-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Wed, 3 Dec 2008 17:53:43 -0500 "Josh Carroll" <josh.carr...@gmail.com> mentioned:
> > Ok, I describe my concern once more. I do not object against the checking > > of the inode size. But, if inode size is changed, then some data is added > > to the inode, that could (and usually does, otherwise why extend it ?) > > change intrerpetation of the inode. Thus, we need a verification of the > > fact that simply ignoring added fields does not damage filesystem or > > cause user data corruption. Verification != testing. > > Let me take another crack at explaining why I think this patch is not > dangerous. > > The inode size is determined by reading the following member: > > __u16 s_inode_size; > > of the ext2_super_block structure. > > I took a look at the Linux 2.6.27.7 kernel source, and indeed they do > something very similar if not the same: > > #define EXT2_INODE_SIZE(s) (EXT2_SB(s)->s_inode_size) > > If you compare to what I did: > > #define EXT2_INODE_SIZE(s) ((s)->u.ext2_sb.s_inode_size) > > This is really the same thing, since EXT2_SB is defined (in the Linux > kernel src as): > > #ifdef __KERNEL__ > #include <linux/ext2_fs_sb.h> > static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb) > { > return sb->s_fs_info; > } > > And struct ext2_sb_info has the following member: > > int s_inode_size; > > Essentially, the changes I made simply query the existing information > from the filesystem, which is what the Linux kernel does as well. > > The inode size, blocks per group, etc are all defined at filesystem > creation time by mke2fs and it ensures the sanity of the relationship > between the inodes/blocks/block groups. > > The first diagram here: > > http://sunsite.nus.sg/LDP/LDP/tlk/node95.html > > Makes it clear that as long as the number of inodes per block and the > blocks per group is is sane during fs creation, looking up the inode > size as my patch does is fine, since the creation of the filesystem is > ensures a correct by construction situation. We're simply reading the > size of the inode based on the filesystem. > > I hope this is sufficient to convince some further thought about > committing this. > > For those interested in the relevant Linux kernel source, you can have > a look at line 105 of include/linux/ext2_fs.h from the linux-2.6.27.7 > kernel source. > Hi Josh! I've commited the similar patch today that should be fixing your problem. Can you check this, please? Sorry I've missed this thread in the first place. - -- Stanislav Sedov ST4096-RIPE -----BEGIN PGP SIGNATURE----- iEYEARECAAYFAklzYsoACgkQK/VZk+smlYF3ZwCeOyVUdzrKOdu4Pg3ztAZ0QQaY GGIAnA+oL054T0EAajbfwpYSTDRKVISC =jJFT -----END PGP SIGNATURE----- !DSPAM:497362c8967002668918391! _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"