From patchwork Mon Jan 27 13:28:31 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gerhard Heift X-Patchwork-Id: 3542241 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 135A4C02DC for ; Mon, 27 Jan 2014 13:29:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 987A820131 for ; Mon, 27 Jan 2014 13:29:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C2CF420121 for ; Mon, 27 Jan 2014 13:29:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753866AbaA0N3J (ORCPT ); Mon, 27 Jan 2014 08:29:09 -0500 Received: from mail-ee0-f52.google.com ([74.125.83.52]:53286 "EHLO mail-ee0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753745AbaA0N3H (ORCPT ); Mon, 27 Jan 2014 08:29:07 -0500 Received: by mail-ee0-f52.google.com with SMTP id e53so2256908eek.11 for ; Mon, 27 Jan 2014 05:29:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=rRkGDhpGFjvK5azrEE6n4HQFpsAKXfkRYQgqI+ZXm7c=; b=IxRejQ/tEUWJ/6OCmA6CkjDv8YHxR+mOf7xo6PQHqwKf/PFibSupH5DSO7CktwTnA3 roF5QDsMi5kHHkSK4XJLZFc4AkDCMfAp+TVbu3XvJ/5ovBkO5miB7OQVnVbZW84sn/NV Rxks91MPc4I9e40JAG8Wo2VO/B46CWPYeOZLyipZRmdMhpezowpoaR4ImrXD0DLxlXyp apbb4NRzPmx3be5688+71SK3dR/fGqJQ/JY/AnPO0Hscdmy9LMIjl91T3BVKarS7v1KW LG5uk8C09niWPfkv/5inMqHsy2Bt4aEy0R2wn3JxJRzCzE0Jv8k/BL588YaWDmEZDeYh i91g== X-Gm-Message-State: ALoCoQnVgS/3mpkVgCRgR36ti6xZEMWuHMfyVEOC8Hgue3laq7n4q7stQKckcx5MS6hQcqbe9TsJ X-Received: by 10.14.177.200 with SMTP id d48mr25043972eem.8.1390829346654; Mon, 27 Jan 2014 05:29:06 -0800 (PST) Received: from localhost (host-115-115.kawo1.rwth-aachen.de. [134.130.115.115]) by mx.google.com with ESMTPSA id o43sm42500302eef.12.2014.01.27.05.29.05 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Mon, 27 Jan 2014 05:29:05 -0800 (PST) From: Gerhard Heift To: linux-btrfs@vger.kernel.org Subject: [PATCH RFCv2 5/6] btrfs: search_ioctl: direct copy to userspace Date: Mon, 27 Jan 2014 14:28:31 +0100 Message-Id: <1390829312-814-6-git-send-email-Gerhard@Heift.Name> X-Mailer: git-send-email 1.8.5.3 In-Reply-To: <1390829312-814-1-git-send-email-Gerhard@Heift.Name> References: <1390829312-814-1-git-send-email-Gerhard@Heift.Name> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-7.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP By copying each found item seperatly to userspace, we only need a small buffer in the kernel. This allows to run a large search inside of a single call. Signed-off-by: Gerhard Heift --- fs/btrfs/ioctl.c | 107 ++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 71 insertions(+), 36 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index c44fcdd..38403e6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1851,7 +1851,7 @@ static noinline int copy_to_sk(struct btrfs_root *root, struct btrfs_key *key, struct btrfs_ioctl_search_key *sk, size_t buf_size, - char *buf, + char __user *buf, unsigned long *sk_offset, int *num_found) { @@ -1865,6 +1865,9 @@ static noinline int copy_to_sk(struct btrfs_root *root, int slot; int ret = 0; + char *content_buffer = NULL; + unsigned long content_buffer_size = 0; + leaf = path->nodes[0]; slot = path->slots[0]; nritems = btrfs_header_nritems(leaf); @@ -1886,7 +1889,7 @@ static noinline int copy_to_sk(struct btrfs_root *root, if (sizeof(sh) + item_len > buf_size) { if (*num_found) { ret = 1; - goto overflow; + goto err; } item_len = 0; @@ -1895,7 +1898,7 @@ static noinline int copy_to_sk(struct btrfs_root *root, if (sizeof(sh) + item_len + *sk_offset > buf_size) { ret = 1; - goto overflow; + goto err; } sh.objectid = key->objectid; @@ -1905,20 +1908,47 @@ static noinline int copy_to_sk(struct btrfs_root *root, sh.transid = found_transid; /* copy search result header */ - memcpy(buf + *sk_offset, &sh, sizeof(sh)); + if (copy_to_user(buf + *sk_offset, &sh, sizeof(sh))) { + ret = -EFAULT; + goto err; + } + *sk_offset += sizeof(sh); if (item_len) { - char *p = buf + *sk_offset; + /* resize internal buffer if needed */ + if (content_buffer_size < item_len) { + kfree(content_buffer); + + content_buffer_size = + ALIGN(item_len, PAGE_SIZE); + + content_buffer = kmalloc_track_caller( + content_buffer_size, GFP_KERNEL); + + if (!content_buffer) { + content_buffer_size = 0; + ret = -ENOMEM; + goto err; + } + } + /* copy the item */ - read_extent_buffer(leaf, p, + read_extent_buffer(leaf, content_buffer, item_off, item_len); + + if (copy_to_user(buf + *sk_offset, + content_buffer, item_len)) { + ret = -EFAULT; + goto err; + } + *sk_offset += item_len; } (*num_found)++; if (ret) /* -EOVERFLOW from above */ - goto overflow; + goto err; if (*num_found >= sk->nr_items) break; @@ -1936,14 +1966,25 @@ advance_key: key->objectid++; } else ret = 1; -overflow: +err: + /* + 0: all items from this leaf copied, continue with next + 1: more items can be copied, but buffer is too small or all items + were found. Either way, it will stops the loop which iterates to + the next leaf + -EOVERFLOW: item was to large for buffer + -ENOMEM: could not allocate memory for a temporary extent buffer + -EFAULT: could not copy extent buffer back to userspace + */ + kfree(content_buffer); + return ret; } static noinline int search_ioctl(struct inode *inode, struct btrfs_ioctl_search_key *sk, size_t buf_size, - char *buf + char __user *buf ) { struct btrfs_root *root; @@ -1996,6 +2037,7 @@ static noinline int search_ioctl(struct inode *inode, ret = copy_to_sk(root, path, &key, sk, buf_size, buf, &sk_offset, &num_found); btrfs_release_path(path); + if (ret || num_found >= sk->nr_items) break; @@ -2011,34 +2053,39 @@ err: static noinline int btrfs_ioctl_tree_search(struct file *file, void __user *argp) { - struct btrfs_ioctl_search_args *args; - struct inode *inode; - int ret; + struct btrfs_ioctl_search_args __user *usarg; + struct btrfs_ioctl_search_key *sk; + struct inode *inode; + int ret; if (!capable(CAP_SYS_ADMIN)) return -EPERM; - args = memdup_user(argp, sizeof(*args)); - if (IS_ERR(args)) - return PTR_ERR(args); + usarg = (struct btrfs_ioctl_search_args __user *)argp; + + sk = memdup_user(&usarg->key, sizeof(*sk)); + if (IS_ERR(sk)) + return PTR_ERR(sk); inode = file_inode(file); - ret = search_ioctl(inode, &args->key, sizeof(args->buf), args->buf); + ret = search_ioctl(inode, sk, sizeof(usarg->buf), usarg->buf); + /* the origin ioctl does handle too large results by returning an item + * with a len of 0 */ if (ret == -EOVERFLOW) ret = 0; - if (ret == 0 && copy_to_user(argp, args, sizeof(*args))) + if (ret == 0 && copy_to_user(argp, sk, sizeof(*sk))) ret = -EFAULT; - kfree(args); + kfree(sk); return ret; } static noinline int btrfs_ioctl_tree_search_v2(struct file *file, void __user *argp) { + struct btrfs_ioctl_search_args_v2 __user *usarg; struct btrfs_ioctl_search_args_v2 *args; struct inode *inode; int ret; - char *buf; size_t buf_size; if (!capable(CAP_SYS_ADMIN)) @@ -2049,31 +2096,19 @@ static noinline int btrfs_ioctl_tree_search_v2(struct file *file, if (IS_ERR(args)) return PTR_ERR(args); + usarg = (struct btrfs_ioctl_search_args_v2 __user *)argp; + buf_size = args->buf_size; if (buf_size < sizeof(struct btrfs_ioctl_search_header)) { kfree(args); - return -ENOMEM; - } - - /* limit memory */ - if (buf_size > PAGE_SIZE * 32) - buf_size = PAGE_SIZE * 32; - - buf = memdup_user(argp->buf, buf_size); - if (IS_ERR(buf)) { - kfree(args); - return PTR_ERR(buf); + return -EOVERFLOW; } inode = file_inode(file); - ret = search_ioctl(inode, &args->key, buf_size, buf); - if (ret == 0 && ( - copy_to_user(argp, args, sizeof(*args)) || - copy_to_user(argp->buf, buf, buf_size) - )) + ret = search_ioctl(inode, &args->key, buf_size, usarg->buf); + if (ret == 0 && copy_to_user(argp, args, sizeof(*args))) ret = -EFAULT; - kfree(buf); kfree(args); return ret; }