From: Valerie Aurora <vaurora@redhat.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Jan Blunck <jblunck@suse.de>, Valerie Aurora <vaurora@redhat.com>
Subject: [PATCH 07/35] whiteout: Allow removal of a directory with whiteouts
Date: Thu, 15 Apr 2010 16:04:14 -0700 [thread overview]
Message-ID: <1271372682-21225-8-git-send-email-vaurora@redhat.com> (raw)
In-Reply-To: <1271372682-21225-7-git-send-email-vaurora@redhat.com>
From: Jan Blunck <jblunck@suse.de>
do_whiteout() allows removal of a directory when it has whiteouts but
is logically empty.
XXX - This patch abuses readdir() to check if the union directory is
logically empty - that is, all the entries are whiteouts (or "." or
".."). Currently, we have no clean VFS interface to ask the lower
file system if a directory is empty.
Fixes:
- Add ->is_directory_empty() op
- Add is_directory_empty flag to dentry (ugly dcache populate)
- Ask underlying fs to remove it and look for an error return
- (your idea here)
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Valerie Aurora <vaurora@redhat.com>
---
fs/namei.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 956083a..991767b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2307,6 +2307,94 @@ int path_whiteout(struct path *dir_path, struct dentry *dentry, int isdir)
EXPORT_SYMBOL(path_whiteout);
/*
+ * XXX - We are abusing readdir to check if a union directory is
+ * logically empty.
+ */
+static int filldir_is_empty(void *__buf, const char *name, int namlen,
+ loff_t offset, u64 ino, unsigned int d_type)
+{
+ int *is_empty = (int *)__buf;
+
+ switch (namlen) {
+ case 2:
+ if (name[1] != '.')
+ break;
+ case 1:
+ if (name[0] != '.')
+ break;
+ return 0;
+ }
+
+ if (d_type == DT_WHT)
+ return 0;
+
+ (*is_empty) = 0;
+ return 0;
+}
+
+static int directory_is_empty(struct dentry *dentry, struct vfsmount *mnt)
+{
+ struct file *file;
+ int err;
+ int is_empty = 1;
+
+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
+
+ /* references for the file pointer */
+ dget(dentry);
+ mntget(mnt);
+
+ file = dentry_open(dentry, mnt, O_RDONLY, current_cred());
+ if (IS_ERR(file))
+ return 0;
+
+ err = vfs_readdir(file, filldir_is_empty, &is_empty);
+
+ fput(file);
+ return is_empty;
+}
+
+static int do_whiteout(struct nameidata *nd, struct path *path, int isdir)
+{
+ struct path safe = { .dentry = dget(nd->path.dentry),
+ .mnt = mntget(nd->path.mnt) };
+ struct dentry *dentry = path->dentry;
+ int err;
+
+ err = may_whiteout(nd->path.dentry->d_inode, dentry, isdir);
+ if (err)
+ goto out;
+
+ err = -ENOENT;
+ if (!dentry->d_inode)
+ goto out;
+
+ err = -ENOTEMPTY;
+ if (isdir && !directory_is_empty(path->dentry, path->mnt))
+ goto out;
+
+ if (nd->path.dentry != dentry->d_parent) {
+ dentry = __lookup_hash(&path->dentry->d_name, nd->path.dentry,
+ nd);
+ err = PTR_ERR(dentry);
+ if (IS_ERR(dentry))
+ goto out;
+
+ dput(path->dentry);
+ if (path->mnt != safe.mnt)
+ mntput(path->mnt);
+ path->mnt = nd->path.mnt;
+ path->dentry = dentry;
+ }
+
+ err = vfs_whiteout(nd->path.dentry->d_inode, dentry, isdir);
+
+out:
+ path_put(&safe);
+ return err;
+}
+
+/*
* We try to drop the dentry early: we should have
* a usage count of 2 if we're the only user of this
* dentry, and if that is true (possibly after pruning
--
1.6.3.3
next prev parent reply other threads:[~2010-04-15 23:06 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 23:04 [PATCH 00/35] Union mounts - everything but the xattrs Valerie Aurora
2010-04-15 23:04 ` [PATCH 01/35] VFS: Make lookup_hash() return a struct path Valerie Aurora
2010-04-15 23:04 ` [PATCH 02/35] VFS: Add read-only users count to superblock Valerie Aurora
[not found] ` <1271372682-21225-4-git-send-email-vaurora@redhat.com>
2010-04-15 23:04 ` [PATCH 04/35] whiteout/NFSD: Don't return information about whiteouts to userspace Valerie Aurora
2010-04-15 23:04 ` [PATCH 05/35] whiteout: Add vfs_whiteout() and whiteout inode operation Valerie Aurora
2010-04-15 23:04 ` [PATCH 06/35] whiteout: Set S_OPAQUE inode flag when creating directories Valerie Aurora
2010-04-15 23:04 ` Valerie Aurora [this message]
2010-04-15 23:04 ` [PATCH 08/35] whiteout: tmpfs whiteout support Valerie Aurora
2010-04-15 23:04 ` [PATCH 09/35] whiteout: Split of ext2_append_link() from ext2_add_link() Valerie Aurora
2010-04-15 23:04 ` [PATCH 10/35] whiteout: ext2 whiteout support Valerie Aurora
2010-04-15 23:04 ` [PATCH 11/35] whiteout: jffs2 " Valerie Aurora
2010-04-15 23:04 ` [PATCH 12/35] fallthru: Basic fallthru definitions Valerie Aurora
2010-04-15 23:04 ` [PATCH 13/35] fallthru: ext2 fallthru support Valerie Aurora
2010-04-15 23:04 ` [PATCH 14/35] fallthru: jffs2 " Valerie Aurora
2010-04-15 23:04 ` [PATCH 15/35] fallthru: tmpfs " Valerie Aurora
2010-04-15 23:04 ` [PATCH 16/35] union-mount: Writable overlays/union mounts documentation Valerie Aurora
2010-04-15 23:04 ` [PATCH 17/35] union-mount: Introduce MNT_UNION and MS_UNION flags Valerie Aurora
2010-04-15 23:04 ` [PATCH 18/35] union-mount: Introduce union_mount structure and basic operations Valerie Aurora
2010-04-15 23:04 ` [PATCH 19/35] union-mount: Drive the union cache via dcache Valerie Aurora
2010-04-15 23:04 ` [PATCH 20/35] union-mount: Implement union lookup Valerie Aurora
2010-04-15 23:04 ` [PATCH 21/35] union-mount: Support for mounting union mount file systems Valerie Aurora
2010-04-15 23:04 ` [PATCH 22/35] union-mount: Call do_whiteout() on unlink and rmdir in unions Valerie Aurora
2010-04-15 23:04 ` [PATCH 23/35] union-mount: Copy up directory entries on first readdir() Valerie Aurora
2010-04-15 23:04 ` [PATCH 24/35] VFS: Split inode_permission() and create path_permission() Valerie Aurora
2010-04-15 23:04 ` [PATCH 25/35] VFS: Create user_path_nd() to lookup both parent and target Valerie Aurora
2010-04-15 23:04 ` [PATCH 26/35] union-mount: In-kernel copyup routines Valerie Aurora
2010-04-15 23:04 ` [PATCH 27/35] union-mount: Implement union-aware access()/faccessat() Valerie Aurora
2010-04-15 23:04 ` [PATCH 28/35] union-mount: Implement union-aware link() Valerie Aurora
2010-04-15 23:04 ` [PATCH 29/35] union-mount: Implement union-aware rename() Valerie Aurora
2010-04-15 23:04 ` [PATCH 30/35] union-mount: Implement union-aware writable open() Valerie Aurora
2010-04-15 23:04 ` [PATCH 31/35] union-mount: Implement union-aware chown() Valerie Aurora
2010-04-15 23:04 ` [PATCH 32/35] union-mount: Implement union-aware truncate() Valerie Aurora
2010-04-15 23:04 ` [PATCH 33/35] union-mount: Implement union-aware chmod()/fchmodat() Valerie Aurora
2010-04-15 23:04 ` [PATCH 34/35] union-mount: Implement union-aware lchown() Valerie Aurora
2010-04-15 23:04 ` [PATCH 35/35] union-mount: Implement union-aware utimensat() Valerie Aurora
2010-04-20 16:30 ` [PATCH 16/35] union-mount: Writable overlays/union mounts documentation Miklos Szeredi
2010-04-28 20:19 ` Valerie Aurora
2010-04-29 9:33 ` Miklos Szeredi
2010-04-29 20:20 ` Valerie Aurora
2010-05-10 12:57 ` Miklos Szeredi
2010-05-17 19:55 ` Valerie Aurora
2010-04-29 16:10 ` J. R. Okajima
2010-04-19 12:40 ` [PATCH 13/35] fallthru: ext2 fallthru support Jan Blunck
2010-04-19 13:02 ` David Woodhouse
2010-04-19 13:23 ` Jan Blunck
2010-04-19 13:30 ` Jamie Lokier
2010-04-19 14:12 ` Jan Blunck
2010-04-19 14:23 ` Valerie Aurora
2010-04-19 14:53 ` Miklos Szeredi
2010-04-20 21:34 ` Jamie Lokier
2010-04-21 8:42 ` Jan Blunck
2010-04-21 9:22 ` Jamie Lokier
2010-04-21 9:34 ` Miklos Szeredi
2010-04-21 9:52 ` Jamie Lokier
2010-04-21 10:17 ` Miklos Szeredi
2010-04-21 17:36 ` Jamie Lokier
2010-04-21 21:34 ` Valerie Aurora
2010-04-21 21:38 ` Valerie Aurora
2010-04-21 22:10 ` Jamie Lokier
2010-04-22 10:30 ` J. R. Okajima
2010-04-20 21:40 ` Jamie Lokier
2010-04-19 13:03 ` [PATCH 11/35] whiteout: jffs2 whiteout support David Woodhouse
2010-04-19 14:26 ` Valerie Aurora
2010-04-16 15:59 ` [PATCH 04/35] whiteout/NFSD: Don't return information about whiteouts to userspace J. Bruce Fields
2010-04-19 12:37 ` Jan Blunck
2010-04-19 13:54 ` J. Bruce Fields
2010-04-15 23:45 ` [PATCH 03/35] autofs4: Save autofs trigger's vfsmount in super block info Valerie Aurora
2010-04-21 22:06 ` [PATCH 00/35] Union mounts - everything but the xattrs Randy Dunlap
2010-04-21 23:35 ` Valerie Aurora
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1271372682-21225-8-git-send-email-vaurora@redhat.com \
--to=vaurora@redhat.com \
--cc=jblunck@suse.de \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).