_atomic(page);
ret = !nfs_readdir_array_is_full(array);
kunmap_atomic(array);
return ret;
}
static void nfs_readdir_page_set_eof(struct page *page)
{
struct nfs_cache_array *array;
@ -682,10 +725,8 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
int status = -ENOMEM;
unsigned int array_size = ARRAY_SIZE(pages);
nfs_readdir_init_array(page);
entry.prev_cookie = 0;
entry.cookie = desc->last_cookie;
entry.cookie = nfs_readdir_page_last_cookie(page);
entry.eof = 0;
entry.fh = nfs_alloc_fhandle();
entry.fattr = nfs_alloc_fattr();
@ -730,48 +771,25 @@ out:
return status;
}
/*
* Now we cache directories properly, by converting xdr information
* to an array that can be used for lookups later. This results in
* fewer cache pages, since we can store more information on each page.
* We only need to convert from xdr once so future lookups are much simpler
*/
static
int nfs_readdir_filler(void *data, struct page* page)
{
nfs_readdir_descriptor_t *desc = data;
struct inode *inode = file_inode(desc->file);
int ret;
ret = nfs_readdir_xdr_to_array(desc, page, inode);
if (ret < 0)
goto error;
SetPageUptodate(page);
if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) {
/* Should never happen */
nfs_zap_mapping(inode, inode->i_mapping);
}
unlock_page(page);
return 0;
error:
nfs_readdir_clear_array(page);
unlock_page(page);
return ret;
}
static
void cache_page_release(nfs_readdir_descriptor_t *desc)
static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc)
{
put_page(desc->page);
desc->page = NULL;
}
static
struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
static void
nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc)
{
return read_cache_page(desc->file->f_mapping, desc->page_index,
nfs_readdir_filler, desc);
unlock_page(desc->page);
nfs_readdir_page_put(desc);
}
static struct page *
nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
{
return nfs_readdir_page_get_locked(desc->file->f_mapping,
desc->page_index,
desc->last_cookie);
}
/*
@ -785,23 +803,21 @@ int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc)
struct nfs_inode *nfsi = NFS_I(inode);
int res;
desc->page = get_cache_page(desc);
if (IS_ERR(desc->page))
return PTR_ERR(desc->page);
res = lock_page_killable(desc->page);
if (res != 0)
goto error;
res = -EAGAIN;
if (desc->page->mapping != NULL) {
res = nfs_readdir_search_array(desc);
if (res == 0) {
nfsi->page_index = desc->page_index;
return 0;
}
desc->page = nfs_readdir_page_get_cached(desc);
if (!desc->page)
return -ENOMEM;
if (nfs_readdir_page_needs_filling(desc->page)) {
res = nfs_readdir_xdr_to_array(desc, desc->page, inode);
if (res < 0)
goto error;
}
res = nfs_readdir_search_array(desc);
if (res == 0) {
nfsi->page_index = desc->page_index;
return 0;
}
unlock_page(desc->page);
error:
cache_page_release(desc);
nfs_readdir_page_unlock_and_put_cached(desc);
return res;
}
@ -896,6 +912,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
desc->page = page;
desc->duped = 0;
nfs_readdir_page_init_array(page, desc->dir_cookie);
status = nfs_readdir_xdr_to_array(desc, page, inode);
if (status < 0)
goto out_release;
@ -904,7 +921,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
out_release:
nfs_readdir_clear_array(desc->page);
cache_page_release(desc);
nfs_readdir_page_put(desc);
out:
dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
__func__, status);
@ -976,8 +993,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
break;
res = nfs_do_filldir(desc);
unlock_page(desc->page);
cache_page_release(desc);
nfs_readdir_page_unlock_and_put_cached(desc);
if (res < 0)
break;
} while (!desc->eof);