libext2fs: Add support for uninit_bg feature to allocation functions

If the allocation functions need to allocate out of a block group
where the inode and/or block bitmaps have not yet been initialized,
initialize them so ext2fs_new_block() and ext2fs_new_inode() work
correctly.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/alloc.c b/lib/ext2fs/alloc.c
index f8d8a5f..ebe2bf6 100644 (file)
--- a/lib/ext2fs/alloc.c
+++ b/lib/ext2fs/alloc.c
@@ -27,6 +27,74 @@
 #include "ext2fs.h"
 
 /*
+ * Check for uninit block bitmaps and deal with them appropriately
+ */
+static check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
+                         dgrp_t group)
+{
+       int             i;
+       blk_t           blk, super_blk, old_desc_blk, new_desc_blk;
+       int             old_desc_blocks;
+
+       if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
+           !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT))
+               return;
+
+       blk = (group * fs->super->s_blocks_per_group) +
+               fs->super->s_first_data_block;
+
+       ext2fs_super_and_bgd_loc(fs, group, &super_blk,
+                                &old_desc_blk, &new_desc_blk, 0);
+
+       if (fs->super->s_feature_incompat &
+           EXT2_FEATURE_INCOMPAT_META_BG)
+               old_desc_blocks = fs->super->s_first_meta_bg;
+       else
+               old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
+
+       for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
+               if ((blk == super_blk) ||
+                   (old_desc_blk && old_desc_blocks &&
+                    (blk >= old_desc_blk) &&
+                    (blk < old_desc_blk + old_desc_blocks)) ||
+                   (new_desc_blk && (blk == new_desc_blk)) ||
+                   (blk == fs->group_desc[group].bg_block_bitmap) ||
+                   (blk == fs->group_desc[group].bg_inode_bitmap) ||
+                   (blk >= fs->group_desc[group].bg_inode_table &&
+                    (blk < fs->group_desc[group].bg_inode_table
+                     + fs->inode_blocks_per_group)))
+                       ext2fs_fast_mark_block_bitmap(map, blk);
+               else
+                       ext2fs_fast_unmark_block_bitmap(map, blk);
+       }
+       fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
+       ext2fs_group_desc_csum_set(fs, group);
+}
+
+/*
+ * Check for uninit inode bitmaps and deal with them appropriately
+ */
+static check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
+                         dgrp_t group)
+{
+       int             i;
+       ext2_ino_t      ino;
+
+       if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
+                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
+           !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT))
+               return;
+
+       ino = (group * fs->super->s_inodes_per_group) + 1;
+       for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
+               ext2fs_fast_unmark_inode_bitmap(map, ino);
+
+       fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT;
+       check_block_uninit(fs, fs->block_map, group);
+}
+
+/*
  * Right now, just search forward from the parent directory's block
  * group to find the next free inode.
  *
@@ -56,6 +124,10 @@ errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
        i = start_inode;
 
        do {
+               if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
+                       check_inode_uninit(fs, map, (i - 1) /
+                                          EXT2_INODES_PER_GROUP(fs->super));
+
                if (!ext2fs_fast_test_inode_bitmap(map, i))
                        break;
                i++;
@@ -87,7 +159,16 @@ errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
        if (!goal || (goal >= fs->super->s_blocks_count))
                goal = fs->super->s_first_data_block;
        i = goal;
+       check_block_uninit(fs, map,
+                          (i - fs->super->s_first_data_block) /
+                          EXT2_BLOCKS_PER_GROUP(fs->super));
        do {
+               if (((i - fs->super->s_first_data_block) %
+                    EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
+                       check_block_uninit(fs, map,
+                                          (i - fs->super->s_first_data_block) /
+                                          EXT2_BLOCKS_PER_GROUP(fs->super));
+
                if (!ext2fs_fast_test_block_bitmap(map, i)) {
                        *ret = i;
                        return 0;