On Wed, 2011-05-11 at 09:47 +0800, Yongqiang Yang wrote:
> On Wed, May 11, 2011 at 1:56 AM, Allison Henderson
> <achender@xxxxxxxxxxxxxxxxxx> wrote:
> > Hi All,
> >
> > We've been trying to get punch hole through some extended fsx tests, and I ran across some other tests that were failing because the test file contained zeros where it shouldn't. I made this fix to the ext4_ext_convert_to_initialized
>
> What do you mean zeros here?
> Some useful data is zeroed?
>
> and the test has been running smooth for about an hour now.
> Yongqiang, this one looks like it may have been associated with the
> split extents clean up patch. Would you mind taking a look at this
> fix and giving it your ok if it looks good? Thx!
> >
> > Signed-off-by: Allison Henderson <achender@xxxxxxxxxx>
> > ---
> > :100644 100644 e363f21... ce69450... M fs/ext4/extents.c
> > fs/ext4/extents.c | 3 ++-
> > 1 files changed, 2 insertions(+), 1 deletions(-)
> >
> > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> > index e363f21..ce69450 100644
> > --- a/fs/ext4/extents.c
> > +++ b/fs/ext4/extents.c
> > @@ -2819,7 +2819,8 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
> > /* case 3 */
> > zero_ex.ee_block =
> > cpu_to_le32(map->m_lblk + map->m_len);
> > - zero_ex.ee_len = cpu_to_le16(allocated - map->m_len);
> > + zero_ex.ee_len = cpu_to_le16(ee_len -
> > + allocated - map->m_len);
> The logic is that we splits [ee_block, ee_block + ee_len) into
> [ee_block, map->m_blk) that is uninitialized and [map->m_blk, ee_block
> + ee_len) that is initialized. We need to zero [map->m_lblk +
> map->m_len, ee_block + ee_len).
> and [map->m_lblk, map->m_lblk + map->m_len) is zeroed by upper layer
> because of MAP_NEW flag.
>
> Right logic?
>
Hmm, the logic in case 3 is-- if ex2[map->m_blk, map->m_blk+m_len] and
ex3 together[map->mblk+m_len+1, map->m_blk+allocated] total length
(allocated)is < than 7 blocks, then we zero out the entire ex2 and ext3,
there is no need to do split.
I think zero_ex.ee_len should be "allocated". Look at the original code
(before the extents splits cleanup patches), it will zero out entire
[map->mblk, map->m_blk+allocated] and don't do split anymore.
something like this, not a patch, but show what I think the right fix.
if (allocated > map->m_len) {
if (allocated <= EXT4_EXT_ZERO_LEN &&
(EXT4_EXT_MAY_ZEROOUT & split_flag)) {
/* case 3 */
zero_ex.ee_block =
cpu_to_le32(map->m_lblk + map->m_len);
- zero_ex.ee_len = cpu_to_le16(allocated - map->m_len);
zero_ex.ee_len = cpu_to_le16(allocated);
ext4_ext_store_pblock(&zero_ex,
ext4_ext_pblock(ex) + map->m_lblk - ee_block);
err = ext4_ext_zeroout(inode, &zero_ex);
if (err)
goto out;
- split_map.m_lblk = map->m_lblk;
- split_map.m_len = allocated;
+ ext4_ext_mark_initialized(ex);
+ ext4_ext_try_to_merge(inode, path, ex);
+ err = ext4_ext_dirty(handle, inode, path + depth);
+ goto out;
}
Mingming
>
> I can not see the error and the meaning of ee_len - allocated - map->m_len.
>
> Thanks,
> Yongqiang.
>
>
> > ext4_ext_store_pblock(&zero_ex,
> > ext4_ext_pblock(ex) + map->m_lblk - ee_block);
> > err = ext4_ext_zeroout(inode, &zero_ex);
> > --
> > 1.7.1
> >
> >
>
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
