pstore: use mount option instead sysfs to tweak kmsg_bytes (366f7e7a) · Commits · e / devices / android_kernel_xiaomi_markw

Documentation/ABI/testing/pstore

+9 −3

Original line number	Diff line number	Diff line
		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.

Documentation/ABI/testing/sysfs-fs-pstore

deleted100644 → 0

+0 −7

Original line number	Diff line number	Diff line
		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.

fs/pstore/inode.c

+46 −22

Original line number	Diff line number	Diff line
		@@ -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)

fs/pstore/internal.h

+1 −2

Original line number	Diff line number	Diff line
		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;

fs/pstore/platform.c

+3 −13

Original line number	Diff line number	Diff line
		@@ -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;