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Diffstat (limited to 'e2fsprogs/e2fsck/ea_refcount.c')
-rw-r--r--e2fsprogs/e2fsck/ea_refcount.c479
1 files changed, 479 insertions, 0 deletions
diff --git a/e2fsprogs/e2fsck/ea_refcount.c b/e2fsprogs/e2fsck/ea_refcount.c
new file mode 100644
index 000000000..6420c7280
--- /dev/null
+++ b/e2fsprogs/e2fsck/ea_refcount.c
@@ -0,0 +1,479 @@
+/*
+ * ea_refcount.c
+ *
+ * Copyright (C) 2001 Theodore Ts'o. This file may be
+ * redistributed under the terms of the GNU Public License.
+ */
+
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <string.h>
+#include <stdio.h>
+
+#include "e2fsck.h"
+
+/*
+ * The strategy we use for keeping track of EA refcounts is as
+ * follows. We keep a sorted array of first EA blocks and its
+ * reference counts. Once the refcount has dropped to zero, it is
+ * removed from the array to save memory space. Once the EA block is
+ * checked, its bit is set in the block_ea_map bitmap.
+ */
+struct ea_refcount_el {
+ blk_t ea_blk;
+ int ea_count;
+};
+
+struct ea_refcount {
+ blk_t count;
+ blk_t size;
+ blk_t cursor;
+ struct ea_refcount_el *list;
+};
+
+void ea_refcount_free(ext2_refcount_t refcount)
+{
+ if (!refcount)
+ return;
+
+ if (refcount->list)
+ ext2fs_free_mem(&refcount->list);
+ ext2fs_free_mem(&refcount);
+}
+
+errcode_t ea_refcount_create(int size, ext2_refcount_t *ret)
+{
+ ext2_refcount_t refcount;
+ errcode_t retval;
+ size_t bytes;
+
+ retval = ext2fs_get_mem(sizeof(struct ea_refcount), &refcount);
+ if (retval)
+ return retval;
+ memset(refcount, 0, sizeof(struct ea_refcount));
+
+ if (!size)
+ size = 500;
+ refcount->size = size;
+ bytes = (size_t) (size * sizeof(struct ea_refcount_el));
+#ifdef DEBUG
+ printf("Refcount allocated %d entries, %d bytes.\n",
+ refcount->size, bytes);
+#endif
+ retval = ext2fs_get_mem(bytes, &refcount->list);
+ if (retval)
+ goto errout;
+ memset(refcount->list, 0, bytes);
+
+ refcount->count = 0;
+ refcount->cursor = 0;
+
+ *ret = refcount;
+ return 0;
+
+errout:
+ ea_refcount_free(refcount);
+ return(retval);
+}
+
+/*
+ * collapse_refcount() --- go through the refcount array, and get rid
+ * of any count == zero entries
+ */
+static void refcount_collapse(ext2_refcount_t refcount)
+{
+ unsigned int i, j;
+ struct ea_refcount_el *list;
+
+ list = refcount->list;
+ for (i = 0, j = 0; i < refcount->count; i++) {
+ if (list[i].ea_count) {
+ if (i != j)
+ list[j] = list[i];
+ j++;
+ }
+ }
+#if defined(DEBUG) || defined(TEST_PROGRAM)
+ printf("Refcount_collapse: size was %d, now %d\n",
+ refcount->count, j);
+#endif
+ refcount->count = j;
+}
+
+
+/*
+ * insert_refcount_el() --- Insert a new entry into the sorted list at a
+ * specified position.
+ */
+static struct ea_refcount_el *insert_refcount_el(ext2_refcount_t refcount,
+ blk_t blk, int pos)
+{
+ struct ea_refcount_el *el;
+ errcode_t retval;
+ blk_t new_size = 0;
+ int num;
+
+ if (refcount->count >= refcount->size) {
+ new_size = refcount->size + 100;
+#ifdef DEBUG
+ printf("Reallocating refcount %d entries...\n", new_size);
+#endif
+ retval = ext2fs_resize_mem((size_t) refcount->size *
+ sizeof(struct ea_refcount_el),
+ (size_t) new_size *
+ sizeof(struct ea_refcount_el),
+ &refcount->list);
+ if (retval)
+ return 0;
+ refcount->size = new_size;
+ }
+ num = (int) refcount->count - pos;
+ if (num < 0)
+ return 0; /* should never happen */
+ if (num) {
+ memmove(&refcount->list[pos+1], &refcount->list[pos],
+ sizeof(struct ea_refcount_el) * num);
+ }
+ refcount->count++;
+ el = &refcount->list[pos];
+ el->ea_count = 0;
+ el->ea_blk = blk;
+ return el;
+}
+
+
+/*
+ * get_refcount_el() --- given an block number, try to find refcount
+ * information in the sorted list. If the create flag is set,
+ * and we can't find an entry, create one in the sorted list.
+ */
+static struct ea_refcount_el *get_refcount_el(ext2_refcount_t refcount,
+ blk_t blk, int create)
+{
+ float range;
+ int low, high, mid;
+ blk_t lowval, highval;
+
+ if (!refcount || !refcount->list)
+ return 0;
+retry:
+ low = 0;
+ high = (int) refcount->count-1;
+ if (create && ((refcount->count == 0) ||
+ (blk > refcount->list[high].ea_blk))) {
+ if (refcount->count >= refcount->size)
+ refcount_collapse(refcount);
+
+ return insert_refcount_el(refcount, blk,
+ (unsigned) refcount->count);
+ }
+ if (refcount->count == 0)
+ return 0;
+
+ if (refcount->cursor >= refcount->count)
+ refcount->cursor = 0;
+ if (blk == refcount->list[refcount->cursor].ea_blk)
+ return &refcount->list[refcount->cursor++];
+#ifdef DEBUG
+ printf("Non-cursor get_refcount_el: %u\n", blk);
+#endif
+ while (low <= high) {
+#if 0
+ mid = (low+high)/2;
+#else
+ if (low == high)
+ mid = low;
+ else {
+ /* Interpolate for efficiency */
+ lowval = refcount->list[low].ea_blk;
+ highval = refcount->list[high].ea_blk;
+
+ if (blk < lowval)
+ range = 0;
+ else if (blk > highval)
+ range = 1;
+ else
+ range = ((float) (blk - lowval)) /
+ (highval - lowval);
+ mid = low + ((int) (range * (high-low)));
+ }
+#endif
+ if (blk == refcount->list[mid].ea_blk) {
+ refcount->cursor = mid+1;
+ return &refcount->list[mid];
+ }
+ if (blk < refcount->list[mid].ea_blk)
+ high = mid-1;
+ else
+ low = mid+1;
+ }
+ /*
+ * If we need to create a new entry, it should be right at
+ * low (where high will be left at low-1).
+ */
+ if (create) {
+ if (refcount->count >= refcount->size) {
+ refcount_collapse(refcount);
+ if (refcount->count < refcount->size)
+ goto retry;
+ }
+ return insert_refcount_el(refcount, blk, low);
+ }
+ return 0;
+}
+
+errcode_t ea_refcount_fetch(ext2_refcount_t refcount, blk_t blk,
+ int *ret)
+{
+ struct ea_refcount_el *el;
+
+ el = get_refcount_el(refcount, blk, 0);
+ if (!el) {
+ *ret = 0;
+ return 0;
+ }
+ *ret = el->ea_count;
+ return 0;
+}
+
+errcode_t ea_refcount_increment(ext2_refcount_t refcount, blk_t blk, int *ret)
+{
+ struct ea_refcount_el *el;
+
+ el = get_refcount_el(refcount, blk, 1);
+ if (!el)
+ return EXT2_ET_NO_MEMORY;
+ el->ea_count++;
+
+ if (ret)
+ *ret = el->ea_count;
+ return 0;
+}
+
+errcode_t ea_refcount_decrement(ext2_refcount_t refcount, blk_t blk, int *ret)
+{
+ struct ea_refcount_el *el;
+
+ el = get_refcount_el(refcount, blk, 0);
+ if (!el || el->ea_count == 0)
+ return EXT2_ET_INVALID_ARGUMENT;
+
+ el->ea_count--;
+
+ if (ret)
+ *ret = el->ea_count;
+ return 0;
+}
+
+errcode_t ea_refcount_store(ext2_refcount_t refcount, blk_t blk, int count)
+{
+ struct ea_refcount_el *el;
+
+ /*
+ * Get the refcount element
+ */
+ el = get_refcount_el(refcount, blk, count ? 1 : 0);
+ if (!el)
+ return count ? EXT2_ET_NO_MEMORY : 0;
+ el->ea_count = count;
+ return 0;
+}
+
+blk_t ext2fs_get_refcount_size(ext2_refcount_t refcount)
+{
+ if (!refcount)
+ return 0;
+
+ return refcount->size;
+}
+
+void ea_refcount_intr_begin(ext2_refcount_t refcount)
+{
+ refcount->cursor = 0;
+}
+
+
+blk_t ea_refcount_intr_next(ext2_refcount_t refcount,
+ int *ret)
+{
+ struct ea_refcount_el *list;
+
+ while (1) {
+ if (refcount->cursor >= refcount->count)
+ return 0;
+ list = refcount->list;
+ if (list[refcount->cursor].ea_count) {
+ if (ret)
+ *ret = list[refcount->cursor].ea_count;
+ return list[refcount->cursor++].ea_blk;
+ }
+ refcount->cursor++;
+ }
+}
+
+
+#ifdef TEST_PROGRAM
+
+errcode_t ea_refcount_validate(ext2_refcount_t refcount, FILE *out)
+{
+ errcode_t ret = 0;
+ int i;
+ const char *bad = "bad refcount";
+
+ if (refcount->count > refcount->size) {
+ fprintf(out, "%s: count > size\n", bad);
+ return EXT2_ET_INVALID_ARGUMENT;
+ }
+ for (i=1; i < refcount->count; i++) {
+ if (refcount->list[i-1].ea_blk >= refcount->list[i].ea_blk) {
+ fprintf(out, "%s: list[%d].blk=%u, list[%d].blk=%u\n",
+ bad, i-1, refcount->list[i-1].ea_blk,
+ i, refcount->list[i].ea_blk);
+ ret = EXT2_ET_INVALID_ARGUMENT;
+ }
+ }
+ return ret;
+}
+
+#define BCODE_END 0
+#define BCODE_CREATE 1
+#define BCODE_FREE 2
+#define BCODE_STORE 3
+#define BCODE_INCR 4
+#define BCODE_DECR 5
+#define BCODE_FETCH 6
+#define BCODE_VALIDATE 7
+#define BCODE_LIST 8
+#define BCODE_COLLAPSE 9
+
+int bcode_program[] = {
+ BCODE_CREATE, 5,
+ BCODE_STORE, 3, 3,
+ BCODE_STORE, 4, 4,
+ BCODE_STORE, 1, 1,
+ BCODE_STORE, 8, 8,
+ BCODE_STORE, 2, 2,
+ BCODE_STORE, 4, 0,
+ BCODE_STORE, 2, 0,
+ BCODE_STORE, 6, 6,
+ BCODE_VALIDATE,
+ BCODE_STORE, 4, 4,
+ BCODE_STORE, 2, 2,
+ BCODE_FETCH, 1,
+ BCODE_FETCH, 2,
+ BCODE_INCR, 3,
+ BCODE_INCR, 3,
+ BCODE_DECR, 4,
+ BCODE_STORE, 4, 4,
+ BCODE_VALIDATE,
+ BCODE_STORE, 20, 20,
+ BCODE_STORE, 40, 40,
+ BCODE_STORE, 30, 30,
+ BCODE_STORE, 10, 10,
+ BCODE_DECR, 30,
+ BCODE_FETCH, 30,
+ BCODE_DECR, 2,
+ BCODE_DECR, 2,
+ BCODE_COLLAPSE,
+ BCODE_LIST,
+ BCODE_VALIDATE,
+ BCODE_FREE,
+ BCODE_END
+};
+
+int main(int argc, char **argv)
+{
+ int i = 0;
+ ext2_refcount_t refcount;
+ int size, arg;
+ blk_t blk;
+ errcode_t retval;
+
+ while (1) {
+ switch (bcode_program[i++]) {
+ case BCODE_END:
+ exit(0);
+ case BCODE_CREATE:
+ size = bcode_program[i++];
+ retval = ea_refcount_create(size, &refcount);
+ if (retval) {
+ com_err("ea_refcount_create",
+ retval, "");
+ exit(1);
+ } else
+ printf("Creating refcount with size %d\n",
+ size);
+ break;
+ case BCODE_FREE:
+ ea_refcount_free(refcount);
+ refcount = 0;
+ printf("Freeing refcount\n");
+ break;
+ case BCODE_STORE:
+ blk = (blk_t) bcode_program[i++];
+ arg = bcode_program[i++];
+ retval = ea_refcount_store(refcount, blk, arg);
+ printf("Storing blk %u with value %d\n", blk, arg);
+ if (retval)
+ com_err("ea_refcount_store", retval, "");
+ break;
+ case BCODE_FETCH:
+ blk = (blk_t) bcode_program[i++];
+ retval = ea_refcount_fetch(refcount, blk, &arg);
+ if (retval)
+ com_err("ea_refcount_fetch", retval, "");
+ else
+ printf("bcode_fetch(%u) returns %d\n",
+ blk, arg);
+ break;
+ case BCODE_INCR:
+ blk = (blk_t) bcode_program[i++];
+ retval = ea_refcount_increment(refcount, blk,
+ &arg);
+ if (retval)
+ com_err("ea_refcount_increment", retval,
+ "");
+ else
+ printf("bcode_increment(%u) returns %d\n",
+ blk, arg);
+ break;
+ case BCODE_DECR:
+ blk = (blk_t) bcode_program[i++];
+ retval = ea_refcount_decrement(refcount, blk,
+ &arg);
+ if (retval)
+ com_err("ea_refcount_decrement", retval,
+ "while decrementing blk %u", blk);
+ else
+ printf("bcode_decrement(%u) returns %d\n",
+ blk, arg);
+ break;
+ case BCODE_VALIDATE:
+ retval = ea_refcount_validate(refcount, stderr);
+ if (retval)
+ com_err("ea_refcount_validate",
+ retval, "");
+ else
+ printf("Refcount validation OK.\n");
+ break;
+ case BCODE_LIST:
+ ea_refcount_intr_begin(refcount);
+ while (1) {
+ blk = ea_refcount_intr_next(refcount,
+ &arg);
+ if (!blk)
+ break;
+ printf("\tblk=%u, count=%d\n", blk,
+ arg);
+ }
+ break;
+ case BCODE_COLLAPSE:
+ refcount_collapse(refcount);
+ break;
+ }
+
+ }
+}
+
+#endif
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