* table of configured filesystems
*/
+#include <linux/config.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#define __NO_VERSION__
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+/*
+ * 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_inc_mod_count(); 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 rwlock_t file_systems_lock = RW_LOCK_UNLOCKED;
+
+/* WARNING: This can be used only if we _already_ own a reference */
+void get_filesystem(struct file_system_type *fs)
+{
+ if (fs->owner)
+ __MOD_INC_USE_COUNT(fs->owner);
+}
+
+void put_filesystem(struct file_system_type *fs)
+{
+ if (fs->owner)
+ __MOD_DEC_USE_COUNT(fs->owner);
+}
+
+static struct file_system_type **find_filesystem(const char *name)
+{
+ struct file_system_type **p;
+ for (p=&file_systems; *p; p=&(*p)->next)
+ if (strcmp((*p)->name,name) == 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;
+
+ if (!fs)
+ return -EINVAL;
+ if (fs->next)
+ return -EBUSY;
+ INIT_LIST_HEAD(&fs->fs_supers);
+ write_lock(&file_systems_lock);
+ p = find_filesystem(fs->name);
+ if (*p)
+ res = -EBUSY;
+ else
+ *p = fs;
+ write_unlock(&file_systems_lock);
+ return res;
+}
+
+/**
+ * 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);
+ return 0;
+ }
+ tmp = &(*tmp)->next;
+ }
+ write_unlock(&file_systems_lock);
+ return -EINVAL;
+}
+
+static int fs_index(const char * __name)
+{
+ struct file_system_type * tmp;
+ char * 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) == 0) {
+ err = index;
+ break;
+ }
+ }
+ read_unlock(&file_systems_lock);
+ putname(name);
+ return err;
+}
+
+static int fs_name(unsigned int index, char * 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_inc_mod_count(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;
+}
+
/*
- * Code will move here from fs/super.c and yes, it will be fs type handling
- * stuff.
+ * Whee.. Weird sysv syscall.
*/
+asmlinkage long sys_sysfs(int option, unsigned long arg1, unsigned long arg2)
+{
+ int retval = -EINVAL;
+
+ switch (option) {
+ case 1:
+ retval = fs_index((const char *) arg1);
+ break;
+
+ case 2:
+ retval = fs_name(arg1, (char *) arg2);
+ break;
+
+ case 3:
+ retval = fs_maxindex();
+ break;
+ }
+ return retval;
+}
+
+int 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;
+}
+
+struct file_system_type *get_fs_type(const char *name)
+{
+ struct file_system_type *fs;
+
+ read_lock(&file_systems_lock);
+ fs = *(find_filesystem(name));
+ if (fs && !try_inc_mod_count(fs->owner))
+ fs = NULL;
+ read_unlock(&file_systems_lock);
+ if (!fs && (request_module(name) == 0)) {
+ read_lock(&file_systems_lock);
+ fs = *(find_filesystem(name));
+ if (fs && !try_inc_mod_count(fs->owner))
+ fs = NULL;
+ read_unlock(&file_systems_lock);
+ }
+ return fs;
+}
#include <linux/locks.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>
-#include <linux/major.h>
#include <linux/acct.h>
-
#include <asm/uaccess.h>
-#include <linux/kmod.h>
-#define __NO_VERSION__
-#include <linux/module.h>
+void get_filesystem(struct file_system_type *fs);
+void put_filesystem(struct file_system_type *fs);
+struct file_system_type *get_fs_type(const char *name);
LIST_HEAD(super_blocks);
spinlock_t sb_lock = SPIN_LOCK_UNLOCKED;
-/*
- * 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_inc_mod_count(); 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 rwlock_t file_systems_lock = RW_LOCK_UNLOCKED;
-
-/* WARNING: This can be used only if we _already_ own a reference */
-static void get_filesystem(struct file_system_type *fs)
-{
- if (fs->owner)
- __MOD_INC_USE_COUNT(fs->owner);
-}
-
-static void put_filesystem(struct file_system_type *fs)
-{
- if (fs->owner)
- __MOD_DEC_USE_COUNT(fs->owner);
-}
-
-static struct file_system_type **find_filesystem(const char *name)
-{
- struct file_system_type **p;
- for (p=&file_systems; *p; p=&(*p)->next)
- if (strcmp((*p)->name,name) == 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;
-
- if (!fs)
- return -EINVAL;
- if (fs->next)
- return -EBUSY;
- INIT_LIST_HEAD(&fs->fs_supers);
- write_lock(&file_systems_lock);
- p = find_filesystem(fs->name);
- if (*p)
- res = -EBUSY;
- else
- *p = fs;
- write_unlock(&file_systems_lock);
- return res;
-}
-
-/**
- * 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);
- return 0;
- }
- tmp = &(*tmp)->next;
- }
- write_unlock(&file_systems_lock);
- return -EINVAL;
-}
-
-static int fs_index(const char * __name)
-{
- struct file_system_type * tmp;
- char * 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) == 0) {
- err = index;
- break;
- }
- }
- read_unlock(&file_systems_lock);
- putname(name);
- return err;
-}
-
-static int fs_name(unsigned int index, char * 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_inc_mod_count(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.
- */
-asmlinkage long sys_sysfs(int option, unsigned long arg1, unsigned long arg2)
-{
- int retval = -EINVAL;
-
- switch (option) {
- case 1:
- retval = fs_index((const char *) arg1);
- break;
-
- case 2:
- retval = fs_name(arg1, (char *) arg2);
- break;
-
- case 3:
- retval = fs_maxindex();
- break;
- }
- return retval;
-}
-
-int 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;
-}
-
-struct file_system_type *get_fs_type(const char *name)
-{
- struct file_system_type *fs;
-
- read_lock(&file_systems_lock);
- fs = *(find_filesystem(name));
- if (fs && !try_inc_mod_count(fs->owner))
- fs = NULL;
- read_unlock(&file_systems_lock);
- if (!fs && (request_module(name) == 0)) {
- read_lock(&file_systems_lock);
- fs = *(find_filesystem(name));
- if (fs && !try_inc_mod_count(fs->owner))
- fs = NULL;
- read_unlock(&file_systems_lock);
- }
- return fs;
-}
-
/**
* alloc_super - create new superblock
*
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