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@xxxxxxxxxxxx>
---
fs/btrfs/ioctl.h | 3 ++-
fs/btrfs/super.c | 7 +++++++
fs/btrfs/volumes.c | 9 ++++++++-
fs/btrfs/volumes.h | 1 +
4 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 497c530..34317cf 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -363,5 +363,6 @@ struct btrfs_ioctl_get_dev_stats {
struct btrfs_ioctl_get_dev_stats)
#define BTRFS_IOC_GET_AND_RESET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 53, \
struct btrfs_ioctl_get_dev_stats)
-
+#define BTRFS_IOC_DEVICES_READY _IOW(BTRFS_IOCTL_MAGIC, 54, \
+ struct btrfs_ioctl_vol_args)
#endif
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 23fc7e8..347ccd8 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1458,6 +1458,13 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
break;
+ case BTRFS_IOC_DEVICES_READY:
+ ret = btrfs_scan_one_device(vol->name, FMODE_READ,
+ &btrfs_fs_type, &fs_devices);
+ if (ret)
+ break;
+ ret = !(fs_devices->num_devices == fs_devices->total_devices);
+ break;
}
kfree(vol);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 3f292cf..a505627 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);
@@ -1749,6 +1755,7 @@ 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;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 74366f2..a3c5d5c 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -126,6 +126,7 @@ struct btrfs_fs_devices {
u64 missing_devices;
u64 total_rw_bytes;
u64 num_can_discard;
+ u64 total_devices;
struct block_device *latest_bdev;
/* all of the devices in the FS, protected by a mutex
--
1.7.7.6
--
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