[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <cover.1688393619.git.nabijaczleweli@nabijaczleweli.xyz>
Date: Mon, 3 Jul 2023 16:42:05 +0200
From: Ahelenia Ziemiańska
<nabijaczleweli@...ijaczleweli.xyz>
To: Christian Brauner <brauner@...nel.org>
Cc: Alexander Viro <viro@...iv.linux.org.uk>, Jan Kara <jack@...e.cz>,
Amir Goldstein <amir73il@...il.com>,
Chung-Chiang Cheng <cccheng@...ology.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v5 0/3] fanotify accounting for fs/splice.c
Previously: https://lore.kernel.org/linux-fsdevel/jbyihkyk5dtaohdwjyivambb2gffyjs3dodpofafnkkunxq7bu@jngkdxx65pux/t/#u
In short:
* most read/write APIs generate ACCESS/MODIFY for the read/written file(s)
* except the [vm]splice/tee family
(actually, since 6.4, splice itself /does/ generate events but only
for the non-pipes being spliced from/to; this commit is Fixes:ed)
* userspace that registers (i|fa)notify on pipes usually relies on it
actually working (coreutils tail -f is the primo example)
* it's sub-optimal when someone with a magic syscall can fill up a
pipe simultaneously ensuring it will never get serviced
Thus: actually generate ACCESS/MODIFY for all the
[vm]spliced/teed-from/to files.
LTP tests are staged in
https://git.sr.ht/~nabijaczleweli/ltp/commit/v4
("inotify13: new test for fs/splice.c functions vs pipes vs inotify"),
validating that one A and/or one M event per [vm]splice(), tee(),
and sendfile() is generated ‒
without this patchset, this only holds for sendfile().
Amir has identified a potential performance impact caused by
correctly generating events, and has prepared patches at
https://github.com/amir73il/linux/commits/fsnotify_pipe
that optimise the most common cases more aggressively.
Please review, and please consider taking these through the vfs
tree for 6.6.
Thanks,
Ahelenia Ziemiańska (3):
splice: always fsnotify_access(in), fsnotify_modify(out) on success
splice: fsnotify_access(fd)/fsnotify_modify(fd) in vmsplice
splice: fsnotify_access(in), fsnotify_modify(out) on success in tee
fs/splice.c | 43 +++++++++++++++++++++++++------------------
1 file changed, 25 insertions(+), 18 deletions(-)
--
2.39.2
Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)
Powered by blists - more mailing lists