Currently the loop driver just simulates 512-byte blocks. When
creating bootable images for virtual machines it might be required
to use a different physical blocksize (eg 4k for S/390 DASD), as
the some bootloaders (like lilo or zipl for S/390) need to know
the physical block addresses of the kernel and initrd.
This patchset extends the current LOOP_SET_STATUS64 ioctl to
set the logical and physical blocksize by re-using the existing
'init' fields, which are currently unused.
As usual, comments and reviews are welcome.
Changes to v1:
- Move LO_FLAGS_BLOCKSIZE definition
- Reshuffle patches
Hannes Reinecke (4):
loop: Remove unused 'bdev' argument from loop_set_capacity
loop: Enable correct physical blocksize
loop: Add 'lo_logical_blocksize'
loop: Pass logical blocksize in 'lo_init[0]' ioctl field
drivers/block/loop.c | 35 ++++++++++++++++++++++++++++++-----
drivers/block/loop.h | 1 +
include/uapi/linux/loop.h | 1 +
3 files changed, 32 insertions(+), 5 deletions(-)
--
1.8.4.5
Signed-off-by: Hannes Reinecke <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
drivers/block/loop.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f7a4c9d..b9e12a0 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1130,7 +1130,7 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
return err;
}
-static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev)
+static int loop_set_capacity(struct loop_device *lo)
{
if (unlikely(lo->lo_state != Lo_bound))
return -ENXIO;
@@ -1179,7 +1179,7 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
case LOOP_SET_CAPACITY:
err = -EPERM;
if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
- err = loop_set_capacity(lo, bdev);
+ err = loop_set_capacity(lo);
break;
default:
err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
--
1.8.4.5
When running on files the physical blocksize is actually 4k,
so we should be announcing it as such. This is enabled with
a new LO_FLAGS_BLOCKSIZE flag value to the existing ioctl.
Signed-off-by: Hannes Reinecke <[email protected]>
---
drivers/block/loop.c | 9 ++++++++-
include/uapi/linux/loop.h | 1 +
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b9e12a0..fce13bd 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -177,6 +177,8 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
lo->lo_offset = offset;
if (lo->lo_sizelimit != sizelimit)
lo->lo_sizelimit = sizelimit;
+ if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
+ blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
set_capacity(lo->lo_disk, x);
bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
/* let user-space know about the new size */
@@ -758,7 +760,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
lo->lo_blocksize = lo_blocksize;
lo->lo_device = bdev;
- lo->lo_flags = lo_flags;
+ lo->lo_flags |= lo_flags;
lo->lo_backing_file = file;
lo->transfer = NULL;
lo->ioctl = NULL;
@@ -769,6 +771,8 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
blk_queue_flush(lo->lo_queue, REQ_FLUSH);
+ if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
+ blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
loop_sysfs_init(lo);
@@ -951,6 +955,9 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
if (err)
return err;
+ if (info->lo_flags & LO_FLAGS_BLOCKSIZE)
+ lo->lo_flags |= LO_FLAGS_BLOCKSIZE;
+
if (lo->lo_offset != info->lo_offset ||
lo->lo_sizelimit != info->lo_sizelimit)
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
index e0cecd2..caec9d3 100644
--- a/include/uapi/linux/loop.h
+++ b/include/uapi/linux/loop.h
@@ -21,6 +21,7 @@ enum {
LO_FLAGS_READ_ONLY = 1,
LO_FLAGS_AUTOCLEAR = 4,
LO_FLAGS_PARTSCAN = 8,
+ LO_FLAGS_BLOCKSIZE = 16,
};
#include <asm/posix_types.h> /* for __kernel_old_dev_t */
--
1.8.4.5
Add a new field 'lo_logical_blocksize' to hold the logical
blocksize of the loop device.
Signed-off-by: Hannes Reinecke <[email protected]>
---
drivers/block/loop.c | 14 +++++++++++---
drivers/block/loop.h | 1 +
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index fce13bd..321f296 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -177,8 +177,11 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
lo->lo_offset = offset;
if (lo->lo_sizelimit != sizelimit)
lo->lo_sizelimit = sizelimit;
- if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
+ if (lo->lo_flags & LO_FLAGS_BLOCKSIZE) {
blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
+ blk_queue_logical_block_size(lo->lo_queue,
+ lo->lo_logical_blocksize);
+ }
set_capacity(lo->lo_disk, x);
bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
/* let user-space know about the new size */
@@ -666,6 +669,7 @@ static void loop_config_discard(struct loop_device *lo)
struct file *file = lo->lo_backing_file;
struct inode *inode = file->f_mapping->host;
struct request_queue *q = lo->lo_queue;
+ int lo_bits = blksize_bits(lo->lo_logical_blocksize);
/*
* We use punch hole to reclaim the free space used by the
@@ -685,7 +689,7 @@ static void loop_config_discard(struct loop_device *lo)
q->limits.discard_granularity = inode->i_sb->s_blocksize;
q->limits.discard_alignment = 0;
- q->limits.max_discard_sectors = UINT_MAX >> 9;
+ q->limits.max_discard_sectors = UINT_MAX >> lo_bits;
q->limits.discard_zeroes_data = 1;
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
}
@@ -759,6 +763,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
set_device_ro(bdev, (lo_flags & LO_FLAGS_READ_ONLY) != 0);
lo->lo_blocksize = lo_blocksize;
+ lo->lo_logical_blocksize = 512;
lo->lo_device = bdev;
lo->lo_flags |= lo_flags;
lo->lo_backing_file = file;
@@ -771,8 +776,11 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
blk_queue_flush(lo->lo_queue, REQ_FLUSH);
- if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
+ if (lo->lo_flags & LO_FLAGS_BLOCKSIZE) {
blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
+ blk_queue_logical_block_size(lo->lo_queue,
+ lo->lo_logical_blocksize);
+ }
set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
loop_sysfs_init(lo);
diff --git a/drivers/block/loop.h b/drivers/block/loop.h
index 25e8997..93af885 100644
--- a/drivers/block/loop.h
+++ b/drivers/block/loop.h
@@ -49,6 +49,7 @@ struct loop_device {
struct file * lo_backing_file;
struct block_device *lo_device;
unsigned lo_blocksize;
+ unsigned lo_logical_blocksize;
void *key_data;
gfp_t old_gfp_mask;
--
1.8.4.5
The current LOOP_SET_STATUS64 ioctl has two unused fields
'init[2]', which can be used in conjunction with the
LO_FLAGS_BLOCKSIZE flag to pass in the new logical blocksize.
Signed-off-by: Hannes Reinecke <[email protected]>
---
drivers/block/loop.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 321f296..3d2ee0f 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -963,11 +963,21 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
if (err)
return err;
- if (info->lo_flags & LO_FLAGS_BLOCKSIZE)
+ if (info->lo_flags & LO_FLAGS_BLOCKSIZE) {
lo->lo_flags |= LO_FLAGS_BLOCKSIZE;
+ if ((info->lo_init[0] != 512) &&
+ (info->lo_init[0] != 1024) &&
+ (info->lo_init[0] != 2048) &&
+ (info->lo_init[0] != 4096))
+ return -EINVAL;
+ if (info->lo_init[0] > lo->lo_blocksize)
+ return -EINVAL;
+ lo->lo_logical_blocksize = info->lo_init[0];
+ }
if (lo->lo_offset != info->lo_offset ||
- lo->lo_sizelimit != info->lo_sizelimit)
+ lo->lo_sizelimit != info->lo_sizelimit ||
+ lo->lo_flags & LO_FLAGS_BLOCKSIZE)
if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
return -EFBIG;
--
1.8.4.5
On Fri, Aug 7, 2015 at 4:54 AM, Hannes Reinecke <[email protected]> wrote:
> When running on files the physical blocksize is actually 4k,
> so we should be announcing it as such. This is enabled with
> a new LO_FLAGS_BLOCKSIZE flag value to the existing ioctl.
>
> Signed-off-by: Hannes Reinecke <[email protected]>
> ---
> drivers/block/loop.c | 9 ++++++++-
> include/uapi/linux/loop.h | 1 +
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index b9e12a0..fce13bd 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -177,6 +177,8 @@ figure_loop_size(struct loop_device *lo, loff_t offset, loff_t sizelimit)
> lo->lo_offset = offset;
> if (lo->lo_sizelimit != sizelimit)
> lo->lo_sizelimit = sizelimit;
> + if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
> + blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
> set_capacity(lo->lo_disk, x);
> bd_set_size(bdev, (loff_t)get_capacity(bdev->bd_disk) << 9);
> /* let user-space know about the new size */
> @@ -758,7 +760,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
>
> lo->lo_blocksize = lo_blocksize;
> lo->lo_device = bdev;
> - lo->lo_flags = lo_flags;
> + lo->lo_flags |= lo_flags;
lo->lo_flags is cleared in loop_clr_fd(), and set_status() can only
be done when loop's state is bound, so why do you want to
keep previous zero flag?
> lo->lo_backing_file = file;
> lo->transfer = NULL;
> lo->ioctl = NULL;
> @@ -769,6 +771,8 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
> if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
> blk_queue_flush(lo->lo_queue, REQ_FLUSH);
>
> + if (lo->lo_flags & LO_FLAGS_BLOCKSIZE)
> + blk_queue_physical_block_size(lo->lo_queue, lo->lo_blocksize);
> set_capacity(lo->lo_disk, size);
> bd_set_size(bdev, size << 9);
> loop_sysfs_init(lo);
> @@ -951,6 +955,9 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
> if (err)
> return err;
>
> + if (info->lo_flags & LO_FLAGS_BLOCKSIZE)
> + lo->lo_flags |= LO_FLAGS_BLOCKSIZE;
> +
> if (lo->lo_offset != info->lo_offset ||
> lo->lo_sizelimit != info->lo_sizelimit)
> if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit))
> diff --git a/include/uapi/linux/loop.h b/include/uapi/linux/loop.h
> index e0cecd2..caec9d3 100644
> --- a/include/uapi/linux/loop.h
> +++ b/include/uapi/linux/loop.h
> @@ -21,6 +21,7 @@ enum {
> LO_FLAGS_READ_ONLY = 1,
> LO_FLAGS_AUTOCLEAR = 4,
> LO_FLAGS_PARTSCAN = 8,
> + LO_FLAGS_BLOCKSIZE = 16,
> };
>
> #include <asm/posix_types.h> /* for __kernel_old_dev_t */
> --
> 1.8.4.5
>
--
Ming Lei