From: "Ahelenia Ziemiańska" <nabijaczleweli@nabijaczleweli.xyz>
To: Christian Brauner <brauner@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
Amir Goldstein <amir73il@gmail.com>,
Chung-Chiang Cheng <cccheng@synology.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v5 0/3] fanotify accounting for fs/splice.c
Date: Mon, 3 Jul 2023 16:42:05 +0200 [thread overview]
Message-ID: <cover.1688393619.git.nabijaczleweli@nabijaczleweli.xyz> (raw)
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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
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next reply other threads:[~2023-07-03 14:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 14:42 Ahelenia Ziemiańska [this message]
2023-07-03 14:42 ` [PATCH v5 1/3] splice: always fsnotify_access(in), fsnotify_modify(out) on success Ahelenia Ziemiańska
2023-07-03 15:02 ` Amir Goldstein
2023-07-03 14:42 ` [PATCH v5 2/3] splice: fsnotify_access(fd)/fsnotify_modify(fd) in vmsplice Ahelenia Ziemiańska
2023-07-03 14:42 ` [PATCH v5 3/3] splice: fsnotify_access(in), fsnotify_modify(out) on success in tee Ahelenia Ziemiańska
2023-07-03 15:44 ` [PATCH v5 0/3] fanotify accounting for fs/splice.c Christian Brauner
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