Re: [PATCH v2] block: Use LVM tools for LV block device truncation
On Thu, Mar 14, 2024 at 06:25:00PM +0100, Alexander Ivanov wrote:
>
>
> On 3/14/24 13:44, Daniel P. Berrangé wrote:
> > On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
> > > If a block device is an LVM logical volume we can resize it using
> > > standard LVM tools.
> > >
> > > Add a helper to detect if a device is a DM device. In raw_co_truncate()
> > > check if the block device is DM and resize it executing lvresize.
> > >
> > > Signed-off-by: Alexander Ivanov
> > > ---
> > > block/file-posix.c | 61 ++
> > > 1 file changed, 61 insertions(+)
> > >
> > > diff --git a/block/file-posix.c b/block/file-posix.c
> > > index 35684f7e21..5f07d98aa5 100644
> > > --- a/block/file-posix.c
> > > +++ b/block/file-posix.c
> > > @@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd,
> > > int64_t offset,
> > > return raw_thread_pool_submit(handle_aiocb_truncate, );
> > > }
> > > static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t
> > > offset,
> > > bool exact, PreallocMode
> > > prealloc,
> > > BdrvRequestFlags flags, Error
> > > **errp)
> > > @@ -2670,6 +2702,35 @@ static int coroutine_fn
> > > raw_co_truncate(BlockDriverState *bs, int64_t offset,
> > > if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
> > > int64_t cur_length = raw_getlength(bs);
> > > +/*
> > > + * Try to resize an LVM device using LVM tools.
> > > + */
> > > +if (device_is_dm() && offset > 0) {
> > > +int spawn_flags = G_SPAWN_SEARCH_PATH |
> > > G_SPAWN_STDOUT_TO_DEV_NULL;
> > > +int status;
> > > +bool success;
> > > +char *err;
> > > +GError *gerr = NULL;
> > > +g_autofree char *size_str = g_strdup_printf("%ldB", offset);
> > offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
> > this will break on 32-bit platforms. Try PRId64 instead.
> >
> > > +const char *cmd[] = {"lvresize", "-f", "-L",
> > > + size_str, bs->filename, NULL};
> > > +
> > > +success = g_spawn_sync(NULL, (gchar **)cmd, NULL,
> > > spawn_flags,
> > > + NULL, NULL, NULL, , ,
> > > );
> > > +
> > > +if (success && WEXITSTATUS(status) == 0) {
> > > +return 0;
> > > +}
> > We should probably check 'g_spawn_check_wait_status' rather than
> > WEXITSTATUS, as this then gives us further eror message details
> > that
> Thank you.
> I think it would be better to use 'g_spawn_check_exit_status' because there
> is no
> 'g_spawn_check_wait_status' in glib before 2.70 and even in 2.78 it leads to
> 'g_spawn_check_wait_status is deprecated: Not available before 2.70' error.
Ah yes, well spotted.
With regards,
Daniel
--
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Re: [PATCH v2] block: Use LVM tools for LV block device truncation
On 3/14/24 13:44, Daniel P. Berrangé wrote:
On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
If a block device is an LVM logical volume we can resize it using
standard LVM tools.
Add a helper to detect if a device is a DM device. In raw_co_truncate()
check if the block device is DM and resize it executing lvresize.
Signed-off-by: Alexander Ivanov
---
block/file-posix.c | 61 ++
1 file changed, 61 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 35684f7e21..5f07d98aa5 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd,
int64_t offset,
return raw_thread_pool_submit(handle_aiocb_truncate, );
}
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, Error **errp)
@@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState
*bs, int64_t offset,
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
int64_t cur_length = raw_getlength(bs);
+/*
+ * Try to resize an LVM device using LVM tools.
+ */
+if (device_is_dm() && offset > 0) {
+int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
+int status;
+bool success;
+char *err;
+GError *gerr = NULL;
+g_autofree char *size_str = g_strdup_printf("%ldB", offset);
offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
this will break on 32-bit platforms. Try PRId64 instead.
+const char *cmd[] = {"lvresize", "-f", "-L",
+ size_str, bs->filename, NULL};
+
+success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
+ NULL, NULL, NULL, , , );
+
+if (success && WEXITSTATUS(status) == 0) {
+return 0;
+}
We should probably check 'g_spawn_check_wait_status' rather than
WEXITSTATUS, as this then gives us further eror message details
that
Thank you.
I think it would be better to use 'g_spawn_check_exit_status' because
there is no
'g_spawn_check_wait_status' in glib before 2.70 and even in 2.78 it
leads to
'g_spawn_check_wait_status is deprecated: Not available before 2.70' error.
+
+if (!success) {
+error_setg(errp, "lvresize execution error: %s",
gerr->message);
+} else {
+error_setg(errp, "%s", err);
...we would also include here, such as the exit code or terminal
signal.
+}
+
+return -EINVAL;
+}
+
if (offset != cur_length && exact) {
error_setg(errp, "Cannot resize device files");
return -ENOTSUP;
--
2.40.1
With regards,
Daniel
--
Best regards,
Alexander Ivanov
Re: [PATCH v2] block: Use LVM tools for LV block device truncation
On Wed, Mar 13, 2024 at 11:43:27AM +0100, Alexander Ivanov wrote:
> If a block device is an LVM logical volume we can resize it using
> standard LVM tools.
>
> Add a helper to detect if a device is a DM device. In raw_co_truncate()
> check if the block device is DM and resize it executing lvresize.
>
> Signed-off-by: Alexander Ivanov
> ---
> block/file-posix.c | 61 ++
> 1 file changed, 61 insertions(+)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 35684f7e21..5f07d98aa5 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd,
> int64_t offset,
> return raw_thread_pool_submit(handle_aiocb_truncate, );
> }
> static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
> bool exact, PreallocMode prealloc,
> BdrvRequestFlags flags, Error **errp)
> @@ -2670,6 +2702,35 @@ static int coroutine_fn
> raw_co_truncate(BlockDriverState *bs, int64_t offset,
> if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
> int64_t cur_length = raw_getlength(bs);
>
> +/*
> + * Try to resize an LVM device using LVM tools.
> + */
> +if (device_is_dm() && offset > 0) {
> +int spawn_flags = G_SPAWN_SEARCH_PATH |
> G_SPAWN_STDOUT_TO_DEV_NULL;
> +int status;
> +bool success;
> +char *err;
> +GError *gerr = NULL;
> +g_autofree char *size_str = g_strdup_printf("%ldB", offset);
offset is 64-bit, but '%ld' is not guaranteed to be 64-bit. I expect
this will break on 32-bit platforms. Try PRId64 instead.
> +const char *cmd[] = {"lvresize", "-f", "-L",
> + size_str, bs->filename, NULL};
> +
> +success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
> + NULL, NULL, NULL, , , );
> +
> +if (success && WEXITSTATUS(status) == 0) {
> +return 0;
> +}
We should probably check 'g_spawn_check_wait_status' rather than
WEXITSTATUS, as this then gives us further eror message details
that
> +
> +if (!success) {
> +error_setg(errp, "lvresize execution error: %s",
> gerr->message);
> +} else {
> +error_setg(errp, "%s", err);
...we would also include here, such as the exit code or terminal
signal.
> +}
> +
> +return -EINVAL;
> +}
> +
> if (offset != cur_length && exact) {
> error_setg(errp, "Cannot resize device files");
> return -ENOTSUP;
> --
> 2.40.1
>
>
With regards,
Daniel
--
|: https://berrange.com -o-https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o-https://fstop138.berrange.com :|
|: https://entangle-photo.org-o-https://www.instagram.com/dberrange :|
[PATCH v2] block: Use LVM tools for LV block device truncation
If a block device is an LVM logical volume we can resize it using
standard LVM tools.
Add a helper to detect if a device is a DM device. In raw_co_truncate()
check if the block device is DM and resize it executing lvresize.
Signed-off-by: Alexander Ivanov
---
block/file-posix.c | 61 ++
1 file changed, 61 insertions(+)
diff --git a/block/file-posix.c b/block/file-posix.c
index 35684f7e21..5f07d98aa5 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -2642,6 +2642,38 @@ raw_regular_truncate(BlockDriverState *bs, int fd,
int64_t offset,
return raw_thread_pool_submit(handle_aiocb_truncate, );
}
+static bool device_is_dm(struct stat *st)
+{
+unsigned int maj, maj2;
+char line[32], devname[16];
+bool ret = false;
+FILE *f;
+
+if (!S_ISBLK(st->st_mode)) {
+return false;
+}
+
+f = fopen("/proc/devices", "r");
+if (!f) {
+return false;
+}
+
+maj = major(st->st_rdev);
+
+while (fgets(line, sizeof(line), f)) {
+if (sscanf(line, "%u %15s", , devname) != 2) {
+continue;
+}
+if (strcmp(devname, "device-mapper") == 0) {
+ret = (maj == maj2);
+break;
+}
+}
+
+fclose(f);
+return ret;
+}
+
static int coroutine_fn raw_co_truncate(BlockDriverState *bs, int64_t offset,
bool exact, PreallocMode prealloc,
BdrvRequestFlags flags, Error **errp)
@@ -2670,6 +2702,35 @@ static int coroutine_fn raw_co_truncate(BlockDriverState
*bs, int64_t offset,
if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
int64_t cur_length = raw_getlength(bs);
+/*
+ * Try to resize an LVM device using LVM tools.
+ */
+if (device_is_dm() && offset > 0) {
+int spawn_flags = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL;
+int status;
+bool success;
+char *err;
+GError *gerr = NULL;
+g_autofree char *size_str = g_strdup_printf("%ldB", offset);
+const char *cmd[] = {"lvresize", "-f", "-L",
+ size_str, bs->filename, NULL};
+
+success = g_spawn_sync(NULL, (gchar **)cmd, NULL, spawn_flags,
+ NULL, NULL, NULL, , , );
+
+if (success && WEXITSTATUS(status) == 0) {
+return 0;
+}
+
+if (!success) {
+error_setg(errp, "lvresize execution error: %s",
gerr->message);
+} else {
+error_setg(errp, "%s", err);
+}
+
+return -EINVAL;
+}
+
if (offset != cur_length && exact) {
error_setg(errp, "Cannot resize device files");
return -ENOTSUP;
--
2.40.1
