From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wg0-f43.google.com ([74.125.82.43]:62363 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030195AbaEaAbN (ORCPT ); Fri, 30 May 2014 20:31:13 -0400 Received: by mail-wg0-f43.google.com with SMTP id l18so2677575wgh.2 for ; Fri, 30 May 2014 17:31:12 -0700 (PDT) From: Filipe David Borba Manana To: linux-btrfs@vger.kernel.org Cc: Filipe David Borba Manana Subject: [PATCH v3] Btrfs: avoid visiting all extent items when cloning a range Date: Sat, 31 May 2014 02:31:05 +0100 Message-Id: <1401499865-11669-1-git-send-email-fdmanana@gmail.com> In-Reply-To: <1401469001-26866-1-git-send-email-fdmanana@gmail.com> References: <1401469001-26866-1-git-send-email-fdmanana@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: When cloning a range of a file, we were visiting all the extent items in the btree that belong to our source inode. We don't need to visit those extent items that don't overlap the range we are cloning, as doing so only makes us waste time and do unnecessary btree navigations (btrfs_next_leaf) for inodes that have a large number of file extent items in the btree. Signed-off-by: Filipe David Borba Manana --- V2: Leave the loop as soon as we process the last extent, to avoid one extra and unnecessary btree search. V3: Removed unintentional and unrelated change from v2. fs/btrfs/ioctl.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 603c036..04ece8f 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3025,7 +3025,7 @@ static int btrfs_clone(struct inode *src, struct inode *inode, /* clone data */ key.objectid = btrfs_ino(src); key.type = BTRFS_EXTENT_DATA_KEY; - key.offset = 0; + key.offset = off; while (1) { /* @@ -3037,6 +3037,17 @@ static int btrfs_clone(struct inode *src, struct inode *inode, 0, 0); if (ret < 0) goto out; + /* + * First search, if no extent item that starts at offset off was + * found but the previous item is an extent item, it's possible + * it might overlap our target range, therefore process it. + */ + if (key.offset == off && ret > 0 && path->slots[0] > 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0] - 1); + if (key.type == BTRFS_EXTENT_DATA_KEY) + path->slots[0]--; + } nritems = btrfs_header_nritems(path->nodes[0]); process_slot: @@ -3086,10 +3097,16 @@ process_slot: extent); } - if (key.offset + datal <= off || - key.offset >= off + len - 1) { + /* + * The first search might have left us at an extent + * item that ends before our target range's start, can + * happen if we have holes and NO_HOLES feature enabled. + */ + if (key.offset + datal <= off) { path->slots[0]++; goto process_slot; + } else if (key.offset >= off + len) { + break; } size = btrfs_item_size_nr(leaf, slot); @@ -3296,6 +3313,8 @@ process_slot: goto out; } ret = btrfs_end_transaction(trans, root); + if (new_key.offset + datal >= destoff + len) + break; } btrfs_release_path(path); key.offset++; @@ -3303,7 +3322,6 @@ process_slot: ret = 0; out: - btrfs_release_path(path); btrfs_free_path(path); vfree(buf); return ret; -- 1.9.1