/* * hugetlbpage-backed filesystem. Based on ramfs. * * William Irwin, 2002 * * Copyright (C) 2002 Linus Torvalds. */ #include <linux/module.h> #include <linux/thread_info.h> #include <asm/current.h> #include <linux/sched.h> /* remove ASAP */ #include <linux/fs.h> #include <linux/mount.h> #include <linux/file.h> #include <linux/writeback.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/init.h> #include <linux/string.h> #include <linux/capability.h> #include <linux/backing-dev.h> #include <linux/hugetlb.h> #include <linux/pagevec.h> #include <linux/quotaops.h> #include <linux/slab.h> #include <linux/dnotify.h> #include <linux/statfs.h> #include <linux/security.h> #include <asm/uaccess.h> /* some random number */ #define HUGETLBFS_MAGIC 0x958458f6 static struct super_operations hugetlbfs_ops; static const struct address_space_operations hugetlbfs_aops; const struct file_operations hugetlbfs_file_operations; static struct inode_operations hugetlbfs_dir_inode_operations; static struct inode_operations hugetlbfs_inode_operations; static struct backing_dev_info hugetlbfs_backing_dev_info = { .ra_pages = 0, /* No readahead */ .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, }; int sysctl_hugetlb_shm_group; static void huge_pagevec_release(struct pagevec *pvec) { int i; for (i = 0; i < pagevec_count(pvec); ++i) put_page(pvec->pages[i]); pagevec_reinit(pvec); } static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) { struct inode *inode = file->f_dentry->d_inode; loff_t len, vma_len; int ret; /* * vma alignment has already been checked by prepare_hugepage_range. * If you add any error returns here, do so after setting VM_HUGETLB, * so is_vm_hugetlb_page tests below unmap_region go the right way * when do_mmap_pgoff unwinds (may be important on powerpc and ia64). */ vma->vm_flags |= VM_HUGETLB | VM_RESERVED; vma->vm_ops = &hugetlb_vm_ops; vma_len = (loff_t)(vma->vm_end - vma->vm_start); mutex_lock(&inode->i_mutex); file_accessed(file); ret = -ENOMEM; len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); if (vma->vm_flags & VM_MAYSHARE && hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT), len >> HPAGE_SHIFT)) goto out; ret = 0; hugetlb_prefault_arch_hook(vma->vm_mm); if (vma->vm_flags & VM_WRITE && inode->i_size < len) inode->i_size = len; out: mutex_unlock(&inode->i_mutex); return ret; } /* * Called under down_write(mmap_sem). */ #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #else static unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; unsigned long start_addr; if (len & ~HPAGE_MASK) return -EINVAL; if (len > TASK_SIZE) return -ENOMEM; if (addr) { addr = ALIGN(addr, HPAGE_SIZE); vma = find_vma(mm, addr); if (TASK_SIZE - len >= addr && (!vma || addr + len <= vma->vm_start)) return addr; } start_addr = mm->free_area_cache; if (len <= mm->cached_hole_size) start_addr = TASK_UNMAPPED_BASE; full_search: addr = ALIGN(start_addr, HPAGE_SIZE); for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { /* At this point: (!vma || addr < vma->vm_end). */ if (TASK_SIZE - len < addr) { /* * Start a new search - just in case we missed * some holes. */ if (start_addr != TASK_UNMAPPED_BASE) { start_addr = TASK_UNMAPPED_BASE; goto full_search; } return -ENOMEM; } if (!vma || addr + len <= vma->vm_start) return addr; addr = ALIGN(vma->vm_end, HPAGE_SIZE); } } #endif /* * Read a page. Again trivial. If it didn't already exist * in the page cache, it is zero-filled. */ static int hugetlbfs_readpage(struct file *file, struct page * page) { unlock_page(page); return -EINVAL; } static int hugetlbfs_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) { return -EINVAL; } static int hugetlbfs_commit_write(struct file *file, struct page *page, unsigned offset, unsigned to) { return -EINVAL; } static void truncate_huge_page(struct page *page) { clear_page_dirty(page); ClearPageUptodate(page); remove_from_page_cache(page); put_page(page); } static void truncate_hugepages(struct inode *inode, loff_t lstart) { struct address_space *mapping = &inode->i_data; const pgoff_t start = lstart >> HPAGE_SHIFT; struct pagevec pvec; pgoff_t next; int i, freed = 0; pagevec_init(&pvec, 0); next = start; while (1) { if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) { if (next == start) break; next = start; continue; } for (i = 0; i < pagevec_count(&pvec); ++i) { struct page *page = pvec.pages[i]; lock_page(page); if (page->index > next) next = page->index; ++next; truncate_huge_page(page); unlock_page(page); hugetlb_put_quota(mapping); freed++; } huge_pagevec_release(&pvec); } BUG_ON(!lstart && mapping->nrpages); hugetlb_unreserve_pages(inode, start, freed); } static void hugetlbfs_delete_inode(struct inode *inode) { truncate_hugepages(inode, 0); clear_inode(inode); } static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock) { struct super_block *sb = inode->i_sb; if (!hlist_unhashed(&inode->i_hash)) { if (!(inode->i_state & (I_DIRTY|I_LOCK))) list_move(&inode->i_list, &inode_unused); inodes_stat.nr_unused++; if (!sb || (sb->s_flags & MS_ACTIVE)) { spin_unlock(&inode_lock); return; } inode->i_state |= I_WILL_FREE; spin_unlock(&inode_lock); /* * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK * in our backing_dev_info. */ write_inode_now(inode, 1); spin_lock(&inode_lock); inode->i_state &= ~I_WILL_FREE; inodes_stat.nr_unused--; hlist_del_init(&inode->i_hash); } list_del_init(&inode->i_list); list_del_init(&inode->i_sb_list); inode->i_state |= I_FREEING; inodes_stat.nr_inodes--; spin_unlock(&inode_lock); truncate_hugepages(inode, 0); clear_inode(inode); destroy_inode(inode); } static void hugetlbfs_drop_inode(struct inode *inode) { if (!inode->i_nlink) generic_delete_inode(inode); else hugetlbfs_forget_inode(inode); } static inline void hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff) { struct vm_area_struct *vma; struct prio_tree_iter iter; vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) { unsigned long v_offset; /* * Can the expression below overflow on 32-bit arches? * No, because the prio_tree returns us only those vmas * which overlap the truncated area starting at pgoff, * and no vma on a 32-bit arch can span beyond the 4GB. */ if (vma->vm_pgoff < pgoff) v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT; else v_offset = 0; __unmap_hugepage_range(vma, vma->vm_start + v_offset, vma->vm_end); } } /* * Expanding truncates are not allowed. */ static int hugetlb_vmtruncate(struct inode *inode, loff_t offset) { pgoff_t pgoff; struct address_space *mapping = inode->i_mapping; if (offset > inode->i_size) return -EINVAL; BUG_ON(offset & ~HPAGE_MASK); pgoff = offset >> PAGE_SHIFT; inode->i_size = offset; spin_lock(&mapping->i_mmap_lock); if (!prio_tree_empty(&mapping->i_mmap)) hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff); spin_unlock(&mapping->i_mmap_lock); truncate_hugepages(inode, offset); return 0; } static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; int error; unsigned int ia_valid = attr->ia_valid; BUG_ON(!inode); error = inode_change_ok(inode, attr); if (error) goto out; if (ia_valid & ATTR_SIZE) { error = -EINVAL; if (!(attr->ia_size & ~HPAGE_MASK)) error = hugetlb_vmtruncate(inode, attr->ia_size); if (error) goto out; attr->ia_valid &= ~ATTR_SIZE; } error = inode_setattr(inode, attr); out: return error; } static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, gid_t gid, int mode, dev_t dev) { struct inode *inode; inode = new_inode(sb); if (inode) { struct hugetlbfs_inode_info *info; inode->i_mode = mode; inode->i_uid = uid; inode->i_gid = gid; inode->i_blocks = 0; inode->i_mapping->a_ops = &hugetlbfs_aops; inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; INIT_LIST_HEAD(&inode->i_mapping->private_list); info = HUGETLBFS_I(inode); mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL); switch (mode & S_IFMT) { default: init_special_inode(inode, mode, dev); break; case S_IFREG: inode->i_op = &hugetlbfs_inode_operations; inode->i_fop = &hugetlbfs_file_operations; break; case S_IFDIR: inode->i_op = &hugetlbfs_dir_inode_operations; inode->i_fop = &simple_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inc_nlink(inode); break; case S_IFLNK: inode->i_op = &page_symlink_inode_operations; break; } } return inode; } /* * File creation. Allocate an inode, and we're done.. */ static int hugetlbfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) { struct inode *inode; int error = -ENOSPC; gid_t gid; if (dir->i_mode & S_ISGID) { gid = dir->i_gid; if (S_ISDIR(mode)) mode |= S_ISGID; } else { gid = current->fsgid; } inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev); if (inode) { dir->i_ctime = dir->i_mtime = CURRENT_TIME; d_instantiate(dentry, inode); dget(dentry); /* Extra count - pin the dentry in core */ error = 0; } return error; } static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) { int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0); if (!retval) inc_nlink(dir); return retval; } static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) { return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0); } static int hugetlbfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { struct inode *inode; int error = -ENOSPC; gid_t gid; if (dir->i_mode & S_ISGID) gid = dir->i_gid; else gid = current->fsgid; inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, S_IFLNK|S_IRWXUGO, 0); if (inode) { int l = strlen(symname)+1; error = page_symlink(inode, symname, l); if (!error) { d_instantiate(dentry, inode); dget(dentry); } else iput(inode); } dir->i_ctime = dir->i_mtime = CURRENT_TIME; return error; } /* * For direct-IO reads into hugetlb pages */ static int hugetlbfs_set_page_dirty(struct page *page) { return 0; } static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) { struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb); buf->f_type = HUGETLBFS_MAGIC; buf->f_bsize = HPAGE_SIZE; if (sbinfo) { spin_lock(&sbinfo->stat_lock); /* If no limits set, just report 0 for max/free/used * blocks, like simple_statfs() */ if (sbinfo->max_blocks >= 0) { buf->f_blocks = sbinfo->max_blocks; buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; buf->f_files = sbinfo->max_inodes; buf->f_ffree = sbinfo->free_inodes; } spin_unlock(&sbinfo->stat_lock); } buf->f_namelen = NAME_MAX; return 0; } static void hugetlbfs_put_super(struct super_block *sb) { struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb); if (sbi) { sb->s_fs_info = NULL; kfree(sbi); } } static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo) { if (sbinfo->free_inodes >= 0) { spin_lock(&sbinfo->stat_lock); if (unlikely(!sbinfo->free_inodes)) { spin_unlock(&sbinfo->stat_lock); return 0; } sbinfo->free_inodes--; spin_unlock(&sbinfo->stat_lock); } return 1; } static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo) { if (sbinfo->free_inodes >= 0) { spin_lock(&sbinfo->stat_lock); sbinfo->free_inodes++; spin_unlock(&sbinfo->stat_lock); } } static kmem_cache_t *hugetlbfs_inode_cachep; static struct inode *hugetlbfs_alloc_inode(struct super_block *sb) { struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb); struct hugetlbfs_inode_info *p; if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo))) return NULL; p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL); if (unlikely(!p)) { hugetlbfs_inc_free_inodes(sbinfo); return NULL; } return &p->vfs_inode; } static void hugetlbfs_destroy_inode(struct inode *inode) { hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb)); mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode)); } static const struct address_space_operations hugetlbfs_aops = { .readpage = hugetlbfs_readpage, .prepare_write = hugetlbfs_prepare_write, .commit_write = hugetlbfs_commit_write, .set_page_dirty = hugetlbfs_set_page_dirty, }; static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) { struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo; if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR) inode_init_once(&ei->vfs_inode); } const struct file_operations hugetlbfs_file_operations = { .mmap = hugetlbfs_file_mmap, .fsync = simple_sync_file, .get_unmapped_area = hugetlb_get_unmapped_area, }; static struct inode_operations hugetlbfs_dir_inode_operations = { .create = hugetlbfs_create, .lookup = simple_lookup, .link = simple_link, .unlink = simple_unlink, .symlink = hugetlbfs_symlink, .mkdir = hugetlbfs_mkdir, .rmdir = simple_rmdir, .mknod = hugetlbfs_mknod, .rename = simple_rename, .setattr = hugetlbfs_setattr, }; static struct inode_operations hugetlbfs_inode_operations = { .setattr = hugetlbfs_setattr, }; static struct super_operations hugetlbfs_ops = { .alloc_inode = hugetlbfs_alloc_inode, .destroy_inode = hugetlbfs_destroy_inode, .statfs = hugetlbfs_statfs, .delete_inode = hugetlbfs_delete_inode, .drop_inode = hugetlbfs_drop_inode, .put_super = hugetlbfs_put_super, }; static int hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig) { char *opt, *value, *rest; if (!options) return 0; while ((opt = strsep(&options, ",")) != NULL) { if (!*opt) continue; value = strchr(opt, '='); if (!value || !*value) return -EINVAL; else *value++ = '\0'; if (!strcmp(opt, "uid")) pconfig->uid = simple_strtoul(value, &value, 0); else if (!strcmp(opt, "gid")) pconfig->gid = simple_strtoul(value, &value, 0); else if (!strcmp(opt, "mode")) pconfig->mode = simple_strtoul(value,&value,0) & 0777U; else if (!strcmp(opt, "size")) { unsigned long long size = memparse(value, &rest); if (*rest == '%') { size <<= HPAGE_SHIFT; size *= max_huge_pages; do_div(size, 100); rest++; } pconfig->nr_blocks = (size >> HPAGE_SHIFT); value = rest; } else if (!strcmp(opt,"nr_inodes")) { pconfig->nr_inodes = memparse(value, &rest); value = rest; } else return -EINVAL; if (*value) return -EINVAL; } return 0; } static int hugetlbfs_fill_super(struct super_block *sb, void *data, int silent) { struct inode * inode; struct dentry * root; int ret; struct hugetlbfs_config config; struct hugetlbfs_sb_info *sbinfo; config.nr_blocks = -1; /* No limit on size by default */ config.nr_inodes = -1; /* No limit on number of inodes by default */ config.uid = current->fsuid; config.gid = current->fsgid; config.mode = 0755; ret = hugetlbfs_parse_options(data, &config); if (ret) return ret; sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL); if (!sbinfo) return -ENOMEM; sb->s_fs_info = sbinfo; spin_lock_init(&sbinfo->stat_lock); sbinfo->max_blocks = config.nr_blocks; sbinfo->free_blocks = config.nr_blocks; sbinfo->max_inodes = config.nr_inodes; sbinfo->free_inodes = config.nr_inodes; sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_blocksize = HPAGE_SIZE; sb->s_blocksize_bits = HPAGE_SHIFT; sb->s_magic = HUGETLBFS_MAGIC; sb->s_op = &hugetlbfs_ops; sb->s_time_gran = 1; inode = hugetlbfs_get_inode(sb, config.uid, config.gid, S_IFDIR | config.mode, 0); if (!inode) goto out_free; root = d_alloc_root(inode); if (!root) { iput(inode); goto out_free; } sb->s_root = root; return 0; out_free: kfree(sbinfo); return -ENOMEM; } int hugetlb_get_quota(struct address_space *mapping) { int ret = 0; struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); if (sbinfo->free_blocks > -1) { spin_lock(&sbinfo->stat_lock); if (sbinfo->free_blocks > 0) sbinfo->free_blocks--; else ret = -ENOMEM; spin_unlock(&sbinfo->stat_lock); } return ret; } void hugetlb_put_quota(struct address_space *mapping) { struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb); if (sbinfo->free_blocks > -1) { spin_lock(&sbinfo->stat_lock); sbinfo->free_blocks++; spin_unlock(&sbinfo->stat_lock); } } static int hugetlbfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt); } static struct file_system_type hugetlbfs_fs_type = { .name = "hugetlbfs", .get_sb = hugetlbfs_get_sb, .kill_sb = kill_litter_super, }; static struct vfsmount *hugetlbfs_vfsmount; static int can_do_hugetlb_shm(void) { return likely(capable(CAP_IPC_LOCK) || in_group_p(sysctl_hugetlb_shm_group) || can_do_mlock()); } struct file *hugetlb_zero_setup(size_t size) { int error = -ENOMEM; struct file *file; struct inode *inode; struct dentry *dentry, *root; struct qstr quick_string; char buf[16]; static atomic_t counter; if (!can_do_hugetlb_shm()) return ERR_PTR(-EPERM); if (!user_shm_lock(size, current->user)) return ERR_PTR(-ENOMEM); root = hugetlbfs_vfsmount->mnt_root; snprintf(buf, 16, "%u", atomic_inc_return(&counter)); quick_string.name = buf; quick_string.len = strlen(quick_string.name); quick_string.hash = 0; dentry = d_alloc(root, &quick_string); if (!dentry) goto out_shm_unlock; error = -ENFILE; file = get_empty_filp(); if (!file) goto out_dentry; error = -ENOSPC; inode = hugetlbfs_get_inode(root->d_sb, current->fsuid, current->fsgid, S_IFREG | S_IRWXUGO, 0); if (!inode) goto out_file; error = -ENOMEM; if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT)) goto out_inode; d_instantiate(dentry, inode); inode->i_size = size; inode->i_nlink = 0; file->f_vfsmnt = mntget(hugetlbfs_vfsmount); file->f_dentry = dentry; file->f_mapping = inode->i_mapping; file->f_op = &hugetlbfs_file_operations; file->f_mode = FMODE_WRITE | FMODE_READ; return file; out_inode: iput(inode); out_file: put_filp(file); out_dentry: dput(dentry); out_shm_unlock: user_shm_unlock(size, current->user); return ERR_PTR(error); } static int __init init_hugetlbfs_fs(void) { int error; struct vfsmount *vfsmount; hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache", sizeof(struct hugetlbfs_inode_info), 0, 0, init_once, NULL); if (hugetlbfs_inode_cachep == NULL) return -ENOMEM; error = register_filesystem(&hugetlbfs_fs_type); if (error) goto out; vfsmount = kern_mount(&hugetlbfs_fs_type); if (!IS_ERR(vfsmount)) { hugetlbfs_vfsmount = vfsmount; return 0; } error = PTR_ERR(vfsmount); out: if (error) kmem_cache_destroy(hugetlbfs_inode_cachep); return error; } static void __exit exit_hugetlbfs_fs(void) { kmem_cache_destroy(hugetlbfs_inode_cachep); unregister_filesystem(&hugetlbfs_fs_type); } module_init(init_hugetlbfs_fs) module_exit(exit_hugetlbfs_fs) MODULE_LICENSE("GPL");