Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754457Ab1DLIN4 (ORCPT ); Tue, 12 Apr 2011 04:13:56 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:61405 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752434Ab1DLINy (ORCPT ); Tue, 12 Apr 2011 04:13:54 -0400 Message-ID: <4DA409E6.7020406@cn.fujitsu.com> Date: Tue, 12 Apr 2011 16:14:30 +0800 From: Xiao Guangrong User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.15) Gecko/20110307 Fedora/3.1.9-0.39.b3pre.fc14 Thunderbird/3.1.9 MIME-Version: 1.0 To: Chris Mason CC: LKML , BTRFS Subject: [PATCH 1/2] Btrfs: allocate extent state and check the result properly X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-04-12 16:14:31, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-04-12 16:14:32, Serialize complete at 2011-04-12 16:14:32 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3465 Lines: 118 It doesn't allocate extent_state and check the result properly: - in set_extent_bit, it doesn't allocate extent_state if the path is not allowed wait - in clear_extent_bit, it doesn't check the result after atomic-ly allocate, we trigger BUG_ON() if it's fail - if allocate fail, we trigger BUG_ON instead of returning -ENOMEM since the return value of clear_extent_bit() is ignored by many callers Signed-off-by: Xiao Guangrong --- fs/btrfs/extent_io.c | 29 +++++++++++++++++++++-------- 1 files changed, 21 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 77c65a0..62d5bca 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -439,6 +439,16 @@ static int clear_state_bit(struct extent_io_tree *tree, return ret; } +static struct extent_state * +alloc_extent_state_atomic(struct extent_state *prealloc) +{ + if (!prealloc) + prealloc = alloc_extent_state(GFP_ATOMIC); + + BUG_ON(!prealloc); + return prealloc; +} + /* * clear some bits on a range in the tree. This may require splitting * or inserting elements in the tree, so the gfp mask is used to @@ -476,8 +486,7 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, again: if (!prealloc && (mask & __GFP_WAIT)) { prealloc = alloc_extent_state(mask); - if (!prealloc) - return -ENOMEM; + BUG_ON(!prealloc); } spin_lock(&tree->lock); @@ -529,8 +538,7 @@ hit_next: */ if (state->start < start) { - if (!prealloc) - prealloc = alloc_extent_state(GFP_ATOMIC); + prealloc = alloc_extent_state_atomic(prealloc); err = split_state(tree, state, prealloc, start); BUG_ON(err == -EEXIST); prealloc = NULL; @@ -551,8 +559,7 @@ hit_next: * on the first half */ if (state->start <= end && state->end > end) { - if (!prealloc) - prealloc = alloc_extent_state(GFP_ATOMIC); + prealloc = alloc_extent_state_atomic(prealloc); err = split_state(tree, state, prealloc, end + 1); BUG_ON(err == -EEXIST); if (wake) @@ -716,8 +723,7 @@ int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, again: if (!prealloc && (mask & __GFP_WAIT)) { prealloc = alloc_extent_state(mask); - if (!prealloc) - return -ENOMEM; + BUG_ON(!prealloc); } spin_lock(&tree->lock); @@ -734,6 +740,7 @@ again: */ node = tree_search(tree, start); if (!node) { + prealloc = alloc_extent_state_atomic(prealloc); err = insert_state(tree, prealloc, start, end, &bits); prealloc = NULL; BUG_ON(err == -EEXIST); @@ -802,6 +809,8 @@ hit_next: err = -EEXIST; goto out; } + + prealloc = alloc_extent_state_atomic(prealloc); err = split_state(tree, state, prealloc, start); BUG_ON(err == -EEXIST); prealloc = NULL; @@ -832,6 +841,8 @@ hit_next: this_end = end; else this_end = last_start - 1; + + prealloc = alloc_extent_state_atomic(prealloc); err = insert_state(tree, prealloc, start, this_end, &bits); BUG_ON(err == -EEXIST); @@ -856,6 +867,8 @@ hit_next: err = -EEXIST; goto out; } + + prealloc = alloc_extent_state_atomic(prealloc); err = split_state(tree, state, prealloc, end + 1); BUG_ON(err == -EEXIST); -- 1.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/