super.c

linux 内核源代码

	int qtype;
	char *qname;
#endif

	if (!options)
		return 1;

	while ((p = strsep (&options, ",")) != NULL) {
		int token;
		if (!*p)
			continue;

		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_bsd_df:
			clear_opt (sbi->s_mount_opt, MINIX_DF);
			break;
		case Opt_minix_df:
			set_opt (sbi->s_mount_opt, MINIX_DF);
			break;
		case Opt_grpid:
			set_opt (sbi->s_mount_opt, GRPID);
			break;
		case Opt_nogrpid:
			clear_opt (sbi->s_mount_opt, GRPID);
			break;
		case Opt_resuid:
			if (match_int(&args[0], &option))
				return 0;
			sbi->s_resuid = option;
			break;
		case Opt_resgid:
			if (match_int(&args[0], &option))
				return 0;
			sbi->s_resgid = option;
			break;
		case Opt_sb:
			/* handled by get_sb_block() instead of here */
			/* *sb_block = match_int(&args[0]); */
			break;
		case Opt_err_panic:
			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
			clear_opt (sbi->s_mount_opt, ERRORS_RO);
			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
			break;
		case Opt_err_ro:
			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
			set_opt (sbi->s_mount_opt, ERRORS_RO);
			break;
		case Opt_err_cont:
			clear_opt (sbi->s_mount_opt, ERRORS_RO);
			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
			set_opt (sbi->s_mount_opt, ERRORS_CONT);
			break;
		case Opt_nouid32:
			set_opt (sbi->s_mount_opt, NO_UID32);
			break;
		case Opt_nocheck:
			clear_opt (sbi->s_mount_opt, CHECK);
			break;
		case Opt_debug:
			set_opt (sbi->s_mount_opt, DEBUG);
			break;
		case Opt_oldalloc:
			set_opt (sbi->s_mount_opt, OLDALLOC);
			break;
		case Opt_orlov:
			clear_opt (sbi->s_mount_opt, OLDALLOC);
			break;
#ifdef CONFIG_EXT4DEV_FS_XATTR
		case Opt_user_xattr:
			set_opt (sbi->s_mount_opt, XATTR_USER);
			break;
		case Opt_nouser_xattr:
			clear_opt (sbi->s_mount_opt, XATTR_USER);
			break;
#else
		case Opt_user_xattr:
		case Opt_nouser_xattr:
			printk("EXT4 (no)user_xattr options not supported\n");
			break;
#endif
#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
		case Opt_acl:
			set_opt(sbi->s_mount_opt, POSIX_ACL);
			break;
		case Opt_noacl:
			clear_opt(sbi->s_mount_opt, POSIX_ACL);
			break;
#else
		case Opt_acl:
		case Opt_noacl:
			printk("EXT4 (no)acl options not supported\n");
			break;
#endif
		case Opt_reservation:
			set_opt(sbi->s_mount_opt, RESERVATION);
			break;
		case Opt_noreservation:
			clear_opt(sbi->s_mount_opt, RESERVATION);
			break;
		case Opt_journal_update:
			/* @@@ FIXME */
			/* Eventually we will want to be able to create
			   a journal file here.  For now, only allow the
			   user to specify an existing inode to be the
			   journal file. */
			if (is_remount) {
				printk(KERN_ERR "EXT4-fs: cannot specify "
				       "journal on remount\n");
				return 0;
			}
			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
			break;
		case Opt_journal_inum:
			if (is_remount) {
				printk(KERN_ERR "EXT4-fs: cannot specify "
				       "journal on remount\n");
				return 0;
			}
			if (match_int(&args[0], &option))
				return 0;
			*inum = option;
			break;
		case Opt_journal_dev:
			if (is_remount) {
				printk(KERN_ERR "EXT4-fs: cannot specify "
				       "journal on remount\n");
				return 0;
			}
			if (match_int(&args[0], &option))
				return 0;
			*journal_devnum = option;
			break;
		case Opt_noload:
			set_opt (sbi->s_mount_opt, NOLOAD);
			break;
		case Opt_commit:
			if (match_int(&args[0], &option))
				return 0;
			if (option < 0)
				return 0;
			if (option == 0)
				option = JBD2_DEFAULT_MAX_COMMIT_AGE;
			sbi->s_commit_interval = HZ * option;
			break;
		case Opt_data_journal:
			data_opt = EXT4_MOUNT_JOURNAL_DATA;
			goto datacheck;
		case Opt_data_ordered:
			data_opt = EXT4_MOUNT_ORDERED_DATA;
			goto datacheck;
		case Opt_data_writeback:
			data_opt = EXT4_MOUNT_WRITEBACK_DATA;
		datacheck:
			if (is_remount) {
				if ((sbi->s_mount_opt & EXT4_MOUNT_DATA_FLAGS)
						!= data_opt) {
					printk(KERN_ERR
						"EXT4-fs: cannot change data "
						"mode on remount\n");
					return 0;
				}
			} else {
				sbi->s_mount_opt &= ~EXT4_MOUNT_DATA_FLAGS;
				sbi->s_mount_opt |= data_opt;
			}
			break;
#ifdef CONFIG_QUOTA
		case Opt_usrjquota:
			qtype = USRQUOTA;
			goto set_qf_name;
		case Opt_grpjquota:
			qtype = GRPQUOTA;
set_qf_name:
			if (sb_any_quota_enabled(sb)) {
				printk(KERN_ERR
					"EXT4-fs: Cannot change journalled "
					"quota options when quota turned on.\n");
				return 0;
			}
			qname = match_strdup(&args[0]);
			if (!qname) {
				printk(KERN_ERR
					"EXT4-fs: not enough memory for "
					"storing quotafile name.\n");
				return 0;
			}
			if (sbi->s_qf_names[qtype] &&
			    strcmp(sbi->s_qf_names[qtype], qname)) {
				printk(KERN_ERR
					"EXT4-fs: %s quota file already "
					"specified.\n", QTYPE2NAME(qtype));
				kfree(qname);
				return 0;
			}
			sbi->s_qf_names[qtype] = qname;
			if (strchr(sbi->s_qf_names[qtype], '/')) {
				printk(KERN_ERR
					"EXT4-fs: quotafile must be on "
					"filesystem root.\n");
				kfree(sbi->s_qf_names[qtype]);
				sbi->s_qf_names[qtype] = NULL;
				return 0;
			}
			set_opt(sbi->s_mount_opt, QUOTA);
			break;
		case Opt_offusrjquota:
			qtype = USRQUOTA;
			goto clear_qf_name;
		case Opt_offgrpjquota:
			qtype = GRPQUOTA;
clear_qf_name:
			if (sb_any_quota_enabled(sb)) {
				printk(KERN_ERR "EXT4-fs: Cannot change "
					"journalled quota options when "
					"quota turned on.\n");
				return 0;
			}
			/*
			 * The space will be released later when all options
			 * are confirmed to be correct
			 */
			sbi->s_qf_names[qtype] = NULL;
			break;
		case Opt_jqfmt_vfsold:
			sbi->s_jquota_fmt = QFMT_VFS_OLD;
			break;
		case Opt_jqfmt_vfsv0:
			sbi->s_jquota_fmt = QFMT_VFS_V0;
			break;
		case Opt_quota:
		case Opt_usrquota:
			set_opt(sbi->s_mount_opt, QUOTA);
			set_opt(sbi->s_mount_opt, USRQUOTA);
			break;
		case Opt_grpquota:
			set_opt(sbi->s_mount_opt, QUOTA);
			set_opt(sbi->s_mount_opt, GRPQUOTA);
			break;
		case Opt_noquota:
			if (sb_any_quota_enabled(sb)) {
				printk(KERN_ERR "EXT4-fs: Cannot change quota "
					"options when quota turned on.\n");
				return 0;
			}
			clear_opt(sbi->s_mount_opt, QUOTA);
			clear_opt(sbi->s_mount_opt, USRQUOTA);
			clear_opt(sbi->s_mount_opt, GRPQUOTA);
			break;
#else
		case Opt_quota:
		case Opt_usrquota:
		case Opt_grpquota:
		case Opt_usrjquota:
		case Opt_grpjquota:
		case Opt_offusrjquota:
		case Opt_offgrpjquota:
		case Opt_jqfmt_vfsold:
		case Opt_jqfmt_vfsv0:
			printk(KERN_ERR
				"EXT4-fs: journalled quota options not "
				"supported.\n");
			break;
		case Opt_noquota:
			break;
#endif
		case Opt_abort:
			set_opt(sbi->s_mount_opt, ABORT);
			break;
		case Opt_barrier:
			if (match_int(&args[0], &option))
				return 0;
			if (option)
				set_opt(sbi->s_mount_opt, BARRIER);
			else
				clear_opt(sbi->s_mount_opt, BARRIER);
			break;
		case Opt_ignore:
			break;
		case Opt_resize:
			if (!is_remount) {
				printk("EXT4-fs: resize option only available "
					"for remount\n");
				return 0;
			}
			if (match_int(&args[0], &option) != 0)
				return 0;
			*n_blocks_count = option;
			break;
		case Opt_nobh:
			set_opt(sbi->s_mount_opt, NOBH);
			break;
		case Opt_bh:
			clear_opt(sbi->s_mount_opt, NOBH);
			break;
		case Opt_extents:
			set_opt (sbi->s_mount_opt, EXTENTS);
			break;
		case Opt_noextents:
			clear_opt (sbi->s_mount_opt, EXTENTS);
			break;
		default:
			printk (KERN_ERR
				"EXT4-fs: Unrecognized mount option \"%s\" "
				"or missing value\n", p);
			return 0;
		}
	}
#ifdef CONFIG_QUOTA
	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
		if ((sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA) &&
		     sbi->s_qf_names[USRQUOTA])
			clear_opt(sbi->s_mount_opt, USRQUOTA);

		if ((sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA) &&
		     sbi->s_qf_names[GRPQUOTA])
			clear_opt(sbi->s_mount_opt, GRPQUOTA);

		if ((sbi->s_qf_names[USRQUOTA] &&
				(sbi->s_mount_opt & EXT4_MOUNT_GRPQUOTA)) ||
		    (sbi->s_qf_names[GRPQUOTA] &&
				(sbi->s_mount_opt & EXT4_MOUNT_USRQUOTA))) {
			printk(KERN_ERR "EXT4-fs: old and new quota "
					"format mixing.\n");
			return 0;
		}

		if (!sbi->s_jquota_fmt) {
			printk(KERN_ERR "EXT4-fs: journalled quota format "
					"not specified.\n");
			return 0;
		}
	} else {
		if (sbi->s_jquota_fmt) {
			printk(KERN_ERR "EXT4-fs: journalled quota format "
					"specified with no journalling "
					"enabled.\n");
			return 0;
		}
	}
#endif
	return 1;
}

static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
			    int read_only)
{
	struct ext4_sb_info *sbi = EXT4_SB(sb);
	int res = 0;

	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
		printk (KERN_ERR "EXT4-fs warning: revision level too high, "
			"forcing read-only mode\n");
		res = MS_RDONLY;
	}
	if (read_only)
		return res;
	if (!(sbi->s_mount_state & EXT4_VALID_FS))
		printk (KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
			"running e2fsck is recommended\n");
	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
		printk (KERN_WARNING
			"EXT4-fs warning: mounting fs with errors, "
			"running e2fsck is recommended\n");
	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
		 le16_to_cpu(es->s_mnt_count) >=
		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
		printk (KERN_WARNING
			"EXT4-fs warning: maximal mount count reached, "
			"running e2fsck is recommended\n");
	else if (le32_to_cpu(es->s_checkinterval) &&
		(le32_to_cpu(es->s_lastcheck) +
			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
		printk (KERN_WARNING
			"EXT4-fs warning: checktime reached, "
			"running e2fsck is recommended\n");
#if 0
		/* @@@ We _will_ want to clear the valid bit if we find
		 * inconsistencies, to force a fsck at reboot.  But for
		 * a plain journaled filesystem we can keep it set as
		 * valid forever! :)
		 */
	es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT4_VALID_FS);
#endif
	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
		es->s_max_mnt_count = cpu_to_le16(EXT4_DFL_MAX_MNT_COUNT);
	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
	es->s_mtime = cpu_to_le32(get_seconds());
	ext4_update_dynamic_rev(sb);
	EXT4_SET_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);

	ext4_commit_super(sb, es, 1);
	if (test_opt(sb, DEBUG))
		printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%lu, "
				"bpg=%lu, ipg=%lu, mo=%04lx]\n",
			sb->s_blocksize,
			sbi->s_groups_count,
			EXT4_BLOCKS_PER_GROUP(sb),
			EXT4_INODES_PER_GROUP(sb),
			sbi->s_mount_opt);

	printk(KERN_INFO "EXT4 FS on %s, ", sb->s_id);
	if (EXT4_SB(sb)->s_journal->j_inode == NULL) {
		char b[BDEVNAME_SIZE];

		printk("external journal on %s\n",
			bdevname(EXT4_SB(sb)->s_journal->j_dev, b));
	} else {
		printk("internal journal\n");
	}
	return res;
}

__le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
			    struct ext4_group_desc *gdp)
{
	__u16 crc = 0;

	if (sbi->s_es->s_feature_ro_compat &
	    cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
		int offset = offsetof(struct ext4_group_desc, bg_checksum);
		__le32 le_group = cpu_to_le32(block_group);

		crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid));
		crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group));
		crc = crc16(crc, (__u8 *)gdp, offset);
		offset += sizeof(gdp->bg_checksum); /* skip checksum */
		/* for checksum of struct ext4_group_desc do the rest...*/
		if ((sbi->s_es->s_feature_incompat &
		     cpu_to_le32(EXT4_FEATURE_INCOMPAT_64BIT)) &&
		    offset < le16_to_cpu(sbi->s_es->s_desc_size))
			crc = crc16(crc, (__u8 *)gdp + offset,
				    le16_to_cpu(sbi->s_es->s_desc_size) -
					offset);
	}

	return cpu_to_le16(crc);
}

int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
				struct ext4_group_desc *gdp)
{
	if ((sbi->s_es->s_feature_ro_compat &
	     cpu_to_le32(EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) &&
	    (gdp->bg_checksum != ext4_group_desc_csum(sbi, block_group, gdp)))
		return 0;

	return 1;
}