mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-24 07:30:54 +07:00
561a75acda
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.
Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.
Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Link: https://lore.kernel.org/r/20200708062842.12214-1-grandmaster@al2klimov.de
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
113 lines
4.1 KiB
ReStructuredText
113 lines
4.1 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
================================
|
|
Optimized MPEG Filesystem (OMFS)
|
|
================================
|
|
|
|
Overview
|
|
========
|
|
|
|
OMFS is a filesystem created by SonicBlue for use in the ReplayTV DVR
|
|
and Rio Karma MP3 player. The filesystem is extent-based, utilizing
|
|
block sizes from 2k to 8k, with hash-based directories. This
|
|
filesystem driver may be used to read and write disks from these
|
|
devices.
|
|
|
|
Note, it is not recommended that this FS be used in place of a general
|
|
filesystem for your own streaming media device. Native Linux filesystems
|
|
will likely perform better.
|
|
|
|
More information is available at:
|
|
|
|
http://linux-karma.sf.net/
|
|
|
|
Various utilities, including mkomfs and omfsck, are included with
|
|
omfsprogs, available at:
|
|
|
|
https://bobcopeland.com/karma/
|
|
|
|
Instructions are included in its README.
|
|
|
|
Options
|
|
=======
|
|
|
|
OMFS supports the following mount-time options:
|
|
|
|
============ ========================================
|
|
uid=n make all files owned by specified user
|
|
gid=n make all files owned by specified group
|
|
umask=xxx set permission umask to xxx
|
|
fmask=xxx set umask to xxx for files
|
|
dmask=xxx set umask to xxx for directories
|
|
============ ========================================
|
|
|
|
Disk format
|
|
===========
|
|
|
|
OMFS discriminates between "sysblocks" and normal data blocks. The sysblock
|
|
group consists of super block information, file metadata, directory structures,
|
|
and extents. Each sysblock has a header containing CRCs of the entire
|
|
sysblock, and may be mirrored in successive blocks on the disk. A sysblock may
|
|
have a smaller size than a data block, but since they are both addressed by the
|
|
same 64-bit block number, any remaining space in the smaller sysblock is
|
|
unused.
|
|
|
|
Sysblock header information::
|
|
|
|
struct omfs_header {
|
|
__be64 h_self; /* FS block where this is located */
|
|
__be32 h_body_size; /* size of useful data after header */
|
|
__be16 h_crc; /* crc-ccitt of body_size bytes */
|
|
char h_fill1[2];
|
|
u8 h_version; /* version, always 1 */
|
|
char h_type; /* OMFS_INODE_X */
|
|
u8 h_magic; /* OMFS_IMAGIC */
|
|
u8 h_check_xor; /* XOR of header bytes before this */
|
|
__be32 h_fill2;
|
|
};
|
|
|
|
Files and directories are both represented by omfs_inode::
|
|
|
|
struct omfs_inode {
|
|
struct omfs_header i_head; /* header */
|
|
__be64 i_parent; /* parent containing this inode */
|
|
__be64 i_sibling; /* next inode in hash bucket */
|
|
__be64 i_ctime; /* ctime, in milliseconds */
|
|
char i_fill1[35];
|
|
char i_type; /* OMFS_[DIR,FILE] */
|
|
__be32 i_fill2;
|
|
char i_fill3[64];
|
|
char i_name[OMFS_NAMELEN]; /* filename */
|
|
__be64 i_size; /* size of file, in bytes */
|
|
};
|
|
|
|
Directories in OMFS are implemented as a large hash table. Filenames are
|
|
hashed then prepended into the bucket list beginning at OMFS_DIR_START.
|
|
Lookup requires hashing the filename, then seeking across i_sibling pointers
|
|
until a match is found on i_name. Empty buckets are represented by block
|
|
pointers with all-1s (~0).
|
|
|
|
A file is an omfs_inode structure followed by an extent table beginning at
|
|
OMFS_EXTENT_START::
|
|
|
|
struct omfs_extent_entry {
|
|
__be64 e_cluster; /* start location of a set of blocks */
|
|
__be64 e_blocks; /* number of blocks after e_cluster */
|
|
};
|
|
|
|
struct omfs_extent {
|
|
__be64 e_next; /* next extent table location */
|
|
__be32 e_extent_count; /* total # extents in this table */
|
|
__be32 e_fill;
|
|
struct omfs_extent_entry e_entry; /* start of extent entries */
|
|
};
|
|
|
|
Each extent holds the block offset followed by number of blocks allocated to
|
|
the extent. The final extent in each table is a terminator with e_cluster
|
|
being ~0 and e_blocks being ones'-complement of the total number of blocks
|
|
in the table.
|
|
|
|
If this table overflows, a continuation inode is written and pointed to by
|
|
e_next. These have a header but lack the rest of the inode structure.
|
|
|