ovl: copy up of disconnected dentries (aa3ff3c1) · Commits · 戴 / test

fs/overlayfs/copy_up.c

+41 −15

Original line number	Original line	Diff line number	Diff line
	@@ -450,7 +450,10 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c)
	}		}
	}		}
	inode_unlock(udir);		inode_unlock(udir);
	ovl_set_nlink_upper(c->dentry);		if (err)
			return err;

			err = ovl_set_nlink_upper(c->dentry);

	return err;		return err;
	}		}
	@@ -655,6 +658,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
	err = ovl_get_index_name(c->lowerpath.dentry, &c->destname);		err = ovl_get_index_name(c->lowerpath.dentry, &c->destname);
	if (err)		if (err)
	return err;		return err;
			} else if (WARN_ON(!c->parent)) {
			/* Disconnected dentry must be copied up to index dir */
			return -EIO;
	} else {		} else {
	/*		/*
	* Mark parent "impure" because it may now contain non-pure		* Mark parent "impure" because it may now contain non-pure
	@@ -677,12 +683,17 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
	}		}
	}		}

	if (!err && c->indexed)
			if (err)
			goto out;

			if (c->indexed)
	ovl_set_flag(OVL_INDEX, d_inode(c->dentry));		ovl_set_flag(OVL_INDEX, d_inode(c->dentry));

	if (to_index) {		if (to_index) {
	kfree(c->destname.name);		/* Initialize nlink for copy up of disconnected dentry */
	} else if (!err) {		err = ovl_set_nlink_upper(c->dentry);
			} else {
	struct inode *udir = d_inode(c->destdir);		struct inode *udir = d_inode(c->destdir);

	/* Restore timestamps on parent (best effort) */		/* Restore timestamps on parent (best effort) */
	@@ -693,6 +704,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
	ovl_dentry_set_upper_alias(c->dentry);		ovl_dentry_set_upper_alias(c->dentry);
	}		}

			out:
			if (to_index)
			kfree(c->destname.name);
	return err;		return err;
	}		}

	@@ -717,14 +731,17 @@ static int ovl_copy_up_one(struct dentry parent, struct dentry dentry,
	if (err)		if (err)
	return err;		return err;

			if (parent) {
	ovl_path_upper(parent, &parentpath);		ovl_path_upper(parent, &parentpath);
	ctx.destdir = parentpath.dentry;		ctx.destdir = parentpath.dentry;
	ctx.destname = dentry->d_name;		ctx.destname = dentry->d_name;

	err = vfs_getattr(&parentpath, &ctx.pstat,		err = vfs_getattr(&parentpath, &ctx.pstat,
	STATX_ATIME \| STATX_MTIME, AT_STATX_SYNC_AS_STAT);		STATX_ATIME \| STATX_MTIME,
			AT_STATX_SYNC_AS_STAT);
	if (err)		if (err)
	return err;		return err;
			}

	/* maybe truncate regular file. this has no effect on dirs */		/* maybe truncate regular file. this has no effect on dirs */
	if (flags & O_TRUNC)		if (flags & O_TRUNC)
	@@ -745,7 +762,7 @@ static int ovl_copy_up_one(struct dentry parent, struct dentry dentry,
	} else {		} else {
	if (!ovl_dentry_upper(dentry))		if (!ovl_dentry_upper(dentry))
	err = ovl_do_copy_up(&ctx);		err = ovl_do_copy_up(&ctx);
	if (!err && !ovl_dentry_has_upper_alias(dentry))		if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
	err = ovl_link_up(&ctx);		err = ovl_link_up(&ctx);
	ovl_copy_up_end(dentry);		ovl_copy_up_end(dentry);
	}		}
	@@ -758,10 +775,19 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
	{		{
	int err = 0;		int err = 0;
	const struct cred *old_cred = ovl_override_creds(dentry->d_sb);		const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
			bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);

			/*
			* With NFS export, copy up can get called for a disconnected non-dir.
			* In this case, we will copy up lower inode to index dir without
			* linking it to upper dir.
			*/
			if (WARN_ON(disconnected && d_is_dir(dentry)))
			return -EIO;

	while (!err) {		while (!err) {
	struct dentry *next;		struct dentry *next;
	struct dentry *parent;		struct dentry *parent = NULL;

	/*		/*
	* Check if copy-up has happened as well as for upper alias (in		* Check if copy-up has happened as well as for upper alias (in
	@@ -777,12 +803,12 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
	* with rename.		* with rename.
	*/		*/
	if (ovl_dentry_upper(dentry) &&		if (ovl_dentry_upper(dentry) &&
	ovl_dentry_has_upper_alias(dentry))		(ovl_dentry_has_upper_alias(dentry) \|\| disconnected))
	break;		break;

	next = dget(dentry);		next = dget(dentry);
	/* find the topmost dentry not yet copied up */		/* find the topmost dentry not yet copied up */
	for (;;) {		for (; !disconnected;) {
	parent = dget_parent(next);		parent = dget_parent(next);

	if (ovl_dentry_upper(parent))		if (ovl_dentry_upper(parent))

fs/overlayfs/inode.c

+3 −1

Original line number	Original line	Diff line number	Diff line
	@@ -351,8 +351,10 @@ struct posix_acl ovl_get_acl(struct inode inode, int type)

	static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)		static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
	{		{
			/* Copy up of disconnected dentry does not set upper alias */
	if (ovl_dentry_upper(dentry) &&		if (ovl_dentry_upper(dentry) &&
	ovl_dentry_has_upper_alias(dentry))		(ovl_dentry_has_upper_alias(dentry) \|\|
			(dentry->d_flags & DCACHE_DISCONNECTED)))
	return false;		return false;

	if (special_file(d_inode(dentry)->i_mode))		if (special_file(d_inode(dentry)->i_mode))

fs/overlayfs/util.c

+4 −3

Original line number	Original line	Diff line number	Diff line
	@@ -229,9 +229,10 @@ void ovl_dentry_set_opaque(struct dentry *dentry)
	}		}

	/*		/*
	* For hard links it's possible for ovl_dentry_upper() to return positive, while		* For hard links and decoded file handles, it's possible for ovl_dentry_upper()
	* there's no actual upper alias for the inode. Copy up code needs to know		* to return positive, while there's no actual upper alias for the inode.
	* about the existence of the upper alias, so it can't use ovl_dentry_upper().		* Copy up code needs to know about the existence of the upper alias, so it
			* can't use ovl_dentry_upper().
	*/		*/
	bool ovl_dentry_has_upper_alias(struct dentry *dentry)		bool ovl_dentry_has_upper_alias(struct dentry *dentry)
	{		{

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