![Dave Hansen](/assets/img/avatar_default.png)
Why do we need r/o bind mounts? This feature allows a read-only view into a read-write filesystem. In the process of doing that, it also provides infrastructure for keeping track of the number of writers to any given mount. This has a number of uses. It allows chroots to have parts of filesystems writable. It will be useful for containers in the future because users may have root inside a container, but should not be allowed to write to somefilesystems. This also replaces patches that vserver has had out of the tree for several years. It allows security enhancement by making sure that parts of your filesystem read-only (such as when you don't trust your FTP server), when you don't want to have entire new filesystems mounted, or when you want atime selectively updated. I've been using the following script to test that the feature is working as desired. It takes a directory and makes a regular bind and a r/o bind mount of it. It then performs some normal filesystem operations on the three directories, including ones that are expected to fail, like creating a file on the r/o mount. This patch: Some filesystems forego the vfs and may_open() and create their own 'struct file's. This patch creates a couple of helper functions which can be used by these filesystems, and will provide a unified place which the r/o bind mount code may patch. Also, rename an existing, static-scope init_file() to a less generic name. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1015 lines
23 KiB
C
1015 lines
23 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/kernel.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/ctype.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/parser.h>
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#include <linux/mman.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 const 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 const struct inode_operations hugetlbfs_dir_inode_operations;
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static const 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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enum {
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Opt_size, Opt_nr_inodes,
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Opt_mode, Opt_uid, Opt_gid,
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Opt_err,
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};
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static match_table_t tokens = {
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{Opt_size, "size=%s"},
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{Opt_nr_inodes, "nr_inodes=%s"},
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{Opt_mode, "mode=%o"},
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{Opt_uid, "uid=%u"},
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{Opt_gid, "gid=%u"},
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{Opt_err, NULL},
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};
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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 address alignment (but not the pgoff alignment) has
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* already been checked by prepare_hugepage_range. If you add
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* any error returns here, do so after setting VM_HUGETLB, so
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* is_vm_hugetlb_page tests below unmap_region go the right
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* way when do_mmap_pgoff unwinds (may be important on powerpc
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* 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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if (vma->vm_pgoff & ~(HPAGE_MASK >> PAGE_SHIFT))
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return -EINVAL;
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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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#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
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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 (flags & MAP_FIXED) {
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if (prepare_hugepage_range(addr, len))
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return -EINVAL;
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return addr;
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}
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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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static int
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hugetlbfs_read_actor(struct page *page, unsigned long offset,
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char __user *buf, unsigned long count,
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unsigned long size)
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{
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char *kaddr;
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unsigned long left, copied = 0;
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int i, chunksize;
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if (size > count)
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size = count;
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/* Find which 4k chunk and offset with in that chunk */
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i = offset >> PAGE_CACHE_SHIFT;
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offset = offset & ~PAGE_CACHE_MASK;
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while (size) {
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chunksize = PAGE_CACHE_SIZE;
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if (offset)
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chunksize -= offset;
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if (chunksize > size)
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chunksize = size;
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kaddr = kmap(&page[i]);
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left = __copy_to_user(buf, kaddr + offset, chunksize);
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kunmap(&page[i]);
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if (left) {
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copied += (chunksize - left);
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break;
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}
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offset = 0;
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size -= chunksize;
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buf += chunksize;
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copied += chunksize;
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i++;
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}
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return copied ? copied : -EFAULT;
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}
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/*
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* Support for read() - Find the page attached to f_mapping and copy out the
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* data. Its *very* similar to do_generic_mapping_read(), we can't use that
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* since it has PAGE_CACHE_SIZE assumptions.
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*/
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static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
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size_t len, loff_t *ppos)
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{
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struct address_space *mapping = filp->f_mapping;
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struct inode *inode = mapping->host;
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unsigned long index = *ppos >> HPAGE_SHIFT;
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unsigned long offset = *ppos & ~HPAGE_MASK;
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unsigned long end_index;
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loff_t isize;
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ssize_t retval = 0;
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mutex_lock(&inode->i_mutex);
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/* validate length */
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if (len == 0)
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goto out;
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isize = i_size_read(inode);
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if (!isize)
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goto out;
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end_index = (isize - 1) >> HPAGE_SHIFT;
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for (;;) {
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struct page *page;
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int nr, ret;
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/* nr is the maximum number of bytes to copy from this page */
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nr = HPAGE_SIZE;
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if (index >= end_index) {
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if (index > end_index)
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goto out;
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nr = ((isize - 1) & ~HPAGE_MASK) + 1;
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if (nr <= offset) {
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goto out;
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}
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}
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nr = nr - offset;
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/* Find the page */
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page = find_get_page(mapping, index);
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if (unlikely(page == NULL)) {
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/*
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* We have a HOLE, zero out the user-buffer for the
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* length of the hole or request.
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*/
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ret = len < nr ? len : nr;
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if (clear_user(buf, ret))
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ret = -EFAULT;
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} else {
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/*
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* We have the page, copy it to user space buffer.
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*/
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ret = hugetlbfs_read_actor(page, offset, buf, len, nr);
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}
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if (ret < 0) {
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if (retval == 0)
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retval = ret;
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if (page)
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page_cache_release(page);
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goto out;
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}
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offset += ret;
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retval += ret;
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len -= ret;
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index += offset >> HPAGE_SHIFT;
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offset &= ~HPAGE_MASK;
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if (page)
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page_cache_release(page);
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/* short read or no more work */
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if ((ret != nr) || (len == 0))
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break;
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}
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out:
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*ppos = ((loff_t)index << HPAGE_SHIFT) + offset;
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mutex_unlock(&inode->i_mutex);
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return retval;
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}
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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_write_begin(struct file *file,
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struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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return -EINVAL;
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}
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static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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BUG();
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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_SYNC)))
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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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|
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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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|
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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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|
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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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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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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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BUG_ON(offset & ~HPAGE_MASK);
|
|
pgoff = offset >> PAGE_SHIFT;
|
|
|
|
i_size_write(inode, offset);
|
|
spin_lock(&mapping->i_mmap_lock);
|
|
if (!prio_tree_empty(&mapping->i_mmap))
|
|
hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
|
|
spin_unlock(&mapping->i_mmap_lock);
|
|
truncate_hugepages(inode, offset);
|
|
return 0;
|
|
}
|
|
|
|
static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
int error;
|
|
unsigned int ia_valid = attr->ia_valid;
|
|
|
|
BUG_ON(!inode);
|
|
|
|
error = inode_change_ok(inode, attr);
|
|
if (error)
|
|
goto out;
|
|
|
|
if (ia_valid & ATTR_SIZE) {
|
|
error = -EINVAL;
|
|
if (!(attr->ia_size & ~HPAGE_MASK))
|
|
error = hugetlb_vmtruncate(inode, attr->ia_size);
|
|
if (error)
|
|
goto out;
|
|
attr->ia_valid &= ~ATTR_SIZE;
|
|
}
|
|
error = inode_setattr(inode, attr);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
|
|
gid_t gid, int mode, dev_t dev)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = new_inode(sb);
|
|
if (inode) {
|
|
struct hugetlbfs_inode_info *info;
|
|
inode->i_mode = mode;
|
|
inode->i_uid = uid;
|
|
inode->i_gid = gid;
|
|
inode->i_blocks = 0;
|
|
inode->i_mapping->a_ops = &hugetlbfs_aops;
|
|
inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
|
INIT_LIST_HEAD(&inode->i_mapping->private_list);
|
|
info = HUGETLBFS_I(inode);
|
|
mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, NULL);
|
|
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;
|
|
break;
|
|
}
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* File creation. Allocate an inode, and we're done..
|
|
*/
|
|
static int hugetlbfs_mknod(struct inode *dir,
|
|
struct dentry *dentry, int mode, dev_t dev)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
gid_t gid;
|
|
|
|
if (dir->i_mode & S_ISGID) {
|
|
gid = dir->i_gid;
|
|
if (S_ISDIR(mode))
|
|
mode |= S_ISGID;
|
|
} else {
|
|
gid = current->fsgid;
|
|
}
|
|
inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
|
|
if (inode) {
|
|
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
error = 0;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
|
|
{
|
|
int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
|
|
if (!retval)
|
|
inc_nlink(dir);
|
|
return retval;
|
|
}
|
|
|
|
static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
|
|
{
|
|
return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
|
|
}
|
|
|
|
static int hugetlbfs_symlink(struct inode *dir,
|
|
struct dentry *dentry, const char *symname)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
gid_t gid;
|
|
|
|
if (dir->i_mode & S_ISGID)
|
|
gid = dir->i_gid;
|
|
else
|
|
gid = current->fsgid;
|
|
|
|
inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
|
|
gid, S_IFLNK|S_IRWXUGO, 0);
|
|
if (inode) {
|
|
int l = strlen(symname)+1;
|
|
error = page_symlink(inode, symname, l);
|
|
if (!error) {
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
} else
|
|
iput(inode);
|
|
}
|
|
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* mark the head page dirty
|
|
*/
|
|
static int hugetlbfs_set_page_dirty(struct page *page)
|
|
{
|
|
struct page *head = compound_head(page);
|
|
|
|
SetPageDirty(head);
|
|
return 0;
|
|
}
|
|
|
|
static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
|
|
{
|
|
struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
|
|
|
|
buf->f_type = HUGETLBFS_MAGIC;
|
|
buf->f_bsize = HPAGE_SIZE;
|
|
if (sbinfo) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
/* If no limits set, just report 0 for max/free/used
|
|
* blocks, like simple_statfs() */
|
|
if (sbinfo->max_blocks >= 0) {
|
|
buf->f_blocks = sbinfo->max_blocks;
|
|
buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
|
|
buf->f_files = sbinfo->max_inodes;
|
|
buf->f_ffree = sbinfo->free_inodes;
|
|
}
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
buf->f_namelen = NAME_MAX;
|
|
return 0;
|
|
}
|
|
|
|
static void hugetlbfs_put_super(struct super_block *sb)
|
|
{
|
|
struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
|
|
|
|
if (sbi) {
|
|
sb->s_fs_info = NULL;
|
|
kfree(sbi);
|
|
}
|
|
}
|
|
|
|
static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
|
|
{
|
|
if (sbinfo->free_inodes >= 0) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
if (unlikely(!sbinfo->free_inodes)) {
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
return 0;
|
|
}
|
|
sbinfo->free_inodes--;
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
|
|
{
|
|
if (sbinfo->free_inodes >= 0) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
sbinfo->free_inodes++;
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
}
|
|
|
|
|
|
static 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,
|
|
.write_begin = hugetlbfs_write_begin,
|
|
.write_end = hugetlbfs_write_end,
|
|
.set_page_dirty = hugetlbfs_set_page_dirty,
|
|
};
|
|
|
|
|
|
static void init_once(struct kmem_cache *cachep, void *foo)
|
|
{
|
|
struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
|
|
|
|
inode_init_once(&ei->vfs_inode);
|
|
}
|
|
|
|
const struct file_operations hugetlbfs_file_operations = {
|
|
.read = hugetlbfs_read,
|
|
.mmap = hugetlbfs_file_mmap,
|
|
.fsync = simple_sync_file,
|
|
.get_unmapped_area = hugetlb_get_unmapped_area,
|
|
};
|
|
|
|
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,
|
|
};
|
|
|
|
static const struct inode_operations hugetlbfs_inode_operations = {
|
|
.setattr = hugetlbfs_setattr,
|
|
};
|
|
|
|
static const 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 *p, *rest;
|
|
substring_t args[MAX_OPT_ARGS];
|
|
int option;
|
|
|
|
if (!options)
|
|
return 0;
|
|
|
|
while ((p = strsep(&options, ",")) != NULL) {
|
|
int token;
|
|
if (!*p)
|
|
continue;
|
|
|
|
token = match_token(p, tokens, args);
|
|
switch (token) {
|
|
case Opt_uid:
|
|
if (match_int(&args[0], &option))
|
|
goto bad_val;
|
|
pconfig->uid = option;
|
|
break;
|
|
|
|
case Opt_gid:
|
|
if (match_int(&args[0], &option))
|
|
goto bad_val;
|
|
pconfig->gid = option;
|
|
break;
|
|
|
|
case Opt_mode:
|
|
if (match_octal(&args[0], &option))
|
|
goto bad_val;
|
|
pconfig->mode = option & 0777U;
|
|
break;
|
|
|
|
case Opt_size: {
|
|
unsigned long long size;
|
|
/* memparse() will accept a K/M/G without a digit */
|
|
if (!isdigit(*args[0].from))
|
|
goto bad_val;
|
|
size = memparse(args[0].from, &rest);
|
|
if (*rest == '%') {
|
|
size <<= HPAGE_SHIFT;
|
|
size *= max_huge_pages;
|
|
do_div(size, 100);
|
|
}
|
|
pconfig->nr_blocks = (size >> HPAGE_SHIFT);
|
|
break;
|
|
}
|
|
|
|
case Opt_nr_inodes:
|
|
/* memparse() will accept a K/M/G without a digit */
|
|
if (!isdigit(*args[0].from))
|
|
goto bad_val;
|
|
pconfig->nr_inodes = memparse(args[0].from, &rest);
|
|
break;
|
|
|
|
default:
|
|
printk(KERN_ERR "hugetlbfs: Bad mount option: \"%s\"\n",
|
|
p);
|
|
return -EINVAL;
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
bad_val:
|
|
printk(KERN_ERR "hugetlbfs: Bad value '%s' for mount option '%s'\n",
|
|
args[0].from, p);
|
|
return 1;
|
|
}
|
|
|
|
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_file_setup(const char *name, size_t size)
|
|
{
|
|
int error = -ENOMEM;
|
|
struct file *file;
|
|
struct inode *inode;
|
|
struct dentry *dentry, *root;
|
|
struct qstr quick_string;
|
|
|
|
if (!hugetlbfs_vfsmount)
|
|
return ERR_PTR(-ENOENT);
|
|
|
|
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;
|
|
quick_string.name = name;
|
|
quick_string.len = strlen(quick_string.name);
|
|
quick_string.hash = 0;
|
|
dentry = d_alloc(root, &quick_string);
|
|
if (!dentry)
|
|
goto out_shm_unlock;
|
|
|
|
error = -ENOSPC;
|
|
inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
|
|
current->fsgid, S_IFREG | S_IRWXUGO, 0);
|
|
if (!inode)
|
|
goto out_dentry;
|
|
|
|
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;
|
|
|
|
error = -ENFILE;
|
|
file = alloc_file(hugetlbfs_vfsmount, dentry,
|
|
FMODE_WRITE | FMODE_READ,
|
|
&hugetlbfs_file_operations);
|
|
if (!file)
|
|
goto out_inode;
|
|
|
|
return file;
|
|
|
|
out_inode:
|
|
iput(inode);
|
|
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;
|
|
|
|
error = bdi_init(&hugetlbfs_backing_dev_info);
|
|
if (error)
|
|
return error;
|
|
|
|
hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
|
|
sizeof(struct hugetlbfs_inode_info),
|
|
0, 0, init_once);
|
|
if (hugetlbfs_inode_cachep == NULL)
|
|
goto out2;
|
|
|
|
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);
|
|
out2:
|
|
bdi_destroy(&hugetlbfs_backing_dev_info);
|
|
return error;
|
|
}
|
|
|
|
static void __exit exit_hugetlbfs_fs(void)
|
|
{
|
|
kmem_cache_destroy(hugetlbfs_inode_cachep);
|
|
unregister_filesystem(&hugetlbfs_fs_type);
|
|
bdi_destroy(&hugetlbfs_backing_dev_info);
|
|
}
|
|
|
|
module_init(init_hugetlbfs_fs)
|
|
module_exit(exit_hugetlbfs_fs)
|
|
|
|
MODULE_LICENSE("GPL");
|