From 366f7e7a79b19bd8c4e8f55fdf12b81538d1a7a4 Mon Sep 17 00:00:00 2001 From: "Luck, Tony" Date: Fri, 18 Mar 2011 15:33:43 -0700 Subject: [PATCH] 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: Christoph Hellwig Signed-off-by: Tony Luck Signed-off-by: Linus Torvalds --- Documentation/ABI/testing/pstore | 12 +++- Documentation/ABI/testing/sysfs-fs-pstore | 7 --- fs/pstore/inode.c | 68 +++++++++++++++-------- fs/pstore/internal.h | 3 +- fs/pstore/platform.c | 16 +----- 5 files changed, 59 insertions(+), 47 deletions(-) delete mode 100644 Documentation/ABI/testing/sysfs-fs-pstore diff --git a/Documentation/ABI/testing/pstore b/Documentation/ABI/testing/pstore index f1fb2a004264..ddf451ee2a08 100644 --- a/Documentation/ABI/testing/pstore +++ b/Documentation/ABI/testing/pstore @@ -1,6 +1,6 @@ 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. diff --git a/Documentation/ABI/testing/sysfs-fs-pstore b/Documentation/ABI/testing/sysfs-fs-pstore deleted file mode 100644 index 8e659d854805..000000000000 --- a/Documentation/ABI/testing/sysfs-fs-pstore +++ /dev/null @@ -1,7 +0,0 @@ -What: /sys/fs/pstore/kmsg_bytes -Date: January 2011 -Kernel Version: 2.6.38 -Contact: "Tony Luck" -Description: - Controls amount of console log that will be saved - to persistent store on oops/panic. diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index f777f2902c49..977ed2723845 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -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) diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h index 76c26d2fab29..8c9f23eb1645 100644 --- a/fs/pstore/internal.h +++ b/fs/pstore/internal.h @@ -1,7 +1,6 @@ +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; diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 705fdf8abf6e..ce9ad84d5dd9 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -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; -- 2.34.1