Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.17 26/73] dm thin: fix missing out-of-data-space to write mode transition if blocks are released | Date | Tue, 6 Jan 2015 18:15:47 -0800 |
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3.17-stable review patch. If anyone has any objections, please let me know.
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From: Joe Thornber <ejt@redhat.com>
commit 2c43fd26e46734430122b8d2ad3024bb532df3ef upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/dm-thin.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -990,6 +990,24 @@ static void schedule_external_copy(struc 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. @@ -1004,6 +1022,8 @@ 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; } @@ -1022,8 +1042,6 @@ static void check_low_water_mark(struct } } -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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