NeilBrown <neilb@xxxxxxx> writes:
> This can show the log (providing it fits in one page) and
> allows bad blocks to be 'acknowledged' meaning that they
> have safely been recorded in metadata.
>
> Clearing bad blocks is not allowed via sysfs (except for
> code testing). A bad block can only be cleared when
> a write to the block succeeds.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
>
> drivers/md/md.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 127 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 220fadb..9324635 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2712,6 +2712,35 @@ static ssize_t recovery_start_store(mdk_rdev_t *rdev, const char *buf, size_t le
> static struct rdev_sysfs_entry rdev_recovery_start =
> __ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);
>
> +
> +static ssize_t
> +badblocks_show(struct badblocks *bb, char *page, int unack);
> +static ssize_t
> +badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack);
> +
> +static ssize_t bb_show(mdk_rdev_t *rdev, char *page)
> +{
> + return badblocks_show(&rdev->badblocks, page, 0);
> +}
> +static ssize_t bb_store(mdk_rdev_t *rdev, const char *page, size_t len)
> +{
> + return badblocks_store(&rdev->badblocks, page, len, 0);
> +}
> +static struct rdev_sysfs_entry rdev_bad_blocks =
> +__ATTR(bad_blocks, S_IRUGO|S_IWUSR, bb_show, bb_store);
> +
> +
> +static ssize_t ubb_show(mdk_rdev_t *rdev, char *page)
> +{
> + return badblocks_show(&rdev->badblocks, page, 1);
> +}
> +static ssize_t ubb_store(mdk_rdev_t *rdev, const char *page, size_t len)
> +{
> + return badblocks_store(&rdev->badblocks, page, len, 1);
> +}
> +static struct rdev_sysfs_entry rdev_unack_bad_blocks =
> +__ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);
> +
> static struct attribute *rdev_default_attrs[] = {
> &rdev_state.attr,
> &rdev_errors.attr,
> @@ -2719,6 +2748,8 @@ static struct attribute *rdev_default_attrs[] = {
> &rdev_offset.attr,
> &rdev_size.attr,
> &rdev_recovery_start.attr,
> + &rdev_bad_blocks.attr,
> + &rdev_unack_bad_blocks.attr,
> NULL,
> };
> static ssize_t
> @@ -7775,6 +7806,102 @@ void md_ack_all_badblocks(struct badblocks *bb)
> }
> EXPORT_SYMBOL_GPL(md_ack_all_badblocks);
>
> +/* sysfs access to bad-blocks list.
> + * We present two files.
> + * 'bad-blocks' lists sector numbers and lengths of ranges that
> + * are recorded as bad. The list is truncated to fit within
> + * the one-page limit of sysfs.
> + * Writing "sector length" to this file adds an acknowledged
> + * bad block list.
> + * 'unacknowledged-bad-blocks' lists bad blocks that have not yet
> + * been acknowledged. Writing to this file adds bad blocks
> + * without acknowledging them. This is largely for testing.
> + *
> + */
> +
> +static ssize_t
> +badblocks_show(struct badblocks *bb, char *page, int unack)
> +{
> + size_t len = 0;
> + int i;
> + u64 *p;
> + int havelock = 0;
> +
> + if (bb->shift < 0)
> + return 0;
> +
> + rcu_read_lock();
> + p = rcu_dereference(bb->active_page);
> + if (!p) {
> + spin_lock_irq(&bb->lock);
> + p = bb->page;
> + havelock = 1;
> + }
> +
> + i = 0;
> +
> + while (len < PAGE_SIZE && i < bb->count) {
> + sector_t s = BB_OFFSET(p[i]);
> + unsigned int length = BB_LEN(p[i]);
> + int ack = BB_ACK(p[i]);
> + i++;
> +
> + if (unack && ack)
> + continue;
> +
> + len += snprintf(page+len, PAGE_SIZE-len, "%llu %u\n",
> + (unsigned long long)s << bb->shift,
> + length << bb->shift);
> + }
> +
> + if (havelock)
> + spin_unlock_irq(&bb->lock);
> + rcu_read_unlock();
> +
> + return len;
> +}
> +
> +#define DO_DEBUG 1
> +
> +static ssize_t
> +badblocks_store(struct badblocks *bb, const char *page, size_t len, int unack)
> +{
> + unsigned long long sector;
> + int length;
> + char newline;
> +#ifdef DO_DEBUG
> + /* Allow clearing via sysfs *only* for testing/debugging.
> + * Normally only a successful write may clear a badblock
> + */
> + int clear = 0;
> + if (page[0] == '-') {
> + clear = 1;
> + page++;
> + }
> +#endif /* DO_DEBUG */
> +
> + switch (sscanf(page, "%llu %d%c", §or, &length, &newline)) {
What if user provides negative 'length' here? Should we check that case?
> + case 3:
> + if (newline != '\n')
> + return -EINVAL;
> + case 2:
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> +#ifdef DO_DEBUG
> + if (clear) {
> + md_clear_badblocks(bb, sector, length);
> + return len;
> + }
> +#endif /* DO_DEBUG */
> + if (md_set_badblocks(bb, sector, length, !unack))
> + return len;
> + else
> + return -ENOSPC;
> +}
> +
> static int md_notify_reboot(struct notifier_block *this,
> unsigned long code, void *x)
> {
>
>
> --
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