ab1cb278bc
If loop block is mounted via 'mount -o loop', it isn't easy to pass file descriptor opened as O_DIRECT, so this patch introduces a new command to support direct IO for this case. Cc: linux-api@vger.kernel.org Signed-off-by: Ming Lei <ming.lei@canonical.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
/*
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* include/linux/loop.h
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*
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* Written by Theodore Ts'o, 3/29/93.
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*
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* Copyright 1993 by Theodore Ts'o. Redistribution of this file is
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* permitted under the GNU General Public License.
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*/
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#ifndef _UAPI_LINUX_LOOP_H
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#define _UAPI_LINUX_LOOP_H
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#define LO_NAME_SIZE 64
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#define LO_KEY_SIZE 32
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/*
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* Loop flags
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*/
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enum {
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LO_FLAGS_READ_ONLY = 1,
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LO_FLAGS_AUTOCLEAR = 4,
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LO_FLAGS_PARTSCAN = 8,
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LO_FLAGS_DIRECT_IO = 16,
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};
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#include <asm/posix_types.h> /* for __kernel_old_dev_t */
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#include <linux/types.h> /* for __u64 */
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/* Backwards compatibility version */
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struct loop_info {
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int lo_number; /* ioctl r/o */
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__kernel_old_dev_t lo_device; /* ioctl r/o */
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unsigned long lo_inode; /* ioctl r/o */
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__kernel_old_dev_t lo_rdevice; /* ioctl r/o */
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int lo_offset;
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int lo_encrypt_type;
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int lo_encrypt_key_size; /* ioctl w/o */
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int lo_flags; /* ioctl r/o */
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char lo_name[LO_NAME_SIZE];
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unsigned char lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
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unsigned long lo_init[2];
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char reserved[4];
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};
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struct loop_info64 {
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__u64 lo_device; /* ioctl r/o */
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__u64 lo_inode; /* ioctl r/o */
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__u64 lo_rdevice; /* ioctl r/o */
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__u64 lo_offset;
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__u64 lo_sizelimit;/* bytes, 0 == max available */
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__u32 lo_number; /* ioctl r/o */
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__u32 lo_encrypt_type;
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__u32 lo_encrypt_key_size; /* ioctl w/o */
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__u32 lo_flags; /* ioctl r/o */
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__u8 lo_file_name[LO_NAME_SIZE];
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__u8 lo_crypt_name[LO_NAME_SIZE];
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__u8 lo_encrypt_key[LO_KEY_SIZE]; /* ioctl w/o */
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__u64 lo_init[2];
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};
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/*
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* Loop filter types
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*/
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#define LO_CRYPT_NONE 0
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#define LO_CRYPT_XOR 1
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#define LO_CRYPT_DES 2
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#define LO_CRYPT_FISH2 3 /* Twofish encryption */
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#define LO_CRYPT_BLOW 4
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#define LO_CRYPT_CAST128 5
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#define LO_CRYPT_IDEA 6
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#define LO_CRYPT_DUMMY 9
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#define LO_CRYPT_SKIPJACK 10
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#define LO_CRYPT_CRYPTOAPI 18
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#define MAX_LO_CRYPT 20
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/*
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* IOCTL commands --- we will commandeer 0x4C ('L')
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*/
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#define LOOP_SET_FD 0x4C00
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#define LOOP_CLR_FD 0x4C01
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#define LOOP_SET_STATUS 0x4C02
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#define LOOP_GET_STATUS 0x4C03
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#define LOOP_SET_STATUS64 0x4C04
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#define LOOP_GET_STATUS64 0x4C05
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#define LOOP_CHANGE_FD 0x4C06
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#define LOOP_SET_CAPACITY 0x4C07
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#define LOOP_SET_DIRECT_IO 0x4C08
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/* /dev/loop-control interface */
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#define LOOP_CTL_ADD 0x4C80
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#define LOOP_CTL_REMOVE 0x4C81
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#define LOOP_CTL_GET_FREE 0x4C82
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#endif /* _UAPI_LINUX_LOOP_H */
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