From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- Documentation/filesystems/sysv-fs.rst | 264 ++++++++++++++++++++++++++++++++++ 1 file changed, 264 insertions(+) create mode 100644 Documentation/filesystems/sysv-fs.rst (limited to 'Documentation/filesystems/sysv-fs.rst') diff --git a/Documentation/filesystems/sysv-fs.rst b/Documentation/filesystems/sysv-fs.rst new file mode 100644 index 000000000..89e40911a --- /dev/null +++ b/Documentation/filesystems/sysv-fs.rst @@ -0,0 +1,264 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================== +SystemV Filesystem +================== + +It implements all of + - Xenix FS, + - SystemV/386 FS, + - Coherent FS. + +To install: + +* Answer the 'System V and Coherent filesystem support' question with 'y' + when configuring the kernel. +* To mount a disk or a partition, use:: + + mount [-r] -t sysv device mountpoint + + The file system type names:: + + -t sysv + -t xenix + -t coherent + + may be used interchangeably, but the last two will eventually disappear. + +Bugs in the present implementation: + +- Coherent FS: + + - The "free list interleave" n:m is currently ignored. + - Only file systems with no filesystem name and no pack name are recognized. + (See Coherent "man mkfs" for a description of these features.) + +- SystemV Release 2 FS: + + The superblock is only searched in the blocks 9, 15, 18, which + corresponds to the beginning of track 1 on floppy disks. No support + for this FS on hard disk yet. + + +These filesystems are rather similar. Here is a comparison with Minix FS: + +* Linux fdisk reports on partitions + + - Minix FS 0x81 Linux/Minix + - Xenix FS ?? + - SystemV FS ?? + - Coherent FS 0x08 AIX bootable + +* Size of a block or zone (data allocation unit on disk) + + - Minix FS 1024 + - Xenix FS 1024 (also 512 ??) + - SystemV FS 1024 (also 512 and 2048) + - Coherent FS 512 + +* General layout: all have one boot block, one super block and + separate areas for inodes and for directories/data. + On SystemV Release 2 FS (e.g. Microport) the first track is reserved and + all the block numbers (including the super block) are offset by one track. + +* Byte ordering of "short" (16 bit entities) on disk: + + - Minix FS little endian 0 1 + - Xenix FS little endian 0 1 + - SystemV FS little endian 0 1 + - Coherent FS little endian 0 1 + + Of course, this affects only the file system, not the data of files on it! + +* Byte ordering of "long" (32 bit entities) on disk: + + - Minix FS little endian 0 1 2 3 + - Xenix FS little endian 0 1 2 3 + - SystemV FS little endian 0 1 2 3 + - Coherent FS PDP-11 2 3 0 1 + + Of course, this affects only the file system, not the data of files on it! + +* Inode on disk: "short", 0 means non-existent, the root dir ino is: + + ================================= == + Minix FS 1 + Xenix FS, SystemV FS, Coherent FS 2 + ================================= == + +* Maximum number of hard links to a file: + + =========== ========= + Minix FS 250 + Xenix FS ?? + SystemV FS ?? + Coherent FS >=10000 + =========== ========= + +* Free inode management: + + - Minix FS + a bitmap + - Xenix FS, SystemV FS, Coherent FS + There is a cache of a certain number of free inodes in the super-block. + When it is exhausted, new free inodes are found using a linear search. + +* Free block management: + + - Minix FS + a bitmap + - Xenix FS, SystemV FS, Coherent FS + Free blocks are organized in a "free list". Maybe a misleading term, + since it is not true that every free block contains a pointer to + the next free block. Rather, the free blocks are organized in chunks + of limited size, and every now and then a free block contains pointers + to the free blocks pertaining to the next chunk; the first of these + contains pointers and so on. The list terminates with a "block number" + 0 on Xenix FS and SystemV FS, with a block zeroed out on Coherent FS. + +* Super-block location: + + =========== ========================== + Minix FS block 1 = bytes 1024..2047 + Xenix FS block 1 = bytes 1024..2047 + SystemV FS bytes 512..1023 + Coherent FS block 1 = bytes 512..1023 + =========== ========================== + +* Super-block layout: + + - Minix FS:: + + unsigned short s_ninodes; + unsigned short s_nzones; + unsigned short s_imap_blocks; + unsigned short s_zmap_blocks; + unsigned short s_firstdatazone; + unsigned short s_log_zone_size; + unsigned long s_max_size; + unsigned short s_magic; + + - Xenix FS, SystemV FS, Coherent FS:: + + unsigned short s_firstdatazone; + unsigned long s_nzones; + unsigned short s_fzone_count; + unsigned long s_fzones[NICFREE]; + unsigned short s_finode_count; + unsigned short s_finodes[NICINOD]; + char s_flock; + char s_ilock; + char s_modified; + char s_rdonly; + unsigned long s_time; + short s_dinfo[4]; -- SystemV FS only + unsigned long s_free_zones; + unsigned short s_free_inodes; + short s_dinfo[4]; -- Xenix FS only + unsigned short s_interleave_m,s_interleave_n; -- Coherent FS only + char s_fname[6]; + char s_fpack[6]; + + then they differ considerably: + + Xenix FS:: + + char s_clean; + char s_fill[371]; + long s_magic; + long s_type; + + SystemV FS:: + + long s_fill[12 or 14]; + long s_state; + long s_magic; + long s_type; + + Coherent FS:: + + unsigned long s_unique; + + Note that Coherent FS has no magic. + +* Inode layout: + + - Minix FS:: + + unsigned short i_mode; + unsigned short i_uid; + unsigned long i_size; + unsigned long i_time; + unsigned char i_gid; + unsigned char i_nlinks; + unsigned short i_zone[7+1+1]; + + - Xenix FS, SystemV FS, Coherent FS:: + + unsigned short i_mode; + unsigned short i_nlink; + unsigned short i_uid; + unsigned short i_gid; + unsigned long i_size; + unsigned char i_zone[3*(10+1+1+1)]; + unsigned long i_atime; + unsigned long i_mtime; + unsigned long i_ctime; + + +* Regular file data blocks are organized as + + - Minix FS: + + - 7 direct blocks + - 1 indirect block (pointers to blocks) + - 1 double-indirect block (pointer to pointers to blocks) + + - Xenix FS, SystemV FS, Coherent FS: + + - 10 direct blocks + - 1 indirect block (pointers to blocks) + - 1 double-indirect block (pointer to pointers to blocks) + - 1 triple-indirect block (pointer to pointers to pointers to blocks) + + + =========== ========== ================ + Inode size inodes per block + =========== ========== ================ + Minix FS 32 32 + Xenix FS 64 16 + SystemV FS 64 16 + Coherent FS 64 8 + =========== ========== ================ + +* Directory entry on disk + + - Minix FS:: + + unsigned short inode; + char name[14/30]; + + - Xenix FS, SystemV FS, Coherent FS:: + + unsigned short inode; + char name[14]; + + =========== ============== ===================== + Dir entry size dir entries per block + =========== ============== ===================== + Minix FS 16/32 64/32 + Xenix FS 16 64 + SystemV FS 16 64 + Coherent FS 16 32 + =========== ============== ===================== + +* How to implement symbolic links such that the host fsck doesn't scream: + + - Minix FS normal + - Xenix FS kludge: as regular files with chmod 1000 + - SystemV FS ?? + - Coherent FS kludge: as regular files with chmod 1000 + + +Notation: We often speak of a "block" but mean a zone (the allocation unit) +and not the disk driver's notion of "block". -- cgit v1.2.3