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https://github.com/kdave/btrfs-progs
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a223764093
Add wrappers around v1 and v2 of TREE_SEARCH ioctl so it can be transparently used by code. The structures partially overlap but due to the buffer size the v2 is offset and also needs a filler to expand the flexible buffer. Usage: - define struct btrfs_tree_search_args, all zeros - btrfs_tree_search_sk() reads offset of the search key within the structures - btrfs_tree_search_ioctl() detect support and call the highest supported ioctl version, v2 has been supported since 3.14 but we want to keep backward compatibility - btrfs_tree_search_data() read data from the buffer previously filled by ioctl, a sequence of (search header, data) Signed-off-by: David Sterba <dsterba@suse.com>
34 lines
885 B
C
34 lines
885 B
C
#ifndef __COMMON_TREE_SEARCH_H__
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#define __COMMON_TREE_SEARCH_H__
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#include "kernel-shared/uapi/btrfs_tree.h"
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#include "kernel-shared/uapi/btrfs.h"
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#define BTRFS_TREE_SEARCH_V2_BUF_SIZE 65536
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struct btrfs_tree_search_args {
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union {
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struct btrfs_ioctl_search_args args1;
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struct btrfs_ioctl_search_args_v2 args2;
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u8 filler[sizeof(struct btrfs_ioctl_search_args_v2) +
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BTRFS_TREE_SEARCH_V2_BUF_SIZE];
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};
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bool use_v2;
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};
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int btrfs_tree_search_ioctl(int fd, struct btrfs_tree_search_args *sa);
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static inline struct btrfs_ioctl_search_key *btrfs_tree_search_sk(struct btrfs_tree_search_args *sa)
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{
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/* Same offset for v1 and v2. */
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return &sa->args1.key;
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}
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static inline void *btrfs_tree_search_data(struct btrfs_tree_search_args *sa, unsigned long offset) {
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if (sa->use_v2)
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return (void *)(sa->args2.buf + offset);
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return (void *)(sa->args1.buf + offset);
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}
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#endif
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