Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

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;
+}