diff options
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 69 |
1 files changed, 54 insertions, 15 deletions
diff --git a/fs/super.c b/fs/super.c index 938119ab8dcb..8819e3a7ff20 100644 --- a/fs/super.c +++ b/fs/super.c @@ -54,7 +54,22 @@ static struct super_block *alloc_super(struct file_system_type *type) s = NULL; goto out; } +#ifdef CONFIG_SMP + s->s_files = alloc_percpu(struct list_head); + if (!s->s_files) { + security_sb_free(s); + kfree(s); + s = NULL; + goto out; + } else { + int i; + + for_each_possible_cpu(i) + INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i)); + } +#else INIT_LIST_HEAD(&s->s_files); +#endif INIT_LIST_HEAD(&s->s_instances); INIT_HLIST_HEAD(&s->s_anon); INIT_LIST_HEAD(&s->s_inodes); @@ -108,6 +123,9 @@ out: */ static inline void destroy_super(struct super_block *s) { +#ifdef CONFIG_SMP + free_percpu(s->s_files); +#endif security_sb_free(s); kfree(s->s_subtype); kfree(s->s_options); @@ -305,8 +323,13 @@ retry: if (s) { up_write(&s->s_umount); destroy_super(s); + s = NULL; } down_write(&old->s_umount); + if (unlikely(!(old->s_flags & MS_BORN))) { + deactivate_locked_super(old); + goto retry; + } return old; } } @@ -358,10 +381,10 @@ EXPORT_SYMBOL(drop_super); */ void sync_supers(void) { - struct super_block *sb, *n; + struct super_block *sb, *p = NULL; spin_lock(&sb_lock); - list_for_each_entry_safe(sb, n, &super_blocks, s_list) { + list_for_each_entry(sb, &super_blocks, s_list) { if (list_empty(&sb->s_instances)) continue; if (sb->s_op->write_super && sb->s_dirt) { @@ -374,11 +397,13 @@ void sync_supers(void) up_read(&sb->s_umount); spin_lock(&sb_lock); - /* lock was dropped, must reset next */ - list_safe_reset_next(sb, n, s_list); - __put_super(sb); + if (p) + __put_super(p); + p = sb; } } + if (p) + __put_super(p); spin_unlock(&sb_lock); } @@ -392,10 +417,10 @@ void sync_supers(void) */ void iterate_supers(void (*f)(struct super_block *, void *), void *arg) { - struct super_block *sb, *n; + struct super_block *sb, *p = NULL; spin_lock(&sb_lock); - list_for_each_entry_safe(sb, n, &super_blocks, s_list) { + list_for_each_entry(sb, &super_blocks, s_list) { if (list_empty(&sb->s_instances)) continue; sb->s_count++; @@ -407,10 +432,12 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg) up_read(&sb->s_umount); spin_lock(&sb_lock); - /* lock was dropped, must reset next */ - list_safe_reset_next(sb, n, s_list); - __put_super(sb); + if (p) + __put_super(p); + p = sb; } + if (p) + __put_super(p); spin_unlock(&sb_lock); } @@ -572,10 +599,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force) static void do_emergency_remount(struct work_struct *work) { - struct super_block *sb, *n; + struct super_block *sb, *p = NULL; spin_lock(&sb_lock); - list_for_each_entry_safe(sb, n, &super_blocks, s_list) { + list_for_each_entry(sb, &super_blocks, s_list) { if (list_empty(&sb->s_instances)) continue; sb->s_count++; @@ -589,10 +616,12 @@ static void do_emergency_remount(struct work_struct *work) } up_write(&sb->s_umount); spin_lock(&sb_lock); - /* lock was dropped, must reset next */ - list_safe_reset_next(sb, n, s_list); - __put_super(sb); + if (p) + __put_super(p); + p = sb; } + if (p) + __put_super(p); spin_unlock(&sb_lock); kfree(work); printk("Emergency Remount complete\n"); @@ -773,7 +802,16 @@ int get_sb_bdev(struct file_system_type *fs_type, goto error_bdev; } + /* + * s_umount nests inside bd_mutex during + * __invalidate_device(). close_bdev_exclusive() + * acquires bd_mutex and can't be called under + * s_umount. Drop s_umount temporarily. This is safe + * as we're holding an active reference. + */ + up_write(&s->s_umount); close_bdev_exclusive(bdev, mode); + down_write(&s->s_umount); } else { char b[BDEVNAME_SIZE]; @@ -909,6 +947,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void goto out_free_secdata; BUG_ON(!mnt->mnt_sb); WARN_ON(!mnt->mnt_sb->s_bdi); + mnt->mnt_sb->s_flags |= MS_BORN; error = security_sb_kern_mount(mnt->mnt_sb, flags, secdata); if (error) |