Set the key for mapping objects to pgs within an io context.
The key is used instead of the object name to determine which
placement groups an object is put in. This affects all subsequent
operations of the io context - until a different locator key is
set, all objects in this io context will be placed in the same pg.
This is useful if you need to do clone_range operations, which must
be done with the source and destination objects in the same pg.
@param io the io context to change
@param key the key to use as the object locator, or NULL to discard
any previously set key
Set the key for mapping objects to pgs within an io context.
The key is used instead of the object name to determine which placement groups an object is put in. This affects all subsequent operations of the io context - until a different locator key is set, all objects in this io context will be placed in the same pg.
This is useful if you need to do clone_range operations, which must be done with the source and destination objects in the same pg.
@param io the io context to change @param key the key to use as the object locator, or NULL to discard any previously set key