From: Miklos Szeredi <miklos@szeredi.hu>
To: jblunck@suse.de
Cc: 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 21/32] union-mount: Make lookup work for union-mounted file systems
Date: Tue, 19 May 2009 18:15:52 +0200 [thread overview]
Message-ID: <E1M6Ryq-0001RP-Oe@pomaz-ex.szeredi.hu> (raw)
In-Reply-To: <1242662968-11684-22-git-send-email-jblunck@suse.de> (message from Jan Blunck on Mon, 18 May 2009 18:09:17 +0200)
On Mon, 18 May 2009, Jan Blunck wrote:
> On union-mounted file systems the lookup function must also visit lower layers
> of the union-stack when doing a lookup. This patches add support for
> union-mounts to cached lookups and real lookups.
>
> We have 3 different styles of lookup functions now:
> - multiple pathname components, follow mounts, follow union, follow symlinks
> - single pathname component, doesn't follow mounts, follow union, doesn't
> follow symlinks
> - single pathname component doesn't follow mounts, doesn't follow unions,
> doesn't follow symlinks
Ugh... I do wonder if this could be done in a less complicated way,
there does seem to be a fair amount of duplication between these
functions.
Worse, it looks like there are still i_mutex lock ordering issues
(__hash_lookup_topmost()/__hash_lookup_build_union()). What happens
if two separate unions of two filesystems are built where the order of
branches is reversed?
Thanks,
Miklos
next prev parent reply other threads:[~2009-05-19 16:16 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 [this message]
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
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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