Am Donnerstag, 24. Juli 2014, 22:48:05 schrieben Sie:
> When failing to allocate space for the whole compressed extent, we'll
> fallback to uncompressed IO, but we've forgotten to redirty the pages
> which belong to this compressed extent, and these 'clean' pages will
> simply skip 'submit' part and go to endio directly, at last we got data
> corruption as we write nothing.
>
> Signed-off-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
> ---
> fs/btrfs/inode.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 3668048..8ea7610 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -709,6 +709,18 @@ retry:
> unlock_extent(io_tree, async_extent->start,
> async_extent->start +
> async_extent->ram_size - 1);
> +
> + /*
> + * we need to redirty the pages if we decide to
> + * fallback to uncompressed IO, otherwise we
> + * will not submit these pages down to lower
> + * layers.
> + */
> + extent_range_redirty_for_io(inode,
> + async_extent->start,
> + async_extent->start +
> + async_extent->ram_size - 1);
> +
> goto retry;
> }
> goto out_free;
I am testing this currently. So far no lockup. Lets see. Still has not filled
the the block device with trees completely after I balanced them:
Label: 'home' uuid: […]
Total devices 2 FS bytes used 125.57GiB
devid 1 size 160.00GiB used 153.00GiB path /dev/dm-0
devid 2 size 160.00GiB used 153.00GiB path /dev/mapper/sata-home
I believe the lockups happen more easily if the trees occupy all of disk
space. Well I will do some compiling of some KDE components which may let
BTRFS fill all space again.
This patch will mean it when it can´t make enough free space in the
(fragmented) tree it will write uncompressed?
This would mean that one would have a defragment trees regularily to allow for
writes to happen compressed at all times.
Well… of course still better than lockup or corruption.
Ciao,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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