diff options
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-thin.c | 147 |
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 "); |