[pbs-devel] [PATCH qemu] PVE: handle PBS write callback with big blocks correctly
Stefan Reiter
s.reiter at proxmox.com
Tue Jul 14 15:17:17 CEST 2020
Under certain conditions QEMU will push more than the given blocksize
into the callback at once. Handle it like VMA does, by iterating the
data in PROXMOX_BACKUP_DEFAULT_CHUNK_SIZE (or smaller, for last one)
sized blocks.
Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---
As briefly tested by Fabian, it seems to fix the original issue.
pve-backup.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/pve-backup.c b/pve-backup.c
index 77eb475563..4d423611e1 100644
--- a/pve-backup.c
+++ b/pve-backup.c
@@ -147,17 +147,29 @@ pvebackup_co_dump_pbs_cb(
return -1;
}
- pbs_res = proxmox_backup_co_write_data(backup_state.pbs, di->dev_id, buf, start, size, &local_err);
- qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
+ uint64_t transferred = 0;
+ uint64_t reused = 0;
+ while (transferred < size) {
+ uint64_t left = size - transferred;
+ uint64_t to_transfer = left < PROXMOX_BACKUP_DEFAULT_CHUNK_SIZE ?
+ left : PROXMOX_BACKUP_DEFAULT_CHUNK_SIZE;
- if (pbs_res < 0) {
- pvebackup_propagate_error(local_err);
- return pbs_res;
- } else {
- size_t reused = (pbs_res == 0) ? size : 0;
- pvebackup_add_transfered_bytes(size, !buf ? size : 0, reused);
+ pbs_res = proxmox_backup_co_write_data(backup_state.pbs, di->dev_id,
+ buf ? buf + transferred : NULL, start + transferred, to_transfer, &local_err);
+ transferred += to_transfer;
+
+ if (pbs_res < 0) {
+ pvebackup_propagate_error(local_err);
+ qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
+ return pbs_res;
+ }
+
+ reused += pbs_res == 0 ? to_transfer : 0;
}
+ qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
+ pvebackup_add_transfered_bytes(size, !buf ? size : 0, reused);
+
return size;
}
--
2.20.1
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