From: Andreas Dilger Subject: Re: [PATCH] ext4: Protect group inode free counting with group lock. Date: Wed, 16 May 2012 08:58:23 -0600 Message-ID: <67D3F8EA-D06F-4691-A1E0-CA519CF581C5@dilger.ca> References: <1337158192-4591-1-git-send-email-tm@tao.ma> Mime-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, Theodore Ts'o To: Tao Ma Return-path: Received: from smtp-out-04.shaw.ca ([64.59.134.12]:28235 "EHLO smtp-out-04.shaw.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751858Ab2EPO6Y (ORCPT ); Wed, 16 May 2012 10:58:24 -0400 In-Reply-To: <1337158192-4591-1-git-send-email-tm@tao.ma> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2012-05-16, at 2:49 AM, Tao Ma wrote: > From: Tao Ma > > Now when we set the group inode free count, we don't have a proper > group lock so that multiple threads may decrease the inode free > count at the same time. And e2fsck will complain something like: > > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c > index 409c2ee..25595e2 100644 > --- a/fs/ext4/ialloc.c > +++ b/fs/ext4/ialloc.c > @@ -772,7 +772,9 @@ got: > ext4_itable_unused_set(sb, gdp, > (EXT4_INODES_PER_GROUP(sb) - ino)); > up_read(&grp->alloc_sem); > - } > + } else > + ext4_lock_group(sb, group); Minor coding style fix - when one half of if/else is using braces then the other half should also use braces, like: if { : } else { : } > + > ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1); > if (S_ISDIR(mode)) { > ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1); > @@ -782,10 +784,9 @@ got: > atomic_inc(&sbi->s_flex_groups[f].used_dirs); > } > } > - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { > + if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) > gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); > - ext4_unlock_group(sb, group); > - } > + ext4_unlock_group(sb, group); > > BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata"); > err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh); > -- > 1.7.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Cheers, Andreas