Re: [PATCH 1/2] dm: update table type check for dax
From: Mike Snitzer <hidden>
Date: 2016-06-28 20:07:19
Also in:
dm-devel, lkml, nvdimm
On Tue, Jun 28 2016 at 3:37pm -0400, Toshi Kani [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Allow table type DM_TYPE_BIO_BASED to extend with DM_TYPE_DAX_BIO_BASED since DM_TYPE_DAX_BIO_BASED supports bio-based requests. Signed-off-by: Toshi Kani <redacted> Cc: Mike Snitzer <redacted> Cc: Alasdair Kergon <redacted> Cc: Dan Williams <redacted> --- drivers/md/dm-ioctl.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index b59e3459..0f32791 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c@@ -1267,6 +1267,15 @@ static int populate_table(struct dm_table *table, return dm_table_complete(table); } +static bool is_valid_type(unsigned cur, unsigned new) +{ + if (cur == new || + (cur == DM_TYPE_BIO_BASED && new == DM_TYPE_DAX_BIO_BASED)) + return true; + + return false; +} + static int table_load(struct dm_ioctl *param, size_t param_size) { int r;@@ -1309,7 +1318,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size) DMWARN("unable to set up device queue for new table."); goto err_unlock_md_type; } - } else if (dm_get_md_type(md) != dm_table_get_type(t)) { + } else if (!is_valid_type(dm_get_md_type(md), dm_table_get_type(t))) { DMWARN("can't change device type after initial table load."); r = -EINVAL; goto err_unlock_md_type;
You said in the 0th header: "Patch 1 solves an error when lvremove is made to a snapshot device." I'm not seeing why this patch 1 fixes anything specific to snapshot device removal (but I can see why patch 2 makes snapshot creation "work"). I'll apply your 2nd patch and see if I can see what you mean. I actually see this error, without either of your 2 proposed patches applied, when I try to create a snapshot of a DAX capable LV: # lvcreate -s -n snap -L 100M pmem/lv device-mapper: reload ioctl on (253:7) failed: Invalid argument Failed to lock logical volume pmem/lv. Aborting. Manual intervention required. Jun 28 15:57:28 rhel-storage-02 kernel: device-mapper: ioctl: can't change device type after initial table load.