ext4: Fix insertion point of extent in mext_insert_across_blocks()

If the leaf node has 2 extent space or fewer and EXT4_IOC_MOVE_EXT
ioctl is called with the file offset where after the 2nd extent
covers, mext_insert_across_blocks() always tries to insert extent into
the first extent.  As a result, the file gets corrupted because of
wrong extent order.  The patch fixes this problem.

Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 1654eb862d74d030eb4758342cc96730f64bb1d4..9eca1c0ec5460e04cb7de52854d0d5c38454d1a2 100644 (file)
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -252,6 +252,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
                }
 
                o_start->ee_len = start_ext->ee_len;
+               eblock = le32_to_cpu(start_ext->ee_block);
                new_flag = 1;
 
        } else if (start_ext->ee_len && new_ext->ee_len &&
@@ -262,6 +263,7 @@ mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
                 * orig  |------------------------------|
                 */
                o_start->ee_len = start_ext->ee_len;
+               eblock = le32_to_cpu(start_ext->ee_block);
                new_flag = 1;
 
        } else if (!start_ext->ee_len && new_ext->ee_len &&
@@ -502,6 +504,7 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
                le32_to_cpu(oext->ee_block) + oext_alen) {
                start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
                                               le32_to_cpu(oext->ee_block));
+               start_ext.ee_block = oext->ee_block;
                copy_extent_status(oext, &start_ext);
        } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
                prev_ext = oext - 1;
@@ -515,6 +518,7 @@ mext_leaf_block(handle_t *handle, struct inode *orig_inode,
                        start_ext.ee_len = cpu_to_le16(
                                ext4_ext_get_actual_len(prev_ext) +
                                new_ext_alen);
+                       start_ext.ee_block = oext->ee_block;
                        copy_extent_status(prev_ext, &start_ext);
                        new_ext.ee_len = 0;
                }