From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Durgin Subject: Re: [PATCH 1/7] rbd: separate mapping info in rbd_dev Date: Fri, 07 Sep 2012 11:58:38 -0700 Message-ID: <504A43DE.4010207@inktank.com> References: <5049F951.2030706@inktank.com> <5049FA67.3060904@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f46.google.com ([209.85.160.46]:55660 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751737Ab2IGS6l (ORCPT ); Fri, 7 Sep 2012 14:58:41 -0400 Received: by pbbrr13 with SMTP id rr13so32862pbb.19 for ; Fri, 07 Sep 2012 11:58:41 -0700 (PDT) In-Reply-To: <5049FA67.3060904@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Alex Elder Cc: ceph-devel@vger.kernel.org Might want to keep the comments about the fields moved to the mapping struct, but it looks good to me. Reviewed-by: Josh Durgin On 09/07/2012 06:45 AM, Alex Elder wrote: > 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 > --- > 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); >