Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 1095 insertions, 0 deletions

diff --git a/fs/hpfs/dnode.c b/fs/hpfs/dnode.c
new file mode 100644
index 000000000..8c6aa060f
--- /dev/null
+++ b/fs/hpfs/dnode.c
@@ -0,0 +1,1095 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/hpfs/dnode.c
+ *
+ *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
+ *
+ *  handling directory dnode tree - adding, deleteing & searching for dirents
+ */
+
+#include "hpfs_fn.h"
+
+static loff_t get_pos(struct dnode *d, struct hpfs_dirent *fde)
+{
+	struct hpfs_dirent *de;
+	struct hpfs_dirent *de_end = dnode_end_de(d);
+	int i = 1;
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de)) {
+		if (de == fde) return ((loff_t) le32_to_cpu(d->self) << 4) | (loff_t)i;
+		i++;
+	}
+	pr_info("%s(): not_found\n", __func__);
+	return ((loff_t)le32_to_cpu(d->self) << 4) | (loff_t)1;
+}
+
+int hpfs_add_pos(struct inode *inode, loff_t *pos)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
+	int i = 0;
+	loff_t **ppos;
+
+	if (hpfs_inode->i_rddir_off)
+		for (; hpfs_inode->i_rddir_off[i]; i++)
+			if (hpfs_inode->i_rddir_off[i] == pos)
+				return 0;
+	if (!(i&0x0f)) {
+		ppos = kmalloc_objs(loff_t *, i + 0x11, GFP_NOFS);
+		if (!ppos) {
+			pr_err("out of memory for position list\n");
+			return -ENOMEM;
+		}
+		if (hpfs_inode->i_rddir_off) {
+			memcpy(ppos, hpfs_inode->i_rddir_off, i * sizeof(loff_t));
+			kfree(hpfs_inode->i_rddir_off);
+		}
+		hpfs_inode->i_rddir_off = ppos;
+	}
+	hpfs_inode->i_rddir_off[i] = pos;
+	hpfs_inode->i_rddir_off[i + 1] = NULL;
+	return 0;
+}
+
+void hpfs_del_pos(struct inode *inode, loff_t *pos)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
+	loff_t **i, **j;
+
+	if (!hpfs_inode->i_rddir_off) goto not_f;
+	for (i = hpfs_inode->i_rddir_off; *i; i++) if (*i == pos) goto fnd;
+	goto not_f;
+	fnd:
+	for (j = i + 1; *j; j++) ;
+	*i = *(j - 1);
+	*(j - 1) = NULL;
+	if (j - 1 == hpfs_inode->i_rddir_off) {
+		kfree(hpfs_inode->i_rddir_off);
+		hpfs_inode->i_rddir_off = NULL;
+	}
+	return;
+	not_f:
+	/*pr_warn("position pointer %p->%08x not found\n",
+		  pos, (int)*pos);*/
+	return;
+}
+
+static void for_all_poss(struct inode *inode, void (*f)(loff_t *, loff_t, loff_t),
+			 loff_t p1, loff_t p2)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(inode);
+	loff_t **i;
+
+	if (!hpfs_inode->i_rddir_off) return;
+	for (i = hpfs_inode->i_rddir_off; *i; i++) (*f)(*i, p1, p2);
+	return;
+}
+
+static void hpfs_pos_subst(loff_t *p, loff_t f, loff_t t)
+{
+	if (*p == f) *p = t;
+}
+
+/*void hpfs_hpfs_pos_substd(loff_t *p, loff_t f, loff_t t)
+{
+	if ((*p & ~0x3f) == (f & ~0x3f)) *p = (t & ~0x3f) | (*p & 0x3f);
+}*/
+
+static void hpfs_pos_ins(loff_t *p, loff_t d, loff_t c)
+{
+	if ((*p & ~0x3f) == (d & ~0x3f) && (*p & 0x3f) >= (d & 0x3f)) {
+		int n = (*p & 0x3f) + c;
+		if (n > 0x3f)
+			pr_err("%s(): %08x + %d\n",
+				__func__, (int)*p, (int)c >> 8);
+		else
+			*p = (*p & ~0x3f) | n;
+	}
+}
+
+static void hpfs_pos_del(loff_t *p, loff_t d, loff_t c)
+{
+	if ((*p & ~0x3f) == (d & ~0x3f) && (*p & 0x3f) >= (d & 0x3f)) {
+		int n = (*p & 0x3f) - c;
+		if (n < 1)
+			pr_err("%s(): %08x - %d\n",
+				__func__, (int)*p, (int)c >> 8);
+		else
+			*p = (*p & ~0x3f) | n;
+	}
+}
+
+static struct hpfs_dirent *dnode_pre_last_de(struct dnode *d)
+{
+	struct hpfs_dirent *de, *de_end, *dee = NULL, *deee = NULL;
+	de_end = dnode_end_de(d);
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de)) {
+		deee = dee; dee = de;
+	}	
+	return deee;
+}
+
+static struct hpfs_dirent *dnode_last_de(struct dnode *d)
+{
+	struct hpfs_dirent *de, *de_end, *dee = NULL;
+	de_end = dnode_end_de(d);
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de)) {
+		dee = de;
+	}	
+	return dee;
+}
+
+static void set_last_pointer(struct super_block *s, struct dnode *d, dnode_secno ptr)
+{
+	struct hpfs_dirent *de;
+	if (!(de = dnode_last_de(d))) {
+		hpfs_error(s, "set_last_pointer: empty dnode %08x", le32_to_cpu(d->self));
+		return;
+	}
+	if (hpfs_sb(s)->sb_chk) {
+		if (de->down) {
+			hpfs_error(s, "set_last_pointer: dnode %08x has already last pointer %08x",
+				le32_to_cpu(d->self), de_down_pointer(de));
+			return;
+		}
+		if (le16_to_cpu(de->length) != 32) {
+			hpfs_error(s, "set_last_pointer: bad last dirent in dnode %08x", le32_to_cpu(d->self));
+			return;
+		}
+	}
+	if (ptr) {
+		le32_add_cpu(&d->first_free, 4);
+		if (le32_to_cpu(d->first_free) > 2048) {
+			hpfs_error(s, "set_last_pointer: too long dnode %08x", le32_to_cpu(d->self));
+			le32_add_cpu(&d->first_free, -4);
+			return;
+		}
+		de->length = cpu_to_le16(36);
+		de->down = 1;
+		*(__le32 *)((char *)de + 32) = cpu_to_le32(ptr);
+	}
+}
+
+/* Add an entry to dnode and don't care if it grows over 2048 bytes */
+
+struct hpfs_dirent *hpfs_add_de(struct super_block *s, struct dnode *d,
+				const unsigned char *name,
+				unsigned namelen, secno down_ptr)
+{
+	struct hpfs_dirent *de;
+	struct hpfs_dirent *de_end = dnode_end_de(d);
+	unsigned d_size = de_size(namelen, down_ptr);
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de)) {
+		int c = hpfs_compare_names(s, name, namelen, de->name, de->namelen, de->last);
+		if (!c) {
+			hpfs_error(s, "name (%c,%d) already exists in dnode %08x", *name, namelen, le32_to_cpu(d->self));
+			return NULL;
+		}
+		if (c < 0) break;
+	}
+	memmove((char *)de + d_size, de, (char *)de_end - (char *)de);
+	memset(de, 0, d_size);
+	if (down_ptr) {
+		*(__le32 *)((char *)de + d_size - 4) = cpu_to_le32(down_ptr);
+		de->down = 1;
+	}
+	de->length = cpu_to_le16(d_size);
+	de->not_8x3 = hpfs_is_name_long(name, namelen);
+	de->namelen = namelen;
+	memcpy(de->name, name, namelen);
+	le32_add_cpu(&d->first_free, d_size);
+	return de;
+}
+
+/* Delete dirent and don't care about its subtree */
+
+static void hpfs_delete_de(struct super_block *s, struct dnode *d,
+			   struct hpfs_dirent *de)
+{
+	if (de->last) {
+		hpfs_error(s, "attempt to delete last dirent in dnode %08x", le32_to_cpu(d->self));
+		return;
+	}
+	d->first_free = cpu_to_le32(le32_to_cpu(d->first_free) - le16_to_cpu(de->length));
+	memmove(de, de_next_de(de), le32_to_cpu(d->first_free) + (char *)d - (char *)de);
+}
+
+static void fix_up_ptrs(struct super_block *s, struct dnode *d)
+{
+	struct hpfs_dirent *de;
+	struct hpfs_dirent *de_end = dnode_end_de(d);
+	dnode_secno dno = le32_to_cpu(d->self);
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de))
+		if (de->down) {
+			struct quad_buffer_head qbh;
+			struct dnode *dd;
+			if ((dd = hpfs_map_dnode(s, de_down_pointer(de), &qbh))) {
+				if (le32_to_cpu(dd->up) != dno || dd->root_dnode) {
+					dd->up = cpu_to_le32(dno);
+					dd->root_dnode = 0;
+					hpfs_mark_4buffers_dirty(&qbh);
+				}
+				hpfs_brelse4(&qbh);
+			}
+		}
+}
+
+/* Add an entry to dnode and do dnode splitting if required */
+
+static int hpfs_add_to_dnode(struct inode *i, dnode_secno dno,
+			     const unsigned char *name, unsigned namelen,
+			     struct hpfs_dirent *new_de, dnode_secno down_ptr)
+{
+	struct quad_buffer_head qbh, qbh1, qbh2;
+	struct dnode *d, *ad, *rd, *nd = NULL;
+	dnode_secno adno, rdno;
+	struct hpfs_dirent *de;
+	struct hpfs_dirent nde;
+	unsigned char *nname;
+	int h;
+	int pos;
+	struct buffer_head *bh;
+	struct fnode *fnode;
+	int c1, c2 = 0;
+	if (!(nname = kmalloc(256, GFP_NOFS))) {
+		pr_err("out of memory, can't add to dnode\n");
+		return 1;
+	}
+	go_up:
+	if (namelen >= 256) {
+		hpfs_error(i->i_sb, "%s(): namelen == %d", __func__, namelen);
+		kfree(nd);
+		kfree(nname);
+		return 1;
+	}
+	if (!(d = hpfs_map_dnode(i->i_sb, dno, &qbh))) {
+		kfree(nd);
+		kfree(nname);
+		return 1;
+	}
+	go_up_a:
+	if (hpfs_sb(i->i_sb)->sb_chk)
+		if (hpfs_stop_cycles(i->i_sb, dno, &c1, &c2, "hpfs_add_to_dnode")) {
+			hpfs_brelse4(&qbh);
+			kfree(nd);
+			kfree(nname);
+			return 1;
+		}
+	if (le32_to_cpu(d->first_free) + de_size(namelen, down_ptr) <= 2048) {
+		loff_t t;
+		copy_de(de=hpfs_add_de(i->i_sb, d, name, namelen, down_ptr), new_de);
+		t = get_pos(d, de);
+		for_all_poss(i, hpfs_pos_ins, t, 1);
+		for_all_poss(i, hpfs_pos_subst, 4, t);
+		for_all_poss(i, hpfs_pos_subst, 5, t + 1);
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		kfree(nd);
+		kfree(nname);
+		return 0;
+	}
+	if (!nd) if (!(nd = kmalloc(0x924, GFP_NOFS))) {
+		/* 0x924 is a max size of dnode after adding a dirent with
+		   max name length. We alloc this only once. There must
+		   not be any error while splitting dnodes, otherwise the
+		   whole directory, not only file we're adding, would
+		   be lost. */
+		pr_err("out of memory for dnode splitting\n");
+		hpfs_brelse4(&qbh);
+		kfree(nname);
+		return 1;
+	}	
+	memcpy(nd, d, le32_to_cpu(d->first_free));
+	copy_de(de = hpfs_add_de(i->i_sb, nd, name, namelen, down_ptr), new_de);
+	for_all_poss(i, hpfs_pos_ins, get_pos(nd, de), 1);
+	h = ((char *)dnode_last_de(nd) - (char *)nd) / 2 + 10;
+	if (!(ad = hpfs_alloc_dnode(i->i_sb, le32_to_cpu(d->up), &adno, &qbh1))) {
+		hpfs_error(i->i_sb, "unable to alloc dnode - dnode tree will be corrupted");
+		hpfs_brelse4(&qbh);
+		kfree(nd);
+		kfree(nname);
+		return 1;
+	}
+	i->i_size += 2048;
+	i->i_blocks += 4;
+	pos = 1;
+	for (de = dnode_first_de(nd); (char *)de_next_de(de) - (char *)nd < h; de = de_next_de(de)) {
+		copy_de(hpfs_add_de(i->i_sb, ad, de->name, de->namelen, de->down ? de_down_pointer(de) : 0), de);
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)dno << 4) | pos, ((loff_t)adno << 4) | pos);
+		pos++;
+	}
+	copy_de(new_de = &nde, de);
+	memcpy(nname, de->name, de->namelen);
+	name = nname;
+	namelen = de->namelen;
+	for_all_poss(i, hpfs_pos_subst, ((loff_t)dno << 4) | pos, 4);
+	down_ptr = adno;
+	set_last_pointer(i->i_sb, ad, de->down ? de_down_pointer(de) : 0);
+	de = de_next_de(de);
+	memmove((char *)nd + 20, de, le32_to_cpu(nd->first_free) + (char *)nd - (char *)de);
+	le32_add_cpu(&nd->first_free, -((char *)de - (char *)nd - 20));
+	memcpy(d, nd, le32_to_cpu(nd->first_free));
+	for_all_poss(i, hpfs_pos_del, (loff_t)dno << 4, pos);
+	fix_up_ptrs(i->i_sb, ad);
+	if (!d->root_dnode) {
+		ad->up = d->up;
+		dno = le32_to_cpu(ad->up);
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		hpfs_mark_4buffers_dirty(&qbh1);
+		hpfs_brelse4(&qbh1);
+		goto go_up;
+	}
+	if (!(rd = hpfs_alloc_dnode(i->i_sb, le32_to_cpu(d->up), &rdno, &qbh2))) {
+		hpfs_error(i->i_sb, "unable to alloc dnode - dnode tree will be corrupted");
+		hpfs_brelse4(&qbh);
+		hpfs_brelse4(&qbh1);
+		kfree(nd);
+		kfree(nname);
+		return 1;
+	}
+	i->i_size += 2048;
+	i->i_blocks += 4;
+	rd->root_dnode = 1;
+	rd->up = d->up;
+	if (!(fnode = hpfs_map_fnode(i->i_sb, le32_to_cpu(d->up), &bh))) {
+		hpfs_free_dnode(i->i_sb, rdno);
+		hpfs_brelse4(&qbh);
+		hpfs_brelse4(&qbh1);
+		hpfs_brelse4(&qbh2);
+		kfree(nd);
+		kfree(nname);
+		return 1;
+	}
+	fnode->u.external[0].disk_secno = cpu_to_le32(rdno);
+	mark_buffer_dirty(bh);
+	brelse(bh);
+	hpfs_i(i)->i_dno = rdno;
+	d->up = ad->up = cpu_to_le32(rdno);
+	d->root_dnode = ad->root_dnode = 0;
+	hpfs_mark_4buffers_dirty(&qbh);
+	hpfs_brelse4(&qbh);
+	hpfs_mark_4buffers_dirty(&qbh1);
+	hpfs_brelse4(&qbh1);
+	qbh = qbh2;
+	set_last_pointer(i->i_sb, rd, dno);
+	dno = rdno;
+	d = rd;
+	goto go_up_a;
+}
+
+/*
+ * Add an entry to directory btree.
+ * I hate such crazy directory structure.
+ * It's easy to read but terrible to write.
+ * I wrote this directory code 4 times.
+ * I hope, now it's finally bug-free.
+ */
+
+int hpfs_add_dirent(struct inode *i,
+		    const unsigned char *name, unsigned namelen,
+		    struct hpfs_dirent *new_de)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	struct dnode *d;
+	struct hpfs_dirent *de, *de_end;
+	struct quad_buffer_head qbh;
+	dnode_secno dno;
+	int c;
+	int c1, c2 = 0;
+	dno = hpfs_inode->i_dno;
+	down:
+	if (hpfs_sb(i->i_sb)->sb_chk)
+		if (hpfs_stop_cycles(i->i_sb, dno, &c1, &c2, "hpfs_add_dirent")) return 1;
+	if (!(d = hpfs_map_dnode(i->i_sb, dno, &qbh))) return 1;
+	de_end = dnode_end_de(d);
+	for (de = dnode_first_de(d); de < de_end; de = de_next_de(de)) {
+		if (!(c = hpfs_compare_names(i->i_sb, name, namelen, de->name, de->namelen, de->last))) {
+			hpfs_brelse4(&qbh);
+			return -1;
+		}	
+		if (c < 0) {
+			if (de->down) {
+				dno = de_down_pointer(de);
+				hpfs_brelse4(&qbh);
+				goto down;
+			}
+			break;
+		}
+	}
+	hpfs_brelse4(&qbh);
+	if (hpfs_check_free_dnodes(i->i_sb, FREE_DNODES_ADD)) {
+		c = 1;
+		goto ret;
+	}	
+	c = hpfs_add_to_dnode(i, dno, name, namelen, new_de, 0);
+	ret:
+	return c;
+}
+
+/* 
+ * Find dirent with higher name in 'from' subtree and move it to 'to' dnode.
+ * Return the dnode we moved from (to be checked later if it's empty)
+ */
+
+static secno move_to_top(struct inode *i, dnode_secno from, dnode_secno to)
+{
+	dnode_secno dno, ddno;
+	dnode_secno chk_up = to;
+	struct dnode *dnode;
+	struct quad_buffer_head qbh;
+	struct hpfs_dirent *de, *nde;
+	int a;
+	loff_t t;
+	int c1, c2 = 0;
+	dno = from;
+	while (1) {
+		if (hpfs_sb(i->i_sb)->sb_chk)
+			if (hpfs_stop_cycles(i->i_sb, dno, &c1, &c2, "move_to_top"))
+				return 0;
+		if (!(dnode = hpfs_map_dnode(i->i_sb, dno, &qbh))) return 0;
+		if (hpfs_sb(i->i_sb)->sb_chk) {
+			if (le32_to_cpu(dnode->up) != chk_up) {
+				hpfs_error(i->i_sb, "move_to_top: up pointer from %08x should be %08x, is %08x",
+					dno, chk_up, le32_to_cpu(dnode->up));
+				hpfs_brelse4(&qbh);
+				return 0;
+			}
+			chk_up = dno;
+		}
+		if (!(de = dnode_last_de(dnode))) {
+			hpfs_error(i->i_sb, "move_to_top: dnode %08x has no last de", dno);
+			hpfs_brelse4(&qbh);
+			return 0;
+		}
+		if (!de->down) break;
+		dno = de_down_pointer(de);
+		hpfs_brelse4(&qbh);
+	}
+	while (!(de = dnode_pre_last_de(dnode))) {
+		dnode_secno up = le32_to_cpu(dnode->up);
+		hpfs_brelse4(&qbh);
+		hpfs_free_dnode(i->i_sb, dno);
+		i->i_size -= 2048;
+		i->i_blocks -= 4;
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)dno << 4) | 1, 5);
+		if (up == to) return to;
+		if (!(dnode = hpfs_map_dnode(i->i_sb, up, &qbh))) return 0;
+		if (dnode->root_dnode) {
+			hpfs_error(i->i_sb, "move_to_top: got to root_dnode while moving from %08x to %08x", from, to);
+			hpfs_brelse4(&qbh);
+			return 0;
+		}
+		de = dnode_last_de(dnode);
+		if (!de || !de->down) {
+			hpfs_error(i->i_sb, "move_to_top: dnode %08x doesn't point down to %08x", up, dno);
+			hpfs_brelse4(&qbh);
+			return 0;
+		}
+		le32_add_cpu(&dnode->first_free, -4);
+		le16_add_cpu(&de->length, -4);
+		de->down = 0;
+		hpfs_mark_4buffers_dirty(&qbh);
+		dno = up;
+	}
+	t = get_pos(dnode, de);
+	for_all_poss(i, hpfs_pos_subst, t, 4);
+	for_all_poss(i, hpfs_pos_subst, t + 1, 5);
+	if (!(nde = kmalloc(le16_to_cpu(de->length), GFP_NOFS))) {
+		hpfs_error(i->i_sb, "out of memory for dirent - directory will be corrupted");
+		hpfs_brelse4(&qbh);
+		return 0;
+	}
+	memcpy(nde, de, le16_to_cpu(de->length));
+	ddno = de->down ? de_down_pointer(de) : 0;
+	hpfs_delete_de(i->i_sb, dnode, de);
+	set_last_pointer(i->i_sb, dnode, ddno);
+	hpfs_mark_4buffers_dirty(&qbh);
+	hpfs_brelse4(&qbh);
+	a = hpfs_add_to_dnode(i, to, nde->name, nde->namelen, nde, from);
+	kfree(nde);
+	if (a) return 0;
+	return dno;
+}
+
+/* 
+ * Check if a dnode is empty and delete it from the tree
+ * (chkdsk doesn't like empty dnodes)
+ */
+
+static void delete_empty_dnode(struct inode *i, dnode_secno dno)
+{
+	struct hpfs_inode_info *hpfs_inode = hpfs_i(i);
+	struct quad_buffer_head qbh;
+	struct dnode *dnode;
+	dnode_secno down, up, ndown;
+	int p;
+	struct hpfs_dirent *de;
+	int c1, c2 = 0;
+	try_it_again:
+	if (hpfs_stop_cycles(i->i_sb, dno, &c1, &c2, "delete_empty_dnode")) return;
+	if (!(dnode = hpfs_map_dnode(i->i_sb, dno, &qbh))) return;
+	if (le32_to_cpu(dnode->first_free) > 56) goto end;
+	if (le32_to_cpu(dnode->first_free) == 52 || le32_to_cpu(dnode->first_free) == 56) {
+		struct hpfs_dirent *de_end;
+		int root = dnode->root_dnode;
+		up = le32_to_cpu(dnode->up);
+		de = dnode_first_de(dnode);
+		down = de->down ? de_down_pointer(de) : 0;
+		if (hpfs_sb(i->i_sb)->sb_chk) if (root && !down) {
+			hpfs_error(i->i_sb, "delete_empty_dnode: root dnode %08x is empty", dno);
+			goto end;
+		}
+		hpfs_brelse4(&qbh);
+		hpfs_free_dnode(i->i_sb, dno);
+		i->i_size -= 2048;
+		i->i_blocks -= 4;
+		if (root) {
+			struct fnode *fnode;
+			struct buffer_head *bh;
+			struct dnode *d1;
+			struct quad_buffer_head qbh1;
+			if (hpfs_sb(i->i_sb)->sb_chk)
+				if (up != i->i_ino) {
+					hpfs_error(i->i_sb,
+						   "bad pointer to fnode, dnode %08x, pointing to %08x, should be %08llx",
+						   dno, up,
+						   i->i_ino);
+					return;
+				}
+			if ((d1 = hpfs_map_dnode(i->i_sb, down, &qbh1))) {
+				d1->up = cpu_to_le32(up);
+				d1->root_dnode = 1;
+				hpfs_mark_4buffers_dirty(&qbh1);
+				hpfs_brelse4(&qbh1);
+			}
+			if ((fnode = hpfs_map_fnode(i->i_sb, up, &bh))) {
+				fnode->u.external[0].disk_secno = cpu_to_le32(down);
+				mark_buffer_dirty(bh);
+				brelse(bh);
+			}
+			hpfs_inode->i_dno = down;
+			for_all_poss(i, hpfs_pos_subst, ((loff_t)dno << 4) | 1, (loff_t) 12);
+			return;
+		}
+		if (!(dnode = hpfs_map_dnode(i->i_sb, up, &qbh))) return;
+		p = 1;
+		de_end = dnode_end_de(dnode);
+		for (de = dnode_first_de(dnode); de < de_end; de = de_next_de(de), p++)
+			if (de->down) if (de_down_pointer(de) == dno) goto fnd;
+		hpfs_error(i->i_sb, "delete_empty_dnode: pointer to dnode %08x not found in dnode %08x", dno, up);
+		goto end;
+		fnd:
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)dno << 4) | 1, ((loff_t)up << 4) | p);
+		if (!down) {
+			de->down = 0;
+			le16_add_cpu(&de->length, -4);
+			le32_add_cpu(&dnode->first_free, -4);
+			memmove(de_next_de(de), (char *)de_next_de(de) + 4,
+				(char *)dnode + le32_to_cpu(dnode->first_free) - (char *)de_next_de(de));
+		} else {
+			struct dnode *d1;
+			struct quad_buffer_head qbh1;
+			*(dnode_secno *) ((void *) de + le16_to_cpu(de->length) - 4) = down;
+			if ((d1 = hpfs_map_dnode(i->i_sb, down, &qbh1))) {
+				d1->up = cpu_to_le32(up);
+				hpfs_mark_4buffers_dirty(&qbh1);
+				hpfs_brelse4(&qbh1);
+			}
+		}
+	} else {
+		hpfs_error(i->i_sb, "delete_empty_dnode: dnode %08x, first_free == %03x", dno, le32_to_cpu(dnode->first_free));
+		goto end;
+	}
+
+	if (!de->last) {
+		struct hpfs_dirent *de_next = de_next_de(de);
+		struct hpfs_dirent *de_cp;
+		struct dnode *d1;
+		struct quad_buffer_head qbh1;
+		if (!de_next->down) goto endm;
+		ndown = de_down_pointer(de_next);
+		if (!(de_cp = kmalloc(le16_to_cpu(de->length), GFP_NOFS))) {
+			pr_err("out of memory for dtree balancing\n");
+			goto endm;
+		}
+		memcpy(de_cp, de, le16_to_cpu(de->length));
+		hpfs_delete_de(i->i_sb, dnode, de);
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)up << 4) | p, 4);
+		for_all_poss(i, hpfs_pos_del, ((loff_t)up << 4) | p, 1);
+		if (de_cp->down) if ((d1 = hpfs_map_dnode(i->i_sb, de_down_pointer(de_cp), &qbh1))) {
+			d1->up = cpu_to_le32(ndown);
+			hpfs_mark_4buffers_dirty(&qbh1);
+			hpfs_brelse4(&qbh1);
+		}
+		hpfs_add_to_dnode(i, ndown, de_cp->name, de_cp->namelen, de_cp, de_cp->down ? de_down_pointer(de_cp) : 0);
+		/*pr_info("UP-TO-DNODE: %08x (ndown = %08x, down = %08x, dno = %08x)\n",
+		  up, ndown, down, dno);*/
+		dno = up;
+		kfree(de_cp);
+		goto try_it_again;
+	} else {
+		struct hpfs_dirent *de_prev = dnode_pre_last_de(dnode);
+		struct hpfs_dirent *de_cp;
+		struct dnode *d1;
+		struct quad_buffer_head qbh1;
+		dnode_secno dlp;
+		if (!de_prev) {
+			hpfs_error(i->i_sb, "delete_empty_dnode: empty dnode %08x", up);
+			hpfs_mark_4buffers_dirty(&qbh);
+			hpfs_brelse4(&qbh);
+			dno = up;
+			goto try_it_again;
+		}
+		if (!de_prev->down) goto endm;
+		ndown = de_down_pointer(de_prev);
+		if ((d1 = hpfs_map_dnode(i->i_sb, ndown, &qbh1))) {
+			struct hpfs_dirent *del = dnode_last_de(d1);
+			dlp = del->down ? de_down_pointer(del) : 0;
+			if (!dlp && down) {
+				if (le32_to_cpu(d1->first_free) > 2044) {
+					if (hpfs_sb(i->i_sb)->sb_chk >= 2) {
+						pr_err("unbalanced dnode tree, see hpfs.txt 4 more info\n");
+						pr_err("terminating balancing operation\n");
+					}
+					hpfs_brelse4(&qbh1);
+					goto endm;
+				}
+				if (hpfs_sb(i->i_sb)->sb_chk >= 2) {
+					pr_err("unbalanced dnode tree, see hpfs.txt 4 more info\n");
+					pr_err("goin'on\n");
+				}
+				le16_add_cpu(&del->length, 4);
+				del->down = 1;
+				le32_add_cpu(&d1->first_free, 4);
+			}
+			if (dlp && !down) {
+				le16_add_cpu(&del->length, -4);
+				del->down = 0;
+				le32_add_cpu(&d1->first_free, -4);
+			} else if (down)
+				*(__le32 *) ((void *) del + le16_to_cpu(del->length) - 4) = cpu_to_le32(down);
+		} else goto endm;
+		if (!(de_cp = kmalloc(le16_to_cpu(de_prev->length), GFP_NOFS))) {
+			pr_err("out of memory for dtree balancing\n");
+			hpfs_brelse4(&qbh1);
+			goto endm;
+		}
+		hpfs_mark_4buffers_dirty(&qbh1);
+		hpfs_brelse4(&qbh1);
+		memcpy(de_cp, de_prev, le16_to_cpu(de_prev->length));
+		hpfs_delete_de(i->i_sb, dnode, de_prev);
+		if (!de_prev->down) {
+			le16_add_cpu(&de_prev->length, 4);
+			de_prev->down = 1;
+			le32_add_cpu(&dnode->first_free, 4);
+		}
+		*(__le32 *) ((void *) de_prev + le16_to_cpu(de_prev->length) - 4) = cpu_to_le32(ndown);
+		hpfs_mark_4buffers_dirty(&qbh);
+		hpfs_brelse4(&qbh);
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)up << 4) | (p - 1), 4);
+		for_all_poss(i, hpfs_pos_subst, ((loff_t)up << 4) | p, ((loff_t)up << 4) | (p - 1));
+		if (down) if ((d1 = hpfs_map_dnode(i->i_sb, de_down_pointer(de), &qbh1))) {
+			d1->up = cpu_to_le32(ndown);
+			hpfs_mark_4buffers_dirty(&qbh1);
+			hpfs_brelse4(&qbh1);
+		}
+		hpfs_add_to_dnode(i, ndown, de_cp->name, de_cp->namelen, de_cp, dlp);
+		dno = up;
+		kfree(de_cp);
+		goto try_it_again;
+	}
+	endm:
+	hpfs_mark_4buffers_dirty(&qbh);
+	end:
+	hpfs_brelse4(&qbh);
+}
+
+
+/* Delete dirent from directory */
+
+int hpfs_remove_dirent(struct inode *i, dnode_secno dno, struct hpfs_dirent *de,
+		       struct quad_buffer_head *qbh, int depth)
+{
+	struct dnode *dnode = qbh->data;
+	dnode_secno down = 0;
+	loff_t t;
+	if (de->first || de->last) {
+		hpfs_error(i->i_sb, "hpfs_remove_dirent: attempt to delete first or last dirent in dnode %08x", dno);
+		hpfs_brelse4(qbh);
+		return 1;
+	}
+	if (de->down) down = de_down_pointer(de);
+	if (depth && (de->down || (de == dnode_first_de(dnode) && de_next_de(de)->last))) {
+		if (hpfs_check_free_dnodes(i->i_sb, FREE_DNODES_DEL)) {
+			hpfs_brelse4(qbh);
+			return 2;
+		}
+	}
+	for_all_poss(i, hpfs_pos_del, (t = get_pos(dnode, de)) + 1, 1);
+	hpfs_delete_de(i->i_sb, dnode, de);
+	hpfs_mark_4buffers_dirty(qbh);
+	hpfs_brelse4(qbh);
+	if (down) {
+		dnode_secno a = move_to_top(i, down, dno);
+		for_all_poss(i, hpfs_pos_subst, 5, t);
+		if (a) delete_empty_dnode(i, a);
+		return !a;
+	}
+	delete_empty_dnode(i, dno);
+	return 0;
+}
+
+void hpfs_count_dnodes(struct super_block *s, dnode_secno dno, int *n_dnodes,
+		       int *n_subdirs, int *n_items)
+{
+	struct dnode *dnode;
+	struct quad_buffer_head qbh;
+	struct hpfs_dirent *de;
+	dnode_secno ptr, odno = 0;
+	int c1, c2 = 0;
+	int d1, d2 = 0;
+	go_down:
+	if (n_dnodes) (*n_dnodes)++;
+	if (hpfs_sb(s)->sb_chk)
+		if (hpfs_stop_cycles(s, dno, &c1, &c2, "hpfs_count_dnodes #1")) return;
+	ptr = 0;
+	go_up:
+	if (!(dnode = hpfs_map_dnode(s, dno, &qbh))) return;
+	if (hpfs_sb(s)->sb_chk) if (odno && odno != -1 && le32_to_cpu(dnode->up) != odno)
+		hpfs_error(s, "hpfs_count_dnodes: bad up pointer; dnode %08x, down %08x points to %08x", odno, dno, le32_to_cpu(dnode->up));
+	de = dnode_first_de(dnode);
+	if (ptr) while(1) {
+		if (de->down) if (de_down_pointer(de) == ptr) goto process_de;
+		if (de->last) {
+			hpfs_brelse4(&qbh);
+			hpfs_error(s, "hpfs_count_dnodes: pointer to dnode %08x not found in dnode %08x, got here from %08x",
+				ptr, dno, odno);
+			return;
+		}
+		de = de_next_de(de);
+	}
+	next_de:
+	if (de->down) {
+		odno = dno;
+		dno = de_down_pointer(de);
+		hpfs_brelse4(&qbh);
+		goto go_down;
+	}
+	process_de:
+	if (!de->first && !de->last && de->directory && n_subdirs) (*n_subdirs)++;
+	if (!de->first && !de->last && n_items) (*n_items)++;
+	if ((de = de_next_de(de)) < dnode_end_de(dnode)) goto next_de;
+	ptr = dno;
+	dno = le32_to_cpu(dnode->up);
+	if (dnode->root_dnode) {
+		hpfs_brelse4(&qbh);
+		return;
+	}
+	hpfs_brelse4(&qbh);
+	if (hpfs_sb(s)->sb_chk)
+		if (hpfs_stop_cycles(s, ptr, &d1, &d2, "hpfs_count_dnodes #2")) return;
+	odno = -1;
+	goto go_up;
+}
+
+static struct hpfs_dirent *map_nth_dirent(struct super_block *s, dnode_secno dno, int n,
+					  struct quad_buffer_head *qbh, struct dnode **dn)
+{
+	int i;
+	struct hpfs_dirent *de, *de_end;
+	struct dnode *dnode;
+	dnode = hpfs_map_dnode(s, dno, qbh);
+	if (!dnode) return NULL;
+	if (dn) *dn=dnode;
+	de = dnode_first_de(dnode);
+	de_end = dnode_end_de(dnode);
+	for (i = 1; de < de_end; i++, de = de_next_de(de)) {
+		if (i == n) {
+			return de;
+		}	
+		if (de->last) break;
+	}
+	hpfs_brelse4(qbh);
+	hpfs_error(s, "map_nth_dirent: n too high; dnode = %08x, requested %08x", dno, n);
+	return NULL;
+}
+
+dnode_secno hpfs_de_as_down_as_possible(struct super_block *s, dnode_secno dno)
+{
+	struct quad_buffer_head qbh;
+	dnode_secno d = dno;
+	dnode_secno up = 0;
+	struct hpfs_dirent *de;
+	int c1, c2 = 0;
+
+	again:
+	if (hpfs_sb(s)->sb_chk)
+		if (hpfs_stop_cycles(s, d, &c1, &c2, "hpfs_de_as_down_as_possible"))
+			return d;
+	if (!(de = map_nth_dirent(s, d, 1, &qbh, NULL))) return dno;
+	if (hpfs_sb(s)->sb_chk)
+		if (up && le32_to_cpu(((struct dnode *)qbh.data)->up) != up)
+			hpfs_error(s, "hpfs_de_as_down_as_possible: bad up pointer; dnode %08x, down %08x points to %08x", up, d, le32_to_cpu(((struct dnode *)qbh.data)->up));
+	if (!de->down) {
+		hpfs_brelse4(&qbh);
+		return d;
+	}
+	up = d;
+	d = de_down_pointer(de);
+	hpfs_brelse4(&qbh);
+	goto again;
+}
+
+struct hpfs_dirent *map_pos_dirent(struct inode *inode, loff_t *posp,
+				   struct quad_buffer_head *qbh)
+{
+	loff_t pos;
+	unsigned c;
+	dnode_secno dno;
+	struct hpfs_dirent *de, *d;
+	struct hpfs_dirent *up_de;
+	struct hpfs_dirent *end_up_de;
+	struct dnode *dnode;
+	struct dnode *up_dnode;
+	struct quad_buffer_head qbh0;
+
+	pos = *posp;
+	dno = pos >> 6 << 2;
+	pos &= 077;
+	if (!(de = map_nth_dirent(inode->i_sb, dno, pos, qbh, &dnode)))
+		goto bail;
+
+	/* Going to the next dirent */
+	if ((d = de_next_de(de)) < dnode_end_de(dnode)) {
+		if (!(++*posp & 077)) {
+			hpfs_error(inode->i_sb,
+				"map_pos_dirent: pos crossed dnode boundary; pos = %08llx",
+				(unsigned long long)*posp);
+			goto bail;
+		}
+		/* We're going down the tree */
+		if (d->down) {
+			*posp = ((loff_t) hpfs_de_as_down_as_possible(inode->i_sb, de_down_pointer(d)) << 4) + 1;
+		}
+	
+		return de;
+	}
+
+	/* Going up */
+	if (dnode->root_dnode) goto bail;
+
+	if (!(up_dnode = hpfs_map_dnode(inode->i_sb, le32_to_cpu(dnode->up), &qbh0)))
+		goto bail;
+
+	end_up_de = dnode_end_de(up_dnode);
+	c = 0;
+	for (up_de = dnode_first_de(up_dnode); up_de < end_up_de;
+	     up_de = de_next_de(up_de)) {
+		if (!(++c & 077)) hpfs_error(inode->i_sb,
+			"map_pos_dirent: pos crossed dnode boundary; dnode = %08x", le32_to_cpu(dnode->up));
+		if (up_de->down && de_down_pointer(up_de) == dno) {
+			*posp = ((loff_t) le32_to_cpu(dnode->up) << 4) + c;
+			hpfs_brelse4(&qbh0);
+			return de;
+		}
+	}
+	
+	hpfs_error(inode->i_sb, "map_pos_dirent: pointer to dnode %08x not found in parent dnode %08x",
+		dno, le32_to_cpu(dnode->up));
+	hpfs_brelse4(&qbh0);
+	
+	bail:
+	*posp = 12;
+	return de;
+}
+
+/* Find a dirent in tree */
+
+struct hpfs_dirent *map_dirent(struct inode *inode, dnode_secno dno,
+			       const unsigned char *name, unsigned len,
+			       dnode_secno *dd, struct quad_buffer_head *qbh)
+{
+	struct dnode *dnode;
+	struct hpfs_dirent *de;
+	struct hpfs_dirent *de_end;
+	int c1, c2 = 0;
+
+	if (!S_ISDIR(inode->i_mode)) hpfs_error(inode->i_sb, "map_dirent: not a directory\n");
+	again:
+	if (hpfs_sb(inode->i_sb)->sb_chk)
+		if (hpfs_stop_cycles(inode->i_sb, dno, &c1, &c2, "map_dirent")) return NULL;
+	if (!(dnode = hpfs_map_dnode(inode->i_sb, dno, qbh))) return NULL;
+	
+	de_end = dnode_end_de(dnode);
+	for (de = dnode_first_de(dnode); de < de_end; de = de_next_de(de)) {
+		int t = hpfs_compare_names(inode->i_sb, name, len, de->name, de->namelen, de->last);
+		if (!t) {
+			if (dd) *dd = dno;
+			return de;
+		}
+		if (t < 0) {
+			if (de->down) {
+				dno = de_down_pointer(de);
+				hpfs_brelse4(qbh);
+				goto again;
+			}
+		break;
+		}
+	}
+	hpfs_brelse4(qbh);
+	return NULL;
+}
+
+/*
+ * Remove empty directory. In normal cases it is only one dnode with two
+ * entries, but we must handle also such obscure cases when it's a tree
+ * of empty dnodes.
+ */
+
+void hpfs_remove_dtree(struct super_block *s, dnode_secno dno)
+{
+	struct quad_buffer_head qbh;
+	struct dnode *dnode;
+	struct hpfs_dirent *de;
+	dnode_secno d1, d2, rdno = dno;
+	while (1) {
+		if (!(dnode = hpfs_map_dnode(s, dno, &qbh))) return;
+		de = dnode_first_de(dnode);
+		if (de->last) {
+			if (de->down) d1 = de_down_pointer(de);
+			else goto error;
+			hpfs_brelse4(&qbh);
+			hpfs_free_dnode(s, dno);
+			dno = d1;
+		} else break;
+	}
+	if (!de->first) goto error;
+	d1 = de->down ? de_down_pointer(de) : 0;
+	de = de_next_de(de);
+	if (!de->last) goto error;
+	d2 = de->down ? de_down_pointer(de) : 0;
+	hpfs_brelse4(&qbh);
+	hpfs_free_dnode(s, dno);
+	do {
+		while (d1) {
+			if (!(dnode = hpfs_map_dnode(s, dno = d1, &qbh))) return;
+			de = dnode_first_de(dnode);
+			if (!de->last) goto error;
+			d1 = de->down ? de_down_pointer(de) : 0;
+			hpfs_brelse4(&qbh);
+			hpfs_free_dnode(s, dno);
+		}
+		d1 = d2;
+		d2 = 0;
+	} while (d1);
+	return;
+	error:
+	hpfs_brelse4(&qbh);
+	hpfs_free_dnode(s, dno);
+	hpfs_error(s, "directory %08x is corrupted or not empty", rdno);
+}
+
+/* 
+ * Find dirent for specified fnode. Use truncated 15-char name in fnode as
+ * a help for searching.
+ */
+
+struct hpfs_dirent *map_fnode_dirent(struct super_block *s, fnode_secno fno,
+				     struct fnode *f, struct quad_buffer_head *qbh)
+{
+	unsigned char *name1;
+	unsigned char *name2;
+	int name1len, name2len;
+	struct dnode *d;
+	dnode_secno dno, downd;
+	struct fnode *upf;
+	struct buffer_head *bh;
+	struct hpfs_dirent *de, *de_end;
+	int c;
+	int c1, c2 = 0;
+	int d1, d2 = 0;
+	name1 = f->name;
+	if (!(name2 = kmalloc(256, GFP_NOFS))) {
+		pr_err("out of memory, can't map dirent\n");
+		return NULL;
+	}
+	if (f->len <= 15)
+		memcpy(name2, name1, name1len = name2len = f->len);
+	else {
+		memcpy(name2, name1, 15);
+		memset(name2 + 15, 0xff, 256 - 15);
+		/*name2[15] = 0xff;*/
+		name1len = 15; name2len = 256;
+	}
+	if (!(upf = hpfs_map_fnode(s, le32_to_cpu(f->up), &bh))) {
+		kfree(name2);
+		return NULL;
+	}	
+	if (!fnode_is_dir(upf)) {
+		brelse(bh);
+		hpfs_error(s, "fnode %08x has non-directory parent %08x", fno, le32_to_cpu(f->up));
+		kfree(name2);
+		return NULL;
+	}
+	dno = le32_to_cpu(upf->u.external[0].disk_secno);
+	brelse(bh);
+	go_down:
+	downd = 0;
+	go_up:
+	if (!(d = hpfs_map_dnode(s, dno, qbh))) {
+		kfree(name2);
+		return NULL;
+	}
+	de_end = dnode_end_de(d);
+	de = dnode_first_de(d);
+	if (downd) {
+		while (de < de_end) {
+			if (de->down) if (de_down_pointer(de) == downd) goto f;
+			de = de_next_de(de);
+		}
+		hpfs_error(s, "pointer to dnode %08x not found in dnode %08x", downd, dno);
+		hpfs_brelse4(qbh);
+		kfree(name2);
+		return NULL;
+	}
+	next_de:
+	if (le32_to_cpu(de->fnode) == fno) {
+		kfree(name2);
+		return de;
+	}
+	c = hpfs_compare_names(s, name1, name1len, de->name, de->namelen, de->last);
+	if (c < 0 && de->down) {
+		dno = de_down_pointer(de);
+		hpfs_brelse4(qbh);
+		if (hpfs_sb(s)->sb_chk)
+			if (hpfs_stop_cycles(s, dno, &c1, &c2, "map_fnode_dirent #1")) {
+				kfree(name2);
+				return NULL;
+		}
+		goto go_down;
+	}
+	f:
+	if (le32_to_cpu(de->fnode) == fno) {
+		kfree(name2);
+		return de;
+	}
+	c = hpfs_compare_names(s, name2, name2len, de->name, de->namelen, de->last);
+	if (c < 0 && !de->last) goto not_found;
+	if ((de = de_next_de(de)) < de_end) goto next_de;
+	if (d->root_dnode) goto not_found;
+	downd = dno;
+	dno = le32_to_cpu(d->up);
+	hpfs_brelse4(qbh);
+	if (hpfs_sb(s)->sb_chk)
+		if (hpfs_stop_cycles(s, downd, &d1, &d2, "map_fnode_dirent #2")) {
+			kfree(name2);
+			return NULL;
+		}
+	goto go_up;
+	not_found:
+	hpfs_brelse4(qbh);
+	hpfs_error(s, "dirent for fnode %08x not found", fno);
+	kfree(name2);
+	return NULL;
+}