RE: [PATCH 5/5] ext4: Fix extent merging in ext4_ext_shift_path_extents()

[Namjae Jeon <namjae.jeon@samsung.com>]

> There is a bug in ext4_ext_shift_path_extents() where if we actually
> manage to merge a extent we would skip shifting the next extent. This
> will result in in one extent in the extent tree not being properly
> shifted.
> 
> This is causing failure in various xfstests tests using fsx or fsstress
> with collapse range support. It will also cause file system corruption
> which looks something like:
> 
>  e2fsck 1.42.9 (4-Feb-2014)
>  Pass 1: Checking inodes, blocks, and sizes
>  Inode 20 has out of order extents
>         (invalid logical block 3, physical block 492938, len 2)
>  Clear? yes
>  ...
> 
> when running e2fsck.
> 
> It's also very easily reproducible just by running fsx without any
> parameters. I can usually hit the problem within a minute.
> 
> Fix it by increasing ex_start only if we're not merging the extent.
> 
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
You can add : Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>

Thanks!