From 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 Mon Sep 17 00:00:00 2001 From: Yunhong Jiang Date: Tue, 4 Aug 2015 12:17:53 -0700 Subject: Add the rt linux 4.1.3-rt3 as base Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang --- kernel/fs/filesystems.c | 288 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 288 insertions(+) create mode 100644 kernel/fs/filesystems.c (limited to 'kernel/fs/filesystems.c') diff --git a/kernel/fs/filesystems.c b/kernel/fs/filesystems.c new file mode 100644 index 000000000..5797d45a7 --- /dev/null +++ b/kernel/fs/filesystems.c @@ -0,0 +1,288 @@ +/* + * linux/fs/filesystems.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * table of configured filesystems + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * Handling of filesystem drivers list. + * Rules: + * Inclusion to/removals from/scanning of list are protected by spinlock. + * During the unload module must call unregister_filesystem(). + * We can access the fields of list element if: + * 1) spinlock is held or + * 2) we hold the reference to the module. + * The latter can be guaranteed by call of try_module_get(); if it + * returned 0 we must skip the element, otherwise we got the reference. + * Once the reference is obtained we can drop the spinlock. + */ + +static struct file_system_type *file_systems; +static DEFINE_RWLOCK(file_systems_lock); + +/* WARNING: This can be used only if we _already_ own a reference */ +void get_filesystem(struct file_system_type *fs) +{ + __module_get(fs->owner); +} + +void put_filesystem(struct file_system_type *fs) +{ + module_put(fs->owner); +} + +static struct file_system_type **find_filesystem(const char *name, unsigned len) +{ + struct file_system_type **p; + for (p=&file_systems; *p; p=&(*p)->next) + if (strlen((*p)->name) == len && + strncmp((*p)->name, name, len) == 0) + break; + return p; +} + +/** + * register_filesystem - register a new filesystem + * @fs: the file system structure + * + * Adds the file system passed to the list of file systems the kernel + * is aware of for mount and other syscalls. Returns 0 on success, + * or a negative errno code on an error. + * + * The &struct file_system_type that is passed is linked into the kernel + * structures and must not be freed until the file system has been + * unregistered. + */ + +int register_filesystem(struct file_system_type * fs) +{ + int res = 0; + struct file_system_type ** p; + + BUG_ON(strchr(fs->name, '.')); + if (fs->next) + return -EBUSY; + write_lock(&file_systems_lock); + p = find_filesystem(fs->name, strlen(fs->name)); + if (*p) + res = -EBUSY; + else + *p = fs; + write_unlock(&file_systems_lock); + return res; +} + +EXPORT_SYMBOL(register_filesystem); + +/** + * unregister_filesystem - unregister a file system + * @fs: filesystem to unregister + * + * Remove a file system that was previously successfully registered + * with the kernel. An error is returned if the file system is not found. + * Zero is returned on a success. + * + * Once this function has returned the &struct file_system_type structure + * may be freed or reused. + */ + +int unregister_filesystem(struct file_system_type * fs) +{ + struct file_system_type ** tmp; + + write_lock(&file_systems_lock); + tmp = &file_systems; + while (*tmp) { + if (fs == *tmp) { + *tmp = fs->next; + fs->next = NULL; + write_unlock(&file_systems_lock); + synchronize_rcu(); + return 0; + } + tmp = &(*tmp)->next; + } + write_unlock(&file_systems_lock); + + return -EINVAL; +} + +EXPORT_SYMBOL(unregister_filesystem); + +#ifdef CONFIG_SYSFS_SYSCALL +static int fs_index(const char __user * __name) +{ + struct file_system_type * tmp; + struct filename *name; + int err, index; + + name = getname(__name); + err = PTR_ERR(name); + if (IS_ERR(name)) + return err; + + err = -EINVAL; + read_lock(&file_systems_lock); + for (tmp=file_systems, index=0 ; tmp ; tmp=tmp->next, index++) { + if (strcmp(tmp->name, name->name) == 0) { + err = index; + break; + } + } + read_unlock(&file_systems_lock); + putname(name); + return err; +} + +static int fs_name(unsigned int index, char __user * buf) +{ + struct file_system_type * tmp; + int len, res; + + read_lock(&file_systems_lock); + for (tmp = file_systems; tmp; tmp = tmp->next, index--) + if (index <= 0 && try_module_get(tmp->owner)) + break; + read_unlock(&file_systems_lock); + if (!tmp) + return -EINVAL; + + /* OK, we got the reference, so we can safely block */ + len = strlen(tmp->name) + 1; + res = copy_to_user(buf, tmp->name, len) ? -EFAULT : 0; + put_filesystem(tmp); + return res; +} + +static int fs_maxindex(void) +{ + struct file_system_type * tmp; + int index; + + read_lock(&file_systems_lock); + for (tmp = file_systems, index = 0 ; tmp ; tmp = tmp->next, index++) + ; + read_unlock(&file_systems_lock); + return index; +} + +/* + * Whee.. Weird sysv syscall. + */ +SYSCALL_DEFINE3(sysfs, int, option, unsigned long, arg1, unsigned long, arg2) +{ + int retval = -EINVAL; + + switch (option) { + case 1: + retval = fs_index((const char __user *) arg1); + break; + + case 2: + retval = fs_name(arg1, (char __user *) arg2); + break; + + case 3: + retval = fs_maxindex(); + break; + } + return retval; +} +#endif + +int __init get_filesystem_list(char *buf) +{ + int len = 0; + struct file_system_type * tmp; + + read_lock(&file_systems_lock); + tmp = file_systems; + while (tmp && len < PAGE_SIZE - 80) { + len += sprintf(buf+len, "%s\t%s\n", + (tmp->fs_flags & FS_REQUIRES_DEV) ? "" : "nodev", + tmp->name); + tmp = tmp->next; + } + read_unlock(&file_systems_lock); + return len; +} + +#ifdef CONFIG_PROC_FS +static int filesystems_proc_show(struct seq_file *m, void *v) +{ + struct file_system_type * tmp; + + read_lock(&file_systems_lock); + tmp = file_systems; + while (tmp) { + seq_printf(m, "%s\t%s\n", + (tmp->fs_flags & FS_REQUIRES_DEV) ? "" : "nodev", + tmp->name); + tmp = tmp->next; + } + read_unlock(&file_systems_lock); + return 0; +} + +static int filesystems_proc_open(struct inode *inode, struct file *file) +{ + return single_open(file, filesystems_proc_show, NULL); +} + +static const struct file_operations filesystems_proc_fops = { + .open = filesystems_proc_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static int __init proc_filesystems_init(void) +{ + proc_create("filesystems", 0, NULL, &filesystems_proc_fops); + return 0; +} +module_init(proc_filesystems_init); +#endif + +static struct file_system_type *__get_fs_type(const char *name, int len) +{ + struct file_system_type *fs; + + read_lock(&file_systems_lock); + fs = *(find_filesystem(name, len)); + if (fs && !try_module_get(fs->owner)) + fs = NULL; + read_unlock(&file_systems_lock); + return fs; +} + +struct file_system_type *get_fs_type(const char *name) +{ + struct file_system_type *fs; + const char *dot = strchr(name, '.'); + int len = dot ? dot - name : strlen(name); + + fs = __get_fs_type(name, len); + if (!fs && (request_module("fs-%.*s", len, name) == 0)) + fs = __get_fs_type(name, len); + + if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) { + put_filesystem(fs); + fs = NULL; + } + return fs; +} + +EXPORT_SYMBOL(get_fs_type); -- cgit 1.2.3-korg