renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-21 03:33:59 +08:00
Code

md/raid5: handle possible race as reshape completes.

Browse Source 
It is possible (though unlikely) for a reshape to be
interrupted between the time that end_reshape is called
and the time when raid5_finish_reshape is called.

This can leave conf->reshape_progress set to MaxSector,
but mddev->reshape_position not.

This combination confused reshape_request() when ->reshape_backwards.
As conf->reshape_progress is so high, it seems the reshape hasn't
really begun.  But assuming MaxSector is a valid address only
leads to sorrow.

So ensure reshape_position and reshape_progress both agree,
and add an extra check in reshape_request() just in case they don't.

Signed-off-by: NeilBrown <neilb@suse.com>
This commit is contained in:
NeilBrown 2015-07-24 13:30:32 +10:00
parent 5ed1df2eac
commit 6cbd81487f
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/md/raid5.c
View File

@ -5355,6 +5355,10 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *sk
conf->reshape_progress < raid5_size(mddev, 0, 0)) {
sector_nr = raid5_size(mddev, 0, 0)
- conf->reshape_progress;
} else if (mddev->reshape_backwards &&
conf->reshape_progress == MaxSector) {
/* shouldn't happen, but just in case, finish up.*/
sector_nr = MaxSector;
} else if (!mddev->reshape_backwards &&
conf->reshape_progress > 0)
sector_nr = conf->reshape_progress;
@ -7446,6 +7450,7 @@ static void end_reshape(struct r5conf *conf)
rdev->data_offset = rdev->new_data_offset;
smp_wmb();
conf->reshape_progress = MaxSector;
conf->mddev->reshape_position = MaxSector;
spin_unlock_irq(&conf->device_lock);
wake_up(&conf->wait_for_overlap);