[PATCH 4.4 022/117] md/raid: only permit hot-add of compatible integrity profiles

Greg Kroah-Hartman
2016-02-14T22:24:51Z

From: Dan Williams <dan.j.williams@intel.com>

commit 1501efadc524a0c99494b576923091589a52d2a4 upstream.

It is not safe for an integrity profile to be changed while i/o is
in-flight in the queue. Prevent adding new disks or otherwise online
spares to an array if the device has an incompatible integrity profile.

The original change to the blk_integrity_unregister implementation in
md, commmit c7bfced9a671 "md: suspend i/o during runtime
blk_integrity_unregister" introduced an immediate hang regression.

This policy of disallowing changes the integrity profile once one has
been established is shared with DM.

Here is an abbreviated log from a test run that:
1/ Creates a degraded raid1 with an integrity-enabled device (pmem0s) [ 59.076127]
2/ Tries to add an integrity-disabled device (pmem1m) [ 90.489209]
3/ Retries with an integrity-enabled device (pmem1s) [ 205.671277]

[ 59.076127] md/raid1:md0: active with 1 out of 2 mirrors
[ 59.078302] md: data integrity enabled on md0
[..]
[ 90.489209] md0: incompatible integrity profile for pmem1m
[..]
[ 205.671277] md: super_written gets error=-5
[ 205.677386] md/raid1:md0: Disk failure on pmem1m, disabling device.
[ 205.677386] md/raid1:md0: Operation continuing on 1 devices.
[ 205.683037] RAID1 conf printout:
[ 205.684699] --- wd:1 rd:2
[ 205.685972] disk 0, wo:0, o:1, dev:pmem0s
[ 205.687562] disk 1, wo:1, o:1, dev:pmem1s
[ 205.691717] md: recovery of RAID array md0

Fixes: c7bfced9a671 ("md: suspend i/o during runtime blk_integrity_unregister")
Cc: Mike Snitzer <snitzer@redhat.com>
Reported-by: NeilBrown <neilb@suse.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/md.c | 28 ++++++++++++++++------------
drivers/md/md.h | 2 +-
drivers/md/multipath.c | 6 +++---
drivers/md/raid1.c | 6 +++---
drivers/md/raid10.c | 6 +++---
5 files changed, 26 insertions(+), 22 deletions(-)

--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2017,28 +2017,32 @@ int md_integrity_register(struct mddev *
}
EXPORT_SYMBOL(md_integrity_register);

-/* Disable data integrity if non-capable/non-matching disk is being added */
-void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
+/*
+ * Attempt to add an rdev, but only if it is consistent with the current
+ * integrity profile
+ */
+int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev)
{
struct blk_integrity *bi_rdev;
struct blk_integrity *bi_mddev;
+ char name[BDEVNAME_SIZE];

if (!mddev->gendisk)
- return;
+ return 0;

bi_rdev = bdev_get_integrity(rdev->bdev);
bi_mddev = blk_get_integrity(mddev->gendisk);

if (!bi_mddev) /* nothing to do */
- return;
- if (rdev->raid_disk < 0) /* skip spares */
- return;
- if (bi_rdev && blk_integrity_compare(mddev->gendisk,
- rdev->bdev->bd_disk) >= 0)
- return;
- WARN_ON_ONCE(!mddev->suspended);
- printk(KERN_NOTICE "disabling data integrity on %s\n", mdname(mddev));
- blk_integrity_unregister(mddev->gendisk);
+ return 0;
+
+ if (blk_integrity_compare(mddev->gendisk, rdev->bdev->bd_disk) != 0) {
+ printk(KERN_NOTICE "%s: incompatible integrity profile for %s\n",
+ mdname(mddev), bdevname(rdev->bdev, name));
+ return -ENXIO;
+ }
+
+ return 0;
}
EXPORT_SYMBOL(md_integrity_add_rdev);

--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -657,7 +657,7 @@ extern void md_wait_for_blocked_rdev(str
extern void md_set_array_sectors(struct mddev *mddev, sector_t array_sectors);
extern int md_check_no_bitmap(struct mddev *mddev);
extern int md_integrity_register(struct mddev *mddev);
-extern void md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
+extern int md_integrity_add_rdev(struct md_rdev *rdev, struct mddev *mddev);
extern int strict_strtoul_scaled(const char *cp, unsigned long *res, int scale);

extern void mddev_init(struct mddev *mddev);
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -257,6 +257,9 @@ static int multipath_add_disk(struct mdd
disk_stack_limits(mddev->gendisk, rdev->bdev,
rdev->data_offset << 9);

+ err = md_integrity_add_rdev(rdev, mddev);
+ if (err)
+ break;
spin_lock_irq(&conf->device_lock);
mddev->degraded--;
rdev->raid_disk = path;
@@ -264,9 +267,6 @@ static int multipath_add_disk(struct mdd
spin_unlock_irq(&conf->device_lock);
rcu_assign_pointer(p->rdev, rdev);
err = 0;
- mddev_suspend(mddev);
- md_integrity_add_rdev(rdev, mddev);
- mddev_resume(mddev);
break;
}

--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1589,6 +1589,9 @@ static int raid1_add_disk(struct mddev *
if (mddev->recovery_disabled == conf->recovery_disabled)
return -EBUSY;

+ if (md_integrity_add_rdev(rdev, mddev))
+ return -ENXIO;
+
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;

@@ -1632,9 +1635,6 @@ static int raid1_add_disk(struct mddev *
break;
}
}
- mddev_suspend(mddev);
- md_integrity_add_rdev(rdev, mddev);
- mddev_resume(mddev);
if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
print_conf(conf);
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1698,6 +1698,9 @@ static int raid10_add_disk(struct mddev
if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
return -EINVAL;

+ if (md_integrity_add_rdev(rdev, mddev))
+ return -ENXIO;
+
if (rdev->raid_disk >= 0)
first = last = rdev->raid_disk;

@@ -1739,9 +1742,6 @@ static int raid10_add_disk(struct mddev
rcu_assign_pointer(p->rdev, rdev);
break;
}
- mddev_suspend(mddev);
- md_integrity_add_rdev(rdev, mddev);
- mddev_resume(mddev);
if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);