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, 1047 insertions, 0 deletions

diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
new file mode 100644
index 000000000..eb5dcd17d
--- /dev/null
+++ b/fs/ocfs2/extent_map.c
@@ -0,0 +1,1047 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * extent_map.c
+ *
+ * Block/Cluster mapping functions
+ *
+ * Copyright (C) 2004 Oracle.  All rights reserved.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/fiemap.h>
+
+#include <cluster/masklog.h>
+
+#include "ocfs2.h"
+
+#include "alloc.h"
+#include "dlmglue.h"
+#include "extent_map.h"
+#include "inode.h"
+#include "super.h"
+#include "symlink.h"
+#include "aops.h"
+#include "ocfs2_trace.h"
+
+#include "buffer_head_io.h"
+
+/*
+ * The extent caching implementation is intentionally trivial.
+ *
+ * We only cache a small number of extents stored directly on the
+ * inode, so linear order operations are acceptable. If we ever want
+ * to increase the size of the extent map, then these algorithms must
+ * get smarter.
+ */
+
+void ocfs2_extent_map_init(struct inode *inode)
+{
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+	oi->ip_extent_map.em_num_items = 0;
+	INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
+}
+
+static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
+				      unsigned int cpos,
+				      struct ocfs2_extent_map_item **ret_emi)
+{
+	unsigned int range;
+	struct ocfs2_extent_map_item *emi;
+
+	*ret_emi = NULL;
+
+	list_for_each_entry(emi, &em->em_list, ei_list) {
+		range = emi->ei_cpos + emi->ei_clusters;
+
+		if (cpos >= emi->ei_cpos && cpos < range) {
+			list_move(&emi->ei_list, &em->em_list);
+
+			*ret_emi = emi;
+			break;
+		}
+	}
+}
+
+static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
+				   unsigned int *phys, unsigned int *len,
+				   unsigned int *flags)
+{
+	unsigned int coff;
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	struct ocfs2_extent_map_item *emi;
+
+	spin_lock(&oi->ip_lock);
+
+	__ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
+	if (emi) {
+		coff = cpos - emi->ei_cpos;
+		*phys = emi->ei_phys + coff;
+		if (len)
+			*len = emi->ei_clusters - coff;
+		if (flags)
+			*flags = emi->ei_flags;
+	}
+
+	spin_unlock(&oi->ip_lock);
+
+	if (emi == NULL)
+		return -ENOENT;
+
+	return 0;
+}
+
+/*
+ * Forget about all clusters equal to or greater than cpos.
+ */
+void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
+{
+	struct ocfs2_extent_map_item *emi, *n;
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	struct ocfs2_extent_map *em = &oi->ip_extent_map;
+	LIST_HEAD(tmp_list);
+	unsigned int range;
+
+	spin_lock(&oi->ip_lock);
+	list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
+		if (emi->ei_cpos >= cpos) {
+			/* Full truncate of this record. */
+			list_move(&emi->ei_list, &tmp_list);
+			BUG_ON(em->em_num_items == 0);
+			em->em_num_items--;
+			continue;
+		}
+
+		range = emi->ei_cpos + emi->ei_clusters;
+		if (range > cpos) {
+			/* Partial truncate */
+			emi->ei_clusters = cpos - emi->ei_cpos;
+		}
+	}
+	spin_unlock(&oi->ip_lock);
+
+	list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
+		list_del(&emi->ei_list);
+		kfree(emi);
+	}
+}
+
+/*
+ * Is any part of emi2 contained within emi1
+ */
+static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
+				 struct ocfs2_extent_map_item *emi2)
+{
+	unsigned int range1, range2;
+
+	/*
+	 * Check if logical start of emi2 is inside emi1
+	 */
+	range1 = emi1->ei_cpos + emi1->ei_clusters;
+	if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
+		return 1;
+
+	/*
+	 * Check if logical end of emi2 is inside emi1
+	 */
+	range2 = emi2->ei_cpos + emi2->ei_clusters;
+	if (range2 > emi1->ei_cpos && range2 <= range1)
+		return 1;
+
+	return 0;
+}
+
+static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
+				  struct ocfs2_extent_map_item *src)
+{
+	dest->ei_cpos = src->ei_cpos;
+	dest->ei_phys = src->ei_phys;
+	dest->ei_clusters = src->ei_clusters;
+	dest->ei_flags = src->ei_flags;
+}
+
+/*
+ * Try to merge emi with ins. Returns 1 if merge succeeds, zero
+ * otherwise.
+ */
+static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
+					 struct ocfs2_extent_map_item *ins)
+{
+	/*
+	 * Handle contiguousness
+	 */
+	if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
+	    ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
+	    ins->ei_flags == emi->ei_flags) {
+		emi->ei_clusters += ins->ei_clusters;
+		return 1;
+	} else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
+		   (ins->ei_cpos + ins->ei_clusters) == emi->ei_cpos &&
+		   ins->ei_flags == emi->ei_flags) {
+		emi->ei_phys = ins->ei_phys;
+		emi->ei_cpos = ins->ei_cpos;
+		emi->ei_clusters += ins->ei_clusters;
+		return 1;
+	}
+
+	/*
+	 * Overlapping extents - this shouldn't happen unless we've
+	 * split an extent to change it's flags. That is exceedingly
+	 * rare, so there's no sense in trying to optimize it yet.
+	 */
+	if (ocfs2_ei_is_contained(emi, ins) ||
+	    ocfs2_ei_is_contained(ins, emi)) {
+		ocfs2_copy_emi_fields(emi, ins);
+		return 1;
+	}
+
+	/* No merge was possible. */
+	return 0;
+}
+
+/*
+ * In order to reduce complexity on the caller, this insert function
+ * is intentionally liberal in what it will accept.
+ *
+ * The only rule is that the truncate call *must* be used whenever
+ * records have been deleted. This avoids inserting overlapping
+ * records with different physical mappings.
+ */
+void ocfs2_extent_map_insert_rec(struct inode *inode,
+				 struct ocfs2_extent_rec *rec)
+{
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	struct ocfs2_extent_map *em = &oi->ip_extent_map;
+	struct ocfs2_extent_map_item *emi, *new_emi = NULL;
+	struct ocfs2_extent_map_item ins;
+
+	ins.ei_cpos = le32_to_cpu(rec->e_cpos);
+	ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
+					       le64_to_cpu(rec->e_blkno));
+	ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
+	ins.ei_flags = rec->e_flags;
+
+search:
+	spin_lock(&oi->ip_lock);
+
+	list_for_each_entry(emi, &em->em_list, ei_list) {
+		if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
+			list_move(&emi->ei_list, &em->em_list);
+			spin_unlock(&oi->ip_lock);
+			goto out;
+		}
+	}
+
+	/*
+	 * No item could be merged.
+	 *
+	 * Either allocate and add a new item, or overwrite the last recently
+	 * inserted.
+	 */
+
+	if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
+		if (new_emi == NULL) {
+			spin_unlock(&oi->ip_lock);
+
+			new_emi = kmalloc_obj(*new_emi, GFP_NOFS);
+			if (new_emi == NULL)
+				goto out;
+
+			goto search;
+		}
+
+		ocfs2_copy_emi_fields(new_emi, &ins);
+		list_add(&new_emi->ei_list, &em->em_list);
+		em->em_num_items++;
+		new_emi = NULL;
+	} else {
+		BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
+		emi = list_entry(em->em_list.prev,
+				 struct ocfs2_extent_map_item, ei_list);
+		list_move(&emi->ei_list, &em->em_list);
+		ocfs2_copy_emi_fields(emi, &ins);
+	}
+
+	spin_unlock(&oi->ip_lock);
+
+out:
+	kfree(new_emi);
+}
+
+static int ocfs2_last_eb_is_empty(struct inode *inode,
+				  struct ocfs2_dinode *di)
+{
+	int ret, next_free;
+	u64 last_eb_blk = le64_to_cpu(di->i_last_eb_blk);
+	struct buffer_head *eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+
+	ret = ocfs2_read_extent_block(INODE_CACHE(inode), last_eb_blk, &eb_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+	el = &eb->h_list;
+
+	if (el->l_tree_depth) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has non zero tree depth in leaf block %llu\n",
+			    inode->i_ino,
+			    (unsigned long long)eb_bh->b_blocknr);
+		ret = -EROFS;
+		goto out;
+	}
+
+	next_free = le16_to_cpu(el->l_next_free_rec);
+
+	if (next_free == 0 ||
+	    (next_free == 1 && ocfs2_is_empty_extent(&el->l_recs[0])))
+		ret = 1;
+
+out:
+	brelse(eb_bh);
+	return ret;
+}
+
+/*
+ * Return the 1st index within el which contains an extent start
+ * larger than v_cluster.
+ */
+static int ocfs2_search_for_hole_index(struct ocfs2_extent_list *el,
+				       u32 v_cluster)
+{
+	int i;
+	struct ocfs2_extent_rec *rec;
+
+	for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
+		rec = &el->l_recs[i];
+
+		if (v_cluster < le32_to_cpu(rec->e_cpos))
+			break;
+	}
+
+	return i;
+}
+
+/*
+ * Figure out the size of a hole which starts at v_cluster within the given
+ * extent list.
+ *
+ * If there is no more allocation past v_cluster, we return the maximum
+ * cluster size minus v_cluster.
+ *
+ * If we have in-inode extents, then el points to the dinode list and
+ * eb_bh is NULL. Otherwise, eb_bh should point to the extent block
+ * containing el.
+ */
+int ocfs2_figure_hole_clusters(struct ocfs2_caching_info *ci,
+			       struct ocfs2_extent_list *el,
+			       struct buffer_head *eb_bh,
+			       u32 v_cluster,
+			       u32 *num_clusters)
+{
+	int ret, i;
+	struct buffer_head *next_eb_bh = NULL;
+	struct ocfs2_extent_block *eb, *next_eb;
+
+	i = ocfs2_search_for_hole_index(el, v_cluster);
+
+	if (i == le16_to_cpu(el->l_next_free_rec) && eb_bh) {
+		eb = (struct ocfs2_extent_block *)eb_bh->b_data;
+
+		/*
+		 * Check the next leaf for any extents.
+		 */
+
+		if (le64_to_cpu(eb->h_next_leaf_blk) == 0ULL)
+			goto no_more_extents;
+
+		ret = ocfs2_read_extent_block(ci,
+					      le64_to_cpu(eb->h_next_leaf_blk),
+					      &next_eb_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		next_eb = (struct ocfs2_extent_block *)next_eb_bh->b_data;
+		el = &next_eb->h_list;
+		i = ocfs2_search_for_hole_index(el, v_cluster);
+	}
+
+no_more_extents:
+	if (i == le16_to_cpu(el->l_next_free_rec)) {
+		/*
+		 * We're at the end of our existing allocation. Just
+		 * return the maximum number of clusters we could
+		 * possibly allocate.
+		 */
+		*num_clusters = UINT_MAX - v_cluster;
+	} else {
+		*num_clusters = le32_to_cpu(el->l_recs[i].e_cpos) - v_cluster;
+	}
+
+	ret = 0;
+out:
+	brelse(next_eb_bh);
+	return ret;
+}
+
+static int ocfs2_get_clusters_nocache(struct inode *inode,
+				      struct buffer_head *di_bh,
+				      u32 v_cluster, unsigned int *hole_len,
+				      struct ocfs2_extent_rec *ret_rec,
+				      unsigned int *is_last)
+{
+	int i, ret, tree_height, len;
+	struct ocfs2_dinode *di;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_list *el;
+	struct ocfs2_extent_rec *rec;
+	struct buffer_head *eb_bh = NULL;
+
+	memset(ret_rec, 0, sizeof(*ret_rec));
+	if (is_last)
+		*is_last = 0;
+
+	di = (struct ocfs2_dinode *) di_bh->b_data;
+	el = &di->id2.i_list;
+	tree_height = le16_to_cpu(el->l_tree_depth);
+
+	if (tree_height > 0) {
+		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+				      &eb_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+		el = &eb->h_list;
+
+		if (el->l_tree_depth) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu has non zero tree depth in leaf block %llu\n",
+				    inode->i_ino,
+				    (unsigned long long)eb_bh->b_blocknr);
+			ret = -EROFS;
+			goto out;
+		}
+	}
+
+	if (le16_to_cpu(el->l_next_free_rec) > le16_to_cpu(el->l_count)) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has an invalid extent (next_free_rec %u, count %u)\n",
+			    inode->i_ino,
+			    le16_to_cpu(el->l_next_free_rec),
+			    le16_to_cpu(el->l_count));
+		ret = -EROFS;
+		goto out;
+	}
+
+	i = ocfs2_search_extent_list(el, v_cluster);
+	if (i == -1) {
+		/*
+		 * Holes can be larger than the maximum size of an
+		 * extent, so we return their lengths in a separate
+		 * field.
+		 */
+		if (hole_len) {
+			ret = ocfs2_figure_hole_clusters(INODE_CACHE(inode),
+							 el, eb_bh,
+							 v_cluster, &len);
+			if (ret) {
+				mlog_errno(ret);
+				goto out;
+			}
+
+			*hole_len = len;
+		}
+		goto out_hole;
+	}
+
+	rec = &el->l_recs[i];
+
+	BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
+
+	if (!rec->e_blkno) {
+		ocfs2_error(inode->i_sb,
+			    "Inode %llu has bad extent record (%u, %u, 0)\n",
+			    inode->i_ino,
+			    le32_to_cpu(rec->e_cpos),
+			    ocfs2_rec_clusters(el, rec));
+		ret = -EROFS;
+		goto out;
+	}
+
+	*ret_rec = *rec;
+
+	/*
+	 * Checking for last extent is potentially expensive - we
+	 * might have to look at the next leaf over to see if it's
+	 * empty.
+	 *
+	 * The first two checks are to see whether the caller even
+	 * cares for this information, and if the extent is at least
+	 * the last in it's list.
+	 *
+	 * If those hold true, then the extent is last if any of the
+	 * additional conditions hold true:
+	 *  - Extent list is in-inode
+	 *  - Extent list is right-most
+	 *  - Extent list is 2nd to rightmost, with empty right-most
+	 */
+	if (is_last) {
+		if (i == (le16_to_cpu(el->l_next_free_rec) - 1)) {
+			if (tree_height == 0)
+				*is_last = 1;
+			else if (eb->h_blkno == di->i_last_eb_blk)
+				*is_last = 1;
+			else if (eb->h_next_leaf_blk == di->i_last_eb_blk) {
+				ret = ocfs2_last_eb_is_empty(inode, di);
+				if (ret < 0) {
+					mlog_errno(ret);
+					goto out;
+				}
+				if (ret == 1)
+					*is_last = 1;
+			}
+		}
+	}
+
+out_hole:
+	ret = 0;
+out:
+	brelse(eb_bh);
+	return ret;
+}
+
+static void ocfs2_relative_extent_offsets(struct super_block *sb,
+					  u32 v_cluster,
+					  struct ocfs2_extent_rec *rec,
+					  u32 *p_cluster, u32 *num_clusters)
+
+{
+	u32 coff = v_cluster - le32_to_cpu(rec->e_cpos);
+
+	*p_cluster = ocfs2_blocks_to_clusters(sb, le64_to_cpu(rec->e_blkno));
+	*p_cluster = *p_cluster + coff;
+
+	if (num_clusters)
+		*num_clusters = le16_to_cpu(rec->e_leaf_clusters) - coff;
+}
+
+int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
+			     u32 *p_cluster, u32 *num_clusters,
+			     struct ocfs2_extent_list *el,
+			     unsigned int *extent_flags)
+{
+	int ret = 0, i;
+	struct buffer_head *eb_bh = NULL;
+	struct ocfs2_extent_block *eb;
+	struct ocfs2_extent_rec *rec;
+	u32 coff;
+
+	if (el->l_tree_depth) {
+		ret = ocfs2_find_leaf(INODE_CACHE(inode), el, v_cluster,
+				      &eb_bh);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		eb = (struct ocfs2_extent_block *) eb_bh->b_data;
+		el = &eb->h_list;
+
+		if (el->l_tree_depth) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu has non zero tree depth in xattr leaf block %llu\n",
+				    inode->i_ino,
+				    (unsigned long long)eb_bh->b_blocknr);
+			ret = -EROFS;
+			goto out;
+		}
+	}
+
+	i = ocfs2_search_extent_list(el, v_cluster);
+	if (i == -1) {
+		ret = -EROFS;
+		mlog_errno(ret);
+		goto out;
+	} else {
+		rec = &el->l_recs[i];
+		BUG_ON(v_cluster < le32_to_cpu(rec->e_cpos));
+
+		if (!rec->e_blkno) {
+			ocfs2_error(inode->i_sb,
+				    "Inode %llu has bad extent record (%u, %u, 0) in xattr\n",
+				    inode->i_ino,
+				    le32_to_cpu(rec->e_cpos),
+				    ocfs2_rec_clusters(el, rec));
+			ret = -EROFS;
+			goto out;
+		}
+		coff = v_cluster - le32_to_cpu(rec->e_cpos);
+		*p_cluster = ocfs2_blocks_to_clusters(inode->i_sb,
+						    le64_to_cpu(rec->e_blkno));
+		*p_cluster = *p_cluster + coff;
+		if (num_clusters)
+			*num_clusters = ocfs2_rec_clusters(el, rec) - coff;
+
+		if (extent_flags)
+			*extent_flags = rec->e_flags;
+	}
+out:
+	brelse(eb_bh);
+	return ret;
+}
+
+int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
+		       u32 *p_cluster, u32 *num_clusters,
+		       unsigned int *extent_flags)
+{
+	int ret;
+	unsigned int hole_len, flags = 0;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_extent_rec rec;
+
+	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+		ret = -ERANGE;
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
+				      num_clusters, extent_flags);
+	if (ret == 0)
+		goto out;
+
+	ret = ocfs2_read_inode_block(inode, &di_bh);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	ret = ocfs2_get_clusters_nocache(inode, di_bh, v_cluster, &hole_len,
+					 &rec, NULL);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	if (rec.e_blkno == 0ULL) {
+		/*
+		 * A hole was found. Return some canned values that
+		 * callers can key on. If asked for, num_clusters will
+		 * be populated with the size of the hole.
+		 */
+		*p_cluster = 0;
+		if (num_clusters) {
+			*num_clusters = hole_len;
+		}
+	} else {
+		ocfs2_relative_extent_offsets(inode->i_sb, v_cluster, &rec,
+					      p_cluster, num_clusters);
+		flags = rec.e_flags;
+
+		ocfs2_extent_map_insert_rec(inode, &rec);
+	}
+
+	if (extent_flags)
+		*extent_flags = flags;
+
+out:
+	brelse(di_bh);
+	return ret;
+}
+
+/*
+ * This expects alloc_sem to be held. The allocation cannot change at
+ * all while the map is in the process of being updated.
+ */
+int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
+				u64 *ret_count, unsigned int *extent_flags)
+{
+	int ret;
+	int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
+	u32 cpos, num_clusters, p_cluster;
+	u64 boff = 0;
+
+	cpos = ocfs2_blocks_to_clusters(inode->i_sb, v_blkno);
+
+	ret = ocfs2_get_clusters(inode, cpos, &p_cluster, &num_clusters,
+				 extent_flags);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	/*
+	 * p_cluster == 0 indicates a hole.
+	 */
+	if (p_cluster) {
+		boff = ocfs2_clusters_to_blocks(inode->i_sb, p_cluster);
+		boff += (v_blkno & (u64)(bpc - 1));
+	}
+
+	*p_blkno = boff;
+
+	if (ret_count) {
+		*ret_count = ocfs2_clusters_to_blocks(inode->i_sb, num_clusters);
+		*ret_count -= v_blkno & (u64)(bpc - 1);
+	}
+
+out:
+	return ret;
+}
+
+/*
+ * The ocfs2_fiemap_inline() may be a little bit misleading, since
+ * it not only handles the fiemap for inlined files, but also deals
+ * with the fast symlink, cause they have no difference for extent
+ * mapping per se.
+ *
+ * Must be called with ip_alloc_sem semaphore held.
+ */
+static int ocfs2_fiemap_inline(struct inode *inode, struct buffer_head *di_bh,
+			       struct fiemap_extent_info *fieinfo,
+			       u64 map_start)
+{
+	int ret;
+	unsigned int id_count;
+	struct ocfs2_dinode *di;
+	u64 phys;
+	u32 flags = FIEMAP_EXTENT_DATA_INLINE|FIEMAP_EXTENT_LAST;
+	struct ocfs2_inode_info *oi = OCFS2_I(inode);
+	lockdep_assert_held_read(&oi->ip_alloc_sem);
+
+	di = (struct ocfs2_dinode *)di_bh->b_data;
+	if (ocfs2_inode_is_fast_symlink(inode))
+		id_count = ocfs2_fast_symlink_chars(inode->i_sb);
+	else
+		id_count = le16_to_cpu(di->id2.i_data.id_count);
+
+	if (map_start < id_count) {
+		phys = oi->ip_blkno << inode->i_sb->s_blocksize_bits;
+		if (ocfs2_inode_is_fast_symlink(inode))
+			phys += offsetof(struct ocfs2_dinode, id2.i_symlink);
+		else
+			phys += offsetof(struct ocfs2_dinode,
+					 id2.i_data.id_data);
+
+		/* Release the ip_alloc_sem to prevent deadlock on page fault */
+		up_read(&OCFS2_I(inode)->ip_alloc_sem);
+		ret = fiemap_fill_next_extent(fieinfo, 0, phys, id_count,
+					      flags);
+		down_read(&OCFS2_I(inode)->ip_alloc_sem);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+		 u64 map_start, u64 map_len)
+{
+	int ret, is_last;
+	u32 mapping_end, cpos;
+	unsigned int hole_size;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	u64 len_bytes, phys_bytes, virt_bytes;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_extent_rec rec;
+
+	ret = fiemap_prep(inode, fieinfo, map_start, &map_len, 0);
+	if (ret)
+		return ret;
+
+	ret = ocfs2_inode_lock(inode, &di_bh, 0);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	down_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+	/*
+	 * Handle inline-data and fast symlink separately.
+	 */
+	if ((OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) ||
+	    ocfs2_inode_is_fast_symlink(inode)) {
+		ret = ocfs2_fiemap_inline(inode, di_bh, fieinfo, map_start);
+		goto out_unlock;
+	}
+
+	cpos = map_start >> osb->s_clustersize_bits;
+	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
+					       map_start + map_len);
+	is_last = 0;
+	while (cpos < mapping_end && !is_last) {
+		u32 fe_flags;
+
+		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
+						 &hole_size, &rec, &is_last);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_unlock;
+		}
+
+		if (rec.e_blkno == 0ULL) {
+			cpos += hole_size;
+			continue;
+		}
+
+		fe_flags = 0;
+		if (rec.e_flags & OCFS2_EXT_UNWRITTEN)
+			fe_flags |= FIEMAP_EXTENT_UNWRITTEN;
+		if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
+			fe_flags |= FIEMAP_EXTENT_SHARED;
+		if (is_last)
+			fe_flags |= FIEMAP_EXTENT_LAST;
+		len_bytes = (u64)le16_to_cpu(rec.e_leaf_clusters) << osb->s_clustersize_bits;
+		phys_bytes = le64_to_cpu(rec.e_blkno) << osb->sb->s_blocksize_bits;
+		virt_bytes = (u64)le32_to_cpu(rec.e_cpos) << osb->s_clustersize_bits;
+		/* Release the ip_alloc_sem to prevent deadlock on page fault */
+		up_read(&OCFS2_I(inode)->ip_alloc_sem);
+		ret = fiemap_fill_next_extent(fieinfo, virt_bytes, phys_bytes,
+					      len_bytes, fe_flags);
+		down_read(&OCFS2_I(inode)->ip_alloc_sem);
+		if (ret)
+			break;
+
+		cpos = le32_to_cpu(rec.e_cpos)+ le16_to_cpu(rec.e_leaf_clusters);
+	}
+
+	if (ret > 0)
+		ret = 0;
+
+out_unlock:
+	brelse(di_bh);
+
+	up_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+	ocfs2_inode_unlock(inode, 0);
+out:
+
+	return ret;
+}
+
+/* Is IO overwriting allocated blocks? */
+int ocfs2_overwrite_io(struct inode *inode, struct buffer_head *di_bh,
+		       u64 map_start, u64 map_len)
+{
+	int ret = 0, is_last;
+	u32 mapping_end, cpos;
+	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+	struct ocfs2_extent_rec rec;
+
+	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+		if (ocfs2_size_fits_inline_data(di_bh, map_start + map_len))
+			return ret;
+		else
+			return -EAGAIN;
+	}
+
+	cpos = map_start >> osb->s_clustersize_bits;
+	mapping_end = ocfs2_clusters_for_bytes(inode->i_sb,
+					       map_start + map_len);
+	is_last = 0;
+	while (cpos < mapping_end && !is_last) {
+		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos,
+						 NULL, &rec, &is_last);
+		if (ret) {
+			mlog_errno(ret);
+			goto out;
+		}
+
+		if (rec.e_blkno == 0ULL)
+			break;
+
+		if (rec.e_flags & OCFS2_EXT_REFCOUNTED)
+			break;
+
+		cpos = le32_to_cpu(rec.e_cpos) +
+			le16_to_cpu(rec.e_leaf_clusters);
+	}
+
+	if (cpos < mapping_end)
+		ret = -EAGAIN;
+out:
+	return ret;
+}
+
+int ocfs2_seek_data_hole_offset(struct file *file, loff_t *offset, int whence)
+{
+	struct inode *inode = file->f_mapping->host;
+	int ret;
+	unsigned int is_last = 0, is_data = 0;
+	u16 cs_bits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+	u32 cpos, cend, clen, hole_size;
+	u64 extoff, extlen;
+	struct buffer_head *di_bh = NULL;
+	struct ocfs2_extent_rec rec;
+
+	BUG_ON(whence != SEEK_DATA && whence != SEEK_HOLE);
+
+	ret = ocfs2_inode_lock(inode, &di_bh, 0);
+	if (ret) {
+		mlog_errno(ret);
+		goto out;
+	}
+
+	down_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+	if (*offset >= i_size_read(inode)) {
+		ret = -ENXIO;
+		goto out_unlock;
+	}
+
+	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+		if (whence == SEEK_HOLE)
+			*offset = i_size_read(inode);
+		goto out_unlock;
+	}
+
+	clen = 0;
+	cpos = *offset >> cs_bits;
+	cend = ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
+
+	while (cpos < cend && !is_last) {
+		ret = ocfs2_get_clusters_nocache(inode, di_bh, cpos, &hole_size,
+						 &rec, &is_last);
+		if (ret) {
+			mlog_errno(ret);
+			goto out_unlock;
+		}
+
+		extoff = cpos;
+		extoff <<= cs_bits;
+
+		if (rec.e_blkno == 0ULL) {
+			clen = hole_size;
+			is_data = 0;
+		} else {
+			clen = le16_to_cpu(rec.e_leaf_clusters) -
+				(cpos - le32_to_cpu(rec.e_cpos));
+			is_data = (rec.e_flags & OCFS2_EXT_UNWRITTEN) ?  0 : 1;
+		}
+
+		if ((!is_data && whence == SEEK_HOLE) ||
+		    (is_data && whence == SEEK_DATA)) {
+			if (extoff > *offset)
+				*offset = extoff;
+			goto out_unlock;
+		}
+
+		if (!is_last)
+			cpos += clen;
+	}
+
+	if (whence == SEEK_HOLE) {
+		extoff = cpos;
+		extoff <<= cs_bits;
+		extlen = clen;
+		extlen <<=  cs_bits;
+
+		if ((extoff + extlen) > i_size_read(inode))
+			extlen = i_size_read(inode) - extoff;
+		extoff += extlen;
+		if (extoff > *offset)
+			*offset = extoff;
+		goto out_unlock;
+	}
+
+	ret = -ENXIO;
+
+out_unlock:
+
+	brelse(di_bh);
+
+	up_read(&OCFS2_I(inode)->ip_alloc_sem);
+
+	ocfs2_inode_unlock(inode, 0);
+out:
+	return ret;
+}
+
+int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr,
+			   struct buffer_head *bhs[], int flags,
+			   int (*validate)(struct super_block *sb,
+					   struct buffer_head *bh))
+{
+	int rc = 0;
+	u64 p_block, p_count;
+	int i, count, done = 0;
+
+	trace_ocfs2_read_virt_blocks(
+	     inode, (unsigned long long)v_block, nr, bhs, flags,
+	     validate);
+
+	if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >=
+	    i_size_read(inode)) {
+		BUG_ON(!(flags & OCFS2_BH_READAHEAD));
+		goto out;
+	}
+
+	while (done < nr) {
+		if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) {
+			rc = -EAGAIN;
+			mlog(ML_ERROR,
+				 "Inode #%llu ip_alloc_sem is temporarily unavailable\n",
+				 (unsigned long long)OCFS2_I(inode)->ip_blkno);
+			break;
+		}
+		rc = ocfs2_extent_map_get_blocks(inode, v_block + done,
+						 &p_block, &p_count, NULL);
+		up_read(&OCFS2_I(inode)->ip_alloc_sem);
+		if (rc) {
+			mlog_errno(rc);
+			break;
+		}
+
+		if (!p_block) {
+			rc = -EIO;
+			mlog(ML_ERROR,
+			     "Inode #%llu contains a hole at offset %llu\n",
+			     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+			     (unsigned long long)(v_block + done) <<
+			     inode->i_sb->s_blocksize_bits);
+			break;
+		}
+
+		count = nr - done;
+		if (p_count < count)
+			count = p_count;
+
+		/*
+		 * If the caller passed us bhs, they should have come
+		 * from a previous readahead call to this function.  Thus,
+		 * they should have the right b_blocknr.
+		 */
+		for (i = 0; i < count; i++) {
+			if (!bhs[done + i])
+				continue;
+			BUG_ON(bhs[done + i]->b_blocknr != (p_block + i));
+		}
+
+		rc = ocfs2_read_blocks(INODE_CACHE(inode), p_block, count,
+				       bhs + done, flags, validate);
+		if (rc) {
+			mlog_errno(rc);
+			break;
+		}
+		done += count;
+	}
+
+out:
+	return rc;
+}
+
+