Btrfs: add disk ioctl, mostly working

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

5 files changed, 221 insertions, 17 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c872a7e67abd..3ba4df20c913 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -16,6 +16,28 @@ struct dev_lookup {
         struct block_device *bdev;
 };
 
+int btrfs_insert_dev_radix(struct btrfs_root *root,
+                           struct block_device *bdev,
+                           u64 block_start,
+                           u64 num_blocks)
+{
+        struct dev_lookup *lookup;
+        char b[BDEVNAME_SIZE];
+        int ret;
+
+        lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
+        if (!lookup)
+                return -ENOMEM;
+        lookup->block_start = block_start;
+        lookup->num_blocks = num_blocks;
+        lookup->bdev = bdev;
+printk("inserting %s into dev radix %Lu %Lu\n", bdevname(bdev, b), block_start, num_blocks);
+
+        ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
+                                num_blocks - 1, lookup);
+        return ret;
+}
+
 u64 bh_blocknr(struct buffer_head *bh)
 {
         int blkbits = bh->b_page->mapping->host->i_blkbits;
@@ -34,6 +56,8 @@ static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
 {
         struct btrfs_node *node = btrfs_buffer_node(buf);
         if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
+                printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
+                       bh_blocknr(buf), btrfs_header_blocknr(&node->header));
                 BUG();
         }
         return 0;
@@ -76,11 +100,10 @@ out_unlock:
         return ret;
 }
 
-static int map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
+int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
                              u64 logical)
 {
         struct dev_lookup *lookup[2];
-        char b[BDEVNAME_SIZE];
 
         int ret;
 
@@ -96,7 +119,6 @@ static int map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
         }
         bh->b_bdev = lookup[0]->bdev;
         bh->b_blocknr = logical - lookup[0]->block_start;
-printk("logical mapping %Lu to %lu bdev  %s\n", logical, bh->b_blocknr, bdevname(bh->b_bdev, b));
         set_buffer_mapped(bh);
         ret = 0;
 out:
@@ -126,7 +148,7 @@ struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
         bh = head;
         do {
                 if (!buffer_mapped(bh)) {
-                        err = map_bh_to_logical(root, bh, first_block);
+                        err = btrfs_map_bh_to_logical(root, bh, first_block);
                         BUG_ON(err);
                 }
                 if (bh_blocknr(bh) == blocknr) {
@@ -150,7 +172,7 @@ static int btree_get_block(struct inode *inode, sector_t iblock,
 {
         int err;
         struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
-        err = map_bh_to_logical(root, bh, iblock);
+        err = btrfs_map_bh_to_logical(root, bh, iblock);
         return err;
 }
 
@@ -396,6 +418,89 @@ printk("all worked\n");
         return root;
 }
 
+int btrfs_open_disk(struct btrfs_root *root, u64 block_start, u64 num_blocks,
+                    char *filename, int name_len)
+{
+        char *null_filename;
+        struct block_device *bdev;
+        int ret;
+
+        if (block_start == 0) {
+printk("skipping disk with block_start == 0\n");
+return 0;
+        }
+        null_filename = kmalloc(name_len + 1, GFP_NOFS);
+        if (!null_filename)
+                return -ENOMEM;
+        memcpy(null_filename, filename, name_len);
+        null_filename[name_len] = '\0';
+
+        bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
+        if (IS_ERR(bdev)) {
+                ret = PTR_ERR(bdev);
+                goto out;
+        }
+        set_blocksize(bdev, root->fs_info->sb->s_blocksize);
+        ret = btrfs_insert_dev_radix(root, bdev, block_start, num_blocks);
+        BUG_ON(ret);
+        ret = 0;
+out:
+        kfree(null_filename);
+        return ret;
+}
+
+static int read_device_info(struct btrfs_root *root)
+{
+        struct btrfs_path *path;
+        int ret;
+        struct btrfs_key key;
+        struct btrfs_leaf *leaf;
+        struct btrfs_device_item *dev_item;
+        int nritems;
+        int slot;
+
+        root = root->fs_info->dev_root;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+        key.objectid = 0;
+        key.offset = 0;
+        key.flags = 0;
+        btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
+
+        mutex_lock(&root->fs_info->fs_mutex);
+        ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+        leaf = btrfs_buffer_leaf(path->nodes[0]);
+        nritems = btrfs_header_nritems(&leaf->header);
+        while(1) {
+                slot = path->slots[0];
+                if (slot >= nritems) {
+                        ret = btrfs_next_leaf(root, path);
+                        if (ret)
+                                break;
+                        leaf = btrfs_buffer_leaf(path->nodes[0]);
+                        nritems = btrfs_header_nritems(&leaf->header);
+                        slot = path->slots[0];
+                }
+                btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
+                if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
+                        path->slots[0]++;
+                        continue;
+                }
+                dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
+printk("found key %Lu %Lu\n", key.objectid, key.offset);
+                ret = btrfs_open_disk(root, key.objectid, key.offset,
+                                      (char *)(dev_item + 1),
+                                      btrfs_device_pathlen(dev_item));
+                BUG_ON(ret);
+                path->slots[0]++;
+        }
+        btrfs_free_path(path);
+        mutex_unlock(&root->fs_info->fs_mutex);
+        return 0;
+}
+
 struct btrfs_root *open_ctree(struct super_block *sb)
 {
         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
@@ -463,17 +568,26 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         if (!btrfs_super_root(disk_super))
                 return NULL;
 
+        i_size_write(fs_info->btree_inode,
+                     btrfs_super_total_blocks(disk_super) <<
+                     fs_info->btree_inode->i_blkbits);
+
         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
         ret = radix_tree_insert(&fs_info->dev_radix,
                                 dev_lookup->block_start +
-                                dev_lookup->num_blocks, dev_lookup);
+                                dev_lookup->num_blocks - 1, dev_lookup);
         BUG_ON(ret);
 
         fs_info->disk_super = disk_super;
+
         dev_root->node = read_tree_block(tree_root,
                                           btrfs_super_device_root(disk_super));
+
+        ret = read_device_info(dev_root);
+        BUG_ON(ret);
+
         tree_root->node = read_tree_block(tree_root,
                                           btrfs_super_root(disk_super));
         BUG_ON(!tree_root->node);
@@ -562,7 +676,7 @@ static int free_dev_radix(struct btrfs_fs_info *fs_info)
                                 close_bdev_excl(lookup[i]->bdev);
                         radix_tree_delete(&fs_info->dev_radix,
                                           lookup[i]->block_start +
-                                          lookup[i]->num_blocks);
+                                          lookup[i]->num_blocks - 1);
                         kfree(lookup[i]);
                 }
         }
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 46cc5dc9d572..aa9f56c38419 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -42,4 +42,10 @@ int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
                                       struct btrfs_key *location);
 u64 bh_blocknr(struct buffer_head *bh);
+int btrfs_insert_dev_radix(struct btrfs_root *root,
+                           struct block_device *bdev,
+                           u64 block_start,
+                           u64 num_blocks);
+int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
+                             u64 logical);
 #endif
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 201fb3270723..497fadd98c3a 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -10,4 +10,6 @@ struct btrfs_ioctl_vol_args {
 
 #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
                                    struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_ADD_DISK _IOW(BTRFS_IOCTL_MAGIC, 2, \
+                                   struct btrfs_ioctl_vol_args)
 #endif
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 4ff0cc1efb13..c46d7eafcf62 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1073,6 +1073,7 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
 
                 }
                 map_bh(result, inode->i_sb, blocknr);
+                btrfs_map_bh_to_logical(root, result, blocknr);
                 goto out;
         }
 
@@ -1092,7 +1093,8 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
         extent_end = extent_start + btrfs_file_extent_num_blocks(item);
         if (iblock >= extent_start && iblock < extent_end) {
                 err = 0;
-                map_bh(result, inode->i_sb, blocknr + iblock - extent_start);
+                btrfs_map_bh_to_logical(root, result, blocknr + iblock -
+                                        extent_start);
                 goto out;
         }
 allocate:
@@ -1112,6 +1114,7 @@ allocate:
         set_buffer_new(result);
         map_bh(result, inode->i_sb, blocknr);
 
+        btrfs_map_bh_to_logical(root, result, blocknr);
 out:
         btrfs_release_path(root, path);
         btrfs_free_path(path);
@@ -1153,12 +1156,6 @@ static int btrfs_readpage(struct file *file, struct page *page)
         return mpage_readpage(page, btrfs_get_block);
 }
 
-static int btrfs_readpages(struct file *file, struct address_space *mapping,
-                           struct list_head *pages, unsigned nr_pages)
-{
-        return mpage_readpages(mapping, pages, nr_pages, btrfs_get_block);
-}
-
 static int btrfs_writepage(struct page *page, struct writeback_control *wbc)
 {
         return nobh_writepage(page, btrfs_get_block, wbc);
@@ -1831,12 +1828,81 @@ printk("adding snapshot name %.*s root %Lu %Lu %u\n", namelen, name, key.objecti
         return 0;
 }
 
+static int add_disk(struct btrfs_root *root, char *name, int namelen)
+{
+        struct block_device *bdev;
+        struct btrfs_path *path;
+        struct super_block *sb = root->fs_info->sb;
+        struct btrfs_root *dev_root = root->fs_info->dev_root;
+        struct btrfs_trans_handle *trans;
+        struct btrfs_device_item *dev_item;
+        struct btrfs_key key;
+        u16 item_size;
+        u64 num_blocks;
+        u64 new_blocks;
+        int ret;
+printk("adding disk %s\n", name);
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+        num_blocks = btrfs_super_total_blocks(root->fs_info->disk_super);
+        bdev = open_bdev_excl(name, O_RDWR, sb);
+        if (IS_ERR(bdev)) {
+                ret = PTR_ERR(bdev);
+printk("open bdev excl failed ret %d\n", ret);
+                goto out_nolock;
+        }
+        set_blocksize(bdev, sb->s_blocksize);
+        new_blocks = bdev->bd_inode->i_size >> sb->s_blocksize_bits;
+        key.objectid = num_blocks;
+        key.offset = new_blocks;
+        key.flags = 0;
+        btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
+
+        mutex_lock(&dev_root->fs_info->fs_mutex);
+        trans = btrfs_start_transaction(dev_root, 1);
+        item_size = sizeof(*dev_item) + namelen;
+printk("insert empty on %Lu %Lu %u size %d\n", num_blocks, new_blocks, key.flags, item_size);
+        ret = btrfs_insert_empty_item(trans, dev_root, path, &key, item_size);
+        if (ret) {
+printk("insert failed %d\n", ret);
+                close_bdev_excl(bdev);
+                if (ret > 0)
+                        ret = -EEXIST;
+                goto out;
+        }
+        dev_item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]),
+                                  path->slots[0], struct btrfs_device_item);
+        btrfs_set_device_pathlen(dev_item, namelen);
+        memcpy(dev_item + 1, name, namelen);
+        mark_buffer_dirty(path->nodes[0]);
+
+        ret = btrfs_insert_dev_radix(root, bdev, num_blocks, new_blocks);
+
+        if (!ret) {
+                btrfs_set_super_total_blocks(root->fs_info->disk_super,
+                                             num_blocks + new_blocks);
+                i_size_write(root->fs_info->btree_inode,
+                             (num_blocks + new_blocks) <<
+                             root->fs_info->btree_inode->i_blkbits);
+        }
+
+out:
+        ret = btrfs_commit_transaction(trans, dev_root);
+        BUG_ON(ret);
+        mutex_unlock(&root->fs_info->fs_mutex);
+out_nolock:
+        btrfs_free_path(path);
+
+        return ret;
+}
+
 static int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
                        cmd, unsigned long arg)
 {
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_ioctl_vol_args vol_args;
-        int ret;
+        int ret = 0;
         int namelen;
         struct btrfs_path *path;
         u64 root_dirid;
@@ -1869,10 +1935,21 @@ static int btrfs_ioctl(struct inode *inode, struct file *filp, unsigned int
                         ret = create_snapshot(root, vol_args.name, namelen);
                 WARN_ON(ret);
                 break;
+        case BTRFS_IOC_ADD_DISK:
+                if (copy_from_user(&vol_args,
+                                   (struct btrfs_ioctl_vol_args __user *)arg,
+                                   sizeof(vol_args)))
+                        return -EFAULT;
+                namelen = strlen(vol_args.name);
+                if (namelen > BTRFS_VOL_NAME_MAX)
+                        return -EINVAL;
+                vol_args.name[namelen] = '\0';
+                ret = add_disk(root, vol_args.name, namelen);
+                break;
         default:
                 return -ENOTTY;
         }
-        return 0;
+        return ret;
 }
 
 static struct kmem_cache *btrfs_inode_cachep;
@@ -2004,7 +2081,6 @@ static struct file_operations btrfs_dir_file_operations = {
 
 static struct address_space_operations btrfs_aops = {
         .readpage       = btrfs_readpage,
-        .readpages      = btrfs_readpages,
         .writepage      = btrfs_writepage,
         .sync_page      = block_sync_page,
         .prepare_write  = btrfs_prepare_write,
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 3a15943ea8ed..8740752f3845 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -116,7 +116,13 @@ int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
         struct btrfs_fs_info *fs_info = root->fs_info;
         struct btrfs_root *tree_root = fs_info->tree_root;
         struct btrfs_root *extent_root = fs_info->extent_root;
+        struct btrfs_root *dev_root = fs_info->dev_root;
 
+        if (btrfs_super_device_root(fs_info->disk_super) !=
+            bh_blocknr(dev_root->node)) {
+                btrfs_set_super_device_root(fs_info->disk_super,
+                                            bh_blocknr(dev_root->node));
+        }
         while(1) {
                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
                 if (old_extent_block == bh_blocknr(extent_root->node))