From: Felipe Franciosi <ozzy@doc.ic.ac.uk>
Subject: Simple inode question (ext2/3)
Date: Tue, 24 Feb 2009 17:13:52 +0000 (GMT)
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Hi there!

I've been trying to write a kernel module that is capable of locating a specific mounted filesystem (ext2/3) and dump all the inode entries that are in use. I have two questions:

1) Is it possible to know if an inode is free just by looking to its (struct ext3_inode) info or do I have to check the inode bitmap for the specific block group?

2) Does the following look correct?

--------8<--------

struct vfsmount        *mountpoint = ... // fetch this from the proper namespace
struct ext3_sb_info    *sbi = EXT3_SB(mountpoint->mnt_sb);
struct ext3_group_desc *egd;
struct ext3_inode      *ino;
struct buffer_head     *bh;
int i, j, k;

for (i=0; i<sbi->s_groups_count; i++) {
 egd = ext3_get_group_desc(mountpoint->mnt_sb, i, NULL);
 for (j=0; j<(sbi->s_inodes_per_group)/(sbi->s_inodes_per_block); j++) {
  bh = sb_getblk(mountpoint->mnt_sb, le32_to_cpu(egd->bg_inode_table+j));
  for (k=0; k<sbi->s_inodes_per_block; k++) {
   ino = (struct ext3_inode *)(bh+(k*sizeof(struct ext3_inode)));
   // dump contents of ino
   // index of ino should be: (i*(sbi->s_inodes_per_group)) + (j*(sbi->s_inodes_per_block)) + k
  }
 }
}

--------8<--------

Cheers,
Felipe