From 92bd5b69d7e7096fffc8cab08cc6886fe22df77d Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 9 Aug 2014 12:33:11 -0400 Subject: [PATCH 2/5] resize2fs: disable the meta_bg feature if necessary When shrinking a file system, if the number block groups drops below the point where we started using the meta_bg layout, disable the meta_bg feature and set s_first_meta_bg to zero. This is necessary to avoid creating an invalid/corrupted file system after the shrink. Addresses-Debian-Bug: #756922 Signed-off-by: Theodore Ts'o Reported-by: Marcin Wolcendorf Tested-by: Marcin Wolcendorf --- resize/resize2fs.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/resize/resize2fs.c b/resize/resize2fs.c index a73390de..a2ff29ad 100644 --- a/resize/resize2fs.c +++ b/resize/resize2fs.c @@ -461,6 +461,13 @@ retry: fs->super->s_reserved_gdt_blocks = new; } + if ((fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) && + (fs->super->s_first_meta_bg > fs->desc_blocks)) { + fs->super->s_feature_incompat &= + ~EXT2_FEATURE_INCOMPAT_META_BG; + fs->super->s_first_meta_bg = 0; + } + /* * If we are shrinking the number of block groups, we're done * and can exit now. @@ -946,13 +953,15 @@ static errcode_t blocks_to_move(ext2_resize_t rfs) ext2fs_mark_block_bitmap2(rfs->reserve_blocks, blk); } - if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) { + if (old_fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) old_blocks = old_fs->super->s_first_meta_bg; + else + old_blocks = old_fs->desc_blocks + + old_fs->super->s_reserved_gdt_blocks; + if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) new_blocks = fs->super->s_first_meta_bg; - } else { - old_blocks = old_fs->desc_blocks + old_fs->super->s_reserved_gdt_blocks; + else new_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks; - } if (old_blocks == new_blocks) { retval = 0; -- 2.21.3