forked from Minki/linux
md/raid10: locking changes for 'enough()'.
As 'enough' accesses conf->prev and conf->geo, which can change spontanously, it should guard against changes. This can be done with device_lock as start_reshape holds device_lock while updating 'geo' and end_reshape holds it while updating 'prev'. So 'error' needs to hold 'device_lock'. On the other hand, raid10_end_read_request knows which of the two it really wants to access, and as it is an active request on that one, the value cannot change underneath it. So change _enough to take flag rather than a pointer, pass the appropriate flag from raid10_end_read_request(), and remove the locking. All other calls to 'enough' are made with reconfig_mutex held, so neither 'prev' nor 'geo' can change. Signed-off-by: NeilBrown <neilb@suse.de>
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635f6416a2
@ -97,7 +97,7 @@ static int max_queued_requests = 1024;
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static void allow_barrier(struct r10conf *conf);
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static void lower_barrier(struct r10conf *conf);
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static int enough(struct r10conf *conf, int ignore);
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static int _enough(struct r10conf *conf, int previous, int ignore);
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static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
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int *skipped);
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static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
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@ -392,11 +392,9 @@ static void raid10_end_read_request(struct bio *bio, int error)
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* than fail the last device. Here we redefine
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* "uptodate" to mean "Don't want to retry"
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*/
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unsigned long flags;
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spin_lock_irqsave(&conf->device_lock, flags);
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if (!enough(conf, rdev->raid_disk))
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if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
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rdev->raid_disk))
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uptodate = 1;
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spin_unlock_irqrestore(&conf->device_lock, flags);
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}
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if (uptodate) {
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raid_end_bio_io(r10_bio);
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@ -1632,9 +1630,17 @@ static void status(struct seq_file *seq, struct mddev *mddev)
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* Don't consider the device numbered 'ignore'
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* as we might be about to remove it.
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*/
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static int _enough(struct r10conf *conf, struct geom *geo, int ignore)
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static int _enough(struct r10conf *conf, int previous, int ignore)
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{
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int first = 0;
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int disks, ncopies;
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if (previous) {
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disks = conf->prev.raid_disks;
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ncopies = conf->prev.near_copies;
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} else {
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disks = conf->geo.raid_disks;
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ncopies = conf->geo.near_copies;
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}
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do {
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int n = conf->copies;
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@ -1644,25 +1650,31 @@ static int _enough(struct r10conf *conf, struct geom *geo, int ignore)
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if (conf->mirrors[this].rdev &&
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this != ignore)
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cnt++;
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this = (this+1) % geo->raid_disks;
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this = (this+1) % disks;
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}
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if (cnt == 0)
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return 0;
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first = (first + geo->near_copies) % geo->raid_disks;
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first = (first + ncopies) % disks;
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} while (first != 0);
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return 1;
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}
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static int enough(struct r10conf *conf, int ignore)
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{
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return _enough(conf, &conf->geo, ignore) &&
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_enough(conf, &conf->prev, ignore);
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/* when calling 'enough', both 'prev' and 'geo' must
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* be stable.
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* This is ensured if ->reconfig_mutex or ->device_lock
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* is held.
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*/
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return _enough(conf, 0, ignore) &&
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_enough(conf, 1, ignore);
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}
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static void error(struct mddev *mddev, struct md_rdev *rdev)
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{
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char b[BDEVNAME_SIZE];
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struct r10conf *conf = mddev->private;
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unsigned long flags;
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/*
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* If it is not operational, then we have already marked it as dead
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@ -1670,18 +1682,18 @@ static void error(struct mddev *mddev, struct md_rdev *rdev)
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* next level up know.
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* else mark the drive as failed
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*/
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spin_lock_irqsave(&conf->device_lock, flags);
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if (test_bit(In_sync, &rdev->flags)
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&& !enough(conf, rdev->raid_disk))
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&& !enough(conf, rdev->raid_disk)) {
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/*
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* Don't fail the drive, just return an IO error.
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*/
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return;
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if (test_and_clear_bit(In_sync, &rdev->flags)) {
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unsigned long flags;
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spin_lock_irqsave(&conf->device_lock, flags);
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mddev->degraded++;
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spin_unlock_irqrestore(&conf->device_lock, flags);
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/*
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return;
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}
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if (test_and_clear_bit(In_sync, &rdev->flags)) {
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mddev->degraded++;
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/*
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* if recovery is running, make sure it aborts.
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*/
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set_bit(MD_RECOVERY_INTR, &mddev->recovery);
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@ -1689,6 +1701,7 @@ static void error(struct mddev *mddev, struct md_rdev *rdev)
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set_bit(Blocked, &rdev->flags);
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set_bit(Faulty, &rdev->flags);
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set_bit(MD_CHANGE_DEVS, &mddev->flags);
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spin_unlock_irqrestore(&conf->device_lock, flags);
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printk(KERN_ALERT
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"md/raid10:%s: Disk failure on %s, disabling device.\n"
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"md/raid10:%s: Operation continuing on %d devices.\n",
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@ -1791,7 +1804,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
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* very different from resync
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*/
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return -EBUSY;
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if (rdev->saved_raid_disk < 0 && !_enough(conf, &conf->prev, -1))
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if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
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return -EINVAL;
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if (rdev->raid_disk >= 0)
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