I applied this patch(set) but I couldn't create any mirror devices with
"handle_errors" feature because the following code assumes that the
device list is the last to be given.
mirror_ctr()
{
....
if (argc != nr_mirrors * 2) {
ti->error = "Wrong number of mirror arguments";
dm_destroy_dirty_log(dl);
return -EINVAL;
}
}
Changing the condition to "(argc < nr_mirrors * 2)" worked fine. Anyone else
using this patch? Are there any updates to this patch set?
Thanks, Malahal.
Jonathan Brassow [jbrassow@xxxxxxxxxx] wrote:
> 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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