Stopping external metadata arrays during resync/recovery causes
retries, loop of interrupting and starting reconstruction, until it
hit at good moment to stop completely. While these retries
curr_mark_cnt can be small- especially on HDD drives, so subtraction
result can be smaller than 0. However it is casted to uint without
checking. As a result of it the status bar in /proc/mdstat while stopping
is strange (it jumps between 0% and 99%).
The real problem occurs here after commit 72deb455b5ec ("block: remove
CONFIG_LBDAF"). Sector_div() macro has been changed, now the
divisor is casted to uint32. For db = -8 the divisior(db/32-1) becomes 0.
Check if db value can be really counted and replace these macro by
div64_u64() inline.
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@xxxxxxxxx>
---
drivers/md/md.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 04f4f131f9d6..9a8b258ce1ef 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7607,9 +7607,9 @@ static void status_unused(struct seq_file *seq)
static int status_resync(struct seq_file *seq, struct mddev *mddev)
{
sector_t max_sectors, resync, res;
- unsigned long dt, db;
- sector_t rt;
- int scale;
+ unsigned long dt, db = 0;
+ sector_t rt, curr_mark_cnt, resync_mark_cnt;
+ int scale, recovery_active;
unsigned int per_milli;
if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
@@ -7709,11 +7709,16 @@ static int status_resync(struct seq_file *seq, struct mddev *mddev)
*/
dt = ((jiffies - mddev->resync_mark) / HZ);
if (!dt) dt++;
- db = (mddev->curr_mark_cnt - atomic_read(&mddev->recovery_active))
- - mddev->resync_mark_cnt;
+
+ curr_mark_cnt = mddev->curr_mark_cnt;
+ recovery_active = atomic_read(&mddev->recovery_active);
+ resync_mark_cnt = mddev->resync_mark_cnt;
+
+ if (curr_mark_cnt >= (recovery_active + resync_mark_cnt))
+ db = curr_mark_cnt - (recovery_active + resync_mark_cnt);
rt = max_sectors - resync; /* number of remaining sectors */
- sector_div(rt, db/32+1);
+ rt = div64_u64(rt, db/32+1);
rt *= dt;
rt >>= 5;
--
2.16.4
