From f84344f334df8f1d41eba7cfa7eb1024da25e1fe Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Fri, 31 Aug 2012 17:29:51 -0500 Subject: [PATCH] rbd: separate mapping info in rbd_dev 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 Reviewed-by: Josh Durgin --- 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 eb6b7723906b..dff621060432 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); -- 2.30.2