On Wed, 11 Jul 2012, Josh Durgin wrote:
> On 07/11/2012 07:02 AM, Alex Elder wrote:
> > An rbd device's pool name is used to specify the pool to use for an
> > rbd image when it gets mapped (via rbd_add()). However, only the
> > pool id can be relied on to be invariant--the name of a pool can
> > change at any time.
> >
> > This means that the name of the pool is potentially stale as soon as
> > the image is mapped, so it's a bad idea to record this information.
> > So only store the pool id, not its name, in an rbd_dev.
> >
> > Here are a few specific notes about this change:
> > - The "pool" name device attribute (/sys/bus/rbd/devices/<N>/pool)
> > goes away. In its place is a "pool_id" attribute that provide
> > the numeric pool id for the rbd image.
>
> We're using the pool name for udev to provide a predictable device name
> (/dev/rbd/poolname/imagename[@snapname]), so we probably want to keep
> the sysfs attribute. I don't think there's a good way for us to detect
> pool renames right now though, so we should document that the pool
> name reported does not reflect any potential renames.
Whoops. Let's just make sure that we don't use it for anything other than
sysfs.
>
> > - rbd_add_parse_args() now returns a pointer to a dynamically-
> > allocated copy of the pool name taken from the arguments.
> > - rbd_add() has been changed to handle freeing the pool name,
> > both in error cases and in the normal case after the pool id
> > has been recorded.
> >
> > Signed-off-by: Alex Elder<elder@xxxxxxxxxxx>
> > ---
> > drivers/block/rbd.c | 74
> > +++++++++++++++++++++++++++++++-------------------
> > 1 files changed, 46 insertions(+), 28 deletions(-)
> >
> > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> > index 3aa0ca0..76e978c 100644
> > --- a/drivers/block/rbd.c
> > +++ b/drivers/block/rbd.c
> > @@ -56,7 +56,6 @@
> > #define RBD_MINORS_PER_MAJOR 256 /* max minors per
> > blkdev */
> >
> > #define RBD_MAX_MD_NAME_LEN (RBD_MAX_OBJ_NAME_LEN + sizeof(RBD_SUFFIX))
> > -#define RBD_MAX_POOL_NAME_LEN 64
> > #define RBD_MAX_SNAP_NAME_LEN 32
> > #define RBD_MAX_OPT_LEN 1024
> >
> > @@ -166,8 +165,7 @@ struct rbd_device {
> > char obj[RBD_MAX_OBJ_NAME_LEN]; /* rbd image name
> > */
> > int obj_len;
> > char obj_md_name[RBD_MAX_MD_NAME_LEN]; /* hdr nm.
> > */
> > - char pool_name[RBD_MAX_POOL_NAME_LEN];
> > - int poolid;
> > + int pool_id;
> >
> > struct ceph_osd_event *watch_event;
> > struct ceph_osd_request *watch_request;
> > @@ -930,7 +928,7 @@ static int rbd_do_request(struct request *rq,
> > layout->fl_stripe_unit = cpu_to_le32(1<< RBD_MAX_OBJ_ORDER);
> > layout->fl_stripe_count = cpu_to_le32(1);
> > layout->fl_object_size = cpu_to_le32(1<< RBD_MAX_OBJ_ORDER);
> > - layout->fl_pg_pool = cpu_to_le32(dev->poolid);
> > + layout->fl_pg_pool = cpu_to_le32(dev->pool_id);
> > ceph_calc_raw_layout(osdc, layout, snapid, ofs,&len,&bno,
> > req, ops);
> >
> > @@ -1653,7 +1651,7 @@ static int rbd_header_add_snap(struct rbd_device *dev,
> > return -EINVAL;
> >
> > monc =&dev->rbd_client->client->monc;
> > - ret = ceph_monc_create_snapid(monc, dev->poolid,&new_snapid);
> > + ret = ceph_monc_create_snapid(monc, dev->pool_id,&new_snapid);
> > dout("created snapid=%lld\n", new_snapid);
> > if (ret< 0)
> > return ret;
> > @@ -1851,12 +1849,12 @@ static ssize_t rbd_client_id_show(struct device
> > *dev,
> > ceph_client_id(rbd_dev->rbd_client->client));
> > }
> >
> > -static ssize_t rbd_pool_show(struct device *dev,
> > +static ssize_t rbd_pool_id_show(struct device *dev,
> > struct device_attribute *attr, char *buf)
> > {
> > struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
> >
> > - return sprintf(buf, "%s\n", rbd_dev->pool_name);
> > + return sprintf(buf, "%d\n", rbd_dev->pool_id);
> > }
> >
> > static ssize_t rbd_name_show(struct device *dev,
> > @@ -1898,7 +1896,7 @@ static ssize_t rbd_image_refresh(struct device *dev,
> > static DEVICE_ATTR(size, S_IRUGO, rbd_size_show, NULL);
> > static DEVICE_ATTR(major, S_IRUGO, rbd_major_show, NULL);
> > static DEVICE_ATTR(client_id, S_IRUGO, rbd_client_id_show, NULL);
> > -static DEVICE_ATTR(pool, S_IRUGO, rbd_pool_show, NULL);
> > +static DEVICE_ATTR(pool_id, S_IRUGO, rbd_pool_id_show, NULL);
> > static DEVICE_ATTR(name, S_IRUGO, rbd_name_show, NULL);
> > static DEVICE_ATTR(refresh, S_IWUSR, NULL, rbd_image_refresh);
> > static DEVICE_ATTR(current_snap, S_IRUGO, rbd_snap_show, NULL);
> > @@ -1908,7 +1906,7 @@ static struct attribute *rbd_attrs[] = {
> > &dev_attr_size.attr,
> > &dev_attr_major.attr,
> > &dev_attr_client_id.attr,
> > - &dev_attr_pool.attr,
> > + &dev_attr_pool_id.attr,
> > &dev_attr_name.attr,
> > &dev_attr_current_snap.attr,
> > &dev_attr_refresh.attr,
> > @@ -2329,25 +2327,31 @@ static inline char *dup_token(const char **buf,
> > size_t *lenp)
> > }
> >
> > /*
> > - * This fills in the pool_name, obj, obj_len, snap_name, obj_len,
> > - * rbd_dev, rbd_md_name, and name fields of the given rbd_dev, based
> > - * on the list of monitor addresses and other options provided via
> > - * /sys/bus/rbd/add.
> > + * This fills in the obj, obj_len, snap_name, rbd_dev, rbd_md_name,
> > + * and name fields of the given rbd_dev, based on the list of
> > + * monitor addresses and other options provided via /sys/bus/rbd/add.
> > + *
> > + * Returns a pointer to a dynamically-allocated buffer containing
> > + * the pool name provided, or a pointer-coded errno if an error
> > + * occurs.
> > */
> > -static int rbd_add_parse_args(struct rbd_device *rbd_dev,
> > +static char *rbd_add_parse_args(struct rbd_device *rbd_dev,
> > const char *buf,
> > const char **mon_addrs,
> > size_t *mon_addrs_size,
> > char *options,
> > size_t options_size)
> > {
> > - size_t len;
> > + size_t len;
> > + int ret = -EINVAL;
> > + char *pool_name = NULL;
> >
> > /* The first four tokens are required */
> >
> > len = next_token(&buf);
> > if (!len)
> > - return -EINVAL;
> > + goto out_err;
> > +
> > *mon_addrs_size = len + 1;
> > *mon_addrs = buf;
> >
> > @@ -2355,15 +2359,17 @@ static int rbd_add_parse_args(struct rbd_device
> > *rbd_dev,
> >
> > len = copy_token(&buf, options, options_size);
> > if (!len || len>= options_size)
> > - return -EINVAL;
> > + goto out_err;
> >
> > - len = copy_token(&buf, rbd_dev->pool_name, sizeof
> > (rbd_dev->pool_name));
> > - if (!len || len>= sizeof (rbd_dev->pool_name))
> > - return -EINVAL;
> > + pool_name = dup_token(&buf, NULL);
> > + if (!pool_name) {
> > + ret = -ENOMEM;
> > + goto out_err;
> > + }
> >
> > len = copy_token(&buf, rbd_dev->obj, sizeof (rbd_dev->obj));
> > if (!len || len>= sizeof (rbd_dev->obj))
> > - return -EINVAL;
> > + goto out_err;
> >
> > /* We have the object length in hand, save it. */
> >
> > @@ -2382,9 +2388,14 @@ static int rbd_add_parse_args(struct rbd_device
> > *rbd_dev,
> > memcpy(rbd_dev->snap_name, RBD_SNAP_HEAD_NAME,
> > sizeof (RBD_SNAP_HEAD_NAME));
> > else if (len>= sizeof (rbd_dev->snap_name))
> > - return -EINVAL;
> > + goto out_err;
> >
> > - return 0;
> > + return pool_name;
> > +
> > +out_err:
> > + kfree(pool_name);
> > +
> > + return ERR_PTR(ret);
> > }
> >
> > static ssize_t rbd_add(struct bus_type *bus,
> > @@ -2396,6 +2407,7 @@ static ssize_t rbd_add(struct bus_type *bus,
> > size_t mon_addrs_size = 0;
> > char *options = NULL;
> > struct ceph_osd_client *osdc;
> > + char *pool_name;
> > int rc = -ENOMEM;
> >
> > if (!try_module_get(THIS_MODULE))
> > @@ -2425,10 +2437,14 @@ static ssize_t rbd_add(struct bus_type *bus,
> > sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->id);
> >
> > /* parse add command */
> > - rc = rbd_add_parse_args(rbd_dev, buf,&mon_addrs,&mon_addrs_size,
> > - options, count);
> > - if (rc)
> > + pool_name = rbd_add_parse_args(rbd_dev, buf,
> > + &mon_addrs,&mon_addrs_size,
> > + options, count);
> > + if (IS_ERR(pool_name)) {
> > + rc = PTR_ERR(pool_name);
> > + pool_name = NULL;
> > goto err_put_id;
> > + }
> >
> > rbd_dev->rbd_client = rbd_get_client(mon_addrs, mon_addrs_size - 1,
> > options);
> > @@ -2439,10 +2455,10 @@ static ssize_t rbd_add(struct bus_type *bus,
> >
> > /* pick the pool */
> > osdc =&rbd_dev->rbd_client->client->osdc;
> > - rc = ceph_pg_poolid_by_name(osdc->osdmap, rbd_dev->pool_name);
> > + rc = ceph_pg_poolid_by_name(osdc->osdmap, pool_name);
> > if (rc< 0)
> > goto err_out_client;
> > - rbd_dev->poolid = rc;
> > + rbd_dev->pool_id = rc;
> >
> > /* register our block device */
> > rc = register_blkdev(0, rbd_dev->name);
> > @@ -2453,6 +2469,7 @@ static ssize_t rbd_add(struct bus_type *bus,
> > rc = rbd_bus_add_dev(rbd_dev);
> > if (rc)
> > goto err_out_blkdev;
> > + kfree(pool_name);
> >
> > /*
> > * At this point cleanup in the event of an error is the job
> > @@ -2482,6 +2499,7 @@ err_out_blkdev:
> > err_out_client:
> > rbd_put_client(rbd_dev);
> > err_put_id:
> > + kfree(pool_name);
> > rbd_id_put(rbd_dev);
> > err_nomem:
> > kfree(options);
>
> --
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