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NFS: Clean up readdir struct nfs_cache_array

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Since the 'eof_index' is only ever used as a flag, make it so.
Also add a flag to detect if the page has been completely filled.

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 13:45:55 -05:00
parent 2e7a464179
commit b1e21c9743
1 changed files with 49 additions and 17 deletions
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66
fs/nfs/dir.c
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@ -138,9 +138,10 @@ struct nfs_cache_array_entry {
}; };
struct nfs_cache_array { struct nfs_cache_array {
int size;
int eof_index;
u64 last_cookie; u64 last_cookie;
unsigned int size;
unsigned char page_full : 1,
page_is_eof : 1;
struct nfs_cache_array_entry array[]; struct nfs_cache_array_entry array[];
}; };
@ -172,7 +173,6 @@ void nfs_readdir_init_array(struct page *page)
array = kmap_atomic(page); array = kmap_atomic(page);
memset(array, 0, sizeof(struct nfs_cache_array)); memset(array, 0, sizeof(struct nfs_cache_array));
array->eof_index = -1;
kunmap_atomic(array); kunmap_atomic(array);
} }
@ -192,6 +192,17 @@ void nfs_readdir_clear_array(struct page *page)
kunmap_atomic(array); kunmap_atomic(array);
} }
static void nfs_readdir_array_set_eof(struct nfs_cache_array *array)
{
array->page_is_eof = 1;
array->page_full = 1;
}
static bool nfs_readdir_array_is_full(struct nfs_cache_array *array)
{
return array->page_full;
}
/* /*
* the caller is responsible for freeing qstr.name * the caller is responsible for freeing qstr.name
* when called by nfs_readdir_add_to_array, the strings will be freed in * when called by nfs_readdir_add_to_array, the strings will be freed in
@ -213,6 +224,23 @@ int nfs_readdir_make_qstr(struct qstr *string, const char *name, unsigned int le
return 0; return 0;
} }
/*
* Check that the next array entry lies entirely within the page bounds
*/
static int nfs_readdir_array_can_expand(struct nfs_cache_array *array)
{
struct nfs_cache_array_entry *cache_entry;
if (array->page_full)
return -ENOSPC;
cache_entry = &array->array[array->size + 1];
if ((char *)cache_entry - (char *)array > PAGE_SIZE) {
array->page_full = 1;
return -ENOSPC;
}
return 0;
}
static static
int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page) int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
{ {
@ -220,13 +248,11 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
struct nfs_cache_array_entry *cache_entry; struct nfs_cache_array_entry *cache_entry;
int ret; int ret;
cache_entry = &array->array[array->size]; ret = nfs_readdir_array_can_expand(array);
if (ret)
/* Check that this entry lies within the page bounds */
ret = -ENOSPC;
if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE)
goto out; goto out;
cache_entry = &array->array[array->size];
cache_entry->cookie = entry->prev_cookie; cache_entry->cookie = entry->prev_cookie;
cache_entry->ino = entry->ino; cache_entry->ino = entry->ino;
cache_entry->d_type = entry->d_type; cache_entry->d_type = entry->d_type;
@ -236,12 +262,21 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
array->last_cookie = entry->cookie; array->last_cookie = entry->cookie;
array->size++; array->size++;
if (entry->eof != 0) if (entry->eof != 0)
array->eof_index = array->size; nfs_readdir_array_set_eof(array);
out: out:
kunmap(page); kunmap(page);
return ret; return ret;
} }
static void nfs_readdir_page_set_eof(struct page *page)
{
struct nfs_cache_array *array;
array = kmap_atomic(page);
nfs_readdir_array_set_eof(array);
kunmap_atomic(array);
}
static inline static inline
int is_32bit_api(void) int is_32bit_api(void)
{ {
@ -270,7 +305,7 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
if (diff < 0) if (diff < 0)
goto out_eof; goto out_eof;
if (diff >= array->size) { if (diff >= array->size) {
if (array->eof_index >= 0) if (array->page_is_eof)
goto out_eof; goto out_eof;
return -EAGAIN; return -EAGAIN;
} }
@ -334,7 +369,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
return 0; return 0;
} }
} }
if (array->eof_index >= 0) { if (array->page_is_eof) {
status = -EBADCOOKIE; status = -EBADCOOKIE;
if (desc->dir_cookie == array->last_cookie) if (desc->dir_cookie == array->last_cookie)
desc->eof = true; desc->eof = true;
@ -566,7 +601,6 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
struct xdr_stream stream; struct xdr_stream stream;
struct xdr_buf buf; struct xdr_buf buf;
struct page *scratch; struct page *scratch;
struct nfs_cache_array *array;
unsigned int count = 0; unsigned int count = 0;
int status; int status;
@ -604,10 +638,8 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
out_nopages: out_nopages:
if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) { if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
array = kmap(page); nfs_readdir_page_set_eof(page);
array->eof_index = array->size;
status = 0; status = 0;
kunmap(page);
} }
put_page(scratch); put_page(scratch);
@ -689,7 +721,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
status = 0; status = 0;
break; break;
} }
} while (array->eof_index < 0); } while (!nfs_readdir_array_is_full(array));
nfs_readdir_free_pages(pages, array_size); nfs_readdir_free_pages(pages, array_size);
out_release_array: out_release_array:
@ -825,7 +857,7 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
if (desc->duped != 0) if (desc->duped != 0)
desc->duped = 1; desc->duped = 1;
} }
if (array->eof_index >= 0) if (array->page_is_eof)
desc->eof = true; desc->eof = true;
kunmap(desc->page); kunmap(desc->page);