Btrfs: add DEVICE_READY ioctl
This will be used in conjunction with btrfs device ready <dev>. This is
needed for initrd's to have a nice and lightweight way to tell if all of the
devices needed for a file system are in the cache currently. This keeps
them from having to do mount+sleep loops waiting for devices to show up.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 957bf39..39a0d04 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -429,6 +429,7 @@
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 ret;
u64 devid;
u64 transid;
+ u64 total_devices;
flags |= FMODE_EXCL;
bdev = blkdev_get_by_path(path, flags, holder);
@@ -760,6 +762,7 @@
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 @@
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 @@
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 @@
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);
@@ -1749,6 +1755,7 @@
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;