Commit 0940ebf6 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

Btrfs: save balance parameters to disk 



Introduce a new btree objectid for storing balance item.  The reason is
to be able to resume restriper after a crash with the same parameters.
Balance item has a very high objectid and goes into tree of tree roots.

The key for the new item is as follows:

	[ BTRFS_BALANCE_OBJECTID ; BTRFS_BALANCE_ITEM_KEY ; 0 ]

Older kernels simply ignore it so it's safe to mount with an older
kernel and then go back to the newer one.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent cfa4c961

fs/btrfs/ctree.h

+132 −1
Original line number Diff line number Diff line
@@ -86,6 +86,9 @@ struct btrfs_ordered_sum; 
/* holds checksums of all the data extents */

#define BTRFS_CSUM_TREE_OBJECTID 7ULL



/* for storing balance parameters in the root tree */

#define BTRFS_BALANCE_OBJECTID -4ULL



/* orhpan objectid for tracking unlinked/truncated files */

#define BTRFS_ORPHAN_OBJECTID -5ULL
@@ -692,6 +695,54 @@ struct btrfs_root_ref { 
	__le16 name_len;

} __attribute__ ((__packed__));



struct btrfs_disk_balance_args {

	/*

	 * profiles to operate on, single is denoted by

	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE

	 */

	__le64 profiles;



	/* usage filter */

	__le64 usage;



	/* devid filter */

	__le64 devid;



	/* devid subset filter [pstart..pend) */

	__le64 pstart;

	__le64 pend;



	/* btrfs virtual address space subset filter [vstart..vend) */

	__le64 vstart;

	__le64 vend;



	/*

	 * profile to convert to, single is denoted by

	 * BTRFS_AVAIL_ALLOC_BIT_SINGLE

	 */

	__le64 target;



	/* BTRFS_BALANCE_ARGS_* */

	__le64 flags;



	__le64 unused[8];

} __attribute__ ((__packed__));



/*

 * store balance parameters to disk so that balance can be properly

 * resumed after crash or unmount

 */

struct btrfs_balance_item {

	/* BTRFS_BALANCE_* */

	__le64 flags;



	struct btrfs_disk_balance_args data;

	struct btrfs_disk_balance_args meta;

	struct btrfs_disk_balance_args sys;



	__le64 unused[4];

} __attribute__ ((__packed__));



#define BTRFS_FILE_EXTENT_INLINE 0

#define BTRFS_FILE_EXTENT_REG 1

#define BTRFS_FILE_EXTENT_PREALLOC 2
@@ -1409,6 +1460,8 @@ struct btrfs_ioctl_defrag_range_args { 
#define BTRFS_DEV_ITEM_KEY	216

#define BTRFS_CHUNK_ITEM_KEY	228



#define BTRFS_BALANCE_ITEM_KEY	248



/*

 * string items are for debugging.  They just store a short string of

 * data in the FS
@@ -2103,8 +2156,86 @@ BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup, 
BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,

		   num_devices, 64);



/* struct btrfs_super_block */

/* struct btrfs_balance_item */

BTRFS_SETGET_FUNCS(balance_flags, struct btrfs_balance_item, flags, 64);



static inline void btrfs_balance_data(struct extent_buffer *eb,

				      struct btrfs_balance_item *bi,

				      struct btrfs_disk_balance_args *ba)

{

	read_eb_member(eb, bi, struct btrfs_balance_item, data, ba);

}



static inline void btrfs_set_balance_data(struct extent_buffer *eb,

					  struct btrfs_balance_item *bi,

					  struct btrfs_disk_balance_args *ba)

{

	write_eb_member(eb, bi, struct btrfs_balance_item, data, ba);

}



static inline void btrfs_balance_meta(struct extent_buffer *eb,

				      struct btrfs_balance_item *bi,

				      struct btrfs_disk_balance_args *ba)

{

	read_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);

}



static inline void btrfs_set_balance_meta(struct extent_buffer *eb,

					  struct btrfs_balance_item *bi,

					  struct btrfs_disk_balance_args *ba)

{

	write_eb_member(eb, bi, struct btrfs_balance_item, meta, ba);

}



static inline void btrfs_balance_sys(struct extent_buffer *eb,

				     struct btrfs_balance_item *bi,

				     struct btrfs_disk_balance_args *ba)

{

	read_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);

}



static inline void btrfs_set_balance_sys(struct extent_buffer *eb,

					 struct btrfs_balance_item *bi,

					 struct btrfs_disk_balance_args *ba)

{

	write_eb_member(eb, bi, struct btrfs_balance_item, sys, ba);

}



static inline void

btrfs_disk_balance_args_to_cpu(struct btrfs_balance_args *cpu,

			       struct btrfs_disk_balance_args *disk)

{

	memset(cpu, 0, sizeof(*cpu));



	cpu->profiles = le64_to_cpu(disk->profiles);

	cpu->usage = le64_to_cpu(disk->usage);

	cpu->devid = le64_to_cpu(disk->devid);

	cpu->pstart = le64_to_cpu(disk->pstart);

	cpu->pend = le64_to_cpu(disk->pend);

	cpu->vstart = le64_to_cpu(disk->vstart);

	cpu->vend = le64_to_cpu(disk->vend);

	cpu->target = le64_to_cpu(disk->target);

	cpu->flags = le64_to_cpu(disk->flags);

}



static inline void

btrfs_cpu_balance_args_to_disk(struct btrfs_disk_balance_args *disk,

			       struct btrfs_balance_args *cpu)

{

	memset(disk, 0, sizeof(*disk));



	disk->profiles = cpu_to_le64(cpu->profiles);

	disk->usage = cpu_to_le64(cpu->usage);

	disk->devid = cpu_to_le64(cpu->devid);

	disk->pstart = cpu_to_le64(cpu->pstart);

	disk->pend = cpu_to_le64(cpu->pend);

	disk->vstart = cpu_to_le64(cpu->vstart);

	disk->vend = cpu_to_le64(cpu->vend);

	disk->target = cpu_to_le64(cpu->target);

	disk->flags = cpu_to_le64(cpu->flags);

}



/* struct btrfs_super_block */

BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);

BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);

BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,

fs/btrfs/volumes.c

+99 −0
Original line number Diff line number Diff line
@@ -2073,6 +2073,97 @@ error: 
	return ret;

}



static int insert_balance_item(struct btrfs_root *root,

			       struct btrfs_balance_control *bctl)

{

	struct btrfs_trans_handle *trans;

	struct btrfs_balance_item *item;

	struct btrfs_disk_balance_args disk_bargs;

	struct btrfs_path *path;

	struct extent_buffer *leaf;

	struct btrfs_key key;

	int ret, err;



	path = btrfs_alloc_path();

	if (!path)

		return -ENOMEM;



	trans = btrfs_start_transaction(root, 0);

	if (IS_ERR(trans)) {

		btrfs_free_path(path);

		return PTR_ERR(trans);

	}



	key.objectid = BTRFS_BALANCE_OBJECTID;

	key.type = BTRFS_BALANCE_ITEM_KEY;

	key.offset = 0;



	ret = btrfs_insert_empty_item(trans, root, path, &key,

				      sizeof(*item));

	if (ret)

		goto out;



	leaf = path->nodes[0];

	item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);



	memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));



	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);

	btrfs_set_balance_data(leaf, item, &disk_bargs);

	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);

	btrfs_set_balance_meta(leaf, item, &disk_bargs);

	btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);

	btrfs_set_balance_sys(leaf, item, &disk_bargs);



	btrfs_set_balance_flags(leaf, item, bctl->flags);



	btrfs_mark_buffer_dirty(leaf);

out:

	btrfs_free_path(path);

	err = btrfs_commit_transaction(trans, root);

	if (err && !ret)

		ret = err;

	return ret;

}



static int del_balance_item(struct btrfs_root *root)

{

	struct btrfs_trans_handle *trans;

	struct btrfs_path *path;

	struct btrfs_key key;

	int ret, err;



	path = btrfs_alloc_path();

	if (!path)

		return -ENOMEM;



	trans = btrfs_start_transaction(root, 0);

	if (IS_ERR(trans)) {

		btrfs_free_path(path);

		return PTR_ERR(trans);

	}



	key.objectid = BTRFS_BALANCE_OBJECTID;

	key.type = BTRFS_BALANCE_ITEM_KEY;

	key.offset = 0;



	ret = btrfs_search_slot(trans, root, &key, path, -1, 1);

	if (ret < 0)

		goto out;

	if (ret > 0) {

		ret = -ENOENT;

		goto out;

	}



	ret = btrfs_del_item(trans, root, path);

out:

	btrfs_free_path(path);

	err = btrfs_commit_transaction(trans, root);

	if (err && !ret)

		ret = err;

	return ret;

}



/*

 * Should be called with both balance and volume mutexes held to

 * serialize other volume operations (add_dev/rm_dev/resize) with
@@ -2423,7 +2514,11 @@ error: 


static void __cancel_balance(struct btrfs_fs_info *fs_info)

{

	int ret;



	unset_balance_control(fs_info);

	ret = del_balance_item(fs_info->tree_root);

	BUG_ON(ret);

}



void update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
@@ -2530,6 +2625,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl, 
	}



do_balance:

	ret = insert_balance_item(fs_info->tree_root, bctl);

	if (ret)

		goto out;



	set_balance_control(bctl);



	mutex_unlock(&fs_info->balance_mutex);

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