Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753017Ab3HVCu3 (ORCPT ); Wed, 21 Aug 2013 22:50:29 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:50693 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752171Ab3HVCu2 (ORCPT ); Wed, 21 Aug 2013 22:50:28 -0400 Message-ID: <52157C6E.6080406@oracle.com> Date: Thu, 22 Aug 2013 10:50:22 +0800 From: Joe Jin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 MIME-Version: 1.0 To: Mikulas Patocka CC: device-mapper development , Mike Snitzer , Alasdair Kergon , "linux-kernel@vger.kernel.org" Subject: Re: [dm-devel] [PATCH v2] dm ioctl: allow change device target type to error References: <5214CC25.1070307@oracle.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4604 Lines: 143 Mikulas, thanks for you suggestions, I create new patch, can you please help review? Subject: dm: add map_rq define for error commit a5664da "dm ioctl: make bio or request based device type immutable" prevented "dmsetup wape_table" change the target type to "error" for there is not map_rq for error target type. Signed-off-by: Joe Jin --- drivers/md/dm-target.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c index 37ba5db..b690910 100644 --- a/drivers/md/dm-target.c +++ b/drivers/md/dm-target.c @@ -131,12 +131,19 @@ static int io_err_map(struct dm_target *tt, struct bio *bio) return -EIO; } +static int io_err_map_rq(struct dm_target *ti, struct request *clone, + union map_info *map_context) +{ + return -EIO; +} + static struct target_type error_target = { .name = "error", .version = {1, 1, 0}, .ctr = io_err_ctr, .dtr = io_err_dtr, .map = io_err_map, + .map_rq = io_err_map_rq, }; int __init dm_target_init(void) -- 1.8.3.1 On 08/21/13 22:48, Mikulas Patocka wrote: > > > On Wed, 21 Aug 2013, Joe Jin wrote: > >> commit a5664da "dm ioctl: make bio or request based device type immutable" >> prevented "dmsetup wape_table" change the target type to "error". > > That commit a5664da is there for a reason (it is not possible to change > bio-based device to request-based and vice versa) and I don't really see > how this patch is supposed to work. > > If there are bios that are in flight and that already passed through > blk_queue_bio, and you change the device from request-based to bio-based, > what are you going to do with them? - The patch doesn't do anything about > it. > > A better approach would be to create a new request-based target "error-rq" > and change the multipath target to "error-rq" target. That way, you don't > have to change device type from request based to bio based. > > Mikulas > >> -v2: setup md->queue even target type is "error". >> >> Signed-off-by: Joe Jin >> --- >> drivers/md/dm-ioctl.c | 4 ++++ >> drivers/md/dm-table.c | 12 ++++++++++++ >> drivers/md/dm.h | 1 + >> 3 files changed, 17 insertions(+) >> >> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c >> index f1b7586..2a9b63d 100644 >> --- a/drivers/md/dm-ioctl.c >> +++ b/drivers/md/dm-ioctl.c >> @@ -1280,6 +1280,9 @@ static int table_load(struct dm_ioctl *param, size_t param_size) >> goto out; >> } >> >> + if (dm_is_error_target(t)) >> + goto error_target; >> + >> /* Protect md->type and md->queue against concurrent table loads. */ >> dm_lock_md_type(md); >> if (dm_get_md_type(md) == DM_TYPE_NONE) >> @@ -1293,6 +1296,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size) >> goto out; >> } >> >> +error_target: >> /* setup md->queue to reflect md's type (may block) */ >> r = dm_setup_md_queue(md); >> if (r) { >> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c >> index f221812..27be46a 100644 >> --- a/drivers/md/dm-table.c >> +++ b/drivers/md/dm-table.c >> @@ -184,6 +184,18 @@ static int alloc_targets(struct dm_table *t, unsigned int num) >> return 0; >> } >> >> +bool dm_is_error_target(struct dm_table *t) >> +{ >> + unsigned i; >> + >> + for (i = 0; i < t->num_targets; i++) { >> + struct dm_target *tgt = t->targets + i; >> + if (strcmp(tgt->type->name, "error") == 0) >> + return true; >> + } >> + return false; >> +} >> + >> int dm_table_create(struct dm_table **result, fmode_t mode, >> unsigned num_targets, struct mapped_device *md) >> { >> diff --git a/drivers/md/dm.h b/drivers/md/dm.h >> index 45b97da..c7bceeb 100644 >> --- a/drivers/md/dm.h >> +++ b/drivers/md/dm.h >> @@ -69,6 +69,7 @@ unsigned dm_table_get_type(struct dm_table *t); >> struct target_type *dm_table_get_immutable_target_type(struct dm_table *t); >> bool dm_table_request_based(struct dm_table *t); >> bool dm_table_supports_discards(struct dm_table *t); >> +bool dm_is_error_target(struct dm_table *t); >> int dm_table_alloc_md_mempools(struct dm_table *t); >> void dm_table_free_md_mempools(struct dm_table *t); >> struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t); >> -- >> 1.8.3.1 >> >> -- >> dm-devel mailing list >> dm-devel@redhat.com >> https://www.redhat.com/mailman/listinfo/dm-devel >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/