Before this patchset, if we want to use backup roots, it's only possible to let btrfs-check to automatically choose the backup.
If user want to use a specified backup, it can only use -r|--tree-root option along with backup roots dump from "btrfs ins dump-super". This patchset will introduce optional argument for -b|--backup, so user can specify which backup to use by providing the generation difference (-3, -2, -1). If the optional argument is not provided, the default value is -1, and the behavior should be pretty much the same. Qu Wenruo (3): btrfs-progs: utils-lib: Use error() to replace fprintf(stderr, "ERROR: ") btrfs-progs: disk-io: Handle backup root more correctly btrfs-progs: check: Introduce optional argument for -b|--backup Documentation/btrfs-check.asciidoc | 6 ++-- check/main.c | 33 +++++++++++++++--- common/utils.h | 1 + ctree.h | 8 +++++ disk-io.c | 55 ++++++++++++++++++++++++------ disk-io.h | 33 +++++++++++------- utils-lib.c | 25 +++++++++++--- 7 files changed, 127 insertions(+), 34 deletions(-) -- 2.23.0