From 69f7c80eaf25a642b0eb85f4557605c89acd80b6 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 18 May 2009 17:02:32 -0500 Subject: [PATCH] resize2fs: fix minimum size calculations The extra padding added to the minimum size calculations: /* * We need to reserve a few extra blocks if extents are * enabled, in case we need to grow the extent tree. The more * we shrink the file system, the more space we need. */ if (fs->super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_EXTENTS) blks_needed += (fs->super->s_blocks_count - blks_needed)/500; can go quite wrong if we've already added up more "blks_needed" than our current size, and the above subtraction wraps. This can easily happen for a filesystem which is almost completely full. In this case, just return the current fs size as the minimum and be done with it. With this fix we could probably call calculate_minimum_resize_size() for each resize2fs invocation and refuse to resize smaller than that? Signed-off-by: Eric Sandeen Signed-off-by: Theodore Ts'o --- resize/resize2fs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/resize/resize2fs.c b/resize/resize2fs.c index f3e7fd0..0d5dc81 100644 --- a/resize/resize2fs.c +++ b/resize/resize2fs.c @@ -2003,6 +2003,12 @@ blk_t calculate_minimum_resize_size(ext2_filsys fs) blks_needed += overhead; /* + * If at this point we've already added up more "needed" than + * the current size, just return current size as minimum. + */ + if (blks_needed >= fs->super->s_blocks_count) + return fs->super->s_blocks_count; + /* * We need to reserve a few extra blocks if extents are * enabled, in case we need to grow the extent tree. The more * we shrink the file system, the more space we need. -- 1.8.3.1