ext4: make ext4_show_options() be table-driven

Consistently show mount options which are the non-default, so that
/proc/mounts accurately shows the mount options that would be
necessary to mount the file system in its current mode of operation.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -1143,6 +1143,7 @@ struct ext4_sb_info {
 	unsigned int s_mount_opt;
 	unsigned int s_mount_opt2;
 	unsigned int s_mount_flags;
+	unsigned int s_def_mount_opt;
 	ext4_fsblk_t s_sb_block;
 	uid_t s_resuid;
 	gid_t s_resgid;

fs/ext4/super.c

@@ -1198,8 +1198,8 @@ static const match_table_t tokens = {
 	{Opt_nouser_xattr, "nouser_xattr"},
 	{Opt_acl, "acl"},
 	{Opt_noacl, "noacl"},
-	{Opt_noload, "noload"},
 	{Opt_noload, "norecovery"},
+	{Opt_noload, "noload"},
 	{Opt_removed, "nobh"},
 	{Opt_removed, "bh"},
 	{Opt_commit, "commit=%u"},
@@ -1668,6 +1668,16 @@ static inline void ext4_show_quota_options(struct seq_file *seq,
 #endif
 }
 
+static const char *token2str(int token)
+{
+	static const struct match_token *t;
+
+	for (t = tokens; t->token != Opt_err; t++)
+		if (t->token == token && !strchr(t->pattern, '='))
+			break;
+	return t->pattern;
+}
+
 /*
  * Show an option if
  *  - it's set to a non-default value OR
@@ -1676,132 +1686,71 @@ static inline void ext4_show_quota_options(struct seq_file *seq,
 static int ext4_show_options(struct seq_file *seq, struct dentry *root)
 {
 	int def_errors;
-	unsigned long def_mount_opts;
 	struct super_block *sb = root->d_sb;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_super_block *es = sbi->s_es;
+	const struct mount_opts *m;
 
-	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
-	def_errors     = le16_to_cpu(es->s_errors);
+#define SEQ_OPTS_PUTS(str) seq_printf(seq, "," str)
+#define SEQ_OPTS_PRINT(str, arg) seq_printf(seq, "," str, arg)
 
 	if (sbi->s_sb_block != 1)
-		seq_printf(seq, ",sb=%llu", sbi->s_sb_block);
-	if (test_opt(sb, MINIX_DF))
-		seq_puts(seq, ",minixdf");
-	if (test_opt(sb, GRPID) && !(def_mount_opts & EXT4_DEFM_BSDGROUPS))
-		seq_puts(seq, ",grpid");
-	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT4_DEFM_BSDGROUPS))
-		seq_puts(seq, ",nogrpid");
-	if (sbi->s_resuid != EXT4_DEF_RESUID ||
-	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID) {
-		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
+		SEQ_OPTS_PRINT("sb=%llu", sbi->s_sb_block);
+
+	for (m = ext4_mount_opts; m->token != Opt_err; m++) {
+		int want_set = m->flags & MOPT_SET;
+		if (((m->flags & (MOPT_SET|MOPT_CLEAR)) == 0) ||
+		    (m->flags & MOPT_CLEAR_ERR))
+			continue;
+		if (!(m->mount_opt & (sbi->s_mount_opt ^ sbi->s_def_mount_opt)))
+			continue; /* skip if same as the default */
+		if ((want_set &&
+		     (sbi->s_mount_opt & m->mount_opt) != m->mount_opt) ||
+		    (!want_set && (sbi->s_mount_opt & m->mount_opt)))
+			continue; /* select Opt_noFoo vs Opt_Foo */
+		SEQ_OPTS_PRINT("%s", token2str(m->token));
 	}
+
+	if (sbi->s_resuid != EXT4_DEF_RESUID ||
+	    le16_to_cpu(es->s_def_resuid) != EXT4_DEF_RESUID)
+		SEQ_OPTS_PRINT("resuid=%u", sbi->s_resuid);
 	if (sbi->s_resgid != EXT4_DEF_RESGID ||
-	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID) {
-		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
-	}
-	if (test_opt(sb, ERRORS_RO)) {
-		if (def_errors == EXT4_ERRORS_PANIC ||
-		    def_errors == EXT4_ERRORS_CONTINUE) {
-			seq_puts(seq, ",errors=remount-ro");
-		}
-	}
+	    le16_to_cpu(es->s_def_resgid) != EXT4_DEF_RESGID)
+		SEQ_OPTS_PRINT("resgid=%u", sbi->s_resgid);
+	def_errors = le16_to_cpu(es->s_errors);
+	if (test_opt(sb, ERRORS_RO) && def_errors != EXT4_ERRORS_RO)
+		SEQ_OPTS_PUTS("errors=remount-ro");
 	if (test_opt(sb, ERRORS_CONT) && def_errors != EXT4_ERRORS_CONTINUE)
-		seq_puts(seq, ",errors=continue");
+		SEQ_OPTS_PUTS("errors=continue");
 	if (test_opt(sb, ERRORS_PANIC) && def_errors != EXT4_ERRORS_PANIC)
-		seq_puts(seq, ",errors=panic");
-	if (test_opt(sb, NO_UID32) && !(def_mount_opts & EXT4_DEFM_UID16))
-		seq_puts(seq, ",nouid32");
-	if (test_opt(sb, DEBUG) && !(def_mount_opts & EXT4_DEFM_DEBUG))
-		seq_puts(seq, ",debug");
-#ifdef CONFIG_EXT4_FS_XATTR
-	if (test_opt(sb, XATTR_USER))
-		seq_puts(seq, ",user_xattr");
-	if (!test_opt(sb, XATTR_USER))
-		seq_puts(seq, ",nouser_xattr");
-#endif
-#ifdef CONFIG_EXT4_FS_POSIX_ACL
-	if (test_opt(sb, POSIX_ACL) && !(def_mount_opts & EXT4_DEFM_ACL))
-		seq_puts(seq, ",acl");
-	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT4_DEFM_ACL))
-		seq_puts(seq, ",noacl");
-#endif
-	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ) {
-		seq_printf(seq, ",commit=%u",
-			   (unsigned) (sbi->s_commit_interval / HZ));
-	}
-	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME) {
-		seq_printf(seq, ",min_batch_time=%u",
-			   (unsigned) sbi->s_min_batch_time);
-	}
-	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME) {
-		seq_printf(seq, ",max_batch_time=%u",
-			   (unsigned) sbi->s_max_batch_time);
-	}
-
-	/*
-	 * We're changing the default of barrier mount option, so
-	 * let's always display its mount state so it's clear what its
-	 * status is.
-	 */
-	seq_puts(seq, ",barrier=");
-	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
-	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
-		seq_puts(seq, ",journal_async_commit");
-	else if (test_opt(sb, JOURNAL_CHECKSUM))
-		seq_puts(seq, ",journal_checksum");
+		SEQ_OPTS_PUTS("errors=panic");
+	if (sbi->s_commit_interval != JBD2_DEFAULT_MAX_COMMIT_AGE*HZ)
+		SEQ_OPTS_PRINT("commit=%lu", sbi->s_commit_interval / HZ);
+	if (sbi->s_min_batch_time != EXT4_DEF_MIN_BATCH_TIME)
+		SEQ_OPTS_PRINT("min_batch_time=%u", sbi->s_min_batch_time);
+	if (sbi->s_max_batch_time != EXT4_DEF_MAX_BATCH_TIME)
+		SEQ_OPTS_PRINT("max_batch_time=%u", sbi->s_max_batch_time);
 	if (sb->s_flags & MS_I_VERSION)
-		seq_puts(seq, ",i_version");
-	if (!test_opt(sb, DELALLOC) &&
-	    !(def_mount_opts & EXT4_DEFM_NODELALLOC))
-		seq_puts(seq, ",nodelalloc");
-
-	if (!test_opt(sb, MBLK_IO_SUBMIT))
-		seq_puts(seq, ",nomblk_io_submit");
+		SEQ_OPTS_PUTS("i_version");
 	if (sbi->s_stripe)
-		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
-	/*
-	 * journal mode get enabled in different ways
-	 * So just print the value even if we didn't specify it
-	 */
+		SEQ_OPTS_PRINT("stripe=%lu", sbi->s_stripe);
+	if (EXT4_MOUNT_DATA_FLAGS & (sbi->s_mount_opt ^ sbi->s_def_mount_opt)) {
 		if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA)
-		seq_puts(seq, ",data=journal");
+			SEQ_OPTS_PUTS("data=journal");
 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA)
-		seq_puts(seq, ",data=ordered");
+			SEQ_OPTS_PUTS("data=ordered");
 		else if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA)
-		seq_puts(seq, ",data=writeback");
-
+			SEQ_OPTS_PUTS("data=writeback");
+	}
 	if (sbi->s_inode_readahead_blks != EXT4_DEF_INODE_READAHEAD_BLKS)
-		seq_printf(seq, ",inode_readahead_blks=%u",
+		SEQ_OPTS_PRINT("inode_readahead_blks=%u",
 			       sbi->s_inode_readahead_blks);
 
-	if (test_opt(sb, DATA_ERR_ABORT))
-		seq_puts(seq, ",data_err=abort");
-
-	if (test_opt(sb, NO_AUTO_DA_ALLOC))
-		seq_puts(seq, ",noauto_da_alloc");
-
-	if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
-		seq_puts(seq, ",discard");
-
-	if (test_opt(sb, NOLOAD))
-		seq_puts(seq, ",norecovery");
-
-	if (test_opt(sb, DIOREAD_NOLOCK))
-		seq_puts(seq, ",dioread_nolock");
-
-	if (test_opt(sb, BLOCK_VALIDITY) &&
-	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
-		seq_puts(seq, ",block_validity");
-
-	if (!test_opt(sb, INIT_INODE_TABLE))
-		seq_puts(seq, ",noinit_itable");
-	else if (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT)
-		seq_printf(seq, ",init_itable=%u",
-			   (unsigned) sbi->s_li_wait_mult);
+	if (test_opt(sb, INIT_INODE_TABLE) &&
+	    (sbi->s_li_wait_mult != EXT4_DEF_LI_WAIT_MULT))
+		SEQ_OPTS_PRINT("init_itable=%u", sbi->s_li_wait_mult);
 
 	ext4_show_quota_options(seq, sb);
-
 	return 0;
 }
 
@@ -3105,6 +3054,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 			 "failed to parse options in superblock: %s",
 			 sbi->s_es->s_mount_opts);
 	}
+	sbi->s_def_mount_opt = sbi->s_mount_opt;
 	if (!parse_options((char *) data, sb, &journal_devnum,
 			   &journal_ioprio, 0))
 		goto failed_mount;