From: Liu Bo Date: Wed, 2 Jul 2014 08:58:01 +0000 (+0800) Subject: Btrfs: fix race of using total_bytes_pinned X-Git-Tag: omap-for-v3.16/fixes-rc4~19^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d288db5dc0110c8e0732d099aaf7a05e2ea0e0c8;p=pandora-kernel.git Btrfs: fix race of using total_bytes_pinned This percpu counter @total_bytes_pinned is introduced to skip unnecessary operations of 'commit transaction', it accounts for those space we may free but are stuck in delayed refs. And we zero out @space_info->total_bytes_pinned every transaction period so we have a better idea of how much space we'll actually free up by committing this transaction. However, we do the 'zero out' part a little earlier, before we actually unpin space, so we end up returning ENOSPC when we actually have free space that's just unpinned from committing transaction. xfstests/generic/074 complained then. This fixes it by actually accounting the percpu pinned number when 'unpin', and since it's protected by space_info->lock, the race is gone now. Signed-off-by: Liu Bo Reviewed-by: Miao Xie Signed-off-by: Chris Mason --- Reading git-diff-tree failed