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| author | Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz> | 2023-07-03 16:42:13 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-07-10 14:36:11 +0200 |
| commit | 12ee4b66af34f8e72f3b2fd93a946a955efe7c86 (patch) | |
| tree | fe5437f82cb470dce488406fa0b349185f84549a /fs/splice.c | |
| parent | ba38980add7ffc9e674ada5b4ded4e7d14e76581 (diff) | |
| download | linux-12ee4b66af34f8e72f3b2fd93a946a955efe7c86.tar.gz | |
splice: always fsnotify_access(in), fsnotify_modify(out) on success
The current behaviour caused an asymmetry where some write APIs
(write, sendfile) would notify the written-to/read-from objects,
but splice wouldn't.
This affected userspace which uses inotify, most notably coreutils
tail -f, to monitor pipes.
If the pipe buffer had been filled by a splice-family function:
* tail wouldn't know and thus wouldn't service the pipe, and
* all writes to the pipe would block because it's full,
thus service was denied.
(For the particular case of tail -f this could be worked around
with ---disable-inotify.)
Fixes: 983652c69199 ("splice: report related fsnotify events")
Link: https://lore.kernel.org/linux-fsdevel/jbyihkyk5dtaohdwjyivambb2gffyjs3dodpofafnkkunxq7bu@jngkdxx65pux/t/#u
Link: https://bugs.debian.org/1039488
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Acked-by: Jan Kara <jack@suse.cz>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Message-Id: <604ec704d933e0e0121d9e107ce914512e045fad.1688393619.git.nabijaczleweli@nabijaczleweli.xyz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/splice.c')
| -rw-r--r-- | fs/splice.c | 32 |
1 files changed, 15 insertions, 17 deletions
diff --git a/fs/splice.c b/fs/splice.c index 004eb1c4ce318..016b0a83df44c 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -1267,10 +1267,8 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, if ((in->f_flags | out->f_flags) & O_NONBLOCK) flags |= SPLICE_F_NONBLOCK; - return splice_pipe_to_pipe(ipipe, opipe, len, flags); - } - - if (ipipe) { + ret = splice_pipe_to_pipe(ipipe, opipe, len, flags); + } else if (ipipe) { if (off_in) return -ESPIPE; if (off_out) { @@ -1295,18 +1293,11 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, ret = do_splice_from(ipipe, out, &offset, len, flags); file_end_write(out); - if (ret > 0) - fsnotify_modify(out); - if (!off_out) out->f_pos = offset; else *off_out = offset; - - return ret; - } - - if (opipe) { + } else if (opipe) { if (off_out) return -ESPIPE; if (off_in) { @@ -1322,18 +1313,25 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out, ret = splice_file_to_pipe(in, opipe, &offset, len, flags); - if (ret > 0) - fsnotify_access(in); - if (!off_in) in->f_pos = offset; else *off_in = offset; + } else { + ret = -EINVAL; + } - return ret; + if (ret > 0) { + /* + * Generate modify out before access in: + * do_splice_from() may've already sent modify out, + * and this ensures the events get merged. + */ + fsnotify_modify(out); + fsnotify_access(in); } - return -EINVAL; + return ret; } static long __do_splice(struct file *in, loff_t __user *off_in, |