block: Convert block job core to BlockBackend

This adds a new BlockBackend field to the BlockJob struct, which
coexists with the BlockDriverState while converting the individual jobs.

When creating a block job, a new BlockBackend is created on top of the
given BlockDriverState, and it is destroyed when the BlockJob ends. The
reference to the BDS is now held by the BlockBackend instead of calling
bdrv_ref/unref manually.

We have to be careful when we use bdrv_replace_in_backing_chain() in
block jobs because this changes the BDS that job->blk points to. At the
moment block jobs are too tightly coupled with their BDS, so that moving
a job to another BDS isn't easily possible; therefore, we need to just
manually undo this change afterwards.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
3 files changed
tree: 4c4b068514226799720a463ebee7016a592285e2
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. contrib/
  6. crypto/
  7. default-configs/
  8. disas/
  9. docs/
  10. fpu/
  11. fsdev/
  12. gdb-xml/
  13. hw/
  14. include/
  15. io/
  16. libdecnumber/
  17. linux-headers/
  18. linux-user/
  19. migration/
  20. nbd/
  21. net/
  22. pc-bios/
  23. po/
  24. qapi/
  25. qga/
  26. qobject/
  27. qom/
  28. replay/
  29. roms/
  30. scripts/
  31. slirp/
  32. stubs/
  33. target-alpha/
  34. target-arm/
  35. target-cris/
  36. target-i386/
  37. target-lm32/
  38. target-m68k/
  39. target-microblaze/
  40. target-mips/
  41. target-moxie/
  42. target-openrisc/
  43. target-ppc/
  44. target-s390x/
  45. target-sh4/
  46. target-sparc/
  47. target-tilegx/
  48. target-tricore/
  49. target-unicore32/
  50. target-xtensa/
  51. tcg/
  52. tests/
  53. trace/
  54. ui/
  55. util/
  56. .dir-locals.el
  57. .exrc
  58. .gitignore
  59. .gitmodules
  60. .mailmap
  61. .travis.yml
  62. accel.c
  63. aio-posix.c
  64. aio-win32.c
  65. arch_init.c
  66. async.c
  67. balloon.c
  68. block.c
  69. blockdev-nbd.c
  70. blockdev.c
  71. blockjob.c
  72. bootdevice.c
  73. bt-host.c
  74. bt-vhci.c
  75. Changelog
  76. CODING_STYLE
  77. configure
  78. COPYING
  79. COPYING.LIB
  80. cpu-exec-common.c
  81. cpu-exec.c
  82. cpus.c
  83. cputlb.c
  84. device-hotplug.c
  85. device_tree.c
  86. disas.c
  87. dma-helpers.c
  88. dump.c
  89. exec.c
  90. gdbstub.c
  91. HACKING
  92. hmp-commands-info.hx
  93. hmp-commands.hx
  94. hmp.c
  95. hmp.h
  96. iohandler.c
  97. ioport.c
  98. iothread.c
  99. kvm-all.c
  100. kvm-stub.c
  101. LICENSE
  102. main-loop.c
  103. MAINTAINERS
  104. Makefile
  105. Makefile.objs
  106. Makefile.target
  107. memory.c
  108. memory_mapping.c
  109. module-common.c
  110. monitor.c
  111. numa.c
  112. os-posix.c
  113. os-win32.c
  114. page_cache.c
  115. qapi-schema.json
  116. qdev-monitor.c
  117. qdict-test-data.txt
  118. qemu-bridge-helper.c
  119. qemu-char.c
  120. qemu-doc.texi
  121. qemu-ga.texi
  122. qemu-img-cmds.hx
  123. qemu-img.c
  124. qemu-img.texi
  125. qemu-io-cmds.c
  126. qemu-io.c
  127. qemu-nbd.c
  128. qemu-nbd.texi
  129. qemu-options-wrapper.h
  130. qemu-options.h
  131. qemu-options.hx
  132. qemu-seccomp.c
  133. qemu-tech.texi
  134. qemu-timer.c
  135. qemu.nsi
  136. qemu.sasl
  137. qmp-commands.hx
  138. qmp.c
  139. qtest.c
  140. README
  141. rules.mak
  142. softmmu_template.h
  143. spice-qemu-char.c
  144. tcg-runtime.c
  145. tci.c
  146. thread-pool.c
  147. thunk.c
  148. tpm.c
  149. trace-events
  150. translate-all.c
  151. translate-all.h
  152. translate-common.c
  153. user-exec.c
  154. VERSION
  155. version.rc
  156. vl.c
  157. xen-common-stub.c
  158. xen-common.c
  159. xen-hvm-stub.c
  160. xen-hvm.c
  161. xen-mapcache.c