@@ -1352,6 +1352,16 @@ config BOOT_CONFIG
If unsure, say Y.
+config INITRAMFS_PRESERVE_MTIME
+ bool "Preserve cpio archive mtimes in initramfs"
+ default y
+ help
+ Each entry in an initramfs cpio archive carries an mtime value. When
+ enabled, extracted cpio items take this mtime, with directory mtime
+ setting deferred until after creation of any child entries.
+
+ If unsure, say Y.
+
choice
prompt "Compiler optimization level"
default CC_OPTIMIZE_FOR_PERFORMANCE
@@ -17,6 +17,8 @@
#include <linux/init_syscalls.h>
#include <linux/umh.h>
+#include "initramfs_mtime.h"
+
static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
loff_t *pos)
{
@@ -116,46 +118,6 @@ static void __init free_hash(void)
}
}
-static long __init do_utime(char *filename, time64_t mtime)
-{
- struct timespec64 t[2];
-
- t[0].tv_sec = mtime;
- t[0].tv_nsec = 0;
- t[1].tv_sec = mtime;
- t[1].tv_nsec = 0;
- return init_utimes(filename, t);
-}
-
-static __initdata LIST_HEAD(dir_list);
-struct dir_entry {
- struct list_head list;
- char *name;
- time64_t mtime;
-};
-
-static void __init dir_add(const char *name, time64_t mtime)
-{
- struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
- if (!de)
- panic_show_mem("can't allocate dir_entry buffer");
- INIT_LIST_HEAD(&de->list);
- de->name = kstrdup(name, GFP_KERNEL);
- de->mtime = mtime;
- list_add(&de->list, &dir_list);
-}
-
-static void __init dir_utime(void)
-{
- struct dir_entry *de, *tmp;
- list_for_each_entry_safe(de, tmp, &dir_list, list) {
- list_del(&de->list);
- do_utime(de->name, de->mtime);
- kfree(de->name);
- kfree(de);
- }
-}
-
static __initdata time64_t mtime;
/* cpio header parsing */
@@ -379,14 +341,10 @@ static int __init do_name(void)
static int __init do_copy(void)
{
if (byte_count >= body_len) {
- struct timespec64 t[2] = { };
if (xwrite(wfile, victim, body_len, &wfile_pos) != body_len)
error("write error");
- t[0].tv_sec = mtime;
- t[1].tv_sec = mtime;
- vfs_utimes(&wfile->f_path, t);
-
+ do_utime_path(&wfile->f_path, mtime);
fput(wfile);
eat(body_len);
state = SkipIt;
new file mode 100644
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifdef CONFIG_INITRAMFS_PRESERVE_MTIME
+static void __init do_utime(char *filename, time64_t mtime)
+{
+ struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
+ init_utimes(filename, t);
+}
+
+static void __init do_utime_path(const struct path *path, time64_t mtime)
+{
+ struct timespec64 t[2] = { { .tv_sec = mtime }, { .tv_sec = mtime } };
+ vfs_utimes(path, t);
+}
+
+static __initdata LIST_HEAD(dir_list);
+struct dir_entry {
+ struct list_head list;
+ char *name;
+ time64_t mtime;
+};
+
+static void __init dir_add(const char *name, time64_t mtime)
+{
+ struct dir_entry *de = kmalloc(sizeof(struct dir_entry), GFP_KERNEL);
+ if (!de)
+ panic("can't allocate dir_entry buffer");
+ INIT_LIST_HEAD(&de->list);
+ de->name = kstrdup(name, GFP_KERNEL);
+ de->mtime = mtime;
+ list_add(&de->list, &dir_list);
+}
+
+static void __init dir_utime(void)
+{
+ struct dir_entry *de, *tmp;
+
+ list_for_each_entry_safe(de, tmp, &dir_list, list) {
+ list_del(&de->list);
+ do_utime(de->name, de->mtime);
+ kfree(de->name);
+ kfree(de);
+ }
+}
+#else
+static void __init do_utime(char *filename, time64_t mtime) {}
+static void __init do_utime_path(const struct path *path, time64_t mtime) {}
+static void __init dir_add(const char *name, time64_t mtime) {}
+static void __init dir_utime(void) {}
+#endif
initramfs cpio mtime preservation, as implemented in commit 889d51a10712 ("initramfs: add option to preserve mtime from initramfs cpio images"), uses a linked list to defer directory mtime processing until after all other items in the cpio archive have been processed. This is done to ensure that parent directory mtimes aren't overwritten via subsequent child creation. Contrary to the 889d51a10712 commit message, the mtime preservation behaviour is unconditional. This change adds a new INITRAMFS_PRESERVE_MTIME Kconfig option, which can be used to disable on-by-default mtime retention and in turn speed up initramfs extraction, particularly for cpio archives with large directory counts. Benchmarks with a one million directory cpio archive extracted 20 times demonstrated: mean extraction time (s) std dev INITRAMFS_PRESERVE_MTIME=y 3.808 0.006 INITRAMFS_PRESERVE_MTIME unset 3.056 0.004 The above extraction times were measured using ftrace (initcall_finish - initcall_start) values for populate_rootfs() with initramfs_async disabled. Signed-off-by: David Disseldorp <ddiss@suse.de> --- init/Kconfig | 10 +++++++++ init/initramfs.c | 48 +++------------------------------------- init/initramfs_mtime.h | 50 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 63 insertions(+), 45 deletions(-) create mode 100644 init/initramfs_mtime.h