From: Filipe Manana <fdmanana@suse.com>
Date: Thu, 14 May 2015 19:41:07 +0000 (+0100)
Subject: Btrfs: wake up extent state waiters on unlock through clear_extent_bits
X-Git-Tag: omap-for-v4.2/fixes-rc1^2~69^2~44
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0f31871f4411b5c0d42fb4403dec83a21a96100b;p=pandora-kernel.git

Btrfs: wake up extent state waiters on unlock through clear_extent_bits

When we clear an extent state's EXTENT_LOCKED bit with clear_extent_bits()
through free_io_failure(), we weren't waking up any tasks waiting for the
extent's state EXTENT_LOCKED bit, leading to an hang.

So make sure clear_extent_bits() ends up waking up any waiters if the
bit EXTENT_LOCKED is supplied by its callers.

Zygo Blaxell was experiencing such hangs at inode eviction time after
file unlinks. Thanks to him for a set of scripts to reproduce the issue.

Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
---

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