On 24.04.19 г. 17:47 ч., Johannes Thumshirn wrote:
> inspect-internal dump-superblock's load_and_dump_sb() already reads a
> super block from a file descriptor and places it into a 'struct
> btrfs_super_block'.
>
> For inspect-internal dump-csum we need this super block as well but don't
> care about printing it.
>
> Separate the read from the dump phase so we can re-use it elsewhere.
>
> Signed-off-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
> ---
> cmds-inspect-dump-super.c | 6 +++---
> utils.c | 17 +++++++++++++++++
> utils.h | 2 ++
> 3 files changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/cmds-inspect-dump-super.c b/cmds-inspect-dump-super.c
> index 7815c863f2ed..516760fad3da 100644
> --- a/cmds-inspect-dump-super.c
> +++ b/cmds-inspect-dump-super.c
> @@ -483,10 +483,10 @@ static int load_and_dump_sb(char *filename, int fd, u64 sb_bytenr, int full,
>
> sb = (struct btrfs_super_block *)super_block_data;
>
> - ret = pread64(fd, super_block_data, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
> - if (ret != BTRFS_SUPER_INFO_SIZE) {
> + ret = load_sb(fd, sb_bytenr, sb, BTRFS_SUPER_INFO_SIZE);
There is no point in passing BTRFS_SUPER_INFO_SIZE since you already
have a function, just hide this detail inside load_sb.
> + if (ret) {
> /* check if the disk if too short for further superblock */
> - if (ret == 0 && errno == 0)
> + if (ret == -ENOSPC)
> return 0;
>
> error("failed to read the superblock on %s at %llu",
> diff --git a/utils.c b/utils.c
> index 9e26c884cc6c..b15cfcf5a434 100644
> --- a/utils.c
> +++ b/utils.c
> @@ -2593,3 +2593,20 @@ void print_all_devices(struct list_head *devices)
> print_device_info(dev, "\t");
> printf("\n");
> }
> +
> +int load_sb(int fd, u64 bytenr, struct btrfs_super_block *sb, size_t size)
> +{
> + int ret;
> +
> + if (size != BTRFS_SUPER_INFO_SIZE)
> + return -EINVAL;
> +
> + ret = pread64(fd, sb, size, bytenr);
> + if (ret != size) {
> + if (ret == 0 && errno == 0)
> + return -ENOSPC;
Makes no sense to return -ENOSPC on read error. Perhahps EINVAL or some
such?
> +
> + return -errno;
> + }
> + return 0;
> +}
> diff --git a/utils.h b/utils.h
> index 7c5eb798557d..65549374b19c 100644
> --- a/utils.h
> +++ b/utils.h
> @@ -171,6 +171,8 @@ unsigned long total_memory(void);
> void print_device_info(struct btrfs_device *device, char *prefix);
> void print_all_devices(struct list_head *devices);
>
> +int load_sb(int fd, u64 bytenr, struct btrfs_super_block *sb, size_t size);
> +
> /*
> * Global program state, configurable by command line and available to
> * functions without extra context passing.
>
