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[83.162.234.235]) by smtp.gmail.com with ESMTPSA id d133sm8887008wmc.27.2020.04.29.07.03.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2020 07:03:49 -0700 (PDT) From: Martijn Coenen To: axboe@kernel.dk, hch@lst.de, ming.lei@redhat.com Cc: narayan@google.com, zezeozue@google.com, kernel-team@android.com, maco@google.com, bvanassche@acm.org, Chaitanya.Kulkarni@wdc.com, jaegeuk@kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Martijn Coenen Subject: [PATCH v4 04/10] loop: Refactor loop_set_status() size calculation Date: Wed, 29 Apr 2020 16:03:35 +0200 Message-Id: <20200429140341.13294-5-maco@android.com> X-Mailer: git-send-email 2.26.2.303.gf8c07b1a785-goog In-Reply-To: <20200429140341.13294-1-maco@android.com> References: <20200429140341.13294-1-maco@android.com> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org figure_loop_size() calculates the loop size based on the passed in parameters, but at the same time it updates the offset and sizelimit parameters in the loop device configuration. That is a somewhat unexpected side effect of a function with this name, and it is only only needed by one of the two callers of this function - loop_set_status(). Move the lo_offset and lo_sizelimit assignment back into loop_set_status(), and use the newly factored out functions to validate and apply the newly calculated size. This allows us to get rid of figure_loop_size() in a follow-up commit. Signed-off-by: Martijn Coenen Reviewed-by: Christoph Hellwig --- drivers/block/loop.c | 44 +++++++++++++++++++++++--------------------- 1 file changed, 23 insertions(+), 21 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 8f3194c2b8aa..9f5913879921 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -268,11 +268,6 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit) if (err) return err; - if (lo->lo_offset != offset) - lo->lo_offset = offset; - if (lo->lo_sizelimit != sizelimit) - lo->lo_sizelimit = sizelimit; - loop_set_size(lo, size); return 0; @@ -1294,6 +1289,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) kuid_t uid = current_uid(); struct block_device *bdev; bool partscan = false; + bool size_changed = false; + loff_t validated_size; err = mutex_lock_killable(&loop_ctl_mutex); if (err) @@ -1315,6 +1312,13 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if (lo->lo_offset != info->lo_offset || lo->lo_sizelimit != info->lo_sizelimit) { + loff_t size = get_size(info->lo_offset, info->lo_sizelimit, + lo->lo_backing_file); + err = loop_validate_size(size); + if (err) + goto out_unlock; + size_changed = true; + validated_size = size; sync_blockdev(lo->lo_device); kill_bdev(lo->lo_device); } @@ -1322,6 +1326,15 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) /* I/O need to be drained during transfer transition */ blk_mq_freeze_queue(lo->lo_queue); + if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) { + /* If any pages were dirtied after kill_bdev(), try again */ + err = -EAGAIN; + pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", + __func__, lo->lo_number, lo->lo_file_name, + lo->lo_device->bd_inode->i_mapping->nrpages); + goto out_unfreeze; + } + err = loop_release_xfer(lo); if (err) goto out_unfreeze; @@ -1345,22 +1358,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) if (err) goto out_unfreeze; - if (lo->lo_offset != info->lo_offset || - lo->lo_sizelimit != info->lo_sizelimit) { - /* kill_bdev should have truncated all the pages */ - if (lo->lo_device->bd_inode->i_mapping->nrpages) { - err = -EAGAIN; - pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n", - __func__, lo->lo_number, lo->lo_file_name, - lo->lo_device->bd_inode->i_mapping->nrpages); - goto out_unfreeze; - } - if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) { - err = -EFBIG; - goto out_unfreeze; - } - } - + lo->lo_offset = info->lo_offset; + lo->lo_sizelimit = info->lo_sizelimit; memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE); memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE); lo->lo_file_name[LO_NAME_SIZE-1] = 0; @@ -1384,6 +1383,9 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info) lo->lo_key_owner = uid; } + if (size_changed) + loop_set_size(lo, validated_size); + loop_config_discard(lo); /* update dio if lo_offset or transfer is changed */