Lukas Czerner wrote:
> It would be nice to have consistent "discard" options in every system
> tool (mount, fsck, mkfs) taking advantage of discards. Also "discard"
> and "nodiscard" is more descriptive instead of just "-K" and can be
> easily defaulted and it is something we can not do with "-K".
>
> With this commit you need to specify extended option like this:
>
> ./mke2fs -T <fstype> -E nodiscard <device>
>
> in order make a filesystem without discarding the device first. And
>
> ./mke2fs -T <fstype> -E discard <device>
>
> respectively.
Sadly, we probably need to map -K onto -E nodiscard and deprecate
it for now, rather than just removing it altogether?
-Eric
> Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> ---
> misc/mke2fs.8.in | 18 +++++++++++-------
> misc/mke2fs.c | 13 ++++++++-----
> 2 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
> index b46e7e2..6b437bc 100644
> --- a/misc/mke2fs.8.in
> +++ b/misc/mke2fs.8.in
> @@ -45,9 +45,6 @@ mke2fs \- create an ext2/ext3/ext4 filesystem
> .I journal-options
> ]
> [
> -.B \-K
> -]
> -[
> .B \-N
> .I number-of-inodes
> ]
> @@ -240,6 +237,17 @@ enable lazy inode table initialization.
> .B test_fs
> Set a flag in the filesystem superblock indicating that it may be
> mounted using experimental kernel code, such as the ext4dev filesystem.
> +.TP
> +.BI discard
> +Attempt to discard blocks at mkfs time (discarding blocks initially is useful
> +on solid state devices and sparse / thin-provisioned storage). When the device
> +advertise that discard also zeroes data (any subsequent read after the discard
> +and before write returns zero), then mark all not-yet-zeroed inode table as
> +zeroed. This significantly speeds up filesystem initialization. This is set
> +as default.
> +.TP
> +.BI nodiscard
> +Do not attempt to discard blocks at mkfs time.
> .RE
> .TP
> .BI \-f " fragment-size"
> @@ -369,10 +377,6 @@ and may be no more than 102,400 filesystem blocks.
> @JDEV@.BR size " or " device
> @JDEV@options can be given for a filesystem.
> .TP
> -.BI \-K
> -Keep, do not attempt to discard blocks at mkfs time (discarding blocks initially
> -is useful on solid state devices and sparse / thin-provisioned storage).
> -.TP
> .BI \-l " filename"
> Read the bad blocks list from
> .IR filename .
> diff --git a/misc/mke2fs.c b/misc/mke2fs.c
> index 0980045..32e3a2b 100644
> --- a/misc/mke2fs.c
> +++ b/misc/mke2fs.c
> @@ -753,6 +753,10 @@ static void parse_extended_opts(struct ext2_super_block *param,
> lazy_itable_init = strtoul(arg, &p, 0);
> else
> lazy_itable_init = 1;
> + } else if (!strcmp(token, "discard")) {
> + discard = 1;
> + } else if (!strcmp(token, "nodiscard")) {
> + discard = 0;
> } else {
> r_usage++;
> badopt = token;
> @@ -768,7 +772,9 @@ static void parse_extended_opts(struct ext2_super_block *param,
> "\tstripe-width=<RAID stride * data disks in blocks>\n"
> "\tresize=<resize maximum size in blocks>\n"
> "\tlazy_itable_init=<0 to disable, 1 to enable>\n"
> - "\ttest_fs\n\n"),
> + "\ttest_fs\n"
> + "\tdiscard\n"
> + "\tnodiscard\n\n"),
> badopt ? badopt : "");
> free(buf);
> exit(1);
> @@ -1168,7 +1174,7 @@ static void PRS(int argc, char *argv[])
> }
>
> while ((c = getopt (argc, argv,
> - "b:cf:g:G:i:jl:m:no:qr:s:t:vE:FI:J:KL:M:N:O:R:ST:U:V")) != EOF) {
> + "b:cf:g:G:i:jl:m:no:qr:s:t:vE:FI:J:L:M:N:O:R:ST:U:V")) != EOF) {
> switch (c) {
> case 'b':
> blocksize = strtol(optarg, &tmp, 0);
> @@ -1247,9 +1253,6 @@ static void PRS(int argc, char *argv[])
> case 'J':
> parse_journal_opts(optarg);
> break;
> - case 'K':
> - discard = 0;
> - break;
> case 'j':
> if (!journal_size)
> journal_size = -1;
--
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