debian/patches/pve/0047-PVE-add-zero-block-handling-to-PBS-dump-callback.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Stefan Reiter <s.reiter@proxmox.com>
   3 Date: Thu, 13 Aug 2020 13:50:27 +0200
   4 Subject: [PATCH] PVE: add zero block handling to PBS dump callback
   5
   6 Both the PBS and VMA dump callbacks assume that a NULL pointer can be
   7 passed as *pbuf, but that never happens, as backup-dump.c calls this
   8 function with contents of an iovec.
   9
  10 So first, remove that assumption and add an 'assert' to verify.
  11
  12 Secondly, while the vma-writer already does the buffer_is_zero check
  13 internally, for PBS we relied on that non-existant behaviour for zero
  14 chunks, so do the buffer_is_zero check manually and pass NULL to the
  15 rust lib in case it is true.
  16
  17 Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
  18 ---
  19  pve-backup.c | 14 +++++++++-----
  20  1 file changed, 9 insertions(+), 5 deletions(-)
  21
  22 diff --git a/pve-backup.c b/pve-backup.c
  23 index 3eba85506a..40c2697b37 100644
  24 --- a/pve-backup.c
  25 +++ b/pve-backup.c
  26 @@ -8,6 +8,7 @@
  27  #include "block/blockjob.h"
  28  #include "qapi/qapi-commands-block.h"
  29  #include "qapi/qmp/qerror.h"
  30 +#include "qemu/cutils.h"
  31
  32  /* PVE backup state and related function */
  33
  34 @@ -136,10 +137,13 @@ pvebackup_co_dump_pbs_cb(
  35      PVEBackupDevInfo *di = opaque;
  36
  37      assert(backup_state.pbs);
  38 +    assert(buf);
  39
  40      Error *local_err = NULL;
  41      int pbs_res = -1;
  42
  43 +    bool is_zero_block = size == di->block_size && buffer_is_zero(buf, size);
  44 +
  45      qemu_co_mutex_lock(&backup_state.dump_callback_mutex);
  46
  47      // avoid deadlock if job is cancelled
  48 @@ -155,7 +159,8 @@ pvebackup_co_dump_pbs_cb(
  49          uint64_t to_transfer = left < di->block_size ? left : di->block_size;
  50
  51          pbs_res = proxmox_backup_co_write_data(backup_state.pbs, di->dev_id,
  52 -            buf ? buf + transferred : NULL, start + transferred, to_transfer, &local_err);
  53 +            is_zero_block ? NULL : buf + transferred, start + transferred,
  54 +            to_transfer, &local_err);
  55          transferred += to_transfer;
  56
  57          if (pbs_res < 0) {
  58 @@ -168,7 +173,7 @@ pvebackup_co_dump_pbs_cb(
  59      }
  60
  61      qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
  62 -    pvebackup_add_transfered_bytes(size, !buf ? size : 0, reused);
  63 +    pvebackup_add_transfered_bytes(size, is_zero_block ? size : 0, reused);
  64
  65      return size;
  66  }
  67 @@ -190,6 +195,7 @@ pvebackup_co_dump_vma_cb(
  68      int ret = -1;
  69
  70      assert(backup_state.vmaw);
  71 +    assert(buf);
  72
  73      uint64_t remaining = size;
  74
  75 @@ -216,9 +222,7 @@ pvebackup_co_dump_vma_cb(
  76          qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
  77
  78          ++cluster_num;
  79 -        if (buf) {
  80 -            buf += VMA_CLUSTER_SIZE;
  81 -        }
  82 +        buf += VMA_CLUSTER_SIZE;
  83          if (ret < 0) {
  84              Error *local_err = NULL;
  85              vma_writer_error_propagate(backup_state.vmaw, &local_err);