linux/fs/hugetlbfs/inode.c
David Gibson 74a8a65c52 [PATCH] Fix hugetlbfs_statfs() reporting of block limits
Currently, if a hugetlbfs is mounted without limits (the default), statfs()
will return -1 for max/free/used blocks.  This does not appear to be in
line with normal convention: simple_statfs() and shmem_statfs() both return
0 in similar cases.  Worse, it confuses the translation logic in
put_compat_statfs(), causing it to return -EOVERFLOW on such a mount.

This patch alters hugetlbfs_statfs() to return 0 for max/free/used blocks
on a mount without limits.  Note that we need the test in the patch below,
rather than just using 0 in the sbinfo structure, because the -1 marked in
the free blocks field is used internally to tell the

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-22 09:13:43 -08:00

894 lines
21 KiB
C

/*
* 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 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);
}
/*
* huge_pages_needed tries to determine the number of new huge pages that
* will be required to fully populate this VMA. This will be equal to
* the size of the VMA in huge pages minus the number of huge pages
* (covered by this VMA) that are found in the page cache.
*
* Result is in bytes to be compatible with is_hugepage_mem_enough()
*/
static unsigned long
huge_pages_needed(struct address_space *mapping, struct vm_area_struct *vma)
{
int i;
struct pagevec pvec;
unsigned long start = vma->vm_start;
unsigned long end = vma->vm_end;
unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
pgoff_t next = vma->vm_pgoff;
pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
pagevec_init(&pvec, 0);
while (next < endpg) {
if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
break;
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
if (page->index > next)
next = page->index;
if (page->index >= endpg)
break;
next++;
hugepages--;
}
huge_pagevec_release(&pvec);
}
return hugepages << HPAGE_SHIFT;
}
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;
unsigned long bytes;
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;
bytes = huge_pages_needed(mapping, vma);
if (!is_hugepage_mem_enough(bytes))
return -ENOMEM;
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 = 0;
hugetlb_prefault_arch_hook(vma->vm_mm);
if (inode->i_size < len)
inode->i_size = len;
out:
up(&inode->i_sem);
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 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)
{
if (inode->i_data.nrpages)
truncate_hugepages(&inode->i_data, 0);
clear_inode(inode);
}
static void hugetlbfs_forget_inode(struct inode *inode)
{
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);
if (inode->i_data.nrpages)
truncate_hugepages(&inode->i_data, 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);
}
/*
* 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_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;
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)
{
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;
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);
/* 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 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);
}
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++;
}
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");