Re: POSIX violation by writeback error

Adam Borowski
2018-09-25T17:35:24Z

On Tue, Sep 25, 2018 at 11:46:27AM -0400, Theodore Y. Ts'o wrote:
> P.S. One thought: it might be cool if there was some way for
> userspace applications to mark files with "nuke if not closed" flag,
> such that if the system crashes, the file systems would automatically
> unlink the file after a reboot or if the process was killed or exits
> without an explicit close(2). For networked/remote file systems that
> supported this flag, after the client comes back up after a reboot, it
> could notify the server that all files created previously from that
> client should be unlinked.
>
> Unlike O_TMPFILE, this would require file system changes to support,
> so maybe it's not worth having something which automatically cleans up
> files that were in the middle of being written at the time of a system
> crash.

Isn't this what the snippet for O_TMPFILE in "man 2 open" does?:

char path[PATH_MAX];
fd = open("/path/to/dir", O_TMPFILE | O_RDWR,
S_IRUSR | S_IWUSR);

/* File I/O on 'fd'... */

snprintf(path, PATH_MAX, "/proc/self/fd/%d", fd);
linkat(AT_FDCWD, path, AT_FDCWD, "/path/for/file",
AT_SYMLINK_FOLLOW);

Meow!
--
⢀⣴⠾⠻⢶⣦⠀ 10 people enter a bar:
⣾⠁⢰⠒⠀⣿⡁ • 1 who understands binary,
⢿⡄⠘⠷⠚⠋⠀ • 1 who doesn't,
⠈⠳⣄⠀⠀⠀⠀ • and E who prefer to write it as hex.