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Date: 24 Nov 2006 17:48:31 +0100
From: Valerie Clement <Valerie.Clement@...l.net>
To: linux-ext4@...r.kernel.org
Subject: [RFC][PATCH 2/4] BIG_BG: larger block bitmaps
This patch modifies the read_block_bitmap() and the block allocation functions to take into account that the block bitmap can be stored on several consecutive
blocks.
Signed-off-by: Valerie Clement <valerie.clement@...l.net>
fs/ext4/balloc.c | 150 ++++++++++++++++++++++++++++++++++--------------
fs/ext4/super.c | 36 ++++++-----
include/linux/ext4_fs.h | 6 +
3 files changed, 133 insertions(+), 59 deletions(-)
Index: linux-2.6.19-rc6/include/linux/ext4_fs.h
===================================================================
--- linux-2.6.19-rc6.orig/include/linux/ext4_fs.h 2006-11-17 12:13:52.000000000 +0100
+++ linux-2.6.19-rc6/include/linux/ext4_fs.h 2006-11-17 12:14:07.000000000 +0100
@@ -151,6 +151,12 @@ struct ext4_group_desc
# define EXT4_DESC_PER_BLOCK(s) (EXT4_SB(s)->s_desc_per_block)
# define EXT4_INODES_PER_GROUP(s) (EXT4_SB(s)->s_inodes_per_group)
# define EXT4_DESC_PER_BLOCK_BITS(s) (EXT4_SB(s)->s_desc_per_block_bits)
+# define EXT4_BITS_PER_BLOCK(s) (EXT4_BLOCK_SIZE(s) << 3)
+# define EXT4_BITS_PER_BLOCK_BITS(s) (EXT4_BLOCK_SIZE_BITS(s) + 3)
+# define EXT4_BLOCK_BITMAP_NBYTES(s) ((EXT4_BLOCKS_PER_GROUP(s) + 7) >> 3)
+# define EXT4_BLOCK_BITMAP_PER_GROUP(s) ((EXT4_BLOCK_BITMAP_NBYTES(s) + (EXT4_BLOCK_SIZE(s) - 1)) >> EXT4_BLOCK_SIZE_BITS(s))
+# define EXT4_INODE_BITMAP_NBYTES(s) ((EXT4_INODES_PER_GROUP(s) + 7) >> 3)
+# define EXT4_INODE_BITMAP_PER_GROUP(s) ((EXT4_INODE_BITMAP_NBYTES(s) + (EXT4_BLOCK_SIZE(s) - 1)) >> EXT4_BLOCK_SIZE_BITS(s))
#else
# define EXT4_BLOCKS_PER_GROUP(s) ((s)->s_blocks_per_group)
# define EXT4_DESC_PER_BLOCK(s) (EXT4_BLOCK_SIZE(s) / EXT4_DESC_SIZE(s))
Index: linux-2.6.19-rc6/fs/ext4/balloc.c
===================================================================
--- linux-2.6.19-rc6.orig/fs/ext4/balloc.c 2006-11-17 12:13:59.000000000 +0100
+++ linux-2.6.19-rc6/fs/ext4/balloc.c 2006-11-17 12:14:07.000000000 +0100
@@ -111,21 +111,22 @@ struct ext4_group_desc * ext4_get_group_
* Return buffer_head on success or NULL in case of failure.
*/
static struct buffer_head *
-read_block_bitmap(struct super_block *sb, unsigned int block_group)
+read_block_bitmap(struct super_block *sb, unsigned int block_group,
+ unsigned int bitmap_block)
{
struct ext4_group_desc * desc;
struct buffer_head * bh = NULL;
- desc = ext4_get_group_desc (sb, block_group, NULL);
+ desc = ext4_get_group_desc(sb, block_group, NULL);
if (!desc)
goto error_out;
- bh = sb_bread(sb, ext4_block_bitmap(sb, desc));
+ bh = sb_bread(sb, bitmap_block + ext4_block_bitmap(sb, desc));
if (!bh)
ext4_error (sb, "read_block_bitmap",
"Cannot read block bitmap - "
"block_group = %d, block_bitmap = %llu",
block_group,
- ext4_block_bitmap(sb, desc));
+ bitmap_block + ext4_block_bitmap(sb, desc));
error_out:
return bh;
}
@@ -442,6 +443,7 @@ void ext4_free_blocks_sb(handle_t *handl
ext4_grpblk_t bit;
unsigned long i;
unsigned long overflow;
+ unsigned long overflow_bitmap;
struct ext4_group_desc * desc;
struct ext4_super_block * es;
struct ext4_sb_info *sbi;
@@ -462,9 +464,17 @@ void ext4_free_blocks_sb(handle_t *handl
ext4_debug ("freeing block(s) %llu-%llu\n", block, block + count - 1);
-do_more:
+do_more_group:
+ group_freed = 0;
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
+ desc = ext4_get_group_desc (sb, block_group, &gd_bh);
+ if (!desc)
+ goto error_return;
+
+do_more_bitmap:
+ overflow_bitmap = 0;
+ ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
@@ -477,20 +487,40 @@ do_more:
if (!desc)
goto error_return;
- if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
- in_range(ext4_inode_bitmap(sb, desc), block, count) ||
- in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
+ if (in_range(block, ext4_block_bitmap(sb, desc),
+ EXT4_BLOCK_BITMAP_PER_GROUP(sb)) ||
+ in_range(block + count - 1, ext4_block_bitmap(sb, desc),
+ EXT4_BLOCK_BITMAP_PER_GROUP(sb)) ||
+ in_range(block, ext4_inode_bitmap(sb, desc),
+ EXT4_INODE_BITMAP_PER_GROUP(sb)) ||
+ in_range(block + count - 1, ext4_inode_bitmap(sb, desc),
+ EXT4_INODE_BITMAP_PER_GROUP(sb)) ||
+ in_range(block, ext4_inode_table(sb, desc),
+ sbi->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, desc),
sbi->s_itb_per_group))
ext4_error (sb, "ext4_free_blocks",
"Freeing blocks in system zones - "
"Block = %llu, count = %lu",
block, count);
+ /* read bitmap */
brelse(bitmap_bh);
- bitmap_bh = read_block_bitmap(sb, block_group);
+ bitmap_bh = read_block_bitmap(sb, block_group,
+ bit >> EXT4_BITS_PER_BLOCK_BITS(sb));
if (!bitmap_bh)
goto error_return;
+ bit &= (EXT4_BITS_PER_BLOCK(sb) - 1);
+
+ /*
+ * check if we are freeing block accross bitmap blocks
+ */
+
+ if (bit + count > EXT4_BITS_PER_BLOCK(sb)) {
+ overflow_bitmap = bit + count - EXT4_BITS_PER_BLOCK(sb);
+ count -= overflow_bitmap;
+ }
+
/*
* We are about to start releasing blocks in the bitmap,
* so we need undo access.
@@ -513,7 +543,7 @@ do_more:
jbd_lock_bh_state(bitmap_bh);
- for (i = 0, group_freed = 0; i < count; i++) {
+ for (i = 0; i < count; i++) {
/*
* An HJ special. This is expensive...
*/
@@ -582,6 +612,16 @@ do_more:
}
jbd_unlock_bh_state(bitmap_bh);
+ /* We dirtied the bitmap block */
+ BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+ err = ext4_journal_dirty_metadata(handle, bitmap_bh);
+
+ if (overflow_bitmap && !err) {
+ block += count;
+ count = overflow_bitmap;
+ goto do_more_bitmap;
+ }
+
spin_lock(sb_bgl_lock(sbi, block_group));
desc->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
@@ -589,11 +629,7 @@ do_more:
spin_unlock(sb_bgl_lock(sbi, block_group));
percpu_counter_mod(&sbi->s_freeblocks_counter, count);
- /* We dirtied the bitmap block */
- BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
- err = ext4_journal_dirty_metadata(handle, bitmap_bh);
-
- /* And the group descriptor block */
+ /* We dirtied the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_journal_dirty_metadata(handle, gd_bh);
if (!err) err = ret;
@@ -602,7 +638,7 @@ do_more:
if (overflow && !err) {
block += count;
count = overflow;
- goto do_more;
+ goto do_more_group;
}
sb->s_dirt = 1;
error_return:
@@ -797,6 +833,7 @@ claim_block(spinlock_t *lock, ext4_grpbl
* @sb: superblock
* @handle: handle to this transaction
* @group: given allocation block group
+ * @bitmap_block:
* @bitmap_bh: bufferhead holds the block bitmap
* @grp_goal: given target block within the group
* @count: target number of blocks to allocate
@@ -818,25 +855,32 @@ claim_block(spinlock_t *lock, ext4_grpbl
*/
static ext4_grpblk_t
ext4_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
- struct buffer_head *bitmap_bh, ext4_grpblk_t grp_goal,
- unsigned long *count, struct ext4_reserve_window *my_rsv)
+ int bitmap_block, struct buffer_head *bitmap_bh,
+ ext4_grpblk_t grp_goal, unsigned long *count,
+ struct ext4_reserve_window *my_rsv)
{
ext4_fsblk_t group_first_block;
ext4_grpblk_t start, end;
unsigned long num = 0;
+ unsigned long offset;
+
+ offset = bitmap_block << EXT4_BITS_PER_BLOCK_BITS(sb);
+ if (grp_goal > 0)
+ grp_goal = grp_goal - offset;
/* we do allocation within the reservation window if we have a window */
if (my_rsv) {
- group_first_block = ext4_group_first_block_no(sb, group);
+ group_first_block = ext4_group_first_block_no(sb, group) +
+ offset;
if (my_rsv->_rsv_start >= group_first_block)
start = my_rsv->_rsv_start - group_first_block;
else
/* reservation window cross group boundary */
start = 0;
end = my_rsv->_rsv_end - group_first_block + 1;
- if (end > EXT4_BLOCKS_PER_GROUP(sb))
- /* reservation window crosses group boundary */
- end = EXT4_BLOCKS_PER_GROUP(sb);
+ if (end > EXT4_BITS_PER_BLOCK(sb))
+ /* reservation window crosses bitmap block boundary */
+ end = EXT4_BITS_PER_BLOCK(sb);
if ((start <= grp_goal) && (grp_goal < end))
start = grp_goal;
else
@@ -846,7 +890,7 @@ ext4_try_to_allocate(struct super_block
start = grp_goal;
else
start = 0;
- end = EXT4_BLOCKS_PER_GROUP(sb);
+ end = EXT4_BITS_PER_BLOCK(sb);
}
BUG_ON(start > EXT4_BLOCKS_PER_GROUP(sb));
@@ -890,7 +934,7 @@ repeat:
grp_goal++;
}
*count = num;
- return grp_goal - num;
+ return offset + grp_goal - num;
fail_access:
*count = num;
return -1;
@@ -1053,7 +1097,8 @@ static int find_next_reservable_window(
*/
static int alloc_new_reservation(struct ext4_reserve_window_node *my_rsv,
ext4_grpblk_t grp_goal, struct super_block *sb,
- unsigned int group, struct buffer_head *bitmap_bh)
+ unsigned int group, unsigned int bitmap_block,
+ struct buffer_head *bitmap_bh)
{
struct ext4_reserve_window_node *search_head;
ext4_fsblk_t group_first_block, group_end_block, start_block;
@@ -1063,13 +1108,15 @@ static int alloc_new_reservation(struct
int ret;
spinlock_t *rsv_lock = &EXT4_SB(sb)->s_rsv_window_lock;
- group_first_block = ext4_group_first_block_no(sb, group);
- group_end_block = group_first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1);
+ group_first_block = ext4_group_first_block_no(sb, group) +
+ (bitmap_block << EXT4_BITS_PER_BLOCK_BITS(sb));
+ group_end_block = group_first_block + (EXT4_BITS_PER_BLOCK(sb) - 1);
if (grp_goal < 0)
start_block = group_first_block;
else
- start_block = grp_goal + group_first_block;
+ start_block = grp_goal + (group_first_block -
+ (bitmap_block << EXT4_BITS_PER_BLOCK_BITS(sb)));
size = my_rsv->rsv_goal_size;
@@ -1147,7 +1194,6 @@ retry:
first_free_block = bitmap_search_next_usable_block(
my_rsv->rsv_start - group_first_block,
bitmap_bh, group_end_block - group_first_block + 1);
-
if (first_free_block < 0) {
/*
* no free block left on the bitmap, no point
@@ -1257,6 +1303,7 @@ ext4_try_to_allocate_with_rsv(struct sup
{
struct buffer_head *bitmap_bh = NULL;
ext4_fsblk_t group_first_block, group_last_block;
+ ext4_fsblk_t bitmap_block;
ext4_grpblk_t ret = 0;
int fatal;
unsigned long num = *count;
@@ -1268,7 +1315,12 @@ ext4_try_to_allocate_with_rsv(struct sup
* that we do the frozen_data COW on bitmap buffers in all cases even
* if the buffer is in BJ_Forget state in the committing transaction.
*/
- bitmap_bh = read_block_bitmap(sb, group);
+ if (grp_goal < 0)
+ bitmap_block = 0;
+ else
+ bitmap_block = grp_goal >> EXT4_BITS_PER_BLOCK_BITS(sb);
+try_next:
+ bitmap_bh = read_block_bitmap(sb, group, bitmap_block);
if (!bitmap_bh) {
*errp = -EIO;
return -1;
@@ -1287,8 +1339,8 @@ ext4_try_to_allocate_with_rsv(struct sup
* or last attempt to allocate a block with reservation turned on failed
*/
if (my_rsv == NULL ) {
- ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh,
- grp_goal, count, NULL);
+ ret = ext4_try_to_allocate(sb, handle, group, bitmap_block,
+ bitmap_bh, grp_goal, count, NULL);
goto out;
}
/*
@@ -1322,7 +1374,7 @@ ext4_try_to_allocate_with_rsv(struct sup
if (my_rsv->rsv_goal_size < *count)
my_rsv->rsv_goal_size = *count;
ret = alloc_new_reservation(my_rsv, grp_goal, sb,
- group, bitmap_bh);
+ group, bitmap_block, bitmap_bh);
if (ret < 0)
break; /* failed */
@@ -1339,7 +1391,7 @@ ext4_try_to_allocate_with_rsv(struct sup
rsv_window_dump(&EXT4_SB(sb)->s_rsv_window_root, 1);
BUG();
}
- ret = ext4_try_to_allocate(sb, handle, group, bitmap_bh,
+ ret = ext4_try_to_allocate(sb, handle, group, bitmap_block, bitmap_bh,
grp_goal, &num, &my_rsv->rsv_window);
if (ret >= 0) {
my_rsv->rsv_alloc_hit += num;
@@ -1390,6 +1442,11 @@ out:
BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
ext4_journal_release_buffer(handle, bitmap_bh);
brelse(bitmap_bh);
+ if (++bitmap_block < EXT4_BLOCK_BITMAP_PER_GROUP(sb)) {
+ if (grp_goal < 0)
+ grp_goal = bitmap_block << EXT4_BITS_PER_BLOCK_BITS(sb);
+ goto try_next;
+ }
return ret;
}
@@ -1606,8 +1663,14 @@ allocated:
ret_block = grp_alloc_blk + ext4_group_first_block_no(sb, group_no);
- if (in_range(ext4_block_bitmap(sb, gdp), ret_block, num) ||
- in_range(ext4_block_bitmap(sb, gdp), ret_block, num) ||
+ if (in_range(ret_block, ext4_block_bitmap(sb, gdp),
+ EXT4_BLOCK_BITMAP_PER_GROUP(sb)) ||
+ in_range(ret_block + num - 1, ext4_block_bitmap(sb, gdp),
+ EXT4_BLOCK_BITMAP_PER_GROUP(sb)) ||
+ in_range(ret_block, ext4_inode_bitmap(sb, gdp),
+ EXT4_INODE_BITMAP_PER_GROUP(sb)) ||
+ in_range(ret_block + num - 1, ext4_inode_bitmap(sb, gdp),
+ EXT4_INODE_BITMAP_PER_GROUP(sb)) ||
in_range(ret_block, ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group) ||
in_range(ret_block + num - 1, ext4_inode_table(sb, gdp),
@@ -1720,12 +1783,15 @@ ext4_fsblk_t ext4_count_free_blocks(stru
if (!gdp)
continue;
desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
- brelse(bitmap_bh);
- bitmap_bh = read_block_bitmap(sb, i);
- if (bitmap_bh == NULL)
- continue;
-
- x = ext4_count_free(bitmap_bh, sb->s_blocksize);
+ for (j = 0, x = 0;
+ j < (EXT4_BLOCKS_PER_GROUP(sb) >> EXT4_BITS_PER_BLOCK_BITS(sb));
+ j++) {
+ brelse(bitmap_bh);
+ bitmap_bh = read_block_bitmap(sb, i, j);
+ if (bitmap_bh == NULL)
+ continue;
+ x += ext4_count_free(bitmap_bh, sb->s_blocksize);
+ }
printk("group %d: stored = %d, counted = %lu\n",
i, le16_to_cpu(gdp->bg_free_blocks_count), x);
bitmap_count += x;
Index: linux-2.6.19-rc6/fs/ext4/super.c
===================================================================
--- linux-2.6.19-rc6.orig/fs/ext4/super.c 2006-11-17 12:13:52.000000000 +0100
+++ linux-2.6.19-rc6/fs/ext4/super.c 2006-11-17 12:14:07.000000000 +0100
@@ -1665,23 +1665,25 @@ static int ext4_fill_super (struct super
sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
sbi->s_def_hash_version = es->s_def_hash_version;
- if (sbi->s_blocks_per_group > blocksize * 8) {
- printk (KERN_ERR
- "EXT4-fs: #blocks per group too big: %lu\n",
- sbi->s_blocks_per_group);
- goto failed_mount;
- }
- if (sbi->s_frags_per_group > blocksize * 8) {
- printk (KERN_ERR
- "EXT4-fs: #fragments per group too big: %lu\n",
- sbi->s_frags_per_group);
- goto failed_mount;
- }
- if (sbi->s_inodes_per_group > blocksize * 8) {
- printk (KERN_ERR
- "EXT4-fs: #inodes per group too big: %lu\n",
- sbi->s_inodes_per_group);
- goto failed_mount;
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT)) {
+ if (sbi->s_blocks_per_group > blocksize * 8) {
+ printk (KERN_ERR
+ "EXT4-fs: #blocks per group too big: %lu\n",
+ sbi->s_blocks_per_group);
+ goto failed_mount;
+ }
+ if (sbi->s_frags_per_group > blocksize * 8) {
+ printk (KERN_ERR
+ "EXT4-fs: #fragments per group too big: %lu\n",
+ sbi->s_frags_per_group);
+ goto failed_mount;
+ }
+ if (sbi->s_inodes_per_group > blocksize * 8) {
+ printk (KERN_ERR
+ "EXT4-fs: #inodes per group too big: %lu\n",
+ sbi->s_inodes_per_group);
+ goto failed_mount;
+ }
}
if (ext4_blocks_count(es) >
-
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