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NFS: Store the change attribute in the directory page cache

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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@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2022-02-22 08:31:28 -05:00
parent 0b2662b7e7
commit d09e673f49
1 changed files with 37 additions and 31 deletions
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68
fs/nfs/dir.c
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@ -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 @@ out:
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 @@ out_eof:
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);