> diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> index 68d6bd18..9dd0e79c 100644
> --- a/mkfs/xfs_mkfs.c
> +++ b/mkfs/xfs_mkfs.c
> @@ -859,6 +859,7 @@ struct cli_params {
> int64_t logagno;
> int loginternal;
> int lsunit;
> + int is_supported;
>
> /* parameters where 0 is not a valid value */
> int64_t agcount;
> @@ -2496,6 +2497,68 @@ _("illegal CoW extent size hint %lld, must be less than %u.\n"),
> }
> }
>
> +/* Complain if this filesystem is not a supported configuration. */
> +static void
> +validate_supported(
> + struct xfs_mount *mp,
> + struct cli_params *cli)
> +{
> + /* Undocumented option to enable unsupported tiny filesystems. */
> + if (!cli->is_supported) {
> + printf(
> + _("Filesystems formatted with --unsupported are not supported!!\n"));
> + return;
> + }
> +
> + /*
> + * fstests has a large number of tests that create tiny filesystems to
> + * perform specific regression and resource depletion tests in a
> + * controlled environment. Avoid breaking fstests by allowing
> + * unsupported configurations if TEST_DIR, TEST_DEV, and QA_CHECK_FS
> + * are all set.
> + */
> + if (getenv("TEST_DIR") && getenv("TEST_DEV") && getenv("QA_CHECK_FS"))
> + return;
> +
> + /*
> + * We don't support filesystems smaller than 300MB anymore. Tiny
> + * filesystems have never been XFS' design target. This limit has been
> + * carefully calculated to prevent formatting with a log smaller than
> + * the "realistic" size.
> + *
> + * If the realistic log size is 64MB, there are four AGs, and the log
> + * AG should be at least 1/8 free after formatting, this gives us:
> + *
> + * 64MB * (8 / 7) * 4 = 293MB
> + */
> + if (mp->m_sb.sb_dblocks < MEGABYTES(300, mp->m_sb.sb_blocklog)) {
> + fprintf(stderr,
> + _("Filesystem must be larger than 300MB.\n"));
> + usage();
> + }
> +
> + /*
> + * For best performance, we don't allow unrealistically small logs.
> + * See the comment for XFS_MIN_REALISTIC_LOG_BLOCKS.
> + */
> + if (mp->m_sb.sb_logblocks <
> + XFS_MIN_REALISTIC_LOG_BLOCKS(mp->m_sb.sb_blocklog)) {
> + fprintf(stderr,
> + _("Log size must be at least 64MB.\n"));
> + usage();
> + }
> +
> + /*
> + * Filesystems should not have fewer than two AGs, because we need to
> + * have redundant superblocks.
> + */
> + if (mp->m_sb.sb_agcount < 2) {
> + fprintf(stderr,
> + _("Filesystem must have at least 2 superblocks for redundancy!\n"));
> + usage();
> + }
> +}
> +
> /*
> * Validate the configured stripe geometry, or is none is specified, pull
> * the configuration from the underlying device.
> @@ -3966,9 +4029,21 @@ main(
> struct cli_params cli = {
> .xi = &xi,
> .loginternal = 1,
> + .is_supported = 1,
> };
> struct mkfs_params cfg = {};
>
> + struct option long_options[] = {
> + {
> + .name = "unsupported",
> + .has_arg = no_argument,
> + .flag = &cli.is_supported,
> + .val = 0,
> + },
> + {NULL, 0, NULL, 0 },
> + };
> + int option_index = 0;
> +
> /* build time defaults */
> struct mkfs_default_params dft = {
> .source = _("package build definitions"),
> @@ -4028,8 +4103,11 @@ main(
> memcpy(&cli.sb_feat, &dft.sb_feat, sizeof(cli.sb_feat));
> memcpy(&cli.fsx, &dft.fsx, sizeof(cli.fsx));
>
> - while ((c = getopt(argc, argv, "b:c:d:i:l:L:m:n:KNp:qr:s:CfV")) != EOF) {
> + while ((c = getopt_long(argc, argv, "b:c:d:i:l:L:m:n:KNp:qr:s:CfV",
> + long_options, &option_index)) != EOF) {
> switch (c) {
> + case 0:
> + break;
> case 'C':
> case 'f':
> force_overwrite = 1;
> @@ -4167,6 +4245,8 @@ main(
> validate_extsize_hint(mp, &cli);
> validate_cowextsize_hint(mp, &cli);
>
> + validate_supported(mp, &cli);
> +
> /* Print the intended geometry of the fs. */
> if (!quiet || dry_run) {
> struct xfs_fsop_geom geo;
>
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
--
Carlos Maiolino
