From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Use the change attribute and the first cookie in a directory page cache
entry to validate that the page is up to date.
Suggested-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
---
fs/nfs/dir.c | 68 ++++++++++++++++++++++++++++------------------------
1 file changed, 37 insertions(+), 31 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 6f0a38db6c37..a1767f755460 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -140,6 +140,7 @@ struct nfs_cache_array_entry {
};
struct nfs_cache_array {
+ u64 change_attr;
u64 last_cookie;
unsigned int size;
unsigned char page_full : 1,
@@ -176,12 +177,14 @@ 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)
+static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie,
+ u64 change_attr)
{
struct nfs_cache_array *array;
array = kmap_atomic(page);
nfs_readdir_array_init(array);
+ array->change_attr = change_attr;
array->last_cookie = last_cookie;
array->cookies_are_ordered = 1;
kunmap_atomic(array);
@@ -208,7 +211,7 @@ nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags)
{
struct page *page = alloc_page(gfp_flags);
if (page)
- nfs_readdir_page_init_array(page, last_cookie);
+ nfs_readdir_page_init_array(page, last_cookie, 0);
return page;
}
@@ -305,19 +308,43 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
return ret;
}
+static bool nfs_readdir_page_validate(struct page *page, u64 last_cookie,
+ u64 change_attr)
+{
+ struct nfs_cache_array *array = kmap_atomic(page);
+ int ret = true;
+
+ if (array->change_attr != change_attr)
+ ret = false;
+ if (array->size > 0 && array->array[0].cookie != last_cookie)
+ ret = false;
+ kunmap_atomic(array);
+ return ret;
+}
+
+static void nfs_readdir_page_unlock_and_put(struct page *page)
+{
+ unlock_page(page);
+ put_page(page);
+}
+
static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
pgoff_t index, u64 last_cookie)
{
struct page *page;
+ u64 change_attr;
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);
+ if (!page)
+ return NULL;
+ change_attr = inode_peek_iversion_raw(mapping->host);
+ if (PageUptodate(page)) {
+ if (nfs_readdir_page_validate(page, last_cookie, change_attr))
+ return page;
+ nfs_readdir_clear_array(page);
}
-
+ nfs_readdir_page_init_array(page, last_cookie, change_attr);
+ SetPageUptodate(page);
return page;
}
@@ -357,12 +384,6 @@ static void nfs_readdir_page_set_eof(struct page *page)
kunmap_atomic(array);
}
-static void nfs_readdir_page_unlock_and_put(struct page *page)
-{
- unlock_page(page);
- put_page(page);
-}
-
static struct page *nfs_readdir_page_get_next(struct address_space *mapping,
pgoff_t index, u64 cookie)
{
@@ -419,16 +440,6 @@ static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,
return -EBADCOOKIE;
}
-static bool
-nfs_readdir_inode_mapping_valid(struct nfs_inode *nfsi)
-{
- if (nfsi->cache_validity & (NFS_INO_INVALID_CHANGE |
- NFS_INO_INVALID_DATA))
- return false;
- smp_rmb();
- return !test_bit(NFS_INO_INVALIDATING, &nfsi->flags);
-}
-
static bool nfs_readdir_array_cookie_in_range(struct nfs_cache_array *array,
u64 cookie)
{
@@ -457,8 +468,7 @@ static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));
new_pos = nfs_readdir_page_offset(desc->page) + i;
- if (desc->attr_gencount != nfsi->attr_gencount ||
- !nfs_readdir_inode_mapping_valid(nfsi)) {
+ if (desc->attr_gencount != nfsi->attr_gencount) {
desc->duped = 0;
desc->attr_gencount = nfsi->attr_gencount;
} else if (new_pos < desc->prev_index) {
@@ -1095,11 +1105,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
* to either find the entry with the appropriate number or
* revalidate the cookie.
*/
- if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) {
- res = nfs_revalidate_mapping(inode, file->f_mapping);
- if (res < 0)
- goto out;
- }
+ nfs_revalidate_mapping(inode, file->f_mapping);
res = -ENOMEM;
desc = kzalloc(sizeof(*desc), GFP_KERNEL);
--
2.35.1
