diff options
Diffstat (limited to 'arch/s390/hypfs/inode.c')
| -rw-r--r-- | arch/s390/hypfs/inode.c | 504 |
1 files changed, 504 insertions, 0 deletions
diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c new file mode 100644 index 000000000..ee919bfc8 --- /dev/null +++ b/arch/s390/hypfs/inode.c @@ -0,0 +1,504 @@ +// SPDX-License-Identifier: GPL-1.0+ +/* + * Hypervisor filesystem for Linux on s390. + * + * Copyright IBM Corp. 2006, 2008 + * Author(s): Michael Holzheu <holzheu@de.ibm.com> + */ + +#define KMSG_COMPONENT "hypfs" +#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt + +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/fs_context.h> +#include <linux/fs_parser.h> +#include <linux/namei.h> +#include <linux/vfs.h> +#include <linux/slab.h> +#include <linux/pagemap.h> +#include <linux/time.h> +#include <linux/sysfs.h> +#include <linux/init.h> +#include <linux/kobject.h> +#include <linux/seq_file.h> +#include <linux/uio.h> +#include <asm/ebcdic.h> +#include "hypfs.h" + +#define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */ +#define TMP_SIZE 64 /* size of temporary buffers */ + +static struct dentry *hypfs_create_update_file(struct dentry *dir); + +struct hypfs_sb_info { + kuid_t uid; /* uid used for files and dirs */ + kgid_t gid; /* gid used for files and dirs */ + struct dentry *update_file; /* file to trigger update */ + time64_t last_update; /* last update, CLOCK_MONOTONIC time */ + struct mutex lock; /* lock to protect update process */ +}; + +static const struct file_operations hypfs_file_ops; +static struct file_system_type hypfs_type; +static const struct super_operations hypfs_s_ops; + +/* start of list of all dentries, which have to be deleted on update */ +static struct dentry *hypfs_last_dentry; + +static void hypfs_update_update(struct super_block *sb) +{ + struct hypfs_sb_info *sb_info = sb->s_fs_info; + struct inode *inode = d_inode(sb_info->update_file); + + sb_info->last_update = ktime_get_seconds(); + inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); +} + +/* directory tree removal functions */ + +static void hypfs_add_dentry(struct dentry *dentry) +{ + dentry->d_fsdata = hypfs_last_dentry; + hypfs_last_dentry = dentry; +} + +static void hypfs_remove(struct dentry *dentry) +{ + struct dentry *parent; + + parent = dentry->d_parent; + inode_lock(d_inode(parent)); + if (simple_positive(dentry)) { + if (d_is_dir(dentry)) + simple_rmdir(d_inode(parent), dentry); + else + simple_unlink(d_inode(parent), dentry); + } + d_drop(dentry); + dput(dentry); + inode_unlock(d_inode(parent)); +} + +static void hypfs_delete_tree(struct dentry *root) +{ + while (hypfs_last_dentry) { + struct dentry *next_dentry; + next_dentry = hypfs_last_dentry->d_fsdata; + hypfs_remove(hypfs_last_dentry); + hypfs_last_dentry = next_dentry; + } +} + +static struct inode *hypfs_make_inode(struct super_block *sb, umode_t mode) +{ + struct inode *ret = new_inode(sb); + + if (ret) { + struct hypfs_sb_info *hypfs_info = sb->s_fs_info; + ret->i_ino = get_next_ino(); + ret->i_mode = mode; + ret->i_uid = hypfs_info->uid; + ret->i_gid = hypfs_info->gid; + ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret); + if (S_ISDIR(mode)) + set_nlink(ret, 2); + } + return ret; +} + +static void hypfs_evict_inode(struct inode *inode) +{ + clear_inode(inode); + kfree(inode->i_private); +} + +static int hypfs_open(struct inode *inode, struct file *filp) +{ + char *data = file_inode(filp)->i_private; + struct hypfs_sb_info *fs_info; + + if (filp->f_mode & FMODE_WRITE) { + if (!(inode->i_mode & S_IWUGO)) + return -EACCES; + } + if (filp->f_mode & FMODE_READ) { + if (!(inode->i_mode & S_IRUGO)) + return -EACCES; + } + + fs_info = inode->i_sb->s_fs_info; + if(data) { + mutex_lock(&fs_info->lock); + filp->private_data = kstrdup(data, GFP_KERNEL); + if (!filp->private_data) { + mutex_unlock(&fs_info->lock); + return -ENOMEM; + } + mutex_unlock(&fs_info->lock); + } + return nonseekable_open(inode, filp); +} + +static ssize_t hypfs_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *file = iocb->ki_filp; + char *data = file->private_data; + size_t available = strlen(data); + loff_t pos = iocb->ki_pos; + size_t count; + + if (pos < 0) + return -EINVAL; + if (pos >= available || !iov_iter_count(to)) + return 0; + count = copy_to_iter(data + pos, available - pos, to); + if (!count) + return -EFAULT; + iocb->ki_pos = pos + count; + file_accessed(file); + return count; +} + +static ssize_t hypfs_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + int rc; + struct super_block *sb = file_inode(iocb->ki_filp)->i_sb; + struct hypfs_sb_info *fs_info = sb->s_fs_info; + size_t count = iov_iter_count(from); + + /* + * Currently we only allow one update per second for two reasons: + * 1. diag 204 is VERY expensive + * 2. If several processes do updates in parallel and then read the + * hypfs data, the likelihood of collisions is reduced, if we restrict + * the minimum update interval. A collision occurs, if during the + * data gathering of one process another process triggers an update + * If the first process wants to ensure consistent data, it has + * to restart data collection in this case. + */ + mutex_lock(&fs_info->lock); + if (fs_info->last_update == ktime_get_seconds()) { + rc = -EBUSY; + goto out; + } + hypfs_delete_tree(sb->s_root); + if (MACHINE_IS_VM) + rc = hypfs_vm_create_files(sb->s_root); + else + rc = hypfs_diag_create_files(sb->s_root); + if (rc) { + pr_err("Updating the hypfs tree failed\n"); + hypfs_delete_tree(sb->s_root); + goto out; + } + hypfs_update_update(sb); + rc = count; + iov_iter_advance(from, count); +out: + mutex_unlock(&fs_info->lock); + return rc; +} + +static int hypfs_release(struct inode *inode, struct file *filp) +{ + kfree(filp->private_data); + return 0; +} + +enum { Opt_uid, Opt_gid, }; + +static const struct fs_parameter_spec hypfs_fs_parameters[] = { + fsparam_u32("gid", Opt_gid), + fsparam_u32("uid", Opt_uid), + {} +}; + +static int hypfs_parse_param(struct fs_context *fc, struct fs_parameter *param) +{ + struct hypfs_sb_info *hypfs_info = fc->s_fs_info; + struct fs_parse_result result; + kuid_t uid; + kgid_t gid; + int opt; + + opt = fs_parse(fc, hypfs_fs_parameters, param, &result); + if (opt < 0) + return opt; + + switch (opt) { + case Opt_uid: + uid = make_kuid(current_user_ns(), result.uint_32); + if (!uid_valid(uid)) + return invalf(fc, "Unknown uid"); + hypfs_info->uid = uid; + break; + case Opt_gid: + gid = make_kgid(current_user_ns(), result.uint_32); + if (!gid_valid(gid)) + return invalf(fc, "Unknown gid"); + hypfs_info->gid = gid; + break; + } + return 0; +} + +static int hypfs_show_options(struct seq_file *s, struct dentry *root) +{ + struct hypfs_sb_info *hypfs_info = root->d_sb->s_fs_info; + + seq_printf(s, ",uid=%u", from_kuid_munged(&init_user_ns, hypfs_info->uid)); + seq_printf(s, ",gid=%u", from_kgid_munged(&init_user_ns, hypfs_info->gid)); + return 0; +} + +static int hypfs_fill_super(struct super_block *sb, struct fs_context *fc) +{ + struct hypfs_sb_info *sbi = sb->s_fs_info; + struct inode *root_inode; + struct dentry *root_dentry, *update_file; + int rc; + + sb->s_blocksize = PAGE_SIZE; + sb->s_blocksize_bits = PAGE_SHIFT; + sb->s_magic = HYPFS_MAGIC; + sb->s_op = &hypfs_s_ops; + + root_inode = hypfs_make_inode(sb, S_IFDIR | 0755); + if (!root_inode) + return -ENOMEM; + root_inode->i_op = &simple_dir_inode_operations; + root_inode->i_fop = &simple_dir_operations; + sb->s_root = root_dentry = d_make_root(root_inode); + if (!root_dentry) + return -ENOMEM; + if (MACHINE_IS_VM) + rc = hypfs_vm_create_files(root_dentry); + else + rc = hypfs_diag_create_files(root_dentry); + if (rc) + return rc; + update_file = hypfs_create_update_file(root_dentry); + if (IS_ERR(update_file)) + return PTR_ERR(update_file); + sbi->update_file = update_file; + hypfs_update_update(sb); + pr_info("Hypervisor filesystem mounted\n"); + return 0; +} + +static int hypfs_get_tree(struct fs_context *fc) +{ + return get_tree_single(fc, hypfs_fill_super); +} + +static void hypfs_free_fc(struct fs_context *fc) +{ + kfree(fc->s_fs_info); +} + +static const struct fs_context_operations hypfs_context_ops = { + .free = hypfs_free_fc, + .parse_param = hypfs_parse_param, + .get_tree = hypfs_get_tree, +}; + +static int hypfs_init_fs_context(struct fs_context *fc) +{ + struct hypfs_sb_info *sbi; + + sbi = kzalloc(sizeof(struct hypfs_sb_info), GFP_KERNEL); + if (!sbi) + return -ENOMEM; + + mutex_init(&sbi->lock); + sbi->uid = current_uid(); + sbi->gid = current_gid(); + + fc->s_fs_info = sbi; + fc->ops = &hypfs_context_ops; + return 0; +} + +static void hypfs_kill_super(struct super_block *sb) +{ + struct hypfs_sb_info *sb_info = sb->s_fs_info; + + if (sb->s_root) + hypfs_delete_tree(sb->s_root); + if (sb_info && sb_info->update_file) + hypfs_remove(sb_info->update_file); + kfree(sb->s_fs_info); + sb->s_fs_info = NULL; + kill_litter_super(sb); +} + +static struct dentry *hypfs_create_file(struct dentry *parent, const char *name, + char *data, umode_t mode) +{ + struct dentry *dentry; + struct inode *inode; + + inode_lock(d_inode(parent)); + dentry = lookup_one_len(name, parent, strlen(name)); + if (IS_ERR(dentry)) { + dentry = ERR_PTR(-ENOMEM); + goto fail; + } + inode = hypfs_make_inode(parent->d_sb, mode); + if (!inode) { + dput(dentry); + dentry = ERR_PTR(-ENOMEM); + goto fail; + } + if (S_ISREG(mode)) { + inode->i_fop = &hypfs_file_ops; + if (data) + inode->i_size = strlen(data); + else + inode->i_size = 0; + } else if (S_ISDIR(mode)) { + inode->i_op = &simple_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + inc_nlink(d_inode(parent)); + } else + BUG(); + inode->i_private = data; + d_instantiate(dentry, inode); + dget(dentry); +fail: + inode_unlock(d_inode(parent)); + return dentry; +} + +struct dentry *hypfs_mkdir(struct dentry *parent, const char *name) +{ + struct dentry *dentry; + + dentry = hypfs_create_file(parent, name, NULL, S_IFDIR | DIR_MODE); + if (IS_ERR(dentry)) + return dentry; + hypfs_add_dentry(dentry); + return dentry; +} + +static struct dentry *hypfs_create_update_file(struct dentry *dir) +{ + struct dentry *dentry; + + dentry = hypfs_create_file(dir, "update", NULL, + S_IFREG | UPDATE_FILE_MODE); + /* + * We do not put the update file on the 'delete' list with + * hypfs_add_dentry(), since it should not be removed when the tree + * is updated. + */ + return dentry; +} + +struct dentry *hypfs_create_u64(struct dentry *dir, + const char *name, __u64 value) +{ + char *buffer; + char tmp[TMP_SIZE]; + struct dentry *dentry; + + snprintf(tmp, TMP_SIZE, "%llu\n", (unsigned long long int)value); + buffer = kstrdup(tmp, GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + dentry = + hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); + if (IS_ERR(dentry)) { + kfree(buffer); + return ERR_PTR(-ENOMEM); + } + hypfs_add_dentry(dentry); + return dentry; +} + +struct dentry *hypfs_create_str(struct dentry *dir, + const char *name, char *string) +{ + char *buffer; + struct dentry *dentry; + + buffer = kmalloc(strlen(string) + 2, GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + sprintf(buffer, "%s\n", string); + dentry = + hypfs_create_file(dir, name, buffer, S_IFREG | REG_FILE_MODE); + if (IS_ERR(dentry)) { + kfree(buffer); + return ERR_PTR(-ENOMEM); + } + hypfs_add_dentry(dentry); + return dentry; +} + +static const struct file_operations hypfs_file_ops = { + .open = hypfs_open, + .release = hypfs_release, + .read_iter = hypfs_read_iter, + .write_iter = hypfs_write_iter, + .llseek = no_llseek, +}; + +static struct file_system_type hypfs_type = { + .owner = THIS_MODULE, + .name = "s390_hypfs", + .init_fs_context = hypfs_init_fs_context, + .parameters = hypfs_fs_parameters, + .kill_sb = hypfs_kill_super +}; + +static const struct super_operations hypfs_s_ops = { + .statfs = simple_statfs, + .evict_inode = hypfs_evict_inode, + .show_options = hypfs_show_options, +}; + +static int __init hypfs_init(void) +{ + int rc; + + hypfs_dbfs_init(); + + if (hypfs_diag_init()) { + rc = -ENODATA; + goto fail_dbfs_exit; + } + if (hypfs_vm_init()) { + rc = -ENODATA; + goto fail_hypfs_diag_exit; + } + hypfs_sprp_init(); + if (hypfs_diag0c_init()) { + rc = -ENODATA; + goto fail_hypfs_sprp_exit; + } + rc = sysfs_create_mount_point(hypervisor_kobj, "s390"); + if (rc) + goto fail_hypfs_diag0c_exit; + rc = register_filesystem(&hypfs_type); + if (rc) + goto fail_filesystem; + return 0; + +fail_filesystem: + sysfs_remove_mount_point(hypervisor_kobj, "s390"); +fail_hypfs_diag0c_exit: + hypfs_diag0c_exit(); +fail_hypfs_sprp_exit: + hypfs_sprp_exit(); + hypfs_vm_exit(); +fail_hypfs_diag_exit: + hypfs_diag_exit(); + pr_err("Initialization of hypfs failed with rc=%i\n", rc); +fail_dbfs_exit: + hypfs_dbfs_exit(); + return rc; +} +device_initcall(hypfs_init) |