Commit 2d69a0f8 authored by Yan Zheng's avatar Yan Zheng Committed by Chris Mason
Browse files

Btrfs: avoid potential super block corruption 



The data in fs_info->super_for_commit are zeros before the
first transaction commit. If tree log sync and system crash
both occur before the first transaction commit, super block
will get corrupted.

This fixes it by properly filling in the super_for_commit field at
open time.

Signed-off-by: default avatarYan Zheng <zheng.yan@oracle.com>
parent dd3fd8bd

fs/btrfs/disk-io.c

+3 −1
Original line number Diff line number Diff line
@@ -1609,6 +1609,8 @@ struct btrfs_root *open_ctree(struct super_block *sb, 
		goto fail_iput;



	memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));

	memcpy(&fs_info->super_for_commit, &fs_info->super_copy,

	       sizeof(fs_info->super_for_commit));

	brelse(bh);



	memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
@@ -1790,7 +1792,7 @@ struct btrfs_root *open_ctree(struct super_block *sb, 


	btrfs_read_block_groups(extent_root);



	fs_info->generation = generation + 1;

	fs_info->generation = generation;

	fs_info->last_trans_committed = generation;

	fs_info->data_alloc_profile = (u64)-1;

	fs_info->metadata_alloc_profile = (u64)-1;

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