On Mon, 2019-07-29 at 18:49 -0700, Deepa Dinamani wrote:
> The warning reuses the uptime max of 30 years used by the
> setitimeofday().
>
> Note that the warning is only added for new filesystem mounts
> through the mount syscall. Automounts do not have the same warning.
>
> Signed-off-by: Deepa Dinamani <deepa.kernel@xxxxxxxxx>
> ---
> fs/namespace.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/namespace.c b/fs/namespace.c
> index b26778bdc236..5314fac8035e 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2739,6 +2739,17 @@ static int do_new_mount_fc(struct fs_context *fc, struct path *mountpoint,
> error = do_add_mount(real_mount(mnt), mountpoint, mnt_flags);
> if (error < 0)
> mntput(mnt);
> +
> + if (!error && sb->s_time_max &&
I don't know why you are testing sb->s_time_max here - it should always
be non-zero since alloc_super() sets it to TIME64_MAX.
> + (ktime_get_real_seconds() + TIME_UPTIME_SEC_MAX > sb->s_time_max)) {
> + char *buf = (char *)__get_free_page(GFP_KERNEL);
> + char *mntpath = buf ? d_path(mountpoint, buf, PAGE_SIZE) : ERR_PTR(-ENOMEM);
> +
> + pr_warn("Mounted %s file system at %s supports timestamps until 0x%llx\n",
> + fc->fs_type->name, mntpath, (unsigned long long)sb->s_time_max);
This doesn't seem like a helpful way to log the time. Maybe use
time64_to_tm() to convert to "broken down" time and then print it with
"%ptR"... but that wants struct rtc_time. If you apply the attached
patch, however, you should then be able to print struct tm with
"%ptT".
Ben.
> + free_page((unsigned long)buf);
> + }
> +
> return error;
> }
>
--
Ben Hutchings, Software Developer Codethink Ltd
https://www.codethink.co.uk/ Dale House, 35 Dale Street
Manchester, M1 2HF, United Kingdom
From 40cd51356d366110d33b891a6b9f3a428ed4ab2e Mon Sep 17 00:00:00 2001
From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
Date: Mon, 5 Aug 2019 14:49:33 +0100
Subject: [PATCH] vsprintf: Add support for printing struct tm in
human-readable format
Change date_str(), time_str(), rtc_str() to take a struct tm (the main
kAPI type) instead of struct rtc_time (uAPI type), and rename rtc_str()
accordingly.
Change time_and_date() to accept either a struct rtc_time ('R') or
a struct tm ('T'), converting the former to the latter.
Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
---
Documentation/core-api/printk-formats.rst | 6 ++--
lib/vsprintf.c | 34 ++++++++++++++++-------
2 files changed, 27 insertions(+), 13 deletions(-)
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 75d2bbe9813f..fbae020bcc22 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -436,10 +436,10 @@ Time and date (struct rtc_time)
%ptR YYYY-mm-ddTHH:MM:SS
%ptRd YYYY-mm-dd
%ptRt HH:MM:SS
- %ptR[dt][r]
+ %pt[RT][dt][r]
-For printing date and time as represented by struct rtc_time structure in
-human readable format.
+For printing date and time as represented by struct rtc_time (R) or struct
+tm (T) structure in human readable format.
By default year will be incremented by 1900 and month by 1. Use %ptRr (raw)
to suppress this behaviour.
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 63937044c57d..dc32742876fd 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1699,7 +1699,7 @@ char *address_val(char *buf, char *end, const void *addr,
}
static noinline_for_stack
-char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
+char *date_str(char *buf, char *end, const struct tm *tm, bool r)
{
int year = tm->tm_year + (r ? 0 : 1900);
int mon = tm->tm_mon + (r ? 0 : 1);
@@ -1718,7 +1718,7 @@ char *date_str(char *buf, char *end, const struct rtc_time *tm, bool r)
}
static noinline_for_stack
-char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
+char *time_str(char *buf, char *end, const struct tm *tm, bool r)
{
buf = number(buf, end, tm->tm_hour, default_dec02_spec);
if (buf < end)
@@ -1734,16 +1734,13 @@ char *time_str(char *buf, char *end, const struct rtc_time *tm, bool r)
}
static noinline_for_stack
-char *rtc_str(char *buf, char *end, const struct rtc_time *tm,
- struct printf_spec spec, const char *fmt)
+char *struct_tm_str(char *buf, char *end, const struct tm *tm,
+ struct printf_spec spec, const char *fmt)
{
bool have_t = true, have_d = true;
bool raw = false;
int count = 2;
- if (check_pointer(&buf, end, tm, spec))
- return buf;
-
switch (fmt[count]) {
case 'd':
have_t = false;
@@ -1775,11 +1772,28 @@ static noinline_for_stack
char *time_and_date(char *buf, char *end, void *ptr, struct printf_spec spec,
const char *fmt)
{
+ if (check_pointer(&buf, end, ptr, spec))
+ return buf;
+
switch (fmt[1]) {
- case 'R':
- return rtc_str(buf, end, (const struct rtc_time *)ptr, spec, fmt);
+ case 'R': {
+ const struct rtc_time *rtm = (const struct rtc_time *)ptr;
+ struct tm tm = {
+ .tm_sec = rtm->tm_sec,
+ .tm_min = rtm->tm_min,
+ .tm_hour = rtm->tm_hour,
+ .tm_mday = rtm->tm_mday,
+ .tm_mon = rtm->tm_mon,
+ .tm_year = rtm->tm_year,
+ };
+
+ return struct_tm_str(buf, end, &tm, spec, fmt);
+ }
+ case 'T':
+ return struct_tm_str(buf, end, (const struct tm *)ptr,
+ spec, fmt);
default:
- return error_string(buf, end, "(%ptR?)", spec);
+ return error_string(buf, end, "(%pt?)", spec);
}
}
--
Ben Hutchings, Software Developer Codethink Ltd
https://www.codethink.co.uk/ Dale House, 35 Dale Street
Manchester, M1 2HF, United Kingdom
