Commit 366f7e7a authored by Luck, Tony's avatar Luck, Tony Committed by Linus Torvalds

pstore: use mount option instead sysfs to tweak kmsg_bytes

/sys/fs is a somewhat strange way to tweak what could more
obviously be tuned with a mount option.
Suggested-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 10effcb5
Where: /dev/pstore/...
Date: January 2011
Kernel Version: 2.6.38
Date: March 2011
Kernel Version: 2.6.39
Contact: tony.luck@intel.com
Description: Generic interface to platform dependent persistent storage.
......@@ -11,7 +11,7 @@ Description: Generic interface to platform dependent persistent storage.
of the console log is captured, but other interesting
data can also be saved.
# mount -t pstore - /dev/pstore
# mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
$ ls -l /dev/pstore
total 0
......@@ -33,3 +33,9 @@ Description: Generic interface to platform dependent persistent storage.
will be saved elsewhere and erased from persistent store
soon after boot to free up space ready for the next
catastrophe.
The 'kmsg_bytes' mount option changes the target amount of
data saved on each oops/panic. Pstore saves (possibly
multiple) files based on the record size of the underlying
persistent storage until at least this amount is reached.
Default is 10 Kbytes.
What: /sys/fs/pstore/kmsg_bytes
Date: January 2011
Kernel Version: 2.6.38
Contact: "Tony Luck" <tony.luck@intel.com>
Description:
Controls amount of console log that will be saved
to persistent store on oops/panic.
......@@ -27,6 +27,7 @@
#include <linux/string.h>
#include <linux/mount.h>
#include <linux/ramfs.h>
#include <linux/parser.h>
#include <linux/sched.h>
#include <linux/magic.h>
#include <linux/pstore.h>
......@@ -112,10 +113,52 @@ static struct inode *pstore_get_inode(struct super_block *sb,
return inode;
}
enum {
Opt_kmsg_bytes, Opt_err
};
static const match_table_t tokens = {
{Opt_kmsg_bytes, "kmsg_bytes=%u"},
{Opt_err, NULL}
};
static void parse_options(char *options)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
if (!options)
return;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_kmsg_bytes:
if (!match_int(&args[0], &option))
pstore_set_kmsg_bytes(option);
break;
}
}
}
static int pstore_remount(struct super_block *sb, int *flags, char *data)
{
parse_options(data);
return 0;
}
static const struct super_operations pstore_ops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.evict_inode = pstore_evict_inode,
.remount_fs = pstore_remount,
.show_options = generic_show_options,
};
......@@ -215,6 +258,8 @@ int pstore_fill_super(struct super_block *sb, void *data, int silent)
sb->s_op = &pstore_ops;
sb->s_time_gran = 1;
parse_options(data);
inode = pstore_get_inode(sb, NULL, S_IFDIR | 0755, 0);
if (!inode) {
err = -ENOMEM;
......@@ -258,28 +303,7 @@ static struct file_system_type pstore_fs_type = {
static int __init init_pstore_fs(void)
{
int rc = 0;
struct kobject *pstorefs_kobj;
pstorefs_kobj = kobject_create_and_add("pstore", fs_kobj);
if (!pstorefs_kobj) {
rc = -ENOMEM;
goto done;
}
rc = sysfs_create_file(pstorefs_kobj, &pstore_kmsg_bytes_attr.attr);
if (rc)
goto done1;
rc = register_filesystem(&pstore_fs_type);
if (rc == 0)
goto done;
sysfs_remove_file(pstorefs_kobj, &pstore_kmsg_bytes_attr.attr);
done1:
kobject_put(pstorefs_kobj);
done:
return rc;
return register_filesystem(&pstore_fs_type);
}
module_init(init_pstore_fs)
......
extern void pstore_set_kmsg_bytes(int);
extern void pstore_get_records(void);
extern int pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
char *data, size_t size,
struct timespec time, int (*erase)(u64));
extern int pstore_is_mounted(void);
extern struct kobj_attribute pstore_kmsg_bytes_attr;
......@@ -37,24 +37,14 @@
static DEFINE_SPINLOCK(pstore_lock);
static struct pstore_info *psinfo;
/* How much of the console log to snapshot. /sys/fs/pstore/kmsg_bytes */
/* How much of the console log to snapshot */
static unsigned long kmsg_bytes = 10240;
static ssize_t b_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
void pstore_set_kmsg_bytes(int bytes)
{
return snprintf(buf, PAGE_SIZE, "%lu\n", kmsg_bytes);
kmsg_bytes = bytes;
}
static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
return (sscanf(buf, "%lu", &kmsg_bytes) > 0) ? count : 0;
}
struct kobj_attribute pstore_kmsg_bytes_attr =
__ATTR(kmsg_bytes, S_IRUGO | S_IWUSR, b_show, b_store);
/* Tag each group of saved records with a sequence number */
static int oopscount;
......
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