diff options
Diffstat (limited to 'fs/hugetlbfs')
| -rw-r--r-- | fs/hugetlbfs/Makefile | 8 | ||||
| -rw-r--r-- | fs/hugetlbfs/inode.c | 1745 |
2 files changed, 1753 insertions, 0 deletions
diff --git a/fs/hugetlbfs/Makefile b/fs/hugetlbfs/Makefile new file mode 100644 index 0000000000..d876ecfbe6 --- /dev/null +++ b/fs/hugetlbfs/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Makefile for the linux ramfs routines. +# + +obj-$(CONFIG_HUGETLBFS) += hugetlbfs.o + +hugetlbfs-objs := inode.o diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c new file mode 100644 index 0000000000..60fce26ff9 --- /dev/null +++ b/fs/hugetlbfs/inode.c @@ -0,0 +1,1745 @@ +/* + * 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; +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_u32 ("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_u32 ("uid", Opt_uid), + {} +}; + +#ifdef CONFIG_NUMA +static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, + struct inode *inode, pgoff_t index) +{ + vma->vm_policy = mpol_shared_policy_lookup(&HUGETLBFS_I(inode)->policy, + index); +} + +static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) +{ + mpol_cond_put(vma->vm_policy); +} +#else +static inline void hugetlb_set_vma_policy(struct vm_area_struct *vma, + struct inode *inode, pgoff_t index) +{ +} + +static inline void hugetlb_drop_vma_policy(struct vm_area_struct *vma) +{ +} +#endif + +/* + * 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); + + /* + * 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_future_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; + if (!hugetlb_reserve_pages(inode, + vma->vm_pgoff >> huge_page_order(h), + len >> huge_page_shift(h), vma, + 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.flags = 0; + 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); + info.align_offset = 0; + 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); + info.align_offset = 0; + 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; + 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 > TASK_SIZE) + 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(mm, addr); + if (mmap_end - len >= addr && + (!vma || addr + len <= vm_start_gap(vma))) + return addr; + } + + /* + * Use mm->get_unmapped_area value as a hint to use topdown routine. + * If architectures have special needs, they should define their own + * version of hugetlb_get_unmapped_area. + */ + if (mm->get_unmapped_area == arch_get_unmapped_area_topdown) + 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 page *page; + 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 page */ + page = find_lock_page(mapping, index); + if (unlikely(page == NULL)) { + /* + * We have a HOLE, zero out the user-buffer for the + * length of the hole or request. + */ + copied = iov_iter_zero(nr, to); + } else { + unlock_page(page); + + if (!PageHWPoison(page)) + want = nr; + else { + /* + * Adjust how many bytes safe to read without + * touching the 1st raw HWPOISON subpage after + * offset. + */ + want = adjust_range_hwpoison(page, offset, nr); + if (want == 0) { + put_page(page); + retval = -EIO; + break; + } + } + + /* + * We have the page, copy it to user space buffer. + */ + copied = copy_page_to_iter(page, offset, want, to); + put_page(page); + } + 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 page **pagep, void **fsdata) +{ + return -EINVAL; +} + +static int hugetlbfs_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, 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(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 start = lstart >> huge_page_shift(h); + const pgoff_t end = lend >> huge_page_shift(h); + struct folio_batch fbatch; + pgoff_t next, index; + int i, freed = 0; + bool truncate_op = (lend == LLONG_MAX); + + folio_batch_init(&fbatch); + next = start; + 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; + 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, start, 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)->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_folio(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. If NUMA is configured, use page index + * as input to create an allocation policy. + */ + 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); + 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. + */ + hugetlb_set_vma_policy(&pseudo_vma, inode, index); + folio = alloc_hugetlb_folio(&pseudo_vma, addr, 0); + hugetlb_drop_vma_policy(&pseudo_vma); + if (IS_ERR(folio)) { + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + error = PTR_ERR(folio); + goto out; + } + clear_huge_page(&folio->page, addr, pages_per_huge_page(h)); + __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(&nop_mnt_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(&nop_mnt_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; + inode->i_atime = inode->i_mtime = inode_set_ctime_current(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 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(&nop_mnt_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; + inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode); + inode->i_mapping->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, dir, mode, dev); + if (!inode) + return -ENOSPC; + dir->i_mtime = 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(&nop_mnt_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(&nop_mnt_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, dir, mode | S_IFREG, 0); + if (!inode) + return -ENOSPC; + dir->i_mtime = 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) +{ + struct inode *inode; + int error = -ENOSPC; + + inode = hugetlbfs_get_inode(dir->i_sb, dir, 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_mtime = 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); + } + + if (mode != MIGRATE_SYNC_NO_COPY) + folio_migrate_copy(dst, src); + else + folio_migrate_flags(dst, src); + + return MIGRATEPAGE_SUCCESS; +} +#else +#define hugetlbfs_migrate_folio NULL +#endif + +static int hugetlbfs_error_remove_page(struct address_space *mapping, + struct page *page) +{ + 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)); + + 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; + } + + /* + * Any time after allocation, hugetlbfs_destroy_inode can be called + * for the inode. mpol_free_shared_policy is unconditionally called + * as part of hugetlbfs_destroy_inode. So, initialize policy here + * in case of a quick call to destroy. + * + * Note that the policy is initialized even if we are creating a + * private inode. This simplifies hugetlbfs_destroy_inode. + */ + mpol_shared_policy_init(&p->policy, 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)); + mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy); +} + +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_page = hugetlbfs_error_remove_page, +}; + + +static void init_once(void *foo) +{ + struct hugetlbfs_inode_info *ei = foo; + + inode_init_once(&ei->vfs_inode); +} + +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, +}; + +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; + 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 = make_kuid(current_user_ns(), result.uint_32); + if (!uid_valid(ctx->uid)) + goto bad_val; + return 0; + + case Opt_gid: + ctx->gid = make_kgid(current_user_ns(), result.uint_32); + if (!gid_valid(ctx->gid)) + goto bad_val; + 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); + ctx->hstate = size_to_hstate(ps); + if (!ctx->hstate) { + pr_err("Unsupported page size %lu MB\n", ps / SZ_1M); + return -EINVAL; + } + 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, +}; + +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); + inode = hugetlbfs_get_inode(mnt->mnt_sb, 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) |