Attachment 863191 Details for Bug 1065051 – Patch 1

Patch 1

for-3.14-18-20-dm-thin-fix-pool_preresume-resize-with-heavy-IO-races.patch (text/plain), 6.19 KB, created by Zdenek Kabelac on 2014-02-14 10:12:09 UTC

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Creator: Zdenek Kabelac

Created: 2014-02-14 10:12:09 UTC

Size: 6.19 KB

patch

obsolete

>diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
>index 7da3476..974e2cf 100644
>--- a/drivers/md/dm-thin-metadata.c
>+++ b/drivers/md/dm-thin-metadata.c
>@@ -1586,6 +1586,30 @@ int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
> 	return r;
> }
> 
>+int dm_pool_is_out_of_space(struct dm_pool_metadata *pmd, bool *result)
>+{
>+	int r;
>+	dm_block_t free_blocks;
>+
>+	*result = false;
>+
>+	r = dm_pool_get_free_block_count(pmd, &free_blocks);
>+	if (r)
>+		return r;
>+	if (!free_blocks) {
>+		*result = true;
>+		return 0;
>+	}
>+
>+	r = dm_pool_get_free_metadata_block_count(pmd, &free_blocks);
>+	if (r)
>+		return r;
>+	if (!free_blocks)
>+		*result = true;
>+
>+	return 0;
>+}
>+
> int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
> 				  dm_block_t *result)
> {
>@@ -1709,6 +1733,17 @@ int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_cou
> 	return r;
> }
> 
>+bool dm_pool_metadata_is_read_only(struct dm_pool_metadata *pmd)
>+{
>+	bool r;
>+
>+	down_read(&pmd->root_lock);
>+	r = pmd->read_only;
>+	up_read(&pmd->root_lock);
>+
>+	return r;
>+}
>+
> void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
> {
> 	down_write(&pmd->root_lock);
>diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h
>index 9a36856..dcbd08c 100644
>--- a/drivers/md/dm-thin-metadata.h
>+++ b/drivers/md/dm-thin-metadata.h
>@@ -177,6 +177,8 @@ int dm_pool_get_free_metadata_block_count(struct dm_pool_metadata *pmd,
> int dm_pool_get_metadata_dev_size(struct dm_pool_metadata *pmd,
> 				  dm_block_t *result);
> 
>+int dm_pool_is_out_of_space(struct dm_pool_metadata *pmd, bool *result);
>+
> int dm_pool_get_data_block_size(struct dm_pool_metadata *pmd, sector_t *result);
> 
> int dm_pool_get_data_dev_size(struct dm_pool_metadata *pmd, dm_block_t *result);
>@@ -194,6 +196,7 @@ int dm_pool_resize_metadata_dev(struct dm_pool_metadata *pmd, dm_block_t new_siz
>  * Flicks the underlying block manager into read only mode, so you know
>  * that nothing is changing.
>  */
>+bool dm_pool_metadata_is_read_only(struct dm_pool_metadata *pmd);
> void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd);
> void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd);
> 
>diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
>index 4a2432a..53dcdfb 100644
>--- a/drivers/md/dm-thin.c
>+++ b/drivers/md/dm-thin.c
>@@ -891,22 +891,43 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
> 	}
> }
> 
>+static int __commit(struct pool *pool)
>+{
>+	int r = dm_pool_commit_metadata(pool->pmd);
>+	if (r)
>+		metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
>+
>+	return r;
>+}
>+
>+/*
>+ * Commit that is confined to the metadata superblock due to pool
>+ * being in PM_READ_ONLY mode (read-only process_* functions).
>+ * A non-zero return indicates metadata is not writable.
>+ */
>+static int commit_metadata_superblock(struct pool *pool)
>+{
>+	WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY);
>+
>+	if (dm_pool_metadata_is_read_only(pool->pmd)) {
>+		DMERR_LIMIT("%s: commit failed: pool metadata is not writable",
>+			    dm_device_name(pool->pool_md));
>+		return -EINVAL;
>+	}
>+
>+	return __commit(pool);
>+}
>+
> /*
>  * A non-zero return indicates read_only or fail_io mode.
>  * Many callers don't care about the return value.
>  */
> static int commit(struct pool *pool)
> {
>-	int r;
>-
> 	if (get_pool_mode(pool) != PM_WRITE)
> 		return -EINVAL;
> 
>-	r = dm_pool_commit_metadata(pool->pmd);
>-	if (r)
>-		metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
>-
>-	return r;
>+	return __commit(pool);
> }
> 
> static void check_low_water_mark(struct pool *pool, dm_block_t free_blocks)
>@@ -1424,7 +1445,11 @@ static void set_pool_mode(struct pool *pool, enum pool_mode new_mode)
> 			new_mode = PM_FAIL;
> 			set_pool_mode(pool, new_mode);
> 		} else {
>-			dm_pool_metadata_read_only(pool->pmd);
>+			bool out_of_space;
>+			if (!dm_pool_is_out_of_space(pool->pmd, &out_of_space) && out_of_space)
>+				dm_pool_metadata_read_write(pool->pmd);
>+			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;
>@@ -1701,12 +1726,17 @@ static int bind_control_target(struct pool *pool, struct dm_target *ti)
> 	/*
> 	 * 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).
>+	 * pool move out of the old mode.  Similarly, if in PM_READ_ONLY mode
>+	 * and the pool doesn't have free space we must not switch modes here;
>+	 * pool_preresume() will transition to PM_WRITE mode if a resize succeeds.
> 	 */
> 	if (old_mode == PM_FAIL)
> 		new_mode = old_mode;
>+	else if (old_mode == PM_READ_ONLY) {
>+		bool out_of_space;
>+		if (!dm_pool_is_out_of_space(pool->pmd, &out_of_space) && out_of_space)
>+			new_mode = old_mode;
>+	}
> 
> 	set_pool_mode(pool, new_mode);
> 
>@@ -2317,6 +2347,7 @@ static int pool_preresume(struct dm_target *ti)
> 	bool need_commit1, need_commit2;
> 	struct pool_c *pt = ti->private;
> 	struct pool *pool = pt->pool;
>+	bool out_of_space = false;
> 
> 	/*
> 	 * Take control of the pool object.
>@@ -2325,6 +2356,12 @@ static int pool_preresume(struct dm_target *ti)
> 	if (r)
> 		return r;
> 
>+	if (get_pool_mode(pool) == PM_READ_ONLY) {
>+		r = dm_pool_is_out_of_space(pool->pmd, &out_of_space);
>+		if (r)
>+			metadata_operation_failed(pool, "dm_pool_is_out_of_space", r);
>+	}
>+
> 	r = maybe_resize_data_dev(ti, &need_commit1);
> 	if (r)
> 		return r;
>@@ -2333,8 +2370,23 @@ static int pool_preresume(struct dm_target *ti)
> 	if (r)
> 		return r;
> 
>-	if (need_commit1 || need_commit2)
>-		(void) commit(pool);
>+	if (need_commit1 || need_commit2) {
>+		if (out_of_space) {
>+			/*
>+			 * Must update metadata's superblock despite read-only mode.
>+			 */
>+			r = commit_metadata_superblock(pool);
>+			if (r || pt->requested_pf.mode == PM_READ_ONLY)
>+				dm_pool_metadata_read_only(pool->pmd);
>+			else {
>+				/*
>+				 * If resize succeeded transition the pool to write mode.
>+				 */
>+				set_pool_mode(pool, PM_WRITE);
>+			}
>+		} else
>+			(void) commit(pool);
>+	}
> 
> 	return 0;
> }

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Attachments on bug 1065051: 863191 | 863192 | 863524