![Ken Chen](/assets/img/avatar_default.png)
__unmap_hugepage_range() is buggy that it does not preserve dirty state of huge_pte when unmapping hugepage range. It causes data corruption in the event of dop_caches being used by sys admin. For example, an application creates a hugetlb file, modify pages, then unmap it. While leaving the hugetlb file alive, comes along sys admin doing a "echo 3 > /proc/sys/vm/drop_caches". drop_pagecache_sb() will happily free all pages that aren't marked dirty if there are no active mapping. Later when application remaps the hugetlb file back and all data are gone, triggering catastrophic flip over on application. Not only that, the internal resv_huge_pages count will also get all messed up. Fix it up by marking page dirty appropriately. Signed-off-by: Ken Chen <kenchen@google.com> Cc: "Nish Aravamudan" <nish.aravamudan@gmail.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: <stable@kernel.org> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
838 lines
20 KiB
C
838 lines
20 KiB
C
/*
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* hugetlbpage-backed filesystem. Based on ramfs.
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*
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* William Irwin, 2002
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*
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* Copyright (C) 2002 Linus Torvalds.
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*/
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#include <linux/module.h>
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#include <linux/thread_info.h>
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#include <asm/current.h>
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#include <linux/sched.h> /* remove ASAP */
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/file.h>
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#include <linux/writeback.h>
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#include <linux/pagemap.h>
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#include <linux/highmem.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/capability.h>
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#include <linux/backing-dev.h>
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#include <linux/hugetlb.h>
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#include <linux/pagevec.h>
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#include <linux/quotaops.h>
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#include <linux/slab.h>
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#include <linux/dnotify.h>
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#include <linux/statfs.h>
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#include <linux/security.h>
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#include <asm/uaccess.h>
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/* some random number */
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#define HUGETLBFS_MAGIC 0x958458f6
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static struct super_operations hugetlbfs_ops;
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static const struct address_space_operations hugetlbfs_aops;
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const struct file_operations hugetlbfs_file_operations;
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static struct inode_operations hugetlbfs_dir_inode_operations;
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static struct inode_operations hugetlbfs_inode_operations;
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static struct backing_dev_info hugetlbfs_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
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};
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int sysctl_hugetlb_shm_group;
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static void huge_pagevec_release(struct pagevec *pvec)
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{
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int i;
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for (i = 0; i < pagevec_count(pvec); ++i)
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put_page(pvec->pages[i]);
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pagevec_reinit(pvec);
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}
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static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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loff_t len, vma_len;
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int ret;
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/*
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* vma alignment has already been checked by prepare_hugepage_range.
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* If you add any error returns here, do so after setting VM_HUGETLB,
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* so is_vm_hugetlb_page tests below unmap_region go the right way
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* when do_mmap_pgoff unwinds (may be important on powerpc and ia64).
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*/
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vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
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vma->vm_ops = &hugetlb_vm_ops;
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vma_len = (loff_t)(vma->vm_end - vma->vm_start);
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mutex_lock(&inode->i_mutex);
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file_accessed(file);
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ret = -ENOMEM;
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len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
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if (vma->vm_flags & VM_MAYSHARE &&
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hugetlb_reserve_pages(inode, vma->vm_pgoff >> (HPAGE_SHIFT-PAGE_SHIFT),
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len >> HPAGE_SHIFT))
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goto out;
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ret = 0;
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hugetlb_prefault_arch_hook(vma->vm_mm);
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if (vma->vm_flags & VM_WRITE && inode->i_size < len)
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inode->i_size = len;
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out:
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mutex_unlock(&inode->i_mutex);
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return ret;
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}
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/*
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* Called under down_write(mmap_sem).
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*/
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#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
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unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags);
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#else
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static unsigned long
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hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
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unsigned long len, unsigned long pgoff, unsigned long flags)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long start_addr;
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if (len & ~HPAGE_MASK)
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return -EINVAL;
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if (len > TASK_SIZE)
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return -ENOMEM;
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if (addr) {
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addr = ALIGN(addr, HPAGE_SIZE);
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vma = find_vma(mm, addr);
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if (TASK_SIZE - len >= addr &&
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(!vma || addr + len <= vma->vm_start))
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return addr;
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}
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start_addr = mm->free_area_cache;
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if (len <= mm->cached_hole_size)
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start_addr = TASK_UNMAPPED_BASE;
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full_search:
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addr = ALIGN(start_addr, HPAGE_SIZE);
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for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
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/* At this point: (!vma || addr < vma->vm_end). */
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if (TASK_SIZE - len < addr) {
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/*
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* Start a new search - just in case we missed
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* some holes.
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*/
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if (start_addr != TASK_UNMAPPED_BASE) {
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start_addr = TASK_UNMAPPED_BASE;
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goto full_search;
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}
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return -ENOMEM;
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}
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if (!vma || addr + len <= vma->vm_start)
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return addr;
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addr = ALIGN(vma->vm_end, HPAGE_SIZE);
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}
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}
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#endif
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/*
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* Read a page. Again trivial. If it didn't already exist
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* in the page cache, it is zero-filled.
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*/
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static int hugetlbfs_readpage(struct file *file, struct page * page)
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{
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unlock_page(page);
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return -EINVAL;
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}
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static int hugetlbfs_prepare_write(struct file *file,
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struct page *page, unsigned offset, unsigned to)
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{
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return -EINVAL;
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}
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static int hugetlbfs_commit_write(struct file *file,
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struct page *page, unsigned offset, unsigned to)
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{
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return -EINVAL;
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}
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static void truncate_huge_page(struct page *page)
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{
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cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
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ClearPageUptodate(page);
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remove_from_page_cache(page);
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put_page(page);
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}
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static void truncate_hugepages(struct inode *inode, loff_t lstart)
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{
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struct address_space *mapping = &inode->i_data;
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const pgoff_t start = lstart >> HPAGE_SHIFT;
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struct pagevec pvec;
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pgoff_t next;
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int i, freed = 0;
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pagevec_init(&pvec, 0);
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next = start;
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while (1) {
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if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
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if (next == start)
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break;
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next = start;
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continue;
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}
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for (i = 0; i < pagevec_count(&pvec); ++i) {
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struct page *page = pvec.pages[i];
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lock_page(page);
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if (page->index > next)
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next = page->index;
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++next;
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truncate_huge_page(page);
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unlock_page(page);
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hugetlb_put_quota(mapping);
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freed++;
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}
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huge_pagevec_release(&pvec);
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}
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BUG_ON(!lstart && mapping->nrpages);
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hugetlb_unreserve_pages(inode, start, freed);
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}
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static void hugetlbfs_delete_inode(struct inode *inode)
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{
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truncate_hugepages(inode, 0);
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clear_inode(inode);
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}
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static void hugetlbfs_forget_inode(struct inode *inode) __releases(inode_lock)
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{
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struct super_block *sb = inode->i_sb;
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if (!hlist_unhashed(&inode->i_hash)) {
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if (!(inode->i_state & (I_DIRTY|I_LOCK)))
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list_move(&inode->i_list, &inode_unused);
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inodes_stat.nr_unused++;
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if (!sb || (sb->s_flags & MS_ACTIVE)) {
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spin_unlock(&inode_lock);
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return;
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}
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inode->i_state |= I_WILL_FREE;
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spin_unlock(&inode_lock);
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/*
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* write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
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* in our backing_dev_info.
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*/
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write_inode_now(inode, 1);
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spin_lock(&inode_lock);
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inode->i_state &= ~I_WILL_FREE;
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inodes_stat.nr_unused--;
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hlist_del_init(&inode->i_hash);
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}
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list_del_init(&inode->i_list);
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list_del_init(&inode->i_sb_list);
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inode->i_state |= I_FREEING;
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inodes_stat.nr_inodes--;
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spin_unlock(&inode_lock);
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truncate_hugepages(inode, 0);
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clear_inode(inode);
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destroy_inode(inode);
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}
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static void hugetlbfs_drop_inode(struct inode *inode)
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{
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if (!inode->i_nlink)
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generic_delete_inode(inode);
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else
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hugetlbfs_forget_inode(inode);
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}
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static inline void
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hugetlb_vmtruncate_list(struct prio_tree_root *root, pgoff_t pgoff)
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{
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struct vm_area_struct *vma;
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struct prio_tree_iter iter;
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vma_prio_tree_foreach(vma, &iter, root, pgoff, ULONG_MAX) {
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unsigned long v_offset;
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/*
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* Can the expression below overflow on 32-bit arches?
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* No, because the prio_tree returns us only those vmas
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* which overlap the truncated area starting at pgoff,
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* and no vma on a 32-bit arch can span beyond the 4GB.
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*/
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if (vma->vm_pgoff < pgoff)
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v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
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else
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v_offset = 0;
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__unmap_hugepage_range(vma,
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vma->vm_start + v_offset, vma->vm_end);
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}
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}
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/*
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* Expanding truncates are not allowed.
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*/
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static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
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{
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pgoff_t pgoff;
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struct address_space *mapping = inode->i_mapping;
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if (offset > inode->i_size)
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return -EINVAL;
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BUG_ON(offset & ~HPAGE_MASK);
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pgoff = offset >> PAGE_SHIFT;
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inode->i_size = offset;
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spin_lock(&mapping->i_mmap_lock);
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if (!prio_tree_empty(&mapping->i_mmap))
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hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
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spin_unlock(&mapping->i_mmap_lock);
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truncate_hugepages(inode, offset);
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return 0;
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}
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static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
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{
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struct inode *inode = dentry->d_inode;
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int error;
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unsigned int ia_valid = attr->ia_valid;
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BUG_ON(!inode);
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error = inode_change_ok(inode, attr);
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if (error)
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goto out;
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if (ia_valid & ATTR_SIZE) {
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error = -EINVAL;
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if (!(attr->ia_size & ~HPAGE_MASK))
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error = hugetlb_vmtruncate(inode, attr->ia_size);
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if (error)
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goto out;
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attr->ia_valid &= ~ATTR_SIZE;
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}
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error = inode_setattr(inode, attr);
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out:
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return error;
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}
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static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
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gid_t gid, int mode, dev_t dev)
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{
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struct inode *inode;
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inode = new_inode(sb);
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if (inode) {
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struct hugetlbfs_inode_info *info;
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inode->i_mode = mode;
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inode->i_uid = uid;
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inode->i_gid = gid;
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inode->i_blocks = 0;
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inode->i_mapping->a_ops = &hugetlbfs_aops;
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inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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INIT_LIST_HEAD(&inode->i_mapping->private_list);
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info = HUGETLBFS_I(inode);
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mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
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switch (mode & S_IFMT) {
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default:
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init_special_inode(inode, mode, dev);
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break;
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case S_IFREG:
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inode->i_op = &hugetlbfs_inode_operations;
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inode->i_fop = &hugetlbfs_file_operations;
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break;
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case S_IFDIR:
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inode->i_op = &hugetlbfs_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inc_nlink(inode);
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break;
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case S_IFLNK:
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inode->i_op = &page_symlink_inode_operations;
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break;
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}
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}
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return inode;
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}
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/*
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* File creation. Allocate an inode, and we're done..
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*/
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static int hugetlbfs_mknod(struct inode *dir,
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struct dentry *dentry, int mode, dev_t dev)
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{
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struct inode *inode;
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int error = -ENOSPC;
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gid_t gid;
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if (dir->i_mode & S_ISGID) {
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gid = dir->i_gid;
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if (S_ISDIR(mode))
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mode |= S_ISGID;
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} else {
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gid = current->fsgid;
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}
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inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
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if (inode) {
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dir->i_ctime = dir->i_mtime = CURRENT_TIME;
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d_instantiate(dentry, inode);
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dget(dentry); /* Extra count - pin the dentry in core */
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error = 0;
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}
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return error;
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}
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static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
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{
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int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
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if (!retval)
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inc_nlink(dir);
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return retval;
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}
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static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
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{
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return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
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}
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static int hugetlbfs_symlink(struct inode *dir,
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struct dentry *dentry, const char *symname)
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{
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struct inode *inode;
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int error = -ENOSPC;
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gid_t gid;
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if (dir->i_mode & S_ISGID)
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gid = dir->i_gid;
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else
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gid = current->fsgid;
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inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
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gid, S_IFLNK|S_IRWXUGO, 0);
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if (inode) {
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int l = strlen(symname)+1;
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error = page_symlink(inode, symname, l);
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if (!error) {
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d_instantiate(dentry, inode);
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dget(dentry);
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} else
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iput(inode);
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}
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dir->i_ctime = dir->i_mtime = CURRENT_TIME;
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return error;
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}
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/*
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* mark the head page dirty
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*/
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static int hugetlbfs_set_page_dirty(struct page *page)
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{
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struct page *head = (struct page *)page_private(page);
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SetPageDirty(head);
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return 0;
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}
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static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
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buf->f_type = HUGETLBFS_MAGIC;
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buf->f_bsize = HPAGE_SIZE;
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if (sbinfo) {
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spin_lock(&sbinfo->stat_lock);
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/* If no limits set, just report 0 for max/free/used
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* blocks, like simple_statfs() */
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if (sbinfo->max_blocks >= 0) {
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buf->f_blocks = sbinfo->max_blocks;
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buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
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buf->f_files = sbinfo->max_inodes;
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buf->f_ffree = sbinfo->free_inodes;
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}
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spin_unlock(&sbinfo->stat_lock);
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}
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buf->f_namelen = NAME_MAX;
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return 0;
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}
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static void hugetlbfs_put_super(struct super_block *sb)
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{
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struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
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if (sbi) {
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sb->s_fs_info = NULL;
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kfree(sbi);
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}
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}
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|
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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 = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
|
|
if (unlikely(!p)) {
|
|
hugetlbfs_inc_free_inodes(sbinfo);
|
|
return NULL;
|
|
}
|
|
return &p->vfs_inode;
|
|
}
|
|
|
|
static void hugetlbfs_destroy_inode(struct inode *inode)
|
|
{
|
|
hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
|
|
mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
|
|
kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
|
|
}
|
|
|
|
static const struct address_space_operations hugetlbfs_aops = {
|
|
.readpage = hugetlbfs_readpage,
|
|
.prepare_write = hugetlbfs_prepare_write,
|
|
.commit_write = hugetlbfs_commit_write,
|
|
.set_page_dirty = hugetlbfs_set_page_dirty,
|
|
};
|
|
|
|
|
|
static void init_once(void *foo, struct kmem_cache *cachep, unsigned long flags)
|
|
{
|
|
struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
|
|
|
|
if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
|
|
SLAB_CTOR_CONSTRUCTOR)
|
|
inode_init_once(&ei->vfs_inode);
|
|
}
|
|
|
|
const struct file_operations hugetlbfs_file_operations = {
|
|
.mmap = hugetlbfs_file_mmap,
|
|
.fsync = simple_sync_file,
|
|
.get_unmapped_area = hugetlb_get_unmapped_area,
|
|
};
|
|
|
|
static struct inode_operations hugetlbfs_dir_inode_operations = {
|
|
.create = hugetlbfs_create,
|
|
.lookup = simple_lookup,
|
|
.link = simple_link,
|
|
.unlink = simple_unlink,
|
|
.symlink = hugetlbfs_symlink,
|
|
.mkdir = hugetlbfs_mkdir,
|
|
.rmdir = simple_rmdir,
|
|
.mknod = hugetlbfs_mknod,
|
|
.rename = simple_rename,
|
|
.setattr = hugetlbfs_setattr,
|
|
};
|
|
|
|
static struct inode_operations hugetlbfs_inode_operations = {
|
|
.setattr = hugetlbfs_setattr,
|
|
};
|
|
|
|
static struct super_operations hugetlbfs_ops = {
|
|
.alloc_inode = hugetlbfs_alloc_inode,
|
|
.destroy_inode = hugetlbfs_destroy_inode,
|
|
.statfs = hugetlbfs_statfs,
|
|
.delete_inode = hugetlbfs_delete_inode,
|
|
.drop_inode = hugetlbfs_drop_inode,
|
|
.put_super = hugetlbfs_put_super,
|
|
};
|
|
|
|
static int
|
|
hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
|
|
{
|
|
char *opt, *value, *rest;
|
|
|
|
if (!options)
|
|
return 0;
|
|
while ((opt = strsep(&options, ",")) != NULL) {
|
|
if (!*opt)
|
|
continue;
|
|
|
|
value = strchr(opt, '=');
|
|
if (!value || !*value)
|
|
return -EINVAL;
|
|
else
|
|
*value++ = '\0';
|
|
|
|
if (!strcmp(opt, "uid"))
|
|
pconfig->uid = simple_strtoul(value, &value, 0);
|
|
else if (!strcmp(opt, "gid"))
|
|
pconfig->gid = simple_strtoul(value, &value, 0);
|
|
else if (!strcmp(opt, "mode"))
|
|
pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
|
|
else if (!strcmp(opt, "size")) {
|
|
unsigned long long size = memparse(value, &rest);
|
|
if (*rest == '%') {
|
|
size <<= HPAGE_SHIFT;
|
|
size *= max_huge_pages;
|
|
do_div(size, 100);
|
|
rest++;
|
|
}
|
|
pconfig->nr_blocks = (size >> HPAGE_SHIFT);
|
|
value = rest;
|
|
} else if (!strcmp(opt,"nr_inodes")) {
|
|
pconfig->nr_inodes = memparse(value, &rest);
|
|
value = rest;
|
|
} else
|
|
return -EINVAL;
|
|
|
|
if (*value)
|
|
return -EINVAL;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
|
|
{
|
|
struct inode * inode;
|
|
struct dentry * root;
|
|
int ret;
|
|
struct hugetlbfs_config config;
|
|
struct hugetlbfs_sb_info *sbinfo;
|
|
|
|
config.nr_blocks = -1; /* No limit on size by default */
|
|
config.nr_inodes = -1; /* No limit on number of inodes by default */
|
|
config.uid = current->fsuid;
|
|
config.gid = current->fsgid;
|
|
config.mode = 0755;
|
|
ret = hugetlbfs_parse_options(data, &config);
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
|
|
if (!sbinfo)
|
|
return -ENOMEM;
|
|
sb->s_fs_info = sbinfo;
|
|
spin_lock_init(&sbinfo->stat_lock);
|
|
sbinfo->max_blocks = config.nr_blocks;
|
|
sbinfo->free_blocks = config.nr_blocks;
|
|
sbinfo->max_inodes = config.nr_inodes;
|
|
sbinfo->free_inodes = config.nr_inodes;
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
sb->s_blocksize = HPAGE_SIZE;
|
|
sb->s_blocksize_bits = HPAGE_SHIFT;
|
|
sb->s_magic = HUGETLBFS_MAGIC;
|
|
sb->s_op = &hugetlbfs_ops;
|
|
sb->s_time_gran = 1;
|
|
inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
|
|
S_IFDIR | config.mode, 0);
|
|
if (!inode)
|
|
goto out_free;
|
|
|
|
root = d_alloc_root(inode);
|
|
if (!root) {
|
|
iput(inode);
|
|
goto out_free;
|
|
}
|
|
sb->s_root = root;
|
|
return 0;
|
|
out_free:
|
|
kfree(sbinfo);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
int hugetlb_get_quota(struct address_space *mapping)
|
|
{
|
|
int ret = 0;
|
|
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
|
|
|
|
if (sbinfo->free_blocks > -1) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
if (sbinfo->free_blocks > 0)
|
|
sbinfo->free_blocks--;
|
|
else
|
|
ret = -ENOMEM;
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void hugetlb_put_quota(struct address_space *mapping)
|
|
{
|
|
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
|
|
|
|
if (sbinfo->free_blocks > -1) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
sbinfo->free_blocks++;
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
}
|
|
|
|
static int hugetlbfs_get_sb(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
|
|
{
|
|
return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super, mnt);
|
|
}
|
|
|
|
static struct file_system_type hugetlbfs_fs_type = {
|
|
.name = "hugetlbfs",
|
|
.get_sb = hugetlbfs_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
static struct vfsmount *hugetlbfs_vfsmount;
|
|
|
|
static int can_do_hugetlb_shm(void)
|
|
{
|
|
return likely(capable(CAP_IPC_LOCK) ||
|
|
in_group_p(sysctl_hugetlb_shm_group) ||
|
|
can_do_mlock());
|
|
}
|
|
|
|
struct file *hugetlb_zero_setup(size_t size)
|
|
{
|
|
int error = -ENOMEM;
|
|
struct file *file;
|
|
struct inode *inode;
|
|
struct dentry *dentry, *root;
|
|
struct qstr quick_string;
|
|
char buf[16];
|
|
static atomic_t counter;
|
|
|
|
if (!can_do_hugetlb_shm())
|
|
return ERR_PTR(-EPERM);
|
|
|
|
if (!user_shm_lock(size, current->user))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
root = hugetlbfs_vfsmount->mnt_root;
|
|
snprintf(buf, 16, "%u", atomic_inc_return(&counter));
|
|
quick_string.name = buf;
|
|
quick_string.len = strlen(quick_string.name);
|
|
quick_string.hash = 0;
|
|
dentry = d_alloc(root, &quick_string);
|
|
if (!dentry)
|
|
goto out_shm_unlock;
|
|
|
|
error = -ENFILE;
|
|
file = get_empty_filp();
|
|
if (!file)
|
|
goto out_dentry;
|
|
|
|
error = -ENOSPC;
|
|
inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
|
|
current->fsgid, S_IFREG | S_IRWXUGO, 0);
|
|
if (!inode)
|
|
goto out_file;
|
|
|
|
error = -ENOMEM;
|
|
if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
|
|
goto out_inode;
|
|
|
|
d_instantiate(dentry, inode);
|
|
inode->i_size = size;
|
|
inode->i_nlink = 0;
|
|
file->f_path.mnt = mntget(hugetlbfs_vfsmount);
|
|
file->f_path.dentry = dentry;
|
|
file->f_mapping = inode->i_mapping;
|
|
file->f_op = &hugetlbfs_file_operations;
|
|
file->f_mode = FMODE_WRITE | FMODE_READ;
|
|
return file;
|
|
|
|
out_inode:
|
|
iput(inode);
|
|
out_file:
|
|
put_filp(file);
|
|
out_dentry:
|
|
dput(dentry);
|
|
out_shm_unlock:
|
|
user_shm_unlock(size, current->user);
|
|
return ERR_PTR(error);
|
|
}
|
|
|
|
static int __init init_hugetlbfs_fs(void)
|
|
{
|
|
int error;
|
|
struct vfsmount *vfsmount;
|
|
|
|
hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
|
|
sizeof(struct hugetlbfs_inode_info),
|
|
0, 0, init_once, NULL);
|
|
if (hugetlbfs_inode_cachep == NULL)
|
|
return -ENOMEM;
|
|
|
|
error = register_filesystem(&hugetlbfs_fs_type);
|
|
if (error)
|
|
goto out;
|
|
|
|
vfsmount = kern_mount(&hugetlbfs_fs_type);
|
|
|
|
if (!IS_ERR(vfsmount)) {
|
|
hugetlbfs_vfsmount = vfsmount;
|
|
return 0;
|
|
}
|
|
|
|
error = PTR_ERR(vfsmount);
|
|
|
|
out:
|
|
if (error)
|
|
kmem_cache_destroy(hugetlbfs_inode_cachep);
|
|
return error;
|
|
}
|
|
|
|
static void __exit exit_hugetlbfs_fs(void)
|
|
{
|
|
kmem_cache_destroy(hugetlbfs_inode_cachep);
|
|
unregister_filesystem(&hugetlbfs_fs_type);
|
|
}
|
|
|
|
module_init(init_hugetlbfs_fs)
|
|
module_exit(exit_hugetlbfs_fs)
|
|
|
|
MODULE_LICENSE("GPL");
|