From: Connor Kuehl <ckuehl@redhat.com>
To: Max Reitz <mreitz@redhat.com>,
qemu-devel@nongnu.org, virtio-fs@redhat.com
Subject: Re: [Virtio-fs] [PATCH 0/9] virtiofsd: Allow using file handles instead of O_PATH FDs
Date: Fri, 4 Jun 2021 16:17:49 -0500 [thread overview]
Message-ID: <1ee5dea9-64d9-dc33-bc29-9caea1d59f07@redhat.com> (raw)
In-Reply-To: <20210604161337.16048-1-mreitz@redhat.com>
On 6/4/21 11:13 AM, Max Reitz wrote:
> Hi,
>
> This is the C virtiofsd equivalent to
> https://gitlab.com/virtio-fs/virtiofsd-rs/-/merge_requests/26. As such,
> the summary is pretty much the same:
>
> Storing an O_PATH file descriptor in every lo_inode object means we have
> a lot of FDs open, which is sometimes bad. This series adds an option
> (-o inode_file_handles) that will make virtiofsd attempt to generate a
> file handle for new inodes and store that instead of an FD. When an FD
> is needed for a given inode, we open the handle.
>
> To accomplish this, lo_inode.fd is should not be accessed directly
> anymore, but only through helper functions (mainly lo_inode_fd() and
> lo_inode_open()). A TempFd object is added to hide the difference
> between FDs that are bound to the lo_inode object (and so need not be
> closed after use) and temporary FDs from open_by_handle_at() (which do
> need to be closed after use).
>
> To prevent the problem I spent a long time talking about (if we don’t
> have an FD open for every inode, the inode can be deleted, its ID
> reused, and then the lookup in lo_data.inodes will find the old deleted
> inode), patch 7 adds a second hash table lo_data.inodes_by_handle that
> maps file handles to lo_inode objects. (Because file handles include a
> generation ID, so we can discern between the old and the new inode.)
>
> Patch 9 is completely optional, but I just really felt compelled to
> write it.
>
>
> Max Reitz (9):
> virtiofsd: Add TempFd structure
> virtiofsd: Use lo_inode_open() instead of openat()
> virtiofsd: Add lo_inode_fd() helper
> virtiofsd: Let lo_fd() return a TempFd
> virtiofsd: Let lo_inode_open() return a TempFd
> virtiofsd: Add lo_inode.fhandle
> virtiofsd: Add inodes_by_handle hash table
> virtiofsd: Optionally fill lo_inode.fhandle
> virtiofsd: Add lazy lo_do_find()
>
> tools/virtiofsd/helper.c | 3 +
> tools/virtiofsd/passthrough_ll.c | 809 +++++++++++++++++++++-----
> tools/virtiofsd/passthrough_seccomp.c | 2 +
> 3 files changed, 667 insertions(+), 147 deletions(-)
>
For the series:
Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
prev parent reply other threads:[~2021-06-04 21:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-04 16:13 [PATCH 0/9] virtiofsd: Allow using file handles instead of O_PATH FDs Max Reitz
2021-06-04 16:13 ` [PATCH 1/9] virtiofsd: Add TempFd structure Max Reitz
2021-06-04 16:13 ` [PATCH 2/9] virtiofsd: Use lo_inode_open() instead of openat() Max Reitz
2021-06-04 16:13 ` [PATCH 3/9] virtiofsd: Add lo_inode_fd() helper Max Reitz
2021-06-04 16:13 ` [PATCH 4/9] virtiofsd: Let lo_fd() return a TempFd Max Reitz
2021-06-04 16:13 ` [PATCH 5/9] virtiofsd: Let lo_inode_open() " Max Reitz
2021-06-04 16:13 ` [PATCH 6/9] virtiofsd: Add lo_inode.fhandle Max Reitz
2021-06-04 16:13 ` [PATCH 7/9] virtiofsd: Add inodes_by_handle hash table Max Reitz
2021-06-04 16:13 ` [PATCH 8/9] virtiofsd: Optionally fill lo_inode.fhandle Max Reitz
2021-06-08 10:43 ` Dr. David Alan Gilbert
2021-06-08 11:05 ` Max Reitz
2021-06-04 16:13 ` [PATCH 9/9] virtiofsd: Add lazy lo_do_find() Max Reitz
2021-06-04 21:17 ` Connor Kuehl [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1ee5dea9-64d9-dc33-bc29-9caea1d59f07@redhat.com \
--to=ckuehl@redhat.com \
--cc=mreitz@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=virtio-fs@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).