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author | Lennart Poettering <lennart@poettering.net> | 2010-09-23 15:01:41 +0200 |
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committer | Lennart Poettering <lennart@poettering.net> | 2010-09-23 15:02:13 +0200 |
commit | 22be093ffb403a1c474037939ca9b88b1ee39f77 (patch) | |
tree | 99b06c7fa271316661a2c3e2ea9bd69ff370a53f /src/readahead-common.c | |
parent | 647703fecb8c9928d0f13fd95d17fd5f2280c7e1 (diff) | |
download | systemd-22be093ffb403a1c474037939ca9b88b1ee39f77.tar.gz |
readahead: implement minimal readahead logic based on fanotify(), mincore() and readahead()
Diffstat (limited to 'src/readahead-common.c')
-rw-r--r-- | src/readahead-common.c | 107 |
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; +} |