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Btrfs: superblock duplication

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This patch implements superblock duplication. Superblocks
are stored at offset 16K, 64M and 256G on every devices.
Spaces used by superblocks are preserved by the allocator,
which uses a reverse mapping function to find the logical
addresses that correspond to superblocks. Thank you,

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
This commit is contained in:
Yan Zheng
2008-12-08 16:46:26 -05:00
committed by Chris Mason
parent d20f7043fa
commit a512bbf855
8 changed files with 279 additions and 119 deletions
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107
fs/btrfs/volumes.c
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@@ -423,15 +423,11 @@ int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
}
set_blocksize(bdev, 4096);
bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
bh = btrfs_read_dev_super(bdev);
if (!bh)
goto error_close;
disk_super = (struct btrfs_super_block *)bh->b_data;
if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
sizeof(disk_super->magic)))
goto error_brelse;
devid = le64_to_cpu(disk_super->dev_item.devid);
if (devid != device->devid)
goto error_brelse;
@@ -529,17 +525,12 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
ret = set_blocksize(bdev, 4096);
if (ret)
goto error_close;
bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
bh = btrfs_read_dev_super(bdev);
if (!bh) {
ret = -EIO;
goto error_close;
}
disk_super = (struct btrfs_super_block *)bh->b_data;
if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
sizeof(disk_super->magic))) {
ret = -EINVAL;
goto error_brelse;
}
devid = le64_to_cpu(disk_super->dev_item.devid);
transid = btrfs_super_generation(disk_super);
if (disk_super->label[0])
@@ -553,7 +544,6 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
printk("devid %Lu transid %Lu %s\n", devid, transid, path);
ret = device_list_add(path, disk_super, devid, fs_devices_ret);
error_brelse:
brelse(bh);
error_close:
close_bdev_exclusive(bdev, flags);
@@ -1016,17 +1006,12 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
}
set_blocksize(bdev, 4096);
bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
bh = btrfs_read_dev_super(bdev);
if (!bh) {
ret = -EIO;
goto error_close;
}
disk_super = (struct btrfs_super_block *)bh->b_data;
if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
sizeof(disk_super->magic))) {
ret = -ENOENT;
goto error_brelse;
}
devid = le64_to_cpu(disk_super->dev_item.devid);
dev_uuid = disk_super->dev_item.uuid;
device = btrfs_find_device(root, devid, dev_uuid,
@@ -2563,6 +2548,88 @@ int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
mirror_num, NULL);
}
int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
u64 chunk_start, u64 physical, u64 devid,
u64 **logical, int *naddrs, int *stripe_len)
{
struct extent_map_tree *em_tree = &map_tree->map_tree;
struct extent_map *em;
struct map_lookup *map;
u64 *buf;
u64 bytenr;
u64 length;
u64 stripe_nr;
int i, j, nr = 0;
spin_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, chunk_start, 1);
spin_unlock(&em_tree->lock);
BUG_ON(!em || em->start != chunk_start);
map = (struct map_lookup *)em->bdev;
length = em->len;
if (map->type & BTRFS_BLOCK_GROUP_RAID10)
do_div(length, map->num_stripes / map->sub_stripes);
else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
do_div(length, map->num_stripes);
buf = kzalloc(sizeof(u64) * map->num_stripes, GFP_NOFS);
BUG_ON(!buf);
for (i = 0; i < map->num_stripes; i++) {
if (devid && map->stripes[i].dev->devid != devid)
continue;
if (map->stripes[i].physical > physical ||
map->stripes[i].physical + length <= physical)
continue;
stripe_nr = physical - map->stripes[i].physical;
do_div(stripe_nr, map->stripe_len);
if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
stripe_nr = stripe_nr * map->num_stripes + i;
do_div(stripe_nr, map->sub_stripes);
} else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
stripe_nr = stripe_nr * map->num_stripes + i;
}
bytenr = chunk_start + stripe_nr * map->stripe_len;
for (j = 0; j < nr; j++) {
if (buf[j] == bytenr)
break;
}
if (j == nr)
buf[nr++] = bytenr;
}
for (i = 0; i > nr; i++) {
struct btrfs_multi_bio *multi;
struct btrfs_bio_stripe *stripe;
int ret;
length = 1;
ret = btrfs_map_block(map_tree, WRITE, buf[i],
&length, &multi, 0);
BUG_ON(ret);
stripe = multi->stripes;
for (j = 0; j < multi->num_stripes; j++) {
if (stripe->physical >= physical &&
physical < stripe->physical + length)
break;
}
BUG_ON(j >= multi->num_stripes);
kfree(multi);
}
*logical = buf;
*naddrs = nr;
*stripe_len = map->stripe_len;
free_extent_map(em);
return 0;
}
int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
u64 logical, struct page *page)
{
@@ -3003,7 +3070,7 @@ int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
return read_one_dev(root, buf, dev_item);
}
int btrfs_read_sys_array(struct btrfs_root *root)
int btrfs_read_sys_array(struct btrfs_root *root, u64 sb_bytenr)
{
struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
struct extent_buffer *sb;
@@ -3018,7 +3085,7 @@ int btrfs_read_sys_array(struct btrfs_root *root)
u32 cur;
struct btrfs_key key;
sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
sb = btrfs_find_create_tree_block(root, sb_bytenr,
BTRFS_SUPER_INFO_SIZE);
if (!sb)
return -ENOMEM;