diff options
Diffstat (limited to 'kernel/fs/pstore/inode.c')
| -rw-r--r-- | kernel/fs/pstore/inode.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/kernel/fs/pstore/inode.c b/kernel/fs/pstore/inode.c new file mode 100644 index 000000000..3adcc4669 --- /dev/null +++ b/kernel/fs/pstore/inode.c @@ -0,0 +1,483 @@ +/* + * Persistent Storage - ramfs parts. + * + * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/fsnotify.h> +#include <linux/pagemap.h> +#include <linux/highmem.h> +#include <linux/time.h> +#include <linux/init.h> +#include <linux/list.h> +#include <linux/string.h> +#include <linux/mount.h> +#include <linux/seq_file.h> +#include <linux/ramfs.h> +#include <linux/parser.h> +#include <linux/sched.h> +#include <linux/magic.h> +#include <linux/pstore.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/uaccess.h> +#include <linux/syslog.h> + +#include "internal.h" + +#define PSTORE_NAMELEN 64 + +static DEFINE_SPINLOCK(allpstore_lock); +static LIST_HEAD(allpstore); + +struct pstore_private { + struct list_head list; + struct pstore_info *psi; + enum pstore_type_id type; + u64 id; + int count; + ssize_t size; + char data[]; +}; + +struct pstore_ftrace_seq_data { + const void *ptr; + size_t off; + size_t size; +}; + +#define REC_SIZE sizeof(struct pstore_ftrace_record) + +static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos) +{ + struct pstore_private *ps = s->private; + struct pstore_ftrace_seq_data *data; + + data = kzalloc(sizeof(*data), GFP_KERNEL); + if (!data) + return NULL; + + data->off = ps->size % REC_SIZE; + data->off += *pos * REC_SIZE; + if (data->off + REC_SIZE > ps->size) { + kfree(data); + return NULL; + } + + return data; + +} + +static void pstore_ftrace_seq_stop(struct seq_file *s, void *v) +{ + kfree(v); +} + +static void *pstore_ftrace_seq_next(struct seq_file *s, void *v, loff_t *pos) +{ + struct pstore_private *ps = s->private; + struct pstore_ftrace_seq_data *data = v; + + data->off += REC_SIZE; + if (data->off + REC_SIZE > ps->size) + return NULL; + + (*pos)++; + return data; +} + +static int pstore_ftrace_seq_show(struct seq_file *s, void *v) +{ + struct pstore_private *ps = s->private; + struct pstore_ftrace_seq_data *data = v; + struct pstore_ftrace_record *rec = (void *)(ps->data + data->off); + + seq_printf(s, "%d %08lx %08lx %pf <- %pF\n", + pstore_ftrace_decode_cpu(rec), rec->ip, rec->parent_ip, + (void *)rec->ip, (void *)rec->parent_ip); + + return 0; +} + +static const struct seq_operations pstore_ftrace_seq_ops = { + .start = pstore_ftrace_seq_start, + .next = pstore_ftrace_seq_next, + .stop = pstore_ftrace_seq_stop, + .show = pstore_ftrace_seq_show, +}; + +static int pstore_check_syslog_permissions(struct pstore_private *ps) +{ + switch (ps->type) { + case PSTORE_TYPE_DMESG: + case PSTORE_TYPE_CONSOLE: + return check_syslog_permissions(SYSLOG_ACTION_READ_ALL, + SYSLOG_FROM_READER); + default: + return 0; + } +} + +static ssize_t pstore_file_read(struct file *file, char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct seq_file *sf = file->private_data; + struct pstore_private *ps = sf->private; + + if (ps->type == PSTORE_TYPE_FTRACE) + return seq_read(file, userbuf, count, ppos); + return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size); +} + +static int pstore_file_open(struct inode *inode, struct file *file) +{ + struct pstore_private *ps = inode->i_private; + struct seq_file *sf; + int err; + const struct seq_operations *sops = NULL; + + err = pstore_check_syslog_permissions(ps); + if (err) + return err; + + if (ps->type == PSTORE_TYPE_FTRACE) + sops = &pstore_ftrace_seq_ops; + + err = seq_open(file, sops); + if (err < 0) + return err; + + sf = file->private_data; + sf->private = ps; + + return 0; +} + +static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence) +{ + struct seq_file *sf = file->private_data; + + if (sf->op) + return seq_lseek(file, off, whence); + return default_llseek(file, off, whence); +} + +static const struct file_operations pstore_file_operations = { + .open = pstore_file_open, + .read = pstore_file_read, + .llseek = pstore_file_llseek, + .release = seq_release, +}; + +/* + * When a file is unlinked from our file system we call the + * platform driver to erase the record from persistent store. + */ +static int pstore_unlink(struct inode *dir, struct dentry *dentry) +{ + struct pstore_private *p = d_inode(dentry)->i_private; + int err; + + err = pstore_check_syslog_permissions(p); + if (err) + return err; + + if (p->psi->erase) + p->psi->erase(p->type, p->id, p->count, + d_inode(dentry)->i_ctime, p->psi); + else + return -EPERM; + + return simple_unlink(dir, dentry); +} + +static void pstore_evict_inode(struct inode *inode) +{ + struct pstore_private *p = inode->i_private; + unsigned long flags; + + clear_inode(inode); + if (p) { + spin_lock_irqsave(&allpstore_lock, flags); + list_del(&p->list); + spin_unlock_irqrestore(&allpstore_lock, flags); + kfree(p); + } +} + +static const struct inode_operations pstore_dir_inode_operations = { + .lookup = simple_lookup, + .unlink = pstore_unlink, +}; + +static struct inode *pstore_get_inode(struct super_block *sb) +{ + struct inode *inode = new_inode(sb); + if (inode) { + inode->i_ino = get_next_ino(); + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + } + 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) +{ + sync_filesystem(sb); + 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, +}; + +static struct super_block *pstore_sb; + +int pstore_is_mounted(void) +{ + return pstore_sb != NULL; +} + +/* + * Make a regular file in the root directory of our file system. + * Load it up with "size" bytes of data from "buf". + * Set the mtime & ctime to the date that this record was originally stored. + */ +int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count, + char *data, bool compressed, size_t size, + struct timespec time, struct pstore_info *psi) +{ + struct dentry *root = pstore_sb->s_root; + struct dentry *dentry; + struct inode *inode; + int rc = 0; + char name[PSTORE_NAMELEN]; + struct pstore_private *private, *pos; + unsigned long flags; + + spin_lock_irqsave(&allpstore_lock, flags); + list_for_each_entry(pos, &allpstore, list) { + if (pos->type == type && + pos->id == id && + pos->psi == psi) { + rc = -EEXIST; + break; + } + } + spin_unlock_irqrestore(&allpstore_lock, flags); + if (rc) + return rc; + + rc = -ENOMEM; + inode = pstore_get_inode(pstore_sb); + if (!inode) + goto fail; + inode->i_mode = S_IFREG | 0444; + inode->i_fop = &pstore_file_operations; + private = kmalloc(sizeof *private + size, GFP_KERNEL); + if (!private) + goto fail_alloc; + private->type = type; + private->id = id; + private->count = count; + private->psi = psi; + + switch (type) { + case PSTORE_TYPE_DMESG: + scnprintf(name, sizeof(name), "dmesg-%s-%lld%s", + psname, id, compressed ? ".enc.z" : ""); + break; + case PSTORE_TYPE_CONSOLE: + scnprintf(name, sizeof(name), "console-%s-%lld", psname, id); + break; + case PSTORE_TYPE_FTRACE: + scnprintf(name, sizeof(name), "ftrace-%s-%lld", psname, id); + break; + case PSTORE_TYPE_MCE: + scnprintf(name, sizeof(name), "mce-%s-%lld", psname, id); + break; + case PSTORE_TYPE_PPC_RTAS: + scnprintf(name, sizeof(name), "rtas-%s-%lld", psname, id); + break; + case PSTORE_TYPE_PPC_OF: + scnprintf(name, sizeof(name), "powerpc-ofw-%s-%lld", + psname, id); + break; + case PSTORE_TYPE_PPC_COMMON: + scnprintf(name, sizeof(name), "powerpc-common-%s-%lld", + psname, id); + break; + case PSTORE_TYPE_PMSG: + scnprintf(name, sizeof(name), "pmsg-%s-%lld", psname, id); + break; + case PSTORE_TYPE_PPC_OPAL: + sprintf(name, "powerpc-opal-%s-%lld", psname, id); + break; + case PSTORE_TYPE_UNKNOWN: + scnprintf(name, sizeof(name), "unknown-%s-%lld", psname, id); + break; + default: + scnprintf(name, sizeof(name), "type%d-%s-%lld", + type, psname, id); + break; + } + + mutex_lock(&d_inode(root)->i_mutex); + + dentry = d_alloc_name(root, name); + if (!dentry) + goto fail_lockedalloc; + + memcpy(private->data, data, size); + inode->i_size = private->size = size; + + inode->i_private = private; + + if (time.tv_sec) + inode->i_mtime = inode->i_ctime = time; + + d_add(dentry, inode); + + spin_lock_irqsave(&allpstore_lock, flags); + list_add(&private->list, &allpstore); + spin_unlock_irqrestore(&allpstore_lock, flags); + + mutex_unlock(&d_inode(root)->i_mutex); + + return 0; + +fail_lockedalloc: + mutex_unlock(&d_inode(root)->i_mutex); + kfree(private); +fail_alloc: + iput(inode); + +fail: + return rc; +} + +static int pstore_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + + save_mount_options(sb, data); + + pstore_sb = sb; + + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = PSTOREFS_MAGIC; + sb->s_op = &pstore_ops; + sb->s_time_gran = 1; + + parse_options(data); + + inode = pstore_get_inode(sb); + if (inode) { + inode->i_mode = S_IFDIR | 0755; + inode->i_op = &pstore_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + inc_nlink(inode); + } + sb->s_root = d_make_root(inode); + if (!sb->s_root) + return -ENOMEM; + + pstore_get_records(0); + + return 0; +} + +static struct dentry *pstore_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return mount_single(fs_type, flags, data, pstore_fill_super); +} + +static void pstore_kill_sb(struct super_block *sb) +{ + kill_litter_super(sb); + pstore_sb = NULL; +} + +static struct file_system_type pstore_fs_type = { + .name = "pstore", + .mount = pstore_mount, + .kill_sb = pstore_kill_sb, +}; + +static int __init init_pstore_fs(void) +{ + int err; + + /* Create a convenient mount point for people to access pstore */ + err = sysfs_create_mount_point(fs_kobj, "pstore"); + if (err) + goto out; + + err = register_filesystem(&pstore_fs_type); + if (err < 0) + sysfs_remove_mount_point(fs_kobj, "pstore"); + +out: + return err; +} +module_init(init_pstore_fs) + +MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>"); +MODULE_LICENSE("GPL"); |