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merged 1 commit into from
Apr 14, 2025
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Check that there are no changes during SR.scan #6413

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37 changes: 23 additions & 14 deletions ocaml/xapi/xapi_sr.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -757,6 +757,11 @@ let update_vdis ~__context ~sr db_vdis vdi_infos =

(* Perform a scan of this locally-attached SR *)
let scan ~__context ~sr =
let module RefSet = Set.Make (struct
type t = [`VDI] Ref.t

let compare = Ref.compare
end) in
let open Storage_access in
let task = Context.get_task_id __context in
let module C = Storage_interface.StorageAPI (Idl.Exn.GenClient (struct
Expand All @@ -781,9 +786,21 @@ let scan ~__context ~sr =
(* It is sufficient to just compare the refs in two db_vdis, as this
is what update_vdis uses to determine what to delete *)
let vdis_ref_equal db_vdi1 db_vdi2 =
Listext.List.set_difference (List.map fst db_vdi1)
(List.map fst db_vdi2)
= []
let refs1 = RefSet.of_list (List.map fst db_vdi1) in
let refs2 = RefSet.of_list (List.map fst db_vdi2) in
if RefSet.equal refs1 refs2 then
true
else
let log_diff label a b =
RefSet.diff a b
|> RefSet.elements
|> List.map Ref.string_of
|> String.concat " "
|> debug "%s: VDIs %s during scan: %s" __FUNCTION__ label
in
log_diff "removed" refs1 refs2 ;
log_diff "added" refs2 refs1 ;
false
in
let db_vdis_before = find_vdis () in
let vs, sr_info =
Expand All @@ -793,21 +810,13 @@ let scan ~__context ~sr =
let db_vdis_after = find_vdis () in
if limit > 0 && not (vdis_ref_equal db_vdis_before db_vdis_after)
then (
debug
"%s detected db change while scanning, before scan vdis %s, \
after scan vdis %s, retry limit left %d"
__FUNCTION__
(List.map (fun (_, v) -> v.vDI_uuid) db_vdis_before
|> String.concat ","
)
(List.map (fun (_, v) -> v.vDI_uuid) db_vdis_after
|> String.concat ","
)
limit ;
debug "%s detected db change while scanning, retry limit left %d"
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As we report the VDIs that have been added or removed in vdis_ref_equal I think it is ok to remove the dump of the two lists (before and after).

__FUNCTION__ limit ;
(scan_rec [@tailcall]) (limit - 1)
) else if limit = 0 then
Helpers.internal_error "SR.scan retry limit exceeded"
else (
debug "%s no change detected, updating VDIs" __FUNCTION__ ;
update_vdis ~__context ~sr db_vdis_after vs ;
let virtual_allocation =
List.fold_left
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