[GIT PULL] 9p updates for 5.1

[GIT PULL] 9p updates for 5.1

[Dominique Martinet]

Hi Linus,

Here is a 9p update for 5.1; there honestly hasn't been much.

The memory leak fix has been commited rather recently because it was
sent fairly late, but it's simple enough that four days in -next should
be enough (that's why I waited till the last minute to send, sorry for
that - feel free to pick for rc2 if that makes a difference)


The following changes since commit 49a57857aeea06ca831043acbb0fa5e0f50602fd:

  Linux 5.0-rc3 (2019-01-21 13:14:44 +1300)

are available in the Git repository at:

  git://github.com/martinetd/linux tags/9p-for-5.1

for you to fetch changes up to bb06c388fa20ae24cfe80c52488de718a7e3a53f:

  9p/net: fix memory leak in p9_client_create (2019-03-13 11:50:04
  +0100)

----------------------------------------------------------------
Pull request for inlusion in 5.1

Two fixes (leak on invalid mount argument and possible deadlock on
i_size update on 32bit smp) and a fall-through warning cleanup

----------------------------------------------------------------
Gustavo A. R. Silva (1):
      9p: mark expected switch fall-through

Hou Tao (1):
      9p: use inode->i_lock to protect i_size_write() under 32-bit

zhengbin (1):
      9p/net: fix memory leak in p9_client_create

 fs/9p/v9fs_vfs.h       | 23 +++++++++++++++++++++--
 fs/9p/vfs_file.c       |  6 +++++-
 fs/9p/vfs_inode.c      | 23 +++++++++++------------
 fs/9p/vfs_inode_dotl.c | 27 ++++++++++++++-------------
 fs/9p/vfs_super.c      |  4 ++--
 net/9p/client.c        |  2 +-
 net/9p/trans_xen.c     |  2 +-
 7 files changed, 55 insertions(+), 32 deletions(-)

Re: [GIT PULL] 9p updates for 5.1

[Linus Torvalds]

On Sun, Mar 17, 2019 at 7:25 AM Dominique Martinet
<asmadeus@codewreck.org> wrote:
>
> Two fixes (leak on invalid mount argument and possible deadlock on
> i_size update on 32bit smp) and a fall-through warning cleanup

Hmm. I wonder what makes it valid to have concurrent updates to
i_size? Yes, yes, you added that spinlock to make the update itself
atomic on 32-bit, but it sounds a bit odd in the first place to have
two things possibly changing the size of a file at the same time...

Anyway, pulled, but just surprised...

            Linus

Re: [GIT PULL] 9p updates for 5.1

[pr-tracker-bot]

The pull request you sent on Sun, 17 Mar 2019 15:25:24 +0100:

> git://github.com/martinetd/linux tags/9p-for-5.1

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/db77bef53ba6ba5205ac1788bb8b66ce141ab020

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.wiki.kernel.org/userdoc/prtracker

Re: [GIT PULL] 9p updates for 5.1

[Dominique Martinet]

Linus Torvalds wrote on Sun, Mar 17, 2019:
> Hmm. I wonder what makes it valid to have concurrent updates to
> i_size? Yes, yes, you added that spinlock to make the update itself
> atomic on 32-bit, but it sounds a bit odd in the first place to have
> two things possibly changing the size of a file at the same time...

If the inode attributes are currently invalid (for example after
v9fs_invalidate_inode_attr()) then two concurrent user getattr requests
for the same inode will send two network requests which can both update
the i_size.

With cache=fscache or loose a write could also be concurrent with such
an update.


I plan on improving the first case with some "being revalidated" logic
now this pattern got reported but I don't think the second one can be
avoided, so that fix is still necessary in the long run afaict.


Thanks,
-- 
Dominique