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git.ipfire.org Git - thirdparty/e2fsprogs.git/blob - e2fsck/ea_refcount.c
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_mem(sizeof(struct ea_refcount
), &refcount
);
59 memset(refcount
, 0, sizeof(struct ea_refcount
));
63 refcount
->size
= size
;
64 bytes
= size
* sizeof(struct ea_refcount_el
);
66 printf("Refcount allocated %zu entries, %zu bytes.\n",
67 refcount
->size
, bytes
);
69 retval
= ext2fs_get_mem(bytes
, &refcount
->list
);
72 memset(refcount
->list
, 0, bytes
);
81 ea_refcount_free(refcount
);
86 * collapse_refcount() --- go through the refcount array, and get rid
87 * of any count == zero entries
89 static void refcount_collapse(ext2_refcount_t refcount
)
92 struct ea_refcount_el
*list
;
94 list
= refcount
->list
;
95 for (i
= 0, j
= 0; i
< refcount
->count
; i
++) {
96 if (list
[i
].ea_value
) {
102 #if defined(DEBUG) || defined(TEST_PROGRAM)
103 printf("Refcount_collapse: size was %zu, now %d\n",
111 * insert_refcount_el() --- Insert a new entry into the sorted list at a
112 * specified position.
114 static struct ea_refcount_el
*insert_refcount_el(ext2_refcount_t refcount
,
115 ea_key_t ea_key
, int pos
)
117 struct ea_refcount_el
*el
;
122 if (refcount
->count
>= refcount
->size
) {
123 new_size
= refcount
->size
+ 100;
125 printf("Reallocating refcount %d entries...\n", new_size
);
127 retval
= ext2fs_resize_mem((size_t) refcount
->size
*
128 sizeof(struct ea_refcount_el
),
130 sizeof(struct ea_refcount_el
),
134 refcount
->size
= new_size
;
136 num
= (int) refcount
->count
- pos
;
138 return 0; /* should never happen */
140 memmove(&refcount
->list
[pos
+1], &refcount
->list
[pos
],
141 sizeof(struct ea_refcount_el
) * num
);
144 el
= &refcount
->list
[pos
];
152 * get_refcount_el() --- given an block number, try to find refcount
153 * information in the sorted list. If the create flag is set,
154 * and we can't find an entry, create one in the sorted list.
156 static struct ea_refcount_el
*get_refcount_el(ext2_refcount_t refcount
,
157 ea_key_t ea_key
, int create
)
161 if (!refcount
|| !refcount
->list
)
165 high
= (int) refcount
->count
-1;
166 if (create
&& ((refcount
->count
== 0) ||
167 (ea_key
> refcount
->list
[high
].ea_key
))) {
168 if (refcount
->count
>= refcount
->size
)
169 refcount_collapse(refcount
);
171 return insert_refcount_el(refcount
, ea_key
,
172 (unsigned) refcount
->count
);
174 if (refcount
->count
== 0)
177 if (refcount
->cursor
>= refcount
->count
)
178 refcount
->cursor
= 0;
179 if (ea_key
== refcount
->list
[refcount
->cursor
].ea_key
)
180 return &refcount
->list
[refcount
->cursor
++];
182 printf("Non-cursor get_refcount_el: %u\n", ea_key
);
184 while (low
<= high
) {
186 if (ea_key
== refcount
->list
[mid
].ea_key
) {
187 refcount
->cursor
= mid
+1;
188 return &refcount
->list
[mid
];
190 if (ea_key
< refcount
->list
[mid
].ea_key
)
196 * If we need to create a new entry, it should be right at
197 * low (where high will be left at low-1).
200 if (refcount
->count
>= refcount
->size
) {
201 refcount_collapse(refcount
);
202 if (refcount
->count
< refcount
->size
)
205 return insert_refcount_el(refcount
, ea_key
, low
);
210 errcode_t
ea_refcount_fetch(ext2_refcount_t refcount
, ea_key_t ea_key
,
213 struct ea_refcount_el
*el
;
215 el
= get_refcount_el(refcount
, ea_key
, 0);
224 errcode_t
ea_refcount_increment(ext2_refcount_t refcount
, ea_key_t ea_key
,
227 struct ea_refcount_el
*el
;
229 el
= get_refcount_el(refcount
, ea_key
, 1);
231 return EXT2_ET_NO_MEMORY
;
239 errcode_t
ea_refcount_decrement(ext2_refcount_t refcount
, ea_key_t ea_key
,
242 struct ea_refcount_el
*el
;
244 el
= get_refcount_el(refcount
, ea_key
, 0);
245 if (!el
|| el
->ea_value
== 0)
246 return EXT2_ET_INVALID_ARGUMENT
;
255 errcode_t
ea_refcount_store(ext2_refcount_t refcount
, ea_key_t ea_key
,
258 struct ea_refcount_el
*el
;
261 * Get the refcount element
263 el
= get_refcount_el(refcount
, ea_key
, ea_value
? 1 : 0);
265 return ea_value
? EXT2_ET_NO_MEMORY
: 0;
266 el
->ea_value
= ea_value
;
270 size_t ext2fs_get_refcount_size(ext2_refcount_t refcount
)
275 return refcount
->size
;
278 void ea_refcount_intr_begin(ext2_refcount_t refcount
)
280 refcount
->cursor
= 0;
283 ea_key_t
ea_refcount_intr_next(ext2_refcount_t refcount
,
286 struct ea_refcount_el
*list
;
289 if (refcount
->cursor
>= refcount
->count
)
291 list
= refcount
->list
;
292 if (list
[refcount
->cursor
].ea_value
) {
294 *ret
= list
[refcount
->cursor
].ea_value
;
295 return list
[refcount
->cursor
++].ea_key
;
304 errcode_t
ea_refcount_validate(ext2_refcount_t refcount
, FILE *out
)
308 const char *bad
= "bad refcount";
310 if (refcount
->count
> refcount
->size
) {
311 fprintf(out
, "%s: count > size\n", bad
);
312 return EXT2_ET_INVALID_ARGUMENT
;
314 for (i
=1; i
< refcount
->count
; i
++) {
315 if (refcount
->list
[i
-1].ea_key
>= refcount
->list
[i
].ea_key
) {
317 "%s: list[%d].ea_key=%llu, list[%d].ea_key=%llu\n",
318 bad
, i
-1, refcount
->list
[i
-1].ea_key
, i
,
319 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", ea_key
,
406 retval
= ea_refcount_store(refcount
, ea_key
, arg
);
408 com_err("ea_refcount_store", retval
,
409 "while storing ea_key %llu", ea_key
);
412 ea_key
= (size_t) bcode_program
[i
++];
413 retval
= ea_refcount_fetch(refcount
, ea_key
, &arg
);
415 com_err("ea_refcount_fetch", retval
,
416 "while fetching ea_key %llu", ea_key
);
418 printf("bcode_fetch(%llu) returns %llu\n",
422 ea_key
= (size_t) bcode_program
[i
++];
423 retval
= ea_refcount_increment(refcount
, ea_key
, &arg
);
425 com_err("ea_refcount_increment", retval
,
426 "while incrementing ea_key %llu",
429 printf("bcode_increment(%llu) returns %llu\n",
433 ea_key
= (size_t) bcode_program
[i
++];
434 retval
= ea_refcount_decrement(refcount
, ea_key
, &arg
);
436 com_err("ea_refcount_decrement", retval
,
437 "while decrementing ea_key %llu",
440 printf("bcode_decrement(%llu) returns %llu\n",
444 retval
= ea_refcount_validate(refcount
, stderr
);
446 com_err("ea_refcount_validate", retval
,
449 printf("Refcount validation OK.\n");
452 ea_refcount_intr_begin(refcount
);
454 ea_key
= ea_refcount_intr_next(refcount
, &arg
);
457 printf("\tea_key=%llu, count=%llu\n", ea_key
,
462 refcount_collapse(refcount
);