On Wed, 2018-11-28 at 00:13 -0600, Benjamin Marzinski wrote: > dm_is_mpath() would return 0 if either a device was not a multipath > device or if the libdevmapper command failed. Because dm_is_mpath() > didn't distinguish between these situations, dm_get_events() could > assume that a device was not really a multipath device, when in fact > it > was, and the libdevmapper command simply failed. This would cause the > dmevents polling waiter to stop monitoring the device. > > In reality, the call to dm_is_mpath() isn't necessary, because > dm_get_events() will already verify that the device name is on the > list > of devices to wait for. However, if there are a large number of > non-multipath devices on the system, ignoring them can be > useful. Thus, > if dm_is_mpath() successfully runs the libdevmapper command and > verifies > that the device is not a multipath device, dm_get_events() should > skip > it. But if the libdevmapper command fails, dm_get_events() should > still > check the device list, to see if the device should be monitored. > > This commit makes dm_is_mpath() return -1 for situations where > the libdevmapper command failed, and makes dm_get_events() only > ignore > the device on a return of 0. > > Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx> > --- Two minor remarks: 1. You've changed dm_is_mpath() calls from "if (!result)" to "if (result == 0)" or "if (result != 1)" syntax, but you missed the call in watch_dmevents(). I suggest that, for clarity, you change that one as well. 2. We should add a condlog(2,...) to dm_is_mpath() if it returns -1. Otherwise, ACK. Martin -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
