From: Jan Blunck <jblunck@suse.de>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
viro@zeniv.linux.org.uk, bharata@in.ibm.com, dwmw2@infradead.org,
mszeredi@suse.cz, vaurora@redhat.com
Subject: Re: [PATCH 00/32] VFS based Union Mount (V3)
Date: Tue, 19 May 2009 15:10:55 +0200 [thread overview]
Message-ID: <20090519131055.GQ16526@bolzano.suse.de> (raw)
In-Reply-To: <200905191421.21026.arnd@arndb.de>
On Tue, May 19, Arnd Bergmann wrote:
>
> So what would go wrong if you only made them persistent for writable file
> systems, but allowed fallthrough dentries to be discarded for read-only
> file systems? As long as the lower layers don't change, you should still
> be able to reconstruct the same dentries every time you do a readdir, right?
>
This can work if you do this when the last file descriptor on the directory is
closed. I have a similar patch around for tmpfs readdir (the SLES8 glibc is
seeking on readdir, so it broke some of our build servers that use tmpfs).
One idea would be to separate the "fallthru in tmpfs" handling into its own
library so that it can be shared by filesystems. This would become something
similar to the On-Disk-Format (ODF) approach that Erez Zadok followed with
UnionFS.
next prev parent reply other threads:[~2009-05-19 13:10 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-18 16:08 [PATCH 00/32] VFS based Union Mount (V3) Jan Blunck
2009-05-18 16:08 ` [PATCH 01/32] atomic: Only take lock when the counter drops to zero on UP as well Jan Blunck
2009-05-18 16:08 ` [PATCH 02/32] VFS: BUG() if somebody tries to rehash an already hashed dentry Jan Blunck
2009-05-18 16:08 ` [PATCH 03/32] VFS: propagate mnt_flags into do_loopback Jan Blunck
2009-05-18 16:09 ` [PATCH 04/32] VFS: Make lookup_hash() return a struct path Jan Blunck
2009-05-18 16:09 ` [PATCH 05/32] VFS: Remove unnecessary micro-optimization in cached_lookup() Jan Blunck
2009-05-18 16:09 ` [PATCH 06/32] VFS: Make real_lookup() return a struct path Jan Blunck
2009-05-18 16:09 ` [PATCH 07/32] VFS: Introduce dput() variant that maintains a kill-list Jan Blunck
2009-05-18 16:09 ` [PATCH 08/32] whiteout: Don't return information about whiteouts to userspace Jan Blunck
2009-05-18 16:09 ` [PATCH 09/32] whiteout: Add vfs_whiteout() and whiteout inode operation Jan Blunck
2009-05-18 16:09 ` [PATCH 10/32] whiteout: Set S_OPAQUE inode flag when creating directories Jan Blunck
2009-05-18 16:09 ` [PATCH 11/32] whiteout: Add whiteout support to tmpfs Jan Blunck
2009-05-18 16:09 ` [PATCH 12/32] whiteout: Split of ext2_append_link() from ext2_add_link() Jan Blunck
2009-05-18 16:09 ` [PATCH 13/32] whiteout: Add whiteout support to ext2 Jan Blunck
2009-05-18 16:09 ` [PATCH 14/32] whiteout: Add path_whiteout() helper Jan Blunck
2009-05-18 16:09 ` [PATCH 15/32] union-mount: Documentation Jan Blunck
2009-05-25 6:25 ` hooanon05
2009-05-25 8:03 ` Arnd Bergmann
2009-05-25 8:43 ` hooanon05
2009-06-18 19:05 ` Valerie Aurora
2009-06-19 1:53 ` hooanon05
2009-05-18 16:09 ` [PATCH 16/32] union-mount: Introduce MNT_UNION and MS_UNION flags Jan Blunck
2009-05-18 16:09 ` [PATCH 17/32] union-mount: Introduce union_mount structure Jan Blunck
2009-05-18 16:09 ` [PATCH 18/32] union-mount: Drive the union cache via dcache Jan Blunck
2009-05-18 16:09 ` [PATCH 19/32] union-mount: Some checks during namespace changes Jan Blunck
2009-05-18 16:09 ` [PATCH 20/32] union-mount: Changes to the namespace handling Jan Blunck
2009-05-18 16:09 ` [PATCH 21/32] union-mount: Make lookup work for union-mounted file systems Jan Blunck
2009-05-19 16:15 ` Miklos Szeredi
2009-05-19 17:30 ` Valerie Aurora
2009-05-20 10:21 ` Miklos Szeredi
2009-05-18 16:09 ` [PATCH 22/32] union-mount: stop lookup when directory has S_OPAQUE flag set Jan Blunck
2009-05-18 16:09 ` [PATCH 23/32] union-mount: stop lookup when finding a whiteout Jan Blunck
2009-05-18 16:09 ` [PATCH 24/32] union-mount: in-kernel file copy between union mounted filesystems Jan Blunck
2009-05-18 16:09 ` [PATCH 25/32] union-mount: check for logically empty directory (FIXME) Jan Blunck
2009-05-18 16:09 ` [PATCH 26/32] union-mount: call do_whiteout() on unlink and rmdir Jan Blunck
2009-05-18 16:09 ` [PATCH 27/32] union-mount: Always create topmost directory on open Jan Blunck
2009-05-18 16:09 ` [PATCH 28/32] union-mount: Basic fallthru definitions Jan Blunck
2009-05-18 16:09 ` [PATCH 29/32] union mount: Support for fallthru entries in union mount lookup Jan Blunck
2009-05-18 16:09 ` [PATCH 30/32] union mount: ext2 fallthru support Jan Blunck
2009-05-18 16:32 ` Andreas Dilger
2009-05-19 9:42 ` Jan Blunck
2009-05-19 14:05 ` Andreas Dilger
2009-05-19 16:13 ` Jan Blunck
2009-05-18 16:09 ` [PATCH 31/32] union-mount: tmpfs " Jan Blunck
2009-05-18 16:09 ` [PATCH 32/32] union-mount: Copy up directory entries on first readdir() Jan Blunck
2009-05-18 20:40 ` [PATCH] Userland for VFS based Union Mount (V3) Valerie Aurora
2009-05-21 13:53 ` Andreas Dilger
2009-06-18 3:22 ` Valerie Aurora
2009-05-19 9:48 ` [PATCH 00/32] " Miklos Szeredi
2009-05-19 10:29 ` Jan Blunck
2009-05-19 10:35 ` Miklos Szeredi
2009-05-19 10:39 ` Jan Blunck
2009-05-19 11:54 ` Arnd Bergmann
2009-05-19 12:15 ` Jan Blunck
2009-05-19 12:21 ` Arnd Bergmann
2009-05-19 13:10 ` Jan Blunck [this message]
2009-05-19 17:23 ` Valerie Aurora
2009-05-20 9:05 ` Miklos Szeredi
2009-06-08 19:44 ` Valerie Aurora
2009-06-16 15:19 ` Miklos Szeredi
2009-05-21 12:54 ` Jan Rekorajski
2009-06-08 19:57 ` Valerie Aurora
2009-06-08 22:44 ` Jan Rekorajski
2009-06-08 22:48 ` Valerie Aurora
2009-06-15 9:55 ` Jan Rekorajski
2009-06-18 3:23 ` Valerie Aurora
2009-06-04 11:38 ` Scott James Remnant
2009-06-09 22:15 ` Valerie Aurora
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