Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9bbd9bb4 authored by Peng Tao's avatar Peng Tao Committed by Trond Myklebust
Browse files

pnfs/flexfiles: protect ktime manipulation with mirror lock 



It looks as if xchg() and cmpxchg() are not available for 64-bit integers on sparc32:

> New breakage seen in linux-next today:
>
> ERROR: "__xchg_called_with_bad_pointer" [fs/nfs/flexfilelayout/nfs_layout_flexfiles.ko] undefined!
> ERROR: "__cmpxchg_called_with_bad_pointer" [fs/nfs/flexfilelayout/nfs_layout_flexfiles.ko] undefined!
> make[2]: *** [__modpost] Error 1
> make[1]: *** [modules] Error 2

Given that mirror ktime manipulation is already under mirror->lock, let's make use of the fact.

Reported-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarPeng Tao <tao.peng@primarydata.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 865a7ecb

fs/nfs/flexfilelayout/flexfilelayout.c

+12 −19
Original line number Diff line number Diff line
@@ -417,21 +417,9 @@ ff_layout_get_lseg_count(struct nfs4_ff_layout_segment *fls) 
static void

nfs4_ff_start_busy_timer(struct nfs4_ff_busy_timer *timer)

{

	ktime_t old, new;



	/*

	 * Note: careful here!

	 * If the counter is zero, then we must not increment it until after

	 * we've set the start_time.

	 * If we were instead to use atomic_inc_return(), then another

	 * request might come in, bump, and then call end_busy_timer()

	 * before we've set the timer->start_time.

	 */

	old = timer->start_time;

	if (atomic_inc_not_zero(&timer->n_ops) == 0) {

		new = ktime_get();

		cmpxchg(&timer->start_time.tv64, old.tv64, new.tv64);

		atomic_inc(&timer->n_ops);

	/* first IO request? */

	if (atomic_inc_return(&timer->n_ops) == 1) {

		timer->start_time = ktime_get();

	}

}
@@ -440,9 +428,12 @@ nfs4_ff_end_busy_timer(struct nfs4_ff_busy_timer *timer) 
{

	ktime_t start, now;



	if (atomic_dec_return(&timer->n_ops) < 0)

		WARN_ON_ONCE(1);



	now = ktime_get();

	start.tv64 = xchg(&timer->start_time.tv64, now.tv64);

	atomic_dec(&timer->n_ops);

	start = timer->start_time;

	timer->start_time = now;

	return ktime_sub(now, start);

}
@@ -460,8 +451,10 @@ nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror, 
	ktime_t now = ktime_get();



	nfs4_ff_start_busy_timer(&layoutstat->busy_timer);

	cmpxchg(&mirror->start_time.tv64, notime.tv64, now.tv64);

	cmpxchg(&mirror->last_report_time.tv64, notime.tv64, now.tv64);

	if (ktime_equal(mirror->start_time, notime))

		mirror->start_time = now;

	if (ktime_equal(mirror->last_report_time, notime))

		mirror->last_report_time = now;

	if (ktime_to_ms(ktime_sub(now, mirror->last_report_time)) >=

			FF_LAYOUTSTATS_REPORT_INTERVAL) {

		mirror->last_report_time = now;