Add 64-bit closefs interface

Add new ext2fs_super_and_bgd_loc2() that returns blk64_t pointers.
The function now returns the number of blocks used by super block and
group descriptors since with flex_bg, it can no longer be assumed that
bitmaps and inode tables still resided within the block group.

Signed-off-by: Jose R. Santos <jrs@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/closefs.c b/lib/ext2fs/closefs.c
index ed7109e..4261268 100644 (file)
--- a/lib/ext2fs/closefs.c
+++ b/lib/ext2fs/closefs.c
@@ -46,31 +46,33 @@ int ext2fs_bg_has_super(ext2_filsys fs, int group_block)
 }
 
 /*
- * This function returns the location of the superblock, block group
- * descriptors for a given block group.  It currently returns the
- * number of free blocks assuming that inode table and allocation
- * bitmaps will be in the group.  This is not necessarily the case
- * when the flex_bg feature is enabled, so callers should take care!
- * It was only really intended for use by mke2fs, and even there it's
- * not that useful.  In the future, when we redo this function for
- * 64-bit block numbers, we should probably return the number of
- * blocks used by the super block and group descriptors instead.
+ * ext2fs_super_and_bgd_loc2()
+ * @fs:                        ext2 fs pointer
+ * @group              given block group
+ * @ret_super_blk:     if !NULL, returns super block location
+ * @ret_old_desc_blk:  if !NULL, returns location of the old block
+ *                     group descriptor
+ * @ret_new_desc_blk:  if !NULL, returns location of meta_bg block
+ *                     group descriptor
+ * @ret_used_blks:     if !NULL, returns number of blocks used by
+ *                     super block and group_descriptors.
  *
- * See also the comment for ext2fs_reserve_super_and_bgd()
+ * Returns errcode_t of 0
  */
-int ext2fs_super_and_bgd_loc(ext2_filsys fs,
-                            dgrp_t group,
-                            blk_t *ret_super_blk,
-                            blk_t *ret_old_desc_blk,
-                            blk_t *ret_new_desc_blk,
-                            int *ret_meta_bg)
+errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
+                                          dgrp_t group,
+                                          blk64_t *ret_super_blk,
+                                          blk64_t *ret_old_desc_blk,
+                                          blk64_t *ret_new_desc_blk,
+                                          blk_t *ret_used_blks)
 {
-       blk_t   group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
+       blk64_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0;
        unsigned int meta_bg, meta_bg_size;
-       blk_t   numblocks, old_desc_blocks;
+       blk_t   numblocks = 0;
+       blk64_t old_desc_blocks;
        int     has_super;
 
-       group_block = ext2fs_group_first_block(fs, group);
+       group_block = ext2fs_group_first_block2(fs, group);
 
        if (fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG)
                old_desc_blocks = fs->super->s_first_meta_bg;
@@ -78,20 +80,11 @@ int ext2fs_super_and_bgd_loc(ext2_filsys fs,
                old_desc_blocks =
                        fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
 
-       if (group == fs->group_desc_count-1) {
-               numblocks = (fs->super->s_blocks_count -
-                            fs->super->s_first_data_block) %
-                       fs->super->s_blocks_per_group;
-               if (!numblocks)
-                       numblocks = fs->super->s_blocks_per_group;
-       } else
-               numblocks = fs->super->s_blocks_per_group;
-
        has_super = ext2fs_bg_has_super(fs, group);
 
        if (has_super) {
                super_blk = group_block;
-               numblocks--;
+               numblocks++;
        }
        meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
        meta_bg = group / meta_bg_size;
@@ -100,7 +93,7 @@ int ext2fs_super_and_bgd_loc(ext2_filsys fs,
            (meta_bg < fs->super->s_first_meta_bg)) {
                if (has_super) {
                        old_desc_blk = group_block + 1;
-                       numblocks -= old_desc_blocks;
+                       numblocks += old_desc_blocks;
                }
        } else {
                if (((group % meta_bg_size) == 0) ||
@@ -109,23 +102,78 @@ int ext2fs_super_and_bgd_loc(ext2_filsys fs,
                        if (has_super)
                                has_super = 1;
                        new_desc_blk = group_block + has_super;
-                       numblocks--;
+                       numblocks++;
                }
        }
 
-       numblocks -= 2 + fs->inode_blocks_per_group;
-
        if (ret_super_blk)
                *ret_super_blk = super_blk;
        if (ret_old_desc_blk)
                *ret_old_desc_blk = old_desc_blk;
        if (ret_new_desc_blk)
                *ret_new_desc_blk = new_desc_blk;
-       if (ret_meta_bg)
-               *ret_meta_bg = meta_bg;
-       return (numblocks);
+       if (ret_used_blks)
+               *ret_used_blks = numblocks;
+
+       return 0;
 }
 
+/*
+ * This function returns the location of the superblock, block group
+ * descriptors for a given block group.  It currently returns the
+ * number of free blocks assuming that inode table and allocation
+ * bitmaps will be in the group.  This is not necessarily the case
+ * when the flex_bg feature is enabled, so callers should take care!
+ * It was only really intended for use by mke2fs, and even there it's
+ * not that useful.
+ *
+ * The ext2fs_super_and_bgd_loc2() function is 64-bit block number
+ * capable and returns the number of blocks used by super block and
+ * group descriptors.
+ */
+int ext2fs_super_and_bgd_loc(ext2_filsys fs,
+                            dgrp_t group,
+                            blk_t *ret_super_blk,
+                            blk_t *ret_old_desc_blk,
+                            blk_t *ret_new_desc_blk,
+                            int *ret_meta_bg)
+{
+       blk64_t ret_super_blk2;
+       blk64_t ret_old_desc_blk2;
+       blk64_t ret_new_desc_blk2;
+       blk_t ret_used_blks;
+       blk_t numblocks;
+       unsigned int meta_bg_size;
+
+       ext2fs_super_and_bgd_loc2(fs, group, &ret_super_blk2,
+                                       &ret_old_desc_blk2,
+                                       &ret_new_desc_blk2,
+                                       &ret_used_blks);
+
+       if (group == fs->group_desc_count-1) {
+               numblocks = (fs->super->s_blocks_count -
+                            fs->super->s_first_data_block) %
+                       fs->super->s_blocks_per_group;
+               if (!numblocks)
+                       numblocks = fs->super->s_blocks_per_group;
+       } else
+               numblocks = fs->super->s_blocks_per_group;
+
+       if (ret_super_blk)
+               *ret_super_blk = (blk_t)ret_super_blk2;
+       if (ret_old_desc_blk)
+               *ret_old_desc_blk = (blk_t)ret_old_desc_blk2;
+       if (ret_new_desc_blk)
+               *ret_new_desc_blk = (blk_t)ret_new_desc_blk2;
+       if (ret_meta_bg) {
+               meta_bg_size = EXT2_DESC_PER_BLOCK(fs->super);
+               *ret_meta_bg = group / meta_bg_size;
+       }
+
+       numblocks -= 2 + fs->inode_blocks_per_group + ret_used_blks;
+
+       return numblocks;
+}
 
 /*
  * This function forces out the primary superblock.  We need to only

diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 92ce9f4..5fd5126 100644 (file)
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -798,6 +798,12 @@ extern errcode_t ext2fs_check_desc(ext2_filsys fs);
 extern errcode_t ext2fs_close(ext2_filsys fs);
 extern errcode_t ext2fs_flush(ext2_filsys fs);
 extern int ext2fs_bg_has_super(ext2_filsys fs, int group_block);
+extern errcode_t ext2fs_super_and_bgd_loc2(ext2_filsys fs,
+                                   dgrp_t group,
+                                   blk64_t *ret_super_blk,
+                                   blk64_t *ret_old_desc_blk,
+                                   blk64_t *ret_new_desc_blk,
+                                   blk_t *ret_used_blks);
 extern int ext2fs_super_and_bgd_loc(ext2_filsys fs,
                                    dgrp_t group,
                                    blk_t *ret_super_blk,