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dm dust: add limited write failure mode

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Add a limited write failure mode which allows a write to a block to fail
a specified amount of times, prior to remapping.  The "addbadblock"
message is extended to allow specifying the limited number of times a
write fails.

Example: add bad block on block 60, with 5 write failures:
  dmsetup message 0 dust1 addbadblock 60 5

The write failure counter will be printed for newly added bad blocks.

Signed-off-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Bryan Gurney 2019-10-22 16:46:01 -04:00 committed by Mike Snitzer
parent cc7a7fb3b6
commit 72d7df4c80
1 changed files with 46 additions and 7 deletions
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53
drivers/md/dm-dust.c
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@ -17,6 +17,7 @@
struct badblock {
struct rb_node node;
sector_t bb;
unsigned char wr_fail_cnt;
};
struct dust_device {
@ -101,7 +102,8 @@ static int dust_remove_block(struct dust_device *dd, unsigned long long block)
return 0;
}
static int dust_add_block(struct dust_device *dd, unsigned long long block)
static int dust_add_block(struct dust_device *dd, unsigned long long block,
unsigned char wr_fail_cnt)
{
struct badblock *bblock;
unsigned long flags;
@ -115,6 +117,7 @@ static int dust_add_block(struct dust_device *dd, unsigned long long block)
spin_lock_irqsave(&dd->dust_lock, flags);
bblock->bb = block;
bblock->wr_fail_cnt = wr_fail_cnt;
if (!dust_rb_insert(&dd->badblocklist, bblock)) {
if (!dd->quiet_mode) {
DMERR("%s: block %llu already in badblocklist",
@ -126,8 +129,10 @@ static int dust_add_block(struct dust_device *dd, unsigned long long block)
}
dd->badblock_count++;
if (!dd->quiet_mode)
DMINFO("%s: badblock added at block %llu", __func__, block);
if (!dd->quiet_mode) {
DMINFO("%s: badblock added at block %llu with write fail count %hhu",
__func__, block, wr_fail_cnt);
}
spin_unlock_irqrestore(&dd->dust_lock, flags);
return 0;
@ -175,10 +180,15 @@ static int dust_map_read(struct dust_device *dd, sector_t thisblock,
return r;
}
static void __dust_map_write(struct dust_device *dd, sector_t thisblock)
static int __dust_map_write(struct dust_device *dd, sector_t thisblock)
{
struct badblock *bblk = dust_rb_search(&dd->badblocklist, thisblock);
if (bblk && bblk->wr_fail_cnt > 0) {
bblk->wr_fail_cnt--;
return DM_MAPIO_KILL;
}
if (bblk) {
rb_erase(&bblk->node, &dd->badblocklist);
dd->badblock_count--;
@ -189,21 +199,24 @@ static void __dust_map_write(struct dust_device *dd, sector_t thisblock)
(unsigned long long)thisblock);
}
}
return DM_MAPIO_REMAPPED;
}
static int dust_map_write(struct dust_device *dd, sector_t thisblock,
bool fail_read_on_bb)
{
unsigned long flags;
int ret = DM_MAPIO_REMAPPED;
if (fail_read_on_bb) {
thisblock >>= dd->sect_per_block_shift;
spin_lock_irqsave(&dd->dust_lock, flags);
__dust_map_write(dd, thisblock);
ret = __dust_map_write(dd, thisblock);
spin_unlock_irqrestore(&dd->dust_lock, flags);
}
return DM_MAPIO_REMAPPED;
return ret;
}
static int dust_map(struct dm_target *ti, struct bio *bio)
@ -377,6 +390,8 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
bool invalid_msg = false;
int r = -EINVAL;
unsigned long long tmp, block;
unsigned char wr_fail_cnt;
unsigned int tmp_ui;
unsigned long flags;
char dummy;
@ -422,7 +437,7 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
}
if (!strcasecmp(argv[0], "addbadblock"))
r = dust_add_block(dd, block);
r = dust_add_block(dd, block, 0);
else if (!strcasecmp(argv[0], "removebadblock"))
r = dust_remove_block(dd, block);
else if (!strcasecmp(argv[0], "queryblock"))
@ -430,6 +445,30 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv,
else
invalid_msg = true;
} else if (argc == 3) {
if (sscanf(argv[1], "%llu%c", &tmp, &dummy) != 1)
return r;
if (sscanf(argv[2], "%u%c", &tmp_ui, &dummy) != 1)
return r;
block = tmp;
if (tmp_ui > 255) {
DMERR("selected write fail count out of range");
return r;
}
wr_fail_cnt = tmp_ui;
sector_div(size, dd->sect_per_block);
if (block > size) {
DMERR("selected block value out of range");
return r;
}
if (!strcasecmp(argv[0], "addbadblock"))
r = dust_add_block(dd, block, wr_fail_cnt);
else
invalid_msg = true;
} else
DMERR("invalid number of arguments '%d'", argc);