ext4: iterate over buffer heads correctly in move_extent_per_page()

[ Upstream commit 87f9a031af48defee9f34c6aaf06d6f1988c244d ]

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>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 165f309bafcc2ac46012100f18f65cf56786d622..f498c34b4688644e035d68b863c6c524b7cdeb1b 100644 (file)
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -397,6 +397,7 @@ 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);