[Qemu-devel] [PATCH v4 00/16] block: Remove "growable", add blk_new_open()

[Max Reitz]

This series removes the "growable" field from the BlockDriverState
object. Its use was to clamp guest requests against the limits of the
BDS; however, this can now be done more easily by moving those checks
into the BlockBackend functions.

In a future series, "growable" may be reintroduced (maybe with a
different name); it will then signify whether a BDS is able to grow (in
contrast to the current "growable", which signifies whether it is
allowed to). Maybe I will add it to the BlockDriver instead of the BDS,
though.

To be able to remove that field, qemu-io needs to be converted to
BlockBackend, which is done by this series as well. While working on
that I decided to convert blk_new_with_bs()+bdrv_open() to
blk_new_open(). I was skeptical about that decision at first, but it
seems good now that I was able to replace nearly every blk_new_with_bs()
call by blk_new_open(). In a future series I may try to convert some
remaining bdrv_open() calls to blk_new_open() as well. (And, in fact, in
a future series I *will* replace the last remaining blk_new_with_bs()
outside of blk_new_open() by blk_new_open().)

Finally, the question needs to be asked: If, after this series, every
BDS is allowed to grow, are there any users which do not use BB, but
should still be disallowed from reading/writing beyond a BDS's limits?
The only users I could see were the block jobs. Some of them should
indeed be converted to BB; but none of them takes a user-supplied offset
or size, all work on the full BDS (or only on parts which have been
modified, etc.). Therefore, it is by design impossible for them to
exceed the BDS's limits, which makes making all BDS's growable safe.


v4:
- Patch 1: Added blk_nb_sectors() [Eric]
- Patch 3: Added in order to get a more useful error message than just
  "Unknown protocol" [Eric]
- Patch 4: Added [Eric]
- Patch 5:
  - Use qdict_put() instead of qdict_put_obj() [Kevin]
  - Rebased onto the new patches 3 and 4
- Patch 6:
  - Note the fix for invalid drivers in the commit message; and note
    that the fix is not complete [Kevin]
  - Use qdict_put() instead of qdict_put_obj() [Kevin]
- Patch 7: Use qdict_put() instead of qdict_put_obj() [Kevin]
- Patch 8:
  - Do not skip output format validity test on unsafe [Kevin]
  - Dropped superfluous !unsafe in condition [Eric]
  - Use qdict_put() instead of qdict_put_obj() [Kevin]
- Patch 9: Use blk_nb_sectors() to replace bdrv_nb_sectors() (instead of
  blk_getlength() with a later division by BDRV_SECTOR_SIZE) [Eric]
- Patch 10: Use qdict_put() instead of qdict_put_obj() [Kevin]
- Patch 11: Dropped the hunk which removed the reset of qemuio_bs to
  NULL in close_f() [Kevin]
- Patch 12: Added a comment to the group file stating that 016 should
  not be reused [Eric/Kevin]
- Patch 13:
  - Use blk_nb_sectors() to replace bdrv_nb-sectors() [Eric]
  - Drop qemuio_bs [Kevin]
- Patch 15: Kept the "if (offset < 0)" check in
  bdrv_check_byte_request() [Kevin]

v3:
- Rebased (onto Stefan's branch rebased onto master)
- Fixed patch 4 [Stefano]

v2:
- Rebased [Kevin]
- Patch 2: Added a TODO comment about removing @filename and @flags from
  blk_new_open() when possible [Kevin]


git-backport-diff against v3:

Key:
[----] : patches are identical
[####] : number of functional differences between upstream/downstream patch
[down] : patch is downstream-only
The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively

001/16:[0006] [FC] 'block: Lift some BDS functions to the BlockBackend'
002/16:[----] [--] 'block: Add blk_new_open()'
003/16:[down] 'block: Add Error parameter to bdrv_find_protocol()'
004/16:[down] 'iotests: Add test for driver=qcow2,format=qcow2'
005/16:[0012] [FC] 'blockdev: Use blk_new_open() in blockdev_init()'
006/16:[0003] [FC] 'block/xen: Use blk_new_open() in blk_connect()'
007/16:[0002] [FC] 'qemu-img: Use blk_new_open() in img_open()'
008/16:[0016] [FC] 'qemu-img: Use blk_new_open() in img_rebase()'
009/16:[0030] [FC] 'qemu-img: Use BlockBackend as far as possible'
010/16:[0002] [FC] 'qemu-nbd: Use blk_new_open() in main()'
011/16:[0003] [FC] 'qemu-io: Use blk_new_open() in openfile()'
012/16:[0001] [FC] 'qemu-io: Remove "growable" option'
013/16:[0006] [FC] 'qemu-io: Use BlockBackend'
014/16:[----] [--] 'block: Clamp BlockBackend requests'
015/16:[0004] [FC] 'block: Remove "growable" from BDS'
016/16:[----] [--] 'block: Keep bdrv_check*_request()'s return value'



Max Reitz (16):
  block: Lift some BDS functions to the BlockBackend
  block: Add blk_new_open()
  block: Add Error parameter to bdrv_find_protocol()
  iotests: Add test for driver=qcow2,format=qcow2
  blockdev: Use blk_new_open() in blockdev_init()
  block/xen: Use blk_new_open() in blk_connect()
  qemu-img: Use blk_new_open() in img_open()
  qemu-img: Use blk_new_open() in img_rebase()
  qemu-img: Use BlockBackend as far as possible
  qemu-nbd: Use blk_new_open() in main()
  qemu-io: Use blk_new_open() in openfile()
  qemu-io: Remove "growable" option
  qemu-io: Use BlockBackend
  block: Clamp BlockBackend requests
  block: Remove "growable" from BDS
  block: Keep bdrv_check*_request()'s return value

 block.c                        |  73 +++++++------
 block/block-backend.c          | 224 ++++++++++++++++++++++++++++++++++++++
 block/qcow2.c                  |   6 --
 block/raw-posix.c              |   2 +-
 block/raw-win32.c              |   2 +-
 block/sheepdog.c               |   4 +-
 blockdev.c                     |  92 ++++++++--------
 hmp.c                          |   9 +-
 hw/block/xen_disk.c            |  27 ++---
 include/block/block.h          |   3 +-
 include/block/block_int.h      |   3 -
 include/qemu-io.h              |   4 +-
 include/sysemu/block-backend.h |  13 +++
 qemu-img.c                     | 158 +++++++++++++--------------
 qemu-io-cmds.c                 | 237 +++++++++++++++++++++--------------------
 qemu-io.c                      |  58 +++-------
 qemu-nbd.c                     |  25 ++---
 tests/qemu-iotests/016         |  73 -------------
 tests/qemu-iotests/016.out     |  23 ----
 tests/qemu-iotests/051         |   1 +
 tests/qemu-iotests/051.out     |  63 +++++------
 tests/qemu-iotests/087.out     |   8 +-
 tests/qemu-iotests/group       |   2 +-
 23 files changed, 603 insertions(+), 507 deletions(-)
 delete mode 100755 tests/qemu-iotests/016
 delete mode 100644 tests/qemu-iotests/016.out

-- 
2.1.0