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- #include <linux/export.h>
- #include <linux/slab.h>
- #include <linux/blkdev.h>
- #include <linux/mount.h>
- #include <linux/security.h>
- #include <linux/writeback.h> /* for the emergency remount stuff */
- #include <linux/idr.h>
- #include <linux/mutex.h>
- #include <linux/backing-dev.h>
- #include <linux/rculist_bl.h>
- #include <linux/cleancache.h>
- #include <linux/fsnotify.h>
- #include <linux/lockdep.h>
- #include <linux/user_namespace.h>
- #include "internal.h"
- static LIST_HEAD(super_blocks);
- static DEFINE_SPINLOCK(sb_lock);
- static char *sb_writers_name[SB_FREEZE_LEVELS] = {
- "sb_writers",
- "sb_pagefaults",
- "sb_internal",
- };
- static unsigned long super_cache_scan(struct shrinker *shrink,
- struct shrink_control *sc)
- {
- struct super_block *sb;
- long fs_objects = 0;
- long total_objects;
- long freed = 0;
- long dentries;
- long inodes;
- sb = container_of(shrink, struct super_block, s_shrink);
-
- if (!(sc->gfp_mask & __GFP_FS))
- return SHRINK_STOP;
- if (!trylock_super(sb))
- return SHRINK_STOP;
- if (sb->s_op->nr_cached_objects)
- fs_objects = sb->s_op->nr_cached_objects(sb, sc);
- inodes = list_lru_shrink_count(&sb->s_inode_lru, sc);
- dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc);
- total_objects = dentries + inodes + fs_objects + 1;
- if (!total_objects)
- total_objects = 1;
-
- dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
- inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
- fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects);
-
- sc->nr_to_scan = dentries + 1;
- freed = prune_dcache_sb(sb, sc);
- sc->nr_to_scan = inodes + 1;
- freed += prune_icache_sb(sb, sc);
- if (fs_objects) {
- sc->nr_to_scan = fs_objects + 1;
- freed += sb->s_op->free_cached_objects(sb, sc);
- }
- up_read(&sb->s_umount);
- return freed;
- }
- static unsigned long super_cache_count(struct shrinker *shrink,
- struct shrink_control *sc)
- {
- struct super_block *sb;
- long total_objects = 0;
- sb = container_of(shrink, struct super_block, s_shrink);
-
- if (!(sb->s_flags & MS_BORN))
- return 0;
- smp_rmb();
- if (sb->s_op && sb->s_op->nr_cached_objects)
- total_objects = sb->s_op->nr_cached_objects(sb, sc);
- total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc);
- total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc);
- total_objects = vfs_pressure_ratio(total_objects);
- return total_objects;
- }
- static void destroy_super_work(struct work_struct *work)
- {
- struct super_block *s = container_of(work, struct super_block,
- destroy_work);
- int i;
- for (i = 0; i < SB_FREEZE_LEVELS; i++)
- percpu_free_rwsem(&s->s_writers.rw_sem[i]);
- kfree(s);
- }
- static void destroy_super_rcu(struct rcu_head *head)
- {
- struct super_block *s = container_of(head, struct super_block, rcu);
- INIT_WORK(&s->destroy_work, destroy_super_work);
- schedule_work(&s->destroy_work);
- }
- static void destroy_super(struct super_block *s)
- {
- list_lru_destroy(&s->s_dentry_lru);
- list_lru_destroy(&s->s_inode_lru);
- security_sb_free(s);
- WARN_ON(!list_empty(&s->s_mounts));
- put_user_ns(s->s_user_ns);
- kfree(s->s_subtype);
- kfree(s->s_options);
- call_rcu(&s->rcu, destroy_super_rcu);
- }
- static struct super_block *alloc_super(struct file_system_type *type, int flags,
- struct user_namespace *user_ns)
- {
- struct super_block *s = kzalloc(sizeof(struct super_block), GFP_USER);
- static const struct super_operations default_op;
- int i;
- if (!s)
- return NULL;
- INIT_LIST_HEAD(&s->s_mounts);
- s->s_user_ns = get_user_ns(user_ns);
- if (security_sb_alloc(s))
- goto fail;
- for (i = 0; i < SB_FREEZE_LEVELS; i++) {
- if (__percpu_init_rwsem(&s->s_writers.rw_sem[i],
- sb_writers_name[i],
- &type->s_writers_key[i]))
- goto fail;
- }
- init_waitqueue_head(&s->s_writers.wait_unfrozen);
- s->s_bdi = &noop_backing_dev_info;
- s->s_flags = flags;
- if (s->s_user_ns != &init_user_ns)
- s->s_iflags |= SB_I_NODEV;
- INIT_HLIST_NODE(&s->s_instances);
- INIT_HLIST_BL_HEAD(&s->s_anon);
- mutex_init(&s->s_sync_lock);
- INIT_LIST_HEAD(&s->s_inodes);
- spin_lock_init(&s->s_inode_list_lock);
- INIT_LIST_HEAD(&s->s_inodes_wb);
- spin_lock_init(&s->s_inode_wblist_lock);
- #if IS_ENABLED(CONFIG_FS_VERITY)
-
- INIT_LIST_HEAD(&s->s_inodes_fsverity);
- spin_lock_init(&s->s_inode_fsveritylist_lock);
- #endif
- if (list_lru_init_memcg(&s->s_dentry_lru))
- goto fail;
- if (list_lru_init_memcg(&s->s_inode_lru))
- goto fail;
- init_rwsem(&s->s_umount);
- lockdep_set_class(&s->s_umount, &type->s_umount_key);
-
- down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING);
- s->s_count = 1;
- atomic_set(&s->s_active, 1);
- mutex_init(&s->s_vfs_rename_mutex);
- lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
- mutex_init(&s->s_dquot.dqio_mutex);
- mutex_init(&s->s_dquot.dqonoff_mutex);
- s->s_maxbytes = MAX_NON_LFS;
- s->s_op = &default_op;
- s->s_time_gran = 1000000000;
- s->cleancache_poolid = CLEANCACHE_NO_POOL;
- s->s_shrink.seeks = DEFAULT_SEEKS;
- s->s_shrink.scan_objects = super_cache_scan;
- s->s_shrink.count_objects = super_cache_count;
- s->s_shrink.batch = 1024;
- s->s_shrink.flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE;
- return s;
- fail:
- destroy_super(s);
- return NULL;
- }
- static void __put_super(struct super_block *sb)
- {
- if (!--sb->s_count) {
- list_del_init(&sb->s_list);
- destroy_super(sb);
- }
- }
- static void put_super(struct super_block *sb)
- {
- spin_lock(&sb_lock);
- __put_super(sb);
- spin_unlock(&sb_lock);
- }
- void deactivate_locked_super(struct super_block *s)
- {
- struct file_system_type *fs = s->s_type;
- if (atomic_dec_and_test(&s->s_active)) {
- cleancache_invalidate_fs(s);
- unregister_shrinker(&s->s_shrink);
- fs->kill_sb(s);
-
- list_lru_destroy(&s->s_dentry_lru);
- list_lru_destroy(&s->s_inode_lru);
- put_filesystem(fs);
- put_super(s);
- } else {
- up_write(&s->s_umount);
- }
- }
- EXPORT_SYMBOL(deactivate_locked_super);
- void deactivate_super(struct super_block *s)
- {
- if (!atomic_add_unless(&s->s_active, -1, 1)) {
- down_write(&s->s_umount);
- deactivate_locked_super(s);
- }
- }
- EXPORT_SYMBOL(deactivate_super);
- static int grab_super(struct super_block *s) __releases(sb_lock)
- {
- s->s_count++;
- spin_unlock(&sb_lock);
- down_write(&s->s_umount);
- if ((s->s_flags & MS_BORN) && atomic_inc_not_zero(&s->s_active)) {
- put_super(s);
- return 1;
- }
- up_write(&s->s_umount);
- put_super(s);
- return 0;
- }
- bool trylock_super(struct super_block *sb)
- {
- if (down_read_trylock(&sb->s_umount)) {
- if (!hlist_unhashed(&sb->s_instances) &&
- sb->s_root && (sb->s_flags & MS_BORN))
- return true;
- up_read(&sb->s_umount);
- }
- return false;
- }
- #if IS_ENABLED(CONFIG_FS_VERITY)
- static void fsverity_unmount_inodes(struct super_block *sb)
- {
- struct inode *inode, *tmp;
-
- list_for_each_entry_safe(inode, tmp, &sb->s_inodes_fsverity,
- i_fsverity_list) {
- list_del_init(&inode->i_fsverity_list);
- iput(inode);
- }
- }
- #else
- static inline void fsverity_unmount_inodes(struct super_block *sb)
- {
- }
- #endif
- void generic_shutdown_super(struct super_block *sb)
- {
- const struct super_operations *sop = sb->s_op;
- if (sb->s_root) {
- shrink_dcache_for_umount(sb);
- sync_filesystem(sb);
- sb->s_flags &= ~MS_ACTIVE;
- fsnotify_unmount_inodes(sb);
- cgroup_writeback_umount();
- fsverity_unmount_inodes(sb);
- evict_inodes(sb);
- if (sb->s_dio_done_wq) {
- destroy_workqueue(sb->s_dio_done_wq);
- sb->s_dio_done_wq = NULL;
- }
- if (sop->put_super)
- sop->put_super(sb);
- if (!list_empty(&sb->s_inodes)) {
- printk("VFS: Busy inodes after unmount of %s. "
- "Self-destruct in 5 seconds. Have a nice day...\n",
- sb->s_id);
- }
- }
- spin_lock(&sb_lock);
-
- hlist_del_init(&sb->s_instances);
- spin_unlock(&sb_lock);
- up_write(&sb->s_umount);
- }
- EXPORT_SYMBOL(generic_shutdown_super);
- struct super_block *sget_userns(struct file_system_type *type,
- int (*test)(struct super_block *,void *),
- int (*set)(struct super_block *,void *),
- int flags, struct user_namespace *user_ns,
- void *data)
- {
- struct super_block *s = NULL;
- struct super_block *old;
- int err;
- if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) &&
- !(type->fs_flags & FS_USERNS_MOUNT) &&
- !capable(CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
- retry:
- spin_lock(&sb_lock);
- if (test) {
- hlist_for_each_entry(old, &type->fs_supers, s_instances) {
- if (!test(old, data))
- continue;
- if (user_ns != old->s_user_ns) {
- spin_unlock(&sb_lock);
- if (s) {
- up_write(&s->s_umount);
- destroy_super(s);
- }
- return ERR_PTR(-EBUSY);
- }
- if (!grab_super(old))
- goto retry;
- if (s) {
- up_write(&s->s_umount);
- destroy_super(s);
- s = NULL;
- }
- return old;
- }
- }
- if (!s) {
- spin_unlock(&sb_lock);
- s = alloc_super(type, (flags & ~MS_SUBMOUNT), user_ns);
- if (!s)
- return ERR_PTR(-ENOMEM);
- goto retry;
- }
-
- err = set(s, data);
- if (err) {
- spin_unlock(&sb_lock);
- up_write(&s->s_umount);
- destroy_super(s);
- return ERR_PTR(err);
- }
- s->s_type = type;
- strlcpy(s->s_id, type->name, sizeof(s->s_id));
- list_add_tail(&s->s_list, &super_blocks);
- hlist_add_head(&s->s_instances, &type->fs_supers);
- spin_unlock(&sb_lock);
- get_filesystem(type);
- err = register_shrinker(&s->s_shrink);
- if (err) {
- deactivate_locked_super(s);
- s = ERR_PTR(err);
- }
- return s;
- }
- EXPORT_SYMBOL(sget_userns);
- struct super_block *sget(struct file_system_type *type,
- int (*test)(struct super_block *,void *),
- int (*set)(struct super_block *,void *),
- int flags,
- void *data)
- {
- struct user_namespace *user_ns = current_user_ns();
-
- if (flags & MS_SUBMOUNT)
- user_ns = &init_user_ns;
-
- if (!(flags & (MS_KERNMOUNT|MS_SUBMOUNT)) && !ns_capable(user_ns, CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
- return sget_userns(type, test, set, flags, user_ns, data);
- }
- EXPORT_SYMBOL(sget);
- void drop_super(struct super_block *sb)
- {
- up_read(&sb->s_umount);
- put_super(sb);
- }
- EXPORT_SYMBOL(drop_super);
- void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
- {
- struct super_block *sb, *p = NULL;
- spin_lock(&sb_lock);
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (hlist_unhashed(&sb->s_instances))
- continue;
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- if (sb->s_root && (sb->s_flags & MS_BORN))
- f(sb, arg);
- up_read(&sb->s_umount);
- spin_lock(&sb_lock);
- if (p)
- __put_super(p);
- p = sb;
- }
- if (p)
- __put_super(p);
- spin_unlock(&sb_lock);
- }
- void iterate_supers_type(struct file_system_type *type,
- void (*f)(struct super_block *, void *), void *arg)
- {
- struct super_block *sb, *p = NULL;
- spin_lock(&sb_lock);
- hlist_for_each_entry(sb, &type->fs_supers, s_instances) {
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- if (sb->s_root && (sb->s_flags & MS_BORN))
- f(sb, arg);
- up_read(&sb->s_umount);
- spin_lock(&sb_lock);
- if (p)
- __put_super(p);
- p = sb;
- }
- if (p)
- __put_super(p);
- spin_unlock(&sb_lock);
- }
- EXPORT_SYMBOL(iterate_supers_type);
- struct super_block *get_super(struct block_device *bdev)
- {
- struct super_block *sb;
- if (!bdev)
- return NULL;
- spin_lock(&sb_lock);
- rescan:
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (hlist_unhashed(&sb->s_instances))
- continue;
- if (sb->s_bdev == bdev) {
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
-
- if (sb->s_root && (sb->s_flags & MS_BORN))
- return sb;
- up_read(&sb->s_umount);
-
- spin_lock(&sb_lock);
- __put_super(sb);
- goto rescan;
- }
- }
- spin_unlock(&sb_lock);
- return NULL;
- }
- EXPORT_SYMBOL(get_super);
- struct super_block *get_super_thawed(struct block_device *bdev)
- {
- while (1) {
- struct super_block *s = get_super(bdev);
- if (!s || s->s_writers.frozen == SB_UNFROZEN)
- return s;
- up_read(&s->s_umount);
- wait_event(s->s_writers.wait_unfrozen,
- s->s_writers.frozen == SB_UNFROZEN);
- put_super(s);
- }
- }
- EXPORT_SYMBOL(get_super_thawed);
- struct super_block *get_active_super(struct block_device *bdev)
- {
- struct super_block *sb;
- if (!bdev)
- return NULL;
- restart:
- spin_lock(&sb_lock);
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (hlist_unhashed(&sb->s_instances))
- continue;
- if (sb->s_bdev == bdev) {
- if (!grab_super(sb))
- goto restart;
- up_write(&sb->s_umount);
- return sb;
- }
- }
- spin_unlock(&sb_lock);
- return NULL;
- }
-
- struct super_block *user_get_super(dev_t dev)
- {
- struct super_block *sb;
- spin_lock(&sb_lock);
- rescan:
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (hlist_unhashed(&sb->s_instances))
- continue;
- if (sb->s_dev == dev) {
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
-
- if (sb->s_root && (sb->s_flags & MS_BORN))
- return sb;
- up_read(&sb->s_umount);
-
- spin_lock(&sb_lock);
- __put_super(sb);
- goto rescan;
- }
- }
- spin_unlock(&sb_lock);
- return NULL;
- }
- int do_remount_sb2(struct vfsmount *mnt, struct super_block *sb, int flags, void *data, int force)
- {
- int retval;
- int remount_ro;
- if (sb->s_writers.frozen != SB_UNFROZEN)
- return -EBUSY;
- #ifdef CONFIG_BLOCK
- if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
- return -EACCES;
- #endif
- remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
- if (remount_ro) {
- if (!hlist_empty(&sb->s_pins)) {
- up_write(&sb->s_umount);
- group_pin_kill(&sb->s_pins);
- down_write(&sb->s_umount);
- if (!sb->s_root)
- return 0;
- if (sb->s_writers.frozen != SB_UNFROZEN)
- return -EBUSY;
- remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
- }
- }
- shrink_dcache_sb(sb);
-
- if (remount_ro) {
- if (force) {
- sb->s_readonly_remount = 1;
- smp_wmb();
- } else {
- retval = sb_prepare_remount_readonly(sb);
- if (retval)
- return retval;
- }
- }
- if (mnt && sb->s_op->remount_fs2) {
- retval = sb->s_op->remount_fs2(mnt, sb, &flags, data);
- if (retval) {
- if (!force)
- goto cancel_readonly;
-
- WARN(1, "forced remount of a %s fs returned %i\n",
- sb->s_type->name, retval);
- }
- } else if (sb->s_op->remount_fs) {
- retval = sb->s_op->remount_fs(sb, &flags, data);
- if (retval) {
- if (!force)
- goto cancel_readonly;
-
- WARN(1, "forced remount of a %s fs returned %i\n",
- sb->s_type->name, retval);
- }
- }
- sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
-
- smp_wmb();
- sb->s_readonly_remount = 0;
-
- if (remount_ro && sb->s_bdev)
- invalidate_bdev(sb->s_bdev);
- return 0;
- cancel_readonly:
- sb->s_readonly_remount = 0;
- return retval;
- }
- int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
- {
- return do_remount_sb2(NULL, sb, flags, data, force);
- }
- static void do_emergency_remount(struct work_struct *work)
- {
- struct super_block *sb, *p = NULL;
- spin_lock(&sb_lock);
- list_for_each_entry_reverse(sb, &super_blocks, s_list) {
- if (hlist_unhashed(&sb->s_instances))
- continue;
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_write(&sb->s_umount);
- if (sb->s_root && sb->s_bdev && (sb->s_flags & MS_BORN) &&
- !(sb->s_flags & MS_RDONLY)) {
-
- do_remount_sb(sb, MS_RDONLY, NULL, 1);
- }
- up_write(&sb->s_umount);
- spin_lock(&sb_lock);
- if (p)
- __put_super(p);
- p = sb;
- }
- if (p)
- __put_super(p);
- spin_unlock(&sb_lock);
- kfree(work);
- printk("Emergency Remount complete\n");
- }
- void emergency_remount(void)
- {
- struct work_struct *work;
- work = kmalloc(sizeof(*work), GFP_ATOMIC);
- if (work) {
- INIT_WORK(work, do_emergency_remount);
- schedule_work(work);
- }
- }
- static DEFINE_IDA(unnamed_dev_ida);
- static DEFINE_SPINLOCK(unnamed_dev_lock);
- static int unnamed_dev_start = 1;
- int get_anon_bdev(dev_t *p)
- {
- int dev;
- int error;
- retry:
- if (ida_pre_get(&unnamed_dev_ida, GFP_ATOMIC) == 0)
- return -ENOMEM;
- spin_lock(&unnamed_dev_lock);
- error = ida_get_new_above(&unnamed_dev_ida, unnamed_dev_start, &dev);
- if (!error)
- unnamed_dev_start = dev + 1;
- spin_unlock(&unnamed_dev_lock);
- if (error == -EAGAIN)
-
- goto retry;
- else if (error)
- return -EAGAIN;
- if (dev >= (1 << MINORBITS)) {
- spin_lock(&unnamed_dev_lock);
- ida_remove(&unnamed_dev_ida, dev);
- if (unnamed_dev_start > dev)
- unnamed_dev_start = dev;
- spin_unlock(&unnamed_dev_lock);
- return -EMFILE;
- }
- *p = MKDEV(0, dev & MINORMASK);
- return 0;
- }
- EXPORT_SYMBOL(get_anon_bdev);
- void free_anon_bdev(dev_t dev)
- {
- int slot = MINOR(dev);
- spin_lock(&unnamed_dev_lock);
- ida_remove(&unnamed_dev_ida, slot);
- if (slot < unnamed_dev_start)
- unnamed_dev_start = slot;
- spin_unlock(&unnamed_dev_lock);
- }
- EXPORT_SYMBOL(free_anon_bdev);
- int set_anon_super(struct super_block *s, void *data)
- {
- return get_anon_bdev(&s->s_dev);
- }
- EXPORT_SYMBOL(set_anon_super);
- void kill_anon_super(struct super_block *sb)
- {
- dev_t dev = sb->s_dev;
- generic_shutdown_super(sb);
- free_anon_bdev(dev);
- }
- EXPORT_SYMBOL(kill_anon_super);
- void kill_litter_super(struct super_block *sb)
- {
- if (sb->s_root)
- d_genocide(sb->s_root);
- kill_anon_super(sb);
- }
- EXPORT_SYMBOL(kill_litter_super);
- static int ns_test_super(struct super_block *sb, void *data)
- {
- return sb->s_fs_info == data;
- }
- static int ns_set_super(struct super_block *sb, void *data)
- {
- sb->s_fs_info = data;
- return set_anon_super(sb, NULL);
- }
- struct dentry *mount_ns(struct file_system_type *fs_type,
- int flags, void *data, void *ns, struct user_namespace *user_ns,
- int (*fill_super)(struct super_block *, void *, int))
- {
- struct super_block *sb;
-
- if (!(flags & MS_KERNMOUNT) && !ns_capable(user_ns, CAP_SYS_ADMIN))
- return ERR_PTR(-EPERM);
- sb = sget_userns(fs_type, ns_test_super, ns_set_super, flags,
- user_ns, ns);
- if (IS_ERR(sb))
- return ERR_CAST(sb);
- if (!sb->s_root) {
- int err;
- err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
- if (err) {
- deactivate_locked_super(sb);
- return ERR_PTR(err);
- }
- sb->s_flags |= MS_ACTIVE;
- }
- return dget(sb->s_root);
- }
- EXPORT_SYMBOL(mount_ns);
- #ifdef CONFIG_BLOCK
- static int set_bdev_super(struct super_block *s, void *data)
- {
- s->s_bdev = data;
- s->s_dev = s->s_bdev->bd_dev;
-
- s->s_bdi = bdev_get_queue(s->s_bdev)->backing_dev_info;
- return 0;
- }
- static int test_bdev_super(struct super_block *s, void *data)
- {
- return (void *)s->s_bdev == data;
- }
- struct dentry *mount_bdev(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data,
- int (*fill_super)(struct super_block *, void *, int))
- {
- struct block_device *bdev;
- struct super_block *s;
- fmode_t mode = FMODE_READ | FMODE_EXCL;
- int error = 0;
- if (!(flags & MS_RDONLY))
- mode |= FMODE_WRITE;
- bdev = blkdev_get_by_path(dev_name, mode, fs_type);
- if (IS_ERR(bdev))
- return ERR_CAST(bdev);
-
- mutex_lock(&bdev->bd_fsfreeze_mutex);
- if (bdev->bd_fsfreeze_count > 0) {
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- error = -EBUSY;
- goto error_bdev;
- }
- s = sget(fs_type, test_bdev_super, set_bdev_super, flags | MS_NOSEC,
- bdev);
- mutex_unlock(&bdev->bd_fsfreeze_mutex);
- if (IS_ERR(s))
- goto error_s;
- if (s->s_root) {
- if ((flags ^ s->s_flags) & MS_RDONLY) {
- deactivate_locked_super(s);
- error = -EBUSY;
- goto error_bdev;
- }
-
- up_write(&s->s_umount);
- blkdev_put(bdev, mode);
- down_write(&s->s_umount);
- } else {
- s->s_mode = mode;
- snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
- sb_set_blocksize(s, block_size(bdev));
- error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
- if (error) {
- deactivate_locked_super(s);
- goto error;
- }
- s->s_flags |= MS_ACTIVE;
- bdev->bd_super = s;
- }
- return dget(s->s_root);
- error_s:
- error = PTR_ERR(s);
- error_bdev:
- blkdev_put(bdev, mode);
- error:
- return ERR_PTR(error);
- }
- EXPORT_SYMBOL(mount_bdev);
- void kill_block_super(struct super_block *sb)
- {
- struct block_device *bdev = sb->s_bdev;
- fmode_t mode = sb->s_mode;
- bdev->bd_super = NULL;
- generic_shutdown_super(sb);
- sync_blockdev(bdev);
- WARN_ON_ONCE(!(mode & FMODE_EXCL));
- blkdev_put(bdev, mode | FMODE_EXCL);
- }
- EXPORT_SYMBOL(kill_block_super);
- #endif
- struct dentry *mount_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 = sget(fs_type, NULL, set_anon_super, flags, NULL);
- if (IS_ERR(s))
- return ERR_CAST(s);
- error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
- if (error) {
- deactivate_locked_super(s);
- return ERR_PTR(error);
- }
- s->s_flags |= MS_ACTIVE;
- return dget(s->s_root);
- }
- EXPORT_SYMBOL(mount_nodev);
- static int compare_single(struct super_block *s, void *p)
- {
- return 1;
- }
- struct dentry *mount_single(struct file_system_type *fs_type,
- int flags, void *data,
- int (*fill_super)(struct super_block *, void *, int))
- {
- struct super_block *s;
- int error;
- s = sget(fs_type, compare_single, set_anon_super, flags, NULL);
- if (IS_ERR(s))
- return ERR_CAST(s);
- if (!s->s_root) {
- error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
- if (error) {
- deactivate_locked_super(s);
- return ERR_PTR(error);
- }
- s->s_flags |= MS_ACTIVE;
- } else {
- do_remount_sb(s, flags, data, 0);
- }
- return dget(s->s_root);
- }
- EXPORT_SYMBOL(mount_single);
- struct dentry *
- mount_fs(struct file_system_type *type, int flags, const char *name, struct vfsmount *mnt, void *data)
- {
- struct dentry *root;
- struct super_block *sb;
- char *secdata = NULL;
- int error = -ENOMEM;
- if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
- secdata = alloc_secdata();
- if (!secdata)
- goto out;
- error = security_sb_copy_data(data, secdata);
- if (error)
- goto out_free_secdata;
- }
- if (type->mount2)
- root = type->mount2(mnt, type, flags, name, data);
- else
- root = type->mount(type, flags, name, data);
- if (IS_ERR(root)) {
- error = PTR_ERR(root);
- goto out_free_secdata;
- }
- sb = root->d_sb;
- BUG_ON(!sb);
- WARN_ON(!sb->s_bdi);
-
- smp_wmb();
- sb->s_flags |= MS_BORN;
- error = security_sb_kern_mount(sb, flags, secdata);
- if (error)
- goto out_sb;
-
- WARN((sb->s_maxbytes < 0), "%s set sb->s_maxbytes to "
- "negative value (%lld)\n", type->name, sb->s_maxbytes);
- up_write(&sb->s_umount);
- free_secdata(secdata);
- return root;
- out_sb:
- dput(root);
- deactivate_locked_super(sb);
- out_free_secdata:
- free_secdata(secdata);
- out:
- return ERR_PTR(error);
- }
- void __sb_end_write(struct super_block *sb, int level)
- {
- percpu_up_read(sb->s_writers.rw_sem + level-1);
- }
- EXPORT_SYMBOL(__sb_end_write);
- int __sb_start_write(struct super_block *sb, int level, bool wait)
- {
- bool force_trylock = false;
- int ret = 1;
- #ifdef CONFIG_LOCKDEP
-
- if (wait) {
- int i;
- for (i = 0; i < level - 1; i++)
- if (percpu_rwsem_is_held(sb->s_writers.rw_sem + i)) {
- force_trylock = true;
- break;
- }
- }
- #endif
- if (wait && !force_trylock)
- percpu_down_read(sb->s_writers.rw_sem + level-1);
- else
- ret = percpu_down_read_trylock(sb->s_writers.rw_sem + level-1);
- WARN_ON(force_trylock && !ret);
- return ret;
- }
- EXPORT_SYMBOL(__sb_start_write);
- static void sb_wait_write(struct super_block *sb, int level)
- {
- percpu_down_write(sb->s_writers.rw_sem + level-1);
- }
- static void lockdep_sb_freeze_release(struct super_block *sb)
- {
- int level;
- for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
- percpu_rwsem_release(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
- }
- static void lockdep_sb_freeze_acquire(struct super_block *sb)
- {
- int level;
- for (level = 0; level < SB_FREEZE_LEVELS; ++level)
- percpu_rwsem_acquire(sb->s_writers.rw_sem + level, 0, _THIS_IP_);
- }
- static void sb_freeze_unlock(struct super_block *sb)
- {
- int level;
- for (level = SB_FREEZE_LEVELS - 1; level >= 0; level--)
- percpu_up_write(sb->s_writers.rw_sem + level);
- }
- int freeze_super(struct super_block *sb)
- {
- int ret;
- atomic_inc(&sb->s_active);
- down_write(&sb->s_umount);
- if (sb->s_writers.frozen != SB_UNFROZEN) {
- deactivate_locked_super(sb);
- return -EBUSY;
- }
- if (!(sb->s_flags & MS_BORN)) {
- up_write(&sb->s_umount);
- return 0;
- }
- if (sb->s_flags & MS_RDONLY) {
-
- sb->s_writers.frozen = SB_FREEZE_COMPLETE;
- up_write(&sb->s_umount);
- return 0;
- }
- sb->s_writers.frozen = SB_FREEZE_WRITE;
-
- up_write(&sb->s_umount);
- sb_wait_write(sb, SB_FREEZE_WRITE);
- down_write(&sb->s_umount);
-
- sb->s_writers.frozen = SB_FREEZE_PAGEFAULT;
- sb_wait_write(sb, SB_FREEZE_PAGEFAULT);
-
- sync_filesystem(sb);
-
- sb->s_writers.frozen = SB_FREEZE_FS;
- sb_wait_write(sb, SB_FREEZE_FS);
- if (sb->s_op->freeze_fs) {
- ret = sb->s_op->freeze_fs(sb);
- if (ret) {
- printk(KERN_ERR
- "VFS:Filesystem freeze failed\n");
- sb->s_writers.frozen = SB_UNFROZEN;
- sb_freeze_unlock(sb);
- wake_up(&sb->s_writers.wait_unfrozen);
- deactivate_locked_super(sb);
- return ret;
- }
- }
-
- sb->s_writers.frozen = SB_FREEZE_COMPLETE;
- lockdep_sb_freeze_release(sb);
- up_write(&sb->s_umount);
- return 0;
- }
- EXPORT_SYMBOL(freeze_super);
- int thaw_super(struct super_block *sb)
- {
- int error;
- down_write(&sb->s_umount);
- if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
- up_write(&sb->s_umount);
- return -EINVAL;
- }
- if (sb->s_flags & MS_RDONLY) {
- sb->s_writers.frozen = SB_UNFROZEN;
- goto out;
- }
- lockdep_sb_freeze_acquire(sb);
- if (sb->s_op->unfreeze_fs) {
- error = sb->s_op->unfreeze_fs(sb);
- if (error) {
- printk(KERN_ERR
- "VFS:Filesystem thaw failed\n");
- lockdep_sb_freeze_release(sb);
- up_write(&sb->s_umount);
- return error;
- }
- }
- sb->s_writers.frozen = SB_UNFROZEN;
- sb_freeze_unlock(sb);
- out:
- wake_up(&sb->s_writers.wait_unfrozen);
- deactivate_locked_super(sb);
- return 0;
- }
- EXPORT_SYMBOL(thaw_super);
|