6:35 a.m.
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Mon, 22 Jun 2015 06:12:24 -0500
This is the second version of storage fixes.
V1 :
http://www.redhat.com/archives/libvir-list/2015-May/msg00050.html
Summary:
------------
Prerna Saxena (2):
Storage: Introduce shadow vol for refresh while the main vol builds.
Storage : Fix cloning of raw, sparse volumes
src/storage/storage_backend.c | 10 +++++-----
src/storage/storage_driver.c | 20 +++++++++++++-------
2 files changed, 18 insertions(+), 12 deletions(-)
Changelog:
--------------
1. Dropped patch 1/2 of v1 as per jtomko's suggestion; and introduced a
new patch for shadow-volume based cloning.
2. Reworked patch 2/2 incorporating review comments.
--
Regards,
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
6:37 a.m.
New subject: [libvirt] [PATCH 1/2] Storage: Introduce shadow vol for refresh while the main vol builds.
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Thu, 18 Jun 2015 05:05:09 -0500
Libvirt periodically refreshes all volumes in a storage pool, including
the volumes being cloned.
While cloning a storage volume from parent, we drop pool locks. Subsequent
volume refresh sometimes changes allocation for an ongoing copy, and leads
to corrupt images.
Fix: Introduce a shadow volume that isolates the volume object under refresh
from the base which has a copy ongoing.
Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
---
src/storage/storage_driver.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 57060ab..4980546 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1898,7 +1898,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
{
virStoragePoolObjPtr pool, origpool = NULL;
virStorageBackendPtr backend;
- virStorageVolDefPtr origvol = NULL, newvol = NULL;
+ virStorageVolDefPtr origvol = NULL, newvol = NULL, shadowvol = NULL;
virStorageVolPtr ret = NULL, volobj = NULL;
unsigned long long allocation;
int buildret;
@@ -2010,6 +2010,17 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
if (backend->createVol(obj->conn, pool, newvol) < 0)
goto cleanup;
+ /* Make a shallow copy of the 'defined' volume definition, since the
+ * original allocation value will change as the user polls 'info',
+ * but we only need the initial requested values
+ */
+ if (VIR_ALLOC(shadowvol) < 0) {
+ newvol = NULL;
+ goto cleanup;
+ }
+
+ memcpy(shadowvol, newvol, sizeof(*newvol));
+
pool->volumes.objs[pool->volumes.count++] = newvol;
volobj = virGetStorageVol(obj->conn, pool->def->name, newvol->name,
newvol->key, NULL, NULL);
@@ -2029,7 +2040,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
virStoragePoolObjUnlock(origpool);
}
- buildret = backend->buildVolFrom(obj->conn, pool, newvol, origvol, flags);
+ buildret = backend->buildVolFrom(obj->conn, pool, shadowvol, origvol, flags);
storageDriverLock();
virStoragePoolObjLock(pool);
--
1.8.3.1
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
7:51 a.m.
New subject: [libvirt] [PATCH 1/2] Storage: Introduce shadow vol for refresh while the main vol builds.
On Mon, Jun 22, 2015 at 05:07:26PM +0530, Prerna Saxena wrote:
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Thu, 18 Jun 2015 05:05:09 -0500
Libvirt periodically refreshes all volumes in a storage pool, including
the volumes being cloned.
While cloning a storage volume from parent, we drop pool locks. Subsequent
volume refresh sometimes changes allocation for an ongoing copy, and leads
to corrupt images.
Fix: Introduce a shadow volume that isolates the volume object under refresh
from the base which has a copy ongoing.
Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
---
src/storage/storage_driver.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 57060ab..4980546 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1898,7 +1898,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
{
virStoragePoolObjPtr pool, origpool = NULL;
virStorageBackendPtr backend;
- virStorageVolDefPtr origvol = NULL, newvol = NULL;
+ virStorageVolDefPtr origvol = NULL, newvol = NULL, shadowvol = NULL;
virStorageVolPtr ret = NULL, volobj = NULL;
unsigned long long allocation;
int buildret;
@@ -2010,6 +2010,17 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
if (backend->createVol(obj->conn, pool, newvol) < 0)
goto cleanup;
+ /* Make a shallow copy of the 'defined' volume definition, since the
+ * original allocation value will change as the user polls 'info',
+ * but we only need the initial requested values
+ */
+ if (VIR_ALLOC(shadowvol) < 0) {
+ newvol = NULL;
newvol has not been added to pool->volumes.objs yet, so we should free
it on the cleanup path. shadowvol should also be VIR_FREE'd.
+ goto cleanup;
+ }
+
+ memcpy(shadowvol, newvol, sizeof(*newvol));
+
pool->volumes.objs[pool->volumes.count++] = newvol;
volobj = virGetStorageVol(obj->conn, pool->def->name, newvol->name,
newvol->key, NULL, NULL);
@@ -2029,7 +2040,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
virStoragePoolObjUnlock(origpool);
}
- buildret = backend->buildVolFrom(obj->conn, pool, newvol, origvol, flags);
+ buildret = backend->buildVolFrom(obj->conn, pool, shadowvol, origvol, flags);
A few lines below, there is one more usage of newvol after the pool has
been unlocked: newvol->target.allocation
If the parallel volume refresh happened when the volume was not fully
allocated, this might not contain the intended allocation.
Using shadowvol->target.allocation will behave the same regardless of a
parallel refresh (even though the buildVolFrom function might not honor
the allocation exactly).
Jan
5 a.m.
New subject: [libvirt] [PATCH 1/2] Storage: Introduce shadow vol for refresh while the main vol builds.
Hi Jan,
Thanks for the review comments.
On Tuesday 23 June 2015 06:21 PM, Ján Tomko wrote:
On Mon, Jun 22, 2015 at 05:07:26PM +0530, Prerna Saxena wrote:
> From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
> Date: Thu, 18 Jun 2015 05:05:09 -0500
>
> Libvirt periodically refreshes all volumes in a storage pool, including
> the volumes being cloned.
> While cloning a storage volume from parent, we drop pool locks. Subsequent
> volume refresh sometimes changes allocation for an ongoing copy, and leads
> to corrupt images.
> Fix: Introduce a shadow volume that isolates the volume object under refresh
> from the base which has a copy ongoing.
>
> Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
> ---
> src/storage/storage_driver.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
> index 57060ab..4980546 100644
> --- a/src/storage/storage_driver.c
> +++ b/src/storage/storage_driver.c
> @@ -1898,7 +1898,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
> {
> virStoragePoolObjPtr pool, origpool = NULL;
> virStorageBackendPtr backend;
> - virStorageVolDefPtr origvol = NULL, newvol = NULL;
> + virStorageVolDefPtr origvol = NULL, newvol = NULL, shadowvol = NULL;
> virStorageVolPtr ret = NULL, volobj = NULL;
> unsigned long long allocation;
> int buildret;
> @@ -2010,6 +2010,17 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
> if (backend->createVol(obj->conn, pool, newvol) < 0)
> goto cleanup;
>
> + /* Make a shallow copy of the 'defined' volume definition, since the
> + * original allocation value will change as the user polls 'info',
> + * but we only need the initial requested values
> + */
> + if (VIR_ALLOC(shadowvol) < 0) {
> + newvol = NULL;
newvol has not been added to pool->volumes.objs yet, so we should free
it on the cleanup path. shadowvol should also be VIR_FREE'd.
Thanks, I'd missed this. Will be addressed in subsequent patch.
> + goto cleanup;
> + }
> +
> + memcpy(shadowvol, newvol, sizeof(*newvol));
> +
> pool->volumes.objs[pool->volumes.count++] = newvol;
> volobj = virGetStorageVol(obj->conn, pool->def->name, newvol->name,
> newvol->key, NULL, NULL);
> @@ -2029,7 +2040,7 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
> virStoragePoolObjUnlock(origpool);
> }
>
> - buildret = backend->buildVolFrom(obj->conn, pool, newvol, origvol,
flags);
> + buildret = backend->buildVolFrom(obj->conn, pool, shadowvol, origvol,
flags);
>
A few lines below, there is one more usage of newvol after the pool has
been unlocked: newvol->target.allocation
If the parallel volume refresh happened when the volume was not fully
allocated, this might not contain the intended allocation.
Using shadowvol->target.allocation will behave the same regardless of a
parallel refresh (even though the buildVolFrom function might not honor
the allocation exactly).
Right. The buildVolFrom() call completes an fsync and then returns. In my
experimental runs, a parallel refresh would always happen by the time I got to this point;
so this had missed me. But ofcourse
we can never say that for sure. Will fix in the next patch.
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
6:39 a.m.
New subject: [libvirt] [PATCH 2/2] Storage : Fix cloning of raw, sparse volumes
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Mon, 22 Jun 2015 02:54:32 -0500
When virsh vol-clone is attempted on a raw file where capacity > allocation,
the resulting cloned volume has a size that matches the virtual-size of
the parent; in place of matching its actual, disk size.
This patch fixes the cloned disk to have same _allocated_size_ as
the parent file from which it was cloned.
Ref: http://www.redhat.com/archives/libvir-list/2015-May/msg00050.html
Also fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1130739
Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
---
src/storage/storage_backend.c | 10 +++++-----
src/storage/storage_driver.c | 5 -----
2 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index ce59f63..c99b718 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -342,7 +342,7 @@ virStorageBackendCreateBlockFrom(virConnectPtr conn ATTRIBUTE_UNUSED,
goto cleanup;
}
- remain = vol->target.allocation;
+ remain = vol->target.capacity;
if (inputvol) {
int res = virStorageBackendCopyToFD(vol, inputvol,
@@ -397,7 +397,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
bool reflink_copy)
{
- bool need_alloc = true;
+ bool need_alloc = !(inputvol && (inputvol->target.capacity >
inputvol->target.allocation));
int ret = 0;
unsigned long long remain;
@@ -420,7 +420,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
* to writing zeroes block by block in case fallocate isn't
* available, and since we're going to copy data from another
* file it doesn't make sense to write the file twice. */
- if (vol->target.allocation) {
+ if (vol->target.allocation && need_alloc) {
if (fallocate(fd, 0, 0, vol->target.allocation) == 0) {
need_alloc = false;
} else if (errno != ENOSYS && errno != EOPNOTSUPP) {
@@ -433,14 +433,14 @@ createRawFile(int fd, virStorageVolDefPtr vol,
}
#endif
- remain = vol->target.allocation;
+ remain = vol->target.capacity;
if (inputvol) {
/* allow zero blocks to be skipped if we've requested sparse
* allocation (allocation < capacity) or we have already
* been able to allocate the required space. */
bool want_sparse = !need_alloc ||
- (vol->target.allocation < inputvol->target.capacity);
+ (inputvol->target.allocation < inputvol->target.capacity);
ret = virStorageBackendCopyToFD(vol, inputvol, fd, &remain,
want_sparse, reflink_copy);
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 4980546..c1dfe89 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1976,11 +1976,6 @@ storageVolCreateXMLFrom(virStoragePoolPtr obj,
if (newvol->target.capacity < origvol->target.capacity)
newvol->target.capacity = origvol->target.capacity;
- /* Make sure allocation is at least as large as the destination cap,
- * to make absolutely sure we copy all possible contents */
- if (newvol->target.allocation < origvol->target.capacity)
- newvol->target.allocation = origvol->target.capacity;
-
if (!backend->buildVolFrom) {
virReportError(VIR_ERR_NO_SUPPORT,
"%s", _("storage pool does not support"
--
1.8.3.1
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
7:59 a.m.
New subject: [libvirt] [PATCH 2/2] Storage : Fix cloning of raw, sparse volumes
On Mon, Jun 22, 2015 at 05:09:18PM +0530, Prerna Saxena wrote:
From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
Date: Mon, 22 Jun 2015 02:54:32 -0500
When virsh vol-clone is attempted on a raw file where capacity > allocation,
the resulting cloned volume has a size that matches the virtual-size of
the parent; in place of matching its actual, disk size.
This patch fixes the cloned disk to have same _allocated_size_ as
the parent file from which it was cloned.
Ref: http://www.redhat.com/archives/libvir-list/2015-May/msg00050.html
Also fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1130739
Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
---
src/storage/storage_backend.c | 10 +++++-----
src/storage/storage_driver.c | 5 -----
2 files changed, 5 insertions(+), 10 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index ce59f63..c99b718 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -342,7 +342,7 @@ virStorageBackendCreateBlockFrom(virConnectPtr conn
ATTRIBUTE_UNUSED,
goto cleanup;
}
- remain = vol->target.allocation;
+ remain = vol->target.capacity;
if (inputvol) {
int res = virStorageBackendCopyToFD(vol, inputvol,
@@ -397,7 +397,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
virStorageVolDefPtr inputvol,
bool reflink_copy)
{
- bool need_alloc = true;
+ bool need_alloc = !(inputvol && (inputvol->target.capacity >
inputvol->target.allocation));
Comparing 'inputvol->target.capacity > vol->target.allocation' would
allow creating a sparse volume from a non-sparse one and vice-versa
by specifying the correct allocation.
int ret = 0;
unsigned long long remain;
@@ -420,7 +420,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
* to writing zeroes block by block in case fallocate isn't
* available, and since we're going to copy data from another
* file it doesn't make sense to write the file twice. */
- if (vol->target.allocation) {
+ if (vol->target.allocation && need_alloc) {
if (fallocate(fd, 0, 0, vol->target.allocation) == 0) {
need_alloc = false;
} else if (errno != ENOSYS && errno != EOPNOTSUPP) {
@@ -433,14 +433,14 @@ createRawFile(int fd, virStorageVolDefPtr vol,
}
#endif
- remain = vol->target.allocation;
+ remain = vol->target.capacity;
if (inputvol) {
/* allow zero blocks to be skipped if we've requested sparse
* allocation (allocation < capacity) or we have already
* been able to allocate the required space. */
bool want_sparse = !need_alloc ||
- (vol->target.allocation < inputvol->target.capacity);
+ (inputvol->target.allocation < inputvol->target.capacity);
If allocation < capacity, then need_alloc is already false.
Jan
5:08 a.m.
New subject: [libvirt] [PATCH 2/2] Storage : Fix cloning of raw, sparse volumes
On Tuesday 23 June 2015 06:29 PM, Ján Tomko wrote:
On Mon, Jun 22, 2015 at 05:09:18PM +0530, Prerna Saxena wrote:
> From: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
> Date: Mon, 22 Jun 2015 02:54:32 -0500
>
> When virsh vol-clone is attempted on a raw file where capacity > allocation,
> the resulting cloned volume has a size that matches the virtual-size of
> the parent; in place of matching its actual, disk size.
> This patch fixes the cloned disk to have same _allocated_size_ as
> the parent file from which it was cloned.
>
> Ref: http://www.redhat.com/archives/libvir-list/2015-May/msg00050.html
>
> Also fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1130739
>
> Signed-off-by: Prerna Saxena <prerna(a)linux.vnet.ibm.com>
> ---
> src/storage/storage_backend.c | 10 +++++-----
> src/storage/storage_driver.c | 5 -----
> 2 files changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index ce59f63..c99b718 100644
> --- a/src/storage/storage_backend.c
> +++ b/src/storage/storage_backend.c
> @@ -342,7 +342,7 @@ virStorageBackendCreateBlockFrom(virConnectPtr conn
ATTRIBUTE_UNUSED,
> goto cleanup;
> }
>
> - remain = vol->target.allocation;
> + remain = vol->target.capacity;
>
> if (inputvol) {
> int res = virStorageBackendCopyToFD(vol, inputvol,
> @@ -397,7 +397,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
> virStorageVolDefPtr inputvol,
> bool reflink_copy)
> {
> - bool need_alloc = true;
> + bool need_alloc = !(inputvol && (inputvol->target.capacity >
inputvol->target.allocation));
Comparing 'inputvol->target.capacity > vol->target.allocation' would
allow creating a sparse volume from a non-sparse one and vice-versa
by specifying the correct allocation.
Ok, I was not sure if libvirt wanted to do that.
If the parent volume is a sparse volume, I'd expect the cloned volume to be sparse
too. Likewise, for a non-sparse parent, the cloned volume should also be non-sparse.
Should that not be something we
honour in libvirt, when we clone ?
> int ret = 0;
> unsigned long long remain;
>
> @@ -420,7 +420,7 @@ createRawFile(int fd, virStorageVolDefPtr vol,
> * to writing zeroes block by block in case fallocate isn't
> * available, and since we're going to copy data from another
> * file it doesn't make sense to write the file twice. */
> - if (vol->target.allocation) {
> + if (vol->target.allocation && need_alloc) {
> if (fallocate(fd, 0, 0, vol->target.allocation) == 0) {
> need_alloc = false;
> } else if (errno != ENOSYS && errno != EOPNOTSUPP) {
> @@ -433,14 +433,14 @@ createRawFile(int fd, virStorageVolDefPtr vol,
> }
> #endif
>
> - remain = vol->target.allocation;
> + remain = vol->target.capacity;
>
> if (inputvol) {
> /* allow zero blocks to be skipped if we've requested sparse
> * allocation (allocation < capacity) or we have already
> * been able to allocate the required space. */
> bool want_sparse = !need_alloc ||
> - (vol->target.allocation < inputvol->target.capacity);
> + (inputvol->target.allocation < inputvol->target.capacity);
If allocation < capacity, then need_alloc is already false.
I was trying to accomodate the original usecase of need_alloc, but you are right.
This will go away in the next version of this series, which I will post shortly.
--
Prerna Saxena
Linux Technology Centre,
IBM Systems and Technology Lab,
Bangalore, India
3441
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6 comments
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