From: Jose R. Santos <jrs@xxxxxxxxxx>
New bitmap and inode table allocation for FLEX_BG
Change the way we allocate bitmaps and inode tables if the FLEX_BG
feature is used at mke2fs time. It places calculates a new offset for
bitmaps and inode table base on the number of groups that the user
wishes to pack together using the new "-G" option. Creating a
filesystem with 64 block groups in a flex group can be done by:
mke2fs -j -I 256 -O flex_bg -G 32 /dev/sdX
Signed-off-by: Jose R. Santos <jrs@xxxxxxxxxx>
Signed-off-by: Valerie Clement <valerie.clement@xxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
--
lib/ext2fs/alloc_tables.c | 110 ++++++++++++++++++++++++++++++++++++++++++++-
lib/ext2fs/ext2_fs.h | 5 ++
lib/ext2fs/initialize.c | 9 +++-
misc/mke2fs.8.in | 15 ++++++
misc/mke2fs.c | 51 +++++++++++++++++++--
5 files changed, 181 insertions(+), 9 deletions(-)
diff --git a/lib/ext2fs/alloc_tables.c b/lib/ext2fs/alloc_tables.c
index 9b4f0e5..c9f5e59 100644
--- a/lib/ext2fs/alloc_tables.c
+++ b/lib/ext2fs/alloc_tables.c
@@ -27,18 +27,79 @@
#include "ext2_fs.h"
#include "ext2fs.h"
+/*
+ * This routine searches for free blocks that can allocate a full
+ * group of bitmaps or inode tables for a flexbg group. Returns the
+ * block number with a correct offset were the bitmaps and inode
+ * tables can be allocated continously and in order.
+ */
+static blk_t flexbg_offset(ext2_filsys fs, dgrp_t group, blk_t start_blk,
+ ext2fs_block_bitmap bmap, int offset, int size)
+{
+ int flexbg, flexbg_size, elem_size;
+ blk_t last_blk, first_free = 0;
+ dgrp_t last_grp;
+
+ flexbg_size = 1 << fs->super->s_log_groups_per_flex;
+ flexbg = group / flexbg_size;
+
+ if (size > fs->super->s_blocks_per_group / 8)
+ size = fs->super->s_blocks_per_group / 8;
+
+ /*
+ * Dont do a long search if the previous block
+ * search is still valid.
+ */
+ if (start_blk && group % flexbg_size) {
+ if (size > flexbg_size)
+ elem_size = fs->inode_blocks_per_group;
+ else
+ elem_size = 1;
+ if (ext2fs_test_block_bitmap_range(bmap, start_blk + elem_size,
+ size))
+ return start_blk + elem_size;
+ }
+
+ start_blk = ext2fs_group_first_block(fs, flexbg_size * flexbg);
+ last_grp = group | (flexbg_size - 1);
+ if (last_grp > fs->group_desc_count)
+ last_grp = fs->group_desc_count;
+ last_blk = ext2fs_group_last_block(fs, last_grp);
+
+ /* Find the first available block */
+ if (ext2fs_get_free_blocks(fs, start_blk, last_blk, 1, bmap,
+ &first_free))
+ return first_free;
+
+ if (ext2fs_get_free_blocks(fs, first_free + offset, last_blk, size,
+ bmap, &first_free))
+ return first_free;
+
+ return first_free;
+}
+
errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
ext2fs_block_bitmap bmap)
{
errcode_t retval;
blk_t group_blk, start_blk, last_blk, new_blk, blk;
- int j;
+ dgrp_t last_grp;
+ int j, rem_grps, flexbg_size = 0;
group_blk = ext2fs_group_first_block(fs, group);
last_blk = ext2fs_group_last_block(fs, group);
if (!bmap)
bmap = fs->block_map;
+
+ if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+ flexbg_size = 1 << fs->super->s_log_groups_per_flex;
+ last_grp = group | (flexbg_size - 1);
+ rem_grps = last_grp - group;
+ if (last_grp > fs->group_desc_count)
+ last_grp = fs->group_desc_count;
+ }
/*
* Allocate the block and inode bitmaps, if necessary
@@ -56,6 +117,15 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
} else
start_blk = group_blk;
+ if (flexbg_size) {
+ int prev_block = 0;
+ if (group && fs->group_desc[group-1].bg_block_bitmap)
+ prev_block = fs->group_desc[group-1].bg_block_bitmap;
+ start_blk = flexbg_offset(fs, group, prev_block, bmap,
+ 0, rem_grps);
+ last_blk = ext2fs_group_last_block(fs, last_grp);
+ }
+
if (!fs->group_desc[group].bg_block_bitmap) {
retval = ext2fs_get_free_blocks(fs, start_blk, last_blk,
1, bmap, &new_blk);
@@ -66,6 +136,20 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
return retval;
ext2fs_mark_block_bitmap(bmap, new_blk);
fs->group_desc[group].bg_block_bitmap = new_blk;
+ if (flexbg_size) {
+ dgrp_t tmp = ext2fs_group_of_blk(fs, new_blk);
+ fs->group_desc[tmp].bg_free_blocks_count--;
+ fs->super->s_free_blocks_count--;
+ }
+ }
+
+ if (flexbg_size) {
+ int prev_block = 0;
+ if (group && fs->group_desc[group-1].bg_inode_bitmap)
+ prev_block = fs->group_desc[group-1].bg_inode_bitmap;
+ start_blk = flexbg_offset(fs, group, prev_block, bmap,
+ flexbg_size, rem_grps);
+ last_blk = ext2fs_group_last_block(fs, last_grp);
}
if (!fs->group_desc[group].bg_inode_bitmap) {
@@ -78,11 +162,27 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
return retval;
ext2fs_mark_block_bitmap(bmap, new_blk);
fs->group_desc[group].bg_inode_bitmap = new_blk;
+ if (flexbg_size) {
+ dgrp_t tmp = ext2fs_group_of_blk(fs, new_blk);
+ fs->group_desc[tmp].bg_free_blocks_count--;
+ fs->super->s_free_blocks_count--;
+ }
}
/*
* Allocate the inode table
*/
+ if (flexbg_size) {
+ int prev_block = 0;
+ if (group && fs->group_desc[group-1].bg_inode_table)
+ prev_block = fs->group_desc[group-1].bg_inode_table;
+ group_blk = flexbg_offset(fs, group, prev_block, bmap,
+ flexbg_size * 2,
+ fs->inode_blocks_per_group *
+ rem_grps);
+ last_blk = ext2fs_group_last_block(fs, last_grp);
+ }
+
if (!fs->group_desc[group].bg_inode_table) {
retval = ext2fs_get_free_blocks(fs, group_blk, last_blk,
fs->inode_blocks_per_group,
@@ -91,8 +191,14 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
return retval;
for (j=0, blk = new_blk;
j < fs->inode_blocks_per_group;
- j++, blk++)
+ j++, blk++) {
ext2fs_mark_block_bitmap(bmap, blk);
+ if (flexbg_size) {
+ dgrp_t tmp = ext2fs_group_of_blk(fs, blk);
+ fs->group_desc[tmp].bg_free_blocks_count--;
+ fs->super->s_free_blocks_count--;
+ }
+ }
fs->group_desc[group].bg_inode_table = new_blk;
}
ext2fs_group_desc_csum_set(fs, group);
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 444211d..d4731f8 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -563,7 +563,10 @@ struct ext2_super_block {
__u16 s_mmp_interval; /* # seconds to wait in MMP checking */
__u64 s_mmp_block; /* Block for multi-mount protection */
__u32 s_raid_stripe_width; /* blocks on all data disks (N*stride)*/
- __u32 s_reserved[163]; /* Padding to the end of the block */
+ __u8 s_log_groups_per_flex; /* FLEX_BG group size */
+ __u8 s_reserved_char_pad;
+ __u16 s_reserved_pad; /* Padding to next 32bits */
+ __u32 s_reserved[162]; /* Padding to the end of the block */
};
/*
diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c
index c2e00e8..68cfbd8 100644
--- a/lib/ext2fs/initialize.c
+++ b/lib/ext2fs/initialize.c
@@ -158,6 +158,7 @@ errcode_t ext2fs_initialize(const char *name, int flags,
set_field(s_first_meta_bg, 0);
set_field(s_raid_stride, 0); /* default stride size: 0 */
set_field(s_raid_stripe_width, 0); /* default stripe width: 0 */
+ set_field(s_log_groups_per_flex, 0);
set_field(s_flags, 0);
if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
retval = EXT2_ET_UNSUPP_FEATURE;
@@ -366,12 +367,16 @@ ipg_retry:
* group, and fill in the correct group statistics for group.
* Note that although the block bitmap, inode bitmap, and
* inode table have not been allocated (and in fact won't be
- * by this routine), they are accounted for nevertheless.
+ * by this routine), they are accounted for nevertheless. If
+ * FLEX_BG meta-data grouping is used, only account for the
+ * superblock and group descriptors (the inode tables and
+ * bitmaps will be accounted for when allocated).
*/
super->s_free_blocks_count = 0;
for (i = 0; i < fs->group_desc_count; i++) {
numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
-
+ if (fs->super->s_log_groups_per_flex)
+ numblocks += 2 + fs->inode_blocks_per_group;
super->s_free_blocks_count += numblocks;
fs->group_desc[i].bg_free_blocks_count = numblocks;
fs->group_desc[i].bg_free_inodes_count =
diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index a32c34a..9cc3895 100644
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -26,6 +26,10 @@ mke2fs \- create an ext2/ext3 filesystem
.I blocks-per-group
]
[
+.B \-G
+.I number-of-groups
+]
+[
.B \-i
.I bytes-per-inode
]
@@ -232,6 +236,12 @@ option rather than manipulating the number of blocks per group.)
This option is generally used by developers who
are developing test cases.
.TP
+.BI \-G " number-of-groups"
+Specify the number of block goups that will be packed together to
+create one large virtual block group on an ext4 filesystem. This
+improves meta-data locality and performance on meta-data heavy
+workloads. The number of goups must be a power of 2.
+.TP
.BI \-i " bytes-per-inode"
Specify the bytes/inode ratio.
.B mke2fs
@@ -425,6 +435,11 @@ Use hashed b-trees to speed up lookups in large directories.
.B filetype
Store file type information in directory entries.
.TP
+.B flex_bg
+Allow bitmaps and inode tables for a block group to be placed anywhere
+on the storage media (use with -G option to group meta-data in order
+to create a large virtual block group).
+.TP
.B has_journal
Create an ext3 journal (as if using the
.TP
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 3fd2e5d..7787341 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -98,8 +98,9 @@ static void usage(void)
fprintf(stderr, _("Usage: %s [-c|-l filename] [-b block-size] "
"[-f fragment-size]\n\t[-i bytes-per-inode] [-I inode-size] "
"[-J journal-options]\n"
- "\t[-N number-of-inodes] [-m reserved-blocks-percentage] "
- "[-o creator-os]\n\t[-g blocks-per-group] [-L volume-label] "
+ "\t[-G meta group size] [-N number-of-inodes]\n"
+ "\t[-m reserved-blocks-percentage] [-o creator-os]\n"
+ "\t[-g blocks-per-group] [-L volume-label] "
"[-M last-mounted-directory]\n\t[-O feature[,...]] "
"[-r fs-revision] [-E extended-option[,...]]\n"
"\t[-T fs-type] [-jnqvFSV] device [blocks-count]\n"),
@@ -448,6 +449,30 @@ static void write_inode_tables(ext2_filsys fs)
progress_close(&progress);
}
+static blk64_t expected_free_block_count(ext2_filsys fs, dgrp_t group)
+{
+ blk64_t tmp;
+ blk64_t blks;
+
+ blks = ext2fs_super_and_bgd_loc(fs, group, 0, 0, 0, 0);
+
+ if (EXT2_HAS_INCOMPAT_FEATURE(fs->super,
+ EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
+ tmp = fs->group_desc[group].bg_block_bitmap;
+ if (group != ext2fs_group_of_blk(fs, tmp))
+ blks++;
+
+ tmp = fs->group_desc[group].bg_inode_bitmap;
+ if (group != ext2fs_group_of_blk(fs, tmp))
+ blks++;
+
+ tmp = fs->group_desc[group].bg_inode_table;
+ if (group != ext2fs_group_of_blk(fs, tmp))
+ blks += fs->inode_blocks_per_group;
+ }
+ return blks;
+}
+
static void setup_lazy_bg(ext2_filsys fs)
{
dgrp_t i;
@@ -481,7 +506,7 @@ static void setup_lazy_bg(ext2_filsys fs)
i == fs->group_desc_count - 1)
continue;
- blks = ext2fs_super_and_bgd_loc(fs, i, 0, 0, 0, 0);
+ blks = expected_free_block_count(fs, i);
if (bg->bg_free_blocks_count == blks &&
bg->bg_flags & EXT2_BG_INODE_UNINIT) {
bg->bg_flags |= EXT2_BG_BLOCK_UNINIT;
@@ -1151,6 +1176,7 @@ static void PRS(int argc, char *argv[])
int blocksize = 0;
int inode_ratio = 0;
int inode_size = 0;
+ unsigned long flex_bg_size = 0;
double reserved_ratio = 5.0;
int sector_size = 0;
int show_version_only = 0;
@@ -1234,7 +1260,7 @@ static void PRS(int argc, char *argv[])
}
while ((c = getopt (argc, argv,
- "b:cf:g:i:jl:m:no:qr:s:tvE:FI:J:L:M:N:O:R:ST:V")) != EOF) {
+ "b:cf:g:G:i:jl:m:no:qr:s:tvE:FI:J:L:M:N:O:R:ST:V")) != EOF) {
switch (c) {
case 'b':
blocksize = strtol(optarg, &tmp, 0);
@@ -1285,6 +1311,20 @@ static void PRS(int argc, char *argv[])
exit(1);
}
break;
+ case 'G':
+ flex_bg_size = strtoul(optarg, &tmp, 0);
+ if (*tmp) {
+ com_err(program_name, 0,
+ _("Illegal number for Flex_BG size"));
+ exit(1);
+ }
+ if (flex_bg_size < 2 ||
+ (flex_bg_size & (flex_bg_size-1)) != 0) {
+ com_err(program_name, 0,
+ _("Flex_BG size must be a power of 2"));
+ exit(1);
+ }
+ break;
case 'i':
inode_ratio = strtoul(optarg, &tmp, 0);
if (inode_ratio < EXT2_MIN_BLOCK_SIZE ||
@@ -1685,6 +1725,9 @@ static void PRS(int argc, char *argv[])
}
}
+ if (flex_bg_size)
+ fs_param.s_log_groups_per_flex = int_log2(flex_bg_size);
+
if (inode_size == 0) {
inode_size = get_int_from_profile(fs_types, "inode_size", 0);
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
