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, &acb); > > > } > > > 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(&st) && 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, &err, &status, > > > &gerr); > > > + > > > +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 -- |: 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 :|
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, &acb); } 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(&st) && 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, &err, &status, &gerr); + +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, &acb); > } > 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(&st) && 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, &err, &status, &gerr); > + > +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, &acb); } +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", &maj2, 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(&st) && 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, &err, &status, &gerr); + +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