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 | 50 +++++++++++++++++++++++++++++---------------------
  14  1 file changed, 29 insertions(+), 21 deletions(-)
  15
  16 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  17 index a673558fe5f8..14360a1aae81 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 @@ -2104,8 +2114,18 @@ 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 -       ext4_commit_super(sb, 1);
  63 +       if (journal_devnum)
  64 +               es->s_journal_dev = cpu_to_le32(journal_devnum);
  65 +       if (DUMMY_ENCRYPTION_ENABLED(sbi))
  66 +               ext4_set_feature_encrypt(sb);
  67 +       res = ext4_handle_dirty_super(handle, sb);
  68 +       if (res)
  69 +               goto stop_journal;
  70 +       res = ext4_journal_stop(handle);
  71 +       if (res)
  72 +               return res;
  73 +       if (!sbi->s_journal)
  74 +               ext4_commit_super(sb, 1);
  75  done:
  76         if (test_opt(sb, DEBUG))
  77                 printk(KERN_INFO "[EXT4 FS bs=%lu, gc=%u, "
  78 @@ -4048,12 +4068,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  79                 goto failed_mount_wq;
  80         }
  81
  82 -       if (DUMMY_ENCRYPTION_ENABLED(sbi) && !(sb->s_flags & MS_RDONLY) &&
  83 -           !ext4_has_feature_encrypt(sb)) {
  84 -               ext4_set_feature_encrypt(sb);
  85 -               ext4_commit_super(sb, 1);
  86 -       }
  87 -
  88         /*
  89          * Get the # of file system overhead blocks from the
  90          * superblock if present.
  91 @@ -4102,7 +4116,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
  92                 goto failed_mount4;
  93         }
  94
  95 -       if (ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY))
  96 +       err = ext4_setup_super(sb, es, journal_devnum, sb->s_flags & MS_RDONLY);
  97 +       if (err < 0)
  98 +               goto failed_mount4a;
  99 +       if (err)
 100                 sb->s_flags |= MS_RDONLY;
 101
 102         /* determine the minimum size of new large inodes, if present */
 103 @@ -4561,15 +4578,6 @@ static int ext4_load_journal(struct super_block *sb,
 104
 105         EXT4_SB(sb)->s_journal = journal;
 106         ext4_clear_journal_err(sb, es);
 107 -
 108 -       if (!really_read_only && journal_devnum &&
 109 -           journal_devnum != le32_to_cpu(es->s_journal_dev)) {
 110 -               es->s_journal_dev = cpu_to_le32(journal_devnum);
 111 -
 112 -               /* Make sure we flush the recovery flag to disk. */
 113 -               ext4_commit_super(sb, 1);
 114 -       }
 115 -
 116         return 0;
 117  }
 118
 119 @@ -5032,7 +5040,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 120                         if (sbi->s_journal)
 121                                 ext4_clear_journal_err(sb, es);
 122                         sbi->s_mount_state = le16_to_cpu(es->s_state);
 123 -                       if (!ext4_setup_super(sb, es, 0))
 124 +                       if (!ext4_setup_super(sb, es, 0, 0))
 125                                 sb->s_flags &= ~MS_RDONLY;
 126                         if (ext4_has_feature_mmp(sb))
 127                                 if (ext4_multi_mount_protect(sb,