[PATCH v2 0/4] protect relocation with sb_start_write

[Naohiro Aota <naohiro.aota@wdc.com>]

This series is a follow-up to the series below. The old series added
an assertion to btrfs_relocate_chunk() to check if it is protected
with sb_start_write(). However, it revealed another location we need
to add sb_start_write() [1].

https://lore.kernel.org/linux-btrfs/cover.1645157220.git.naohiro.aota@wdc.com/T/

[1] https://lore.kernel.org/linux-btrfs/cover.1645157220.git.naohiro.aota@wdc.com/T/#e06eecc07ce1cd1e45bfd30a374bd2d15b4fd76d8

Patches 1 and 2 add (indirectly) sb_{start,end}_write() to the resumed
async balancing and device addition.

Patches 3 and 4 add an ASSERT to catch a future error.

--
v2:
  - Use mnt_want_write_file() instead of sb_start_write() for
    btrfs_ioctl_add_dev()
  - Drop bogus fixes tag
  - Change the stable target to meaningful 4.9+

Naohiro Aota (4):
  btrfs: mark resumed async balance as writing
  btrfs: mark device addition as mnt_want_write_file
  fs: add check functions for sb_start_{write,pagefault,intwrite}
  btrfs: assert that relocation is protected with sb_start_write()

 fs/btrfs/ioctl.c   | 11 +++++++++--
 fs/btrfs/volumes.c |  5 +++++
 include/linux/fs.h | 20 ++++++++++++++++++++
 3 files changed, 34 insertions(+), 2 deletions(-)

-- 
2.35.1