4 * Copyright (C) 2001 Theodore Ts'o. This file may be
5 * redistributed under the terms of the GNU Public License.
21 * The strategy we use for keeping track of EA refcounts is as
22 * follows. We keep a sorted array of first EA blocks and its
23 * reference counts. Once the refcount has dropped to zero, it is
24 * removed from the array to save memory space. Once the EA block is
25 * checked, its bit is set in the block_ea_map bitmap.
27 struct ea_refcount_el
{
28 /* ea_key could either be an inode number or block number. */
37 struct ea_refcount_el
*list
;
40 void ea_refcount_free(ext2_refcount_t refcount
)
46 ext2fs_free_mem(&refcount
->list
);
47 ext2fs_free_mem(&refcount
);
50 errcode_t
ea_refcount_create(size_t size
, ext2_refcount_t
*ret
)
52 ext2_refcount_t refcount
;
56 retval
= ext2fs_get_memzero(sizeof(struct ea_refcount
), &refcount
);
62 refcount
->size
= size
;
63 bytes
= size
* sizeof(struct ea_refcount_el
);
65 printf("Refcount allocated %zu entries, %zu bytes.\n",
66 refcount
->size
, bytes
);
68 retval
= ext2fs_get_memzero(bytes
, &refcount
->list
);
79 ea_refcount_free(refcount
);
84 * collapse_refcount() --- go through the refcount array, and get rid
85 * of any count == zero entries
87 static void refcount_collapse(ext2_refcount_t refcount
)
90 struct ea_refcount_el
*list
;
92 list
= refcount
->list
;
93 for (i
= 0, j
= 0; i
< refcount
->count
; i
++) {
94 if (list
[i
].ea_value
) {
100 #if defined(DEBUG) || defined(TEST_PROGRAM)
101 printf("Refcount_collapse: size was %zu, now %d\n",
109 * insert_refcount_el() --- Insert a new entry into the sorted list at a
110 * specified position.
112 static struct ea_refcount_el
*insert_refcount_el(ext2_refcount_t refcount
,
113 ea_key_t ea_key
, int pos
)
115 struct ea_refcount_el
*el
;
120 if (refcount
->count
>= refcount
->size
) {
121 new_size
= refcount
->size
+ 100;
123 printf("Reallocating refcount %d entries...\n", new_size
);
125 retval
= ext2fs_resize_mem((size_t) refcount
->size
*
126 sizeof(struct ea_refcount_el
),
128 sizeof(struct ea_refcount_el
),
132 refcount
->size
= new_size
;
134 num
= (int) refcount
->count
- pos
;
136 return 0; /* should never happen */
138 memmove(&refcount
->list
[pos
+1], &refcount
->list
[pos
],
139 sizeof(struct ea_refcount_el
) * num
);
142 el
= &refcount
->list
[pos
];
150 * get_refcount_el() --- given an block number, try to find refcount
151 * information in the sorted list. If the create flag is set,
152 * and we can't find an entry, create one in the sorted list.
154 static struct ea_refcount_el
*get_refcount_el(ext2_refcount_t refcount
,
155 ea_key_t ea_key
, int create
)
159 if (!refcount
|| !refcount
->list
)
163 high
= (int) refcount
->count
-1;
164 if (create
&& ((refcount
->count
== 0) ||
165 (ea_key
> refcount
->list
[high
].ea_key
))) {
166 if (refcount
->count
>= refcount
->size
)
167 refcount_collapse(refcount
);
169 return insert_refcount_el(refcount
, ea_key
,
170 (unsigned) refcount
->count
);
172 if (refcount
->count
== 0)
175 if (refcount
->cursor
>= refcount
->count
)
176 refcount
->cursor
= 0;
177 if (ea_key
== refcount
->list
[refcount
->cursor
].ea_key
)
178 return &refcount
->list
[refcount
->cursor
++];
180 printf("Non-cursor get_refcount_el: %u\n", ea_key
);
182 while (low
<= high
) {
184 if (ea_key
== refcount
->list
[mid
].ea_key
) {
185 refcount
->cursor
= mid
+1;
186 return &refcount
->list
[mid
];
188 if (ea_key
< refcount
->list
[mid
].ea_key
)
194 * If we need to create a new entry, it should be right at
195 * low (where high will be left at low-1).
198 if (refcount
->count
>= refcount
->size
) {
199 refcount_collapse(refcount
);
200 if (refcount
->count
< refcount
->size
)
203 return insert_refcount_el(refcount
, ea_key
, low
);
208 errcode_t
ea_refcount_fetch(ext2_refcount_t refcount
, ea_key_t ea_key
,
211 struct ea_refcount_el
*el
;
213 el
= get_refcount_el(refcount
, ea_key
, 0);
222 errcode_t
ea_refcount_increment(ext2_refcount_t refcount
, ea_key_t ea_key
,
225 struct ea_refcount_el
*el
;
227 el
= get_refcount_el(refcount
, ea_key
, 1);
229 return EXT2_ET_NO_MEMORY
;
237 errcode_t
ea_refcount_decrement(ext2_refcount_t refcount
, ea_key_t ea_key
,
240 struct ea_refcount_el
*el
;
242 el
= get_refcount_el(refcount
, ea_key
, 0);
243 if (!el
|| el
->ea_value
== 0)
244 return EXT2_ET_INVALID_ARGUMENT
;
253 errcode_t
ea_refcount_store(ext2_refcount_t refcount
, ea_key_t ea_key
,
256 struct ea_refcount_el
*el
;
259 * Get the refcount element
261 el
= get_refcount_el(refcount
, ea_key
, ea_value
? 1 : 0);
263 return ea_value
? EXT2_ET_NO_MEMORY
: 0;
264 el
->ea_value
= ea_value
;
268 size_t ext2fs_get_refcount_size(ext2_refcount_t refcount
)
273 return refcount
->size
;
276 void ea_refcount_intr_begin(ext2_refcount_t refcount
)
278 refcount
->cursor
= 0;
281 ea_key_t
ea_refcount_intr_next(ext2_refcount_t refcount
,
284 struct ea_refcount_el
*list
;
287 if (refcount
->cursor
>= refcount
->count
)
289 list
= refcount
->list
;
290 if (list
[refcount
->cursor
].ea_value
) {
292 *ret
= list
[refcount
->cursor
].ea_value
;
293 return list
[refcount
->cursor
++].ea_key
;
302 errcode_t
ea_refcount_validate(ext2_refcount_t refcount
, FILE *out
)
306 const char *bad
= "bad refcount";
308 if (refcount
->count
> refcount
->size
) {
309 fprintf(out
, "%s: count > size\n", bad
);
310 return EXT2_ET_INVALID_ARGUMENT
;
312 for (i
=1; i
< refcount
->count
; i
++) {
313 if (refcount
->list
[i
-1].ea_key
>= refcount
->list
[i
].ea_key
) {
315 "%s: list[%d].ea_key=%llu, list[%d].ea_key=%llu\n",
317 (unsigned long long) refcount
->list
[i
-1].ea_key
,
319 (unsigned long long) refcount
->list
[i
].ea_key
);
320 ret
= EXT2_ET_INVALID_ARGUMENT
;
327 #define BCODE_CREATE 1
329 #define BCODE_STORE 3
332 #define BCODE_FETCH 6
333 #define BCODE_VALIDATE 7
335 #define BCODE_COLLAPSE 9
337 int bcode_program
[] = {
372 int main(int argc
, char **argv
)
375 ext2_refcount_t refcount
;
382 switch (bcode_program
[i
++]) {
386 size
= bcode_program
[i
++];
387 retval
= ea_refcount_create(size
, &refcount
);
389 com_err("ea_refcount_create", retval
,
390 "while creating size %zu", size
);
393 printf("Creating refcount with size %zu\n",
397 ea_refcount_free(refcount
);
399 printf("Freeing refcount\n");
402 ea_key
= (size_t) bcode_program
[i
++];
403 arg
= bcode_program
[i
++];
404 printf("Storing ea_key %llu with value %llu\n",
405 (unsigned long long) ea_key
,
406 (unsigned long long) arg
);
407 retval
= ea_refcount_store(refcount
, ea_key
, arg
);
409 com_err("ea_refcount_store", retval
,
410 "while storing ea_key %llu",
411 (unsigned long long) ea_key
);
414 ea_key
= (size_t) bcode_program
[i
++];
415 retval
= ea_refcount_fetch(refcount
, ea_key
, &arg
);
417 com_err("ea_refcount_fetch", retval
,
418 "while fetching ea_key %llu",
419 (unsigned long long) ea_key
);
421 printf("bcode_fetch(%llu) returns %llu\n",
422 (unsigned long long) ea_key
,
423 (unsigned long long) arg
);
426 ea_key
= (size_t) bcode_program
[i
++];
427 retval
= ea_refcount_increment(refcount
, ea_key
, &arg
);
429 com_err("ea_refcount_increment", retval
,
430 "while incrementing ea_key %llu",
431 (unsigned long long) ea_key
);
433 printf("bcode_increment(%llu) returns %llu\n",
434 (unsigned long long) ea_key
,
435 (unsigned long long) arg
);
438 ea_key
= (size_t) bcode_program
[i
++];
439 retval
= ea_refcount_decrement(refcount
, ea_key
, &arg
);
441 com_err("ea_refcount_decrement", retval
,
442 "while decrementing ea_key %llu",
443 (unsigned long long) ea_key
);
445 printf("bcode_decrement(%llu) returns %llu\n",
446 (unsigned long long) ea_key
,
447 (unsigned long long) arg
);
450 retval
= ea_refcount_validate(refcount
, stderr
);
452 com_err("ea_refcount_validate", retval
,
455 printf("Refcount validation OK.\n");
458 ea_refcount_intr_begin(refcount
);
460 ea_key
= ea_refcount_intr_next(refcount
, &arg
);
463 printf("\tea_key=%llu, count=%llu\n",
464 (unsigned long long) ea_key
,
465 (unsigned long long) arg
);
469 refcount_collapse(refcount
);