NFS: Clean up readdir struct nfs_cache_array

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>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 67d8595..604ebe0 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -138,9 +138,10 @@ struct nfs_cache_array_entry {
 };
 
 struct nfs_cache_array {
-       int size;
-       int eof_index;
        u64 last_cookie;
+       unsigned int size;
+       unsigned char page_full : 1,
+                     page_is_eof : 1;
        struct nfs_cache_array_entry array[];
 };
 
@@ -172,7 +173,6 @@ void nfs_readdir_init_array(struct page *page)
 
        array = kmap_atomic(page);
        memset(array, 0, sizeof(struct nfs_cache_array));
-       array->eof_index = -1;
        kunmap_atomic(array);
 }
 
@@ -192,6 +192,17 @@ void nfs_readdir_clear_array(struct page *page)
        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
  * 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;
 }
 
+/*
+ * 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
 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;
        int ret;
 
-       cache_entry = &array->array[array->size];
-
-       /* Check that this entry lies within the page bounds */
-       ret = -ENOSPC;
-       if ((char *)&cache_entry[1] - (char *)page_address(page) > PAGE_SIZE)
+       ret = nfs_readdir_array_can_expand(array);
+       if (ret)
                goto out;
 
+       cache_entry = &array->array[array->size];
        cache_entry->cookie = entry->prev_cookie;
        cache_entry->ino = entry->ino;
        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->size++;
        if (entry->eof != 0)
-               array->eof_index = array->size;
+               nfs_readdir_array_set_eof(array);
 out:
        kunmap(page);
        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
 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)
                goto out_eof;
        if (diff >= array->size) {
-               if (array->eof_index >= 0)
+               if (array->page_is_eof)
                        goto out_eof;
                return -EAGAIN;
        }
@@ -334,7 +369,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
                        return 0;
                }
        }
-       if (array->eof_index >= 0) {
+       if (array->page_is_eof) {
                status = -EBADCOOKIE;
                if (desc->dir_cookie == array->last_cookie)
                        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_buf buf;
        struct page *scratch;
-       struct nfs_cache_array *array;
        unsigned int count = 0;
        int status;
 
@@ -604,10 +638,8 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
 
 out_nopages:
        if (count == 0 || (status == -EBADCOOKIE && entry->eof != 0)) {
-               array = kmap(page);
-               array->eof_index = array->size;
+               nfs_readdir_page_set_eof(page);
                status = 0;
-               kunmap(page);
        }
 
        put_page(scratch);
@@ -689,7 +721,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
                                status = 0;
                        break;
                }
-       } while (array->eof_index < 0);
+       } while (!nfs_readdir_array_is_full(array));
 
        nfs_readdir_free_pages(pages, array_size);
 out_release_array:
@@ -825,7 +857,7 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc)
                if (desc->duped != 0)
                        desc->duped = 1;
        }
-       if (array->eof_index >= 0)
+       if (array->page_is_eof)
                desc->eof = true;
 
        kunmap(desc->page);