diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 3e295d3350a9..4d3014b5a3f9 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5343,8 +5343,7 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, if (!extent) goto out; - stop = le32_to_cpu(extent->ee_block) + - ext4_ext_get_actual_len(extent); + stop = le32_to_cpu(extent->ee_block); /* * In case of left shift, Don't start shifting extents until we make @@ -5383,8 +5382,12 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, else iterator = &stop; - /* Its safe to start updating extents */ - while (start < stop) { + /* + * Its safe to start updating extents. Start and stop are unsigned, so + * in case of right shift if extent with 0 block is reached, iterator + * becomes NULL to indicate the end of the loop. + */ + while (iterator && start <= stop) { path = ext4_find_extent(inode, *iterator, &path, 0); if (IS_ERR(path)) return PTR_ERR(path); @@ -5412,8 +5415,11 @@ ext4_ext_shift_extents(struct inode *inode, handle_t *handle, ext4_ext_get_actual_len(extent); } else { extent = EXT_FIRST_EXTENT(path[depth].p_hdr); - *iterator = le32_to_cpu(extent->ee_block) > 0 ? - le32_to_cpu(extent->ee_block) - 1 : 0; + if (le32_to_cpu(extent->ee_block) > 0) + *iterator = le32_to_cpu(extent->ee_block) - 1; + else + /* Beginning is reached, end of the loop */ + iterator = NULL; /* Update path extent in case we need to stop */ while (le32_to_cpu(extent->ee_block) < start) extent++;