From patchwork Fri Jan 15 08:43:09 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Yan, Zheng" X-Patchwork-Id: 73111 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.2) with ESMTP id o0F8hoMP001329 for ; Fri, 15 Jan 2010 08:43:50 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755912Ab0AOInt (ORCPT ); Fri, 15 Jan 2010 03:43:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755832Ab0AOInt (ORCPT ); Fri, 15 Jan 2010 03:43:49 -0500 Received: from rcsinet11.oracle.com ([148.87.113.123]:27436 "EHLO rcsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751407Ab0AOIns (ORCPT ); Fri, 15 Jan 2010 03:43:48 -0500 Received: from acsinet15.oracle.com (acsinet15.oracle.com [141.146.126.227]) by rcsinet11.oracle.com (Switch-3.4.2/Switch-3.4.2) with ESMTP id o0F8hke8013714 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 15 Jan 2010 08:43:47 GMT Received: from acsmt354.oracle.com (acsmt354.oracle.com [141.146.40.154]) by acsinet15.oracle.com (Switch-3.4.2/Switch-3.4.1) with ESMTP id o0F8hikJ012351 for ; Fri, 15 Jan 2010 08:43:45 GMT Received: from abhmt009.oracle.com by acsmt355.oracle.com with ESMTP id 1336593301263544995; Fri, 15 Jan 2010 00:43:15 -0800 Received: from [10.182.121.20] (/10.182.121.20) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 15 Jan 2010 00:43:15 -0800 Message-ID: <4B502A9D.8090807@oracle.com> Date: Fri, 15 Jan 2010 16:43:09 +0800 From: "Yan, Zheng" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Thunderbird/3.0 MIME-Version: 1.0 To: chris Mason , linux-btrfs@vger.kernel.org Subject: [PATCH] btrfs: Fix race in btrfs_mark_extent_written X-Source-IP: acsmt354.oracle.com [141.146.40.154] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090207.4B502AC1.0166:SCFMA4539814,ss=1,fgs=0 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org diff -urp 1/fs/btrfs/file.c 2/fs/btrfs/file.c --- 1/fs/btrfs/file.c 2009-12-28 12:23:42.081546961 +0800 +++ 2/fs/btrfs/file.c 2010-01-11 13:02:08.082735125 +0800 @@ -506,7 +506,8 @@ next_slot: } static int extent_mergeable(struct extent_buffer *leaf, int slot, - u64 objectid, u64 bytenr, u64 *start, u64 *end) + u64 objectid, u64 bytenr, u64 orig_offset, + u64 *start, u64 *end) { struct btrfs_file_extent_item *fi; struct btrfs_key key; @@ -522,6 +523,7 @@ static int extent_mergeable(struct exten fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG || btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr || + btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset || btrfs_file_extent_compression(leaf, fi) || btrfs_file_extent_encryption(leaf, fi) || btrfs_file_extent_other_encoding(leaf, fi)) @@ -561,6 +563,7 @@ int btrfs_mark_extent_written(struct btr u64 split; int del_nr = 0; int del_slot = 0; + int recow; int ret; btrfs_drop_extent_cache(inode, start, end - 1, 0); @@ -568,6 +571,7 @@ int btrfs_mark_extent_written(struct btr path = btrfs_alloc_path(); BUG_ON(!path); again: + recow = 0; split = start; key.objectid = inode->i_ino; key.type = BTRFS_EXTENT_DATA_KEY; @@ -591,12 +595,60 @@ again: bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi); orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi); + memcpy(&new_key, &key, sizeof(new_key)); + + if (start == key.offset && end < extent_end) { + other_start = 0; + other_end = start; + if (extent_mergeable(leaf, path->slots[0] - 1, + inode->i_ino, bytenr, orig_offset, + &other_start, &other_end)) { + new_key.offset = end; + btrfs_set_item_key_safe(trans, root, path, &new_key); + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - end); + btrfs_set_file_extent_offset(leaf, fi, + end - orig_offset); + fi = btrfs_item_ptr(leaf, path->slots[0] - 1, + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + end - other_start); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } + + if (start > key.offset && end == extent_end) { + other_start = end; + other_end = 0; + if (extent_mergeable(leaf, path->slots[0] + 1, + inode->i_ino, bytenr, orig_offset, + &other_start, &other_end)) { + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + start - key.offset); + path->slots[0]++; + new_key.offset = start; + btrfs_set_item_key_safe(trans, root, path, &new_key); + + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + btrfs_set_file_extent_num_bytes(leaf, fi, + other_end - start); + btrfs_set_file_extent_offset(leaf, fi, + start - orig_offset); + btrfs_mark_buffer_dirty(leaf); + goto out; + } + } while (start > key.offset || end < extent_end) { if (key.offset == start) split = end; - memcpy(&new_key, &key, sizeof(new_key)); new_key.offset = split; ret = btrfs_duplicate_item(trans, root, path, &new_key); if (ret == -EAGAIN) { @@ -631,15 +683,18 @@ again: path->slots[0]--; extent_end = end; } + recow = 1; } - fi = btrfs_item_ptr(leaf, path->slots[0], - struct btrfs_file_extent_item); - other_start = end; other_end = 0; - if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino, - bytenr, &other_start, &other_end)) { + if (extent_mergeable(leaf, path->slots[0] + 1, + inode->i_ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(root, path); + goto again; + } extent_end = other_end; del_slot = path->slots[0] + 1; del_nr++; @@ -650,8 +705,13 @@ again: } other_start = 0; other_end = start; - if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino, - bytenr, &other_start, &other_end)) { + if (extent_mergeable(leaf, path->slots[0] - 1, + inode->i_ino, bytenr, orig_offset, + &other_start, &other_end)) { + if (recow) { + btrfs_release_path(root, path); + goto again; + } key.offset = other_start; del_slot = path->slots[0]; del_nr++; @@ -660,22 +720,22 @@ again: inode->i_ino, orig_offset); BUG_ON(ret); } + fi = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); if (del_nr == 0) { btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG); btrfs_mark_buffer_dirty(leaf); - goto out; - } - - fi = btrfs_item_ptr(leaf, del_slot - 1, - struct btrfs_file_extent_item); - btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG); - btrfs_set_file_extent_num_bytes(leaf, fi, - extent_end - key.offset); - btrfs_mark_buffer_dirty(leaf); + } else { + btrfs_set_file_extent_type(leaf, fi, + BTRFS_FILE_EXTENT_REG); + btrfs_set_file_extent_num_bytes(leaf, fi, + extent_end - key.offset); + btrfs_mark_buffer_dirty(leaf); - ret = btrfs_del_items(trans, root, path, del_slot, del_nr); - BUG_ON(ret); + ret = btrfs_del_items(trans, root, path, del_slot, del_nr); + BUG_ON(ret); + } out: btrfs_free_path(path); return 0;