Several fields in a struct rbd_dev are related to what is mapped, as
opposed to the actual base rbd image. If the base image is mapped
these are almost unneeded, but if a snapshot is mapped they describe
information about that snapshot.
In some contexts this can be a little bit confusing. So group these
mapping-related field into a structure to make it clear what they
are describing.
This also includes a minor change that rearranges the fields in the
in-core image header structure so that invariant fields are at the
top, followed by those that change.
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
drivers/block/rbd.c | 83
++++++++++++++++++++++++++++-----------------------
1 file changed, 45 insertions(+), 38 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index eb6b772..dff6210 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -81,13 +81,15 @@
* block device image metadata (in-memory version)
*/
struct rbd_image_header {
- u64 image_size;
+ /* These four fields never change for a given rbd image */
char *object_prefix;
__u8 obj_order;
__u8 crypt_type;
__u8 comp_type;
- struct ceph_snap_context *snapc;
+ /* The remaining fields need to be updated occasionally */
+ u64 image_size;
+ struct ceph_snap_context *snapc;
char *snap_names;
u64 *snap_sizes;
@@ -146,6 +148,13 @@ struct rbd_snap {
u64 id;
};
+struct rbd_mapping {
+ char *snap_name;
+ u64 snap_id;
+ bool snap_exists;
+ bool read_only;
+};
+
/*
* a single device
*/
@@ -174,13 +183,8 @@ struct rbd_device {
/* protects updating the header */
struct rw_semaphore header_rwsem;
- /* name of the snapshot this device reads from */
- char *snap_name;
- /* id of the snapshot this device reads from */
- u64 snap_id; /* current snapshot id */
- /* whether the snap_id this device reads from still exists */
- bool snap_exists;
- bool read_only;
+
+ struct rbd_mapping mapping;
struct list_head node;
@@ -261,11 +265,11 @@ static int rbd_open(struct block_device *bdev,
fmode_t mode)
{
struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
- if ((mode & FMODE_WRITE) && rbd_dev->read_only)
+ if ((mode & FMODE_WRITE) && rbd_dev->mapping.read_only)
return -EROFS;
rbd_get_dev(rbd_dev);
- set_device_ro(bdev, rbd_dev->read_only);
+ set_device_ro(bdev, rbd_dev->mapping.read_only);
return 0;
}
@@ -375,7 +379,7 @@ enum {
static match_table_t rbd_opts_tokens = {
/* int args above */
/* string args above */
- {Opt_read_only, "read_only"},
+ {Opt_read_only, "mapping.read_only"},
{Opt_read_only, "ro"}, /* Alternate spelling */
{Opt_read_write, "read_write"},
{Opt_read_write, "rw"}, /* Alternate spelling */
@@ -583,13 +587,13 @@ static int rbd_header_from_disk(struct
rbd_image_header *header,
header->snap_sizes = NULL;
}
- header->image_size = le64_to_cpu(ondisk->image_size);
header->obj_order = ondisk->options.order;
header->crypt_type = ondisk->options.crypt_type;
header->comp_type = ondisk->options.comp_type;
/* Allocate and fill in the snapshot context */
+ header->image_size = le64_to_cpu(ondisk->image_size);
size = sizeof (struct ceph_snap_context);
size += snap_count * sizeof (header->snapc->snaps[0]);
header->snapc = kzalloc(size, GFP_KERNEL);
@@ -645,23 +649,24 @@ static int rbd_header_set_snap(struct rbd_device
*rbd_dev, u64 *size)
down_write(&rbd_dev->header_rwsem);
- if (!memcmp(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
+ if (!memcmp(rbd_dev->mapping.snap_name, RBD_SNAP_HEAD_NAME,
sizeof (RBD_SNAP_HEAD_NAME))) {
- rbd_dev->snap_id = CEPH_NOSNAP;
- rbd_dev->snap_exists = false;
- rbd_dev->read_only = rbd_dev->rbd_opts.read_only;
+ rbd_dev->mapping.snap_id = CEPH_NOSNAP;
+ rbd_dev->mapping.snap_exists = false;
+ rbd_dev->mapping.read_only = rbd_dev->rbd_opts.read_only;
if (size)
*size = rbd_dev->header.image_size;
} else {
u64 snap_id = 0;
- ret = snap_by_name(&rbd_dev->header, rbd_dev->snap_name,
+ ret = snap_by_name(&rbd_dev->header,
+ rbd_dev->mapping.snap_name,
&snap_id, size);
if (ret < 0)
goto done;
- rbd_dev->snap_id = snap_id;
- rbd_dev->snap_exists = true;
- rbd_dev->read_only = true; /* No choice for snapshots */
+ rbd_dev->mapping.snap_id = snap_id;
+ rbd_dev->mapping.snap_exists = true;
+ rbd_dev->mapping.read_only = true;
}
ret = 0;
@@ -1532,7 +1537,7 @@ static void rbd_rq_fn(struct request_queue *q)
size = blk_rq_bytes(rq);
ofs = blk_rq_pos(rq) * SECTOR_SIZE;
rq_bio = rq->bio;
- if (do_write && rbd_dev->read_only) {
+ if (do_write && rbd_dev->mapping.read_only) {
__blk_end_request_all(rq, -EROFS);
continue;
}
@@ -1541,7 +1546,8 @@ static void rbd_rq_fn(struct request_queue *q)
down_read(&rbd_dev->header_rwsem);
- if (rbd_dev->snap_id != CEPH_NOSNAP && !rbd_dev->snap_exists) {
+ if (rbd_dev->mapping.snap_id != CEPH_NOSNAP &&
+ !rbd_dev->mapping.snap_exists) {
up_read(&rbd_dev->header_rwsem);
dout("request for non-existent snapshot");
spin_lock_irq(q->queue_lock);
@@ -1595,7 +1601,7 @@ static void rbd_rq_fn(struct request_queue *q)
coll, cur_seg);
else
rbd_req_read(rq, rbd_dev,
- rbd_dev->snap_id,
+ rbd_dev->mapping.snap_id,
ofs,
op_size, bio,
coll, cur_seg);
@@ -1767,7 +1773,7 @@ static int rbd_header_add_snap(struct rbd_device
*rbd_dev,
struct ceph_mon_client *monc;
/* we should create a snapshot only if we're pointing at the head */
- if (rbd_dev->snap_id != CEPH_NOSNAP)
+ if (rbd_dev->mapping.snap_id != CEPH_NOSNAP)
return -EINVAL;
monc = &rbd_dev->rbd_client->client->monc;
@@ -1821,7 +1827,7 @@ static int __rbd_refresh_header(struct rbd_device
*rbd_dev, u64 *hver)
down_write(&rbd_dev->header_rwsem);
/* resized? */
- if (rbd_dev->snap_id == CEPH_NOSNAP) {
+ if (rbd_dev->mapping.snap_id == CEPH_NOSNAP) {
sector_t size = (sector_t) h.image_size / SECTOR_SIZE;
dout("setting size to %llu sectors", (unsigned long long) size);
@@ -2004,7 +2010,7 @@ static ssize_t rbd_snap_show(struct device *dev,
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
- return sprintf(buf, "%s\n", rbd_dev->snap_name);
+ return sprintf(buf, "%s\n", rbd_dev->mapping.snap_name);
}
static ssize_t rbd_image_refresh(struct device *dev,
@@ -2205,11 +2211,12 @@ static int rbd_dev_snap_devs_update(struct
rbd_device *rbd_dev)
/* Existing snapshot not in the new snap context */
- if (rbd_dev->snap_id == snap->id)
- rbd_dev->snap_exists = false;
+ if (rbd_dev->mapping.snap_id == snap->id)
+ rbd_dev->mapping.snap_exists = false;
__rbd_remove_snap_dev(snap);
dout("%ssnap id %llu has been removed\n",
- rbd_dev->snap_id == snap->id ? "mapped " : "",
+ rbd_dev->mapping.snap_id == snap->id ?
+ "mapped " : "",
(unsigned long long) snap->id);
/* Done with this list entry; advance */
@@ -2522,18 +2529,18 @@ static int rbd_add_parse_args(struct rbd_device
*rbd_dev,
* The snapshot name is optional. If none is is supplied,
* we use the default value.
*/
- rbd_dev->snap_name = dup_token(&buf, &len);
- if (!rbd_dev->snap_name)
+ rbd_dev->mapping.snap_name = dup_token(&buf, &len);
+ if (!rbd_dev->mapping.snap_name)
goto out_err;
if (!len) {
/* Replace the empty name with the default */
- kfree(rbd_dev->snap_name);
- rbd_dev->snap_name
+ kfree(rbd_dev->mapping.snap_name);
+ rbd_dev->mapping.snap_name
= kmalloc(sizeof (RBD_SNAP_HEAD_NAME), GFP_KERNEL);
- if (!rbd_dev->snap_name)
+ if (!rbd_dev->mapping.snap_name)
goto out_err;
- memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
+ memcpy(rbd_dev->mapping.snap_name, RBD_SNAP_HEAD_NAME,
sizeof (RBD_SNAP_HEAD_NAME));
}
@@ -2642,7 +2649,7 @@ err_out_client:
rbd_put_client(rbd_dev);
err_put_id:
if (rbd_dev->pool_name) {
- kfree(rbd_dev->snap_name);
+ kfree(rbd_dev->mapping.snap_name);
kfree(rbd_dev->header_name);
kfree(rbd_dev->image_name);
kfree(rbd_dev->pool_name);
@@ -2695,7 +2702,7 @@ static void rbd_dev_release(struct device *dev)
unregister_blkdev(rbd_dev->major, rbd_dev->name);
/* done with the id, and with the rbd_dev */
- kfree(rbd_dev->snap_name);
+ kfree(rbd_dev->mapping.snap_name);
kfree(rbd_dev->header_name);
kfree(rbd_dev->pool_name);
kfree(rbd_dev->image_name);
--
1.7.9.5
--
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