mke2fs: Deprecate -K option, introduce discard/nodiscard
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.
-K option is with this commit deprecated and should not be used anymore.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index b46e7e2..c587d81 100644
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -45,9 +45,6 @@
.I journal-options
]
[
-.B \-K
-]
-[
.B \-N
.I number-of-inodes
]
@@ -240,6 +237,17 @@
.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
+advertises that discard also zeroes data (any subsequent read after the discard
+and before write returns zero), then mark all not-yet-zeroed inode tables 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. This is the default.
.RE
.TP
.BI \-f " fragment-size"
@@ -369,10 +377,6 @@
@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 286f6ee..ec4a810 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -806,6 +806,10 @@
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;
@@ -821,7 +825,9 @@
"\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);
@@ -1301,6 +1307,10 @@
parse_journal_opts(optarg);
break;
case 'K':
+ fprintf(stderr, _("Warning: -K option is deprecated and "
+ "should not be used anymore. Use "
+ "\'-E nodiscard\' extended option "
+ "instead!\n"));
discard = 0;
break;
case 'j':