ext4: documentation fixes

This commit aims to fix the following issues in ext4 documentation:
- Flexible block group docs said that the aim was to group block
  metadata together instead of block group metadata.
- The documentation consistly uses "location" instead of "block number".
  It is easy to confuse location to be an absolute offset on disk. Added
  a line to clarify all location values are in terms of block numbers.
- Dirent2 docs said that the rec_len field is shortened instead of the
  name_len field.
- Typo in bg_checksum description.
- Inode size is 160 bytes now, and hence i_extra_isize is now 32.
- Cluster size formula was incorrect, it did not include the +10 to
  s_log_cluster_size value.
- Typo: there were two s_wtime_hi in the superblock struct.
- Superblock struct was outdated, added the new fields which were part
  of s_reserved earlier.
- Multiple mount protection seems to be implemented in fs/ext4/mmp.c.

Signed-off-by: Ayush Ranjan <ayushr2@illinois.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>

1 files changed, 1 insertions, 1 deletions

diff --git a/Documentation/filesystems/ext4/directory.rst b/Documentation/filesystems/ext4/directory.rst
index 614034e24669..073940cc64ed 100644
--- a/Documentation/filesystems/ext4/directory.rst
+++ b/Documentation/filesystems/ext4/directory.rst
@@ -59,7 +59,7 @@ is at most 263 bytes long, though on disk you'll need to reference
      - File name.
 
 Since file names cannot be longer than 255 bytes, the new directory
-entry format shortens the rec\_len field and uses the space for a file
+entry format shortens the name\_len field and uses the space for a file
 type flag, probably to avoid having to load every inode during directory
 tree traversal. This format is ``ext4_dir_entry_2``, which is at most
 263 bytes long, though on disk you'll need to reference