+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;
+
+ space = sdp->sd_heightsize[x - 1] * sdp->sd_inptrs;
+ d = space;
+ m = do_div(d, sdp->sd_inptrs);
+
+ if (d != sdp->sd_heightsize[x - 1] || m)
+ break;
+ sdp->sd_heightsize[x] = space;
+ }
+ sdp->sd_max_height = x;
+ sdp->sd_heightsize[x] = ~0;
+ gfs2_assert(sdp, sdp->sd_max_height <= GFS2_MAX_META_HEIGHT);
+
+ sdp->sd_jheightsize[0] = sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_dinode);
+ sdp->sd_jheightsize[1] = sdp->sd_jbsize * sdp->sd_diptrs;
+ for (x = 2;; x++) {
+ u64 space, d;
+ u32 m;
+
+ space = sdp->sd_jheightsize[x - 1] * sdp->sd_inptrs;
+ d = space;
+ m = do_div(d, sdp->sd_inptrs);
+
+ if (d != sdp->sd_jheightsize[x - 1] || m)
+ break;
+ sdp->sd_jheightsize[x] = space;
+ }
+ sdp->sd_max_jheight = x;
+ sdp->sd_jheightsize[x] = ~0;
+ gfs2_assert(sdp, sdp->sd_max_jheight <= GFS2_MAX_META_HEIGHT);
+
+ return 0;