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571a4b62ed
It seems that 9pfs does not allow truncating unlinked files, Mark Brown has noted that NFS may also behave this way. It doesn't seem quite right to call this a "bug" but it's probably a special enough case that it makes sense for the test to just SKIP if it happens. Link: https://lkml.kernel.org/r/20250311-mm-selftests-v4-7-dec210a658f5@google.com Signed-off-by: Brendan Jackman <jackmanb@google.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
128 lines
2.9 KiB
C
128 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2018 Dmitry Safonov, Arista Networks
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*
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* MAP_POPULATE | MAP_PRIVATE should COW VMA pages.
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*/
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/mman.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "../kselftest.h"
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#define MMAP_SZ 4096
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#define BUG_ON(condition, description) \
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do { \
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if (condition) \
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ksft_exit_fail_msg("[FAIL]\t%s:%d\t%s:%s\n", \
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__func__, __LINE__, (description), \
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strerror(errno)); \
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} while (0)
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#define TESTS_IN_CHILD 2
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static void parent_f(int sock, unsigned long *smap, int child)
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{
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int status, ret;
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ret = read(sock, &status, sizeof(int));
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BUG_ON(ret <= 0, "read(sock)");
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*smap = 0x22222BAD;
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ret = msync(smap, MMAP_SZ, MS_SYNC);
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BUG_ON(ret, "msync()");
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ret = write(sock, &status, sizeof(int));
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BUG_ON(ret <= 0, "write(sock)");
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waitpid(child, &status, 0);
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/* The ksft macros don't keep counters between processes */
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ksft_cnt.ksft_pass = WEXITSTATUS(status);
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ksft_cnt.ksft_fail = TESTS_IN_CHILD - WEXITSTATUS(status);
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}
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static int child_f(int sock, unsigned long *smap, int fd)
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{
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int ret, buf = 0;
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smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_POPULATE, fd, 0);
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BUG_ON(smap == MAP_FAILED, "mmap()");
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BUG_ON(*smap != 0xdeadbabe, "MAP_PRIVATE | MAP_POPULATE changed file");
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ret = write(sock, &buf, sizeof(int));
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BUG_ON(ret <= 0, "write(sock)");
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ret = read(sock, &buf, sizeof(int));
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BUG_ON(ret <= 0, "read(sock)");
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ksft_test_result(*smap != 0x22222BAD, "MAP_POPULATE COW private page\n");
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ksft_test_result(*smap == 0xdeadbabe, "The mapping state\n");
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/* The ksft macros don't keep counters between processes */
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return ksft_cnt.ksft_pass;
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}
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int main(int argc, char **argv)
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{
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int sock[2], child, ret;
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FILE *ftmp;
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unsigned long *smap;
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ksft_print_header();
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ksft_set_plan(TESTS_IN_CHILD);
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ftmp = tmpfile();
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BUG_ON(!ftmp, "tmpfile()");
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ret = ftruncate(fileno(ftmp), MMAP_SZ);
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if (ret < 0 && errno == ENOENT) {
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/*
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* This probably means tmpfile() made a file on a filesystem
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* that doesn't handle temporary files the way we want.
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*/
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ksft_exit_skip("ftruncate(fileno(tmpfile())) gave ENOENT, weird filesystem?\n");
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}
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BUG_ON(ret, "ftruncate()");
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smap = mmap(0, MMAP_SZ, PROT_READ | PROT_WRITE,
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MAP_SHARED, fileno(ftmp), 0);
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BUG_ON(smap == MAP_FAILED, "mmap()");
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*smap = 0xdeadbabe;
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/* Probably unnecessary, but let it be. */
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ret = msync(smap, MMAP_SZ, MS_SYNC);
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BUG_ON(ret, "msync()");
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ret = socketpair(PF_LOCAL, SOCK_SEQPACKET, 0, sock);
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BUG_ON(ret, "socketpair()");
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child = fork();
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BUG_ON(child == -1, "fork()");
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if (child) {
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ret = close(sock[0]);
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BUG_ON(ret, "close()");
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parent_f(sock[1], smap, child);
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ksft_finished();
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}
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ret = close(sock[1]);
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BUG_ON(ret, "close()");
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return child_f(sock[0], smap, fileno(ftmp));
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}
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