Re: [PATCH] Bring ext2 reservations code in line with latest ext3

From: Martin J. Bligh
Date: Mon Nov 13 2006 - 02:47:45 EST

> s/EXT3/EXT2/ ?

Doh. New copy attached. I did check that ... but only in lower case ;-)

diff -aurpN -X /home/mbligh/.diff.exclude 2.6.18-ext2-akpm/fs/ext2/balloc.c 2.6.18-ext2-mjb/fs/ext2/balloc.c
--- 2.6.18-ext2-akpm/fs/ext2/balloc.c 2006-11-12 13:14:15.000000000 -0800
+++ 2.6.18-ext2-mjb/fs/ext2/balloc.c 2006-11-12 23:44:19.000000000 -0800
@@ -126,15 +126,22 @@ static void group_adjust_blocks(struct s
* Operations include:
* dump, find, add, remove, is_empty, find_next_reservable_window, etc.
*
- * We use sorted double linked list for the per-filesystem reservation
- * window list. (like in vm_region).
+ * We use a red-black tree to represent per-filesystem reservation
+ * windows.
*
- * Initially, we keep those small operations in the abstract functions,
- * so later if we need a better searching tree than double linked-list,
- * we could easily switch to that without changing too much
- * code.
*/
-#if 0
+
+/**
+ * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
+ * @rb_root: root of per-filesystem reservation rb tree
+ * @verbose: verbose mode
+ * @fn: function which wishes to dump the reservation map
+ *
+ * If verbose is turned on, it will print the whole block reservation
+ * windows(start, end). Otherwise, it will only print out the "bad" windows,
+ * those windows that overlap with their immediate neighbors.
+ */
+#if 1
static void __rsv_window_dump(struct rb_root *root, int verbose,
const char *fn)
{
@@ -184,32 +191,51 @@ restart:
#define rsv_window_dump(root, verbose) do {} while (0)
#endif

+/**
+ * goal_in_my_reservation()
+ * @rsv: inode's reservation window
+ * @grp_goal: given goal block relative to the allocation block group
+ * @group: the current allocation block group
+ * @sb: filesystem super block
+ *
+ * Test if the given goal block (group relative) is within the file's
+ * own block reservation window range.
+ *
+ * If the reservation window is outside the goal allocation group, return 0;
+ * grp_goal (given goal block) could be -1, which means no specific
+ * goal block. In this case, always return 1.
+ * If the goal block is within the reservation window, return 1;
+ * otherwise, return 0;
+ */
static int
-goal_in_my_reservation(struct ext2_reserve_window *rsv, int goal,
+goal_in_my_reservation(struct ext2_reserve_window *rsv, ext2_grpblk_t grp_goal,
unsigned int group, struct super_block * sb)
{
- unsigned long group_first_block, group_last_block;
+ ext2_fsblk_t group_first_block, group_last_block;

- group_first_block = le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block) +
- group * EXT2_BLOCKS_PER_GROUP(sb);
+ group_first_block = ext2_group_first_block_no(sb, group);
group_last_block = group_first_block + EXT2_BLOCKS_PER_GROUP(sb) - 1;

if ((rsv->_rsv_start > group_last_block) ||
(rsv->_rsv_end < group_first_block))
return 0;
- if ((goal >= 0) && ((goal + group_first_block < rsv->_rsv_start)
- || (goal + group_first_block > rsv->_rsv_end)))
+ if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
+ || (grp_goal + group_first_block > rsv->_rsv_end)))
return 0;
return 1;
}

-/*
+/**
+ * search_reserve_window()
+ * @rb_root: root of reservation tree
+ * @goal: target allocation block
+ *
* Find the reserved window which includes the goal, or the previous one
* if the goal is not in any window.
* Returns NULL if there are no windows or if all windows start after the goal.
*/
static struct ext2_reserve_window_node *
-search_reserve_window(struct rb_root *root, unsigned long goal)
+search_reserve_window(struct rb_root *root, ext2_fsblk_t goal)
{
struct rb_node *n = root->rb_node;
struct ext2_reserve_window_node *rsv;
@@ -240,12 +266,19 @@ search_reserve_window(struct rb_root *ro
return rsv;
}

+/*
+ * ext2_rsv_window_add() -- Insert a window to the block reservation rb tree.
+ * @sb: super block
+ * @rsv: reservation window to add
+ *
+ * Must be called with rsv_lock held.
+ */
void ext2_rsv_window_add(struct super_block *sb,
struct ext2_reserve_window_node *rsv)
{
struct rb_root *root = &EXT2_SB(sb)->s_rsv_window_root;
struct rb_node *node = &rsv->rsv_node;
- unsigned int start = rsv->rsv_start;
+ ext2_fsblk_t start = rsv->rsv_start;

struct rb_node ** p = &root->rb_node;
struct rb_node * parent = NULL;
@@ -260,14 +293,25 @@ void ext2_rsv_window_add(struct super_bl
p = &(*p)->rb_left;
else if (start > this->rsv_end)
p = &(*p)->rb_right;
- else
+ else {
+ rsv_window_dump(root, 1);
BUG();
+ }
}

rb_link_node(node, parent, p);
rb_insert_color(node, root);
}

+/**
+ * rsv_window_remove() -- unlink a window from the reservation rb tree
+ * @sb: super block
+ * @rsv: reservation window to remove
+ *
+ * Mark the block reservation window as not allocated, and unlink it
+ * from the filesystem reservation window rb tree. Must be called with
+ * rsv_lock held.
+ */
static void rsv_window_remove(struct super_block *sb,
struct ext2_reserve_window_node *rsv)
{
@@ -277,12 +321,39 @@ static void rsv_window_remove(struct sup
rb_erase(&rsv->rsv_node, &EXT2_SB(sb)->s_rsv_window_root);
}

+/*
+ * rsv_is_empty() -- Check if the reservation window is allocated.
+ * @rsv: given reservation window to check
+ *
+ * returns 1 if the end block is EXT2_RESERVE_WINDOW_NOT_ALLOCATED.
+ */
static inline int rsv_is_empty(struct ext2_reserve_window *rsv)
{
/* a valid reservation end block could not be 0 */
return (rsv->_rsv_end == EXT2_RESERVE_WINDOW_NOT_ALLOCATED);
}

+/**
+ * ext2_init_block_alloc_info()
+ * @inode: file inode structure
+ *
+ * Allocate and initialize the reservation window structure, and
+ * link the window to the ext2 inode structure at last
+ *
+ * The reservation window structure is only dynamically allocated
+ * and linked to ext2 inode the first time the open file
+ * needs a new block. So, before every ext2_new_block(s) call, for
+ * regular files, we should check whether the reservation window
+ * structure exists or not. In the latter case, this function is called.
+ * Fail to do so will result in block reservation being turned off for that
+ * open file.
+ *
+ * This function is called from ext2_get_blocks_handle(), also called
+ * when setting the reservation window size through ioctl before the file
+ * is open for write (needs block allocation).
+ *
+ * Needs truncate_mutex protection prior to calling this function.
+ */
void ext2_init_block_alloc_info(struct inode *inode)
{
struct ext2_inode_info *ei = EXT2_I(inode);
@@ -312,6 +383,18 @@ void ext2_init_block_alloc_info(struct i
ei->i_block_alloc_info = block_i;
}

+/**
+ * ext2_discard_reservation()
+ * @inode: inode
+ *
+ * Discard(free) block reservation window on last file close, or truncate
+ * or at last iput().
+ *
+ * It is being called in three cases:
+ * ext2_release_file(): last writer closes the file
+ * ext2_clear_inode(): last iput(), when nobody links to this file.
+ * ext2_truncate(): when the block indirect map is about to change.
+ */
void ext2_discard_reservation(struct inode *inode)
{
struct ext2_inode_info *ei = EXT2_I(inode);
@@ -331,7 +414,12 @@ void ext2_discard_reservation(struct ino
}
}

-/* Free given blocks, update quota and i_blocks field */
+/**
+ * ext2_free_blocks_sb() -- Free given blocks and update quota and i_blocks
+ * @inode: inode
+ * @block: start physcial block to free
+ * @count: number of blocks to free
+ */
void ext2_free_blocks (struct inode * inode, unsigned long block,
unsigned long count)
{
@@ -420,11 +508,21 @@ error_return:
DQUOT_FREE_BLOCK(inode, freed);
}

-static int
-bitmap_search_next_usable_block(int start, struct buffer_head *bh,
- int maxblocks)
+/**
+ * bitmap_search_next_usable_block()
+ * @start: the starting block (group relative) of the search
+ * @bh: bufferhead contains the block group bitmap
+ * @maxblocks: the ending block (group relative) of the reservation
+ *
+ * The bitmap search --- search forward alternately through the actual
+ * bitmap on disk and the last-committed copy in journal, until we find a
+ * bit free in both bitmaps.
+ */
+static ext2_grpblk_t
+bitmap_search_next_usable_block(ext2_grpblk_t start, struct buffer_head *bh,
+ ext2_grpblk_t maxblocks)
{
- int next;
+ ext2_grpblk_t next;

next = ext2_find_next_zero_bit(bh->b_data, maxblocks, start);
if (next >= maxblocks)
@@ -432,16 +530,22 @@ bitmap_search_next_usable_block(int star
return next;
}

-/*
+/**
+ * find_next_usable_block()
+ * @start: the starting block (group relative) to find next
+ * allocatable block in bitmap.
+ * @bh: bufferhead contains the block group bitmap
+ * @maxblocks: the ending block (group relative) for the search
+ *
* Find an allocatable block in a bitmap. We perform the "most
* appropriate allocation" algorithm of looking for a free block near
* the initial goal; then for a free byte somewhere in the bitmap;
* then for any free bit in the bitmap.
*/
-static int
+static ext2_grpblk_t
find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
{
- int here, next;
+ ext2_grpblk_t here, next;
char *p, *r;

if (start > 0) {
@@ -453,7 +557,7 @@ find_next_usable_block(int start, struct
* less than EXT2_BLOCKS_PER_GROUP. Aligning up to the
* next 64-bit boundary is simple..
*/
- int end_goal = (start + 63) & ~63;
+ ext2_grpblk_t end_goal = (start + 63) & ~63;
if (end_goal > maxblocks)
end_goal = maxblocks;
here = ext2_find_next_zero_bit(bh->b_data, end_goal, start);
@@ -478,22 +582,41 @@ find_next_usable_block(int start, struct
}

/*
+ * ext2_try_to_allocate()
+ * @sb: superblock
+ * @handle: handle to this transaction
+ * @group: given allocation block group
+ * @bitmap_bh: bufferhead holds the block bitmap
+ * @grp_goal: given target block within the group
+ * @count: target number of blocks to allocate
+ * @my_rsv: reservation window
+ *
+ * Attempt to allocate blocks within a give range. Set the range of allocation
+ * first, then find the first free bit(s) from the bitmap (within the range),
+ * and at last, allocate the blocks by claiming the found free bit as allocated.
+ *
+ * To set the range of this allocation:
+ * if there is a reservation window, only try to allocate block(s)
+ * from the file's own reservation window;
+ * Otherwise, the allocation range starts from the give goal block,
+ * ends at the block group's last block.
+ *
* If we failed to allocate the desired block then we may end up crossing to a
* new bitmap.
*/
static int
ext2_try_to_allocate(struct super_block *sb, int group,
- struct buffer_head *bitmap_bh, int goal,
- unsigned long *count, struct ext2_reserve_window *my_rsv)
+ struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+ unsigned long *count,
+ struct ext2_reserve_window *my_rsv)
{
- int group_first_block, start, end;
+ ext2_fsblk_t group_first_block;
+ ext2_grpblk_t start, end;
unsigned long num = 0;

/* we do allocation within the reservation window if we have a window */
if (my_rsv) {
- group_first_block =
- le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block) +
- group * EXT2_BLOCKS_PER_GROUP(sb);
+ group_first_block = ext2_group_first_block_no(sb, group);
if (my_rsv->_rsv_start >= group_first_block)
start = my_rsv->_rsv_start - group_first_block;
else
@@ -503,13 +626,13 @@ ext2_try_to_allocate(struct super_block
if (end > EXT2_BLOCKS_PER_GROUP(sb))
/* reservation window crosses group boundary */
end = EXT2_BLOCKS_PER_GROUP(sb);
- if ((start <= goal) && (goal < end))
- start = goal;
+ if ((start <= grp_goal) && (grp_goal < end))
+ start = grp_goal;
else
- goal = -1;
+ grp_goal = -1;
} else {
- if (goal > 0)
- start = goal;
+ if (grp_goal > 0)
+ start = grp_goal;
else
start = 0;
end = EXT2_BLOCKS_PER_GROUP(sb);
@@ -518,41 +641,44 @@ ext2_try_to_allocate(struct super_block
BUG_ON(start > EXT2_BLOCKS_PER_GROUP(sb));

repeat:
- if (goal < 0) {
- goal = find_next_usable_block(start, bitmap_bh, end);
- if (goal < 0)
+ if (grp_goal < 0) {
+ grp_goal = find_next_usable_block(start, bitmap_bh, end);
+ if (grp_goal < 0)
goto fail_access;
if (!my_rsv) {
int i;

- for (i = 0; i < 7 && goal > start &&
- !ext2_test_bit(goal - 1, bitmap_bh->b_data);
- i++, goal--)
+ for (i = 0; i < 7 && grp_goal > start &&
+ !ext2_test_bit(grp_goal - 1,
+ bitmap_bh->b_data);
+ i++, grp_goal--)
;
}
}
- start = goal;
+ start = grp_goal;

- if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), goal, bitmap_bh->b_data)) {
+ if (ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), grp_goal,
+ bitmap_bh->b_data)) {
/*
* The block was allocated by another thread, or it was
* allocated and then freed by another thread
*/
start++;
- goal++;
+ grp_goal++;
if (start >= end)
goto fail_access;
goto repeat;
}
num++;
- goal++;
- while (num < *count && goal < end
- && !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group), goal, bitmap_bh->b_data)) {
+ grp_goal++;
+ while (num < *count && grp_goal < end
+ && !ext2_set_bit_atomic(sb_bgl_lock(EXT2_SB(sb), group),
+ grp_goal, bitmap_bh->b_data)) {
num++;
- goal++;
+ grp_goal++;
}
*count = num;
- return goal - num;
+ return grp_goal - num;
fail_access:
*count = num;
return -1;
@@ -594,12 +720,13 @@ fail_access:
static int find_next_reservable_window(
struct ext2_reserve_window_node *search_head,
struct ext2_reserve_window_node *my_rsv,
- struct super_block * sb, int start_block,
- int last_block)
+ struct super_block * sb,
+ ext2_fsblk_t start_block,
+ ext2_fsblk_t last_block)
{
struct rb_node *next;
struct ext2_reserve_window_node *rsv, *prev;
- int cur;
+ ext2_fsblk_t cur;
int size = my_rsv->rsv_goal_size;

/* TODO: make the start of the reservation window byte-aligned */
@@ -701,7 +828,7 @@ static int find_next_reservable_window(
*
* @rsv: the reservation
*
- * @goal: The goal (group-relative). It is where the search for a
+ * @grp_goal: The goal (group-relative). It is where the search for a
* free reservable space should start from.
* if we have a goal(goal >0 ), then start from there,
* no goal(goal = -1), we start from the first block
@@ -713,25 +840,24 @@ static int find_next_reservable_window(
*
*/
static int alloc_new_reservation(struct ext2_reserve_window_node *my_rsv,
- int goal, struct super_block *sb,
+ ext2_grpblk_t grp_goal, struct super_block *sb,
unsigned int group, struct buffer_head *bitmap_bh)
{
struct ext2_reserve_window_node *search_head;
- int group_first_block, group_end_block, start_block;
- int first_free_block;
+ ext2_fsblk_t group_first_block, group_end_block, start_block;
+ ext2_grpblk_t first_free_block;
struct rb_root *fs_rsv_root = &EXT2_SB(sb)->s_rsv_window_root;
unsigned long size;
int ret;
spinlock_t *rsv_lock = &EXT2_SB(sb)->s_rsv_window_lock;

- group_first_block = le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block) +
- group * EXT2_BLOCKS_PER_GROUP(sb);
- group_end_block = group_first_block + EXT2_BLOCKS_PER_GROUP(sb) - 1;
+ group_first_block = ext2_group_first_block_no(sb, group);
+ group_end_block = group_first_block + (EXT2_BLOCKS_PER_GROUP(sb) - 1);

- if (goal < 0)
+ if (grp_goal < 0)
start_block = group_first_block;
else
- start_block = goal + group_first_block;
+ start_block = grp_goal + group_first_block;

size = my_rsv->rsv_goal_size;

@@ -758,9 +884,10 @@ static int alloc_new_reservation(struct
if ((my_rsv->rsv_alloc_hit >
(my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
/*
- * if we previously allocation hit ration is greater than half
- * we double the size of reservation window next time
- * otherwise keep the same
+ * if the previously allocation hit ratio is
+ * greater than 1/2, then we double the size of
+ * the reservation window the next time,
+ * otherwise we keep the same size window
*/
size = size * 2;
if (size > EXT2_MAX_RESERVE_BLOCKS)
@@ -839,6 +966,23 @@ retry:
goto retry;
}

+/**
+ * try_to_extend_reservation()
+ * @my_rsv: given reservation window
+ * @sb: super block
+ * @size: the delta to extend
+ *
+ * Attempt to expand the reservation window large enough to have
+ * required number of free blocks
+ *
+ * Since ext2_try_to_allocate() will always allocate blocks within
+ * the reservation window range, if the window size is too small,
+ * multiple blocks allocation has to stop at the end of the reservation
+ * window. To make this more efficient, given the total number of
+ * blocks needed and the current size of the window, we try to
+ * expand the reservation window size if necessary on a best-effort
+ * basis before ext2_new_blocks() tries to allocate blocks.
+ */
static void try_to_extend_reservation(struct ext2_reserve_window_node *my_rsv,
struct super_block *sb, int size)
{
@@ -864,7 +1008,15 @@ static void try_to_extend_reservation(st
spin_unlock(rsv_lock);
}

-/*
+/**
+ * ext2_try_to_allocate_with_rsv()
+ * @sb: superblock
+ * @group: given allocation block group
+ * @bitmap_bh: bufferhead holds the block bitmap
+ * @grp_goal: given target block within the group
+ * @count: target number of blocks to allocate
+ * @my_rsv: reservation window
+ *
* This is the main function used to allocate a new block and its reservation
* window.
*
@@ -880,18 +1032,15 @@ static void try_to_extend_reservation(st
* reservation), and there are lots of free blocks, but they are all
* being reserved.
*
- * We use a sorted double linked list for the per-filesystem reservation list.
- * The insert, remove and find a free space(non-reserved) operations for the
- * sorted double linked list should be fast.
- *
+ * We use a red-black tree for the per-filesystem reservation list.
*/
-static int
-ext2_try_to_allocate_with_rsv(struct super_block *sb,
- unsigned int group, struct buffer_head *bitmap_bh,
- int goal, struct ext2_reserve_window_node * my_rsv,
+static ext2_grpblk_t
+ext2_try_to_allocate_with_rsv(struct super_block *sb, unsigned int group,
+ struct buffer_head *bitmap_bh, ext2_grpblk_t grp_goal,
+ struct ext2_reserve_window_node * my_rsv,
unsigned long *count)
{
- unsigned long group_first_block;
+ ext2_fsblk_t group_first_block;
int ret = 0;
unsigned long num = *count;

@@ -903,16 +1052,15 @@ ext2_try_to_allocate_with_rsv(struct sup
*/
if (my_rsv == NULL ) {
return ext2_try_to_allocate(sb, group, bitmap_bh,
- goal, count, NULL);
+ grp_goal, count, NULL);
}
/*
- * goal is a group relative block number (if there is a goal)
- * 0 < goal < EXT2_BLOCKS_PER_GROUP(sb)
+ * grp_goal is a group relative block number (if there is a goal)
+ * 0 < grp_goal < EXT2_BLOCKS_PER_GROUP(sb)
* first block is a filesystem wide block number
* first block is the block number of the first block in this group
*/
- group_first_block = le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block) +
- group * EXT2_BLOCKS_PER_GROUP(sb);
+ group_first_block = ext2_group_first_block_no(sb, group);

/*
* Basically we will allocate a new block from inode's reservation
@@ -931,24 +1079,29 @@ ext2_try_to_allocate_with_rsv(struct sup
*/
while (1) {
if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
- !goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb)) {
+ !goal_in_my_reservation(&my_rsv->rsv_window, grp_goal,
+ group, sb)) {
if (my_rsv->rsv_goal_size < *count)
my_rsv->rsv_goal_size = *count;
- ret = alloc_new_reservation(my_rsv, goal, sb,
+ ret = alloc_new_reservation(my_rsv, grp_goal, sb,
group, bitmap_bh);
if (ret < 0)
break; /* failed */

- if (!goal_in_my_reservation(&my_rsv->rsv_window, goal, group, sb))
- goal = -1;
- } else if (goal > 0 && (my_rsv->rsv_end-goal+1) < *count)
+ if (!goal_in_my_reservation(&my_rsv->rsv_window,
+ grp_goal, group, sb))
+ grp_goal = -1;
+ } else if (grp_goal > 0 &&
+ (my_rsv->rsv_end - grp_goal + 1) < *count)
try_to_extend_reservation(my_rsv, sb,
- *count-my_rsv->rsv_end + goal - 1);
+ *count-my_rsv->rsv_end + grp_goal - 1);

if ((my_rsv->rsv_start >= group_first_block + EXT2_BLOCKS_PER_GROUP(sb))
- || (my_rsv->rsv_end < group_first_block))
+ || (my_rsv->rsv_end < group_first_block)) {
+ rsv_window_dump(&EXT2_SB(sb)->s_rsv_window_root, 1);
BUG();
- ret = ext2_try_to_allocate(sb, group, bitmap_bh, goal,
+ }
+ ret = ext2_try_to_allocate(sb, group, bitmap_bh, grp_goal,
&num, &my_rsv->rsv_window);
if (ret >= 0) {
my_rsv->rsv_alloc_hit += num;
@@ -960,9 +1113,15 @@ ext2_try_to_allocate_with_rsv(struct sup
return ret;
}

+/**
+ * ext2_has_free_blocks()
+ * @sbi: in-core super block structure.
+ *
+ * Check if filesystem has at least 1 free block available for allocation.
+ */
static int ext2_has_free_blocks(struct ext2_sb_info *sbi)
{
- int free_blocks, root_blocks;
+ ext2_fsblk_t free_blocks, root_blocks;

free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
@@ -975,6 +1134,12 @@ static int ext2_has_free_blocks(struct e
}

/*
+ * ext2_new_blocks() -- core block(s) allocation function
+ * @inode: file inode
+ * @goal: given target block(filesystem wide)
+ * @count: target number of blocks to allocate
+ * @errp: error code
+ *
* ext2_new_blocks uses a goal block to assist allocation. If the goal is
* free, or there is a free block within 32 blocks of the goal, that block
* is allocated. Otherwise a forward search is made for a free block; within
@@ -982,18 +1147,18 @@ static int ext2_has_free_blocks(struct e
* bitmap, and then for any free bit if that fails.
* This function also updates quota and i_blocks field.
*/
-int ext2_new_blocks(struct inode *inode, unsigned long goal,
+int ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
unsigned long *count, int *errp)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gdp_bh;
int group_no;
int goal_group;
- int ret_block;
+ ext2_fsblk_t ret_block; /* filesyetem-wide allocated block */
int bgi; /* blockgroup iteration index */
int target_block;
int performed_allocation = 0;
- int free_blocks;
+ ext2_grpblk_t free_blocks; /* number of free blocks in a group */
struct super_block *sb;
struct ext2_group_desc *gdp;
struct ext2_super_block *es;
@@ -1104,6 +1269,9 @@ retry_alloc:
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
+ /*
+ * try to allocate block(s) from this group, without a goal(-1).
+ */
ret_block = ext2_try_to_allocate_with_rsv(sb, group_no,
bitmap_bh, -1, my_rsv, &num);
if (ret_block >= 0)
@@ -1151,7 +1319,7 @@ allocated:

if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
ext2_error(sb, "ext2_new_blocks",
- "block(%d) >= blocks count(%d) - "
+ "block("E2FSBLK") >= blocks count(%d) - "
"block_group = %d, es == %p ", ret_block,
le32_to_cpu(es->s_blocks_count), group_no, es);
goto out;
diff -aurpN -X /home/mbligh/.diff.exclude 2.6.18-ext2-akpm/fs/ext2/inode.c 2.6.18-ext2-mjb/fs/ext2/inode.c
--- 2.6.18-ext2-akpm/fs/ext2/inode.c 2006-11-12 13:14:09.000000000 -0800
+++ 2.6.18-ext2-mjb/fs/ext2/inode.c 2006-11-12 16:11:46.000000000 -0800
@@ -363,13 +363,13 @@ ext2_blks_to_allocate(Indirect * branch,
* direct blocks
*/
static int ext2_alloc_blocks(struct inode *inode,
- unsigned long goal, int indirect_blks, int blks,
- unsigned long long new_blocks[4], int *err)
+ ext2_fsblk_t goal, int indirect_blks, int blks,
+ ext2_fsblk_t new_blocks[4], int *err)
{
int target, i;
unsigned long count = 0;
int index = 0;
- unsigned long current_block = 0;
+ ext2_fsblk_t current_block = 0;
int ret = 0;

/*
@@ -439,7 +439,7 @@ failed_out:
*/

static int ext2_alloc_branch(struct inode *inode,
- int indirect_blks, int *blks, unsigned long goal,
+ int indirect_blks, int *blks, ext2_fsblk_t goal,
int *offsets, Indirect *branch)
{
int blocksize = inode->i_sb->s_blocksize;
@@ -447,8 +447,8 @@ static int ext2_alloc_branch(struct inod
int err = 0;
struct buffer_head *bh;
int num;
- unsigned long long new_blocks[4];
- unsigned long long current_block;
+ ext2_fsblk_t new_blocks[4];
+ ext2_fsblk_t current_block;

num = ext2_alloc_blocks(inode, goal, indirect_blks,
*blks, new_blocks, &err);
@@ -515,7 +515,7 @@ static void ext2_splice_branch(struct in
{
int i;
struct ext2_block_alloc_info *block_i;
- unsigned long current_block;
+ ext2_fsblk_t current_block;

block_i = EXT2_I(inode)->i_block_alloc_info;

@@ -583,13 +583,13 @@ int ext2_get_blocks(struct inode *inode,
int offsets[4];
Indirect chain[4];
Indirect *partial;
- unsigned long goal;
+ ext2_fsblk_t goal;
int indirect_blks;
int blocks_to_boundary = 0;
int depth;
struct ext2_inode_info *ei = EXT2_I(inode);
int count = 0;
- unsigned long first_block = 0;
+ ext2_fsblk_t first_block = 0;

depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);

@@ -605,7 +605,7 @@ reread:
count++;
/*map more blocks*/
while (count < maxblocks && count <= blocks_to_boundary) {
- unsigned long blk;
+ ext2_fsblk_t blk;

if (!verify_chain(chain, partial)) {
/*
diff -aurpN -X /home/mbligh/.diff.exclude 2.6.18-ext2-akpm/include/linux/ext2_fs.h 2.6.18-ext2-mjb/include/linux/ext2_fs.h
--- 2.6.18-ext2-akpm/include/linux/ext2_fs.h 2006-11-04 14:56:36.000000000 -0800
+++ 2.6.18-ext2-mjb/include/linux/ext2_fs.h 2006-11-12 16:37:36.000000000 -0800
@@ -558,4 +558,11 @@ enum {
#define EXT2_DIR_REC_LEN(name_len) (((name_len) + 8 + EXT2_DIR_ROUND) & \
~EXT2_DIR_ROUND)

+static inline ext2_fsblk_t
+ext2_group_first_block_no(struct super_block *sb, unsigned long group_no)
+{
+ return group_no * (ext2_fsblk_t)EXT2_BLOCKS_PER_GROUP(sb) +
+ le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block);
+}
+
#endif /* _LINUX_EXT2_FS_H */
diff -aurpN -X /home/mbligh/.diff.exclude 2.6.18-ext2-akpm/include/linux/ext2_fs_sb.h 2.6.18-ext2-mjb/include/linux/ext2_fs_sb.h
--- 2.6.18-ext2-akpm/include/linux/ext2_fs_sb.h 2006-11-04 14:56:36.000000000 -0800
+++ 2.6.18-ext2-mjb/include/linux/ext2_fs_sb.h 2006-11-12 16:38:16.000000000 -0800
@@ -22,6 +22,14 @@

/* XXX Here for now... not interested in restructing headers JUST now */

+/* data type for block offset of block group */
+typedef int ext2_grpblk_t;
+
+/* data type for filesystem-wide blocks number */
+typedef unsigned long ext2_fsblk_t;
+
+#define E2FSBLK "%lu"
+
struct ext2_reserve_window {
__u32 _rsv_start; /* First byte reserved */
__u32 _rsv_end; /* Last byte reserved or 0 */