From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: [PATCH 2/4 v2] brd: Add getgeo to block ops Date: Thu, 07 Aug 2014 17:03:08 +0300 Message-ID: <53E3871C.4020008@plexistor.com> References: <53E21125.9080308@plexistor.com> <53E211D9.7030102@plexistor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: linux-fsdevel To: Jens Axboe , Ross Zwisler , Matthew Wilcox , linux-kernel Return-path: In-Reply-To: <53E211D9.7030102@plexistor.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: Boaz Harrosh Some programs like fdisk, require HDIO_GETGEO to work, which requires we implement getgeo. We set all hd_geometry members to 1, because this way fdisk math will not try its crazy geometry math and get stuff totally wrong. I was trying to get some values that will make fdisk Want to align first sector on 4K (like 8, 16, 20, ... sectors) but nothing worked, I searched the net the math is not your regular simple multiplication at all. If you managed to get these magic values please tell me. I would love to solve this. But for now we use 4k physical_sector for fixing fdisk alignment issues, and setting these here to something that will not make fdisk serve us with crazy numbers. Signed-off-by: Boaz Harrosh --- drivers/block/brd.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index a10a0a9..8be3747 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -19,6 +19,7 @@ #include #include #include +#include #include @@ -424,6 +425,23 @@ static int brd_ioctl(struct block_device *bdev, fmode_t mode, return error; } +static int brd_getgeo(struct block_device *bd, struct hd_geometry *geo) +{ + /* Just tell fdisk to get out of the way. The math here is so + * convoluted and does not make any sense at all. With all 1s + * The math just gets out of the way. + * NOTE: I was trying to get some values that will make fdisk + * Want to align first sector on 4K (like 8, 16, 20, ... sectors) but + * nothing worked, I searched the net the math is not your regular + * simple multiplication at all. If you managed to get these please + * fix here. For now we use 4k physical sectors for this + */ + geo->heads = 1; + geo->sectors = 1; + geo->cylinders = 1; + return 0; +} + static const struct block_device_operations brd_fops = { .owner = THIS_MODULE, .rw_page = brd_rw_page, @@ -431,6 +449,7 @@ static const struct block_device_operations brd_fops = { #ifdef CONFIG_BLK_DEV_XIP .direct_access = brd_direct_access, #endif + .getgeo = brd_getgeo, }; /* -- 1.9.3