block: Add and use bdrv_replace_in_backing_chain()

This cleans up the mess we left behind in the mirror code after the
previous patch. Instead of using bdrv_swap(), just change pointers.

The interface change of the mirror job that callers must consider is
that after job completion, their local BDS pointers still point to the
same node now. qemu-img must change its code accordingly (which makes it
easier to understand); the other callers stays unchanged because after
completion they don't do anything with the BDS, but just with the job,
and the job is still owned by the source BDS.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
4 files changed
tree: 775e62f32f4e2aa77a60a952212044060f11bcdd
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. crypto/
  6. default-configs/
  7. disas/
  8. docs/
  9. fpu/
  10. fsdev/
  11. gdb-xml/
  12. hw/
  13. include/
  14. libdecnumber/
  15. linux-headers/
  16. linux-user/
  17. migration/
  18. net/
  19. pc-bios/
  20. po/
  21. qapi/
  22. qga/
  23. qobject/
  24. qom/
  25. roms/
  26. scripts/
  27. slirp/
  28. stubs/
  29. target-alpha/
  30. target-arm/
  31. target-cris/
  32. target-i386/
  33. target-lm32/
  34. target-m68k/
  35. target-microblaze/
  36. target-mips/
  37. target-moxie/
  38. target-openrisc/
  39. target-ppc/
  40. target-s390x/
  41. target-sh4/
  42. target-sparc/
  43. target-tilegx/
  44. target-tricore/
  45. target-unicore32/
  46. target-xtensa/
  47. tcg/
  48. tests/
  49. trace/
  50. ui/
  51. util/
  52. .dir-locals.el
  53. .exrc
  54. .gitignore
  55. .gitmodules
  56. .mailmap
  57. .travis.yml
  58. accel.c
  59. aio-posix.c
  60. aio-win32.c
  61. arch_init.c
  62. async.c
  63. balloon.c
  64. block.c
  65. blockdev-nbd.c
  66. blockdev.c
  67. blockjob.c
  68. bootdevice.c
  69. bt-host.c
  70. bt-vhci.c
  71. Changelog
  72. CODING_STYLE
  73. configure
  74. COPYING
  75. COPYING.LIB
  76. coroutine-gthread.c
  77. coroutine-sigaltstack.c
  78. coroutine-ucontext.c
  79. coroutine-win32.c
  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. nbd.c
  112. numa.c
  113. os-posix.c
  114. os-win32.c
  115. page_cache.c
  116. qapi-schema.json
  117. qdev-monitor.c
  118. qdict-test-data.txt
  119. qemu-bridge-helper.c
  120. qemu-char.c
  121. qemu-coroutine-io.c
  122. qemu-coroutine-lock.c
  123. qemu-coroutine-sleep.c
  124. qemu-coroutine.c
  125. qemu-doc.texi
  126. qemu-ga.texi
  127. qemu-img-cmds.hx
  128. qemu-img.c
  129. qemu-img.texi
  130. qemu-io-cmds.c
  131. qemu-io.c
  132. qemu-log.c
  133. qemu-nbd.c
  134. qemu-nbd.texi
  135. qemu-options-wrapper.h
  136. qemu-options.h
  137. qemu-options.hx
  138. qemu-seccomp.c
  139. qemu-tech.texi
  140. qemu-timer.c
  141. qemu.nsi
  142. qemu.sasl
  143. qjson.c
  144. qmp-commands.hx
  145. qmp.c
  146. qtest.c
  147. README
  148. rules.mak
  149. softmmu_template.h
  150. spice-qemu-char.c
  151. tcg-runtime.c
  152. tci.c
  153. thread-pool.c
  154. thunk.c
  155. tpm.c
  156. trace-events
  157. translate-all.c
  158. translate-all.h
  159. translate-common.c
  160. user-exec.c
  161. VERSION
  162. version.rc
  163. vl.c
  164. xen-common-stub.c
  165. xen-common.c
  166. xen-hvm-stub.c
  167. xen-hvm.c
  168. xen-mapcache.c