From c622ca543bff8e73efacf4dafa0cc9851ecea511 Mon Sep 17 00:00:00 2001 From: Artur Paszkiewicz Date: Tue, 16 Aug 2016 14:26:08 +0200 Subject: [PATCH] md: don't print the same repeated messages about delayed sync operation This fixes a long-standing bug that caused a flood of messages like: "md: delaying data-check of md1 until md2 has finished (they share one or more physical units)" It can be reproduced like this: 1. Create at least 3 raid1 arrays on a pair of disks, each on different partitions. 2. Request a sync operation like 'check' or 'repair' on 2 arrays by writing to their md/sync_action attribute files. One operation should start and one should be delayed and a message like the above will be printed. 3. Issue a write to the third array. Each write will cause 2 copies of the message to be printed. This happens when wake_up(&resync_wait) is called, usually by md_check_recovery(). Then the delayed sync thread again prints the message and is put to sleep. This patch adds a check in md_do_sync() to prevent printing this message more than once for the same pair of devices. Reported-by: Sven Koehler Link: https://bugzilla.kernel.org/show_bug.cgi?id=151801 Signed-off-by: Artur Paszkiewicz Signed-off-by: Shaohua Li --- drivers/md/md.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 19d8e23bda5c..cc25cbcf10b2 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -7865,6 +7865,7 @@ void md_do_sync(struct md_thread *thread) */ do { + int mddev2_minor = -1; mddev->curr_resync = 2; try_again: @@ -7894,10 +7895,14 @@ void md_do_sync(struct md_thread *thread) prepare_to_wait(&resync_wait, &wq, TASK_INTERRUPTIBLE); if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) && mddev2->curr_resync >= mddev->curr_resync) { - printk(KERN_INFO "md: delaying %s of %s" - " until %s has finished (they" - " share one or more physical units)\n", - desc, mdname(mddev), mdname(mddev2)); + if (mddev2_minor != mddev2->md_minor) { + mddev2_minor = mddev2->md_minor; + printk(KERN_INFO "md: delaying %s of %s" + " until %s has finished (they" + " share one or more physical units)\n", + desc, mdname(mddev), + mdname(mddev2)); + } mddev_put(mddev2); if (signal_pending(current)) flush_signals(current);