Fork of Original Code Base: anongit.freedesktop.org/systemd

This is the initial fork of the code base from freedsktop.org.
The code is provided here as a reference of the initial starting
point and for possible future checkouts after a large portion
of this code is removed.

Merge git://anongit.freedesktop.org/systemd/systemd

1 files changed, 623 insertions, 0 deletions

diff --git a/src/readahead/readahead-collect.c b/src/readahead/readahead-collect.c
new file mode 100644
index 0000000000..5d07f4704a
--- /dev/null
+++ b/src/readahead/readahead-collect.c
@@ -0,0 +1,623 @@
+/*-*- 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>
+
+#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;
+
+/* 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;
+
+        zero(data);
+        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 = alloca(pages);
+        memset(vec, 0, 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);
+
+        if (fd >= 0)
+                close_nointr_nofail(fd);
+
+        return r;
+}
+
+static unsigned long fd_first_block(int fd) {
+        struct {
+                struct fiemap fiemap;
+                struct fiemap_extent extent;
+        } data;
+
+        zero(data);
+        data.fiemap.fm_length = ~0ULL;
+        data.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;
+};
+
+static int qsort_compare(const void *a, const void *b) {
+        const struct item *i, *j;
+
+        i = a;
+        j = b;
+
+        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;
+        }
+
+        /* 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;
+        }
+
+        if (!(files = hashmap_new(string_hash_func, string_compare_func))) {
+                log_error("Failed to allocate set.");
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        if ((fanotify_fd = fanotify_init(FAN_CLOEXEC|FAN_NONBLOCK, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME)) < 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;
+        }
+
+        if ((inotify_fd = open_inotify()) < 0) {
+                r = inotify_fd;
+                goto finish;
+        }
+
+        not_after = now(CLOCK_MONOTONIC) + arg_timeout;
+
+        my_pid = getpid();
+
+        zero(pollfd);
+        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;
+                        }
+                }
+
+                if ((n = read(fanotify_fd, &data, sizeof(data))) < 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[PATH_MAX];
+                        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);
+                        char_array_0(fn);
+
+                        if ((k = readlink_malloc(fn, &p)) >= 0) {
+                                if (startswith(p, "/tmp") ||
+                                    endswith(p, " (deleted)") ||
+                                    hashmap_get(files, p))
+                                        /* Not interesting, or
+                                         * already read */
+                                        free(p);
+                                else {
+                                        unsigned long ul;
+
+                                        ul = fd_first_block(m->fd);
+
+                                        if ((k = hashmap_put(files, p, SECTOR_TO_PTR(ul))) < 0) {
+                                                log_warning("set_put() failed: %s", strerror(-k));
+                                                free(p);
+                                        }
+                                }
+
+                        } else
+                                log_warning("readlink(%s) failed: %s", fn, strerror(-k));
+
+                next_iteration:
+                        if (m->fd >= 0)
+                                close_nointr_nofail(m->fd);
+                }
+        }
+
+done:
+        if (fanotify_fd >= 0) {
+                close_nointr_nofail(fanotify_fd);
+                fanotify_fd = -1;
+        }
+
+        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 && (long) sfs.f_type == (long) 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 {
+                struct item *ordered, *j;
+                unsigned k, n;
+
+                /* On rotating media, order things by the block
+                 * numbers */
+
+                log_debug("Ordering...");
+
+                n = hashmap_size(files);
+                if (!(ordered = new(struct item, n))) {
+                        r = log_oom();
+                        goto finish;
+                }
+
+                j = ordered;
+                HASHMAP_FOREACH_KEY(q, p, files, i) {
+                        j->path = p;
+                        j->block = PTR_TO_SECTOR(q);
+                        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);
+
+                free(ordered);
+        }
+
+        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:
+        if (fanotify_fd >= 0)
+                close_nointr_nofail(fanotify_fd);
+
+        if (signal_fd >= 0)
+                close_nointr_nofail(signal_fd);
+
+        if (inotify_fd >= 0)
+                close_nointr_nofail(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;
+}