From: Al Viro <viro@ZenIV.linux.org.uk>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-afs@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 20/32] vfs: Make close() unmount the attached mount if so flagged [ver #8]
Date: Fri, 1 Jun 2018 04:18:29 +0100 [thread overview]
Message-ID: <20180601031829.GQ30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180601015255.GP30522@ZenIV.linux.org.uk>
FWIW, this on top of your current branch (I'll fold and reorder) gets
your move_mount(2) test work, AFAICS:
diff --git a/fs/file_table.c b/fs/file_table.c
index 06e979e1347e..6dd9760b3ddc 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -200,9 +200,6 @@ static void __fput(struct file *file)
eventpoll_release(file);
locks_remove_file(file);
- if (unlikely(file->f_mode & FMODE_NEED_UNMOUNT))
- drop_collected_mounts(mnt);
-
ima_file_free(file);
if (unlikely(file->f_flags & FASYNC)) {
if (file->f_op->fasync)
@@ -228,7 +225,10 @@ static void __fput(struct file *file)
file->f_inode = NULL;
file_free(file);
dput(dentry);
- mntput(mnt);
+ if (unlikely(file->f_mode & FMODE_NEED_UNMOUNT))
+ umount_on_fput(mnt);
+ else
+ mntput(mnt);
}
static LLIST_HEAD(delayed_fput_list);
diff --git a/fs/internal.h b/fs/internal.h
index 6d0538af32d9..7ec629916f6d 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -75,7 +75,7 @@ extern struct vfsmount *lookup_mnt(const struct path *);
extern int finish_automount(struct vfsmount *, struct path *);
extern int sb_prepare_remount_readonly(struct super_block *);
-extern int copy_mount_for_o_path(struct path *, struct path *, bool);
+extern int copy_mount_for_o_path(struct path *, bool);
extern void __init mnt_init(void);
@@ -86,6 +86,8 @@ extern void __mnt_drop_write(struct vfsmount *);
extern void __mnt_drop_write_file(struct file *);
extern void mnt_drop_write_file_path(struct file *);
+extern void umount_on_fput(struct vfsmount *);
+
/*
* fs_struct.c
*/
diff --git a/fs/namei.c b/fs/namei.c
index 7430e000c1d2..b1c451b6b508 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3454,28 +3454,20 @@ static int do_tmpfile(struct nameidata *nd, unsigned flags,
static int do_o_path(struct nameidata *nd, unsigned flags, struct file *file)
{
- struct path path, tmp;
- int error;
-
- error = path_lookupat(nd, flags, &path);
+ struct path path;
+ int error = path_lookupat(nd, flags, &path);
if (error)
return error;
if (file->f_flags & O_CLONE_MOUNT) {
- error = copy_mount_for_o_path(
- &path, &tmp, !(file->f_flags & O_NON_RECURSIVE));
- path_put(&path);
+ error = copy_mount_for_o_path(&path,
+ !(file->f_flags & O_NON_RECURSIVE));
if (error < 0)
return error;
- path = tmp;
}
audit_inode(nd->name, path.dentry, 0);
error = vfs_open(&path, file, current_cred());
- if (error < 0 &&
- (flags & O_CLONE_MOUNT) &&
- !(file->f_mode & FMODE_NEED_UNMOUNT))
- __detach_mounts(path.dentry);
path_put(&path);
return error;
}
diff --git a/fs/namespace.c b/fs/namespace.c
index dd9cf81c2aea..74c68a23d088 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1793,7 +1793,7 @@ struct vfsmount *collect_mounts(const struct path *path)
return &tree->mnt;
}
-void drop_collected_mounts(struct vfsmount *mnt)
+void umount_on_fput(struct vfsmount *mnt)
{
namespace_lock();
lock_mount_hash();
@@ -1803,6 +1803,15 @@ void drop_collected_mounts(struct vfsmount *mnt)
namespace_unlock();
}
+void drop_collected_mounts(struct vfsmount *mnt)
+{
+ namespace_lock();
+ lock_mount_hash();
+ umount_tree(real_mount(mnt), UMOUNT_SYNC);
+ unlock_mount_hash();
+ namespace_unlock();
+}
+
/**
* clone_private_mount - create a private clone of a path
*
@@ -2153,6 +2162,30 @@ static bool has_locked_children(struct mount *mnt, struct dentry *dentry)
return false;
}
+static struct mount *__do_loopback(struct path *old_path, int recurse)
+{
+ struct mount *mnt = ERR_PTR(-EINVAL), *old = real_mount(old_path->mnt);
+
+ if (IS_MNT_UNBINDABLE(old))
+ return mnt;
+
+ if (!check_mnt(old) && old_path->dentry->d_op != &ns_dentry_operations)
+ return mnt;
+
+ if (!recurse && has_locked_children(old, old_path->dentry))
+ return mnt;
+
+ if (recurse)
+ mnt = copy_tree(old, old_path->dentry, CL_COPY_MNT_NS_FILE);
+ else
+ mnt = clone_mnt(old, old_path->dentry, 0);
+
+ if (!IS_ERR(mnt))
+ mnt->mnt.mnt_flags &= ~MNT_LOCKED;
+
+ return mnt;
+}
+
/*
* do loopback mount.
*/
@@ -2160,7 +2193,7 @@ static int do_loopback(struct path *path, const char *old_name,
int recurse)
{
struct path old_path;
- struct mount *mnt = NULL, *old, *parent;
+ struct mount *mnt = NULL, *parent;
struct mountpoint *mp;
int err;
if (!old_name || !*old_name)
@@ -2174,38 +2207,21 @@ static int do_loopback(struct path *path, const char *old_name,
goto out;
mp = lock_mount(path);
- err = PTR_ERR(mp);
- if (IS_ERR(mp))
+ if (IS_ERR(mp)) {
+ err = PTR_ERR(mp);
goto out;
+ }
- old = real_mount(old_path.mnt);
parent = real_mount(path->mnt);
-
- err = -EINVAL;
- if (IS_MNT_UNBINDABLE(old))
- goto out2;
-
if (!check_mnt(parent))
goto out2;
- if (!check_mnt(old) && old_path.dentry->d_op != &ns_dentry_operations)
- goto out2;
-
- if (!recurse && has_locked_children(old, old_path.dentry))
- goto out2;
-
- if (recurse)
- mnt = copy_tree(old, old_path.dentry, CL_COPY_MNT_NS_FILE);
- else
- mnt = clone_mnt(old, old_path.dentry, 0);
-
+ mnt = __do_loopback(&old_path, recurse);
if (IS_ERR(mnt)) {
err = PTR_ERR(mnt);
goto out2;
}
- mnt->mnt.mnt_flags &= ~MNT_LOCKED;
-
err = graft_tree(mnt, parent, mp);
if (err) {
lock_mount_hash();
@@ -2223,44 +2239,16 @@ static int do_loopback(struct path *path, const char *old_name,
* Copy the mount or mount subtree at the specified path for
* open(O_PATH|O_CLONE_MOUNT).
*/
-int copy_mount_for_o_path(struct path *from, struct path *to, bool recurse)
+int copy_mount_for_o_path(struct path *path, bool recurse)
{
- struct mountpoint *mp;
- struct mount *mnt = NULL, *f = real_mount(from->mnt);
- int ret;
-
- mp = lock_mount(from);
- if (IS_ERR(mp))
- return PTR_ERR(mp);
-
- ret = -EINVAL;
- if (IS_MNT_UNBINDABLE(f))
- goto out_unlock;
-
- if (!check_mnt(f) && from->dentry->d_op != &ns_dentry_operations)
- goto out_unlock;
-
- if (!recurse && has_locked_children(f, from->dentry))
- goto out_unlock;
-
- if (recurse)
- mnt = copy_tree(f, from->dentry, CL_COPY_MNT_NS_FILE);
- else
- mnt = clone_mnt(f, from->dentry, 0);
+ struct mount *mnt = __do_loopback(path, recurse);
if (IS_ERR(mnt)) {
- ret = PTR_ERR(mnt);
- goto out_unlock;
+ path_put(path);
+ return PTR_ERR(mnt);
}
-
- mnt->mnt.mnt_flags &= ~MNT_LOCKED;
-
- to->mnt = &mnt->mnt;
- to->dentry = dget(from->dentry);
- ret = 0;
-
-out_unlock:
- unlock_mount(mp);
- return ret;
+ mntput(path->mnt);
+ path->mnt = &mnt->mnt;
+ return 0;
}
static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
@@ -2398,11 +2386,12 @@ static inline int tree_contains_unbindable(struct mount *mnt)
static int do_move_mount(struct path *old_path, struct path *new_path)
{
- struct path parent_path;
+ struct path parent_path = {.mnt = NULL, .dentry = NULL};
struct mount *p;
struct mount *old;
struct mountpoint *mp;
int err;
+ bool attached;
mp = lock_mount(new_path);
err = PTR_ERR(mp);
@@ -2420,10 +2409,11 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
if (old->mnt_ns && !check_mnt(old))
goto out1;
+ attached = mnt_has_parent(old);
/* We need to allow open(O_PATH|O_CLONE_MOUNT) or fsmount() followed by
* move_mount(), but mustn't allow "/" to be moved.
*/
- if (old->mnt_ns && !mnt_has_parent(old))
+ if (old->mnt_ns && !attached)
goto out1;
if (old->mnt.mnt_flags & MNT_LOCKED)
@@ -2438,7 +2428,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
/*
* Don't move a mount residing in a shared parent.
*/
- if (IS_MNT_SHARED(old->mnt_parent))
+ if (attached && IS_MNT_SHARED(old->mnt_parent))
goto out1;
/*
* Don't move a mount tree containing unbindable mounts to a destination
@@ -2452,7 +2442,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
goto out1;
err = attach_recursive_mnt(old, real_mount(new_path->mnt), mp,
- &parent_path);
+ attached ? &parent_path : NULL);
if (err)
goto out1;
next prev parent reply other threads:[~2018-06-01 3:18 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 0:05 [PATCH 00/32] VFS: Introduce filesystem context [ver #8] David Howells
2018-05-25 0:05 ` [PATCH 01/32] VFS: Suppress MS_* flag defs within the kernel unless explicitly enabled " David Howells
2018-05-25 0:05 ` [PATCH 02/32] vfs: Provide documentation for new mount API " David Howells
2018-05-25 0:05 ` [PATCH 03/32] VFS: Introduce the basic header for the new mount API's filesystem context " David Howells
2018-05-31 23:11 ` Al Viro
2018-05-31 23:13 ` Al Viro
2018-05-25 0:05 ` [PATCH 04/32] VFS: Add LSM hooks for the new mount API " David Howells
2018-05-25 0:05 ` [PATCH 05/32] selinux: Implement the new mount API LSM hooks " David Howells
2018-05-25 0:06 ` [PATCH 06/32] smack: Implement filesystem context security " David Howells
2018-05-25 0:06 ` [PATCH 07/32] apparmor: Implement security hooks for the new mount API " David Howells
2018-05-25 0:06 ` [PATCH 08/32] tomoyo: " David Howells
2018-05-25 0:06 ` [PATCH 09/32] VFS: Require specification of size of mount data for internal mounts " David Howells
2018-05-25 0:06 ` [PATCH 10/32] VFS: Implement a filesystem superblock creation/configuration context " David Howells
2018-06-07 19:50 ` Miklos Szeredi
2018-07-03 18:33 ` Eric Biggers
2018-07-03 21:53 ` David Howells
2018-07-03 21:58 ` Al Viro
2018-07-03 22:06 ` David Howells
2018-05-25 0:06 ` [PATCH 11/32] VFS: Remove unused code after filesystem context changes " David Howells
2018-05-25 0:06 ` [PATCH 12/32] procfs: Move proc_fill_super() to fs/proc/root.c " David Howells
2018-05-25 0:06 ` [PATCH 13/32] proc: Add fs_context support to procfs " David Howells
2018-05-25 0:06 ` [PATCH 14/32] ipc: Convert mqueue fs to fs_context " David Howells
2018-05-25 0:07 ` [PATCH 15/32] cpuset: Use " David Howells
2018-05-25 0:07 ` [PATCH 16/32] kernfs, sysfs, cgroup, intel_rdt: Support " David Howells
2018-06-21 18:47 ` [16/32] " Andrei Vagin
2018-06-22 12:52 ` David Howells
2018-06-22 15:30 ` Andrei Vagin
2018-06-22 16:57 ` Andrei Vagin
2018-06-23 23:34 ` David Howells
2018-05-25 0:07 ` [PATCH 17/32] hugetlbfs: Convert to " David Howells
2018-05-25 0:07 ` [PATCH 18/32] VFS: Remove kern_mount_data() " David Howells
2018-05-25 0:07 ` [PATCH 19/32] VFS: Implement fsopen() to prepare for a mount " David Howells
2018-05-31 21:25 ` Al Viro
2018-05-25 0:07 ` [PATCH 20/32] vfs: Make close() unmount the attached mount if so flagged " David Howells
2018-05-31 19:19 ` Al Viro
2018-05-31 19:26 ` Al Viro
2018-06-01 1:52 ` Al Viro
2018-06-01 3:18 ` Al Viro [this message]
2018-06-01 5:16 ` Al Viro
2018-05-25 0:07 ` [PATCH 21/32] VFS: Implement fsmount() to effect a pre-configured mount " David Howells
2018-06-04 15:05 ` Arnd Bergmann
2018-06-04 15:24 ` David Howells
2018-05-25 0:07 ` [PATCH 22/32] vfs: Provide an fspick() system call " David Howells
2018-05-25 0:07 ` [PATCH 23/32] VFS: Implement logging through fs_context " David Howells
2018-05-25 1:48 ` Joe Perches
2018-05-25 0:07 ` [PATCH 24/32] vfs: Add some logging to the core users of the fs_context log " David Howells
2018-05-25 0:08 ` [PATCH 25/32] afs: Add fs_context support " David Howells
2018-05-25 0:08 ` [PATCH 26/32] afs: Use fs_context to pass parameters over automount " David Howells
2018-06-07 1:58 ` Goldwyn Rodrigues
2018-06-07 20:45 ` David Howells
2018-05-25 0:08 ` [PATCH 27/32] vfs: Use a 'struct fd_cookie *' type for light fd handling " David Howells
2018-05-25 0:08 ` [PATCH 28/32] vfs: Store the fd_cookie in nameidata, not the dfd int " David Howells
2018-05-25 0:08 ` [PATCH 29/32] vfs: Don't mix FMODE_* flags with O_* flags " David Howells
2018-05-25 0:08 ` [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) " David Howells
2018-06-01 6:26 ` Christoph Hellwig
2018-06-01 6:39 ` Al Viro
2018-06-01 8:27 ` David Howells
2018-06-02 3:09 ` Al Viro
2018-06-02 3:42 ` Al Viro
2018-06-02 4:04 ` Al Viro
2018-06-02 15:45 ` David Howells
2018-06-02 17:49 ` Al Viro
2018-06-03 0:55 ` [PATCH][RFC] open_tree(2) (was Re: [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) [ver #8]) Al Viro
2018-06-04 10:34 ` Miklos Szeredi
2018-06-04 15:52 ` Al Viro
2018-06-04 15:59 ` Al Viro
2018-06-04 19:27 ` Miklos Szeredi
2018-06-04 15:27 ` David Howells
2018-06-04 17:16 ` Matthew Wilcox
2018-06-04 17:35 ` Al Viro
2018-06-04 19:38 ` Miklos Szeredi
2018-06-01 8:02 ` [PATCH 30/32] vfs: Allow cloning of a mount tree with open(O_PATH|O_CLONE_MOUNT) [ver #8] Amir Goldstein
2018-06-01 8:42 ` David Howells
2018-05-25 0:08 ` [PATCH 31/32] [RFC] fs: Add a move_mount() system call " David Howells
2018-05-31 21:20 ` Al Viro
2018-05-25 0:08 ` [PATCH 32/32] [RFC] fsinfo: Add a system call to allow querying of filesystem information " David Howells
2018-06-04 13:10 ` Arnd Bergmann
2018-06-04 15:01 ` David Howells
2018-06-04 16:00 ` Arnd Bergmann
2018-06-04 19:03 ` David Howells
2018-06-04 20:45 ` Arnd Bergmann
2018-05-31 20:56 ` Test program for move_mount() David Howells
2018-05-31 20:57 ` fsinfo test program David Howells
2018-06-15 4:18 ` [PATCH 00/32] VFS: Introduce filesystem context [ver #8] Eric W. Biederman
2018-06-18 20:30 ` David Howells
2018-06-18 21:33 ` Eric W. Biederman
2018-06-18 23:33 ` Theodore Y. Ts'o
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