1 files changed, 476 insertions, 0 deletions

diff --git a/e2fsck/ea_refcount.c b/e2fsck/ea_refcount.c
new file mode 100644
index 0000000..7154b47
--- /dev/null
+++ b/e2fsck/ea_refcount.c
@@ -0,0 +1,476 @@
+/*
+ * ea_refcount.c
+ *
+ * Copyright (C) 2001 Theodore Ts'o.  This file may be
+ * redistributed under the terms of the GNU Public License.
+ */
+
+#include "config.h"
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <string.h>
+#include <stdio.h>
+
+#ifdef TEST_PROGRAM
+#undef ENABLE_NLS
+#endif
+#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 {
+	/* ea_key could either be an inode number or block number. */
+	ea_key_t	ea_key;
+	ea_value_t	ea_value;
+};
+
+struct ea_refcount {
+	size_t		count;
+	size_t		size;
+	size_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(size_t size, ext2_refcount_t *ret)
+{
+	ext2_refcount_t	refcount;
+	errcode_t	retval;
+	size_t		bytes;
+
+	retval = ext2fs_get_memzero(sizeof(struct ea_refcount), &refcount);
+	if (retval)
+		return retval;
+
+	if (!size)
+		size = 500;
+	refcount->size = size;
+	bytes = size * sizeof(struct ea_refcount_el);
+#ifdef DEBUG
+	printf("Refcount allocated %zu entries, %zu bytes.\n",
+	       refcount->size, bytes);
+#endif
+	retval = ext2fs_get_memzero(bytes, &refcount->list);
+	if (retval)
+		goto errout;
+
+	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_value) {
+			if (i != j)
+				list[j] = list[i];
+			j++;
+		}
+	}
+#if defined(DEBUG) || defined(TEST_PROGRAM)
+	printf("Refcount_collapse: size was %zu, 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,
+						 ea_key_t ea_key, int pos)
+{
+	struct ea_refcount_el 	*el;
+	errcode_t		retval;
+	size_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_key = ea_key;
+	el->ea_value = 0;
+	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,
+					      ea_key_t ea_key, int create)
+{
+	int	low, high, mid;
+
+	if (!refcount || !refcount->list)
+		return 0;
+retry:
+	low = 0;
+	high = (int) refcount->count-1;
+	if (create && ((refcount->count == 0) ||
+		       (ea_key > refcount->list[high].ea_key))) {
+		if (refcount->count >= refcount->size)
+			refcount_collapse(refcount);
+
+		return insert_refcount_el(refcount, ea_key,
+					  (unsigned) refcount->count);
+	}
+	if (refcount->count == 0)
+		return 0;
+
+	if (refcount->cursor >= refcount->count)
+		refcount->cursor = 0;
+	if (ea_key == refcount->list[refcount->cursor].ea_key)
+		return &refcount->list[refcount->cursor++];
+#ifdef DEBUG
+	printf("Non-cursor get_refcount_el: %u\n", ea_key);
+#endif
+	while (low <= high) {
+		mid = (low+high)/2;
+		if (ea_key == refcount->list[mid].ea_key) {
+			refcount->cursor = mid+1;
+			return &refcount->list[mid];
+		}
+		if (ea_key < refcount->list[mid].ea_key)
+			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, ea_key, low);
+	}
+	return 0;
+}
+
+errcode_t ea_refcount_fetch(ext2_refcount_t refcount, ea_key_t ea_key,
+			    ea_value_t *ret)
+{
+	struct ea_refcount_el	*el;
+
+	el = get_refcount_el(refcount, ea_key, 0);
+	if (!el) {
+		*ret = 0;
+		return 0;
+	}
+	*ret = el->ea_value;
+	return 0;
+}
+
+errcode_t ea_refcount_increment(ext2_refcount_t refcount, ea_key_t ea_key,
+				ea_value_t *ret)
+{
+	struct ea_refcount_el	*el;
+
+	el = get_refcount_el(refcount, ea_key, 1);
+	if (!el)
+		return EXT2_ET_NO_MEMORY;
+	el->ea_value++;
+
+	if (ret)
+		*ret = el->ea_value;
+	return 0;
+}
+
+errcode_t ea_refcount_decrement(ext2_refcount_t refcount, ea_key_t ea_key,
+				ea_value_t *ret)
+{
+	struct ea_refcount_el	*el;
+
+	el = get_refcount_el(refcount, ea_key, 0);
+	if (!el || el->ea_value == 0)
+		return EXT2_ET_INVALID_ARGUMENT;
+
+	el->ea_value--;
+
+	if (ret)
+		*ret = el->ea_value;
+	return 0;
+}
+
+errcode_t ea_refcount_store(ext2_refcount_t refcount, ea_key_t ea_key,
+			    ea_value_t ea_value)
+{
+	struct ea_refcount_el	*el;
+
+	/*
+	 * Get the refcount element
+	 */
+	el = get_refcount_el(refcount, ea_key, ea_value ? 1 : 0);
+	if (!el)
+		return ea_value ? EXT2_ET_NO_MEMORY : 0;
+	el->ea_value = ea_value;
+	return 0;
+}
+
+size_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;
+}
+
+ea_key_t ea_refcount_intr_next(ext2_refcount_t refcount,
+				ea_value_t *ret)
+{
+	struct ea_refcount_el	*list;
+
+	while (1) {
+		if (refcount->cursor >= refcount->count)
+			return 0;
+		list = refcount->list;
+		if (list[refcount->cursor].ea_value) {
+			if (ret)
+				*ret = list[refcount->cursor].ea_value;
+			return list[refcount->cursor++].ea_key;
+		}
+		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_key >= refcount->list[i].ea_key) {
+			fprintf(out,
+				"%s: list[%d].ea_key=%llu, list[%d].ea_key=%llu\n",
+				bad, i-1,
+				(unsigned long long) refcount->list[i-1].ea_key,
+				i,
+				(unsigned long long) refcount->list[i].ea_key);
+			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;
+	size_t		size;
+	ea_key_t	ea_key;
+	ea_value_t	arg;
+	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,
+					"while creating size %zu", size);
+				exit(1);
+			} else
+				printf("Creating refcount with size %zu\n",
+				       size);
+			break;
+		case BCODE_FREE:
+			ea_refcount_free(refcount);
+			refcount = 0;
+			printf("Freeing refcount\n");
+			break;
+		case BCODE_STORE:
+			ea_key = (size_t) bcode_program[i++];
+			arg = bcode_program[i++];
+			printf("Storing ea_key %llu with value %llu\n",
+			       (unsigned long long) ea_key,
+			       (unsigned long long) arg);
+			retval = ea_refcount_store(refcount, ea_key, arg);
+			if (retval)
+				com_err("ea_refcount_store", retval,
+					"while storing ea_key %llu",
+					(unsigned long long) ea_key);
+			break;
+		case BCODE_FETCH:
+			ea_key = (size_t) bcode_program[i++];
+			retval = ea_refcount_fetch(refcount, ea_key, &arg);
+			if (retval)
+				com_err("ea_refcount_fetch", retval,
+					"while fetching ea_key %llu",
+					(unsigned long long) ea_key);
+			else
+				printf("bcode_fetch(%llu) returns %llu\n",
+				       (unsigned long long) ea_key,
+				       (unsigned long long) arg);
+			break;
+		case BCODE_INCR:
+			ea_key = (size_t) bcode_program[i++];
+			retval = ea_refcount_increment(refcount, ea_key, &arg);
+			if (retval)
+				com_err("ea_refcount_increment", retval,
+					"while incrementing ea_key %llu",
+					(unsigned long long) ea_key);
+			else
+				printf("bcode_increment(%llu) returns %llu\n",
+				       (unsigned long long) ea_key,
+				       (unsigned long long) arg);
+			break;
+		case BCODE_DECR:
+			ea_key = (size_t) bcode_program[i++];
+			retval = ea_refcount_decrement(refcount, ea_key, &arg);
+			if (retval)
+				com_err("ea_refcount_decrement", retval,
+					"while decrementing ea_key %llu",
+					(unsigned long long) ea_key);
+			else
+				printf("bcode_decrement(%llu) returns %llu\n",
+				       (unsigned long long) ea_key,
+				       (unsigned long long) arg);
+			break;
+		case BCODE_VALIDATE:
+			retval = ea_refcount_validate(refcount, stderr);
+			if (retval)
+				com_err("ea_refcount_validate", retval,
+					"while validating");
+			else
+				printf("Refcount validation OK.\n");
+			break;
+		case BCODE_LIST:
+			ea_refcount_intr_begin(refcount);
+			while (1) {
+				ea_key = ea_refcount_intr_next(refcount, &arg);
+				if (!ea_key)
+					break;
+				printf("\tea_key=%llu, count=%llu\n",
+				       (unsigned long long) ea_key,
+				       (unsigned long long) arg);
+			}
+			break;
+		case BCODE_COLLAPSE:
+			refcount_collapse(refcount);
+			break;
+		}
+
+	}
+}
+
+#endif