ext4: iterate over buffer heads correctly in move_extent_per_page()

BugLink: http://bugs.launchpad.net/bugs/1588945
commit 6ffe77bad545f4a7c8edd2a4ee797ccfcd894ab4 upstream.

In commit bcff24887d00 ("ext4: don't read blocks from disk after extents
being swapped") bh is not updated correctly in the for loop and wrong
data has been written to disk. generic/324 catches this on sub-page
block size ext4.

Fixes: bcff24887d00 ("ext4: don't read blocks from disk after extentsbeing swapped")
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 9bdbf98240a0ab6eb4f5004a7408332b20d0cc4d..796ff0eafd3c352beccb2347edcc3df87fc91422 100644 (file)
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -390,6 +390,7 @@ data_copy:
                *err = ext4_get_block(orig_inode, orig_blk_offset + i, bh, 0);
                if (*err < 0)
                        break;
+               bh = bh->b_this_page;
        }
        if (!*err)
                *err = block_commit_write(pagep[0], from, from + replaced_size);