From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:57214 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727216AbeI0ULD (ORCPT ); Thu, 27 Sep 2018 16:11:03 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.22/8.16.0.22) with SMTP id w8RDoITt001538 for ; Thu, 27 Sep 2018 06:52:40 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by m0001303.ppops.net with ESMTP id 2mrya4g84m-1 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 27 Sep 2018 06:52:39 -0700 From: Dan Schatzberg To: Miklos Szeredi CC: , , Dan Schatzberg , , Subject: [PATCH] fuse: enable caching of symlinks Date: Thu, 27 Sep 2018 06:52:10 -0700 Message-ID: <20180927135211.31641-1-dschatzberg@fb.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-fsdevel-owner@vger.kernel.org List-ID: FUSE file reads are cached in the page cache, but symlink reads are not. This patch enables FUSE READLINK operations to be cached which can improve performance of some FUSE workloads. In particular, I'm working on a FUSE filesystem for access to source code and discovered that about a 10% improvement to build times is achieved with this patch (there are a lot of symlinks in the source tree). Please provide feedback, I'm looking to flesh this out more. Signed-off-by: Dan Schatzberg --- fs/fuse/dir.c | 70 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 43 insertions(+), 27 deletions(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 0979609d6eba..3c0a81ef5bca 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1398,38 +1398,46 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx) return err; } -static const char *fuse_get_link(struct dentry *dentry, - struct inode *inode, - struct delayed_call *done) +static int fuse_symlink_readpage(struct file *file, struct page *page) { + struct inode *inode = page->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); - FUSE_ARGS(args); - char *link; - ssize_t ret; - - if (!dentry) - return ERR_PTR(-ECHILD); + struct fuse_req *req; + int err; + size_t num_read; - link = kmalloc(PAGE_SIZE, GFP_KERNEL); - if (!link) - return ERR_PTR(-ENOMEM); + err = -EIO; + if (is_bad_inode(inode)) + goto out; - args.in.h.opcode = FUSE_READLINK; - args.in.h.nodeid = get_node_id(inode); - args.out.argvar = 1; - args.out.numargs = 1; - args.out.args[0].size = PAGE_SIZE - 1; - args.out.args[0].value = link; - ret = fuse_simple_request(fc, &args); - if (ret < 0) { - kfree(link); - link = ERR_PTR(ret); - } else { - link[ret] = '\0'; - set_delayed_call(done, kfree_link, link); + req = fuse_get_req(fc, 1); + if (IS_ERR(req)) { + err = PTR_ERR(req); + goto out; } + + req->out.page_zeroing = 1; + req->out.argpages = 1; + req->num_pages = 1; + req->pages[0] = page; + req->page_descs[0].length = PAGE_SIZE - 1; + req->in.h.opcode = FUSE_READLINK; + req->in.h.nodeid = get_node_id(inode); + req->out.argvar = 1; + req->out.numargs = 1; + req->out.args[0].size = PAGE_SIZE - 1; + fuse_request_send(fc, req); + num_read = req->out.args[0].size; + err = req->out.h.error; + + if (!err) + SetPageUptodate(page); + + fuse_put_request(fc, req); fuse_invalidate_atime(inode); - return link; +out: + unlock_page(page); + return err; } static int fuse_dir_open(struct inode *inode, struct file *file) @@ -1855,7 +1863,7 @@ static const struct inode_operations fuse_common_inode_operations = { static const struct inode_operations fuse_symlink_inode_operations = { .setattr = fuse_setattr, - .get_link = fuse_get_link, + .get_link = page_get_link, .getattr = fuse_getattr, .listxattr = fuse_listxattr, }; @@ -1871,7 +1879,15 @@ void fuse_init_dir(struct inode *inode) inode->i_fop = &fuse_dir_operations; } +static const struct address_space_operations fuse_symlink_aops = { + .readpage = fuse_symlink_readpage, +}; + void fuse_init_symlink(struct inode *inode) { inode->i_op = &fuse_symlink_inode_operations; + inode->i_data.a_ops = &fuse_symlink_aops; + mapping_set_gfp_mask(inode->i_mapping, + mapping_gfp_constraint(inode->i_mapping, + ~(__GFP_FS | __GFP_HIGHMEM))); } -- 2.17.1