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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 08-02-2011, 02:36 PM
Joe Thornber
 
Default Track errored blocks

i) Keep track of how many blocks are in the error state.

ii) Make the client pass in the max number of held locks by a thread
at any one time.

iii) Change recycle_block to give up if there are too many in error
state.
---
drivers/md/dm-thin-metadata.c | 2 +-
drivers/md/persistent-data/dm-block-manager.c | 24 +++++++++++++++++++++---
drivers/md/persistent-data/dm-block-manager.h | 9 ++++++++-
3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index f3b8825..4c9470a 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -561,7 +561,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
int create;

bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
- THIN_METADATA_CACHE_SIZE);
+ THIN_METADATA_CACHE_SIZE, 3);
if (!bm) {
DMERR("could not create block manager");
return ERR_PTR(-ENOMEM);
diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
index d27ab6e..dd22ef2 100644
--- a/drivers/md/persistent-data/dm-block-manager.c
+++ b/drivers/md/persistent-data/dm-block-manager.c
@@ -58,7 +58,8 @@ struct dm_block {

struct dm_block_manager {
struct block_device *bdev;
- unsigned cache_size; /* In bytes */
+ unsigned cache_size;
+ unsigned max_held_per_thread;
unsigned block_size; /* In bytes */
dm_block_t nr_blocks;

@@ -74,6 +75,7 @@ struct dm_block_manager {
*/
spinlock_t lock;

+ unsigned error_count;
unsigned available_count;
unsigned reading_count;
unsigned writing_count;
@@ -161,8 +163,10 @@ static void __transition(struct dm_block *b, enum dm_block_state new_state)
b->io_flags = 0;
b->validator = NULL;

- if (b->state == BS_ERROR)
+ if (b->state == BS_ERROR) {
+ bm->error_count--;
bm->available_count++;
+ }
break;

case BS_CLEAN:
@@ -244,6 +248,7 @@ static void __transition(struct dm_block *b, enum dm_block_state new_state)
/* DOT: reading -> error */
BUG_ON(!((b->state == BS_WRITING) ||
(b->state == BS_READING)));
+ bm->error_count++;
list_add_tail(&b->list, &bm->error_list);
break;
}
@@ -450,6 +455,16 @@ static int recycle_block(struct dm_block_manager *bm, dm_block_t where,
retry:
while (1) {
/*
+ * The calling thread may hold some locks on blocks, and
+ * the rest be errored. In which case we're never going to
+ * succeed here.
+ */
+ if (bm->error_count == bm->cache_size - bm->max_held_per_thread) {
+ spin_unlock_irqrestore(&bm->lock, flags);
+ return -ENOMEM;
+ }
+
+ /*
* Once we can lock and do io concurrently then we should
* probably flush at bm->cache_size / 2 and write _all_
* dirty blocks.
@@ -599,7 +614,8 @@ static unsigned calc_hash_size(unsigned cache_size)

struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
unsigned block_size,
- unsigned cache_size)
+ unsigned cache_size,
+ unsigned max_held_per_thread)
{
unsigned i;
unsigned hash_size = calc_hash_size(cache_size);
@@ -613,6 +629,7 @@ struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,

bm->bdev = bdev;
bm->cache_size = max(MAX_CACHE_SIZE, cache_size);
+ bm->max_held_per_thread = max_held_per_thread;
bm->block_size = block_size;
bm->nr_blocks = i_size_read(bdev->bd_inode);
do_div(bm->nr_blocks, block_size);
@@ -623,6 +640,7 @@ struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
INIT_LIST_HEAD(&bm->clean_list);
INIT_LIST_HEAD(&bm->dirty_list);
INIT_LIST_HEAD(&bm->error_list);
+ bm->error_count = 0;
bm->available_count = 0;
bm->reading_count = 0;
bm->writing_count = 0;
diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h
index ebea2d5..38c49c7 100644
--- a/drivers/md/persistent-data/dm-block-manager.h
+++ b/drivers/md/persistent-data/dm-block-manager.h
@@ -37,7 +37,14 @@ static inline uint32_t dm_block_csum_data(const void *data_le, unsigned length)
/*----------------------------------------------------------------*/

struct dm_block_manager;
-struct dm_block_manager *dm_block_manager_create(struct block_device *bdev, unsigned block_size, unsigned cache_size);
+
+/*
+ * @max_held_per_thread should be the maximum number of locks, read or
+ * write, that an individual thread holds at any one time.
+ */
+struct dm_block_manager *dm_block_manager_create(
+ struct block_device *bdev, unsigned block_size,
+ unsigned cache_size, unsigned max_held_per_thread);
void dm_block_manager_destroy(struct dm_block_manager *bm);

unsigned dm_bm_block_size(struct dm_block_manager *bm);
--
1.7.4.1

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Old 08-03-2011, 03:00 PM
Mikulas Patocka
 
Default Track errored blocks

Ack.

BTW. I found another quirk in recycle_block:
if (b->state == BS_ERROR) {
__transition(b, BS_EMPTY);
r = -EIO;
}
if (b->validator) {
r = b->validator->check(b->validator, b, bm->block_size);
...
}

--- I think errorneous buffers should not be validated, change it to
"if (!r && b->validator)"

Mikulas

On Tue, 2 Aug 2011, Joe Thornber wrote:

> i) Keep track of how many blocks are in the error state.
>
> ii) Make the client pass in the max number of held locks by a thread
> at any one time.
>
> iii) Change recycle_block to give up if there are too many in error
> state.
> ---
> drivers/md/dm-thin-metadata.c | 2 +-
> drivers/md/persistent-data/dm-block-manager.c | 24 +++++++++++++++++++++---
> drivers/md/persistent-data/dm-block-manager.h | 9 ++++++++-
> 3 files changed, 30 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
> index f3b8825..4c9470a 100644
> --- a/drivers/md/dm-thin-metadata.c
> +++ b/drivers/md/dm-thin-metadata.c
> @@ -561,7 +561,7 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
> int create;
>
> bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
> - THIN_METADATA_CACHE_SIZE);
> + THIN_METADATA_CACHE_SIZE, 3);
> if (!bm) {
> DMERR("could not create block manager");
> return ERR_PTR(-ENOMEM);
> diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
> index d27ab6e..dd22ef2 100644
> --- a/drivers/md/persistent-data/dm-block-manager.c
> +++ b/drivers/md/persistent-data/dm-block-manager.c
> @@ -58,7 +58,8 @@ struct dm_block {
>
> struct dm_block_manager {
> struct block_device *bdev;
> - unsigned cache_size; /* In bytes */
> + unsigned cache_size;
> + unsigned max_held_per_thread;
> unsigned block_size; /* In bytes */
> dm_block_t nr_blocks;
>
> @@ -74,6 +75,7 @@ struct dm_block_manager {
> */
> spinlock_t lock;
>
> + unsigned error_count;
> unsigned available_count;
> unsigned reading_count;
> unsigned writing_count;
> @@ -161,8 +163,10 @@ static void __transition(struct dm_block *b, enum dm_block_state new_state)
> b->io_flags = 0;
> b->validator = NULL;
>
> - if (b->state == BS_ERROR)
> + if (b->state == BS_ERROR) {
> + bm->error_count--;
> bm->available_count++;
> + }
> break;
>
> case BS_CLEAN:
> @@ -244,6 +248,7 @@ static void __transition(struct dm_block *b, enum dm_block_state new_state)
> /* DOT: reading -> error */
> BUG_ON(!((b->state == BS_WRITING) ||
> (b->state == BS_READING)));
> + bm->error_count++;
> list_add_tail(&b->list, &bm->error_list);
> break;
> }
> @@ -450,6 +455,16 @@ static int recycle_block(struct dm_block_manager *bm, dm_block_t where,
> retry:
> while (1) {
> /*
> + * The calling thread may hold some locks on blocks, and
> + * the rest be errored. In which case we're never going to
> + * succeed here.
> + */
> + if (bm->error_count == bm->cache_size - bm->max_held_per_thread) {
> + spin_unlock_irqrestore(&bm->lock, flags);
> + return -ENOMEM;
> + }
> +
> + /*
> * Once we can lock and do io concurrently then we should
> * probably flush at bm->cache_size / 2 and write _all_
> * dirty blocks.
> @@ -599,7 +614,8 @@ static unsigned calc_hash_size(unsigned cache_size)
>
> struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
> unsigned block_size,
> - unsigned cache_size)
> + unsigned cache_size,
> + unsigned max_held_per_thread)
> {
> unsigned i;
> unsigned hash_size = calc_hash_size(cache_size);
> @@ -613,6 +629,7 @@ struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
>
> bm->bdev = bdev;
> bm->cache_size = max(MAX_CACHE_SIZE, cache_size);
> + bm->max_held_per_thread = max_held_per_thread;
> bm->block_size = block_size;
> bm->nr_blocks = i_size_read(bdev->bd_inode);
> do_div(bm->nr_blocks, block_size);
> @@ -623,6 +640,7 @@ struct dm_block_manager *dm_block_manager_create(struct block_device *bdev,
> INIT_LIST_HEAD(&bm->clean_list);
> INIT_LIST_HEAD(&bm->dirty_list);
> INIT_LIST_HEAD(&bm->error_list);
> + bm->error_count = 0;
> bm->available_count = 0;
> bm->reading_count = 0;
> bm->writing_count = 0;
> diff --git a/drivers/md/persistent-data/dm-block-manager.h b/drivers/md/persistent-data/dm-block-manager.h
> index ebea2d5..38c49c7 100644
> --- a/drivers/md/persistent-data/dm-block-manager.h
> +++ b/drivers/md/persistent-data/dm-block-manager.h
> @@ -37,7 +37,14 @@ static inline uint32_t dm_block_csum_data(const void *data_le, unsigned length)
> /*----------------------------------------------------------------*/
>
> struct dm_block_manager;
> -struct dm_block_manager *dm_block_manager_create(struct block_device *bdev, unsigned block_size, unsigned cache_size);
> +
> +/*
> + * @max_held_per_thread should be the maximum number of locks, read or
> + * write, that an individual thread holds at any one time.
> + */
> +struct dm_block_manager *dm_block_manager_create(
> + struct block_device *bdev, unsigned block_size,
> + unsigned cache_size, unsigned max_held_per_thread);
> void dm_block_manager_destroy(struct dm_block_manager *bm);
>
> unsigned dm_bm_block_size(struct dm_block_manager *bm);
> --
> 1.7.4.1
>

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