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 <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
parent
972bcdf233
commit
1f1d4aa4e4
1 changed files with 78 additions and 62 deletions
140
fs/nfs/dir.c
140
fs/nfs/dir.c
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@ -149,7 +149,7 @@ typedef struct nfs_readdir_descriptor {
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struct file *file;
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struct page *page;
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struct dir_context *ctx;
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unsigned long page_index;
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pgoff_t page_index;
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u64 dir_cookie;
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u64 last_cookie;
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u64 dup_cookie;
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@ -166,13 +166,18 @@ typedef struct nfs_readdir_descriptor {
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bool eof;
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} nfs_readdir_descriptor_t;
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static
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void nfs_readdir_init_array(struct page *page)
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static void nfs_readdir_array_init(struct nfs_cache_array *array)
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{
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memset(array, 0, sizeof(struct nfs_cache_array));
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}
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static void nfs_readdir_page_init_array(struct page *page, u64 last_cookie)
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{
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struct nfs_cache_array *array;
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array = kmap_atomic(page);
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memset(array, 0, sizeof(struct nfs_cache_array));
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nfs_readdir_array_init(array);
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array->last_cookie = last_cookie;
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kunmap_atomic(array);
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}
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@ -188,7 +193,7 @@ void nfs_readdir_clear_array(struct page *page)
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array = kmap_atomic(page);
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for (i = 0; i < array->size; i++)
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kfree(array->array[i].string.name);
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array->size = 0;
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nfs_readdir_array_init(array);
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kunmap_atomic(array);
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}
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@ -268,6 +273,44 @@ out:
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return ret;
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}
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static struct page *nfs_readdir_page_get_locked(struct address_space *mapping,
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pgoff_t index, u64 last_cookie)
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{
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struct page *page;
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page = grab_cache_page(mapping, index);
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if (page && !PageUptodate(page)) {
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nfs_readdir_page_init_array(page, last_cookie);
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if (invalidate_inode_pages2_range(mapping, index + 1, -1) < 0)
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nfs_zap_mapping(mapping->host, mapping);
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SetPageUptodate(page);
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}
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return page;
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}
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static u64 nfs_readdir_page_last_cookie(struct page *page)
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{
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struct nfs_cache_array *array;
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u64 ret;
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array = kmap_atomic(page);
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ret = array->last_cookie;
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kunmap_atomic(array);
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return ret;
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}
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static bool nfs_readdir_page_needs_filling(struct page *page)
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{
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struct nfs_cache_array *array;
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bool ret;
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array = kmap_atomic(page);
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ret = !nfs_readdir_array_is_full(array);
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kunmap_atomic(array);
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return ret;
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}
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static void nfs_readdir_page_set_eof(struct page *page)
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{
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struct nfs_cache_array *array;
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@ -682,10 +725,8 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
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int status = -ENOMEM;
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unsigned int array_size = ARRAY_SIZE(pages);
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nfs_readdir_init_array(page);
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entry.prev_cookie = 0;
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entry.cookie = desc->last_cookie;
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entry.cookie = nfs_readdir_page_last_cookie(page);
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entry.eof = 0;
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entry.fh = nfs_alloc_fhandle();
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entry.fattr = nfs_alloc_fattr();
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@ -730,48 +771,25 @@ out:
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return status;
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}
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/*
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* Now we cache directories properly, by converting xdr information
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* to an array that can be used for lookups later. This results in
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* fewer cache pages, since we can store more information on each page.
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* We only need to convert from xdr once so future lookups are much simpler
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*/
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static
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int nfs_readdir_filler(void *data, struct page* page)
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{
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nfs_readdir_descriptor_t *desc = data;
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struct inode *inode = file_inode(desc->file);
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int ret;
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ret = nfs_readdir_xdr_to_array(desc, page, inode);
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if (ret < 0)
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goto error;
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SetPageUptodate(page);
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if (invalidate_inode_pages2_range(inode->i_mapping, page->index + 1, -1) < 0) {
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/* Should never happen */
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nfs_zap_mapping(inode, inode->i_mapping);
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}
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unlock_page(page);
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return 0;
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error:
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nfs_readdir_clear_array(page);
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unlock_page(page);
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return ret;
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}
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static
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void cache_page_release(nfs_readdir_descriptor_t *desc)
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static void nfs_readdir_page_put(struct nfs_readdir_descriptor *desc)
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{
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put_page(desc->page);
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desc->page = NULL;
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}
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static
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struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
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static void
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nfs_readdir_page_unlock_and_put_cached(struct nfs_readdir_descriptor *desc)
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{
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return read_cache_page(desc->file->f_mapping, desc->page_index,
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nfs_readdir_filler, desc);
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unlock_page(desc->page);
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nfs_readdir_page_put(desc);
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}
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static struct page *
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nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
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{
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return nfs_readdir_page_get_locked(desc->file->f_mapping,
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desc->page_index,
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desc->last_cookie);
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}
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/*
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@ -785,23 +803,21 @@ int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc)
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struct nfs_inode *nfsi = NFS_I(inode);
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int res;
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desc->page = get_cache_page(desc);
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if (IS_ERR(desc->page))
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return PTR_ERR(desc->page);
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res = lock_page_killable(desc->page);
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if (res != 0)
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goto error;
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res = -EAGAIN;
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if (desc->page->mapping != NULL) {
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res = nfs_readdir_search_array(desc);
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if (res == 0) {
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nfsi->page_index = desc->page_index;
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return 0;
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}
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desc->page = nfs_readdir_page_get_cached(desc);
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if (!desc->page)
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return -ENOMEM;
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if (nfs_readdir_page_needs_filling(desc->page)) {
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res = nfs_readdir_xdr_to_array(desc, desc->page, inode);
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if (res < 0)
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goto error;
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}
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res = nfs_readdir_search_array(desc);
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if (res == 0) {
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nfsi->page_index = desc->page_index;
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return 0;
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}
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unlock_page(desc->page);
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error:
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cache_page_release(desc);
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nfs_readdir_page_unlock_and_put_cached(desc);
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return res;
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}
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@ -896,6 +912,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
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desc->page = page;
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desc->duped = 0;
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nfs_readdir_page_init_array(page, desc->dir_cookie);
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status = nfs_readdir_xdr_to_array(desc, page, inode);
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if (status < 0)
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goto out_release;
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@ -904,7 +921,7 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc)
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out_release:
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nfs_readdir_clear_array(desc->page);
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cache_page_release(desc);
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nfs_readdir_page_put(desc);
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out:
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dfprintk(DIRCACHE, "NFS: %s: returns %d\n",
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__func__, status);
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@ -976,8 +993,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
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break;
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res = nfs_do_filldir(desc);
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unlock_page(desc->page);
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cache_page_release(desc);
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nfs_readdir_page_unlock_and_put_cached(desc);
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if (res < 0)
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break;
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} while (!desc->eof);
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