From: Mikulas Patocka <mpatocka@redhat.com> To: Jens Axboe <axboe@kernel.dk>, Zdenek Kabelac <zkabelac@redhat.com> Cc: linux-block@vger.kernel.org, dm-devel@redhat.com Subject: [dm-devel] [PATCH 4/4] brd: implement secure erase and write zeroes Date: Fri, 16 Sep 2022 05:00:46 -0400 (EDT) [thread overview] Message-ID: <alpine.LRH.2.02.2209160500190.543@file01.intranet.prod.int.rdu2.redhat.com> (raw) In-Reply-To: <alpine.LRH.2.02.2209151604410.13231@file01.intranet.prod.int.rdu2.redhat.com> This patch implements REQ_OP_SECURE_ERASE and REQ_OP_WRITE_ZEROES on brd. Write zeroes will free the pages just like discard, but the difference is that it writes zeroes to the preceding and following page if the range is not aligned on page boundary. Secure erase is just like write zeroes, except that it clears the page content before freeing the page. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- drivers/block/brd.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) Index: linux-2.6/drivers/block/brd.c =================================================================== --- linux-2.6.orig/drivers/block/brd.c +++ linux-2.6/drivers/block/brd.c @@ -118,7 +118,7 @@ static void brd_free_page_rcu(struct rcu __free_page(page); } -static void brd_free_page(struct brd_device *brd, sector_t sector) +static void brd_free_page(struct brd_device *brd, sector_t sector, bool secure) { struct page *page; pgoff_t idx; @@ -127,8 +127,11 @@ static void brd_free_page(struct brd_dev idx = sector >> PAGE_SECTORS_SHIFT; page = radix_tree_delete(&brd->brd_pages, idx); spin_unlock(&brd->brd_lock); - if (page) + if (page) { + if (secure) + clear_highpage(page); call_rcu(&page->rcu_head, brd_free_page_rcu); + } } /* @@ -308,16 +311,29 @@ static void brd_submit_bio(struct bio *b struct bio_vec bvec; struct bvec_iter iter; - if (bio_op(bio) == REQ_OP_DISCARD) { + if (bio_op(bio) == REQ_OP_DISCARD || + bio_op(bio) == REQ_OP_SECURE_ERASE || + bio_op(bio) == REQ_OP_WRITE_ZEROES) { + bool zero_padding = bio_op(bio) == REQ_OP_SECURE_ERASE || bio_op(bio) == REQ_OP_WRITE_ZEROES; sector_t len = bio_sectors(bio); sector_t front_pad = -sector & (PAGE_SECTORS - 1); + sector_t end_pad; + + if (zero_padding && unlikely(front_pad != 0)) + copy_to_brd(brd, page_address(ZERO_PAGE(0)), sector, min(len, front_pad) << SECTOR_SHIFT); + sector += front_pad; if (unlikely(len <= front_pad)) goto endio; len -= front_pad; - len = round_down(len, PAGE_SECTORS); + + end_pad = len & (PAGE_SECTORS - 1); + if (zero_padding && unlikely(end_pad != 0)) + copy_to_brd(brd, page_address(ZERO_PAGE(0)), sector + len - end_pad, end_pad << SECTOR_SHIFT); + len -= end_pad; + while (len) { - brd_free_page(brd, sector); + brd_free_page(brd, sector, bio_op(bio) == REQ_OP_SECURE_ERASE); sector += PAGE_SECTORS; len -= PAGE_SECTORS; cond_resched(); @@ -448,6 +464,8 @@ static int brd_alloc(int i) disk->queue->limits.discard_granularity = PAGE_SIZE; blk_queue_max_discard_sectors(disk->queue, UINT_MAX); + blk_queue_max_write_zeroes_sectors(disk->queue, UINT_MAX); + blk_queue_max_secure_erase_sectors(disk->queue, UINT_MAX); /* Tell the block layer that this is not a rotational device */ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue); -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com> To: Jens Axboe <axboe@kernel.dk>, Zdenek Kabelac <zkabelac@redhat.com> Cc: linux-block@vger.kernel.org, dm-devel@redhat.com Subject: [PATCH 4/4] brd: implement secure erase and write zeroes Date: Fri, 16 Sep 2022 05:00:46 -0400 (EDT) [thread overview] Message-ID: <alpine.LRH.2.02.2209160500190.543@file01.intranet.prod.int.rdu2.redhat.com> (raw) In-Reply-To: <alpine.LRH.2.02.2209151604410.13231@file01.intranet.prod.int.rdu2.redhat.com> This patch implements REQ_OP_SECURE_ERASE and REQ_OP_WRITE_ZEROES on brd. Write zeroes will free the pages just like discard, but the difference is that it writes zeroes to the preceding and following page if the range is not aligned on page boundary. Secure erase is just like write zeroes, except that it clears the page content before freeing the page. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- drivers/block/brd.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) Index: linux-2.6/drivers/block/brd.c =================================================================== --- linux-2.6.orig/drivers/block/brd.c +++ linux-2.6/drivers/block/brd.c @@ -118,7 +118,7 @@ static void brd_free_page_rcu(struct rcu __free_page(page); } -static void brd_free_page(struct brd_device *brd, sector_t sector) +static void brd_free_page(struct brd_device *brd, sector_t sector, bool secure) { struct page *page; pgoff_t idx; @@ -127,8 +127,11 @@ static void brd_free_page(struct brd_dev idx = sector >> PAGE_SECTORS_SHIFT; page = radix_tree_delete(&brd->brd_pages, idx); spin_unlock(&brd->brd_lock); - if (page) + if (page) { + if (secure) + clear_highpage(page); call_rcu(&page->rcu_head, brd_free_page_rcu); + } } /* @@ -308,16 +311,29 @@ static void brd_submit_bio(struct bio *b struct bio_vec bvec; struct bvec_iter iter; - if (bio_op(bio) == REQ_OP_DISCARD) { + if (bio_op(bio) == REQ_OP_DISCARD || + bio_op(bio) == REQ_OP_SECURE_ERASE || + bio_op(bio) == REQ_OP_WRITE_ZEROES) { + bool zero_padding = bio_op(bio) == REQ_OP_SECURE_ERASE || bio_op(bio) == REQ_OP_WRITE_ZEROES; sector_t len = bio_sectors(bio); sector_t front_pad = -sector & (PAGE_SECTORS - 1); + sector_t end_pad; + + if (zero_padding && unlikely(front_pad != 0)) + copy_to_brd(brd, page_address(ZERO_PAGE(0)), sector, min(len, front_pad) << SECTOR_SHIFT); + sector += front_pad; if (unlikely(len <= front_pad)) goto endio; len -= front_pad; - len = round_down(len, PAGE_SECTORS); + + end_pad = len & (PAGE_SECTORS - 1); + if (zero_padding && unlikely(end_pad != 0)) + copy_to_brd(brd, page_address(ZERO_PAGE(0)), sector + len - end_pad, end_pad << SECTOR_SHIFT); + len -= end_pad; + while (len) { - brd_free_page(brd, sector); + brd_free_page(brd, sector, bio_op(bio) == REQ_OP_SECURE_ERASE); sector += PAGE_SECTORS; len -= PAGE_SECTORS; cond_resched(); @@ -448,6 +464,8 @@ static int brd_alloc(int i) disk->queue->limits.discard_granularity = PAGE_SIZE; blk_queue_max_discard_sectors(disk->queue, UINT_MAX); + blk_queue_max_write_zeroes_sectors(disk->queue, UINT_MAX); + blk_queue_max_secure_erase_sectors(disk->queue, UINT_MAX); /* Tell the block layer that this is not a rotational device */ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
next prev parent reply other threads:[~2022-09-16 9:00 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-16 8:58 [PATCH 0/4] brd: implement discard Mikulas Patocka 2022-09-16 8:58 ` [dm-devel] " Mikulas Patocka 2022-09-16 8:59 ` [PATCH 1/4] brd: make brd_insert_page return bool Mikulas Patocka 2022-09-16 8:59 ` [dm-devel] " Mikulas Patocka 2022-09-20 7:28 ` Christoph Hellwig 2022-09-20 7:28 ` [dm-devel] " Christoph Hellwig 2022-09-16 8:59 ` [PATCH 2/4] brd: extend the rcu regions to cover read and write Mikulas Patocka 2022-09-16 8:59 ` [dm-devel] " Mikulas Patocka 2022-09-20 7:38 ` Christoph Hellwig 2022-09-20 7:38 ` [dm-devel] " Christoph Hellwig 2022-09-16 9:00 ` [dm-devel] [PATCH 3/4] brd: enable discard Mikulas Patocka 2022-09-16 9:00 ` Mikulas Patocka 2022-09-20 7:39 ` [dm-devel] " Christoph Hellwig 2022-09-20 7:39 ` Christoph Hellwig 2022-09-20 17:47 ` [dm-devel] " Mikulas Patocka 2022-09-20 17:47 ` Mikulas Patocka 2022-09-16 9:00 ` Mikulas Patocka [this message] 2022-09-16 9:00 ` [PATCH 4/4] brd: implement secure erase and write zeroes Mikulas Patocka 2022-09-20 7:29 ` Christoph Hellwig 2022-09-20 7:29 ` [dm-devel] " Christoph Hellwig 2022-09-20 17:46 ` Mikulas Patocka 2022-09-20 17:46 ` Mikulas Patocka
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