/*
* hugetlbpage-backed filesystem. Based on ramfs.
*
* Nadia Yvette Chambers, 2002
*
* Copyright (C) 2002 Linus Torvalds.
* License: GPL
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/thread_info.h>
#include <asm/current.h>
#include <linux/falloc.h>
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/file.h>
#include <linux/kernel.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/ctype.h>
#include <linux/backing-dev.h>
#include <linux/hugetlb.h>
#include <linux/pagevec.h>
#include <linux/fs_parser.h>
#include <linux/mman.h>
#include <linux/slab.h>
#include <linux/dnotify.h>
#include <linux/statfs.h>
#include <linux/security.h>
#include <linux/magic.h>
#include <linux/migrate.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
#include <linux/sched/mm.h>
static const struct address_space_operations hugetlbfs_aops;
static const struct file_operations hugetlbfs_file_operations;
static const struct inode_operations hugetlbfs_dir_inode_operations;
static const struct inode_operations hugetlbfs_inode_operations;
enum hugetlbfs_size_type { NO_SIZE, SIZE_STD, SIZE_PERCENT };
struct hugetlbfs_fs_context {
struct hstate *hstate;
unsigned long long max_size_opt;
unsigned long long min_size_opt;
long max_hpages;
long nr_inodes;
long min_hpages;
enum hugetlbfs_size_type max_val_type;
enum hugetlbfs_size_type min_val_type;
kuid_t uid;
kgid_t gid;
umode_t mode;
};
int sysctl_hugetlb_shm_group;
enum hugetlb_param {
Opt_gid,
Opt_min_size,
Opt_mode,
Opt_nr_inodes,
Opt_pagesize,
Opt_size,
Opt_uid,
};
static const struct fs_parameter_spec hugetlb_fs_parameters[] = {
fsparam_gid ("gid", Opt_gid),
fsparam_string("min_size", Opt_min_size),
fsparam_u32oct("mode", Opt_mode),
fsparam_string("nr_inodes", Opt_nr_inodes),
fsparam_string("pagesize", Opt_pagesize),
fsparam_string("size", Opt_size),
fsparam_uid ("uid", Opt_uid),
{}
};
/*
* Mask used when checking the page offset value passed in via system
* calls. This value will be converted to a loff_t which is signed.
* Therefore, we want to check the upper PAGE_SHIFT + 1 bits of the
* value. The extra bit (- 1 in the shift value) is to take the sign
* bit into account.
*/
#define PGOFF_LOFFT_MAX \
(((1UL << (PAGE_SHIFT + 1)) - 1) << (BITS_PER_LONG - (PAGE_SHIFT + 1)))
static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *inode = file_inode(file);
struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
loff_t len, vma_len;
int ret;
struct hstate *h = hstate_file(file);
vm_flags_t vm_flags;
/*
* vma address alignment (but not the pgoff 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 unwinds (may be important on powerpc
* and ia64).
*/
vm_flags_set(vma, VM_HUGETLB | VM_DONTEXPAND);
vma->vm_ops = &hugetlb_vm_ops;
ret = seal_check_write(info->seals, vma);
if (ret)
return ret;
/*
* page based offset in vm_pgoff could be sufficiently large to
* overflow a loff_t when converted to byte offset. This can
* only happen on architectures where sizeof(loff_t) ==
* sizeof(unsigned long). So, only check in those instances.
*/
if (sizeof(unsigned long) == sizeof(loff_t)) {
if (vma->vm_pgoff & PGOFF_LOFFT_MAX)
return -EINVAL;
}
/* must be huge page aligned */
if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
return -EINVAL;
vma_len = (loff_t)(vma->vm_end - vma->vm_start);
len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
/* check for overflow */
if (len < vma_len)
return -EINVAL;
inode_lock(inode);
file_accessed(file);
ret = -ENOMEM;
vm_flags = vma->vm_flags;
/*
* for SHM_HUGETLB, the pages are reserved in the shmget() call so skip
* reserving here. Note: only for SHM hugetlbfs file, the inode
* flag S_PRIVATE is set.
*/
if (inode->i_flags & S_PRIVATE)
vm_flags |= VM_NORESERVE;
if (!hugetlb_reserve_pages(inode,
vma->vm_pgoff >> huge_page_order(h),
len >> huge_page_shift(h), vma,
vm_flags))
goto out;
ret = 0;
if (vma->vm_flags & VM_WRITE && inode->i_size < len)
i_size_write(inode, len);
out:
inode_unlock(inode);
return ret;
}
/*
* Called under mmap_write_lock(mm).
*/
static unsigned long
hugetlb_get_unmapped_area_bottomup(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct hstate *h = hstate_file(file);
struct vm_unmapped_area_info info = {};
info.length = len;
info.low_limit = current->mm->mmap_base;
info.high_limit = arch_get_mmap_end(addr, len, flags);
info.align_mask = PAGE_MASK & ~huge_page_mask(h);
return vm_unmapped_area(&info);
}
static unsigned long
hugetlb_get_unmapped_area_topdown(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct hstate *h = hstate_file(file);
struct vm_unmapped_area_info info = {};
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
info.low_limit = PAGE_SIZE;
info.high_limit = arch_get_mmap_base(addr, current->mm->mmap_base);
info.align_mask = PAGE_MASK & ~huge_page_mask(h);
addr = vm_unmapped_area(&info);
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
if (unlikely(offset_in_page(addr))) {
VM_BUG_ON(addr != -ENOMEM);
info.flags = 0;
info.low_limit = current->mm->mmap_base;
info.high_limit = arch_get_mmap_end(addr, len, flags);
addr = vm_unmapped_area(&info);
}
return addr;
}
unsigned long
generic_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, *prev;
struct hstate *h = hstate_file(file);
const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags);
if (len & ~huge_page_mask(h))
return -EINVAL;
if (len > mmap_end - mmap_min_addr)
return -ENOMEM;
if (flags & MAP_FIXED) {
if (prepare_hugepage_range(file, addr, len))
return -EINVAL;
return addr;
}
if (addr) {
addr = ALIGN(addr, huge_page_size(h));
vma = find_vma_prev(mm, addr, &prev);
if (mmap_end - len >= addr && addr >= mmap_min_addr &&
(!vma || addr + len <= vm_start_gap(vma)) &&
(!prev || addr >= vm_end_gap(prev)))
return addr;
}
/*
* Use MMF_TOPDOWN flag as a hint to use topdown routine.
* If architectures have special needs, they should define their own
* version of hugetlb_get_unmapped_area.
*/
if (test_bit(MMF_TOPDOWN, &mm->flags))
return hugetlb_get_unmapped_area_topdown(file, addr, len,
pgoff, flags);
return hugetlb_get_unmapped_area_bottomup(file, addr, len,
pgoff, flags);
}
#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
static unsigned long
hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags)
{
return generic_hugetlb_get_unmapped_area(file, addr, len, pgoff, flags);
}
#endif
/*
* Someone wants to read @bytes from a HWPOISON hugetlb @page from @offset.
* Returns the maximum number of bytes one can read without touching the 1st raw
* HWPOISON subpage.
*
* The implementation borrows the iteration logic from copy_page_to_iter*.
*/
static size_t adjust_range_hwpoison(struct page *page, size_t offset, size_t bytes)
{
size_t n = 0;
size_t res = 0;
/* First subpage to start the loop. */
page = nth_page(page, offset / PAGE_SIZE);
offset %= PAGE_SIZE;
while (1) {
if (is_raw_hwpoison_page_in_hugepage(page))
break;
/* Safe to read n bytes without touching HWPOISON subpage. */
n = min(bytes, (size_t)PAGE_SIZE - offset);
res += n;
bytes -= n;
if (!bytes || !n)
break;
offset += n;
if (offset == PAGE_SIZE) {
page = nth_page(page, 1);
offset = 0;
}
}
return res;
}
/*
* Support for read() - Find the page attached to f_mapping and copy out the
* data. This provides functionality similar to filemap_read().
*/
static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
struct hstate *h = hstate_file(file);
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
unsigned long index = iocb->ki_pos >> huge_page_shift(h);
unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
unsigned long end_index;
loff_t isize;
ssize_t retval = 0;
while (iov_iter_count(to)) {
struct folio *folio;
size_t nr, copied, want;
/* nr is the maximum number of bytes to copy from this page */
nr = huge_page_size(h);
isize = i_size_read(inode);
if (!isize)
break;
end_index = (isize - 1) >> huge_page_shift(h);
if (index > end_index)
break;
if (index == end_index) {
nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
if (nr <= offset)
break;
}
nr = nr - offset;
/* Find the folio */
folio = filemap_lock_hugetlb_folio(h, mapping, index);
if (IS_ERR(folio)) {
/*
* We have a HOLE, zero out the user-buffer for the
* length of the hole or request.
*/
copied = iov_iter_zero(nr, to);
} else {
folio_unlock(folio);
if (!folio_test_hwpoison(folio))
want = nr;
else {
/*
* Adjust how many bytes safe to read without
* touching the 1st raw HWPOISON subpage after
* offset.
*/
want = adjust_range_hwpoison(&folio->page, offset, nr);
if (want == 0) {
folio_put(folio);
retval = -EIO;
break;
}
}
/*
* We have the folio, copy it to user space buffer.
*/
copied = copy_folio_to_iter(folio, offset, want, to);
folio_put(folio);
}
offset += copied;
retval += copied;
if (copied != nr && iov_iter_count(to)) {
if (!retval)
retval = -EFAULT;
break;
}
index += offset >> huge_page_shift(h);
offset &= ~huge_page_mask(h);
}
iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
return retval;
}
static int hugetlbfs_write_begin(struct file *file,
struct address_space *mapping,
loff_t pos, unsigned len,
struct folio **foliop, void **fsdata)
{
return -EINVAL;
}
static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct folio *folio, void *fsdata)
{
BUG();
return -EINVAL;
}
static void hugetlb_delete_from_page_cache(struct folio *folio)
{
folio_clear_dirty(folio);
folio_clear_uptodate(folio);
filemap_remove_folio(folio);
}
/*
* Called with i_mmap_rwsem held for inode based vma maps. This makes
* sure vma (and vm_mm) will not go away. We also hold the hugetlb fault
* mutex for the page in the mapping. So, we can not race with page being
* faulted into the vma.
*/
static bool hugetlb_vma_maps_page(struct vm_area_struct *vma,
unsigned long addr, struct page *page)
{
pte_t *ptep, pte;
ptep = hugetlb_walk(vma, addr, huge_page_size(hstate_vma(vma)));
if (!ptep)
return false;
pte = huge_ptep_get(vma->vm_mm, addr, ptep);
if (huge_pte_none(pte) || !pte_present(pte))
return false;
if (pte_page(pte) == page)
return true;
return false;
}
/*
* Can vma_offset_start/vma_offset_end overflow on 32-bit arches?
* No, because the interval 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.
*/
static unsigned long vma_offset_start(struct vm_area_struct *vma, pgoff_t start)
{
unsigned long offset = 0;
if (vma->vm_pgoff < start)
offset = (start - vma->vm_pgoff) << PAGE_SHIFT;
return vma->vm_start + offset;
}
static unsigned long vma_offset_end(struct vm_area_struct *vma, pgoff_t end)
{
unsigned long t_end;
if (!end)
return vma->vm_end;
t_end = ((end - vma->vm_pgoff) << PAGE_SHIFT) + vma->vm_start;
if (t_end > vma->vm_end)
t_end = vma->vm_end;
return t_end;
}
/*
* Called with hugetlb fault mutex held. Therefore, no more mappings to
* this folio can be created while executing the routine.
*/
static void hugetlb_unmap_file_folio(struct hstate *h,
struct address_space *mapping,
struct folio *folio, pgoff_t index)
{
struct rb_root_cached *root = &mapping->i_mmap;
struct hugetlb_vma_lock *vma_lock;
struct page *page = &folio->page;
struct vm_area_struct *vma;
unsigned long v_start;
unsigned long v_end;
pgoff_t start, end;
start = index * pages_per_huge_page(h);
end = (index + 1) * pages_per_huge_page(h);
i_mmap_lock_write(mapping);
retry:
vma_lock = NULL;
vma_interval_tree_foreach(vma, root, start, end - 1) {
v_start = vma_offset_start(vma, start);
v_end = vma_offset_end(vma, end);
if (!hugetlb_vma_maps_page(vma, v_start, page))
continue;
if (!hugetlb_vma_trylock_write(vma)) {
vma_lock = vma->vm_private_data;
/*
* If we can not get vma lock, we need to drop
* immap_sema and take locks in order. First,
* take a ref on the vma_lock structure so that
* we can be guaranteed it will not go away when
* dropping immap_sema.
*/
kref_get(&vma_lock->refs);
break;
}
unmap_hugepage_range(vma, v_start, v_end, NULL,
ZAP_FLAG_DROP_MARKER);
hugetlb_vma_unlock_write(vma);
}
i_mmap_unlock_write(mapping);
if (vma_lock) {
/*
* Wait on vma_lock. We know it is still valid as we have
* a reference. We must 'open code' vma locking as we do
* not know if vma_lock is still attached to vma.
*/
down_write(&vma_lock->rw_sema);
i_mmap_lock_write(mapping);
vma = vma_lock->vma;
if (!vma) {
/*
* If lock is no longer attached to vma, then just
* unlock, drop our reference and retry looking for
* other vmas.
*/
up_write(&vma_lock->rw_sema);
kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
goto retry;
}
/*
* vma_lock is still attached to vma. Check to see if vma
* still maps page and if so, unmap.
*/
v_start = vma_offset_start(vma, start);
v_end = vma_offset_end(vma, end);
if (hugetlb_vma_maps_page(vma, v_start, page))
unmap_hugepage_range(vma, v_start, v_end, NULL,
ZAP_FLAG_DROP_MARKER);
kref_put(&vma_lock->refs, hugetlb_vma_lock_release);
hugetlb_vma_unlock_write(vma);
goto retry;
}
}
static void
hugetlb_vmdelete_list(struct rb_root_cached *root, pgoff_t start, pgoff_t end,
zap_flags_t zap_flags)
{
struct vm_area_struct *vma;
/*
* end == 0 indicates that the entire range after start should be
* unmapped. Note, end is exclusive, whereas the interval tree takes
* an inclusive "last".
*/
vma_interval_tree_foreach(vma, root, start, end ? end - 1 : ULONG_MAX) {
unsigned long v_start;
unsigned long v_end;
if (!hugetlb_vma_trylock_write(vma))
continue;
v_start = vma_offset_start(vma, start);
v_end = vma_offset_end(vma, end);
unmap_hugepage_range(vma, v_start, v_end, NULL, zap_flags);
/*
* Note that vma lock only exists for shared/non-private
* vmas. Therefore, lock is not held when calling
* unmap_hugepage_range for private vmas.
*/
hugetlb_vma_unlock_write(vma);
}
}
/*
* Called with hugetlb fault mutex held.
* Returns true if page was actually removed, false otherwise.
*/
static bool remove_inode_single_folio(struct hstate *h, struct inode *inode,
struct address_space *mapping,
struct folio *folio, pgoff_t index,
bool truncate_op)
{
bool ret = false;
/*
* If folio is mapped, it was faulted in after being
* unmapped in caller. Unmap (again) while holding
* the fault mutex. The mutex will prevent faults
* until we finish removing the folio.
*/
if (unlikely(folio_mapped(folio)))
hugetlb_unmap_file_folio(h, mapping, folio, index);
folio_lock(folio);
/*
* We must remove the folio from page cache before removing
* the region/ reserve map (hugetlb_unreserve_pages). In
* rare out of memory conditions, removal of the region/reserve
* map could fail. Correspondingly, the subpool and global
* reserve usage count can need to be adjusted.
*/
VM_BUG_ON_FOLIO(folio_test_hugetlb_restore_reserve(folio), folio);
hugetlb_delete_from_page_cache(folio);
ret = true;
if (!truncate_op) {
if (unlikely(hugetlb_unreserve_pages(inode, index,
index + 1, 1)))
hugetlb_fix_reserve_counts(inode);
}
folio_unlock(folio);
return ret;
}
/*
* remove_inode_hugepages handles two distinct cases: truncation and hole
* punch. There are subtle differences in operation for each case.
*
* truncation is indicated by end of range being LLONG_MAX
* In this case, we first scan the range and release found pages.
* After releasing pages, hugetlb_unreserve_pages cleans up region/reserve
* maps and global counts. Page faults can race with truncation.
* During faults, hugetlb_no_page() checks i_size before page allocation,
* and again after obtaining page table lock. It will 'back out'
* allocations in the truncated range.
* hole punch is indicated if end is not LLONG_MAX
* In the hole punch case we scan the range and release found pages.
* Only when releasing a page is the associated region/reserve map
* deleted. The region/reserve map for ranges without associated
* pages are not modified. Page faults can race with hole punch.
* This is indicated if we find a mapped page.
* Note: If the passed end of range value is beyond the end of file, but
* not LLONG_MAX this routine still performs a hole punch operation.
*/
static void remove_inode_hugepages(struct inode *inode, loff_t lstart,
loff_t lend)
{
struct hstate *h = hstate_inode(inode);
struct address_space *mapping = &inode->i_data;
const pgoff_t end = lend >> PAGE_SHIFT;
struct folio_batch fbatch;
pgoff_t next, index;
int i, freed = 0;
bool truncate_op = (lend == LLONG_MAX);
folio_batch_init(&fbatch);
next = lstart >> PAGE_SHIFT;
while (filemap_get_folios(mapping, &next, end - 1, &fbatch)) {
for (i = 0; i < folio_batch_count(&fbatch); ++i) {
struct folio *folio = fbatch.folios[i];
u32 hash = 0;
index = folio->index >> huge_page_order(h);
hash = hugetlb_fault_mutex_hash(mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
/*
* Remove folio that was part of folio_batch.
*/
if (remove_inode_single_folio(h, inode, mapping, folio,
index, truncate_op))
freed++;
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
}
folio_batch_release(&fbatch);
cond_resched();
}
if (truncate_op)
(void)hugetlb_unreserve_pages(inode,
lstart >> huge_page_shift(h),
LONG_MAX, freed);
}
static void hugetlbfs_evict_inode(struct inode *inode)
{
struct resv_map *resv_map;
remove_inode_hugepages(inode, 0, LLONG_MAX);
/*
* Get the resv_map from the address space embedded in the inode.
* This is the address space which points to any resv_map allocated
* at inode creation time. If this is a device special inode,
* i_mapping may not point to the original address space.
*/
resv_map = (struct resv_map *)(&inode->i_data)->i_private_data;
/* Only regular and link inodes have associated reserve maps */
if (resv_map)
resv_map_release(&resv_map->refs);
clear_inode(inode);
}
static void hugetlb_vmtruncate(struct inode *inode, loff_t offset)
{
pgoff_t pgoff;
struct address_space *mapping = inode->i_mapping;
struct hstate *h = hstate_inode(inode);
BUG_ON(offset & ~huge_page_mask(h));
pgoff = offset >> PAGE_SHIFT;
i_size_write(inode, offset);
i_mmap_lock_write(mapping);
if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
hugetlb_vmdelete_list(&mapping->i_mmap, pgoff, 0,
ZAP_FLAG_DROP_MARKER);
i_mmap_unlock_write(mapping);
remove_inode_hugepages(inode, offset, LLONG_MAX);
}
static void hugetlbfs_zero_partial_page(struct hstate *h,
struct address_space *mapping,
loff_t start,
loff_t end)
{
pgoff_t idx = start >> huge_page_shift(h);
struct folio *folio;
folio = filemap_lock_hugetlb_folio(h, mapping, idx);
if (IS_ERR(folio))
return;
start = start & ~huge_page_mask(h);
end = end & ~huge_page_mask(h);
if (!end)
end = huge_page_size(h);
folio_zero_segment(folio, (size_t)start, (size_t)end);
folio_unlock(folio);
folio_put(folio);
}
static long hugetlbfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
{
struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
struct address_space *mapping = inode->i_mapping;
struct hstate *h = hstate_inode(inode);
loff_t hpage_size = huge_page_size(h);
loff_t hole_start, hole_end;
/*
* hole_start and hole_end indicate the full pages within the hole.
*/
hole_start = round_up(offset, hpage_size);
hole_end = round_down(offset + len, hpage_size);
inode_lock(inode);
/* protected by i_rwsem */
if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
inode_unlock(inode);
return -EPERM;
}
i_mmap_lock_write(mapping);
/* If range starts before first full page, zero partial page. */
if (offset < hole_start)
hugetlbfs_zero_partial_page(h, mapping,
offset, min(offset + len, hole_start));
/* Unmap users of full pages in the hole. */
if (hole_end > hole_start) {
if (!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))
hugetlb_vmdelete_list(&mapping->i_mmap,
hole_start >> PAGE_SHIFT,
hole_end >> PAGE_SHIFT, 0);
}
/* If range extends beyond last full page, zero partial page. */
if ((offset + len) > hole_end && (offset + len) > hole_start)
hugetlbfs_zero_partial_page(h, mapping,
hole_end, offset + len);
i_mmap_unlock_write(mapping);
/* Remove full pages from the file. */
if (hole_end > hole_start)
remove_inode_hugepages(inode, hole_start, hole_end);
inode_unlock(inode);
return 0;
}
static long hugetlbfs_fallocate(struct file *file, int mode, loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
struct address_space *mapping = inode->i_mapping;
struct hstate *h = hstate_inode(inode);
struct vm_area_struct pseudo_vma;
struct mm_struct *mm = current->mm;
loff_t hpage_size = huge_page_size(h);
unsigned long hpage_shift = huge_page_shift(h);
pgoff_t start, index, end;
int error;
u32 hash;
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return hugetlbfs_punch_hole(inode, offset, len);
/*
* Default preallocate case.
* For this range, start is rounded down and end is rounded up
* as well as being converted to page offsets.
*/
start = offset >> hpage_shift;
end = (offset + len + hpage_size - 1) >> hpage_shift;
inode_lock(inode);
/* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
error = inode_newsize_ok(inode, offset + len);
if (error)
goto out;
if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) {
error = -EPERM;
goto out;
}
/*
* Initialize a pseudo vma as this is required by the huge page
* allocation routines.
*/
vma_init(&pseudo_vma, mm);
vm_flags_init(&pseudo_vma, VM_HUGETLB | VM_MAYSHARE | VM_SHARED);
pseudo_vma.vm_file = file;
for (index = start; index < end; index++) {
/*
* This is supposed to be the vaddr where the page is being
* faulted in, but we have no vaddr here.
*/
struct folio *folio;
unsigned long addr;
cond_resched();
/*
* fallocate(2) manpage permits EINTR; we may have been
* interrupted because we are using up too much memory.
*/
if (signal_pending(current)) {
error = -EINTR;
break;
}
/* addr is the offset within the file (zero based) */
addr = index * hpage_size;
/* mutex taken here, fault path and hole punch */
hash = hugetlb_fault_mutex_hash(mapping, index);
mutex_lock(&hugetlb_fault_mutex_table[hash]);
/* See if already present in mapping to avoid alloc/free */
folio = filemap_get_folio(mapping, index << huge_page_order(h));
if (!IS_ERR(folio)) {
folio_put(folio);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
continue;
}
/*
* Allocate folio without setting the avoid_reserve argument.
* There certainly are no reserves associated with the
* pseudo_vma. However, there could be shared mappings with
* reserves for the file at the inode level. If we fallocate
* folios in these areas, we need to consume the reserves
* to keep reservation accounting consistent.
*/
folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0);
if (IS_ERR(folio)) {
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
error = PTR_ERR(folio);
goto out;
}
folio_zero_user(folio, ALIGN_DOWN(addr, hpage_size));
__folio_mark_uptodate(folio);
error = hugetlb_add_to_page_cache(folio, mapping, index);
if (unlikely(error)) {
restore_reserve_on_error(h, &pseudo_vma, addr, folio);
folio_put(folio);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
goto out;
}
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
folio_set_hugetlb_migratable(folio);
/*
* folio_unlock because locked by hugetlb_add_to_page_cache()
* folio_put() due to reference from alloc_hugetlb_folio()
*/
folio_unlock(folio);
folio_put(folio);
}
if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
i_size_write(inode, offset + len);
inode_set_ctime_current(inode);
out:
inode_unlock(inode);
return error;
}
static int hugetlbfs_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = d_inode(dentry);
struct hstate *h = hstate_inode(inode);
int error;
unsigned int ia_valid = attr->ia_valid;
struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
error = setattr_prepare(idmap, dentry, attr);
if (error)
return error;
if (ia_valid & ATTR_SIZE) {
loff_t oldsize = inode->i_size;
loff_t newsize = attr->ia_size;
if (newsize & ~huge_page_mask(h))
return -EINVAL;
/* protected by i_rwsem */
if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
(newsize > oldsize && (info->seals & F_SEAL_GROW)))
return -EPERM;
hugetlb_vmtruncate(inode, newsize);
}
setattr_copy(idmap, inode, attr);
mark_inode_dirty(inode);
return 0;
}
static struct inode *hugetlbfs_get_root(struct super_block *sb,
struct hugetlbfs_fs_context *ctx)
{
struct inode *inode;
inode = new_inode(sb);
if (inode) {
inode->i_ino = get_next_ino();
inode->i_mode = S_IFDIR | ctx->mode;
inode->i_uid = ctx->uid;
inode->i_gid = ctx->gid;
simple_inode_init_ts(inode);
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);
lockdep_annotate_inode_mutex_key(inode);
}
return inode;
}
/*
* Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
* be taken from reclaim -- unlike regular filesystems. This needs an
* annotation because huge_pmd_share() does an allocation under hugetlb's
* i_mmap_rwsem.
*/
static struct lock_class_key hugetlbfs_i_mmap_rwsem_key;
static struct inode *hugetlbfs_get_inode(struct super_block *sb,
struct mnt_idmap *idmap,
struct inode *dir,
umode_t mode, dev_t dev)
{
struct inode *inode;
struct resv_map *resv_map = NULL;
/*
* Reserve maps are only needed for inodes that can have associated
* page allocations.
*/
if (S_ISREG(mode) || S_ISLNK(mode)) {
resv_map = resv_map_alloc();
if (!resv_map)
return NULL;
}
inode = new_inode(sb);
if (inode) {
struct hugetlbfs_inode_info *info = HUGETLBFS_I(inode);
inode->i_ino = get_next_ino();
inode_init_owner(idmap, inode, dir, mode);
lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
&hugetlbfs_i_mmap_rwsem_key);
inode->i_mapping->a_ops = &hugetlbfs_aops;
simple_inode_init_ts(inode);
inode->i_mapping->i_private_data = resv_map;
info->seals = F_SEAL_SEAL;
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;
inode_nohighmem(inode);
break;
}
lockdep_annotate_inode_mutex_key(inode);
} else {
if (resv_map)
kref_put(&resv_map->refs, resv_map_release);
}
return inode;
}
/*
* File creation. Allocate an inode, and we're done..
*/
static int hugetlbfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t dev)
{
struct inode *inode;
inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, dev);
if (!inode)
return -ENOSPC;
inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
d_instantiate(dentry, inode);
dget(dentry);/* Extra count - pin the dentry in core */
return 0;
}
static int hugetlbfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
int retval = hugetlbfs_mknod(idmap, dir, dentry,
mode | S_IFDIR, 0);
if (!retval)
inc_nlink(dir);
return retval;
}
static int hugetlbfs_create(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *dentry,
umode_t mode, bool excl)
{
return hugetlbfs_mknod(idmap, dir, dentry, mode | S_IFREG, 0);
}
static int hugetlbfs_tmpfile(struct mnt_idmap *idmap,
struct inode *dir, struct file *file,
umode_t mode)
{
struct inode *inode;
inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode | S_IFREG, 0);
if (!inode)
return -ENOSPC;
inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
d_tmpfile(file, inode);
return finish_open_simple(file, 0);
}
static int hugetlbfs_symlink(struct mnt_idmap *idmap,
struct inode *dir, struct dentry *dentry,
const char *symname)
{
const umode_t mode = S_IFLNK|S_IRWXUGO;
struct inode *inode;
int error = -ENOSPC;
inode = hugetlbfs_get_inode(dir->i_sb, idmap, dir, mode, 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);
}
inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
return error;
}
#ifdef CONFIG_MIGRATION
static int hugetlbfs_migrate_folio(struct address_space *mapping,
struct folio *dst, struct folio *src,
enum migrate_mode mode)
{
int rc;
rc = migrate_huge_page_move_mapping(mapping, dst, src);
if (rc != MIGRATEPAGE_SUCCESS)
return rc;
if (hugetlb_folio_subpool(src)) {
hugetlb_set_folio_subpool(dst,
hugetlb_folio_subpool(src));
hugetlb_set_folio_subpool(src, NULL);
}
folio_migrate_flags(dst, src);
return MIGRATEPAGE_SUCCESS;
}
#else
#define hugetlbfs_migrate_folio NULL
#endif
static int hugetlbfs_error_remove_folio(struct address_space *mapping,
struct folio *folio)
{
return 0;
}
/*
* Display the mount options in /proc/mounts.
*/
static int hugetlbfs_show_options(struct seq_file *m, struct dentry *root)
{
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(root->d_sb);
struct hugepage_subpool *spool = sbinfo->spool;
unsigned long hpage_size = huge_page_size(sbinfo->hstate);
unsigned hpage_shift = huge_page_shift(sbinfo->hstate);
char mod;
if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
seq_printf(m, ",uid=%u",
from_kuid_munged(&init_user_ns, sbinfo->uid));
if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
seq_printf(m, ",gid=%u",
from_kgid_munged(&init_user_ns, sbinfo->gid));
if (sbinfo->mode != 0755)
seq_printf(m, ",mode=%o", sbinfo->mode);
if (sbinfo->max_inodes != -1)
seq_printf(m, ",nr_inodes=%lu", sbinfo->max_inodes);
hpage_size /= 1024;
mod = 'K';
if (hpage_size >= 1024) {
hpage_size /= 1024;
mod = 'M';
}
seq_printf(m, ",pagesize=%lu%c", hpage_size, mod);
if (spool) {
if (spool->max_hpages != -1)
seq_printf(m, ",size=%llu",
(unsigned long long)spool->max_hpages << hpage_shift);
if (spool->min_hpages != -1)
seq_printf(m, ",min_size=%llu",
(unsigned long long)spool->min_hpages << hpage_shift);
}
return 0;
}
static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
struct hstate *h = hstate_inode(d_inode(dentry));
u64 id = huge_encode_dev(dentry->d_sb->s_dev);
buf->f_fsid = u64_to_fsid(id);
buf->f_type = HUGETLBFS_MAGIC;
buf->f_bsize = huge_page_size(h);
if (sbinfo) {
spin_lock(&sbinfo->stat_lock);
/* If no limits set, just report 0 or -1 for max/free/used
* blocks, like simple_statfs() */
if (sbinfo->spool) {
long free_pages;
spin_lock_irq(&sbinfo->spool->lock);
buf->f_blocks = sbinfo->spool->max_hpages;
free_pages = sbinfo->spool->max_hpages
- sbinfo->spool->used_hpages;
buf->f_bavail = buf->f_bfree = free_pages;
spin_unlock_irq(&sbinfo->spool->lock);
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;
if (sbi->spool)
hugepage_put_subpool(sbi->spool);
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 struct kmem_cache *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 = alloc_inode_sb(sb, hugetlbfs_inode_cachep, GFP_KERNEL);
if (unlikely(!p)) {
hugetlbfs_inc_free_inodes(sbinfo);
return NULL;
}
return &p->vfs_inode;
}
static void hugetlbfs_free_inode(struct inode *inode)
{
kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
}
static void hugetlbfs_destroy_inode(struct inode *inode)
{
hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
}
static const struct address_space_operations hugetlbfs_aops = {
.write_begin = hugetlbfs_write_begin,
.write_end = hugetlbfs_write_end,
.dirty_folio = noop_dirty_folio,
.migrate_folio = hugetlbfs_migrate_folio,
.error_remove_folio = hugetlbfs_error_remove_folio,
};
static void init_once(void *foo)
{
struct hugetlbfs_inode_info *ei = foo;
inode_init_once(&ei->vfs_inode);
}
static const struct file_operations hugetlbfs_file_operations = {
.read_iter = hugetlbfs_read_iter,
.mmap = hugetlbfs_file_mmap,
.fsync = noop_fsync,
.get_unmapped_area = hugetlb_get_unmapped_area,
.llseek = default_llseek,
.fallocate = hugetlbfs_fallocate,
.fop_flags = FOP_HUGE_PAGES,
};
static const 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,
.tmpfile = hugetlbfs_tmpfile,
};
static const struct inode_operations hugetlbfs_inode_operations = {
.setattr = hugetlbfs_setattr,
};
static const struct super_operations hugetlbfs_ops = {
.alloc_inode = hugetlbfs_alloc_inode,
.free_inode = hugetlbfs_free_inode,
.destroy_inode = hugetlbfs_destroy_inode,
.evict_inode = hugetlbfs_evict_inode,
.statfs = hugetlbfs_statfs,
.put_super = hugetlbfs_put_super,
.show_options = hugetlbfs_show_options,
};
/*
* Convert size option passed from command line to number of huge pages
* in the pool specified by hstate. Size option could be in bytes
* (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
*/
static long
hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
enum hugetlbfs_size_type val_type)
{
if (val_type == NO_SIZE)
return -1;
if (val_type == SIZE_PERCENT) {
size_opt <<= huge_page_shift(h);
size_opt *= h->max_huge_pages;
do_div(size_opt, 100);
}
size_opt >>= huge_page_shift(h);
return size_opt;
}
/*
* Parse one mount parameter.
*/
static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct hugetlbfs_fs_context *ctx = fc->fs_private;
struct fs_parse_result result;
struct hstate *h;
char *rest;
unsigned long ps;
int opt;
opt = fs_parse(fc, hugetlb_fs_parameters, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_uid:
ctx->uid = result.uid;
return 0;
case Opt_gid:
ctx->gid = result.gid;
return 0;
case Opt_mode:
ctx->mode = result.uint_32 & 01777U;
return 0;
case Opt_size:
/* memparse() will accept a K/M/G without a digit */
if (!param->string || !isdigit(param->string[0]))
goto bad_val;
ctx->max_size_opt = memparse(param->string, &rest);
ctx->max_val_type = SIZE_STD;
if (*rest == '%')
ctx->max_val_type = SIZE_PERCENT;
return 0;
case Opt_nr_inodes:
/* memparse() will accept a K/M/G without a digit */
if (!param->string || !isdigit(param->string[0]))
goto bad_val;
ctx->nr_inodes = memparse(param->string, &rest);
return 0;
case Opt_pagesize:
ps = memparse(param->string, &rest);
h = size_to_hstate(ps);
if (!h) {
pr_err("Unsupported page size %lu MB\n", ps / SZ_1M);
return -EINVAL;
}
ctx->hstate = h;
return 0;
case Opt_min_size:
/* memparse() will accept a K/M/G without a digit */
if (!param->string || !isdigit(param->string[0]))
goto bad_val;
ctx->min_size_opt = memparse(param->string, &rest);
ctx->min_val_type = SIZE_STD;
if (*rest == '%')
ctx->min_val_type = SIZE_PERCENT;
return 0;
default:
return -EINVAL;
}
bad_val:
return invalfc(fc, "Bad value '%s' for mount option '%s'\n",
param->string, param->key);
}
/*
* Validate the parsed options.
*/
static int hugetlbfs_validate(struct fs_context *fc)
{
struct hugetlbfs_fs_context *ctx = fc->fs_private;
/*
* Use huge page pool size (in hstate) to convert the size
* options to number of huge pages. If NO_SIZE, -1 is returned.
*/
ctx->max_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
ctx->max_size_opt,
ctx->max_val_type);
ctx->min_hpages = hugetlbfs_size_to_hpages(ctx->hstate,
ctx->min_size_opt,
ctx->min_val_type);
/*
* If max_size was specified, then min_size must be smaller
*/
if (ctx->max_val_type > NO_SIZE &&
ctx->min_hpages > ctx->max_hpages) {
pr_err("Minimum size can not be greater than maximum size\n");
return -EINVAL;
}
return 0;
}
static int
hugetlbfs_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct hugetlbfs_fs_context *ctx = fc->fs_private;
struct hugetlbfs_sb_info *sbinfo;
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->hstate = ctx->hstate;
sbinfo->max_inodes = ctx->nr_inodes;
sbinfo->free_inodes = ctx->nr_inodes;
sbinfo->spool = NULL;
sbinfo->uid = ctx->uid;
sbinfo->gid = ctx->gid;
sbinfo->mode = ctx->mode;
/*
* Allocate and initialize subpool if maximum or minimum size is
* specified. Any needed reservations (for minimum size) are taken
* when the subpool is created.
*/
if (ctx->max_hpages != -1 || ctx->min_hpages != -1) {
sbinfo->spool = hugepage_new_subpool(ctx->hstate,
ctx->max_hpages,
ctx->min_hpages);
if (!sbinfo->spool)
goto out_free;
}
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_blocksize = huge_page_size(ctx->hstate);
sb->s_blocksize_bits = huge_page_shift(ctx->hstate);
sb->s_magic = HUGETLBFS_MAGIC;
sb->s_op = &hugetlbfs_ops;
sb->s_time_gran = 1;
/*
* Due to the special and limited functionality of hugetlbfs, it does
* not work well as a stacking filesystem.
*/
sb->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
sb->s_root = d_make_root(hugetlbfs_get_root(sb, ctx));
if (!sb->s_root)
goto out_free;
return 0;
out_free:
kfree(sbinfo->spool);
kfree(sbinfo);
return -ENOMEM;
}
static int hugetlbfs_get_tree(struct fs_context *fc)
{
int err = hugetlbfs_validate(fc);
if (err)
return err;
return get_tree_nodev(fc, hugetlbfs_fill_super);
}
static void hugetlbfs_fs_context_free(struct fs_context *fc)
{
kfree(fc->fs_private);
}
static const struct fs_context_operations hugetlbfs_fs_context_ops = {
.free = hugetlbfs_fs_context_free,
.parse_param = hugetlbfs_parse_param,
.get_tree = hugetlbfs_get_tree,
};
static int hugetlbfs_init_fs_context(struct fs_context *fc)
{
struct hugetlbfs_fs_context *ctx;
ctx = kzalloc(sizeof(struct hugetlbfs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->max_hpages = -1; /* No limit on size by default */
ctx->nr_inodes = -1; /* No limit on number of inodes by default */
ctx->uid = current_fsuid();
ctx->gid = current_fsgid();
ctx->mode = 0755;
ctx->hstate = &default_hstate;
ctx->min_hpages = -1; /* No default minimum size */
ctx->max_val_type = NO_SIZE;
ctx->min_val_type = NO_SIZE;
fc->fs_private = ctx;
fc->ops = &hugetlbfs_fs_context_ops;
return 0;
}
static struct file_system_type hugetlbfs_fs_type = {
.name = "hugetlbfs",
.init_fs_context = hugetlbfs_init_fs_context,
.parameters = hugetlb_fs_parameters,
.kill_sb = kill_litter_super,
.fs_flags = FS_ALLOW_IDMAP,
};
static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
static int can_do_hugetlb_shm(void)
{
kgid_t shm_group;
shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
}
static int get_hstate_idx(int page_size_log)
{
struct hstate *h = hstate_sizelog(page_size_log);
if (!h)
return -1;
return hstate_index(h);
}
/*
* Note that size should be aligned to proper hugepage size in caller side,
* otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
*/
struct file *hugetlb_file_setup(const char *name, size_t size,
vm_flags_t acctflag, int creat_flags,
int page_size_log)
{
struct inode *inode;
struct vfsmount *mnt;
int hstate_idx;
struct file *file;
hstate_idx = get_hstate_idx(page_size_log);
if (hstate_idx < 0)
return ERR_PTR(-ENODEV);
mnt = hugetlbfs_vfsmount[hstate_idx];
if (!mnt)
return ERR_PTR(-ENOENT);
if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
struct ucounts *ucounts = current_ucounts();
if (user_shm_lock(size, ucounts)) {
pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
current->comm, current->pid);
user_shm_unlock(size, ucounts);
}
return ERR_PTR(-EPERM);
}
file = ERR_PTR(-ENOSPC);
/* hugetlbfs_vfsmount[] mounts do not use idmapped mounts. */
inode = hugetlbfs_get_inode(mnt->mnt_sb, &nop_mnt_idmap, NULL,
S_IFREG | S_IRWXUGO, 0);
if (!inode)
goto out;
if (creat_flags == HUGETLB_SHMFS_INODE)
inode->i_flags |= S_PRIVATE;
inode->i_size = size;
clear_nlink(inode);
if (!hugetlb_reserve_pages(inode, 0,
size >> huge_page_shift(hstate_inode(inode)), NULL,
acctflag))
file = ERR_PTR(-ENOMEM);
else
file = alloc_file_pseudo(inode, mnt, name, O_RDWR,
&hugetlbfs_file_operations);
if (!IS_ERR(file))
return file;
iput(inode);
out:
return file;
}
static struct vfsmount *__init mount_one_hugetlbfs(struct hstate *h)
{
struct fs_context *fc;
struct vfsmount *mnt;
fc = fs_context_for_mount(&hugetlbfs_fs_type, SB_KERNMOUNT);
if (IS_ERR(fc)) {
mnt = ERR_CAST(fc);
} else {
struct hugetlbfs_fs_context *ctx = fc->fs_private;
ctx->hstate = h;
mnt = fc_mount(fc);
put_fs_context(fc);
}
if (IS_ERR(mnt))
pr_err("Cannot mount internal hugetlbfs for page size %luK",
huge_page_size(h) / SZ_1K);
return mnt;
}
static int __init init_hugetlbfs_fs(void)
{
struct vfsmount *mnt;
struct hstate *h;
int error;
int i;
if (!hugepages_supported()) {
pr_info("disabling because there are no supported hugepage sizes\n");
return -ENOTSUPP;
}
error = -ENOMEM;
hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
sizeof(struct hugetlbfs_inode_info),
0, SLAB_ACCOUNT, init_once);
if (hugetlbfs_inode_cachep == NULL)
goto out;
error = register_filesystem(&hugetlbfs_fs_type);
if (error)
goto out_free;
/* default hstate mount is required */
mnt = mount_one_hugetlbfs(&default_hstate);
if (IS_ERR(mnt)) {
error = PTR_ERR(mnt);
goto out_unreg;
}
hugetlbfs_vfsmount[default_hstate_idx] = mnt;
/* other hstates are optional */
i = 0;
for_each_hstate(h) {
if (i == default_hstate_idx) {
i++;
continue;
}
mnt = mount_one_hugetlbfs(h);
if (IS_ERR(mnt))
hugetlbfs_vfsmount[i] = NULL;
else
hugetlbfs_vfsmount[i] = mnt;
i++;
}
return 0;
out_unreg:
(void)unregister_filesystem(&hugetlbfs_fs_type);
out_free:
kmem_cache_destroy(hugetlbfs_inode_cachep);
out:
return error;
}
fs_initcall(init_hugetlbfs_fs)
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