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Edit File: nbd.h
/* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */ /* * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL. * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne) * Made nbd_end_request() use the io_request_lock * 2001 Copyright (C) Steven Whitehouse * New nbd_end_request() for compatibility with new linux block * layer code. * 2003/06/24 Louis D. Langholtz <ldl@aros.net> * Removed unneeded blksize_bits field from nbd_device struct. * Cleanup PARANOIA usage & code. * 2004/02/19 Paul Clements * Removed PARANOIA, plus various cleanup and comments * 2023 Copyright Red Hat * Link to userspace extensions, favor cookie over handle. */ #ifndef LINUX_NBD_H #define LINUX_NBD_H #include <linux/types.h> #define NBD_SET_SOCK _IO( 0xab, 0 ) #define NBD_SET_BLKSIZE _IO( 0xab, 1 ) #define NBD_SET_SIZE _IO( 0xab, 2 ) #define NBD_DO_IT _IO( 0xab, 3 ) #define NBD_CLEAR_SOCK _IO( 0xab, 4 ) #define NBD_CLEAR_QUE _IO( 0xab, 5 ) #define NBD_PRINT_DEBUG _IO( 0xab, 6 ) #define NBD_SET_SIZE_BLOCKS _IO( 0xab, 7 ) #define NBD_DISCONNECT _IO( 0xab, 8 ) #define NBD_SET_TIMEOUT _IO( 0xab, 9 ) #define NBD_SET_FLAGS _IO( 0xab, 10) /* * See also https://github.com/NetworkBlockDevice/nbd/blob/master/doc/proto.md * for additional userspace extensions not yet utilized in the kernel module. */ enum { NBD_CMD_READ = 0, NBD_CMD_WRITE = 1, NBD_CMD_DISC = 2, NBD_CMD_FLUSH = 3, NBD_CMD_TRIM = 4, /* userspace defines additional extension commands */ NBD_CMD_WRITE_ZEROES = 6, }; /* values for flags field, these are server interaction specific. */ #define NBD_FLAG_HAS_FLAGS (1 << 0) /* nbd-server supports flags */ #define NBD_FLAG_READ_ONLY (1 << 1) /* device is read-only */ #define NBD_FLAG_SEND_FLUSH (1 << 2) /* can flush writeback cache */ #define NBD_FLAG_SEND_FUA (1 << 3) /* send FUA (forced unit access) */ #define NBD_FLAG_ROTATIONAL (1 << 4) /* device is rotational */ #define NBD_FLAG_SEND_TRIM (1 << 5) /* send trim/discard */ #define NBD_FLAG_SEND_WRITE_ZEROES (1 << 6) /* supports WRITE_ZEROES */ /* there is a gap here to match userspace */ #define NBD_FLAG_CAN_MULTI_CONN (1 << 8) /* Server supports multiple connections per export. */ /* values for cmd flags in the upper 16 bits of request type */ #define NBD_CMD_FLAG_FUA (1 << 16) /* FUA (forced unit access) op */ #define NBD_CMD_FLAG_NO_HOLE (1 << 17) /* Do not punch a hole for WRITE_ZEROES */ /* These are client behavior specific flags. */ #define NBD_CFLAG_DESTROY_ON_DISCONNECT (1 << 0) /* delete the nbd device on disconnect. */ #define NBD_CFLAG_DISCONNECT_ON_CLOSE (1 << 1) /* disconnect the nbd device on * close by last opener. */ /* userspace doesn't need the nbd_device structure */ /* These are sent over the network in the request/reply magic fields */ #define NBD_REQUEST_MAGIC 0x25609513 #define NBD_REPLY_MAGIC 0x67446698 /* Do *not* use magics: 0x12560953 0x96744668. */ /* magic 0x668e33ef for structured reply not supported by kernel yet */ /* * This is the packet used for communication between client and * server. All data are in network byte order. */ struct nbd_request { __be32 magic; /* NBD_REQUEST_MAGIC */ __be32 type; /* See NBD_CMD_* */ union { __be64 cookie; /* Opaque identifier for request */ char handle[8]; /* older spelling of cookie */ }; __be64 from; __be32 len; } __attribute__((packed)); /* * This is the reply packet that nbd-server sends back to the client after * it has completed an I/O request (or an error occurs). */ struct nbd_reply { __be32 magic; /* NBD_REPLY_MAGIC */ __be32 error; /* 0 = ok, else error */ union { __be64 cookie; /* Opaque identifier from request */ char handle[8]; /* older spelling of cookie */ }; }; #endif /* LINUX_NBD_H */