ext4: Add mount options in superblock

Allow mount options to be stored in the superblock.  Also add default
mount option bits for nobarrier, block_validity, discard, and nodelalloc.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

2 files changed, 30 insertions, 8 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9ca3637eca5f..ed14e1db0832 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1025,8 +1025,9 @@ struct ext4_super_block {
         __le32  s_last_error_line;      /* line number where error happened */
         __le64  s_last_error_block;     /* block involved of last error */
         __u8    s_last_error_func[32];  /* function where the error happened */
-#define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_reserved)
-        __le32   s_reserved[128];        /* Padding to the end of the block */
+#define EXT4_S_ERR_END offsetof(struct ext4_super_block, s_mount_opts)
+        __u8    s_mount_opts[64];
+        __le32  s_reserved[112];        /* Padding to the end of the block */
 };
 
 #define EXT4_S_ERR_LEN (EXT4_S_ERR_END - EXT4_S_ERR_START)
@@ -1341,6 +1342,10 @@ EXT4_INODE_BIT_FNS(state, state_flags)
 #define EXT4_DEFM_JMODE_DATA    0x0020
 #define EXT4_DEFM_JMODE_ORDERED 0x0040
 #define EXT4_DEFM_JMODE_WBACK   0x0060
+#define EXT4_DEFM_NOBARRIER     0x0100
+#define EXT4_DEFM_BLOCK_VALIDITY 0x0200
+#define EXT4_DEFM_DISCARD       0x0400
+#define EXT4_DEFM_NODELALLOC    0x0800
 
 /*
  * Default journal batch times
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3e3f6484c223..3fd65eb66ccd 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1003,10 +1003,10 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",journal_checksum");
         if (test_opt(sb, I_VERSION))
                 seq_puts(seq, ",i_version");
-        if (!test_opt(sb, DELALLOC))
+        if (!test_opt(sb, DELALLOC) &&
+            !(def_mount_opts & EXT4_DEFM_NODELALLOC))
                 seq_puts(seq, ",nodelalloc");
 
-
         if (sbi->s_stripe)
                 seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
         /*
@@ -1030,7 +1030,7 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
         if (test_opt(sb, NO_AUTO_DA_ALLOC))
                 seq_puts(seq, ",noauto_da_alloc");
 
-        if (test_opt(sb, DISCARD))
+        if (test_opt(sb, DISCARD) && !(def_mount_opts & EXT4_DEFM_DISCARD))
                 seq_puts(seq, ",discard");
 
         if (test_opt(sb, NOLOAD))
@@ -1039,6 +1039,10 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
         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");
+
         ext4_show_quota_options(seq, sb);
 
         return 0;
@@ -2655,6 +2659,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
         else
                 set_opt(sbi->s_mount_opt, ERRORS_RO);
+        if (def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY)
+                set_opt(sbi->s_mount_opt, BLOCK_VALIDITY);
+        if (def_mount_opts & EXT4_DEFM_DISCARD)
+                set_opt(sbi->s_mount_opt, DISCARD);
 
         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
@@ -2662,15 +2670,23 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
         sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME;
         sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME;
 
-        set_opt(sbi->s_mount_opt, BARRIER);
+        if ((def_mount_opts & EXT4_DEFM_NOBARRIER) == 0)
+                set_opt(sbi->s_mount_opt, BARRIER);
 
         /*
          * enable delayed allocation by default
          * Use -o nodelalloc to turn it off
          */
-        if (!IS_EXT3_SB(sb))
+        if (!IS_EXT3_SB(sb) &&
+            ((def_mount_opts & EXT4_DEFM_NODELALLOC) == 0))
                 set_opt(sbi->s_mount_opt, DELALLOC);
 
+        if (!parse_options((char *) sbi->s_es->s_mount_opts, sb,
+                           &journal_devnum, &journal_ioprio, NULL, 0)) {
+                ext4_msg(sb, KERN_WARNING,
+                         "failed to parse options in superblock: %s",
+                         sbi->s_es->s_mount_opts);
+        }
         if (!parse_options((char *) data, sb, &journal_devnum,
                            &journal_ioprio, NULL, 0))
                 goto failed_mount;
@@ -3141,7 +3157,8 @@ no_journal:
                 descr = "out journal";
 
         ext4_msg(sb, KERN_INFO, "mounted filesystem with%s. "
-                "Opts: %s", descr, orig_data);
+                 "Opts: %s%s%s", descr, sbi->s_es->s_mount_opts,
+                 *sbi->s_es->s_mount_opts ? "; " : "", orig_data);
 
         init_timer(&sbi->s_err_report);
         sbi->s_err_report.function = print_daily_error_info;