From: Valerie Aurora <vaurora@redhat.com>
To: hooanon05@yahoo.co.jp
Cc: Arnd Bergmann <arnd@arndb.de>, Jan Blunck <jblunck@suse.de>,
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
Subject: Re: [PATCH 15/32] union-mount: Documentation
Date: Thu, 18 Jun 2009 15:05:59 -0400 [thread overview]
Message-ID: <20090618190558.GB22206@shell> (raw)
In-Reply-To: <7294.1243240990@jrobl>
On Mon, May 25, 2009 at 05:43:10PM +0900, hooanon05@yahoo.co.jp wrote:
>
> Arnd Bergmann:
> > Right, but that is consistent with how the kernel would treat a
> > rename from one mount point to another, and tools like 'mv'
> > can handle this in user space.
>
> Yes, that is the description in the union mount document.
> While it says to rename a regular file is implemented, the code differs
> actually.
> ----------------------------------------
> +Rename across different levels of the union is implemented as a copy-up
> +operation for regular files. Rename of directories simply returns EXDEV, the
> +same as if we tried to rename across different mounts. Most applications have
> :::
> ----------------------------------------
Ah, we did implement that in an earlier version. I don't know if we
dropped the patch by accident or on purpose, but the original version
is below. We will either put this feature back or fix the
documentation. Thanks!
-VAL
Subject: union-mount: copyup on rename
Add copyup renaming of regular files on union mounts. Directories are still
lazyly copied with the help of user-space.
Signed-off-by: Jan Blunck <jblunck@suse.de>
---
fs/namei.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 124 insertions(+), 7 deletions(-)
Index: b/fs/namei.c
===================================================================
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1532,6 +1532,8 @@ static int do_path_lookup(int dfd, const
nd->path = fs->pwd;
path_get(&fs->pwd);
read_unlock(&fs->lock);
+ /* Force a union_relookup() */
+ nd->um_flags = LAST_LOWLEVEL;
} else {
struct dentry *dentry;
@@ -3684,6 +3686,97 @@ int vfs_rename(struct inode *old_dir, st
return error;
}
+int vfs_rename_union(struct nameidata *oldnd, struct path *old,
+ struct nameidata *newnd, struct path *new)
+{
+ struct inode *old_dir = oldnd->path.dentry->d_inode;
+ struct inode *new_dir = newnd->path.dentry->d_inode;
+ struct qstr old_name;
+ char *name;
+ struct dentry *dentry;
+ int error;
+
+ if (old->dentry->d_inode == new->dentry->d_inode)
+ return 0;
+
+ error = may_whiteout(old->dentry, 0);
+ if (error)
+ return error;
+ if (!old_dir->i_op || !old_dir->i_op->whiteout)
+ return -EPERM;
+
+ if (!new->dentry->d_inode)
+ error = may_create(new_dir, new->dentry, NULL);
+ else
+ error = may_delete(new_dir, new->dentry, 0);
+ if (error)
+ return error;
+
+ DQUOT_INIT(old_dir);
+ DQUOT_INIT(new_dir);
+
+ error = security_inode_rename(old_dir, old->dentry,
+ new_dir, new->dentry);
+ if (error)
+ return error;
+
+ error = -EBUSY;
+ if (d_mountpoint(old->dentry) || d_mountpoint(new->dentry))
+ return error;
+
+ error = -ENOMEM;
+ name = kmalloc(old->dentry->d_name.len, GFP_KERNEL);
+ if (!name)
+ return error;
+ strncpy(name, old->dentry->d_name.name, old->dentry->d_name.len);
+ name[old->dentry->d_name.len] = 0;
+ old_name.len = old->dentry->d_name.len;
+ old_name.hash = old->dentry->d_name.hash;
+ old_name.name = name;
+
+ /* possibly delete the existing new file */
+ if ((newnd->path.dentry == new->dentry->d_parent) && new->dentry->d_inode) {
+ /* FIXME: inode may be truncated while we hold a lock */
+ error = vfs_unlink(new_dir, new->dentry);
+ if (error)
+ goto freename;
+
+ dentry = __lookup_hash(&new->dentry->d_name,
+ newnd->path.dentry, newnd);
+ if (IS_ERR(dentry))
+ goto freename;
+
+ dput(new->dentry);
+ new->dentry = dentry;
+ }
+
+ /* copyup to the new file */
+ error = __union_copyup(old, newnd, new);
+ if (error)
+ goto freename;
+
+ /* whiteout the old file */
+ dentry = __lookup_hash(&old_name, oldnd->path.dentry, oldnd);
+ error = PTR_ERR(dentry);
+ if (IS_ERR(dentry))
+ goto freename;
+ error = vfs_whiteout(old_dir, dentry);
+ dput(dentry);
+
+ /* FIXME: This is acutally unlink() && create() ... */
+/*
+ if (!error) {
+ const char *new_name = old_dentry->d_name.name;
+ fsnotify_move(old_dir, new_dir, old_name.name, new_name, 0,
+ new_dentry->d_inode, old_dentry->d_inode);
+ }
+*/
+freename:
+ kfree(old_name.name);
+ return error;
+}
+
+
static int do_rename(int olddfd, const char *oldname,
int newdfd, const char *newname)
{
@@ -3701,10 +3794,7 @@ static int do_rename(int olddfd, const c
if (error)
goto exit1;
- error = -EXDEV;
- if (oldnd.path.mnt != newnd.path.mnt)
- goto exit2;
-
+lock:
old_dir = oldnd.path.dentry;
error = -EBUSY;
if (oldnd.last_type != LAST_NORM)
@@ -3742,12 +3832,39 @@ static int do_rename(int olddfd, const c
error = -ENOTEMPTY;
if (new.dentry == trap)
goto exit5;
- /* renaming on unions is done by the user-space */
+ /* renaming of directories on unions is done by the user-space */
+ error = -EXDEV;
+ if (is_unionized(oldnd.path.dentry, oldnd.path.mnt) &&
+ S_ISDIR(old.dentry->d_inode->i_mode))
+ goto exit5;
+ /* renameing of other files on unions is done by copyup */
+ if ((is_unionized(oldnd.path.dentry, oldnd.path.mnt) &&
+ (oldnd.um_flags & LAST_LOWLEVEL)) ||
+ (is_unionized(newnd.path.dentry, newnd.path.mnt) &&
+ (newnd.um_flags & LAST_LOWLEVEL))) {
+ path_put_conditional(&new, &newnd);
+ path_put_conditional(&old, &oldnd);
+ unlock_rename(new_dir, old_dir);
+ error = union_relookup_topmost(&oldnd,
+ oldnd.flags & ~LOOKUP_PARENT);
+ if (error)
+ goto exit2;
+ error = union_relookup_topmost(&newnd,
+ newnd.flags & ~LOOKUP_PARENT);
+ if (error)
+ goto exit2;
+ goto lock;
+ }
+
error = -EXDEV;
- if (is_unionized(oldnd.path.dentry, oldnd.path.mnt))
+ if (oldnd.path.mnt != newnd.path.mnt)
goto exit5;
- if (is_unionized(newnd.path.dentry, newnd.path.mnt))
+
+ if (is_unionized(oldnd.path.dentry, oldnd.path.mnt) &&
+ (old.dentry->d_parent != oldnd.path.dentry)) {
+ error = vfs_rename_union(&oldnd, &old, &newnd, &new);
goto exit5;
+ }
error = mnt_want_write(oldnd.path.mnt);
if (error)
next prev parent reply other threads:[~2009-06-18 19:06 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 [this message]
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
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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