From: Gang He <ghe@xxxxxxxx> Subject: ocfs2: fix potential soft lockup during fstrim When we discard unused blocks on a mounted ocfs2 filesystem, fstrim handles each block goup with locking/unlocking global bitmap meta-file repeatedly. we should let fstrim thread take a break(if need) between unlock and lock, this will avoid the potential soft lockup problem, and also gives the upper applications more IO opportunities, these applications are not blocked for too long at writing files. Link: https://lkml.kernel.org/r/20200927015815.14904-1-ghe@xxxxxxxx Signed-off-by: Gang He <ghe@xxxxxxxx> Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> Cc: Mark Fasheh <mark@xxxxxxxxxx> Cc: Joel Becker <jlbec@xxxxxxxxxxxx> Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx> Cc: Changwei Ge <gechangwei@xxxxxxx> Cc: Jun Piao <piaojun@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/ocfs2/alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/ocfs2/alloc.c~ocfs2-fix-potential-soft-lockup-during-fstrim +++ a/fs/ocfs2/alloc.c @@ -7654,8 +7654,10 @@ out_mutex: * main_bm related locks for avoiding the current IO starve, then go to * trim the next group */ - if (ret >= 0 && group <= last_group) + if (ret >= 0 && group <= last_group) { + cond_resched(); goto next_group; + } out: range->len = trimmed * sb->s_blocksize; return ret; _
