+ if (sb->sb_magic != GFS2_MAGIC ||
+ sb->sb_type != GFS2_METATYPE_SB) {
+ if (!silent)
+ printk(KERN_WARNING "GFS2: not a GFS2 filesystem\n");
+ return -EINVAL;
+ }
+
+ /* If format numbers match exactly, we're done. */
+
+ if (sb->sb_fs_format == GFS2_FORMAT_FS &&
+ sb->sb_multihost_format == GFS2_FORMAT_MULTI)
+ return 0;
+
+ if (sb->sb_fs_format != GFS2_FORMAT_FS) {
+ for (x = 0; gfs2_old_fs_formats[x]; x++)
+ if (gfs2_old_fs_formats[x] == sb->sb_fs_format)
+ break;
+
+ if (!gfs2_old_fs_formats[x]) {
+ printk(KERN_WARNING
+ "GFS2: code version (%u, %u) is incompatible "
+ "with ondisk format (%u, %u)\n",
+ GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+ sb->sb_fs_format, sb->sb_multihost_format);
+ printk(KERN_WARNING
+ "GFS2: I don't know how to upgrade this FS\n");
+ return -EINVAL;
+ }
+ }
+
+ if (sb->sb_multihost_format != GFS2_FORMAT_MULTI) {
+ for (x = 0; gfs2_old_multihost_formats[x]; x++)
+ if (gfs2_old_multihost_formats[x] ==
+ sb->sb_multihost_format)
+ break;
+
+ if (!gfs2_old_multihost_formats[x]) {
+ printk(KERN_WARNING
+ "GFS2: code version (%u, %u) is incompatible "
+ "with ondisk format (%u, %u)\n",
+ GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+ sb->sb_fs_format, sb->sb_multihost_format);
+ printk(KERN_WARNING
+ "GFS2: I don't know how to upgrade this FS\n");
+ return -EINVAL;
+ }
+ }
+
+ if (!sdp->sd_args.ar_upgrade) {
+ printk(KERN_WARNING
+ "GFS2: code version (%u, %u) is incompatible "
+ "with ondisk format (%u, %u)\n",
+ GFS2_FORMAT_FS, GFS2_FORMAT_MULTI,
+ sb->sb_fs_format, sb->sb_multihost_format);
+ printk(KERN_INFO
+ "GFS2: Use the \"upgrade\" mount option to upgrade "
+ "the FS\n");
+ printk(KERN_INFO "GFS2: See the manual for more details\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void end_bio_io_page(struct bio *bio, int error)
+{
+ struct page *page = bio->bi_private;
+
+ if (!error)
+ SetPageUptodate(page);
+ else
+ printk(KERN_WARNING "gfs2: error %d reading superblock\n", error);
+ unlock_page(page);
+}
+
+static void gfs2_sb_in(struct gfs2_sb_host *sb, const void *buf)
+{
+ const struct gfs2_sb *str = buf;
+
+ sb->sb_magic = be32_to_cpu(str->sb_header.mh_magic);
+ sb->sb_type = be32_to_cpu(str->sb_header.mh_type);
+ sb->sb_format = be32_to_cpu(str->sb_header.mh_format);
+ sb->sb_fs_format = be32_to_cpu(str->sb_fs_format);
+ sb->sb_multihost_format = be32_to_cpu(str->sb_multihost_format);
+ sb->sb_bsize = be32_to_cpu(str->sb_bsize);
+ sb->sb_bsize_shift = be32_to_cpu(str->sb_bsize_shift);
+ sb->sb_master_dir.no_addr = be64_to_cpu(str->sb_master_dir.no_addr);
+ sb->sb_master_dir.no_formal_ino = be64_to_cpu(str->sb_master_dir.no_formal_ino);
+ sb->sb_root_dir.no_addr = be64_to_cpu(str->sb_root_dir.no_addr);
+ sb->sb_root_dir.no_formal_ino = be64_to_cpu(str->sb_root_dir.no_formal_ino);
+
+ memcpy(sb->sb_lockproto, str->sb_lockproto, GFS2_LOCKNAME_LEN);
+ memcpy(sb->sb_locktable, str->sb_locktable, GFS2_LOCKNAME_LEN);
+ memcpy(sb->sb_uuid, str->sb_uuid, 16);
+}
+
+/**
+ * gfs2_read_super - Read the gfs2 super block from disk
+ * @sdp: The GFS2 super block
+ * @sector: The location of the super block
+ * @error: The error code to return
+ *
+ * This uses the bio functions to read the super block from disk
+ * because we want to be 100% sure that we never read cached data.
+ * A super block is read twice only during each GFS2 mount and is
+ * never written to by the filesystem. The first time its read no
+ * locks are held, and the only details which are looked at are those
+ * relating to the locking protocol. Once locking is up and working,
+ * the sb is read again under the lock to establish the location of
+ * the master directory (contains pointers to journals etc) and the
+ * root directory.
+ *
+ * Returns: 0 on success or error
+ */
+
+static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector)
+{
+ struct super_block *sb = sdp->sd_vfs;
+ struct gfs2_sb *p;
+ struct page *page;
+ struct bio *bio;
+
+ page = alloc_page(GFP_NOFS);
+ if (unlikely(!page))
+ return -ENOBUFS;
+
+ ClearPageUptodate(page);
+ ClearPageDirty(page);
+ lock_page(page);
+
+ bio = bio_alloc(GFP_NOFS, 1);
+ bio->bi_sector = sector * (sb->s_blocksize >> 9);
+ bio->bi_bdev = sb->s_bdev;
+ bio_add_page(bio, page, PAGE_SIZE, 0);
+
+ bio->bi_end_io = end_bio_io_page;
+ bio->bi_private = page;
+ submit_bio(READ_SYNC | (1 << BIO_RW_META), bio);
+ wait_on_page_locked(page);
+ bio_put(bio);
+ if (!PageUptodate(page)) {
+ __free_page(page);
+ return -EIO;
+ }
+ p = kmap(page);
+ gfs2_sb_in(&sdp->sd_sb, p);
+ kunmap(page);
+ __free_page(page);
+ return 0;
+}
+
+/**
+ * gfs2_read_sb - Read super block
+ * @sdp: The GFS2 superblock
+ * @silent: Don't print message if mount fails
+ *
+ */
+
+static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)
+{
+ u32 hash_blocks, ind_blocks, leaf_blocks;
+ u32 tmp_blocks;
+ unsigned int x;
+ int error;
+
+ error = gfs2_read_super(sdp, GFS2_SB_ADDR >> sdp->sd_fsb2bb_shift);
+ if (error) {
+ if (!silent)
+ fs_err(sdp, "can't read superblock\n");
+ return error;
+ }
+
+ error = gfs2_check_sb(sdp, &sdp->sd_sb, silent);
+ if (error)
+ return error;
+
+ sdp->sd_fsb2bb_shift = sdp->sd_sb.sb_bsize_shift -
+ GFS2_BASIC_BLOCK_SHIFT;
+ sdp->sd_fsb2bb = 1 << sdp->sd_fsb2bb_shift;
+ sdp->sd_diptrs = (sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_dinode)) / sizeof(u64);
+ sdp->sd_inptrs = (sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_meta_header)) / sizeof(u64);
+ sdp->sd_jbsize = sdp->sd_sb.sb_bsize - sizeof(struct gfs2_meta_header);
+ sdp->sd_hash_bsize = sdp->sd_sb.sb_bsize / 2;
+ sdp->sd_hash_bsize_shift = sdp->sd_sb.sb_bsize_shift - 1;
+ sdp->sd_hash_ptrs = sdp->sd_hash_bsize / sizeof(u64);
+ sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_meta_header)) /
+ sizeof(struct gfs2_quota_change);
+
+ /* Compute maximum reservation required to add a entry to a directory */
+
+ hash_blocks = DIV_ROUND_UP(sizeof(u64) * (1 << GFS2_DIR_MAX_DEPTH),
+ sdp->sd_jbsize);
+
+ ind_blocks = 0;
+ for (tmp_blocks = hash_blocks; tmp_blocks > sdp->sd_diptrs;) {
+ tmp_blocks = DIV_ROUND_UP(tmp_blocks, sdp->sd_inptrs);
+ ind_blocks += tmp_blocks;
+ }
+
+ leaf_blocks = 2 + GFS2_DIR_MAX_DEPTH;
+
+ sdp->sd_max_dirres = hash_blocks + ind_blocks + leaf_blocks;
+
+ sdp->sd_heightsize[0] = sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_dinode);
+ sdp->sd_heightsize[1] = sdp->sd_sb.sb_bsize * sdp->sd_diptrs;
+ for (x = 2;; x++) {
+ u64 space, d;
+ u32 m;