[Qemu-devel] [PATCH v4 0/8] block: Integrate bdrv_file_open() into bdrv_open()

[Max Reitz <mreitz@redhat.com>]

bdrv_file_open() is now nearly a subset of bdrv_open(), except for the
fact that bdrv_file_open() is for protocols and bdrv_open() for block
drivers. It is possible to use bdrv_file_open() with a block driver, but
in that case that block driver must be explicitly specified.

Due to these great similarities, bdrv_file_open() can be integrated and
made a special case of bdrv_open(). If the flag BDRV_O_PROTOCOL is
specified, bdrv_open() will now do what bdrv_file_open() used to do:
Auto-detecting a protocol instead of a block driver.

This series implements this and changes all calls to bdrv_file_open() to
bdrv_open() calls with BDRV_O_PROTOCOL specified.

Note that this flag cannot be discerned automatically since it is
impossible for bdrv_open() to know by itself whether a given file should
be opened with or without the format layer involved: Both are valid
alternatives. Therefore, it still has to be specified by the user.


v4 (rebased on Kevin's block branch):
 - patch 2: use Benoît's bdrv_lookup_bs() instead of bdrv_find()
 - patch 4: resolved rebase conflict (the v3 hunk removed a bdrv_find(),
   whereas now it is a bdrv_lookup_bs())

v3:
 - patch 1:
   - Kevin: add assert(pbs) and assert(*pbs == NULL) in
     bdrv_open_image()
   - Benoît: remove spurious new line removal
 - patch 2:
   - Benoît: document reference parameter of bdrv_open()
 - patch 3:
   - add the same assertions before every bdrv_file_open() translated to
     bdrv_open() and try not to initialize BDS pointers to NULL but
     rather set them right in front of bdrv_open() as in v2 for patch 1
   - remove addition of *pbs = NULL in bdrv_open_image() in front of the
     bdrv_file_open() being translated to bdrv_open()
 - patch 7:
   - Kevin: remove wrongly added
     "else if (drv->bdrv_needs_filename && !filename)" block
 - patch 8:
   - since patch 3 now does not add the *pbs = NULL anymore, this patch
     does not need to remove it either (I added the Reviewed-bys anyway,
     since this is just about temporary code introduced by this series)

v2:
 - patch 1:
   - added appropriate assertions before every bdrv_open() and
     bdrv_open_image() call where the BDS should be NULL (i.e., where a
     new BDS should be created) and it is not obvious
   - don't initialize BDS pointers to NULL if that is necessary for a
     bdrv_open(); rather, set them to NULL directly before calling
     bdrv_open() in order to make the expected behavior of bdrv_open()
     (create a new BDS) more obvious
   - make bdrv_open_image() behave the same way as bdrv_open() in regard
     to BDS creation/reuse (completed in patch 8)
   - keep "options == NULL" check in bdrv_open() together with the block
     for setting "bs->options"
 - patch 2:
   - due to options now possibly being NULL in the reference handling
     block of bdrv_open(), the condition for "options_non_empty" has to
     be adjusted
   - contextual changes due to patch 1
 - patch 3:
   - adjust comment for BDRV_O_PROTOCOL
   - contextual changes due to the previous patches
 - patch 4 (previously 5):
   - contextual changes due to the previous patches
 - patch 5 (previously 6):
   - bdrv_close() is unnecessary if the BDS could not be opened
 - patch 6:
   - melded together from previous patches 4, 7 and 8
 - patch 7 (previously 9):
   - make the "options" parameter of bdrv_file_open() an indirect
     pointer; if bdrv_file_open() takes the reference, it will be set to
     NULL; otherwise, the caller is responsible for freeing the QDict
 - patch 8 (previously 10):
   - make bdrv_open_image() behave the same way as bdrv_open() in regard
     to BDS creation/reuse
   - contextual changes due to the previous patches


Max Reitz (8):
  block: Change BDS parameter of bdrv_open() to **
  block: Add reference parameter to bdrv_open()
  block: Make bdrv_file_open() static
  block: Reuse reference handling from bdrv_open()
  block: Remove bdrv_new() from bdrv_file_open()
  block: Handle bs->options in bdrv_open() only
  block: Reuse success path from bdrv_open()
  block: Remove bdrv_open_image()'s force_raw option

 block.c               | 226 +++++++++++++++++++++++++-------------------------
 block/blkdebug.c      |   3 +-
 block/blkverify.c     |   6 +-
 block/cow.c           |   5 +-
 block/qcow.c          |   5 +-
 block/qcow2.c         |  18 ++--
 block/qed.c           |   8 +-
 block/sheepdog.c      |   7 +-
 block/vhdx.c          |   4 +-
 block/vmdk.c          |  19 +++--
 block/vvfat.c         |   6 +-
 blockdev.c            |  22 +++--
 hw/block/xen_disk.c   |   4 +-
 include/block/block.h |  13 +--
 qemu-img.c            |  12 ++-
 qemu-io.c             |   8 +-
 qemu-nbd.c            |   2 +-
 17 files changed, 197 insertions(+), 171 deletions(-)

-- 
1.8.5.4