On 05/25/2018 12:43 PM, Qu Wenruo wrote:
> Refactor btrfs_check_super_valid() by the ways:
>
> 1) Rename it to btrfs_validate_mount_super()
> Now it's more obvious when the function should be called.
>
> 2) Extract core check routine into __validate_super()
> So later write time check can reuse it, and if needed, we could also
> use __validate_super() to check each super block.
>
> 3) Add more comment about btrfs_validate_mount_super()
> Mostly of what it doesn't check and when it should be called.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Su Yue <suy.fnst@xxxxxxxxxxxxxx>
> ---
> fs/btrfs/disk-io.c | 29 +++++++++++++++++++++++++----
> 1 file changed, 25 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
> index 13c5f90995aa..b981ecc4b6f9 100644
> --- a/fs/btrfs/disk-io.c
> +++ b/fs/btrfs/disk-io.c
> @@ -2440,9 +2440,19 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
> return ret;
> }
>
> -static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info)
> +/*
> + * Real super block validation check
> + * NOTE: super csum type and incompat features will not be checked here.
> + *
> + * @sb: super block to check
> + * @mirror_num: the super block number to check its bytenr:
> + * 0 means the primary (1st) sb,
> + * 1 and 2 means 2nd and 3rd backup copy
> + * -1 means to skip bytenr check
> + */
> +static int __validate_super(struct btrfs_fs_info *fs_info,
> + struct btrfs_super_block *sb, int mirror_num)
> {
> - struct btrfs_super_block *sb = fs_info->super_copy;
> u64 nodesize = btrfs_super_nodesize(sb);
> u64 sectorsize = btrfs_super_sectorsize(sb);
> int ret = 0;
> @@ -2545,7 +2555,8 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info)
> ret = -EINVAL;
> }
>
> - if (btrfs_super_bytenr(sb) != BTRFS_SUPER_INFO_OFFSET) {
> + if (mirror_num >= 0 &&
> + btrfs_super_bytenr(sb) != btrfs_sb_offset(mirror_num)) {
> btrfs_err(fs_info, "super offset mismatch %llu != %u",
> btrfs_super_bytenr(sb), BTRFS_SUPER_INFO_OFFSET);
> ret = -EINVAL;
> @@ -2589,6 +2600,16 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info)
> return ret;
> }
>
> +/*
> + * Check the validation of super block at mount time.
> + * Some checks already done by early mount, like csum type and incompat flags
> + * will be skipped.
> + */
> +static int btrfs_validate_mount_super(struct btrfs_fs_info *fs_info)
> +{
> + return __validate_super(fs_info, fs_info->super_copy, 0);
> +}
> +
> int open_ctree(struct super_block *sb,
> struct btrfs_fs_devices *fs_devices,
> char *options)
> @@ -2814,7 +2835,7 @@ int open_ctree(struct super_block *sb,
>
> memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
>
> - ret = btrfs_check_super_valid(fs_info);
> + ret = btrfs_validate_mount_super(fs_info);
> if (ret) {
> btrfs_err(fs_info, "superblock contains fatal errors");
> err = -EINVAL;
>
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