From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/pstore/inode.c | 511 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 511 insertions(+) create mode 100644 fs/pstore/inode.c (limited to 'fs/pstore/inode.c') diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c new file mode 100644 index 000000000..ffbadb8b3 --- /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 + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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) { + kfree(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->i_ctime = current_time(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->i_ctime = 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"); +} -- cgit v1.2.3