From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: [PATCH 3/6] resize2fs: disable the meta_bg feature if necessary Date: Sat, 9 Aug 2014 13:10:17 -0400 Message-ID: <1407604220-2620-3-git-send-email-tytso@mit.edu> References: <1407604220-2620-1-git-send-email-tytso@mit.edu> Cc: antymat+debian@chelmska.waw.pl, 756922@bugs.debian.org, Theodore Ts'o To: Ext4 Developers List Return-path: Received: from imap.thunk.org ([74.207.234.97]:52422 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbaHIRK1 (ORCPT ); Sat, 9 Aug 2014 13:10:27 -0400 In-Reply-To: <1407604220-2620-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 Reported-by: Marcin Wolcendorf Signed-off-by: Theodore Ts'o --- resize/resize2fs.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/resize/resize2fs.c b/resize/resize2fs.c index 9641b1e..b3755f6 100644 --- a/resize/resize2fs.c +++ b/resize/resize2fs.c @@ -489,6 +489,13 @@ 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; + } + /* * Update the location of the backup superblocks if the * sparse_super2 feature is enabled. @@ -998,13 +1005,15 @@ 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; - } retval = reserve_sparse_super2_last_group(rfs, meta_bmap); if (retval) -- 2.0.0