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-rw-r--r--fs/pstore/inode.c511
1 files changed, 511 insertions, 0 deletions
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
new file mode 100644
index 0000000000..585360706b
--- /dev/null
+++ b/fs/pstore/inode.c
@@ -0,0 +1,511 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Persistent Storage - ramfs parts.
+ *
+ * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
+ */
+
+#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/uaccess.h>
+
+#include "internal.h"
+
+#define PSTORE_NAMELEN 64
+
+static DEFINE_MUTEX(records_list_lock);
+static LIST_HEAD(records_list);
+
+static DEFINE_MUTEX(pstore_sb_lock);
+static struct super_block *pstore_sb;
+
+struct pstore_private {
+ struct list_head list;
+ struct dentry *dentry;
+ struct pstore_record *record;
+ size_t total_size;
+};
+
+struct pstore_ftrace_seq_data {
+ const void *ptr;
+ size_t off;
+ size_t size;
+};
+
+#define REC_SIZE sizeof(struct pstore_ftrace_record)
+
+static void free_pstore_private(struct pstore_private *private)
+{
+ if (!private)
+ return;
+ if (private->record) {
+ kvfree(private->record->buf);
+ kfree(private->record->priv);
+ kfree(private->record);
+ }
+ kfree(private);
+}
+
+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->total_size % REC_SIZE;
+ data->off += *pos * REC_SIZE;
+ if (data->off + REC_SIZE > ps->total_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;
+
+ (*pos)++;
+ data->off += REC_SIZE;
+ if (data->off + REC_SIZE > ps->total_size)
+ return NULL;
+
+ 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;
+
+ if (!data)
+ return 0;
+
+ rec = (struct pstore_ftrace_record *)(ps->record->buf + data->off);
+
+ seq_printf(s, "CPU:%d ts:%llu %08lx %08lx %ps <- %pS\n",
+ pstore_ftrace_decode_cpu(rec),
+ pstore_ftrace_read_timestamp(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 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->record->type == PSTORE_TYPE_FTRACE)
+ return seq_read(file, userbuf, count, ppos);
+ return simple_read_from_buffer(userbuf, count, ppos,
+ ps->record->buf, ps->total_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;
+
+ if (ps->record->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;
+ struct pstore_record *record = p->record;
+ int rc = 0;
+
+ if (!record->psi->erase)
+ return -EPERM;
+
+ /* Make sure we can't race while removing this file. */
+ mutex_lock(&records_list_lock);
+ if (!list_empty(&p->list))
+ list_del_init(&p->list);
+ else
+ rc = -ENOENT;
+ p->dentry = NULL;
+ mutex_unlock(&records_list_lock);
+ if (rc)
+ return rc;
+
+ mutex_lock(&record->psi->read_mutex);
+ record->psi->erase(record);
+ mutex_unlock(&record->psi->read_mutex);
+
+ return simple_unlink(dir, dentry);
+}
+
+static void pstore_evict_inode(struct inode *inode)
+{
+ struct pstore_private *p = inode->i_private;
+
+ clear_inode(inode);
+ free_pstore_private(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_set_ctime_current(inode);
+ }
+ 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;
+ }
+ }
+}
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int pstore_show_options(struct seq_file *m, struct dentry *root)
+{
+ if (kmsg_bytes != CONFIG_PSTORE_DEFAULT_KMSG_BYTES)
+ seq_printf(m, ",kmsg_bytes=%lu", kmsg_bytes);
+ return 0;
+}
+
+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 = pstore_show_options,
+};
+
+static struct dentry *psinfo_lock_root(void)
+{
+ struct dentry *root;
+
+ mutex_lock(&pstore_sb_lock);
+ /*
+ * Having no backend is fine -- no records appear.
+ * Not being mounted is fine -- nothing to do.
+ */
+ if (!psinfo || !pstore_sb) {
+ mutex_unlock(&pstore_sb_lock);
+ return NULL;
+ }
+
+ root = pstore_sb->s_root;
+ inode_lock(d_inode(root));
+ mutex_unlock(&pstore_sb_lock);
+
+ return root;
+}
+
+int pstore_put_backend_records(struct pstore_info *psi)
+{
+ struct pstore_private *pos, *tmp;
+ struct dentry *root;
+ int rc = 0;
+
+ root = psinfo_lock_root();
+ if (!root)
+ return 0;
+
+ mutex_lock(&records_list_lock);
+ list_for_each_entry_safe(pos, tmp, &records_list, list) {
+ if (pos->record->psi == psi) {
+ list_del_init(&pos->list);
+ rc = simple_unlink(d_inode(root), pos->dentry);
+ if (WARN_ON(rc))
+ break;
+ d_drop(pos->dentry);
+ dput(pos->dentry);
+ pos->dentry = NULL;
+ }
+ }
+ mutex_unlock(&records_list_lock);
+
+ inode_unlock(d_inode(root));
+
+ return rc;
+}
+
+/*
+ * 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(struct dentry *root, struct pstore_record *record)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+ int rc = 0;
+ char name[PSTORE_NAMELEN];
+ struct pstore_private *private, *pos;
+ size_t size = record->size + record->ecc_notice_size;
+
+ if (WARN_ON(!inode_is_locked(d_inode(root))))
+ return -EINVAL;
+
+ rc = -EEXIST;
+ /* Skip records that are already present in the filesystem. */
+ mutex_lock(&records_list_lock);
+ list_for_each_entry(pos, &records_list, list) {
+ if (pos->record->type == record->type &&
+ pos->record->id == record->id &&
+ pos->record->psi == record->psi)
+ goto fail;
+ }
+
+ rc = -ENOMEM;
+ inode = pstore_get_inode(root->d_sb);
+ if (!inode)
+ goto fail;
+ inode->i_mode = S_IFREG | 0444;
+ inode->i_fop = &pstore_file_operations;
+ scnprintf(name, sizeof(name), "%s-%s-%llu%s",
+ pstore_type_to_name(record->type),
+ record->psi->name, record->id,
+ record->compressed ? ".enc.z" : "");
+
+ private = kzalloc(sizeof(*private), GFP_KERNEL);
+ if (!private)
+ goto fail_inode;
+
+ dentry = d_alloc_name(root, name);
+ if (!dentry)
+ goto fail_private;
+
+ private->dentry = dentry;
+ private->record = record;
+ inode->i_size = private->total_size = size;
+ inode->i_private = private;
+
+ if (record->time.tv_sec)
+ inode->i_mtime = inode_set_ctime_to_ts(inode, record->time);
+
+ d_add(dentry, inode);
+
+ list_add(&private->list, &records_list);
+ mutex_unlock(&records_list_lock);
+
+ return 0;
+
+fail_private:
+ free_pstore_private(private);
+fail_inode:
+ iput(inode);
+fail:
+ mutex_unlock(&records_list_lock);
+ return rc;
+}
+
+/*
+ * Read all the records from the persistent store. Create
+ * files in our filesystem. Don't warn about -EEXIST errors
+ * when we are re-scanning the backing store looking to add new
+ * error records.
+ */
+void pstore_get_records(int quiet)
+{
+ struct dentry *root;
+
+ root = psinfo_lock_root();
+ if (!root)
+ return;
+
+ pstore_get_backend_records(psinfo, root, quiet);
+ inode_unlock(d_inode(root));
+}
+
+static int pstore_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *inode;
+
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_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 | 0750;
+ 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;
+
+ mutex_lock(&pstore_sb_lock);
+ pstore_sb = sb;
+ mutex_unlock(&pstore_sb_lock);
+
+ 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)
+{
+ mutex_lock(&pstore_sb_lock);
+ WARN_ON(pstore_sb && pstore_sb != sb);
+
+ kill_litter_super(sb);
+ pstore_sb = NULL;
+
+ mutex_lock(&records_list_lock);
+ INIT_LIST_HEAD(&records_list);
+ mutex_unlock(&records_list_lock);
+
+ mutex_unlock(&pstore_sb_lock);
+}
+
+static struct file_system_type pstore_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "pstore",
+ .mount = pstore_mount,
+ .kill_sb = pstore_kill_sb,
+};
+
+int __init pstore_init_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;
+}
+
+void __exit pstore_exit_fs(void)
+{
+ unregister_filesystem(&pstore_fs_type);
+ sysfs_remove_mount_point(fs_kobj, "pstore");
+}