dm thin: fix missing out-of-data-space to write mode transition if blocks are released (2c43fd26) · Commits · 戴 / test

Discard bios and thin device deletion have the potential to release data blocks. If the thin-pool is in out-of-data-space mode, and blocks were released, transition the thin-pool back to full write mode. The correct time to do this is just after the thin-pool metadata commit. It cannot be done before the commit because the space maps will not allow immediate reuse of the data blocks in case there's a rollback following power failure. Signed-off-by:

Joe Thornber <ejt@redhat.com> Signed-off-by:

Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org

drivers/md/dm-thin.c

+20 −2

Original line number	Diff line number	Diff line
		@@ -1127,6 +1127,24 @@ static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
		schedule_zero(tc, virt_block, data_dest, cell, bio);
		}

		static void set_pool_mode(struct pool *pool, enum pool_mode new_mode);

		static void check_for_space(struct pool *pool)
		{
		int r;
		dm_block_t nr_free;

		if (get_pool_mode(pool) != PM_OUT_OF_DATA_SPACE)
		return;

		r = dm_pool_get_free_block_count(pool->pmd, &nr_free);
		if (r)
		return;

		if (nr_free)
		set_pool_mode(pool, PM_WRITE);
		}

		/*
		* A non-zero return indicates read_only or fail_io mode.
		* Many callers don't care about the return value.
		@@ -1141,6 +1159,8 @@ static int commit(struct pool *pool)
		r = dm_pool_commit_metadata(pool->pmd);
		if (r)
		metadata_operation_failed(pool, "dm_pool_commit_metadata", r);
		else
		check_for_space(pool);

		return r;
		}
		@@ -1159,8 +1179,6 @@ 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;

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