1 files changed, 18 insertions, 11 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ecaad40e7ef4..e86ae04abe6a 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -429,6 +429,7 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
         mutex_init(&fs_devices->device_list_mutex);
         fs_devices->latest_devid = orig->latest_devid;
         fs_devices->latest_trans = orig->latest_trans;
+        fs_devices->total_devices = orig->total_devices;
         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 
         /* We have held the volume lock, it is safe to get the devices. */
@@ -739,6 +740,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
         int ret;
         u64 devid;
         u64 transid;
+        u64 total_devices;
 
         flags |= FMODE_EXCL;
         bdev = blkdev_get_by_path(path, flags, holder);
@@ -760,6 +762,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
         disk_super = (struct btrfs_super_block *)bh->b_data;
         devid = btrfs_stack_device_id(&disk_super->dev_item);
         transid = btrfs_super_generation(disk_super);
+        total_devices = btrfs_super_num_devices(disk_super);
         if (disk_super->label[0])
                 printk(KERN_INFO "device label %s ", disk_super->label);
         else
@@ -767,7 +770,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
         printk(KERN_CONT "devid %llu transid %llu %s\n",
                (unsigned long long)devid, (unsigned long long)transid, path);
         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
-
+        if (!ret && fs_devices_ret)
+                (*fs_devices_ret)->total_devices = total_devices;
         brelse(bh);
 error_close:
         mutex_unlock(&uuid_mutex);
@@ -1433,6 +1437,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
         list_del_rcu(&device->dev_list);
 
         device->fs_devices->num_devices--;
+        device->fs_devices->total_devices--;
 
         if (device->missing)
                 root->fs_info->fs_devices->missing_devices--;
@@ -1550,6 +1555,7 @@ static int btrfs_prepare_sprout(struct btrfs_root *root)
         fs_devices->seeding = 0;
         fs_devices->num_devices = 0;
         fs_devices->open_devices = 0;
+        fs_devices->total_devices = 0;
         fs_devices->seed = seed_devices;
 
         generate_random_uuid(fs_devices->fsid);
@@ -1738,10 +1744,6 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 
         device->fs_devices = root->fs_info->fs_devices;
 
-        /*
-         * we don't want write_supers to jump in here with our device
-         * half setup
-         */
         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
         list_add(&device->dev_alloc_list,
@@ -1749,6 +1751,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         root->fs_info->fs_devices->num_devices++;
         root->fs_info->fs_devices->open_devices++;
         root->fs_info->fs_devices->rw_devices++;
+        root->fs_info->fs_devices->total_devices++;
         if (device->can_discard)
                 root->fs_info->fs_devices->num_can_discard++;
         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
@@ -4736,9 +4739,6 @@ int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
                 key.offset = device->devid;
                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
                 if (ret) {
-                        printk_in_rcu(KERN_WARNING "btrfs: no dev_stats entry found for device %s (devid %llu) (OK on first mount after mkfs)\n",
-                                      rcu_str_deref(device->name),
-                                      (unsigned long long)device->devid);
                         __btrfs_reset_dev_stats(device);
                         device->dev_stats_valid = 1;
                         btrfs_release_path(path);
@@ -4880,6 +4880,14 @@ void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
 
 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
 {
+        int i;
+
+        for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
+                if (btrfs_dev_stat_read(dev, i) != 0)
+                        break;
+        if (i == BTRFS_DEV_STAT_VALUES_MAX)
+                return; /* all values == 0, suppress message */
+
         printk_in_rcu(KERN_INFO "btrfs: bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u\n",
                rcu_str_deref(dev->name),
                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
@@ -4890,8 +4898,7 @@ static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
 }
 
 int btrfs_get_dev_stats(struct btrfs_root *root,
-                        struct btrfs_ioctl_get_dev_stats *stats,
-                        int reset_after_read)
+                        struct btrfs_ioctl_get_dev_stats *stats)
 {
         struct btrfs_device *dev;
         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
@@ -4909,7 +4916,7 @@ int btrfs_get_dev_stats(struct btrfs_root *root,
                 printk(KERN_WARNING
                        "btrfs: get dev_stats failed, not yet valid\n");
                 return -ENODEV;
-        } else if (reset_after_read) {
+        } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
                         if (stats->nr_items > i)
                                 stats->values[i] =