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-rw-r--r--fs/hugetlbfs/inode.c853
1 files changed, 853 insertions, 0 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
new file mode 100644
index 00000000000..2af3338f891
--- /dev/null
+++ b/fs/hugetlbfs/inode.c
@@ -0,0 +1,853 @@
+/*
+ * 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/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 struct address_space_operations hugetlbfs_aops;
+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 int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct address_space *mapping = inode->i_mapping;
+ loff_t len, vma_len;
+ int ret;
+
+ if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
+ return -EINVAL;
+
+ if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
+ return -EINVAL;
+
+ if (vma->vm_start & ~HPAGE_MASK)
+ return -EINVAL;
+
+ if (vma->vm_end & ~HPAGE_MASK)
+ return -EINVAL;
+
+ if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
+ return -EINVAL;
+
+ vma_len = (loff_t)(vma->vm_end - vma->vm_start);
+
+ down(&inode->i_sem);
+ file_accessed(file);
+ vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
+ vma->vm_ops = &hugetlb_vm_ops;
+
+ ret = -ENOMEM;
+ len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+ if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
+ goto out;
+
+ ret = hugetlb_prefault(mapping, vma);
+ if (ret)
+ goto out;
+
+ if (inode->i_size < len)
+ inode->i_size = len;
+out:
+ up(&inode->i_sem);
+
+ return ret;
+}
+
+/*
+ * Called under down_write(mmap_sem), page_table_lock is not held
+ */
+
+#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;
+
+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 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 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 address_space *mapping, loff_t lstart)
+{
+ const pgoff_t start = lstart >> HPAGE_SHIFT;
+ struct pagevec pvec;
+ pgoff_t next;
+ int i;
+
+ 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);
+ }
+ huge_pagevec_release(&pvec);
+ }
+ BUG_ON(!lstart && mapping->nrpages);
+}
+
+static void hugetlbfs_delete_inode(struct inode *inode)
+{
+ struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(inode->i_sb);
+
+ 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);
+
+ if (inode->i_data.nrpages)
+ truncate_hugepages(&inode->i_data, 0);
+
+ security_inode_delete(inode);
+
+ if (sbinfo->free_inodes >= 0) {
+ spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_inodes++;
+ spin_unlock(&sbinfo->stat_lock);
+ }
+
+ clear_inode(inode);
+ destroy_inode(inode);
+}
+
+static void hugetlbfs_forget_inode(struct inode *inode)
+{
+ struct super_block *super_block = inode->i_sb;
+ struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(super_block);
+
+ if (hlist_unhashed(&inode->i_hash))
+ goto out_truncate;
+
+ if (!(inode->i_state & (I_DIRTY|I_LOCK))) {
+ list_del(&inode->i_list);
+ list_add(&inode->i_list, &inode_unused);
+ }
+ inodes_stat.nr_unused++;
+ if (!super_block || (super_block->s_flags & MS_ACTIVE)) {
+ spin_unlock(&inode_lock);
+ return;
+ }
+
+ /* write_inode_now() ? */
+ inodes_stat.nr_unused--;
+ hlist_del_init(&inode->i_hash);
+out_truncate:
+ 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);
+ if (inode->i_data.nrpages)
+ truncate_hugepages(&inode->i_data, 0);
+
+ if (sbinfo->free_inodes >= 0) {
+ spin_lock(&sbinfo->stat_lock);
+ sbinfo->free_inodes++;
+ spin_unlock(&sbinfo->stat_lock);
+ }
+
+ clear_inode(inode);
+ destroy_inode(inode);
+}
+
+static void hugetlbfs_drop_inode(struct inode *inode)
+{
+ if (!inode->i_nlink)
+ hugetlbfs_delete_inode(inode);
+ else
+ hugetlbfs_forget_inode(inode);
+}
+
+/*
+ * h_pgoff is in HPAGE_SIZE units.
+ * vma->vm_pgoff is in PAGE_SIZE units.
+ */
+static inline void
+hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
+{
+ struct vm_area_struct *vma;
+ struct prio_tree_iter iter;
+
+ vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
+ unsigned long h_vm_pgoff;
+ unsigned long v_length;
+ unsigned long v_offset;
+
+ h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
+ v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
+ /*
+ * Is this VMA fully outside the truncation point?
+ */
+ if (h_vm_pgoff >= h_pgoff)
+ v_offset = 0;
+
+ v_length = vma->vm_end - vma->vm_start;
+
+ zap_hugepage_range(vma,
+ vma->vm_start + v_offset,
+ v_length - v_offset);
+ }
+}
+
+/*
+ * Expanding truncates are not allowed.
+ */
+static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
+{
+ unsigned long pgoff;
+ struct address_space *mapping = inode->i_mapping;
+
+ if (offset > inode->i_size)
+ return -EINVAL;
+
+ BUG_ON(offset & ~HPAGE_MASK);
+ pgoff = offset >> HPAGE_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(mapping, 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;
+ struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
+
+ if (sbinfo->free_inodes >= 0) {
+ spin_lock(&sbinfo->stat_lock);
+ if (!sbinfo->free_inodes) {
+ spin_unlock(&sbinfo->stat_lock);
+ return NULL;
+ }
+ sbinfo->free_inodes--;
+ spin_unlock(&sbinfo->stat_lock);
+ }
+
+ 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_blksize = HPAGE_SIZE;
+ 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;
+ info = HUGETLBFS_I(inode);
+ mpol_shared_policy_init(&info->policy);
+ 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) */
+ inode->i_nlink++;
+ 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)
+ dir->i_nlink++;
+ 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 super_block *sb, struct kstatfs *buf)
+{
+ struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
+
+ buf->f_type = HUGETLBFS_MAGIC;
+ buf->f_bsize = HPAGE_SIZE;
+ if (sbinfo) {
+ spin_lock(&sbinfo->stat_lock);
+ 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 kmem_cache_t *hugetlbfs_inode_cachep;
+
+static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
+{
+ struct hugetlbfs_inode_info *p;
+
+ p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
+ if (!p)
+ return NULL;
+ return &p->vfs_inode;
+}
+
+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);
+}
+
+static void hugetlbfs_destroy_inode(struct inode *inode)
+{
+ mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
+ kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
+}
+
+static 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,
+};
+
+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,
+ .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++;
+ }
+ size &= HPAGE_MASK;
+ 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 struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
+}
+
+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;
+
+/*
+ * Return the next identifier for a shm file
+ */
+static unsigned long hugetlbfs_counter(void)
+{
+ static DEFINE_SPINLOCK(lock);
+ static unsigned long counter;
+ unsigned long ret;
+
+ spin_lock(&lock);
+ ret = ++counter;
+ spin_unlock(&lock);
+ return ret;
+}
+
+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];
+
+ if (!can_do_hugetlb_shm())
+ return ERR_PTR(-EPERM);
+
+ if (!is_hugepage_mem_enough(size))
+ return ERR_PTR(-ENOMEM);
+
+ if (!user_shm_lock(size, current->user))
+ return ERR_PTR(-ENOMEM);
+
+ root = hugetlbfs_vfsmount->mnt_root;
+ snprintf(buf, 16, "%lu", hugetlbfs_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;
+
+ 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_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");