@@ -435,6 +435,11 @@ static int rbd_dev_refresh(struct rbd_device *rbd_dev);
static int rbd_dev_v2_refresh(struct rbd_device *rbd_dev);
static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
u64 snap_id);
+static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
+ u8 *order, u64 *snap_size);
+static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64
snap_id,
+ u64 *snap_features);
+static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char
*name);
This patch defines a handful of new functions that will allow us to get rid of the rbd device structure's list of snapshots. Define rbd_snap_id_by_name() to look up a snapshot id given its name. This is efficient for format 1 images but not for format 2. Fortunately it only gets called at mapping time so it's not that critical. Use rbd_snap_id_by_name() to find out the id for a snapshot getting mapped, and pass that id to new functions rbd_snap_size() and rbd_snap_features() to look up information about a given snapshot's size and feature mask given its snapshot id. All this gets done in rbd_dev_mapping_set(). As a result, snap_by_name() is no longer needed, so get rid of it. Signed-off-by: Alex Elder <elder@inktank.com> --- drivers/block/rbd.c | 152 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 129 insertions(+), 23 deletions(-) static int rbd_open(struct block_device *bdev, fmode_t mode) { @@ -840,7 +845,8 @@ static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id) return BAD_SNAP_INDEX; } -static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u64 snap_id) +static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, + u64 snap_id) { u32 which; @@ -863,35 +869,85 @@ static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id) return rbd_dev_v2_snap_name(rbd_dev, snap_id); } -static struct rbd_snap *snap_by_name(struct rbd_device *rbd_dev, - const char *snap_name) +static int rbd_snap_size(struct rbd_device *rbd_dev, u64 snap_id, + u64 *snap_size) { - struct rbd_snap *snap; + rbd_assert(rbd_image_format_valid(rbd_dev->image_format)); + if (snap_id == CEPH_NOSNAP) { + *snap_size = rbd_dev->header.image_size; + } else if (rbd_dev->image_format == 1) { + u32 which; - list_for_each_entry(snap, &rbd_dev->snaps, node) - if (!strcmp(snap_name, snap->name)) - return snap; + which = rbd_dev_snap_index(rbd_dev, snap_id); + if (which == BAD_SNAP_INDEX) + return -ENOENT; - return NULL; + *snap_size = rbd_dev->header.snap_sizes[which]; + } else { + u64 size = 0; + int ret; + + ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, &size); + if (ret) + return ret; + + *snap_size = size; + } + return 0; } -static int rbd_dev_mapping_set(struct rbd_device *rbd_dev) +static int rbd_snap_features(struct rbd_device *rbd_dev, u64 snap_id, + u64 *snap_features) { - if (!memcmp(rbd_dev->spec->snap_name, RBD_SNAP_HEAD_NAME, - sizeof (RBD_SNAP_HEAD_NAME))) { - rbd_dev->mapping.size = rbd_dev->header.image_size; - rbd_dev->mapping.features = rbd_dev->header.features; + rbd_assert(rbd_image_format_valid(rbd_dev->image_format)); + if (snap_id == CEPH_NOSNAP) { + *snap_features = rbd_dev->header.features; + } else if (rbd_dev->image_format == 1) { + *snap_features = 0; /* No features for format 1 */ } else { - struct rbd_snap *snap; + u64 features = 0; + int ret; + + ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, &features); + if (ret) + return ret; + + *snap_features = features; + } + return 0; +} - snap = snap_by_name(rbd_dev, rbd_dev->spec->snap_name); - if (!snap) +static int rbd_dev_mapping_set(struct rbd_device *rbd_dev) +{ + const char *snap_name = rbd_dev->spec->snap_name; + u64 snap_id; + u64 size = 0; + u64 features = 0; + int ret; + + if (strcmp(snap_name, RBD_SNAP_HEAD_NAME)) { + snap_id = rbd_snap_id_by_name(rbd_dev, snap_name); + if (snap_id == CEPH_NOSNAP) return -ENOENT; - rbd_dev->mapping.size = snap->size; - rbd_dev->mapping.features = snap->features; - rbd_dev->mapping.read_only = true; + } else { + snap_id = CEPH_NOSNAP; } + ret = rbd_snap_size(rbd_dev, snap_id, &size); + if (ret) + return ret; + ret = rbd_snap_features(rbd_dev, snap_id, &features); + if (ret) + return ret; + + rbd_dev->mapping.size = size; + rbd_dev->mapping.features = features; + + /* If we are mapping a snapshot it must be marked read-only */ + + if (snap_id != CEPH_NOSNAP) + rbd_dev->mapping.read_only = true; + return 0; } @@ -3766,6 +3822,56 @@ out: return image_name; } +static u64 rbd_v1_snap_id_by_name(struct rbd_device *rbd_dev, const char *name) +{ + struct ceph_snap_context *snapc = rbd_dev->header.snapc; + const char *snap_name; + u32 which = 0; + + /* Skip over names until we find the one we are looking for */ + + snap_name = rbd_dev->header.snap_names; + while (which < snapc->num_snaps) { + if (!strcmp(name, snap_name)) + return snapc->snaps[which]; + snap_name += strlen(snap_name) + 1; + which++; + } + return CEPH_NOSNAP; +} + +static u64 rbd_v2_snap_id_by_name(struct rbd_device *rbd_dev, const char *name) +{ + struct ceph_snap_context *snapc = rbd_dev->header.snapc; + u32 which; + bool found = false; + u64 snap_id; + + for (which = 0; !found && which < snapc->num_snaps; which++) { + const char *snap_name; + + snap_id = snapc->snaps[which]; + snap_name = rbd_dev_v2_snap_name(rbd_dev, snap_id); + if (IS_ERR(snap_name)) + break; + found = !strcmp(name, snap_name); + kfree(snap_name); + } + return found ? snap_id : CEPH_NOSNAP; +} + +/* + * Assumes name is never RBD_SNAP_HEAD_NAME; returns CEPH_NOSNAP if + * no snapshot by that name is found, or if an error occurs. + */ +static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char *name) +{ + if (rbd_dev->image_format == 1) + return rbd_v1_snap_id_by_name(rbd_dev, name); + + return rbd_v2_snap_id_by_name(rbd_dev, name); +} + /* * When an rbd image has a parent image, it is identified by the * pool, image, and snapshot ids (not names). This function fills @@ -3797,12 +3903,12 @@ static int rbd_dev_spec_update(struct rbd_device *rbd_dev) */ if (spec->pool_name) { if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) { - struct rbd_snap *snap; + u64 snap_id; - snap = snap_by_name(rbd_dev, spec->snap_name); - if (!snap) + snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name); + if (snap_id == CEPH_NOSNAP) return -ENOENT; - spec->snap_id = snap->id; + spec->snap_id = snap_id; } else { spec->snap_id = CEPH_NOSNAP; }