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path: root/drivers/md/dm-thin.c
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Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c147
1 files changed, 102 insertions, 45 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index a04eba905922..38a063f7afa4 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -130,10 +130,11 @@ static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
struct dm_thin_new_mapping;
/*
- * The pool runs in 3 modes. Ordered in degraded order for comparisons.
+ * The pool runs in 4 modes. Ordered in degraded order for comparisons.
*/
enum pool_mode {
PM_WRITE, /* metadata may be changed */
+ PM_OUT_OF_DATA_SPACE, /* metadata may be changed, though data may not be allocated */
PM_READ_ONLY, /* metadata may not be changed */
PM_FAIL, /* all I/O fails */
};
@@ -198,7 +199,6 @@ struct pool {
};
static enum pool_mode get_pool_mode(struct pool *pool);
-static void out_of_data_space(struct pool *pool);
static void metadata_operation_failed(struct pool *pool, const char *op, int r);
/*
@@ -399,6 +399,23 @@ static void requeue_io(struct thin_c *tc)
spin_unlock_irqrestore(&pool->lock, flags);
}
+static void error_retry_list(struct pool *pool)
+{
+ struct bio *bio;
+ unsigned long flags;
+ struct bio_list bios;
+
+ bio_list_init(&bios);
+
+ spin_lock_irqsave(&pool->lock, flags);
+ bio_list_merge(&bios, &pool->retry_on_resume_list);
+ bio_list_init(&pool->retry_on_resume_list);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ while ((bio = bio_list_pop(&bios)))
+ bio_io_error(bio);
+}
+
/*
* This section of code contains the logic for processing a thin device's IO.
* Much of the code depends on pool object resources (lists, workqueues, etc)
@@ -925,13 +942,15 @@ static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
}
}
+static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);
+
static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
{
int r;
dm_block_t free_blocks;
struct pool *pool = tc->pool;
- if (get_pool_mode(pool) != PM_WRITE)
+ if (WARN_ON(get_pool_mode(pool) != PM_WRITE))
return -EINVAL;
r = dm_pool_get_free_block_count(pool->pmd, &free_blocks);
@@ -958,7 +977,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
}
if (!free_blocks) {
- out_of_data_space(pool);
+ set_pool_mode(pool, PM_OUT_OF_DATA_SPACE);
return -ENOSPC;
}
}
@@ -988,15 +1007,32 @@ static void retry_on_resume(struct bio *bio)
spin_unlock_irqrestore(&pool->lock, flags);
}
-static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
+static bool should_error_unserviceable_bio(struct pool *pool)
{
- /*
- * When pool is read-only, no cell locking is needed because
- * nothing is changing.
- */
- WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY);
+ enum pool_mode m = get_pool_mode(pool);
+
+ switch (m) {
+ case PM_WRITE:
+ /* Shouldn't get here */
+ DMERR_LIMIT("bio unserviceable, yet pool is in PM_WRITE mode");
+ return true;
+
+ case PM_OUT_OF_DATA_SPACE:
+ return pool->pf.error_if_no_space;
+
+ case PM_READ_ONLY:
+ case PM_FAIL:
+ return true;
+ default:
+ /* Shouldn't get here */
+ DMERR_LIMIT("bio unserviceable, yet pool has an unknown mode");
+ return true;
+ }
+}
- if (pool->pf.error_if_no_space)
+static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
+{
+ if (should_error_unserviceable_bio(pool))
bio_io_error(bio);
else
retry_on_resume(bio);
@@ -1007,11 +1043,20 @@ static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *c
struct bio *bio;
struct bio_list bios;
+ if (should_error_unserviceable_bio(pool)) {
+ cell_error(pool, cell);
+ return;
+ }
+
bio_list_init(&bios);
cell_release(pool, cell, &bios);
- while ((bio = bio_list_pop(&bios)))
- handle_unserviceable_bio(pool, bio);
+ if (should_error_unserviceable_bio(pool))
+ while ((bio = bio_list_pop(&bios)))
+ bio_io_error(bio);
+ else
+ while ((bio = bio_list_pop(&bios)))
+ retry_on_resume(bio);
}
static void process_discard(struct thin_c *tc, struct bio *bio)
@@ -1296,6 +1341,11 @@ static void process_bio_read_only(struct thin_c *tc, struct bio *bio)
}
}
+static void process_bio_success(struct thin_c *tc, struct bio *bio)
+{
+ bio_endio(bio, 0);
+}
+
static void process_bio_fail(struct thin_c *tc, struct bio *bio)
{
bio_io_error(bio);
@@ -1399,9 +1449,15 @@ static enum pool_mode get_pool_mode(struct pool *pool)
return pool->pf.mode;
}
+static void notify_of_pool_mode_change(struct pool *pool, const char *new_mode)
+{
+ dm_table_event(pool->ti->table);
+ DMINFO("%s: switching pool to %s mode",
+ dm_device_name(pool->pool_md), new_mode);
+}
+
static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
{
- int r;
struct pool_c *pt = pool->ti->private;
bool needs_check = dm_pool_metadata_needs_check(pool->pmd);
enum pool_mode old_mode = get_pool_mode(pool);
@@ -1429,38 +1485,48 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
switch (new_mode) {
case PM_FAIL:
if (old_mode != new_mode)
- DMERR("%s: switching pool to failure mode",
- dm_device_name(pool->pool_md));
+ notify_of_pool_mode_change(pool, "failure");
dm_pool_metadata_read_only(pool->pmd);
pool->process_bio = process_bio_fail;
pool->process_discard = process_bio_fail;
pool->process_prepared_mapping = process_prepared_mapping_fail;
pool->process_prepared_discard = process_prepared_discard_fail;
+
+ error_retry_list(pool);
break;
case PM_READ_ONLY:
if (old_mode != new_mode)
- DMERR("%s: switching pool to read-only mode",
- dm_device_name(pool->pool_md));
- r = dm_pool_abort_metadata(pool->pmd);
- if (r) {
- DMERR("%s: aborting transaction failed",
- dm_device_name(pool->pool_md));
- new_mode = PM_FAIL;
- set_pool_mode(pool, new_mode);
- } else {
- dm_pool_metadata_read_only(pool->pmd);
- pool->process_bio = process_bio_read_only;
- pool->process_discard = process_discard;
- pool->process_prepared_mapping = process_prepared_mapping_fail;
- pool->process_prepared_discard = process_prepared_discard_passdown;
- }
+ notify_of_pool_mode_change(pool, "read-only");
+ dm_pool_metadata_read_only(pool->pmd);
+ pool->process_bio = process_bio_read_only;
+ pool->process_discard = process_bio_success;
+ pool->process_prepared_mapping = process_prepared_mapping_fail;
+ pool->process_prepared_discard = process_prepared_discard_passdown;
+
+ error_retry_list(pool);
+ break;
+
+ case PM_OUT_OF_DATA_SPACE:
+ /*
+ * Ideally we'd never hit this state; the low water mark
+ * would trigger userland to extend the pool before we
+ * completely run out of data space. However, many small
+ * IOs to unprovisioned space can consume data space at an
+ * alarming rate. Adjust your low water mark if you're
+ * frequently seeing this mode.
+ */
+ if (old_mode != new_mode)
+ notify_of_pool_mode_change(pool, "out-of-data-space");
+ pool->process_bio = process_bio_read_only;
+ pool->process_discard = process_discard;
+ pool->process_prepared_mapping = process_prepared_mapping;
+ pool->process_prepared_discard = process_prepared_discard_passdown;
break;
case PM_WRITE:
if (old_mode != new_mode)
- DMINFO("%s: switching pool to write mode",
- dm_device_name(pool->pool_md));
+ notify_of_pool_mode_change(pool, "write");
dm_pool_metadata_read_write(pool->pmd);
pool->process_bio = process_bio;
pool->process_discard = process_discard;
@@ -1477,17 +1543,6 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
pt->adjusted_pf.mode = new_mode;
}
-/*
- * Rather than calling set_pool_mode directly, use these which describe the
- * reason for mode degradation.
- */
-static void out_of_data_space(struct pool *pool)
-{
- DMERR_LIMIT("%s: no free data space available.",
- dm_device_name(pool->pool_md));
- set_pool_mode(pool, PM_READ_ONLY);
-}
-
static void abort_transaction(struct pool *pool)
{
const char *dev_name = dm_device_name(pool->pool_md);
@@ -2719,7 +2774,9 @@ static void pool_status(struct dm_target *ti, status_type_t type,
else
DMEMIT("- ");
- if (pool->pf.mode == PM_READ_ONLY)
+ if (pool->pf.mode == PM_OUT_OF_DATA_SPACE)
+ DMEMIT("out_of_data_space ");
+ else if (pool->pf.mode == PM_READ_ONLY)
DMEMIT("ro ");
else
DMEMIT("rw ");