mke2fs: allow metadata blocks to be at the beginning of the file system
Add the extended options packed_meta_blocks and journal_location_front
which causes mke2fs to place the metadata blocks at the beginning of
the file system.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index 30f7839..9c38e20 100644
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -280,6 +280,16 @@
file system feature is enabled this option controls whether there will
be 0, 1, or 2 backup superblocks created in the file system.
.TP
+.B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
+Place the allocation bitmaps and the inode table at the beginning of the
+disk. This option requires that the flex_bg file system feature to be
+enabled in order for it to have effect, and will also create the journal
+at the beginning of the file system. This option is useful for flash
+devices that use SLC flash at the beginning of the disk.
+It also maximizes the range of contiguous data blocks, which
+can be useful for certain specialized use cases, such as supported
+Shingled Drives.
+.TP
.BI root_owner [=uid:gid]
Specify the numeric user and group ID of the root directory. If no UID:GID
is specified, use the user and group ID of the user running \fBmke2fs\fR.
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 9e6169d..c3783ba 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -94,6 +94,7 @@
int journal_size;
int journal_flags;
static int lazy_itable_init;
+static int packed_meta_blocks;
static char *bad_blocks_filename = NULL;
static __u32 fs_stride;
static int quotatype = -1; /* Initialize both user and group quotas by default */
@@ -311,6 +312,40 @@
ext2fs_badblocks_list_iterate_end(bb_iter);
}
+static errcode_t packed_allocate_tables(ext2_filsys fs)
+{
+ errcode_t retval;
+ dgrp_t i;
+ blk64_t goal = 0;
+
+ for (i = 0; i < fs->group_desc_count; i++) {
+ retval = ext2fs_new_block2(fs, goal, NULL, &goal);
+ if (retval)
+ return retval;
+ ext2fs_block_alloc_stats2(fs, goal, +1);
+ ext2fs_block_bitmap_loc_set(fs, i, goal);
+ }
+ for (i = 0; i < fs->group_desc_count; i++) {
+ retval = ext2fs_new_block2(fs, goal, NULL, &goal);
+ if (retval)
+ return retval;
+ ext2fs_block_alloc_stats2(fs, goal, +1);
+ ext2fs_inode_bitmap_loc_set(fs, i, goal);
+ }
+ for (i = 0; i < fs->group_desc_count; i++) {
+ blk64_t end = ext2fs_blocks_count(fs->super) - 1;
+ retval = ext2fs_get_free_blocks2(fs, goal, end,
+ fs->inode_blocks_per_group,
+ fs->block_map, &goal);
+ if (retval)
+ return retval;
+ ext2fs_block_alloc_stats_range(fs, goal,
+ fs->inode_blocks_per_group, +1);
+ ext2fs_inode_table_loc_set(fs, i, goal);
+ }
+ return 0;
+}
+
static void write_inode_tables(ext2_filsys fs, int lazy_flag, int itable_zeroed)
{
errcode_t retval;
@@ -755,6 +790,13 @@
r_usage++;
continue;
}
+ } else if (strcmp(token, "packed_meta_blocks") == 0) {
+ if (arg)
+ packed_meta_blocks = strtoul(arg, &p, 0);
+ else
+ packed_meta_blocks = 1;
+ if (packed_meta_blocks)
+ journal_location = 0;
} else if (strcmp(token, "stride") == 0) {
if (!arg) {
r_usage++;
@@ -916,6 +958,7 @@
"\tstripe-width=<RAID stride * data disks in blocks>\n"
"\toffset=<offset to create the file system>\n"
"\tresize=<resize maximum size in blocks>\n"
+ "\tpacked_meta_blocks=<0 to disable, 1 to enable>\n"
"\tlazy_itable_init=<0 to disable, 1 to enable>\n"
"\tlazy_journal_init=<0 to disable, 1 to enable>\n"
"\troot_uid=<uid of root directory>\n"
@@ -2040,6 +2083,11 @@
fs_param.s_log_block_size);
free(journal_location_string);
+ packed_meta_blocks = get_bool_from_profile(fs_types,
+ "packed_meta_blocks", 0);
+ if (packed_meta_blocks)
+ journal_location = 0;
+
/* Get options from profile */
for (cpp = fs_types; *cpp; cpp++) {
tmp = NULL;
@@ -2635,7 +2683,11 @@
fs->stride = fs_stride = fs->super->s_raid_stride;
if (!quiet)
printf("%s", _("Allocating group tables: "));
- retval = ext2fs_allocate_tables(fs);
+ if ((fs->super->s_feature_incompat & EXT4_FEATURE_INCOMPAT_FLEX_BG) &&
+ packed_meta_blocks)
+ retval = packed_allocate_tables(fs);
+ else
+ retval = ext2fs_allocate_tables(fs);
if (retval) {
com_err(program_name, retval, "%s",
_("while trying to allocate filesystem tables"));
diff --git a/misc/mke2fs.conf.5.in b/misc/mke2fs.conf.5.in
index 894805a..f29e854 100644
--- a/misc/mke2fs.conf.5.in
+++ b/misc/mke2fs.conf.5.in
@@ -365,6 +365,10 @@
.B sparse_super2
feature enabled should be created with 0, 1, or 2 backup superblocks.
.TP
+.I packed_meta_blocks
+This boolean relation specifes whether the allocation bitmaps, inode
+table, and journal should be located at the beginning of the file system.
+.TP
.I inode_ratio
This relation specifies the default inode ratio if the user does not
specify one on the command line.