Btrfs: Add support for online device removal
This required a few structural changes to the code that manages bdev pointers:
The VFS super block now gets an anon-bdev instead of a pointer to the
lowest bdev. This allows us to avoid swapping the super block bdev pointer
around at run time.
The code to read in the super block no longer goes through the extent
buffer interface. Things got ugly keeping the mapping constant.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fabc31b..9d5424a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -78,9 +78,13 @@
spin_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, len);
- spin_unlock(&em_tree->lock);
- if (em)
+ if (em) {
+ em->bdev =
+ BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
+ spin_unlock(&em_tree->lock);
goto out;
+ }
+ spin_unlock(&em_tree->lock);
em = alloc_extent_map(GFP_NOFS);
if (!em) {
@@ -90,7 +94,7 @@
em->start = 0;
em->len = (u64)-1;
em->block_start = 0;
- em->bdev = inode->i_sb->s_bdev;
+ em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
spin_lock(&em_tree->lock);
ret = add_extent_mapping(em_tree, em);
@@ -435,11 +439,6 @@
ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
BUG_ON(ret);
- if (offset == BTRFS_SUPER_INFO_OFFSET) {
- bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
- submit_bio(rw, bio);
- return 0;
- }
return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num);
}
@@ -587,8 +586,7 @@
list = &fs_info->fs_devices->devices;
list_for_each(next, list) {
device = list_entry(next, struct btrfs_device, dev_list);
- if (device->bdev && device->bdev != fs_info->sb->s_bdev)
- close_bdev_excl(device->bdev);
+ close_bdev_excl(device->bdev);
device->bdev = NULL;
}
return 0;
@@ -1118,6 +1116,7 @@
u32 leafsize;
u32 blocksize;
u32 stripesize;
+ struct buffer_head *bh;
struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
@@ -1153,7 +1152,6 @@
spin_lock_init(&fs_info->new_trans_lock);
init_completion(&fs_info->kobj_unregister);
- sb_set_blocksize(sb, BTRFS_SUPER_INFO_SIZE);
fs_info->tree_root = tree_root;
fs_info->extent_root = extent_root;
fs_info->chunk_root = chunk_root;
@@ -1170,6 +1168,9 @@
fs_info->btree_inode->i_ino = 1;
fs_info->btree_inode->i_nlink = 1;
+ sb->s_blocksize = 4096;
+ sb->s_blocksize_bits = blksize_bits(4096);
+
/*
* we set the i_size on the btree inode to the max possible int.
* the real end of the address space is determined by all of
@@ -1229,19 +1230,16 @@
__setup_root(4096, 4096, 4096, 4096, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
- fs_info->sb_buffer = read_tree_block(tree_root,
- BTRFS_SUPER_INFO_OFFSET,
- 4096);
- if (!fs_info->sb_buffer)
+ bh = __bread(fs_devices->latest_bdev,
+ BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
+ if (!bh)
goto fail_iput;
- read_extent_buffer(fs_info->sb_buffer, &fs_info->super_copy, 0,
- sizeof(fs_info->super_copy));
+ memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
+ brelse(bh);
- read_extent_buffer(fs_info->sb_buffer, fs_info->fsid,
- (unsigned long)btrfs_super_fsid(fs_info->sb_buffer),
- BTRFS_FSID_SIZE);
+ memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
disk_super = &fs_info->super_copy;
if (!btrfs_super_root(disk_super))
@@ -1263,7 +1261,9 @@
tree_root->leafsize = leafsize;
tree_root->sectorsize = sectorsize;
tree_root->stripesize = stripesize;
- sb_set_blocksize(sb, sectorsize);
+
+ sb->s_blocksize = sectorsize;
+ sb->s_blocksize_bits = blksize_bits(sectorsize);
if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
sizeof(disk_super->magic))) {
@@ -1339,7 +1339,6 @@
fail_sys_array:
mutex_unlock(&fs_info->fs_mutex);
fail_sb_buffer:
- free_extent_buffer(fs_info->sb_buffer);
extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
fail_iput:
iput(fs_info->btree_inode);
@@ -1380,41 +1379,44 @@
struct list_head *cur;
struct list_head *head = &root->fs_info->fs_devices->devices;
struct btrfs_device *dev;
- struct extent_buffer *sb;
+ struct btrfs_super_block *sb;
struct btrfs_dev_item *dev_item;
struct buffer_head *bh;
int ret;
int do_barriers;
int max_errors;
int total_errors = 0;
+ u32 crc;
+ u64 flags;
max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
do_barriers = !btrfs_test_opt(root, NOBARRIER);
- sb = root->fs_info->sb_buffer;
- dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
- dev_item);
+ sb = &root->fs_info->super_for_commit;
+ dev_item = &sb->dev_item;
list_for_each(cur, head) {
dev = list_entry(cur, struct btrfs_device, dev_list);
- btrfs_set_device_type(sb, dev_item, dev->type);
- btrfs_set_device_id(sb, dev_item, dev->devid);
- btrfs_set_device_total_bytes(sb, dev_item, dev->total_bytes);
- btrfs_set_device_bytes_used(sb, dev_item, dev->bytes_used);
- btrfs_set_device_io_align(sb, dev_item, dev->io_align);
- btrfs_set_device_io_width(sb, dev_item, dev->io_width);
- btrfs_set_device_sector_size(sb, dev_item, dev->sector_size);
- write_extent_buffer(sb, dev->uuid,
- (unsigned long)btrfs_device_uuid(dev_item),
- BTRFS_UUID_SIZE);
+ btrfs_set_stack_device_type(dev_item, dev->type);
+ btrfs_set_stack_device_id(dev_item, dev->devid);
+ btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
+ btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
+ btrfs_set_stack_device_io_align(dev_item, dev->io_align);
+ btrfs_set_stack_device_io_width(dev_item, dev->io_width);
+ btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
+ memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
+ flags = btrfs_super_flags(sb);
+ btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
- btrfs_set_header_flag(sb, BTRFS_HEADER_FLAG_WRITTEN);
- csum_tree_block(root, sb, 0);
- bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET /
- root->fs_info->sb->s_blocksize,
+ crc = ~(u32)0;
+ crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
+ BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
+ btrfs_csum_final(crc, sb->csum);
+
+ bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
BTRFS_SUPER_INFO_SIZE);
- read_extent_buffer(sb, bh->b_data, 0, BTRFS_SUPER_INFO_SIZE);
+ memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
dev->pending_io = bh;
get_bh(bh);
@@ -1483,15 +1485,6 @@
int ret;
ret = write_all_supers(root);
-#if 0
- if (!btrfs_test_opt(root, NOBARRIER))
- blkdev_issue_flush(sb->s_bdev, NULL);
- set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, super);
- ret = sync_page_range_nolock(btree_inode, btree_inode->i_mapping,
- super->start, super->len);
- if (!btrfs_test_opt(root, NOBARRIER))
- blkdev_issue_flush(sb->s_bdev, NULL);
-#endif
return ret;
}
@@ -1570,8 +1563,6 @@
if (root->fs_info->dev_root->node);
free_extent_buffer(root->fs_info->dev_root->node);
- free_extent_buffer(fs_info->sb_buffer);
-
btrfs_free_block_groups(root->fs_info);
del_fs_roots(fs_info);
@@ -1652,7 +1643,7 @@
{
struct backing_dev_info *bdi;
- bdi = root->fs_info->sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
+ bdi = &root->fs_info->bdi;
if (root->fs_info->throttles && bdi_write_congested(bdi)) {
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
congestion_wait(WRITE, HZ/20);