![Hugh Dickins](/assets/img/avatar_default.png)
While we're fiddling with the swap_map values, let's assign a particular value to shmem/tmpfs swap pages: their swap counts are never incremented, and it helps swapoff's try_to_unuse() a little if it can immediately distinguish those pages from process pages. Since we've no use for SWAP_MAP_BAD | COUNT_CONTINUED, we might as well use that 0xbf value for SWAP_MAP_SHMEM. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2703 lines
69 KiB
C
2703 lines
69 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) 2002-2005 Hugh Dickins.
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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/pagemap.h>
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#include <linux/file.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/ima.h>
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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/generic_acl.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/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 <asm/uaccess.h>
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#include <asm/div64.h>
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#include <asm/pgtable.h>
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/*
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* The maximum size of a shmem/tmpfs file is limited by the maximum size of
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* its triple-indirect swap vector - see illustration at shmem_swp_entry().
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*
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* With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel,
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* but one eighth of that on a 64-bit kernel. With 8kB page size, maximum
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* file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel,
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* MAX_LFS_FILESIZE being then more restrictive than swap vector layout.
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*
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* We use / and * instead of shifts in the definitions below, so that the swap
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* vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE.
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*/
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#define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
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#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
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#define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
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#define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT)
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#define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE)
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#define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT))
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#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
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#define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
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/* info->flags needs VM_flags to handle pagein/truncate races efficiently */
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#define SHMEM_PAGEIN VM_READ
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#define SHMEM_TRUNCATE VM_WRITE
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/* Definition to limit shmem_truncate's steps between cond_rescheds */
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#define LATENCY_LIMIT 64
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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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/* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
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enum sgp_type {
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SGP_READ, /* don't exceed i_size, don't allocate page */
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SGP_CACHE, /* don't exceed i_size, may allocate page */
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SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
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SGP_WRITE, /* may exceed i_size, may allocate page */
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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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return min(totalram_pages - totalhigh_pages, totalram_pages / 2);
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}
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#endif
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static int shmem_getpage(struct inode *inode, unsigned long idx,
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struct page **pagep, enum sgp_type sgp, int *type);
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static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
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{
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/*
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* The above definition of ENTRIES_PER_PAGE, and the use of
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* BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
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* might be reconsidered if it ever diverges from PAGE_SIZE.
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*
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* Mobility flags are masked out as swap vectors cannot move
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*/
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return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
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PAGE_CACHE_SHIFT-PAGE_SHIFT);
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}
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static inline void shmem_dir_free(struct page *page)
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{
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__free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
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}
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static struct page **shmem_dir_map(struct page *page)
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{
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return (struct page **)kmap_atomic(page, KM_USER0);
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}
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static inline void shmem_dir_unmap(struct page **dir)
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{
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kunmap_atomic(dir, KM_USER0);
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}
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static swp_entry_t *shmem_swp_map(struct page *page)
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{
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return (swp_entry_t *)kmap_atomic(page, KM_USER1);
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}
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static inline void shmem_swp_balance_unmap(void)
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{
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/*
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* When passing a pointer to an i_direct entry, to code which
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* also handles indirect entries and so will shmem_swp_unmap,
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* we must arrange for the preempt count to remain in balance.
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* What kmap_atomic of a lowmem page does depends on config
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* and architecture, so pretend to kmap_atomic some lowmem page.
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*/
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(void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
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}
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static inline void shmem_swp_unmap(swp_entry_t *entry)
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{
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kunmap_atomic(entry, KM_USER1);
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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_kern(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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/*
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* ... whereas tmpfs objects are accounted incrementally as
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* pages are allocated, in order to allow huge 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)
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{
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return (flags & VM_NORESERVE) ?
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security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0;
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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_CACHE_SIZE));
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}
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static const struct super_operations shmem_ops;
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static 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 backing_dev_info shmem_backing_dev_info __read_mostly = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
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.unplug_io_fn = default_unplug_io_fn,
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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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static void shmem_free_blocks(struct inode *inode, long pages)
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{
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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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spin_lock(&sbinfo->stat_lock);
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sbinfo->free_blocks += pages;
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inode->i_blocks -= pages*BLOCKS_PER_PAGE;
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spin_unlock(&sbinfo->stat_lock);
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}
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}
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static int shmem_reserve_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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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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spin_unlock(&sbinfo->stat_lock);
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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 size 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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shmem_unacct_blocks(info->flags, freed);
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shmem_free_blocks(inode, freed);
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}
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}
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/**
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* shmem_swp_entry - find the swap vector position in the info structure
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* @info: info structure for the inode
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* @index: index of the page to find
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* @page: optional page to add to the structure. Has to be preset to
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* all zeros
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*
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* If there is no space allocated yet it will return NULL when
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* page is NULL, else it will use the page for the needed block,
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* setting it to NULL on return to indicate that it has been used.
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*
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* The swap vector is organized the following way:
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*
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* There are SHMEM_NR_DIRECT entries directly stored in the
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* shmem_inode_info structure. So small files do not need an addional
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* allocation.
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*
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* For pages with index > SHMEM_NR_DIRECT there is the pointer
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* i_indirect which points to a page which holds in the first half
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* doubly indirect blocks, in the second half triple indirect blocks:
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*
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* For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
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* following layout (for SHMEM_NR_DIRECT == 16):
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*
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* i_indirect -> dir --> 16-19
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* | +-> 20-23
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* |
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* +-->dir2 --> 24-27
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* | +-> 28-31
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* | +-> 32-35
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* | +-> 36-39
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* |
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* +-->dir3 --> 40-43
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* +-> 44-47
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* +-> 48-51
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* +-> 52-55
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*/
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static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
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{
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unsigned long offset;
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struct page **dir;
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struct page *subdir;
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if (index < SHMEM_NR_DIRECT) {
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shmem_swp_balance_unmap();
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return info->i_direct+index;
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}
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if (!info->i_indirect) {
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if (page) {
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info->i_indirect = *page;
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*page = NULL;
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}
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return NULL; /* need another page */
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}
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index -= SHMEM_NR_DIRECT;
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offset = index % ENTRIES_PER_PAGE;
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index /= ENTRIES_PER_PAGE;
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dir = shmem_dir_map(info->i_indirect);
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if (index >= ENTRIES_PER_PAGE/2) {
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index -= ENTRIES_PER_PAGE/2;
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dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
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index %= ENTRIES_PER_PAGE;
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subdir = *dir;
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if (!subdir) {
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if (page) {
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*dir = *page;
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*page = NULL;
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}
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shmem_dir_unmap(dir);
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return NULL; /* need another page */
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}
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shmem_dir_unmap(dir);
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dir = shmem_dir_map(subdir);
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}
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dir += index;
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subdir = *dir;
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if (!subdir) {
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if (!page || !(subdir = *page)) {
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shmem_dir_unmap(dir);
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return NULL; /* need a page */
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}
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*dir = subdir;
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*page = NULL;
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}
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shmem_dir_unmap(dir);
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return shmem_swp_map(subdir) + offset;
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}
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static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
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{
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long incdec = value? 1: -1;
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entry->val = value;
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info->swapped += incdec;
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if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
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struct page *page = kmap_atomic_to_page(entry);
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set_page_private(page, page_private(page) + incdec);
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}
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}
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/**
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* shmem_swp_alloc - get the position of the swap entry for the page.
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* @info: info structure for the inode
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* @index: index of the page to find
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* @sgp: check and recheck i_size? skip allocation?
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*
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* If the entry does not exist, allocate it.
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*/
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static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
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{
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struct inode *inode = &info->vfs_inode;
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struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
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struct page *page = NULL;
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swp_entry_t *entry;
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if (sgp != SGP_WRITE &&
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((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
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return ERR_PTR(-EINVAL);
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while (!(entry = shmem_swp_entry(info, index, &page))) {
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if (sgp == SGP_READ)
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return shmem_swp_map(ZERO_PAGE(0));
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/*
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* Test free_blocks against 1 not 0, since we have 1 data
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* page (and perhaps indirect index pages) yet to allocate:
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* a waste to allocate index if we cannot allocate data.
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*/
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if (sbinfo->max_blocks) {
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spin_lock(&sbinfo->stat_lock);
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if (sbinfo->free_blocks <= 1) {
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spin_unlock(&sbinfo->stat_lock);
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return ERR_PTR(-ENOSPC);
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}
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sbinfo->free_blocks--;
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inode->i_blocks += BLOCKS_PER_PAGE;
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spin_unlock(&sbinfo->stat_lock);
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}
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spin_unlock(&info->lock);
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page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
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if (page)
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set_page_private(page, 0);
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spin_lock(&info->lock);
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if (!page) {
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shmem_free_blocks(inode, 1);
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return ERR_PTR(-ENOMEM);
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}
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if (sgp != SGP_WRITE &&
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((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
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entry = ERR_PTR(-EINVAL);
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break;
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}
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if (info->next_index <= index)
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info->next_index = index + 1;
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}
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if (page) {
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/* another task gave its page, or truncated the file */
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shmem_free_blocks(inode, 1);
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shmem_dir_free(page);
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}
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if (info->next_index <= index && !IS_ERR(entry))
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info->next_index = index + 1;
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return entry;
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}
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/**
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* shmem_free_swp - free some swap entries in a directory
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* @dir: pointer to the directory
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* @edir: pointer after last entry of the directory
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* @punch_lock: pointer to spinlock when needed for the holepunch case
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*/
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static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
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spinlock_t *punch_lock)
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{
|
|
spinlock_t *punch_unlock = NULL;
|
|
swp_entry_t *ptr;
|
|
int freed = 0;
|
|
|
|
for (ptr = dir; ptr < edir; ptr++) {
|
|
if (ptr->val) {
|
|
if (unlikely(punch_lock)) {
|
|
punch_unlock = punch_lock;
|
|
punch_lock = NULL;
|
|
spin_lock(punch_unlock);
|
|
if (!ptr->val)
|
|
continue;
|
|
}
|
|
free_swap_and_cache(*ptr);
|
|
*ptr = (swp_entry_t){0};
|
|
freed++;
|
|
}
|
|
}
|
|
if (punch_unlock)
|
|
spin_unlock(punch_unlock);
|
|
return freed;
|
|
}
|
|
|
|
static int shmem_map_and_free_swp(struct page *subdir, int offset,
|
|
int limit, struct page ***dir, spinlock_t *punch_lock)
|
|
{
|
|
swp_entry_t *ptr;
|
|
int freed = 0;
|
|
|
|
ptr = shmem_swp_map(subdir);
|
|
for (; offset < limit; offset += LATENCY_LIMIT) {
|
|
int size = limit - offset;
|
|
if (size > LATENCY_LIMIT)
|
|
size = LATENCY_LIMIT;
|
|
freed += shmem_free_swp(ptr+offset, ptr+offset+size,
|
|
punch_lock);
|
|
if (need_resched()) {
|
|
shmem_swp_unmap(ptr);
|
|
if (*dir) {
|
|
shmem_dir_unmap(*dir);
|
|
*dir = NULL;
|
|
}
|
|
cond_resched();
|
|
ptr = shmem_swp_map(subdir);
|
|
}
|
|
}
|
|
shmem_swp_unmap(ptr);
|
|
return freed;
|
|
}
|
|
|
|
static void shmem_free_pages(struct list_head *next)
|
|
{
|
|
struct page *page;
|
|
int freed = 0;
|
|
|
|
do {
|
|
page = container_of(next, struct page, lru);
|
|
next = next->next;
|
|
shmem_dir_free(page);
|
|
freed++;
|
|
if (freed >= LATENCY_LIMIT) {
|
|
cond_resched();
|
|
freed = 0;
|
|
}
|
|
} while (next);
|
|
}
|
|
|
|
static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
unsigned long idx;
|
|
unsigned long size;
|
|
unsigned long limit;
|
|
unsigned long stage;
|
|
unsigned long diroff;
|
|
struct page **dir;
|
|
struct page *topdir;
|
|
struct page *middir;
|
|
struct page *subdir;
|
|
swp_entry_t *ptr;
|
|
LIST_HEAD(pages_to_free);
|
|
long nr_pages_to_free = 0;
|
|
long nr_swaps_freed = 0;
|
|
int offset;
|
|
int freed;
|
|
int punch_hole;
|
|
spinlock_t *needs_lock;
|
|
spinlock_t *punch_lock;
|
|
unsigned long upper_limit;
|
|
|
|
inode->i_ctime = inode->i_mtime = CURRENT_TIME;
|
|
idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
|
|
if (idx >= info->next_index)
|
|
return;
|
|
|
|
spin_lock(&info->lock);
|
|
info->flags |= SHMEM_TRUNCATE;
|
|
if (likely(end == (loff_t) -1)) {
|
|
limit = info->next_index;
|
|
upper_limit = SHMEM_MAX_INDEX;
|
|
info->next_index = idx;
|
|
needs_lock = NULL;
|
|
punch_hole = 0;
|
|
} else {
|
|
if (end + 1 >= inode->i_size) { /* we may free a little more */
|
|
limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
|
|
PAGE_CACHE_SHIFT;
|
|
upper_limit = SHMEM_MAX_INDEX;
|
|
} else {
|
|
limit = (end + 1) >> PAGE_CACHE_SHIFT;
|
|
upper_limit = limit;
|
|
}
|
|
needs_lock = &info->lock;
|
|
punch_hole = 1;
|
|
}
|
|
|
|
topdir = info->i_indirect;
|
|
if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
|
|
info->i_indirect = NULL;
|
|
nr_pages_to_free++;
|
|
list_add(&topdir->lru, &pages_to_free);
|
|
}
|
|
spin_unlock(&info->lock);
|
|
|
|
if (info->swapped && idx < SHMEM_NR_DIRECT) {
|
|
ptr = info->i_direct;
|
|
size = limit;
|
|
if (size > SHMEM_NR_DIRECT)
|
|
size = SHMEM_NR_DIRECT;
|
|
nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
|
|
}
|
|
|
|
/*
|
|
* If there are no indirect blocks or we are punching a hole
|
|
* below indirect blocks, nothing to be done.
|
|
*/
|
|
if (!topdir || limit <= SHMEM_NR_DIRECT)
|
|
goto done2;
|
|
|
|
/*
|
|
* The truncation case has already dropped info->lock, and we're safe
|
|
* because i_size and next_index have already been lowered, preventing
|
|
* access beyond. But in the punch_hole case, we still need to take
|
|
* the lock when updating the swap directory, because there might be
|
|
* racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
|
|
* shmem_writepage. However, whenever we find we can remove a whole
|
|
* directory page (not at the misaligned start or end of the range),
|
|
* we first NULLify its pointer in the level above, and then have no
|
|
* need to take the lock when updating its contents: needs_lock and
|
|
* punch_lock (either pointing to info->lock or NULL) manage this.
|
|
*/
|
|
|
|
upper_limit -= SHMEM_NR_DIRECT;
|
|
limit -= SHMEM_NR_DIRECT;
|
|
idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
|
|
offset = idx % ENTRIES_PER_PAGE;
|
|
idx -= offset;
|
|
|
|
dir = shmem_dir_map(topdir);
|
|
stage = ENTRIES_PER_PAGEPAGE/2;
|
|
if (idx < ENTRIES_PER_PAGEPAGE/2) {
|
|
middir = topdir;
|
|
diroff = idx/ENTRIES_PER_PAGE;
|
|
} else {
|
|
dir += ENTRIES_PER_PAGE/2;
|
|
dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
|
|
while (stage <= idx)
|
|
stage += ENTRIES_PER_PAGEPAGE;
|
|
middir = *dir;
|
|
if (*dir) {
|
|
diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
|
|
ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
|
|
if (!diroff && !offset && upper_limit >= stage) {
|
|
if (needs_lock) {
|
|
spin_lock(needs_lock);
|
|
*dir = NULL;
|
|
spin_unlock(needs_lock);
|
|
needs_lock = NULL;
|
|
} else
|
|
*dir = NULL;
|
|
nr_pages_to_free++;
|
|
list_add(&middir->lru, &pages_to_free);
|
|
}
|
|
shmem_dir_unmap(dir);
|
|
dir = shmem_dir_map(middir);
|
|
} else {
|
|
diroff = 0;
|
|
offset = 0;
|
|
idx = stage;
|
|
}
|
|
}
|
|
|
|
for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
|
|
if (unlikely(idx == stage)) {
|
|
shmem_dir_unmap(dir);
|
|
dir = shmem_dir_map(topdir) +
|
|
ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
|
|
while (!*dir) {
|
|
dir++;
|
|
idx += ENTRIES_PER_PAGEPAGE;
|
|
if (idx >= limit)
|
|
goto done1;
|
|
}
|
|
stage = idx + ENTRIES_PER_PAGEPAGE;
|
|
middir = *dir;
|
|
if (punch_hole)
|
|
needs_lock = &info->lock;
|
|
if (upper_limit >= stage) {
|
|
if (needs_lock) {
|
|
spin_lock(needs_lock);
|
|
*dir = NULL;
|
|
spin_unlock(needs_lock);
|
|
needs_lock = NULL;
|
|
} else
|
|
*dir = NULL;
|
|
nr_pages_to_free++;
|
|
list_add(&middir->lru, &pages_to_free);
|
|
}
|
|
shmem_dir_unmap(dir);
|
|
cond_resched();
|
|
dir = shmem_dir_map(middir);
|
|
diroff = 0;
|
|
}
|
|
punch_lock = needs_lock;
|
|
subdir = dir[diroff];
|
|
if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
|
|
if (needs_lock) {
|
|
spin_lock(needs_lock);
|
|
dir[diroff] = NULL;
|
|
spin_unlock(needs_lock);
|
|
punch_lock = NULL;
|
|
} else
|
|
dir[diroff] = NULL;
|
|
nr_pages_to_free++;
|
|
list_add(&subdir->lru, &pages_to_free);
|
|
}
|
|
if (subdir && page_private(subdir) /* has swap entries */) {
|
|
size = limit - idx;
|
|
if (size > ENTRIES_PER_PAGE)
|
|
size = ENTRIES_PER_PAGE;
|
|
freed = shmem_map_and_free_swp(subdir,
|
|
offset, size, &dir, punch_lock);
|
|
if (!dir)
|
|
dir = shmem_dir_map(middir);
|
|
nr_swaps_freed += freed;
|
|
if (offset || punch_lock) {
|
|
spin_lock(&info->lock);
|
|
set_page_private(subdir,
|
|
page_private(subdir) - freed);
|
|
spin_unlock(&info->lock);
|
|
} else
|
|
BUG_ON(page_private(subdir) != freed);
|
|
}
|
|
offset = 0;
|
|
}
|
|
done1:
|
|
shmem_dir_unmap(dir);
|
|
done2:
|
|
if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
|
|
/*
|
|
* Call truncate_inode_pages again: racing shmem_unuse_inode
|
|
* may have swizzled a page in from swap since vmtruncate or
|
|
* generic_delete_inode did it, before we lowered next_index.
|
|
* Also, though shmem_getpage checks i_size before adding to
|
|
* cache, no recheck after: so fix the narrow window there too.
|
|
*
|
|
* Recalling truncate_inode_pages_range and unmap_mapping_range
|
|
* every time for punch_hole (which never got a chance to clear
|
|
* SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
|
|
* yet hardly ever necessary: try to optimize them out later.
|
|
*/
|
|
truncate_inode_pages_range(inode->i_mapping, start, end);
|
|
if (punch_hole)
|
|
unmap_mapping_range(inode->i_mapping, start,
|
|
end - start, 1);
|
|
}
|
|
|
|
spin_lock(&info->lock);
|
|
info->flags &= ~SHMEM_TRUNCATE;
|
|
info->swapped -= nr_swaps_freed;
|
|
if (nr_pages_to_free)
|
|
shmem_free_blocks(inode, nr_pages_to_free);
|
|
shmem_recalc_inode(inode);
|
|
spin_unlock(&info->lock);
|
|
|
|
/*
|
|
* Empty swap vector directory pages to be freed?
|
|
*/
|
|
if (!list_empty(&pages_to_free)) {
|
|
pages_to_free.prev->next = NULL;
|
|
shmem_free_pages(pages_to_free.next);
|
|
}
|
|
}
|
|
|
|
static void shmem_truncate(struct inode *inode)
|
|
{
|
|
shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
|
|
}
|
|
|
|
static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct page *page = NULL;
|
|
int error;
|
|
|
|
if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
|
|
if (attr->ia_size < inode->i_size) {
|
|
/*
|
|
* If truncating down to a partial page, then
|
|
* if that page is already allocated, hold it
|
|
* in memory until the truncation is over, so
|
|
* truncate_partial_page cannnot miss it were
|
|
* it assigned to swap.
|
|
*/
|
|
if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
|
|
(void) shmem_getpage(inode,
|
|
attr->ia_size>>PAGE_CACHE_SHIFT,
|
|
&page, SGP_READ, NULL);
|
|
if (page)
|
|
unlock_page(page);
|
|
}
|
|
/*
|
|
* Reset SHMEM_PAGEIN flag so that shmem_truncate can
|
|
* detect if any pages might have been added to cache
|
|
* after truncate_inode_pages. But we needn't bother
|
|
* if it's being fully truncated to zero-length: the
|
|
* nrpages check is efficient enough in that case.
|
|
*/
|
|
if (attr->ia_size) {
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
spin_lock(&info->lock);
|
|
info->flags &= ~SHMEM_PAGEIN;
|
|
spin_unlock(&info->lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
error = inode_change_ok(inode, attr);
|
|
if (!error)
|
|
error = inode_setattr(inode, attr);
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
if (!error && (attr->ia_valid & ATTR_MODE))
|
|
error = generic_acl_chmod(inode, &shmem_acl_ops);
|
|
#endif
|
|
if (page)
|
|
page_cache_release(page);
|
|
return error;
|
|
}
|
|
|
|
static void shmem_delete_inode(struct inode *inode)
|
|
{
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
|
|
if (inode->i_op->truncate == shmem_truncate) {
|
|
truncate_inode_pages(inode->i_mapping, 0);
|
|
shmem_unacct_size(info->flags, inode->i_size);
|
|
inode->i_size = 0;
|
|
shmem_truncate(inode);
|
|
if (!list_empty(&info->swaplist)) {
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
list_del_init(&info->swaplist);
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
}
|
|
}
|
|
BUG_ON(inode->i_blocks);
|
|
shmem_free_inode(inode->i_sb);
|
|
clear_inode(inode);
|
|
}
|
|
|
|
static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
|
|
{
|
|
swp_entry_t *ptr;
|
|
|
|
for (ptr = dir; ptr < edir; ptr++) {
|
|
if (ptr->val == entry.val)
|
|
return ptr - dir;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
|
|
{
|
|
struct inode *inode;
|
|
unsigned long idx;
|
|
unsigned long size;
|
|
unsigned long limit;
|
|
unsigned long stage;
|
|
struct page **dir;
|
|
struct page *subdir;
|
|
swp_entry_t *ptr;
|
|
int offset;
|
|
int error;
|
|
|
|
idx = 0;
|
|
ptr = info->i_direct;
|
|
spin_lock(&info->lock);
|
|
if (!info->swapped) {
|
|
list_del_init(&info->swaplist);
|
|
goto lost2;
|
|
}
|
|
limit = info->next_index;
|
|
size = limit;
|
|
if (size > SHMEM_NR_DIRECT)
|
|
size = SHMEM_NR_DIRECT;
|
|
offset = shmem_find_swp(entry, ptr, ptr+size);
|
|
if (offset >= 0)
|
|
goto found;
|
|
if (!info->i_indirect)
|
|
goto lost2;
|
|
|
|
dir = shmem_dir_map(info->i_indirect);
|
|
stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
|
|
|
|
for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
|
|
if (unlikely(idx == stage)) {
|
|
shmem_dir_unmap(dir-1);
|
|
if (cond_resched_lock(&info->lock)) {
|
|
/* check it has not been truncated */
|
|
if (limit > info->next_index) {
|
|
limit = info->next_index;
|
|
if (idx >= limit)
|
|
goto lost2;
|
|
}
|
|
}
|
|
dir = shmem_dir_map(info->i_indirect) +
|
|
ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
|
|
while (!*dir) {
|
|
dir++;
|
|
idx += ENTRIES_PER_PAGEPAGE;
|
|
if (idx >= limit)
|
|
goto lost1;
|
|
}
|
|
stage = idx + ENTRIES_PER_PAGEPAGE;
|
|
subdir = *dir;
|
|
shmem_dir_unmap(dir);
|
|
dir = shmem_dir_map(subdir);
|
|
}
|
|
subdir = *dir;
|
|
if (subdir && page_private(subdir)) {
|
|
ptr = shmem_swp_map(subdir);
|
|
size = limit - idx;
|
|
if (size > ENTRIES_PER_PAGE)
|
|
size = ENTRIES_PER_PAGE;
|
|
offset = shmem_find_swp(entry, ptr, ptr+size);
|
|
shmem_swp_unmap(ptr);
|
|
if (offset >= 0) {
|
|
shmem_dir_unmap(dir);
|
|
goto found;
|
|
}
|
|
}
|
|
}
|
|
lost1:
|
|
shmem_dir_unmap(dir-1);
|
|
lost2:
|
|
spin_unlock(&info->lock);
|
|
return 0;
|
|
found:
|
|
idx += offset;
|
|
inode = igrab(&info->vfs_inode);
|
|
spin_unlock(&info->lock);
|
|
|
|
/*
|
|
* Move _head_ to start search for next from here.
|
|
* But be careful: shmem_delete_inode checks list_empty without taking
|
|
* mutex, and there's an instant in list_move_tail when info->swaplist
|
|
* would appear empty, if it were the only one on shmem_swaplist. We
|
|
* could avoid doing it if inode NULL; or use this minor optimization.
|
|
*/
|
|
if (shmem_swaplist.next != &info->swaplist)
|
|
list_move_tail(&shmem_swaplist, &info->swaplist);
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
|
|
error = 1;
|
|
if (!inode)
|
|
goto out;
|
|
/*
|
|
* Charge page using GFP_KERNEL while we can wait.
|
|
* Charged back to the user(not to caller) when swap account is used.
|
|
* add_to_page_cache() will be called with GFP_NOWAIT.
|
|
*/
|
|
error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
|
|
if (error)
|
|
goto out;
|
|
error = radix_tree_preload(GFP_KERNEL);
|
|
if (error) {
|
|
mem_cgroup_uncharge_cache_page(page);
|
|
goto out;
|
|
}
|
|
error = 1;
|
|
|
|
spin_lock(&info->lock);
|
|
ptr = shmem_swp_entry(info, idx, NULL);
|
|
if (ptr && ptr->val == entry.val) {
|
|
error = add_to_page_cache_locked(page, inode->i_mapping,
|
|
idx, GFP_NOWAIT);
|
|
/* does mem_cgroup_uncharge_cache_page on error */
|
|
} else /* we must compensate for our precharge above */
|
|
mem_cgroup_uncharge_cache_page(page);
|
|
|
|
if (error == -EEXIST) {
|
|
struct page *filepage = find_get_page(inode->i_mapping, idx);
|
|
error = 1;
|
|
if (filepage) {
|
|
/*
|
|
* There might be a more uptodate page coming down
|
|
* from a stacked writepage: forget our swappage if so.
|
|
*/
|
|
if (PageUptodate(filepage))
|
|
error = 0;
|
|
page_cache_release(filepage);
|
|
}
|
|
}
|
|
if (!error) {
|
|
delete_from_swap_cache(page);
|
|
set_page_dirty(page);
|
|
info->flags |= SHMEM_PAGEIN;
|
|
shmem_swp_set(info, ptr, 0);
|
|
swap_free(entry);
|
|
error = 1; /* not an error, but entry was found */
|
|
}
|
|
if (ptr)
|
|
shmem_swp_unmap(ptr);
|
|
spin_unlock(&info->lock);
|
|
radix_tree_preload_end();
|
|
out:
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
iput(inode); /* allows for NULL */
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* shmem_unuse() search for an eventually swapped out shmem page.
|
|
*/
|
|
int shmem_unuse(swp_entry_t entry, struct page *page)
|
|
{
|
|
struct list_head *p, *next;
|
|
struct shmem_inode_info *info;
|
|
int found = 0;
|
|
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
list_for_each_safe(p, next, &shmem_swaplist) {
|
|
info = list_entry(p, struct shmem_inode_info, swaplist);
|
|
found = shmem_unuse_inode(info, entry, page);
|
|
cond_resched();
|
|
if (found)
|
|
goto out;
|
|
}
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
/*
|
|
* Can some race bring us here? We've been holding page lock,
|
|
* so I think not; but would rather try again later than BUG()
|
|
*/
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
out:
|
|
return (found < 0) ? found : 0;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
swp_entry_t *entry, swap;
|
|
struct address_space *mapping;
|
|
unsigned long index;
|
|
struct inode *inode;
|
|
|
|
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;
|
|
|
|
/*
|
|
* shmem_backing_dev_info's capabilities prevent regular writeback or
|
|
* sync from ever calling shmem_writepage; but a stacking filesystem
|
|
* may use the ->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. However, in those cases,
|
|
* we do still want to check if there's a redundant swappage to be
|
|
* discarded.
|
|
*/
|
|
if (wbc->for_reclaim)
|
|
swap = get_swap_page();
|
|
else
|
|
swap.val = 0;
|
|
|
|
spin_lock(&info->lock);
|
|
if (index >= info->next_index) {
|
|
BUG_ON(!(info->flags & SHMEM_TRUNCATE));
|
|
goto unlock;
|
|
}
|
|
entry = shmem_swp_entry(info, index, NULL);
|
|
if (entry->val) {
|
|
/*
|
|
* The more uptodate page coming down from a stacked
|
|
* writepage should replace our old swappage.
|
|
*/
|
|
free_swap_and_cache(*entry);
|
|
shmem_swp_set(info, entry, 0);
|
|
}
|
|
shmem_recalc_inode(inode);
|
|
|
|
if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
|
|
remove_from_page_cache(page);
|
|
shmem_swp_set(info, entry, swap.val);
|
|
shmem_swp_unmap(entry);
|
|
if (list_empty(&info->swaplist))
|
|
inode = igrab(inode);
|
|
else
|
|
inode = NULL;
|
|
spin_unlock(&info->lock);
|
|
swap_shmem_alloc(swap);
|
|
BUG_ON(page_mapped(page));
|
|
page_cache_release(page); /* pagecache ref */
|
|
swap_writepage(page, wbc);
|
|
if (inode) {
|
|
mutex_lock(&shmem_swaplist_mutex);
|
|
/* move instead of add in case we're racing */
|
|
list_move_tail(&info->swaplist, &shmem_swaplist);
|
|
mutex_unlock(&shmem_swaplist_mutex);
|
|
iput(inode);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
shmem_swp_unmap(entry);
|
|
unlock:
|
|
spin_unlock(&info->lock);
|
|
/*
|
|
* add_to_swap_cache() doesn't return -EEXIST, so we can safely
|
|
* clear SWAP_HAS_CACHE flag.
|
|
*/
|
|
swapcache_free(swap, NULL);
|
|
redirty:
|
|
set_page_dirty(page);
|
|
if (wbc->for_reclaim)
|
|
return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
#ifdef 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, 1);
|
|
|
|
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;
|
|
}
|
|
#endif /* CONFIG_TMPFS */
|
|
|
|
static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
|
|
struct shmem_inode_info *info, unsigned long idx)
|
|
{
|
|
struct mempolicy mpol, *spol;
|
|
struct vm_area_struct pvma;
|
|
struct page *page;
|
|
|
|
spol = mpol_cond_copy(&mpol,
|
|
mpol_shared_policy_lookup(&info->policy, idx));
|
|
|
|
/* Create a pseudo vma that just contains the policy */
|
|
pvma.vm_start = 0;
|
|
pvma.vm_pgoff = idx;
|
|
pvma.vm_ops = NULL;
|
|
pvma.vm_policy = spol;
|
|
page = swapin_readahead(entry, gfp, &pvma, 0);
|
|
return page;
|
|
}
|
|
|
|
static struct page *shmem_alloc_page(gfp_t gfp,
|
|
struct shmem_inode_info *info, unsigned long idx)
|
|
{
|
|
struct vm_area_struct pvma;
|
|
|
|
/* Create a pseudo vma that just contains the policy */
|
|
pvma.vm_start = 0;
|
|
pvma.vm_pgoff = idx;
|
|
pvma.vm_ops = NULL;
|
|
pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
|
|
|
|
/*
|
|
* alloc_page_vma() will drop the shared policy reference
|
|
*/
|
|
return alloc_page_vma(gfp, &pvma, 0);
|
|
}
|
|
#else /* !CONFIG_NUMA */
|
|
#ifdef CONFIG_TMPFS
|
|
static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
|
|
{
|
|
}
|
|
#endif /* CONFIG_TMPFS */
|
|
|
|
static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
|
|
struct shmem_inode_info *info, unsigned long idx)
|
|
{
|
|
return swapin_readahead(entry, gfp, NULL, 0);
|
|
}
|
|
|
|
static inline struct page *shmem_alloc_page(gfp_t gfp,
|
|
struct shmem_inode_info *info, unsigned long idx)
|
|
{
|
|
return alloc_page(gfp);
|
|
}
|
|
#endif /* CONFIG_NUMA */
|
|
|
|
#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
|
|
static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* shmem_getpage - either get the page from swap or allocate a new one
|
|
*
|
|
* 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
|
|
*/
|
|
static int shmem_getpage(struct inode *inode, unsigned long idx,
|
|
struct page **pagep, enum sgp_type sgp, int *type)
|
|
{
|
|
struct address_space *mapping = inode->i_mapping;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
struct shmem_sb_info *sbinfo;
|
|
struct page *filepage = *pagep;
|
|
struct page *swappage;
|
|
swp_entry_t *entry;
|
|
swp_entry_t swap;
|
|
gfp_t gfp;
|
|
int error;
|
|
|
|
if (idx >= SHMEM_MAX_INDEX)
|
|
return -EFBIG;
|
|
|
|
if (type)
|
|
*type = 0;
|
|
|
|
/*
|
|
* Normally, filepage is NULL on entry, and either found
|
|
* uptodate immediately, or allocated and zeroed, or read
|
|
* in under swappage, which is then assigned to filepage.
|
|
* But shmem_readpage (required for splice) passes in a locked
|
|
* filepage, which may be found not uptodate by other callers
|
|
* too, and may need to be copied from the swappage read in.
|
|
*/
|
|
repeat:
|
|
if (!filepage)
|
|
filepage = find_lock_page(mapping, idx);
|
|
if (filepage && PageUptodate(filepage))
|
|
goto done;
|
|
error = 0;
|
|
gfp = mapping_gfp_mask(mapping);
|
|
if (!filepage) {
|
|
/*
|
|
* Try to preload while we can wait, to not make a habit of
|
|
* draining atomic reserves; but don't latch on to this cpu.
|
|
*/
|
|
error = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
|
|
if (error)
|
|
goto failed;
|
|
radix_tree_preload_end();
|
|
}
|
|
|
|
spin_lock(&info->lock);
|
|
shmem_recalc_inode(inode);
|
|
entry = shmem_swp_alloc(info, idx, sgp);
|
|
if (IS_ERR(entry)) {
|
|
spin_unlock(&info->lock);
|
|
error = PTR_ERR(entry);
|
|
goto failed;
|
|
}
|
|
swap = *entry;
|
|
|
|
if (swap.val) {
|
|
/* Look it up and read it in.. */
|
|
swappage = lookup_swap_cache(swap);
|
|
if (!swappage) {
|
|
shmem_swp_unmap(entry);
|
|
/* here we actually do the io */
|
|
if (type && !(*type & VM_FAULT_MAJOR)) {
|
|
__count_vm_event(PGMAJFAULT);
|
|
*type |= VM_FAULT_MAJOR;
|
|
}
|
|
spin_unlock(&info->lock);
|
|
swappage = shmem_swapin(swap, gfp, info, idx);
|
|
if (!swappage) {
|
|
spin_lock(&info->lock);
|
|
entry = shmem_swp_alloc(info, idx, sgp);
|
|
if (IS_ERR(entry))
|
|
error = PTR_ERR(entry);
|
|
else {
|
|
if (entry->val == swap.val)
|
|
error = -ENOMEM;
|
|
shmem_swp_unmap(entry);
|
|
}
|
|
spin_unlock(&info->lock);
|
|
if (error)
|
|
goto failed;
|
|
goto repeat;
|
|
}
|
|
wait_on_page_locked(swappage);
|
|
page_cache_release(swappage);
|
|
goto repeat;
|
|
}
|
|
|
|
/* We have to do this with page locked to prevent races */
|
|
if (!trylock_page(swappage)) {
|
|
shmem_swp_unmap(entry);
|
|
spin_unlock(&info->lock);
|
|
wait_on_page_locked(swappage);
|
|
page_cache_release(swappage);
|
|
goto repeat;
|
|
}
|
|
if (PageWriteback(swappage)) {
|
|
shmem_swp_unmap(entry);
|
|
spin_unlock(&info->lock);
|
|
wait_on_page_writeback(swappage);
|
|
unlock_page(swappage);
|
|
page_cache_release(swappage);
|
|
goto repeat;
|
|
}
|
|
if (!PageUptodate(swappage)) {
|
|
shmem_swp_unmap(entry);
|
|
spin_unlock(&info->lock);
|
|
unlock_page(swappage);
|
|
page_cache_release(swappage);
|
|
error = -EIO;
|
|
goto failed;
|
|
}
|
|
|
|
if (filepage) {
|
|
shmem_swp_set(info, entry, 0);
|
|
shmem_swp_unmap(entry);
|
|
delete_from_swap_cache(swappage);
|
|
spin_unlock(&info->lock);
|
|
copy_highpage(filepage, swappage);
|
|
unlock_page(swappage);
|
|
page_cache_release(swappage);
|
|
flush_dcache_page(filepage);
|
|
SetPageUptodate(filepage);
|
|
set_page_dirty(filepage);
|
|
swap_free(swap);
|
|
} else if (!(error = add_to_page_cache_locked(swappage, mapping,
|
|
idx, GFP_NOWAIT))) {
|
|
info->flags |= SHMEM_PAGEIN;
|
|
shmem_swp_set(info, entry, 0);
|
|
shmem_swp_unmap(entry);
|
|
delete_from_swap_cache(swappage);
|
|
spin_unlock(&info->lock);
|
|
filepage = swappage;
|
|
set_page_dirty(filepage);
|
|
swap_free(swap);
|
|
} else {
|
|
shmem_swp_unmap(entry);
|
|
spin_unlock(&info->lock);
|
|
if (error == -ENOMEM) {
|
|
/*
|
|
* reclaim from proper memory cgroup and
|
|
* call memcg's OOM if needed.
|
|
*/
|
|
error = mem_cgroup_shmem_charge_fallback(
|
|
swappage,
|
|
current->mm,
|
|
gfp);
|
|
if (error) {
|
|
unlock_page(swappage);
|
|
page_cache_release(swappage);
|
|
goto failed;
|
|
}
|
|
}
|
|
unlock_page(swappage);
|
|
page_cache_release(swappage);
|
|
goto repeat;
|
|
}
|
|
} else if (sgp == SGP_READ && !filepage) {
|
|
shmem_swp_unmap(entry);
|
|
filepage = find_get_page(mapping, idx);
|
|
if (filepage &&
|
|
(!PageUptodate(filepage) || !trylock_page(filepage))) {
|
|
spin_unlock(&info->lock);
|
|
wait_on_page_locked(filepage);
|
|
page_cache_release(filepage);
|
|
filepage = NULL;
|
|
goto repeat;
|
|
}
|
|
spin_unlock(&info->lock);
|
|
} else {
|
|
shmem_swp_unmap(entry);
|
|
sbinfo = SHMEM_SB(inode->i_sb);
|
|
if (sbinfo->max_blocks) {
|
|
spin_lock(&sbinfo->stat_lock);
|
|
if (sbinfo->free_blocks == 0 ||
|
|
shmem_acct_block(info->flags)) {
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
spin_unlock(&info->lock);
|
|
error = -ENOSPC;
|
|
goto failed;
|
|
}
|
|
sbinfo->free_blocks--;
|
|
inode->i_blocks += BLOCKS_PER_PAGE;
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
} else if (shmem_acct_block(info->flags)) {
|
|
spin_unlock(&info->lock);
|
|
error = -ENOSPC;
|
|
goto failed;
|
|
}
|
|
|
|
if (!filepage) {
|
|
int ret;
|
|
|
|
spin_unlock(&info->lock);
|
|
filepage = shmem_alloc_page(gfp, info, idx);
|
|
if (!filepage) {
|
|
shmem_unacct_blocks(info->flags, 1);
|
|
shmem_free_blocks(inode, 1);
|
|
error = -ENOMEM;
|
|
goto failed;
|
|
}
|
|
SetPageSwapBacked(filepage);
|
|
|
|
/* Precharge page while we can wait, compensate after */
|
|
error = mem_cgroup_cache_charge(filepage, current->mm,
|
|
GFP_KERNEL);
|
|
if (error) {
|
|
page_cache_release(filepage);
|
|
shmem_unacct_blocks(info->flags, 1);
|
|
shmem_free_blocks(inode, 1);
|
|
filepage = NULL;
|
|
goto failed;
|
|
}
|
|
|
|
spin_lock(&info->lock);
|
|
entry = shmem_swp_alloc(info, idx, sgp);
|
|
if (IS_ERR(entry))
|
|
error = PTR_ERR(entry);
|
|
else {
|
|
swap = *entry;
|
|
shmem_swp_unmap(entry);
|
|
}
|
|
ret = error || swap.val;
|
|
if (ret)
|
|
mem_cgroup_uncharge_cache_page(filepage);
|
|
else
|
|
ret = add_to_page_cache_lru(filepage, mapping,
|
|
idx, GFP_NOWAIT);
|
|
/*
|
|
* At add_to_page_cache_lru() failure, uncharge will
|
|
* be done automatically.
|
|
*/
|
|
if (ret) {
|
|
spin_unlock(&info->lock);
|
|
page_cache_release(filepage);
|
|
shmem_unacct_blocks(info->flags, 1);
|
|
shmem_free_blocks(inode, 1);
|
|
filepage = NULL;
|
|
if (error)
|
|
goto failed;
|
|
goto repeat;
|
|
}
|
|
info->flags |= SHMEM_PAGEIN;
|
|
}
|
|
|
|
info->alloced++;
|
|
spin_unlock(&info->lock);
|
|
clear_highpage(filepage);
|
|
flush_dcache_page(filepage);
|
|
SetPageUptodate(filepage);
|
|
if (sgp == SGP_DIRTY)
|
|
set_page_dirty(filepage);
|
|
}
|
|
done:
|
|
*pagep = filepage;
|
|
return 0;
|
|
|
|
failed:
|
|
if (*pagep != filepage) {
|
|
unlock_page(filepage);
|
|
page_cache_release(filepage);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
|
|
int error;
|
|
int ret;
|
|
|
|
if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
|
|
if (error)
|
|
return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
|
|
|
|
return ret | VM_FAULT_LOCKED;
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
|
|
{
|
|
struct inode *i = vma->vm_file->f_path.dentry->d_inode;
|
|
return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
|
|
}
|
|
|
|
static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
|
|
unsigned long addr)
|
|
{
|
|
struct inode *i = vma->vm_file->f_path.dentry->d_inode;
|
|
unsigned long idx;
|
|
|
|
idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
|
|
return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
|
|
}
|
|
#endif
|
|
|
|
int shmem_lock(struct file *file, int lock, struct user_struct *user)
|
|
{
|
|
struct inode *inode = file->f_path.dentry->d_inode;
|
|
struct shmem_inode_info *info = SHMEM_I(inode);
|
|
int retval = -ENOMEM;
|
|
|
|
spin_lock(&info->lock);
|
|
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);
|
|
scan_mapping_unevictable_pages(file->f_mapping);
|
|
}
|
|
retval = 0;
|
|
|
|
out_nomem:
|
|
spin_unlock(&info->lock);
|
|
return retval;
|
|
}
|
|
|
|
static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
file_accessed(file);
|
|
vma->vm_ops = &shmem_vm_ops;
|
|
vma->vm_flags |= VM_CAN_NONLINEAR;
|
|
return 0;
|
|
}
|
|
|
|
static struct inode *shmem_get_inode(struct super_block *sb, int mode,
|
|
dev_t dev, unsigned long flags)
|
|
{
|
|
struct inode *inode;
|
|
struct shmem_inode_info *info;
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
|
|
if (shmem_reserve_inode(sb))
|
|
return NULL;
|
|
|
|
inode = new_inode(sb);
|
|
if (inode) {
|
|
inode->i_mode = mode;
|
|
inode->i_uid = current_fsuid();
|
|
inode->i_gid = current_fsgid();
|
|
inode->i_blocks = 0;
|
|
inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
|
|
inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
|
|
inode->i_generation = get_seconds();
|
|
info = SHMEM_I(inode);
|
|
memset(info, 0, (char *)inode - (char *)info);
|
|
spin_lock_init(&info->lock);
|
|
info->flags = flags & VM_NORESERVE;
|
|
INIT_LIST_HEAD(&info->swaplist);
|
|
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;
|
|
}
|
|
} else
|
|
shmem_free_inode(sb);
|
|
return inode;
|
|
}
|
|
|
|
#ifdef CONFIG_TMPFS
|
|
static const struct inode_operations shmem_symlink_inode_operations;
|
|
static const struct inode_operations shmem_symlink_inline_operations;
|
|
|
|
/*
|
|
* Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin;
|
|
* but providing them allows a tmpfs file to be used for splice, sendfile, and
|
|
* below the loop driver, in the generic fashion that many filesystems support.
|
|
*/
|
|
static int shmem_readpage(struct file *file, struct page *page)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
|
|
unlock_page(page);
|
|
return error;
|
|
}
|
|
|
|
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;
|
|
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
|
|
*pagep = NULL;
|
|
return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
|
|
}
|
|
|
|
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);
|
|
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
|
|
return copied;
|
|
}
|
|
|
|
static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
|
|
{
|
|
struct inode *inode = filp->f_path.dentry->d_inode;
|
|
struct address_space *mapping = inode->i_mapping;
|
|
unsigned long index, offset;
|
|
enum sgp_type sgp = SGP_READ;
|
|
|
|
/*
|
|
* 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 (segment_eq(get_fs(), KERNEL_DS))
|
|
sgp = SGP_DIRTY;
|
|
|
|
index = *ppos >> PAGE_CACHE_SHIFT;
|
|
offset = *ppos & ~PAGE_CACHE_MASK;
|
|
|
|
for (;;) {
|
|
struct page *page = NULL;
|
|
unsigned long end_index, nr, ret;
|
|
loff_t i_size = i_size_read(inode);
|
|
|
|
end_index = i_size >> PAGE_CACHE_SHIFT;
|
|
if (index > end_index)
|
|
break;
|
|
if (index == end_index) {
|
|
nr = i_size & ~PAGE_CACHE_MASK;
|
|
if (nr <= offset)
|
|
break;
|
|
}
|
|
|
|
desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
|
|
if (desc->error) {
|
|
if (desc->error == -EINVAL)
|
|
desc->error = 0;
|
|
break;
|
|
}
|
|
if (page)
|
|
unlock_page(page);
|
|
|
|
/*
|
|
* We must evaluate after, since reads (unlike writes)
|
|
* are called without i_mutex protection against truncate
|
|
*/
|
|
nr = PAGE_CACHE_SIZE;
|
|
i_size = i_size_read(inode);
|
|
end_index = i_size >> PAGE_CACHE_SHIFT;
|
|
if (index == end_index) {
|
|
nr = i_size & ~PAGE_CACHE_MASK;
|
|
if (nr <= offset) {
|
|
if (page)
|
|
page_cache_release(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);
|
|
page_cache_get(page);
|
|
}
|
|
|
|
/*
|
|
* Ok, we have the page, and it's up-to-date, so
|
|
* now we can copy it to user space...
|
|
*
|
|
* The actor routine returns how many bytes were actually used..
|
|
* NOTE! This may not be the same as how much of a user buffer
|
|
* we filled up (we may be padding etc), so we can only update
|
|
* "pos" here (the actor routine has to update the user buffer
|
|
* pointers and the remaining count).
|
|
*/
|
|
ret = actor(desc, page, offset, nr);
|
|
offset += ret;
|
|
index += offset >> PAGE_CACHE_SHIFT;
|
|
offset &= ~PAGE_CACHE_MASK;
|
|
|
|
page_cache_release(page);
|
|
if (ret != nr || !desc->count)
|
|
break;
|
|
|
|
cond_resched();
|
|
}
|
|
|
|
*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
|
|
file_accessed(filp);
|
|
}
|
|
|
|
static ssize_t shmem_file_aio_read(struct kiocb *iocb,
|
|
const struct iovec *iov, unsigned long nr_segs, loff_t pos)
|
|
{
|
|
struct file *filp = iocb->ki_filp;
|
|
ssize_t retval;
|
|
unsigned long seg;
|
|
size_t count;
|
|
loff_t *ppos = &iocb->ki_pos;
|
|
|
|
retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
|
|
if (retval)
|
|
return retval;
|
|
|
|
for (seg = 0; seg < nr_segs; seg++) {
|
|
read_descriptor_t desc;
|
|
|
|
desc.written = 0;
|
|
desc.arg.buf = iov[seg].iov_base;
|
|
desc.count = iov[seg].iov_len;
|
|
if (desc.count == 0)
|
|
continue;
|
|
desc.error = 0;
|
|
do_shmem_file_read(filp, ppos, &desc, file_read_actor);
|
|
retval += desc.written;
|
|
if (desc.error) {
|
|
retval = retval ?: desc.error;
|
|
break;
|
|
}
|
|
if (desc.count > 0)
|
|
break;
|
|
}
|
|
return retval;
|
|
}
|
|
|
|
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_CACHE_SIZE;
|
|
buf->f_namelen = NAME_MAX;
|
|
spin_lock(&sbinfo->stat_lock);
|
|
if (sbinfo->max_blocks) {
|
|
buf->f_blocks = sbinfo->max_blocks;
|
|
buf->f_bavail = buf->f_bfree = sbinfo->free_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 */
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* File creation. Allocate an inode, and we're done..
|
|
*/
|
|
static int
|
|
shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
|
|
{
|
|
struct inode *inode;
|
|
int error = -ENOSPC;
|
|
|
|
inode = shmem_get_inode(dir->i_sb, mode, dev, VM_NORESERVE);
|
|
if (inode) {
|
|
error = security_inode_init_security(inode, dir, NULL, NULL,
|
|
NULL);
|
|
if (error) {
|
|
if (error != -EOPNOTSUPP) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
}
|
|
error = shmem_acl_init(inode, dir);
|
|
if (error) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
if (dir->i_mode & S_ISGID) {
|
|
inode->i_gid = dir->i_gid;
|
|
if (S_ISDIR(mode))
|
|
inode->i_mode |= S_ISGID;
|
|
}
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry); /* Extra count - pin the dentry in core */
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
|
|
{
|
|
int error;
|
|
|
|
if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
|
|
return error;
|
|
inc_nlink(dir);
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
|
|
struct nameidata *nd)
|
|
{
|
|
return shmem_mknod(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 = old_dentry->d_inode;
|
|
int ret;
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
ret = shmem_reserve_inode(inode->i_sb);
|
|
if (ret)
|
|
goto out;
|
|
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
inc_nlink(inode);
|
|
atomic_inc(&inode->i_count); /* 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 = dentry->d_inode;
|
|
|
|
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;
|
|
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(dentry->d_inode);
|
|
drop_nlink(dir);
|
|
return shmem_unlink(dir, dentry);
|
|
}
|
|
|
|
/*
|
|
* 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_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
|
|
{
|
|
struct inode *inode = old_dentry->d_inode;
|
|
int they_are_dirs = S_ISDIR(inode->i_mode);
|
|
|
|
if (!simple_empty(new_dentry))
|
|
return -ENOTEMPTY;
|
|
|
|
if (new_dentry->d_inode) {
|
|
(void) shmem_unlink(new_dir, new_dentry);
|
|
if (they_are_dirs)
|
|
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;
|
|
return 0;
|
|
}
|
|
|
|
static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
|
|
{
|
|
int error;
|
|
int len;
|
|
struct inode *inode;
|
|
struct page *page = NULL;
|
|
char *kaddr;
|
|
struct shmem_inode_info *info;
|
|
|
|
len = strlen(symname) + 1;
|
|
if (len > PAGE_CACHE_SIZE)
|
|
return -ENAMETOOLONG;
|
|
|
|
inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE);
|
|
if (!inode)
|
|
return -ENOSPC;
|
|
|
|
error = security_inode_init_security(inode, dir, NULL, NULL,
|
|
NULL);
|
|
if (error) {
|
|
if (error != -EOPNOTSUPP) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
error = 0;
|
|
}
|
|
|
|
info = SHMEM_I(inode);
|
|
inode->i_size = len-1;
|
|
if (len <= (char *)inode - (char *)info) {
|
|
/* do it inline */
|
|
memcpy(info, symname, len);
|
|
inode->i_op = &shmem_symlink_inline_operations;
|
|
} else {
|
|
error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
|
|
if (error) {
|
|
iput(inode);
|
|
return error;
|
|
}
|
|
inode->i_mapping->a_ops = &shmem_aops;
|
|
inode->i_op = &shmem_symlink_inode_operations;
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memcpy(kaddr, symname, len);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
set_page_dirty(page);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
}
|
|
if (dir->i_mode & S_ISGID)
|
|
inode->i_gid = dir->i_gid;
|
|
dir->i_size += BOGO_DIRENT_SIZE;
|
|
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
|
|
d_instantiate(dentry, inode);
|
|
dget(dentry);
|
|
return 0;
|
|
}
|
|
|
|
static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
|
|
return NULL;
|
|
}
|
|
|
|
static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
struct page *page = NULL;
|
|
int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
|
|
nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
|
|
if (page)
|
|
unlock_page(page);
|
|
return page;
|
|
}
|
|
|
|
static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
|
|
{
|
|
if (!IS_ERR(nd_get_link(nd))) {
|
|
struct page *page = cookie;
|
|
kunmap(page);
|
|
mark_page_accessed(page);
|
|
page_cache_release(page);
|
|
}
|
|
}
|
|
|
|
static const struct inode_operations shmem_symlink_inline_operations = {
|
|
.readlink = generic_readlink,
|
|
.follow_link = shmem_follow_link_inline,
|
|
};
|
|
|
|
static const struct inode_operations shmem_symlink_inode_operations = {
|
|
.truncate = shmem_truncate,
|
|
.readlink = generic_readlink,
|
|
.follow_link = shmem_follow_link,
|
|
.put_link = shmem_put_link,
|
|
};
|
|
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
/*
|
|
* Superblocks without xattr inode operations will get security.* xattr
|
|
* support from the VFS "for free". As soon as we have any other xattrs
|
|
* like ACLs, we also need to implement the security.* handlers at
|
|
* filesystem level, though.
|
|
*/
|
|
|
|
static size_t shmem_xattr_security_list(struct inode *inode, char *list,
|
|
size_t list_len, const char *name,
|
|
size_t name_len)
|
|
{
|
|
return security_inode_listsecurity(inode, list, list_len);
|
|
}
|
|
|
|
static int shmem_xattr_security_get(struct inode *inode, const char *name,
|
|
void *buffer, size_t size)
|
|
{
|
|
if (strcmp(name, "") == 0)
|
|
return -EINVAL;
|
|
return xattr_getsecurity(inode, name, buffer, size);
|
|
}
|
|
|
|
static int shmem_xattr_security_set(struct inode *inode, const char *name,
|
|
const void *value, size_t size, int flags)
|
|
{
|
|
if (strcmp(name, "") == 0)
|
|
return -EINVAL;
|
|
return security_inode_setsecurity(inode, name, value, size, flags);
|
|
}
|
|
|
|
static struct xattr_handler shmem_xattr_security_handler = {
|
|
.prefix = XATTR_SECURITY_PREFIX,
|
|
.list = shmem_xattr_security_list,
|
|
.get = shmem_xattr_security_get,
|
|
.set = shmem_xattr_security_set,
|
|
};
|
|
|
|
static struct xattr_handler *shmem_xattr_handlers[] = {
|
|
&shmem_xattr_acl_access_handler,
|
|
&shmem_xattr_acl_default_handler,
|
|
&shmem_xattr_security_handler,
|
|
NULL
|
|
};
|
|
#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;
|
|
}
|
|
|
|
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 = fid->raw[2];
|
|
inum = (inum << 32) | fid->raw[1];
|
|
|
|
if (fh_len < 3)
|
|
return NULL;
|
|
|
|
inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
|
|
shmem_match, fid->raw);
|
|
if (inode) {
|
|
dentry = d_find_alias(inode);
|
|
iput(inode);
|
|
}
|
|
|
|
return dentry;
|
|
}
|
|
|
|
static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
|
|
int connectable)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
|
|
if (*len < 3)
|
|
return 255;
|
|
|
|
if (hlist_unhashed(&inode->i_hash)) {
|
|
/* 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 (hlist_unhashed(&inode->i_hash))
|
|
__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,
|
|
};
|
|
|
|
static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
|
|
bool remount)
|
|
{
|
|
char *this_char, *value, *rest;
|
|
|
|
while (options != NULL) {
|
|
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)
|
|
continue;
|
|
if ((value = strchr(this_char,'=')) != NULL) {
|
|
*value++ = 0;
|
|
} else {
|
|
printk(KERN_ERR
|
|
"tmpfs: No value for mount option '%s'\n",
|
|
this_char);
|
|
return 1;
|
|
}
|
|
|
|
if (!strcmp(this_char,"size")) {
|
|
unsigned long long size;
|
|
size = memparse(value,&rest);
|
|
if (*rest == '%') {
|
|
size <<= PAGE_SHIFT;
|
|
size *= totalram_pages;
|
|
do_div(size, 100);
|
|
rest++;
|
|
}
|
|
if (*rest)
|
|
goto bad_val;
|
|
sbinfo->max_blocks =
|
|
DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
|
|
} else if (!strcmp(this_char,"nr_blocks")) {
|
|
sbinfo->max_blocks = memparse(value, &rest);
|
|
if (*rest)
|
|
goto bad_val;
|
|
} else if (!strcmp(this_char,"nr_inodes")) {
|
|
sbinfo->max_inodes = memparse(value, &rest);
|
|
if (*rest)
|
|
goto bad_val;
|
|
} else if (!strcmp(this_char,"mode")) {
|
|
if (remount)
|
|
continue;
|
|
sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
|
|
if (*rest)
|
|
goto bad_val;
|
|
} else if (!strcmp(this_char,"uid")) {
|
|
if (remount)
|
|
continue;
|
|
sbinfo->uid = simple_strtoul(value, &rest, 0);
|
|
if (*rest)
|
|
goto bad_val;
|
|
} else if (!strcmp(this_char,"gid")) {
|
|
if (remount)
|
|
continue;
|
|
sbinfo->gid = simple_strtoul(value, &rest, 0);
|
|
if (*rest)
|
|
goto bad_val;
|
|
} else if (!strcmp(this_char,"mpol")) {
|
|
if (mpol_parse_str(value, &sbinfo->mpol, 1))
|
|
goto bad_val;
|
|
} else {
|
|
printk(KERN_ERR "tmpfs: Bad mount option %s\n",
|
|
this_char);
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
bad_val:
|
|
printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
|
|
value, this_char);
|
|
return 1;
|
|
|
|
}
|
|
|
|
static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
|
|
struct shmem_sb_info config = *sbinfo;
|
|
unsigned long blocks;
|
|
unsigned long inodes;
|
|
int error = -EINVAL;
|
|
|
|
if (shmem_parse_options(data, &config, true))
|
|
return error;
|
|
|
|
spin_lock(&sbinfo->stat_lock);
|
|
blocks = sbinfo->max_blocks - sbinfo->free_blocks;
|
|
inodes = sbinfo->max_inodes - sbinfo->free_inodes;
|
|
if (config.max_blocks < blocks)
|
|
goto out;
|
|
if (config.max_inodes < inodes)
|
|
goto out;
|
|
/*
|
|
* Those tests also disallow limited->unlimited while any are in
|
|
* use, so i_blocks will always be zero when max_blocks is zero;
|
|
* but we must separately disallow unlimited->limited, because
|
|
* in that case we have no record of how much is already in use.
|
|
*/
|
|
if (config.max_blocks && !sbinfo->max_blocks)
|
|
goto out;
|
|
if (config.max_inodes && !sbinfo->max_inodes)
|
|
goto out;
|
|
|
|
error = 0;
|
|
sbinfo->max_blocks = config.max_blocks;
|
|
sbinfo->free_blocks = config.max_blocks - blocks;
|
|
sbinfo->max_inodes = config.max_inodes;
|
|
sbinfo->free_inodes = config.max_inodes - inodes;
|
|
|
|
mpol_put(sbinfo->mpol);
|
|
sbinfo->mpol = config.mpol; /* transfers initial ref */
|
|
out:
|
|
spin_unlock(&sbinfo->stat_lock);
|
|
return error;
|
|
}
|
|
|
|
static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
|
|
{
|
|
struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb);
|
|
|
|
if (sbinfo->max_blocks != shmem_default_max_blocks())
|
|
seq_printf(seq, ",size=%luk",
|
|
sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
|
|
if (sbinfo->max_inodes != shmem_default_max_inodes())
|
|
seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
|
|
if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
|
|
seq_printf(seq, ",mode=%03o", sbinfo->mode);
|
|
if (sbinfo->uid != 0)
|
|
seq_printf(seq, ",uid=%u", sbinfo->uid);
|
|
if (sbinfo->gid != 0)
|
|
seq_printf(seq, ",gid=%u", sbinfo->gid);
|
|
shmem_show_mpol(seq, sbinfo->mpol);
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_TMPFS */
|
|
|
|
static void shmem_put_super(struct super_block *sb)
|
|
{
|
|
kfree(sb->s_fs_info);
|
|
sb->s_fs_info = NULL;
|
|
}
|
|
|
|
int shmem_fill_super(struct super_block *sb, void *data, int silent)
|
|
{
|
|
struct inode *inode;
|
|
struct dentry *root;
|
|
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;
|
|
|
|
sbinfo->mode = S_IRWXUGO | S_ISVTX;
|
|
sbinfo->uid = current_fsuid();
|
|
sbinfo->gid = current_fsgid();
|
|
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 & MS_NOUSER)) {
|
|
sbinfo->max_blocks = shmem_default_max_blocks();
|
|
sbinfo->max_inodes = shmem_default_max_inodes();
|
|
if (shmem_parse_options(data, sbinfo, false)) {
|
|
err = -EINVAL;
|
|
goto failed;
|
|
}
|
|
}
|
|
sb->s_export_op = &shmem_export_ops;
|
|
#else
|
|
sb->s_flags |= MS_NOUSER;
|
|
#endif
|
|
|
|
spin_lock_init(&sbinfo->stat_lock);
|
|
sbinfo->free_blocks = sbinfo->max_blocks;
|
|
sbinfo->free_inodes = sbinfo->max_inodes;
|
|
|
|
sb->s_maxbytes = SHMEM_MAX_BYTES;
|
|
sb->s_blocksize = PAGE_CACHE_SIZE;
|
|
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
|
sb->s_magic = TMPFS_MAGIC;
|
|
sb->s_op = &shmem_ops;
|
|
sb->s_time_gran = 1;
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
sb->s_xattr = shmem_xattr_handlers;
|
|
sb->s_flags |= MS_POSIXACL;
|
|
#endif
|
|
|
|
inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE);
|
|
if (!inode)
|
|
goto failed;
|
|
inode->i_uid = sbinfo->uid;
|
|
inode->i_gid = sbinfo->gid;
|
|
root = d_alloc_root(inode);
|
|
if (!root)
|
|
goto failed_iput;
|
|
sb->s_root = root;
|
|
return 0;
|
|
|
|
failed_iput:
|
|
iput(inode);
|
|
failed:
|
|
shmem_put_super(sb);
|
|
return err;
|
|
}
|
|
|
|
static struct kmem_cache *shmem_inode_cachep;
|
|
|
|
static struct inode *shmem_alloc_inode(struct super_block *sb)
|
|
{
|
|
struct shmem_inode_info *p;
|
|
p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
|
|
if (!p)
|
|
return NULL;
|
|
return &p->vfs_inode;
|
|
}
|
|
|
|
static void shmem_destroy_inode(struct inode *inode)
|
|
{
|
|
if ((inode->i_mode & S_IFMT) == S_IFREG) {
|
|
/* only struct inode is valid if it's an inline symlink */
|
|
mpol_free_shared_policy(&SHMEM_I(inode)->policy);
|
|
}
|
|
kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
|
|
}
|
|
|
|
static void init_once(void *foo)
|
|
{
|
|
struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
|
|
|
|
inode_init_once(&p->vfs_inode);
|
|
}
|
|
|
|
static int init_inodecache(void)
|
|
{
|
|
shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
|
|
sizeof(struct shmem_inode_info),
|
|
0, SLAB_PANIC, init_once);
|
|
return 0;
|
|
}
|
|
|
|
static void destroy_inodecache(void)
|
|
{
|
|
kmem_cache_destroy(shmem_inode_cachep);
|
|
}
|
|
|
|
static const struct address_space_operations shmem_aops = {
|
|
.writepage = shmem_writepage,
|
|
.set_page_dirty = __set_page_dirty_no_writeback,
|
|
#ifdef CONFIG_TMPFS
|
|
.readpage = shmem_readpage,
|
|
.write_begin = shmem_write_begin,
|
|
.write_end = shmem_write_end,
|
|
#endif
|
|
.migratepage = migrate_page,
|
|
.error_remove_page = generic_error_remove_page,
|
|
};
|
|
|
|
static const struct file_operations shmem_file_operations = {
|
|
.mmap = shmem_mmap,
|
|
#ifdef CONFIG_TMPFS
|
|
.llseek = generic_file_llseek,
|
|
.read = do_sync_read,
|
|
.write = do_sync_write,
|
|
.aio_read = shmem_file_aio_read,
|
|
.aio_write = generic_file_aio_write,
|
|
.fsync = simple_sync_file,
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = generic_file_splice_write,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_inode_operations = {
|
|
.truncate = shmem_truncate,
|
|
.setattr = shmem_notify_change,
|
|
.truncate_range = shmem_truncate_range,
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
.setxattr = generic_setxattr,
|
|
.getxattr = generic_getxattr,
|
|
.listxattr = generic_listxattr,
|
|
.removexattr = generic_removexattr,
|
|
.check_acl = shmem_check_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_rename,
|
|
#endif
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
.setattr = shmem_notify_change,
|
|
.setxattr = generic_setxattr,
|
|
.getxattr = generic_getxattr,
|
|
.listxattr = generic_listxattr,
|
|
.removexattr = generic_removexattr,
|
|
.check_acl = shmem_check_acl,
|
|
#endif
|
|
};
|
|
|
|
static const struct inode_operations shmem_special_inode_operations = {
|
|
#ifdef CONFIG_TMPFS_POSIX_ACL
|
|
.setattr = shmem_notify_change,
|
|
.setxattr = generic_setxattr,
|
|
.getxattr = generic_getxattr,
|
|
.listxattr = generic_listxattr,
|
|
.removexattr = generic_removexattr,
|
|
.check_acl = shmem_check_acl,
|
|
#endif
|
|
};
|
|
|
|
static const struct super_operations shmem_ops = {
|
|
.alloc_inode = shmem_alloc_inode,
|
|
.destroy_inode = shmem_destroy_inode,
|
|
#ifdef CONFIG_TMPFS
|
|
.statfs = shmem_statfs,
|
|
.remount_fs = shmem_remount_fs,
|
|
.show_options = shmem_show_options,
|
|
#endif
|
|
.delete_inode = shmem_delete_inode,
|
|
.drop_inode = generic_delete_inode,
|
|
.put_super = shmem_put_super,
|
|
};
|
|
|
|
static const struct vm_operations_struct shmem_vm_ops = {
|
|
.fault = shmem_fault,
|
|
#ifdef CONFIG_NUMA
|
|
.set_policy = shmem_set_policy,
|
|
.get_policy = shmem_get_policy,
|
|
#endif
|
|
};
|
|
|
|
|
|
static int shmem_get_sb(struct file_system_type *fs_type,
|
|
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
|
|
{
|
|
return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
|
|
}
|
|
|
|
static struct file_system_type tmpfs_fs_type = {
|
|
.owner = THIS_MODULE,
|
|
.name = "tmpfs",
|
|
.get_sb = shmem_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
int __init init_tmpfs(void)
|
|
{
|
|
int error;
|
|
|
|
error = bdi_init(&shmem_backing_dev_info);
|
|
if (error)
|
|
goto out4;
|
|
|
|
error = init_inodecache();
|
|
if (error)
|
|
goto out3;
|
|
|
|
error = register_filesystem(&tmpfs_fs_type);
|
|
if (error) {
|
|
printk(KERN_ERR "Could not register tmpfs\n");
|
|
goto out2;
|
|
}
|
|
|
|
shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
|
|
tmpfs_fs_type.name, NULL);
|
|
if (IS_ERR(shm_mnt)) {
|
|
error = PTR_ERR(shm_mnt);
|
|
printk(KERN_ERR "Could not kern_mount tmpfs\n");
|
|
goto out1;
|
|
}
|
|
return 0;
|
|
|
|
out1:
|
|
unregister_filesystem(&tmpfs_fs_type);
|
|
out2:
|
|
destroy_inodecache();
|
|
out3:
|
|
bdi_destroy(&shmem_backing_dev_info);
|
|
out4:
|
|
shm_mnt = ERR_PTR(error);
|
|
return error;
|
|
}
|
|
|
|
#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.
|
|
*/
|
|
|
|
#include <linux/ramfs.h>
|
|
|
|
static struct file_system_type tmpfs_fs_type = {
|
|
.name = "tmpfs",
|
|
.get_sb = ramfs_get_sb,
|
|
.kill_sb = kill_litter_super,
|
|
};
|
|
|
|
int __init init_tmpfs(void)
|
|
{
|
|
BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
|
|
|
|
shm_mnt = kern_mount(&tmpfs_fs_type);
|
|
BUG_ON(IS_ERR(shm_mnt));
|
|
|
|
return 0;
|
|
}
|
|
|
|
int shmem_unuse(swp_entry_t entry, struct page *page)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
int shmem_lock(struct file *file, int lock, struct user_struct *user)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#define shmem_vm_ops generic_file_vm_ops
|
|
#define shmem_file_operations ramfs_file_operations
|
|
#define shmem_get_inode(sb, mode, dev, flags) ramfs_get_inode(sb, mode, dev)
|
|
#define shmem_acct_size(flags, size) 0
|
|
#define shmem_unacct_size(flags, size) do {} while (0)
|
|
#define SHMEM_MAX_BYTES MAX_LFS_FILESIZE
|
|
|
|
#endif /* CONFIG_SHMEM */
|
|
|
|
/* common code */
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
int error;
|
|
struct file *file;
|
|
struct inode *inode;
|
|
struct dentry *dentry, *root;
|
|
struct qstr this;
|
|
|
|
if (IS_ERR(shm_mnt))
|
|
return (void *)shm_mnt;
|
|
|
|
if (size < 0 || size > SHMEM_MAX_BYTES)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
if (shmem_acct_size(flags, size))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
error = -ENOMEM;
|
|
this.name = name;
|
|
this.len = strlen(name);
|
|
this.hash = 0; /* will go */
|
|
root = shm_mnt->mnt_root;
|
|
dentry = d_alloc(root, &this);
|
|
if (!dentry)
|
|
goto put_memory;
|
|
|
|
error = -ENFILE;
|
|
file = get_empty_filp();
|
|
if (!file)
|
|
goto put_dentry;
|
|
|
|
error = -ENOSPC;
|
|
inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0, flags);
|
|
if (!inode)
|
|
goto close_file;
|
|
|
|
d_instantiate(dentry, inode);
|
|
inode->i_size = size;
|
|
inode->i_nlink = 0; /* It is unlinked */
|
|
init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
|
|
&shmem_file_operations);
|
|
|
|
#ifndef CONFIG_MMU
|
|
error = ramfs_nommu_expand_for_mapping(inode, size);
|
|
if (error)
|
|
goto close_file;
|
|
#endif
|
|
ima_counts_get(file);
|
|
return file;
|
|
|
|
close_file:
|
|
put_filp(file);
|
|
put_dentry:
|
|
dput(dentry);
|
|
put_memory:
|
|
shmem_unacct_size(flags, size);
|
|
return ERR_PTR(error);
|
|
}
|
|
EXPORT_SYMBOL_GPL(shmem_file_setup);
|
|
|
|
/**
|
|
* shmem_zero_setup - setup a shared anonymous mapping
|
|
* @vma: the vma to be mmapped is prepared by do_mmap_pgoff
|
|
*/
|
|
int shmem_zero_setup(struct vm_area_struct *vma)
|
|
{
|
|
struct file *file;
|
|
loff_t size = vma->vm_end - vma->vm_start;
|
|
|
|
file = shmem_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;
|
|
return 0;
|
|
}
|