Commit 15932c41 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: defer upper dir lock to tempfile link 



On copy up of regular file using an O_TMPFILE, lock upper dir only
before linking the tempfile in place.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent b9ac5c27

fs/overlayfs/copy_up.c

+38 −29
Original line number Diff line number Diff line
@@ -316,6 +316,35 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 
	return err;

}



static int ovl_install_temp(struct dentry *workdir, struct dentry *upperdir,

			    struct dentry *dentry,

			    struct dentry *temp, struct kstat *pstat,

			    bool tmpfile, struct dentry **newdentry)

{

	int err;

	struct dentry *upper;

	struct inode *udir = d_inode(upperdir);



	upper = lookup_one_len(dentry->d_name.name, upperdir,

			       dentry->d_name.len);

	if (IS_ERR(upper))

		return PTR_ERR(upper);



	if (tmpfile)

		err = ovl_do_link(temp, udir, upper, true);

	else

		err = ovl_do_rename(d_inode(workdir), temp, udir, upper, 0);



	/* Restore timestamps on parent (best effort) */

	if (!err) {

		ovl_set_timestamps(upperdir, pstat);

		*newdentry = dget(tmpfile ? upper : temp);

	}

	dput(upper);



	return err;

}



static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,

			      struct dentry *dentry, struct path *lowerpath,

			      struct kstat *stat, const char *link,
@@ -324,7 +353,6 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, 
	struct inode *wdir = workdir->d_inode;

	struct inode *udir = upperdir->d_inode;

	struct dentry *newdentry = NULL;

	struct dentry *upper = NULL;

	struct dentry *temp = NULL;

	int err;

	const struct cred *old_creds = NULL;
@@ -371,16 +399,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, 
		BUG_ON(upperpath.dentry != NULL);

		upperpath.dentry = temp;



		if (tmpfile) {

			inode_unlock(udir);

			err = ovl_copy_up_data(lowerpath, &upperpath,

					       stat->size);

			inode_lock_nested(udir, I_MUTEX_PARENT);

		} else {

			err = ovl_copy_up_data(lowerpath, &upperpath,

					       stat->size);

		}



		err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);

		if (err)

			goto out_cleanup;

	}
@@ -408,29 +427,21 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, 
			goto out_cleanup;

	}



	upper = lookup_one_len(dentry->d_name.name, upperdir,

			       dentry->d_name.len);

	if (IS_ERR(upper)) {

		err = PTR_ERR(upper);

		upper = NULL;

		goto out_cleanup;

	if (tmpfile) {

		inode_lock_nested(udir, I_MUTEX_PARENT);

		err = ovl_install_temp(workdir, upperdir, dentry, temp, pstat,

				       tmpfile, &newdentry);

		inode_unlock(udir);

	} else {

		err = ovl_install_temp(workdir, upperdir, dentry, temp, pstat,

				       tmpfile, &newdentry);

	}



	if (tmpfile)

		err = ovl_do_link(temp, udir, upper, true);

	else

		err = ovl_do_rename(wdir, temp, udir, upper, 0);

	if (err)

		goto out_cleanup;



	newdentry = dget(tmpfile ? upper : temp);

	ovl_inode_update(d_inode(dentry), newdentry);



	/* Restore timestamps on parent (best effort) */

	ovl_set_timestamps(upperdir, pstat);

out:

	dput(temp);

	dput(upper);

	return err;



out_cleanup:
@@ -496,10 +507,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, 
			goto out_done;

		}



		inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);

		err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,

					 stat, link, &pstat, true);

		inode_unlock(upperdir->d_inode);

		ovl_copy_up_end(dentry);

		goto out_done;

	}

fs/overlayfs/util.c

+0 −1
Original line number Diff line number Diff line
@@ -236,7 +236,6 @@ void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) 
{

	struct inode *upperinode = d_inode(upperdentry);



	WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));

	WARN_ON(OVL_I(inode)->__upperdentry);



	/*