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| author | Ayush Ranjan <ayushr2@illinois.edu> | 2019-08-22 23:18:33 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-08-22 23:18:33 -0400 |
| commit | 219db95bbe796277c739cca17fe134f6c2ce6676 (patch) | |
| tree | ac53215637ce5b611c1f5233558c382f05fded13 /Documentation/filesystems/ext4/group_descr.rst | |
| parent | 7963e5ac901251c7a3b36fe7c987623a3f309393 (diff) | |
| download | lwn-219db95bbe796277c739cca17fe134f6c2ce6676.tar.gz lwn-219db95bbe796277c739cca17fe134f6c2ce6676.zip | |
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- Superblock struct was outdated, added the new fields which were part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>
Diffstat (limited to 'Documentation/filesystems/ext4/group_descr.rst')
| -rw-r--r-- | Documentation/filesystems/ext4/group_descr.rst | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/Documentation/filesystems/ext4/group_descr.rst b/Documentation/filesystems/ext4/group_descr.rst index 0f783ed88592..7ba6114e7f5c 100644 --- a/Documentation/filesystems/ext4/group_descr.rst +++ b/Documentation/filesystems/ext4/group_descr.rst @@ -99,9 +99,12 @@ The block group descriptor is laid out in ``struct ext4_group_desc``. * - 0x1E - \_\_le16 - bg\_checksum - - Group descriptor checksum; crc16(sb\_uuid+group+desc) if the - RO\_COMPAT\_GDT\_CSUM feature is set, or crc32c(sb\_uuid+group\_desc) & - 0xFFFF if the RO\_COMPAT\_METADATA\_CSUM feature is set. + - Group descriptor checksum; crc16(sb\_uuid+group\_num+bg\_desc) if the + RO\_COMPAT\_GDT\_CSUM feature is set, or + crc32c(sb\_uuid+group\_num+bg\_desc) & 0xFFFF if the + RO\_COMPAT\_METADATA\_CSUM feature is set. The bg\_checksum + field in bg\_desc is skipped when calculating crc16 checksum, + and set to zero if crc32c checksum is used. * - - - |