1 files changed, 269 insertions, 0 deletions
diff --git a/src/readahead/readahead-common.c b/src/readahead/readahead-common.c
new file mode 100644
index 000000000..67214ec37
--- /dev/null
+++ b/src/readahead/readahead-common.c
@@ -0,0 +1,269 @@
+/*-*- 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 General Public License as published by
+  the Free Software Foundation; either version 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/sysinfo.h>
+#include <sys/inotify.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <libudev.h>
+
+#include "log.h"
+#include "readahead-common.h"
+#include "util.h"
+
+int file_verify(int fd, const char *fn, off_t file_size_max, struct stat *st) {
+        assert(fd >= 0);
+        assert(fn);
+        assert(st);
+
+        if (fstat(fd, st) < 0) {
+                log_warning("fstat(%s) failed: %m", fn);
+                return -errno;
+        }
+
+        if (!S_ISREG(st->st_mode)) {
+                log_debug("Not preloading special file %s", fn);
+                return 0;
+        }
+
+        if (st->st_size <= 0 || st->st_size > file_size_max) {
+                log_debug("Not preloading file %s with size out of bounds %llu", fn, (unsigned long long) st->st_size);
+                return 0;
+        }
+
+        return 1;
+}
+
+int fs_on_ssd(const char *p) {
+        struct stat st;
+        struct udev *udev = NULL;
+        struct udev_device *udev_device = NULL, *look_at = NULL;
+        bool b = false;
+        const char *devtype, *rotational, *model, *id;
+
+        assert(p);
+
+        if (stat(p, &st) < 0)
+                return -errno;
+
+        if (major(st.st_dev) == 0)
+                return false;
+
+        if (!(udev = udev_new()))
+                return -ENOMEM;
+
+        if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev)))
+                goto finish;
+
+        if ((devtype = udev_device_get_property_value(udev_device, "DEVTYPE")) &&
+            streq(devtype, "partition"))
+                look_at = udev_device_get_parent(udev_device);
+        else
+                look_at = udev_device;
+
+        if (!look_at)
+                goto finish;
+
+        /* First, try high-level property */
+        if ((id = udev_device_get_property_value(look_at, "ID_SSD"))) {
+                b = streq(id, "1");
+                goto finish;
+        }
+
+        /* Second, try kernel attribute */
+        if ((rotational = udev_device_get_sysattr_value(look_at, "queue/rotational")))
+                if ((b = streq(rotational, "0")))
+                        goto finish;
+
+        /* Finally, fallback to heuristics */
+        if (!(look_at = udev_device_get_parent(look_at)))
+                goto finish;
+
+        if ((model = udev_device_get_sysattr_value(look_at, "model")))
+                b = !!strstr(model, "SSD");
+
+finish:
+        if (udev_device)
+                udev_device_unref(udev_device);
+
+        if (udev)
+                udev_unref(udev);
+
+        return b;
+}
+
+int fs_on_read_only(const char *p) {
+        struct stat st;
+        struct udev *udev = NULL;
+        struct udev_device *udev_device = NULL;
+        bool b = false;
+        const char *read_only;
+
+        assert(p);
+
+        if (stat(p, &st) < 0)
+                return -errno;
+
+        if (major(st.st_dev) == 0)
+                return false;
+
+        if (!(udev = udev_new()))
+                return -ENOMEM;
+
+        if (!(udev_device = udev_device_new_from_devnum(udev, 'b', st.st_dev)))
+                goto finish;
+
+        if ((read_only = udev_device_get_sysattr_value(udev_device, "ro")))
+                if ((b = streq(read_only, "1")))
+                        goto finish;
+
+finish:
+        if (udev_device)
+                udev_device_unref(udev_device);
+
+        if (udev)
+                udev_unref(udev);
+
+        return b;
+}
+
+bool enough_ram(void) {
+        struct sysinfo si;
+
+        assert_se(sysinfo(&si) >= 0);
+
+        /* Enable readahead only with at least 128MB memory */
+        return si.totalram > 127 * 1024*1024 / si.mem_unit;
+}
+
+int open_inotify(void) {
+        int fd;
+
+        if ((fd = inotify_init1(IN_CLOEXEC|IN_NONBLOCK)) < 0) {
+                log_error("Failed to create inotify handle: %m");
+                return -errno;
+        }
+
+        mkdir("/run/systemd", 0755);
+        mkdir("/run/systemd/readahead", 0755);
+
+        if (inotify_add_watch(fd, "/run/systemd/readahead", IN_CREATE) < 0) {
+                log_error("Failed to watch /run/systemd/readahead: %m");
+                close_nointr_nofail(fd);
+                return -errno;
+        }
+
+        return fd;
+}
+
+ReadaheadShared *shared_get(void) {
+        int fd;
+        ReadaheadShared *m = NULL;
+
+        mkdir("/run/systemd", 0755);
+        mkdir("/run/systemd/readahead", 0755);
+
+        if ((fd = open("/run/systemd/readahead/shared", O_CREAT|O_RDWR|O_CLOEXEC, 0644)) < 0) {
+                log_error("Failed to create shared memory segment: %m");
+                goto finish;
+        }
+
+        if (ftruncate(fd, sizeof(ReadaheadShared)) < 0) {
+                log_error("Failed to truncate shared memory segment: %m");
+                goto finish;
+        }
+
+        if ((m = mmap(NULL, sizeof(ReadaheadShared), PROT_WRITE|PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {
+                log_error("Failed to mmap shared memory segment: %m");
+                m = NULL;
+                goto finish;
+        }
+
+finish:
+        if (fd >= 0)
+                close_nointr_nofail(fd);
+
+        return m;
+}
+
+#define BUMP_REQUEST_NR (16*1024)
+
+int bump_request_nr(const char *p) {
+        struct stat st;
+        uint64_t u;
+        char *ap = NULL, *line = NULL;
+        int r;
+        dev_t d;
+
+        assert(p);
+
+        if (stat(p, &st) < 0)
+                return -errno;
+
+        if (major(st.st_dev) == 0)
+                return 0;
+
+        d = st.st_dev;
+        block_get_whole_disk(d, &d);
+
+        if (asprintf(&ap, "/sys/dev/block/%u:%u/queue/nr_requests", major(d), minor(d)) < 0) {
+                r= -ENOMEM;
+                goto finish;
+        }
+
+        r = read_one_line_file(ap, &line);
+        if (r < 0) {
+                if (r == -ENOENT)
+                        r = 0;
+                goto finish;
+        }
+
+        r = safe_atou64(line, &u);
+        if (r >= 0 && u >= BUMP_REQUEST_NR) {
+                r = 0;
+                goto finish;
+        }
+
+        free(line);
+        line = NULL;
+
+        if (asprintf(&line, "%lu", (unsigned long) BUMP_REQUEST_NR) < 0) {
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        r = write_one_line_file(ap, line);
+        if (r < 0)
+                goto finish;
+
+        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);
+        r = 1;
+
+finish:
+        free(ap);
+        free(line);
+
+        return r;
+}