-/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
-
-/***
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-***/
-
-#include <errno.h>
-#include <inttypes.h>
-#include <fcntl.h>
-#include <linux/limits.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/select.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <linux/fanotify.h>
-#include <sys/signalfd.h>
-#include <sys/poll.h>
-#include <sys/mman.h>
-#include <linux/fs.h>
-#include <linux/fiemap.h>
-#include <sys/ioctl.h>
-#include <sys/vfs.h>
-#include <getopt.h>
-#include <sys/inotify.h>
-#include <math.h>
-
-#ifdef HAVE_LINUX_BTRFS_H
-#include <linux/btrfs.h>
-#endif
-
-#ifdef HAVE_FANOTIFY_INIT
-#include <sys/fanotify.h>
-#endif
-
-#include "systemd/sd-daemon.h"
-
-#include "missing.h"
-#include "util.h"
-#include "set.h"
-#include "ioprio.h"
-#include "readahead-common.h"
-#include "virt.h"
-
-/* fixme:
- *
- * - detect ssd on btrfs/lvm...
- * - read ahead directories
- * - gzip?
- * - remount rw?
- * - handle files where nothing is in mincore
- * - does ioprio_set work with fadvise()?
- */
-
-static ReadaheadShared *shared = NULL;
-static usec_t starttime;
-
-/* Avoid collisions with the NULL pointer */
-#define SECTOR_TO_PTR(s) ULONG_TO_PTR((s)+1)
-#define PTR_TO_SECTOR(p) (PTR_TO_ULONG(p)-1)
-
-static int btrfs_defrag(int fd) {
- struct btrfs_ioctl_vol_args data = { .fd = fd };
-
- return ioctl(fd, BTRFS_IOC_DEFRAG, &data);
-}
-
-static int pack_file(FILE *pack, const char *fn, bool on_btrfs) {
- struct stat st;
- void *start = MAP_FAILED;
- uint8_t *vec;
- uint32_t b, c;
- uint64_t inode;
- size_t l, pages;
- bool mapped;
- int r = 0, fd = -1, k;
-
- assert(pack);
- assert(fn);
-
- fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW);
- if (fd < 0) {
-
- if (errno == ENOENT)
- return 0;
-
- if (errno == EPERM || errno == EACCES)
- return 0;
-
- log_warning("open(%s) failed: %m", fn);
- r = -errno;
- goto finish;
- }
-
- k = file_verify(fd, fn, arg_file_size_max, &st);
- if (k <= 0) {
- r = k;
- goto finish;
- }
-
- if (on_btrfs)
- btrfs_defrag(fd);
-
- l = PAGE_ALIGN(st.st_size);
- start = mmap(NULL, l, PROT_READ, MAP_SHARED, fd, 0);
- if (start == MAP_FAILED) {
- log_warning("mmap(%s) failed: %m", fn);
- r = -errno;
- goto finish;
- }
-
- pages = l / page_size();
- vec = alloca0(pages);
- if (mincore(start, l, vec) < 0) {
- log_warning("mincore(%s) failed: %m", fn);
- r = -errno;
- goto finish;
- }
-
- fputs(fn, pack);
- fputc('\n', pack);
-
- /* Store the inode, so that we notice when the file is deleted */
- inode = (uint64_t) st.st_ino;
- fwrite(&inode, sizeof(inode), 1, pack);
-
- mapped = false;
- for (c = 0; c < pages; c++) {
- bool new_mapped = !!(vec[c] & 1);
-
- if (!mapped && new_mapped)
- b = c;
- else if (mapped && !new_mapped) {
- fwrite(&b, sizeof(b), 1, pack);
- fwrite(&c, sizeof(c), 1, pack);
-
- log_debug("%s: page %u to %u", fn, b, c);
- }
-
- mapped = new_mapped;
- }
-
- /* We don't write any range data if we should read the entire file */
- if (mapped && b > 0) {
- fwrite(&b, sizeof(b), 1, pack);
- fwrite(&c, sizeof(c), 1, pack);
-
- log_debug("%s: page %u to %u", fn, b, c);
- }
-
- /* End marker */
- b = 0;
- fwrite(&b, sizeof(b), 1, pack);
- fwrite(&b, sizeof(b), 1, pack);
-
-finish:
- if (start != MAP_FAILED)
- munmap(start, l);
-
- safe_close(fd);
-
- return r;
-}
-
-static unsigned long fd_first_block(int fd) {
- struct {
- struct fiemap fiemap;
- struct fiemap_extent extent;
- } data = {
- .fiemap.fm_length = ~0ULL,
- .fiemap.fm_extent_count = 1,
- };
-
- if (ioctl(fd, FS_IOC_FIEMAP, &data) < 0)
- return 0;
-
- if (data.fiemap.fm_mapped_extents <= 0)
- return 0;
-
- if (data.fiemap.fm_extents[0].fe_flags & FIEMAP_EXTENT_UNKNOWN)
- return 0;
-
- return (unsigned long) data.fiemap.fm_extents[0].fe_physical;
-}
-
-struct item {
- const char *path;
- unsigned long block;
- unsigned long bin;
-};
-
-static int qsort_compare(const void *a, const void *b) {
- const struct item *i, *j;
-
- i = a;
- j = b;
-
- /* sort by bin first */
- if (i->bin < j->bin)
- return -1;
- if (i->bin > j->bin)
- return 1;
-
- /* then sort by sector */
- if (i->block < j->block)
- return -1;
- if (i->block > j->block)
- return 1;
-
- return strcmp(i->path, j->path);
-}
-
-static int collect(const char *root) {
- enum {
- FD_FANOTIFY, /* Get the actual fs events */
- FD_SIGNAL,
- FD_INOTIFY, /* We get notifications to quit early via this fd */
- _FD_MAX
- };
- struct pollfd pollfd[_FD_MAX] = {};
- int fanotify_fd = -1, signal_fd = -1, inotify_fd = -1, r = 0;
- pid_t my_pid;
- Hashmap *files = NULL;
- Iterator i;
- char *p, *q;
- sigset_t mask;
- FILE *pack = NULL;
- char *pack_fn_new = NULL, *pack_fn = NULL;
- bool on_ssd, on_btrfs;
- struct statfs sfs;
- usec_t not_after;
- uint64_t previous_block_readahead;
- bool previous_block_readahead_set = false;
-
- assert(root);
-
- if (asprintf(&pack_fn, "%s/.readahead", root) < 0) {
- r = log_oom();
- goto finish;
- }
-
- starttime = now(CLOCK_MONOTONIC);
-
- /* If there's no pack file yet we lower the kernel readahead
- * so that mincore() is accurate. If there is a pack file
- * already we assume it is accurate enough so that kernel
- * readahead is never triggered. */
- previous_block_readahead_set =
- access(pack_fn, F_OK) < 0 &&
- block_get_readahead(root, &previous_block_readahead) >= 0 &&
- block_set_readahead(root, 8*1024) >= 0;
-
- if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)) < 0)
- log_warning("Failed to set IDLE IO priority class: %m");
-
- assert_se(sigemptyset(&mask) == 0);
- sigset_add_many(&mask, SIGINT, SIGTERM, -1);
- assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);
-
- if ((signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) {
- log_error("signalfd(): %m");
- r = -errno;
- goto finish;
- }
-
- files = hashmap_new(&string_hash_ops);
- if (!files) {
- log_error("Failed to allocate set.");
- r = -ENOMEM;
- goto finish;
- }
-
- fanotify_fd = fanotify_init(FAN_CLOEXEC|FAN_NONBLOCK, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME);
- if (fanotify_fd < 0) {
- log_error("Failed to create fanotify object: %m");
- r = -errno;
- goto finish;
- }
-
- if (fanotify_mark(fanotify_fd, FAN_MARK_ADD|FAN_MARK_MOUNT, FAN_OPEN, AT_FDCWD, root) < 0) {
- log_error("Failed to mark %s: %m", root);
- r = -errno;
- goto finish;
- }
-
- inotify_fd = open_inotify();
- if (inotify_fd < 0) {
- r = inotify_fd;
- goto finish;
- }
-
- not_after = now(CLOCK_MONOTONIC) + arg_timeout;
-
- my_pid = getpid();
-
- pollfd[FD_FANOTIFY].fd = fanotify_fd;
- pollfd[FD_FANOTIFY].events = POLLIN;
- pollfd[FD_SIGNAL].fd = signal_fd;
- pollfd[FD_SIGNAL].events = POLLIN;
- pollfd[FD_INOTIFY].fd = inotify_fd;
- pollfd[FD_INOTIFY].events = POLLIN;
-
- sd_notify(0,
- "READY=1\n"
- "STATUS=Collecting readahead data");
-
- log_debug("Collecting...");
-
- if (access("/run/systemd/readahead/cancel", F_OK) >= 0) {
- log_debug("Collection canceled");
- r = -ECANCELED;
- goto finish;
- }
-
- if (access("/run/systemd/readahead/done", F_OK) >= 0) {
- log_debug("Got termination request");
- goto done;
- }
-
- for (;;) {
- union {
- struct fanotify_event_metadata metadata;
- char buffer[4096];
- } data;
- ssize_t n;
- struct fanotify_event_metadata *m;
- usec_t t;
- int h;
-
- if (hashmap_size(files) > arg_files_max) {
- log_debug("Reached maximum number of read ahead files, ending collection.");
- break;
- }
-
- t = now(CLOCK_MONOTONIC);
- if (t >= not_after) {
- log_debug("Reached maximum collection time, ending collection.");
- break;
- }
-
- if ((h = poll(pollfd, _FD_MAX, (int) ((not_after - t) / USEC_PER_MSEC))) < 0) {
-
- if (errno == EINTR)
- continue;
-
- log_error("poll(): %m");
- r = -errno;
- goto finish;
- }
-
- if (h == 0) {
- log_debug("Reached maximum collection time, ending collection.");
- break;
- }
-
- if (pollfd[FD_SIGNAL].revents) {
- log_debug("Got signal.");
- break;
- }
-
- if (pollfd[FD_INOTIFY].revents) {
- uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
- struct inotify_event *e;
-
- if ((n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer))) < 0) {
- if (errno == EINTR || errno == EAGAIN)
- continue;
-
- log_error("Failed to read inotify event: %m");
- r = -errno;
- goto finish;
- }
-
- e = (struct inotify_event*) inotify_buffer;
- while (n > 0) {
- size_t step;
-
- if ((e->mask & IN_CREATE) && streq(e->name, "cancel")) {
- log_debug("Collection canceled");
- r = -ECANCELED;
- goto finish;
- }
-
- if ((e->mask & IN_CREATE) && streq(e->name, "done")) {
- log_debug("Got termination request");
- goto done;
- }
-
- step = sizeof(struct inotify_event) + e->len;
- assert(step <= (size_t) n);
-
- e = (struct inotify_event*) ((uint8_t*) e + step);
- n -= step;
- }
- }
-
- n = read(fanotify_fd, &data, sizeof(data));
- if (n < 0) {
-
- if (errno == EINTR || errno == EAGAIN)
- continue;
-
- /* fanotify sometimes returns EACCES on read()
- * where it shouldn't. For now let's just
- * ignore it here (which is safe), but
- * eventually this should be
- * dropped when the kernel is fixed.
- *
- * https://bugzilla.redhat.com/show_bug.cgi?id=707577 */
- if (errno == EACCES)
- continue;
-
- log_error("Failed to read event: %m");
- r = -errno;
- goto finish;
- }
-
- for (m = &data.metadata; FAN_EVENT_OK(m, n); m = FAN_EVENT_NEXT(m, n)) {
- char fn[sizeof("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
- int k;
-
- if (m->fd < 0)
- goto next_iteration;
-
- if (m->pid == my_pid)
- goto next_iteration;
-
- __sync_synchronize();
- if (m->pid == shared->replay)
- goto next_iteration;
-
- snprintf(fn, sizeof(fn), "/proc/self/fd/%i", m->fd);
- k = readlink_malloc(fn, &p);
- if (k >= 0) {
- if (startswith(p, "/tmp") ||
- endswith(p, " (deleted)") ||
- hashmap_get(files, p))
- /* Not interesting, or
- * already read */
- free(p);
- else {
- unsigned long ul;
- usec_t entrytime;
- struct item *entry;
-
- entry = new0(struct item, 1);
- if (!entry) {
- r = log_oom();
- goto finish;
- }
-
- ul = fd_first_block(m->fd);
-
- entrytime = now(CLOCK_MONOTONIC);
-
- entry->block = ul;
- entry->path = strdup(p);
- if (!entry->path) {
- free(entry);
- r = log_oom();
- goto finish;
- }
- entry->bin = (entrytime - starttime) / 2000000;
-
- k = hashmap_put(files, p, entry);
- if (k < 0) {
- log_warning("hashmap_put() failed: %s", strerror(-k));
- free(p);
- }
- }
-
- } else
- log_warning("readlink(%s) failed: %s", fn, strerror(-k));
-
- next_iteration:
- safe_close(m->fd);
- }
- }
-
-done:
- fanotify_fd = safe_close(fanotify_fd);
-
- log_debug("Writing Pack File...");
-
- on_ssd = fs_on_ssd(root) > 0;
- log_debug("On SSD: %s", yes_no(on_ssd));
-
- on_btrfs = statfs(root, &sfs) >= 0 && F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);
- log_debug("On btrfs: %s", yes_no(on_btrfs));
-
- if (asprintf(&pack_fn_new, "%s/.readahead.new", root) < 0) {
- r = log_oom();
- goto finish;
- }
-
- pack = fopen(pack_fn_new, "we");
- if (!pack) {
- log_error("Failed to open pack file: %m");
- r = -errno;
- goto finish;
- }
-
- fputs(CANONICAL_HOST READAHEAD_PACK_FILE_VERSION, pack);
- putc(on_ssd ? 'S' : 'R', pack);
-
- if (on_ssd || on_btrfs) {
-
- /* On SSD or on btrfs, just write things out in the
- * order the files were accessed. */
-
- HASHMAP_FOREACH_KEY(q, p, files, i)
- pack_file(pack, p, on_btrfs);
- } else {
- unsigned n;
-
- /* On rotating media, order things by the block
- * numbers */
-
- log_debug("Ordering...");
-
- n = hashmap_size(files);
- if (n) {
- _cleanup_free_ struct item *ordered;
- struct item *j;
- unsigned k;
-
- ordered = new(struct item, n);
- if (!ordered) {
- r = log_oom();
- goto finish;
- }
-
- j = ordered;
- HASHMAP_FOREACH_KEY(q, p, files, i) {
- memcpy(j, q, sizeof(struct item));
- j++;
- }
-
- assert(ordered + n == j);
-
- qsort(ordered, n, sizeof(struct item), qsort_compare);
-
- for (k = 0; k < n; k++)
- pack_file(pack, ordered[k].path, on_btrfs);
- } else
- log_warning("No pack files");
- }
-
- log_debug("Finalizing...");
-
- fflush(pack);
-
- if (ferror(pack)) {
- log_error("Failed to write pack file.");
- r = -EIO;
- goto finish;
- }
-
- if (rename(pack_fn_new, pack_fn) < 0) {
- log_error("Failed to rename readahead file: %m");
- r = -errno;
- goto finish;
- }
-
- fclose(pack);
- pack = NULL;
-
- log_debug("Done.");
-
-finish:
- safe_close(fanotify_fd);
- safe_close(signal_fd);
- safe_close(inotify_fd);
-
- if (pack) {
- fclose(pack);
- unlink(pack_fn_new);
- }
- free(pack_fn_new);
- free(pack_fn);
-
- while ((p = hashmap_steal_first_key(files)))
- free(p);
-
- hashmap_free(files);
-
- if (previous_block_readahead_set) {
- uint64_t bytes;
-
- /* Restore the original kernel readahead setting if we
- * changed it, and nobody has overwritten it since
- * yet. */
- if (block_get_readahead(root, &bytes) >= 0 && bytes == 8*1024)
- block_set_readahead(root, previous_block_readahead);
- }
-
- return r;
-}
-
-int main_collect(const char *root) {
-
- if (!root)
- root = "/";
-
- /* Skip this step on read-only media. Note that we check the
- * underlying block device here, not he read-only flag of the
- * file system on top, since that one is most likely mounted
- * read-only anyway at boot, even if the underlying block
- * device is theoretically writable. */
- if (fs_on_read_only(root) > 0) {
- log_info("Disabling readahead collector due to read-only media.");
- return EXIT_SUCCESS;
- }
-
- if (!enough_ram()) {
- log_info("Disabling readahead collector due to low memory.");
- return EXIT_SUCCESS;
- }
-
- shared = shared_get();
- if (!shared)
- return EXIT_FAILURE;
-
- shared->collect = getpid();
- __sync_synchronize();
-
- if (collect(root) < 0)
- return EXIT_FAILURE;
-
- return EXIT_SUCCESS;
-}
~ianmdlvl / elogind.git / commitdiff