| /* |
| * linux/fs/super.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * super.c contains code to handle: - mount structures |
| * - super-block tables |
| * - filesystem drivers list |
| * - mount system call |
| * - umount system call |
| * - ustat system call |
| * |
| * GK 2/5/95 - Changed to support mounting the root fs via NFS |
| * |
| * Added kerneld support: Jacques Gelinas and Bjorn Ekwall |
| * Added change_root: Werner Almesberger & Hans Lermen, Feb '96 |
| * Added options to /proc/mounts: |
| * Torbjörn Lindh (torbjorn.lindh@gopta.se), April 14, 1996. |
| * Added devfs support: Richard Gooch <rgooch@atnf.csiro.au>, 13-JAN-1998 |
| * Heavily rewritten for 'one fs - one tree' dcache architecture. AV, Mar 2000 |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/slab.h> |
| #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> |
| |
| 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 |
| * |
| * Allocates and initializes a new &struct super_block. alloc_super() |
| * returns a pointer new superblock or %NULL if allocation had failed. |
| */ |
| static struct super_block *alloc_super(void) |
| { |
| struct super_block *s = kmalloc(sizeof(struct super_block), GFP_USER); |
| if (s) { |
| memset(s, 0, sizeof(struct super_block)); |
| INIT_LIST_HEAD(&s->s_dirty); |
| INIT_LIST_HEAD(&s->s_locked_inodes); |
| INIT_LIST_HEAD(&s->s_files); |
| INIT_LIST_HEAD(&s->s_instances); |
| init_rwsem(&s->s_umount); |
| sema_init(&s->s_lock, 1); |
| down_write(&s->s_umount); |
| s->s_count = S_BIAS; |
| atomic_set(&s->s_active, 1); |
| sema_init(&s->s_vfs_rename_sem,1); |
| sema_init(&s->s_nfsd_free_path_sem,1); |
| sema_init(&s->s_dquot.dqio_sem, 1); |
| sema_init(&s->s_dquot.dqoff_sem, 1); |
| s->s_maxbytes = MAX_NON_LFS; |
| } |
| return s; |
| } |
| |
| /** |
| * destroy_super - frees a superblock |
| * @s: superblock to free |
| * |
| * Frees a superblock. |
| */ |
| static inline void destroy_super(struct super_block *s) |
| { |
| kfree(s); |
| } |
| |
| /* Superblock refcounting */ |
| |
| /** |
| * deactivate_super - turn an active reference into temporary |
| * @s: superblock to deactivate |
| * |
| * Turns an active reference into temporary one. Returns 0 if there are |
| * other active references, 1 if we had deactivated the last one. |
| */ |
| static inline int deactivate_super(struct super_block *s) |
| { |
| if (!atomic_dec_and_lock(&s->s_active, &sb_lock)) |
| return 0; |
| s->s_count -= S_BIAS-1; |
| spin_unlock(&sb_lock); |
| return 1; |
| } |
| |
| /** |
| * put_super - drop a temporary reference to superblock |
| * @s: superblock in question |
| * |
| * Drops a temporary reference, frees superblock if there's no |
| * references left. |
| */ |
| static inline void put_super(struct super_block *s) |
| { |
| spin_lock(&sb_lock); |
| if (!--s->s_count) |
| destroy_super(s); |
| spin_unlock(&sb_lock); |
| } |
| |
| /** |
| * grab_super - acquire an active reference |
| * @s - reference we are trying to make active |
| * |
| * Tries to acquire an active reference. grab_super() is used when we |
| * had just found a superblock in super_blocks or fs_type->fs_supers |
| * and want to turn it into a full-blown active reference. grab_super() |
| * is called with sb_lock held and drops it. Returns 1 in case of |
| * success, 0 if we had failed (superblock contents was already dead or |
| * dying when grab_super() had been called). |
| */ |
| static int grab_super(struct super_block *s) |
| { |
| s->s_count++; |
| spin_unlock(&sb_lock); |
| down_write(&s->s_umount); |
| if (s->s_root) { |
| spin_lock(&sb_lock); |
| if (s->s_count > S_BIAS) { |
| atomic_inc(&s->s_active); |
| s->s_count--; |
| spin_unlock(&sb_lock); |
| return 1; |
| } |
| spin_unlock(&sb_lock); |
| } |
| up_write(&s->s_umount); |
| put_super(s); |
| return 0; |
| } |
| |
| /** |
| * insert_super - put superblock on the lists |
| * @s: superblock in question |
| * @type: filesystem type it will belong to |
| * |
| * Associates superblock with fs type and puts it on per-type and global |
| * superblocks' lists. Should be called with sb_lock held; drops it. |
| */ |
| static void insert_super(struct super_block *s, struct file_system_type *type) |
| { |
| s->s_type = type; |
| list_add(&s->s_list, super_blocks.prev); |
| list_add(&s->s_instances, &type->fs_supers); |
| spin_unlock(&sb_lock); |
| get_filesystem(type); |
| } |
| |
| static void put_anon_dev(kdev_t dev); |
| |
| /** |
| * remove_super - makes superblock unreachable |
| * @s: superblock in question |
| * |
| * Removes superblock from the lists, unlocks it, drop the reference |
| * and releases the hosting device. @s should have no active |
| * references by that time and after remove_super() it's essentially |
| * in rundown mode - all remaining references are temporary, no new |
| * reference of any sort are going to appear and all holders of |
| * temporary ones will eventually drop them. At that point superblock |
| * itself will be destroyed; all its contents is already gone. |
| */ |
| static void remove_super(struct super_block *s) |
| { |
| kdev_t dev = s->s_dev; |
| struct block_device *bdev = s->s_bdev; |
| struct file_system_type *fs = s->s_type; |
| |
| spin_lock(&sb_lock); |
| list_del(&s->s_list); |
| list_del(&s->s_instances); |
| spin_unlock(&sb_lock); |
| up_write(&s->s_umount); |
| put_super(s); |
| put_filesystem(fs); |
| if (bdev) |
| blkdev_put(bdev, BDEV_FS); |
| else |
| put_anon_dev(dev); |
| } |
| |
| struct vfsmount *alloc_vfsmnt(char *name); |
| void free_vfsmnt(struct vfsmount *mnt); |
| |
| static inline struct super_block * find_super(kdev_t dev) |
| { |
| struct list_head *p; |
| |
| list_for_each(p, &super_blocks) { |
| struct super_block * s = sb_entry(p); |
| if (kdev_same(s->s_dev, dev)) { |
| s->s_count++; |
| return s; |
| } |
| } |
| return NULL; |
| } |
| |
| void drop_super(struct super_block *sb) |
| { |
| up_read(&sb->s_umount); |
| put_super(sb); |
| } |
| |
| static inline void write_super(struct super_block *sb) |
| { |
| lock_super(sb); |
| if (sb->s_root && sb->s_dirt) |
| if (sb->s_op && sb->s_op->write_super) |
| sb->s_op->write_super(sb); |
| unlock_super(sb); |
| } |
| |
| /* |
| * Note: check the dirty flag before waiting, so we don't |
| * hold up the sync while mounting a device. (The newly |
| * mounted device won't need syncing.) |
| */ |
| void sync_supers(kdev_t dev) |
| { |
| struct super_block * sb; |
| |
| if (!kdev_none(dev)) { |
| sb = get_super(dev); |
| if (sb) { |
| if (sb->s_dirt) |
| write_super(sb); |
| drop_super(sb); |
| } |
| return; |
| } |
| restart: |
| spin_lock(&sb_lock); |
| sb = sb_entry(super_blocks.next); |
| while (sb != sb_entry(&super_blocks)) |
| if (sb->s_dirt) { |
| sb->s_count++; |
| spin_unlock(&sb_lock); |
| down_read(&sb->s_umount); |
| write_super(sb); |
| drop_super(sb); |
| goto restart; |
| } else |
| sb = sb_entry(sb->s_list.next); |
| spin_unlock(&sb_lock); |
| } |
| |
| /** |
| * get_super - get the superblock of a device |
| * @dev: device to get the superblock for |
| * |
| * Scans the superblock list and finds the superblock of the file system |
| * mounted on the device given. %NULL is returned if no match is found. |
| */ |
| |
| struct super_block * get_super(kdev_t dev) |
| { |
| struct super_block * s; |
| |
| if (kdev_none(dev)) |
| return NULL; |
| |
| while (1) { |
| spin_lock(&sb_lock); |
| s = find_super(dev); |
| spin_unlock(&sb_lock); |
| if (!s) |
| break; |
| down_read(&s->s_umount); |
| if (s->s_root) |
| break; |
| drop_super(s); |
| } |
| return s; |
| } |
| |
| asmlinkage long sys_ustat(dev_t dev, struct ustat * ubuf) |
| { |
| struct super_block *s; |
| struct ustat tmp; |
| struct statfs sbuf; |
| int err = -EINVAL; |
| |
| s = get_super(to_kdev_t(dev)); |
| if (s == NULL) |
| goto out; |
| err = vfs_statfs(s, &sbuf); |
| drop_super(s); |
| if (err) |
| goto out; |
| |
| memset(&tmp,0,sizeof(struct ustat)); |
| tmp.f_tfree = sbuf.f_bfree; |
| tmp.f_tinode = sbuf.f_ffree; |
| |
| err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0; |
| out: |
| return err; |
| } |
| |
| /** |
| * do_remount_sb - asks filesystem to change mount options. |
| * @sb: superblock in question |
| * @flags: numeric part of options |
| * @data: the rest of options |
| * |
| * Alters the mount options of a mounted file system. |
| */ |
| int do_remount_sb(struct super_block *sb, int flags, void *data) |
| { |
| int retval; |
| |
| if (!(flags & MS_RDONLY) && !kdev_none(sb->s_dev) && is_read_only(sb->s_dev)) |
| return -EACCES; |
| /*flags |= MS_RDONLY;*/ |
| if (flags & MS_RDONLY) |
| acct_auto_close(sb); |
| shrink_dcache_sb(sb); |
| fsync_super(sb); |
| /* If we are remounting RDONLY, make sure there are no rw files open */ |
| if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) |
| if (!fs_may_remount_ro(sb)) |
| return -EBUSY; |
| if (sb->s_op && sb->s_op->remount_fs) { |
| lock_super(sb); |
| retval = sb->s_op->remount_fs(sb, &flags, data); |
| unlock_super(sb); |
| if (retval) |
| return retval; |
| } |
| sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK); |
| return 0; |
| } |
| |
| /* |
| * Unnamed block devices are dummy devices used by virtual |
| * filesystems which don't use real block-devices. -- jrs |
| */ |
| |
| enum {Max_anon = 256}; |
| static unsigned long unnamed_dev_in_use[Max_anon/(8*sizeof(unsigned long))]; |
| static spinlock_t unnamed_dev_lock = SPIN_LOCK_UNLOCKED;/* protects the above */ |
| |
| /** |
| * put_anon_dev - release anonymous device number. |
| * @dev: device in question |
| */ |
| static void put_anon_dev(kdev_t dev) |
| { |
| spin_lock(&unnamed_dev_lock); |
| clear_bit(minor(dev), unnamed_dev_in_use); |
| spin_unlock(&unnamed_dev_lock); |
| } |
| |
| /** |
| * get_anon_super - allocate a superblock for non-device fs |
| * @type: filesystem type |
| * @compare: check if existing superblock is what we want |
| * @data: argument for @compare. |
| * |
| * get_anon_super is a helper for non-blockdevice filesystems. |
| * It either finds and returns one of the superblocks of given type |
| * (if it can find one that would satisfy caller) or creates a new |
| * one. In the either case we return an active reference to superblock |
| * with ->s_umount locked. If superblock is new it gets a new |
| * anonymous device allocated for it and is inserted into lists - |
| * other initialization is left to caller. |
| * |
| * Rather than duplicating all that logics every time when |
| * we want something that doesn't fit "nodev" and "single" we pull |
| * the relevant code into common helper and let get_sb_...() call |
| * it. |
| * |
| * NB: get_sb_...() is going to become an fs type method, with |
| * current ->read_super() becoming a callback used by common instances. |
| */ |
| struct super_block *get_anon_super(struct file_system_type *type, |
| int (*compare)(struct super_block *,void *), void *data) |
| { |
| struct super_block *s = alloc_super(); |
| int dev; |
| struct list_head *p; |
| |
| if (!s) |
| return ERR_PTR(-ENOMEM); |
| |
| spin_lock(&unnamed_dev_lock); |
| dev = find_first_zero_bit(unnamed_dev_in_use, Max_anon); |
| if (dev == Max_anon) { |
| spin_unlock(&unnamed_dev_lock); |
| destroy_super(s); |
| return ERR_PTR(-EMFILE); |
| } |
| set_bit(dev, unnamed_dev_in_use); |
| spin_unlock(&unnamed_dev_lock); |
| |
| retry: |
| spin_lock(&sb_lock); |
| if (compare) list_for_each(p, &type->fs_supers) { |
| struct super_block *old; |
| old = list_entry(p, struct super_block, s_instances); |
| if (!compare(old, data)) |
| continue; |
| if (!grab_super(old)) |
| goto retry; |
| destroy_super(s); |
| return old; |
| } |
| |
| s->s_dev = mk_kdev(0, dev); |
| insert_super(s, type); |
| return s; |
| } |
| |
| struct super_block *get_sb_bdev(struct file_system_type *fs_type, |
| int flags, char *dev_name, void * data, |
| int (*fill_super)(struct super_block *, void *, int)) |
| { |
| struct inode *inode; |
| struct block_device *bdev; |
| struct block_device_operations *bdops; |
| devfs_handle_t de; |
| struct super_block * s; |
| struct nameidata nd; |
| struct list_head *p; |
| kdev_t dev; |
| int error = 0; |
| mode_t mode = FMODE_READ; /* we always need it ;-) */ |
| |
| /* What device it is? */ |
| if (!dev_name || !*dev_name) |
| return ERR_PTR(-EINVAL); |
| if (path_init(dev_name, LOOKUP_FOLLOW|LOOKUP_POSITIVE, &nd)) |
| error = path_walk(dev_name, &nd); |
| if (error) |
| return ERR_PTR(error); |
| inode = nd.dentry->d_inode; |
| error = -ENOTBLK; |
| if (!S_ISBLK(inode->i_mode)) |
| goto out; |
| error = -EACCES; |
| if (nd.mnt->mnt_flags & MNT_NODEV) |
| goto out; |
| bd_acquire(inode); |
| bdev = inode->i_bdev; |
| de = devfs_get_handle_from_inode (inode); |
| bdops = devfs_get_ops (de); /* Increments module use count */ |
| if (bdops) bdev->bd_op = bdops; |
| /* Done with lookups, semaphore down */ |
| dev = to_kdev_t(bdev->bd_dev); |
| if (!(flags & MS_RDONLY)) |
| mode |= FMODE_WRITE; |
| error = blkdev_get(bdev, mode, 0, BDEV_FS); |
| devfs_put_ops (de); /* Decrement module use count now we're safe */ |
| if (error) |
| goto out; |
| check_disk_change(dev); |
| error = -EACCES; |
| if (!(flags & MS_RDONLY) && is_read_only(dev)) |
| goto out1; |
| |
| error = -ENOMEM; |
| s = alloc_super(); |
| if (!s) |
| goto out1; |
| |
| error = -EBUSY; |
| restart: |
| spin_lock(&sb_lock); |
| |
| list_for_each(p, &super_blocks) { |
| struct super_block *old = sb_entry(p); |
| if (old->s_bdev != bdev) |
| continue; |
| if (old->s_type != fs_type || |
| ((flags ^ old->s_flags) & MS_RDONLY)) { |
| spin_unlock(&sb_lock); |
| destroy_super(s); |
| goto out1; |
| } |
| if (!grab_super(old)) |
| goto restart; |
| destroy_super(s); |
| blkdev_put(bdev, BDEV_FS); |
| path_release(&nd); |
| return old; |
| } |
| s->s_dev = dev; |
| s->s_bdev = bdev; |
| s->s_flags = flags; |
| insert_super(s, fs_type); |
| strncpy(s->s_id, bdevname(dev), sizeof(s->s_id)); |
| error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
| if (error) |
| goto failed; |
| s->s_flags |= MS_ACTIVE; |
| path_release(&nd); |
| return s; |
| |
| failed: |
| deactivate_super(s); |
| remove_super(s); |
| goto out; |
| out1: |
| blkdev_put(bdev, BDEV_FS); |
| out: |
| path_release(&nd); |
| return ERR_PTR(error); |
| } |
| |
| struct super_block *get_sb_nodev(struct file_system_type *fs_type, |
| int flags, void *data, |
| int (*fill_super)(struct super_block *, void *, int)) |
| { |
| int error; |
| struct super_block *s = get_anon_super(fs_type, NULL, NULL); |
| |
| if (IS_ERR(s)) |
| return s; |
| |
| s->s_flags = flags; |
| |
| error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
| if (error) { |
| deactivate_super(s); |
| remove_super(s); |
| return ERR_PTR(error); |
| } |
| s->s_flags |= MS_ACTIVE; |
| return s; |
| } |
| |
| static int compare_single(struct super_block *s, void *p) |
| { |
| return 1; |
| } |
| |
| struct super_block *get_sb_single(struct file_system_type *fs_type, |
| int flags, void *data, |
| int (*fill_super)(struct super_block *, void *, int)) |
| { |
| int error; |
| struct super_block *s = get_anon_super(fs_type, compare_single, NULL); |
| |
| if (IS_ERR(s)) |
| return s; |
| if (!s->s_root) { |
| s->s_flags = flags; |
| error = fill_super(s, data, flags & MS_VERBOSE ? 1 : 0); |
| if (error) { |
| deactivate_super(s); |
| remove_super(s); |
| return ERR_PTR(error); |
| } |
| s->s_flags |= MS_ACTIVE; |
| } |
| do_remount_sb(s, flags, data); |
| return s; |
| } |
| |
| /* Will go away */ |
| static int fill_super(struct super_block *sb, void *data, int verbose) |
| { |
| return sb->s_type->read_super(sb, data, verbose) ? 0 : -EINVAL; |
| } |
| static struct super_block *__get_sb_bdev(struct file_system_type *fs_type, |
| int flags, char *dev_name, void * data) |
| { |
| return get_sb_bdev(fs_type, flags, dev_name, data, fill_super); |
| } |
| |
| struct vfsmount * |
| do_kern_mount(const char *fstype, int flags, char *name, void *data) |
| { |
| struct file_system_type *type = get_fs_type(fstype); |
| struct super_block *sb = ERR_PTR(-ENOMEM); |
| struct vfsmount *mnt; |
| |
| if (!type) |
| return ERR_PTR(-ENODEV); |
| |
| mnt = alloc_vfsmnt(name); |
| if (!mnt) |
| goto out; |
| if (type->get_sb) |
| sb = type->get_sb(type, flags, name, data); |
| else if (type->fs_flags & FS_REQUIRES_DEV) |
| sb = __get_sb_bdev(type, flags, name, data); |
| if (IS_ERR(sb)) |
| goto out_mnt; |
| if (type->fs_flags & FS_NOMOUNT) |
| sb->s_flags |= MS_NOUSER; |
| mnt->mnt_sb = sb; |
| mnt->mnt_root = dget(sb->s_root); |
| mnt->mnt_mountpoint = sb->s_root; |
| mnt->mnt_parent = mnt; |
| up_write(&sb->s_umount); |
| put_filesystem(type); |
| return mnt; |
| out_mnt: |
| free_vfsmnt(mnt); |
| out: |
| put_filesystem(type); |
| return (struct vfsmount *)sb; |
| } |
| |
| void kill_super(struct super_block *sb) |
| { |
| struct dentry *root = sb->s_root; |
| struct file_system_type *fs = sb->s_type; |
| struct super_operations *sop = sb->s_op; |
| |
| if (!deactivate_super(sb)) |
| return; |
| |
| down_write(&sb->s_umount); |
| sb->s_root = NULL; |
| /* Need to clean after the sucker */ |
| if (fs->fs_flags & FS_LITTER) |
| d_genocide(root); |
| shrink_dcache_parent(root); |
| dput(root); |
| fsync_super(sb); |
| lock_super(sb); |
| lock_kernel(); |
| sb->s_flags &= ~MS_ACTIVE; |
| invalidate_inodes(sb); /* bad name - it should be evict_inodes() */ |
| if (sop) { |
| if (sop->write_super && sb->s_dirt) |
| sop->write_super(sb); |
| if (sop->put_super) |
| sop->put_super(sb); |
| } |
| |
| /* Forget any remaining inodes */ |
| if (invalidate_inodes(sb)) { |
| printk("VFS: Busy inodes after unmount. " |
| "Self-destruct in 5 seconds. Have a nice day...\n"); |
| } |
| |
| unlock_kernel(); |
| unlock_super(sb); |
| remove_super(sb); |
| } |
| |
| struct vfsmount *kern_mount(struct file_system_type *type) |
| { |
| return do_kern_mount(type->name, 0, (char *)type->name, NULL); |
| } |