resize2fs: fix minimum resize size calculation with flex_bg

When flex_bg is on, calculate_minimum_resize_size() should add more meta
blocks for newly added flex_bg.

Addresses-RedHat-Bugzilla: #519131
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/resize/resize2fs.c b/resize/resize2fs.c
index c0b00b6..648e1f9 100644 (file)
--- a/resize/resize2fs.c
+++ b/resize/resize2fs.c
@@ -1900,6 +1900,8 @@ blk_t calculate_minimum_resize_size(ext2_filsys fs)
        blk_t inode_count, blks_needed, groups, data_blocks;
        blk_t grp, data_needed, last_start;
        int overhead = 0, num_of_superblocks = 0;
+       int extra_groups = 0;
+       int flexbg_size = 1 << fs->super->s_log_groups_per_flex;
 
        /*
         * first figure out how many group descriptors we need to
@@ -1934,11 +1936,9 @@ blk_t calculate_minimum_resize_size(ext2_filsys fs)
                 * of inode tables of slack space so the resize
                 * operation can be guaranteed to finish.
                 */
-               int flexbg_size = 1 << fs->super->s_log_groups_per_flex;
-               int extra_groups;
-
                extra_groups = flexbg_size - (groups & (flexbg_size - 1));
                data_needed += META_OVERHEAD(fs) * extra_groups;
+               extra_groups = groups % flexbg_size;
        }
 
        /*
@@ -2002,6 +2002,20 @@ blk_t calculate_minimum_resize_size(ext2_filsys fs)
                }
 
                groups += extra_grps;
+               extra_groups += extra_grps;
+               if (fs->super->s_feature_incompat
+                       & EXT4_FEATURE_INCOMPAT_FLEX_BG
+                   && extra_groups > flexbg_size) {
+                       /*
+                        * For ext4 we need to allow for up to a flex_bg worth
+                        * of inode tables of slack space so the resize
+                        * operation can be guaranteed to finish.
+                        */
+                       extra_groups = flexbg_size -
+                                               (groups & (flexbg_size - 1));
+                       data_needed += META_OVERHEAD(fs) * extra_groups;
+                       extra_groups = groups % flexbg_size;
+               }
        }
 
        /* now for the fun voodoo */