From: Felix Janda <felix.janda@posteo.de>
To: Christoph Hellwig <hch@infradead.org>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 2/6] libxfs/linux.c: Replace use of ustat by stat
Date: Wed, 13 Jan 2016 18:42:41 +0100 [thread overview]
Message-ID: <20160113174241.GC10942@nyan> (raw)
In-Reply-To: <20160113075501.GC21939@infradead.org>
Christoph Hellwig wrote:
> On Tue, Jan 12, 2016 at 08:59:45PM +0100, Felix Janda wrote:
> > ustat has been used to check whether a device file is mounted.
> > The function is deprecated and not supported by uclibc and musl.
> > Now do the check using the *mntent functions.
> >
> > Based on patch by Natanael Copa <ncopa@alpinelinux.org>.
> >
> > Signed-off-by: Felix Janda <felix.janda@posteo.de>
>
> ustat is a lot more efficient in checking for the mountedness
> than this loop, so I'd really prefer not to do this unconditionally.
Is this really performance relevant?
Notice that linux's platform_check_iswritable does something very
similar. I've tried to make it consistent with the version from
freebsd.c.
> As far as Linux is concerned the best thing we could do is to use
> O_EXCL for any open of a device file, as Linux overloadds O_EXCL
> behavior for block devices so that any other O_EXCL open will
> be rejected if one has the file open.
>
> But that might be a major pain to find into the cross platform
> framework..
Hmm, so we couldn't we use for linux just something like
int
platform_check_ismounted(char *name, char *block, struct stat64 *s, int verbose)
{
int fd = open(block, O_EXCL);
int e = errno;
if (fd != -1) close(fd);
if (e == EBUSY) {
if (verbose)
fprintf(stderr, _("%s: %s contains a mounted filesystem\n"), progname, name);
return 1;
}
return 0;
}
Felix
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next prev parent reply other threads:[~2016-01-13 17:45 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1452627740.git.felix.janda@posteo.de>
2016-01-12 19:59 ` [PATCH 1/6] Move from __uint*_t types to uint*_t and likewise for __int*_t Felix Janda
2016-01-12 21:24 ` Dave Chinner
2016-01-12 21:46 ` Felix Janda
2016-01-12 22:02 ` Dave Chinner
2016-01-13 7:48 ` Christoph Hellwig
2016-01-20 0:46 ` Dave Chinner
2016-01-12 19:59 ` [PATCH 2/6] libxfs/linux.c: Replace use of ustat by stat Felix Janda
2016-01-12 21:24 ` Dave Chinner
2016-01-12 21:33 ` Felix Janda
2016-01-13 7:55 ` Christoph Hellwig
2016-01-13 17:42 ` Felix Janda [this message]
2016-01-14 10:20 ` Christoph Hellwig
2016-01-14 19:07 ` Felix Janda
2016-06-18 14:53 ` Felix Janda
2016-06-22 12:59 ` Christoph Hellwig
2016-09-04 1:23 ` Eric Sandeen
2016-09-08 0:00 ` Dave Chinner
2016-01-12 19:59 ` [PATCH 3/6] fsr/xfs_fsr.c: Include <paths.h> for _PATH_MOUNTED Felix Janda
2016-01-13 7:55 ` Christoph Hellwig
2016-01-12 20:00 ` [PATCH 4/6] linux.h: Use off64_t instead of loff_t Felix Janda
2016-01-13 7:55 ` Christoph Hellwig
2016-01-12 20:00 ` [PATCH 5/6] include/linux.h: Include <stdio.h> for fprintf and stderr Felix Janda
2016-01-13 7:55 ` Christoph Hellwig
2016-01-12 20:00 ` [PATCH 6/6] Add configure check for members of dirent for use in io/readdir.c Felix Janda
2016-01-12 21:30 ` Dave Chinner
2016-01-12 21:37 ` Felix Janda
2016-01-12 22:37 ` Dave Chinner
2016-01-13 7:58 ` Christoph Hellwig
2016-01-13 17:09 ` Felix Janda
2016-01-14 10:17 ` Christoph Hellwig
2016-01-14 19:06 ` Felix Janda
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