diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index e717dfd..05b9a3a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2222,6 +2222,10 @@ extern int ext4_move_extents(struct file *o_filp, struct file *d_filp,
 			     __u64 start_orig, __u64 start_donor,
 			     __u64 len, __u64 *moved_len);
 
+/* extent.c */
+extern int ext4_find_desired_extent(struct inode *inode, loff_t *offset,
+				    int origin);
+
 /* page-io.c */
 extern int __init ext4_init_pageio(void);
 extern void ext4_exit_pageio(void);
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 095c36f..ca7a339 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -116,6 +116,14 @@ struct ext4_ext_path {
 };
 
 /*
+ * Structure for retrieving extent offset for SEEK_DATA/SEEK_HOLE.
+ */
+struct ext4_extent_seek_info {
+	unsigned int origin;	/* SEEK_DATA or SEEK_HOLE */
+	loff_t offset;		/* input/output offset */
+};
+
+/*
  * structure for external API
  */
 
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 57cf568..a339e00 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3901,6 +3901,240 @@ int ext4_convert_unwritten_extents(struct inode *inode, loff_t offset,
 }
 
 /*
+ * Callback function called for each extent to gather SEEK_DATA/SEEK_HOLE
+ * information.
+ */
+static int ext4_ext_seek_cb(struct inode *inode, ext4_lblk_t next,
+			    struct ext4_ext_cache *newex,
+			    struct ext4_extent *ex,
+			    void *data)
+{
+	__u64	logical;
+	__u32	flags = 0;
+	int	ret = 0;
+	unsigned char blksize_bits;
+	struct ext4_extent_seek_info *ext_seek_info = data;
+
+	blksize_bits = inode->i_sb->s_blocksize_bits;
+	logical = (__u64)newex->ec_block << blksize_bits;
+
+	/*
+	 * No extent in extent-tree contains block @newex->ec_start,
+	 * then the block may stay in 1)a hole or 2)delayed-extent.
+	 *
+	 * Holes or delayed-extents are processed as follows.
+	 * 1. lookup dirty pages with specified range in pagecache.
+	 *    If no page is got, then there is no delayed-extent and
+	 *    return with EXT_CONTINUE if SEEK_DATA; return EXT_BREAK
+	 *    with extent offset if SEEK_HOLE.
+	 * 2. find the 1st mapped buffer,
+	 * 3. check if the mapped buffer is both in the request range
+	 *    and a delayed buffer. If not, there is no delayed-extent,
+	 *    then return with EXT_CONTINUE if SEEK_DATA, or return
+	 *    EXT_BREAK if SEEK_HOLE and extent offset.
+	 * 4. a delayed-extent is found, return the extent offset if
+	 *    SEEK_DATA and EXT_BREAK.
+	 */
+	if (newex->ec_start == 0) {
+		ext4_lblk_t	end = 0;
+		pgoff_t		last_offset;
+		pgoff_t		offset;
+		pgoff_t		index;
+		pgoff_t		start_index = 0;
+		struct page	**pages = NULL;
+		struct buffer_head *bh = NULL;
+		struct buffer_head *head = NULL;
+		unsigned int nr_pages = PAGE_SIZE / sizeof(struct page *);
+
+		pages = kmalloc(PAGE_SIZE, GFP_KERNEL);
+		if (pages == NULL)
+			return -ENOMEM;
+
+		offset = logical >> PAGE_SHIFT;
+repeat:
+		last_offset = offset;
+		head = NULL;
+
+		ret = find_get_pages_tag(inode->i_mapping, &offset,
+					 PAGECACHE_TAG_DIRTY, nr_pages, pages);
+
+		/* Not a delay allocated extent. */
+		if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
+			/* First time, try to find a mapped buffer. */
+			if (ret == 0) {
+out:
+				for (index = 0; index < ret; index++)
+					page_cache_release(pages[index]);
+				/* just a hole. */
+				kfree(pages);
+
+				/* If SEEK_HOLE, return the logical offset. */
+				if (ext_seek_info->origin == SEEK_HOLE) {
+					ext_seek_info->offset = logical;
+					return EXT_BREAK;
+				}
+
+				return EXT_CONTINUE;
+			}
+
+			index = 0;
+next_page:
+			/* Try to find the 1st mapped buffer. */
+			end = ((__u64)pages[index]->index << PAGE_SHIFT) >>
+				  blksize_bits;
+			if (!page_has_buffers(pages[index]))
+				goto out;
+			head = page_buffers(pages[index]);
+			if (!head)
+				goto out;
+
+			index++;
+			bh = head;
+			do {
+				/* The buffer is out of the request range. */
+				if (end >= newex->ec_block + newex->ec_len)
+					goto out;
+
+				if (buffer_mapped(bh) &&
+				    end >= newex->ec_block) {
+					start_index = index - 1;
+					/* get the 1st mapped buffer. */
+					goto found_mapped_buffer;
+				}
+
+				bh = bh->b_this_page;
+				end++;
+			} while (bh != head);
+
+			/* No mapped buffer in the range found in this page,
+			 * We need to look up next page.
+			 */
+			if (index >= ret) {
+				/* There is no page left, but we need to limit
+				 * newex->ec_len.
+				 */
+				newex->ec_len = end - newex->ec_block;
+				goto out;
+			}
+			goto next_page;
+		} else {
+			/*Find contiguous delayed buffers. */
+			if (ret > 0 && pages[0]->index == last_offset)
+				head = page_buffers(pages[0]);
+			bh = head;
+			index = 1;
+			start_index = 0;
+		}
+
+found_mapped_buffer:
+		if (bh != NULL && buffer_delay(bh)) {
+			/* 1st or contiguous delayed buffer found. */
+			if (!(flags & FIEMAP_EXTENT_DELALLOC)) {
+				/*
+				 * 1st delayed buffer found, record
+				 * the start of extent.
+				 */
+				flags |= FIEMAP_EXTENT_DELALLOC;
+				newex->ec_block = end;
+				logical = (__u64)end << blksize_bits;
+			}
+			/* Find contiguous delayed buffers. */
+			do {
+				if (!buffer_delay(bh))
+					goto found_delayed_extent;
+				bh = bh->b_this_page;
+				end++;
+			} while (bh != head);
+
+			for (; index < ret; index++) {
+				if (!page_has_buffers(pages[index])) {
+					bh = NULL;
+					break;
+				}
+				head = page_buffers(pages[index]);
+				if (!head) {
+					bh = NULL;
+					break;
+				}
+
+				if (pages[index]->index !=
+				    pages[start_index]->index + index
+				    - start_index) {
+					/* Blocks are not contiguous. */
+					bh = NULL;
+					break;
+				}
+				bh = head;
+				do {
+					if (!buffer_delay(bh))
+						/* Delayed-extent ends. */
+						goto found_delayed_extent;
+					bh = bh->b_this_page;
+					end++;
+				} while (bh != head);
+			}
+		} else if (!(flags & FIEMAP_EXTENT_DELALLOC))
+			/* a hole found. */
+			goto out;
+
+found_delayed_extent:
+		newex->ec_len = min(end - newex->ec_block,
+				    (ext4_lblk_t)EXT_INIT_MAX_LEN);
+		if (ret == nr_pages && bh != NULL &&
+			newex->ec_len < EXT_INIT_MAX_LEN &&
+			buffer_delay(bh)) {
+			/* Have not collected an extent and continue. */
+			for (index = 0; index < ret; index++)
+				page_cache_release(pages[index]);
+			goto repeat;
+		}
+
+		for (index = 0; index < ret; index++)
+			page_cache_release(pages[index]);
+		kfree(pages);
+	}
+
+	if (ret < 0)
+		return ret;
+
+	if (ext_seek_info->origin == SEEK_DATA) {
+		ext_seek_info->offset = logical;
+		return EXT_BREAK;
+	}
+
+	return EXT_CONTINUE;
+}
+
+int ext4_find_desired_extent(struct inode *inode, loff_t *offset, int origin)
+{
+	ext4_lblk_t start_blk;
+	ext4_lblk_t end_blk;
+	ext4_lblk_t len_blks;
+	struct ext4_extent_seek_info ext_seek_info;
+	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
+	int error = 0;
+
+	/* Only support seeking extents based file. */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+		return -ENOTSUPP;
+
+	start_blk = *offset >> blkbits;
+	if (start_blk >= EXT_MAX_BLOCKS)
+		return -ENXIO;
+
+	end_blk = i_size_read(inode) >> blkbits;
+	len_blks = ((ext4_lblk_t)end_blk) - start_blk + 1;
+
+	ext_seek_info.origin = origin;
+	error = ext4_ext_walk_space(inode, start_blk, len_blks,
+				    ext4_ext_seek_cb, &ext_seek_info);
+	if (!error)
+		*offset = ext_seek_info.offset;
+
+	return error;
+}
+
+/*
  * Callback function called for each extent to gather FIEMAP information.
  */
 static int ext4_ext_fiemap_cb(struct inode *inode, ext4_lblk_t next,
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index e4095e9..48579d5 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -219,6 +219,7 @@ loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
 {
 	struct inode *inode = file->f_mapping->host;
 	loff_t maxbytes;
+	int ret;
 
 	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 		maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
@@ -241,21 +242,20 @@ loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
 		 * In the generic case the entire file is data, so as long as
 		 * offset isn't at the end of the file then the offset is data.
 		 */
-		if (offset >= inode->i_size) {
-			mutex_unlock(&inode->i_mutex);
-			return -ENXIO;
-		}
-		break;
 	case SEEK_HOLE:
 		/*
 		 * There is a virtual hole at the end of the file, so as long as
 		 * offset isn't i_size or larger, return i_size.
 		 */
-		if (offset >= inode->i_size) {
+		if (offset >= i_size_read(inode)) {
 			mutex_unlock(&inode->i_mutex);
 			return -ENXIO;
 		}
-		offset = inode->i_size;
+		ret = ext4_find_desired_extent(inode, &offset, origin);
+		if (ret) {
+			mutex_unlock(&inode->i_mutex);
+			return ret;
+		}
 		break;
 	}