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![Rik van Riel](/assets/img/avatar_default.png)
Hugh pointed out that the gma500 driver uses shmem pages, but needs to limit them to the DMA32 zone. Ensure the allocations resulting from the gfp_mask returned by limit_gfp_mask use the zone flags that were originally passed to shmem_getpage_gfp. Link: https://lkml.kernel.org/r/20210224121016.1314ed6d@imladris.surriel.com Signed-off-by: Rik van Riel <riel@surriel.com> Suggested-by: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xu Yu <xuyu@linux.alibaba.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
4275 lines
110 KiB
C
4275 lines
110 KiB
C
/*
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* Resizable virtual memory filesystem for Linux.
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*
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* Copyright (C) 2000 Linus Torvalds.
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* 2000 Transmeta Corp.
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* 2000-2001 Christoph Rohland
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* 2000-2001 SAP AG
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* 2002 Red Hat Inc.
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* Copyright (C) 2002-2011 Hugh Dickins.
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* Copyright (C) 2011 Google Inc.
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* Copyright (C) 2002-2005 VERITAS Software Corporation.
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* Copyright (C) 2004 Andi Kleen, SuSE Labs
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*
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* Extended attribute support for tmpfs:
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* Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
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* Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
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*
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* tiny-shmem:
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* Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
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*
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* This file is released under the GPL.
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/vfs.h>
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#include <linux/mount.h>
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#include <linux/ramfs.h>
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#include <linux/pagemap.h>
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#include <linux/file.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/sched/signal.h>
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#include <linux/export.h>
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#include <linux/swap.h>
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#include <linux/uio.h>
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#include <linux/khugepaged.h>
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#include <linux/hugetlb.h>
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#include <linux/frontswap.h>
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#include <linux/fs_parser.h>
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#include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */
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static struct vfsmount *shm_mnt;
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#ifdef CONFIG_SHMEM
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/*
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* This virtual memory filesystem is heavily based on the ramfs. It
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* extends ramfs by the ability to use swap and honor resource limits
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* which makes it a completely usable filesystem.
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*/
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#include <linux/xattr.h>
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#include <linux/exportfs.h>
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#include <linux/posix_acl.h>
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#include <linux/posix_acl_xattr.h>
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#include <linux/mman.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/backing-dev.h>
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#include <linux/shmem_fs.h>
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#include <linux/writeback.h>
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#include <linux/blkdev.h>
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#include <linux/pagevec.h>
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#include <linux/percpu_counter.h>
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#include <linux/falloc.h>
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#include <linux/splice.h>
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#include <linux/security.h>
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#include <linux/swapops.h>
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#include <linux/mempolicy.h>
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#include <linux/namei.h>
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#include <linux/ctype.h>
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#include <linux/migrate.h>
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#include <linux/highmem.h>
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#include <linux/seq_file.h>
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#include <linux/magic.h>
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#include <linux/syscalls.h>
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#include <linux/fcntl.h>
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#include <uapi/linux/memfd.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/rmap.h>
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#include <linux/uuid.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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#define BLOCKS_PER_PAGE (PAGE_SIZE/512)
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#define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
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/* Pretend that each entry is of this size in directory's i_size */
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#define BOGO_DIRENT_SIZE 20
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/* Symlink up to this size is kmalloc'ed instead of using a swappable page */
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#define SHORT_SYMLINK_LEN 128
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/*
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* shmem_fallocate communicates with shmem_fault or shmem_writepage via
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* inode->i_private (with i_mutex making sure that it has only one user at
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* a time): we would prefer not to enlarge the shmem inode just for that.
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*/
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struct shmem_falloc {
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wait_queue_head_t *waitq; /* faults into hole wait for punch to end */
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pgoff_t start; /* start of range currently being fallocated */
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pgoff_t next; /* the next page offset to be fallocated */
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pgoff_t nr_falloced; /* how many new pages have been fallocated */
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pgoff_t nr_unswapped; /* how often writepage refused to swap out */
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};
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struct shmem_options {
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unsigned long long blocks;
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unsigned long long inodes;
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struct mempolicy *mpol;
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kuid_t uid;
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kgid_t gid;
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umode_t mode;
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bool full_inums;
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int huge;
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int seen;
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#define SHMEM_SEEN_BLOCKS 1
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#define SHMEM_SEEN_INODES 2
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#define SHMEM_SEEN_HUGE 4
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#define SHMEM_SEEN_INUMS 8
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};
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#ifdef CONFIG_TMPFS
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static unsigned long shmem_default_max_blocks(void)
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{
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return totalram_pages() / 2;
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}
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static unsigned long shmem_default_max_inodes(void)
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{
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unsigned long nr_pages = totalram_pages();
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return min(nr_pages - totalhigh_pages(), nr_pages / 2);
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}
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#endif
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static bool shmem_should_replace_page(struct page *page, gfp_t gfp);
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static int shmem_replace_page(struct page **pagep, gfp_t gfp,
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struct shmem_inode_info *info, pgoff_t index);
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static int shmem_swapin_page(struct inode *inode, pgoff_t index,
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struct page **pagep, enum sgp_type sgp,
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gfp_t gfp, struct vm_area_struct *vma,
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vm_fault_t *fault_type);
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static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
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struct page **pagep, enum sgp_type sgp,
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gfp_t gfp, struct vm_area_struct *vma,
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struct vm_fault *vmf, vm_fault_t *fault_type);
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int shmem_getpage(struct inode *inode, pgoff_t index,
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struct page **pagep, enum sgp_type sgp)
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{
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return shmem_getpage_gfp(inode, index, pagep, sgp,
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mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL);
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}
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static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
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{
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return sb->s_fs_info;
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}
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/*
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* shmem_file_setup pre-accounts the whole fixed size of a VM object,
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* for shared memory and for shared anonymous (/dev/zero) mappings
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* (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
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* consistent with the pre-accounting of private mappings ...
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*/
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static inline int shmem_acct_size(unsigned long flags, loff_t size)
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{
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return (flags & VM_NORESERVE) ?
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0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size));
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}
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static inline void shmem_unacct_size(unsigned long flags, loff_t size)
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{
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if (!(flags & VM_NORESERVE))
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vm_unacct_memory(VM_ACCT(size));
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}
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static inline int shmem_reacct_size(unsigned long flags,
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loff_t oldsize, loff_t newsize)
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{
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if (!(flags & VM_NORESERVE)) {
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if (VM_ACCT(newsize) > VM_ACCT(oldsize))
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return security_vm_enough_memory_mm(current->mm,
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VM_ACCT(newsize) - VM_ACCT(oldsize));
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else if (VM_ACCT(newsize) < VM_ACCT(oldsize))
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vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize));
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}
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return 0;
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}
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/*
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* ... whereas tmpfs objects are accounted incrementally as
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* pages are allocated, in order to allow large sparse files.
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* shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
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* so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
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*/
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static inline int shmem_acct_block(unsigned long flags, long pages)
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{
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if (!(flags & VM_NORESERVE))
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return 0;
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return security_vm_enough_memory_mm(current->mm,
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pages * VM_ACCT(PAGE_SIZE));
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}
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static inline void shmem_unacct_blocks(unsigned long flags, long pages)
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{
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if (flags & VM_NORESERVE)
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vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE));
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}
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static inline bool shmem_inode_acct_block(struct inode *inode, long pages)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
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if (shmem_acct_block(info->flags, pages))
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return false;
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if (sbinfo->max_blocks) {
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if (percpu_counter_compare(&sbinfo->used_blocks,
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sbinfo->max_blocks - pages) > 0)
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goto unacct;
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percpu_counter_add(&sbinfo->used_blocks, pages);
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}
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return true;
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unacct:
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shmem_unacct_blocks(info->flags, pages);
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return false;
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}
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static inline void shmem_inode_unacct_blocks(struct inode *inode, long pages)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
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if (sbinfo->max_blocks)
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percpu_counter_sub(&sbinfo->used_blocks, pages);
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shmem_unacct_blocks(info->flags, pages);
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}
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static const struct super_operations shmem_ops;
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const struct address_space_operations shmem_aops;
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static const struct file_operations shmem_file_operations;
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static const struct inode_operations shmem_inode_operations;
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static const struct inode_operations shmem_dir_inode_operations;
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static const struct inode_operations shmem_special_inode_operations;
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static const struct vm_operations_struct shmem_vm_ops;
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static struct file_system_type shmem_fs_type;
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bool vma_is_shmem(struct vm_area_struct *vma)
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{
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return vma->vm_ops == &shmem_vm_ops;
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}
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static LIST_HEAD(shmem_swaplist);
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static DEFINE_MUTEX(shmem_swaplist_mutex);
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/*
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* shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and
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* produces a novel ino for the newly allocated inode.
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*
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* It may also be called when making a hard link to permit the space needed by
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* each dentry. However, in that case, no new inode number is needed since that
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* internally draws from another pool of inode numbers (currently global
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* get_next_ino()). This case is indicated by passing NULL as inop.
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*/
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#define SHMEM_INO_BATCH 1024
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static int shmem_reserve_inode(struct super_block *sb, ino_t *inop)
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{
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struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
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ino_t ino;
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if (!(sb->s_flags & SB_KERNMOUNT)) {
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spin_lock(&sbinfo->stat_lock);
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if (sbinfo->max_inodes) {
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if (!sbinfo->free_inodes) {
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spin_unlock(&sbinfo->stat_lock);
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return -ENOSPC;
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}
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sbinfo->free_inodes--;
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}
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if (inop) {
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ino = sbinfo->next_ino++;
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if (unlikely(is_zero_ino(ino)))
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ino = sbinfo->next_ino++;
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if (unlikely(!sbinfo->full_inums &&
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ino > UINT_MAX)) {
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/*
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* Emulate get_next_ino uint wraparound for
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* compatibility
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*/
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if (IS_ENABLED(CONFIG_64BIT))
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pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n",
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__func__, MINOR(sb->s_dev));
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sbinfo->next_ino = 1;
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ino = sbinfo->next_ino++;
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}
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*inop = ino;
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}
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spin_unlock(&sbinfo->stat_lock);
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} else if (inop) {
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/*
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* __shmem_file_setup, one of our callers, is lock-free: it
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* doesn't hold stat_lock in shmem_reserve_inode since
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* max_inodes is always 0, and is called from potentially
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* unknown contexts. As such, use a per-cpu batched allocator
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* which doesn't require the per-sb stat_lock unless we are at
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* the batch boundary.
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*
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* We don't need to worry about inode{32,64} since SB_KERNMOUNT
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* shmem mounts are not exposed to userspace, so we don't need
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* to worry about things like glibc compatibility.
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*/
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ino_t *next_ino;
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next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu());
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ino = *next_ino;
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if (unlikely(ino % SHMEM_INO_BATCH == 0)) {
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spin_lock(&sbinfo->stat_lock);
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ino = sbinfo->next_ino;
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sbinfo->next_ino += SHMEM_INO_BATCH;
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spin_unlock(&sbinfo->stat_lock);
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if (unlikely(is_zero_ino(ino)))
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ino++;
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}
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*inop = ino;
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*next_ino = ++ino;
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put_cpu();
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}
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return 0;
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}
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static void shmem_free_inode(struct super_block *sb)
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{
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struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
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if (sbinfo->max_inodes) {
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spin_lock(&sbinfo->stat_lock);
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sbinfo->free_inodes++;
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spin_unlock(&sbinfo->stat_lock);
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}
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}
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/**
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* shmem_recalc_inode - recalculate the block usage of an inode
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* @inode: inode to recalc
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*
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* We have to calculate the free blocks since the mm can drop
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* undirtied hole pages behind our back.
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*
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* But normally info->alloced == inode->i_mapping->nrpages + info->swapped
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* So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
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*
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* It has to be called with the spinlock held.
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*/
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static void shmem_recalc_inode(struct inode *inode)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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long freed;
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freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
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if (freed > 0) {
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info->alloced -= freed;
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inode->i_blocks -= freed * BLOCKS_PER_PAGE;
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shmem_inode_unacct_blocks(inode, freed);
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}
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}
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bool shmem_charge(struct inode *inode, long pages)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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unsigned long flags;
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if (!shmem_inode_acct_block(inode, pages))
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return false;
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/* nrpages adjustment first, then shmem_recalc_inode() when balanced */
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inode->i_mapping->nrpages += pages;
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spin_lock_irqsave(&info->lock, flags);
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info->alloced += pages;
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inode->i_blocks += pages * BLOCKS_PER_PAGE;
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shmem_recalc_inode(inode);
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spin_unlock_irqrestore(&info->lock, flags);
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return true;
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}
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void shmem_uncharge(struct inode *inode, long pages)
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{
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struct shmem_inode_info *info = SHMEM_I(inode);
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unsigned long flags;
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/* nrpages adjustment done by __delete_from_page_cache() or caller */
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spin_lock_irqsave(&info->lock, flags);
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info->alloced -= pages;
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inode->i_blocks -= pages * BLOCKS_PER_PAGE;
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shmem_recalc_inode(inode);
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spin_unlock_irqrestore(&info->lock, flags);
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shmem_inode_unacct_blocks(inode, pages);
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}
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/*
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* Replace item expected in xarray by a new item, while holding xa_lock.
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*/
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static int shmem_replace_entry(struct address_space *mapping,
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pgoff_t index, void *expected, void *replacement)
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{
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XA_STATE(xas, &mapping->i_pages, index);
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void *item;
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VM_BUG_ON(!expected);
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VM_BUG_ON(!replacement);
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item = xas_load(&xas);
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if (item != expected)
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return -ENOENT;
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xas_store(&xas, replacement);
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return 0;
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}
|
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|
|
/*
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* Sometimes, before we decide whether to proceed or to fail, we must check
|
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* that an entry was not already brought back from swap by a racing thread.
|
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*
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* Checking page is not enough: by the time a SwapCache page is locked, it
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* might be reused, and again be SwapCache, using the same swap as before.
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*/
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static bool shmem_confirm_swap(struct address_space *mapping,
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pgoff_t index, swp_entry_t swap)
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{
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return xa_load(&mapping->i_pages, index) == swp_to_radix_entry(swap);
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}
|
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|
|
/*
|
|
* Definitions for "huge tmpfs": tmpfs mounted with the huge= option
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|
*
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* SHMEM_HUGE_NEVER:
|
|
* disables huge pages for the mount;
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* SHMEM_HUGE_ALWAYS:
|
|
* enables huge pages for the mount;
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* SHMEM_HUGE_WITHIN_SIZE:
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* only allocate huge pages if the page will be fully within i_size,
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* also respect fadvise()/madvise() hints;
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* SHMEM_HUGE_ADVISE:
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* only allocate huge pages if requested with fadvise()/madvise();
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*/
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|
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#define SHMEM_HUGE_NEVER 0
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#define SHMEM_HUGE_ALWAYS 1
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#define SHMEM_HUGE_WITHIN_SIZE 2
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#define SHMEM_HUGE_ADVISE 3
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|
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/*
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* Special values.
|
|
* Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
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*
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|
* SHMEM_HUGE_DENY:
|
|
* disables huge on shm_mnt and all mounts, for emergency use;
|
|
* SHMEM_HUGE_FORCE:
|
|
* enables huge on shm_mnt and all mounts, w/o needing option, for testing;
|
|
*
|
|
*/
|
|
#define SHMEM_HUGE_DENY (-1)
|
|
#define SHMEM_HUGE_FORCE (-2)
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
/* ifdef here to avoid bloating shmem.o when not necessary */
|
|
|
|
static int shmem_huge __read_mostly;
|
|
|
|
#if defined(CONFIG_SYSFS)
|
|
static int shmem_parse_huge(const char *str)
|
|
{
|
|
if (!strcmp(str, "never"))
|
|
return SHMEM_HUGE_NEVER;
|
|
if (!strcmp(str, "always"))
|
|
return SHMEM_HUGE_ALWAYS;
|
|
if (!strcmp(str, "within_size"))
|
|
return SHMEM_HUGE_WITHIN_SIZE;
|
|
if (!strcmp(str, "advise"))
|
|
return SHMEM_HUGE_ADVISE;
|
|
if (!strcmp(str, "deny"))
|
|
return SHMEM_HUGE_DENY;
|
|
if (!strcmp(str, "force"))
|
|
return SHMEM_HUGE_FORCE;
|
|
return -EINVAL;
|
|
}
|
|
#endif
|
|
|
|
#if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
|
|
static const char *shmem_format_huge(int huge)
|
|
{
|
|
switch (huge) {
|
|
case SHMEM_HUGE_NEVER:
|
|
return "never";
|
|
case SHMEM_HUGE_ALWAYS:
|
|
return "always";
|
|
case SHMEM_HUGE_WITHIN_SIZE:
|
|
return "within_size";
|
|
case SHMEM_HUGE_ADVISE:
|
|
return "advise";
|
|
case SHMEM_HUGE_DENY:
|
|
return "deny";
|
|
case SHMEM_HUGE_FORCE:
|
|
return "force";
|
|
default:
|
|
VM_BUG_ON(1);
|
|
return "bad_val";
|
|
}
|
|
}
|
|
#endif
|
|
|
|
static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
|
|
struct shrink_control *sc, unsigned long nr_to_split)
|
|
{
|
|
LIST_HEAD(list), *pos, *next;
|
|
LIST_HEAD(to_remove);
|
|
struct inode *inode;
|
|
struct shmem_inode_info *info;
|
|
struct page *page;
|
|
unsigned long batch = sc ? sc->nr_to_scan : 128;
|
|
int removed = 0, split = 0;
|
|
|
|
if (list_empty(&sbinfo->shrinklist))
|
|
return SHRINK_STOP;
|
|
|
|
spin_lock(&sbinfo->shrinklist_lock);
|
|
list_for_each_safe(pos, next, &sbinfo->shrinklist) {
|
|
info = list_entry(pos, struct shmem_inode_info, shrinklist);
|
|
|
|
/* pin the inode */
|
|
inode = igrab(&info->vfs_inode);
|
|
|
|
/* inode is about to be evicted */
|
|
if (!inode) {
|
|
list_del_init(&info->shrinklist);
|
|
removed++;
|
|
goto next;
|
|
}
|
|
|
|
/* Check if there's anything to gain */
|
|
if (round_up(inode->i_size, PAGE_SIZE) ==
|
|
round_up(inode->i_size, HPAGE_PMD_SIZE)) {
|
|
list_move(&info->shrinklist, &to_remove);
|
|
removed++;
|
|
goto next;
|
|
}
|
|
|
|
list_move(&info->shrinklist, &list);
|
|
next:
|
|
if (!--batch)
|
|
break;
|
|
}
|
|
spin_unlock(&sbinfo->shrinklist_lock);
|
|
|
|
list_for_each_safe(pos, next, &to_remove) {
|
|
info = list_entry(pos, struct shmem_inode_info, shrinklist);
|
|
inode = &info->vfs_inode;
|
|
list_del_init(&info->shrinklist);
|
|
iput(inode);
|
|
}
|
|
|
|
list_for_each_safe(pos, next, &list) {
|
|
int ret;
|
|
|
|
info = list_entry(pos, struct shmem_inode_info, shrinklist);
|
|
inode = &info->vfs_inode;
|
|
|
|
if (nr_to_split && split >= nr_to_split)
|
|
goto leave;
|
|
|
|
page = find_get_page(inode->i_mapping,
|
|
(inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT);
|
|
if (!page)
|
|
goto drop;
|
|
|
|
/* No huge page at the end of the file: nothing to split */
|
|
if (!PageTransHuge(page)) {
|
|
put_page(page);
|
|
goto drop;
|
|
}
|
|
|
|
/*
|
|
* Leave the inode on the list if we failed to lock
|
|
* the page at this time.
|
|
*
|
|
* Waiting for the lock may lead to deadlock in the
|
|
* reclaim path.
|
|
*/
|
|
if (!trylock_page(page)) {
|
|
put_page(page);
|
|
goto leave;
|
|
}
|
|
|
|
ret = split_huge_page(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
|
|
/* If split failed leave the inode on the list */
|
|
if (ret)
|
|
goto leave;
|
|
|
|
split++;
|
|
drop:
|
|
list_del_init(&info->shrinklist);
|
|
removed++;
|
|
leave:
|
|
iput(inode);
|
|
}
|
|
|
|
spin_lock(&sbinfo->shrinklist_lock);
|
|
list_splice_tail(&list, &sbinfo->shrinklist);
|
|
sbinfo->shrinklist_len -= removed;
|
|
spin_unlock(&sbinfo->shrinklist_lock);
|
|
|
|
return split;
|
|
}
|
|
|
|
static long shmem_unused_huge_scan(struct super_block *sb,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
|
|
if (!READ_ONCE(sbinfo->shrinklist_len))
|
|
return SHRINK_STOP;
|
|
|
|
return shmem_unused_huge_shrink(sbinfo, sc, 0);
|
|
}
|
|
|
|
static long shmem_unused_huge_count(struct super_block *sb,
|
|
struct shrink_control *sc)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
return READ_ONCE(sbinfo->shrinklist_len);
|
|
}
|
|
#else /* !CONFIG_TRANSPARENT_HUGEPAGE */
|
|
|
|
#define shmem_huge SHMEM_HUGE_DENY
|
|
|
|
static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
|
|
struct shrink_control *sc, unsigned long nr_to_split)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
|
|
|
|
static inline bool is_huge_enabled(struct shmem_sb_info *sbinfo)
|
|
{
|
|
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
|
|
(shmem_huge == SHMEM_HUGE_FORCE || sbinfo->huge) &&
|
|
shmem_huge != SHMEM_HUGE_DENY)
|
|
return true;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Like add_to_page_cache_locked, but error if expected item has gone.
|
|
*/
|
|
static int shmem_add_to_page_cache(struct page *page,
|
|
struct address_space *mapping,
|
|
pgoff_t index, void *expected, gfp_t gfp,
|
|
struct mm_struct *charge_mm)
|
|
{
|
|
XA_STATE_ORDER(xas, &mapping->i_pages, index, compound_order(page));
|
|
unsigned long i = 0;
|
|
unsigned long nr = compound_nr(page);
|
|
int error;
|
|
|
|
VM_BUG_ON_PAGE(PageTail(page), page);
|
|
VM_BUG_ON_PAGE(index != round_down(index, nr), page);
|
|
VM_BUG_ON_PAGE(!PageLocked(page), page);
|
|
VM_BUG_ON_PAGE(!PageSwapBacked(page), page);
|
|
VM_BUG_ON(expected && PageTransHuge(page));
|
|
|
|
page_ref_add(page, nr);
|
|
page->mapping = mapping;
|
|
page->index = index;
|
|
|
|
if (!PageSwapCache(page)) {
|
|
error = mem_cgroup_charge(page, charge_mm, gfp);
|
|
if (error) {
|
|
if (PageTransHuge(page)) {
|
|
count_vm_event(THP_FILE_FALLBACK);
|
|
count_vm_event(THP_FILE_FALLBACK_CHARGE);
|
|
}
|
|
goto error;
|
|
}
|
|
}
|
|
cgroup_throttle_swaprate(page, gfp);
|
|
|
|
do {
|
|
void *entry;
|
|
xas_lock_irq(&xas);
|
|
entry = xas_find_conflict(&xas);
|
|
if (entry != expected)
|
|
xas_set_err(&xas, -EEXIST);
|
|
xas_create_range(&xas);
|
|
if (xas_error(&xas))
|
|
goto unlock;
|
|
next:
|
|
xas_store(&xas, page);
|
|
if (++i < nr) {
|
|
xas_next(&xas);
|
|
goto next;
|
|
}
|
|
if (PageTransHuge(page)) {
|
|
count_vm_event(THP_FILE_ALLOC);
|
|
__mod_lruvec_page_state(page, NR_SHMEM_THPS, nr);
|
|
}
|
|
mapping->nrpages += nr;
|
|
__mod_lruvec_page_state(page, NR_FILE_PAGES, nr);
|
|
__mod_lruvec_page_state(page, NR_SHMEM, nr);
|
|
unlock:
|
|
xas_unlock_irq(&xas);
|
|
} while (xas_nomem(&xas, gfp));
|
|
|
|
if (xas_error(&xas)) {
|
|
error = xas_error(&xas);
|
|
goto error;
|
|
}
|
|
|
|
return 0;
|
|
error:
|
|
page->mapping = NULL;
|
|
page_ref_sub(page, nr);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Like delete_from_page_cache, but substitutes swap for page.
|
|
*/
|
|
static void shmem_delete_from_page_cache(struct page *page, void *radswap)
|
|
{
|
|
struct address_space *mapping = page->mapping;
|
|
int error;
|
|
|
|
VM_BUG_ON_PAGE(PageCompound(page), page);
|
|
|
|
xa_lock_irq(&mapping->i_pages);
|
|
error = shmem_replace_entry(mapping, page->index, page, radswap);
|
|
page->mapping = NULL;
|
|
mapping->nrpages--;
|
|
__dec_lruvec_page_state(page, NR_FILE_PAGES);
|
|
__dec_lruvec_page_state(page, NR_SHMEM);
|
|
xa_unlock_irq(&mapping->i_pages);
|
|
put_page(page);
|
|
BUG_ON(error);
|
|
}
|
|
|
|
/*
|
|
* Remove swap entry from page cache, free the swap and its page cache.
|
|
*/
|
|
static int shmem_free_swap(struct address_space *mapping,
|
|
pgoff_t index, void *radswap)
|
|
{
|
|
void *old;
|
|
|
|
old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0);
|
|
if (old != radswap)
|
|
return -ENOENT;
|
|
free_swap_and_cache(radix_to_swp_entry(radswap));
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Determine (in bytes) how many of the shmem object's pages mapped by the
|
|
* given offsets are swapped out.
|
|
*
|
|
* This is safe to call without i_mutex or the i_pages lock thanks to RCU,
|
|
* as long as the inode doesn't go away and racy results are not a problem.
|
|
*/
|
|
unsigned long shmem_partial_swap_usage(struct address_space *mapping,
|
|
pgoff_t start, pgoff_t end)
|
|
{
|
|
XA_STATE(xas, &mapping->i_pages, start);
|
|
struct page *page;
|
|
unsigned long swapped = 0;
|
|
|
|
rcu_read_lock();
|
|
xas_for_each(&xas, page, end - 1) {
|
|
if (xas_retry(&xas, page))
|
|
continue;
|
|
if (xa_is_value(page))
|
|
swapped++;
|
|
|
|
if (need_resched()) {
|
|
xas_pause(&xas);
|
|
cond_resched_rcu();
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
|
|
return swapped << PAGE_SHIFT;
|
|
}
|
|
|
|
/*
|
|
* Determine (in bytes) how many of the shmem object's pages mapped by the
|
|
* given vma is swapped out.
|
|
*
|
|
* This is safe to call without i_mutex or the i_pages lock thanks to RCU,
|
|
* as long as the inode doesn't go away and racy results are not a problem.
|
|
*/
|
|
unsigned long shmem_swap_usage(struct vm_area_struct *vma)
|
|
{
|
|
struct inode *inode = file_inode(vma->vm_file);
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct address_space *mapping = inode->i_mapping;
|
|
unsigned long swapped;
|
|
|
|
/* Be careful as we don't hold info->lock */
|
|
swapped = READ_ONCE(info->swapped);
|
|
|
|
/*
|
|
* The easier cases are when the shmem object has nothing in swap, or
|
|
* the vma maps it whole. Then we can simply use the stats that we
|
|
* already track.
|
|
*/
|
|
if (!swapped)
|
|
return 0;
|
|
|
|
if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size)
|
|
return swapped << PAGE_SHIFT;
|
|
|
|
/* Here comes the more involved part */
|
|
return shmem_partial_swap_usage(mapping,
|
|
linear_page_index(vma, vma->vm_start),
|
|
linear_page_index(vma, vma->vm_end));
|
|
}
|
|
|
|
/*
|
|
* SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
|
|
*/
|
|
void shmem_unlock_mapping(struct address_space *mapping)
|
|
{
|
|
struct pagevec pvec;
|
|
pgoff_t index = 0;
|
|
|
|
pagevec_init(&pvec);
|
|
/*
|
|
* Minor point, but we might as well stop if someone else SHM_LOCKs it.
|
|
*/
|
|
while (!mapping_unevictable(mapping)) {
|
|
if (!pagevec_lookup(&pvec, mapping, &index))
|
|
break;
|
|
check_move_unevictable_pages(&pvec);
|
|
pagevec_release(&pvec);
|
|
cond_resched();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check whether a hole-punch or truncation needs to split a huge page,
|
|
* returning true if no split was required, or the split has been successful.
|
|
*
|
|
* Eviction (or truncation to 0 size) should never need to split a huge page;
|
|
* but in rare cases might do so, if shmem_undo_range() failed to trylock on
|
|
* head, and then succeeded to trylock on tail.
|
|
*
|
|
* A split can only succeed when there are no additional references on the
|
|
* huge page: so the split below relies upon find_get_entries() having stopped
|
|
* when it found a subpage of the huge page, without getting further references.
|
|
*/
|
|
static bool shmem_punch_compound(struct page *page, pgoff_t start, pgoff_t end)
|
|
{
|
|
if (!PageTransCompound(page))
|
|
return true;
|
|
|
|
/* Just proceed to delete a huge page wholly within the range punched */
|
|
if (PageHead(page) &&
|
|
page->index >= start && page->index + HPAGE_PMD_NR <= end)
|
|
return true;
|
|
|
|
/* Try to split huge page, so we can truly punch the hole or truncate */
|
|
return split_huge_page(page) >= 0;
|
|
}
|
|
|
|
/*
|
|
* Remove range of pages and swap entries from page cache, and free them.
|
|
* If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
|
|
*/
|
|
static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
|
|
bool unfalloc)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
pgoff_t end = (lend + 1) >> PAGE_SHIFT;
|
|
unsigned int partial_start = lstart & (PAGE_SIZE - 1);
|
|
unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1);
|
|
struct pagevec pvec;
|
|
pgoff_t indices[PAGEVEC_SIZE];
|
|
long nr_swaps_freed = 0;
|
|
pgoff_t index;
|
|
int i;
|
|
|
|
if (lend == -1)
|
|
end = -1; /* unsigned, so actually very big */
|
|
|
|
pagevec_init(&pvec);
|
|
index = start;
|
|
while (index < end && find_lock_entries(mapping, index, end - 1,
|
|
&pvec, indices)) {
|
|
for (i = 0; i < pagevec_count(&pvec); i++) {
|
|
struct page *page = pvec.pages[i];
|
|
|
|
index = indices[i];
|
|
|
|
if (xa_is_value(page)) {
|
|
if (unfalloc)
|
|
continue;
|
|
nr_swaps_freed += !shmem_free_swap(mapping,
|
|
index, page);
|
|
continue;
|
|
}
|
|
index += thp_nr_pages(page) - 1;
|
|
|
|
if (!unfalloc || !PageUptodate(page))
|
|
truncate_inode_page(mapping, page);
|
|
unlock_page(page);
|
|
}
|
|
pagevec_remove_exceptionals(&pvec);
|
|
pagevec_release(&pvec);
|
|
cond_resched();
|
|
index++;
|
|
}
|
|
|
|
if (partial_start) {
|
|
struct page *page = NULL;
|
|
shmem_getpage(inode, start - 1, &page, SGP_READ);
|
|
if (page) {
|
|
unsigned int top = PAGE_SIZE;
|
|
if (start > end) {
|
|
top = partial_end;
|
|
partial_end = 0;
|
|
}
|
|
zero_user_segment(page, partial_start, top);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
}
|
|
}
|
|
if (partial_end) {
|
|
struct page *page = NULL;
|
|
shmem_getpage(inode, end, &page, SGP_READ);
|
|
if (page) {
|
|
zero_user_segment(page, 0, partial_end);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
}
|
|
}
|
|
if (start >= end)
|
|
return;
|
|
|
|
index = start;
|
|
while (index < end) {
|
|
cond_resched();
|
|
|
|
if (!find_get_entries(mapping, index, end - 1, &pvec,
|
|
indices)) {
|
|
/* If all gone or hole-punch or unfalloc, we're done */
|
|
if (index == start || end != -1)
|
|
break;
|
|
/* But if truncating, restart to make sure all gone */
|
|
index = start;
|
|
continue;
|
|
}
|
|
for (i = 0; i < pagevec_count(&pvec); i++) {
|
|
struct page *page = pvec.pages[i];
|
|
|
|
index = indices[i];
|
|
if (xa_is_value(page)) {
|
|
if (unfalloc)
|
|
continue;
|
|
if (shmem_free_swap(mapping, index, page)) {
|
|
/* Swap was replaced by page: retry */
|
|
index--;
|
|
break;
|
|
}
|
|
nr_swaps_freed++;
|
|
continue;
|
|
}
|
|
|
|
lock_page(page);
|
|
|
|
if (!unfalloc || !PageUptodate(page)) {
|
|
if (page_mapping(page) != mapping) {
|
|
/* Page was replaced by swap: retry */
|
|
unlock_page(page);
|
|
index--;
|
|
break;
|
|
}
|
|
VM_BUG_ON_PAGE(PageWriteback(page), page);
|
|
if (shmem_punch_compound(page, start, end))
|
|
truncate_inode_page(mapping, page);
|
|
else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
|
|
/* Wipe the page and don't get stuck */
|
|
clear_highpage(page);
|
|
flush_dcache_page(page);
|
|
set_page_dirty(page);
|
|
if (index <
|
|
round_up(start, HPAGE_PMD_NR))
|
|
start = index + 1;
|
|
}
|
|
}
|
|
unlock_page(page);
|
|
}
|
|
pagevec_remove_exceptionals(&pvec);
|
|
pagevec_release(&pvec);
|
|
index++;
|
|
}
|
|
|
|
spin_lock_irq(&info->lock);
|
|
info->swapped -= nr_swaps_freed;
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
}
|
|
|
|
void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
|
|
{
|
|
shmem_undo_range(inode, lstart, lend, false);
|
|
inode->i_ctime = inode->i_mtime = current_time(inode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_truncate_range);
|
|
|
|
static int shmem_getattr(struct user_namespace *mnt_userns,
|
|
const struct path *path, struct kstat *stat,
|
|
u32 request_mask, unsigned int query_flags)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_sb_info *sb_info = SHMEM_SB(inode->i_sb);
|
|
|
|
if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
|
|
spin_lock_irq(&info->lock);
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
}
|
|
generic_fillattr(&init_user_ns, inode, stat);
|
|
|
|
if (is_huge_enabled(sb_info))
|
|
stat->blksize = HPAGE_PMD_SIZE;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_setattr(struct user_namespace *mnt_userns,
|
|
struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
|
int error;
|
|
|
|
error = setattr_prepare(&init_user_ns, dentry, attr);
|
|
if (error)
|
|
return error;
|
|
|
|
if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
|
|
loff_t oldsize = inode->i_size;
|
|
loff_t newsize = attr->ia_size;
|
|
|
|
/* protected by i_mutex */
|
|
if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) ||
|
|
(newsize > oldsize && (info->seals & F_SEAL_GROW)))
|
|
return -EPERM;
|
|
|
|
if (newsize != oldsize) {
|
|
error = shmem_reacct_size(SHMEM_I(inode)->flags,
|
|
oldsize, newsize);
|
|
if (error)
|
|
return error;
|
|
i_size_write(inode, newsize);
|
|
inode->i_ctime = inode->i_mtime = current_time(inode);
|
|
}
|
|
if (newsize <= oldsize) {
|
|
loff_t holebegin = round_up(newsize, PAGE_SIZE);
|
|
if (oldsize > holebegin)
|
|
unmap_mapping_range(inode->i_mapping,
|
|
holebegin, 0, 1);
|
|
if (info->alloced)
|
|
shmem_truncate_range(inode,
|
|
newsize, (loff_t)-1);
|
|
/* unmap again to remove racily COWed private pages */
|
|
if (oldsize > holebegin)
|
|
unmap_mapping_range(inode->i_mapping,
|
|
holebegin, 0, 1);
|
|
|
|
/*
|
|
* Part of the huge page can be beyond i_size: subject
|
|
* to shrink under memory pressure.
|
|
*/
|
|
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
|
|
spin_lock(&sbinfo->shrinklist_lock);
|
|
/*
|
|
* _careful to defend against unlocked access to
|
|
* ->shrink_list in shmem_unused_huge_shrink()
|
|
*/
|
|
if (list_empty_careful(&info->shrinklist)) {
|
|
list_add_tail(&info->shrinklist,
|
|
&sbinfo->shrinklist);
|
|
sbinfo->shrinklist_len++;
|
|
}
|
|
spin_unlock(&sbinfo->shrinklist_lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
setattr_copy(&init_user_ns, inode, attr);
|
|
if (attr->ia_valid & ATTR_MODE)
|
|
error = posix_acl_chmod(&init_user_ns, inode, inode->i_mode);
|
|
return error;
|
|
}
|
|
|
|
static void shmem_evict_inode(struct inode *inode)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
|
|
|
if (shmem_mapping(inode->i_mapping)) {
|
|
shmem_unacct_size(info->flags, inode->i_size);
|
|
inode->i_size = 0;
|
|
shmem_truncate_range(inode, 0, (loff_t)-1);
|
|
if (!list_empty(&info->shrinklist)) {
|
|
spin_lock(&sbinfo->shrinklist_lock);
|
|
if (!list_empty(&info->shrinklist)) {
|
|
list_del_init(&info->shrinklist);
|
|
sbinfo->shrinklist_len--;
|
|
}
|
|
spin_unlock(&sbinfo->shrinklist_lock);
|
|
}
|
|
while (!list_empty(&info->swaplist)) {
|
|
/* Wait while shmem_unuse() is scanning this inode... */
|
|
wait_var_event(&info->stop_eviction,
|
|
!atomic_read(&info->stop_eviction));
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
/* ...but beware of the race if we peeked too early */
|
|
if (!atomic_read(&info->stop_eviction))
|
|
list_del_init(&info->swaplist);
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
}
|
|
}
|
|
|
|
simple_xattrs_free(&info->xattrs);
|
|
WARN_ON(inode->i_blocks);
|
|
shmem_free_inode(inode->i_sb);
|
|
clear_inode(inode);
|
|
}
|
|
|
|
extern struct swap_info_struct *swap_info[];
|
|
|
|
static int shmem_find_swap_entries(struct address_space *mapping,
|
|
pgoff_t start, unsigned int nr_entries,
|
|
struct page **entries, pgoff_t *indices,
|
|
unsigned int type, bool frontswap)
|
|
{
|
|
XA_STATE(xas, &mapping->i_pages, start);
|
|
struct page *page;
|
|
swp_entry_t entry;
|
|
unsigned int ret = 0;
|
|
|
|
if (!nr_entries)
|
|
return 0;
|
|
|
|
rcu_read_lock();
|
|
xas_for_each(&xas, page, ULONG_MAX) {
|
|
if (xas_retry(&xas, page))
|
|
continue;
|
|
|
|
if (!xa_is_value(page))
|
|
continue;
|
|
|
|
entry = radix_to_swp_entry(page);
|
|
if (swp_type(entry) != type)
|
|
continue;
|
|
if (frontswap &&
|
|
!frontswap_test(swap_info[type], swp_offset(entry)))
|
|
continue;
|
|
|
|
indices[ret] = xas.xa_index;
|
|
entries[ret] = page;
|
|
|
|
if (need_resched()) {
|
|
xas_pause(&xas);
|
|
cond_resched_rcu();
|
|
}
|
|
if (++ret == nr_entries)
|
|
break;
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Move the swapped pages for an inode to page cache. Returns the count
|
|
* of pages swapped in, or the error in case of failure.
|
|
*/
|
|
static int shmem_unuse_swap_entries(struct inode *inode, struct pagevec pvec,
|
|
pgoff_t *indices)
|
|
{
|
|
int i = 0;
|
|
int ret = 0;
|
|
int error = 0;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
|
|
for (i = 0; i < pvec.nr; i++) {
|
|
struct page *page = pvec.pages[i];
|
|
|
|
if (!xa_is_value(page))
|
|
continue;
|
|
error = shmem_swapin_page(inode, indices[i],
|
|
&page, SGP_CACHE,
|
|
mapping_gfp_mask(mapping),
|
|
NULL, NULL);
|
|
if (error == 0) {
|
|
unlock_page(page);
|
|
put_page(page);
|
|
ret++;
|
|
}
|
|
if (error == -ENOMEM)
|
|
break;
|
|
error = 0;
|
|
}
|
|
return error ? error : ret;
|
|
}
|
|
|
|
/*
|
|
* If swap found in inode, free it and move page from swapcache to filecache.
|
|
*/
|
|
static int shmem_unuse_inode(struct inode *inode, unsigned int type,
|
|
bool frontswap, unsigned long *fs_pages_to_unuse)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
pgoff_t start = 0;
|
|
struct pagevec pvec;
|
|
pgoff_t indices[PAGEVEC_SIZE];
|
|
bool frontswap_partial = (frontswap && *fs_pages_to_unuse > 0);
|
|
int ret = 0;
|
|
|
|
pagevec_init(&pvec);
|
|
do {
|
|
unsigned int nr_entries = PAGEVEC_SIZE;
|
|
|
|
if (frontswap_partial && *fs_pages_to_unuse < PAGEVEC_SIZE)
|
|
nr_entries = *fs_pages_to_unuse;
|
|
|
|
pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries,
|
|
pvec.pages, indices,
|
|
type, frontswap);
|
|
if (pvec.nr == 0) {
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
ret = shmem_unuse_swap_entries(inode, pvec, indices);
|
|
if (ret < 0)
|
|
break;
|
|
|
|
if (frontswap_partial) {
|
|
*fs_pages_to_unuse -= ret;
|
|
if (*fs_pages_to_unuse == 0) {
|
|
ret = FRONTSWAP_PAGES_UNUSED;
|
|
break;
|
|
}
|
|
}
|
|
|
|
start = indices[pvec.nr - 1];
|
|
} while (true);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Read all the shared memory data that resides in the swap
|
|
* device 'type' back into memory, so the swap device can be
|
|
* unused.
|
|
*/
|
|
int shmem_unuse(unsigned int type, bool frontswap,
|
|
unsigned long *fs_pages_to_unuse)
|
|
{
|
|
struct shmem_inode_info *info, *next;
|
|
int error = 0;
|
|
|
|
if (list_empty(&shmem_swaplist))
|
|
return 0;
|
|
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
list_for_each_entry_safe(info, next, &shmem_swaplist, swaplist) {
|
|
if (!info->swapped) {
|
|
list_del_init(&info->swaplist);
|
|
continue;
|
|
}
|
|
/*
|
|
* Drop the swaplist mutex while searching the inode for swap;
|
|
* but before doing so, make sure shmem_evict_inode() will not
|
|
* remove placeholder inode from swaplist, nor let it be freed
|
|
* (igrab() would protect from unlink, but not from unmount).
|
|
*/
|
|
atomic_inc(&info->stop_eviction);
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
|
|
error = shmem_unuse_inode(&info->vfs_inode, type, frontswap,
|
|
fs_pages_to_unuse);
|
|
cond_resched();
|
|
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
next = list_next_entry(info, swaplist);
|
|
if (!info->swapped)
|
|
list_del_init(&info->swaplist);
|
|
if (atomic_dec_and_test(&info->stop_eviction))
|
|
wake_up_var(&info->stop_eviction);
|
|
if (error)
|
|
break;
|
|
}
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Move the page from the page cache to the swap cache.
|
|
*/
|
|
static int shmem_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
struct shmem_inode_info *info;
|
|
struct address_space *mapping;
|
|
struct inode *inode;
|
|
swp_entry_t swap;
|
|
pgoff_t index;
|
|
|
|
VM_BUG_ON_PAGE(PageCompound(page), page);
|
|
BUG_ON(!PageLocked(page));
|
|
mapping = page->mapping;
|
|
index = page->index;
|
|
inode = mapping->host;
|
|
info = SHMEM_I(inode);
|
|
if (info->flags & VM_LOCKED)
|
|
goto redirty;
|
|
if (!total_swap_pages)
|
|
goto redirty;
|
|
|
|
/*
|
|
* Our capabilities prevent regular writeback or sync from ever calling
|
|
* shmem_writepage; but a stacking filesystem might use ->writepage of
|
|
* its underlying filesystem, in which case tmpfs should write out to
|
|
* swap only in response to memory pressure, and not for the writeback
|
|
* threads or sync.
|
|
*/
|
|
if (!wbc->for_reclaim) {
|
|
WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
|
|
goto redirty;
|
|
}
|
|
|
|
/*
|
|
* This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
|
|
* value into swapfile.c, the only way we can correctly account for a
|
|
* fallocated page arriving here is now to initialize it and write it.
|
|
*
|
|
* That's okay for a page already fallocated earlier, but if we have
|
|
* not yet completed the fallocation, then (a) we want to keep track
|
|
* of this page in case we have to undo it, and (b) it may not be a
|
|
* good idea to continue anyway, once we're pushing into swap. So
|
|
* reactivate the page, and let shmem_fallocate() quit when too many.
|
|
*/
|
|
if (!PageUptodate(page)) {
|
|
if (inode->i_private) {
|
|
struct shmem_falloc *shmem_falloc;
|
|
spin_lock(&inode->i_lock);
|
|
shmem_falloc = inode->i_private;
|
|
if (shmem_falloc &&
|
|
!shmem_falloc->waitq &&
|
|
index >= shmem_falloc->start &&
|
|
index < shmem_falloc->next)
|
|
shmem_falloc->nr_unswapped++;
|
|
else
|
|
shmem_falloc = NULL;
|
|
spin_unlock(&inode->i_lock);
|
|
if (shmem_falloc)
|
|
goto redirty;
|
|
}
|
|
clear_highpage(page);
|
|
flush_dcache_page(page);
|
|
SetPageUptodate(page);
|
|
}
|
|
|
|
swap = get_swap_page(page);
|
|
if (!swap.val)
|
|
goto redirty;
|
|
|
|
/*
|
|
* Add inode to shmem_unuse()'s list of swapped-out inodes,
|
|
* if it's not already there. Do it now before the page is
|
|
* moved to swap cache, when its pagelock no longer protects
|
|
* the inode from eviction. But don't unlock the mutex until
|
|
* we've incremented swapped, because shmem_unuse_inode() will
|
|
* prune a !swapped inode from the swaplist under this mutex.
|
|
*/
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
if (list_empty(&info->swaplist))
|
|
list_add(&info->swaplist, &shmem_swaplist);
|
|
|
|
if (add_to_swap_cache(page, swap,
|
|
__GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN,
|
|
NULL) == 0) {
|
|
spin_lock_irq(&info->lock);
|
|
shmem_recalc_inode(inode);
|
|
info->swapped++;
|
|
spin_unlock_irq(&info->lock);
|
|
|
|
swap_shmem_alloc(swap);
|
|
shmem_delete_from_page_cache(page, swp_to_radix_entry(swap));
|
|
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
BUG_ON(page_mapped(page));
|
|
swap_writepage(page, wbc);
|
|
return 0;
|
|
}
|
|
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
put_swap_page(page, swap);
|
|
redirty:
|
|
set_page_dirty(page);
|
|
if (wbc->for_reclaim)
|
|
return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
#if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
|
|
static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
|
|
{
|
|
char buffer[64];
|
|
|
|
if (!mpol || mpol->mode == MPOL_DEFAULT)
|
|
return; /* show nothing */
|
|
|
|
mpol_to_str(buffer, sizeof(buffer), mpol);
|
|
|
|
seq_printf(seq, ",mpol=%s", buffer);
|
|
}
|
|
|
|
static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
|
|
{
|
|
struct mempolicy *mpol = NULL;
|
|
if (sbinfo->mpol) {
|
|
spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */
|
|
mpol = sbinfo->mpol;
|
|
mpol_get(mpol);
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
}
|
|
return mpol;
|
|
}
|
|
#else /* !CONFIG_NUMA || !CONFIG_TMPFS */
|
|
static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
|
|
{
|
|
}
|
|
static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif /* CONFIG_NUMA && CONFIG_TMPFS */
|
|
#ifndef CONFIG_NUMA
|
|
#define vm_policy vm_private_data
|
|
#endif
|
|
|
|
static void shmem_pseudo_vma_init(struct vm_area_struct *vma,
|
|
struct shmem_inode_info *info, pgoff_t index)
|
|
{
|
|
/* Create a pseudo vma that just contains the policy */
|
|
vma_init(vma, NULL);
|
|
/* Bias interleave by inode number to distribute better across nodes */
|
|
vma->vm_pgoff = index + info->vfs_inode.i_ino;
|
|
vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index);
|
|
}
|
|
|
|
static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma)
|
|
{
|
|
/* Drop reference taken by mpol_shared_policy_lookup() */
|
|
mpol_cond_put(vma->vm_policy);
|
|
}
|
|
|
|
static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
|
|
struct shmem_inode_info *info, pgoff_t index)
|
|
{
|
|
struct vm_area_struct pvma;
|
|
struct page *page;
|
|
struct vm_fault vmf = {
|
|
.vma = &pvma,
|
|
};
|
|
|
|
shmem_pseudo_vma_init(&pvma, info, index);
|
|
page = swap_cluster_readahead(swap, gfp, &vmf);
|
|
shmem_pseudo_vma_destroy(&pvma);
|
|
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Make sure huge_gfp is always more limited than limit_gfp.
|
|
* Some of the flags set permissions, while others set limitations.
|
|
*/
|
|
static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp)
|
|
{
|
|
gfp_t allowflags = __GFP_IO | __GFP_FS | __GFP_RECLAIM;
|
|
gfp_t denyflags = __GFP_NOWARN | __GFP_NORETRY;
|
|
gfp_t zoneflags = limit_gfp & GFP_ZONEMASK;
|
|
gfp_t result = huge_gfp & ~(allowflags | GFP_ZONEMASK);
|
|
|
|
/* Allow allocations only from the originally specified zones. */
|
|
result |= zoneflags;
|
|
|
|
/*
|
|
* Minimize the result gfp by taking the union with the deny flags,
|
|
* and the intersection of the allow flags.
|
|
*/
|
|
result |= (limit_gfp & denyflags);
|
|
result |= (huge_gfp & limit_gfp) & allowflags;
|
|
|
|
return result;
|
|
}
|
|
|
|
static struct page *shmem_alloc_hugepage(gfp_t gfp,
|
|
struct shmem_inode_info *info, pgoff_t index)
|
|
{
|
|
struct vm_area_struct pvma;
|
|
struct address_space *mapping = info->vfs_inode.i_mapping;
|
|
pgoff_t hindex;
|
|
struct page *page;
|
|
|
|
hindex = round_down(index, HPAGE_PMD_NR);
|
|
if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,
|
|
XA_PRESENT))
|
|
return NULL;
|
|
|
|
shmem_pseudo_vma_init(&pvma, info, hindex);
|
|
page = alloc_pages_vma(gfp, HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(),
|
|
true);
|
|
shmem_pseudo_vma_destroy(&pvma);
|
|
if (page)
|
|
prep_transhuge_page(page);
|
|
else
|
|
count_vm_event(THP_FILE_FALLBACK);
|
|
return page;
|
|
}
|
|
|
|
static struct page *shmem_alloc_page(gfp_t gfp,
|
|
struct shmem_inode_info *info, pgoff_t index)
|
|
{
|
|
struct vm_area_struct pvma;
|
|
struct page *page;
|
|
|
|
shmem_pseudo_vma_init(&pvma, info, index);
|
|
page = alloc_page_vma(gfp, &pvma, 0);
|
|
shmem_pseudo_vma_destroy(&pvma);
|
|
|
|
return page;
|
|
}
|
|
|
|
static struct page *shmem_alloc_and_acct_page(gfp_t gfp,
|
|
struct inode *inode,
|
|
pgoff_t index, bool huge)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct page *page;
|
|
int nr;
|
|
int err = -ENOSPC;
|
|
|
|
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
|
|
huge = false;
|
|
nr = huge ? HPAGE_PMD_NR : 1;
|
|
|
|
if (!shmem_inode_acct_block(inode, nr))
|
|
goto failed;
|
|
|
|
if (huge)
|
|
page = shmem_alloc_hugepage(gfp, info, index);
|
|
else
|
|
page = shmem_alloc_page(gfp, info, index);
|
|
if (page) {
|
|
__SetPageLocked(page);
|
|
__SetPageSwapBacked(page);
|
|
return page;
|
|
}
|
|
|
|
err = -ENOMEM;
|
|
shmem_inode_unacct_blocks(inode, nr);
|
|
failed:
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/*
|
|
* When a page is moved from swapcache to shmem filecache (either by the
|
|
* usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
|
|
* shmem_unuse_inode()), it may have been read in earlier from swap, in
|
|
* ignorance of the mapping it belongs to. If that mapping has special
|
|
* constraints (like the gma500 GEM driver, which requires RAM below 4GB),
|
|
* we may need to copy to a suitable page before moving to filecache.
|
|
*
|
|
* In a future release, this may well be extended to respect cpuset and
|
|
* NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
|
|
* but for now it is a simple matter of zone.
|
|
*/
|
|
static bool shmem_should_replace_page(struct page *page, gfp_t gfp)
|
|
{
|
|
return page_zonenum(page) > gfp_zone(gfp);
|
|
}
|
|
|
|
static int shmem_replace_page(struct page **pagep, gfp_t gfp,
|
|
struct shmem_inode_info *info, pgoff_t index)
|
|
{
|
|
struct page *oldpage, *newpage;
|
|
struct address_space *swap_mapping;
|
|
swp_entry_t entry;
|
|
pgoff_t swap_index;
|
|
int error;
|
|
|
|
oldpage = *pagep;
|
|
entry.val = page_private(oldpage);
|
|
swap_index = swp_offset(entry);
|
|
swap_mapping = page_mapping(oldpage);
|
|
|
|
/*
|
|
* We have arrived here because our zones are constrained, so don't
|
|
* limit chance of success by further cpuset and node constraints.
|
|
*/
|
|
gfp &= ~GFP_CONSTRAINT_MASK;
|
|
newpage = shmem_alloc_page(gfp, info, index);
|
|
if (!newpage)
|
|
return -ENOMEM;
|
|
|
|
get_page(newpage);
|
|
copy_highpage(newpage, oldpage);
|
|
flush_dcache_page(newpage);
|
|
|
|
__SetPageLocked(newpage);
|
|
__SetPageSwapBacked(newpage);
|
|
SetPageUptodate(newpage);
|
|
set_page_private(newpage, entry.val);
|
|
SetPageSwapCache(newpage);
|
|
|
|
/*
|
|
* Our caller will very soon move newpage out of swapcache, but it's
|
|
* a nice clean interface for us to replace oldpage by newpage there.
|
|
*/
|
|
xa_lock_irq(&swap_mapping->i_pages);
|
|
error = shmem_replace_entry(swap_mapping, swap_index, oldpage, newpage);
|
|
if (!error) {
|
|
mem_cgroup_migrate(oldpage, newpage);
|
|
__inc_lruvec_page_state(newpage, NR_FILE_PAGES);
|
|
__dec_lruvec_page_state(oldpage, NR_FILE_PAGES);
|
|
}
|
|
xa_unlock_irq(&swap_mapping->i_pages);
|
|
|
|
if (unlikely(error)) {
|
|
/*
|
|
* Is this possible? I think not, now that our callers check
|
|
* both PageSwapCache and page_private after getting page lock;
|
|
* but be defensive. Reverse old to newpage for clear and free.
|
|
*/
|
|
oldpage = newpage;
|
|
} else {
|
|
lru_cache_add(newpage);
|
|
*pagep = newpage;
|
|
}
|
|
|
|
ClearPageSwapCache(oldpage);
|
|
set_page_private(oldpage, 0);
|
|
|
|
unlock_page(oldpage);
|
|
put_page(oldpage);
|
|
put_page(oldpage);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Swap in the page pointed to by *pagep.
|
|
* Caller has to make sure that *pagep contains a valid swapped page.
|
|
* Returns 0 and the page in pagep if success. On failure, returns the
|
|
* error code and NULL in *pagep.
|
|
*/
|
|
static int shmem_swapin_page(struct inode *inode, pgoff_t index,
|
|
struct page **pagep, enum sgp_type sgp,
|
|
gfp_t gfp, struct vm_area_struct *vma,
|
|
vm_fault_t *fault_type)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct mm_struct *charge_mm = vma ? vma->vm_mm : current->mm;
|
|
struct page *page;
|
|
swp_entry_t swap;
|
|
int error;
|
|
|
|
VM_BUG_ON(!*pagep || !xa_is_value(*pagep));
|
|
swap = radix_to_swp_entry(*pagep);
|
|
*pagep = NULL;
|
|
|
|
/* Look it up and read it in.. */
|
|
page = lookup_swap_cache(swap, NULL, 0);
|
|
if (!page) {
|
|
/* Or update major stats only when swapin succeeds?? */
|
|
if (fault_type) {
|
|
*fault_type |= VM_FAULT_MAJOR;
|
|
count_vm_event(PGMAJFAULT);
|
|
count_memcg_event_mm(charge_mm, PGMAJFAULT);
|
|
}
|
|
/* Here we actually start the io */
|
|
page = shmem_swapin(swap, gfp, info, index);
|
|
if (!page) {
|
|
error = -ENOMEM;
|
|
goto failed;
|
|
}
|
|
}
|
|
|
|
/* We have to do this with page locked to prevent races */
|
|
lock_page(page);
|
|
if (!PageSwapCache(page) || page_private(page) != swap.val ||
|
|
!shmem_confirm_swap(mapping, index, swap)) {
|
|
error = -EEXIST;
|
|
goto unlock;
|
|
}
|
|
if (!PageUptodate(page)) {
|
|
error = -EIO;
|
|
goto failed;
|
|
}
|
|
wait_on_page_writeback(page);
|
|
|
|
/*
|
|
* Some architectures may have to restore extra metadata to the
|
|
* physical page after reading from swap.
|
|
*/
|
|
arch_swap_restore(swap, page);
|
|
|
|
if (shmem_should_replace_page(page, gfp)) {
|
|
error = shmem_replace_page(&page, gfp, info, index);
|
|
if (error)
|
|
goto failed;
|
|
}
|
|
|
|
error = shmem_add_to_page_cache(page, mapping, index,
|
|
swp_to_radix_entry(swap), gfp,
|
|
charge_mm);
|
|
if (error)
|
|
goto failed;
|
|
|
|
spin_lock_irq(&info->lock);
|
|
info->swapped--;
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
|
|
if (sgp == SGP_WRITE)
|
|
mark_page_accessed(page);
|
|
|
|
delete_from_swap_cache(page);
|
|
set_page_dirty(page);
|
|
swap_free(swap);
|
|
|
|
*pagep = page;
|
|
return 0;
|
|
failed:
|
|
if (!shmem_confirm_swap(mapping, index, swap))
|
|
error = -EEXIST;
|
|
unlock:
|
|
if (page) {
|
|
unlock_page(page);
|
|
put_page(page);
|
|
}
|
|
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* shmem_getpage_gfp - find page in cache, or get from swap, or allocate
|
|
*
|
|
* If we allocate a new one we do not mark it dirty. That's up to the
|
|
* vm. If we swap it in we mark it dirty since we also free the swap
|
|
* entry since a page cannot live in both the swap and page cache.
|
|
*
|
|
* vmf and fault_type are only supplied by shmem_fault:
|
|
* otherwise they are NULL.
|
|
*/
|
|
static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
|
|
struct page **pagep, enum sgp_type sgp, gfp_t gfp,
|
|
struct vm_area_struct *vma, struct vm_fault *vmf,
|
|
vm_fault_t *fault_type)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_sb_info *sbinfo;
|
|
struct mm_struct *charge_mm;
|
|
struct page *page;
|
|
enum sgp_type sgp_huge = sgp;
|
|
pgoff_t hindex = index;
|
|
gfp_t huge_gfp;
|
|
int error;
|
|
int once = 0;
|
|
int alloced = 0;
|
|
|
|
if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT))
|
|
return -EFBIG;
|
|
if (sgp == SGP_NOHUGE || sgp == SGP_HUGE)
|
|
sgp = SGP_CACHE;
|
|
repeat:
|
|
if (sgp <= SGP_CACHE &&
|
|
((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
sbinfo = SHMEM_SB(inode->i_sb);
|
|
charge_mm = vma ? vma->vm_mm : current->mm;
|
|
|
|
page = pagecache_get_page(mapping, index,
|
|
FGP_ENTRY | FGP_HEAD | FGP_LOCK, 0);
|
|
if (xa_is_value(page)) {
|
|
error = shmem_swapin_page(inode, index, &page,
|
|
sgp, gfp, vma, fault_type);
|
|
if (error == -EEXIST)
|
|
goto repeat;
|
|
|
|
*pagep = page;
|
|
return error;
|
|
}
|
|
|
|
if (page)
|
|
hindex = page->index;
|
|
if (page && sgp == SGP_WRITE)
|
|
mark_page_accessed(page);
|
|
|
|
/* fallocated page? */
|
|
if (page && !PageUptodate(page)) {
|
|
if (sgp != SGP_READ)
|
|
goto clear;
|
|
unlock_page(page);
|
|
put_page(page);
|
|
page = NULL;
|
|
hindex = index;
|
|
}
|
|
if (page || sgp == SGP_READ)
|
|
goto out;
|
|
|
|
/*
|
|
* Fast cache lookup did not find it:
|
|
* bring it back from swap or allocate.
|
|
*/
|
|
|
|
if (vma && userfaultfd_missing(vma)) {
|
|
*fault_type = handle_userfault(vmf, VM_UFFD_MISSING);
|
|
return 0;
|
|
}
|
|
|
|
/* shmem_symlink() */
|
|
if (!shmem_mapping(mapping))
|
|
goto alloc_nohuge;
|
|
if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE)
|
|
goto alloc_nohuge;
|
|
if (shmem_huge == SHMEM_HUGE_FORCE)
|
|
goto alloc_huge;
|
|
switch (sbinfo->huge) {
|
|
case SHMEM_HUGE_NEVER:
|
|
goto alloc_nohuge;
|
|
case SHMEM_HUGE_WITHIN_SIZE: {
|
|
loff_t i_size;
|
|
pgoff_t off;
|
|
|
|
off = round_up(index, HPAGE_PMD_NR);
|
|
i_size = round_up(i_size_read(inode), PAGE_SIZE);
|
|
if (i_size >= HPAGE_PMD_SIZE &&
|
|
i_size >> PAGE_SHIFT >= off)
|
|
goto alloc_huge;
|
|
|
|
fallthrough;
|
|
}
|
|
case SHMEM_HUGE_ADVISE:
|
|
if (sgp_huge == SGP_HUGE)
|
|
goto alloc_huge;
|
|
/* TODO: implement fadvise() hints */
|
|
goto alloc_nohuge;
|
|
}
|
|
|
|
alloc_huge:
|
|
huge_gfp = vma_thp_gfp_mask(vma);
|
|
huge_gfp = limit_gfp_mask(huge_gfp, gfp);
|
|
page = shmem_alloc_and_acct_page(huge_gfp, inode, index, true);
|
|
if (IS_ERR(page)) {
|
|
alloc_nohuge:
|
|
page = shmem_alloc_and_acct_page(gfp, inode,
|
|
index, false);
|
|
}
|
|
if (IS_ERR(page)) {
|
|
int retry = 5;
|
|
|
|
error = PTR_ERR(page);
|
|
page = NULL;
|
|
if (error != -ENOSPC)
|
|
goto unlock;
|
|
/*
|
|
* Try to reclaim some space by splitting a huge page
|
|
* beyond i_size on the filesystem.
|
|
*/
|
|
while (retry--) {
|
|
int ret;
|
|
|
|
ret = shmem_unused_huge_shrink(sbinfo, NULL, 1);
|
|
if (ret == SHRINK_STOP)
|
|
break;
|
|
if (ret)
|
|
goto alloc_nohuge;
|
|
}
|
|
goto unlock;
|
|
}
|
|
|
|
if (PageTransHuge(page))
|
|
hindex = round_down(index, HPAGE_PMD_NR);
|
|
else
|
|
hindex = index;
|
|
|
|
if (sgp == SGP_WRITE)
|
|
__SetPageReferenced(page);
|
|
|
|
error = shmem_add_to_page_cache(page, mapping, hindex,
|
|
NULL, gfp & GFP_RECLAIM_MASK,
|
|
charge_mm);
|
|
if (error)
|
|
goto unacct;
|
|
lru_cache_add(page);
|
|
|
|
spin_lock_irq(&info->lock);
|
|
info->alloced += compound_nr(page);
|
|
inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
alloced = true;
|
|
|
|
if (PageTransHuge(page) &&
|
|
DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) <
|
|
hindex + HPAGE_PMD_NR - 1) {
|
|
/*
|
|
* Part of the huge page is beyond i_size: subject
|
|
* to shrink under memory pressure.
|
|
*/
|
|
spin_lock(&sbinfo->shrinklist_lock);
|
|
/*
|
|
* _careful to defend against unlocked access to
|
|
* ->shrink_list in shmem_unused_huge_shrink()
|
|
*/
|
|
if (list_empty_careful(&info->shrinklist)) {
|
|
list_add_tail(&info->shrinklist,
|
|
&sbinfo->shrinklist);
|
|
sbinfo->shrinklist_len++;
|
|
}
|
|
spin_unlock(&sbinfo->shrinklist_lock);
|
|
}
|
|
|
|
/*
|
|
* Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
|
|
*/
|
|
if (sgp == SGP_FALLOC)
|
|
sgp = SGP_WRITE;
|
|
clear:
|
|
/*
|
|
* Let SGP_WRITE caller clear ends if write does not fill page;
|
|
* but SGP_FALLOC on a page fallocated earlier must initialize
|
|
* it now, lest undo on failure cancel our earlier guarantee.
|
|
*/
|
|
if (sgp != SGP_WRITE && !PageUptodate(page)) {
|
|
int i;
|
|
|
|
for (i = 0; i < compound_nr(page); i++) {
|
|
clear_highpage(page + i);
|
|
flush_dcache_page(page + i);
|
|
}
|
|
SetPageUptodate(page);
|
|
}
|
|
|
|
/* Perhaps the file has been truncated since we checked */
|
|
if (sgp <= SGP_CACHE &&
|
|
((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) {
|
|
if (alloced) {
|
|
ClearPageDirty(page);
|
|
delete_from_page_cache(page);
|
|
spin_lock_irq(&info->lock);
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
}
|
|
error = -EINVAL;
|
|
goto unlock;
|
|
}
|
|
out:
|
|
*pagep = page + index - hindex;
|
|
return 0;
|
|
|
|
/*
|
|
* Error recovery.
|
|
*/
|
|
unacct:
|
|
shmem_inode_unacct_blocks(inode, compound_nr(page));
|
|
|
|
if (PageTransHuge(page)) {
|
|
unlock_page(page);
|
|
put_page(page);
|
|
goto alloc_nohuge;
|
|
}
|
|
unlock:
|
|
if (page) {
|
|
unlock_page(page);
|
|
put_page(page);
|
|
}
|
|
if (error == -ENOSPC && !once++) {
|
|
spin_lock_irq(&info->lock);
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
goto repeat;
|
|
}
|
|
if (error == -EEXIST)
|
|
goto repeat;
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* This is like autoremove_wake_function, but it removes the wait queue
|
|
* entry unconditionally - even if something else had already woken the
|
|
* target.
|
|
*/
|
|
static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
|
|
{
|
|
int ret = default_wake_function(wait, mode, sync, key);
|
|
list_del_init(&wait->entry);
|
|
return ret;
|
|
}
|
|
|
|
static vm_fault_t shmem_fault(struct vm_fault *vmf)
|
|
{
|
|
struct vm_area_struct *vma = vmf->vma;
|
|
struct inode *inode = file_inode(vma->vm_file);
|
|
gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
|
|
enum sgp_type sgp;
|
|
int err;
|
|
vm_fault_t ret = VM_FAULT_LOCKED;
|
|
|
|
/*
|
|
* Trinity finds that probing a hole which tmpfs is punching can
|
|
* prevent the hole-punch from ever completing: which in turn
|
|
* locks writers out with its hold on i_mutex. So refrain from
|
|
* faulting pages into the hole while it's being punched. Although
|
|
* shmem_undo_range() does remove the additions, it may be unable to
|
|
* keep up, as each new page needs its own unmap_mapping_range() call,
|
|
* and the i_mmap tree grows ever slower to scan if new vmas are added.
|
|
*
|
|
* It does not matter if we sometimes reach this check just before the
|
|
* hole-punch begins, so that one fault then races with the punch:
|
|
* we just need to make racing faults a rare case.
|
|
*
|
|
* The implementation below would be much simpler if we just used a
|
|
* standard mutex or completion: but we cannot take i_mutex in fault,
|
|
* and bloating every shmem inode for this unlikely case would be sad.
|
|
*/
|
|
if (unlikely(inode->i_private)) {
|
|
struct shmem_falloc *shmem_falloc;
|
|
|
|
spin_lock(&inode->i_lock);
|
|
shmem_falloc = inode->i_private;
|
|
if (shmem_falloc &&
|
|
shmem_falloc->waitq &&
|
|
vmf->pgoff >= shmem_falloc->start &&
|
|
vmf->pgoff < shmem_falloc->next) {
|
|
struct file *fpin;
|
|
wait_queue_head_t *shmem_falloc_waitq;
|
|
DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function);
|
|
|
|
ret = VM_FAULT_NOPAGE;
|
|
fpin = maybe_unlock_mmap_for_io(vmf, NULL);
|
|
if (fpin)
|
|
ret = VM_FAULT_RETRY;
|
|
|
|
shmem_falloc_waitq = shmem_falloc->waitq;
|
|
prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
spin_unlock(&inode->i_lock);
|
|
schedule();
|
|
|
|
/*
|
|
* shmem_falloc_waitq points into the shmem_fallocate()
|
|
* stack of the hole-punching task: shmem_falloc_waitq
|
|
* is usually invalid by the time we reach here, but
|
|
* finish_wait() does not dereference it in that case;
|
|
* though i_lock needed lest racing with wake_up_all().
|
|
*/
|
|
spin_lock(&inode->i_lock);
|
|
finish_wait(shmem_falloc_waitq, &shmem_fault_wait);
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
if (fpin)
|
|
fput(fpin);
|
|
return ret;
|
|
}
|
|
spin_unlock(&inode->i_lock);
|
|
}
|
|
|
|
sgp = SGP_CACHE;
|
|
|
|
if ((vma->vm_flags & VM_NOHUGEPAGE) ||
|
|
test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
|
|
sgp = SGP_NOHUGE;
|
|
else if (vma->vm_flags & VM_HUGEPAGE)
|
|
sgp = SGP_HUGE;
|
|
|
|
err = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp,
|
|
gfp, vma, vmf, &ret);
|
|
if (err)
|
|
return vmf_error(err);
|
|
return ret;
|
|
}
|
|
|
|
unsigned long shmem_get_unmapped_area(struct file *file,
|
|
unsigned long uaddr, unsigned long len,
|
|
unsigned long pgoff, unsigned long flags)
|
|
{
|
|
unsigned long (*get_area)(struct file *,
|
|
unsigned long, unsigned long, unsigned long, unsigned long);
|
|
unsigned long addr;
|
|
unsigned long offset;
|
|
unsigned long inflated_len;
|
|
unsigned long inflated_addr;
|
|
unsigned long inflated_offset;
|
|
|
|
if (len > TASK_SIZE)
|
|
return -ENOMEM;
|
|
|
|
get_area = current->mm->get_unmapped_area;
|
|
addr = get_area(file, uaddr, len, pgoff, flags);
|
|
|
|
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
|
|
return addr;
|
|
if (IS_ERR_VALUE(addr))
|
|
return addr;
|
|
if (addr & ~PAGE_MASK)
|
|
return addr;
|
|
if (addr > TASK_SIZE - len)
|
|
return addr;
|
|
|
|
if (shmem_huge == SHMEM_HUGE_DENY)
|
|
return addr;
|
|
if (len < HPAGE_PMD_SIZE)
|
|
return addr;
|
|
if (flags & MAP_FIXED)
|
|
return addr;
|
|
/*
|
|
* Our priority is to support MAP_SHARED mapped hugely;
|
|
* and support MAP_PRIVATE mapped hugely too, until it is COWed.
|
|
* But if caller specified an address hint and we allocated area there
|
|
* successfully, respect that as before.
|
|
*/
|
|
if (uaddr == addr)
|
|
return addr;
|
|
|
|
if (shmem_huge != SHMEM_HUGE_FORCE) {
|
|
struct super_block *sb;
|
|
|
|
if (file) {
|
|
VM_BUG_ON(file->f_op != &shmem_file_operations);
|
|
sb = file_inode(file)->i_sb;
|
|
} else {
|
|
/*
|
|
* Called directly from mm/mmap.c, or drivers/char/mem.c
|
|
* for "/dev/zero", to create a shared anonymous object.
|
|
*/
|
|
if (IS_ERR(shm_mnt))
|
|
return addr;
|
|
sb = shm_mnt->mnt_sb;
|
|
}
|
|
if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER)
|
|
return addr;
|
|
}
|
|
|
|
offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
|
|
if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
|
|
return addr;
|
|
if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
|
|
return addr;
|
|
|
|
inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
|
|
if (inflated_len > TASK_SIZE)
|
|
return addr;
|
|
if (inflated_len < len)
|
|
return addr;
|
|
|
|
inflated_addr = get_area(NULL, uaddr, inflated_len, 0, flags);
|
|
if (IS_ERR_VALUE(inflated_addr))
|
|
return addr;
|
|
if (inflated_addr & ~PAGE_MASK)
|
|
return addr;
|
|
|
|
inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
|
|
inflated_addr += offset - inflated_offset;
|
|
if (inflated_offset > offset)
|
|
inflated_addr += HPAGE_PMD_SIZE;
|
|
|
|
if (inflated_addr > TASK_SIZE - len)
|
|
return addr;
|
|
return inflated_addr;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
|
|
{
|
|
struct inode *inode = file_inode(vma->vm_file);
|
|
return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol);
|
|
}
|
|
|
|
static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
|
|
unsigned long addr)
|
|
{
|
|
struct inode *inode = file_inode(vma->vm_file);
|
|
pgoff_t index;
|
|
|
|
index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
|
|
return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index);
|
|
}
|
|
#endif
|
|
|
|
int shmem_lock(struct file *file, int lock, struct user_struct *user)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
int retval = -ENOMEM;
|
|
|
|
/*
|
|
* What serializes the accesses to info->flags?
|
|
* ipc_lock_object() when called from shmctl_do_lock(),
|
|
* no serialization needed when called from shm_destroy().
|
|
*/
|
|
if (lock && !(info->flags & VM_LOCKED)) {
|
|
if (!user_shm_lock(inode->i_size, user))
|
|
goto out_nomem;
|
|
info->flags |= VM_LOCKED;
|
|
mapping_set_unevictable(file->f_mapping);
|
|
}
|
|
if (!lock && (info->flags & VM_LOCKED) && user) {
|
|
user_shm_unlock(inode->i_size, user);
|
|
info->flags &= ~VM_LOCKED;
|
|
mapping_clear_unevictable(file->f_mapping);
|
|
}
|
|
retval = 0;
|
|
|
|
out_nomem:
|
|
return retval;
|
|
}
|
|
|
|
static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(file_inode(file));
|
|
|
|
if (info->seals & F_SEAL_FUTURE_WRITE) {
|
|
/*
|
|
* New PROT_WRITE and MAP_SHARED mmaps are not allowed when
|
|
* "future write" seal active.
|
|
*/
|
|
if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_WRITE))
|
|
return -EPERM;
|
|
|
|
/*
|
|
* Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
|
|
* MAP_SHARED and read-only, take care to not allow mprotect to
|
|
* revert protections on such mappings. Do this only for shared
|
|
* mappings. For private mappings, don't need to mask
|
|
* VM_MAYWRITE as we still want them to be COW-writable.
|
|
*/
|
|
if (vma->vm_flags & VM_SHARED)
|
|
vma->vm_flags &= ~(VM_MAYWRITE);
|
|
}
|
|
|
|
/* arm64 - allow memory tagging on RAM-based files */
|
|
vma->vm_flags |= VM_MTE_ALLOWED;
|
|
|
|
file_accessed(file);
|
|
vma->vm_ops = &shmem_vm_ops;
|
|
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
|
|
((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
|
|
(vma->vm_end & HPAGE_PMD_MASK)) {
|
|
khugepaged_enter(vma, vma->vm_flags);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir,
|
|
umode_t mode, dev_t dev, unsigned long flags)
|
|
{
|
|
struct inode *inode;
|
|
struct shmem_inode_info *info;
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
ino_t ino;
|
|
|
|
if (shmem_reserve_inode(sb, &ino))
|
|
return NULL;
|
|
|
|
inode = new_inode(sb);
|
|
if (inode) {
|
|
inode->i_ino = ino;
|
|
inode_init_owner(&init_user_ns, inode, dir, mode);
|
|
inode->i_blocks = 0;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
|
|
inode->i_generation = prandom_u32();
|
|
info = SHMEM_I(inode);
|
|
memset(info, 0, (char *)inode - (char *)info);
|
|
spin_lock_init(&info->lock);
|
|
atomic_set(&info->stop_eviction, 0);
|
|
info->seals = F_SEAL_SEAL;
|
|
info->flags = flags & VM_NORESERVE;
|
|
INIT_LIST_HEAD(&info->shrinklist);
|
|
INIT_LIST_HEAD(&info->swaplist);
|
|
simple_xattrs_init(&info->xattrs);
|
|
cache_no_acl(inode);
|
|
|
|
switch (mode & S_IFMT) {
|
|
default:
|
|
inode->i_op = &shmem_special_inode_operations;
|
|
init_special_inode(inode, mode, dev);
|
|
break;
|
|
case S_IFREG:
|
|
inode->i_mapping->a_ops = &shmem_aops;
|
|
inode->i_op = &shmem_inode_operations;
|
|
inode->i_fop = &shmem_file_operations;
|
|
mpol_shared_policy_init(&info->policy,
|
|
shmem_get_sbmpol(sbinfo));
|
|
break;
|
|
case S_IFDIR:
|
|
inc_nlink(inode);
|
|
/* Some things misbehave if size == 0 on a directory */
|
|
inode->i_size = 2 * BOGO_DIRENT_SIZE;
|
|
inode->i_op = &shmem_dir_inode_operations;
|
|
inode->i_fop = &simple_dir_operations;
|
|
break;
|
|
case S_IFLNK:
|
|
/*
|
|
* Must not load anything in the rbtree,
|
|
* mpol_free_shared_policy will not be called.
|
|
*/
|
|
mpol_shared_policy_init(&info->policy, NULL);
|
|
break;
|
|
}
|
|
|
|
lockdep_annotate_inode_mutex_key(inode);
|
|
} else
|
|
shmem_free_inode(sb);
|
|
return inode;
|
|
}
|
|
|
|
static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr,
|
|
unsigned long src_addr,
|
|
bool zeropage,
|
|
struct page **pagep)
|
|
{
|
|
struct inode *inode = file_inode(dst_vma->vm_file);
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct address_space *mapping = inode->i_mapping;
|
|
gfp_t gfp = mapping_gfp_mask(mapping);
|
|
pgoff_t pgoff = linear_page_index(dst_vma, dst_addr);
|
|
spinlock_t *ptl;
|
|
void *page_kaddr;
|
|
struct page *page;
|
|
pte_t _dst_pte, *dst_pte;
|
|
int ret;
|
|
pgoff_t offset, max_off;
|
|
|
|
ret = -ENOMEM;
|
|
if (!shmem_inode_acct_block(inode, 1))
|
|
goto out;
|
|
|
|
if (!*pagep) {
|
|
page = shmem_alloc_page(gfp, info, pgoff);
|
|
if (!page)
|
|
goto out_unacct_blocks;
|
|
|
|
if (!zeropage) { /* mcopy_atomic */
|
|
page_kaddr = kmap_atomic(page);
|
|
ret = copy_from_user(page_kaddr,
|
|
(const void __user *)src_addr,
|
|
PAGE_SIZE);
|
|
kunmap_atomic(page_kaddr);
|
|
|
|
/* fallback to copy_from_user outside mmap_lock */
|
|
if (unlikely(ret)) {
|
|
*pagep = page;
|
|
shmem_inode_unacct_blocks(inode, 1);
|
|
/* don't free the page */
|
|
return -ENOENT;
|
|
}
|
|
} else { /* mfill_zeropage_atomic */
|
|
clear_highpage(page);
|
|
}
|
|
} else {
|
|
page = *pagep;
|
|
*pagep = NULL;
|
|
}
|
|
|
|
VM_BUG_ON(PageLocked(page) || PageSwapBacked(page));
|
|
__SetPageLocked(page);
|
|
__SetPageSwapBacked(page);
|
|
__SetPageUptodate(page);
|
|
|
|
ret = -EFAULT;
|
|
offset = linear_page_index(dst_vma, dst_addr);
|
|
max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
|
|
if (unlikely(offset >= max_off))
|
|
goto out_release;
|
|
|
|
ret = shmem_add_to_page_cache(page, mapping, pgoff, NULL,
|
|
gfp & GFP_RECLAIM_MASK, dst_mm);
|
|
if (ret)
|
|
goto out_release;
|
|
|
|
_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
|
|
if (dst_vma->vm_flags & VM_WRITE)
|
|
_dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
|
|
else {
|
|
/*
|
|
* We don't set the pte dirty if the vma has no
|
|
* VM_WRITE permission, so mark the page dirty or it
|
|
* could be freed from under us. We could do it
|
|
* unconditionally before unlock_page(), but doing it
|
|
* only if VM_WRITE is not set is faster.
|
|
*/
|
|
set_page_dirty(page);
|
|
}
|
|
|
|
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
|
|
|
|
ret = -EFAULT;
|
|
max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
|
|
if (unlikely(offset >= max_off))
|
|
goto out_release_unlock;
|
|
|
|
ret = -EEXIST;
|
|
if (!pte_none(*dst_pte))
|
|
goto out_release_unlock;
|
|
|
|
lru_cache_add(page);
|
|
|
|
spin_lock_irq(&info->lock);
|
|
info->alloced++;
|
|
inode->i_blocks += BLOCKS_PER_PAGE;
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock_irq(&info->lock);
|
|
|
|
inc_mm_counter(dst_mm, mm_counter_file(page));
|
|
page_add_file_rmap(page, false);
|
|
set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
|
|
|
|
/* No need to invalidate - it was non-present before */
|
|
update_mmu_cache(dst_vma, dst_addr, dst_pte);
|
|
pte_unmap_unlock(dst_pte, ptl);
|
|
unlock_page(page);
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
out_release_unlock:
|
|
pte_unmap_unlock(dst_pte, ptl);
|
|
ClearPageDirty(page);
|
|
delete_from_page_cache(page);
|
|
out_release:
|
|
unlock_page(page);
|
|
put_page(page);
|
|
out_unacct_blocks:
|
|
shmem_inode_unacct_blocks(inode, 1);
|
|
goto out;
|
|
}
|
|
|
|
int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr,
|
|
unsigned long src_addr,
|
|
struct page **pagep)
|
|
{
|
|
return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
|
|
dst_addr, src_addr, false, pagep);
|
|
}
|
|
|
|
int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm,
|
|
pmd_t *dst_pmd,
|
|
struct vm_area_struct *dst_vma,
|
|
unsigned long dst_addr)
|
|
{
|
|
struct page *page = NULL;
|
|
|
|
return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
|
|
dst_addr, 0, true, &page);
|
|
}
|
|
|
|
#ifdef CONFIG_TMPFS
|
|
static const struct inode_operations shmem_symlink_inode_operations;
|
|
static const struct inode_operations shmem_short_symlink_operations;
|
|
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
|
|
#else
|
|
#define shmem_initxattrs NULL
|
|
#endif
|
|
|
|
static int
|
|
shmem_write_begin(struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned flags,
|
|
struct page **pagep, void **fsdata)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
pgoff_t index = pos >> PAGE_SHIFT;
|
|
|
|
/* i_mutex is held by caller */
|
|
if (unlikely(info->seals & (F_SEAL_GROW |
|
|
F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) {
|
|
if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))
|
|
return -EPERM;
|
|
if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size)
|
|
return -EPERM;
|
|
}
|
|
|
|
return shmem_getpage(inode, index, pagep, SGP_WRITE);
|
|
}
|
|
|
|
static int
|
|
shmem_write_end(struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
|
|
if (pos + copied > inode->i_size)
|
|
i_size_write(inode, pos + copied);
|
|
|
|
if (!PageUptodate(page)) {
|
|
struct page *head = compound_head(page);
|
|
if (PageTransCompound(page)) {
|
|
int i;
|
|
|
|
for (i = 0; i < HPAGE_PMD_NR; i++) {
|
|
if (head + i == page)
|
|
continue;
|
|
clear_highpage(head + i);
|
|
flush_dcache_page(head + i);
|
|
}
|
|
}
|
|
if (copied < PAGE_SIZE) {
|
|
unsigned from = pos & (PAGE_SIZE - 1);
|
|
zero_user_segments(page, 0, from,
|
|
from + copied, PAGE_SIZE);
|
|
}
|
|
SetPageUptodate(head);
|
|
}
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
|
|
return copied;
|
|
}
|
|
|
|
static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct inode *inode = file_inode(file);
|
|
struct address_space *mapping = inode->i_mapping;
|
|
pgoff_t index;
|
|
unsigned long offset;
|
|
enum sgp_type sgp = SGP_READ;
|
|
int error = 0;
|
|
ssize_t retval = 0;
|
|
loff_t *ppos = &iocb->ki_pos;
|
|
|
|
/*
|
|
* Might this read be for a stacking filesystem? Then when reading
|
|
* holes of a sparse file, we actually need to allocate those pages,
|
|
* and even mark them dirty, so it cannot exceed the max_blocks limit.
|
|
*/
|
|
if (!iter_is_iovec(to))
|
|
sgp = SGP_CACHE;
|
|
|
|
index = *ppos >> PAGE_SHIFT;
|
|
offset = *ppos & ~PAGE_MASK;
|
|
|
|
for (;;) {
|
|
struct page *page = NULL;
|
|
pgoff_t end_index;
|
|
unsigned long nr, ret;
|
|
loff_t i_size = i_size_read(inode);
|
|
|
|
end_index = i_size >> PAGE_SHIFT;
|
|
if (index > end_index)
|
|
break;
|
|
if (index == end_index) {
|
|
nr = i_size & ~PAGE_MASK;
|
|
if (nr <= offset)
|
|
break;
|
|
}
|
|
|
|
error = shmem_getpage(inode, index, &page, sgp);
|
|
if (error) {
|
|
if (error == -EINVAL)
|
|
error = 0;
|
|
break;
|
|
}
|
|
if (page) {
|
|
if (sgp == SGP_CACHE)
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
}
|
|
|
|
/*
|
|
* We must evaluate after, since reads (unlike writes)
|
|
* are called without i_mutex protection against truncate
|
|
*/
|
|
nr = PAGE_SIZE;
|
|
i_size = i_size_read(inode);
|
|
end_index = i_size >> PAGE_SHIFT;
|
|
if (index == end_index) {
|
|
nr = i_size & ~PAGE_MASK;
|
|
if (nr <= offset) {
|
|
if (page)
|
|
put_page(page);
|
|
break;
|
|
}
|
|
}
|
|
nr -= offset;
|
|
|
|
if (page) {
|
|
/*
|
|
* If users can be writing to this page using arbitrary
|
|
* virtual addresses, take care about potential aliasing
|
|
* before reading the page on the kernel side.
|
|
*/
|
|
if (mapping_writably_mapped(mapping))
|
|
flush_dcache_page(page);
|
|
/*
|
|
* Mark the page accessed if we read the beginning.
|
|
*/
|
|
if (!offset)
|
|
mark_page_accessed(page);
|
|
} else {
|
|
page = ZERO_PAGE(0);
|
|
get_page(page);
|
|
}
|
|
|
|
/*
|
|
* Ok, we have the page, and it's up-to-date, so
|
|
* now we can copy it to user space...
|
|
*/
|
|
ret = copy_page_to_iter(page, offset, nr, to);
|
|
retval += ret;
|
|
offset += ret;
|
|
index += offset >> PAGE_SHIFT;
|
|
offset &= ~PAGE_MASK;
|
|
|
|
put_page(page);
|
|
if (!iov_iter_count(to))
|
|
break;
|
|
if (ret < nr) {
|
|
error = -EFAULT;
|
|
break;
|
|
}
|
|
cond_resched();
|
|
}
|
|
|
|
*ppos = ((loff_t) index << PAGE_SHIFT) + offset;
|
|
file_accessed(file);
|
|
return retval ? retval : error;
|
|
}
|
|
|
|
static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence)
|
|
{
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
|
|
if (whence != SEEK_DATA && whence != SEEK_HOLE)
|
|
return generic_file_llseek_size(file, offset, whence,
|
|
MAX_LFS_FILESIZE, i_size_read(inode));
|
|
if (offset < 0)
|
|
return -ENXIO;
|
|
|
|
inode_lock(inode);
|
|
/* We're holding i_mutex so we can access i_size directly */
|
|
offset = mapping_seek_hole_data(mapping, offset, inode->i_size, whence);
|
|
if (offset >= 0)
|
|
offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE);
|
|
inode_unlock(inode);
|
|
return offset;
|
|
}
|
|
|
|
static long shmem_fallocate(struct file *file, int mode, loff_t offset,
|
|
loff_t len)
|
|
{
|
|
struct inode *inode = file_inode(file);
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_falloc shmem_falloc;
|
|
pgoff_t start, index, end;
|
|
int error;
|
|
|
|
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
|
|
return -EOPNOTSUPP;
|
|
|
|
inode_lock(inode);
|
|
|
|
if (mode & FALLOC_FL_PUNCH_HOLE) {
|
|
struct address_space *mapping = file->f_mapping;
|
|
loff_t unmap_start = round_up(offset, PAGE_SIZE);
|
|
loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1;
|
|
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq);
|
|
|
|
/* protected by i_mutex */
|
|
if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) {
|
|
error = -EPERM;
|
|
goto out;
|
|
}
|
|
|
|
shmem_falloc.waitq = &shmem_falloc_waitq;
|
|
shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT;
|
|
shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_private = &shmem_falloc;
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
if ((u64)unmap_end > (u64)unmap_start)
|
|
unmap_mapping_range(mapping, unmap_start,
|
|
1 + unmap_end - unmap_start, 0);
|
|
shmem_truncate_range(inode, offset, offset + len - 1);
|
|
/* No need to unmap again: hole-punching leaves COWed pages */
|
|
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_private = NULL;
|
|
wake_up_all(&shmem_falloc_waitq);
|
|
WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.head));
|
|
spin_unlock(&inode->i_lock);
|
|
error = 0;
|
|
goto out;
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
|
|
start = offset >> PAGE_SHIFT;
|
|
end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
/* Try to avoid a swapstorm if len is impossible to satisfy */
|
|
if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) {
|
|
error = -ENOSPC;
|
|
goto out;
|
|
}
|
|
|
|
shmem_falloc.waitq = NULL;
|
|
shmem_falloc.start = start;
|
|
shmem_falloc.next = start;
|
|
shmem_falloc.nr_falloced = 0;
|
|
shmem_falloc.nr_unswapped = 0;
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_private = &shmem_falloc;
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
for (index = start; index < end; index++) {
|
|
struct page *page;
|
|
|
|
/*
|
|
* Good, the fallocate(2) manpage permits EINTR: we may have
|
|
* been interrupted because we are using up too much memory.
|
|
*/
|
|
if (signal_pending(current))
|
|
error = -EINTR;
|
|
else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced)
|
|
error = -ENOMEM;
|
|
else
|
|
error = shmem_getpage(inode, index, &page, SGP_FALLOC);
|
|
if (error) {
|
|
/* Remove the !PageUptodate pages we added */
|
|
if (index > start) {
|
|
shmem_undo_range(inode,
|
|
(loff_t)start << PAGE_SHIFT,
|
|
((loff_t)index << PAGE_SHIFT) - 1, true);
|
|
}
|
|
goto undone;
|
|
}
|
|
|
|
/*
|
|
* Inform shmem_writepage() how far we have reached.
|
|
* No need for lock or barrier: we have the page lock.
|
|
*/
|
|
shmem_falloc.next++;
|
|
if (!PageUptodate(page))
|
|
shmem_falloc.nr_falloced++;
|
|
|
|
/*
|
|
* If !PageUptodate, leave it that way so that freeable pages
|
|
* can be recognized if we need to rollback on error later.
|
|
* But set_page_dirty so that memory pressure will swap rather
|
|
* than free the pages we are allocating (and SGP_CACHE pages
|
|
* might still be clean: we now need to mark those dirty too).
|
|
*/
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
cond_resched();
|
|
}
|
|
|
|
if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size)
|
|
i_size_write(inode, offset + len);
|
|
inode->i_ctime = current_time(inode);
|
|
undone:
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_private = NULL;
|
|
spin_unlock(&inode->i_lock);
|
|
out:
|
|
inode_unlock(inode);
|
|
return error;
|
|
}
|
|
|
|
static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
|
|
|
|
buf->f_type = TMPFS_MAGIC;
|
|
buf->f_bsize = PAGE_SIZE;
|
|
buf->f_namelen = NAME_MAX;
|
|
if (sbinfo->max_blocks) {
|
|
buf->f_blocks = sbinfo->max_blocks;
|
|
buf->f_bavail =
|
|
buf->f_bfree = sbinfo->max_blocks -
|
|
percpu_counter_sum(&sbinfo->used_blocks);
|
|
}
|
|
if (sbinfo->max_inodes) {
|
|
buf->f_files = sbinfo->max_inodes;
|
|
buf->f_ffree = sbinfo->free_inodes;
|
|
}
|
|
/* else leave those fields 0 like simple_statfs */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* File creation. Allocate an inode, and we're done..
|
|
*/
|
|
static int
|
|
shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, umode_t mode, dev_t dev)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
|
|
inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
|
|
if (inode) {
|
|
error = simple_acl_create(dir, inode);
|
|
if (error)
|
|
goto out_iput;
|
|
error = security_inode_init_security(inode, dir,
|
|
&dentry->d_name,
|
|
shmem_initxattrs, NULL);
|
|
if (error && error != -EOPNOTSUPP)
|
|
goto out_iput;
|
|
|
|
error = 0;
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
dir->i_ctime = dir->i_mtime = current_time(dir);
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
}
|
|
return error;
|
|
out_iput:
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
|
|
static int
|
|
shmem_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, umode_t mode)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
|
|
inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE);
|
|
if (inode) {
|
|
error = security_inode_init_security(inode, dir,
|
|
NULL,
|
|
shmem_initxattrs, NULL);
|
|
if (error && error != -EOPNOTSUPP)
|
|
goto out_iput;
|
|
error = simple_acl_create(dir, inode);
|
|
if (error)
|
|
goto out_iput;
|
|
d_tmpfile(dentry, inode);
|
|
}
|
|
return error;
|
|
out_iput:
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
|
|
static int shmem_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, umode_t mode)
|
|
{
|
|
int error;
|
|
|
|
if ((error = shmem_mknod(&init_user_ns, dir, dentry,
|
|
mode | S_IFDIR, 0)))
|
|
return error;
|
|
inc_nlink(dir);
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_create(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, umode_t mode, bool excl)
|
|
{
|
|
return shmem_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
|
|
}
|
|
|
|
/*
|
|
* Link a file..
|
|
*/
|
|
static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
|
|
{
|
|
struct inode *inode = d_inode(old_dentry);
|
|
int ret = 0;
|
|
|
|
/*
|
|
* No ordinary (disk based) filesystem counts links as inodes;
|
|
* but each new link needs a new dentry, pinning lowmem, and
|
|
* tmpfs dentries cannot be pruned until they are unlinked.
|
|
* But if an O_TMPFILE file is linked into the tmpfs, the
|
|
* first link must skip that, to get the accounting right.
|
|
*/
|
|
if (inode->i_nlink) {
|
|
ret = shmem_reserve_inode(inode->i_sb, NULL);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
|
|
inc_nlink(inode);
|
|
ihold(inode); /* New dentry reference */
|
|
dget(dentry); /* Extra pinning count for the created dentry */
|
|
d_instantiate(dentry, inode);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int shmem_unlink(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
|
|
if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
|
|
shmem_free_inode(inode->i_sb);
|
|
|
|
dir->i_size -= BOGO_DIRENT_SIZE;
|
|
inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
|
|
drop_nlink(inode);
|
|
dput(dentry); /* Undo the count from "create" - this does all the work */
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
|
|
{
|
|
if (!simple_empty(dentry))
|
|
return -ENOTEMPTY;
|
|
|
|
drop_nlink(d_inode(dentry));
|
|
drop_nlink(dir);
|
|
return shmem_unlink(dir, dentry);
|
|
}
|
|
|
|
static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
|
|
{
|
|
bool old_is_dir = d_is_dir(old_dentry);
|
|
bool new_is_dir = d_is_dir(new_dentry);
|
|
|
|
if (old_dir != new_dir && old_is_dir != new_is_dir) {
|
|
if (old_is_dir) {
|
|
drop_nlink(old_dir);
|
|
inc_nlink(new_dir);
|
|
} else {
|
|
drop_nlink(new_dir);
|
|
inc_nlink(old_dir);
|
|
}
|
|
}
|
|
old_dir->i_ctime = old_dir->i_mtime =
|
|
new_dir->i_ctime = new_dir->i_mtime =
|
|
d_inode(old_dentry)->i_ctime =
|
|
d_inode(new_dentry)->i_ctime = current_time(old_dir);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_whiteout(struct user_namespace *mnt_userns,
|
|
struct inode *old_dir, struct dentry *old_dentry)
|
|
{
|
|
struct dentry *whiteout;
|
|
int error;
|
|
|
|
whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
|
|
if (!whiteout)
|
|
return -ENOMEM;
|
|
|
|
error = shmem_mknod(&init_user_ns, old_dir, whiteout,
|
|
S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
|
|
dput(whiteout);
|
|
if (error)
|
|
return error;
|
|
|
|
/*
|
|
* Cheat and hash the whiteout while the old dentry is still in
|
|
* place, instead of playing games with FS_RENAME_DOES_D_MOVE.
|
|
*
|
|
* d_lookup() will consistently find one of them at this point,
|
|
* not sure which one, but that isn't even important.
|
|
*/
|
|
d_rehash(whiteout);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* The VFS layer already does all the dentry stuff for rename,
|
|
* we just have to decrement the usage count for the target if
|
|
* it exists so that the VFS layer correctly free's it when it
|
|
* gets overwritten.
|
|
*/
|
|
static int shmem_rename2(struct user_namespace *mnt_userns,
|
|
struct inode *old_dir, struct dentry *old_dentry,
|
|
struct inode *new_dir, struct dentry *new_dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct inode *inode = d_inode(old_dentry);
|
|
int they_are_dirs = S_ISDIR(inode->i_mode);
|
|
|
|
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
|
|
return -EINVAL;
|
|
|
|
if (flags & RENAME_EXCHANGE)
|
|
return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry);
|
|
|
|
if (!simple_empty(new_dentry))
|
|
return -ENOTEMPTY;
|
|
|
|
if (flags & RENAME_WHITEOUT) {
|
|
int error;
|
|
|
|
error = shmem_whiteout(&init_user_ns, old_dir, old_dentry);
|
|
if (error)
|
|
return error;
|
|
}
|
|
|
|
if (d_really_is_positive(new_dentry)) {
|
|
(void) shmem_unlink(new_dir, new_dentry);
|
|
if (they_are_dirs) {
|
|
drop_nlink(d_inode(new_dentry));
|
|
drop_nlink(old_dir);
|
|
}
|
|
} else if (they_are_dirs) {
|
|
drop_nlink(old_dir);
|
|
inc_nlink(new_dir);
|
|
}
|
|
|
|
old_dir->i_size -= BOGO_DIRENT_SIZE;
|
|
new_dir->i_size += BOGO_DIRENT_SIZE;
|
|
old_dir->i_ctime = old_dir->i_mtime =
|
|
new_dir->i_ctime = new_dir->i_mtime =
|
|
inode->i_ctime = current_time(old_dir);
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
|
|
struct dentry *dentry, const char *symname)
|
|
{
|
|
int error;
|
|
int len;
|
|
struct inode *inode;
|
|
struct page *page;
|
|
|
|
len = strlen(symname) + 1;
|
|
if (len > PAGE_SIZE)
|
|
return -ENAMETOOLONG;
|
|
|
|
inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK | 0777, 0,
|
|
VM_NORESERVE);
|
|
if (!inode)
|
|
return -ENOSPC;
|
|
|
|
error = security_inode_init_security(inode, dir, &dentry->d_name,
|
|
shmem_initxattrs, NULL);
|
|
if (error && error != -EOPNOTSUPP) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
|
|
inode->i_size = len-1;
|
|
if (len <= SHORT_SYMLINK_LEN) {
|
|
inode->i_link = kmemdup(symname, len, GFP_KERNEL);
|
|
if (!inode->i_link) {
|
|
iput(inode);
|
|
return -ENOMEM;
|
|
}
|
|
inode->i_op = &shmem_short_symlink_operations;
|
|
} else {
|
|
inode_nohighmem(inode);
|
|
error = shmem_getpage(inode, 0, &page, SGP_WRITE);
|
|
if (error) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
inode->i_mapping->a_ops = &shmem_aops;
|
|
inode->i_op = &shmem_symlink_inode_operations;
|
|
memcpy(page_address(page), symname, len);
|
|
SetPageUptodate(page);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
put_page(page);
|
|
}
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
dir->i_ctime = dir->i_mtime = current_time(dir);
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
return 0;
|
|
}
|
|
|
|
static void shmem_put_link(void *arg)
|
|
{
|
|
mark_page_accessed(arg);
|
|
put_page(arg);
|
|
}
|
|
|
|
static const char *shmem_get_link(struct dentry *dentry,
|
|
struct inode *inode,
|
|
struct delayed_call *done)
|
|
{
|
|
struct page *page = NULL;
|
|
int error;
|
|
if (!dentry) {
|
|
page = find_get_page(inode->i_mapping, 0);
|
|
if (!page)
|
|
return ERR_PTR(-ECHILD);
|
|
if (!PageUptodate(page)) {
|
|
put_page(page);
|
|
return ERR_PTR(-ECHILD);
|
|
}
|
|
} else {
|
|
error = shmem_getpage(inode, 0, &page, SGP_READ);
|
|
if (error)
|
|
return ERR_PTR(error);
|
|
unlock_page(page);
|
|
}
|
|
set_delayed_call(done, shmem_put_link, page);
|
|
return page_address(page);
|
|
}
|
|
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
/*
|
|
* Superblocks without xattr inode operations may get some security.* xattr
|
|
* support from the LSM "for free". As soon as we have any other xattrs
|
|
* like ACLs, we also need to implement the security.* handlers at
|
|
* filesystem level, though.
|
|
*/
|
|
|
|
/*
|
|
* Callback for security_inode_init_security() for acquiring xattrs.
|
|
*/
|
|
static int shmem_initxattrs(struct inode *inode,
|
|
const struct xattr *xattr_array,
|
|
void *fs_info)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
const struct xattr *xattr;
|
|
struct simple_xattr *new_xattr;
|
|
size_t len;
|
|
|
|
for (xattr = xattr_array; xattr->name != NULL; xattr++) {
|
|
new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len);
|
|
if (!new_xattr)
|
|
return -ENOMEM;
|
|
|
|
len = strlen(xattr->name) + 1;
|
|
new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len,
|
|
GFP_KERNEL);
|
|
if (!new_xattr->name) {
|
|
kvfree(new_xattr);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
memcpy(new_xattr->name, XATTR_SECURITY_PREFIX,
|
|
XATTR_SECURITY_PREFIX_LEN);
|
|
memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN,
|
|
xattr->name, len);
|
|
|
|
simple_xattr_list_add(&info->xattrs, new_xattr);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_xattr_handler_get(const struct xattr_handler *handler,
|
|
struct dentry *unused, struct inode *inode,
|
|
const char *name, void *buffer, size_t size)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
|
|
name = xattr_full_name(handler, name);
|
|
return simple_xattr_get(&info->xattrs, name, buffer, size);
|
|
}
|
|
|
|
static int shmem_xattr_handler_set(const struct xattr_handler *handler,
|
|
struct user_namespace *mnt_userns,
|
|
struct dentry *unused, struct inode *inode,
|
|
const char *name, const void *value,
|
|
size_t size, int flags)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
|
|
name = xattr_full_name(handler, name);
|
|
return simple_xattr_set(&info->xattrs, name, value, size, flags, NULL);
|
|
}
|
|
|
|
static const struct xattr_handler shmem_security_xattr_handler = {
|
|
.prefix = XATTR_SECURITY_PREFIX,
|
|
.get = shmem_xattr_handler_get,
|
|
.set = shmem_xattr_handler_set,
|
|
};
|
|
|
|
static const struct xattr_handler shmem_trusted_xattr_handler = {
|
|
.prefix = XATTR_TRUSTED_PREFIX,
|
|
.get = shmem_xattr_handler_get,
|
|
.set = shmem_xattr_handler_set,
|
|
};
|
|
|
|
static const struct xattr_handler *shmem_xattr_handlers[] = {
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
&posix_acl_access_xattr_handler,
|
|
&posix_acl_default_xattr_handler,
|
|
#endif
|
|
&shmem_security_xattr_handler,
|
|
&shmem_trusted_xattr_handler,
|
|
NULL
|
|
};
|
|
|
|
static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(d_inode(dentry));
|
|
return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size);
|
|
}
|
|
#endif /* CONFIG_TMPFS_XATTR */
|
|
|
|
static const struct inode_operations shmem_short_symlink_operations = {
|
|
.get_link = simple_get_link,
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
.listxattr = shmem_listxattr,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_symlink_inode_operations = {
|
|
.get_link = shmem_get_link,
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
.listxattr = shmem_listxattr,
|
|
#endif
|
|
};
|
|
|
|
static struct dentry *shmem_get_parent(struct dentry *child)
|
|
{
|
|
return ERR_PTR(-ESTALE);
|
|
}
|
|
|
|
static int shmem_match(struct inode *ino, void *vfh)
|
|
{
|
|
__u32 *fh = vfh;
|
|
__u64 inum = fh[2];
|
|
inum = (inum << 32) | fh[1];
|
|
return ino->i_ino == inum && fh[0] == ino->i_generation;
|
|
}
|
|
|
|
/* Find any alias of inode, but prefer a hashed alias */
|
|
static struct dentry *shmem_find_alias(struct inode *inode)
|
|
{
|
|
struct dentry *alias = d_find_alias(inode);
|
|
|
|
return alias ?: d_find_any_alias(inode);
|
|
}
|
|
|
|
|
|
static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
|
|
struct fid *fid, int fh_len, int fh_type)
|
|
{
|
|
struct inode *inode;
|
|
struct dentry *dentry = NULL;
|
|
u64 inum;
|
|
|
|
if (fh_len < 3)
|
|
return NULL;
|
|
|
|
inum = fid->raw[2];
|
|
inum = (inum << 32) | fid->raw[1];
|
|
|
|
inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
|
|
shmem_match, fid->raw);
|
|
if (inode) {
|
|
dentry = shmem_find_alias(inode);
|
|
iput(inode);
|
|
}
|
|
|
|
return dentry;
|
|
}
|
|
|
|
static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len,
|
|
struct inode *parent)
|
|
{
|
|
if (*len < 3) {
|
|
*len = 3;
|
|
return FILEID_INVALID;
|
|
}
|
|
|
|
if (inode_unhashed(inode)) {
|
|
/* Unfortunately insert_inode_hash is not idempotent,
|
|
* so as we hash inodes here rather than at creation
|
|
* time, we need a lock to ensure we only try
|
|
* to do it once
|
|
*/
|
|
static DEFINE_SPINLOCK(lock);
|
|
spin_lock(&lock);
|
|
if (inode_unhashed(inode))
|
|
__insert_inode_hash(inode,
|
|
inode->i_ino + inode->i_generation);
|
|
spin_unlock(&lock);
|
|
}
|
|
|
|
fh[0] = inode->i_generation;
|
|
fh[1] = inode->i_ino;
|
|
fh[2] = ((__u64)inode->i_ino) >> 32;
|
|
|
|
*len = 3;
|
|
return 1;
|
|
}
|
|
|
|
static const struct export_operations shmem_export_ops = {
|
|
.get_parent = shmem_get_parent,
|
|
.encode_fh = shmem_encode_fh,
|
|
.fh_to_dentry = shmem_fh_to_dentry,
|
|
};
|
|
|
|
enum shmem_param {
|
|
Opt_gid,
|
|
Opt_huge,
|
|
Opt_mode,
|
|
Opt_mpol,
|
|
Opt_nr_blocks,
|
|
Opt_nr_inodes,
|
|
Opt_size,
|
|
Opt_uid,
|
|
Opt_inode32,
|
|
Opt_inode64,
|
|
};
|
|
|
|
static const struct constant_table shmem_param_enums_huge[] = {
|
|
{"never", SHMEM_HUGE_NEVER },
|
|
{"always", SHMEM_HUGE_ALWAYS },
|
|
{"within_size", SHMEM_HUGE_WITHIN_SIZE },
|
|
{"advise", SHMEM_HUGE_ADVISE },
|
|
{}
|
|
};
|
|
|
|
const struct fs_parameter_spec shmem_fs_parameters[] = {
|
|
fsparam_u32 ("gid", Opt_gid),
|
|
fsparam_enum ("huge", Opt_huge, shmem_param_enums_huge),
|
|
fsparam_u32oct("mode", Opt_mode),
|
|
fsparam_string("mpol", Opt_mpol),
|
|
fsparam_string("nr_blocks", Opt_nr_blocks),
|
|
fsparam_string("nr_inodes", Opt_nr_inodes),
|
|
fsparam_string("size", Opt_size),
|
|
fsparam_u32 ("uid", Opt_uid),
|
|
fsparam_flag ("inode32", Opt_inode32),
|
|
fsparam_flag ("inode64", Opt_inode64),
|
|
{}
|
|
};
|
|
|
|
static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
|
|
{
|
|
struct shmem_options *ctx = fc->fs_private;
|
|
struct fs_parse_result result;
|
|
unsigned long long size;
|
|
char *rest;
|
|
int opt;
|
|
|
|
opt = fs_parse(fc, shmem_fs_parameters, param, &result);
|
|
if (opt < 0)
|
|
return opt;
|
|
|
|
switch (opt) {
|
|
case Opt_size:
|
|
size = memparse(param->string, &rest);
|
|
if (*rest == '%') {
|
|
size <<= PAGE_SHIFT;
|
|
size *= totalram_pages();
|
|
do_div(size, 100);
|
|
rest++;
|
|
}
|
|
if (*rest)
|
|
goto bad_value;
|
|
ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE);
|
|
ctx->seen |= SHMEM_SEEN_BLOCKS;
|
|
break;
|
|
case Opt_nr_blocks:
|
|
ctx->blocks = memparse(param->string, &rest);
|
|
if (*rest)
|
|
goto bad_value;
|
|
ctx->seen |= SHMEM_SEEN_BLOCKS;
|
|
break;
|
|
case Opt_nr_inodes:
|
|
ctx->inodes = memparse(param->string, &rest);
|
|
if (*rest)
|
|
goto bad_value;
|
|
ctx->seen |= SHMEM_SEEN_INODES;
|
|
break;
|
|
case Opt_mode:
|
|
ctx->mode = result.uint_32 & 07777;
|
|
break;
|
|
case Opt_uid:
|
|
ctx->uid = make_kuid(current_user_ns(), result.uint_32);
|
|
if (!uid_valid(ctx->uid))
|
|
goto bad_value;
|
|
break;
|
|
case Opt_gid:
|
|
ctx->gid = make_kgid(current_user_ns(), result.uint_32);
|
|
if (!gid_valid(ctx->gid))
|
|
goto bad_value;
|
|
break;
|
|
case Opt_huge:
|
|
ctx->huge = result.uint_32;
|
|
if (ctx->huge != SHMEM_HUGE_NEVER &&
|
|
!(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
|
|
has_transparent_hugepage()))
|
|
goto unsupported_parameter;
|
|
ctx->seen |= SHMEM_SEEN_HUGE;
|
|
break;
|
|
case Opt_mpol:
|
|
if (IS_ENABLED(CONFIG_NUMA)) {
|
|
mpol_put(ctx->mpol);
|
|
ctx->mpol = NULL;
|
|
if (mpol_parse_str(param->string, &ctx->mpol))
|
|
goto bad_value;
|
|
break;
|
|
}
|
|
goto unsupported_parameter;
|
|
case Opt_inode32:
|
|
ctx->full_inums = false;
|
|
ctx->seen |= SHMEM_SEEN_INUMS;
|
|
break;
|
|
case Opt_inode64:
|
|
if (sizeof(ino_t) < 8) {
|
|
return invalfc(fc,
|
|
"Cannot use inode64 with <64bit inums in kernel\n");
|
|
}
|
|
ctx->full_inums = true;
|
|
ctx->seen |= SHMEM_SEEN_INUMS;
|
|
break;
|
|
}
|
|
return 0;
|
|
|
|
unsupported_parameter:
|
|
return invalfc(fc, "Unsupported parameter '%s'", param->key);
|
|
bad_value:
|
|
return invalfc(fc, "Bad value for '%s'", param->key);
|
|
}
|
|
|
|
static int shmem_parse_options(struct fs_context *fc, void *data)
|
|
{
|
|
char *options = data;
|
|
|
|
if (options) {
|
|
int err = security_sb_eat_lsm_opts(options, &fc->security);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
while (options != NULL) {
|
|
char *this_char = options;
|
|
for (;;) {
|
|
/*
|
|
* NUL-terminate this option: unfortunately,
|
|
* mount options form a comma-separated list,
|
|
* but mpol's nodelist may also contain commas.
|
|
*/
|
|
options = strchr(options, ',');
|
|
if (options == NULL)
|
|
break;
|
|
options++;
|
|
if (!isdigit(*options)) {
|
|
options[-1] = '\0';
|
|
break;
|
|
}
|
|
}
|
|
if (*this_char) {
|
|
char *value = strchr(this_char,'=');
|
|
size_t len = 0;
|
|
int err;
|
|
|
|
if (value) {
|
|
*value++ = '\0';
|
|
len = strlen(value);
|
|
}
|
|
err = vfs_parse_fs_string(fc, this_char, value, len);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Reconfigure a shmem filesystem.
|
|
*
|
|
* Note that we disallow change from limited->unlimited blocks/inodes while any
|
|
* are in use; but we must separately disallow unlimited->limited, because in
|
|
* that case we have no record of how much is already in use.
|
|
*/
|
|
static int shmem_reconfigure(struct fs_context *fc)
|
|
{
|
|
struct shmem_options *ctx = fc->fs_private;
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb);
|
|
unsigned long inodes;
|
|
const char *err;
|
|
|
|
spin_lock(&sbinfo->stat_lock);
|
|
inodes = sbinfo->max_inodes - sbinfo->free_inodes;
|
|
if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) {
|
|
if (!sbinfo->max_blocks) {
|
|
err = "Cannot retroactively limit size";
|
|
goto out;
|
|
}
|
|
if (percpu_counter_compare(&sbinfo->used_blocks,
|
|
ctx->blocks) > 0) {
|
|
err = "Too small a size for current use";
|
|
goto out;
|
|
}
|
|
}
|
|
if ((ctx->seen & SHMEM_SEEN_INODES) && ctx->inodes) {
|
|
if (!sbinfo->max_inodes) {
|
|
err = "Cannot retroactively limit inodes";
|
|
goto out;
|
|
}
|
|
if (ctx->inodes < inodes) {
|
|
err = "Too few inodes for current use";
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
if ((ctx->seen & SHMEM_SEEN_INUMS) && !ctx->full_inums &&
|
|
sbinfo->next_ino > UINT_MAX) {
|
|
err = "Current inum too high to switch to 32-bit inums";
|
|
goto out;
|
|
}
|
|
|
|
if (ctx->seen & SHMEM_SEEN_HUGE)
|
|
sbinfo->huge = ctx->huge;
|
|
if (ctx->seen & SHMEM_SEEN_INUMS)
|
|
sbinfo->full_inums = ctx->full_inums;
|
|
if (ctx->seen & SHMEM_SEEN_BLOCKS)
|
|
sbinfo->max_blocks = ctx->blocks;
|
|
if (ctx->seen & SHMEM_SEEN_INODES) {
|
|
sbinfo->max_inodes = ctx->inodes;
|
|
sbinfo->free_inodes = ctx->inodes - inodes;
|
|
}
|
|
|
|
/*
|
|
* Preserve previous mempolicy unless mpol remount option was specified.
|
|
*/
|
|
if (ctx->mpol) {
|
|
mpol_put(sbinfo->mpol);
|
|
sbinfo->mpol = ctx->mpol; /* transfers initial ref */
|
|
ctx->mpol = NULL;
|
|
}
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
return 0;
|
|
out:
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
return invalfc(fc, "%s", err);
|
|
}
|
|
|
|
static int shmem_show_options(struct seq_file *seq, struct dentry *root)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb);
|
|
|
|
if (sbinfo->max_blocks != shmem_default_max_blocks())
|
|
seq_printf(seq, ",size=%luk",
|
|
sbinfo->max_blocks << (PAGE_SHIFT - 10));
|
|
if (sbinfo->max_inodes != shmem_default_max_inodes())
|
|
seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
|
|
if (sbinfo->mode != (0777 | S_ISVTX))
|
|
seq_printf(seq, ",mode=%03ho", sbinfo->mode);
|
|
if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID))
|
|
seq_printf(seq, ",uid=%u",
|
|
from_kuid_munged(&init_user_ns, sbinfo->uid));
|
|
if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID))
|
|
seq_printf(seq, ",gid=%u",
|
|
from_kgid_munged(&init_user_ns, sbinfo->gid));
|
|
|
|
/*
|
|
* Showing inode{64,32} might be useful even if it's the system default,
|
|
* since then people don't have to resort to checking both here and
|
|
* /proc/config.gz to confirm 64-bit inums were successfully applied
|
|
* (which may not even exist if IKCONFIG_PROC isn't enabled).
|
|
*
|
|
* We hide it when inode64 isn't the default and we are using 32-bit
|
|
* inodes, since that probably just means the feature isn't even under
|
|
* consideration.
|
|
*
|
|
* As such:
|
|
*
|
|
* +-----------------+-----------------+
|
|
* | TMPFS_INODE64=y | TMPFS_INODE64=n |
|
|
* +------------------+-----------------+-----------------+
|
|
* | full_inums=true | show | show |
|
|
* | full_inums=false | show | hide |
|
|
* +------------------+-----------------+-----------------+
|
|
*
|
|
*/
|
|
if (IS_ENABLED(CONFIG_TMPFS_INODE64) || sbinfo->full_inums)
|
|
seq_printf(seq, ",inode%d", (sbinfo->full_inums ? 64 : 32));
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
/* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
|
|
if (sbinfo->huge)
|
|
seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge));
|
|
#endif
|
|
shmem_show_mpol(seq, sbinfo->mpol);
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_TMPFS */
|
|
|
|
static void shmem_put_super(struct super_block *sb)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
|
|
free_percpu(sbinfo->ino_batch);
|
|
percpu_counter_destroy(&sbinfo->used_blocks);
|
|
mpol_put(sbinfo->mpol);
|
|
kfree(sbinfo);
|
|
sb->s_fs_info = NULL;
|
|
}
|
|
|
|
static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
|
|
{
|
|
struct shmem_options *ctx = fc->fs_private;
|
|
struct inode *inode;
|
|
struct shmem_sb_info *sbinfo;
|
|
int err = -ENOMEM;
|
|
|
|
/* Round up to L1_CACHE_BYTES to resist false sharing */
|
|
sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info),
|
|
L1_CACHE_BYTES), GFP_KERNEL);
|
|
if (!sbinfo)
|
|
return -ENOMEM;
|
|
|
|
sb->s_fs_info = sbinfo;
|
|
|
|
#ifdef CONFIG_TMPFS
|
|
/*
|
|
* Per default we only allow half of the physical ram per
|
|
* tmpfs instance, limiting inodes to one per page of lowmem;
|
|
* but the internal instance is left unlimited.
|
|
*/
|
|
if (!(sb->s_flags & SB_KERNMOUNT)) {
|
|
if (!(ctx->seen & SHMEM_SEEN_BLOCKS))
|
|
ctx->blocks = shmem_default_max_blocks();
|
|
if (!(ctx->seen & SHMEM_SEEN_INODES))
|
|
ctx->inodes = shmem_default_max_inodes();
|
|
if (!(ctx->seen & SHMEM_SEEN_INUMS))
|
|
ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64);
|
|
} else {
|
|
sb->s_flags |= SB_NOUSER;
|
|
}
|
|
sb->s_export_op = &shmem_export_ops;
|
|
sb->s_flags |= SB_NOSEC;
|
|
#else
|
|
sb->s_flags |= SB_NOUSER;
|
|
#endif
|
|
sbinfo->max_blocks = ctx->blocks;
|
|
sbinfo->free_inodes = sbinfo->max_inodes = ctx->inodes;
|
|
if (sb->s_flags & SB_KERNMOUNT) {
|
|
sbinfo->ino_batch = alloc_percpu(ino_t);
|
|
if (!sbinfo->ino_batch)
|
|
goto failed;
|
|
}
|
|
sbinfo->uid = ctx->uid;
|
|
sbinfo->gid = ctx->gid;
|
|
sbinfo->full_inums = ctx->full_inums;
|
|
sbinfo->mode = ctx->mode;
|
|
sbinfo->huge = ctx->huge;
|
|
sbinfo->mpol = ctx->mpol;
|
|
ctx->mpol = NULL;
|
|
|
|
spin_lock_init(&sbinfo->stat_lock);
|
|
if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL))
|
|
goto failed;
|
|
spin_lock_init(&sbinfo->shrinklist_lock);
|
|
INIT_LIST_HEAD(&sbinfo->shrinklist);
|
|
|
|
sb->s_maxbytes = MAX_LFS_FILESIZE;
|
|
sb->s_blocksize = PAGE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_SHIFT;
|
|
sb->s_magic = TMPFS_MAGIC;
|
|
sb->s_op = &shmem_ops;
|
|
sb->s_time_gran = 1;
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
sb->s_xattr = shmem_xattr_handlers;
|
|
#endif
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
sb->s_flags |= SB_POSIXACL;
|
|
#endif
|
|
uuid_gen(&sb->s_uuid);
|
|
|
|
inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
|
|
if (!inode)
|
|
goto failed;
|
|
inode->i_uid = sbinfo->uid;
|
|
inode->i_gid = sbinfo->gid;
|
|
sb->s_root = d_make_root(inode);
|
|
if (!sb->s_root)
|
|
goto failed;
|
|
return 0;
|
|
|
|
failed:
|
|
shmem_put_super(sb);
|
|
return err;
|
|
}
|
|
|
|
static int shmem_get_tree(struct fs_context *fc)
|
|
{
|
|
return get_tree_nodev(fc, shmem_fill_super);
|
|
}
|
|
|
|
static void shmem_free_fc(struct fs_context *fc)
|
|
{
|
|
struct shmem_options *ctx = fc->fs_private;
|
|
|
|
if (ctx) {
|
|
mpol_put(ctx->mpol);
|
|
kfree(ctx);
|
|
}
|
|
}
|
|
|
|
static const struct fs_context_operations shmem_fs_context_ops = {
|
|
.free = shmem_free_fc,
|
|
.get_tree = shmem_get_tree,
|
|
#ifdef CONFIG_TMPFS
|
|
.parse_monolithic = shmem_parse_options,
|
|
.parse_param = shmem_parse_one,
|
|
.reconfigure = shmem_reconfigure,
|
|
#endif
|
|
};
|
|
|
|
static struct kmem_cache *shmem_inode_cachep;
|
|
|
|
static struct inode *shmem_alloc_inode(struct super_block *sb)
|
|
{
|
|
struct shmem_inode_info *info;
|
|
info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
|
|
if (!info)
|
|
return NULL;
|
|
return &info->vfs_inode;
|
|
}
|
|
|
|
static void shmem_free_in_core_inode(struct inode *inode)
|
|
{
|
|
if (S_ISLNK(inode->i_mode))
|
|
kfree(inode->i_link);
|
|
kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
|
|
}
|
|
|
|
static void shmem_destroy_inode(struct inode *inode)
|
|
{
|
|
if (S_ISREG(inode->i_mode))
|
|
mpol_free_shared_policy(&SHMEM_I(inode)->policy);
|
|
}
|
|
|
|
static void shmem_init_inode(void *foo)
|
|
{
|
|
struct shmem_inode_info *info = foo;
|
|
inode_init_once(&info->vfs_inode);
|
|
}
|
|
|
|
static void shmem_init_inodecache(void)
|
|
{
|
|
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
|
|
sizeof(struct shmem_inode_info),
|
|
0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode);
|
|
}
|
|
|
|
static void shmem_destroy_inodecache(void)
|
|
{
|
|
kmem_cache_destroy(shmem_inode_cachep);
|
|
}
|
|
|
|
const struct address_space_operations shmem_aops = {
|
|
.writepage = shmem_writepage,
|
|
.set_page_dirty = __set_page_dirty_no_writeback,
|
|
#ifdef CONFIG_TMPFS
|
|
.write_begin = shmem_write_begin,
|
|
.write_end = shmem_write_end,
|
|
#endif
|
|
#ifdef CONFIG_MIGRATION
|
|
.migratepage = migrate_page,
|
|
#endif
|
|
.error_remove_page = generic_error_remove_page,
|
|
};
|
|
EXPORT_SYMBOL(shmem_aops);
|
|
|
|
static const struct file_operations shmem_file_operations = {
|
|
.mmap = shmem_mmap,
|
|
.get_unmapped_area = shmem_get_unmapped_area,
|
|
#ifdef CONFIG_TMPFS
|
|
.llseek = shmem_file_llseek,
|
|
.read_iter = shmem_file_read_iter,
|
|
.write_iter = generic_file_write_iter,
|
|
.fsync = noop_fsync,
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = iter_file_splice_write,
|
|
.fallocate = shmem_fallocate,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_inode_operations = {
|
|
.getattr = shmem_getattr,
|
|
.setattr = shmem_setattr,
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
.listxattr = shmem_listxattr,
|
|
.set_acl = simple_set_acl,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_dir_inode_operations = {
|
|
#ifdef CONFIG_TMPFS
|
|
.create = shmem_create,
|
|
.lookup = simple_lookup,
|
|
.link = shmem_link,
|
|
.unlink = shmem_unlink,
|
|
.symlink = shmem_symlink,
|
|
.mkdir = shmem_mkdir,
|
|
.rmdir = shmem_rmdir,
|
|
.mknod = shmem_mknod,
|
|
.rename = shmem_rename2,
|
|
.tmpfile = shmem_tmpfile,
|
|
#endif
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
.listxattr = shmem_listxattr,
|
|
#endif
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
.setattr = shmem_setattr,
|
|
.set_acl = simple_set_acl,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_special_inode_operations = {
|
|
#ifdef CONFIG_TMPFS_XATTR
|
|
.listxattr = shmem_listxattr,
|
|
#endif
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
.setattr = shmem_setattr,
|
|
.set_acl = simple_set_acl,
|
|
#endif
|
|
};
|
|
|
|
static const struct super_operations shmem_ops = {
|
|
.alloc_inode = shmem_alloc_inode,
|
|
.free_inode = shmem_free_in_core_inode,
|
|
.destroy_inode = shmem_destroy_inode,
|
|
#ifdef CONFIG_TMPFS
|
|
.statfs = shmem_statfs,
|
|
.show_options = shmem_show_options,
|
|
#endif
|
|
.evict_inode = shmem_evict_inode,
|
|
.drop_inode = generic_delete_inode,
|
|
.put_super = shmem_put_super,
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
.nr_cached_objects = shmem_unused_huge_count,
|
|
.free_cached_objects = shmem_unused_huge_scan,
|
|
#endif
|
|
};
|
|
|
|
static const struct vm_operations_struct shmem_vm_ops = {
|
|
.fault = shmem_fault,
|
|
.map_pages = filemap_map_pages,
|
|
#ifdef CONFIG_NUMA
|
|
.set_policy = shmem_set_policy,
|
|
.get_policy = shmem_get_policy,
|
|
#endif
|
|
};
|
|
|
|
int shmem_init_fs_context(struct fs_context *fc)
|
|
{
|
|
struct shmem_options *ctx;
|
|
|
|
ctx = kzalloc(sizeof(struct shmem_options), GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
|
|
ctx->mode = 0777 | S_ISVTX;
|
|
ctx->uid = current_fsuid();
|
|
ctx->gid = current_fsgid();
|
|
|
|
fc->fs_private = ctx;
|
|
fc->ops = &shmem_fs_context_ops;
|
|
return 0;
|
|
}
|
|
|
|
static struct file_system_type shmem_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "tmpfs",
|
|
.init_fs_context = shmem_init_fs_context,
|
|
#ifdef CONFIG_TMPFS
|
|
.parameters = shmem_fs_parameters,
|
|
#endif
|
|
.kill_sb = kill_litter_super,
|
|
.fs_flags = FS_USERNS_MOUNT | FS_THP_SUPPORT,
|
|
};
|
|
|
|
int __init shmem_init(void)
|
|
{
|
|
int error;
|
|
|
|
shmem_init_inodecache();
|
|
|
|
error = register_filesystem(&shmem_fs_type);
|
|
if (error) {
|
|
pr_err("Could not register tmpfs\n");
|
|
goto out2;
|
|
}
|
|
|
|
shm_mnt = kern_mount(&shmem_fs_type);
|
|
if (IS_ERR(shm_mnt)) {
|
|
error = PTR_ERR(shm_mnt);
|
|
pr_err("Could not kern_mount tmpfs\n");
|
|
goto out1;
|
|
}
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
|
|
SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
|
|
else
|
|
shmem_huge = 0; /* just in case it was patched */
|
|
#endif
|
|
return 0;
|
|
|
|
out1:
|
|
unregister_filesystem(&shmem_fs_type);
|
|
out2:
|
|
shmem_destroy_inodecache();
|
|
shm_mnt = ERR_PTR(error);
|
|
return error;
|
|
}
|
|
|
|
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
|
|
static ssize_t shmem_enabled_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
static const int values[] = {
|
|
SHMEM_HUGE_ALWAYS,
|
|
SHMEM_HUGE_WITHIN_SIZE,
|
|
SHMEM_HUGE_ADVISE,
|
|
SHMEM_HUGE_NEVER,
|
|
SHMEM_HUGE_DENY,
|
|
SHMEM_HUGE_FORCE,
|
|
};
|
|
int len = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(values); i++) {
|
|
len += sysfs_emit_at(buf, len,
|
|
shmem_huge == values[i] ? "%s[%s]" : "%s%s",
|
|
i ? " " : "",
|
|
shmem_format_huge(values[i]));
|
|
}
|
|
|
|
len += sysfs_emit_at(buf, len, "\n");
|
|
|
|
return len;
|
|
}
|
|
|
|
static ssize_t shmem_enabled_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr, const char *buf, size_t count)
|
|
{
|
|
char tmp[16];
|
|
int huge;
|
|
|
|
if (count + 1 > sizeof(tmp))
|
|
return -EINVAL;
|
|
memcpy(tmp, buf, count);
|
|
tmp[count] = '\0';
|
|
if (count && tmp[count - 1] == '\n')
|
|
tmp[count - 1] = '\0';
|
|
|
|
huge = shmem_parse_huge(tmp);
|
|
if (huge == -EINVAL)
|
|
return -EINVAL;
|
|
if (!has_transparent_hugepage() &&
|
|
huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
|
|
return -EINVAL;
|
|
|
|
shmem_huge = huge;
|
|
if (shmem_huge > SHMEM_HUGE_DENY)
|
|
SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
|
|
return count;
|
|
}
|
|
|
|
struct kobj_attribute shmem_enabled_attr =
|
|
__ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store);
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
bool shmem_huge_enabled(struct vm_area_struct *vma)
|
|
{
|
|
struct inode *inode = file_inode(vma->vm_file);
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
|
|
loff_t i_size;
|
|
pgoff_t off;
|
|
|
|
if ((vma->vm_flags & VM_NOHUGEPAGE) ||
|
|
test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
|
|
return false;
|
|
if (shmem_huge == SHMEM_HUGE_FORCE)
|
|
return true;
|
|
if (shmem_huge == SHMEM_HUGE_DENY)
|
|
return false;
|
|
switch (sbinfo->huge) {
|
|
case SHMEM_HUGE_NEVER:
|
|
return false;
|
|
case SHMEM_HUGE_ALWAYS:
|
|
return true;
|
|
case SHMEM_HUGE_WITHIN_SIZE:
|
|
off = round_up(vma->vm_pgoff, HPAGE_PMD_NR);
|
|
i_size = round_up(i_size_read(inode), PAGE_SIZE);
|
|
if (i_size >= HPAGE_PMD_SIZE &&
|
|
i_size >> PAGE_SHIFT >= off)
|
|
return true;
|
|
fallthrough;
|
|
case SHMEM_HUGE_ADVISE:
|
|
/* TODO: implement fadvise() hints */
|
|
return (vma->vm_flags & VM_HUGEPAGE);
|
|
default:
|
|
VM_BUG_ON(1);
|
|
return false;
|
|
}
|
|
}
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
|
|
|
|
#else /* !CONFIG_SHMEM */
|
|
|
|
/*
|
|
* tiny-shmem: simple shmemfs and tmpfs using ramfs code
|
|
*
|
|
* This is intended for small system where the benefits of the full
|
|
* shmem code (swap-backed and resource-limited) are outweighed by
|
|
* their complexity. On systems without swap this code should be
|
|
* effectively equivalent, but much lighter weight.
|
|
*/
|
|
|
|
static struct file_system_type shmem_fs_type = {
|
|
.name = "tmpfs",
|
|
.init_fs_context = ramfs_init_fs_context,
|
|
.parameters = ramfs_fs_parameters,
|
|
.kill_sb = kill_litter_super,
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
};
|
|
|
|
int __init shmem_init(void)
|
|
{
|
|
BUG_ON(register_filesystem(&shmem_fs_type) != 0);
|
|
|
|
shm_mnt = kern_mount(&shmem_fs_type);
|
|
BUG_ON(IS_ERR(shm_mnt));
|
|
|
|
return 0;
|
|
}
|
|
|
|
int shmem_unuse(unsigned int type, bool frontswap,
|
|
unsigned long *fs_pages_to_unuse)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int shmem_lock(struct file *file, int lock, struct user_struct *user)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
void shmem_unlock_mapping(struct address_space *mapping)
|
|
{
|
|
}
|
|
|
|
#ifdef CONFIG_MMU
|
|
unsigned long shmem_get_unmapped_area(struct file *file,
|
|
unsigned long addr, unsigned long len,
|
|
unsigned long pgoff, unsigned long flags)
|
|
{
|
|
return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
|
|
}
|
|
#endif
|
|
|
|
void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
|
|
{
|
|
truncate_inode_pages_range(inode->i_mapping, lstart, lend);
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_truncate_range);
|
|
|
|
#define shmem_vm_ops generic_file_vm_ops
|
|
#define shmem_file_operations ramfs_file_operations
|
|
#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
|
|
#define shmem_acct_size(flags, size) 0
|
|
#define shmem_unacct_size(flags, size) do {} while (0)
|
|
|
|
#endif /* CONFIG_SHMEM */
|
|
|
|
/* common code */
|
|
|
|
static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size,
|
|
unsigned long flags, unsigned int i_flags)
|
|
{
|
|
struct inode *inode;
|
|
struct file *res;
|
|
|
|
if (IS_ERR(mnt))
|
|
return ERR_CAST(mnt);
|
|
|
|
if (size < 0 || size > MAX_LFS_FILESIZE)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
if (shmem_acct_size(flags, size))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
inode = shmem_get_inode(mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0,
|
|
flags);
|
|
if (unlikely(!inode)) {
|
|
shmem_unacct_size(flags, size);
|
|
return ERR_PTR(-ENOSPC);
|
|
}
|
|
inode->i_flags |= i_flags;
|
|
inode->i_size = size;
|
|
clear_nlink(inode); /* It is unlinked */
|
|
res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size));
|
|
if (!IS_ERR(res))
|
|
res = alloc_file_pseudo(inode, mnt, name, O_RDWR,
|
|
&shmem_file_operations);
|
|
if (IS_ERR(res))
|
|
iput(inode);
|
|
return res;
|
|
}
|
|
|
|
/**
|
|
* shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
|
|
* kernel internal. There will be NO LSM permission checks against the
|
|
* underlying inode. So users of this interface must do LSM checks at a
|
|
* higher layer. The users are the big_key and shm implementations. LSM
|
|
* checks are provided at the key or shm level rather than the inode.
|
|
* @name: name for dentry (to be seen in /proc/<pid>/maps
|
|
* @size: size to be set for the file
|
|
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
|
|
*/
|
|
struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags)
|
|
{
|
|
return __shmem_file_setup(shm_mnt, name, size, flags, S_PRIVATE);
|
|
}
|
|
|
|
/**
|
|
* shmem_file_setup - get an unlinked file living in tmpfs
|
|
* @name: name for dentry (to be seen in /proc/<pid>/maps
|
|
* @size: size to be set for the file
|
|
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
|
|
*/
|
|
struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags)
|
|
{
|
|
return __shmem_file_setup(shm_mnt, name, size, flags, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_file_setup);
|
|
|
|
/**
|
|
* shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
|
|
* @mnt: the tmpfs mount where the file will be created
|
|
* @name: name for dentry (to be seen in /proc/<pid>/maps
|
|
* @size: size to be set for the file
|
|
* @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
|
|
*/
|
|
struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, const char *name,
|
|
loff_t size, unsigned long flags)
|
|
{
|
|
return __shmem_file_setup(mnt, name, size, flags, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt);
|
|
|
|
/**
|
|
* shmem_zero_setup - setup a shared anonymous mapping
|
|
* @vma: the vma to be mmapped is prepared by do_mmap
|
|
*/
|
|
int shmem_zero_setup(struct vm_area_struct *vma)
|
|
{
|
|
struct file *file;
|
|
loff_t size = vma->vm_end - vma->vm_start;
|
|
|
|
/*
|
|
* Cloning a new file under mmap_lock leads to a lock ordering conflict
|
|
* between XFS directory reading and selinux: since this file is only
|
|
* accessible to the user through its mapping, use S_PRIVATE flag to
|
|
* bypass file security, in the same way as shmem_kernel_file_setup().
|
|
*/
|
|
file = shmem_kernel_file_setup("dev/zero", size, vma->vm_flags);
|
|
if (IS_ERR(file))
|
|
return PTR_ERR(file);
|
|
|
|
if (vma->vm_file)
|
|
fput(vma->vm_file);
|
|
vma->vm_file = file;
|
|
vma->vm_ops = &shmem_vm_ops;
|
|
|
|
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
|
|
((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
|
|
(vma->vm_end & HPAGE_PMD_MASK)) {
|
|
khugepaged_enter(vma, vma->vm_flags);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
|
|
* @mapping: the page's address_space
|
|
* @index: the page index
|
|
* @gfp: the page allocator flags to use if allocating
|
|
*
|
|
* This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
|
|
* with any new page allocations done using the specified allocation flags.
|
|
* But read_cache_page_gfp() uses the ->readpage() method: which does not
|
|
* suit tmpfs, since it may have pages in swapcache, and needs to find those
|
|
* for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
|
|
*
|
|
* i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
|
|
* with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
|
|
*/
|
|
struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
|
|
pgoff_t index, gfp_t gfp)
|
|
{
|
|
#ifdef CONFIG_SHMEM
|
|
struct inode *inode = mapping->host;
|
|
struct page *page;
|
|
int error;
|
|
|
|
BUG_ON(!shmem_mapping(mapping));
|
|
error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE,
|
|
gfp, NULL, NULL, NULL);
|
|
if (error)
|
|
page = ERR_PTR(error);
|
|
else
|
|
unlock_page(page);
|
|
return page;
|
|
#else
|
|
/*
|
|
* The tiny !SHMEM case uses ramfs without swap
|
|
*/
|
|
return read_cache_page_gfp(mapping, index, gfp);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp);
|