Btrfs: Support for online FS resize (grow and shrink)

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

fs/btrfs/ctree.h

@@ -508,6 +508,8 @@ BTRFS_SETGET_STACK_FUNCS(block_group_used, struct btrfs_block_group_item,
 			 used, 64);
 BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
 			 used, 64);
+BTRFS_SETGET_FUNCS(disk_block_group_flags, struct btrfs_block_group_item,
+		   flags, 8);
 
 /* struct btrfs_inode_ref */
 BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
@@ -960,6 +962,9 @@ struct extent_buffer *__btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
 					     int level,
 					     u64 hint,
 					     u64 empty_size);
+int btrfs_grow_extent_tree(struct btrfs_trans_handle *trans,
+			   struct btrfs_root *root, u64 new_size);
+int btrfs_shrink_extent_tree(struct btrfs_root *root, u64 new_size);
 int btrfs_insert_extent_backref(struct btrfs_trans_handle *trans,
 				 struct btrfs_root *root,
 				 struct btrfs_path *path, u64 bytenr,
@@ -1117,6 +1122,9 @@ int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, struct btrfs_path *path,
 			u64 isize);
 /* inode.c */
+unsigned long btrfs_force_ra(struct address_space *mapping,
+			      struct file_ra_state *ra, struct file *file,
+			      pgoff_t offset, pgoff_t last_index);
 int btrfs_check_free_space(struct btrfs_root *root, u64 num_required,
 			   int for_del);
 int btrfs_page_mkwrite(struct vm_area_struct *vma, struct page *page);
@@ -1162,4 +1170,6 @@ void btrfs_sysfs_del_super(struct btrfs_fs_info *root);
 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
 int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
 			struct btrfs_root *root, struct inode *inode);
+/* super.c */
+u64 btrfs_parse_size(char *str);
 #endif

fs/btrfs/disk-io.c

@@ -471,13 +471,17 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
 	return root;
 }
 
-struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
-				      struct btrfs_key *location,
-				      const char *name, int namelen)
+struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
+					      struct btrfs_key *location)
 {
 	struct btrfs_root *root;
 	int ret;
 
+	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
+		return fs_info->tree_root;
+	if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
+		return fs_info->extent_root;
+
 	root = radix_tree_lookup(&fs_info->fs_roots_radix,
 				 (unsigned long)location->objectid);
 	if (root)
@@ -494,6 +498,23 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 		kfree(root);
 		return ERR_PTR(ret);
 	}
+	ret = btrfs_find_dead_roots(fs_info->tree_root,
+				    root->root_key.objectid, root);
+	BUG_ON(ret);
+
+	return root;
+}
+
+struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
+				      struct btrfs_key *location,
+				      const char *name, int namelen)
+{
+	struct btrfs_root *root;
+	int ret;
+
+	root = btrfs_read_fs_root_no_name(fs_info, location);
+	if (!root)
+		return NULL;
 
 	ret = btrfs_set_root_name(root, name, namelen);
 	if (ret) {
@@ -509,11 +530,6 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 		kfree(root);
 		return ERR_PTR(ret);
 	}
-
-	ret = btrfs_find_dead_roots(fs_info->tree_root,
-				    root->root_key.objectid, root);
-	BUG_ON(ret);
-
 	return root;
 }
 #if 0

fs/btrfs/disk-io.h

@@ -39,6 +39,8 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 				      const char *name, int namelen);
 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
 					       struct btrfs_key *location);
+struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
+					      struct btrfs_key *location);
 int btrfs_insert_dev_radix(struct btrfs_root *root,
 			   struct block_device *bdev,
 			   u64 device_id,

fs/btrfs/inode.c

@@ -2346,7 +2346,7 @@ static int create_snapshot(struct btrfs_root *root, char *name, int namelen)
 	return ret;
 }
 
-static unsigned long force_ra(struct address_space *mapping,
+unsigned long btrfs_force_ra(struct address_space *mapping,
 			      struct file_ra_state *ra, struct file *file,
 			      pgoff_t offset, pgoff_t last_index)
 {
@@ -2372,6 +2372,8 @@ int btrfs_defrag_file(struct file *file) {
 	unsigned long ra_index = 0;
 	u64 page_start;
 	u64 page_end;
+	u64 delalloc_start;
+	u64 existing_delalloc;
 	unsigned long i;
 	int ret;
 
@@ -2385,7 +2387,8 @@ int btrfs_defrag_file(struct file *file) {
 	last_index = inode->i_size >> PAGE_CACHE_SHIFT;
 	for (i = 0; i <= last_index; i++) {
 		if (i == ra_index) {
-			ra_index = force_ra(inode->i_mapping, &file->f_ra,
+			ra_index = btrfs_force_ra(inode->i_mapping,
+						  &file->f_ra,
 						  file, ra_index, last_index);
 		}
 		page = grab_cache_page(inode->i_mapping, i);
@@ -2404,8 +2407,19 @@ int btrfs_defrag_file(struct file *file) {
 		page_end = page_start + PAGE_CACHE_SIZE - 1;
 
 		lock_extent(em_tree, page_start, page_end, GFP_NOFS);
+		delalloc_start = page_start;
+		existing_delalloc =
+			count_range_bits(&BTRFS_I(inode)->extent_tree,
+					 &delalloc_start, page_end,
+					 PAGE_CACHE_SIZE, EXTENT_DELALLOC);
 		set_extent_delalloc(em_tree, page_start,
 				    page_end, GFP_NOFS);
+
+		spin_lock(&root->fs_info->delalloc_lock);
+		root->fs_info->delalloc_bytes += PAGE_CACHE_SIZE -
+						 existing_delalloc;
+		spin_unlock(&root->fs_info->delalloc_lock);
+
 		unlock_extent(em_tree, page_start, page_end, GFP_NOFS);
 		set_page_dirty(page);
 		unlock_page(page);
@@ -2418,6 +2432,89 @@ int btrfs_defrag_file(struct file *file) {
 	return 0;
 }
 
+static int btrfs_ioctl_resize(struct btrfs_root *root, void __user *arg)
+{
+	u64 new_size;
+	u64 old_size;
+	struct btrfs_ioctl_vol_args *vol_args;
+	struct btrfs_trans_handle *trans;
+	char *sizestr;
+	int ret = 0;
+	int namelen;
+	int mod = 0;
+
+	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;
+	}
+	namelen = strlen(vol_args->name);
+	if (namelen > BTRFS_VOL_NAME_MAX) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	sizestr = vol_args->name;
+	if (!strcmp(sizestr, "max"))
+		new_size = root->fs_info->sb->s_bdev->bd_inode->i_size;
+	else {
+		if (sizestr[0] == '-') {
+			mod = -1;
+			sizestr++;
+		} else if (sizestr[0] == '+') {
+			mod = 1;
+			sizestr++;
+		}
+		new_size = btrfs_parse_size(sizestr);
+		if (new_size == 0) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	mutex_lock(&root->fs_info->fs_mutex);
+	old_size = btrfs_super_total_bytes(&root->fs_info->super_copy);
+
+	if (mod < 0) {
+		if (new_size > old_size) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+		new_size = old_size - new_size;
+	} else if (mod > 0) {
+		new_size = old_size + new_size;
+	}
+
+	if (new_size < 256 * 1024 * 1024) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+	if (new_size > root->fs_info->sb->s_bdev->bd_inode->i_size) {
+		ret = -EFBIG;
+		goto out_unlock;
+	}
+	new_size = (new_size / root->sectorsize) * root->sectorsize;
+
+printk("new size is %Lu\n", new_size);
+	if (new_size > old_size) {
+		trans = btrfs_start_transaction(root, 1);
+		ret = btrfs_grow_extent_tree(trans, root, new_size);
+		btrfs_commit_transaction(trans, root);
+	} else {
+		ret = btrfs_shrink_extent_tree(root, new_size);
+	}
+
+out_unlock:
+	mutex_unlock(&root->fs_info->fs_mutex);
+out:
+	kfree(vol_args);
+	return ret;
+}
+
 static int btrfs_ioctl_snap_create(struct btrfs_root *root, void __user *arg)
 {
 	struct btrfs_ioctl_vol_args *vol_args;
@@ -2510,6 +2607,8 @@ long btrfs_ioctl(struct file *file, unsigned int
 		return btrfs_ioctl_snap_create(root, (void __user *)arg);
 	case BTRFS_IOC_DEFRAG:
 		return btrfs_ioctl_defrag(file);
+	case BTRFS_IOC_RESIZE:
+		return btrfs_ioctl_resize(root, (void __user *)arg);
 	}
 
 	return -ENOTTY;

fs/btrfs/ioctl.h

@@ -30,4 +30,6 @@ struct btrfs_ioctl_vol_args {
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
 				   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_RESIZE _IOW(BTRFS_IOCTL_MAGIC, 3, \
+				   struct btrfs_ioctl_vol_args)
 #endif

fs/btrfs/root-tree.c

@@ -179,6 +179,11 @@ int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 	ret = btrfs_search_slot(trans, root, key, path, -1, 1);
 	if (ret < 0)
 		goto out;
+	if (ret) {
+btrfs_print_leaf(root, path->nodes[0]);
+printk("failed to del %Lu %u %Lu\n", key->objectid, key->type, key->offset);
+
+	}
 	BUG_ON(ret != 0);
 	leaf = path->nodes[0];
 	ri = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_item);

fs/btrfs/super.c

@@ -74,9 +74,9 @@ static match_table_t tokens = {
 	{Opt_err, NULL}
 };
 
-static unsigned long parse_size(char *str)
+u64 btrfs_parse_size(char *str)
 {
-	unsigned long res;
+	u64 res;
 	int mult = 1;
 	char *end;
 	char last;
@@ -150,7 +150,8 @@ static int parse_options (char * options,
 			if (info) {
 				char *num = match_strdup(&args[0]);
 				if (num) {
-					info->max_extent = parse_size(num);
+					info->max_extent =
+						btrfs_parse_size(num);
 					kfree(num);
 
 					info->max_extent = max_t(u64,