From: Eric Sandeen Subject: Re: [PATCH] ext4: Fix data corruption when writing to prealloc area Date: Fri, 18 Jul 2008 10:12:46 -0500 Message-ID: <4880B2EE.8030903@redhat.com> References: <1216387021-26384-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: cmm@us.ibm.com, tytso@mit.edu, linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from mx1.redhat.com ([66.187.233.31]:58942 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753040AbYGRPPn (ORCPT ); Fri, 18 Jul 2008 11:15:43 -0400 In-Reply-To: <1216387021-26384-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Aneesh Kumar K.V wrote: > We need to recalucate the path information on extent insert > even if depth doesn't change. Aneesh, do you have a compact test case for this? Thanks, -Eric > Signed-off-by: Aneesh Kumar K.V > --- > fs/ext4/extents.c | 41 +++++++++++++++++++++++------------------ > 1 files changed, 23 insertions(+), 18 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 7bdaeec..9c8541e 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2462,7 +2462,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > unsigned int newdepth; > /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */ > if (allocated <= EXT4_EXT_ZERO_LEN) { > - /* Mark first half uninitialized. > + /* > + * iblock == ee_block is handled by the zerouout > + * at the beginning. > + * Mark first half uninitialized. > * Mark second half initialized and zero out the > * initialized extent > */ > @@ -2485,7 +2488,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > ex->ee_len = orig_ex.ee_len; > ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); > ext4_ext_dirty(handle, inode, path + depth); > - /* zeroed the full extent */ > + /* blocks available from iblock */ > return allocated; > > } else if (err) > @@ -2513,6 +2516,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > err = PTR_ERR(path); > return err; > } > + /* get the second half extent details */ > ex = path[depth].p_ext; > err = ext4_ext_get_access(handle, inode, > path + depth); > @@ -2542,6 +2546,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); > ext4_ext_dirty(handle, inode, path + depth); > /* zeroed the full extent */ > + /* blocks available from iblock */ > return allocated; > > } else if (err) > @@ -2557,23 +2562,22 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > */ > orig_ex.ee_len = cpu_to_le16(ee_len - > ext4_ext_get_actual_len(ex3)); > - if (newdepth != depth) { > - depth = newdepth; > - ext4_ext_drop_refs(path); > - path = ext4_ext_find_extent(inode, iblock, path); > - if (IS_ERR(path)) { > - err = PTR_ERR(path); > - goto out; > - } > - eh = path[depth].p_hdr; > - ex = path[depth].p_ext; > - if (ex2 != &newex) > - ex2 = ex; > - > - err = ext4_ext_get_access(handle, inode, path + depth); > - if (err) > - goto out; > + depth = newdepth; > + ext4_ext_drop_refs(path); > + path = ext4_ext_find_extent(inode, iblock, path); > + if (IS_ERR(path)) { > + err = PTR_ERR(path); > + goto out; > } > + eh = path[depth].p_hdr; > + ex = path[depth].p_ext; > + if (ex2 != &newex) > + ex2 = ex; > + > + err = ext4_ext_get_access(handle, inode, path + depth); > + if (err) > + goto out; > + > allocated = max_blocks; > > /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying > @@ -2591,6 +2595,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle, > ext4_ext_store_pblock(ex, ext_pblock(&orig_ex)); > ext4_ext_dirty(handle, inode, path + depth); > /* zero out the first half */ > + /* blocks available from iblock */ > return allocated; > } > }