Commit 96de1e66 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: fix some locking and module refcounting issues with md's use of sysfs 



1/ I really should be using the __ATTR macros for defining attributes, so
   that the .owner field get set properly, otherwise modules can be removed
   while sysfs files are open.  This also involves some name changes of _show
   routines.

2/ Always lock the mddev (against reconfiguration) for all sysfs attribute
   access.  This easily avoid certain races and is completely consistant with
   other interfaces (ioctl and /proc/mdstat both always lock against
   reconfiguration).

3/ raid5 attributes must check that the 'conf' structure actually exists
   (the array could have been stopped while an attribute file was open).

4/ A missing 'kfree' from when the raid5_conf_t was converted to have a
   kobject embedded, and then converted back again.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3855ad9f

drivers/md/md.c

+28 −34
Original line number Diff line number Diff line
@@ -1504,7 +1504,7 @@ struct rdev_sysfs_entry { 
};



static ssize_t

rdev_show_state(mdk_rdev_t *rdev, char *page)

state_show(mdk_rdev_t *rdev, char *page)

{

	char *sep = "";

	int len=0;
@@ -1525,13 +1525,11 @@ rdev_show_state(mdk_rdev_t *rdev, char *page) 
	return len+sprintf(page+len, "\n");

}



static struct rdev_sysfs_entry rdev_state = {

	.attr = {.name = "state", .mode = S_IRUGO },

	.show = rdev_show_state,

};

static struct rdev_sysfs_entry

rdev_state = __ATTR_RO(state);



static ssize_t

rdev_show_super(mdk_rdev_t *rdev, char *page)

super_show(mdk_rdev_t *rdev, char *page)

{

	if (rdev->sb_loaded && rdev->sb_size) {

		memcpy(page, page_address(rdev->sb_page), rdev->sb_size);
@@ -1539,10 +1537,8 @@ rdev_show_super(mdk_rdev_t *rdev, char *page) 
	} else

		return 0;

}

static struct rdev_sysfs_entry rdev_super = {

	.attr = {.name = "super", .mode = S_IRUGO },

	.show = rdev_show_super,

};

static struct rdev_sysfs_entry rdev_super = __ATTR_RO(super);



static struct attribute *rdev_default_attrs[] = {

	&rdev_state.attr,

	&rdev_super.attr,
@@ -1728,7 +1724,7 @@ static void analyze_sbs(mddev_t * mddev) 
}



static ssize_t

md_show_level(mddev_t *mddev, char *page)

level_show(mddev_t *mddev, char *page)

{

	mdk_personality_t *p = mddev->pers;

	if (p == NULL)
@@ -1739,21 +1735,15 @@ md_show_level(mddev_t *mddev, char *page) 
		return sprintf(page, "%s\n", p->name);

}



static struct md_sysfs_entry md_level = {

	.attr = {.name = "level", .mode = S_IRUGO },

	.show = md_show_level,

};

static struct md_sysfs_entry md_level = __ATTR_RO(level);



static ssize_t

md_show_rdisks(mddev_t *mddev, char *page)

raid_disks_show(mddev_t *mddev, char *page)

{

	return sprintf(page, "%d\n", mddev->raid_disks);

}



static struct md_sysfs_entry md_raid_disks = {

	.attr = {.name = "raid_disks", .mode = S_IRUGO },

	.show = md_show_rdisks,

};

static struct md_sysfs_entry md_raid_disks = __ATTR_RO(raid_disks);



static ssize_t

md_show_scan(mddev_t *mddev, char *page)
@@ -1782,10 +1772,10 @@ md_store_scan(mddev_t *mddev, const char *page, size_t len) 
	if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||

	    test_bit(MD_RECOVERY_NEEDED, &mddev->recovery))

		return -EBUSY;

	down(&mddev->reconfig_sem);



	if (mddev->pers && mddev->pers->sync_request)

		canscan=1;

	up(&mddev->reconfig_sem);



	if (!canscan)

		return -EINVAL;
@@ -1801,22 +1791,18 @@ md_store_scan(mddev_t *mddev, const char *page, size_t len) 
}



static ssize_t

md_show_mismatch(mddev_t *mddev, char *page)

mismatch_cnt_show(mddev_t *mddev, char *page)

{

	return sprintf(page, "%llu\n",

		       (unsigned long long) mddev->resync_mismatches);

}



static struct md_sysfs_entry md_scan_mode = {

	.attr = {.name = "scan_mode", .mode = S_IRUGO|S_IWUSR },

	.show = md_show_scan,

	.store = md_store_scan,

};

static struct md_sysfs_entry

md_scan_mode = __ATTR(scan_mode, S_IRUGO|S_IWUSR, md_show_scan, md_store_scan);



static struct md_sysfs_entry md_mismatches = {

	.attr = {.name = "mismatch_cnt", .mode = S_IRUGO },

	.show = md_show_mismatch,

};



static struct md_sysfs_entry

md_mismatches = __ATTR_RO(mismatch_cnt);



static struct attribute *md_default_attrs[] = {

	&md_level.attr,
@@ -1831,10 +1817,14 @@ md_attr_show(struct kobject *kobj, struct attribute *attr, char *page) 
{

	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);

	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);

	ssize_t rv;



	if (!entry->show)

		return -EIO;

	return entry->show(mddev, page);

	mddev_lock(mddev);

	rv = entry->show(mddev, page);

	mddev_unlock(mddev);

	return rv;

}



static ssize_t
@@ -1843,10 +1833,14 @@ md_attr_store(struct kobject *kobj, struct attribute *attr, 
{

	struct md_sysfs_entry *entry = container_of(attr, struct md_sysfs_entry, attr);

	mddev_t *mddev = container_of(kobj, struct mddev_s, kobj);

	ssize_t rv;



	if (!entry->store)

		return -EIO;

	return entry->store(mddev, page, length);

	mddev_lock(mddev);

	rv = entry->store(mddev, page, length);

	mddev_unlock(mddev);

	return rv;

}



static void md_free(struct kobject *ko)

drivers/md/raid5.c

+18 −12
Original line number Diff line number Diff line
@@ -1746,7 +1746,10 @@ static ssize_t 
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)

{

	raid5_conf_t *conf = mddev_to_conf(mddev);

	if (conf)

		return sprintf(page, "%d\n", conf->max_nr_stripes);

	else

		return 0;

}



static ssize_t
@@ -1757,6 +1760,8 @@ raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 
	int new;

	if (len >= PAGE_SIZE)

		return -EINVAL;

	if (!conf)

		return -ENODEV;



	new = simple_strtoul(page, &end, 10);

	if (!*page || (*end && *end != '\n') )
@@ -1777,23 +1782,23 @@ raid5_store_stripe_cache_size(mddev_t *mddev, const char *page, size_t len) 
	return len;

}



static struct md_sysfs_entry raid5_stripecache_size = {

	.attr = {.name = "stripe_cache_size", .mode = S_IRUGO | S_IWUSR },

	.show = raid5_show_stripe_cache_size,

	.store = raid5_store_stripe_cache_size,

};

static struct md_sysfs_entry

raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,

				raid5_show_stripe_cache_size,

				raid5_store_stripe_cache_size);



static ssize_t

raid5_show_stripe_cache_active(mddev_t *mddev, char *page)

stripe_cache_active_show(mddev_t *mddev, char *page)

{

	raid5_conf_t *conf = mddev_to_conf(mddev);

	if (conf)

		return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));

	else

		return 0;

}



static struct md_sysfs_entry raid5_stripecache_active = {

	.attr = {.name = "stripe_cache_active", .mode = S_IRUGO},

	.show = raid5_show_stripe_cache_active,

};

static struct md_sysfs_entry

raid5_stripecache_active = __ATTR_RO(stripe_cache_active);



static struct attribute *raid5_attrs[] =  {

	&raid5_stripecache_size.attr,
@@ -1981,6 +1986,7 @@ static int stop(mddev_t *mddev) 
	free_pages((unsigned long) conf->stripe_hashtbl, HASH_PAGES_ORDER);

	blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/

	sysfs_remove_group(&mddev->kobj, &raid5_attrs_group);

	kfree(conf);

	mddev->private = NULL;

	return 0;

}

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