md: make ->congested robust against personality changes.
There is currently no locking around calls to the 'congested'
bdi function. If called at an awkward time while an array is
being converted from one level (or personality) to another, there
is a tiny chance of running code in an unreferenced module etc.
So add a 'congested' function to the md_personality operations
structure, and call it with appropriate locking from a central
'mddev_congested'.
When the array personality is changing the array will be 'suspended'
so no IO is processed.
If mddev_congested detects this, it simply reports that the
array is congested, which is a safe guess.
As mddev_suspend calls synchronize_rcu(), mddev_congested can
avoid races by included the whole call inside an rcu_read_lock()
region.
This require that the congested functions for all subordinate devices
can be run under rcu_lock. Fortunately this is the case.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 07c0fa0..777d9ba 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -746,13 +746,7 @@
{
struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
- if (rs->raid_type->level == 1)
- return md_raid1_congested(&rs->md, bits);
-
- if (rs->raid_type->level == 10)
- return md_raid10_congested(&rs->md, bits);
-
- return md_raid5_congested(&rs->md, bits);
+ return mddev_congested(&rs->md, bits);
}
/*
diff --git a/drivers/md/linear.c b/drivers/md/linear.c
index 64713b7..0510851 100644
--- a/drivers/md/linear.c
+++ b/drivers/md/linear.c
@@ -97,15 +97,11 @@
return maxsectors << 9;
}
-static int linear_congested(void *data, int bits)
+static int linear_congested(struct mddev *mddev, int bits)
{
- struct mddev *mddev = data;
struct linear_conf *conf;
int i, ret = 0;
- if (mddev_congested(mddev, bits))
- return 1;
-
rcu_read_lock();
conf = rcu_dereference(mddev->private);
@@ -218,8 +214,6 @@
md_set_array_sectors(mddev, linear_size(mddev, 0, 0));
blk_queue_merge_bvec(mddev->queue, linear_mergeable_bvec);
- mddev->queue->backing_dev_info.congested_fn = linear_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
ret = md_integrity_register(mddev);
if (ret) {
@@ -366,6 +360,7 @@
.status = linear_status,
.hot_add_disk = linear_add,
.size = linear_size,
+ .congested = linear_congested,
};
static int __init linear_init (void)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 17e7fd7..d45f52e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -321,9 +321,23 @@
int mddev_congested(struct mddev *mddev, int bits)
{
- return mddev->suspended;
+ struct md_personality *pers = mddev->pers;
+ int ret = 0;
+
+ rcu_read_lock();
+ if (mddev->suspended)
+ ret = 1;
+ else if (pers && pers->congested)
+ ret = pers->congested(mddev, bits);
+ rcu_read_unlock();
+ return ret;
}
-EXPORT_SYMBOL(mddev_congested);
+EXPORT_SYMBOL_GPL(mddev_congested);
+static int md_congested(void *data, int bits)
+{
+ struct mddev *mddev = data;
+ return mddev_congested(mddev, bits);
+}
/*
* Generic flush handling for md
@@ -4908,6 +4922,10 @@
bitmap_destroy(mddev);
return err;
}
+ if (mddev->queue) {
+ mddev->queue->backing_dev_info.congested_data = mddev;
+ mddev->queue->backing_dev_info.congested_fn = md_congested;
+ }
if (mddev->pers->sync_request) {
if (mddev->kobj.sd &&
sysfs_create_group(&mddev->kobj, &md_redundancy_group))
diff --git a/drivers/md/md.h b/drivers/md/md.h
index f0d15bd..f260228 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -496,6 +496,9 @@
* array.
*/
void *(*takeover) (struct mddev *mddev);
+ /* congested implements bdi.congested_fn().
+ * Will not be called while array is 'suspended' */
+ int (*congested)(struct mddev *mddev, int bits);
};
struct md_sysfs_entry {
diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 399272f..fedb1b3 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -153,15 +153,11 @@
seq_printf (seq, "]");
}
-static int multipath_congested(void *data, int bits)
+static int multipath_congested(struct mddev *mddev, int bits)
{
- struct mddev *mddev = data;
struct mpconf *conf = mddev->private;
int i, ret = 0;
- if (mddev_congested(mddev, bits))
- return 1;
-
rcu_read_lock();
for (i = 0; i < mddev->raid_disks ; i++) {
struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
@@ -489,9 +485,6 @@
*/
md_set_array_sectors(mddev, multipath_size(mddev, 0, 0));
- mddev->queue->backing_dev_info.congested_fn = multipath_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
-
if (md_integrity_register(mddev))
goto out_free_conf;
@@ -533,6 +526,7 @@
.hot_add_disk = multipath_add_disk,
.hot_remove_disk= multipath_remove_disk,
.size = multipath_size,
+ .congested = multipath_congested,
};
static int __init multipath_init (void)
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index ba6b85d..4b521ea 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -25,17 +25,13 @@
#include "raid0.h"
#include "raid5.h"
-static int raid0_congested(void *data, int bits)
+static int raid0_congested(struct mddev *mddev, int bits)
{
- struct mddev *mddev = data;
struct r0conf *conf = mddev->private;
struct md_rdev **devlist = conf->devlist;
int raid_disks = conf->strip_zone[0].nb_dev;
int i, ret = 0;
- if (mddev_congested(mddev, bits))
- return 1;
-
for (i = 0; i < raid_disks && !ret ; i++) {
struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
@@ -263,8 +259,6 @@
mdname(mddev),
(unsigned long long)smallest->sectors);
}
- mddev->queue->backing_dev_info.congested_fn = raid0_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
/*
* now since we have the hard sector sizes, we can make sure
@@ -729,6 +723,7 @@
.size = raid0_size,
.takeover = raid0_takeover,
.quiesce = raid0_quiesce,
+ .congested = raid0_congested,
};
static int __init raid0_init (void)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 40b35be..9ad7ce7 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -734,7 +734,7 @@
}
-int md_raid1_congested(struct mddev *mddev, int bits)
+static int raid1_congested(struct mddev *mddev, int bits)
{
struct r1conf *conf = mddev->private;
int i, ret = 0;
@@ -763,15 +763,6 @@
rcu_read_unlock();
return ret;
}
-EXPORT_SYMBOL_GPL(md_raid1_congested);
-
-static int raid1_congested(void *data, int bits)
-{
- struct mddev *mddev = data;
-
- return mddev_congested(mddev, bits) ||
- md_raid1_congested(mddev, bits);
-}
static void flush_pending_writes(struct r1conf *conf)
{
@@ -2955,8 +2946,6 @@
md_set_array_sectors(mddev, raid1_size(mddev, 0, 0));
if (mddev->queue) {
- mddev->queue->backing_dev_info.congested_fn = raid1_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
blk_queue_merge_bvec(mddev->queue, raid1_mergeable_bvec);
if (discard_supported)
@@ -3193,6 +3182,7 @@
.check_reshape = raid1_reshape,
.quiesce = raid1_quiesce,
.takeover = raid1_takeover,
+ .congested = raid1_congested,
};
static int __init raid_init(void)
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index 33bda55..14ebb28 100644
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -170,7 +170,4 @@
*/
#define R1BIO_MadeGood 7
#define R1BIO_WriteError 8
-
-extern int md_raid1_congested(struct mddev *mddev, int bits);
-
#endif
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 32e282f..fb6b886 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -910,7 +910,7 @@
return rdev;
}
-int md_raid10_congested(struct mddev *mddev, int bits)
+static int raid10_congested(struct mddev *mddev, int bits)
{
struct r10conf *conf = mddev->private;
int i, ret = 0;
@@ -934,15 +934,6 @@
rcu_read_unlock();
return ret;
}
-EXPORT_SYMBOL_GPL(md_raid10_congested);
-
-static int raid10_congested(void *data, int bits)
-{
- struct mddev *mddev = data;
-
- return mddev_congested(mddev, bits) ||
- md_raid10_congested(mddev, bits);
-}
static void flush_pending_writes(struct r10conf *conf)
{
@@ -3757,8 +3748,6 @@
if (mddev->queue) {
int stripe = conf->geo.raid_disks *
((mddev->chunk_sectors << 9) / PAGE_SIZE);
- mddev->queue->backing_dev_info.congested_fn = raid10_congested;
- mddev->queue->backing_dev_info.congested_data = mddev;
/* Calculate max read-ahead size.
* We need to readahead at least twice a whole stripe....
@@ -4727,6 +4716,7 @@
.check_reshape = raid10_check_reshape,
.start_reshape = raid10_start_reshape,
.finish_reshape = raid10_finish_reshape,
+ .congested = raid10_congested,
};
static int __init raid_init(void)
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 157d69e..5ee6473 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -150,7 +150,4 @@
*/
R10BIO_Previous,
};
-
-extern int md_raid10_congested(struct mddev *mddev, int bits);
-
#endif
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a03cf2d..502a908 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4149,7 +4149,7 @@
}
}
-int md_raid5_congested(struct mddev *mddev, int bits)
+static int raid5_congested(struct mddev *mddev, int bits)
{
struct r5conf *conf = mddev->private;
@@ -4166,15 +4166,6 @@
return 0;
}
-EXPORT_SYMBOL_GPL(md_raid5_congested);
-
-static int raid5_congested(void *data, int bits)
-{
- struct mddev *mddev = data;
-
- return mddev_congested(mddev, bits) ||
- md_raid5_congested(mddev, bits);
-}
/* We want read requests to align with chunks where possible,
* but write requests don't need to.
@@ -6248,9 +6239,6 @@
blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
- mddev->queue->backing_dev_info.congested_data = mddev;
- mddev->queue->backing_dev_info.congested_fn = raid5_congested;
-
chunk_size = mddev->chunk_sectors << 9;
blk_queue_io_min(mddev->queue, chunk_size);
blk_queue_io_opt(mddev->queue, chunk_size *
@@ -6333,8 +6321,6 @@
struct r5conf *conf = mddev->private;
md_unregister_thread(&mddev->thread);
- if (mddev->queue)
- mddev->queue->backing_dev_info.congested_fn = NULL;
free_conf(conf);
mddev->private = NULL;
mddev->to_remove = &raid5_attrs_group;
@@ -7126,6 +7112,7 @@
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid6_takeover,
+ .congested = raid5_congested,
};
static struct md_personality raid5_personality =
{
@@ -7148,6 +7135,7 @@
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
+ .congested = raid5_congested,
};
static struct md_personality raid4_personality =
@@ -7171,6 +7159,7 @@
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid4_takeover,
+ .congested = raid5_congested,
};
static int __init raid5_init(void)
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index d59f5ca..983e18a 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -558,7 +558,6 @@
return layout >= 8 && layout <= 10;
}
-extern int md_raid5_congested(struct mddev *mddev, int bits);
extern void md_raid5_kick_device(struct r5conf *conf);
extern int raid5_set_cache_size(struct mddev *mddev, int size);
#endif