[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: Neil Brown <neilb@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2b59289..b2d8813 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1504,7 +1504,7 @@
};
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 @@
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 @@
} 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 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 @@
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 @@
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 @@
}
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 @@
{
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 @@
{
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)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 51003b0..e2a4028 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1746,7 +1746,10 @@
raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
{
raid5_conf_t *conf = mddev_to_conf(mddev);
- return sprintf(page, "%d\n", conf->max_nr_stripes);
+ if (conf)
+ return sprintf(page, "%d\n", conf->max_nr_stripes);
+ else
+ return 0;
}
static ssize_t
@@ -1757,6 +1760,8 @@
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 @@
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);
- return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
+ 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 @@
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;
}