Revision 38e87880666091fe9c572a7a2ed2e771d97ca5aa authored by Chris Mason on 10 June 2011, 20:36:57 UTC, committed by Chris Mason on 10 June 2011, 20:36:57 UTC
Josef recently changed the free extent cache to look in the block group cluster for any bitmaps before trying to add a new bitmap for the same offset. This avoids BUG_ON()s due covering duplicate ranges. But it didn't go quite far enough. A given free range might span between one or more bitmaps or free space entries. The code has looping to cover this, but it doesn't check for clustered bitmaps every time. This shuffles our gotos to check for a bitmap in the cluster for every new bitmap entry we try to add. Signed-off-by: Chris Mason <chris.mason@oracle.com>
1 parent 3473f3c
list_sort.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list_sort.h>
#include <linux/slab.h>
#include <linux/list.h>
#define MAX_LIST_LENGTH_BITS 20
/*
* Returns a list organized in an intermediate format suited
* to chaining of merge() calls: null-terminated, no reserved or
* sentinel head node, "prev" links not maintained.
*/
static struct list_head *merge(void *priv,
int (*cmp)(void *priv, struct list_head *a,
struct list_head *b),
struct list_head *a, struct list_head *b)
{
struct list_head head, *tail = &head;
while (a && b) {
/* if equal, take 'a' -- important for sort stability */
if ((*cmp)(priv, a, b) <= 0) {
tail->next = a;
a = a->next;
} else {
tail->next = b;
b = b->next;
}
tail = tail->next;
}
tail->next = a?:b;
return head.next;
}
/*
* Combine final list merge with restoration of standard doubly-linked
* list structure. This approach duplicates code from merge(), but
* runs faster than the tidier alternatives of either a separate final
* prev-link restoration pass, or maintaining the prev links
* throughout.
*/
static void merge_and_restore_back_links(void *priv,
int (*cmp)(void *priv, struct list_head *a,
struct list_head *b),
struct list_head *head,
struct list_head *a, struct list_head *b)
{
struct list_head *tail = head;
while (a && b) {
/* if equal, take 'a' -- important for sort stability */
if ((*cmp)(priv, a, b) <= 0) {
tail->next = a;
a->prev = tail;
a = a->next;
} else {
tail->next = b;
b->prev = tail;
b = b->next;
}
tail = tail->next;
}
tail->next = a ? : b;
do {
/*
* In worst cases this loop may run many iterations.
* Continue callbacks to the client even though no
* element comparison is needed, so the client's cmp()
* routine can invoke cond_resched() periodically.
*/
(*cmp)(priv, tail->next, tail->next);
tail->next->prev = tail;
tail = tail->next;
} while (tail->next);
tail->next = head;
head->prev = tail;
}
/**
* list_sort - sort a list
* @priv: private data, opaque to list_sort(), passed to @cmp
* @head: the list to sort
* @cmp: the elements comparison function
*
* This function implements "merge sort", which has O(nlog(n))
* complexity.
*
* The comparison function @cmp must return a negative value if @a
* should sort before @b, and a positive value if @a should sort after
* @b. If @a and @b are equivalent, and their original relative
* ordering is to be preserved, @cmp must return 0.
*/
void list_sort(void *priv, struct list_head *head,
int (*cmp)(void *priv, struct list_head *a,
struct list_head *b))
{
struct list_head *part[MAX_LIST_LENGTH_BITS+1]; /* sorted partial lists
-- last slot is a sentinel */
int lev; /* index into part[] */
int max_lev = 0;
struct list_head *list;
if (list_empty(head))
return;
memset(part, 0, sizeof(part));
head->prev->next = NULL;
list = head->next;
while (list) {
struct list_head *cur = list;
list = list->next;
cur->next = NULL;
for (lev = 0; part[lev]; lev++) {
cur = merge(priv, cmp, part[lev], cur);
part[lev] = NULL;
}
if (lev > max_lev) {
if (unlikely(lev >= ARRAY_SIZE(part)-1)) {
printk_once(KERN_DEBUG "list passed to"
" list_sort() too long for"
" efficiency\n");
lev--;
}
max_lev = lev;
}
part[lev] = cur;
}
for (lev = 0; lev < max_lev; lev++)
if (part[lev])
list = merge(priv, cmp, part[lev], list);
merge_and_restore_back_links(priv, cmp, head, part[max_lev], list);
}
EXPORT_SYMBOL(list_sort);
#ifdef CONFIG_TEST_LIST_SORT
#include <linux/random.h>
/*
* The pattern of set bits in the list length determines which cases
* are hit in list_sort().
*/
#define TEST_LIST_LEN (512+128+2) /* not including head */
#define TEST_POISON1 0xDEADBEEF
#define TEST_POISON2 0xA324354C
struct debug_el {
unsigned int poison1;
struct list_head list;
unsigned int poison2;
int value;
unsigned serial;
};
/* Array, containing pointers to all elements in the test list */
static struct debug_el **elts __initdata;
static int __init check(struct debug_el *ela, struct debug_el *elb)
{
if (ela->serial >= TEST_LIST_LEN) {
printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
ela->serial);
return -EINVAL;
}
if (elb->serial >= TEST_LIST_LEN) {
printk(KERN_ERR "list_sort_test: error: incorrect serial %d\n",
elb->serial);
return -EINVAL;
}
if (elts[ela->serial] != ela || elts[elb->serial] != elb) {
printk(KERN_ERR "list_sort_test: error: phantom element\n");
return -EINVAL;
}
if (ela->poison1 != TEST_POISON1 || ela->poison2 != TEST_POISON2) {
printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
ela->poison1, ela->poison2);
return -EINVAL;
}
if (elb->poison1 != TEST_POISON1 || elb->poison2 != TEST_POISON2) {
printk(KERN_ERR "list_sort_test: error: bad poison: %#x/%#x\n",
elb->poison1, elb->poison2);
return -EINVAL;
}
return 0;
}
static int __init cmp(void *priv, struct list_head *a, struct list_head *b)
{
struct debug_el *ela, *elb;
ela = container_of(a, struct debug_el, list);
elb = container_of(b, struct debug_el, list);
check(ela, elb);
return ela->value - elb->value;
}
static int __init list_sort_test(void)
{
int i, count = 1, err = -EINVAL;
struct debug_el *el;
struct list_head *cur, *tmp;
LIST_HEAD(head);
printk(KERN_DEBUG "list_sort_test: start testing list_sort()\n");
elts = kmalloc(sizeof(void *) * TEST_LIST_LEN, GFP_KERNEL);
if (!elts) {
printk(KERN_ERR "list_sort_test: error: cannot allocate "
"memory\n");
goto exit;
}
for (i = 0; i < TEST_LIST_LEN; i++) {
el = kmalloc(sizeof(*el), GFP_KERNEL);
if (!el) {
printk(KERN_ERR "list_sort_test: error: cannot "
"allocate memory\n");
goto exit;
}
/* force some equivalencies */
el->value = random32() % (TEST_LIST_LEN/3);
el->serial = i;
el->poison1 = TEST_POISON1;
el->poison2 = TEST_POISON2;
elts[i] = el;
list_add_tail(&el->list, &head);
}
list_sort(NULL, &head, cmp);
for (cur = head.next; cur->next != &head; cur = cur->next) {
struct debug_el *el1;
int cmp_result;
if (cur->next->prev != cur) {
printk(KERN_ERR "list_sort_test: error: list is "
"corrupted\n");
goto exit;
}
cmp_result = cmp(NULL, cur, cur->next);
if (cmp_result > 0) {
printk(KERN_ERR "list_sort_test: error: list is not "
"sorted\n");
goto exit;
}
el = container_of(cur, struct debug_el, list);
el1 = container_of(cur->next, struct debug_el, list);
if (cmp_result == 0 && el->serial >= el1->serial) {
printk(KERN_ERR "list_sort_test: error: order of "
"equivalent elements not preserved\n");
goto exit;
}
if (check(el, el1)) {
printk(KERN_ERR "list_sort_test: error: element check "
"failed\n");
goto exit;
}
count++;
}
if (count != TEST_LIST_LEN) {
printk(KERN_ERR "list_sort_test: error: bad list length %d",
count);
goto exit;
}
err = 0;
exit:
kfree(elts);
list_for_each_safe(cur, tmp, &head) {
list_del(cur);
kfree(container_of(cur, struct debug_el, list));
}
return err;
}
module_init(list_sort_test);
#endif /* CONFIG_TEST_LIST_SORT */
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