From 227823d2074da0c138d2abc0074b2dd281bbf923 Mon Sep 17 00:00:00 2001 From: Dai Ngo Date: Wed, 22 Jan 2020 20:45:39 -0500 Subject: [PATCH] nfs: optimise readdir cache page invalidation When the directory is large and it's being modified by one client while another client is doing the 'ls -l' on the same directory then the cache page invalidation from nfs_force_use_readdirplus causes the reading client to keep restarting READDIRPLUS from cookie 0 which causes the 'ls -l' to take a very long time to complete, possibly never completing. Currently when nfs_force_use_readdirplus is called to switch from READDIR to READDIRPLUS, it invalidates all the cached pages of the directory. This cache page invalidation causes the next nfs_readdir to re-read the directory content from cookie 0. This patch is to optimise the cache invalidation in nfs_force_use_readdirplus by only truncating the cached pages from last page index accessed to the end the file. It also marks the inode to delay invalidating all the cached page of the directory until the next initial nfs_readdir of the next 'ls' instance. Signed-off-by: Dai Ngo Reviewed-by: Trond Myklebust [Anna - Fix conflicts with Trond's readdir patches] [Anna - Remove redundant call to nfs_zap_mapping()] [Anna - Replace d_inode(file_dentry(desc->file)) with file_inode(desc->file)] Signed-off-by: Anna Schumaker --- fs/nfs/dir.c | 9 +++++++-- include/linux/nfs_fs.h | 3 +++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 88f6cf1ccf8c..1320288ff9ec 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -449,7 +449,8 @@ void nfs_force_use_readdirplus(struct inode *dir) if (nfs_server_capable(dir, NFS_CAP_READDIRPLUS) && !list_empty(&nfsi->open_files)) { set_bit(NFS_INO_ADVISE_RDPLUS, &nfsi->flags); - invalidate_mapping_pages(dir->i_mapping, 0, -1); + invalidate_mapping_pages(dir->i_mapping, + nfsi->page_index + 1, -1); } } @@ -720,6 +721,8 @@ struct page *get_cache_page(nfs_readdir_descriptor_t *desc) static int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc) { + struct inode *inode = file_inode(desc->file); + struct nfs_inode *nfsi = NFS_I(inode); int res; desc->page = get_cache_page(desc); @@ -731,8 +734,10 @@ int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc) res = -EAGAIN; if (desc->page->mapping != NULL) { res = nfs_readdir_search_array(desc); - if (res == 0) + if (res == 0) { + nfsi->page_index = desc->page_index; return 0; + } } unlock_page(desc->page); error: diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index c06b1fd130f3..a5f8f03ecd59 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -168,6 +168,9 @@ struct nfs_inode { struct rw_semaphore rmdir_sem; struct mutex commit_mutex; + /* track last access to cached pages */ + unsigned long page_index; + #if IS_ENABLED(CONFIG_NFS_V4) struct nfs4_cached_acl *nfs4_acl; /* NFSv4 state */ -- 2.30.2