282 lines
8.4 KiB
C
282 lines
8.4 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 Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 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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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser 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 <getopt.h>
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#include <sys/inotify.h>
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#include "systemd/sd-daemon.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 "ioprio.h"
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#include "readahead-common.h"
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#include "virt.h"
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static ReadaheadShared *shared = NULL;
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static int unpack_file(FILE *pack) {
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_cleanup_close_ int fd = -1;
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char fn[PATH_MAX];
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bool any = false;
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struct stat st;
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uint64_t inode;
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assert(pack);
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if (!fgets(fn, sizeof(fn), pack))
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return 0;
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char_array_0(fn);
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truncate_nl(fn);
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fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW);
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if (fd < 0) {
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if (errno != ENOENT && errno != EPERM && errno != EACCES && errno != ELOOP)
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log_warning("open(%s) failed: %m", fn);
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} else if (file_verify(fd, fn, arg_file_size_max, &st) <= 0)
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fd = safe_close(fd);
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if (fread(&inode, sizeof(inode), 1, pack) != 1) {
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log_error("Premature end of pack file.");
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return -EIO;
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}
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if (fd >= 0) {
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/* If the inode changed the file got deleted, so just
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* ignore this entry */
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if (st.st_ino != (uint64_t) inode)
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fd = safe_close(fd);
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}
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for (;;) {
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uint32_t b, c;
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if (fread(&b, sizeof(b), 1, pack) != 1 ||
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fread(&c, sizeof(c), 1, pack) != 1) {
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log_error("Premature end of pack file.");
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return -EIO;
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}
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if (b == 0 && c == 0)
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break;
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if (c <= b) {
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log_error("Invalid pack file.");
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return -EIO;
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}
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log_debug("%s: page %u to %u", fn, b, c);
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any = true;
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if (fd >= 0) {
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if (posix_fadvise(fd, b * page_size(), (c - b) * page_size(), POSIX_FADV_WILLNEED) < 0) {
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log_warning("posix_fadvise() failed: %m");
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return -errno;
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}
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}
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}
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if (!any && fd >= 0) {
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/* if no range is encoded in the pack file this is
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* intended to mean that the whole file shall be
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* read */
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if (posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED) < 0) {
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log_warning("posix_fadvise() failed: %m");
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return -errno;
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}
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}
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return 0;
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}
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static int replay(const char *root) {
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_cleanup_close_ int inotify_fd = -1;
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_cleanup_free_ char *pack_fn = NULL;
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_cleanup_fclose_ FILE *pack = NULL;
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bool on_ssd, ready = false;
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char line[LINE_MAX];
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int prio, c;
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assert(root);
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block_bump_request_nr(root);
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if (asprintf(&pack_fn, "%s/.readahead", root) < 0)
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return log_oom();
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pack = fopen(pack_fn, "re");
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if (!pack) {
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if (errno == ENOENT) {
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log_debug("No pack file found.");
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return 0;
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}
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log_error("Failed to open pack file: %m");
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return -errno;
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}
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posix_fadvise(fileno(pack), 0, 0, POSIX_FADV_WILLNEED);
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inotify_fd = open_inotify();
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if (inotify_fd < 0)
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return inotify_fd;
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if (!fgets(line, sizeof(line), pack)) {
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log_error("Premature end of pack file.");
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return -EIO;
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}
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char_array_0(line);
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if (!streq(line, CANONICAL_HOST READAHEAD_PACK_FILE_VERSION)) {
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log_debug("Pack file host or version type mismatch.");
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goto done;
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}
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c = getc(pack);
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if (c == EOF) {
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log_debug("Premature end of pack file.");
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return -EIO;
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}
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/* We do not retest SSD here, so that we can start replaying
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* before udev is up.*/
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on_ssd = c == 'S';
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log_debug("On SSD: %s", yes_no(on_ssd));
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if (on_ssd)
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prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
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else
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/* We are not using RT here, since we'd starve IO that
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we didn't record (which is for example blkid, since
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its disk accesses go directly to the block device and
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are thus not visible in fallocate) to death. However,
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we do ask for an IO prio that is slightly higher than
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the default (which is BE. 4) */
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prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 2);
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if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), prio) < 0)
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log_warning("Failed to set IDLE IO priority class: %m");
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sd_notify(0, "STATUS=Replaying readahead data");
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log_debug("Replaying...");
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if (access("/run/systemd/readahead/noreplay", F_OK) >= 0) {
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log_debug("Got termination request");
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goto done;
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}
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while (!feof(pack) && !ferror(pack)) {
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uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
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int k;
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ssize_t n;
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n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer));
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if (n < 0) {
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if (errno != EINTR && errno != EAGAIN) {
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log_error("Failed to read inotify event: %m");
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return -errno;
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}
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} else {
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struct inotify_event *e = (struct inotify_event*) inotify_buffer;
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while (n > 0) {
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size_t step;
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if ((e->mask & IN_CREATE) && streq(e->name, "noreplay")) {
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log_debug("Got termination request");
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goto done;
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}
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step = sizeof(struct inotify_event) + e->len;
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assert(step <= (size_t) n);
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e = (struct inotify_event*) ((uint8_t*) e + step);
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n -= step;
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}
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}
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k = unpack_file(pack);
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if (k < 0)
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return k;
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if (!ready) {
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/* We delay the ready notification until we
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* queued at least one read */
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sd_notify(0, "READY=1");
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ready = true;
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}
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}
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done:
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if (ferror(pack)) {
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log_error("Failed to read pack file.");
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return -EIO;
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}
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if (!ready)
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sd_notify(0, "READY=1");
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log_debug("Done.");
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return 0;
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}
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int main_replay(const char *root) {
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if (!root)
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root = "/";
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if (!enough_ram()) {
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log_info("Disabling readahead replay due to low memory.");
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return EXIT_SUCCESS;
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}
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shared = shared_get();
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if (!shared)
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return EXIT_FAILURE;
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shared->replay = getpid();
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__sync_synchronize();
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if (replay(root) < 0)
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return EXIT_FAILURE;
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return EXIT_SUCCESS;
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}
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