--- /dev/null
+/*
+ * QEMU Enhanced Disk Format Consistency Check
+ *
+ * Copyright IBM, Corp. 2010
+ *
+ * Authors:
+ * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qed.h"
+
+typedef struct {
+ BDRVQEDState *s;
+ BdrvCheckResult *result;
+ bool fix; /* whether to fix invalid offsets */
+
+ uint64_t nclusters;
+ uint32_t *used_clusters; /* referenced cluster bitmap */
+
+ QEDRequest request;
+} QEDCheck;
+
+static bool qed_test_bit(uint32_t *bitmap, uint64_t n) {
+ return !!(bitmap[n / 32] & (1 << (n % 32)));
+}
+
+static void qed_set_bit(uint32_t *bitmap, uint64_t n) {
+ bitmap[n / 32] |= 1 << (n % 32);
+}
+
+/**
+ * Set bitmap bits for clusters
+ *
+ * @check: Check structure
+ * @offset: Starting offset in bytes
+ * @n: Number of clusters
+ */
+static bool qed_set_used_clusters(QEDCheck *check, uint64_t offset,
+ unsigned int n)
+{
+ uint64_t cluster = qed_bytes_to_clusters(check->s, offset);
+ unsigned int corruptions = 0;
+
+ while (n-- != 0) {
+ /* Clusters should only be referenced once */
+ if (qed_test_bit(check->used_clusters, cluster)) {
+ corruptions++;
+ }
+
+ qed_set_bit(check->used_clusters, cluster);
+ cluster++;
+ }
+
+ check->result->corruptions += corruptions;
+ return corruptions == 0;
+}
+
+/**
+ * Check an L2 table
+ *
+ * @ret: Number of invalid cluster offsets
+ */
+static unsigned int qed_check_l2_table(QEDCheck *check, QEDTable *table)
+{
+ BDRVQEDState *s = check->s;
+ unsigned int i, num_invalid = 0;
+ uint64_t last_offset = 0;
+
+ for (i = 0; i < s->table_nelems; i++) {
+ uint64_t offset = table->offsets[i];
+
+ if (qed_offset_is_unalloc_cluster(offset) ||
+ qed_offset_is_zero_cluster(offset)) {
+ continue;
+ }
+ check->result->bfi.allocated_clusters++;
+ if (last_offset && (last_offset + s->header.cluster_size != offset)) {
+ check->result->bfi.fragmented_clusters++;
+ }
+ last_offset = offset;
+
+ /* Detect invalid cluster offset */
+ if (!qed_check_cluster_offset(s, offset)) {
+ if (check->fix) {
+ table->offsets[i] = 0;
+ check->result->corruptions_fixed++;
+ } else {
+ check->result->corruptions++;
+ }
+
+ num_invalid++;
+ continue;
+ }
+
+ qed_set_used_clusters(check, offset, 1);
+ }
+
+ return num_invalid;
+}
+
+/**
+ * Descend tables and check each cluster is referenced once only
+ */
+static int qed_check_l1_table(QEDCheck *check, QEDTable *table)
+{
+ BDRVQEDState *s = check->s;
+ unsigned int i, num_invalid_l1 = 0;
+ int ret, last_error = 0;
+
+ /* Mark L1 table clusters used */
+ qed_set_used_clusters(check, s->header.l1_table_offset,
+ s->header.table_size);
+
+ for (i = 0; i < s->table_nelems; i++) {
+ unsigned int num_invalid_l2;
+ uint64_t offset = table->offsets[i];
+
+ if (qed_offset_is_unalloc_cluster(offset)) {
+ continue;
+ }
+
+ /* Detect invalid L2 offset */
+ if (!qed_check_table_offset(s, offset)) {
+ /* Clear invalid offset */
+ if (check->fix) {
+ table->offsets[i] = 0;
+ check->result->corruptions_fixed++;
+ } else {
+ check->result->corruptions++;
+ }
+
+ num_invalid_l1++;
+ continue;
+ }
+
+ if (!qed_set_used_clusters(check, offset, s->header.table_size)) {
+ continue; /* skip an invalid table */
+ }
+
+ ret = qed_read_l2_table_sync(s, &check->request, offset);
+ if (ret) {
+ check->result->check_errors++;
+ last_error = ret;
+ continue;
+ }
+
+ num_invalid_l2 = qed_check_l2_table(check,
+ check->request.l2_table->table);
+
+ /* Write out fixed L2 table */
+ if (num_invalid_l2 > 0 && check->fix) {
+ ret = qed_write_l2_table_sync(s, &check->request, 0,
+ s->table_nelems, false);
+ if (ret) {
+ check->result->check_errors++;
+ last_error = ret;
+ continue;
+ }
+ }
+ }
+
+ /* Drop reference to final table */
+ qed_unref_l2_cache_entry(check->request.l2_table);
+ check->request.l2_table = NULL;
+
+ /* Write out fixed L1 table */
+ if (num_invalid_l1 > 0 && check->fix) {
+ ret = qed_write_l1_table_sync(s, 0, s->table_nelems);
+ if (ret) {
+ check->result->check_errors++;
+ last_error = ret;
+ }
+ }
+
+ return last_error;
+}
+
+/**
+ * Check for unreferenced (leaked) clusters
+ */
+static void qed_check_for_leaks(QEDCheck *check)
+{
+ BDRVQEDState *s = check->s;
+ uint64_t i;
+
+ for (i = s->header.header_size; i < check->nclusters; i++) {
+ if (!qed_test_bit(check->used_clusters, i)) {
+ check->result->leaks++;
+ }
+ }
+}
+
+/**
+ * Mark an image clean once it passes check or has been repaired
+ */
+static void qed_check_mark_clean(BDRVQEDState *s, BdrvCheckResult *result)
+{
+ /* Skip if there were unfixable corruptions or I/O errors */
+ if (result->corruptions > 0 || result->check_errors > 0) {
+ return;
+ }
+
+ /* Skip if image is already marked clean */
+ if (!(s->header.features & QED_F_NEED_CHECK)) {
+ return;
+ }
+
+ /* Ensure fixes reach storage before clearing check bit */
+ bdrv_flush(s->bs);
+
+ s->header.features &= ~QED_F_NEED_CHECK;
+ qed_write_header_sync(s);
+}
+
+int qed_check(BDRVQEDState *s, BdrvCheckResult *result, bool fix)
+{
+ QEDCheck check = {
+ .s = s,
+ .result = result,
+ .nclusters = qed_bytes_to_clusters(s, s->file_size),
+ .request = { .l2_table = NULL },
+ .fix = fix,
+ };
+ int ret;
+
+ check.used_clusters = g_try_new0(uint32_t, (check.nclusters + 31) / 32);
+ if (check.nclusters && check.used_clusters == NULL) {
+ return -ENOMEM;
+ }
+
+ check.result->bfi.total_clusters =
+ (s->header.image_size + s->header.cluster_size - 1) /
+ s->header.cluster_size;
+ ret = qed_check_l1_table(&check, s->l1_table);
+ if (ret == 0) {
+ /* Only check for leaks if entire image was scanned successfully */
+ qed_check_for_leaks(&check);
+
+ if (fix) {
+ qed_check_mark_clean(s, result);
+ }
+ }
+
+ g_free(check.used_clusters);
+ return ret;
+}
Code Review / kvmfornfv.git / blobdiff