Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  AFS: Use i_generation not i_version for the vnode uniquifier
  AFS: Set s_id in the superblock to the volume name
  vfs: Fix data corruption after failed write in __block_write_begin()
  afs: afs_fill_page reads too much, or wrong data
  VFS: Fix vfsmount overput on simultaneous automount
  fix wrong iput on d_inode introduced by e6bc45d6
  Delay struct net freeing while there's a sysfs instance refering to it
  afs: fix sget() races, close leak on umount
  ubifs: fix sget races
  ubifs: split allocation of ubifs_info into a separate function
  fix leak in proc_set_super()

fs/afs/dir.c

@@ -584,11 +584,11 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 
 success:
 	d_add(dentry, inode);
-	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%llu }",
+	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
 	       fid.vnode,
 	       fid.unique,
 	       dentry->d_inode->i_ino,
-	       (unsigned long long)dentry->d_inode->i_version);
+	       dentry->d_inode->i_generation);
 
 	return NULL;
 }
@@ -671,10 +671,10 @@ static int afs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
 		 * been deleted and replaced, and the original vnode ID has
 		 * been reused */
 		if (fid.unique != vnode->fid.unique) {
-			_debug("%s: file deleted (uq %u -> %u I:%llu)",
+			_debug("%s: file deleted (uq %u -> %u I:%u)",
 			       dentry->d_name.name, fid.unique,
 			       vnode->fid.unique,
-			       (unsigned long long)dentry->d_inode->i_version);
+			       dentry->d_inode->i_generation);
 			spin_lock(&vnode->lock);
 			set_bit(AFS_VNODE_DELETED, &vnode->flags);
 			spin_unlock(&vnode->lock);

fs/afs/fsclient.c

@@ -89,7 +89,7 @@ static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
 			i_size_write(&vnode->vfs_inode, size);
 			vnode->vfs_inode.i_uid = status->owner;
 			vnode->vfs_inode.i_gid = status->group;
-			vnode->vfs_inode.i_version = vnode->fid.unique;
+			vnode->vfs_inode.i_generation = vnode->fid.unique;
 			vnode->vfs_inode.i_nlink = status->nlink;
 
 			mode = vnode->vfs_inode.i_mode;
@@ -102,6 +102,7 @@ static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
 		vnode->vfs_inode.i_ctime.tv_sec	= status->mtime_server;
 		vnode->vfs_inode.i_mtime	= vnode->vfs_inode.i_ctime;
 		vnode->vfs_inode.i_atime	= vnode->vfs_inode.i_ctime;
+		vnode->vfs_inode.i_version	= data_version;
 	}
 
 	expected_version = status->data_version;

fs/afs/inode.c

@@ -75,7 +75,8 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	inode->i_ctime.tv_nsec	= 0;
 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
 	inode->i_blocks		= 0;
-	inode->i_version	= vnode->fid.unique;
+	inode->i_generation	= vnode->fid.unique;
+	inode->i_version	= vnode->status.data_version;
 	inode->i_mapping->a_ops	= &afs_fs_aops;
 
 	/* check to see whether a symbolic link is really a mountpoint */
@@ -100,7 +101,7 @@ static int afs_iget5_test(struct inode *inode, void *opaque)
 	struct afs_iget_data *data = opaque;
 
 	return inode->i_ino == data->fid.vnode &&
-		inode->i_version == data->fid.unique;
+		inode->i_generation == data->fid.unique;
 }
 
 /*
@@ -122,7 +123,7 @@ static int afs_iget5_set(struct inode *inode, void *opaque)
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 
 	inode->i_ino = data->fid.vnode;
-	inode->i_version = data->fid.unique;
+	inode->i_generation = data->fid.unique;
 	vnode->fid = data->fid;
 	vnode->volume = data->volume;
 
@@ -380,8 +381,7 @@ int afs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 
 	inode = dentry->d_inode;
 
-	_enter("{ ino=%lu v=%llu }", inode->i_ino,
-		(unsigned long long)inode->i_version);
+	_enter("{ ino=%lu v=%u }", inode->i_ino, inode->i_generation);
 
 	generic_fillattr(inode, stat);
 	return 0;

fs/afs/super.c

@@ -31,8 +31,8 @@
 static void afs_i_init_once(void *foo);
 static struct dentry *afs_mount(struct file_system_type *fs_type,
 		      int flags, const char *dev_name, void *data);
+static void afs_kill_super(struct super_block *sb);
 static struct inode *afs_alloc_inode(struct super_block *sb);
-static void afs_put_super(struct super_block *sb);
 static void afs_destroy_inode(struct inode *inode);
 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
 
@@ -40,7 +40,7 @@ struct file_system_type afs_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "afs",
 	.mount		= afs_mount,
-	.kill_sb	= kill_anon_super,
+	.kill_sb	= afs_kill_super,
 	.fs_flags	= 0,
 };
 
@@ -50,7 +50,6 @@ static const struct super_operations afs_super_ops = {
 	.drop_inode	= afs_drop_inode,
 	.destroy_inode	= afs_destroy_inode,
 	.evict_inode	= afs_evict_inode,
-	.put_super	= afs_put_super,
 	.show_options	= generic_show_options,
 };
 
@@ -282,19 +281,25 @@ static int afs_parse_device_name(struct afs_mount_params *params,
  */
 static int afs_test_super(struct super_block *sb, void *data)
 {
-	struct afs_mount_params *params = data;
+	struct afs_super_info *as1 = data;
 	struct afs_super_info *as = sb->s_fs_info;
 
-	return as->volume == params->volume;
+	return as->volume == as1->volume;
+}
+
+static int afs_set_super(struct super_block *sb, void *data)
+{
+	sb->s_fs_info = data;
+	return set_anon_super(sb, NULL);
 }
 
 /*
  * fill in the superblock
  */
-static int afs_fill_super(struct super_block *sb, void *data)
+static int afs_fill_super(struct super_block *sb,
+			  struct afs_mount_params *params)
 {
-	struct afs_mount_params *params = data;
-	struct afs_super_info *as = NULL;
+	struct afs_super_info *as = sb->s_fs_info;
 	struct afs_fid fid;
 	struct dentry *root = NULL;
 	struct inode *inode = NULL;
@@ -302,23 +307,13 @@ static int afs_fill_super(struct super_block *sb, void *data)
 
 	_enter("");
 
-	/* allocate a superblock info record */
-	as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
-	if (!as) {
-		_leave(" = -ENOMEM");
-		return -ENOMEM;
-	}
-
-	afs_get_volume(params->volume);
-	as->volume = params->volume;
-
 	/* fill in the superblock */
 	sb->s_blocksize		= PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits	= PAGE_CACHE_SHIFT;
 	sb->s_magic		= AFS_FS_MAGIC;
 	sb->s_op		= &afs_super_ops;
-	sb->s_fs_info		= as;
 	sb->s_bdi		= &as->volume->bdi;
+	strlcpy(sb->s_id, as->volume->vlocation->vldb.name, sizeof(sb->s_id));
 
 	/* allocate the root inode and dentry */
 	fid.vid		= as->volume->vid;
@@ -326,7 +321,7 @@ static int afs_fill_super(struct super_block *sb, void *data)
 	fid.unique	= 1;
 	inode = afs_iget(sb, params->key, &fid, NULL, NULL);
 	if (IS_ERR(inode))
-		goto error_inode;
+		return PTR_ERR(inode);
 
 	if (params->autocell)
 		set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
@@ -342,16 +337,8 @@ static int afs_fill_super(struct super_block *sb, void *data)
 	_leave(" = 0");
 	return 0;
 
-error_inode:
-	ret = PTR_ERR(inode);
-	inode = NULL;
 error:
 	iput(inode);
-	afs_put_volume(as->volume);
-	kfree(as);
-
-	sb->s_fs_info = NULL;
-
 	_leave(" = %d", ret);
 	return ret;
 }
@@ -367,6 +354,7 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
 	struct afs_volume *vol;
 	struct key *key;
 	char *new_opts = kstrdup(options, GFP_KERNEL);
+	struct afs_super_info *as;
 	int ret;
 
 	_enter(",,%s,%p", dev_name, options);
@@ -399,12 +387,22 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
 		ret = PTR_ERR(vol);
 		goto error;
 	}
-	params.volume = vol;
+
+	/* allocate a superblock info record */
+	as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
+	if (!as) {
+		ret = -ENOMEM;
+		afs_put_volume(vol);
+		goto error;
+	}
+	as->volume = vol;
 
 	/* allocate a deviceless superblock */
-	sb = sget(fs_type, afs_test_super, set_anon_super, &params);
+	sb = sget(fs_type, afs_test_super, afs_set_super, as);
 	if (IS_ERR(sb)) {
 		ret = PTR_ERR(sb);
+		afs_put_volume(vol);
+		kfree(as);
 		goto error;
 	}
 
@@ -422,16 +420,16 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
 	} else {
 		_debug("reuse");
 		ASSERTCMP(sb->s_flags, &, MS_ACTIVE);
+		afs_put_volume(vol);
+		kfree(as);
 	}
 
-	afs_put_volume(params.volume);
 	afs_put_cell(params.cell);
 	kfree(new_opts);
 	_leave(" = 0 [%p]", sb);
 	return dget(sb->s_root);
 
 error:
-	afs_put_volume(params.volume);
 	afs_put_cell(params.cell);
 	key_put(params.key);
 	kfree(new_opts);
@@ -439,18 +437,12 @@ static struct dentry *afs_mount(struct file_system_type *fs_type,
 	return ERR_PTR(ret);
 }
 
-/*
- * finish the unmounting process on the superblock
- */
-static void afs_put_super(struct super_block *sb)
+static void afs_kill_super(struct super_block *sb)
 {
 	struct afs_super_info *as = sb->s_fs_info;
-
-	_enter("");
-
+	kill_anon_super(sb);
 	afs_put_volume(as->volume);
-
-	_leave("");
+	kfree(as);
 }
 
 /*

fs/afs/write.c

@@ -84,23 +84,21 @@ void afs_put_writeback(struct afs_writeback *wb)
  * partly or wholly fill a page that's under preparation for writing
  */
 static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
-			 loff_t pos, unsigned len, struct page *page)
+			 loff_t pos, struct page *page)
 {
 	loff_t i_size;
-	unsigned eof;
 	int ret;
+	int len;
 
-	_enter(",,%llu,%u", (unsigned long long)pos, len);
-
-	ASSERTCMP(len, <=, PAGE_CACHE_SIZE);
+	_enter(",,%llu", (unsigned long long)pos);
 
 	i_size = i_size_read(&vnode->vfs_inode);
-	if (pos + len > i_size)
-		eof = i_size;
+	if (pos + PAGE_CACHE_SIZE > i_size)
+		len = i_size - pos;
 	else
-		eof = PAGE_CACHE_SIZE;
+		len = PAGE_CACHE_SIZE;
 
-	ret = afs_vnode_fetch_data(vnode, key, 0, eof, page);
+	ret = afs_vnode_fetch_data(vnode, key, pos, len, page);
 	if (ret < 0) {
 		if (ret == -ENOENT) {
 			_debug("got NOENT from server"
@@ -153,9 +151,8 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
 	*pagep = page;
 	/* page won't leak in error case: it eventually gets cleaned off LRU */
 
-	if (!PageUptodate(page)) {
-		_debug("not up to date");
-		ret = afs_fill_page(vnode, key, pos, len, page);
+	if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
+		ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
 		if (ret < 0) {
 			kfree(candidate);
 			_leave(" = %d [prep]", ret);

fs/buffer.c

@@ -1902,10 +1902,8 @@ int __block_write_begin(struct page *page, loff_t pos, unsigned len,
 		if (!buffer_uptodate(*wait_bh))
 			err = -EIO;
 	}
-	if (unlikely(err)) {
+	if (unlikely(err))
 		page_zero_new_buffers(page, from, to);
-		ClearPageUptodate(page);
-	}
 	return err;
 }
 EXPORT_SYMBOL(__block_write_begin);

fs/namei.c

@@ -812,6 +812,11 @@ static int follow_automount(struct path *path, unsigned flags,
 	if (!mnt) /* mount collision */
 		return 0;
 
+	if (!*need_mntput) {
+		/* lock_mount() may release path->mnt on error */
+		mntget(path->mnt);
+		*need_mntput = true;
+	}
 	err = finish_automount(mnt, path);
 
 	switch (err) {
@@ -819,12 +824,9 @@ static int follow_automount(struct path *path, unsigned flags,
 		/* Someone else made a mount here whilst we were busy */
 		return 0;
 	case 0:
-		dput(path->dentry);
-		if (*need_mntput)
-			mntput(path->mnt);
+		path_put(path);
 		path->mnt = mnt;
 		path->dentry = dget(mnt->mnt_root);
-		*need_mntput = true;
 		return 0;
 	default:
 		return err;
@@ -844,9 +846,10 @@ static int follow_automount(struct path *path, unsigned flags,
  */
 static int follow_managed(struct path *path, unsigned flags)
 {
+	struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */
 	unsigned managed;
 	bool need_mntput = false;
-	int ret;
+	int ret = 0;
 
 	/* Given that we're not holding a lock here, we retain the value in a
 	 * local variable for each dentry as we look at it so that we don't see
@@ -861,7 +864,7 @@ static int follow_managed(struct path *path, unsigned flags)
 			BUG_ON(!path->dentry->d_op->d_manage);
 			ret = path->dentry->d_op->d_manage(path->dentry, false);
 			if (ret < 0)
-				return ret == -EISDIR ? 0 : ret;
+				break;
 		}
 
 		/* Transit to a mounted filesystem. */
@@ -887,14 +890,19 @@ static int follow_managed(struct path *path, unsigned flags)
 		if (managed & DCACHE_NEED_AUTOMOUNT) {
 			ret = follow_automount(path, flags, &need_mntput);
 			if (ret < 0)
-				return ret == -EISDIR ? 0 : ret;
+				break;
 			continue;
 		}
 
 		/* We didn't change the current path point */
 		break;
 	}
-	return 0;
+
+	if (need_mntput && path->mnt == mnt)
+		mntput(path->mnt);
+	if (ret == -EISDIR)
+		ret = 0;
+	return ret;
 }
 
 int follow_down_one(struct path *path)
@@ -2713,8 +2721,10 @@ static long do_unlinkat(int dfd, const char __user *pathname)
 	error = PTR_ERR(dentry);
 	if (!IS_ERR(dentry)) {
 		/* Why not before? Because we want correct error value */
+		if (nd.last.name[nd.last.len])
+			goto slashes;
 		inode = dentry->d_inode;
-		if (nd.last.name[nd.last.len] || !inode)
+		if (!inode)
 			goto slashes;
 		ihold(inode);
 		error = mnt_want_write(nd.path.mnt);

fs/proc/root.c

@@ -28,11 +28,12 @@ static int proc_test_super(struct super_block *sb, void *data)
 
 static int proc_set_super(struct super_block *sb, void *data)
 {
-	struct pid_namespace *ns;
-
-	ns = (struct pid_namespace *)data;
+	int err = set_anon_super(sb, NULL);
+	if (!err) {
+		struct pid_namespace *ns = (struct pid_namespace *)data;
 		sb->s_fs_info = get_pid_ns(ns);
-	return set_anon_super(sb, NULL);
+	}
+	return err;
 }
 
 static struct dentry *proc_mount(struct file_system_type *fs_type,

fs/sysfs/mount.c

@@ -95,6 +95,14 @@ static int sysfs_set_super(struct super_block *sb, void *data)
 	return error;
 }
 
+static void free_sysfs_super_info(struct sysfs_super_info *info)
+{
+	int type;
+	for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++)
+		kobj_ns_drop(type, info->ns[type]);
+	kfree(info);
+}
+
 static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
@@ -108,11 +116,11 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 		return ERR_PTR(-ENOMEM);
 
 	for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++)
-		info->ns[type] = kobj_ns_current(type);
+		info->ns[type] = kobj_ns_grab_current(type);
 
 	sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info);
 	if (IS_ERR(sb) || sb->s_fs_info != info)
-		kfree(info);
+		free_sysfs_super_info(info);
 	if (IS_ERR(sb))
 		return ERR_CAST(sb);
 	if (!sb->s_root) {
@@ -131,12 +139,11 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
 static void sysfs_kill_sb(struct super_block *sb)
 {
 	struct sysfs_super_info *info = sysfs_info(sb);
-
 	/* Remove the superblock from fs_supers/s_instances
 	 * so we can't find it, before freeing sysfs_super_info.
 	 */
 	kill_anon_super(sb);
-	kfree(info);
+	free_sysfs_super_info(info);
 }
 
 static struct file_system_type sysfs_fs_type = {
@@ -145,28 +152,6 @@ static struct file_system_type sysfs_fs_type = {
 	.kill_sb	= sysfs_kill_sb,
 };
 
-void sysfs_exit_ns(enum kobj_ns_type type, const void *ns)
-{
-	struct super_block *sb;
-
-	mutex_lock(&sysfs_mutex);
-	spin_lock(&sb_lock);
-	list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
-		struct sysfs_super_info *info = sysfs_info(sb);
-		/*
-		 * If we see a superblock on the fs_supers/s_instances
-		 * list the unmount has not completed and sb->s_fs_info
-		 * points to a valid struct sysfs_super_info.
-		 */
-		/* Ignore superblocks with the wrong ns */
-		if (info->ns[type] != ns)
-			continue;
-		info->ns[type] = NULL;
-	}
-	spin_unlock(&sb_lock);
-	mutex_unlock(&sysfs_mutex);
-}
-
 int __init sysfs_init(void)
 {
 	int err = -ENOMEM;

fs/sysfs/sysfs.h

@@ -136,7 +136,7 @@ struct sysfs_addrm_cxt {
  * instance).
  */
 struct sysfs_super_info {
-	const void *ns[KOBJ_NS_TYPES];
+	void *ns[KOBJ_NS_TYPES];
 };
 #define sysfs_info(SB) ((struct sysfs_super_info *)(SB->s_fs_info))
 extern struct sysfs_dirent sysfs_root;

fs/ubifs/super.c

@@ -1848,7 +1848,6 @@ static void ubifs_put_super(struct super_block *sb)
 	bdi_destroy(&c->bdi);
 	ubi_close_volume(c->ubi);
 	mutex_unlock(&c->umount_mutex);
-	kfree(c);
 }
 
 static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
@@ -1971,17 +1970,12 @@ static struct ubi_volume_desc *open_ubi(const char *name, int mode)
 	return ERR_PTR(-EINVAL);
 }
 
-static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
+static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
 {
-	struct ubi_volume_desc *ubi = sb->s_fs_info;
 	struct ubifs_info *c;
-	struct inode *root;
-	int err;
 
 	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
-	if (!c)
-		return -ENOMEM;
-
+	if (c) {
 		spin_lock_init(&c->cnt_lock);
 		spin_lock_init(&c->cs_lock);
 		spin_lock_init(&c->buds_lock);
@@ -2014,18 +2008,27 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 		INIT_LIST_HEAD(&c->orph_new);
 		c->no_chk_data_crc = 1;
 
-	c->vfs_sb = sb;
 		c->highest_inum = UBIFS_FIRST_INO;
 		c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
 
 		ubi_get_volume_info(ubi, &c->vi);
 		ubi_get_device_info(c->vi.ubi_num, &c->di);
+	}
+	return c;
+}
+
+static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct ubifs_info *c = sb->s_fs_info;
+	struct inode *root;
+	int err;
 
+	c->vfs_sb = sb;
 	/* Re-open the UBI device in read-write mode */
 	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
 	if (IS_ERR(c->ubi)) {
 		err = PTR_ERR(c->ubi);
-		goto out_free;
+		goto out;
 	}
 
 	/*
@@ -2091,24 +2094,29 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
 	bdi_destroy(&c->bdi);
 out_close:
 	ubi_close_volume(c->ubi);
-out_free:
-	kfree(c);
+out:
 	return err;
 }
 
 static int sb_test(struct super_block *sb, void *data)
 {
-	dev_t *dev = data;
+	struct ubifs_info *c1 = data;
 	struct ubifs_info *c = sb->s_fs_info;
 
-	return c->vi.cdev == *dev;
+	return c->vi.cdev == c1->vi.cdev;
+}
+
+static int sb_set(struct super_block *sb, void *data)
+{
+	sb->s_fs_info = data;
+	return set_anon_super(sb, NULL);
 }
 
 static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
 			const char *name, void *data)
 {
 	struct ubi_volume_desc *ubi;
-	struct ubi_volume_info vi;
+	struct ubifs_info *c;
 	struct super_block *sb;
 	int err;
 
@@ -2125,19 +2133,24 @@ static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
 			name, (int)PTR_ERR(ubi));
 		return ERR_CAST(ubi);
 	}
-	ubi_get_volume_info(ubi, &vi);
 
-	dbg_gen("opened ubi%d_%d", vi.ubi_num, vi.vol_id);
+	c = alloc_ubifs_info(ubi);
+	if (!c) {
+		err = -ENOMEM;
+		goto out_close;
+	}
 
-	sb = sget(fs_type, &sb_test, &set_anon_super, &vi.cdev);
+	dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
+
+	sb = sget(fs_type, sb_test, sb_set, c);
 	if (IS_ERR(sb)) {
 		err = PTR_ERR(sb);
-		goto out_close;
+		kfree(c);
 	}
 
 	if (sb->s_root) {
 		struct ubifs_info *c1 = sb->s_fs_info;
-
+		kfree(c);
 		/* A new mount point for already mounted UBIFS */
 		dbg_gen("this ubi volume is already mounted");
 		if (!!(flags & MS_RDONLY) != c1->ro_mount) {
@@ -2146,11 +2159,6 @@ static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
 		}
 	} else {
 		sb->s_flags = flags;
-		/*
-		 * Pass 'ubi' to 'fill_super()' in sb->s_fs_info where it is
-		 * replaced by 'c'.
-		 */
-		sb->s_fs_info = ubi;
 		err = ubifs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
 		if (err)
 			goto out_deact;
@@ -2170,11 +2178,18 @@ static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
 	return ERR_PTR(err);
 }
 
+static void kill_ubifs_super(struct super_block *s)
+{
+	struct ubifs_info *c = s->s_fs_info;
+	kill_anon_super(s);
+	kfree(c);
+}
+
 static struct file_system_type ubifs_fs_type = {
 	.name    = "ubifs",
 	.owner   = THIS_MODULE,
 	.mount   = ubifs_mount,
-	.kill_sb = kill_anon_super,
+	.kill_sb = kill_ubifs_super,
 };
 
 /*

include/linux/kobject_ns.h

@@ -32,15 +32,17 @@ enum kobj_ns_type {
 
 /*
  * Callbacks so sysfs can determine namespaces
- *   @current_ns: return calling task's namespace
+ *   @grab_current_ns: return a new reference to calling task's namespace
  *   @netlink_ns: return namespace to which a sock belongs (right?)
  *   @initial_ns: return the initial namespace (i.e. init_net_ns)
+ *   @drop_ns: drops a reference to namespace
  */
 struct kobj_ns_type_operations {
 	enum kobj_ns_type type;
-	const void *(*current_ns)(void);
+	void *(*grab_current_ns)(void);
 	const void *(*netlink_ns)(struct sock *sk);
 	const void *(*initial_ns)(void);
+	void (*drop_ns)(void *);
 };
 
 int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
@@ -48,9 +50,9 @@ int kobj_ns_type_registered(enum kobj_ns_type type);
 const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
 const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
 
-const void *kobj_ns_current(enum kobj_ns_type type);
+void *kobj_ns_grab_current(enum kobj_ns_type type);
 const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
 const void *kobj_ns_initial(enum kobj_ns_type type);
-void kobj_ns_exit(enum kobj_ns_type type, const void *ns);
+void kobj_ns_drop(enum kobj_ns_type type, void *ns);
 
 #endif /* _LINUX_KOBJECT_NS_H */

include/linux/sysfs.h

@@ -177,9 +177,6 @@ struct sysfs_dirent *sysfs_get_dirent(struct sysfs_dirent *parent_sd,
 struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd);
 void sysfs_put(struct sysfs_dirent *sd);
 
-/* Called to clear a ns tag when it is no longer valid */
-void sysfs_exit_ns(enum kobj_ns_type type, const void *tag);
-
 int __must_check sysfs_init(void);
 
 #else /* CONFIG_SYSFS */
@@ -338,10 +335,6 @@ static inline void sysfs_put(struct sysfs_dirent *sd)
 {
 }
 
-static inline void sysfs_exit_ns(int type, const void *tag)
-{
-}
-
 static inline int __must_check sysfs_init(void)
 {
 	return 0;

include/net/net_namespace.h

@@ -35,9 +35,12 @@ struct netns_ipvs;
 #define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
 
 struct net {
-	atomic_t		count;		/* To decided when the network
+	atomic_t		passive;	/* To decided when the network
 						 * namespace should be freed.
 						 */
+	atomic_t		count;		/* To decided when the network
+						 *  namespace should be shut down.
+						 */
 #ifdef NETNS_REFCNT_DEBUG
 	atomic_t		use_count;	/* To track references we
 						 * destroy on demand
@@ -154,6 +157,9 @@ int net_eq(const struct net *net1, const struct net *net2)
 {
 	return net1 == net2;
 }
+
+extern void net_drop_ns(void *);
+
 #else
 
 static inline struct net *get_net(struct net *net)
@@ -175,6 +181,8 @@ int net_eq(const struct net *net1, const struct net *net2)
 {
 	return 1;
 }
+
+#define net_drop_ns NULL
 #endif
 
 

lib/kobject.c

@@ -948,14 +948,14 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj)
 }
 
 
-const void *kobj_ns_current(enum kobj_ns_type type)
+void *kobj_ns_grab_current(enum kobj_ns_type type)
 {
-	const void *ns = NULL;
+	void *ns = NULL;
 
 	spin_lock(&kobj_ns_type_lock);
 	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
 	    kobj_ns_ops_tbl[type])
-		ns = kobj_ns_ops_tbl[type]->current_ns();
+		ns = kobj_ns_ops_tbl[type]->grab_current_ns();
 	spin_unlock(&kobj_ns_type_lock);
 
 	return ns;
@@ -987,23 +987,15 @@ const void *kobj_ns_initial(enum kobj_ns_type type)
 	return ns;
 }
 
-/*
- * kobj_ns_exit - invalidate a namespace tag
- *
- * @type: the namespace type (i.e. KOBJ_NS_TYPE_NET)
- * @ns: the actual namespace being invalidated
- *
- * This is called when a tag is no longer valid.  For instance,
- * when a network namespace exits, it uses this helper to
- * make sure no sb's sysfs_info points to the now-invalidated
- * netns.
- */
-void kobj_ns_exit(enum kobj_ns_type type, const void *ns)
+void kobj_ns_drop(enum kobj_ns_type type, void *ns)
 {
-	sysfs_exit_ns(type, ns);
+	spin_lock(&kobj_ns_type_lock);
+	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
+	    kobj_ns_ops_tbl[type] && kobj_ns_ops_tbl[type]->drop_ns)
+		kobj_ns_ops_tbl[type]->drop_ns(ns);
+	spin_unlock(&kobj_ns_type_lock);
 }
 
-
 EXPORT_SYMBOL(kobject_get);
 EXPORT_SYMBOL(kobject_put);
 EXPORT_SYMBOL(kobject_del);

net/core/net-sysfs.c

@@ -1179,9 +1179,14 @@ static void remove_queue_kobjects(struct net_device *net)
 #endif
 }
 
-static const void *net_current_ns(void)
+static void *net_grab_current_ns(void)
 {
-	return current->nsproxy->net_ns;
+	struct net *ns = current->nsproxy->net_ns;
+#ifdef CONFIG_NET_NS
+	if (ns)
+		atomic_inc(&ns->passive);
+#endif
+	return ns;
 }
 
 static const void *net_initial_ns(void)
@@ -1196,22 +1201,13 @@ static const void *net_netlink_ns(struct sock *sk)
 
 struct kobj_ns_type_operations net_ns_type_operations = {
 	.type = KOBJ_NS_TYPE_NET,
-	.current_ns = net_current_ns,
+	.grab_current_ns = net_grab_current_ns,
 	.netlink_ns = net_netlink_ns,
 	.initial_ns = net_initial_ns,
+	.drop_ns = net_drop_ns,
 };
 EXPORT_SYMBOL_GPL(net_ns_type_operations);
 
-static void net_kobj_ns_exit(struct net *net)
-{
-	kobj_ns_exit(KOBJ_NS_TYPE_NET, net);
-}
-
-static struct pernet_operations kobj_net_ops = {
-	.exit = net_kobj_ns_exit,
-};
-
-
 #ifdef CONFIG_HOTPLUG
 static int netdev_uevent(struct device *d, struct kobj_uevent_env *env)
 {
@@ -1339,6 +1335,5 @@ EXPORT_SYMBOL(netdev_class_remove_file);
 int netdev_kobject_init(void)
 {
 	kobj_ns_type_register(&net_ns_type_operations);
-	register_pernet_subsys(&kobj_net_ops);
 	return class_register(&net_class);
 }

net/core/net_namespace.c

@@ -128,6 +128,7 @@ static __net_init int setup_net(struct net *net)
 	LIST_HEAD(net_exit_list);
 
 	atomic_set(&net->count, 1);
+	atomic_set(&net->passive, 1);
 
 #ifdef NETNS_REFCNT_DEBUG
 	atomic_set(&net->use_count, 0);
@@ -210,6 +211,13 @@ static void net_free(struct net *net)
 	kmem_cache_free(net_cachep, net);
 }
 
+void net_drop_ns(void *p)
+{
+	struct net *ns = p;
+	if (ns && atomic_dec_and_test(&ns->passive))
+		net_free(ns);
+}
+
 struct net *copy_net_ns(unsigned long flags, struct net *old_net)
 {
 	struct net *net;
@@ -230,7 +238,7 @@ struct net *copy_net_ns(unsigned long flags, struct net *old_net)
 	}
 	mutex_unlock(&net_mutex);
 	if (rv < 0) {
-		net_free(net);
+		net_drop_ns(net);
 		return ERR_PTR(rv);
 	}
 	return net;
@@ -286,7 +294,7 @@ static void cleanup_net(struct work_struct *work)
 	/* Finally it is safe to free my network namespace structure */
 	list_for_each_entry_safe(net, tmp, &net_exit_list, exit_list) {
 		list_del_init(&net->exit_list);
-		net_free(net);
+		net_drop_ns(net);
 	}
 }
 static DECLARE_WORK(net_cleanup_work, cleanup_net);