create-nojournal_checksum-mount-option

   1 ext4: create nojournal_checksum mount option
   2
   3 From: "Darrick J. Wong" <darrick.wong@oracle.com>
   4
   5 Create a mount option to disable journal checksumming (because the
   6 metadata_csum feature turns it on by default now), and fix remount not
   7 to allow changing the journal checksumming option, since changing the
   8 mount options has no effect on the journal.
   9
  10 Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
  11 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  12 ---
  13  fs/ext4/super.c |   13 ++++++++++++-
  14  1 file changed, 12 insertions(+), 1 deletion(-)
  15
  16
  17 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
  18 index 5d51dbf..bf46927 100644
  19 --- a/fs/ext4/super.c
  20 +++ b/fs/ext4/super.c
  21 @@ -1166,7 +1166,7 @@ enum {
  22         Opt_inode_readahead_blks, Opt_journal_ioprio,
  23         Opt_dioread_nolock, Opt_dioread_lock,
  24         Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
  25 -       Opt_max_dir_size_kb,
  26 +       Opt_max_dir_size_kb, Opt_nojournal_checksum,
  27  };
  28
  29  static const match_table_t tokens = {
  30 @@ -1200,6 +1200,7 @@ static const match_table_t tokens = {
  31         {Opt_journal_dev, "journal_dev=%u"},
  32         {Opt_journal_path, "journal_path=%s"},
  33         {Opt_journal_checksum, "journal_checksum"},
  34 +       {Opt_nojournal_checksum, "nojournal_checksum"},
  35         {Opt_journal_async_commit, "journal_async_commit"},
  36         {Opt_abort, "abort"},
  37         {Opt_data_journal, "data=journal"},
  38 @@ -1381,6 +1382,8 @@ static const struct mount_opts {
  39          MOPT_EXT4_ONLY | MOPT_SET | MOPT_EXPLICIT},
  40         {Opt_nodelalloc, EXT4_MOUNT_DELALLOC,
  41          MOPT_EXT4_ONLY | MOPT_CLEAR},
  42 +       {Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
  43 +        MOPT_EXT4_ONLY | MOPT_CLEAR},
  44         {Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
  45          MOPT_EXT4_ONLY | MOPT_SET},
  46         {Opt_journal_async_commit, (EXT4_MOUNT_JOURNAL_ASYNC_COMMIT |
  47 @@ -4837,6 +4840,14 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
  48                 goto restore_opts;
  49         }
  50
  51 +       if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
  52 +           test_opt(sb, JOURNAL_CHECKSUM)) {
  53 +               ext4_msg(sb, KERN_ERR, "changing journal_checksum "
  54 +                        "during remount not supported");
  55 +               err = -EINVAL;
  56 +               goto restore_opts;
  57 +       }
  58 +
  59         if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
  60                 if (test_opt2(sb, EXPLICIT_DELALLOC)) {
  61                         ext4_msg(sb, KERN_ERR, "can't mount with "
  62
  63