brassow
This patch adds the ability to specify desired features in the mirror
constructor/mapping table.
The first feature of interest is "handle_errors". Currently, mirroring
will ignore any I/O errors from the devices. Subsequent patches will
check for this flag and handle the errors. If flag/feature is not
present, mirror will do nothing - maintaining backwards compatibility.
Index: linux-2.6.18.1/drivers/md/dm-raid1.c
===================================================================
--- linux-2.6.18.1.orig/drivers/md/dm-raid1.c 2006-11-01 14:16:14.000000000 -0600
+++ linux-2.6.18.1/drivers/md/dm-raid1.c 2006-11-01 14:16:15.000000000 -0600
@@ -114,6 +114,8 @@ struct region {
/*-----------------------------------------------------------------
* Mirror set structures.
*---------------------------------------------------------------*/
+#define DM_FEATURE_HANDLE_ERRORS 0x1
+
struct mirror {
atomic_t error_count;
struct dm_dev *dev;
@@ -130,6 +132,9 @@ struct mirror_set {
struct bio_list reads;
struct bio_list writes;
+ /* Features */
+ uint64_t feature_flags;
+
/* recovery */
region_t nr_regions;
int in_sync;
@@ -1037,14 +1042,63 @@ static struct dirty_log *create_dirty_lo
return dl;
}
+static int parse_features(struct mirror_set *ms,
+ unsigned int argc, char **argv,
+ unsigned int *args_used)
+{
+ int i;
+ unsigned int features_argc, used = 0;
+ struct dm_target *ti = ms->ti;
+
+ *args_used = 0;
+
+ if (!argc)
+ return 0;
+
+ if (sscanf(argv[0], "%u", &features_argc) != 1) {
+ ti->error = "Invalid number of features";
+ return -EINVAL;
+ }
+
+ argc--;
+ argv++;
+ used++;
+
+ if (features_argc > argc) {
+ ti->error = "Not enough arguments to support feature count";
+ return -EINVAL;
+ }
+
+ for (i = 0; i < features_argc; i++) {
+ if (!strcmp("handle_errors", argv[i]))
+ ms->feature_flags |= DM_FEATURE_HANDLE_ERRORS;
+ else {
+ ti->error = "Unknown feature argument";
+ return -EINVAL;
+ }
+ used++;
+ }
+
+ *args_used = used;
+ return 0;
+}
+
/*
- * Construct a mirror mapping:
+ * mirror_ctr
+ * @ti
+ * @argc
+ * @argv
*
- * log_type #log_params <log_params>
- * #mirrors [mirror_path offset]{2,}
+ * Allowable argument list is as follows:
+ * log_type #log_params <log_params> \
+ * #mirrors <device1> <offset1> ... <deviceN> <offsetN> \
+ * <# feature args> <feature args>
*
- * log_type is "core" or "disk"
- * #log_params is between 1 and 3
+ * Refer to log implementation for log specific parameters.
+ * Current features include:
+ * handle_errors
+ *
+ * Returns: 0 on success, -EXXX on failure
*/
#define DM_IO_PAGES 64
static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
@@ -1096,6 +1150,22 @@ static int mirror_ctr(struct dm_target *
ti->private = ms;
ti->split_io = ms->rh.region_size;
+ /* check for features */
+ r = parse_features(ms, argc, argv, &args_used);
+ if (r) {
+ free_context(ms, ti, ms->nr_mirrors);
+ return r;
+ }
+
+ argv += args_used;
+ argc -= args_used;
+
+ if (argc) {
+ ti->error = "Wrong number of mirror arguments";
+ free_context(ms, ti, ms->nr_mirrors);
+ return -EINVAL;
+ }
+
r = kcopyd_client_create(DM_IO_PAGES, &ms->kcopyd_client);
if (r) {
free_context(ms, ti, ms->nr_mirrors);
@@ -1243,6 +1313,9 @@ static int mirror_status(struct dm_targe
for (m = 0; m < ms->nr_mirrors; m++)
DMEMIT(" %s %llu", ms->mirror[m].dev->name,
(unsigned long long)ms->mirror[m].offset);
+
+ if (ms->feature_flags & DM_FEATURE_HANDLE_ERRORS)
+ DMEMIT(" 1 handle_errors");
}
return 0;
--
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