--- /dev/null
+/*
+ * fs/hypfs/inode.c
+ * Hypervisor filesystem for Linux on s390.
+ *
+ * Copyright (C) IBM Corp. 2006
+ * Author(s): Michael Holzheu <holzheu@de.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/vfs.h>
+#include <linux/pagemap.h>
+#include <linux/gfp.h>
+#include <linux/time.h>
+#include <linux/parser.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <asm/ebcdic.h>
+#include "hypfs.h"
+#include "hypfs_diag.h"
+
+#define HYPFS_MAGIC 0x687970 /* ASCII 'hyp' */
+#define TMP_SIZE 64 /* size of temporary buffers */
+
+static struct dentry *hypfs_create_update_file(struct super_block *sb,
+ struct dentry *dir);
+
+struct hypfs_sb_info {
+ uid_t uid; /* uid used for files and dirs */
+ gid_t gid; /* gid used for files and dirs */
+ struct dentry *update_file; /* file to trigger update */
+ time_t last_update; /* last update time in secs since 1970 */
+ struct mutex lock; /* lock to protect update process */
+};
+
+static struct file_operations hypfs_file_ops;
+static struct file_system_type hypfs_type;
+static 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 = sb_info->update_file->d_inode;
+
+ sb_info->last_update = get_seconds();
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+}
+
+/* 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;
+ if (S_ISDIR(dentry->d_inode->i_mode))
+ simple_rmdir(parent->d_inode, dentry);
+ else
+ simple_unlink(parent->d_inode, dentry);
+ d_delete(dentry);
+ dput(dentry);
+}
+
+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, int mode)
+{
+ struct inode *ret = new_inode(sb);
+
+ if (ret) {
+ struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
+ ret->i_mode = mode;
+ ret->i_uid = hypfs_info->uid;
+ ret->i_gid = hypfs_info->gid;
+ ret->i_blocks = 0;
+ ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
+ if (mode & S_IFDIR)
+ ret->i_nlink = 2;
+ else
+ ret->i_nlink = 1;
+ }
+ return ret;
+}
+
+static void hypfs_drop_inode(struct inode *inode)
+{
+ kfree(inode->i_private);
+ generic_delete_inode(inode);
+}
+
+static int hypfs_open(struct inode *inode, struct file *filp)
+{
+ char *data = filp->f_dentry->d_inode->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 0;
+}
+
+static ssize_t hypfs_aio_read(struct kiocb *iocb, __user char *buf,
+ size_t count, loff_t offset)
+{
+ char *data;
+ size_t len;
+ struct file *filp = iocb->ki_filp;
+
+ data = filp->private_data;
+ len = strlen(data);
+ if (offset > len) {
+ count = 0;
+ goto out;
+ }
+ if (count > len - offset)
+ count = len - offset;
+ if (copy_to_user(buf, data + offset, count)) {
+ count = -EFAULT;
+ goto out;
+ }
+ iocb->ki_pos += count;
+ file_accessed(filp);
+out:
+ return count;
+}
+static ssize_t hypfs_aio_write(struct kiocb *iocb, const char __user *buf,
+ size_t count, loff_t pos)
+{
+ int rc;
+ struct super_block *sb;
+ struct hypfs_sb_info *fs_info;
+
+ sb = iocb->ki_filp->f_dentry->d_inode->i_sb;
+ fs_info = sb->s_fs_info;
+ /*
+ * 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 == get_seconds()) {
+ rc = -EBUSY;
+ goto out;
+ }
+ hypfs_delete_tree(sb->s_root);
+ rc = hypfs_diag_create_files(sb, sb->s_root);
+ if (rc) {
+ printk(KERN_ERR "hypfs: Update failed\n");
+ hypfs_delete_tree(sb->s_root);
+ goto out;
+ }
+ hypfs_update_update(sb);
+ rc = 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, opt_err };
+
+static match_table_t hypfs_tokens = {
+ {opt_uid, "uid=%u"},
+ {opt_gid, "gid=%u"},
+ {opt_err, NULL}
+};
+
+static int hypfs_parse_options(char *options, struct super_block *sb)
+{
+ char *str;
+ substring_t args[MAX_OPT_ARGS];
+
+ if (!options)
+ return 0;
+ while ((str = strsep(&options, ",")) != NULL) {
+ int token, option;
+ struct hypfs_sb_info *hypfs_info = sb->s_fs_info;
+
+ if (!*str)
+ continue;
+ token = match_token(str, hypfs_tokens, args);
+ switch (token) {
+ case opt_uid:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ hypfs_info->uid = option;
+ break;
+ case opt_gid:
+ if (match_int(&args[0], &option))
+ return -EINVAL;
+ hypfs_info->gid = option;
+ break;
+ case opt_err:
+ default:
+ printk(KERN_ERR "hypfs: Unrecognized mount option "
+ "\"%s\" or missing value\n", str);
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct inode *root_inode;
+ struct dentry *root_dentry;
+ int rc = 0;
+ 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;
+ sb->s_fs_info = sbi;
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = HYPFS_MAGIC;
+ sb->s_op = &hypfs_s_ops;
+ if (hypfs_parse_options(data, sb)) {
+ rc = -EINVAL;
+ goto err_alloc;
+ }
+ root_inode = hypfs_make_inode(sb, S_IFDIR | 0755);
+ if (!root_inode) {
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ root_inode->i_op = &simple_dir_inode_operations;
+ root_inode->i_fop = &simple_dir_operations;
+ root_dentry = d_alloc_root(root_inode);
+ if (!root_dentry) {
+ iput(root_inode);
+ rc = -ENOMEM;
+ goto err_alloc;
+ }
+ rc = hypfs_diag_create_files(sb, root_dentry);
+ if (rc)
+ goto err_tree;
+ sbi->update_file = hypfs_create_update_file(sb, root_dentry);
+ if (IS_ERR(sbi->update_file)) {
+ rc = PTR_ERR(sbi->update_file);
+ goto err_tree;
+ }
+ hypfs_update_update(sb);
+ sb->s_root = root_dentry;
+ return 0;
+
+err_tree:
+ hypfs_delete_tree(root_dentry);
+ d_genocide(root_dentry);
+ dput(root_dentry);
+err_alloc:
+ kfree(sbi);
+ return rc;
+}
+
+static int hypfs_get_super(struct file_system_type *fst, int flags,
+ const char *devname, void *data, struct vfsmount *mnt)
+{
+ return get_sb_single(fst, flags, data, hypfs_fill_super, mnt);
+}
+
+static void hypfs_kill_super(struct super_block *sb)
+{
+ struct hypfs_sb_info *sb_info = sb->s_fs_info;
+
+ hypfs_delete_tree(sb->s_root);
+ 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 super_block *sb,
+ struct dentry *parent, const char *name,
+ char *data, mode_t mode)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+ struct qstr qname;
+
+ qname.name = name;
+ qname.len = strlen(name);
+ qname.hash = full_name_hash(name, qname.len);
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (IS_ERR(dentry))
+ return ERR_PTR(-ENOMEM);
+ inode = hypfs_make_inode(sb, mode);
+ if (!inode) {
+ dput(dentry);
+ return ERR_PTR(-ENOMEM);
+ }
+ if (mode & S_IFREG) {
+ inode->i_fop = &hypfs_file_ops;
+ if (data)
+ inode->i_size = strlen(data);
+ else
+ inode->i_size = 0;
+ } else if (mode & S_IFDIR) {
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+ parent->d_inode->i_nlink++;
+ } else
+ BUG();
+ inode->i_private = data;
+ d_instantiate(dentry, inode);
+ dget(dentry);
+ return dentry;
+}
+
+struct dentry *hypfs_mkdir(struct super_block *sb, struct dentry *parent,
+ const char *name)
+{
+ struct dentry *dentry;
+
+ dentry = hypfs_create_file(sb, parent, name, NULL, S_IFDIR | DIR_MODE);
+ if (IS_ERR(dentry))
+ return dentry;
+ hypfs_add_dentry(dentry);
+ parent->d_inode->i_nlink++;
+ return dentry;
+}
+
+static struct dentry *hypfs_create_update_file(struct super_block *sb,
+ struct dentry *dir)
+{
+ struct dentry *dentry;
+
+ dentry = hypfs_create_file(sb, 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 super_block *sb, struct dentry *dir,
+ const char *name, __u64 value)
+{
+ char *buffer;
+ char tmp[TMP_SIZE];
+ struct dentry *dentry;
+
+ snprintf(tmp, TMP_SIZE, "%lld\n", (unsigned long long int)value);
+ buffer = kstrdup(tmp, GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+ dentry =
+ hypfs_create_file(sb, 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 super_block *sb, 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(sb, 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 struct file_operations hypfs_file_ops = {
+ .open = hypfs_open,
+ .release = hypfs_release,
+ .read = do_sync_read,
+ .write = do_sync_write,
+ .aio_read = hypfs_aio_read,
+ .aio_write = hypfs_aio_write,
+};
+
+static struct file_system_type hypfs_type = {
+ .owner = THIS_MODULE,
+ .name = "s390_hypfs",
+ .get_sb = hypfs_get_super,
+ .kill_sb = hypfs_kill_super
+};
+
+static struct super_operations hypfs_s_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = hypfs_drop_inode,
+};
+
+static decl_subsys(s390, NULL, NULL);
+
+static int __init hypfs_init(void)
+{
+ int rc;
+
+ if (MACHINE_IS_VM)
+ return -ENODATA;
+ if (hypfs_diag_init()) {
+ rc = -ENODATA;
+ goto fail_diag;
+ }
+ kset_set_kset_s(&s390_subsys, hypervisor_subsys);
+ rc = subsystem_register(&s390_subsys);
+ if (rc)
+ goto fail_sysfs;
+ rc = register_filesystem(&hypfs_type);
+ if (rc)
+ goto fail_filesystem;
+ return 0;
+
+fail_filesystem:
+ subsystem_unregister(&s390_subsys);
+fail_sysfs:
+ hypfs_diag_exit();
+fail_diag:
+ printk(KERN_ERR "hypfs: Initialization failed with rc = %i.\n", rc);
+ return rc;
+}
+
+static void __exit hypfs_exit(void)
+{
+ hypfs_diag_exit();
+ unregister_filesystem(&hypfs_type);
+ subsystem_unregister(&s390_subsys);
+}
+
+module_init(hypfs_init)
+module_exit(hypfs_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Holzheu <holzheu@de.ibm.com>");
+MODULE_DESCRIPTION("s390 Hypervisor Filesystem");
git://git.onelab.eu / linux-2.6.git / blobdiff