449 lines
12 KiB
C
449 lines
12 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <inttypes.h>
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#include <fcntl.h>
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#include <linux/limits.h>
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#include <stdbool.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 <sys/select.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <linux/fanotify.h>
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#include <sys/signalfd.h>
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#include <sys/poll.h>
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#include <sys/mman.h>
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#include <linux/fs.h>
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#include <linux/fiemap.h>
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#include <sys/ioctl.h>
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#include <sys/vfs.h>
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#include "missing.h"
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#include "util.h"
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#include "set.h"
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#include "sd-daemon.h"
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#include "ioprio.h"
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#include "readahead-common.h"
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#define MINCORE_VEC_SIZE (READAHEAD_FILE_SIZE_MAX/PAGE_SIZE)
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static int btrfs_defrag(int fd) {
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struct btrfs_ioctl_vol_args data;
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zero(data);
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data.fd = fd;
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return ioctl(fd, BTRFS_IOC_DEFRAG, &data);
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}
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static int pack_file(FILE *pack, const char *fn, bool on_btrfs) {
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struct stat st;
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void *start = MAP_FAILED;
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uint8_t vec[MINCORE_VEC_SIZE];
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uint32_t b, c;
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size_t l, pages;
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bool mapped;
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int r = 0, fd = -1, k;
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assert(pack);
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assert(fn);
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if ((fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW)) < 0) {
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log_warning("open(%s) failed: %m", fn);
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r = -errno;
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goto finish;
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}
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if ((k = file_verify(fd, fn, &st)) <= 0) {
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r = k;
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goto finish;
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}
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if (on_btrfs)
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btrfs_defrag(fd);
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l = PAGE_ALIGN(st.st_size);
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if ((start = mmap(NULL, l, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
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log_warning("mmap(%s) failed: %m", fn);
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r = -errno;
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goto finish;
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}
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if (mincore(start, l, vec) < 0) {
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log_warning("mincore(%s) failed: %m", fn);
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r = -errno;
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goto finish;
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}
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fputs(fn, pack);
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fputc('\n', pack);
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pages = l / PAGE_SIZE;
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mapped = false;
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for (c = 0; c < pages; c++) {
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bool new_mapped = (vec[c] & 1);
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if (!mapped && new_mapped)
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b = c;
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else if (mapped && !new_mapped) {
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fwrite(&b, sizeof(b), 1, pack);
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fwrite(&c, sizeof(c), 1, pack);
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log_debug("%s: page %u to %u", fn, b, c);
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}
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mapped = new_mapped;
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}
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/* We don't write any range data if we should read the entire file */
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if (mapped && b > 0) {
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fwrite(&b, sizeof(b), 1, pack);
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fwrite(&c, sizeof(c), 1, pack);
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log_debug("%s: page %u to %u", fn, b, c);
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}
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/* End marker */
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b = 0;
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fwrite(&b, sizeof(b), 1, pack);
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fwrite(&b, sizeof(b), 1, pack);
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finish:
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if (start != MAP_FAILED)
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munmap(start, l);
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if (fd >= 0)
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close_nointr_nofail(fd);
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return r;
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}
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static unsigned long fd_first_block(int fd) {
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struct {
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struct fiemap fiemap;
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struct fiemap_extent extent;
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} data;
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zero(data);
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data.fiemap.fm_length = ~0ULL;
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data.fiemap.fm_extent_count = 1;
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if (ioctl(fd, FS_IOC_FIEMAP, &data) < 0)
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return 0;
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if (data.fiemap.fm_mapped_extents <= 0)
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return 0;
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if (data.fiemap.fm_extents[0].fe_flags & FIEMAP_EXTENT_UNKNOWN)
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return 0;
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return (unsigned long) data.fiemap.fm_extents[0].fe_physical;
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}
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struct item {
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const char *path;
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unsigned long block;
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};
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static int qsort_compare(const void *a, const void *b) {
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const struct item *i, *j;
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i = a;
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j = b;
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if (i->block < j->block)
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return -1;
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if (i->block > j->block)
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return 1;
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return strcmp(i->path, j->path);
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}
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static int collect(const char *root) {
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enum {
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FD_FANOTIFY,
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FD_SIGNAL,
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_FD_MAX
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};
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struct pollfd pollfd[_FD_MAX];
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int fanotify_fd = -1, signal_fd = -1, r = 0;
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pid_t my_pid;
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Hashmap *files = NULL;
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Iterator i;
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char *p, *q;
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sigset_t mask;
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FILE *pack = NULL;
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char *pack_fn_new = NULL, *pack_fn = NULL;
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bool on_ssd, on_btrfs;
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struct statfs sfs;
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assert(root);
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if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)) < 0)
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log_warning("Failed to set IDLE IO priority class: %m");
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assert_se(sigemptyset(&mask) == 0);
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sigset_add_many(&mask, SIGINT, SIGTERM, -1);
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assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
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if ((signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) {
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log_error("signalfd(): %m");
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r = -errno;
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goto finish;
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}
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if (!(files = hashmap_new(string_hash_func, string_compare_func))) {
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log_error("Failed to allocate set.");
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r = -ENOMEM;
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goto finish;
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}
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if ((fanotify_fd = fanotify_init(FAN_CLOEXEC, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME)) < 0) {
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log_error("Failed to create fanotify object: %m");
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r = -errno;
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goto finish;
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}
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if (fanotify_mark(fanotify_fd, FAN_MARK_ADD|FAN_MARK_MOUNT, FAN_OPEN, AT_FDCWD, root) < 0) {
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log_error("Failed to mark %s: %m", root);
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r = -errno;
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goto finish;
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}
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my_pid = getpid();
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zero(pollfd);
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pollfd[FD_FANOTIFY].fd = fanotify_fd;
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pollfd[FD_FANOTIFY].events = POLLIN;
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pollfd[FD_SIGNAL].fd = signal_fd;
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pollfd[FD_SIGNAL].events = POLLIN;
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sd_notify(0,
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"READY=1\n"
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"STATUS=Collecting readahead data");
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log_debug("Collecting...");
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for (;;) {
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union {
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struct fanotify_event_metadata metadata;
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char buffer[4096];
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} data;
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ssize_t n;
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struct fanotify_event_metadata *m;
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if (hashmap_size(files) > READAHEAD_FILES_MAX)
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break;
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if (poll(pollfd, _FD_MAX, -1) < 0) {
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if (errno == EINTR)
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continue;
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log_error("poll(): %m");
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r = -errno;
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goto finish;
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}
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if (pollfd[FD_SIGNAL].revents != 0)
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break;
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if ((n = read(fanotify_fd, &data, sizeof(data))) < 0) {
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if (errno == EINTR || errno == EAGAIN)
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continue;
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log_error("Failed to read event: %m");
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r = -errno;
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goto finish;
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}
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m = &data.metadata;
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while (FAN_EVENT_OK(m, n)) {
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if (m->pid != my_pid && m->fd >= 0) {
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char fn[PATH_MAX];
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int k;
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snprintf(fn, sizeof(fn), "/proc/self/fd/%i", m->fd);
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char_array_0(fn);
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if ((k = readlink_malloc(fn, &p)) >= 0) {
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if (hashmap_get(files, p))
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/* Already read */
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free(p);
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else {
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unsigned long ul;
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ul = fd_first_block(m->fd);
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if ((k = hashmap_put(files, p, ULONG_TO_PTR(ul))) < 0) {
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if (k != -EEXIST)
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log_warning("set_put() failed: %s", strerror(-k));
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free(p);
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}
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}
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} else
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log_warning("readlink(%s) failed: %s", fn, strerror(-k));
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}
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if (m->fd)
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close_nointr_nofail(m->fd);
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m = FAN_EVENT_NEXT(m, n);
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}
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}
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if (fanotify_fd >= 0) {
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close_nointr_nofail(fanotify_fd);
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fanotify_fd = -1;
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}
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log_debug("Writing Pack File...");
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on_ssd = fs_on_ssd(root);
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log_debug("On SSD: %s", yes_no(on_ssd));
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on_btrfs = statfs(root, &sfs) >= 0 && sfs.f_type == BTRFS_SUPER_MAGIC;
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log_debug("On btrfs: %s", yes_no(on_btrfs));
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asprintf(&pack_fn, "%s/.readahead", root);
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asprintf(&pack_fn_new, "%s/.readahead.new", root);
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if (!pack_fn || !pack_fn_new) {
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log_error("Out of memory");
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r = -ENOMEM;
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goto finish;
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}
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if (!(pack = fopen(pack_fn_new, "we"))) {
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log_error("Failed to open pack file: %m");
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r = -errno;
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goto finish;
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}
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fputs(CANONICAL_HOST "\n", pack);
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putc(on_ssd ? 'S' : 'R', pack);
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if (on_ssd || on_btrfs) {
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/* On SSD or on btrfs, just write things out in the
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* order the files where accessed. */
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HASHMAP_FOREACH_KEY(q, p, files, i)
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pack_file(pack, p, on_btrfs);
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} else {
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struct item *ordered, *j;
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unsigned k, n;
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/* On rotating media, order things by the block
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* numbers */
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log_debug("Ordering...");
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n = hashmap_size(files);
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if (!(ordered = new(struct item, n))) {
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log_error("Out of memory");
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r = -ENOMEM;
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goto finish;
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}
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j = ordered;
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HASHMAP_FOREACH_KEY(q, p, files, i) {
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j->path = p;
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j->block = PTR_TO_ULONG(q);
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j++;
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}
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assert(ordered + n == j);
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qsort(ordered, n, sizeof(struct item), qsort_compare);
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for (k = 0; k < n; k++)
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pack_file(pack, ordered[k].path, on_btrfs);
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free(ordered);
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}
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log_debug("Finalizing...");
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fflush(pack);
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if (ferror(pack)) {
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log_error("Failed to write pack file.");
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r = -EIO;
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goto finish;
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}
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if (rename(pack_fn_new, pack_fn) < 0) {
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log_error("Failed to rename readahead file: %m");
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r = -errno;
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goto finish;
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}
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fclose(pack);
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pack = NULL;
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log_debug("Done.");
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finish:
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if (fanotify_fd >= 0)
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close_nointr_nofail(fanotify_fd);
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if (signal_fd >= 0)
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close_nointr_nofail(signal_fd);
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if (pack) {
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fclose(pack);
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unlink(pack_fn_new);
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}
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free(pack_fn_new);
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free(pack_fn);
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while ((p = hashmap_steal_first_key(files)))
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free(q);
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hashmap_free(files);
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return r;
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}
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int main(int argc, char *argv[]) {
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log_set_target(LOG_TARGET_SYSLOG_OR_KMSG);
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log_parse_environment();
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log_open();
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if (collect("/") < 0)
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return 1;
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return 0;
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}
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