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dm snapshot: allocate a per-target structure for snapshot-origin target

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Allocate a per-target dm_origin structure.  This is a prerequisite for
the next commit ("dm snapshot: do not split read bios sent to
snapshot-origin target") which adds a new member to this structure.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2014-03-14 18:42:12 -04:00 committed by Mike Snitzer
parent 1dd40c3ecd
commit 599cdf3bfb
1 changed files with 37 additions and 20 deletions
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57
drivers/md/dm-snap.c
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@ -2141,6 +2141,10 @@ static int origin_write_extent(struct dm_snapshot *merging_snap,
* Origin: maps a linear range of a device, with hooks for snapshotting.
*/
struct dm_origin {
struct dm_dev *dev;
};
/*
* Construct an origin mapping: <dev_path>
* The context for an origin is merely a 'struct dm_dev *'
@ -2149,41 +2153,54 @@ static int origin_write_extent(struct dm_snapshot *merging_snap,
static int origin_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
int r;
struct dm_dev *dev;
struct dm_origin *o;
if (argc != 1) {
ti->error = "origin: incorrect number of arguments";
return -EINVAL;
}
r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &dev);
if (r) {
ti->error = "Cannot get target device";
return r;
o = kmalloc(sizeof(struct dm_origin), GFP_KERNEL);
if (!o) {
ti->error = "Cannot allocate private origin structure";
r = -ENOMEM;
goto bad_alloc;
}
ti->private = dev;
r = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &o->dev);
if (r) {
ti->error = "Cannot get target device";
goto bad_open;
}
ti->private = o;
ti->num_flush_bios = 1;
return 0;
bad_open:
kfree(o);
bad_alloc:
return r;
}
static void origin_dtr(struct dm_target *ti)
{
struct dm_dev *dev = ti->private;
dm_put_device(ti, dev);
struct dm_origin *o = ti->private;
dm_put_device(ti, o->dev);
kfree(o);
}
static int origin_map(struct dm_target *ti, struct bio *bio)
{
struct dm_dev *dev = ti->private;
bio->bi_bdev = dev->bdev;
struct dm_origin *o = ti->private;
bio->bi_bdev = o->dev->bdev;
if (bio->bi_rw & REQ_FLUSH)
return DM_MAPIO_REMAPPED;
/* Only tell snapshots if this is a write */
return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : DM_MAPIO_REMAPPED;
return (bio_rw(bio) == WRITE) ? do_origin(o->dev, bio) : DM_MAPIO_REMAPPED;
}
/*
@ -2192,15 +2209,15 @@ static int origin_map(struct dm_target *ti, struct bio *bio)
*/
static void origin_resume(struct dm_target *ti)
{
struct dm_dev *dev = ti->private;
struct dm_origin *o = ti->private;
ti->max_io_len = get_origin_minimum_chunksize(dev->bdev);
ti->max_io_len = get_origin_minimum_chunksize(o->dev->bdev);
}
static void origin_status(struct dm_target *ti, status_type_t type,
unsigned status_flags, char *result, unsigned maxlen)
{
struct dm_dev *dev = ti->private;
struct dm_origin *o = ti->private;
switch (type) {
case STATUSTYPE_INFO:
@ -2208,7 +2225,7 @@ static void origin_status(struct dm_target *ti, status_type_t type,
break;
case STATUSTYPE_TABLE:
snprintf(result, maxlen, "%s", dev->name);
snprintf(result, maxlen, "%s", o->dev->name);
break;
}
}
@ -2216,13 +2233,13 @@ static void origin_status(struct dm_target *ti, status_type_t type,
static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
struct bio_vec *biovec, int max_size)
{
struct dm_dev *dev = ti->private;
struct request_queue *q = bdev_get_queue(dev->bdev);
struct dm_origin *o = ti->private;
struct request_queue *q = bdev_get_queue(o->dev->bdev);
if (!q->merge_bvec_fn)
return max_size;
bvm->bi_bdev = dev->bdev;
bvm->bi_bdev = o->dev->bdev;
return min(max_size, q->merge_bvec_fn(q, bvm, biovec));
}
@ -2230,9 +2247,9 @@ static int origin_merge(struct dm_target *ti, struct bvec_merge_data *bvm,
static int origin_iterate_devices(struct dm_target *ti,
iterate_devices_callout_fn fn, void *data)
{
struct dm_dev *dev = ti->private;
struct dm_origin *o = ti->private;
return fn(ti, dev, 0, ti->len, data);
return fn(ti, o->dev, 0, ti->len, data);
}
static struct target_type origin_target = {