diff options
| -rw-r--r-- | drivers/md/raid5.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 2b521ee67df..b8a22a2205c 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -4509,7 +4509,26 @@ static int run(mddev_t *mddev) (old_disks-max_degraded)); /* here_old is the first stripe that we might need to read * from */ - if (here_new >= here_old) { + if (mddev->delta_disks == 0) { + /* We cannot be sure it is safe to start an in-place + * reshape. It is only safe if user-space if monitoring + * and taking constant backups. + * mdadm always starts a situation like this in + * readonly mode so it can take control before + * allowing any writes. So just check for that. + */ + if ((here_new * mddev->new_chunk_sectors != + here_old * mddev->chunk_sectors) || + mddev->ro == 0) { + printk(KERN_ERR "raid5: in-place reshape must be started" + " in read-only mode - aborting\n"); + return -EINVAL; + } + } else if (mddev->delta_disks < 0 + ? (here_new * mddev->new_chunk_sectors <= + here_old * mddev->chunk_sectors) + : (here_new * mddev->new_chunk_sectors >= + here_old * mddev->chunk_sectors)) { /* Reading from the same stripe as writing to - bad */ printk(KERN_ERR "raid5: reshape_position too early for " "auto-recovery - aborting.\n"); |