GFS2: Wake up io waiters whenever a flush is done

Before this patch, if a process called function gfs2_log_reserve to
reserve some journal blocks, but the journal not enough blocks were
free, it would call io_schedule. However, in the log flush daemon,
it woke up the waiters only if an gfs2_ail_flush was no longer
required. This resulted in situations where processes would wait
forever because the number of blocks required was so high that it
pushed the journal into a perpetual state of flush being required.

This patch changes the logd daemon so that it wakes up io waiters
every time the log is actually flushed.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Bob Peterson 2017-01-06 22:14:28 -05:00
parent f07b352021
commit b63f5e8482

View File

@ -918,12 +918,15 @@ int gfs2_logd(void *data)
struct gfs2_sbd *sdp = data;
unsigned long t = 1;
DEFINE_WAIT(wait);
bool did_flush;
while (!kthread_should_stop()) {
did_flush = false;
if (gfs2_jrnl_flush_reqd(sdp) || t == 0) {
gfs2_ail1_empty(sdp);
gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
did_flush = true;
}
if (gfs2_ail_flush_reqd(sdp)) {
@ -931,9 +934,10 @@ int gfs2_logd(void *data)
gfs2_ail1_wait(sdp);
gfs2_ail1_empty(sdp);
gfs2_log_flush(sdp, NULL, NORMAL_FLUSH);
did_flush = true;
}
if (!gfs2_ail_flush_reqd(sdp))
if (!gfs2_ail_flush_reqd(sdp) || did_flush)
wake_up(&sdp->sd_log_waitq);
t = gfs2_tune_get(sdp, gt_logd_secs) * HZ;