| /* |
| * Resizable virtual memory filesystem for Linux. |
| * |
| * Copyright (C) 2000 Linus Torvalds. |
| * 2000 Transmeta Corp. |
| * 2000-2001 Christoph Rohland |
| * 2000-2001 SAP AG |
| * 2002 Red Hat Inc. |
| * Copyright (C) 2002-2011 Hugh Dickins. |
| * Copyright (C) 2011 Google Inc. |
| * Copyright (C) 2002-2005 VERITAS Software Corporation. |
| * Copyright (C) 2004 Andi Kleen, SuSE Labs |
| * |
| * Extended attribute support for tmpfs: |
| * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> |
| * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
| * |
| * tiny-shmem: |
| * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include <linux/fs.h> |
| #include <linux/init.h> |
| #include <linux/vfs.h> |
| #include <linux/mount.h> |
| #include <linux/ramfs.h> |
| #include <linux/pagemap.h> |
| #include <linux/file.h> |
| #include <linux/mm.h> |
| #include <linux/sched/signal.h> |
| #include <linux/export.h> |
| #include <linux/swap.h> |
| #include <linux/uio.h> |
| #include <linux/khugepaged.h> |
| |
| #include <asm/tlbflush.h> /* for arch/microblaze update_mmu_cache() */ |
| |
| static struct vfsmount *shm_mnt; |
| |
| #ifdef CONFIG_SHMEM |
| /* |
| * This virtual memory filesystem is heavily based on the ramfs. It |
| * extends ramfs by the ability to use swap and honor resource limits |
| * which makes it a completely usable filesystem. |
| */ |
| |
| #include <linux/xattr.h> |
| #include <linux/exportfs.h> |
| #include <linux/posix_acl.h> |
| #include <linux/posix_acl_xattr.h> |
| #include <linux/mman.h> |
| #include <linux/string.h> |
| #include <linux/slab.h> |
| #include <linux/backing-dev.h> |
| #include <linux/shmem_fs.h> |
| #include <linux/writeback.h> |
| #include <linux/blkdev.h> |
| #include <linux/pagevec.h> |
| #include <linux/percpu_counter.h> |
| #include <linux/falloc.h> |
| #include <linux/splice.h> |
| #include <linux/security.h> |
| #include <linux/swapops.h> |
| #include <linux/mempolicy.h> |
| #include <linux/namei.h> |
| #include <linux/ctype.h> |
| #include <linux/migrate.h> |
| #include <linux/highmem.h> |
| #include <linux/seq_file.h> |
| #include <linux/magic.h> |
| #include <linux/syscalls.h> |
| #include <linux/fcntl.h> |
| #include <uapi/linux/memfd.h> |
| #include <linux/userfaultfd_k.h> |
| #include <linux/rmap.h> |
| #include <linux/uuid.h> |
| |
| #include <linux/uaccess.h> |
| #include <asm/pgtable.h> |
| |
| #include "internal.h" |
| |
| #define BLOCKS_PER_PAGE (PAGE_SIZE/512) |
| #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) |
| |
| /* Pretend that each entry is of this size in directory's i_size */ |
| #define BOGO_DIRENT_SIZE 20 |
| |
| /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ |
| #define SHORT_SYMLINK_LEN 128 |
| |
| /* |
| * shmem_fallocate communicates with shmem_fault or shmem_writepage via |
| * inode->i_private (with i_mutex making sure that it has only one user at |
| * a time): we would prefer not to enlarge the shmem inode just for that. |
| */ |
| struct shmem_falloc { |
| wait_queue_head_t *waitq; /* faults into hole wait for punch to end */ |
| pgoff_t start; /* start of range currently being fallocated */ |
| pgoff_t next; /* the next page offset to be fallocated */ |
| pgoff_t nr_falloced; /* how many new pages have been fallocated */ |
| pgoff_t nr_unswapped; /* how often writepage refused to swap out */ |
| }; |
| |
| #ifdef CONFIG_TMPFS |
| static unsigned long shmem_default_max_blocks(void) |
| { |
| return totalram_pages / 2; |
| } |
| |
| static unsigned long shmem_default_max_inodes(void) |
| { |
| return min(totalram_pages - totalhigh_pages, totalram_pages / 2); |
| } |
| #endif |
| |
| static bool shmem_should_replace_page(struct page *page, gfp_t gfp); |
| static int shmem_replace_page(struct page **pagep, gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index); |
| static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp, |
| gfp_t gfp, struct vm_area_struct *vma, |
| struct vm_fault *vmf, int *fault_type); |
| |
| int shmem_getpage(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp) |
| { |
| return shmem_getpage_gfp(inode, index, pagep, sgp, |
| mapping_gfp_mask(inode->i_mapping), NULL, NULL, NULL); |
| } |
| |
| static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
| { |
| return sb->s_fs_info; |
| } |
| |
| /* |
| * shmem_file_setup pre-accounts the whole fixed size of a VM object, |
| * for shared memory and for shared anonymous (/dev/zero) mappings |
| * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), |
| * consistent with the pre-accounting of private mappings ... |
| */ |
| static inline int shmem_acct_size(unsigned long flags, loff_t size) |
| { |
| return (flags & VM_NORESERVE) ? |
| 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); |
| } |
| |
| static inline void shmem_unacct_size(unsigned long flags, loff_t size) |
| { |
| if (!(flags & VM_NORESERVE)) |
| vm_unacct_memory(VM_ACCT(size)); |
| } |
| |
| static inline int shmem_reacct_size(unsigned long flags, |
| loff_t oldsize, loff_t newsize) |
| { |
| if (!(flags & VM_NORESERVE)) { |
| if (VM_ACCT(newsize) > VM_ACCT(oldsize)) |
| return security_vm_enough_memory_mm(current->mm, |
| VM_ACCT(newsize) - VM_ACCT(oldsize)); |
| else if (VM_ACCT(newsize) < VM_ACCT(oldsize)) |
| vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize)); |
| } |
| return 0; |
| } |
| |
| /* |
| * ... whereas tmpfs objects are accounted incrementally as |
| * pages are allocated, in order to allow large sparse files. |
| * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, |
| * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. |
| */ |
| static inline int shmem_acct_block(unsigned long flags, long pages) |
| { |
| if (!(flags & VM_NORESERVE)) |
| return 0; |
| |
| return security_vm_enough_memory_mm(current->mm, |
| pages * VM_ACCT(PAGE_SIZE)); |
| } |
| |
| static inline void shmem_unacct_blocks(unsigned long flags, long pages) |
| { |
| if (flags & VM_NORESERVE) |
| vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); |
| } |
| |
| static const struct super_operations shmem_ops; |
| static const struct address_space_operations shmem_aops; |
| static const struct file_operations shmem_file_operations; |
| static const struct inode_operations shmem_inode_operations; |
| static const struct inode_operations shmem_dir_inode_operations; |
| static const struct inode_operations shmem_special_inode_operations; |
| static const struct vm_operations_struct shmem_vm_ops; |
| static struct file_system_type shmem_fs_type; |
| |
| bool vma_is_shmem(struct vm_area_struct *vma) |
| { |
| return vma->vm_ops == &shmem_vm_ops; |
| } |
| |
| static LIST_HEAD(shmem_swaplist); |
| static DEFINE_MUTEX(shmem_swaplist_mutex); |
| |
| static int shmem_reserve_inode(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| if (sbinfo->max_inodes) { |
| spin_lock(&sbinfo->stat_lock); |
| if (!sbinfo->free_inodes) { |
| spin_unlock(&sbinfo->stat_lock); |
| return -ENOSPC; |
| } |
| sbinfo->free_inodes--; |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| return 0; |
| } |
| |
| static void shmem_free_inode(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| if (sbinfo->max_inodes) { |
| spin_lock(&sbinfo->stat_lock); |
| sbinfo->free_inodes++; |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| } |
| |
| /** |
| * shmem_recalc_inode - recalculate the block usage of an inode |
| * @inode: inode to recalc |
| * |
| * We have to calculate the free blocks since the mm can drop |
| * undirtied hole pages behind our back. |
| * |
| * But normally info->alloced == inode->i_mapping->nrpages + info->swapped |
| * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) |
| * |
| * It has to be called with the spinlock held. |
| */ |
| static void shmem_recalc_inode(struct inode *inode) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| long freed; |
| |
| freed = info->alloced - info->swapped - inode->i_mapping->nrpages; |
| if (freed > 0) { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| if (sbinfo->max_blocks) |
| percpu_counter_add(&sbinfo->used_blocks, -freed); |
| info->alloced -= freed; |
| inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
| shmem_unacct_blocks(info->flags, freed); |
| } |
| } |
| |
| bool shmem_charge(struct inode *inode, long pages) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| unsigned long flags; |
| |
| if (shmem_acct_block(info->flags, pages)) |
| return false; |
| spin_lock_irqsave(&info->lock, flags); |
| info->alloced += pages; |
| inode->i_blocks += pages * BLOCKS_PER_PAGE; |
| shmem_recalc_inode(inode); |
| spin_unlock_irqrestore(&info->lock, flags); |
| inode->i_mapping->nrpages += pages; |
| |
| if (!sbinfo->max_blocks) |
| return true; |
| if (percpu_counter_compare(&sbinfo->used_blocks, |
| sbinfo->max_blocks - pages) > 0) { |
| inode->i_mapping->nrpages -= pages; |
| spin_lock_irqsave(&info->lock, flags); |
| info->alloced -= pages; |
| shmem_recalc_inode(inode); |
| spin_unlock_irqrestore(&info->lock, flags); |
| shmem_unacct_blocks(info->flags, pages); |
| return false; |
| } |
| percpu_counter_add(&sbinfo->used_blocks, pages); |
| return true; |
| } |
| |
| void shmem_uncharge(struct inode *inode, long pages) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&info->lock, flags); |
| info->alloced -= pages; |
| inode->i_blocks -= pages * BLOCKS_PER_PAGE; |
| shmem_recalc_inode(inode); |
| spin_unlock_irqrestore(&info->lock, flags); |
| |
| if (sbinfo->max_blocks) |
| percpu_counter_sub(&sbinfo->used_blocks, pages); |
| shmem_unacct_blocks(info->flags, pages); |
| } |
| |
| /* |
| * Replace item expected in radix tree by a new item, while holding tree lock. |
| */ |
| static int shmem_radix_tree_replace(struct address_space *mapping, |
| pgoff_t index, void *expected, void *replacement) |
| { |
| struct radix_tree_node *node; |
| void **pslot; |
| void *item; |
| |
| VM_BUG_ON(!expected); |
| VM_BUG_ON(!replacement); |
| item = __radix_tree_lookup(&mapping->page_tree, index, &node, &pslot); |
| if (!item) |
| return -ENOENT; |
| if (item != expected) |
| return -ENOENT; |
| __radix_tree_replace(&mapping->page_tree, node, pslot, |
| replacement, NULL, NULL); |
| return 0; |
| } |
| |
| /* |
| * Sometimes, before we decide whether to proceed or to fail, we must check |
| * that an entry was not already brought back from swap by a racing thread. |
| * |
| * Checking page is not enough: by the time a SwapCache page is locked, it |
| * might be reused, and again be SwapCache, using the same swap as before. |
| */ |
| static bool shmem_confirm_swap(struct address_space *mapping, |
| pgoff_t index, swp_entry_t swap) |
| { |
| void *item; |
| |
| rcu_read_lock(); |
| item = radix_tree_lookup(&mapping->page_tree, index); |
| rcu_read_unlock(); |
| return item == swp_to_radix_entry(swap); |
| } |
| |
| /* |
| * Definitions for "huge tmpfs": tmpfs mounted with the huge= option |
| * |
| * SHMEM_HUGE_NEVER: |
| * disables huge pages for the mount; |
| * SHMEM_HUGE_ALWAYS: |
| * enables huge pages for the mount; |
| * SHMEM_HUGE_WITHIN_SIZE: |
| * only allocate huge pages if the page will be fully within i_size, |
| * also respect fadvise()/madvise() hints; |
| * SHMEM_HUGE_ADVISE: |
| * only allocate huge pages if requested with fadvise()/madvise(); |
| */ |
| |
| #define SHMEM_HUGE_NEVER 0 |
| #define SHMEM_HUGE_ALWAYS 1 |
| #define SHMEM_HUGE_WITHIN_SIZE 2 |
| #define SHMEM_HUGE_ADVISE 3 |
| |
| /* |
| * Special values. |
| * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled: |
| * |
| * SHMEM_HUGE_DENY: |
| * disables huge on shm_mnt and all mounts, for emergency use; |
| * SHMEM_HUGE_FORCE: |
| * enables huge on shm_mnt and all mounts, w/o needing option, for testing; |
| * |
| */ |
| #define SHMEM_HUGE_DENY (-1) |
| #define SHMEM_HUGE_FORCE (-2) |
| |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| /* ifdef here to avoid bloating shmem.o when not necessary */ |
| |
| int shmem_huge __read_mostly; |
| |
| #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS) |
| static int shmem_parse_huge(const char *str) |
| { |
| if (!strcmp(str, "never")) |
| return SHMEM_HUGE_NEVER; |
| if (!strcmp(str, "always")) |
| return SHMEM_HUGE_ALWAYS; |
| if (!strcmp(str, "within_size")) |
| return SHMEM_HUGE_WITHIN_SIZE; |
| if (!strcmp(str, "advise")) |
| return SHMEM_HUGE_ADVISE; |
| if (!strcmp(str, "deny")) |
| return SHMEM_HUGE_DENY; |
| if (!strcmp(str, "force")) |
| return SHMEM_HUGE_FORCE; |
| return -EINVAL; |
| } |
| |
| static const char *shmem_format_huge(int huge) |
| { |
| switch (huge) { |
| case SHMEM_HUGE_NEVER: |
| return "never"; |
| case SHMEM_HUGE_ALWAYS: |
| return "always"; |
| case SHMEM_HUGE_WITHIN_SIZE: |
| return "within_size"; |
| case SHMEM_HUGE_ADVISE: |
| return "advise"; |
| case SHMEM_HUGE_DENY: |
| return "deny"; |
| case SHMEM_HUGE_FORCE: |
| return "force"; |
| default: |
| VM_BUG_ON(1); |
| return "bad_val"; |
| } |
| } |
| #endif |
| |
| static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, |
| struct shrink_control *sc, unsigned long nr_to_split) |
| { |
| LIST_HEAD(list), *pos, *next; |
| LIST_HEAD(to_remove); |
| struct inode *inode; |
| struct shmem_inode_info *info; |
| struct page *page; |
| unsigned long batch = sc ? sc->nr_to_scan : 128; |
| int removed = 0, split = 0; |
| |
| if (list_empty(&sbinfo->shrinklist)) |
| return SHRINK_STOP; |
| |
| spin_lock(&sbinfo->shrinklist_lock); |
| list_for_each_safe(pos, next, &sbinfo->shrinklist) { |
| info = list_entry(pos, struct shmem_inode_info, shrinklist); |
| |
| /* pin the inode */ |
| inode = igrab(&info->vfs_inode); |
| |
| /* inode is about to be evicted */ |
| if (!inode) { |
| list_del_init(&info->shrinklist); |
| removed++; |
| goto next; |
| } |
| |
| /* Check if there's anything to gain */ |
| if (round_up(inode->i_size, PAGE_SIZE) == |
| round_up(inode->i_size, HPAGE_PMD_SIZE)) { |
| list_move(&info->shrinklist, &to_remove); |
| removed++; |
| goto next; |
| } |
| |
| list_move(&info->shrinklist, &list); |
| next: |
| if (!--batch) |
| break; |
| } |
| spin_unlock(&sbinfo->shrinklist_lock); |
| |
| list_for_each_safe(pos, next, &to_remove) { |
| info = list_entry(pos, struct shmem_inode_info, shrinklist); |
| inode = &info->vfs_inode; |
| list_del_init(&info->shrinklist); |
| iput(inode); |
| } |
| |
| list_for_each_safe(pos, next, &list) { |
| int ret; |
| |
| info = list_entry(pos, struct shmem_inode_info, shrinklist); |
| inode = &info->vfs_inode; |
| |
| if (nr_to_split && split >= nr_to_split) { |
| iput(inode); |
| continue; |
| } |
| |
| page = find_lock_page(inode->i_mapping, |
| (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT); |
| if (!page) |
| goto drop; |
| |
| if (!PageTransHuge(page)) { |
| unlock_page(page); |
| put_page(page); |
| goto drop; |
| } |
| |
| ret = split_huge_page(page); |
| unlock_page(page); |
| put_page(page); |
| |
| if (ret) { |
| /* split failed: leave it on the list */ |
| iput(inode); |
| continue; |
| } |
| |
| split++; |
| drop: |
| list_del_init(&info->shrinklist); |
| removed++; |
| iput(inode); |
| } |
| |
| spin_lock(&sbinfo->shrinklist_lock); |
| list_splice_tail(&list, &sbinfo->shrinklist); |
| sbinfo->shrinklist_len -= removed; |
| spin_unlock(&sbinfo->shrinklist_lock); |
| |
| return split; |
| } |
| |
| static long shmem_unused_huge_scan(struct super_block *sb, |
| struct shrink_control *sc) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| |
| if (!READ_ONCE(sbinfo->shrinklist_len)) |
| return SHRINK_STOP; |
| |
| return shmem_unused_huge_shrink(sbinfo, sc, 0); |
| } |
| |
| static long shmem_unused_huge_count(struct super_block *sb, |
| struct shrink_control *sc) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| return READ_ONCE(sbinfo->shrinklist_len); |
| } |
| #else /* !CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
| |
| #define shmem_huge SHMEM_HUGE_DENY |
| |
| static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, |
| struct shrink_control *sc, unsigned long nr_to_split) |
| { |
| return 0; |
| } |
| #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
| |
| /* |
| * Like add_to_page_cache_locked, but error if expected item has gone. |
| */ |
| static int shmem_add_to_page_cache(struct page *page, |
| struct address_space *mapping, |
| pgoff_t index, void *expected) |
| { |
| int error, nr = hpage_nr_pages(page); |
| |
| VM_BUG_ON_PAGE(PageTail(page), page); |
| VM_BUG_ON_PAGE(index != round_down(index, nr), page); |
| VM_BUG_ON_PAGE(!PageLocked(page), page); |
| VM_BUG_ON_PAGE(!PageSwapBacked(page), page); |
| VM_BUG_ON(expected && PageTransHuge(page)); |
| |
| page_ref_add(page, nr); |
| page->mapping = mapping; |
| page->index = index; |
| |
| spin_lock_irq(&mapping->tree_lock); |
| if (PageTransHuge(page)) { |
| void __rcu **results; |
| pgoff_t idx; |
| int i; |
| |
| error = 0; |
| if (radix_tree_gang_lookup_slot(&mapping->page_tree, |
| &results, &idx, index, 1) && |
| idx < index + HPAGE_PMD_NR) { |
| error = -EEXIST; |
| } |
| |
| if (!error) { |
| for (i = 0; i < HPAGE_PMD_NR; i++) { |
| error = radix_tree_insert(&mapping->page_tree, |
| index + i, page + i); |
| VM_BUG_ON(error); |
| } |
| count_vm_event(THP_FILE_ALLOC); |
| } |
| } else if (!expected) { |
| error = radix_tree_insert(&mapping->page_tree, index, page); |
| } else { |
| error = shmem_radix_tree_replace(mapping, index, expected, |
| page); |
| } |
| |
| if (!error) { |
| mapping->nrpages += nr; |
| if (PageTransHuge(page)) |
| __inc_node_page_state(page, NR_SHMEM_THPS); |
| __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); |
| __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr); |
| spin_unlock_irq(&mapping->tree_lock); |
| } else { |
| page->mapping = NULL; |
| spin_unlock_irq(&mapping->tree_lock); |
| page_ref_sub(page, nr); |
| } |
| return error; |
| } |
| |
| /* |
| * Like delete_from_page_cache, but substitutes swap for page. |
| */ |
| static void shmem_delete_from_page_cache(struct page *page, void *radswap) |
| { |
| struct address_space *mapping = page->mapping; |
| int error; |
| |
| VM_BUG_ON_PAGE(PageCompound(page), page); |
| |
| spin_lock_irq(&mapping->tree_lock); |
| error = shmem_radix_tree_replace(mapping, page->index, page, radswap); |
| page->mapping = NULL; |
| mapping->nrpages--; |
| __dec_node_page_state(page, NR_FILE_PAGES); |
| __dec_node_page_state(page, NR_SHMEM); |
| spin_unlock_irq(&mapping->tree_lock); |
| put_page(page); |
| BUG_ON(error); |
| } |
| |
| /* |
| * Remove swap entry from radix tree, free the swap and its page cache. |
| */ |
| static int shmem_free_swap(struct address_space *mapping, |
| pgoff_t index, void *radswap) |
| { |
| void *old; |
| |
| spin_lock_irq(&mapping->tree_lock); |
| old = radix_tree_delete_item(&mapping->page_tree, index, radswap); |
| spin_unlock_irq(&mapping->tree_lock); |
| if (old != radswap) |
| return -ENOENT; |
| free_swap_and_cache(radix_to_swp_entry(radswap)); |
| return 0; |
| } |
| |
| /* |
| * Determine (in bytes) how many of the shmem object's pages mapped by the |
| * given offsets are swapped out. |
| * |
| * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, |
| * as long as the inode doesn't go away and racy results are not a problem. |
| */ |
| unsigned long shmem_partial_swap_usage(struct address_space *mapping, |
| pgoff_t start, pgoff_t end) |
| { |
| struct radix_tree_iter iter; |
| void **slot; |
| struct page *page; |
| unsigned long swapped = 0; |
| |
| rcu_read_lock(); |
| |
| radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { |
| if (iter.index >= end) |
| break; |
| |
| page = radix_tree_deref_slot(slot); |
| |
| if (radix_tree_deref_retry(page)) { |
| slot = radix_tree_iter_retry(&iter); |
| continue; |
| } |
| |
| if (radix_tree_exceptional_entry(page)) |
| swapped++; |
| |
| if (need_resched()) { |
| slot = radix_tree_iter_resume(slot, &iter); |
| cond_resched_rcu(); |
| } |
| } |
| |
| rcu_read_unlock(); |
| |
| return swapped << PAGE_SHIFT; |
| } |
| |
| /* |
| * Determine (in bytes) how many of the shmem object's pages mapped by the |
| * given vma is swapped out. |
| * |
| * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, |
| * as long as the inode doesn't go away and racy results are not a problem. |
| */ |
| unsigned long shmem_swap_usage(struct vm_area_struct *vma) |
| { |
| struct inode *inode = file_inode(vma->vm_file); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct address_space *mapping = inode->i_mapping; |
| unsigned long swapped; |
| |
| /* Be careful as we don't hold info->lock */ |
| swapped = READ_ONCE(info->swapped); |
| |
| /* |
| * The easier cases are when the shmem object has nothing in swap, or |
| * the vma maps it whole. Then we can simply use the stats that we |
| * already track. |
| */ |
| if (!swapped) |
| return 0; |
| |
| if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size) |
| return swapped << PAGE_SHIFT; |
| |
| /* Here comes the more involved part */ |
| return shmem_partial_swap_usage(mapping, |
| linear_page_index(vma, vma->vm_start), |
| linear_page_index(vma, vma->vm_end)); |
| } |
| |
| /* |
| * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. |
| */ |
| void shmem_unlock_mapping(struct address_space *mapping) |
| { |
| struct pagevec pvec; |
| pgoff_t indices[PAGEVEC_SIZE]; |
| pgoff_t index = 0; |
| |
| pagevec_init(&pvec, 0); |
| /* |
| * Minor point, but we might as well stop if someone else SHM_LOCKs it. |
| */ |
| while (!mapping_unevictable(mapping)) { |
| /* |
| * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it |
| * has finished, if it hits a row of PAGEVEC_SIZE swap entries. |
| */ |
| pvec.nr = find_get_entries(mapping, index, |
| PAGEVEC_SIZE, pvec.pages, indices); |
| if (!pvec.nr) |
| break; |
| index = indices[pvec.nr - 1] + 1; |
| pagevec_remove_exceptionals(&pvec); |
| check_move_unevictable_pages(pvec.pages, pvec.nr); |
| pagevec_release(&pvec); |
| cond_resched(); |
| } |
| } |
| |
| /* |
| * Remove range of pages and swap entries from radix tree, and free them. |
| * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. |
| */ |
| static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, |
| bool unfalloc) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| pgoff_t end = (lend + 1) >> PAGE_SHIFT; |
| unsigned int partial_start = lstart & (PAGE_SIZE - 1); |
| unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1); |
| struct pagevec pvec; |
| pgoff_t indices[PAGEVEC_SIZE]; |
| long nr_swaps_freed = 0; |
| pgoff_t index; |
| int i; |
| |
| if (lend == -1) |
| end = -1; /* unsigned, so actually very big */ |
| |
| pagevec_init(&pvec, 0); |
| index = start; |
| while (index < end) { |
| pvec.nr = find_get_entries(mapping, index, |
| min(end - index, (pgoff_t)PAGEVEC_SIZE), |
| pvec.pages, indices); |
| if (!pvec.nr) |
| break; |
| for (i = 0; i < pagevec_count(&pvec); i++) { |
| struct page *page = pvec.pages[i]; |
| |
| index = indices[i]; |
| if (index >= end) |
| break; |
| |
| if (radix_tree_exceptional_entry(page)) { |
| if (unfalloc) |
| continue; |
| nr_swaps_freed += !shmem_free_swap(mapping, |
| index, page); |
| continue; |
| } |
| |
| VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page); |
| |
| if (!trylock_page(page)) |
| continue; |
| |
| if (PageTransTail(page)) { |
| /* Middle of THP: zero out the page */ |
| clear_highpage(page); |
| unlock_page(page); |
| continue; |
| } else if (PageTransHuge(page)) { |
| if (index == round_down(end, HPAGE_PMD_NR)) { |
| /* |
| * Range ends in the middle of THP: |
| * zero out the page |
| */ |
| clear_highpage(page); |
| unlock_page(page); |
| continue; |
| } |
| index += HPAGE_PMD_NR - 1; |
| i += HPAGE_PMD_NR - 1; |
| } |
| |
| if (!unfalloc || !PageUptodate(page)) { |
| VM_BUG_ON_PAGE(PageTail(page), page); |
| if (page_mapping(page) == mapping) { |
| VM_BUG_ON_PAGE(PageWriteback(page), page); |
| truncate_inode_page(mapping, page); |
| } |
| } |
| unlock_page(page); |
| } |
| pagevec_remove_exceptionals(&pvec); |
| pagevec_release(&pvec); |
| cond_resched(); |
| index++; |
| } |
| |
| if (partial_start) { |
| struct page *page = NULL; |
| shmem_getpage(inode, start - 1, &page, SGP_READ); |
| if (page) { |
| unsigned int top = PAGE_SIZE; |
| if (start > end) { |
| top = partial_end; |
| partial_end = 0; |
| } |
| zero_user_segment(page, partial_start, top); |
| set_page_dirty(page); |
| unlock_page(page); |
| put_page(page); |
| } |
| } |
| if (partial_end) { |
| struct page *page = NULL; |
| shmem_getpage(inode, end, &page, SGP_READ); |
| if (page) { |
| zero_user_segment(page, 0, partial_end); |
| set_page_dirty(page); |
| unlock_page(page); |
| put_page(page); |
| } |
| } |
| if (start >= end) |
| return; |
| |
| index = start; |
| while (index < end) { |
| cond_resched(); |
| |
| pvec.nr = find_get_entries(mapping, index, |
| min(end - index, (pgoff_t)PAGEVEC_SIZE), |
| pvec.pages, indices); |
| if (!pvec.nr) { |
| /* If all gone or hole-punch or unfalloc, we're done */ |
| if (index == start || end != -1) |
| break; |
| /* But if truncating, restart to make sure all gone */ |
| index = start; |
| continue; |
| } |
| for (i = 0; i < pagevec_count(&pvec); i++) { |
| struct page *page = pvec.pages[i]; |
| |
| index = indices[i]; |
| if (index >= end) |
| break; |
| |
| if (radix_tree_exceptional_entry(page)) { |
| if (unfalloc) |
| continue; |
| if (shmem_free_swap(mapping, index, page)) { |
| /* Swap was replaced by page: retry */ |
| index--; |
| break; |
| } |
| nr_swaps_freed++; |
| continue; |
| } |
| |
| lock_page(page); |
| |
| if (PageTransTail(page)) { |
| /* Middle of THP: zero out the page */ |
| clear_highpage(page); |
| unlock_page(page); |
| /* |
| * Partial thp truncate due 'start' in middle |
| * of THP: don't need to look on these pages |
| * again on !pvec.nr restart. |
| */ |
| if (index != round_down(end, HPAGE_PMD_NR)) |
| start++; |
| continue; |
| } else if (PageTransHuge(page)) { |
| if (index == round_down(end, HPAGE_PMD_NR)) { |
| /* |
| * Range ends in the middle of THP: |
| * zero out the page |
| */ |
| clear_highpage(page); |
| unlock_page(page); |
| continue; |
| } |
| index += HPAGE_PMD_NR - 1; |
| i += HPAGE_PMD_NR - 1; |
| } |
| |
| if (!unfalloc || !PageUptodate(page)) { |
| VM_BUG_ON_PAGE(PageTail(page), page); |
| if (page_mapping(page) == mapping) { |
| VM_BUG_ON_PAGE(PageWriteback(page), page); |
| truncate_inode_page(mapping, page); |
| } else { |
| /* Page was replaced by swap: retry */ |
| unlock_page(page); |
| index--; |
| break; |
| } |
| } |
| unlock_page(page); |
| } |
| pagevec_remove_exceptionals(&pvec); |
| pagevec_release(&pvec); |
| index++; |
| } |
| |
| spin_lock_irq(&info->lock); |
| info->swapped -= nr_swaps_freed; |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| } |
| |
| void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
| { |
| shmem_undo_range(inode, lstart, lend, false); |
| inode->i_ctime = inode->i_mtime = current_time(inode); |
| } |
| EXPORT_SYMBOL_GPL(shmem_truncate_range); |
| |
| static int shmem_getattr(const struct path *path, struct kstat *stat, |
| u32 request_mask, unsigned int query_flags) |
| { |
| struct inode *inode = path->dentry->d_inode; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| |
| if (info->alloced - info->swapped != inode->i_mapping->nrpages) { |
| spin_lock_irq(&info->lock); |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| } |
| generic_fillattr(inode, stat); |
| return 0; |
| } |
| |
| static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| struct inode *inode = d_inode(dentry); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| int error; |
| |
| error = setattr_prepare(dentry, attr); |
| if (error) |
| return error; |
| |
| if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
| loff_t oldsize = inode->i_size; |
| loff_t newsize = attr->ia_size; |
| |
| /* protected by i_mutex */ |
| if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || |
| (newsize > oldsize && (info->seals & F_SEAL_GROW))) |
| return -EPERM; |
| |
| if (newsize != oldsize) { |
| error = shmem_reacct_size(SHMEM_I(inode)->flags, |
| oldsize, newsize); |
| if (error) |
| return error; |
| i_size_write(inode, newsize); |
| inode->i_ctime = inode->i_mtime = current_time(inode); |
| } |
| if (newsize <= oldsize) { |
| loff_t holebegin = round_up(newsize, PAGE_SIZE); |
| if (oldsize > holebegin) |
| unmap_mapping_range(inode->i_mapping, |
| holebegin, 0, 1); |
| if (info->alloced) |
| shmem_truncate_range(inode, |
| newsize, (loff_t)-1); |
| /* unmap again to remove racily COWed private pages */ |
| if (oldsize > holebegin) |
| unmap_mapping_range(inode->i_mapping, |
| holebegin, 0, 1); |
| |
| /* |
| * Part of the huge page can be beyond i_size: subject |
| * to shrink under memory pressure. |
| */ |
| if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { |
| spin_lock(&sbinfo->shrinklist_lock); |
| if (list_empty(&info->shrinklist)) { |
| list_add_tail(&info->shrinklist, |
| &sbinfo->shrinklist); |
| sbinfo->shrinklist_len++; |
| } |
| spin_unlock(&sbinfo->shrinklist_lock); |
| } |
| } |
| } |
| |
| setattr_copy(inode, attr); |
| if (attr->ia_valid & ATTR_MODE) |
| error = posix_acl_chmod(inode, inode->i_mode); |
| return error; |
| } |
| |
| static void shmem_evict_inode(struct inode *inode) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| |
| if (inode->i_mapping->a_ops == &shmem_aops) { |
| shmem_unacct_size(info->flags, inode->i_size); |
| inode->i_size = 0; |
| shmem_truncate_range(inode, 0, (loff_t)-1); |
| if (!list_empty(&info->shrinklist)) { |
| spin_lock(&sbinfo->shrinklist_lock); |
| if (!list_empty(&info->shrinklist)) { |
| list_del_init(&info->shrinklist); |
| sbinfo->shrinklist_len--; |
| } |
| spin_unlock(&sbinfo->shrinklist_lock); |
| } |
| if (!list_empty(&info->swaplist)) { |
| mutex_lock(&shmem_swaplist_mutex); |
| list_del_init(&info->swaplist); |
| mutex_unlock(&shmem_swaplist_mutex); |
| } |
| } |
| |
| simple_xattrs_free(&info->xattrs); |
| WARN_ON(inode->i_blocks); |
| shmem_free_inode(inode->i_sb); |
| clear_inode(inode); |
| } |
| |
| static unsigned long find_swap_entry(struct radix_tree_root *root, void *item) |
| { |
| struct radix_tree_iter iter; |
| void **slot; |
| unsigned long found = -1; |
| unsigned int checked = 0; |
| |
| rcu_read_lock(); |
| radix_tree_for_each_slot(slot, root, &iter, 0) { |
| if (*slot == item) { |
| found = iter.index; |
| break; |
| } |
| checked++; |
| if ((checked % 4096) != 0) |
| continue; |
| slot = radix_tree_iter_resume(slot, &iter); |
| cond_resched_rcu(); |
| } |
| |
| rcu_read_unlock(); |
| return found; |
| } |
| |
| /* |
| * If swap found in inode, free it and move page from swapcache to filecache. |
| */ |
| static int shmem_unuse_inode(struct shmem_inode_info *info, |
| swp_entry_t swap, struct page **pagep) |
| { |
| struct address_space *mapping = info->vfs_inode.i_mapping; |
| void *radswap; |
| pgoff_t index; |
| gfp_t gfp; |
| int error = 0; |
| |
| radswap = swp_to_radix_entry(swap); |
| index = find_swap_entry(&mapping->page_tree, radswap); |
| if (index == -1) |
| return -EAGAIN; /* tell shmem_unuse we found nothing */ |
| |
| /* |
| * Move _head_ to start search for next from here. |
| * But be careful: shmem_evict_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. |
| */ |
| if (shmem_swaplist.next != &info->swaplist) |
| list_move_tail(&shmem_swaplist, &info->swaplist); |
| |
| gfp = mapping_gfp_mask(mapping); |
| if (shmem_should_replace_page(*pagep, gfp)) { |
| mutex_unlock(&shmem_swaplist_mutex); |
| error = shmem_replace_page(pagep, gfp, info, index); |
| mutex_lock(&shmem_swaplist_mutex); |
| /* |
| * We needed to drop mutex to make that restrictive page |
| * allocation, but the inode might have been freed while we |
| * dropped it: although a racing shmem_evict_inode() cannot |
| * complete without emptying the radix_tree, our page lock |
| * on this swapcache page is not enough to prevent that - |
| * free_swap_and_cache() of our swap entry will only |
| * trylock_page(), removing swap from radix_tree whatever. |
| * |
| * We must not proceed to shmem_add_to_page_cache() if the |
| * inode has been freed, but of course we cannot rely on |
| * inode or mapping or info to check that. However, we can |
| * safely check if our swap entry is still in use (and here |
| * it can't have got reused for another page): if it's still |
| * in use, then the inode cannot have been freed yet, and we |
| * can safely proceed (if it's no longer in use, that tells |
| * nothing about the inode, but we don't need to unuse swap). |
| */ |
| if (!page_swapcount(*pagep)) |
| error = -ENOENT; |
| } |
| |
| /* |
| * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
| * but also to hold up shmem_evict_inode(): so inode cannot be freed |
| * beneath us (pagelock doesn't help until the page is in pagecache). |
| */ |
| if (!error) |
| error = shmem_add_to_page_cache(*pagep, mapping, index, |
| radswap); |
| if (error != -ENOMEM) { |
| /* |
| * Truncation and eviction use free_swap_and_cache(), which |
| * only does trylock page: if we raced, best clean up here. |
| */ |
| delete_from_swap_cache(*pagep); |
| set_page_dirty(*pagep); |
| if (!error) { |
| spin_lock_irq(&info->lock); |
| info->swapped--; |
| spin_unlock_irq(&info->lock); |
| swap_free(swap); |
| } |
| } |
| return error; |
| } |
| |
| /* |
| * Search through swapped inodes to find and replace swap by page. |
| */ |
| int shmem_unuse(swp_entry_t swap, struct page *page) |
| { |
| struct list_head *this, *next; |
| struct shmem_inode_info *info; |
| struct mem_cgroup *memcg; |
| int error = 0; |
| |
| /* |
| * There's a faint possibility that swap page was replaced before |
| * caller locked it: caller will come back later with the right page. |
| */ |
| if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) |
| goto out; |
| |
| /* |
| * Charge page using GFP_KERNEL while we can wait, before taking |
| * the shmem_swaplist_mutex which might hold up shmem_writepage(). |
| * Charged back to the user (not to caller) when swap account is used. |
| */ |
| error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg, |
| false); |
| if (error) |
| goto out; |
| /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
| error = -EAGAIN; |
| |
| mutex_lock(&shmem_swaplist_mutex); |
| list_for_each_safe(this, next, &shmem_swaplist) { |
| info = list_entry(this, struct shmem_inode_info, swaplist); |
| if (info->swapped) |
| error = shmem_unuse_inode(info, swap, &page); |
| else |
| list_del_init(&info->swaplist); |
| cond_resched(); |
| if (error != -EAGAIN) |
| break; |
| /* found nothing in this: move on to search the next */ |
| } |
| mutex_unlock(&shmem_swaplist_mutex); |
| |
| if (error) { |
| if (error != -ENOMEM) |
| error = 0; |
| mem_cgroup_cancel_charge(page, memcg, false); |
| } else |
| mem_cgroup_commit_charge(page, memcg, true, false); |
| out: |
| unlock_page(page); |
| put_page(page); |
| return error; |
| } |
| |
| /* |
| * Move the page from the page cache to the swap cache. |
| */ |
| static int shmem_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct shmem_inode_info *info; |
| struct address_space *mapping; |
| struct inode *inode; |
| swp_entry_t swap; |
| pgoff_t index; |
| |
| VM_BUG_ON_PAGE(PageCompound(page), page); |
| BUG_ON(!PageLocked(page)); |
| mapping = page->mapping; |
| index = page->index; |
| inode = mapping->host; |
| info = SHMEM_I(inode); |
| if (info->flags & VM_LOCKED) |
| goto redirty; |
| if (!total_swap_pages) |
| goto redirty; |
| |
| /* |
| * Our capabilities prevent regular writeback or sync from ever calling |
| * shmem_writepage; but a stacking filesystem might use ->writepage of |
| * its underlying filesystem, in which case tmpfs should write out to |
| * swap only in response to memory pressure, and not for the writeback |
| * threads or sync. |
| */ |
| if (!wbc->for_reclaim) { |
| WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ |
| goto redirty; |
| } |
| |
| /* |
| * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC |
| * value into swapfile.c, the only way we can correctly account for a |
| * fallocated page arriving here is now to initialize it and write it. |
| * |
| * That's okay for a page already fallocated earlier, but if we have |
| * not yet completed the fallocation, then (a) we want to keep track |
| * of this page in case we have to undo it, and (b) it may not be a |
| * good idea to continue anyway, once we're pushing into swap. So |
| * reactivate the page, and let shmem_fallocate() quit when too many. |
| */ |
| if (!PageUptodate(page)) { |
| if (inode->i_private) { |
| struct shmem_falloc *shmem_falloc; |
| spin_lock(&inode->i_lock); |
| shmem_falloc = inode->i_private; |
| if (shmem_falloc && |
| !shmem_falloc->waitq && |
| index >= shmem_falloc->start && |
| index < shmem_falloc->next) |
| shmem_falloc->nr_unswapped++; |
| else |
| shmem_falloc = NULL; |
| spin_unlock(&inode->i_lock); |
| if (shmem_falloc) |
| goto redirty; |
| } |
| clear_highpage(page); |
| flush_dcache_page(page); |
| SetPageUptodate(page); |
| } |
| |
| swap = get_swap_page(); |
| if (!swap.val) |
| goto redirty; |
| |
| if (mem_cgroup_try_charge_swap(page, swap)) |
| goto free_swap; |
| |
| /* |
| * Add inode to shmem_unuse()'s list of swapped-out inodes, |
| * if it's not already there. Do it now before the page is |
| * moved to swap cache, when its pagelock no longer protects |
| * the inode from eviction. But don't unlock the mutex until |
| * we've incremented swapped, because shmem_unuse_inode() will |
| * prune a !swapped inode from the swaplist under this mutex. |
| */ |
| mutex_lock(&shmem_swaplist_mutex); |
| if (list_empty(&info->swaplist)) |
| list_add_tail(&info->swaplist, &shmem_swaplist); |
| |
| if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
| spin_lock_irq(&info->lock); |
| shmem_recalc_inode(inode); |
| info->swapped++; |
| spin_unlock_irq(&info->lock); |
| |
| swap_shmem_alloc(swap); |
| shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
| |
| mutex_unlock(&shmem_swaplist_mutex); |
| BUG_ON(page_mapped(page)); |
| swap_writepage(page, wbc); |
| return 0; |
| } |
| |
| mutex_unlock(&shmem_swaplist_mutex); |
| free_swap: |
| swapcache_free(swap); |
| redirty: |
| set_page_dirty(page); |
| if (wbc->for_reclaim) |
| return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ |
| unlock_page(page); |
| return 0; |
| } |
| |
| #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS) |
| static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
| { |
| char buffer[64]; |
| |
| if (!mpol || mpol->mode == MPOL_DEFAULT) |
| return; /* show nothing */ |
| |
| mpol_to_str(buffer, sizeof(buffer), mpol); |
| |
| seq_printf(seq, ",mpol=%s", buffer); |
| } |
| |
| static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) |
| { |
| struct mempolicy *mpol = NULL; |
| if (sbinfo->mpol) { |
| spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ |
| mpol = sbinfo->mpol; |
| mpol_get(mpol); |
| spin_unlock(&sbinfo->stat_lock); |
| } |
| return mpol; |
| } |
| #else /* !CONFIG_NUMA || !CONFIG_TMPFS */ |
| static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
| { |
| } |
| static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) |
| { |
| return NULL; |
| } |
| #endif /* CONFIG_NUMA && CONFIG_TMPFS */ |
| #ifndef CONFIG_NUMA |
| #define vm_policy vm_private_data |
| #endif |
| |
| static void shmem_pseudo_vma_init(struct vm_area_struct *vma, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| /* Create a pseudo vma that just contains the policy */ |
| vma->vm_start = 0; |
| /* Bias interleave by inode number to distribute better across nodes */ |
| vma->vm_pgoff = index + info->vfs_inode.i_ino; |
| vma->vm_ops = NULL; |
| vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
| } |
| |
| static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma) |
| { |
| /* Drop reference taken by mpol_shared_policy_lookup() */ |
| mpol_cond_put(vma->vm_policy); |
| } |
| |
| static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct vm_area_struct pvma; |
| struct page *page; |
| |
| shmem_pseudo_vma_init(&pvma, info, index); |
| page = swapin_readahead(swap, gfp, &pvma, 0); |
| shmem_pseudo_vma_destroy(&pvma); |
| |
| return page; |
| } |
| |
| static struct page *shmem_alloc_hugepage(gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct vm_area_struct pvma; |
| struct inode *inode = &info->vfs_inode; |
| struct address_space *mapping = inode->i_mapping; |
| pgoff_t idx, hindex; |
| void __rcu **results; |
| struct page *page; |
| |
| if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
| return NULL; |
| |
| hindex = round_down(index, HPAGE_PMD_NR); |
| rcu_read_lock(); |
| if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx, |
| hindex, 1) && idx < hindex + HPAGE_PMD_NR) { |
| rcu_read_unlock(); |
| return NULL; |
| } |
| rcu_read_unlock(); |
| |
| shmem_pseudo_vma_init(&pvma, info, hindex); |
| page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN, |
| HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true); |
| shmem_pseudo_vma_destroy(&pvma); |
| if (page) |
| prep_transhuge_page(page); |
| return page; |
| } |
| |
| static struct page *shmem_alloc_page(gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct vm_area_struct pvma; |
| struct page *page; |
| |
| shmem_pseudo_vma_init(&pvma, info, index); |
| page = alloc_page_vma(gfp, &pvma, 0); |
| shmem_pseudo_vma_destroy(&pvma); |
| |
| return page; |
| } |
| |
| static struct page *shmem_alloc_and_acct_page(gfp_t gfp, |
| struct shmem_inode_info *info, struct shmem_sb_info *sbinfo, |
| pgoff_t index, bool huge) |
| { |
| struct page *page; |
| int nr; |
| int err = -ENOSPC; |
| |
| if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
| huge = false; |
| nr = huge ? HPAGE_PMD_NR : 1; |
| |
| if (shmem_acct_block(info->flags, nr)) |
| goto failed; |
| if (sbinfo->max_blocks) { |
| if (percpu_counter_compare(&sbinfo->used_blocks, |
| sbinfo->max_blocks - nr) > 0) |
| goto unacct; |
| percpu_counter_add(&sbinfo->used_blocks, nr); |
| } |
| |
| if (huge) |
| page = shmem_alloc_hugepage(gfp, info, index); |
| else |
| page = shmem_alloc_page(gfp, info, index); |
| if (page) { |
| __SetPageLocked(page); |
| __SetPageSwapBacked(page); |
| return page; |
| } |
| |
| err = -ENOMEM; |
| if (sbinfo->max_blocks) |
| percpu_counter_add(&sbinfo->used_blocks, -nr); |
| unacct: |
| shmem_unacct_blocks(info->flags, nr); |
| failed: |
| return ERR_PTR(err); |
| } |
| |
| /* |
| * When a page is moved from swapcache to shmem filecache (either by the |
| * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of |
| * shmem_unuse_inode()), it may have been read in earlier from swap, in |
| * ignorance of the mapping it belongs to. If that mapping has special |
| * constraints (like the gma500 GEM driver, which requires RAM below 4GB), |
| * we may need to copy to a suitable page before moving to filecache. |
| * |
| * In a future release, this may well be extended to respect cpuset and |
| * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); |
| * but for now it is a simple matter of zone. |
| */ |
| static bool shmem_should_replace_page(struct page *page, gfp_t gfp) |
| { |
| return page_zonenum(page) > gfp_zone(gfp); |
| } |
| |
| static int shmem_replace_page(struct page **pagep, gfp_t gfp, |
| struct shmem_inode_info *info, pgoff_t index) |
| { |
| struct page *oldpage, *newpage; |
| struct address_space *swap_mapping; |
| pgoff_t swap_index; |
| int error; |
| |
| oldpage = *pagep; |
| swap_index = page_private(oldpage); |
| swap_mapping = page_mapping(oldpage); |
| |
| /* |
| * We have arrived here because our zones are constrained, so don't |
| * limit chance of success by further cpuset and node constraints. |
| */ |
| gfp &= ~GFP_CONSTRAINT_MASK; |
| newpage = shmem_alloc_page(gfp, info, index); |
| if (!newpage) |
| return -ENOMEM; |
| |
| get_page(newpage); |
| copy_highpage(newpage, oldpage); |
| flush_dcache_page(newpage); |
| |
| __SetPageLocked(newpage); |
| __SetPageSwapBacked(newpage); |
| SetPageUptodate(newpage); |
| set_page_private(newpage, swap_index); |
| SetPageSwapCache(newpage); |
| |
| /* |
| * Our caller will very soon move newpage out of swapcache, but it's |
| * a nice clean interface for us to replace oldpage by newpage there. |
| */ |
| spin_lock_irq(&swap_mapping->tree_lock); |
| error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, |
| newpage); |
| if (!error) { |
| __inc_node_page_state(newpage, NR_FILE_PAGES); |
| __dec_node_page_state(oldpage, NR_FILE_PAGES); |
| } |
| spin_unlock_irq(&swap_mapping->tree_lock); |
| |
| if (unlikely(error)) { |
| /* |
| * Is this possible? I think not, now that our callers check |
| * both PageSwapCache and page_private after getting page lock; |
| * but be defensive. Reverse old to newpage for clear and free. |
| */ |
| oldpage = newpage; |
| } else { |
| mem_cgroup_migrate(oldpage, newpage); |
| lru_cache_add_anon(newpage); |
| *pagep = newpage; |
| } |
| |
| ClearPageSwapCache(oldpage); |
| set_page_private(oldpage, 0); |
| |
| unlock_page(oldpage); |
| put_page(oldpage); |
| put_page(oldpage); |
| return error; |
| } |
| |
| /* |
| * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
| * |
| * If we allocate a new one we do not mark it dirty. That's up to the |
| * vm. If we swap it in we mark it dirty since we also free the swap |
| * entry since a page cannot live in both the swap and page cache. |
| * |
| * fault_mm and fault_type are only supplied by shmem_fault: |
| * otherwise they are NULL. |
| */ |
| static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
| struct page **pagep, enum sgp_type sgp, gfp_t gfp, |
| struct vm_area_struct *vma, struct vm_fault *vmf, int *fault_type) |
| { |
| struct address_space *mapping = inode->i_mapping; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo; |
| struct mm_struct *charge_mm; |
| struct mem_cgroup *memcg; |
| struct page *page; |
| swp_entry_t swap; |
| enum sgp_type sgp_huge = sgp; |
| pgoff_t hindex = index; |
| int error; |
| int once = 0; |
| int alloced = 0; |
| |
| if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) |
| return -EFBIG; |
| if (sgp == SGP_NOHUGE || sgp == SGP_HUGE) |
| sgp = SGP_CACHE; |
| repeat: |
| swap.val = 0; |
| page = find_lock_entry(mapping, index); |
| if (radix_tree_exceptional_entry(page)) { |
| swap = radix_to_swp_entry(page); |
| page = NULL; |
| } |
| |
| if (sgp <= SGP_CACHE && |
| ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { |
| error = -EINVAL; |
| goto unlock; |
| } |
| |
| if (page && sgp == SGP_WRITE) |
| mark_page_accessed(page); |
| |
| /* fallocated page? */ |
| if (page && !PageUptodate(page)) { |
| if (sgp != SGP_READ) |
| goto clear; |
| unlock_page(page); |
| put_page(page); |
| page = NULL; |
| } |
| if (page || (sgp == SGP_READ && !swap.val)) { |
| *pagep = page; |
| return 0; |
| } |
| |
| /* |
| * Fast cache lookup did not find it: |
| * bring it back from swap or allocate. |
| */ |
| sbinfo = SHMEM_SB(inode->i_sb); |
| charge_mm = vma ? vma->vm_mm : current->mm; |
| |
| if (swap.val) { |
| /* Look it up and read it in.. */ |
| page = lookup_swap_cache(swap); |
| if (!page) { |
| /* Or update major stats only when swapin succeeds?? */ |
| if (fault_type) { |
| *fault_type |= VM_FAULT_MAJOR; |
| count_vm_event(PGMAJFAULT); |
| mem_cgroup_count_vm_event(charge_mm, |
| PGMAJFAULT); |
| } |
| /* Here we actually start the io */ |
| page = shmem_swapin(swap, gfp, info, index); |
| if (!page) { |
| error = -ENOMEM; |
| goto failed; |
| } |
| } |
| |
| /* We have to do this with page locked to prevent races */ |
| lock_page(page); |
| if (!PageSwapCache(page) || page_private(page) != swap.val || |
| !shmem_confirm_swap(mapping, index, swap)) { |
| error = -EEXIST; /* try again */ |
| goto unlock; |
| } |
| if (!PageUptodate(page)) { |
| error = -EIO; |
| goto failed; |
| } |
| wait_on_page_writeback(page); |
| |
| if (shmem_should_replace_page(page, gfp)) { |
| error = shmem_replace_page(&page, gfp, info, index); |
| if (error) |
| goto failed; |
| } |
| |
| error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, |
| false); |
| if (!error) { |
| error = shmem_add_to_page_cache(page, mapping, index, |
| swp_to_radix_entry(swap)); |
| /* |
| * We already confirmed swap under page lock, and make |
| * no memory allocation here, so usually no possibility |
| * of error; but free_swap_and_cache() only trylocks a |
| * page, so it is just possible that the entry has been |
| * truncated or holepunched since swap was confirmed. |
| * shmem_undo_range() will have done some of the |
| * unaccounting, now delete_from_swap_cache() will do |
| * the rest. |
| * Reset swap.val? No, leave it so "failed" goes back to |
| * "repeat": reading a hole and writing should succeed. |
| */ |
| if (error) { |
| mem_cgroup_cancel_charge(page, memcg, false); |
| delete_from_swap_cache(page); |
| } |
| } |
| if (error) |
| goto failed; |
| |
| mem_cgroup_commit_charge(page, memcg, true, false); |
| |
| spin_lock_irq(&info->lock); |
| info->swapped--; |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| |
| if (sgp == SGP_WRITE) |
| mark_page_accessed(page); |
| |
| delete_from_swap_cache(page); |
| set_page_dirty(page); |
| swap_free(swap); |
| |
| } else { |
| if (vma && userfaultfd_missing(vma)) { |
| *fault_type = handle_userfault(vmf, VM_UFFD_MISSING); |
| return 0; |
| } |
| |
| /* shmem_symlink() */ |
| if (mapping->a_ops != &shmem_aops) |
| goto alloc_nohuge; |
| if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) |
| goto alloc_nohuge; |
| if (shmem_huge == SHMEM_HUGE_FORCE) |
| goto alloc_huge; |
| switch (sbinfo->huge) { |
| loff_t i_size; |
| pgoff_t off; |
| case SHMEM_HUGE_NEVER: |
| goto alloc_nohuge; |
| case SHMEM_HUGE_WITHIN_SIZE: |
| off = round_up(index, HPAGE_PMD_NR); |
| i_size = round_up(i_size_read(inode), PAGE_SIZE); |
| if (i_size >= HPAGE_PMD_SIZE && |
| i_size >> PAGE_SHIFT >= off) |
| goto alloc_huge; |
| /* fallthrough */ |
| case SHMEM_HUGE_ADVISE: |
| if (sgp_huge == SGP_HUGE) |
| goto alloc_huge; |
| /* TODO: implement fadvise() hints */ |
| goto alloc_nohuge; |
| } |
| |
| alloc_huge: |
| page = shmem_alloc_and_acct_page(gfp, info, sbinfo, |
| index, true); |
| if (IS_ERR(page)) { |
| alloc_nohuge: page = shmem_alloc_and_acct_page(gfp, info, sbinfo, |
| index, false); |
| } |
| if (IS_ERR(page)) { |
| int retry = 5; |
| error = PTR_ERR(page); |
| page = NULL; |
| if (error != -ENOSPC) |
| goto failed; |
| /* |
| * Try to reclaim some spece by splitting a huge page |
| * beyond i_size on the filesystem. |
| */ |
| while (retry--) { |
| int ret; |
| ret = shmem_unused_huge_shrink(sbinfo, NULL, 1); |
| if (ret == SHRINK_STOP) |
| break; |
| if (ret) |
| goto alloc_nohuge; |
| } |
| goto failed; |
| } |
| |
| if (PageTransHuge(page)) |
| hindex = round_down(index, HPAGE_PMD_NR); |
| else |
| hindex = index; |
| |
| if (sgp == SGP_WRITE) |
| __SetPageReferenced(page); |
| |
| error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, |
| PageTransHuge(page)); |
| if (error) |
| goto unacct; |
| error = radix_tree_maybe_preload_order(gfp & GFP_RECLAIM_MASK, |
| compound_order(page)); |
| if (!error) { |
| error = shmem_add_to_page_cache(page, mapping, hindex, |
| NULL); |
| radix_tree_preload_end(); |
| } |
| if (error) { |
| mem_cgroup_cancel_charge(page, memcg, |
| PageTransHuge(page)); |
| goto unacct; |
| } |
| mem_cgroup_commit_charge(page, memcg, false, |
| PageTransHuge(page)); |
| lru_cache_add_anon(page); |
| |
| spin_lock_irq(&info->lock); |
| info->alloced += 1 << compound_order(page); |
| inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page); |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| alloced = true; |
| |
| if (PageTransHuge(page) && |
| DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < |
| hindex + HPAGE_PMD_NR - 1) { |
| /* |
| * Part of the huge page is beyond i_size: subject |
| * to shrink under memory pressure. |
| */ |
| spin_lock(&sbinfo->shrinklist_lock); |
| if (list_empty(&info->shrinklist)) { |
| list_add_tail(&info->shrinklist, |
| &sbinfo->shrinklist); |
| sbinfo->shrinklist_len++; |
| } |
| spin_unlock(&sbinfo->shrinklist_lock); |
| } |
| |
| /* |
| * Let SGP_FALLOC use the SGP_WRITE optimization on a new page. |
| */ |
| if (sgp == SGP_FALLOC) |
| sgp = SGP_WRITE; |
| clear: |
| /* |
| * Let SGP_WRITE caller clear ends if write does not fill page; |
| * but SGP_FALLOC on a page fallocated earlier must initialize |
| * it now, lest undo on failure cancel our earlier guarantee. |
| */ |
| if (sgp != SGP_WRITE && !PageUptodate(page)) { |
| struct page *head = compound_head(page); |
| int i; |
| |
| for (i = 0; i < (1 << compound_order(head)); i++) { |
| clear_highpage(head + i); |
| flush_dcache_page(head + i); |
| } |
| SetPageUptodate(head); |
| } |
| } |
| |
| /* Perhaps the file has been truncated since we checked */ |
| if (sgp <= SGP_CACHE && |
| ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { |
| if (alloced) { |
| ClearPageDirty(page); |
| delete_from_page_cache(page); |
| spin_lock_irq(&info->lock); |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| } |
| error = -EINVAL; |
| goto unlock; |
| } |
| *pagep = page + index - hindex; |
| return 0; |
| |
| /* |
| * Error recovery. |
| */ |
| unacct: |
| if (sbinfo->max_blocks) |
| percpu_counter_sub(&sbinfo->used_blocks, |
| 1 << compound_order(page)); |
| shmem_unacct_blocks(info->flags, 1 << compound_order(page)); |
| |
| if (PageTransHuge(page)) { |
| unlock_page(page); |
| put_page(page); |
| goto alloc_nohuge; |
| } |
| failed: |
| if (swap.val && !shmem_confirm_swap(mapping, index, swap)) |
| error = -EEXIST; |
| unlock: |
| if (page) { |
| unlock_page(page); |
| put_page(page); |
| } |
| if (error == -ENOSPC && !once++) { |
| spin_lock_irq(&info->lock); |
| shmem_recalc_inode(inode); |
| spin_unlock_irq(&info->lock); |
| goto repeat; |
| } |
| if (error == -EEXIST) /* from above or from radix_tree_insert */ |
| goto repeat; |
| return error; |
| } |
| |
| /* |
| * This is like autoremove_wake_function, but it removes the wait queue |
| * entry unconditionally - even if something else had already woken the |
| * target. |
| */ |
| static int synchronous_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key) |
| { |
| int ret = default_wake_function(wait, mode, sync, key); |
| list_del_init(&wait->task_list); |
| return ret; |
| } |
| |
| static int shmem_fault(struct vm_fault *vmf) |
| { |
| struct vm_area_struct *vma = vmf->vma; |
| struct inode *inode = file_inode(vma->vm_file); |
| gfp_t gfp = mapping_gfp_mask(inode->i_mapping); |
| enum sgp_type sgp; |
| int error; |
| int ret = VM_FAULT_LOCKED; |
| |
| /* |
| * Trinity finds that probing a hole which tmpfs is punching can |
| * prevent the hole-punch from ever completing: which in turn |
| * locks writers out with its hold on i_mutex. So refrain from |
| * faulting pages into the hole while it's being punched. Although |
| * shmem_undo_range() does remove the additions, it may be unable to |
| * keep up, as each new page needs its own unmap_mapping_range() call, |
| * and the i_mmap tree grows ever slower to scan if new vmas are added. |
| * |
| * It does not matter if we sometimes reach this check just before the |
| * hole-punch begins, so that one fault then races with the punch: |
| * we just need to make racing faults a rare case. |
| * |
| * The implementation below would be much simpler if we just used a |
| * standard mutex or completion: but we cannot take i_mutex in fault, |
| * and bloating every shmem inode for this unlikely case would be sad. |
| */ |
| if (unlikely(inode->i_private)) { |
| struct shmem_falloc *shmem_falloc; |
| |
| spin_lock(&inode->i_lock); |
| shmem_falloc = inode->i_private; |
| if (shmem_falloc && |
| shmem_falloc->waitq && |
| vmf->pgoff >= shmem_falloc->start && |
| vmf->pgoff < shmem_falloc->next) { |
| wait_queue_head_t *shmem_falloc_waitq; |
| DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); |
| |
| ret = VM_FAULT_NOPAGE; |
| if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && |
| !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { |
| /* It's polite to up mmap_sem if we can */ |
| up_read(&vma->vm_mm->mmap_sem); |
| ret = VM_FAULT_RETRY; |
| } |
| |
| shmem_falloc_waitq = shmem_falloc->waitq; |
| prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, |
| TASK_UNINTERRUPTIBLE); |
| spin_unlock(&inode->i_lock); |
| schedule(); |
| |
| /* |
| * shmem_falloc_waitq points into the shmem_fallocate() |
| * stack of the hole-punching task: shmem_falloc_waitq |
| * is usually invalid by the time we reach here, but |
| * finish_wait() does not dereference it in that case; |
| * though i_lock needed lest racing with wake_up_all(). |
| */ |
| spin_lock(&inode->i_lock); |
| finish_wait(shmem_falloc_waitq, &shmem_fault_wait); |
| spin_unlock(&inode->i_lock); |
| return ret; |
| } |
| spin_unlock(&inode->i_lock); |
| } |
| |
| sgp = SGP_CACHE; |
| if (vma->vm_flags & VM_HUGEPAGE) |
| sgp = SGP_HUGE; |
| else if (vma->vm_flags & VM_NOHUGEPAGE) |
| sgp = SGP_NOHUGE; |
| |
| error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp, |
| gfp, vma, vmf, &ret); |
| if (error) |
| return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); |
| return ret; |
| } |
| |
| unsigned long shmem_get_unmapped_area(struct file *file, |
| unsigned long uaddr, unsigned long len, |
| unsigned long pgoff, unsigned long flags) |
| { |
| unsigned long (*get_area)(struct file *, |
| unsigned long, unsigned long, unsigned long, unsigned long); |
| unsigned long addr; |
| unsigned long offset; |
| unsigned long inflated_len; |
| unsigned long inflated_addr; |
| unsigned long inflated_offset; |
| |
| if (len > TASK_SIZE) |
| return -ENOMEM; |
| |
| get_area = current->mm->get_unmapped_area; |
| addr = get_area(file, uaddr, len, pgoff, flags); |
| |
| if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
| return addr; |
| if (IS_ERR_VALUE(addr)) |
| return addr; |
| if (addr & ~PAGE_MASK) |
| return addr; |
| if (addr > TASK_SIZE - len) |
| return addr; |
| |
| if (shmem_huge == SHMEM_HUGE_DENY) |
| return addr; |
| if (len < HPAGE_PMD_SIZE) |
| return addr; |
| if (flags & MAP_FIXED) |
| return addr; |
| /* |
| * Our priority is to support MAP_SHARED mapped hugely; |
| * and support MAP_PRIVATE mapped hugely too, until it is COWed. |
| * But if caller specified an address hint, respect that as before. |
| */ |
| if (uaddr) |
| return addr; |
| |
| if (shmem_huge != SHMEM_HUGE_FORCE) { |
| struct super_block *sb; |
| |
| if (file) { |
| VM_BUG_ON(file->f_op != &shmem_file_operations); |
| sb = file_inode(file)->i_sb; |
| } else { |
| /* |
| * Called directly from mm/mmap.c, or drivers/char/mem.c |
| * for "/dev/zero", to create a shared anonymous object. |
| */ |
| if (IS_ERR(shm_mnt)) |
| return addr; |
| sb = shm_mnt->mnt_sb; |
| } |
| if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER) |
| return addr; |
| } |
| |
| offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1); |
| if (offset && offset + len < 2 * HPAGE_PMD_SIZE) |
| return addr; |
| if ((addr & (HPAGE_PMD_SIZE-1)) == offset) |
| return addr; |
| |
| inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE; |
| if (inflated_len > TASK_SIZE) |
| return addr; |
| if (inflated_len < len) |
| return addr; |
| |
| inflated_addr = get_area(NULL, 0, inflated_len, 0, flags); |
| if (IS_ERR_VALUE(inflated_addr)) |
| return addr; |
| if (inflated_addr & ~PAGE_MASK) |
| return addr; |
| |
| inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); |
| inflated_addr += offset - inflated_offset; |
| if (inflated_offset > offset) |
| inflated_addr += HPAGE_PMD_SIZE; |
| |
| if (inflated_addr > TASK_SIZE - len) |
| return addr; |
| return inflated_addr; |
| } |
| |
| #ifdef CONFIG_NUMA |
| static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
| { |
| struct inode *inode = file_inode(vma->vm_file); |
| return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); |
| } |
| |
| static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
| unsigned long addr) |
| { |
| struct inode *inode = file_inode(vma->vm_file); |
| pgoff_t index; |
| |
| index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
| return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); |
| } |
| #endif |
| |
| int shmem_lock(struct file *file, int lock, struct user_struct *user) |
| { |
| struct inode *inode = file_inode(file); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| int retval = -ENOMEM; |
| |
| spin_lock_irq(&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); |
| } |
| retval = 0; |
| |
| out_nomem: |
| spin_unlock_irq(&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; |
| if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && |
| ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < |
| (vma->vm_end & HPAGE_PMD_MASK)) { |
| khugepaged_enter(vma, vma->vm_flags); |
| } |
| return 0; |
| } |
| |
| static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
| umode_t mode, dev_t dev, unsigned long flags) |
| { |
| struct inode *inode; |
| struct shmem_inode_info *info; |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| |
| if (shmem_reserve_inode(sb)) |
| return NULL; |
| |
| inode = new_inode(sb); |
| if (inode) { |
| inode->i_ino = get_next_ino(); |
| inode_init_owner(inode, dir, mode); |
| inode->i_blocks = 0; |
| inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
| inode->i_generation = get_seconds(); |
| info = SHMEM_I(inode); |
| memset(info, 0, (char *)inode - (char *)info); |
| spin_lock_init(&info->lock); |
| info->seals = F_SEAL_SEAL; |
| info->flags = flags & VM_NORESERVE; |
| INIT_LIST_HEAD(&info->shrinklist); |
| INIT_LIST_HEAD(&info->swaplist); |
| simple_xattrs_init(&info->xattrs); |
| cache_no_acl(inode); |
| |
| switch (mode & S_IFMT) { |
| default: |
| inode->i_op = &shmem_special_inode_operations; |
| init_special_inode(inode, mode, dev); |
| break; |
| case S_IFREG: |
| inode->i_mapping->a_ops = &shmem_aops; |
| inode->i_op = &shmem_inode_operations; |
| inode->i_fop = &shmem_file_operations; |
| mpol_shared_policy_init(&info->policy, |
| shmem_get_sbmpol(sbinfo)); |
| break; |
| case S_IFDIR: |
| inc_nlink(inode); |
| /* Some things misbehave if size == 0 on a directory */ |
| inode->i_size = 2 * BOGO_DIRENT_SIZE; |
| inode->i_op = &shmem_dir_inode_operations; |
| inode->i_fop = &simple_dir_operations; |
| break; |
| case S_IFLNK: |
| /* |
| * Must not load anything in the rbtree, |
| * mpol_free_shared_policy will not be called. |
| */ |
| mpol_shared_policy_init(&info->policy, NULL); |
| break; |
| } |
| } else |
| shmem_free_inode(sb); |
| return inode; |
| } |
| |
| bool shmem_mapping(struct address_space *mapping) |
| { |
| return mapping->a_ops == &shmem_aops; |
| } |
| |
| int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, |
| pmd_t *dst_pmd, |
| struct vm_area_struct *dst_vma, |
| unsigned long dst_addr, |
| unsigned long src_addr, |
| struct page **pagep) |
| { |
| struct inode *inode = file_inode(dst_vma->vm_file); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| struct address_space *mapping = inode->i_mapping; |
| gfp_t gfp = mapping_gfp_mask(mapping); |
| pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); |
| struct mem_cgroup *memcg; |
| spinlock_t *ptl; |
| void *page_kaddr; |
| struct page *page; |
| pte_t _dst_pte, *dst_pte; |
| int ret; |
| |
| ret = -ENOMEM; |
| if (shmem_acct_block(info->flags, 1)) |
| goto out; |
| if (sbinfo->max_blocks) { |
| if (percpu_counter_compare(&sbinfo->used_blocks, |
| sbinfo->max_blocks) >= 0) |
| goto out_unacct_blocks; |
| percpu_counter_inc(&sbinfo->used_blocks); |
| } |
| |
| if (!*pagep) { |
| page = shmem_alloc_page(gfp, info, pgoff); |
| if (!page) |
| goto out_dec_used_blocks; |
| |
| page_kaddr = kmap_atomic(page); |
| ret = copy_from_user(page_kaddr, (const void __user *)src_addr, |
| PAGE_SIZE); |
| kunmap_atomic(page_kaddr); |
| |
| /* fallback to copy_from_user outside mmap_sem */ |
| if (unlikely(ret)) { |
| *pagep = page; |
| if (sbinfo->max_blocks) |
| percpu_counter_add(&sbinfo->used_blocks, -1); |
| shmem_unacct_blocks(info->flags, 1); |
| /* don't free the page */ |
| return -EFAULT; |
| } |
| } else { |
| page = *pagep; |
| *pagep = NULL; |
| } |
| |
| VM_BUG_ON(PageLocked(page) || PageSwapBacked(page)); |
| __SetPageLocked(page); |
| __SetPageSwapBacked(page); |
| __SetPageUptodate(page); |
| |
| ret = mem_cgroup_try_charge(page, dst_mm, gfp, &memcg, false); |
| if (ret) |
| goto out_release; |
| |
| ret = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK); |
| if (!ret) { |
| ret = shmem_add_to_page_cache(page, mapping, pgoff, NULL); |
| radix_tree_preload_end(); |
| } |
| if (ret) |
| goto out_release_uncharge; |
| |
| mem_cgroup_commit_charge(page, memcg, false, false); |
| |
| _dst_pte = mk_pte(page, dst_vma->vm_page_prot); |
| if (dst_vma->vm_flags & VM_WRITE) |
| _dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte)); |
| |
| ret = -EEXIST; |
| dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl); |
| if (!pte_none(*dst_pte)) |
| goto out_release_uncharge_unlock; |
| |
| lru_cache_add_anon(page); |
| |
| spin_lock(&info->lock); |
| info->alloced++; |
| inode->i_blocks += BLOCKS_PER_PAGE; |
| shmem_recalc_inode(inode); |
| spin_unlock(&info->lock); |
| |
| inc_mm_counter(dst_mm, mm_counter_file(page)); |
| page_add_file_rmap(page, false); |
| set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); |
| |
| /* No need to invalidate - it was non-present before */ |
| update_mmu_cache(dst_vma, dst_addr, dst_pte); |
| unlock_page(page); |
| pte_unmap_unlock(dst_pte, ptl); |
| ret = 0; |
| out: |
| return ret; |
| out_release_uncharge_unlock: |
| pte_unmap_unlock(dst_pte, ptl); |
| out_release_uncharge: |
| mem_cgroup_cancel_charge(page, memcg, false); |
| out_release: |
| unlock_page(page); |
| put_page(page); |
| out_dec_used_blocks: |
| if (sbinfo->max_blocks) |
| percpu_counter_add(&sbinfo->used_blocks, -1); |
| out_unacct_blocks: |
| shmem_unacct_blocks(info->flags, 1); |
| goto out; |
| } |
| |
| #ifdef CONFIG_TMPFS |
| static const struct inode_operations shmem_symlink_inode_operations; |
| static const struct inode_operations shmem_short_symlink_operations; |
| |
| #ifdef CONFIG_TMPFS_XATTR |
| static int shmem_initxattrs(struct inode *, const struct xattr *, void *); |
| #else |
| #define shmem_initxattrs NULL |
| #endif |
| |
| static int |
| shmem_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct inode *inode = mapping->host; |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| pgoff_t index = pos >> PAGE_SHIFT; |
| |
| /* i_mutex is held by caller */ |
| if (unlikely(info->seals & (F_SEAL_WRITE | F_SEAL_GROW))) { |
| if (info->seals & F_SEAL_WRITE) |
| return -EPERM; |
| if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size) |
| return -EPERM; |
| } |
| |
| return shmem_getpage(inode, index, pagep, SGP_WRITE); |
| } |
| |
| static int |
| shmem_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| |
| if (pos + copied > inode->i_size) |
| i_size_write(inode, pos + copied); |
| |
| if (!PageUptodate(page)) { |
| struct page *head = compound_head(page); |
| if (PageTransCompound(page)) { |
| int i; |
| |
| for (i = 0; i < HPAGE_PMD_NR; i++) { |
| if (head + i == page) |
| continue; |
| clear_highpage(head + i); |
| flush_dcache_page(head + i); |
| } |
| } |
| if (copied < PAGE_SIZE) { |
| unsigned from = pos & (PAGE_SIZE - 1); |
| zero_user_segments(page, 0, from, |
| from + copied, PAGE_SIZE); |
| } |
| SetPageUptodate(head); |
| } |
| set_page_dirty(page); |
| unlock_page(page); |
| put_page(page); |
| |
| return copied; |
| } |
| |
| static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
| { |
| struct file *file = iocb->ki_filp; |
| struct inode *inode = file_inode(file); |
| struct address_space *mapping = inode->i_mapping; |
| pgoff_t index; |
| unsigned long offset; |
| enum sgp_type sgp = SGP_READ; |
| int error = 0; |
| ssize_t retval = 0; |
| loff_t *ppos = &iocb->ki_pos; |
| |
| /* |
| * Might this read be for a stacking filesystem? Then when reading |
| * holes of a sparse file, we actually need to allocate those pages, |
| * and even mark them dirty, so it cannot exceed the max_blocks limit. |
| */ |
| if (!iter_is_iovec(to)) |
| sgp = SGP_CACHE; |
| |
| index = *ppos >> PAGE_SHIFT; |
| offset = *ppos & ~PAGE_MASK; |
| |
| for (;;) { |
| struct page *page = NULL; |
| pgoff_t end_index; |
| unsigned long nr, ret; |
| loff_t i_size = i_size_read(inode); |
| |
| end_index = i_size >> PAGE_SHIFT; |
| if (index > end_index) |
| break; |
| if (index == end_index) { |
| nr = i_size & ~PAGE_MASK; |
| if (nr <= offset) |
| break; |
| } |
| |
| error = shmem_getpage(inode, index, &page, sgp); |
| if (error) { |
| if (error == -EINVAL) |
| error = 0; |
| break; |
| } |
| if (page) { |
| if (sgp == SGP_CACHE) |
| set_page_dirty(page); |
| unlock_page(page); |
| } |
| |
| /* |
| * We must evaluate after, since reads (unlike writes) |
| * are called without i_mutex protection against truncate |
| */ |
| nr = PAGE_SIZE; |
| i_size = i_size_read(inode); |
| end_index = i_size >> PAGE_SHIFT; |
| if (index == end_index) { |
| nr = i_size & ~PAGE_MASK; |
| if (nr <= offset) { |
| if (page) |
| put_page(page); |
| break; |
| } |
| } |
| nr -= offset; |
| |
| if (page) { |
| /* |
| * If users can be writing to this page using arbitrary |
| * virtual addresses, take care about potential aliasing |
| * before reading the page on the kernel side. |
| */ |
| if (mapping_writably_mapped(mapping)) |
| flush_dcache_page(page); |
| /* |
| * Mark the page accessed if we read the beginning. |
| */ |
| if (!offset) |
| mark_page_accessed(page); |
| } else { |
| page = ZERO_PAGE(0); |
| get_page(page); |
| } |
| |
| /* |
| * Ok, we have the page, and it's up-to-date, so |
| * now we can copy it to user space... |
| */ |
| ret = copy_page_to_iter(page, offset, nr, to); |
| retval += ret; |
| offset += ret; |
| index += offset >> PAGE_SHIFT; |
| offset &= ~PAGE_MASK; |
| |
| put_page(page); |
| if (!iov_iter_count(to)) |
| break; |
| if (ret < nr) { |
| error = -EFAULT; |
| break; |
| } |
| cond_resched(); |
| } |
| |
| *ppos = ((loff_t) index << PAGE_SHIFT) + offset; |
| file_accessed(file); |
| return retval ? retval : error; |
| } |
| |
| /* |
| * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. |
| */ |
| static pgoff_t shmem_seek_hole_data(struct address_space *mapping, |
| pgoff_t index, pgoff_t end, int whence) |
| { |
| struct page *page; |
| struct pagevec pvec; |
| pgoff_t indices[PAGEVEC_SIZE]; |
| bool done = false; |
| int i; |
| |
| pagevec_init(&pvec, 0); |
| pvec.nr = 1; /* start small: we may be there already */ |
| while (!done) { |
| pvec.nr = find_get_entries(mapping, index, |
| pvec.nr, pvec.pages, indices); |
| if (!pvec.nr) { |
| if (whence == SEEK_DATA) |
| index = end; |
| break; |
| } |
| for (i = 0; i < pvec.nr; i++, index++) { |
| if (index < indices[i]) { |
| if (whence == SEEK_HOLE) { |
| done = true; |
| break; |
| } |
| index = indices[i]; |
| } |
| page = pvec.pages[i]; |
| if (page && !radix_tree_exceptional_entry(page)) { |
| if (!PageUptodate(page)) |
| page = NULL; |
| } |
| if (index >= end || |
| (page && whence == SEEK_DATA) || |
| (!page && whence == SEEK_HOLE)) { |
| done = true; |
| break; |
| } |
| } |
| pagevec_remove_exceptionals(&pvec); |
| pagevec_release(&pvec); |
| pvec.nr = PAGEVEC_SIZE; |
| cond_resched(); |
| } |
| return index; |
| } |
| |
| static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) |
| { |
| struct address_space *mapping = file->f_mapping; |
| struct inode *inode = mapping->host; |
| pgoff_t start, end; |
| loff_t new_offset; |
| |
| if (whence != SEEK_DATA && whence != SEEK_HOLE) |
| return generic_file_llseek_size(file, offset, whence, |
| MAX_LFS_FILESIZE, i_size_read(inode)); |
| inode_lock(inode); |
| /* We're holding i_mutex so we can access i_size directly */ |
| |
| if (offset < 0) |
| offset = -EINVAL; |
| else if (offset >= inode->i_size) |
| offset = -ENXIO; |
| else { |
| start = offset >> PAGE_SHIFT; |
| end = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| new_offset = shmem_seek_hole_data(mapping, start, end, whence); |
| new_offset <<= PAGE_SHIFT; |
| if (new_offset > offset) { |
| if (new_offset < inode->i_size) |
| offset = new_offset; |
| else if (whence == SEEK_DATA) |
| offset = -ENXIO; |
| else |
| offset = inode->i_size; |
| } |
| } |
| |
| if (offset >= 0) |
| offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); |
| inode_unlock(inode); |
| return offset; |
| } |
| |
| /* |
| * We need a tag: a new tag would expand every radix_tree_node by 8 bytes, |
| * so reuse a tag which we firmly believe is never set or cleared on shmem. |
| */ |
| #define SHMEM_TAG_PINNED PAGECACHE_TAG_TOWRITE |
| #define LAST_SCAN 4 /* about 150ms max */ |
| |
| static void shmem_tag_pins(struct address_space *mapping) |
| { |
| struct radix_tree_iter iter; |
| void **slot; |
| pgoff_t start; |
| struct page *page; |
| |
| lru_add_drain(); |
| start = 0; |
| rcu_read_lock(); |
| |
| radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { |
| page = radix_tree_deref_slot(slot); |
| if (!page || radix_tree_exception(page)) { |
| if (radix_tree_deref_retry(page)) { |
| slot = radix_tree_iter_retry(&iter); |
| continue; |
| } |
| } else if (page_count(page) - page_mapcount(page) > 1) { |
| spin_lock_irq(&mapping->tree_lock); |
| radix_tree_tag_set(&mapping->page_tree, iter.index, |
| SHMEM_TAG_PINNED); |
| spin_unlock_irq(&mapping->tree_lock); |
| } |
| |
| if (need_resched()) { |
| slot = radix_tree_iter_resume(slot, &iter); |
| cond_resched_rcu(); |
| } |
| } |
| rcu_read_unlock(); |
| } |
| |
| /* |
| * Setting SEAL_WRITE requires us to verify there's no pending writer. However, |
| * via get_user_pages(), drivers might have some pending I/O without any active |
| * user-space mappings (eg., direct-IO, AIO). Therefore, we look at all pages |
| * and see whether it has an elevated ref-count. If so, we tag them and wait for |
| * them to be dropped. |
| * The caller must guarantee that no new user will acquire writable references |
| * to those pages to avoid races. |
| */ |
| static int shmem_wait_for_pins(struct address_space *mapping) |
| { |
| struct radix_tree_iter iter; |
| void **slot; |
| pgoff_t start; |
| struct page *page; |
| int error, scan; |
| |
| shmem_tag_pins(mapping); |
| |
| error = 0; |
| for (scan = 0; scan <= LAST_SCAN; scan++) { |
| if (!radix_tree_tagged(&mapping->page_tree, SHMEM_TAG_PINNED)) |
| break; |
| |
| if (!scan) |
| lru_add_drain_all(); |
| else if (schedule_timeout_killable((HZ << scan) / 200)) |
| scan = LAST_SCAN; |
| |
| start = 0; |
| rcu_read_lock(); |
| radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, |
| start, SHMEM_TAG_PINNED) { |
| |
| page = radix_tree_deref_slot(slot); |
| if (radix_tree_exception(page)) { |
| if (radix_tree_deref_retry(page)) { |
| slot = radix_tree_iter_retry(&iter); |
| continue; |
| } |
| |
| page = NULL; |
| } |
| |
| if (page && |
| page_count(page) - page_mapcount(page) != 1) { |
| if (scan < LAST_SCAN) |
| goto continue_resched; |
| |
| /* |
| * On the last scan, we clean up all those tags |
| * we inserted; but make a note that we still |
| * found pages pinned. |
| */ |
| error = -EBUSY; |
| } |
| |
| spin_lock_irq(&mapping->tree_lock); |
| radix_tree_tag_clear(&mapping->page_tree, |
| iter.index, SHMEM_TAG_PINNED); |
| spin_unlock_irq(&mapping->tree_lock); |
| continue_resched: |
| if (need_resched()) { |
| slot = radix_tree_iter_resume(slot, &iter); |
| cond_resched_rcu(); |
| } |
| } |
| rcu_read_unlock(); |
| } |
| |
| return error; |
| } |
| |
| #define F_ALL_SEALS (F_SEAL_SEAL | \ |
| F_SEAL_SHRINK | \ |
| F_SEAL_GROW | \ |
| F_SEAL_WRITE) |
| |
| int shmem_add_seals(struct file *file, unsigned int seals) |
| { |
| struct inode *inode = file_inode(file); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| int error; |
| |
| /* |
| * SEALING |
| * Sealing allows multiple parties to share a shmem-file but restrict |
| * access to a specific subset of file operations. Seals can only be |
| * added, but never removed. This way, mutually untrusted parties can |
| * share common memory regions with a well-defined policy. A malicious |
| * peer can thus never perform unwanted operations on a shared object. |
| * |
| * Seals are only supported on special shmem-files and always affect |
| * the whole underlying inode. Once a seal is set, it may prevent some |
| * kinds of access to the file. Currently, the following seals are |
| * defined: |
| * SEAL_SEAL: Prevent further seals from being set on this file |
| * SEAL_SHRINK: Prevent the file from shrinking |
| * SEAL_GROW: Prevent the file from growing |
| * SEAL_WRITE: Prevent write access to the file |
| * |
| * As we don't require any trust relationship between two parties, we |
| * must prevent seals from being removed. Therefore, sealing a file |
| * only adds a given set of seals to the file, it never touches |
| * existing seals. Furthermore, the "setting seals"-operation can be |
| * sealed itself, which basically prevents any further seal from being |
| * added. |
| * |
| * Semantics of sealing are only defined on volatile files. Only |
| * anonymous shmem files support sealing. More importantly, seals are |
| * never written to disk. Therefore, there's no plan to support it on |
| * other file types. |
| */ |
| |
| if (file->f_op != &shmem_file_operations) |
| return -EINVAL; |
| if (!(file->f_mode & FMODE_WRITE)) |
| return -EPERM; |
| if (seals & ~(unsigned int)F_ALL_SEALS) |
| return -EINVAL; |
| |
| inode_lock(inode); |
| |
| if (info->seals & F_SEAL_SEAL) { |
| error = -EPERM; |
| goto unlock; |
| } |
| |
| if ((seals & F_SEAL_WRITE) && !(info->seals & F_SEAL_WRITE)) { |
| error = mapping_deny_writable(file->f_mapping); |
| if (error) |
| goto unlock; |
| |
| error = shmem_wait_for_pins(file->f_mapping); |
| if (error) { |
| mapping_allow_writable(file->f_mapping); |
| goto unlock; |
| } |
| } |
| |
| info->seals |= seals; |
| error = 0; |
| |
| unlock: |
| inode_unlock(inode); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(shmem_add_seals); |
| |
| int shmem_get_seals(struct file *file) |
| { |
| if (file->f_op != &shmem_file_operations) |
| return -EINVAL; |
| |
| return SHMEM_I(file_inode(file))->seals; |
| } |
| EXPORT_SYMBOL_GPL(shmem_get_seals); |
| |
| long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| long error; |
| |
| switch (cmd) { |
| case F_ADD_SEALS: |
| /* disallow upper 32bit */ |
| if (arg > UINT_MAX) |
| return -EINVAL; |
| |
| error = shmem_add_seals(file, arg); |
| break; |
| case F_GET_SEALS: |
| error = shmem_get_seals(file); |
| break; |
| default: |
| error = -EINVAL; |
| break; |
| } |
| |
| return error; |
| } |
| |
| static long shmem_fallocate(struct file *file, int mode, loff_t offset, |
| loff_t len) |
| { |
| struct inode *inode = file_inode(file); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| struct shmem_falloc shmem_falloc; |
| pgoff_t start, index, end; |
| int error; |
| |
| if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) |
| return -EOPNOTSUPP; |
| |
| inode_lock(inode); |
| |
| if (mode & FALLOC_FL_PUNCH_HOLE) { |
| struct address_space *mapping = file->f_mapping; |
| loff_t unmap_start = round_up(offset, PAGE_SIZE); |
| loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; |
| DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); |
| |
| /* protected by i_mutex */ |
| if (info->seals & F_SEAL_WRITE) { |
| error = -EPERM; |
| goto out; |
| } |
| |
| shmem_falloc.waitq = &shmem_falloc_waitq; |
| shmem_falloc.start = unmap_start >> PAGE_SHIFT; |
| shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; |
| spin_lock(&inode->i_lock); |
| inode->i_private = &shmem_falloc; |
| spin_unlock(&inode->i_lock); |
| |
| if ((u64)unmap_end > (u64)unmap_start) |
| unmap_mapping_range(mapping, unmap_start, |
| 1 + unmap_end - unmap_start, 0); |
| shmem_truncate_range(inode, offset, offset + len - 1); |
| /* No need to unmap again: hole-punching leaves COWed pages */ |
| |
| spin_lock(&inode->i_lock); |
| inode->i_private = NULL; |
| wake_up_all(&shmem_falloc_waitq); |
| WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.task_list)); |
| spin_unlock(&inode->i_lock); |
| error = 0; |
| goto out; |
| } |
| |
| /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ |
| error = inode_newsize_ok(inode, offset + len); |
| if (error) |
| goto out; |
| |
| if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { |
| error = -EPERM; |
| goto out; |
| } |
| |
| start = offset >> PAGE_SHIFT; |
| end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| /* Try to avoid a swapstorm if len is impossible to satisfy */ |
| if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { |
| error = -ENOSPC; |
| goto out; |
| } |
| |
| shmem_falloc.waitq = NULL; |
| shmem_falloc.start = start; |
| shmem_falloc.next = start; |
| shmem_falloc.nr_falloced = 0; |
| shmem_falloc.nr_unswapped = 0; |
| spin_lock(&inode->i_lock); |
| inode->i_private = &shmem_falloc; |
| spin_unlock(&inode->i_lock); |
| |
| for (index = start; index < end; index++) { |
| struct page *page; |
| |
| /* |
| * Good, the fallocate(2) manpage permits EINTR: we may have |
| * been interrupted because we are using up too much memory. |
| */ |
| if (signal_pending(current)) |
| error = -EINTR; |
| else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) |
| error = -ENOMEM; |
| else |
| error = shmem_getpage(inode, index, &page, SGP_FALLOC); |
| if (error) { |
| /* Remove the !PageUptodate pages we added */ |
| if (index > start) { |
| shmem_undo_range(inode, |
| (loff_t)start << PAGE_SHIFT, |
| ((loff_t)index << PAGE_SHIFT) - 1, true); |
| } |
| goto undone; |
| } |
| |
| /* |
| * Inform shmem_writepage() how far we have reached. |
| * No need for lock or barrier: we have the page lock. |
| */ |
| shmem_falloc.next++; |
| if (!PageUptodate(page)) |
| shmem_falloc.nr_falloced++; |
| |
| /* |
| * If !PageUptodate, leave it that way so that freeable pages |
| * can be recognized if we need to rollback on error later. |
| * But set_page_dirty so that memory pressure will swap rather |
| * than free the pages we are allocating (and SGP_CACHE pages |
| * might still be clean: we now need to mark those dirty too). |
| */ |
| set_page_dirty(page); |
| unlock_page(page); |
| put_page(page); |
| cond_resched(); |
| } |
| |
| if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) |
| i_size_write(inode, offset + len); |
| inode->i_ctime = current_time(inode); |
| undone: |
| spin_lock(&inode->i_lock); |
| inode->i_private = NULL; |
| spin_unlock(&inode->i_lock); |
| out: |
| inode_unlock(inode); |
| return error; |
| } |
| |
| static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
| |
| buf->f_type = TMPFS_MAGIC; |
| buf->f_bsize = PAGE_SIZE; |
| buf->f_namelen = NAME_MAX; |
| if (sbinfo->max_blocks) { |
| buf->f_blocks = sbinfo->max_blocks; |
| buf->f_bavail = |
| buf->f_bfree = sbinfo->max_blocks - |
| percpu_counter_sum(&sbinfo->used_blocks); |
| } |
| if (sbinfo->max_inodes) { |
| buf->f_files = sbinfo->max_inodes; |
| buf->f_ffree = sbinfo->free_inodes; |
| } |
| /* else leave those fields 0 like simple_statfs */ |
| return 0; |
| } |
| |
| /* |
| * File creation. Allocate an inode, and we're done.. |
| */ |
| static int |
| shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
| { |
| struct inode *inode; |
| int error = -ENOSPC; |
| |
| inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
| if (inode) { |
| error = simple_acl_create(dir, inode); |
| if (error) |
| goto out_iput; |
| error = security_inode_init_security(inode, dir, |
| &dentry->d_name, |
| shmem_initxattrs, NULL); |
| if (error && error != -EOPNOTSUPP) |
| goto out_iput; |
| |
| error = 0; |
| dir->i_size += BOGO_DIRENT_SIZE; |
| dir->i_ctime = dir->i_mtime = current_time(dir); |
| d_instantiate(dentry, inode); |
| dget(dentry); /* Extra count - pin the dentry in core */ |
| } |
| return error; |
| out_iput: |
| iput(inode); |
| return error; |
| } |
| |
| static int |
| shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) |
| { |
| struct inode *inode; |
| int error = -ENOSPC; |
| |
| inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE); |
| if (inode) { |
| error = security_inode_init_security(inode, dir, |
| NULL, |
| shmem_initxattrs, NULL); |
| if (error && error != -EOPNOTSUPP) |
| goto out_iput; |
| error = simple_acl_create(dir, inode); |
| if (error) |
| goto out_iput; |
| d_tmpfile(dentry, inode); |
| } |
| return error; |
| out_iput: |
| iput(inode); |
| return error; |
| } |
| |
| static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t 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, umode_t mode, |
| bool excl) |
| { |
| 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 = d_inode(old_dentry); |
| 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(inode); |
| inc_nlink(inode); |
| ihold(inode); /* New dentry reference */ |
| dget(dentry); /* Extra pinning count for the created dentry */ |
| d_instantiate(dentry, inode); |
| out: |
| return ret; |
| } |
| |
| static int shmem_unlink(struct inode *dir, struct dentry *dentry) |
| { |
| struct inode *inode = d_inode(dentry); |
| |
| if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
| shmem_free_inode(inode->i_sb); |
| |
| dir->i_size -= BOGO_DIRENT_SIZE; |
| inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
| drop_nlink(inode); |
| dput(dentry); /* Undo the count from "create" - this does all the work */ |
| return 0; |
| } |
| |
| static int shmem_rmdir(struct inode *dir, struct dentry *dentry) |
| { |
| if (!simple_empty(dentry)) |
| return -ENOTEMPTY; |
| |
| drop_nlink(d_inode(dentry)); |
| drop_nlink(dir); |
| return shmem_unlink(dir, dentry); |
| } |
| |
| static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) |
| { |
| bool old_is_dir = d_is_dir(old_dentry); |
| bool new_is_dir = d_is_dir(new_dentry); |
| |
| if (old_dir != new_dir && old_is_dir != new_is_dir) { |
| if (old_is_dir) { |
| drop_nlink(old_dir); |
| inc_nlink(new_dir); |
| } else { |
| drop_nlink(new_dir); |
| inc_nlink(old_dir); |
| } |
| } |
| old_dir->i_ctime = old_dir->i_mtime = |
| new_dir->i_ctime = new_dir->i_mtime = |
| d_inode(old_dentry)->i_ctime = |
| d_inode(new_dentry)->i_ctime = current_time(old_dir); |
| |
| return 0; |
| } |
| |
| static int shmem_whiteout(struct inode *old_dir, struct dentry *old_dentry) |
| { |
| struct dentry *whiteout; |
| int error; |
| |
| whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name); |
| if (!whiteout) |
| return -ENOMEM; |
| |
| error = shmem_mknod(old_dir, whiteout, |
| S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV); |
| dput(whiteout); |
| if (error) |
| return error; |
| |
| /* |
| * Cheat and hash the whiteout while the old dentry is still in |
| * place, instead of playing games with FS_RENAME_DOES_D_MOVE. |
| * |
| * d_lookup() will consistently find one of them at this point, |
| * not sure which one, but that isn't even important. |
| */ |
| d_rehash(whiteout); |
| return 0; |
| } |
| |
| /* |
| * The VFS layer already does all the dentry stuff for rename, |
| * we just have to decrement the usage count for the target if |
| * it exists so that the VFS layer correctly free's it when it |
| * gets overwritten. |
| */ |
| static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) |
| { |
| struct inode *inode = d_inode(old_dentry); |
| int they_are_dirs = S_ISDIR(inode->i_mode); |
| |
| if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) |
| return -EINVAL; |
| |
| if (flags & RENAME_EXCHANGE) |
| return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry); |
| |
| if (!simple_empty(new_dentry)) |
| return -ENOTEMPTY; |
| |
| if (flags & RENAME_WHITEOUT) { |
| int error; |
| |
| error = shmem_whiteout(old_dir, old_dentry); |
| if (error) |
| return error; |
| } |
| |
| if (d_really_is_positive(new_dentry)) { |
| (void) shmem_unlink(new_dir, new_dentry); |
| if (they_are_dirs) { |
| drop_nlink(d_inode(new_dentry)); |
| drop_nlink(old_dir); |
| } |
| } else if (they_are_dirs) { |
| drop_nlink(old_dir); |
| inc_nlink(new_dir); |
| } |
| |
| old_dir->i_size -= BOGO_DIRENT_SIZE; |
| new_dir->i_size += BOGO_DIRENT_SIZE; |
| old_dir->i_ctime = old_dir->i_mtime = |
| new_dir->i_ctime = new_dir->i_mtime = |
| inode->i_ctime = current_time(old_dir); |
| return 0; |
| } |
| |
| static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) |
| { |
| int error; |
| int len; |
| struct inode *inode; |
| struct page *page; |
| struct shmem_inode_info *info; |
| |
| len = strlen(symname) + 1; |
| if (len > PAGE_SIZE) |
| return -ENAMETOOLONG; |
| |
| inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
| if (!inode) |
| return -ENOSPC; |
| |
| error = security_inode_init_security(inode, dir, &dentry->d_name, |
| shmem_initxattrs, NULL); |
| if (error) { |
| if (error != -EOPNOTSUPP) { |
| iput(inode); |
| return error; |
| } |
| error = 0; |
| } |
| |
| info = SHMEM_I(inode); |
| inode->i_size = len-1; |
| if (len <= SHORT_SYMLINK_LEN) { |
| inode->i_link = kmemdup(symname, len, GFP_KERNEL); |
| if (!inode->i_link) { |
| iput(inode); |
| return -ENOMEM; |
| } |
| inode->i_op = &shmem_short_symlink_operations; |
| } else { |
| inode_nohighmem(inode); |
| error = shmem_getpage(inode, 0, &page, SGP_WRITE); |
| if (error) { |
| iput(inode); |
| return error; |
| } |
| inode->i_mapping->a_ops = &shmem_aops; |
| inode->i_op = &shmem_symlink_inode_operations; |
| memcpy(page_address(page), symname, len); |
| SetPageUptodate(page); |
| set_page_dirty(page); |
| unlock_page(page); |
| put_page(page); |
| } |
| dir->i_size += BOGO_DIRENT_SIZE; |
| dir->i_ctime = dir->i_mtime = current_time(dir); |
| d_instantiate(dentry, inode); |
| dget(dentry); |
| return 0; |
| } |
| |
| static void shmem_put_link(void *arg) |
| { |
| mark_page_accessed(arg); |
| put_page(arg); |
| } |
| |
| static const char *shmem_get_link(struct dentry *dentry, |
| struct inode *inode, |
| struct delayed_call *done) |
| { |
| struct page *page = NULL; |
| int error; |
| if (!dentry) { |
| page = find_get_page(inode->i_mapping, 0); |
| if (!page) |
| return ERR_PTR(-ECHILD); |
| if (!PageUptodate(page)) { |
| put_page(page); |
| return ERR_PTR(-ECHILD); |
| } |
| } else { |
| error = shmem_getpage(inode, 0, &page, SGP_READ); |
| if (error) |
| return ERR_PTR(error); |
| unlock_page(page); |
| } |
| set_delayed_call(done, shmem_put_link, page); |
| return page_address(page); |
| } |
| |
| #ifdef CONFIG_TMPFS_XATTR |
| /* |
| * Superblocks without xattr inode operations may get some security.* xattr |
| * support from the LSM "for free". As soon as we have any other xattrs |
| * like ACLs, we also need to implement the security.* handlers at |
| * filesystem level, though. |
| */ |
| |
| /* |
| * Callback for security_inode_init_security() for acquiring xattrs. |
| */ |
| static int shmem_initxattrs(struct inode *inode, |
| const struct xattr *xattr_array, |
| void *fs_info) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| const struct xattr *xattr; |
| struct simple_xattr *new_xattr; |
| size_t len; |
| |
| for (xattr = xattr_array; xattr->name != NULL; xattr++) { |
| new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); |
| if (!new_xattr) |
| return -ENOMEM; |
| |
| len = strlen(xattr->name) + 1; |
| new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, |
| GFP_KERNEL); |
| if (!new_xattr->name) { |
| kfree(new_xattr); |
| return -ENOMEM; |
| } |
| |
| memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, |
| XATTR_SECURITY_PREFIX_LEN); |
| memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, |
| xattr->name, len); |
| |
| simple_xattr_list_add(&info->xattrs, new_xattr); |
| } |
| |
| return 0; |
| } |
| |
| static int shmem_xattr_handler_get(const struct xattr_handler *handler, |
| struct dentry *unused, struct inode *inode, |
| const char *name, void *buffer, size_t size) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| |
| name = xattr_full_name(handler, name); |
| return simple_xattr_get(&info->xattrs, name, buffer, size); |
| } |
| |
| static int shmem_xattr_handler_set(const struct xattr_handler *handler, |
| struct dentry *unused, struct inode *inode, |
| const char *name, const void *value, |
| size_t size, int flags) |
| { |
| struct shmem_inode_info *info = SHMEM_I(inode); |
| |
| name = xattr_full_name(handler, name); |
| return simple_xattr_set(&info->xattrs, name, value, size, flags); |
| } |
| |
| static const struct xattr_handler shmem_security_xattr_handler = { |
| .prefix = XATTR_SECURITY_PREFIX, |
| .get = shmem_xattr_handler_get, |
| .set = shmem_xattr_handler_set, |
| }; |
| |
| static const struct xattr_handler shmem_trusted_xattr_handler = { |
| .prefix = XATTR_TRUSTED_PREFIX, |
| .get = shmem_xattr_handler_get, |
| .set = shmem_xattr_handler_set, |
| }; |
| |
| static const struct xattr_handler *shmem_xattr_handlers[] = { |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| &posix_acl_access_xattr_handler, |
| &posix_acl_default_xattr_handler, |
| #endif |
| &shmem_security_xattr_handler, |
| &shmem_trusted_xattr_handler, |
| NULL |
| }; |
| |
| static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| { |
| struct shmem_inode_info *info = SHMEM_I(d_inode(dentry)); |
| return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size); |
| } |
| #endif /* CONFIG_TMPFS_XATTR */ |
| |
| static const struct inode_operations shmem_short_symlink_operations = { |
| .get_link = simple_get_link, |
| #ifdef CONFIG_TMPFS_XATTR |
| .listxattr = shmem_listxattr, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_symlink_inode_operations = { |
| .get_link = shmem_get_link, |
| #ifdef CONFIG_TMPFS_XATTR |
| .listxattr = shmem_listxattr, |
| #endif |
| }; |
| |
| static struct dentry *shmem_get_parent(struct dentry *child) |
| { |
| return ERR_PTR(-ESTALE); |
| } |
| |
| static int shmem_match(struct inode *ino, void *vfh) |
| { |
| __u32 *fh = vfh; |
| __u64 inum = fh[2]; |
| inum = (inum << 32) | fh[1]; |
| return ino->i_ino == inum && fh[0] == ino->i_generation; |
| } |
| |
| static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
| struct fid *fid, int fh_len, int fh_type) |
| { |
| struct inode *inode; |
| struct dentry *dentry = NULL; |
| u64 inum; |
| |
| if (fh_len < 3) |
| return NULL; |
| |
| inum = fid->raw[2]; |
| inum = (inum << 32) | fid->raw[1]; |
| |
| inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
| shmem_match, fid->raw); |
| if (inode) { |
| dentry = d_find_alias(inode); |
| iput(inode); |
| } |
| |
| return dentry; |
| } |
| |
| static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, |
| struct inode *parent) |
| { |
| if (*len < 3) { |
| *len = 3; |
| return FILEID_INVALID; |
| } |
| |
| if (inode_unhashed(inode)) { |
| /* Unfortunately insert_inode_hash is not idempotent, |
| * so as we hash inodes here rather than at creation |
| * time, we need a lock to ensure we only try |
| * to do it once |
| */ |
| static DEFINE_SPINLOCK(lock); |
| spin_lock(&lock); |
| if (inode_unhashed(inode)) |
| __insert_inode_hash(inode, |
| inode->i_ino + inode->i_generation); |
| spin_unlock(&lock); |
| } |
| |
| fh[0] = inode->i_generation; |
| fh[1] = inode->i_ino; |
| fh[2] = ((__u64)inode->i_ino) >> 32; |
| |
| *len = 3; |
| return 1; |
| } |
| |
| static const struct export_operations shmem_export_ops = { |
| .get_parent = shmem_get_parent, |
| .encode_fh = shmem_encode_fh, |
| .fh_to_dentry = shmem_fh_to_dentry, |
| }; |
| |
| static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
| bool remount) |
| { |
| char *this_char, *value, *rest; |
| struct mempolicy *mpol = NULL; |
| uid_t uid; |
| gid_t gid; |
| |
| 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 { |
| pr_err("tmpfs: No value for mount option '%s'\n", |
| this_char); |
| goto error; |
| } |
| |
| 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_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; |
| uid = simple_strtoul(value, &rest, 0); |
| if (*rest) |
| goto bad_val; |
| sbinfo->uid = make_kuid(current_user_ns(), uid); |
| if (!uid_valid(sbinfo->uid)) |
| goto bad_val; |
| } else if (!strcmp(this_char,"gid")) { |
| if (remount) |
| continue; |
| gid = simple_strtoul(value, &rest, 0); |
| if (*rest) |
| goto bad_val; |
| sbinfo->gid = make_kgid(current_user_ns(), gid); |
| if (!gid_valid(sbinfo->gid)) |
| goto bad_val; |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| } else if (!strcmp(this_char, "huge")) { |
| int huge; |
| huge = shmem_parse_huge(value); |
| if (huge < 0) |
| goto bad_val; |
| if (!has_transparent_hugepage() && |
| huge != SHMEM_HUGE_NEVER) |
| goto bad_val; |
| sbinfo->huge = huge; |
| #endif |
| #ifdef CONFIG_NUMA |
| } else if (!strcmp(this_char,"mpol")) { |
| mpol_put(mpol); |
| mpol = NULL; |
| if (mpol_parse_str(value, &mpol)) |
| goto bad_val; |
| #endif |
| } else { |
| pr_err("tmpfs: Bad mount option %s\n", this_char); |
| goto error; |
| } |
| } |
| sbinfo->mpol = mpol; |
| return 0; |
| |
| bad_val: |
| pr_err("tmpfs: Bad value '%s' for mount option '%s'\n", |
| value, this_char); |
| error: |
| mpol_put(mpol); |
| 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 inodes; |
| int error = -EINVAL; |
| |
| config.mpol = NULL; |
| if (shmem_parse_options(data, &config, true)) |
| return error; |
| |
| spin_lock(&sbinfo->stat_lock); |
| inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
| if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
| goto out; |
| if (config.max_inodes < inodes) |
| goto out; |
| /* |
| * Those tests disallow limited->unlimited while any are in use; |
| * but we must separately disallow unlimited->limited, because |
| * in that case we have no record of how much is already in use. |
| */ |
| if (config.max_blocks && !sbinfo->max_blocks) |
| goto out; |
| if (config.max_inodes && !sbinfo->max_inodes) |
| goto out; |
| |
| error = 0; |
| sbinfo->huge = config.huge; |
| sbinfo->max_blocks = config.max_blocks; |
| sbinfo->max_inodes = config.max_inodes; |
| sbinfo->free_inodes = config.max_inodes - inodes; |
| |
| /* |
| * Preserve previous mempolicy unless mpol remount option was specified. |
| */ |
| if (config.mpol) { |
| 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 dentry *root) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
| |
| if (sbinfo->max_blocks != shmem_default_max_blocks()) |
| seq_printf(seq, ",size=%luk", |
| sbinfo->max_blocks << (PAGE_SHIFT - 10)); |
| if (sbinfo->max_inodes != shmem_default_max_inodes()) |
| seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); |
| if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) |
| seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
| if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) |
| seq_printf(seq, ",uid=%u", |
| from_kuid_munged(&init_user_ns, sbinfo->uid)); |
| if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) |
| seq_printf(seq, ",gid=%u", |
| from_kgid_munged(&init_user_ns, sbinfo->gid)); |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */ |
| if (sbinfo->huge) |
| seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge)); |
| #endif |
| shmem_show_mpol(seq, sbinfo->mpol); |
| return 0; |
| } |
| |
| #define MFD_NAME_PREFIX "memfd:" |
| #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) |
| #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) |
| |
| #define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING) |
| |
| SYSCALL_DEFINE2(memfd_create, |
| const char __user *, uname, |
| unsigned int, flags) |
| { |
| struct shmem_inode_info *info; |
| struct file *file; |
| int fd, error; |
| char *name; |
| long len; |
| |
| if (flags & ~(unsigned int)MFD_ALL_FLAGS) |
| return -EINVAL; |
| |
| /* length includes terminating zero */ |
| len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); |
| if (len <= 0) |
| return -EFAULT; |
| if (len > MFD_NAME_MAX_LEN + 1) |
| return -EINVAL; |
| |
| name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_TEMPORARY); |
| if (!name) |
| return -ENOMEM; |
| |
| strcpy(name, MFD_NAME_PREFIX); |
| if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) { |
| error = -EFAULT; |
| goto err_name; |
| } |
| |
| /* terminating-zero may have changed after strnlen_user() returned */ |
| if (name[len + MFD_NAME_PREFIX_LEN - 1]) { |
| error = -EFAULT; |
| goto err_name; |
| } |
| |
| fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0); |
| if (fd < 0) { |
| error = fd; |
| goto err_name; |
| } |
| |
| file = shmem_file_setup(name, 0, VM_NORESERVE); |
| if (IS_ERR(file)) { |
| error = PTR_ERR(file); |
| goto err_fd; |
| } |
| info = SHMEM_I(file_inode(file)); |
| file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; |
| file->f_flags |= O_RDWR | O_LARGEFILE; |
| if (flags & MFD_ALLOW_SEALING) |
| info->seals &= ~F_SEAL_SEAL; |
| |
| fd_install(fd, file); |
| kfree(name); |
| return fd; |
| |
| err_fd: |
| put_unused_fd(fd); |
| err_name: |
| kfree(name); |
| return error; |
| } |
| |
| #endif /* CONFIG_TMPFS */ |
| |
| static void shmem_put_super(struct super_block *sb) |
| { |
| struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
| |
| percpu_counter_destroy(&sbinfo->used_blocks); |
| mpol_put(sbinfo->mpol); |
| kfree(sbinfo); |
| sb->s_fs_info = NULL; |
| } |
| |
| int shmem_fill_super(struct super_block *sb, void *data, int silent) |
| { |
| struct inode *inode; |
| struct shmem_sb_info *sbinfo; |
| int err = -ENOMEM; |
| |
| /* Round up to L1_CACHE_BYTES to resist false sharing */ |
| sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
| L1_CACHE_BYTES), GFP_KERNEL); |
| if (!sbinfo) |
| return -ENOMEM; |
| |
| 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_KERNMOUNT)) { |
| 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; |
| } |
| } else { |
| sb->s_flags |= MS_NOUSER; |
| } |
| sb->s_export_op = &shmem_export_ops; |
| sb->s_flags |= MS_NOSEC; |
| #else |
| sb->s_flags |= MS_NOUSER; |
| #endif |
| |
| spin_lock_init(&sbinfo->stat_lock); |
| if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) |
| goto failed; |
| sbinfo->free_inodes = sbinfo->max_inodes; |
| spin_lock_init(&sbinfo->shrinklist_lock); |
| INIT_LIST_HEAD(&sbinfo->shrinklist); |
| |
| sb->s_maxbytes = MAX_LFS_FILESIZE; |
| sb->s_blocksize = PAGE_SIZE; |
| sb->s_blocksize_bits = PAGE_SHIFT; |
| sb->s_magic = TMPFS_MAGIC; |
| sb->s_op = &shmem_ops; |
| sb->s_time_gran = 1; |
| #ifdef CONFIG_TMPFS_XATTR |
| sb->s_xattr = shmem_xattr_handlers; |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| sb->s_flags |= MS_POSIXACL; |
| #endif |
| uuid_gen(&sb->s_uuid); |
| |
| inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
| if (!inode) |
| goto failed; |
| inode->i_uid = sbinfo->uid; |
| inode->i_gid = sbinfo->gid; |
| sb->s_root = d_make_root(inode); |
| if (!sb->s_root) |
| goto failed; |
| return 0; |
| |
| failed: |
| shmem_put_super(sb); |
| return err; |
| } |
| |
| static struct kmem_cache *shmem_inode_cachep; |
| |
| static struct inode *shmem_alloc_inode(struct super_block *sb) |
| { |
| struct shmem_inode_info *info; |
| info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
| if (!info) |
| return NULL; |
| return &info->vfs_inode; |
| } |
| |
| static void shmem_destroy_callback(struct rcu_head *head) |
| { |
| struct inode *inode = container_of(head, struct inode, i_rcu); |
| if (S_ISLNK(inode->i_mode)) |
| kfree(inode->i_link); |
| kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
| } |
| |
| static void shmem_destroy_inode(struct inode *inode) |
| { |
| if (S_ISREG(inode->i_mode)) |
| mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
| call_rcu(&inode->i_rcu, shmem_destroy_callback); |
| } |
| |
| static void shmem_init_inode(void *foo) |
| { |
| struct shmem_inode_info *info = foo; |
| inode_init_once(&info->vfs_inode); |
| } |
| |
| static int shmem_init_inodecache(void) |
| { |
| shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", |
| sizeof(struct shmem_inode_info), |
| 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); |
| return 0; |
| } |
| |
| static void shmem_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 |
| .write_begin = shmem_write_begin, |
| .write_end = shmem_write_end, |
| #endif |
| #ifdef CONFIG_MIGRATION |
| .migratepage = migrate_page, |
| #endif |
| .error_remove_page = generic_error_remove_page, |
| }; |
| |
| static const struct file_operations shmem_file_operations = { |
| .mmap = shmem_mmap, |
| .get_unmapped_area = shmem_get_unmapped_area, |
| #ifdef CONFIG_TMPFS |
| .llseek = shmem_file_llseek, |
| .read_iter = shmem_file_read_iter, |
| .write_iter = generic_file_write_iter, |
| .fsync = noop_fsync, |
| .splice_read = generic_file_splice_read, |
| .splice_write = iter_file_splice_write, |
| .fallocate = shmem_fallocate, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_inode_operations = { |
| .getattr = shmem_getattr, |
| .setattr = shmem_setattr, |
| #ifdef CONFIG_TMPFS_XATTR |
| .listxattr = shmem_listxattr, |
| .set_acl = simple_set_acl, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_dir_inode_operations = { |
| #ifdef CONFIG_TMPFS |
| .create = shmem_create, |
| .lookup = simple_lookup, |
| .link = shmem_link, |
| .unlink = shmem_unlink, |
| .symlink = shmem_symlink, |
| .mkdir = shmem_mkdir, |
| .rmdir = shmem_rmdir, |
| .mknod = shmem_mknod, |
| .rename = shmem_rename2, |
| .tmpfile = shmem_tmpfile, |
| #endif |
| #ifdef CONFIG_TMPFS_XATTR |
| .listxattr = shmem_listxattr, |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| .setattr = shmem_setattr, |
| .set_acl = simple_set_acl, |
| #endif |
| }; |
| |
| static const struct inode_operations shmem_special_inode_operations = { |
| #ifdef CONFIG_TMPFS_XATTR |
| .listxattr = shmem_listxattr, |
| #endif |
| #ifdef CONFIG_TMPFS_POSIX_ACL |
| .setattr = shmem_setattr, |
| .set_acl = simple_set_acl, |
| #endif |
| }; |
| |
| static const struct super_operations shmem_ops = { |
| .alloc_inode = shmem_alloc_inode, |
| .destroy_inode = shmem_destroy_inode, |
| #ifdef CONFIG_TMPFS |
| .statfs = shmem_statfs, |
| .remount_fs = shmem_remount_fs, |
| .show_options = shmem_show_options, |
| #endif |
| .evict_inode = shmem_evict_inode, |
| .drop_inode = generic_delete_inode, |
| .put_super = shmem_put_super, |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| .nr_cached_objects = shmem_unused_huge_count, |
| .free_cached_objects = shmem_unused_huge_scan, |
| #endif |
| }; |
| |
| static const struct vm_operations_struct shmem_vm_ops = { |
| .fault = shmem_fault, |
| .map_pages = filemap_map_pages, |
| #ifdef CONFIG_NUMA |
| .set_policy = shmem_set_policy, |
| .get_policy = shmem_get_policy, |
| #endif |
| }; |
| |
| static struct dentry *shmem_mount(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data) |
| { |
| return mount_nodev(fs_type, flags, data, shmem_fill_super); |
| } |
| |
| static struct file_system_type shmem_fs_type = { |
| .owner = THIS_MODULE, |
| .name = "tmpfs", |
| .mount = shmem_mount, |
| .kill_sb = kill_litter_super, |
| .fs_flags = FS_USERNS_MOUNT, |
| }; |
| |
| int __init shmem_init(void) |
| { |
| int error; |
| |
| /* If rootfs called this, don't re-init */ |
| if (shmem_inode_cachep) |
| return 0; |
| |
| error = shmem_init_inodecache(); |
| if (error) |
| goto out3; |
| |
| error = register_filesystem(&shmem_fs_type); |
| if (error) { |
| pr_err("Could not register tmpfs\n"); |
| goto out2; |
| } |
| |
| shm_mnt = kern_mount(&shmem_fs_type); |
| if (IS_ERR(shm_mnt)) { |
| error = PTR_ERR(shm_mnt); |
| pr_err("Could not kern_mount tmpfs\n"); |
| goto out1; |
| } |
| |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY) |
| SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; |
| else |
| shmem_huge = 0; /* just in case it was patched */ |
| #endif |
| return 0; |
| |
| out1: |
| unregister_filesystem(&shmem_fs_type); |
| out2: |
| shmem_destroy_inodecache(); |
| out3: |
| shm_mnt = ERR_PTR(error); |
| return error; |
| } |
| |
| #if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS) |
| static ssize_t shmem_enabled_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| int values[] = { |
| SHMEM_HUGE_ALWAYS, |
| SHMEM_HUGE_WITHIN_SIZE, |
| SHMEM_HUGE_ADVISE, |
| SHMEM_HUGE_NEVER, |
| SHMEM_HUGE_DENY, |
| SHMEM_HUGE_FORCE, |
| }; |
| int i, count; |
| |
| for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) { |
| const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s "; |
| |
| count += sprintf(buf + count, fmt, |
| shmem_format_huge(values[i])); |
| } |
| buf[count - 1] = '\n'; |
| return count; |
| } |
| |
| static ssize_t shmem_enabled_store(struct kobject *kobj, |
| struct kobj_attribute *attr, const char *buf, size_t count) |
| { |
| char tmp[16]; |
| int huge; |
| |
| if (count + 1 > sizeof(tmp)) |
| return -EINVAL; |
| memcpy(tmp, buf, count); |
| tmp[count] = '\0'; |
| if (count && tmp[count - 1] == '\n') |
| tmp[count - 1] = '\0'; |
| |
| huge = shmem_parse_huge(tmp); |
| if (huge == -EINVAL) |
| return -EINVAL; |
| if (!has_transparent_hugepage() && |
| huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) |
| return -EINVAL; |
| |
| shmem_huge = huge; |
| if (shmem_huge < SHMEM_HUGE_DENY) |
| SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; |
| return count; |
| } |
| |
| struct kobj_attribute shmem_enabled_attr = |
| __ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store); |
| #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */ |
| |
| #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
| bool shmem_huge_enabled(struct vm_area_struct *vma) |
| { |
| struct inode *inode = file_inode(vma->vm_file); |
| struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
| loff_t i_size; |
| pgoff_t off; |
| |
| if (shmem_huge == SHMEM_HUGE_FORCE) |
| return true; |
| if (shmem_huge == SHMEM_HUGE_DENY) |
| return false; |
| switch (sbinfo->huge) { |
| case SHMEM_HUGE_NEVER: |
| return false; |
| case SHMEM_HUGE_ALWAYS: |
| return true; |
| case SHMEM_HUGE_WITHIN_SIZE: |
| off = round_up(vma->vm_pgoff, HPAGE_PMD_NR); |
| i_size = round_up(i_size_read(inode), PAGE_SIZE); |
| if (i_size >= HPAGE_PMD_SIZE && |
| i_size >> PAGE_SHIFT >= off) |
| return true; |
| case SHMEM_HUGE_ADVISE: |
| /* TODO: implement fadvise() hints */ |
| return (vma->vm_flags & VM_HUGEPAGE); |
| default: |
| VM_BUG_ON(1); |
| return false; |
| } |
| } |
| #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
| |
| #else /* !CONFIG_SHMEM */ |
| |
| /* |
| * tiny-shmem: simple shmemfs and tmpfs using ramfs code |
| * |
| * This is intended for small system where the benefits of the full |
| * shmem code (swap-backed and resource-limited) are outweighed by |
| * their complexity. On systems without swap this code should be |
| * effectively equivalent, but much lighter weight. |
| */ |
| |
| static struct file_system_type shmem_fs_type = { |
| .name = "tmpfs", |
| .mount = ramfs_mount, |
| .kill_sb = kill_litter_super, |
| .fs_flags = FS_USERNS_MOUNT, |
| }; |
| |
| int __init shmem_init(void) |
| { |
| BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
| |
| shm_mnt = kern_mount(&shmem_fs_type); |
| BUG_ON(IS_ERR(shm_mnt)); |
| |
| return 0; |
| } |
| |
| int shmem_unuse(swp_entry_t swap, struct page *page) |
| { |
| return 0; |
| } |
| |
| int shmem_lock(struct file *file, int lock, struct user_struct *user) |
| { |
| return 0; |
| } |
| |
| void shmem_unlock_mapping(struct address_space *mapping) |
| { |
| } |
| |
| #ifdef CONFIG_MMU |
| unsigned long shmem_get_unmapped_area(struct file *file, |
| unsigned long addr, unsigned long len, |
| unsigned long pgoff, unsigned long flags) |
| { |
| return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); |
| } |
| #endif |
| |
| void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
| { |
| truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
| } |
| EXPORT_SYMBOL_GPL(shmem_truncate_range); |
| |
| #define shmem_vm_ops generic_file_vm_ops |
| #define shmem_file_operations ramfs_file_operations |
| #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
| #define shmem_acct_size(flags, size) 0 |
| #define shmem_unacct_size(flags, size) do {} while (0) |
| |
| #endif /* CONFIG_SHMEM */ |
| |
| /* common code */ |
| |
| static const struct dentry_operations anon_ops = { |
| .d_dname = simple_dname |
| }; |
| |
| static struct file *__shmem_file_setup(const char *name, loff_t size, |
| unsigned long flags, unsigned int i_flags) |
| { |
| struct file *res; |
| struct inode *inode; |
| struct path path; |
| struct super_block *sb; |
| struct qstr this; |
| |
| if (IS_ERR(shm_mnt)) |
| return ERR_CAST(shm_mnt); |
| |
| if (size < 0 || size > MAX_LFS_FILESIZE) |
| return ERR_PTR(-EINVAL); |
| |
| if (shmem_acct_size(flags, size)) |
| return ERR_PTR(-ENOMEM); |
| |
| res = ERR_PTR(-ENOMEM); |
| this.name = name; |
| this.len = strlen(name); |
| this.hash = 0; /* will go */ |
| sb = shm_mnt->mnt_sb; |
| path.mnt = mntget(shm_mnt); |
| path.dentry = d_alloc_pseudo(sb, &this); |
| if (!path.dentry) |
| goto put_memory; |
| d_set_d_op(path.dentry, &anon_ops); |
| |
| res = ERR_PTR(-ENOSPC); |
| inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
| if (!inode) |
| goto put_memory; |
| |
| inode->i_flags |= i_flags; |
| d_instantiate(path.dentry, inode); |
| inode->i_size = size; |
| clear_nlink(inode); /* It is unlinked */ |
| res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); |
| if (IS_ERR(res)) |
| goto put_path; |
| |
| res = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
| &shmem_file_operations); |
| if (IS_ERR(res)) |
| goto put_path; |
| |
| return res; |
| |
| put_memory: |
| shmem_unacct_size(flags, size); |
| put_path: |
| path_put(&path); |
| return res; |
| } |
| |
| /** |
| * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be |
| * kernel internal. There will be NO LSM permission checks against the |
| * underlying inode. So users of this interface must do LSM checks at a |
| * higher layer. The users are the big_key and shm implementations. LSM |
| * checks are provided at the key or shm level rather than the inode. |
| * @name: name for dentry (to be seen in /proc/<pid>/maps |
| * @size: size to be set for the file |
| * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
| */ |
| struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) |
| { |
| return __shmem_file_setup(name, size, flags, S_PRIVATE); |
| } |
| |
| /** |
| * shmem_file_setup - get an unlinked file living in tmpfs |
| * @name: name for dentry (to be seen in /proc/<pid>/maps |
| * @size: size to be set for the file |
| * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
| */ |
| struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
| { |
| return __shmem_file_setup(name, size, flags, 0); |
| } |
| 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; |
| |
| /* |
| * Cloning a new file under mmap_sem leads to a lock ordering conflict |
| * between XFS directory reading and selinux: since this file is only |
| * accessible to the user through its mapping, use S_PRIVATE flag to |
| * bypass file security, in the same way as shmem_kernel_file_setup(). |
| */ |
| file = __shmem_file_setup("dev/zero", size, vma->vm_flags, S_PRIVATE); |
| if (IS_ERR(file)) |
| return PTR_ERR(file); |
| |
| if (vma->vm_file) |
| fput(vma->vm_file); |
| vma->vm_file = file; |
| vma->vm_ops = &shmem_vm_ops; |
| |
| if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && |
| ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < |
| (vma->vm_end & HPAGE_PMD_MASK)) { |
| khugepaged_enter(vma, vma->vm_flags); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. |
| * @mapping: the page's address_space |
| * @index: the page index |
| * @gfp: the page allocator flags to use if allocating |
| * |
| * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", |
| * with any new page allocations done using the specified allocation flags. |
| * But read_cache_page_gfp() uses the ->readpage() method: which does not |
| * suit tmpfs, since it may have pages in swapcache, and needs to find those |
| * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. |
| * |
| * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
| * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. |
| */ |
| struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, |
| pgoff_t index, gfp_t gfp) |
| { |
| #ifdef CONFIG_SHMEM |
| struct inode *inode = mapping->host; |
| struct page *page; |
| int error; |
| |
| BUG_ON(mapping->a_ops != &shmem_aops); |
| error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, |
| gfp, NULL, NULL, NULL); |
| if (error) |
| page = ERR_PTR(error); |
| else |
| unlock_page(page); |
| return page; |
| #else |
| /* |
| * The tiny !SHMEM case uses ramfs without swap |
| */ |
| return read_cache_page_gfp(mapping, index, gfp); |
| #endif |
| } |
| EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |