+static void pass1_readahead(e2fsck_t ctx, dgrp_t *group, ext2_ino_t *next_ino)
+{
+ ext2_ino_t inodes_in_group = 0, inodes_per_block, inodes_per_buffer;
+ dgrp_t start = *group, grp;
+ blk64_t blocks_to_read = 0;
+ errcode_t err = EXT2_ET_INVALID_ARGUMENT;
+
+ if (ctx->readahead_kb == 0)
+ goto out;
+
+ /* Keep iterating groups until we have enough to readahead */
+ inodes_per_block = EXT2_INODES_PER_BLOCK(ctx->fs->super);
+ for (grp = start; grp < ctx->fs->group_desc_count; grp++) {
+ if (ext2fs_bg_flags_test(ctx->fs, grp, EXT2_BG_INODE_UNINIT))
+ continue;
+ inodes_in_group = ctx->fs->super->s_inodes_per_group -
+ ext2fs_bg_itable_unused(ctx->fs, grp);
+ blocks_to_read += (inodes_in_group + inodes_per_block - 1) /
+ inodes_per_block;
+ if (blocks_to_read * ctx->fs->blocksize >
+ ctx->readahead_kb * 1024)
+ break;
+ }
+
+ err = e2fsck_readahead(ctx->fs, E2FSCK_READA_ITABLE, start,
+ grp - start + 1);
+ if (err == EAGAIN) {
+ ctx->readahead_kb /= 2;
+ err = 0;
+ }
+
+out:
+ if (err) {
+ /* Error; disable itable readahead */
+ *group = ctx->fs->group_desc_count;
+ *next_ino = ctx->fs->super->s_inodes_count;
+ } else {
+ /*
+ * Don't do more readahead until we've reached the first inode
+ * of the last inode scan buffer block for the last group.
+ */
+ *group = grp + 1;
+ inodes_per_buffer = (ctx->inode_buffer_blocks ?
+ ctx->inode_buffer_blocks :
+ EXT2_INODE_SCAN_DEFAULT_BUFFER_BLOCKS) *
+ ctx->fs->blocksize /
+ EXT2_INODE_SIZE(ctx->fs->super);
+ inodes_in_group--;
+ *next_ino = inodes_in_group -
+ (inodes_in_group % inodes_per_buffer) + 1 +
+ (grp * ctx->fs->super->s_inodes_per_group);
+ }
+}
+
+/*
+ * Check if the passed ino is one of the used superblock quota inodes.
+ *
+ * Before the quota inodes were journaled, older superblock quota inodes
+ * were just regular files in the filesystem and not reserved inodes. This
+ * checks if the passed ino is one of the s_*_quota_inum superblock fields,
+ * which may not always be the same as the EXT4_*_QUOTA_INO fields.
+ */
+static int quota_inum_is_super(struct ext2_super_block *sb, ext2_ino_t ino)
+{
+ enum quota_type qtype;
+
+ for (qtype = 0; qtype < MAXQUOTAS; qtype++)
+ if (*quota_sb_inump(sb, qtype) == ino)
+ return 1;
+
+ return 0;
+}
+
+/*
+ * Check if the passed ino is one of the reserved quota inodes.
+ * This checks if the inode number is one of the reserved EXT4_*_QUOTA_INO
+ * inodes. These inodes may or may not be in use by the quota feature.
+ */
+static int quota_inum_is_reserved(ext2_filsys fs, ext2_ino_t ino)
+{
+ enum quota_type qtype;
+
+ for (qtype = 0; qtype < MAXQUOTAS; qtype++)
+ if (quota_type2inum(qtype, fs->super) == ino)
+ return 1;
+
+ return 0;
+}
+