journal-superblock-changes

   1 ext4: journal superblock changes
   2
   3 There are a number of changes to the ext4 superblock during the mount
   4 process which are done without using the journal, but instead via the
   5 brute-force call to ext4_commit_super().  Concentrate these changes to
   6 ext4_setup_super(), and make them using the journalling mechanism.
   7
   8 Not only is this more efficient, but it also avoids some cases where
   9 the ext4 superblock's checksum was not properly set.
  10
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/ext4/super.c | 47 +++++++++++++++++++++++++++--------------------
  14  1 file changed, 27 insertions(+), 20 deletions(-)
  15
  16 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  17 index a673558fe5f8..67cb11f15aba 100644
  18 --- a/fs/ext4/super.c
  19 +++ b/fs/ext4/super.c
  20 @@ -2064,9 +2064,10 @@ int ext4_seq_options_show(struct seq_file *seq, void *offset)
  21  }
  22
  23  static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  24 -                           int read_only)
  25 +                           unsigned long journal_devnum, int read_only)
  26  {
  27         struct ext4_sb_info *sbi = EXT4_SB(sb);
  28 +       handle_t *handle;
  29         int res = 0;
  30
  31         if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
  32 @@ -2074,7 +2075,7 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  33                          "forcing read-only mode");
  34                 res = MS_RDONLY;
  35         }
  36 -       if (read_only)
  37 +       if (read_only || res)
  38                 goto done;
  39         if (!(sbi->s_mount_state & EXT4_VALID_FS))
  40                 ext4_msg(sb, KERN_WARNING, "warning: mounting unchecked fs, "
  41 @@ -2095,6 +2096,15 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  42                 ext4_msg(sb, KERN_WARNING,
  43                          "warning: checktime reached, "
  44                          "running e2fsck is recommended");
  45 +       handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
  46 +       if (IS_ERR(handle))
  47 +               return PTR_ERR(handle);
  48 +       res = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh);
  49 +       if (res) {
  50 +       stop_journal:
  51 +               ext4_journal_stop(handle);
  52 +               return res;
  53 +       }
  54         if (!sbi->s_journal)
  55                 es->s_state &= cpu_to_le16(~EXT4_VALID_FS);
  56         if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
  57 @@ -2104,7 +2114,16 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
  58         ext4_update_dynamic_rev(sb);
  59         if (sbi->s_journal)
  60                 ext4_set_feature_journal_needs_recovery(sb);
  61 -
  62 +       if (journal_devnum)
  63 +               es->s_journal_dev = cpu_to_le32(journal_devnum);
  64 +       if (DUMMY_ENCRYPTION_ENABLED(sbi))
  65 +               ext4_set_feature_encrypt(sb);
  66 +       res = ext4_handle_dirty_super(handle, sb);
  67 +       if (res)
  68 +               goto stop_journal;
  69 +       res = ext4_journal_stop(handle);
  70 +       if (res)
  71 +               return res;
  72         ext4_commit_super(sb, 1);
  73  done:
  74         if (test_opt(sb, DEBUG))
  75 @@ -4048,12 +4067,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  76                 goto failed_mount_wq;
  77         }
  78
  79 -       if (DUMMY_ENCRYPTION_ENABLED(sbi) && !(sb->s_flags & MS_RDONLY) &&
  80 -           !ext4_has_feature_encrypt(sb)) {
  81 -               ext4_set_feature_encrypt(sb);
  82 -               ext4_commit_super(sb, 1);
  83 -       }
  84 -
  85         /*
  86          * Get the # of file system overhead blocks from the
  87          * superblock if present.
  88 @@ -4102,7 +4115,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  89                 goto failed_mount4;
  90         }
  91
  92 -       if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
  93 +       err = ext4_setup_super(sb, es, journal_devnum, sb->s_flags & MS_RDONLY);
  94 +       if (err < 0)
  95 +               goto failed_mount4a;
  96 +       if (err)
  97                 sb->s_flags |= MS_RDONLY;
  98
  99         /* determine the minimum size of new large inodes, if present */
 100 @@ -4561,15 +4577,6 @@ static int ext4_load_journal(struct super_block *sb,
 101
 102         EXT4_SB(sb)->s_journal = journal;
 103         ext4_clear_journal_err(sb, es);
 104 -
 105 -       if (!really_read_only && journal_devnum &&
 106 -           journal_devnum != le32_to_cpu(es->s_journal_dev)) {
 107 -               es->s_journal_dev = cpu_to_le32(journal_devnum);
 108 -
 109 -               /* Make sure we flush the recovery flag to disk. */
 110 -               ext4_commit_super(sb, 1);
 111 -       }
 112 -
 113         return 0;
 114  }
 115
 116 @@ -5032,7 +5039,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 117                         if (sbi->s_journal)
 118                                 ext4_clear_journal_err(sb, es);
 119                         sbi->s_mount_state = le16_to_cpu(es->s_state);
 120 -                       if (!ext4_setup_super(sb, es, 0))
 121 +                       if (!ext4_setup_super(sb, es, 0, 0))
 122                                 sb->s_flags &= ~MS_RDONLY;
 123                         if (ext4_has_feature_mmp(sb))
 124                                 if (ext4_multi_mount_protect(sb,