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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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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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#include <sys/sysinfo.h>
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#include <sys/inotify.h>
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#include "readahead-common.h"
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int file_verify(int fd, const char *fn, off_t file_size_max, struct stat *st) {
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if (fstat(fd, st) < 0) {
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log_warning("fstat(%s) failed: %m", fn);
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if (!S_ISREG(st->st_mode)) {
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log_debug("Not preloading special file %s", fn);
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if (st->st_size <= 0 || st->st_size > file_size_max) {
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log_debug("Not preloading file %s with size out of bounds %llu", fn, (unsigned long long) st->st_size);
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int fs_on_ssd(const char *p) {
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struct udev *udev = NULL;
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struct udev_device *udev_device = NULL, *look_at = NULL;
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const char *devtype, *rotational, *model, *id;
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if (major(st.st_dev) == 0)
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if (!(udev = udev_new()))
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if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev)))
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if ((devtype = udev_device_get_property_value(udev_device, "DEVTYPE")) &&
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streq(devtype, "partition"))
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look_at = udev_device_get_parent(udev_device);
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look_at = udev_device;
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/* First, try high-level property */
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if ((id = udev_device_get_property_value(look_at, "ID_SSD"))) {
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/* Second, try kernel attribute */
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if ((rotational = udev_device_get_sysattr_value(look_at, "queue/rotational")))
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if ((b = streq(rotational, "0")))
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/* Finally, fallback to heuristics */
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if (!(look_at = udev_device_get_parent(look_at)))
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if ((model = udev_device_get_sysattr_value(look_at, "model")))
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b = !!strstr(model, "SSD");
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udev_device_unref(udev_device);
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int fs_on_read_only(const char *p) {
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struct udev *udev = NULL;
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struct udev_device *udev_device = NULL;
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const char *read_only;
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if (stat(p, &st) < 0)
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if (major(st.st_dev) == 0)
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if (!(udev = udev_new()))
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if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev)))
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if ((read_only = udev_device_get_sysattr_value(udev_device, "ro")))
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if ((b = streq(read_only, "1")))
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udev_device_unref(udev_device);
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bool enough_ram(void) {
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assert_se(sysinfo(&si) >= 0);
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/* Enable readahead only with at least 128MB memory */
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return si.totalram > 127 * 1024*1024 / si.mem_unit;
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int open_inotify(void) {
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if ((fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
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log_error("Failed to create inotify handle: %m");
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mkdir("/run/systemd", 0755);
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mkdir("/run/systemd/readahead", 0755);
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if (inotify_add_watch(fd, "/run/systemd/readahead", IN_CREATE) < 0) {
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log_error("Failed to watch /run/systemd/readahead: %m");
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close_nointr_nofail(fd);
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ReadaheadShared *shared_get(void) {
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ReadaheadShared *m = NULL;
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mkdir("/run/systemd", 0755);
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mkdir("/run/systemd/readahead", 0755);
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if ((fd = open("/run/systemd/readahead/shared", O_CREAT|O_RDWR|O_CLOEXEC, 0644)) < 0) {
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log_error("Failed to create shared memory segment: %m");
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if (ftruncate(fd, sizeof(ReadaheadShared)) < 0) {
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log_error("Failed to truncate shared memory segment: %m");
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if ((m = mmap(NULL, sizeof(ReadaheadShared), PROT_WRITE|PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
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log_error("Failed to mmap shared memory segment: %m");
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close_nointr_nofail(fd);
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#define BUMP_REQUEST_NR (16*1024)
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int bump_request_nr(const char *p) {
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char *ap = NULL, *line = NULL;
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if (stat(p, &st) < 0)
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if (major(st.st_dev) == 0)
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block_get_whole_disk(d, &d);
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if (asprintf(&ap, "/sys/dev/block/%u:%u/queue/nr_requests", major(d), minor(d)) < 0) {
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r = read_one_line_file(ap, &line);
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r = safe_atou64(line, &u);
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if (r >= 0 && u >= BUMP_REQUEST_NR) {
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if (asprintf(&line, "%lu", (unsigned long) BUMP_REQUEST_NR) < 0) {
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r = write_one_line_file(ap, line);
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log_info("Bumped block_nr parameter of %u:%u to %lu. This is a temporary hack and should be removed one day.", major(d), minor(d), (unsigned long) BUMP_REQUEST_NR);