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-rw-r--r--Documentation/ABI/testing/sysfs-bus-rbd4
-rw-r--r--drivers/block/rbd.c56
2 files changed, 25 insertions, 35 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-rbd b/Documentation/ABI/testing/sysfs-bus-rbd
index 501adc2a9ec7..2ddd680929d8 100644
--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -94,5 +94,5 @@ current_snap
parent
- Information identifying the pool, image, and snapshot id for
- the parent image in a layered rbd image (format 2 only).
+ Information identifying the chain of parent images in a layered rbd
+ image. Entries are separated by empty lines.
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 703b728e05fa..7847fbb949ff 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3685,46 +3685,36 @@ static ssize_t rbd_snap_show(struct device *dev,
}
/*
- * For an rbd v2 image, shows the pool id, image id, and snapshot id
- * for the parent image. If there is no parent, simply shows
- * "(no parent image)".
+ * For a v2 image, shows the chain of parent images, separated by empty
+ * lines. For v1 images or if there is no parent, shows "(no parent
+ * image)".
*/
static ssize_t rbd_parent_show(struct device *dev,
- struct device_attribute *attr,
- char *buf)
+ struct device_attribute *attr,
+ char *buf)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
- struct rbd_spec *spec = rbd_dev->parent_spec;
- int count;
- char *bufp = buf;
+ ssize_t count = 0;
- if (!spec)
+ if (!rbd_dev->parent)
return sprintf(buf, "(no parent image)\n");
- count = sprintf(bufp, "pool_id %llu\npool_name %s\n",
- (unsigned long long) spec->pool_id, spec->pool_name);
- if (count < 0)
- return count;
- bufp += count;
-
- count = sprintf(bufp, "image_id %s\nimage_name %s\n", spec->image_id,
- spec->image_name ? spec->image_name : "(unknown)");
- if (count < 0)
- return count;
- bufp += count;
-
- count = sprintf(bufp, "snap_id %llu\nsnap_name %s\n",
- (unsigned long long) spec->snap_id, spec->snap_name);
- if (count < 0)
- return count;
- bufp += count;
-
- count = sprintf(bufp, "overlap %llu\n", rbd_dev->parent_overlap);
- if (count < 0)
- return count;
- bufp += count;
-
- return (ssize_t) (bufp - buf);
+ for ( ; rbd_dev->parent; rbd_dev = rbd_dev->parent) {
+ struct rbd_spec *spec = rbd_dev->parent_spec;
+
+ count += sprintf(&buf[count], "%s"
+ "pool_id %llu\npool_name %s\n"
+ "image_id %s\nimage_name %s\n"
+ "snap_id %llu\nsnap_name %s\n"
+ "overlap %llu\n",
+ !count ? "" : "\n", /* first? */
+ spec->pool_id, spec->pool_name,
+ spec->image_id, spec->image_name ?: "(unknown)",
+ spec->snap_id, spec->snap_name,
+ rbd_dev->parent_overlap);
+ }
+
+ return count;
}
static ssize_t rbd_image_refresh(struct device *dev,
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