Btrfs: Add new ioctl to add devices

Signed-off-by: Chris Mason <chris.mason@oracle.com>

6 files changed, 108 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index ac7106ec5357..b9257b37bb96 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -551,6 +551,8 @@ struct btrfs_fs_info {
         u64 data_alloc_profile;
         u64 metadata_alloc_profile;
         u64 system_alloc_profile;
+
+        void *bdev_holder;
 };
 
 /*
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ab707c0930df..1a74b5018699 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3070,6 +3070,27 @@ static int btrfs_ioctl_defrag(struct file *file)
         return 0;
 }
 
+long btrfs_ioctl_add_dev(struct btrfs_root *root, void __user *arg)
+{
+        struct btrfs_ioctl_vol_args *vol_args;
+        int ret;
+
+        vol_args = kmalloc(sizeof(*vol_args), GFP_NOFS);
+
+        if (!vol_args)
+                return -ENOMEM;
+
+        if (copy_from_user(vol_args, arg, sizeof(*vol_args))) {
+                ret = -EFAULT;
+                goto out;
+        }
+        ret = btrfs_init_new_device(root, vol_args->name);
+
+out:
+        kfree(vol_args);
+        return ret;
+}
+
 long btrfs_ioctl(struct file *file, unsigned int
                 cmd, unsigned long arg)
 {
@@ -3082,6 +3103,8 @@ long btrfs_ioctl(struct file *file, unsigned int
                 return btrfs_ioctl_defrag(file);
         case BTRFS_IOC_RESIZE:
                 return btrfs_ioctl_resize(root, (void __user *)arg);
+        case BTRFS_IOC_ADD_DEV:
+                return btrfs_ioctl_add_dev(root, (void __user *)arg);
         }
 
         return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 4551e82013c8..8ad35fc4ba56 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -36,4 +36,10 @@ struct btrfs_ioctl_vol_args {
                                    struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
                                    struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_ADD_DEV _IOW(BTRFS_IOCTL_MAGIC, 10, \
+                                   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_RM_DEV _IOW(BTRFS_IOCTL_MAGIC, 11, \
+                                   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_BALANCE _IOW(BTRFS_IOCTL_MAGIC, 12, \
+                                   struct btrfs_ioctl_vol_args)
 #endif
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 892864906880..7153dfaa3404 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -388,6 +388,7 @@ int btrfs_get_sb_bdev(struct file_system_type *fs_type,
                         goto error;
                 }
 
+                btrfs_sb(s)->fs_info->bdev_holder = fs_type;
                 s->s_flags |= MS_ACTIVE;
         }
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a2c56de1548a..b93c15aa17db 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -19,6 +19,7 @@
 #include <linux/bio.h>
 #include <linux/buffer_head.h>
 #include <linux/blkdev.h>
+#include <linux/random.h>
 #include <asm/div64.h>
 #include "ctree.h"
 #include "extent_map.h"
@@ -592,6 +593,80 @@ out:
         return ret;
 }
 
+int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
+{
+        struct btrfs_trans_handle *trans;
+        struct btrfs_device *device;
+        struct block_device *bdev;
+        struct list_head *cur;
+        struct list_head *devices;
+        u64 total_bytes;
+        int ret = 0;
+
+
+        bdev = open_bdev_excl(device_path, 0, root->fs_info->bdev_holder);
+        if (!bdev) {
+                return -EIO;
+        }
+        mutex_lock(&root->fs_info->fs_mutex);
+        trans = btrfs_start_transaction(root, 1);
+        devices = &root->fs_info->fs_devices->devices;
+        list_for_each(cur, devices) {
+                device = list_entry(cur, struct btrfs_device, dev_list);
+                if (device->bdev == bdev) {
+                        ret = -EEXIST;
+                        goto out;
+                }
+        }
+
+        device = kzalloc(sizeof(*device), GFP_NOFS);
+        if (!device) {
+                /* we can safely leave the fs_devices entry around */
+                ret = -ENOMEM;
+                goto out_close_bdev;
+        }
+
+        device->barriers = 1;
+        generate_random_uuid(device->uuid);
+        spin_lock_init(&device->io_lock);
+        device->name = kstrdup(device_path, GFP_NOFS);
+        if (!device->name) {
+                kfree(device);
+                goto out_close_bdev;
+        }
+        device->io_width = root->sectorsize;
+        device->io_align = root->sectorsize;
+        device->sector_size = root->sectorsize;
+        device->total_bytes = i_size_read(bdev->bd_inode);
+        device->dev_root = root->fs_info->dev_root;
+        device->bdev = bdev;
+
+        ret = btrfs_add_device(trans, root, device);
+        if (ret)
+                goto out_close_bdev;
+
+        total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
+        btrfs_set_super_total_bytes(&root->fs_info->super_copy,
+                                    total_bytes + device->total_bytes);
+
+        total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
+        btrfs_set_super_num_devices(&root->fs_info->super_copy,
+                                    total_bytes + 1);
+
+        list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
+        list_add(&device->dev_alloc_list,
+                 &root->fs_info->fs_devices->alloc_list);
+        root->fs_info->fs_devices->num_devices++;
+out:
+        btrfs_end_transaction(trans, root);
+        mutex_unlock(&root->fs_info->fs_mutex);
+        return ret;
+
+out_close_bdev:
+        close_bdev_excl(bdev);
+        goto out;
+}
+
 int btrfs_update_device(struct btrfs_trans_handle *trans,
                         struct btrfs_device *device)
 {
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 6fe8440b37a7..6f173450378b 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -133,4 +133,5 @@ int btrfs_grow_device(struct btrfs_trans_handle *trans,
 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
                                        u8 *uuid);
 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size);
+int btrfs_init_new_device(struct btrfs_root *root, char *path);
 #endif