1 files changed, 235 insertions, 69 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 7e84baccf0ad..be70d38745f7 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);
 
 /*
@@ -226,6 +226,7 @@ struct thin_c {
 
         struct pool *pool;
         struct dm_thin_device *td;
+        bool requeue_mode:1;
 };
 
 /*----------------------------------------------------------------*/
@@ -369,14 +370,18 @@ struct dm_thin_endio_hook {
         struct dm_thin_new_mapping *overwrite_mapping;
 };
 
-static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
+static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
 {
         struct bio *bio;
         struct bio_list bios;
+        unsigned long flags;
 
         bio_list_init(&bios);
+
+        spin_lock_irqsave(&tc->pool->lock, flags);
         bio_list_merge(&bios, master);
         bio_list_init(master);
+        spin_unlock_irqrestore(&tc->pool->lock, flags);
 
         while ((bio = bio_list_pop(&bios))) {
                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
@@ -391,12 +396,26 @@ static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
 static void requeue_io(struct thin_c *tc)
 {
         struct pool *pool = tc->pool;
+
+        requeue_bio_list(tc, &pool->deferred_bios);
+        requeue_bio_list(tc, &pool->retry_on_resume_list);
+}
+
+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);
-        __requeue_bio_list(tc, &pool->deferred_bios);
-        __requeue_bio_list(tc, &pool->retry_on_resume_list);
+        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);
 }
 
 /*
@@ -925,13 +944,15 @@ 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 +979,7 @@ 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 +1009,32 @@ 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;
 
-        if (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;
+        }
+}
+
+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 +1045,20 @@ 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 +1343,11 @@ 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);
@@ -1328,6 +1380,11 @@ static void process_deferred_bios(struct pool *pool)
                 struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
                 struct thin_c *tc = h->tc;
 
+                if (tc->requeue_mode) {
+                        bio_endio(bio, DM_ENDIO_REQUEUE);
+                        continue;
+                }
+
                 /*
                  * If we've got no free new_mapping structs, and processing
                  * this bio might require one, we pause until there are some
@@ -1394,51 +1451,134 @@ static void do_waker(struct work_struct *ws)
 
 /*----------------------------------------------------------------*/
 
+struct noflush_work {
+        struct work_struct worker;
+        struct thin_c *tc;
+
+        atomic_t complete;
+        wait_queue_head_t wait;
+};
+
+static void complete_noflush_work(struct noflush_work *w)
+{
+        atomic_set(&w->complete, 1);
+        wake_up(&w->wait);
+}
+
+static void do_noflush_start(struct work_struct *ws)
+{
+        struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+        w->tc->requeue_mode = true;
+        requeue_io(w->tc);
+        complete_noflush_work(w);
+}
+
+static void do_noflush_stop(struct work_struct *ws)
+{
+        struct noflush_work *w = container_of(ws, struct noflush_work, worker);
+        w->tc->requeue_mode = false;
+        complete_noflush_work(w);
+}
+
+static void noflush_work(struct thin_c *tc, void (*fn)(struct work_struct *))
+{
+        struct noflush_work w;
+
+        INIT_WORK(&w.worker, fn);
+        w.tc = tc;
+        atomic_set(&w.complete, 0);
+        init_waitqueue_head(&w.wait);
+
+        queue_work(tc->pool->wq, &w.worker);
+
+        wait_event(w.wait, atomic_read(&w.complete));
+}
+
+/*----------------------------------------------------------------*/
+
 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;
-        enum pool_mode old_mode = pool->pf.mode;
+        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);
+
+        /*
+         * Never allow the pool to transition to PM_WRITE mode if user
+         * intervention is required to verify metadata and data consistency.
+         */
+        if (new_mode == PM_WRITE && needs_check) {
+                DMERR("%s: unable to switch pool to write mode until repaired.",
+                      dm_device_name(pool->pool_md));
+                if (old_mode != new_mode)
+                        new_mode = old_mode;
+                else
+                        new_mode = PM_READ_ONLY;
+        }
+        /*
+         * If we were in PM_FAIL mode, rollback of metadata failed.  We're
+         * not going to recover without a thin_repair.  So we never let the
+         * pool move out of the old mode.
+         */
+        if (old_mode == PM_FAIL)
+                new_mode = old_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;
@@ -1448,32 +1588,35 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
         }
 
         pool->pf.mode = new_mode;
+        /*
+         * The pool mode may have changed, sync it so bind_control_target()
+         * doesn't cause an unexpected mode transition on resume.
+         */
+        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)
+static void abort_transaction(struct pool *pool)
 {
-        DMERR_LIMIT("%s: no free data space available.",
-                    dm_device_name(pool->pool_md));
-        set_pool_mode(pool, PM_READ_ONLY);
+        const char *dev_name = dm_device_name(pool->pool_md);
+
+        DMERR_LIMIT("%s: aborting current metadata transaction", dev_name);
+        if (dm_pool_abort_metadata(pool->pmd)) {
+                DMERR("%s: failed to abort metadata transaction", dev_name);
+                set_pool_mode(pool, PM_FAIL);
+        }
+
+        if (dm_pool_metadata_set_needs_check(pool->pmd)) {
+                DMERR("%s: failed to set 'needs_check' flag in metadata", dev_name);
+                set_pool_mode(pool, PM_FAIL);
+        }
 }
 
 static void metadata_operation_failed(struct pool *pool, const char *op, int r)
 {
-        dm_block_t free_blocks;
-
         DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
                     dm_device_name(pool->pool_md), op, r);
 
-        if (r == -ENOSPC &&
-            !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
-            !free_blocks)
-                DMERR_LIMIT("%s: no free metadata space available.",
-                            dm_device_name(pool->pool_md));
-
+        abort_transaction(pool);
         set_pool_mode(pool, PM_READ_ONLY);
 }
 
@@ -1524,6 +1667,11 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
 
         thin_hook_bio(tc, bio);
 
+        if (tc->requeue_mode) {
+                bio_endio(bio, DM_ENDIO_REQUEUE);
+                return DM_MAPIO_SUBMITTED;
+        }
+
         if (get_pool_mode(tc->pool) == PM_FAIL) {
                 bio_io_error(bio);
                 return DM_MAPIO_SUBMITTED;
@@ -1687,7 +1835,7 @@ static int bind_control_target(struct pool *pool, struct dm_target *ti)
         /*
          * We want to make sure that a pool in PM_FAIL mode is never upgraded.
          */
-        enum pool_mode old_mode = pool->pf.mode;
+        enum pool_mode old_mode = get_pool_mode(pool);
         enum pool_mode new_mode = pt->adjusted_pf.mode;
 
         /*
@@ -1701,16 +1849,6 @@ static int bind_control_target(struct pool *pool, struct dm_target *ti)
         pool->pf = pt->adjusted_pf;
         pool->low_water_blocks = pt->low_water_blocks;
 
-        /*
-         * If we were in PM_FAIL mode, rollback of metadata failed.  We're
-         * not going to recover without a thin_repair.  So we never let the
-         * pool move out of the old mode.  On the other hand a PM_READ_ONLY
-         * may have been due to a lack of metadata or data space, and may
-         * now work (ie. if the underlying devices have been resized).
-         */
-        if (old_mode == PM_FAIL)
-                new_mode = old_mode;
-
         set_pool_mode(pool, new_mode);
 
         return 0;
@@ -2253,6 +2391,12 @@ static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
                 return -EINVAL;
 
         } else if (data_size > sb_data_size) {
+                if (dm_pool_metadata_needs_check(pool->pmd)) {
+                        DMERR("%s: unable to grow the data device until repaired.",
+                              dm_device_name(pool->pool_md));
+                        return 0;
+                }
+
                 if (sb_data_size)
                         DMINFO("%s: growing the data device from %llu to %llu blocks",
                                dm_device_name(pool->pool_md),
@@ -2294,6 +2438,12 @@ static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
                 return -EINVAL;
 
         } else if (metadata_dev_size > sb_metadata_dev_size) {
+                if (dm_pool_metadata_needs_check(pool->pmd)) {
+                        DMERR("%s: unable to grow the metadata device until repaired.",
+                              dm_device_name(pool->pool_md));
+                        return 0;
+                }
+
                 warn_if_metadata_device_too_big(pool->md_dev);
                 DMINFO("%s: growing the metadata device from %llu to %llu blocks",
                        dm_device_name(pool->pool_md),
@@ -2681,7 +2831,9 @@ 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 ");
@@ -2795,7 +2947,7 @@ static struct target_type pool_target = {
         .name = "thin-pool",
         .features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
                     DM_TARGET_IMMUTABLE,
-        .version = {1, 10, 0},
+        .version = {1, 11, 0},
         .module = THIS_MODULE,
         .ctr = pool_ctr,
         .dtr = pool_dtr,
@@ -2997,10 +3149,23 @@ static int thin_endio(struct dm_target *ti, struct bio *bio, int err)
         return 0;
 }
 
-static void thin_postsuspend(struct dm_target *ti)
+static void thin_presuspend(struct dm_target *ti)
 {
+        struct thin_c *tc = ti->private;
+
         if (dm_noflush_suspending(ti))
-                requeue_io((struct thin_c *)ti->private);
+                noflush_work(tc, do_noflush_start);
+}
+
+static void thin_postsuspend(struct dm_target *ti)
+{
+        struct thin_c *tc = ti->private;
+
+        /*
+         * The dm_noflush_suspending flag has been cleared by now, so
+         * unfortunately we must always run this.
+         */
+        noflush_work(tc, do_noflush_stop);
 }
 
 /*
@@ -3085,12 +3250,13 @@ static int thin_iterate_devices(struct dm_target *ti,
 
 static struct target_type thin_target = {
         .name = "thin",
-        .version = {1, 10, 0},
+        .version = {1, 11, 0},
         .module = THIS_MODULE,
         .ctr = thin_ctr,
         .dtr = thin_dtr,
         .map = thin_map,
         .end_io = thin_endio,
+        .presuspend = thin_presuspend,
         .postsuspend = thin_postsuspend,
         .status = thin_status,
         .iterate_devices = thin_iterate_devices,