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 <sven.koehler@gmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=151801
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 19d8e23..cc25cbc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7865,6 +7865,7 @@
*/
do {
+ int mddev2_minor = -1;
mddev->curr_resync = 2;
try_again:
@@ -7894,10 +7895,14 @@
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);