From: Matthew Wilcox <matthew-Ztpu424NOJ8@public.gmane.org>
To: Andrea Righi <andrea-oIIqvOZpAevzfdHfmsDf5w@public.gmane.org>
Cc: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Dave Chinner <david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org>,
Mike Frysinger <vapier-aBrp7R+bbdUdnm+yROfE0A@public.gmane.org>,
Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH v2] fadvise: introduce POSIX_FADV_DONTNEED_FS
Date: Wed, 27 Apr 2011 12:33:08 -0600 [thread overview]
Message-ID: <20110427183308.GA16716@parisc-linux.org> (raw)
In-Reply-To: <1303928027-5100-1-git-send-email-andrea-oIIqvOZpAevzfdHfmsDf5w@public.gmane.org>
On Wed, Apr 27, 2011 at 08:13:47PM +0200, Andrea Righi wrote:
> @@ -127,6 +128,12 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
> invalidate_mapping_pages(mapping, start_index,
> end_index);
> break;
> + case POSIX_FADV_DONTNEED_FS:
> + if (capable(CAP_SYS_ADMIN))
> + drop_pagecache_sb(file->f_dentry->d_sb, NULL);
> + else
> + ret = -EPERM;
> + break;
> default:
> ret = -EINVAL;
> }
Mmm ... what if I open /dev/sdxyz and call fadvise() on it? I think
you end up flushing /dev's page cache entries, instead of the filesystem
which is on /dev/sdxyz.
If I understand correctly, you want mapping->host->i_sb instead of
file->f_dentry->d_sb.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Wilcox <matthew@wil.cx>
To: Andrea Righi <andrea@betterlinux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Dave Chinner <david@fromorbit.com>,
Mike Frysinger <vapier@gentoo.org>,
Al Viro <viro@zeniv.linux.org.uk>, Arnd Bergmann <arnd@arndb.de>,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] fadvise: introduce POSIX_FADV_DONTNEED_FS
Date: Wed, 27 Apr 2011 12:33:08 -0600 [thread overview]
Message-ID: <20110427183308.GA16716@parisc-linux.org> (raw)
In-Reply-To: <1303928027-5100-1-git-send-email-andrea@betterlinux.com>
On Wed, Apr 27, 2011 at 08:13:47PM +0200, Andrea Righi wrote:
> @@ -127,6 +128,12 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice)
> invalidate_mapping_pages(mapping, start_index,
> end_index);
> break;
> + case POSIX_FADV_DONTNEED_FS:
> + if (capable(CAP_SYS_ADMIN))
> + drop_pagecache_sb(file->f_dentry->d_sb, NULL);
> + else
> + ret = -EPERM;
> + break;
> default:
> ret = -EINVAL;
> }
Mmm ... what if I open /dev/sdxyz and call fadvise() on it? I think
you end up flushing /dev's page cache entries, instead of the filesystem
which is on /dev/sdxyz.
If I understand correctly, you want mapping->host->i_sb instead of
file->f_dentry->d_sb.
--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2011-04-27 18:33 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-27 18:13 [PATCH v2] fadvise: introduce POSIX_FADV_DONTNEED_FS Andrea Righi
2011-04-27 18:13 ` Andrea Righi
[not found] ` <1303928027-5100-1-git-send-email-andrea-oIIqvOZpAevzfdHfmsDf5w@public.gmane.org>
2011-04-27 18:25 ` Mike Frysinger
2011-04-27 18:25 ` Mike Frysinger
2011-04-28 9:35 ` Andrea Righi
2011-04-27 18:33 ` Matthew Wilcox [this message]
2011-04-27 18:33 ` Matthew Wilcox
[not found] ` <20110427183308.GA16716-6jwH94ZQLHl74goWV3ctuw@public.gmane.org>
2011-04-27 18:39 ` Mike Frysinger
2011-04-27 18:39 ` Mike Frysinger
2011-04-27 18:47 ` Matthew Wilcox
[not found] ` <20110427184756.GB16716-6jwH94ZQLHl74goWV3ctuw@public.gmane.org>
2011-04-27 18:49 ` Mike Frysinger
2011-04-27 18:49 ` Mike Frysinger
2011-04-28 9:29 ` Andrea Righi
2011-05-04 21:44 ` Andrew Morton
2011-05-04 21:44 ` Andrew Morton
[not found] ` <20110504144411.7f32c00c.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2011-05-04 22:09 ` Andrea Righi
2011-05-04 22:09 ` Andrea Righi
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