Re: [libvirt] [PATCH 3/5] storage: Add TRIM algorithm to storage volume API

This new algorithm adds support for wiping volumes using TRIM. It does not overwrite all the data in a volume, but it tells the backing storage pool/driver that all bytes in a volume can be discarded. It depends on the backing storage pool how this is handled. A SCSI backend might send UNMAP commands to remove all data present on a LUN. A Ceph backend might use rbd_discard() to instruct the Ceph cluster that all data on that RBD volume can be discarded. Signed-off-by: Wido den Hollander <wido(a)widodh.nl&gt; --- include/libvirt/libvirt-storage.h | 3 +++ src/storage/storage_backend.c | 4 ++++ tools/virsh-volume.c | 2 +- tools/virsh.pod | 1 + 4 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/libvirt/libvirt-storage.h b/include/libvirt/libvirt-storage.h index 2c55c93..232b4d3 100644 --- a/include/libvirt/libvirt-storage.h +++ b/include/libvirt/libvirt-storage.h @@ -153,6 +153,9 @@ typedef enum { VIR_STORAGE_VOL_WIPE_ALG_RANDOM = 8, /* 1-pass random */ + VIR_STORAGE_VOL_WIPE_ALG_TRIM = 9, /* 1-pass, trim all data on the + volume by using TRIM or DISCARD */ + # ifdef VIR_ENUM_SENTINELS VIR_STORAGE_VOL_WIPE_ALG_LAST /* diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 15e9109..1bb44a7 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -2065,6 +2065,7 @@ virStorageBackendVolWipeLocal(virConnectPtr conn ATTRIBUTE_UNUSED, VIR_STORAGE_VOL_WIPE_ALG_PFITZNER7 | VIR_STORAGE_VOL_WIPE_ALG_PFITZNER33 | VIR_STORAGE_VOL_WIPE_ALG_RANDOM | + VIR_STORAGE_VOL_WIPE_ALG_TRIM | VIR_STORAGE_VOL_WIPE_ALG_LAST, -1); VIR_DEBUG("Wiping volume with path '%s' and algorithm %u", @@ -2112,6 +2113,9 @@ virStorageBackendVolWipeLocal(virConnectPtr conn ATTRIBUTE_UNUSED, case VIR_STORAGE_VOL_WIPE_ALG_RANDOM: alg_char = "random"; break; + case VIR_STORAGE_VOL_WIPE_ALG_TRIM: + alg_char = "trim"; + break;

default: virReportError(VIR_ERR_INVALID_ARG, _("unsupported algorithm %d"), diff --git a/tools/virsh-volume.c b/tools/virsh-volume.c index 661c876..35f0cbd 100644 --- a/tools/virsh-volume.c +++ b/tools/virsh-volume.c @@ -906,7 +906,7 @@ static const vshCmdOptDef opts_vol_wipe[] = { VIR_ENUM_DECL(virStorageVolWipeAlgorithm) VIR_ENUM_IMPL(virStorageVolWipeAlgorithm, VIR_STORAGE_VOL_WIPE_ALG_LAST, "zero", "nnsa", "dod", "bsi", "gutmann", "schneier", - "pfitzner7", "pfitzner33", "random"); + "pfitzner7", "pfitzner33", "random", "trim"); static bool cmdVolWipe(vshControl *ctl, const vshCmd *cmd) diff --git a/tools/virsh.pod b/tools/virsh.pod index e830c59..b259507 100644 --- a/tools/virsh.pod +++ b/tools/virsh.pod @@ -3546,6 +3546,7 @@ B<Supported algorithms> pfitzner7 - Roy Pfitzner's 7-random-pass method: random x7. pfitzner33 - Roy Pfitzner's 33-random-pass method: random x33. random - 1-pass pattern: random. + trim - 1-pass trimming the volume using TRIM or DISCARD B<Note>: The availability of algorithms may be limited by the version of the C<scrub> binary installed on the host.