[Qemu-devel] [PATCH V8 0/4] Refine and export backing file loop check

[Xu Wang]

If there is loop exists in the backing file chain, many problems
could be caused by it, such as no response and segment fault during
system boot. Hence stopping backing file loop appear is very necessary.
These patches refine and export loop checking function from collect_image_
info_list() to block.c and build a independent function named bdrv_
backing_file_loop_check(). Backing file loop checking is added before
image created, before change backing file and before system boot.

Updates from V7:
  1. Replace all error_report() in bdrv_backing_chain_okay() with error_setg().
  2. Fix error output in bdrv_img_create() when backing file doesn't exist.
  3. Add output in the bdrv_change_backing_file() (if not errp would has no
     way out).

Updates from V6:
  1. Combine bdrv_backing_chain_okay() and bdrv_new_chain_okay() into one.
  2. Delete bdrv_find_format() in the backing_chain_has_loop().
  3. Comments syntax and function naming updates.

Updates from V5:
  1. Simplify the function of loop checking (Just filename comparation.
     Thanks Eric's suggestion).
  2. Delete WIN32 platform support (There is no need to this patch now).
  3. Adjust position of backing file loop checking (calling checking function
     before change happen).
  4. Function name updates and comments description fix.

Updates from V4:
  1. Add backing file loop check in bdrv_new_open().
  2. Adjust open file logic of collect_image_info_list() (bdrv_new_open()
     is called only once when opening the whole chain).
  3. Remove redundant brackets in lnk file check logic.
  4. Add error output in bdrv_img_create().
  5. Remove MAX_PATH_LEN to use PATH_MAX instead.

Updates from V3:
  1. Comments fix for function bdrv_backing_file_loop_check().
  2. Add ret check for fseek()/fread() in get_lnk_target_file().
  3. Add limit of shortcuts filename length reading during comparing.
  4. Add error_report() in driv_init().
  5. Remove redundant loop check in qcow2/qed_change_backing_file().

Updates from V2:
  1. Removed parameter @chain from bdrv_backing_file_loop_check()
  2. Comments and format fix, all patches were checked by checkpatch.pl
  3. Fixed *bs leak.
  4. Improved logic of .lnk file recognization.
  5. Add filename lenth limit check in while()
  6. Changed get_win_inode() to get_inode() and move all inode get method
     into it to make logic more simpler.
  7. Added value of @fmt as suggested.
  8. Added backing file loop check in qcow2.c/qed.c


Xu Wang (4):
  block/qemu-img: Refine and export infinite loop checking in
    collect_image_info_list()
  block: Add check infinite loop in bdrv_img_create()
  block: Add backing file loop check in change_backing_file()
  blockdev: Add infinite loop check in drive_init()

 block.c               | 93 ++++++++++++++++++++++++++++++++++++++++++++++++---
 blockdev.c            |  8 +++++
 include/block/block.h |  3 ++
 qemu-img.c            | 52 ++++++++++++++--------------
 4 files changed, 126 insertions(+), 30 deletions(-)

-- 
1.8.1.4