Ted, this was sent with the first patch, and it looks like it is a very serious problem. Looking through the e2fsck code it would also seem possible to move the setting of EXT2_FLAG_MASTER_SB_ONLY before the journal replay. That is the second patch. I'm not sure which one is better. Jim Garlick wrote: > When fsck replays the journal, it clears the EXT3_FEATURE_INCOMPAT_RECOVER > feature, dirties the superblock, and closes the file system. > Unfortunately, the file system EXT2_FLAG_MASTER_SB_ONLY flag is not set > at this time, so it copies the primary superblock and group descriptors > over all the backups. Then fsck restarts and checks the superblock for > consistancy. If the superblock or group descriptors are then found to > be bad, all your backups are now also bad. Index: e2fsprogs+chaos/lib/ext2fs/openfs.c =================================================================== --- e2fsprogs+chaos.orig/lib/ext2fs/openfs.c +++ e2fsprogs+chaos/lib/ext2fs/openfs.c @@ -101,6 +101,8 @@ errcode_t ext2fs_open2(const char *name, memset(fs, 0, sizeof(struct struct_ext2_filsys)); fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS; fs->flags = flags; + /* don't overwrite sb backups unless flag is explicitly cleared */ + fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; fs->umask = 022; retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name); if (retval) --------------------------------------------------------------------------- Index: e2fsprogs/e2fsck/unix.c =================================================================== --- e2fsprogs.orig/e2fsck/unix.c 2006-12-27 17:12:23.000000000 -0700 +++ e2fsprogs/e2fsck/unix.c 2007-02-08 22:05:13.000000000 -0700 @@ -1153,6 +1153,15 @@ restart: } /* + * We only update the master superblock because (a) paranoia; + * we don't want to corrupt the backup superblocks, and (b) we + * don't need to update the mount count and last checked + * fields in the backup superblock (the kernel doesn't + * update the backup superblocks anyway). + */ + fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; + + /* * Check to see if we need to do ext3-style recovery. If so, * do it, and then restart the fsck. */ @@ -1227,15 +1236,6 @@ restart: !(ctx->options & E2F_OPT_READONLY)) ext2fs_mark_super_dirty(fs); - /* - * We only update the master superblock because (a) paranoia; - * we don't want to corrupt the backup superblocks, and (b) we - * don't need to update the mount count and last checked - * fields in the backup superblock (the kernel doesn't - * update the backup superblocks anyway). - */ - fs->flags |= EXT2_FLAG_MASTER_SB_ONLY; - ehandler_init(fs->io); if (ctx->superblock) Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
