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authorLennart Poettering <lennart@poettering.net>2010-09-23 15:01:41 +0200
committerLennart Poettering <lennart@poettering.net>2010-09-23 15:02:13 +0200
commit22be093ffb403a1c474037939ca9b88b1ee39f77 (patch)
tree99b06c7fa271316661a2c3e2ea9bd69ff370a53f /src/readahead-common.c
parent647703fecb8c9928d0f13fd95d17fd5f2280c7e1 (diff)
readahead: implement minimal readahead logic based on fanotify(), mincore() and readahead()
Diffstat (limited to 'src/readahead-common.c')
-rw-r--r--src/readahead-common.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/src/readahead-common.c b/src/readahead-common.c
new file mode 100644
index 0000000000..8533717d47
--- /dev/null
+++ b/src/readahead-common.c
@@ -0,0 +1,107 @@
+/*-*- 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 <libudev.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "log.h"
+#include "readahead-common.h"
+#include "util.h"
+
+int file_verify(int fd, const char *fn, 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 > READAHEAD_FILE_SIZE_MAX) {
+ log_debug("Not preloading file %s with size out of bounds %zi", fn, 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 (!(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;
+}