Btrfs: add ioctl to get and reset the device stats
An ioctl interface is added to get the device statistic counters.
A second ioctl is added to atomically get and reset these counters.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 2915521..a112b75 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4673,3 +4673,37 @@
btrfs_dev_stat_read(dev,
BTRFS_DEV_STAT_GENERATION_ERRS));
}
+
+int btrfs_get_dev_stats(struct btrfs_root *root,
+ struct btrfs_ioctl_get_dev_stats *stats,
+ int reset_after_read)
+{
+ struct btrfs_device *dev;
+ struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
+ int i;
+
+ mutex_lock(&fs_devices->device_list_mutex);
+ dev = btrfs_find_device(root, stats->devid, NULL, NULL);
+ mutex_unlock(&fs_devices->device_list_mutex);
+
+ if (!dev) {
+ printk(KERN_WARNING
+ "btrfs: get dev_stats failed, device not found\n");
+ return -ENODEV;
+ } else if (reset_after_read) {
+ for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
+ if (stats->nr_items > i)
+ stats->values[i] =
+ btrfs_dev_stat_read_and_reset(dev, i);
+ else
+ btrfs_dev_stat_reset(dev, i);
+ }
+ } else {
+ for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
+ if (stats->nr_items > i)
+ stats->values[i] = btrfs_dev_stat_read(dev, i);
+ }
+ if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
+ stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
+ return 0;
+}