Btrfs: Fix super block updates during transaction commit
The super block written during commit was not consistent with the state of
the trees. This change adds an in-memory copy of the super so that we can
make sure to write out consistent data during a commit.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index fb6fffb..1998f86 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -306,6 +306,7 @@
u64 generation;
struct btrfs_transaction *running_transaction;
struct btrfs_super_block *disk_super;
+ struct btrfs_super_block super_copy;
struct buffer_head *sb_buffer;
struct super_block *sb;
struct inode *btree_inode;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d7615e1..7081729 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -471,6 +471,8 @@
if (!fs_info->sb_buffer)
goto fail_iput;
disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
+ fs_info->disk_super = disk_super;
+ memcpy(&fs_info->super_copy, disk_super, sizeof(fs_info->super_copy));
if (!btrfs_super_root(disk_super))
goto fail_sb_buffer;
@@ -479,7 +481,6 @@
btrfs_super_total_blocks(disk_super) <<
fs_info->btree_inode->i_blkbits);
- fs_info->disk_super = disk_super;
if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
sizeof(disk_super->magic))) {
@@ -527,8 +528,6 @@
int ret;
struct buffer_head *bh = root->fs_info->sb_buffer;
- btrfs_set_super_root(root->fs_info->disk_super,
- bh_blocknr(root->fs_info->tree_root->node));
lock_buffer(bh);
WARN_ON(atomic_read(&bh->b_count) < 1);
clear_buffer_dirty(bh);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8025e9f..7e55034 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -796,8 +796,8 @@
for (i = 0; i < extent_root->fs_info->extent_tree_insert_nr; i++) {
ins.objectid = extent_root->fs_info->extent_tree_insert[i];
- super_blocks_used = btrfs_super_blocks_used(info->disk_super);
- btrfs_set_super_blocks_used(info->disk_super,
+ super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
+ btrfs_set_super_blocks_used(&info->super_copy,
super_blocks_used + 1);
ret = btrfs_insert_item(trans, extent_root, &ins, &extent_item,
sizeof(extent_item));
@@ -892,8 +892,8 @@
BUG_ON(ret);
}
- super_blocks_used = btrfs_super_blocks_used(info->disk_super);
- btrfs_set_super_blocks_used(info->disk_super,
+ super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
+ btrfs_set_super_blocks_used(&info->super_copy,
super_blocks_used - num_blocks);
ret = btrfs_del_item(trans, extent_root, path);
if (ret) {
@@ -1032,7 +1032,7 @@
info->extent_tree_prealloc_nr = 0;
}
if (search_end == (u64)-1)
- search_end = btrfs_super_total_blocks(info->disk_super);
+ search_end = btrfs_super_total_blocks(&info->super_copy);
if (hint_block) {
block_group = btrfs_lookup_block_group(info, hint_block);
block_group = btrfs_find_block_group(root, block_group,
@@ -1361,8 +1361,8 @@
}
}
- super_blocks_used = btrfs_super_blocks_used(info->disk_super);
- btrfs_set_super_blocks_used(info->disk_super, super_blocks_used +
+ super_blocks_used = btrfs_super_blocks_used(&info->super_copy);
+ btrfs_set_super_blocks_used(&info->super_copy, super_blocks_used +
num_blocks);
ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
sizeof(extent_item));
@@ -1737,7 +1737,7 @@
BTRFS_BLOCK_GROUP_AVAIL);
}
if (key.objectid >=
- btrfs_super_total_blocks(info->disk_super))
+ btrfs_super_total_blocks(&info->super_copy))
break;
}
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index c11ecf5..2e797d5 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -144,7 +144,7 @@
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct btrfs_root *root = btrfs_sb(dentry->d_sb);
- struct btrfs_super_block *disk_super = root->fs_info->disk_super;
+ struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
buf->f_namelen = BTRFS_NAME_LEN;
buf->f_blocks = btrfs_super_total_blocks(disk_super);
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index a5a63d4..3b2face 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -380,6 +380,12 @@
else
prev_trans->use_count++;
}
+ btrfs_set_super_generation(&root->fs_info->super_copy,
+ cur_trans->transid);
+ btrfs_set_super_root(&root->fs_info->super_copy,
+ bh_blocknr(root->fs_info->tree_root->node));
+ memcpy(root->fs_info->disk_super, &root->fs_info->super_copy,
+ sizeof(root->fs_info->super_copy));
mutex_unlock(&root->fs_info->trans_mutex);
mutex_unlock(&root->fs_info->fs_mutex);
ret = btrfs_write_and_wait_transaction(trans, root);
@@ -389,8 +395,6 @@
put_transaction(prev_trans);
mutex_unlock(&root->fs_info->trans_mutex);
}
- btrfs_set_super_generation(root->fs_info->disk_super,
- cur_trans->transid);
BUG_ON(ret);
write_ctree_super(trans, root);