2 files changed, 21 insertions, 27 deletions

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c
index 4248ac1dcf5..bfebe7e3799 100644
--- a/fs/ext4/ext4_common.c
+++ b/fs/ext4/ext4_common.c
@@ -1617,12 +1617,13 @@ long int read_allocated_block(struct ext2_inode *inode, int fileblock)
 		- get_fs()->dev_desc->log2blksz;
 
 	if (le32_to_cpu(inode->flags) & EXT4_EXTENTS_FL) {
+		long int startblock, endblock;
 		char *buf = zalloc(blksz);
 		if (!buf)
 			return -ENOMEM;
 		struct ext4_extent_header *ext_block;
 		struct ext4_extent *extent;
-		int i = -1;
+		int i;
 		ext_block =
 			ext4fs_get_extent_block(ext4fs_root, buf,
 						(struct ext4_extent_header *)
@@ -1636,28 +1637,26 @@ long int read_allocated_block(struct ext2_inode *inode, int fileblock)
 
 		extent = (struct ext4_extent *)(ext_block + 1);
 
-		do {
-			i++;
-			if (i >= le16_to_cpu(ext_block->eh_entries))
-				break;
-		} while (fileblock >= le32_to_cpu(extent[i].ee_block));
-		if (--i >= 0) {
-			fileblock -= le32_to_cpu(extent[i].ee_block);
-			if (fileblock >= le16_to_cpu(extent[i].ee_len)) {
+		for (i = 0; i < le16_to_cpu(ext_block->eh_entries); i++) {
+			startblock = le32_to_cpu(extent[i].ee_block);
+			endblock = startblock + le16_to_cpu(extent[i].ee_len);
+
+			if (startblock > fileblock) {
+				/* Sparse file */
 				free(buf);
 				return 0;
-			}
 
-			start = le16_to_cpu(extent[i].ee_start_hi);
-			start = (start << 32) +
+			} else if (fileblock < endblock) {
+				start = le16_to_cpu(extent[i].ee_start_hi);
+				start = (start << 32) +
 					le32_to_cpu(extent[i].ee_start_lo);
-			free(buf);
-			return fileblock + start;
+				free(buf);
+				return (fileblock - startblock) + start;
+			}
 		}
 
-		printf("Extent Error\n");
 		free(buf);
-		return -1;
+		return 0;
 	}
 
 	/* Direct blocks. */
diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
index 30787377708..7187dcfb056 100644
--- a/fs/ext4/ext4fs.c
+++ b/fs/ext4/ext4fs.c
@@ -65,8 +65,8 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
 	short status;
 
 	/* Adjust len so it we can't read past the end of the file. */
-	if (len > filesize)
-		len = filesize;
+	if (len + pos > filesize)
+		len = (filesize - pos);
 
 	blockcnt = lldiv(((len + pos) + blocksize - 1), blocksize);
 
@@ -190,12 +190,12 @@ int ext4fs_size(const char *filename, loff_t *size)
 	return ext4fs_open(filename, size);
 }
 
-int ext4fs_read(char *buf, loff_t len, loff_t *actread)
+int ext4fs_read(char *buf, loff_t offset, loff_t len, loff_t *actread)
 {
 	if (ext4fs_root == NULL || ext4fs_file == NULL)
-		return 0;
+		return -1;
 
-	return ext4fs_read_file(ext4fs_file, 0, len, buf, actread);
+	return ext4fs_read_file(ext4fs_file, offset, len, buf, actread);
 }
 
 int ext4fs_probe(struct blk_desc *fs_dev_desc,
@@ -217,11 +217,6 @@ int ext4_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
 	loff_t file_len;
 	int ret;
 
-	if (offset != 0) {
-		printf("** Cannot support non-zero offset **\n");
-		return -1;
-	}
-
 	ret = ext4fs_open(filename, &file_len);
 	if (ret < 0) {
 		printf("** File not found %s **\n", filename);
@@ -231,7 +226,7 @@ int ext4_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
 	if (len == 0)
 		len = file_len;
 
-	return ext4fs_read(buf, len, len_read);
+	return ext4fs_read(buf, offset, len, len_read);
 }
 
 int ext4fs_uuid(char *uuid_str)