[PATCH 01/15] dm: support ioctls on mapped devices

From: Alasdair G Kergon
Date: Wed Jun 21 2006 - 15:30:11 EST


From: Milan Broz <mbroz@xxxxxxxxxx>

Extend the core device-mapper infrastructure to accept arbitrary ioctls
on a mapped device provided that it has exactly one target and it is
capable of supporting ioctls.

[We can't use unlocked_ioctl because we need 'inode': 'file' might be NULL.
Is it worth changing this?]

Signed-off-by: Milan Broz <mbroz@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>

Index: linux-2.6.17/drivers/md/dm.c
===================================================================
--- linux-2.6.17.orig/drivers/md/dm.c 2006-06-21 14:45:28.000000000 +0100
+++ linux-2.6.17/drivers/md/dm.c 2006-06-21 18:32:01.000000000 +0100
@@ -20,6 +20,7 @@
#include <linux/idr.h>
#include <linux/hdreg.h>
#include <linux/blktrace_api.h>
+#include <linux/smp_lock.h>

static const char *_name = DM_NAME;

@@ -257,6 +258,45 @@ static int dm_blk_getgeo(struct block_de
return dm_get_geometry(md, geo);
}

+static int dm_blk_ioctl(struct inode *inode, struct file *file,
+ unsigned int cmd, unsigned long arg)
+{
+ struct mapped_device *md;
+ struct dm_table *map;
+ struct dm_target *tgt;
+ int r = -ENOTTY;
+
+ /* We don't really need this lock, but we do need 'inode'. */
+ unlock_kernel();
+
+ md = inode->i_bdev->bd_disk->private_data;
+
+ map = dm_get_table(md);
+
+ if (!map || !dm_table_get_size(map))
+ goto out;
+
+ /* We only support devices that have a single target */
+ if (dm_table_get_num_targets(map) != 1)
+ goto out;
+
+ tgt = dm_table_get_target(map, 0);
+
+ if (dm_suspended(md)) {
+ r = -EAGAIN;
+ goto out;
+ }
+
+ if (tgt->type->ioctl)
+ r = tgt->type->ioctl(tgt, inode, file, cmd, arg);
+
+out:
+ dm_table_put(map);
+
+ lock_kernel();
+ return r;
+}
+
static inline struct dm_io *alloc_io(struct mapped_device *md)
{
return mempool_alloc(md->io_pool, GFP_NOIO);
@@ -1348,6 +1388,7 @@ int dm_suspended(struct mapped_device *m
static struct block_device_operations dm_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
+ .ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.owner = THIS_MODULE
};
Index: linux-2.6.17/include/linux/device-mapper.h
===================================================================
--- linux-2.6.17.orig/include/linux/device-mapper.h 2006-06-21 14:45:28.000000000 +0100
+++ linux-2.6.17/include/linux/device-mapper.h 2006-06-21 17:45:05.000000000 +0100
@@ -61,6 +61,10 @@ typedef int (*dm_status_fn) (struct dm_t

typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);

+typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
+ struct file *filp, unsigned int cmd,
+ unsigned long arg);
+
void dm_error(const char *message);

/*
@@ -88,6 +92,7 @@ struct target_type {
dm_resume_fn resume;
dm_status_fn status;
dm_message_fn message;
+ dm_ioctl_fn ioctl;
};

struct io_restrictions {
Index: linux-2.6.17/include/linux/dm-ioctl.h
===================================================================
--- linux-2.6.17.orig/include/linux/dm-ioctl.h 2006-06-21 14:45:28.000000000 +0100
+++ linux-2.6.17/include/linux/dm-ioctl.h 2006-06-21 17:44:41.000000000 +0100
@@ -285,9 +285,9 @@ typedef char ioctl_struct[308];
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)

#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 6
+#define DM_VERSION_MINOR 7
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2006-02-17)"
+#define DM_VERSION_EXTRA "-ioctl (2006-05-30)"

/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
-
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