ext4: fix extent tree corruption caused by hole punch

commit c36575e663e302dbaa4d16b9c72d2c9a913a9aef upstream.

When depth of extent tree is greater than 1, logical start value of
interior node is not correctly updated in ext4_ext_rm_idx.

Signed-off-by: Forrest Liu <forrestl@synology.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Ashish Sangwan <ashishsangwan2@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 611647b28a4dd3c0e0b7fdc5b5693a3ccdd5270e..680df5dd0c54947dc913ffe68a901e24293d29d5 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2140,13 +2140,14 @@ ext4_ext_in_cache(struct inode *inode, ext4_lblk_t block,
  * last index in the block only.
  */
 static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
-                       struct ext4_ext_path *path)
+                       struct ext4_ext_path *path, int depth)
 {
        int err;
        ext4_fsblk_t leaf;
 
        /* free index block */
-       path--;
+       depth--;
+       path = path + depth;
        leaf = ext4_idx_pblock(path->p_idx);
        if (unlikely(path->p_hdr->eh_entries == 0)) {
                EXT4_ERROR_INODE(inode, "path->p_hdr->eh_entries == 0");
@@ -2162,6 +2163,19 @@ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
        ext_debug("index is empty, remove it, free block %llu\n", leaf);
        ext4_free_blocks(handle, inode, NULL, leaf, 1,
                         EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
+
+       while (--depth >= 0) {
+               if (path->p_idx != EXT_FIRST_INDEX(path->p_hdr))
+                       break;
+               path--;
+               err = ext4_ext_get_access(handle, inode, path);
+               if (err)
+                       break;
+               path->p_idx->ei_block = (path+1)->p_idx->ei_block;
+               err = ext4_ext_dirty(handle, inode, path);
+               if (err)
+                       break;
+       }
        return err;
 }
 
@@ -2509,7 +2523,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
        /* if this leaf is free, then we should
         * remove it from index block above */
        if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
-               err = ext4_ext_rm_idx(handle, inode, path + depth);
+               err = ext4_ext_rm_idx(handle, inode, path, depth);
 
 out:
        return err;
@@ -2639,7 +2653,7 @@ again:
                                /* index is empty, remove it;
                                 * handle must be already prepared by the
                                 * truncatei_leaf() */
-                               err = ext4_ext_rm_idx(handle, inode, path + i);
+                               err = ext4_ext_rm_idx(handle, inode, path, i);
                        }
                        /* root level has p_bh == NULL, brelse() eats this */
                        brelse(path[i].p_bh);