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[68.160.166.30]) by smtp.gmail.com with ESMTPSA id b126-20020ae9eb84000000b007468b183a65sm11345416qkg.30.2023.03.27.13.13.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Mar 2023 13:13:31 -0700 (PDT) From: Mike Snitzer To: dm-devel@redhat.com Cc: linux-block@vger.kernel.org, axboe@kernel.dk, ejt@redhat.com, mpatocka@redhat.com, heinzm@redhat.com, nhuck@google.com, ebiggers@kernel.org, keescook@chromium.org, luomeng12@huawei.com, Mike Snitzer Subject: [dm-6.4 PATCH v3 15/20] dm bio prison v1: add dm_cell_key_has_valid_range Date: Mon, 27 Mar 2023 16:11:38 -0400 Message-Id: <20230327201143.51026-16-snitzer@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230327201143.51026-1-snitzer@kernel.org> References: <20230327201143.51026-1-snitzer@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Don't have bio_detain() BUG_ON if a dm_cell_key is beyond BIO_PRISON_MAX_RANGE or spans a boundary. Update dm-thin.c:build_key() to use dm_cell_key_has_valid_range() which will do this checking without using BUG_ON. Also update process_discard_bio() to check the discard bio that DM core passes in (having first imposed max_discard_granularity based splitting). dm_cell_key_has_valid_range() will merely WARN_ON_ONCE if it returns false because if it does: it is programmer error that should be caught with proper testing. So relax the BUG_ONs to be WARN_ON_ONCE. Signed-off-by: Mike Snitzer --- drivers/md/dm-bio-prison-v1.c | 14 +++++++++----- drivers/md/dm-bio-prison-v1.h | 5 +++++ drivers/md/dm-thin.c | 21 +++++++++++++++------ 3 files changed, 29 insertions(+), 11 deletions(-) diff --git a/drivers/md/dm-bio-prison-v1.c b/drivers/md/dm-bio-prison-v1.c index 2b8af861e5f6..78bb559b521c 100644 --- a/drivers/md/dm-bio-prison-v1.c +++ b/drivers/md/dm-bio-prison-v1.c @@ -120,12 +120,17 @@ static unsigned lock_nr(struct dm_cell_key *key) return (key->block_begin >> BIO_PRISON_MAX_RANGE_SHIFT) & LOCK_MASK; } -static void check_range(struct dm_cell_key *key) +bool dm_cell_key_has_valid_range(struct dm_cell_key *key) { - BUG_ON(key->block_end - key->block_begin > BIO_PRISON_MAX_RANGE); - BUG_ON((key->block_begin >> BIO_PRISON_MAX_RANGE_SHIFT) != - ((key->block_end - 1) >> BIO_PRISON_MAX_RANGE_SHIFT)); + if (WARN_ON_ONCE(key->block_end - key->block_begin > BIO_PRISON_MAX_RANGE)) + return false; + if (WARN_ON_ONCE((key->block_begin >> BIO_PRISON_MAX_RANGE_SHIFT) != + (key->block_end - 1) >> BIO_PRISON_MAX_RANGE_SHIFT)) + return false; + + return true; } +EXPORT_SYMBOL(dm_cell_key_has_valid_range); static int __bio_detain(struct rb_root *root, struct dm_cell_key *key, @@ -172,7 +177,6 @@ static int bio_detain(struct dm_bio_prison *prison, { int r; unsigned l = lock_nr(key); - check_range(key); spin_lock_irq(&prison->regions[l].lock); r = __bio_detain(&prison->regions[l].cell, key, inmate, cell_prealloc, cell_result); diff --git a/drivers/md/dm-bio-prison-v1.h b/drivers/md/dm-bio-prison-v1.h index 0b8acd6708fb..2a097ed0d85e 100644 --- a/drivers/md/dm-bio-prison-v1.h +++ b/drivers/md/dm-bio-prison-v1.h @@ -83,6 +83,11 @@ int dm_get_cell(struct dm_bio_prison *prison, struct dm_bio_prison_cell *cell_prealloc, struct dm_bio_prison_cell **cell_result); +/* + * Returns false if key is beyond BIO_PRISON_MAX_RANGE or spans a boundary. + */ +bool dm_cell_key_has_valid_range(struct dm_cell_key *key); + /* * An atomic op that combines retrieving or creating a cell, and adding a * bio to it. diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 33ad5695f959..2b13c949bd72 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -118,25 +118,27 @@ enum lock_space { PHYSICAL }; -static void build_key(struct dm_thin_device *td, enum lock_space ls, +static bool build_key(struct dm_thin_device *td, enum lock_space ls, dm_block_t b, dm_block_t e, struct dm_cell_key *key) { key->virtual = (ls == VIRTUAL); key->dev = dm_thin_dev_id(td); key->block_begin = b; key->block_end = e; + + return dm_cell_key_has_valid_range(key); } static void build_data_key(struct dm_thin_device *td, dm_block_t b, struct dm_cell_key *key) { - build_key(td, PHYSICAL, b, b + 1llu, key); + (void) build_key(td, PHYSICAL, b, b + 1llu, key); } static void build_virtual_key(struct dm_thin_device *td, dm_block_t b, struct dm_cell_key *key) { - build_key(td, VIRTUAL, b, b + 1llu, key); + (void) build_key(td, VIRTUAL, b, b + 1llu, key); } /*----------------------------------------------------------------*/ @@ -1702,7 +1704,8 @@ static void break_up_discard_bio(struct thin_c *tc, dm_block_t begin, dm_block_t << BIO_PRISON_MAX_RANGE_SHIFT; len = min_t(sector_t, data_end - data_begin, next_boundary - data_begin); - build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key); + /* This key is certainly within range given the above splitting */ + (void) build_key(tc->td, PHYSICAL, data_begin, data_begin + len, &data_key); if (bio_detain(tc->pool, &data_key, NULL, &data_cell)) { /* contention, we'll give up with this range */ data_begin += len; @@ -1778,8 +1781,13 @@ static void process_discard_bio(struct thin_c *tc, struct bio *bio) return; } - build_key(tc->td, VIRTUAL, begin, end, &virt_key); - if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) + if (unlikely(!build_key(tc->td, VIRTUAL, begin, end, &virt_key))) { + DMERR_LIMIT("Discard doesn't respect bio prison limits"); + bio_endio(bio); + return; + } + + if (bio_detain(tc->pool, &virt_key, bio, &virt_cell)) { /* * Potential starvation issue: We're relying on the * fs/application being well behaved, and not trying to @@ -1788,6 +1796,7 @@ static void process_discard_bio(struct thin_c *tc, struct bio *bio) * cell will never be granted. */ return; + } tc->pool->process_discard_cell(tc, virt_cell); } -- 2.40.0