md/md: replace confusing resync progress 99.9% with new wording

while true; do cat /proc/mdstat | grep reshape; done

When any sync action is finishing or interrupted, the progress will show 99.9% before the sync thread is reaped. Many reporters has asked what happened to the last blocks. It might be a confusing meaning for users because the progress will be backward after the interrupted task is restarted.

Take a raid5 reshape for example:
mdadm -C --assume-clean /dev/md0 -l5 -n3 /dev/loop[012] echo 2000 > /proc/sys/dev/raid/speed_limit_max
echo 1000 > /proc/sys/dev/raid/speed_limit_min # slow down the speed mdadm /dev/md0 -a /dev/loop3
mdadm /dev/md0 --grow -n4
while true
do
    mdadm -S /dev/md0
    sleep 3
    mdadm -A /dev/md0 /dev/loop[0123]
done

And you can see the fake 99.9% progress by the following command:

Quoted 1 line

while true; do cat /proc/mdstat | grep reshape; done

Quoted 1 line

This confusing state can be fixed by exposing the real state to users. And I also correct the sync action type for display.

Reported-by Edwin Lin <[email protected]>

Reviewed-by Allen Peng <[email protected]>

Signed-off-by BingJing Chang <[email protected]>

---
 drivers/md/md.c | 25 +++++++++++++++----------

 1 file changed, 15 insertions(+), 10 deletions(-)

drivers/md/md.c +8 -0

index 4e4dee0..74106c7 100644
@@ -7593,6 +7593,14 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
      sector_t rt;
      int scale;
      unsigned int per_milli;
+    char *sync_action;
+
+    sync_action = (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ?
+        "reshape" :
+        (test_bit(MD_RECOVERY_CHECK, &mddev->recovery) ?
+        "check" :
+        (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
+        "resync" : "recovery")));
 

     if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) || test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))

drivers/md/md.c +4 -2

@@ -7602,9 +7610,11 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
 
      resync = mddev->curr_resync;
      if (resync <= 3) {
-        if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
+        if (test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
              /* Still cleaning up */
-            resync = max_sectors;
+            seq_printf(seq, "\t%s=CLEANING UP", sync_action);
+            return 1;
+        }
      } else if (resync > max_sectors)
          resync = max_sectors;

     else

drivers/md/md.c +3 -8

@@ -7612,13 +7622,13 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
 
      if (resync == 0) {
          if (mddev->recovery_cp < MaxSector) {
-            seq_printf(seq, "\tresync=PENDING");
+            seq_printf(seq, "\t%s=PENDING", sync_action);
              return 1;
          }
          return 0;
      }
      if (resync < 3) {
-        seq_printf(seq, "\tresync=DELAYED");
+        seq_printf(seq, "\t%s=DELAYED", sync_action);
          return 1;
      }

@@ -7648,12 +7658,7 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
          seq_printf(seq, "] ");
      }
      seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
-           (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
-            "reshape" :
-            (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
-             "check" :
-             (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
-              "resync" : "recovery"))),
+           sync_action,
             per_milli/10, per_milli % 10,
             (unsigned long long) resync/2,

            (unsigned long long) max_sectors/2);

Quoted 20 lines

When any sync action is finishing or interrupted, the progress will show 99.9% before the sync thread is reaped. Many reporters has asked what happened to the last blocks. It might be a confusing meaning for users because the progress will be backward after the interrupted task is restarted.

Take a raid5 reshape for example:
mdadm -C --assume-clean /dev/md0 -l5 -n3 /dev/loop[012] echo 2000 > /proc/sys/dev/raid/speed_limit_max
echo 1000 > /proc/sys/dev/raid/speed_limit_min # slow down the speed mdadm /dev/md0 -a /dev/loop3
mdadm /dev/md0 --grow -n4
while true
do
    mdadm -S /dev/md0
    sleep 3
    mdadm -A /dev/md0 /dev/loop[0123]
done

Quoted 2 lines

And you can see the fake 99.9% progress by the following command:

Quoted 1 line

while true; do cat /proc/mdstat | grep reshape; done

Seems it happened when the reshaping is interrupted by issue stop array cmd, if so, why not just check MD_RECOVERY_INTR in status_resync()?

Thanks,
Guoqing

Quoted 78 lines

Quoted 1 line

This confusing state can be fixed by exposing the real state to users. And I also correct the sync action type for display.

Reported-by Edwin Lin <[email protected]>

Reviewed-by Allen Peng <[email protected]>

Signed-off-by BingJing Chang <[email protected]>

---
 drivers/md/md.c | 25 +++++++++++++++----------

 1 file changed, 15 insertions(+), 10 deletions(-)

drivers/md/md.c +8 -0

index 4e4dee0..74106c7 100644
@@ -7593,6 +7593,14 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
      sector_t rt;
      int scale;
      unsigned int per_milli;
+    char *sync_action;
+
+    sync_action = (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) ?
+        "reshape" :
+        (test_bit(MD_RECOVERY_CHECK, &mddev->recovery) ?
+        "check" :
+        (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
+        "resync" : "recovery")));
 

     if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) || test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))

drivers/md/md.c +4 -2

@@ -7602,9 +7610,11 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
 
      resync = mddev->curr_resync;
      if (resync <= 3) {
-        if (test_bit(MD_RECOVERY_DONE, &mddev->recovery))
+        if (test_bit(MD_RECOVERY_DONE, &mddev->recovery)) {
              /* Still cleaning up */
-            resync = max_sectors;
+            seq_printf(seq, "\t%s=CLEANING UP", sync_action);
+            return 1;
+        }
      } else if (resync > max_sectors)
          resync = max_sectors;

     else

drivers/md/md.c +3 -8

@@ -7612,13 +7622,13 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
 
      if (resync == 0) {
          if (mddev->recovery_cp < MaxSector) {
-            seq_printf(seq, "\tresync=PENDING");
+            seq_printf(seq, "\t%s=PENDING", sync_action);
              return 1;
          }
          return 0;
      }
      if (resync < 3) {
-        seq_printf(seq, "\tresync=DELAYED");
+        seq_printf(seq, "\t%s=DELAYED", sync_action);
          return 1;
      }

@@ -7648,12 +7658,7 @@ static int status_resync(struct seq_file *seq, 
 struct mddev *mddev)
          seq_printf(seq, "] ");
      }
      seq_printf(seq, " %s =%3u.%u%% (%llu/%llu)",
-           (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)?
-            "reshape" :
-            (test_bit(MD_RECOVERY_CHECK, &mddev->recovery)?
-             "check" :
-             (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ?
-              "resync" : "recovery"))),
+           sync_action,
             per_milli/10, per_milli % 10,
             (unsigned long long) resync/2,

Quoted 1 line

            (unsigned long long) max_sectors/2);

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