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, 710 insertions, 0 deletions

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
new file mode 100644
index 000000000..8d7b81e69
--- /dev/null
+++ b/fs/ext4/dir.c
@@ -0,0 +1,710 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/ext4/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include <linux/filelock.h>
+#include <linux/slab.h>
+#include <linux/iversion.h>
+#include <linux/unicode.h>
+#include "ext4.h"
+#include "xattr.h"
+
+static int ext4_dx_readdir(struct file *, struct dir_context *);
+
+/**
+ * is_dx_dir() - check if a directory is using htree indexing
+ * @inode: directory inode
+ *
+ * Check if the given dir-inode refers to an htree-indexed directory
+ * (or a directory which could potentially get converted to use htree
+ * indexing).
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (ext4_has_feature_dir_index(inode->i_sb) &&
+	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
+	     ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
+	     ext4_has_inline_data(inode)))
+		return 1;
+
+	return 0;
+}
+
+static bool is_fake_dir_entry(struct ext4_dir_entry_2 *de)
+{
+	/* Check if . or .. , or skip if namelen is 0 */
+	if ((de->name_len > 0) && (de->name_len <= 2) && (de->name[0] == '.') &&
+	    (de->name[1] == '.' || de->name[1] == '\0'))
+		return true;
+	/* Check if this is a csum entry */
+	if (de->file_type == EXT4_FT_DIR_CSUM)
+		return true;
+	return false;
+}
+
+/*
+ * Return 0 if the directory entry is OK, and 1 if there is a problem
+ *
+ * Note: this is the opposite of what ext2 and ext3 historically returned...
+ *
+ * bh passed here can be an inode block or a dir data block, depending
+ * on the inode inline data flag.
+ */
+int __ext4_check_dir_entry(const char *function, unsigned int line,
+			   struct inode *dir, struct file *filp,
+			   struct ext4_dir_entry_2 *de,
+			   struct buffer_head *bh, char *buf, int size,
+			   unsigned int offset)
+{
+	const char *error_msg = NULL;
+	const int rlen = ext4_rec_len_from_disk(de->rec_len,
+						dir->i_sb->s_blocksize);
+	const int next_offset = ((char *) de - buf) + rlen;
+	bool fake = is_fake_dir_entry(de);
+	bool has_csum = ext4_has_feature_metadata_csum(dir->i_sb);
+
+	if (unlikely(rlen < ext4_dir_rec_len(1, fake ? NULL : dir)))
+		error_msg = "rec_len is smaller than minimal";
+	else if (unlikely(rlen % 4 != 0))
+		error_msg = "rec_len % 4 != 0";
+	else if (unlikely(rlen < ext4_dir_rec_len(de->name_len,
+							fake ? NULL : dir)))
+		error_msg = "rec_len is too small for name_len";
+	else if (unlikely(next_offset > size))
+		error_msg = "directory entry overrun";
+	else if (unlikely(next_offset > size - ext4_dir_rec_len(1,
+						  has_csum ? NULL : dir) &&
+			  next_offset != size))
+		error_msg = "directory entry too close to block end";
+	else if (unlikely(le32_to_cpu(de->inode) >
+			le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
+		error_msg = "inode out of bounds";
+	else if (unlikely(next_offset == size && de->name_len == 1 &&
+			  de->name[0] == '.'))
+		error_msg = "'.' directory cannot be the last in data block";
+	else
+		return 0;
+
+	if (filp)
+		ext4_error_file(filp, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u, "
+				"inode=%u, rec_len=%d, size=%d fake=%d",
+				error_msg, offset, le32_to_cpu(de->inode),
+				rlen, size, fake);
+	else
+		ext4_error_inode(dir, function, line, bh->b_blocknr,
+				"bad entry in directory: %s - offset=%u, "
+				"inode=%u, rec_len=%d, size=%d fake=%d",
+				 error_msg, offset, le32_to_cpu(de->inode),
+				 rlen, size, fake);
+
+	return 1;
+}
+
+static int ext4_readdir(struct file *file, struct dir_context *ctx)
+{
+	unsigned int offset;
+	int i;
+	struct ext4_dir_entry_2 *de;
+	int err;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *bh = NULL;
+	struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
+	struct dir_private_info *info = file->private_data;
+	bool has_csum = ext4_has_feature_metadata_csum(sb);
+
+	err = fscrypt_prepare_readdir(inode);
+	if (err)
+		return err;
+
+	if (is_dx_dir(inode)) {
+		err = ext4_dx_readdir(file, ctx);
+		if (err != ERR_BAD_DX_DIR)
+			return err;
+
+		/* Can we just clear INDEX flag to ignore htree information? */
+		if (!has_csum) {
+			/*
+			 * We don't set the inode dirty flag since it's not
+			 * critical that it gets flushed back to the disk.
+			 */
+			ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
+		}
+	}
+
+	if (ext4_has_inline_data(inode)) {
+		int has_inline_data = 1;
+		err = ext4_read_inline_dir(file, ctx,
+					   &has_inline_data);
+		if (has_inline_data)
+			return err;
+	}
+
+	if (IS_ENCRYPTED(inode)) {
+		err = fscrypt_fname_alloc_buffer(EXT4_NAME_LEN, &fstr);
+		if (err < 0)
+			return err;
+	}
+
+	while (ctx->pos < inode->i_size) {
+		struct ext4_map_blocks map;
+
+		if (fatal_signal_pending(current)) {
+			err = -ERESTARTSYS;
+			goto errout;
+		}
+		cond_resched();
+		offset = ctx->pos & (sb->s_blocksize - 1);
+		map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
+		map.m_len = 1;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err == 0) {
+			/* m_len should never be zero but let's avoid
+			 * an infinite loop if it somehow is */
+			if (map.m_len == 0)
+				map.m_len = 1;
+			ctx->pos += map.m_len * sb->s_blocksize;
+			continue;
+		}
+		if (err > 0) {
+			pgoff_t index = map.m_pblk << inode->i_blkbits >>
+					PAGE_SHIFT;
+			if (!ra_has_index(&file->f_ra, index))
+				page_cache_sync_readahead(
+					sb->s_bdev->bd_mapping,
+					&file->f_ra, file, index,
+					1 << EXT4_SB(sb)->s_min_folio_order);
+			file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
+			bh = ext4_bread(NULL, inode, map.m_lblk, 0);
+			if (IS_ERR(bh)) {
+				err = PTR_ERR(bh);
+				bh = NULL;
+				goto errout;
+			}
+		}
+
+		if (!bh) {
+			/* corrupt size?  Maybe no more blocks to read */
+			if (ctx->pos > inode->i_blocks << 9)
+				break;
+			ctx->pos += sb->s_blocksize - offset;
+			continue;
+		}
+
+		/* Check the checksum */
+		if (!buffer_verified(bh) &&
+		    !ext4_dirblock_csum_verify(inode, bh)) {
+			EXT4_ERROR_FILE(file, 0, "directory fails checksum "
+					"at offset %llu",
+					(unsigned long long)ctx->pos);
+			ctx->pos += sb->s_blocksize - offset;
+			brelse(bh);
+			bh = NULL;
+			continue;
+		}
+		set_buffer_verified(bh);
+
+		/* If the dir block has changed since the last call to
+		 * readdir(2), then we might be pointing to an invalid
+		 * dirent right now.  Scan from the start of the block
+		 * to make sure. */
+		if (!inode_eq_iversion(inode, info->cookie)) {
+			for (i = 0;
+			     i <= sb->s_blocksize -
+				  ext4_dir_rec_len(1, has_csum ? NULL : inode) &&
+			     i < offset;) {
+				de = (struct ext4_dir_entry_2 *)
+					(bh->b_data + i);
+				/* It's too expensive to do a full
+				 * dirent test each time round this
+				 * loop, but we do have to test at
+				 * least that it is non-zero.  A
+				 * failure will be detected in the
+				 * dirent test below. */
+				if (ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize) < ext4_dir_rec_len(1,
+									inode))
+					break;
+				i += ext4_rec_len_from_disk(de->rec_len,
+							    sb->s_blocksize);
+			}
+			offset = i;
+			ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
+				| offset;
+			info->cookie = inode_query_iversion(inode);
+		}
+
+		if (unlikely(offset < sb->s_blocksize &&
+			     offset > sb->s_blocksize -
+			     ext4_dir_rec_len(1, has_csum ? NULL : inode))) {
+			EXT4_ERROR_FILE(file, bh->b_blocknr,
+					"bad entry in directory: %s - offset=%u, size=%lu",
+					"directory entry too close to block end",
+					offset, sb->s_blocksize);
+			ctx->pos = round_up(ctx->pos, sb->s_blocksize);
+			goto next_block;
+		}
+
+		while (ctx->pos < inode->i_size
+		       && offset < sb->s_blocksize) {
+			de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
+			if (ext4_check_dir_entry(inode, file, de, bh,
+						 bh->b_data, bh->b_size,
+						 offset)) {
+				/*
+				 * On error, skip to the next block
+				 */
+				ctx->pos = (ctx->pos |
+						(sb->s_blocksize - 1)) + 1;
+				break;
+			}
+			offset += ext4_rec_len_from_disk(de->rec_len,
+					sb->s_blocksize);
+			if (le32_to_cpu(de->inode)) {
+				if (!IS_ENCRYPTED(inode)) {
+					if (!dir_emit(ctx, de->name,
+					    de->name_len,
+					    le32_to_cpu(de->inode),
+					    get_dtype(sb, de->file_type)))
+						goto done;
+				} else {
+					int save_len = fstr.len;
+					struct fscrypt_str de_name =
+							FSTR_INIT(de->name,
+								de->name_len);
+					u32 hash;
+					u32 minor_hash;
+
+					if (IS_CASEFOLDED(inode)) {
+						hash = EXT4_DIRENT_HASH(de);
+						minor_hash = EXT4_DIRENT_MINOR_HASH(de);
+					} else {
+						hash = 0;
+						minor_hash = 0;
+					}
+
+					/* Directory is encrypted */
+					err = fscrypt_fname_disk_to_usr(inode,
+						hash, minor_hash, &de_name, &fstr);
+					de_name = fstr;
+					fstr.len = save_len;
+					if (err)
+						goto errout;
+					if (!dir_emit(ctx,
+					    de_name.name, de_name.len,
+					    le32_to_cpu(de->inode),
+					    get_dtype(sb, de->file_type)))
+						goto done;
+				}
+			}
+			ctx->pos += ext4_rec_len_from_disk(de->rec_len,
+						sb->s_blocksize);
+		}
+next_block:
+		if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
+			goto done;
+		brelse(bh);
+		bh = NULL;
+	}
+done:
+	err = 0;
+errout:
+	fscrypt_fname_free_buffer(&fstr);
+	brelse(bh);
+	return err;
+}
+
+static inline int is_32bit_api(void)
+{
+#ifdef CONFIG_COMPAT
+	return in_compat_syscall();
+#else
+	return (BITS_PER_LONG == 32);
+#endif
+}
+
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value for dx directories
+ *
+ * Upper layer (for example NFS) should specify FMODE_32BITHASH or
+ * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
+ * directly on both 32-bit and 64-bit nodes, under such case, neither
+ * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
+ */
+static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return major >> 1;
+	else
+		return ((__u64)(major >> 1) << 32) | (__u64)minor;
+}
+
+static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return (pos << 1) & 0xffffffff;
+	else
+		return ((pos >> 32) << 1) & 0xffffffff;
+}
+
+static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return 0;
+	else
+		return pos & 0xffffffff;
+}
+
+/*
+ * Return 32- or 64-bit end-of-file for dx directories
+ */
+static inline loff_t ext4_get_htree_eof(struct file *filp)
+{
+	if ((filp->f_mode & FMODE_32BITHASH) ||
+	    (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
+		return EXT4_HTREE_EOF_32BIT;
+	else
+		return EXT4_HTREE_EOF_64BIT;
+}
+
+
+/*
+ * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
+ * directories, where the "offset" is in terms of the filename hash
+ * value instead of the byte offset.
+ *
+ * Because we may return a 64-bit hash that is well beyond offset limits,
+ * we need to pass the max hash as the maximum allowable offset in
+ * the htree directory case.
+ *
+ * For non-htree, ext4_llseek already chooses the proper max offset.
+ */
+static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	struct dir_private_info *info = file->private_data;
+	int dx_dir = is_dx_dir(inode);
+	loff_t ret, htree_max = ext4_get_htree_eof(file);
+
+	if (likely(dx_dir))
+		ret = generic_file_llseek_size(file, offset, whence,
+						    htree_max, htree_max);
+	else
+		ret = ext4_llseek(file, offset, whence);
+	info->cookie = inode_peek_iversion(inode) - 1;
+	return ret;
+}
+
+/*
+ * This structure holds the nodes of the red-black tree used to store
+ * the directory entry in hash order.
+ */
+struct fname {
+	__u32		hash;
+	__u32		minor_hash;
+	struct rb_node	rb_hash;
+	struct fname	*next;
+	__u32		inode;
+	__u8		name_len;
+	__u8		file_type;
+	char		name[] __counted_by(name_len);
+};
+
+/*
+ * This function implements a non-recursive way of freeing all of the
+ * nodes in the red-black tree.
+ */
+static void free_rb_tree_fname(struct rb_root *root)
+{
+	struct fname *fname, *next;
+
+	rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
+		while (fname) {
+			struct fname *old = fname;
+			fname = fname->next;
+			kfree(old);
+		}
+
+	*root = RB_ROOT;
+}
+
+static void ext4_htree_init_dir_info(struct file *filp, loff_t pos)
+{
+	struct dir_private_info *p = filp->private_data;
+
+	if (is_dx_dir(file_inode(filp)) && !p->initialized) {
+		p->curr_hash = pos2maj_hash(filp, pos);
+		p->curr_minor_hash = pos2min_hash(filp, pos);
+		p->initialized = true;
+	}
+}
+
+void ext4_htree_free_dir_info(struct dir_private_info *p)
+{
+	free_rb_tree_fname(&p->root);
+	kfree(p);
+}
+
+/*
+ * Given a directory entry, enter it into the fname rb tree.
+ *
+ * When filename encryption is enabled, the dirent will hold the
+ * encrypted filename, while the htree will hold decrypted filename.
+ * The decrypted filename is passed in via ent_name.  parameter.
+ */
+int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
+			     __u32 minor_hash,
+			    struct ext4_dir_entry_2 *dirent,
+			    struct fscrypt_str *ent_name)
+{
+	struct rb_node **p, *parent = NULL;
+	struct fname *fname, *new_fn;
+	struct dir_private_info *info;
+
+	info = dir_file->private_data;
+	p = &info->root.rb_node;
+
+	/* Create and allocate the fname structure */
+	new_fn = kzalloc_flex(*new_fn, name, ent_name->len + 1);
+	if (!new_fn)
+		return -ENOMEM;
+	new_fn->hash = hash;
+	new_fn->minor_hash = minor_hash;
+	new_fn->inode = le32_to_cpu(dirent->inode);
+	new_fn->name_len = ent_name->len;
+	new_fn->file_type = dirent->file_type;
+	memcpy(new_fn->name, ent_name->name, ent_name->len);
+
+	while (*p) {
+		parent = *p;
+		fname = rb_entry(parent, struct fname, rb_hash);
+
+		/*
+		 * If the hash and minor hash match up, then we put
+		 * them on a linked list.  This rarely happens...
+		 */
+		if ((new_fn->hash == fname->hash) &&
+		    (new_fn->minor_hash == fname->minor_hash)) {
+			new_fn->next = fname->next;
+			fname->next = new_fn;
+			return 0;
+		}
+
+		if (new_fn->hash < fname->hash)
+			p = &(*p)->rb_left;
+		else if (new_fn->hash > fname->hash)
+			p = &(*p)->rb_right;
+		else if (new_fn->minor_hash < fname->minor_hash)
+			p = &(*p)->rb_left;
+		else /* if (new_fn->minor_hash > fname->minor_hash) */
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&new_fn->rb_hash, parent, p);
+	rb_insert_color(&new_fn->rb_hash, &info->root);
+	return 0;
+}
+
+
+
+/*
+ * This is a helper function for ext4_dx_readdir.  It calls filldir
+ * for all entries on the fname linked list.  (Normally there is only
+ * one entry on the linked list, unless there are 62 bit hash collisions.)
+ */
+static int call_filldir(struct file *file, struct dir_context *ctx,
+			struct fname *fname)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct super_block *sb = inode->i_sb;
+
+	if (!fname) {
+		ext4_msg(sb, KERN_ERR, "%s:%d: inode #%llu: comm %s: "
+			 "called with null fname?!?", __func__, __LINE__,
+			 inode->i_ino, current->comm);
+		return 0;
+	}
+	ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
+	while (fname) {
+		if (!dir_emit(ctx, fname->name,
+				fname->name_len,
+				fname->inode,
+				get_dtype(sb, fname->file_type))) {
+			info->extra_fname = fname;
+			return 1;
+		}
+		fname = fname->next;
+	}
+	return 0;
+}
+
+static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct dir_private_info *info = file->private_data;
+	struct inode *inode = file_inode(file);
+	struct fname *fname;
+	int ret = 0;
+
+	ext4_htree_init_dir_info(file, ctx->pos);
+
+	if (ctx->pos == ext4_get_htree_eof(file))
+		return 0;	/* EOF */
+
+	/* Some one has messed with f_pos; reset the world */
+	if (info->last_pos != ctx->pos) {
+		free_rb_tree_fname(&info->root);
+		info->curr_node = NULL;
+		info->extra_fname = NULL;
+		info->curr_hash = pos2maj_hash(file, ctx->pos);
+		info->curr_minor_hash = pos2min_hash(file, ctx->pos);
+	}
+
+	/*
+	 * If there are any leftover names on the hash collision
+	 * chain, return them first.
+	 */
+	if (info->extra_fname) {
+		if (call_filldir(file, ctx, info->extra_fname))
+			goto finished;
+		info->extra_fname = NULL;
+		goto next_node;
+	} else if (!info->curr_node)
+		info->curr_node = rb_first(&info->root);
+
+	while (1) {
+		/*
+		 * Fill the rbtree if we have no more entries,
+		 * or the inode has changed since we last read in the
+		 * cached entries.
+		 */
+		if ((!info->curr_node) ||
+		    !inode_eq_iversion(inode, info->cookie)) {
+			info->curr_node = NULL;
+			free_rb_tree_fname(&info->root);
+			info->cookie = inode_query_iversion(inode);
+			ret = ext4_htree_fill_tree(file, info->curr_hash,
+						   info->curr_minor_hash,
+						   &info->next_hash);
+			if (ret < 0)
+				goto finished;
+			if (ret == 0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_node = rb_first(&info->root);
+		}
+
+		fname = rb_entry(info->curr_node, struct fname, rb_hash);
+		info->curr_hash = fname->hash;
+		info->curr_minor_hash = fname->minor_hash;
+		if (call_filldir(file, ctx, fname))
+			break;
+	next_node:
+		info->curr_node = rb_next(info->curr_node);
+		if (info->curr_node) {
+			fname = rb_entry(info->curr_node, struct fname,
+					 rb_hash);
+			info->curr_hash = fname->hash;
+			info->curr_minor_hash = fname->minor_hash;
+		} else {
+			if (info->next_hash == ~0) {
+				ctx->pos = ext4_get_htree_eof(file);
+				break;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	}
+finished:
+	info->last_pos = ctx->pos;
+	return ret < 0 ? ret : 0;
+}
+
+static int ext4_release_dir(struct inode *inode, struct file *filp)
+{
+	if (filp->private_data)
+		ext4_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
+		      int buf_size)
+{
+	struct ext4_dir_entry_2 *de;
+	int rlen;
+	unsigned int offset = 0;
+	char *top;
+
+	de = buf;
+	top = buf + buf_size;
+	while ((char *) de < top) {
+		if (ext4_check_dir_entry(dir, NULL, de, bh,
+					 buf, buf_size, offset))
+			return -EFSCORRUPTED;
+		rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
+		de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
+		offset += rlen;
+	}
+	if ((char *) de > top)
+		return -EFSCORRUPTED;
+
+	return 0;
+}
+
+static int ext4_dir_open(struct inode *inode, struct file *file)
+{
+	struct dir_private_info *info;
+
+	info = kzalloc_obj(*info);
+	if (!info)
+		return -ENOMEM;
+	file->private_data = info;
+	return 0;
+}
+
+const struct file_operations ext4_dir_operations = {
+	.open		= ext4_dir_open,
+	.llseek		= ext4_dir_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= ext4_readdir,
+	.unlocked_ioctl = ext4_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext4_compat_ioctl,
+#endif
+	.fsync		= ext4_sync_file,
+	.release	= ext4_release_dir,
+	.setlease	= generic_setlease,
+};