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rbd: define rbd_dev_unprobe() 

Define a new function rbd_dev_unprobe() which undoes state changes
that occur from calling rbd_dev_v1_probe() or rbd_dev_v2_probe().
Note that this is a superset of rbd_header_free(), which is now
getting removed (it seems to have been used improperly anyway).

Flesh out rbd_dev_image_release() so it undoes exactly what
rbd_dev_image_probe() does.

This means that:
    - rbd_dev_device_release() gets called when the last device
      reference gets dropped;
    - that undoes everything done by the rbd_dev_device_setup() call
      at the end of rbd_dev_image_probe() (and nothing more), ending
      by calling rbd_dev_image_release(); and
    - rbd_dev_image_release() undoes everything else done by
      rbd_dev_image_probe() (and this includes a call to
      rbd_dev_unprobe().

This means the image and device portions of an rbd device are fairly
cleanly separated now, so error paths should be a little easier to
verify than they used to be.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-04-28 23:32:34 -05:00 committed by Sage Weil
parent 200a6a8be5
commit 6fd48b3be9
1 changed files with 38 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
drivers/block/rbd.c
View File

@ -900,18 +900,6 @@ static void rbd_dev_clear_mapping(struct rbd_device *rbd_dev)
rbd_dev->mapping.read_only = true;
}
static void rbd_header_free(struct rbd_image_header *header)
{
kfree(header->object_prefix);
header->object_prefix = NULL;
kfree(header->snap_sizes);
header->snap_sizes = NULL;
kfree(header->snap_names);
header->snap_names = NULL;
rbd_snap_context_put(header->snapc);
header->snapc = NULL;
}
static const char *rbd_segment_name(struct rbd_device *rbd_dev, u64 offset)
{
char *name;
@ -4588,6 +4576,27 @@ out:
return ret;
}
/* Undo whatever state changes are made by v1 or v2 image probe */
static void rbd_dev_unprobe(struct rbd_device *rbd_dev)
{
struct rbd_image_header *header;
rbd_dev_remove_parent(rbd_dev);
rbd_spec_put(rbd_dev->parent_spec);
rbd_dev->parent_spec = NULL;
rbd_dev->parent_overlap = 0;
/* Free dynamic fields from the header, then zero it out */
header = &rbd_dev->header;
rbd_snap_context_put(header->snapc);
kfree(header->snap_sizes);
kfree(header->snap_names);
kfree(header->object_prefix);
memset(header, 0, sizeof (*header));
}
static int rbd_dev_v1_probe(struct rbd_device *rbd_dev)
{
int ret;
@ -4809,10 +4818,19 @@ static int rbd_dev_header_name(struct rbd_device *rbd_dev)
static void rbd_dev_image_release(struct rbd_device *rbd_dev)
{
rbd_header_free(&rbd_dev->header);
rbd_assert(rbd_dev->rbd_client != NULL);
rbd_spec_put(rbd_dev->parent_spec);
int ret;
rbd_remove_all_snaps(rbd_dev);
rbd_dev_unprobe(rbd_dev);
ret = rbd_dev_header_watch_sync(rbd_dev, 0);
if (ret)
rbd_warn(rbd_dev, "failed to cancel watch event (%d)\n", ret);
kfree(rbd_dev->header_name);
rbd_dev->header_name = NULL;
rbd_dev->image_format = 0;
kfree(rbd_dev->spec->image_id);
rbd_dev->spec->image_id = NULL;
rbd_dev_destroy(rbd_dev);
}
@ -4854,7 +4872,7 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev)
ret = rbd_dev_snaps_update(rbd_dev);
if (ret)
goto err_out_watch;
goto err_out_probe;
ret = rbd_dev_spec_update(rbd_dev);
if (ret)
@ -4865,15 +4883,13 @@ static int rbd_dev_image_probe(struct rbd_device *rbd_dev)
goto err_out_snaps;
ret = rbd_dev_device_setup(rbd_dev);
if (ret)
goto err_out_parent;
if (!ret)
return 0;
return ret;
err_out_parent:
rbd_dev_remove_parent(rbd_dev);
rbd_header_free(&rbd_dev->header);
err_out_snaps:
rbd_remove_all_snaps(rbd_dev);
err_out_probe:
rbd_dev_unprobe(rbd_dev);
err_out_watch:
tmp = rbd_dev_header_watch_sync(rbd_dev, 0);
if (tmp)
@ -5005,7 +5021,6 @@ static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
struct rbd_device *first = rbd_dev;
struct rbd_device *second = first->parent;
struct rbd_device *third;
int ret;
/*
* Follow to the parent with no grandparent and
@ -5016,11 +5031,6 @@ static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
second = third;
}
rbd_assert(second);
ret = rbd_dev_header_watch_sync(rbd_dev, 0);
if (ret)
rbd_warn(rbd_dev,
"failed to cancel watch event (%d)\n", ret);
rbd_remove_all_snaps(second);
rbd_bus_del_dev(second);
first->parent = NULL;
first->parent_overlap = 0;
@ -5065,19 +5075,7 @@ static ssize_t rbd_remove(struct bus_type *bus,
spin_unlock_irq(&rbd_dev->lock);
if (ret < 0)
goto done;
ret = rbd_dev_header_watch_sync(rbd_dev, 0);
if (ret) {
rbd_warn(rbd_dev, "failed to cancel watch event (%d)\n", ret);
clear_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags);
smp_mb();
return ret;
}
ret = count;
rbd_dev_remove_parent(rbd_dev);
rbd_remove_all_snaps(rbd_dev);
rbd_bus_del_dev(rbd_dev);
module_put(THIS_MODULE);
done: