On Tue, Oct 10, 2017 at 07:51:11AM +0000, Qu Wenruo wrote:
> Introduce --fix-dev-size option to fix device related problems.
Please don't add it to 'check', this is not the right place for the
targeted fixes. -> 'btrfs rescue'
> This repairing is also included in --repair, but considering the safety
> and potential affected users, it's better to provide a option to fix and
> only fix device size related problem to avoid full --repair.
>
> Reported-by: Asif Youssuff <yoasif@xxxxxxxxx>
> Reported-by: Rich Rauenzahn <rrauenza@xxxxxxxxx>
> Signed-off-by: Qu Wenruo <quwenruo.btrfs@xxxxxxx>
> ---
> Documentation/btrfs-check.asciidoc | 23 +++++++++++++++++++++++
> cmds-check.c | 28 +++++++++++++++++++++++++++-
> 2 files changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/btrfs-check.asciidoc b/Documentation/btrfs-check.asciidoc
> index fbf48847ac25..e45c7a457bac 100644
> --- a/Documentation/btrfs-check.asciidoc
> +++ b/Documentation/btrfs-check.asciidoc
> @@ -93,6 +93,29 @@ the entire free space cache. This option with 'v2' provides an alternative
> method of clearing the free space cache that doesn't require mounting the
> filesystem.
>
> +--fix-dev-size::
> +From v4.14-rc kernels, a more restrict device size checker is introduced, while
> +old kernel doesn't strictly align its device size, so it may cause noisy kernel
> +warning for newer kernel, like:
> ++
> +....
> +WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs]
> +....
> ++
> +And for some case where super block total device size may mismatch with all
> +devices, and the filesystem will be unable to be mounted, with kernel message
> +like:
> ++
> +....
> +BTRFS error (device sdb): super_total_bytes 92017859088384 mismatch with fs_devices total_rw_bytes 92017859094528
> +....
> ++
> +This option will fix both problems by aligning all size of devices, and
> +re-calculating superblock total bytes.
> ++
> +Although such repairing is included in *--repair* option, considering the
> +safety of *--repair*, this option is provided to suppress all other dangerous
> +repairing and only fix device sizes related problems.
>
> DANGEROUS OPTIONS
> -----------------
> diff --git a/cmds-check.c b/cmds-check.c
> index 007781fa5d1b..fdb6d832eee1 100644
> --- a/cmds-check.c
> +++ b/cmds-check.c
> @@ -11746,6 +11746,8 @@ out:
> return err;
> }
>
> +static int reset_devs_size(struct btrfs_fs_info *fs_info);
> +
> static int do_check_chunks_and_extents(struct btrfs_fs_info *fs_info)
> {
> int ret;
> @@ -11756,6 +11758,12 @@ static int do_check_chunks_and_extents(struct btrfs_fs_info *fs_info)
> ret = check_chunks_and_extents_v2(fs_info);
> else
> ret = check_chunks_and_extents(fs_info);
> + /* Also repair device sizes if needed */
> + if (repair && !ret) {
> + ret = reset_devs_size(fs_info);
> + if (ret > 0)
> + ret = 0;
> + }
>
> return ret;
> }
> @@ -13088,6 +13096,8 @@ const char * const cmd_check_usage[] = {
> "-b|--backup use the first valid backup root copy",
> "--force skip mount checks, repair is not possible",
> "--repair try to repair the filesystem",
> + "--fix-dev-size repair device size related problem",
> + " will not trigger other repair",
> "--readonly run in read-only mode (default)",
> "--init-csum-tree create a new CRC tree",
> "--init-extent-tree create a new extent tree",
> @@ -13128,6 +13138,7 @@ int cmd_check(int argc, char **argv)
> int qgroups_repaired = 0;
> unsigned ctree_flags = OPEN_CTREE_EXCLUSIVE;
> int force = 0;
> + bool fix_dev_size = false;
>
> while(1) {
> int c;
> @@ -13135,7 +13146,7 @@ int cmd_check(int argc, char **argv)
> GETOPT_VAL_INIT_EXTENT, GETOPT_VAL_CHECK_CSUM,
> GETOPT_VAL_READONLY, GETOPT_VAL_CHUNK_TREE,
> GETOPT_VAL_MODE, GETOPT_VAL_CLEAR_SPACE_CACHE,
> - GETOPT_VAL_FORCE };
> + GETOPT_VAL_FORCE, GETOPT_VAL_FIX_DEV_SIZE };
> static const struct option long_options[] = {
> { "super", required_argument, NULL, 's' },
> { "repair", no_argument, NULL, GETOPT_VAL_REPAIR },
> @@ -13158,6 +13169,8 @@ int cmd_check(int argc, char **argv)
> { "clear-space-cache", required_argument, NULL,
> GETOPT_VAL_CLEAR_SPACE_CACHE},
> { "force", no_argument, NULL, GETOPT_VAL_FORCE },
> + { "fix-dev-size", no_argument, NULL,
> + GETOPT_VAL_FIX_DEV_SIZE },
> { NULL, 0, NULL, 0}
> };
>
> @@ -13245,6 +13258,11 @@ int cmd_check(int argc, char **argv)
> case GETOPT_VAL_FORCE:
> force = 1;
> break;
> + case GETOPT_VAL_FIX_DEV_SIZE:
> + fix_dev_size = true;
> + repair = 1;
> + ctree_flags |= OPEN_CTREE_WRITES;
> + break;
> }
> }
>
> @@ -13371,6 +13389,14 @@ int cmd_check(int argc, char **argv)
> report_qgroups(1);
> goto close_out;
> }
> +
> + if (fix_dev_size) {
> + ret = reset_devs_size(info);
> + if (ret > 0)
> + ret = 0;
> + err |= !!ret;
> + goto close_out;
> + }
> if (subvolid) {
> printf("Print extent state for subvolume %llu on %s\nUUID: %s\n",
> subvolid, argv[optind], uuidbuf);
> --
> 2.14.2
>
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