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rbd: show the entire chain of parent images

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Make /sys/bus/rbd/devices/<id>/parent show the entire chain of parent
images.  While at it, kernel sprintf() doesn't return negative values,
casting to unsigned long long is no longer necessary and there is no
good reason to split into multiple sprintf() calls.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Alex Elder <elder@linaro.org>
This commit is contained in:
Ilya Dryomov
2014-07-22 21:53:07 +04:00
parent 08a0f24e4c
commit ff96128fb0
2 changed files with 23 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/ABI/testing/sysfs-bus-rbd
View File

@@ -94,5 +94,5 @@ current_snap
parent parent
Information identifying the pool, image, and snapshot id for Information identifying the chain of parent images in a layered rbd
the parent image in a layered rbd image (format 2 only). image. Entries are separated by empty lines.

52
drivers/block/rbd.c
View File

@@ -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 a v2 image, shows the chain of parent images, separated by empty
* for the parent image. If there is no parent, simply shows * lines. For v1 images or if there is no parent, shows "(no parent
* "(no parent image)". * image)".
*/ */
static ssize_t rbd_parent_show(struct device *dev, static ssize_t rbd_parent_show(struct device *dev,
struct device_attribute *attr, struct device_attribute *attr,
char *buf) char *buf)
{ {
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev); struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
struct rbd_spec *spec = rbd_dev->parent_spec; ssize_t count = 0;
int count;
char *bufp = buf;
if (!spec) if (!rbd_dev->parent)
return sprintf(buf, "(no parent image)\n"); return sprintf(buf, "(no parent image)\n");
count = sprintf(bufp, "pool_id %llu\npool_name %s\n", for ( ; rbd_dev->parent; rbd_dev = rbd_dev->parent) {
(unsigned long long) spec->pool_id, spec->pool_name); struct rbd_spec *spec = rbd_dev->parent_spec;
if (count < 0)
return count;
bufp += count;
count = sprintf(bufp, "image_id %s\nimage_name %s\n", spec->image_id, count += sprintf(&buf[count], "%s"
spec->image_name ? spec->image_name : "(unknown)"); "pool_id %llu\npool_name %s\n"
if (count < 0) "image_id %s\nimage_name %s\n"
return count; "snap_id %llu\nsnap_name %s\n"
bufp += count; "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);
}
count = sprintf(bufp, "snap_id %llu\nsnap_name %s\n", return count;
(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);
} }
static ssize_t rbd_image_refresh(struct device *dev, static ssize_t rbd_image_refresh(struct device *dev,