[Libguestfs] [PATCH] sparsify: Let --in-place capture ^C and shut down gracefully (RHBZ#1277122).
Richard W.M. Jones
rjones at redhat.com
Wed Nov 4 12:33:15 UTC 2015
When virt-sparsify receives a user quit signal (eg from ^C) it
currently kills virt-sparsify and qemu instantly, meaning any mount +
fstrim in progress is uncleanly stopped. The (minor) side effect of
this is that the guest filesystem may require a journal replay or fsck
on boot.
Let virt-sparsify capture the user quit signal and shut down
gracefully.
It is not thought that the previous behaviour could cause guest
corruption; see
https://lists.nongnu.org/archive/html/qemu-devel/2015-11/threads.html#00402
for discussion.
---
sparsify/in_place.ml | 143 ++++++++++++++++++++++++++++++---------------------
1 file changed, 84 insertions(+), 59 deletions(-)
diff --git a/sparsify/in_place.ml b/sparsify/in_place.ml
index 36100de..3a2b32c 100644
--- a/sparsify/in_place.ml
+++ b/sparsify/in_place.ml
@@ -35,8 +35,15 @@ let rec run disk format ignores machine_readable zeroes =
if trace () then g#set_trace true;
if verbose () then g#set_verbose true;
+ (* Capture ^C and clean up gracefully. *)
+ let quit = ref false in
+ let set_quit _ = quit := true in
+ Sys.set_signal Sys.sigint (Sys.Signal_handle set_quit);
+ Sys.set_signal Sys.sigquit (Sys.Signal_handle set_quit);
+ g#set_pgroup true;
+
try
- perform g disk format ignores machine_readable zeroes
+ perform g disk format ignores machine_readable zeroes quit
with
G.Error msg as exn ->
if g#last_errno () = G.Errno.errno_ENOTSUP then (
@@ -45,7 +52,7 @@ let rec run disk format ignores machine_readable zeroes =
)
else raise exn
-and perform g disk format ignores machine_readable zeroes =
+and perform g disk format ignores machine_readable zeroes quit =
(* XXX Current limitation of the API. Can remove this hunk in future. *)
let format =
match format with
@@ -71,80 +78,98 @@ and perform g disk format ignores machine_readable zeroes =
let is_read_only_lv = is_read_only_lv g in
- List.iter (
- fun fs ->
- if not (is_ignored fs) && not (is_read_only_lv fs) then (
- if List.mem fs zeroes then (
- message (f_"Zeroing %s") fs;
+ let tasks =
+ List.map (
+ fun fs () ->
+ if not (is_ignored fs) && not (is_read_only_lv fs) then (
+ if List.mem fs zeroes then (
+ message (f_"Zeroing %s") fs;
- if not (g#blkdiscardzeroes fs) then
- g#zero_device fs;
- g#blkdiscard fs
- ) else (
- let mounted =
- try g#mount_options "discard" fs "/"; true
- with _ -> false in
-
- if mounted then (
- message (f_"Trimming %s") fs;
-
- g#fstrim "/"
+ if not (g#blkdiscardzeroes fs) then
+ g#zero_device fs;
+ g#blkdiscard fs
) else (
- let is_linux_x86_swap =
- (* Look for the signature for Linux swap on i386.
- * Location depends on page size, so it definitely won't
- * work on non-x86 architectures (eg. on PPC, page size is
- * 64K). Also this avoids hibernated swap space: in those,
- * the signature is moved to a different location.
- *)
- try g#pread_device fs 10 4086L = "SWAPSPACE2"
+ let mounted =
+ try g#mount_options "discard" fs "/"; true
with _ -> false in
- if is_linux_x86_swap then (
- message (f_"Clearing Linux swap on %s") fs;
+ if mounted then (
+ message (f_"Trimming %s") fs;
- (* Don't use mkswap. Just preserve the header containing
- * the label, UUID and swap format version (libguestfs
- * mkswap may differ from guest's own).
- *)
- let header = g#pread_device fs 4096 0L in
- g#blkdiscard fs;
- if g#pwrite_device fs header 0L <> 4096 then
- error (f_"pwrite: short write restoring swap partition header")
+ g#fstrim "/"
+ ) else (
+ let is_linux_x86_swap =
+ (* Look for the signature for Linux swap on i386.
+ * Location depends on page size, so it definitely won't
+ * work on non-x86 architectures (eg. on PPC, page size is
+ * 64K). Also this avoids hibernated swap space: in those,
+ * the signature is moved to a different location.
+ *)
+ try g#pread_device fs 10 4086L = "SWAPSPACE2"
+ with _ -> false in
+
+ if is_linux_x86_swap then (
+ message (f_"Clearing Linux swap on %s") fs;
+
+ (* Don't use mkswap. Just preserve the header containing
+ * the label, UUID and swap format version (libguestfs
+ * mkswap may differ from guest's own).
+ *)
+ let header = g#pread_device fs 4096 0L in
+ g#blkdiscard fs;
+ if g#pwrite_device fs header 0L <> 4096 then
+ error (f_"pwrite: short write restoring swap partition header")
+ )
)
- )
- );
+ );
- g#umount_all ()
- )
- ) filesystems;
+ g#umount_all ()
+ )
+ ) filesystems in
(* Discard unused space in volume groups. *)
let vgs = g#vgs () in
let vgs = Array.to_list vgs in
let vgs = List.sort compare vgs in
- List.iter (
- fun vg ->
- if not (List.mem vg ignores) then (
- let lvname = String.random8 () in
- let lvdev = "/dev/" ^ vg ^ "/" ^ lvname in
- let created =
- try g#lvcreate_free lvname vg 100; true
- with _ -> false in
+ let tasks = tasks @
+ List.map (
+ fun vg () ->
+ if not (List.mem vg ignores) then (
+ let lvname = String.random8 () in
+ let lvdev = "/dev/" ^ vg ^ "/" ^ lvname in
- if created then (
- message (f_"Discard space in volgroup %s") vg;
+ let created =
+ try g#lvcreate_free lvname vg 100; true
+ with _ -> false in
- g#blkdiscard lvdev;
- g#sync ();
- g#lvremove lvdev
+ if created then (
+ message (f_"Discard space in volgroup %s") vg;
+
+ g#blkdiscard lvdev;
+ g#sync ();
+ g#lvremove lvdev
+ )
)
- )
- ) vgs;
+ ) vgs in
+
+ (* The above calls to List.map just created a list of tasks (thunks)
+ * to run. Now we actually run that code, keeping an eye on the
+ * state of the 'quit' flag.
+ *)
+ List.iter (
+ fun task ->
+ if not !quit then task ();
+ ) tasks;
g#shutdown ();
g#close ();
- (* Finished. *)
- message (f_"Sparsify in-place operation completed with no errors")
+ if not !quit then (
+ (* Finished. *)
+ message (f_"Sparsify in-place operation completed with no errors")
+ )
+ else (
+ (* User quit. *)
+ error (f_"quit (^C) at user request")
+ )
--
2.5.0
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