[PATCH blktests] src/miniublk: fix logical block size setting

[PATCH blktests] src/miniublk: fix logical block size setting

[Akinobu Mita]

The miniublk always sets the logical block size to 512 bytes when setting
a regular file-backed loop target.
A test fails if the regular file is on a filesystem built on a block
device with a logical block size of 4KB.

$ cd blktests
$ modprobe -r scsi_debug
$ modprobe scsi_debug sector_size=4096 dev_size_mb=2048
$ mkfs.ext4 /dev/sdX
$ mount /dev/sdX results/
$ ./check ublk/003

The logical block size of the ublk block device is set to 512 bytes,
so a request that is not 4KB aligned may occur, and the miniublk will
attempt to process it with direct IO and fail.

The original ublk program already fixed this problem by determining
the logical block size to set based on the block device to which the
target regular file belongs.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 src/miniublk.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/miniublk.c b/src/miniublk.c
index 1c97668..565aa60 100644
--- a/src/miniublk.c
+++ b/src/miniublk.c
@@ -1440,6 +1440,8 @@ static int ublk_loop_tgt_init(struct ublk_dev *dev)
 		p.basic.physical_bs_shift = ilog2(pbs);
 	} else if (S_ISREG(st.st_mode)) {
 		bytes = st.st_size;
+		p.basic.logical_bs_shift = ilog2(st.st_blksize);
+		p.basic.physical_bs_shift = ilog2(st.st_blksize);
 	} else {
 		bytes = 0;
 	}
@@ -1512,6 +1514,8 @@ static int ublk_loop_tgt_recover(struct ublk_dev *dev)
 			return -1;
 	} else if (S_ISREG(st.st_mode)) {
 		bytes = st.st_size;
+		bs = st.st_blksize;
+		pbs = st.st_blksize;
 	} else {
 		bytes = 0;
 	}
-- 
2.34.1

Re: [PATCH blktests] src/miniublk: fix logical block size setting

[Ming Lei]

On Sat, Nov 04, 2023 at 09:17:42PM +0900, Akinobu Mita wrote:
> The miniublk always sets the logical block size to 512 bytes when setting
> a regular file-backed loop target.
> A test fails if the regular file is on a filesystem built on a block
> device with a logical block size of 4KB.
> 
> $ cd blktests
> $ modprobe -r scsi_debug
> $ modprobe scsi_debug sector_size=4096 dev_size_mb=2048
> $ mkfs.ext4 /dev/sdX
> $ mount /dev/sdX results/
> $ ./check ublk/003
> 
> The logical block size of the ublk block device is set to 512 bytes,
> so a request that is not 4KB aligned may occur, and the miniublk will
> attempt to process it with direct IO and fail.
> 
> The original ublk program already fixed this problem by determining
> the logical block size to set based on the block device to which the
> target regular file belongs.
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> ---
>  src/miniublk.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/src/miniublk.c b/src/miniublk.c
> index 1c97668..565aa60 100644
> --- a/src/miniublk.c
> +++ b/src/miniublk.c
> @@ -1440,6 +1440,8 @@ static int ublk_loop_tgt_init(struct ublk_dev *dev)
>  		p.basic.physical_bs_shift = ilog2(pbs);
>  	} else if (S_ISREG(st.st_mode)) {
>  		bytes = st.st_size;
> +		p.basic.logical_bs_shift = ilog2(st.st_blksize);
> +		p.basic.physical_bs_shift = ilog2(st.st_blksize);
>  	} else {
>  		bytes = 0;
>  	}
> @@ -1512,6 +1514,8 @@ static int ublk_loop_tgt_recover(struct ublk_dev *dev)
>  			return -1;
>  	} else if (S_ISREG(st.st_mode)) {
>  		bytes = st.st_size;
> +		bs = st.st_blksize;
> +		pbs = st.st_blksize;
>  	} else {
>  		bytes = 0;

Looks fine,

Reviewed-by: Ming Lei <ming.lei@redhat.com>

Thanks,
Ming

Re: [PATCH blktests] src/miniublk: fix logical block size setting

[Shinichiro Kawasaki]

On Nov 04, 2023 / 21:17, Akinobu Mita wrote:
> The miniublk always sets the logical block size to 512 bytes when setting
> a regular file-backed loop target.
> A test fails if the regular file is on a filesystem built on a block
> device with a logical block size of 4KB.
> 
> $ cd blktests
> $ modprobe -r scsi_debug
> $ modprobe scsi_debug sector_size=4096 dev_size_mb=2048
> $ mkfs.ext4 /dev/sdX
> $ mount /dev/sdX results/
> $ ./check ublk/003
> 
> The logical block size of the ublk block device is set to 512 bytes,
> so a request that is not 4KB aligned may occur, and the miniublk will
> attempt to process it with direct IO and fail.
> 
> The original ublk program already fixed this problem by determining
> the logical block size to set based on the block device to which the
> target regular file belongs.
> 
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

I've applied it. Thanks!