On Tue, Nov 20, 2018 at 09:25:56AM +0200, Nikolay Borisov wrote:
> From: Qu Wenruo <wqu@xxxxxxxx>
>
> [BUG]
> fstrim on some btrfs only trims the unallocated space, not trimming any
> space in existing block groups.
>
> [CAUSE]
> Before fstrim_range passed to btrfs_trim_fs(), it gets truncated to
> range [0, super->total_bytes). So later btrfs_trim_fs() will only be
> able to trim block groups in range [0, super->total_bytes).
>
> While for btrfs, any bytenr aligned to sectorsize is valid, since btrfs
> uses its logical address space, there is nothing limiting the location
> where we put block groups.
>
> For filesystem with frequent balance, it's quite easy to relocate all
> block groups and bytenr of block groups will start beyond
> super->total_bytes.
>
> In that case, btrfs will not trim existing block groups.
>
> [FIX]
> Just remove the truncation in btrfs_ioctl_fitrim(), so btrfs_trim_fs()
> can get the unmodified range, which is normally set to [0, U64_MAX].
>
> Reported-by: Chris Murphy <lists@xxxxxxxxxxxxxxxxx>
> Fixes: f4c697e6406d ("btrfs: return EINVAL if start > total_bytes in fitrim ioctl")
> CC: <stable@xxxxxxxxxxxxxxx> # v4.4+
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>
> Reviewed-by: David Sterba <dsterba@xxxxxxxx>
> Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> ---
>
> Hello Greg,
>
> Please apply upstream commit 6ba9fc8e628becf0e3ec94083450d089b0dec5f5 to
> 4.4.y and 4.9.y. This backport should apply cleanly to both trees.
This is already in 4.9.141, so I only applied it to 4.4.y
thanks,
greg k-h
