Many files:

[thirdparty/e2fsprogs.git] / lib / ext2fs / closefs.c

diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index e24b6b6972644e72068d067b2cd66a5666eac826..a61f87831f1b5e87e255cda83ca54f35b1f4710f 100644 (file)
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -22,6 +22,38 @@
 
 #include "ext2fsP.h"
 
+static int test_root(int a, int b)
+{
+       if (a == 0)
+               return 1;
+       while (1) {
+               if (a == 1)
+                       return 1;
+               if (a % b)
+                       return 0;
+               a = a / b;
+       }
+}
+
+int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
+{
+#ifdef EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER
+       struct ext2fs_sb        *s;
+
+       s = (struct ext2fs_sb *) fs->super;
+       if (!(s->s_feature_ro_compat & EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER))
+               return 1;
+
+       if (test_root(group_block, 3) || (test_root(group_block, 5)) ||
+           test_root(group_block, 7))
+               return 1;
+       
+       return 0;
+#else
+       return 1;
+#endif
+}
+
 errcode_t ext2fs_flush(ext2_filsys fs)
 {
        int             i,j,maxgroup;
@@ -92,6 +124,9 @@ errcode_t ext2fs_flush(ext2_filsys fs)
        maxgroup = (fs->flags & EXT2_FLAG_MASTER_SB_ONLY) ? 1 :
                fs->group_desc_count;
        for (i = 0; i < maxgroup; i++) {
+               if (!ext2fs_bg_has_super(fs, i))
+                       goto next_group;
+
                if (i !=0 ) {
                        retval = io_channel_write_blk(fs->io, group_block,
                                                      -SUPERBLOCK_SIZE,
@@ -108,6 +143,7 @@ errcode_t ext2fs_flush(ext2_filsys fs)
                                goto errout;
                        group_ptr += fs->blocksize;
                }
+       next_group:
                group_block += EXT2_BLOCKS_PER_GROUP(fs->super);
        }