From 1f1d4aa4e4bcb4721d3c51f4c07dda790b6accd9 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 1 Nov 2020 12:34:43 -0500 Subject: [PATCH] NFS: Clean up directory array handling Refactor to use pagecache_get_page() so that we can fill the page in multiple stages. Signed-off-by: Trond Myklebust Reviewed-by: Benjamin Coddington Tested-by: Benjamin Coddington Tested-by: Dave Wysochanski --- fs/nfs/dir.c | 138 +++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 77 insertions(+), 61 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 68acbde..842f691 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -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) +static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc) { - 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; + put_page(desc->page); + desc->page = NULL; } -static -void cache_page_release(nfs_readdir_descriptor_t *desc) +static void +nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc) { - put_page(desc->page); - desc->page = NULL; + unlock_page(desc->page); + nfs_readdir_page_put(desc); } -static -struct page *get_cache_page(nfs_readdir_descriptor_t *desc) +static struct page * +nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc) { - return read_cache_page(desc->file->f_mapping, desc->page_index, - nfs_readdir_filler, 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); -- 2.7.4