This patch modifies parsing of mount options to allows passing units
along with the options. Valid units are "s" for seconds and "ms" for
milliseconds. When not specified, the unit defaults to seconds.
For example, "-o acdirmin=20ms" can be specified for 20 milliseconds,
and "-o acdirmin=3s" or just "-o acdirmin=3" for 3 seconds.
This code also changes the display of options in /proc/<pid>/mountstats
from seconds to milliseconds to reflect the accuracy.
Signed-off-by: Amit Gud <[email protected]>
Index: linux-2.6/fs/nfs/client.c
===================================================================
--- linux-2.6.orig/fs/nfs/client.c 2009-08-06 12:01:14.000000000 -0700
+++ linux-2.6/fs/nfs/client.c 2009-08-05 15:03:18.000000000 -0700
@@ -1295,10 +1295,10 @@
if (data->wsize)
server->wsize = nfs_block_size(data->wsize, NULL);
- server->acregmin = data->acregmin * HZ;
- server->acregmax = data->acregmax * HZ;
- server->acdirmin = data->acdirmin * HZ;
- server->acdirmax = data->acdirmax * HZ;
+ server->acregmin = (data->acregmin * HZ) / 1000;
+ server->acregmax = (data->acregmax * HZ) / 1000;
+ server->acdirmin = (data->acdirmin * HZ) / 1000;
+ server->acdirmax = (data->acdirmax * HZ) / 1000;
server->port = data->nfs_server.port;
Index: linux-2.6/fs/nfs/super.c
===================================================================
--- linux-2.6.orig/fs/nfs/super.c 2009-08-05 13:03:42.000000000 -0700
+++ linux-2.6/fs/nfs/super.c 2009-08-12 17:26:44.000000000 -0700
@@ -53,6 +53,7 @@
#include <linux/nfs_xdr.h>
#include <linux/magic.h>
#include <linux/parser.h>
+#include <linux/ctype.h>
#include <asm/system.h>
#include <asm/uaccess.h>
@@ -558,14 +559,14 @@
if (nfss->bsize != 0)
seq_printf(m, ",bsize=%u", nfss->bsize);
seq_printf(m, ",namlen=%u", nfss->namelen);
- if (nfss->acregmin != NFS_DEF_ACREGMIN*HZ || showdefaults)
- seq_printf(m, ",acregmin=%u", nfss->acregmin/HZ);
- if (nfss->acregmax != NFS_DEF_ACREGMAX*HZ || showdefaults)
- seq_printf(m, ",acregmax=%u", nfss->acregmax/HZ);
- if (nfss->acdirmin != NFS_DEF_ACDIRMIN*HZ || showdefaults)
- seq_printf(m, ",acdirmin=%u", nfss->acdirmin/HZ);
- if (nfss->acdirmax != NFS_DEF_ACDIRMAX*HZ || showdefaults)
- seq_printf(m, ",acdirmax=%u", nfss->acdirmax/HZ);
+ if (nfss->acregmin != (NFS_DEF_ACREGMIN * HZ) / 1000 || showdefaults)
+ seq_printf(m, ",acregmin=%u", (nfss->acregmin * 1000) / HZ);
+ if (nfss->acregmax != (NFS_DEF_ACREGMAX * HZ) / 1000 || showdefaults)
+ seq_printf(m, ",acregmax=%u", (nfss->acregmax * 1000) / HZ);
+ if (nfss->acdirmin != (NFS_DEF_ACDIRMIN * HZ) / 1000 || showdefaults)
+ seq_printf(m, ",acdirmin=%u", (nfss->acdirmin * 1000) / HZ);
+ if (nfss->acdirmax != (NFS_DEF_ACDIRMAX * HZ) / 1000 || showdefaults)
+ seq_printf(m, ",acdirmax=%u", (nfss->acdirmax * 1000) / HZ);
for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
if (nfss->flags & nfs_infop->flag)
seq_puts(m, nfs_infop->str);
@@ -967,6 +968,47 @@
}
/*
+ * Parse the input string for unit. Return the value which when
+ * multiplied with the user input yields millisecond resolution.
+ *
+ * If user does not specify any unit, it is defaulted to seconds.
+ */
+static unsigned int nfs_match_unit(char *string)
+{
+ unsigned int len = strlen(string);
+
+ if (len < 3)
+ return 1000;
+
+ string = string + len - 2;
+
+ if (!strcmp(string, "ms")) {
+ *string = '\0';
+ return 1;
+ }
+
+ string++;
+
+ if (isdigit(*string))
+ return 1000;
+
+ if (*string == 's') {
+ *string = '\0';
+ return 1000;
+ }
+
+ return 0;
+}
+
+/*
+ * This converts the user value in millisecond resolution.
+ */
+static inline unsigned long nfs_convert_unit(unsigned int unit, unsigned long option)
+{
+ return unit * option;
+}
+
+/*
* Error-check and convert a string of mount options from user space into
* a data structure. The whole mount string is processed; bad options are
* skipped as they are encountered. If there were no errors, return 1;
@@ -1003,6 +1045,7 @@
unsigned long option;
int int_option;
int token;
+ unsigned int unit;
if (!*p)
continue;
@@ -1174,52 +1217,57 @@
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
+ unit = nfs_match_unit(string);
rc = strict_strtoul(string, 10, &option);
kfree(string);
if (rc != 0)
goto out_invalid_value;
- mnt->acregmin = option;
+ mnt->acregmin = nfs_convert_unit(option, unit);
break;
case Opt_acregmax:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
+ unit = nfs_match_unit(string);
rc = strict_strtoul(string, 10, &option);
kfree(string);
if (rc != 0)
goto out_invalid_value;
- mnt->acregmax = option;
+ mnt->acregmax = nfs_convert_unit(option, unit);
break;
case Opt_acdirmin:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
+ unit = nfs_match_unit(string);
rc = strict_strtoul(string, 10, &option);
kfree(string);
if (rc != 0)
goto out_invalid_value;
- mnt->acdirmin = option;
+ mnt->acdirmin = nfs_convert_unit(option, unit);
break;
case Opt_acdirmax:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
+ unit = nfs_match_unit(string);
rc = strict_strtoul(string, 10, &option);
kfree(string);
if (rc != 0)
goto out_invalid_value;
- mnt->acdirmax = option;
+ mnt->acdirmax = nfs_convert_unit(option, unit);
break;
case Opt_actimeo:
string = match_strdup(args);
if (string == NULL)
goto out_nomem;
+ unit = nfs_match_unit(string);
rc = strict_strtoul(string, 10, &option);
kfree(string);
if (rc != 0)
goto out_invalid_value;
mnt->acregmin = mnt->acregmax =
- mnt->acdirmin = mnt->acdirmax = option;
+ mnt->acdirmin = mnt->acdirmax = nfs_convert_unit(option, unit);
break;
case Opt_namelen:
string = match_strdup(args);
@@ -1715,10 +1763,10 @@
args->wsize = data->wsize;
args->timeo = data->timeo;
args->retrans = data->retrans;
- args->acregmin = data->acregmin;
- args->acregmax = data->acregmax;
- args->acdirmin = data->acdirmin;
- args->acdirmax = data->acdirmax;
+ args->acregmin = data->acregmin * 1000;
+ args->acregmax = data->acregmax * 1000;
+ args->acdirmin = data->acdirmin * 1000;
+ args->acdirmax = data->acdirmax * 1000;
memcpy(&args->nfs_server.address, &data->addr,
sizeof(data->addr));
@@ -2391,10 +2439,10 @@
args->wsize = data->wsize;
args->timeo = data->timeo;
args->retrans = data->retrans;
- args->acregmin = data->acregmin;
- args->acregmax = data->acregmax;
- args->acdirmin = data->acdirmin;
- args->acdirmax = data->acdirmax;
+ args->acregmin = data->acregmin * 1000;
+ args->acregmax = data->acregmax * 1000;
+ args->acdirmin = data->acdirmin * 1000;
+ args->acdirmax = data->acdirmax * 1000;
args->nfs_server.protocol = data->proto;
nfs_validate_transport_protocol(args);
Index: linux-2.6/include/linux/nfs_fs.h
===================================================================
--- linux-2.6.orig/include/linux/nfs_fs.h 2009-08-05 18:45:16.000000000 -0700
+++ linux-2.6/include/linux/nfs_fs.h 2009-08-05 18:45:32.000000000 -0700
@@ -20,10 +20,10 @@
#define NFS_MAX_UDP_TIMEOUT (60*HZ)
#define NFS_MAX_TCP_TIMEOUT (600*HZ)
-#define NFS_DEF_ACREGMIN (3)
-#define NFS_DEF_ACREGMAX (60)
-#define NFS_DEF_ACDIRMIN (30)
-#define NFS_DEF_ACDIRMAX (60)
+#define NFS_DEF_ACREGMIN (3000)
+#define NFS_DEF_ACREGMAX (60000)
+#define NFS_DEF_ACDIRMIN (30000)
+#define NFS_DEF_ACDIRMAX (60000)
/*
* When flushing a cluster of dirty pages, there can be different
--
May the source be with you.
http://cis.ksu.edu~/gud
On Wed, 2009-08-12 at 17:47 -0700, Amit Gud wrote:
> This patch modifies parsing of mount options to allows passing units
> along with the options. Valid units are "s" for seconds and "ms" for
> milliseconds. When not specified, the unit defaults to seconds.
>
> For example, "-o acdirmin=20ms" can be specified for 20 milliseconds,
> and "-o acdirmin=3s" or just "-o acdirmin=3" for 3 seconds.
>
> This code also changes the display of options in /proc/<pid>/mountstats
> from seconds to milliseconds to reflect the accuracy.
This won't work. Suddenly the contents of /proc/self/mountinfo can no
longer be used as intended because acdirmin/max/... are being displayed
in milliseconds, whereas the default unit is in seconds.
Furthermore, you'll have rounding errors when converting backwards and
forwards into HZ, since the latter is usually > 1ms.
I agree with Neil. I think it would be better to use a 3 decimal fixed
point notation instead. Couldn't something like the following be made to
work?
static int nfs_parse_mstimeo(const char *str, unsigned long *res)
{
unsigned int msecs;
char *str2;
msecs = (unsigned int)simple_strtoul(str, &str2, 10);
msecs *= 1000;
/* Check if we're being given fixed point decimal notation */
if (*str2 == '.') {
unsigned long m;
size_t ndec = strlen(++str2);
/* Disallow more than 1/1000 precision */
if (ndec > 3)
goto out_inval;
if (strict_strtoul(str2, 10, &m))
goto out_inval;
switch (ndec) {
case 1:
m *= 10;
case 2:
m *= 10;
break;
}
msecs += (unsigned int)m;
} else if (*str2 != '\0' || str2 == str)
goto out_inval;
*res = msecs_to_jiffies(msecs);
return 0;
out_inval:
return -EINVAL;
}
static void nfs_display_mstimeo(struct seq_file *m, unsigned long val)
{
unsigned int msec = jiffies_to_msecs(val);
unsigned int rem = msec % 1000;
seq_printf(m, "%u", msec / 1000);
if (rem != 0)
seq_printf(m, ".%.3u", rem);
}
--
Trond Myklebust
Linux NFS client maintainer
NetApp
[email protected]
http://www.netapp.com