/*
 * decide if a new whiteout for @dentry is necessary or not.
 * when it is necessary, prepare the parent dir for the upper branch whose
 * branch index is @bcpup for creation. the actual creation of the whiteout will
 * be done by caller.
 * return value:
 * 0: wh is unnecessary
 * plus: wh is necessary
 * minus: error
 */
int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
{
	int need_wh, err;
	aufs_bindex_t bstart;
	struct super_block *sb;

	sb = dentry->d_sb;
	bstart = au_dbstart(dentry);
	if (*bcpup < 0) {
		*bcpup = bstart;
		if (au_test_ro(sb, bstart, dentry->d_inode)) {
			err = AuWbrCopyup(au_sbi(sb), dentry);
			*bcpup = err;
			if (unlikely(err < 0))
				goto out;
		}
	} else
		AuDebugOn(bstart < *bcpup
			  || au_test_ro(sb, *bcpup, dentry->d_inode));
	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);

	if (*bcpup != bstart) {
		err = au_cpup_dirs(dentry, *bcpup);
		if (unlikely(err))
			goto out;
		need_wh = 1;
	} else {
		aufs_bindex_t old_bend, new_bend, bdiropq = -1;

		old_bend = au_dbend(dentry);
		if (isdir) {
			bdiropq = au_dbdiropq(dentry);
			au_set_dbdiropq(dentry, -1);
		}
		need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
					 /*nd*/NULL);
		err = need_wh;
		if (isdir)
			au_set_dbdiropq(dentry, bdiropq);
		if (unlikely(err < 0))
			goto out;
		new_bend = au_dbend(dentry);
		if (!need_wh && old_bend != new_bend) {
			au_set_h_dptr(dentry, new_bend, NULL);
			au_set_dbend(dentry, old_bend);
		}
	}
	AuDbg("need_wh %d\n", need_wh);
	err = need_wh;

out:
	return err;
}
Exemple #2
0
/*
 * decide if a new whiteout for @dentry is necessary or not.
 * when it is necessary, prepare the parent dir for the upper branch whose
 * branch index is @bcpup for creation. the actual creation of the whiteout will
 * be done by caller.
 * return value:
 * 0: wh is unnecessary
 * plus: wh is necessary
 * minus: error
 */
int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
{
	int need_wh, err;
	aufs_bindex_t bstart;
	struct super_block *sb;

	sb = dentry->d_sb;
	bstart = au_dbstart(dentry);
	if (*bcpup < 0) {
		*bcpup = bstart;
		if (au_test_ro(sb, bstart, dentry->d_inode)) {
			err = AuWbrCopyup(au_sbi(sb), dentry);
			*bcpup = err;
			if (unlikely(err < 0))
				goto out;
		}
	} else
		AuDebugOn(bstart < *bcpup
			  || au_test_ro(sb, *bcpup, dentry->d_inode));
	AuDbg("bcpup %d, bstart %d\n", *bcpup, bstart);

	if (*bcpup != bstart) {
		err = au_cpup_dirs(dentry, *bcpup);
		if (unlikely(err))
			goto out;
		need_wh = 1;
	} else {
		struct au_dinfo *dinfo, *tmp;

		need_wh = -ENOMEM;
		dinfo = au_di(dentry);
		tmp = au_di_alloc(sb, AuLsc_DI_TMP);
		if (tmp) {
			au_di_cp(tmp, dinfo);
			au_di_swap(tmp, dinfo);
			/* returns the number of positive dentries */
			need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
						 /*nd*/NULL);
			au_di_swap(tmp, dinfo);
			au_rw_write_unlock(&tmp->di_rwsem);
			au_di_free(tmp);
		}
	}
	AuDbg("need_wh %d\n", need_wh);
	err = need_wh;

out:
	return err;
}
Exemple #3
0
static int au_wr_dir_cpup(struct dentry *dentry, struct dentry *parent,
			  const unsigned char add_entry, aufs_bindex_t bcpup,
			  aufs_bindex_t bstart)
{
	int err;
	struct dentry *h_parent;
	struct inode *h_dir;

	if (add_entry)
		IMustLock(parent->d_inode);
	else
		di_write_lock_parent(parent);

	err = 0;
	if (!au_h_dptr(parent, bcpup)) {
		if (bstart < bcpup)
			err = au_cpdown_dirs(dentry, bcpup);
		else
			err = au_cpup_dirs(dentry, bcpup);
	}
	if (!err && add_entry) {
		h_parent = au_h_dptr(parent, bcpup);
		h_dir = h_parent->d_inode;
		mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
		err = au_lkup_neg(dentry, bcpup);
		/* todo: no unlock here */
		mutex_unlock(&h_dir->i_mutex);

		AuDbg("bcpup %d\n", bcpup);
		if (!err) {
			if (!dentry->d_inode)
				au_set_h_dptr(dentry, bstart, NULL);
			au_update_dbrange(dentry, /*do_put_zero*/0);
		}
	}

	if (!add_entry)
		di_write_unlock(parent);
	if (!err)
		err = bcpup; /* success */

	AuTraceErr(err);
	return err;
}
Exemple #4
0
/*
 * prepare the @file for writing.
 */
int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
{
	int err;
	aufs_bindex_t bstart, bcpup, dbstart;
	struct dentry *dentry, *parent, *h_dentry;
	struct inode *h_inode, *inode;
	struct super_block *sb;
	struct file *h_file;

	dentry = file->f_dentry;
	sb = dentry->d_sb;
	inode = dentry->d_inode;
	AuDebugOn(au_special_file(inode->i_mode));
	bstart = au_fbstart(file);
	err = au_test_ro(sb, bstart, inode);
	if (!err && (au_hf_top(file)->f_mode & FMODE_WRITE)) {
		err = au_pin(pin, dentry, bstart, AuOpt_UDBA_NONE, /*flags*/0);
		goto out;
	}

	/* need to cpup or reopen */
	parent = dget_parent(dentry);
	di_write_lock_parent(parent);
	err = AuWbrCopyup(au_sbi(sb), dentry);
	bcpup = err;
	if (unlikely(err < 0))
		goto out_dgrade;
	err = 0;

	if (!d_unhashed(dentry) && !au_h_dptr(parent, bcpup)) {
		err = au_cpup_dirs(dentry, bcpup);
		if (unlikely(err))
			goto out_dgrade;
	}

	err = au_pin(pin, dentry, bcpup, AuOpt_UDBA_NONE,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	if (unlikely(err))
		goto out_dgrade;

	h_dentry = au_hf_top(file)->f_dentry;
	h_inode = h_dentry->d_inode;
	dbstart = au_dbstart(dentry);
	if (dbstart <= bcpup) {
		h_dentry = au_h_dptr(dentry, bcpup);
		AuDebugOn(!h_dentry);
		h_inode = h_dentry->d_inode;
		AuDebugOn(!h_inode);
		bstart = bcpup;
	}

	if (dbstart <= bcpup		/* just reopen */
	    || !d_unhashed(dentry)	/* copyup and reopen */
		) {
		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
		h_file = au_h_open_pre(dentry, bstart);
		if (IS_ERR(h_file)) {
			err = PTR_ERR(h_file);
			h_file = NULL;
		} else {
			di_downgrade_lock(parent, AuLock_IR);
			if (dbstart > bcpup)
				err = au_sio_cpup_simple(dentry, bcpup, len,
							 AuCpup_DTIME);
			if (!err)
				err = au_reopen_nondir(file);
		}
		mutex_unlock(&h_inode->i_mutex);
		au_h_open_post(dentry, bstart, h_file);
	} else {			/* copyup as wh and reopen */
		/*
		 * since writable hfsplus branch is not supported,
		 * h_open_pre/post() are unnecessary.
		 */
		mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
		err = au_ready_to_write_wh(file, len, bcpup);
		di_downgrade_lock(parent, AuLock_IR);
		mutex_unlock(&h_inode->i_mutex);
	}

	if (!err) {
		au_pin_set_parent_lflag(pin, /*lflag*/0);
		goto out_dput; /* success */
	}
	au_unpin(pin);
	goto out_unlock;

out_dgrade:
	di_downgrade_lock(parent, AuLock_IR);
out_unlock:
	di_read_unlock(parent, AuLock_IR);
out_dput:
	dput(parent);
out:
	return err;
}
int aufs_rename(struct inode *_src_dir, struct dentry *_src_dentry,
		struct inode *_dst_dir, struct dentry *_dst_dentry)
{
	int err, flags;
	/* reduce stack space */
	struct au_ren_args *a;

	AuDbg("%.*s, %.*s\n", AuDLNPair(_src_dentry), AuDLNPair(_dst_dentry));
	IMustLock(_src_dir);
	IMustLock(_dst_dir);

	err = -ENOMEM;
	BUILD_BUG_ON(sizeof(*a) > PAGE_SIZE);
	a = kzalloc(sizeof(*a), GFP_NOFS);
	if (unlikely(!a))
		goto out;

	a->src_dir = _src_dir;
	a->src_dentry = _src_dentry;
	a->src_inode = a->src_dentry->d_inode;
	a->src_parent = a->src_dentry->d_parent; /* dir inode is locked */
	a->dst_dir = _dst_dir;
	a->dst_dentry = _dst_dentry;
	a->dst_inode = a->dst_dentry->d_inode;
	a->dst_parent = a->dst_dentry->d_parent; /* dir inode is locked */
	if (a->dst_inode) {
		IMustLock(a->dst_inode);
		au_igrab(a->dst_inode);
	}

	err = -ENOTDIR;
	flags = AuLock_FLUSH | AuLock_NOPLM | AuLock_GEN;
	if (S_ISDIR(a->src_inode->i_mode)) {
		au_fset_ren(a->flags, ISDIR);
		if (unlikely(a->dst_inode && !S_ISDIR(a->dst_inode->i_mode)))
			goto out_free;
		err = aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
						AuLock_DIR | flags);
	} else
		err = aufs_read_and_write_lock2(a->dst_dentry, a->src_dentry,
						flags);
	if (unlikely(err))
		goto out_free;

	err = au_d_hashed_positive(a->src_dentry);
	if (unlikely(err))
		goto out_unlock;
	err = -ENOENT;
	if (a->dst_inode) {
		/*
		 * If it is a dir, VFS unhash dst_dentry before this
		 * function. It means we cannot rely upon d_unhashed().
		 */
		if (unlikely(!a->dst_inode->i_nlink))
			goto out_unlock;
		if (!S_ISDIR(a->dst_inode->i_mode)) {
			err = au_d_hashed_positive(a->dst_dentry);
			if (unlikely(err))
				goto out_unlock;
		} else if (unlikely(IS_DEADDIR(a->dst_inode)))
			goto out_unlock;
	} else if (unlikely(d_unhashed(a->dst_dentry)))
		goto out_unlock;

	au_fset_ren(a->flags, ISSAMEDIR); /* temporary */
	di_write_lock_parent(a->dst_parent);

	/* which branch we process */
	err = au_ren_wbr(a);
	if (unlikely(err < 0))
		goto out_parent;
	a->br = au_sbr(a->dst_dentry->d_sb, a->btgt);
	a->h_path.mnt = a->br->br_mnt;

	/* are they available to be renamed */
	err = au_ren_may_dir(a);
	if (unlikely(err))
		goto out_children;

	/* prepare the writable parent dir on the same branch */
	if (a->dst_bstart == a->btgt) {
		au_fset_ren(a->flags, WHDST);
	} else {
		err = au_cpup_dirs(a->dst_dentry, a->btgt);
		if (unlikely(err))
			goto out_children;
	}

	if (a->src_dir != a->dst_dir) {
		/*
		 * this temporary unlock is safe,
		 * because both dir->i_mutex are locked.
		 */
		di_write_unlock(a->dst_parent);
		di_write_lock_parent(a->src_parent);
		err = au_wr_dir_need_wh(a->src_dentry,
					au_ftest_ren(a->flags, ISDIR),
					&a->btgt);
		di_write_unlock(a->src_parent);
		di_write_lock2_parent(a->src_parent, a->dst_parent, /*isdir*/1);
		au_fclr_ren(a->flags, ISSAMEDIR);
	} else
		err = au_wr_dir_need_wh(a->src_dentry,
					au_ftest_ren(a->flags, ISDIR),
					&a->btgt);
	if (unlikely(err < 0))
		goto out_children;
	if (err)
		au_fset_ren(a->flags, WHSRC);

	/* lock them all */
	err = au_ren_lock(a);
	if (unlikely(err))
		goto out_children;

	if (!au_opt_test(au_mntflags(a->dst_dir->i_sb), UDBA_NONE))
		err = au_may_ren(a);
	else if (unlikely(a->dst_dentry->d_name.len > AUFS_MAX_NAMELEN))
		err = -ENAMETOOLONG;
	if (unlikely(err))
		goto out_hdir;

	/* store timestamps to be revertible */
	au_ren_dt(a);

	/* here we go */
	err = do_rename(a);
	if (unlikely(err))
		goto out_dt;

	/* update dir attributes */
	au_ren_refresh_dir(a);

	/* dput/iput all lower dentries */
	au_ren_refresh(a);

	goto out_hdir; /* success */

out_dt:
	au_ren_rev_dt(err, a);
out_hdir:
	au_ren_unlock(a);
out_children:
	au_nhash_wh_free(&a->whlist);
	if (err && a->dst_inode && a->dst_bstart != a->btgt) {
		AuDbg("bstart %d, btgt %d\n", a->dst_bstart, a->btgt);
		au_set_h_dptr(a->dst_dentry, a->btgt, NULL);
		au_set_dbstart(a->dst_dentry, a->dst_bstart);
	}
out_parent:
	if (!err)
		d_move(a->src_dentry, a->dst_dentry);
	else {
		au_update_dbstart(a->dst_dentry);
		if (!a->dst_inode)
			d_drop(a->dst_dentry);
	}
	if (au_ftest_ren(a->flags, ISSAMEDIR))
		di_write_unlock(a->dst_parent);
	else
		di_write_unlock2(a->src_parent, a->dst_parent);
out_unlock:
	aufs_read_and_write_unlock2(a->dst_dentry, a->src_dentry);
out_free:
	iput(a->dst_inode);
	if (a->thargs)
		au_whtmp_rmdir_free(a->thargs);
	kfree(a);
out:
	AuTraceErr(err);
	return err;
}
Exemple #6
0
/*
 * prepare the @file for writing.
 */
int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
{
	int err;
	aufs_bindex_t bstart, bcpup;
	struct dentry *dentry, *parent, *h_dentry;
	struct inode *h_inode, *inode;
	struct super_block *sb;

	dentry = file->f_dentry;
	sb = dentry->d_sb;
	inode = dentry->d_inode;
	AuDebugOn(au_special_file(inode->i_mode));
	bstart = au_fbstart(file);
	err = au_test_ro(sb, bstart, inode);
	if (!err && (au_h_fptr(file, bstart)->f_mode & FMODE_WRITE)) {
		err = au_pin(pin, dentry, bstart, AuOpt_UDBA_NONE, /*flags*/0);
		goto out;
	}

	/* need to cpup */
	parent = dget_parent(dentry);
	di_write_lock_parent(parent);
	err = AuWbrCopyup(au_sbi(sb), dentry);
	bcpup = err;
	if (unlikely(err < 0))
		goto out_dgrade;
	err = 0;

	if (!au_h_dptr(parent, bcpup)) {
		err = au_cpup_dirs(dentry, bcpup);
		if (unlikely(err))
			goto out_dgrade;
	}

	err = au_pin(pin, dentry, bcpup, AuOpt_UDBA_NONE,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	if (unlikely(err))
		goto out_dgrade;

	h_dentry = au_h_fptr(file, bstart)->f_dentry;
	h_inode = h_dentry->d_inode;
	mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
	if (d_unhashed(dentry) /* || d_unhashed(h_dentry) */
	    /* || !h_inode->i_nlink */) {
		err = au_ready_to_write_wh(file, len, bcpup);
		di_downgrade_lock(parent, AuLock_IR);
	} else {
		di_downgrade_lock(parent, AuLock_IR);
		if (!au_h_dptr(dentry, bcpup))
			err = au_sio_cpup_simple(dentry, bcpup, len,
						 AuCpup_DTIME);
		if (!err)
			err = au_reopen_nondir(file);
	}
	mutex_unlock(&h_inode->i_mutex);

	if (!err) {
		au_pin_set_parent_lflag(pin, /*lflag*/0);
		goto out_dput; /* success */
	}
	au_unpin(pin);
	goto out_unlock;

 out_dgrade:
	di_downgrade_lock(parent, AuLock_IR);
 out_unlock:
	di_read_unlock(parent, AuLock_IR);
 out_dput:
	dput(parent);
 out:
	return err;
}
Exemple #7
0
static int au_ready_to_write_wh(struct file *file, loff_t len,
				aufs_bindex_t bcpup, struct au_pin *pin)
{
	int err;
	struct inode *inode, *h_inode;
	struct dentry *h_dentry, *hi_wh;
	struct au_cp_generic cpg = {
		.dentry	= file->f_dentry,
		.bdst	= bcpup,
		.bsrc	= -1,
		.len	= len,
		.pin	= pin
	};

	au_update_dbstart(cpg.dentry);
	inode = cpg.dentry->d_inode;
	h_inode = NULL;
	if (au_dbstart(cpg.dentry) <= bcpup
	    && au_dbend(cpg.dentry) >= bcpup) {
		h_dentry = au_h_dptr(cpg.dentry, bcpup);
		if (h_dentry)
			h_inode = h_dentry->d_inode;
	}
	hi_wh = au_hi_wh(inode, bcpup);
	if (!hi_wh && !h_inode)
		err = au_sio_cpup_wh(&cpg, file);
	else
		/* already copied-up after unlink */
		err = au_reopen_wh(file, bcpup, hi_wh);

	if (!err
	    && inode->i_nlink > 1
	    && au_opt_test(au_mntflags(cpg.dentry->d_sb), PLINK))
		au_plink_append(inode, bcpup, au_h_dptr(cpg.dentry, bcpup));

	return err;
}

/*
 * prepare the @file for writing.
 */
int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
{
	int err;
	aufs_bindex_t dbstart;
	struct dentry *parent, *h_dentry;
	struct inode *inode;
	struct super_block *sb;
	struct file *h_file;
	struct au_cp_generic cpg = {
		.dentry	= file->f_dentry,
		.bdst	= -1,
		.bsrc	= -1,
		.len	= len,
		.pin	= pin,
		.flags	= AuCpup_DTIME
	};

	sb = cpg.dentry->d_sb;
	inode = cpg.dentry->d_inode;
	AuDebugOn(au_special_file(inode->i_mode));
	cpg.bsrc = au_fbstart(file);
	err = au_test_ro(sb, cpg.bsrc, inode);
	if (!err && (au_hf_top(file)->f_mode & FMODE_WRITE)) {
		err = au_pin(pin, cpg.dentry, cpg.bsrc, AuOpt_UDBA_NONE,
			     /*flags*/0);
		goto out;
	}

	/* need to cpup or reopen */
	parent = dget_parent(cpg.dentry);
	di_write_lock_parent(parent);
	err = AuWbrCopyup(au_sbi(sb), cpg.dentry);
	cpg.bdst = err;
	if (unlikely(err < 0))
		goto out_dgrade;
	err = 0;

	if (!d_unhashed(cpg.dentry) && !au_h_dptr(parent, cpg.bdst)) {
		err = au_cpup_dirs(cpg.dentry, cpg.bdst);
		if (unlikely(err))
			goto out_dgrade;
	}

	err = au_pin(pin, cpg.dentry, cpg.bdst, AuOpt_UDBA_NONE,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	if (unlikely(err))
		goto out_dgrade;

	h_dentry = au_hf_top(file)->f_dentry;
	dbstart = au_dbstart(cpg.dentry);
	if (dbstart <= cpg.bdst) {
		h_dentry = au_h_dptr(cpg.dentry, cpg.bdst);
		AuDebugOn(!h_dentry);
		cpg.bsrc = cpg.bdst;
	}

	if (dbstart <= cpg.bdst		/* just reopen */
	    || !d_unhashed(cpg.dentry)	/* copyup and reopen */
		) {
		h_file = au_h_open_pre(cpg.dentry, cpg.bsrc, /*force_wr*/0);
		if (IS_ERR(h_file))
			err = PTR_ERR(h_file);
		else {
			di_downgrade_lock(parent, AuLock_IR);
			if (dbstart > cpg.bdst)
				err = au_sio_cpup_simple(&cpg);
			if (!err)
				err = au_reopen_nondir(file);
			au_h_open_post(cpg.dentry, cpg.bsrc, h_file);
		}
	} else {			/* copyup as wh and reopen */
		/*
		 * since writable hfsplus branch is not supported,
		 * h_open_pre/post() are unnecessary.
		 */
		err = au_ready_to_write_wh(file, len, cpg.bdst, pin);
		di_downgrade_lock(parent, AuLock_IR);
	}

	if (!err) {
		au_pin_set_parent_lflag(pin, /*lflag*/0);
		goto out_dput; /* success */
	}
	au_unpin(pin);
	goto out_unlock;

out_dgrade:
	di_downgrade_lock(parent, AuLock_IR);
out_unlock:
	di_read_unlock(parent, AuLock_IR);
out_dput:
	dput(parent);
out:
	return err;
}

/* ---------------------------------------------------------------------- */

int au_do_flush(struct file *file, fl_owner_t id,
		int (*flush)(struct file *file, fl_owner_t id))
{
	int err;
	struct super_block *sb;
	struct inode *inode;

	inode = file_inode(file);
	sb = inode->i_sb;
	si_noflush_read_lock(sb);
	fi_read_lock(file);
	ii_read_lock_child(inode);

	err = flush(file, id);
	au_cpup_attr_timesizes(inode);

	ii_read_unlock(inode);
	fi_read_unlock(file);
	si_read_unlock(sb);
	return err;
}
Exemple #8
0
static int au_cmoo(struct dentry *dentry)
{
	int err, cmoo;
	unsigned int udba;
	struct path h_path;
	struct au_pin pin;
	struct au_cp_generic cpg = {
		.dentry	= dentry,
		.bdst	= -1,
		.bsrc	= -1,
		.len	= -1,
		.pin	= &pin,
		.flags	= AuCpup_DTIME | AuCpup_HOPEN
	};
	struct inode *inode, *delegated;
	struct super_block *sb;
	struct au_sbinfo *sbinfo;
	struct au_fhsm *fhsm;
	pid_t pid;
	struct au_branch *br;
	struct dentry *parent;
	struct au_hinode *hdir;

	DiMustWriteLock(dentry);
	inode = dentry->d_inode;
	IiMustWriteLock(inode);

	err = 0;
	if (IS_ROOT(dentry))
		goto out;
	cpg.bsrc = au_dbstart(dentry);
	if (!cpg.bsrc)
		goto out;

	sb = dentry->d_sb;
	sbinfo = au_sbi(sb);
	fhsm = &sbinfo->si_fhsm;
	pid = au_fhsm_pid(fhsm);
	if (pid
	    && (current->pid == pid
		|| current->real_parent->pid == pid))
		goto out;

	br = au_sbr(sb, cpg.bsrc);
	cmoo = au_br_cmoo(br->br_perm);
	if (!cmoo)
		goto out;
	if (!S_ISREG(inode->i_mode))
		cmoo &= AuBrAttr_COO_ALL;
	if (!cmoo)
		goto out;

	parent = dget_parent(dentry);
	di_write_lock_parent(parent);
	err = au_wbr_do_copyup_bu(dentry, cpg.bsrc - 1);
	cpg.bdst = err;
	if (unlikely(err < 0)) {
		err = 0;	/* there is no upper writable branch */
		goto out_dgrade;
	}
	AuDbg("bsrc %d, bdst %d\n", cpg.bsrc, cpg.bdst);

	/* do not respect the coo attrib for the target branch */
	err = au_cpup_dirs(dentry, cpg.bdst);
	if (unlikely(err))
		goto out_dgrade;

	di_downgrade_lock(parent, AuLock_IR);
	udba = au_opt_udba(sb);
	err = au_pin(&pin, dentry, cpg.bdst, udba,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	if (unlikely(err))
		goto out_parent;

	err = au_sio_cpup_simple(&cpg);
	au_unpin(&pin);
	if (unlikely(err))
		goto out_parent;
	if (!(cmoo & AuBrWAttr_MOO))
		goto out_parent; /* success */

	err = au_pin(&pin, dentry, cpg.bsrc, udba,
		     AuPin_DI_LOCKED | AuPin_MNT_WRITE);
	if (unlikely(err))
		goto out_parent;

	h_path.mnt = au_br_mnt(br);
	h_path.dentry = au_h_dptr(dentry, cpg.bsrc);
	hdir = au_hi(parent->d_inode, cpg.bsrc);
	delegated = NULL;
	err = vfsub_unlink(hdir->hi_inode, &h_path, &delegated, /*force*/1);
	au_unpin(&pin);
	/* todo: keep h_dentry or not? */
	if (unlikely(err == -EWOULDBLOCK)) {
		pr_warn("cannot retry for NFSv4 delegation"
			" for an internal unlink\n");
		iput(delegated);
	}
	if (unlikely(err)) {
		pr_err("unlink %pd after coo failed (%d), ignored\n",
		       dentry, err);
		err = 0;
	}
	goto out_parent; /* success */

out_dgrade:
	di_downgrade_lock(parent, AuLock_IR);
out_parent:
	di_read_unlock(parent, AuLock_IR);
	dput(parent);
out:
	AuTraceErr(err);
	return err;
}

int au_do_open(struct file *file, int (*open)(struct file *file, int flags),
	       struct au_fidir *fidir)
{
	int err;
	struct dentry *dentry;
	struct au_finfo *finfo;

	err = au_finfo_init(file, fidir);
	if (unlikely(err))
		goto out;

	dentry = file->f_path.dentry;
	di_write_lock_child(dentry);
	err = au_cmoo(dentry);
	di_downgrade_lock(dentry, AuLock_IR);
	if (!err)
		err = open(file, vfsub_file_flags(file));
	di_read_unlock(dentry, AuLock_IR);

	finfo = au_fi(file);
	if (!err) {
		finfo->fi_file = file;
		au_sphl_add(&finfo->fi_hlist,
			    &au_sbi(file->f_path.dentry->d_sb)->si_files);
	}
	fi_write_unlock(file);
	if (unlikely(err)) {
		finfo->fi_hdir = NULL;
		au_finfo_fin(file);
	}

out:
	return err;
}