Red Hat Bugzilla – Bug 862095
liblvm2app: property "data_percent" returns -1 for thin volumes
Last modified: 2013-02-21 03:14:08 EST
Description of problem:
When using the following line of code:
value = lvm_lv_get_property(lvmLV, "data_percent");
The value is the the same percentage reported by the "lvs" command for thin pools but returns invalid (-1) for thin volumes.
LV VG Attr LSize Pool Data% Move Log Copy% Convert
Pool_One MyGroup twi-a-tz- 1.00g 9.96
thin_vol2 MyGroup Vwi-a-tz- 2.00g Pool_One 4.98
for Pool_One --> value = 9960937
for thin_vol2 --> value = -1
Version-Release number of selected component (if applicable):
LVM version: 2.02.98(2)-git (2012-08-24)
Library version: 1.02.77-git (2012-08-24)
Driver version: 4.22.0
As reported in bug #838257 the number is reported with a uint64_t
but the percentage is an int32_t so sizes and signs are getting
Created attachment 621019 [details]
Patch to correctly return value of property "data_percent"
And what about the values when it's a snapshot, and various other conditions in the 'lvs' code.
Do we always want the output to match? If so, we should find a better way to share the logic to arrive at the right number before going into the mechanics of outputting it either via liblvm or a cmdline report like lvs.
How many other fields similarly don't match?
Fixed upstream with slightly different patch to provide matching behavior with lvs reporting functionality (data_percent reports also snap_percent for old-snaps):
Here is simple lvm2api test program which should pass now:
# Create pool & thin & snap LVs
lvcreate -L5M -T vg/pool
lvcreate -V1M -T vg/pool -n thin
int main(int argc, char *argv)
struct lvm_property_value v;
handle = lvm_init(NULL);
vg = lvm_vg_open(handle, argv, "r", 0);
lv = lvm_lv_from_name(vg, "thin");
v = lvm_lv_get_property(lv, "data_percent");
return (v.is_valid && v.value.integer != -1) ? 0 : 1;
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.