Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
dm: Allow .prepare_ioctl to handle ioctls directly
This adds a 'bool *forward' parameter to .prepare_ioctl, which allows
device mapper targets to accept ioctls to themselves instead of the
underlying device. If the target already fully handled the ioctl, it
sets *forward to false and device mapper won't forward it to the
underlying device any more.
In order for targets to actually know what the ioctl is about and how to
handle it, pass also cmd and arg.
As long as targets restrict themselves to interpreting ioctls of type
DM_IOCTL, this is a backwards compatible change because previously, any
such ioctl would have been passed down through all device mapper layers
until it reached a device that can't understand the ioctl and would
return an error.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
authored by
Kevin Wolf
and committed by
Mikulas Patocka
4862c886
13e79076
+44
-16
+3
-1
drivers/md/dm-dust.c
+3
-1
drivers/md/dm-dust.c
···
534
534
}
535
535
}
536
536
537
-
static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
537
+
static int dust_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
538
+
unsigned int cmd, unsigned long arg,
539
+
bool *forward)
538
540
{
539
541
struct dust_device *dd = ti->private;
540
542
struct dm_dev *dev = dd->dev;
+2
-1
drivers/md/dm-ebs-target.c
+2
-1
drivers/md/dm-ebs-target.c
···
415
415
}
416
416
}
417
417
418
-
static int ebs_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
418
+
static int ebs_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
419
+
unsigned int cmd, unsigned long arg, bool *forward)
419
420
{
420
421
struct ebs_c *ec = ti->private;
421
422
struct dm_dev *dev = ec->dev;
+3
-1
drivers/md/dm-flakey.c
+3
-1
drivers/md/dm-flakey.c
···
648
648
}
649
649
}
650
650
651
-
static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
651
+
static int flakey_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
652
+
unsigned int cmd, unsigned long arg,
653
+
bool *forward)
652
654
{
653
655
struct flakey_c *fc = ti->private;
654
656
+3
-1
drivers/md/dm-linear.c
+3
-1
drivers/md/dm-linear.c
···
119
119
}
120
120
}
121
121
122
-
static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
122
+
static int linear_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
123
+
unsigned int cmd, unsigned long arg,
124
+
bool *forward)
123
125
{
124
126
struct linear_c *lc = ti->private;
125
127
struct dm_dev *dev = lc->dev;
+3
-1
drivers/md/dm-log-writes.c
+3
-1
drivers/md/dm-log-writes.c
···
818
818
}
819
819
820
820
static int log_writes_prepare_ioctl(struct dm_target *ti,
821
-
struct block_device **bdev)
821
+
struct block_device **bdev,
822
+
unsigned int cmd, unsigned long arg,
823
+
bool *forward)
822
824
{
823
825
struct log_writes_c *lc = ti->private;
824
826
struct dm_dev *dev = lc->dev;
+3
-1
drivers/md/dm-mpath.c
+3
-1
drivers/md/dm-mpath.c
···
2022
2022
}
2023
2023
2024
2024
static int multipath_prepare_ioctl(struct dm_target *ti,
2025
-
struct block_device **bdev)
2025
+
struct block_device **bdev,
2026
+
unsigned int cmd, unsigned long arg,
2027
+
bool *forward)
2026
2028
{
2027
2029
struct multipath *m = ti->private;
2028
2030
struct pgpath *pgpath;
+3
-1
drivers/md/dm-switch.c
+3
-1
drivers/md/dm-switch.c
···
517
517
*
518
518
* Passthrough all ioctls to the path for sector 0
519
519
*/
520
-
static int switch_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
520
+
static int switch_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
521
+
unsigned int cmd, unsigned long arg,
522
+
bool *forward)
521
523
{
522
524
struct switch_ctx *sctx = ti->private;
523
525
unsigned int path_nr;
+3
-1
drivers/md/dm-verity-target.c
+3
-1
drivers/md/dm-verity-target.c
···
994
994
}
995
995
}
996
996
997
-
static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
997
+
static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
998
+
unsigned int cmd, unsigned long arg,
999
+
bool *forward)
998
1000
{
999
1001
struct dm_verity *v = ti->private;
1000
1002
+2
-1
drivers/md/dm-zoned-target.c
+2
-1
drivers/md/dm-zoned-target.c
···
1015
1015
/*
1016
1016
* Pass on ioctl to the backend device.
1017
1017
*/
1018
-
static int dmz_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
1018
+
static int dmz_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
1019
+
unsigned int cmd, unsigned long arg, bool *forward)
1019
1020
{
1020
1021
struct dmz_target *dmz = ti->private;
1021
1022
struct dmz_dev *dev = &dmz->dev[0];
+11
-6
drivers/md/dm.c
+11
-6
drivers/md/dm.c
···
411
411
}
412
412
413
413
static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
414
-
struct block_device **bdev)
414
+
struct block_device **bdev, unsigned int cmd,
415
+
unsigned long arg, bool *forward)
415
416
{
416
417
struct dm_target *ti;
417
418
struct dm_table *map;
···
435
434
if (dm_suspended_md(md))
436
435
return -EAGAIN;
437
436
438
-
r = ti->type->prepare_ioctl(ti, bdev);
439
-
if (r == -ENOTCONN && !fatal_signal_pending(current)) {
437
+
r = ti->type->prepare_ioctl(ti, bdev, cmd, arg, forward);
438
+
if (r == -ENOTCONN && *forward && !fatal_signal_pending(current)) {
440
439
dm_put_live_table(md, *srcu_idx);
441
440
fsleep(10000);
442
441
goto retry;
···
455
454
{
456
455
struct mapped_device *md = bdev->bd_disk->private_data;
457
456
int r, srcu_idx;
457
+
bool forward = true;
458
458
459
-
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
460
-
if (r < 0)
459
+
r = dm_prepare_ioctl(md, &srcu_idx, &bdev, cmd, arg, &forward);
460
+
if (!forward || r < 0)
461
461
goto out;
462
462
463
463
if (r > 0) {
···
3632
3630
struct mapped_device *md = bdev->bd_disk->private_data;
3633
3631
const struct pr_ops *ops;
3634
3632
int r, srcu_idx;
3633
+
bool forward = true;
3635
3634
3636
-
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
3635
+
/* Not a real ioctl, but targets must not interpret non-DM ioctls */
3636
+
r = dm_prepare_ioctl(md, &srcu_idx, &bdev, 0, 0, &forward);
3637
3637
if (r < 0)
3638
3638
goto out;
3639
+
WARN_ON_ONCE(!forward);
3639
3640
3640
3641
ops = bdev->bd_disk->fops->pr_ops;
3641
3642
if (ops && ops->pr_clear)
+8
-1
include/linux/device-mapper.h
+8
-1
include/linux/device-mapper.h
···
93
93
typedef int (*dm_message_fn) (struct dm_target *ti, unsigned int argc, char **argv,
94
94
char *result, unsigned int maxlen);
95
95
96
-
typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev);
96
+
/*
97
+
* Called with *forward == true. If it remains true, the ioctl should be
98
+
* forwarded to bdev. If it is reset to false, the target already fully handled
99
+
* the ioctl and the return value is the return value for the whole ioctl.
100
+
*/
101
+
typedef int (*dm_prepare_ioctl_fn) (struct dm_target *ti, struct block_device **bdev,
102
+
unsigned int cmd, unsigned long arg,
103
+
bool *forward);
97
104
98
105
#ifdef CONFIG_BLK_DEV_ZONED
99
106
typedef int (*dm_report_zones_fn) (struct dm_target *ti,