| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Hugh Dickins | 5218 | 22.82% | 135 | 18.65% |
| Kirill A. Shutemov | 1672 | 7.31% | 15 | 2.07% |
| Matthew Wilcox | 1289 | 5.64% | 66 | 9.12% |
| Linus Torvalds | 1160 | 5.07% | 20 | 2.76% |
| Baolin Wang | 1112 | 4.86% | 8 | 1.10% |
| Al Viro | 1030 | 4.50% | 57 | 7.87% |
| David Howells | 966 | 4.22% | 5 | 0.69% |
| Linus Torvalds (pre-git) | 950 | 4.16% | 38 | 5.25% |
| Carlos Maiolino | 815 | 3.56% | 3 | 0.41% |
| Mike Kravetz | 801 | 3.50% | 4 | 0.55% |
| Andrew Morton | 747 | 3.27% | 44 | 6.08% |
| Vineeth Remanan Pillai | 558 | 2.44% | 2 | 0.28% |
| Chris Down | 435 | 1.90% | 2 | 0.28% |
| Mike Rapoport | 340 | 1.49% | 6 | 0.83% |
| David M. Grimes | 318 | 1.39% | 1 | 0.14% |
| David Herrmann | 316 | 1.38% | 3 | 0.41% |
| Lukas Czerner | 250 | 1.09% | 2 | 0.28% |
| Theodore Y. Ts'o | 246 | 1.08% | 1 | 0.14% |
| Eric Paris | 219 | 0.96% | 3 | 0.41% |
| Luis R. Rodriguez | 217 | 0.95% | 4 | 0.55% |
| Andreas Gruenbacher | 201 | 0.88% | 5 | 0.69% |
| Miklos Szeredi | 172 | 0.75% | 7 | 0.97% |
| Jeff Layton | 161 | 0.70% | 5 | 0.69% |
| Rik Van Riel | 160 | 0.70% | 4 | 0.55% |
| Vlastimil Babka | 159 | 0.70% | 2 | 0.28% |
| Chuck Lever | 157 | 0.69% | 4 | 0.55% |
| Christoph Hellwig | 152 | 0.66% | 20 | 2.76% |
| Christian Brauner | 142 | 0.62% | 19 | 2.62% |
| Jarkko Sakkinen | 135 | 0.59% | 1 | 0.14% |
| Yang Shi | 128 | 0.56% | 4 | 0.55% |
| Andrea Arcangeli | 126 | 0.55% | 11 | 1.52% |
| Jan Kara | 125 | 0.55% | 5 | 0.69% |
| Nicholas Piggin | 125 | 0.55% | 8 | 1.10% |
| Matt Mackall | 124 | 0.54% | 3 | 0.41% |
| Miaohe Lin | 114 | 0.50% | 5 | 0.69% |
| Axel Rasmussen | 107 | 0.47% | 6 | 0.83% |
| Pavel Emelyanov | 103 | 0.45% | 1 | 0.14% |
| Lee Schermerhorn | 98 | 0.43% | 4 | 0.55% |
| Konstantin Khlebnikov | 85 | 0.37% | 2 | 0.28% |
| Xavier Roche | 70 | 0.31% | 1 | 0.14% |
| David L Stevens | 59 | 0.26% | 2 | 0.28% |
| Amir Goldstein | 58 | 0.25% | 3 | 0.41% |
| Ryan Roberts | 56 | 0.24% | 2 | 0.28% |
| Yu Zhao | 54 | 0.24% | 2 | 0.28% |
| Brian Gerst | 54 | 0.24% | 2 | 0.28% |
| Kairui Song | 51 | 0.22% | 2 | 0.28% |
| Aristeu Sergio Rozanski Filho | 43 | 0.19% | 1 | 0.14% |
| Daniel Verkamp | 40 | 0.17% | 1 | 0.14% |
| Gavin Shan | 39 | 0.17% | 1 | 0.14% |
| Johannes Weiner | 39 | 0.17% | 5 | 0.69% |
| Pavel Tatashin | 36 | 0.16% | 1 | 0.14% |
| Eric W. Biedermann | 36 | 0.16% | 3 | 0.41% |
| Joe Perches | 36 | 0.16% | 4 | 0.55% |
| Giuseppe Scrivano | 33 | 0.14% | 1 | 0.14% |
| Joel A Fernandes | 33 | 0.14% | 2 | 0.28% |
| Christoph Rohland | 31 | 0.14% | 1 | 0.14% |
| Tim Chen | 29 | 0.13% | 1 | 0.14% |
| Sebastian Andrzej Siewior | 29 | 0.13% | 1 | 0.14% |
| Matthew Auld | 29 | 0.13% | 1 | 0.14% |
| Robin Holt | 28 | 0.12% | 1 | 0.14% |
| Dave Hansen | 27 | 0.12% | 2 | 0.28% |
| Gang Li | 23 | 0.10% | 1 | 0.14% |
| Greg Thelen | 23 | 0.10% | 2 | 0.28% |
| Stephen D. Smalley | 22 | 0.10% | 2 | 0.28% |
| Kefeng Wang | 22 | 0.10% | 2 | 0.28% |
| Zach O'Keefe | 20 | 0.09% | 2 | 0.28% |
| Vishal Moola (Oracle) | 20 | 0.09% | 2 | 0.28% |
| Mel Gorman | 20 | 0.09% | 2 | 0.28% |
| Kent Overstreet | 20 | 0.09% | 3 | 0.41% |
| Marc-André Lureau | 19 | 0.08% | 2 | 0.28% |
| Jérémy Lefaure | 19 | 0.08% | 1 | 0.14% |
| Peter Xu | 19 | 0.08% | 4 | 0.55% |
| Deepa Dinamani | 18 | 0.08% | 1 | 0.14% |
| Dmitriy Monakhov | 17 | 0.07% | 1 | 0.14% |
| Tu Jinjiang | 17 | 0.07% | 1 | 0.14% |
| Darrick J. Wong | 16 | 0.07% | 3 | 0.41% |
| Andres Lagar-Cavilla | 15 | 0.07% | 1 | 0.14% |
| Keith Packard | 15 | 0.07% | 1 | 0.14% |
| Andi Kleen | 15 | 0.07% | 2 | 0.28% |
| Shaohua Li | 14 | 0.06% | 1 | 0.14% |
| ZhangPeng | 13 | 0.06% | 2 | 0.28% |
| Arun K S | 12 | 0.05% | 2 | 0.28% |
| Daisuke Nishimura | 12 | 0.05% | 1 | 0.14% |
| Rick Edgecombe | 12 | 0.05% | 1 | 0.14% |
| Arnd Bergmann | 12 | 0.05% | 4 | 0.55% |
| Alan Cox | 12 | 0.05% | 1 | 0.14% |
| Hui Su | 12 | 0.05% | 1 | 0.14% |
| Song Muchun | 11 | 0.05% | 3 | 0.41% |
| Byron Stanoszek | 11 | 0.05% | 1 | 0.14% |
| Souptick Joarder | 11 | 0.05% | 2 | 0.28% |
| Ning Qu | 10 | 0.04% | 1 | 0.14% |
| Alexey Dobriyan | 9 | 0.04% | 3 | 0.41% |
| Arjan van de Ven | 8 | 0.03% | 1 | 0.14% |
| Ingo Molnar | 7 | 0.03% | 4 | 0.55% |
| Aneesh Kumar K.V | 7 | 0.03% | 1 | 0.14% |
| Ira Weiny | 7 | 0.03% | 1 | 0.14% |
| Jie Liu | 7 | 0.03% | 1 | 0.14% |
| Alexey Gladkov | 7 | 0.03% | 1 | 0.14% |
| James Morris | 7 | 0.03% | 2 | 0.28% |
| David Hildenbrand | 7 | 0.03% | 1 | 0.14% |
| Steven Price | 6 | 0.03% | 1 | 0.14% |
| Robin H. Johnson | 6 | 0.03% | 1 | 0.14% |
| Mimi Zohar | 5 | 0.02% | 2 | 0.28% |
| Oleg Nesterov | 5 | 0.02% | 1 | 0.14% |
| Steven Rostedt | 5 | 0.02% | 1 | 0.14% |
| ZhaoLong Wang | 5 | 0.02% | 1 | 0.14% |
| Adrian Bunk | 5 | 0.02% | 3 | 0.41% |
| Barry Song | 5 | 0.02% | 1 | 0.14% |
| Christoph Lameter | 5 | 0.02% | 2 | 0.28% |
| Dan J Williams | 4 | 0.02% | 1 | 0.14% |
| Suren Baghdasaryan | 4 | 0.02% | 1 | 0.14% |
| Thomas Weißschuh | 4 | 0.02% | 1 | 0.14% |
| Michael Marineau | 4 | 0.02% | 1 | 0.14% |
| Eric Sandeen | 4 | 0.02% | 1 | 0.14% |
| Huang Ying | 4 | 0.02% | 2 | 0.28% |
| Sergei Trofimovich | 4 | 0.02% | 1 | 0.14% |
| Geert Uytterhoeven | 4 | 0.02% | 2 | 0.28% |
| Catalin Marinas | 4 | 0.02% | 1 | 0.14% |
| Stephen Hemminger | 4 | 0.02% | 1 | 0.14% |
| Seth Jennings | 4 | 0.02% | 1 | 0.14% |
| Jens Axboe | 3 | 0.01% | 2 | 0.28% |
| Greg Kroah-Hartman | 3 | 0.01% | 1 | 0.14% |
| Anatol Pomozov | 3 | 0.01% | 1 | 0.14% |
| Pekka J Enberg | 3 | 0.01% | 2 | 0.28% |
| Andries E. Brouwer | 3 | 0.01% | 1 | 0.14% |
| Fengguang Wu | 3 | 0.01% | 1 | 0.14% |
| Chen Jun | 3 | 0.01% | 1 | 0.14% |
| Benjamin LaHaise | 3 | 0.01% | 1 | 0.14% |
| Thomas Gleixner | 3 | 0.01% | 1 | 0.14% |
| Colin Ian King | 2 | 0.01% | 1 | 0.14% |
| Sergey Vlasov | 2 | 0.01% | 1 | 0.14% |
| Michel Lespinasse | 2 | 0.01% | 1 | 0.14% |
| Sasha Levin | 2 | 0.01% | 1 | 0.14% |
| Tejun Heo | 2 | 0.01% | 1 | 0.14% |
| JoonSoo Kim | 2 | 0.01% | 1 | 0.14% |
| Mikulas Patocka | 2 | 0.01% | 1 | 0.14% |
| MinChan Kim | 2 | 0.01% | 2 | 0.28% |
| Liu Yuntao | 2 | 0.01% | 1 | 0.14% |
| Helge Deller | 2 | 0.01% | 1 | 0.14% |
| David Rientjes | 2 | 0.01% | 1 | 0.14% |
| Trond Myklebust | 2 | 0.01% | 2 | 0.28% |
| Vladimir Davydov | 2 | 0.01% | 1 | 0.14% |
| Badari Pulavarty | 1 | 0.00% | 1 | 0.14% |
| Toshi Kani | 1 | 0.00% | 1 | 0.14% |
| Will Deacon | 1 | 0.00% | 1 | 0.14% |
| weiping zhang | 1 | 0.00% | 1 | 0.14% |
| Ying Sun | 1 | 0.00% | 1 | 0.14% |
| Michal Hocko | 1 | 0.00% | 1 | 0.14% |
| Bang Li | 1 | 0.00% | 1 | 0.14% |
| Nhat Pham | 1 | 0.00% | 1 | 0.14% |
| Jason A. Donenfeld | 1 | 0.00% | 1 | 0.14% |
| Lorenzo Stoakes | 1 | 0.00% | 1 | 0.14% |
| Wedson Almeida Filho | 1 | 0.00% | 1 | 0.14% |
| Chengguang Xu | 1 | 0.00% | 1 | 0.14% |
| Dave Jones | 1 | 0.00% | 1 | 0.14% |
| Namjae Jeon | 1 | 0.00% | 1 | 0.14% |
| Josef Bacik | 1 | 0.00% | 1 | 0.14% |
| Kuo-Hsin Yang | 1 | 0.00% | 1 | 0.14% |
| Dan Schatzberg | 1 | 0.00% | 1 | 0.14% |
| Sidhartha Kumar | 1 | 0.00% | 1 | 0.14% |
| Paul Gortmaker | 1 | 0.00% | 1 | 0.14% |
| Dave Jiang | 1 | 0.00% | 1 | 0.14% |
| Kamezawa Hiroyuki | 1 | 0.00% | 1 | 0.14% |
| Roberto Sassu | 1 | 0.00% | 1 | 0.14% |
| Akira Yokosawa | 1 | 0.00% | 1 | 0.14% |
| Zach Brown | 1 | 0.00% | 1 | 0.14% |
| Neil Brown | 1 | 0.00% | 1 | 0.14% |
| Américo Wang | 1 | 0.00% | 1 | 0.14% |
| Kay Sievers | 1 | 0.00% | 1 | 0.14% |
| Peter Collingbourne | 1 | 0.00% | 1 | 0.14% |
| Mateusz Nosek | 1 | 0.00% | 1 | 0.14% |
| Total | 22864 | 724 |
/* * 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/fileattr.h> #include <linux/mm.h> #include <linux/random.h> #include <linux/sched/signal.h> #include <linux/export.h> #include <linux/shmem_fs.h> #include <linux/swap.h> #include <linux/uio.h> #include <linux/hugetlb.h> #include <linux/fs_parser.h> #include <linux/swapfile.h> #include <linux/iversion.h> #include "swap.h" static struct vfsmount *shm_mnt __ro_after_init; #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/writeback.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/rmap.h> #include <linux/uuid.h> #include <linux/quotaops.h> #include <linux/rcupdate_wait.h> #include <linux/uaccess.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 /* Pretend that one inode + its dentry occupy this much memory */ #define BOGO_INODE_SIZE 1024 /* 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_rwsem 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 */ }; struct shmem_options { unsigned long long blocks; unsigned long long inodes; struct mempolicy *mpol; kuid_t uid; kgid_t gid; umode_t mode; bool full_inums; int huge; int seen; bool noswap; unsigned short quota_types; struct shmem_quota_limits qlimits; #define SHMEM_SEEN_BLOCKS 1 #define SHMEM_SEEN_INODES 2 #define SHMEM_SEEN_HUGE 4 #define SHMEM_SEEN_INUMS 8 #define SHMEM_SEEN_NOSWAP 16 #define SHMEM_SEEN_QUOTA 32 }; #ifdef CONFIG_TRANSPARENT_HUGEPAGE static unsigned long huge_shmem_orders_always __read_mostly; static unsigned long huge_shmem_orders_madvise __read_mostly; static unsigned long huge_shmem_orders_inherit __read_mostly; static unsigned long huge_shmem_orders_within_size __read_mostly; #endif #ifdef CONFIG_TMPFS static unsigned long shmem_default_max_blocks(void) { return totalram_pages() / 2; } static unsigned long shmem_default_max_inodes(void) { unsigned long nr_pages = totalram_pages(); return min3(nr_pages - totalhigh_pages(), nr_pages / 2, ULONG_MAX / BOGO_INODE_SIZE); } #endif static int shmem_swapin_folio(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, struct mm_struct *fault_mm, vm_fault_t *fault_type); 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_get_folio reports shmem_acct_blocks failure as -ENOSPC not -ENOMEM, * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. */ static inline int shmem_acct_blocks(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 int shmem_inode_acct_blocks(struct inode *inode, long pages) { struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); int err = -ENOSPC; if (shmem_acct_blocks(info->flags, pages)) return err; might_sleep(); /* when quotas */ if (sbinfo->max_blocks) { if (!percpu_counter_limited_add(&sbinfo->used_blocks, sbinfo->max_blocks, pages)) goto unacct; err = dquot_alloc_block_nodirty(inode, pages); if (err) { percpu_counter_sub(&sbinfo->used_blocks, pages); goto unacct; } } else { err = dquot_alloc_block_nodirty(inode, pages); if (err) goto unacct; } return 0; unacct: shmem_unacct_blocks(info->flags, pages); return err; } static void shmem_inode_unacct_blocks(struct inode *inode, long pages) { struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); might_sleep(); /* when quotas */ dquot_free_block_nodirty(inode, pages); if (sbinfo->max_blocks) percpu_counter_sub(&sbinfo->used_blocks, pages); shmem_unacct_blocks(info->flags, pages); } 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 const struct vm_operations_struct shmem_anon_vm_ops; static struct file_system_type shmem_fs_type; bool shmem_mapping(struct address_space *mapping) { return mapping->a_ops == &shmem_aops; } EXPORT_SYMBOL_GPL(shmem_mapping); bool vma_is_anon_shmem(struct vm_area_struct *vma) { return vma->vm_ops == &shmem_anon_vm_ops; } bool vma_is_shmem(struct vm_area_struct *vma) { return vma_is_anon_shmem(vma) || vma->vm_ops == &shmem_vm_ops; } static LIST_HEAD(shmem_swaplist); static DEFINE_MUTEX(shmem_swaplist_mutex); #ifdef CONFIG_TMPFS_QUOTA static int shmem_enable_quotas(struct super_block *sb, unsigned short quota_types) { int type, err = 0; sb_dqopt(sb)->flags |= DQUOT_QUOTA_SYS_FILE | DQUOT_NOLIST_DIRTY; for (type = 0; type < SHMEM_MAXQUOTAS; type++) { if (!(quota_types & (1 << type))) continue; err = dquot_load_quota_sb(sb, type, QFMT_SHMEM, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED); if (err) goto out_err; } return 0; out_err: pr_warn("tmpfs: failed to enable quota tracking (type=%d, err=%d)\n", type, err); for (type--; type >= 0; type--) dquot_quota_off(sb, type); return err; } static void shmem_disable_quotas(struct super_block *sb) { int type; for (type = 0; type < SHMEM_MAXQUOTAS; type++) dquot_quota_off(sb, type); } static struct dquot __rcu **shmem_get_dquots(struct inode *inode) { return SHMEM_I(inode)->i_dquot; } #endif /* CONFIG_TMPFS_QUOTA */ /* * shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and * produces a novel ino for the newly allocated inode. * * It may also be called when making a hard link to permit the space needed by * each dentry. However, in that case, no new inode number is needed since that * internally draws from another pool of inode numbers (currently global * get_next_ino()). This case is indicated by passing NULL as inop. */ #define SHMEM_INO_BATCH 1024 static int shmem_reserve_inode(struct super_block *sb, ino_t *inop) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); ino_t ino; if (!(sb->s_flags & SB_KERNMOUNT)) { raw_spin_lock(&sbinfo->stat_lock); if (sbinfo->max_inodes) { if (sbinfo->free_ispace < BOGO_INODE_SIZE) { raw_spin_unlock(&sbinfo->stat_lock); return -ENOSPC; } sbinfo->free_ispace -= BOGO_INODE_SIZE; } if (inop) { ino = sbinfo->next_ino++; if (unlikely(is_zero_ino(ino))) ino = sbinfo->next_ino++; if (unlikely(!sbinfo->full_inums && ino > UINT_MAX)) { /* * Emulate get_next_ino uint wraparound for * compatibility */ if (IS_ENABLED(CONFIG_64BIT)) pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n", __func__, MINOR(sb->s_dev)); sbinfo->next_ino = 1; ino = sbinfo->next_ino++; } *inop = ino; } raw_spin_unlock(&sbinfo->stat_lock); } else if (inop) { /* * __shmem_file_setup, one of our callers, is lock-free: it * doesn't hold stat_lock in shmem_reserve_inode since * max_inodes is always 0, and is called from potentially * unknown contexts. As such, use a per-cpu batched allocator * which doesn't require the per-sb stat_lock unless we are at * the batch boundary. * * We don't need to worry about inode{32,64} since SB_KERNMOUNT * shmem mounts are not exposed to userspace, so we don't need * to worry about things like glibc compatibility. */ ino_t *next_ino; next_ino = per_cpu_ptr(sbinfo->ino_batch, get_cpu()); ino = *next_ino; if (unlikely(ino % SHMEM_INO_BATCH == 0)) { raw_spin_lock(&sbinfo->stat_lock); ino = sbinfo->next_ino; sbinfo->next_ino += SHMEM_INO_BATCH; raw_spin_unlock(&sbinfo->stat_lock); if (unlikely(is_zero_ino(ino))) ino++; } *inop = ino; *next_ino = ++ino; put_cpu(); } return 0; } static void shmem_free_inode(struct super_block *sb, size_t freed_ispace) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); if (sbinfo->max_inodes) { raw_spin_lock(&sbinfo->stat_lock); sbinfo->free_ispace += BOGO_INODE_SIZE + freed_ispace; raw_spin_unlock(&sbinfo->stat_lock); } } /** * shmem_recalc_inode - recalculate the block usage of an inode * @inode: inode to recalc * @alloced: the change in number of pages allocated to inode * @swapped: the change in number of pages swapped from inode * * 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) */ static void shmem_recalc_inode(struct inode *inode, long alloced, long swapped) { struct shmem_inode_info *info = SHMEM_I(inode); long freed; spin_lock(&info->lock); info->alloced += alloced; info->swapped += swapped; freed = info->alloced - info->swapped - READ_ONCE(inode->i_mapping->nrpages); /* * Special case: whereas normally shmem_recalc_inode() is called * after i_mapping->nrpages has already been adjusted (up or down), * shmem_writepage() has to raise swapped before nrpages is lowered - * to stop a racing shmem_recalc_inode() from thinking that a page has * been freed. Compensate here, to avoid the need for a followup call. */ if (swapped > 0) freed += swapped; if (freed > 0) info->alloced -= freed; spin_unlock(&info->lock); /* The quota case may block */ if (freed > 0) shmem_inode_unacct_blocks(inode, freed); } bool shmem_charge(struct inode *inode, long pages) { struct address_space *mapping = inode->i_mapping; if (shmem_inode_acct_blocks(inode, pages)) return false; /* nrpages adjustment first, then shmem_recalc_inode() when balanced */ xa_lock_irq(&mapping->i_pages); mapping->nrpages += pages; xa_unlock_irq(&mapping->i_pages); shmem_recalc_inode(inode, pages, 0); return true; } void shmem_uncharge(struct inode *inode, long pages) { /* pages argument is currently unused: keep it to help debugging */ /* nrpages adjustment done by __filemap_remove_folio() or caller */ shmem_recalc_inode(inode, 0, 0); } /* * Replace item expected in xarray by a new item, while holding xa_lock. */ static int shmem_replace_entry(struct address_space *mapping, pgoff_t index, void *expected, void *replacement) { XA_STATE(xas, &mapping->i_pages, index); void *item; VM_BUG_ON(!expected); VM_BUG_ON(!replacement); item = xas_load(&xas); if (item != expected) return -ENOENT; xas_store(&xas, replacement); 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) { return xa_load(&mapping->i_pages, index) == 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_HUGEPAGE /* ifdef here to avoid bloating shmem.o when not necessary */ static int shmem_huge __read_mostly = SHMEM_HUGE_NEVER; static bool __shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force, struct mm_struct *mm, unsigned long vm_flags) { loff_t i_size; if (!S_ISREG(inode->i_mode)) return false; if (mm && ((vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &mm->flags))) return false; if (shmem_huge == SHMEM_HUGE_DENY) return false; if (shmem_huge_force || shmem_huge == SHMEM_HUGE_FORCE) return true; switch (SHMEM_SB(inode->i_sb)->huge) { case SHMEM_HUGE_ALWAYS: return true; case SHMEM_HUGE_WITHIN_SIZE: index = round_up(index + 1, HPAGE_PMD_NR); i_size = round_up(i_size_read(inode), PAGE_SIZE); if (i_size >> PAGE_SHIFT >= index) return true; fallthrough; case SHMEM_HUGE_ADVISE: if (mm && (vm_flags & VM_HUGEPAGE)) return true; fallthrough; default: return false; } } bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force, struct mm_struct *mm, unsigned long vm_flags) { if (HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER) return false; return __shmem_is_huge(inode, index, shmem_huge_force, mm, vm_flags); } #if defined(CONFIG_SYSFS) static int shmem_parse_huge(const char *str) { if (!strcmp(str, "never")) return SHMEM_HUGE_NEVER; if (!strcmp(str, "always")) return SHMEM_HUGE_ALWAYS; if (!strcmp(str, "within_size")) return SHMEM_HUGE_WITHIN_SIZE; if (!strcmp(str, "advise")) return SHMEM_HUGE_ADVISE; if (!strcmp(str, "deny")) return SHMEM_HUGE_DENY; if (!strcmp(str, "force")) return SHMEM_HUGE_FORCE; return -EINVAL; } #endif #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS) static const char *shmem_format_huge(int huge) { switch (huge) { case SHMEM_HUGE_NEVER: return "never"; case SHMEM_HUGE_ALWAYS: return "always"; case SHMEM_HUGE_WITHIN_SIZE: return "within_size"; case SHMEM_HUGE_ADVISE: return "advise"; case SHMEM_HUGE_DENY: return "deny"; case SHMEM_HUGE_FORCE: return "force"; default: VM_BUG_ON(1); return "bad_val"; } } #endif static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, struct shrink_control *sc, unsigned long nr_to_split) { LIST_HEAD(list), *pos, *next; LIST_HEAD(to_remove); struct inode *inode; struct shmem_inode_info *info; struct folio *folio; unsigned long batch = sc ? sc->nr_to_scan : 128; int 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); 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); goto next; } list_move(&info->shrinklist, &list); next: sbinfo->shrinklist_len--; 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; pgoff_t index; info = list_entry(pos, struct shmem_inode_info, shrinklist); inode = &info->vfs_inode; if (nr_to_split && split >= nr_to_split) goto move_back; index = (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT; folio = filemap_get_folio(inode->i_mapping, index); if (IS_ERR(folio)) goto drop; /* No huge page at the end of the file: nothing to split */ if (!folio_test_large(folio)) { folio_put(folio); goto drop; } /* * Move the inode on the list back to shrinklist if we failed * to lock the page at this time. * * Waiting for the lock may lead to deadlock in the * reclaim path. */ if (!folio_trylock(folio)) { folio_put(folio); goto move_back; } ret = split_folio(folio); folio_unlock(folio); folio_put(folio); /* If split failed move the inode on the list back to shrinklist */ if (ret) goto move_back; split++; drop: list_del_init(&info->shrinklist); goto put; move_back: /* * Make sure the inode is either on the global list or deleted * from any local list before iput() since it could be deleted * in another thread once we put the inode (then the local list * is corrupted). */ spin_lock(&sbinfo->shrinklist_lock); list_move(&info->shrinklist, &sbinfo->shrinklist); sbinfo->shrinklist_len++; spin_unlock(&sbinfo->shrinklist_lock); put: iput(inode); } return split; } static long shmem_unused_huge_scan(struct super_block *sb, struct shrink_control *sc) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); if (!READ_ONCE(sbinfo->shrinklist_len)) return SHRINK_STOP; return shmem_unused_huge_shrink(sbinfo, sc, 0); } static long shmem_unused_huge_count(struct super_block *sb, struct shrink_control *sc) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); return READ_ONCE(sbinfo->shrinklist_len); } #else /* !CONFIG_TRANSPARENT_HUGEPAGE */ #define shmem_huge SHMEM_HUGE_DENY static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, struct shrink_control *sc, unsigned long nr_to_split) { return 0; } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ /* * Somewhat like filemap_add_folio, but error if expected item has gone. */ static int shmem_add_to_page_cache(struct folio *folio, struct address_space *mapping, pgoff_t index, void *expected, gfp_t gfp) { XA_STATE_ORDER(xas, &mapping->i_pages, index, folio_order(folio)); long nr = folio_nr_pages(folio); VM_BUG_ON_FOLIO(index != round_down(index, nr), folio); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); VM_BUG_ON_FOLIO(!folio_test_swapbacked(folio), folio); VM_BUG_ON(expected && folio_test_large(folio)); folio_ref_add(folio, nr); folio->mapping = mapping; folio->index = index; gfp &= GFP_RECLAIM_MASK; folio_throttle_swaprate(folio, gfp); do { xas_lock_irq(&xas); if (expected != xas_find_conflict(&xas)) { xas_set_err(&xas, -EEXIST); goto unlock; } if (expected && xas_find_conflict(&xas)) { xas_set_err(&xas, -EEXIST); goto unlock; } xas_store(&xas, folio); if (xas_error(&xas)) goto unlock; if (folio_test_pmd_mappable(folio)) __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, nr); __lruvec_stat_mod_folio(folio, NR_FILE_PAGES, nr); __lruvec_stat_mod_folio(folio, NR_SHMEM, nr); mapping->nrpages += nr; unlock: xas_unlock_irq(&xas); } while (xas_nomem(&xas, gfp)); if (xas_error(&xas)) { folio->mapping = NULL; folio_ref_sub(folio, nr); return xas_error(&xas); } return 0; } /* * Somewhat like filemap_remove_folio, but substitutes swap for @folio. */ static void shmem_delete_from_page_cache(struct folio *folio, void *radswap) { struct address_space *mapping = folio->mapping; long nr = folio_nr_pages(folio); int error; xa_lock_irq(&mapping->i_pages); error = shmem_replace_entry(mapping, folio->index, folio, radswap); folio->mapping = NULL; mapping->nrpages -= nr; __lruvec_stat_mod_folio(folio, NR_FILE_PAGES, -nr); __lruvec_stat_mod_folio(folio, NR_SHMEM, -nr); xa_unlock_irq(&mapping->i_pages); folio_put(folio); BUG_ON(error); } /* * Remove swap entry from page cache, free the swap and its page cache. */ static int shmem_free_swap(struct address_space *mapping, pgoff_t index, void *radswap) { void *old; old = xa_cmpxchg_irq(&mapping->i_pages, index, radswap, NULL, 0); if (old != radswap) return -ENOENT; free_swap_and_cache(radix_to_swp_entry(radswap)); return 0; } /* * Determine (in bytes) how many of the shmem object's pages mapped by the * given offsets are swapped out. * * This is safe to call without i_rwsem or the i_pages lock thanks to RCU, * as long as the inode doesn't go away and racy results are not a problem. */ unsigned long shmem_partial_swap_usage(struct address_space *mapping, pgoff_t start, pgoff_t end) { XA_STATE(xas, &mapping->i_pages, start); struct page *page; unsigned long swapped = 0; unsigned long max = end - 1; rcu_read_lock(); xas_for_each(&xas, page, max) { if (xas_retry(&xas, page)) continue; if (xa_is_value(page)) swapped++; if (xas.xa_index == max) break; if (need_resched()) { xas_pause(&xas); cond_resched_rcu(); } } rcu_read_unlock(); return swapped << PAGE_SHIFT; } /* * Determine (in bytes) how many of the shmem object's pages mapped by the * given vma is swapped out. * * This is safe to call without i_rwsem or the i_pages lock thanks to RCU, * as long as the inode doesn't go away and racy results are not a problem. */ unsigned long shmem_swap_usage(struct vm_area_struct *vma) { struct inode *inode = file_inode(vma->vm_file); struct shmem_inode_info *info = SHMEM_I(inode); struct address_space *mapping = inode->i_mapping; unsigned long swapped; /* Be careful as we don't hold info->lock */ swapped = READ_ONCE(info->swapped); /* * The easier cases are when the shmem object has nothing in swap, or * the vma maps it whole. Then we can simply use the stats that we * already track. */ if (!swapped) return 0; if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size) return swapped << PAGE_SHIFT; /* Here comes the more involved part */ return shmem_partial_swap_usage(mapping, vma->vm_pgoff, vma->vm_pgoff + vma_pages(vma)); } /* * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. */ void shmem_unlock_mapping(struct address_space *mapping) { struct folio_batch fbatch; pgoff_t index = 0; folio_batch_init(&fbatch); /* * Minor point, but we might as well stop if someone else SHM_LOCKs it. */ while (!mapping_unevictable(mapping) && filemap_get_folios(mapping, &index, ~0UL, &fbatch)) { check_move_unevictable_folios(&fbatch); folio_batch_release(&fbatch); cond_resched(); } } static struct folio *shmem_get_partial_folio(struct inode *inode, pgoff_t index) { struct folio *folio; /* * At first avoid shmem_get_folio(,,,SGP_READ): that fails * beyond i_size, and reports fallocated folios as holes. */ folio = filemap_get_entry(inode->i_mapping, index); if (!folio) return folio; if (!xa_is_value(folio)) { folio_lock(folio); if (folio->mapping == inode->i_mapping) return folio; /* The folio has been swapped out */ folio_unlock(folio); folio_put(folio); } /* * But read a folio back from swap if any of it is within i_size * (although in some cases this is just a waste of time). */ folio = NULL; shmem_get_folio(inode, index, &folio, SGP_READ); return folio; } /* * Remove range of pages and swap entries from page cache, and free them. * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. */ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, bool unfalloc) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; pgoff_t end = (lend + 1) >> PAGE_SHIFT; struct folio_batch fbatch; pgoff_t indices[PAGEVEC_SIZE]; struct folio *folio; bool same_folio; long nr_swaps_freed = 0; pgoff_t index; int i; if (lend == -1) end = -1; /* unsigned, so actually very big */ if (info->fallocend > start && info->fallocend <= end && !unfalloc) info->fallocend = start; folio_batch_init(&fbatch); index = start; while (index < end && find_lock_entries(mapping, &index, end - 1, &fbatch, indices)) { for (i = 0; i < folio_batch_count(&fbatch); i++) { folio = fbatch.folios[i]; if (xa_is_value(folio)) { if (unfalloc) continue; nr_swaps_freed += !shmem_free_swap(mapping, indices[i], folio); continue; } if (!unfalloc || !folio_test_uptodate(folio)) truncate_inode_folio(mapping, folio); folio_unlock(folio); } folio_batch_remove_exceptionals(&fbatch); folio_batch_release(&fbatch); cond_resched(); } /* * When undoing a failed fallocate, we want none of the partial folio * zeroing and splitting below, but shall want to truncate the whole * folio when !uptodate indicates that it was added by this fallocate, * even when [lstart, lend] covers only a part of the folio. */ if (unfalloc) goto whole_folios; same_folio = (lstart >> PAGE_SHIFT) == (lend >> PAGE_SHIFT); folio = shmem_get_partial_folio(inode, lstart >> PAGE_SHIFT); if (folio) { same_folio = lend < folio_pos(folio) + folio_size(folio); folio_mark_dirty(folio); if (!truncate_inode_partial_folio(folio, lstart, lend)) { start = folio_next_index(folio); if (same_folio) end = folio->index; } folio_unlock(folio); folio_put(folio); folio = NULL; } if (!same_folio) folio = shmem_get_partial_folio(inode, lend >> PAGE_SHIFT); if (folio) { folio_mark_dirty(folio); if (!truncate_inode_partial_folio(folio, lstart, lend)) end = folio->index; folio_unlock(folio); folio_put(folio); } whole_folios: index = start; while (index < end) { cond_resched(); if (!find_get_entries(mapping, &index, end - 1, &fbatch, indices)) { /* If all gone or hole-punch or unfalloc, we're done */ if (index == start || end != -1) break; /* But if truncating, restart to make sure all gone */ index = start; continue; } for (i = 0; i < folio_batch_count(&fbatch); i++) { folio = fbatch.folios[i]; if (xa_is_value(folio)) { if (unfalloc) continue; if (shmem_free_swap(mapping, indices[i], folio)) { /* Swap was replaced by page: retry */ index = indices[i]; break; } nr_swaps_freed++; continue; } folio_lock(folio); if (!unfalloc || !folio_test_uptodate(folio)) { if (folio_mapping(folio) != mapping) { /* Page was replaced by swap: retry */ folio_unlock(folio); index = indices[i]; break; } VM_BUG_ON_FOLIO(folio_test_writeback(folio), folio); if (!folio_test_large(folio)) { truncate_inode_folio(mapping, folio); } else if (truncate_inode_partial_folio(folio, lstart, lend)) { /* * If we split a page, reset the loop so * that we pick up the new sub pages. * Otherwise the THP was entirely * dropped or the target range was * zeroed, so just continue the loop as * is. */ if (!folio_test_large(folio)) { folio_unlock(folio); index = start; break; } } } folio_unlock(folio); } folio_batch_remove_exceptionals(&fbatch); folio_batch_release(&fbatch); } shmem_recalc_inode(inode, 0, -nr_swaps_freed); } void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) { shmem_undo_range(inode, lstart, lend, false); inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); inode_inc_iversion(inode); } EXPORT_SYMBOL_GPL(shmem_truncate_range); static int shmem_getattr(struct mnt_idmap *idmap, 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) shmem_recalc_inode(inode, 0, 0); if (info->fsflags & FS_APPEND_FL) stat->attributes |= STATX_ATTR_APPEND; if (info->fsflags & FS_IMMUTABLE_FL) stat->attributes |= STATX_ATTR_IMMUTABLE; if (info->fsflags & FS_NODUMP_FL) stat->attributes |= STATX_ATTR_NODUMP; stat->attributes_mask |= (STATX_ATTR_APPEND | STATX_ATTR_IMMUTABLE | STATX_ATTR_NODUMP); generic_fillattr(idmap, request_mask, inode, stat); if (shmem_is_huge(inode, 0, false, NULL, 0)) stat->blksize = HPAGE_PMD_SIZE; if (request_mask & STATX_BTIME) { stat->result_mask |= STATX_BTIME; stat->btime.tv_sec = info->i_crtime.tv_sec; stat->btime.tv_nsec = info->i_crtime.tv_nsec; } return 0; } static int shmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr) { struct inode *inode = d_inode(dentry); struct shmem_inode_info *info = SHMEM_I(inode); int error; bool update_mtime = false; bool update_ctime = true; error = setattr_prepare(idmap, dentry, attr); if (error) return error; if ((info->seals & F_SEAL_EXEC) && (attr->ia_valid & ATTR_MODE)) { if ((inode->i_mode ^ attr->ia_mode) & 0111) { return -EPERM; } } 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_rwsem */ 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); update_mtime = true; } else { update_ctime = false; } 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); } } if (is_quota_modification(idmap, inode, attr)) { error = dquot_initialize(inode); if (error) return error; } /* Transfer quota accounting */ if (i_uid_needs_update(idmap, attr, inode) || i_gid_needs_update(idmap, attr, inode)) { error = dquot_transfer(idmap, inode, attr); if (error) return error; } setattr_copy(idmap, inode, attr); if (attr->ia_valid & ATTR_MODE) error = posix_acl_chmod(idmap, dentry, inode->i_mode); if (!error && update_ctime) { inode_set_ctime_current(inode); if (update_mtime) inode_set_mtime_to_ts(inode, inode_get_ctime(inode)); inode_inc_iversion(inode); } 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); size_t freed = 0; if (shmem_mapping(inode->i_mapping)) { shmem_unacct_size(info->flags, inode->i_size); inode->i_size = 0; mapping_set_exiting(inode->i_mapping); shmem_truncate_range(inode, 0, (loff_t)-1); if (!list_empty(&info->shrinklist)) { spin_lock(&sbinfo->shrinklist_lock); if (!list_empty(&info->shrinklist)) { list_del_init(&info->shrinklist); sbinfo->shrinklist_len--; } spin_unlock(&sbinfo->shrinklist_lock); } while (!list_empty(&info->swaplist)) { /* Wait while shmem_unuse() is scanning this inode... */ wait_var_event(&info->stop_eviction, !atomic_read(&info->stop_eviction)); mutex_lock(&shmem_swaplist_mutex); /* ...but beware of the race if we peeked too early */ if (!atomic_read(&info->stop_eviction)) list_del_init(&info->swaplist); mutex_unlock(&shmem_swaplist_mutex); } } simple_xattrs_free(&info->xattrs, sbinfo->max_inodes ? &freed : NULL); shmem_free_inode(inode->i_sb, freed); WARN_ON(inode->i_blocks); clear_inode(inode); #ifdef CONFIG_TMPFS_QUOTA dquot_free_inode(inode); dquot_drop(inode); #endif } static int shmem_find_swap_entries(struct address_space *mapping, pgoff_t start, struct folio_batch *fbatch, pgoff_t *indices, unsigned int type) { XA_STATE(xas, &mapping->i_pages, start); struct folio *folio; swp_entry_t entry; rcu_read_lock(); xas_for_each(&xas, folio, ULONG_MAX) { if (xas_retry(&xas, folio)) continue; if (!xa_is_value(folio)) continue; entry = radix_to_swp_entry(folio); /* * swapin error entries can be found in the mapping. But they're * deliberately ignored here as we've done everything we can do. */ if (swp_type(entry) != type) continue; indices[folio_batch_count(fbatch)] = xas.xa_index; if (!folio_batch_add(fbatch, folio)) break; if (need_resched()) { xas_pause(&xas); cond_resched_rcu(); } } rcu_read_unlock(); return xas.xa_index; } /* * Move the swapped pages for an inode to page cache. Returns the count * of pages swapped in, or the error in case of failure. */ static int shmem_unuse_swap_entries(struct inode *inode, struct folio_batch *fbatch, pgoff_t *indices) { int i = 0; int ret = 0; int error = 0; struct address_space *mapping = inode->i_mapping; for (i = 0; i < folio_batch_count(fbatch); i++) { struct folio *folio = fbatch->folios[i]; if (!xa_is_value(folio)) continue; error = shmem_swapin_folio(inode, indices[i], &folio, SGP_CACHE, mapping_gfp_mask(mapping), NULL, NULL); if (error == 0) { folio_unlock(folio); folio_put(folio); ret++; } if (error == -ENOMEM) break; error = 0; } return error ? error : ret; } /* * If swap found in inode, free it and move page from swapcache to filecache. */ static int shmem_unuse_inode(struct inode *inode, unsigned int type) { struct address_space *mapping = inode->i_mapping; pgoff_t start = 0; struct folio_batch fbatch; pgoff_t indices[PAGEVEC_SIZE]; int ret = 0; do { folio_batch_init(&fbatch); shmem_find_swap_entries(mapping, start, &fbatch, indices, type); if (folio_batch_count(&fbatch) == 0) { ret = 0; break; } ret = shmem_unuse_swap_entries(inode, &fbatch, indices); if (ret < 0) break; start = indices[folio_batch_count(&fbatch) - 1]; } while (true); return ret; } /* * Read all the shared memory data that resides in the swap * device 'type' back into memory, so the swap device can be * unused. */ int shmem_unuse(unsigned int type) { struct shmem_inode_info *info, *next; int error = 0; if (list_empty(&shmem_swaplist)) return 0; mutex_lock(&shmem_swaplist_mutex); list_for_each_entry_safe(info, next, &shmem_swaplist, swaplist) { if (!info->swapped) { list_del_init(&info->swaplist); continue; } /* * Drop the swaplist mutex while searching the inode for swap; * but before doing so, make sure shmem_evict_inode() will not * remove placeholder inode from swaplist, nor let it be freed * (igrab() would protect from unlink, but not from unmount). */ atomic_inc(&info->stop_eviction); mutex_unlock(&shmem_swaplist_mutex); error = shmem_unuse_inode(&info->vfs_inode, type); cond_resched(); mutex_lock(&shmem_swaplist_mutex); next = list_next_entry(info, swaplist); if (!info->swapped) list_del_init(&info->swaplist); if (atomic_dec_and_test(&info->stop_eviction)) wake_up_var(&info->stop_eviction); if (error) break; } mutex_unlock(&shmem_swaplist_mutex); return error; } /* * Move the page from the page cache to the swap cache. */ static int shmem_writepage(struct page *page, struct writeback_control *wbc) { struct folio *folio = page_folio(page); struct address_space *mapping = folio->mapping; struct inode *inode = mapping->host; struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); swp_entry_t swap; pgoff_t index; /* * 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 (WARN_ON_ONCE(!wbc->for_reclaim)) goto redirty; if (WARN_ON_ONCE((info->flags & VM_LOCKED) || sbinfo->noswap)) goto redirty; if (!total_swap_pages) goto redirty; /* * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages, * and its shmem_writeback() needs them to be split when swapping. */ if (folio_test_large(folio)) { /* Ensure the subpages are still dirty */ folio_test_set_dirty(folio); if (split_huge_page(page) < 0) goto redirty; folio = page_folio(page); folio_clear_dirty(folio); } index = folio->index; /* * 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 folio arriving here is now to initialize it and write it. * * That's okay for a folio already fallocated earlier, but if we have * not yet completed the fallocation, then (a) we want to keep track * of this folio 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 folio, and let shmem_fallocate() quit when too many. */ if (!folio_test_uptodate(folio)) { 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; } folio_zero_range(folio, 0, folio_size(folio)); flush_dcache_folio(folio); folio_mark_uptodate(folio); } swap = folio_alloc_swap(folio); if (!swap.val) goto redirty; /* * Add inode to shmem_unuse()'s list of swapped-out inodes, * if it's not already there. Do it now before the folio is * moved to swap cache, when its pagelock no longer protects * the inode from eviction. But don't unlock the mutex until * we've incremented swapped, because shmem_unuse_inode() will * prune a !swapped inode from the swaplist under this mutex. */ mutex_lock(&shmem_swaplist_mutex); if (list_empty(&info->swaplist)) list_add(&info->swaplist, &shmem_swaplist); if (add_to_swap_cache(folio, swap, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN, NULL) == 0) { shmem_recalc_inode(inode, 0, 1); swap_shmem_alloc(swap); shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap)); mutex_unlock(&shmem_swaplist_mutex); BUG_ON(folio_mapped(folio)); return swap_writepage(&folio->page, wbc); } mutex_unlock(&shmem_swaplist_mutex); put_swap_folio(folio, swap); redirty: folio_mark_dirty(folio); if (wbc->for_reclaim) return AOP_WRITEPAGE_ACTIVATE; /* Return with folio locked */ folio_unlock(folio); 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) { raw_spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ mpol = sbinfo->mpol; mpol_get(mpol); raw_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 */ static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, pgoff_t index, unsigned int order, pgoff_t *ilx); static struct folio *shmem_swapin_cluster(swp_entry_t swap, gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { struct mempolicy *mpol; pgoff_t ilx; struct folio *folio; mpol = shmem_get_pgoff_policy(info, index, 0, &ilx); folio = swap_cluster_readahead(swap, gfp, mpol, ilx); mpol_cond_put(mpol); return folio; } /* * Make sure huge_gfp is always more limited than limit_gfp. * Some of the flags set permissions, while others set limitations. */ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) { gfp_t allowflags = __GFP_IO | __GFP_FS | __GFP_RECLAIM; gfp_t denyflags = __GFP_NOWARN | __GFP_NORETRY; gfp_t zoneflags = limit_gfp & GFP_ZONEMASK; gfp_t result = huge_gfp & ~(allowflags | GFP_ZONEMASK); /* Allow allocations only from the originally specified zones. */ result |= zoneflags; /* * Minimize the result gfp by taking the union with the deny flags, * and the intersection of the allow flags. */ result |= (limit_gfp & denyflags); result |= (huge_gfp & limit_gfp) & allowflags; return result; } #ifdef CONFIG_TRANSPARENT_HUGEPAGE unsigned long shmem_allowable_huge_orders(struct inode *inode, struct vm_area_struct *vma, pgoff_t index, bool global_huge) { unsigned long mask = READ_ONCE(huge_shmem_orders_always); unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size); unsigned long vm_flags = vma->vm_flags; loff_t i_size; int order; if ((vm_flags & VM_NOHUGEPAGE) || test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags)) return 0; /* If the hardware/firmware marked hugepage support disabled. */ if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED)) return 0; /* * Following the 'deny' semantics of the top level, force the huge * option off from all mounts. */ if (shmem_huge == SHMEM_HUGE_DENY) return 0; /* * Only allow inherit orders if the top-level value is 'force', which * means non-PMD sized THP can not override 'huge' mount option now. */ if (shmem_huge == SHMEM_HUGE_FORCE) return READ_ONCE(huge_shmem_orders_inherit); /* Allow mTHP that will be fully within i_size. */ order = highest_order(within_size_orders); while (within_size_orders) { index = round_up(index + 1, order); i_size = round_up(i_size_read(inode), PAGE_SIZE); if (i_size >> PAGE_SHIFT >= index) { mask |= within_size_orders; break; } order = next_order(&within_size_orders, order); } if (vm_flags & VM_HUGEPAGE) mask |= READ_ONCE(huge_shmem_orders_madvise); if (global_huge) mask |= READ_ONCE(huge_shmem_orders_inherit); return THP_ORDERS_ALL_FILE_DEFAULT & mask; } static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault *vmf, struct address_space *mapping, pgoff_t index, unsigned long orders) { struct vm_area_struct *vma = vmf->vma; pgoff_t aligned_index; unsigned long pages; int order; orders = thp_vma_suitable_orders(vma, vmf->address, orders); if (!orders) return 0; /* Find the highest order that can add into the page cache */ order = highest_order(orders); while (orders) { pages = 1UL << order; aligned_index = round_down(index, pages); if (!xa_find(&mapping->i_pages, &aligned_index, aligned_index + pages - 1, XA_PRESENT)) break; order = next_order(&orders, order); } return orders; } #else static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault *vmf, struct address_space *mapping, pgoff_t index, unsigned long orders) { return 0; } #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static struct folio *shmem_alloc_folio(gfp_t gfp, int order, struct shmem_inode_info *info, pgoff_t index) { struct mempolicy *mpol; pgoff_t ilx; struct folio *folio; mpol = shmem_get_pgoff_policy(info, index, order, &ilx); folio = folio_alloc_mpol(gfp, order, mpol, ilx, numa_node_id()); mpol_cond_put(mpol); return folio; } static struct folio *shmem_alloc_and_add_folio(struct vm_fault *vmf, gfp_t gfp, struct inode *inode, pgoff_t index, struct mm_struct *fault_mm, unsigned long orders) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct vm_area_struct *vma = vmf ? vmf->vma : NULL; unsigned long suitable_orders = 0; struct folio *folio = NULL; long pages; int error, order; if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) orders = 0; if (orders > 0) { if (vma && vma_is_anon_shmem(vma)) { suitable_orders = shmem_suitable_orders(inode, vmf, mapping, index, orders); } else if (orders & BIT(HPAGE_PMD_ORDER)) { pages = HPAGE_PMD_NR; suitable_orders = BIT(HPAGE_PMD_ORDER); index = round_down(index, HPAGE_PMD_NR); /* * Check for conflict before waiting on a huge allocation. * Conflict might be that a huge page has just been allocated * and added to page cache by a racing thread, or that there * is already at least one small page in the huge extent. * Be careful to retry when appropriate, but not forever! * Elsewhere -EEXIST would be the right code, but not here. */ if (xa_find(&mapping->i_pages, &index, index + HPAGE_PMD_NR - 1, XA_PRESENT)) return ERR_PTR(-E2BIG); } order = highest_order(suitable_orders); while (suitable_orders) { pages = 1UL << order; index = round_down(index, pages); folio = shmem_alloc_folio(gfp, order, info, index); if (folio) goto allocated; if (pages == HPAGE_PMD_NR) count_vm_event(THP_FILE_FALLBACK); #ifdef CONFIG_TRANSPARENT_HUGEPAGE count_mthp_stat(order, MTHP_STAT_SHMEM_FALLBACK); #endif order = next_order(&suitable_orders, order); } } else { pages = 1; folio = shmem_alloc_folio(gfp, 0, info, index); } if (!folio) return ERR_PTR(-ENOMEM); allocated: __folio_set_locked(folio); __folio_set_swapbacked(folio); gfp &= GFP_RECLAIM_MASK; error = mem_cgroup_charge(folio, fault_mm, gfp); if (error) { if (xa_find(&mapping->i_pages, &index, index + pages - 1, XA_PRESENT)) { error = -EEXIST; } else if (pages > 1) { if (pages == HPAGE_PMD_NR) { count_vm_event(THP_FILE_FALLBACK); count_vm_event(THP_FILE_FALLBACK_CHARGE); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK); count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK_CHARGE); #endif } goto unlock; } error = shmem_add_to_page_cache(folio, mapping, index, NULL, gfp); if (error) goto unlock; error = shmem_inode_acct_blocks(inode, pages); if (error) { struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); long freed; /* * Try to reclaim some space by splitting a few * large folios beyond i_size on the filesystem. */ shmem_unused_huge_shrink(sbinfo, NULL, 2); /* * And do a shmem_recalc_inode() to account for freed pages: * except our folio is there in cache, so not quite balanced. */ spin_lock(&info->lock); freed = pages + info->alloced - info->swapped - READ_ONCE(mapping->nrpages); if (freed > 0) info->alloced -= freed; spin_unlock(&info->lock); if (freed > 0) shmem_inode_unacct_blocks(inode, freed); error = shmem_inode_acct_blocks(inode, pages); if (error) { filemap_remove_folio(folio); goto unlock; } } shmem_recalc_inode(inode, pages, 0); folio_add_lru(folio); return folio; unlock: folio_unlock(folio); folio_put(folio); return ERR_PTR(error); } /* * When a page is moved from swapcache to shmem filecache (either by the * usual swapin of shmem_get_folio_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_folio(struct folio *folio, gfp_t gfp) { return folio_zonenum(folio) > gfp_zone(gfp); } static int shmem_replace_folio(struct folio **foliop, gfp_t gfp, struct shmem_inode_info *info, pgoff_t index) { struct folio *old, *new; struct address_space *swap_mapping; swp_entry_t entry; pgoff_t swap_index; int error; old = *foliop; entry = old->swap; swap_index = swap_cache_index(entry); swap_mapping = swap_address_space(entry); /* * 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; VM_BUG_ON_FOLIO(folio_test_large(old), old); new = shmem_alloc_folio(gfp, 0, info, index); if (!new) return -ENOMEM; folio_get(new); folio_copy(new, old); flush_dcache_folio(new); __folio_set_locked(new); __folio_set_swapbacked(new); folio_mark_uptodate(new); new->swap = entry; folio_set_swapcache(new); /* * Our caller will very soon move newpage out of swapcache, but it's * a nice clean interface for us to replace oldpage by newpage there. */ xa_lock_irq(&swap_mapping->i_pages); error = shmem_replace_entry(swap_mapping, swap_index, old, new); if (!error) { mem_cgroup_replace_folio(old, new); __lruvec_stat_mod_folio(new, NR_FILE_PAGES, 1); __lruvec_stat_mod_folio(new, NR_SHMEM, 1); __lruvec_stat_mod_folio(old, NR_FILE_PAGES, -1); __lruvec_stat_mod_folio(old, NR_SHMEM, -1); } xa_unlock_irq(&swap_mapping->i_pages); if (unlikely(error)) { /* * Is this possible? I think not, now that our callers check * both PageSwapCache and page_private after getting page lock; * but be defensive. Reverse old to newpage for clear and free. */ old = new; } else { folio_add_lru(new); *foliop = new; } folio_clear_swapcache(old); old->private = NULL; folio_unlock(old); folio_put_refs(old, 2); return error; } static void shmem_set_folio_swapin_error(struct inode *inode, pgoff_t index, struct folio *folio, swp_entry_t swap) { struct address_space *mapping = inode->i_mapping; swp_entry_t swapin_error; void *old; swapin_error = make_poisoned_swp_entry(); old = xa_cmpxchg_irq(&mapping->i_pages, index, swp_to_radix_entry(swap), swp_to_radix_entry(swapin_error), 0); if (old != swp_to_radix_entry(swap)) return; folio_wait_writeback(folio); delete_from_swap_cache(folio); /* * Don't treat swapin error folio as alloced. Otherwise inode->i_blocks * won't be 0 when inode is released and thus trigger WARN_ON(i_blocks) * in shmem_evict_inode(). */ shmem_recalc_inode(inode, -1, -1); swap_free(swap); } /* * Swap in the folio pointed to by *foliop. * Caller has to make sure that *foliop contains a valid swapped folio. * Returns 0 and the folio in foliop if success. On failure, returns the * error code and NULL in *foliop. */ static int shmem_swapin_folio(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, struct mm_struct *fault_mm, vm_fault_t *fault_type) { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct swap_info_struct *si; struct folio *folio = NULL; swp_entry_t swap; int error; VM_BUG_ON(!*foliop || !xa_is_value(*foliop)); swap = radix_to_swp_entry(*foliop); *foliop = NULL; if (is_poisoned_swp_entry(swap)) return -EIO; si = get_swap_device(swap); if (!si) { if (!shmem_confirm_swap(mapping, index, swap)) return -EEXIST; else return -EINVAL; } /* Look it up and read it in.. */ folio = swap_cache_get_folio(swap, NULL, 0); if (!folio) { /* Or update major stats only when swapin succeeds?? */ if (fault_type) { *fault_type |= VM_FAULT_MAJOR; count_vm_event(PGMAJFAULT); count_memcg_event_mm(fault_mm, PGMAJFAULT); } /* Here we actually start the io */ folio = shmem_swapin_cluster(swap, gfp, info, index); if (!folio) { error = -ENOMEM; goto failed; } } /* We have to do this with folio locked to prevent races */ folio_lock(folio); if (!folio_test_swapcache(folio) || folio->swap.val != swap.val || !shmem_confirm_swap(mapping, index, swap)) { error = -EEXIST; goto unlock; } if (!folio_test_uptodate(folio)) { error = -EIO; goto failed; } folio_wait_writeback(folio); /* * Some architectures may have to restore extra metadata to the * folio after reading from swap. */ arch_swap_restore(folio_swap(swap, folio), folio); if (shmem_should_replace_folio(folio, gfp)) { error = shmem_replace_folio(&folio, gfp, info, index); if (error) goto failed; } error = shmem_add_to_page_cache(folio, mapping, index, swp_to_radix_entry(swap), gfp); if (error) goto failed; shmem_recalc_inode(inode, 0, -1); if (sgp == SGP_WRITE) folio_mark_accessed(folio); delete_from_swap_cache(folio); folio_mark_dirty(folio); swap_free(swap); put_swap_device(si); *foliop = folio; return 0; failed: if (!shmem_confirm_swap(mapping, index, swap)) error = -EEXIST; if (error == -EIO) shmem_set_folio_swapin_error(inode, index, folio, swap); unlock: if (folio) { folio_unlock(folio); folio_put(folio); } put_swap_device(si); return error; } /* * shmem_get_folio_gfp - find page in cache, or get from swap, or allocate * * If we allocate a new one we do not mark it dirty. That's up to the * vm. If we swap it in we mark it dirty since we also free the swap * entry since a page cannot live in both the swap and page cache. * * vmf and fault_type are only supplied by shmem_fault: otherwise they are NULL. */ static int shmem_get_folio_gfp(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp, gfp_t gfp, struct vm_fault *vmf, vm_fault_t *fault_type) { struct vm_area_struct *vma = vmf ? vmf->vma : NULL; struct mm_struct *fault_mm; struct folio *folio; int error; bool alloced, huge; unsigned long orders = 0; if (WARN_ON_ONCE(!shmem_mapping(inode->i_mapping))) return -EINVAL; if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) return -EFBIG; repeat: if (sgp <= SGP_CACHE && ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) return -EINVAL; alloced = false; fault_mm = vma ? vma->vm_mm : NULL; folio = filemap_get_entry(inode->i_mapping, index); if (folio && vma && userfaultfd_minor(vma)) { if (!xa_is_value(folio)) folio_put(folio); *fault_type = handle_userfault(vmf, VM_UFFD_MINOR); return 0; } if (xa_is_value(folio)) { error = shmem_swapin_folio(inode, index, &folio, sgp, gfp, fault_mm, fault_type); if (error == -EEXIST) goto repeat; *foliop = folio; return error; } if (folio) { folio_lock(folio); /* Has the folio been truncated or swapped out? */ if (unlikely(folio->mapping != inode->i_mapping)) { folio_unlock(folio); folio_put(folio); goto repeat; } if (sgp == SGP_WRITE) folio_mark_accessed(folio); if (folio_test_uptodate(folio)) goto out; /* fallocated folio */ if (sgp != SGP_READ) goto clear; folio_unlock(folio); folio_put(folio); } /* * SGP_READ: succeed on hole, with NULL folio, letting caller zero. * SGP_NOALLOC: fail on hole, with NULL folio, letting caller fail. */ *foliop = NULL; if (sgp == SGP_READ) return 0; if (sgp == SGP_NOALLOC) return -ENOENT; /* * Fast cache lookup and swap lookup did not find it: allocate. */ if (vma && userfaultfd_missing(vma)) { *fault_type = handle_userfault(vmf, VM_UFFD_MISSING); return 0; } huge = shmem_is_huge(inode, index, false, fault_mm, vma ? vma->vm_flags : 0); /* Find hugepage orders that are allowed for anonymous shmem. */ if (vma && vma_is_anon_shmem(vma)) orders = shmem_allowable_huge_orders(inode, vma, index, huge); else if (huge) orders = BIT(HPAGE_PMD_ORDER); if (orders > 0) { gfp_t huge_gfp; huge_gfp = vma_thp_gfp_mask(vma); huge_gfp = limit_gfp_mask(huge_gfp, gfp); folio = shmem_alloc_and_add_folio(vmf, huge_gfp, inode, index, fault_mm, orders); if (!IS_ERR(folio)) { if (folio_test_pmd_mappable(folio)) count_vm_event(THP_FILE_ALLOC); #ifdef CONFIG_TRANSPARENT_HUGEPAGE count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_ALLOC); #endif goto alloced; } if (PTR_ERR(folio) == -EEXIST) goto repeat; } folio = shmem_alloc_and_add_folio(vmf, gfp, inode, index, fault_mm, 0); if (IS_ERR(folio)) { error = PTR_ERR(folio); if (error == -EEXIST) goto repeat; folio = NULL; goto unlock; } alloced: alloced = true; if (folio_test_large(folio) && DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < folio_next_index(folio) - 1) { struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); struct shmem_inode_info *info = SHMEM_I(inode); /* * Part of the large folio is beyond i_size: subject * to shrink under memory pressure. */ spin_lock(&sbinfo->shrinklist_lock); /* * _careful to defend against unlocked access to * ->shrink_list in shmem_unused_huge_shrink() */ if (list_empty_careful(&info->shrinklist)) { list_add_tail(&info->shrinklist, &sbinfo->shrinklist); sbinfo->shrinklist_len++; } spin_unlock(&sbinfo->shrinklist_lock); } if (sgp == SGP_WRITE) folio_set_referenced(folio); /* * Let SGP_FALLOC use the SGP_WRITE optimization on a new folio. */ if (sgp == SGP_FALLOC) sgp = SGP_WRITE; clear: /* * Let SGP_WRITE caller clear ends if write does not fill folio; * but SGP_FALLOC on a folio fallocated earlier must initialize * it now, lest undo on failure cancel our earlier guarantee. */ if (sgp != SGP_WRITE && !folio_test_uptodate(folio)) { long i, n = folio_nr_pages(folio); for (i = 0; i < n; i++) clear_highpage(folio_page(folio, i)); flush_dcache_folio(folio); folio_mark_uptodate(folio); } /* Perhaps the file has been truncated since we checked */ if (sgp <= SGP_CACHE && ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { error = -EINVAL; goto unlock; } out: *foliop = folio; return 0; /* * Error recovery. */ unlock: if (alloced) filemap_remove_folio(folio); shmem_recalc_inode(inode, 0, 0); if (folio) { folio_unlock(folio); folio_put(folio); } return error; } /** * shmem_get_folio - find, and lock a shmem folio. * @inode: inode to search * @index: the page index. * @foliop: pointer to the folio if found * @sgp: SGP_* flags to control behavior * * Looks up the page cache entry at @inode & @index. If a folio is * present, it is returned locked with an increased refcount. * * If the caller modifies data in the folio, it must call folio_mark_dirty() * before unlocking the folio to ensure that the folio is not reclaimed. * There is no need to reserve space before calling folio_mark_dirty(). * * When no folio is found, the behavior depends on @sgp: * - for SGP_READ, *@foliop is %NULL and 0 is returned * - for SGP_NOALLOC, *@foliop is %NULL and -ENOENT is returned * - for all other flags a new folio is allocated, inserted into the * page cache and returned locked in @foliop. * * Context: May sleep. * Return: 0 if successful, else a negative error code. */ int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop, enum sgp_type sgp) { return shmem_get_folio_gfp(inode, index, foliop, sgp, mapping_gfp_mask(inode->i_mapping), NULL, NULL); } EXPORT_SYMBOL_GPL(shmem_get_folio); /* * This is like autoremove_wake_function, but it removes the wait queue * entry unconditionally - even if something else had already woken the * target. */ static int synchronous_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) { int ret = default_wake_function(wait, mode, sync, key); list_del_init(&wait->entry); return ret; } /* * 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_rwsem. 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_rwsem in fault, * and bloating every shmem inode for this unlikely case would be sad. */ static vm_fault_t shmem_falloc_wait(struct vm_fault *vmf, struct inode *inode) { struct shmem_falloc *shmem_falloc; struct file *fpin = NULL; vm_fault_t ret = 0; 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; fpin = maybe_unlock_mmap_for_io(vmf, NULL); shmem_falloc_waitq = shmem_falloc->waitq; prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, TASK_UNINTERRUPTIBLE); spin_unlock(&inode->i_lock); schedule(); /* * shmem_falloc_waitq points into the shmem_fallocate() * stack of the hole-punching task: shmem_falloc_waitq * is usually invalid by the time we reach here, but * finish_wait() does not dereference it in that case; * though i_lock needed lest racing with wake_up_all(). */ spin_lock(&inode->i_lock); finish_wait(shmem_falloc_waitq, &shmem_fault_wait); } spin_unlock(&inode->i_lock); if (fpin) { fput(fpin); ret = VM_FAULT_RETRY; } return ret; } static vm_fault_t shmem_fault(struct vm_fault *vmf) { struct inode *inode = file_inode(vmf->vma->vm_file); gfp_t gfp = mapping_gfp_mask(inode->i_mapping); struct folio *folio = NULL; vm_fault_t ret = 0; int err; /* * Trinity finds that probing a hole which tmpfs is punching can * prevent the hole-punch from ever completing: noted in i_private. */ if (unlikely(inode->i_private)) { ret = shmem_falloc_wait(vmf, inode); if (ret) return ret; } WARN_ON_ONCE(vmf->page != NULL); err = shmem_get_folio_gfp(inode, vmf->pgoff, &folio, SGP_CACHE, gfp, vmf, &ret); if (err) return vmf_error(err); if (folio) { vmf->page = folio_file_page(folio, vmf->pgoff); ret |= VM_FAULT_LOCKED; } 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 addr; unsigned long offset; unsigned long inflated_len; unsigned long inflated_addr; unsigned long inflated_offset; unsigned long hpage_size; if (len > TASK_SIZE) return -ENOMEM; addr = mm_get_unmapped_area(current->mm, file, uaddr, len, pgoff, flags); if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) return addr; if (IS_ERR_VALUE(addr)) return addr; if (addr & ~PAGE_MASK) return addr; if (addr > TASK_SIZE - len) return addr; if (shmem_huge == SHMEM_HUGE_DENY) return addr; if (flags & MAP_FIXED) return addr; /* * Our priority is to support MAP_SHARED mapped hugely; * and support MAP_PRIVATE mapped hugely too, until it is COWed. * But if caller specified an address hint and we allocated area there * successfully, respect that as before. */ if (uaddr == addr) return addr; hpage_size = HPAGE_PMD_SIZE; if (shmem_huge != SHMEM_HUGE_FORCE) { struct super_block *sb; unsigned long __maybe_unused hpage_orders; int order = 0; 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; /* * Find the highest mTHP order used for anonymous shmem to * provide a suitable alignment address. */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE hpage_orders = READ_ONCE(huge_shmem_orders_always); hpage_orders |= READ_ONCE(huge_shmem_orders_within_size); hpage_orders |= READ_ONCE(huge_shmem_orders_madvise); if (SHMEM_SB(sb)->huge != SHMEM_HUGE_NEVER) hpage_orders |= READ_ONCE(huge_shmem_orders_inherit); if (hpage_orders > 0) { order = highest_order(hpage_orders); hpage_size = PAGE_SIZE << order; } #endif } if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER && !order) return addr; } if (len < hpage_size) return addr; offset = (pgoff << PAGE_SHIFT) & (hpage_size - 1); if (offset && offset + len < 2 * hpage_size) return addr; if ((addr & (hpage_size - 1)) == offset) return addr; inflated_len = len + hpage_size - PAGE_SIZE; if (inflated_len > TASK_SIZE) return addr; if (inflated_len < len) return addr; inflated_addr = mm_get_unmapped_area(current->mm, NULL, uaddr, inflated_len, 0, flags); if (IS_ERR_VALUE(inflated_addr)) return addr; if (inflated_addr & ~PAGE_MASK) return addr; inflated_offset = inflated_addr & (hpage_size - 1); inflated_addr += offset - inflated_offset; if (inflated_offset > offset) inflated_addr += hpage_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, pgoff_t *ilx) { struct inode *inode = file_inode(vma->vm_file); pgoff_t index; /* * Bias interleave by inode number to distribute better across nodes; * but this interface is independent of which page order is used, so * supplies only that bias, letting caller apply the offset (adjusted * by page order, as in shmem_get_pgoff_policy() and get_vma_policy()). */ *ilx = inode->i_ino; index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); } static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, pgoff_t index, unsigned int order, pgoff_t *ilx) { struct mempolicy *mpol; /* Bias interleave by inode number to distribute better across nodes */ *ilx = info->vfs_inode.i_ino + (index >> order); mpol = mpol_shared_policy_lookup(&info->policy, index); return mpol ? mpol : get_task_policy(current); } #else static struct mempolicy *shmem_get_pgoff_policy(struct shmem_inode_info *info, pgoff_t index, unsigned int order, pgoff_t *ilx) { *ilx = 0; return NULL; } #endif /* CONFIG_NUMA */ int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { struct inode *inode = file_inode(file); struct shmem_inode_info *info = SHMEM_I(inode); int retval = -ENOMEM; /* * What serializes the accesses to info->flags? * ipc_lock_object() when called from shmctl_do_lock(), * no serialization needed when called from shm_destroy(). */ if (lock && !(info->flags & VM_LOCKED)) { if (!user_shm_lock(inode->i_size, ucounts)) goto out_nomem; info->flags |= VM_LOCKED; mapping_set_unevictable(file->f_mapping); } if (!lock && (info->flags & VM_LOCKED) && ucounts) { user_shm_unlock(inode->i_size, ucounts); info->flags &= ~VM_LOCKED; mapping_clear_unevictable(file->f_mapping); } retval = 0; out_nomem: return retval; } static int shmem_mmap(struct file *file, struct vm_area_struct *vma) { struct inode *inode = file_inode(file); struct shmem_inode_info *info = SHMEM_I(inode); int ret; ret = seal_check_write(info->seals, vma); if (ret) return ret; /* arm64 - allow memory tagging on RAM-based files */ vm_flags_set(vma, VM_MTE_ALLOWED); file_accessed(file); /* This is anonymous shared memory if it is unlinked at the time of mmap */ if (inode->i_nlink) vma->vm_ops = &shmem_vm_ops; else vma->vm_ops = &shmem_anon_vm_ops; return 0; } static int shmem_file_open(struct inode *inode, struct file *file) { file->f_mode |= FMODE_CAN_ODIRECT; return generic_file_open(inode, file); } #ifdef CONFIG_TMPFS_XATTR static int shmem_initxattrs(struct inode *, const struct xattr *, void *); /* * chattr's fsflags are unrelated to extended attributes, * but tmpfs has chosen to enable them under the same config option. */ static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags) { unsigned int i_flags = 0; if (fsflags & FS_NOATIME_FL) i_flags |= S_NOATIME; if (fsflags & FS_APPEND_FL) i_flags |= S_APPEND; if (fsflags & FS_IMMUTABLE_FL) i_flags |= S_IMMUTABLE; /* * But FS_NODUMP_FL does not require any action in i_flags. */ inode_set_flags(inode, i_flags, S_NOATIME | S_APPEND | S_IMMUTABLE); } #else static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags) { } #define shmem_initxattrs NULL #endif static struct offset_ctx *shmem_get_offset_ctx(struct inode *inode) { return &SHMEM_I(inode)->dir_offsets; } static struct inode *__shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { struct inode *inode; struct shmem_inode_info *info; struct shmem_sb_info *sbinfo = SHMEM_SB(sb); ino_t ino; int err; err = shmem_reserve_inode(sb, &ino); if (err) return ERR_PTR(err); inode = new_inode(sb); if (!inode) { shmem_free_inode(sb, 0); return ERR_PTR(-ENOSPC); } inode->i_ino = ino; inode_init_owner(idmap, inode, dir, mode); inode->i_blocks = 0; simple_inode_init_ts(inode); inode->i_generation = get_random_u32(); info = SHMEM_I(inode); memset(info, 0, (char *)inode - (char *)info); spin_lock_init(&info->lock); atomic_set(&info->stop_eviction, 0); info->seals = F_SEAL_SEAL; info->flags = flags & VM_NORESERVE; info->i_crtime = inode_get_mtime(inode); info->fsflags = (dir == NULL) ? 0 : SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED; if (info->fsflags) shmem_set_inode_flags(inode, info->fsflags); INIT_LIST_HEAD(&info->shrinklist); INIT_LIST_HEAD(&info->swaplist); simple_xattrs_init(&info->xattrs); cache_no_acl(inode); if (sbinfo->noswap) mapping_set_unevictable(inode->i_mapping); mapping_set_large_folios(inode->i_mapping); 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_offset_dir_operations; simple_offset_init(shmem_get_offset_ctx(inode)); break; case S_IFLNK: /* * Must not load anything in the rbtree, * mpol_free_shared_policy will not be called. */ mpol_shared_policy_init(&info->policy, NULL); break; } lockdep_annotate_inode_mutex_key(inode); return inode; } #ifdef CONFIG_TMPFS_QUOTA static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { int err; struct inode *inode; inode = __shmem_get_inode(idmap, sb, dir, mode, dev, flags); if (IS_ERR(inode)) return inode; err = dquot_initialize(inode); if (err) goto errout; err = dquot_alloc_inode(inode); if (err) { dquot_drop(inode); goto errout; } return inode; errout: inode->i_flags |= S_NOQUOTA; iput(inode); return ERR_PTR(err); } #else static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { return __shmem_get_inode(idmap, sb, dir, mode, dev, flags); } #endif /* CONFIG_TMPFS_QUOTA */ #ifdef CONFIG_USERFAULTFD int shmem_mfill_atomic_pte(pmd_t *dst_pmd, struct vm_area_struct *dst_vma, unsigned long dst_addr, unsigned long src_addr, uffd_flags_t flags, struct folio **foliop) { struct inode *inode = file_inode(dst_vma->vm_file); struct shmem_inode_info *info = SHMEM_I(inode); struct address_space *mapping = inode->i_mapping; gfp_t gfp = mapping_gfp_mask(mapping); pgoff_t pgoff = linear_page_index(dst_vma, dst_addr); void *page_kaddr; struct folio *folio; int ret; pgoff_t max_off; if (shmem_inode_acct_blocks(inode, 1)) { /* * We may have got a page, returned -ENOENT triggering a retry, * and now we find ourselves with -ENOMEM. Release the page, to * avoid a BUG_ON in our caller. */ if (unlikely(*foliop)) { folio_put(*foliop); *foliop = NULL; } return -ENOMEM; } if (!*foliop) { ret = -ENOMEM; folio = shmem_alloc_folio(gfp, 0, info, pgoff); if (!folio) goto out_unacct_blocks; if (uffd_flags_mode_is(flags, MFILL_ATOMIC_COPY)) { page_kaddr = kmap_local_folio(folio, 0); /* * The read mmap_lock is held here. Despite the * mmap_lock being read recursive a deadlock is still * possible if a writer has taken a lock. For example: * * process A thread 1 takes read lock on own mmap_lock * process A thread 2 calls mmap, blocks taking write lock * process B thread 1 takes page fault, read lock on own mmap lock * process B thread 2 calls mmap, blocks taking write lock * process A thread 1 blocks taking read lock on process B * process B thread 1 blocks taking read lock on process A * * Disable page faults to prevent potential deadlock * and retry the copy outside the mmap_lock. */ pagefault_disable(); ret = copy_from_user(page_kaddr, (const void __user *)src_addr, PAGE_SIZE); pagefault_enable(); kunmap_local(page_kaddr); /* fallback to copy_from_user outside mmap_lock */ if (unlikely(ret)) { *foliop = folio; ret = -ENOENT; /* don't free the page */ goto out_unacct_blocks; } flush_dcache_folio(folio); } else { /* ZEROPAGE */ clear_user_highpage(&folio->page, dst_addr); } } else { folio = *foliop; VM_BUG_ON_FOLIO(folio_test_large(folio), folio); *foliop = NULL; } VM_BUG_ON(folio_test_locked(folio)); VM_BUG_ON(folio_test_swapbacked(folio)); __folio_set_locked(folio); __folio_set_swapbacked(folio); __folio_mark_uptodate(folio); ret = -EFAULT; max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); if (unlikely(pgoff >= max_off)) goto out_release; ret = mem_cgroup_charge(folio, dst_vma->vm_mm, gfp); if (ret) goto out_release; ret = shmem_add_to_page_cache(folio, mapping, pgoff, NULL, gfp); if (ret) goto out_release; ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr, &folio->page, true, flags); if (ret) goto out_delete_from_cache; shmem_recalc_inode(inode, 1, 0); folio_unlock(folio); return 0; out_delete_from_cache: filemap_remove_folio(folio); out_release: folio_unlock(folio); folio_put(folio); out_unacct_blocks: shmem_inode_unacct_blocks(inode, 1); return ret; } #endif /* CONFIG_USERFAULTFD */ #ifdef CONFIG_TMPFS static const struct inode_operations shmem_symlink_inode_operations; static const struct inode_operations shmem_short_symlink_operations; static int shmem_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, struct page **pagep, void **fsdata) { struct inode *inode = mapping->host; struct shmem_inode_info *info = SHMEM_I(inode); pgoff_t index = pos >> PAGE_SHIFT; struct folio *folio; int ret = 0; /* i_rwsem is held by caller */ if (unlikely(info->seals & (F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_FUTURE_WRITE))) { if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) return -EPERM; if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size) return -EPERM; } ret = shmem_get_folio(inode, index, &folio, SGP_WRITE); if (ret) return ret; *pagep = folio_file_page(folio, index); if (PageHWPoison(*pagep)) { folio_unlock(folio); folio_put(folio); *pagep = NULL; return -EIO; } return 0; } 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 folio *folio = page_folio(page); struct inode *inode = mapping->host; if (pos + copied > inode->i_size) i_size_write(inode, pos + copied); if (!folio_test_uptodate(folio)) { if (copied < folio_size(folio)) { size_t from = offset_in_folio(folio, pos); folio_zero_segments(folio, 0, from, from + copied, folio_size(folio)); } folio_mark_uptodate(folio); } folio_mark_dirty(folio); folio_unlock(folio); folio_put(folio); 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; int error = 0; ssize_t retval = 0; loff_t *ppos = &iocb->ki_pos; index = *ppos >> PAGE_SHIFT; offset = *ppos & ~PAGE_MASK; for (;;) { struct folio *folio = NULL; 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_get_folio(inode, index, &folio, SGP_READ); if (error) { if (error == -EINVAL) error = 0; break; } if (folio) { folio_unlock(folio); page = folio_file_page(folio, index); if (PageHWPoison(page)) { folio_put(folio); error = -EIO; break; } } /* * We must evaluate after, since reads (unlike writes) * are called without i_rwsem 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 (folio) folio_put(folio); break; } } nr -= offset; if (folio) { /* * 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) folio_mark_accessed(folio); /* * 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); folio_put(folio); } else if (user_backed_iter(to)) { /* * Copy to user tends to be so well optimized, but * clear_user() not so much, that it is noticeably * faster to copy the zero page instead of clearing. */ ret = copy_page_to_iter(ZERO_PAGE(0), offset, nr, to); } else { /* * But submitting the same page twice in a row to * splice() - or others? - can result in confusion: * so don't attempt that optimization on pipes etc. */ ret = iov_iter_zero(nr, to); } retval += ret; offset += ret; index += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK; if (!iov_iter_count(to)) break; if (ret < nr) { error = -EFAULT; break; } cond_resched(); } *ppos = ((loff_t) index << PAGE_SHIFT) + offset; file_accessed(file); return retval ? retval : error; } static ssize_t shmem_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; ssize_t ret; inode_lock(inode); ret = generic_write_checks(iocb, from); if (ret <= 0) goto unlock; ret = file_remove_privs(file); if (ret) goto unlock; ret = file_update_time(file); if (ret) goto unlock; ret = generic_perform_write(iocb, from); unlock: inode_unlock(inode); return ret; } static bool zero_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { return true; } static void zero_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { } static bool zero_pipe_buf_try_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { return false; } static const struct pipe_buf_operations zero_pipe_buf_ops = { .release = zero_pipe_buf_release, .try_steal = zero_pipe_buf_try_steal, .get = zero_pipe_buf_get, }; static size_t splice_zeropage_into_pipe(struct pipe_inode_info *pipe, loff_t fpos, size_t size) { size_t offset = fpos & ~PAGE_MASK; size = min_t(size_t, size, PAGE_SIZE - offset); if (!pipe_full(pipe->head, pipe->tail, pipe->max_usage)) { struct pipe_buffer *buf = pipe_head_buf(pipe); *buf = (struct pipe_buffer) { .ops = &zero_pipe_buf_ops, .page = ZERO_PAGE(0), .offset = offset, .len = size, }; pipe->head++; } return size; } static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe, size_t len, unsigned int flags) { struct inode *inode = file_inode(in); struct address_space *mapping = inode->i_mapping; struct folio *folio = NULL; size_t total_spliced = 0, used, npages, n, part; loff_t isize; int error = 0; /* Work out how much data we can actually add into the pipe */ used = pipe_occupancy(pipe->head, pipe->tail); npages = max_t(ssize_t, pipe->max_usage - used, 0); len = min_t(size_t, len, npages * PAGE_SIZE); do { if (*ppos >= i_size_read(inode)) break; error = shmem_get_folio(inode, *ppos / PAGE_SIZE, &folio, SGP_READ); if (error) { if (error == -EINVAL) error = 0; break; } if (folio) { folio_unlock(folio); if (folio_test_hwpoison(folio) || (folio_test_large(folio) && folio_test_has_hwpoisoned(folio))) { error = -EIO; break; } } /* * i_size must be checked after we know the pages are Uptodate. * * Checking i_size after the check allows us to calculate * the correct value for "nr", which means the zero-filled * part of the page is not copied back to userspace (unless * another truncate extends the file - this is desired though). */ isize = i_size_read(inode); if (unlikely(*ppos >= isize)) break; part = min_t(loff_t, isize - *ppos, len); if (folio) { /* * 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_folio(folio); folio_mark_accessed(folio); /* * Ok, we have the page, and it's up-to-date, so we can * now splice it into the pipe. */ n = splice_folio_into_pipe(pipe, folio, *ppos, part); folio_put(folio); folio = NULL; } else { n = splice_zeropage_into_pipe(pipe, *ppos, part); } if (!n) break; len -= n; total_spliced += n; *ppos += n; in->f_ra.prev_pos = *ppos; if (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) break; cond_resched(); } while (len); if (folio) folio_put(folio); file_accessed(in); return total_spliced ? total_spliced : error; } static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) { struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; if (whence != SEEK_DATA && whence != SEEK_HOLE) return generic_file_llseek_size(file, offset, whence, MAX_LFS_FILESIZE, i_size_read(inode)); if (offset < 0) return -ENXIO; inode_lock(inode); /* We're holding i_rwsem so we can access i_size directly */ offset = mapping_seek_hole_data(mapping, offset, inode->i_size, whence); if (offset >= 0) offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); inode_unlock(inode); return offset; } static long shmem_fallocate(struct file *file, int mode, loff_t offset, loff_t len) { struct inode *inode = file_inode(file); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); struct shmem_inode_info *info = SHMEM_I(inode); struct shmem_falloc shmem_falloc; pgoff_t start, index, end, undo_fallocend; 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_rwsem */ if (info->seals & (F_SEAL_WRITE | F_SEAL_FUTURE_WRITE)) { error = -EPERM; goto out; } shmem_falloc.waitq = &shmem_falloc_waitq; shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT; shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; spin_lock(&inode->i_lock); inode->i_private = &shmem_falloc; spin_unlock(&inode->i_lock); if ((u64)unmap_end > (u64)unmap_start) unmap_mapping_range(mapping, unmap_start, 1 + unmap_end - unmap_start, 0); shmem_truncate_range(inode, offset, offset + len - 1); /* No need to unmap again: hole-punching leaves COWed pages */ spin_lock(&inode->i_lock); inode->i_private = NULL; wake_up_all(&shmem_falloc_waitq); WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.head)); spin_unlock(&inode->i_lock); error = 0; goto out; } /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ error = inode_newsize_ok(inode, offset + len); if (error) goto out; if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { error = -EPERM; goto out; } start = offset >> PAGE_SHIFT; end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT; /* Try to avoid a swapstorm if len is impossible to satisfy */ if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { error = -ENOSPC; goto out; } shmem_falloc.waitq = NULL; shmem_falloc.start = start; shmem_falloc.next = start; shmem_falloc.nr_falloced = 0; shmem_falloc.nr_unswapped = 0; spin_lock(&inode->i_lock); inode->i_private = &shmem_falloc; spin_unlock(&inode->i_lock); /* * info->fallocend is only relevant when huge pages might be * involved: to prevent split_huge_page() freeing fallocated * pages when FALLOC_FL_KEEP_SIZE committed beyond i_size. */ undo_fallocend = info->fallocend; if (info->fallocend < end) info->fallocend = end; for (index = start; index < end; ) { struct folio *folio; /* * Check for fatal signal so that we abort early in OOM * situations. We don't want to abort in case of non-fatal * signals as large fallocate can take noticeable time and * e.g. periodic timers may result in fallocate constantly * restarting. */ if (fatal_signal_pending(current)) error = -EINTR; else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) error = -ENOMEM; else error = shmem_get_folio(inode, index, &folio, SGP_FALLOC); if (error) { info->fallocend = undo_fallocend; /* Remove the !uptodate folios we added */ if (index > start) { shmem_undo_range(inode, (loff_t)start << PAGE_SHIFT, ((loff_t)index << PAGE_SHIFT) - 1, true); } goto undone; } /* * Here is a more important optimization than it appears: * a second SGP_FALLOC on the same large folio will clear it, * making it uptodate and un-undoable if we fail later. */ index = folio_next_index(folio); /* Beware 32-bit wraparound */ if (!index) index--; /* * Inform shmem_writepage() how far we have reached. * No need for lock or barrier: we have the page lock. */ if (!folio_test_uptodate(folio)) shmem_falloc.nr_falloced += index - shmem_falloc.next; shmem_falloc.next = index; /* * If !uptodate, leave it that way so that freeable folios * can be recognized if we need to rollback on error later. * But mark it dirty so that memory pressure will swap rather * than free the folios we are allocating (and SGP_CACHE folios * might still be clean: we now need to mark those dirty too). */ folio_mark_dirty(folio); folio_unlock(folio); folio_put(folio); cond_resched(); } if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) i_size_write(inode, offset + len); undone: spin_lock(&inode->i_lock); inode->i_private = NULL; spin_unlock(&inode->i_lock); out: if (!error) file_modified(file); 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_ispace / BOGO_INODE_SIZE; } /* else leave those fields 0 like simple_statfs */ buf->f_fsid = uuid_to_fsid(dentry->d_sb->s_uuid.b); return 0; } /* * File creation. Allocate an inode, and we're done.. */ static int shmem_mknod(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) { struct inode *inode; int error; inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, VM_NORESERVE); if (IS_ERR(inode)) return PTR_ERR(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 = simple_offset_add(shmem_get_offset_ctx(dir), dentry); if (error) goto out_iput; dir->i_size += BOGO_DIRENT_SIZE; inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); inode_inc_iversion(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 mnt_idmap *idmap, struct inode *dir, struct file *file, umode_t mode) { struct inode *inode; int error; inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, 0, VM_NORESERVE); if (IS_ERR(inode)) { error = PTR_ERR(inode); goto err_out; } 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(file, inode); err_out: return finish_open_simple(file, error); out_iput: iput(inode); return error; } static int shmem_mkdir(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, umode_t mode) { int error; error = shmem_mknod(idmap, dir, dentry, mode | S_IFDIR, 0); if (error) return error; inc_nlink(dir); return 0; } static int shmem_create(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { return shmem_mknod(idmap, dir, dentry, mode | S_IFREG, 0); } /* * Link a file.. */ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) { struct inode *inode = d_inode(old_dentry); int ret = 0; /* * No ordinary (disk based) filesystem counts links as inodes; * but each new link needs a new dentry, pinning lowmem, and * tmpfs dentries cannot be pruned until they are unlinked. * But if an O_TMPFILE file is linked into the tmpfs, the * first link must skip that, to get the accounting right. */ if (inode->i_nlink) { ret = shmem_reserve_inode(inode->i_sb, NULL); if (ret) goto out; } ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry); if (ret) { if (inode->i_nlink) shmem_free_inode(inode->i_sb, 0); goto out; } dir->i_size += BOGO_DIRENT_SIZE; inode_set_mtime_to_ts(dir, inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); inode_inc_iversion(dir); 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, 0); simple_offset_remove(shmem_get_offset_ctx(dir), dentry); dir->i_size -= BOGO_DIRENT_SIZE; inode_set_mtime_to_ts(dir, inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode))); inode_inc_iversion(dir); drop_nlink(inode); dput(dentry); /* Undo the count from "create" - does all the work */ return 0; } static int shmem_rmdir(struct inode *dir, struct dentry *dentry) { if (!simple_offset_empty(dentry)) return -ENOTEMPTY; drop_nlink(d_inode(dentry)); drop_nlink(dir); return shmem_unlink(dir, dentry); } static int shmem_whiteout(struct mnt_idmap *idmap, 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(idmap, 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 mnt_idmap *idmap, 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); int error; if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) return -EINVAL; if (flags & RENAME_EXCHANGE) return simple_offset_rename_exchange(old_dir, old_dentry, new_dir, new_dentry); if (!simple_offset_empty(new_dentry)) return -ENOTEMPTY; if (flags & RENAME_WHITEOUT) { error = shmem_whiteout(idmap, old_dir, old_dentry); if (error) return error; } error = simple_offset_rename(old_dir, old_dentry, new_dir, new_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; simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry); inode_inc_iversion(old_dir); inode_inc_iversion(new_dir); return 0; } static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, struct dentry *dentry, const char *symname) { int error; int len; struct inode *inode; struct folio *folio; len = strlen(symname) + 1; if (len > PAGE_SIZE) return -ENAMETOOLONG; inode = shmem_get_inode(idmap, dir->i_sb, dir, S_IFLNK | 0777, 0, VM_NORESERVE); if (IS_ERR(inode)) return PTR_ERR(inode); error = security_inode_init_security(inode, dir, &dentry->d_name, shmem_initxattrs, NULL); if (error && error != -EOPNOTSUPP) goto out_iput; error = simple_offset_add(shmem_get_offset_ctx(dir), dentry); if (error) goto out_iput; inode->i_size = len-1; if (len <= SHORT_SYMLINK_LEN) { inode->i_link = kmemdup(symname, len, GFP_KERNEL); if (!inode->i_link) { error = -ENOMEM; goto out_remove_offset; } inode->i_op = &shmem_short_symlink_operations; } else { inode_nohighmem(inode); inode->i_mapping->a_ops = &shmem_aops; error = shmem_get_folio(inode, 0, &folio, SGP_WRITE); if (error) goto out_remove_offset; inode->i_op = &shmem_symlink_inode_operations; memcpy(folio_address(folio), symname, len); folio_mark_uptodate(folio); folio_mark_dirty(folio); folio_unlock(folio); folio_put(folio); } dir->i_size += BOGO_DIRENT_SIZE; inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir)); inode_inc_iversion(dir); d_instantiate(dentry, inode); dget(dentry); return 0; out_remove_offset: simple_offset_remove(shmem_get_offset_ctx(dir), dentry); out_iput: iput(inode); return error; } static void shmem_put_link(void *arg) { folio_mark_accessed(arg); folio_put(arg); } static const char *shmem_get_link(struct dentry *dentry, struct inode *inode, struct delayed_call *done) { struct folio *folio = NULL; int error; if (!dentry) { folio = filemap_get_folio(inode->i_mapping, 0); if (IS_ERR(folio)) return ERR_PTR(-ECHILD); if (PageHWPoison(folio_page(folio, 0)) || !folio_test_uptodate(folio)) { folio_put(folio); return ERR_PTR(-ECHILD); } } else { error = shmem_get_folio(inode, 0, &folio, SGP_READ); if (error) return ERR_PTR(error); if (!folio) return ERR_PTR(-ECHILD); if (PageHWPoison(folio_page(folio, 0))) { folio_unlock(folio); folio_put(folio); return ERR_PTR(-ECHILD); } folio_unlock(folio); } set_delayed_call(done, shmem_put_link, folio); return folio_address(folio); } #ifdef CONFIG_TMPFS_XATTR static int shmem_fileattr_get(struct dentry *dentry, struct fileattr *fa) { struct shmem_inode_info *info = SHMEM_I(d_inode(dentry)); fileattr_fill_flags(fa, info->fsflags & SHMEM_FL_USER_VISIBLE); return 0; } static int shmem_fileattr_set(struct mnt_idmap *idmap, struct dentry *dentry, struct fileattr *fa) { struct inode *inode = d_inode(dentry); struct shmem_inode_info *info = SHMEM_I(inode); if (fileattr_has_fsx(fa)) return -EOPNOTSUPP; if (fa->flags & ~SHMEM_FL_USER_MODIFIABLE) return -EOPNOTSUPP; info->fsflags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) | (fa->flags & SHMEM_FL_USER_MODIFIABLE); shmem_set_inode_flags(inode, info->fsflags); inode_set_ctime_current(inode); inode_inc_iversion(inode); return 0; } /* * 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); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); const struct xattr *xattr; struct simple_xattr *new_xattr; size_t ispace = 0; size_t len; if (sbinfo->max_inodes) { for (xattr = xattr_array; xattr->name != NULL; xattr++) { ispace += simple_xattr_space(xattr->name, xattr->value_len + XATTR_SECURITY_PREFIX_LEN); } if (ispace) { raw_spin_lock(&sbinfo->stat_lock); if (sbinfo->free_ispace < ispace) ispace = 0; else sbinfo->free_ispace -= ispace; raw_spin_unlock(&sbinfo->stat_lock); if (!ispace) return -ENOSPC; } } for (xattr = xattr_array; xattr->name != NULL; xattr++) { new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); if (!new_xattr) break; len = strlen(xattr->name) + 1; new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, GFP_KERNEL_ACCOUNT); if (!new_xattr->name) { kvfree(new_xattr); break; } memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, xattr->name, len); simple_xattr_add(&info->xattrs, new_xattr); } if (xattr->name != NULL) { if (ispace) { raw_spin_lock(&sbinfo->stat_lock); sbinfo->free_ispace += ispace; raw_spin_unlock(&sbinfo->stat_lock); } simple_xattrs_free(&info->xattrs, NULL); return -ENOMEM; } 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 mnt_idmap *idmap, 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); struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); struct simple_xattr *old_xattr; size_t ispace = 0; name = xattr_full_name(handler, name); if (value && sbinfo->max_inodes) { ispace = simple_xattr_space(name, size); raw_spin_lock(&sbinfo->stat_lock); if (sbinfo->free_ispace < ispace) ispace = 0; else sbinfo->free_ispace -= ispace; raw_spin_unlock(&sbinfo->stat_lock); if (!ispace) return -ENOSPC; } old_xattr = simple_xattr_set(&info->xattrs, name, value, size, flags); if (!IS_ERR(old_xattr)) { ispace = 0; if (old_xattr && sbinfo->max_inodes) ispace = simple_xattr_space(old_xattr->name, old_xattr->size); simple_xattr_free(old_xattr); old_xattr = NULL; inode_set_ctime_current(inode); inode_inc_iversion(inode); } if (ispace) { raw_spin_lock(&sbinfo->stat_lock); sbinfo->free_ispace += ispace; raw_spin_unlock(&sbinfo->stat_lock); } return PTR_ERR(old_xattr); } 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_user_xattr_handler = { .prefix = XATTR_USER_PREFIX, .get = shmem_xattr_handler_get, .set = shmem_xattr_handler_set, }; static const struct xattr_handler * const shmem_xattr_handlers[] = { &shmem_security_xattr_handler, &shmem_trusted_xattr_handler, &shmem_user_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 = { .getattr = shmem_getattr, .setattr = shmem_setattr, .get_link = simple_get_link, #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, #endif }; static const struct inode_operations shmem_symlink_inode_operations = { .getattr = shmem_getattr, .setattr = shmem_setattr, .get_link = shmem_get_link, #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, #endif }; static struct dentry *shmem_get_parent(struct dentry *child) { return ERR_PTR(-ESTALE); } static int shmem_match(struct inode *ino, void *vfh) { __u32 *fh = vfh; __u64 inum = fh[2]; inum = (inum << 32) | fh[1]; return ino->i_ino == inum && fh[0] == ino->i_generation; } /* Find any alias of inode, but prefer a hashed alias */ static struct dentry *shmem_find_alias(struct inode *inode) { struct dentry *alias = d_find_alias(inode); return alias ?: d_find_any_alias(inode); } static struct dentry *shmem_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type) { struct inode *inode; struct dentry *dentry = NULL; u64 inum; if (fh_len < 3) return NULL; inum = fid->raw[2]; inum = (inum << 32) | fid->raw[1]; inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), shmem_match, fid->raw); if (inode) { dentry = shmem_find_alias(inode); iput(inode); } return dentry; } static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, struct inode *parent) { if (*len < 3) { *len = 3; return FILEID_INVALID; } if (inode_unhashed(inode)) { /* Unfortunately insert_inode_hash is not idempotent, * so as we hash inodes here rather than at creation * time, we need a lock to ensure we only try * to do it once */ static DEFINE_SPINLOCK(lock); spin_lock(&lock); if (inode_unhashed(inode)) __insert_inode_hash(inode, inode->i_ino + inode->i_generation); spin_unlock(&lock); } fh[0] = inode->i_generation; fh[1] = inode->i_ino; fh[2] = ((__u64)inode->i_ino) >> 32; *len = 3; return 1; } static const struct export_operations shmem_export_ops = { .get_parent = shmem_get_parent, .encode_fh = shmem_encode_fh, .fh_to_dentry = shmem_fh_to_dentry, }; enum shmem_param { Opt_gid, Opt_huge, Opt_mode, Opt_mpol, Opt_nr_blocks, Opt_nr_inodes, Opt_size, Opt_uid, Opt_inode32, Opt_inode64, Opt_noswap, Opt_quota, Opt_usrquota, Opt_grpquota, Opt_usrquota_block_hardlimit, Opt_usrquota_inode_hardlimit, Opt_grpquota_block_hardlimit, Opt_grpquota_inode_hardlimit, }; static const struct constant_table shmem_param_enums_huge[] = { {"never", SHMEM_HUGE_NEVER }, {"always", SHMEM_HUGE_ALWAYS }, {"within_size", SHMEM_HUGE_WITHIN_SIZE }, {"advise", SHMEM_HUGE_ADVISE }, {} }; const struct fs_parameter_spec shmem_fs_parameters[] = { fsparam_gid ("gid", Opt_gid), fsparam_enum ("huge", Opt_huge, shmem_param_enums_huge), fsparam_u32oct("mode", Opt_mode), fsparam_string("mpol", Opt_mpol), fsparam_string("nr_blocks", Opt_nr_blocks), fsparam_string("nr_inodes", Opt_nr_inodes), fsparam_string("size", Opt_size), fsparam_uid ("uid", Opt_uid), fsparam_flag ("inode32", Opt_inode32), fsparam_flag ("inode64", Opt_inode64), fsparam_flag ("noswap", Opt_noswap), #ifdef CONFIG_TMPFS_QUOTA fsparam_flag ("quota", Opt_quota), fsparam_flag ("usrquota", Opt_usrquota), fsparam_flag ("grpquota", Opt_grpquota), fsparam_string("usrquota_block_hardlimit", Opt_usrquota_block_hardlimit), fsparam_string("usrquota_inode_hardlimit", Opt_usrquota_inode_hardlimit), fsparam_string("grpquota_block_hardlimit", Opt_grpquota_block_hardlimit), fsparam_string("grpquota_inode_hardlimit", Opt_grpquota_inode_hardlimit), #endif {} }; static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param) { struct shmem_options *ctx = fc->fs_private; struct fs_parse_result result; unsigned long long size; char *rest; int opt; kuid_t kuid; kgid_t kgid; opt = fs_parse(fc, shmem_fs_parameters, param, &result); if (opt < 0) return opt; switch (opt) { case Opt_size: size = memparse(param->string, &rest); if (*rest == '%') { size <<= PAGE_SHIFT; size *= totalram_pages(); do_div(size, 100); rest++; } if (*rest) goto bad_value; ctx->blocks = DIV_ROUND_UP(size, PAGE_SIZE); ctx->seen |= SHMEM_SEEN_BLOCKS; break; case Opt_nr_blocks: ctx->blocks = memparse(param->string, &rest); if (*rest || ctx->blocks > LONG_MAX) goto bad_value; ctx->seen |= SHMEM_SEEN_BLOCKS; break; case Opt_nr_inodes: ctx->inodes = memparse(param->string, &rest); if (*rest || ctx->inodes > ULONG_MAX / BOGO_INODE_SIZE) goto bad_value; ctx->seen |= SHMEM_SEEN_INODES; break; case Opt_mode: ctx->mode = result.uint_32 & 07777; break; case Opt_uid: kuid = result.uid; /* * The requested uid must be representable in the * filesystem's idmapping. */ if (!kuid_has_mapping(fc->user_ns, kuid)) goto bad_value; ctx->uid = kuid; break; case Opt_gid: kgid = result.gid; /* * The requested gid must be representable in the * filesystem's idmapping. */ if (!kgid_has_mapping(fc->user_ns, kgid)) goto bad_value; ctx->gid = kgid; break; case Opt_huge: ctx->huge = result.uint_32; if (ctx->huge != SHMEM_HUGE_NEVER && !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && has_transparent_hugepage())) goto unsupported_parameter; ctx->seen |= SHMEM_SEEN_HUGE; break; case Opt_mpol: if (IS_ENABLED(CONFIG_NUMA)) { mpol_put(ctx->mpol); ctx->mpol = NULL; if (mpol_parse_str(param->string, &ctx->mpol)) goto bad_value; break; } goto unsupported_parameter; case Opt_inode32: ctx->full_inums = false; ctx->seen |= SHMEM_SEEN_INUMS; break; case Opt_inode64: if (sizeof(ino_t) < 8) { return invalfc(fc, "Cannot use inode64 with <64bit inums in kernel\n"); } ctx->full_inums = true; ctx->seen |= SHMEM_SEEN_INUMS; break; case Opt_noswap: if ((fc->user_ns != &init_user_ns) || !capable(CAP_SYS_ADMIN)) { return invalfc(fc, "Turning off swap in unprivileged tmpfs mounts unsupported"); } ctx->noswap = true; ctx->seen |= SHMEM_SEEN_NOSWAP; break; case Opt_quota: if (fc->user_ns != &init_user_ns) return invalfc(fc, "Quotas in unprivileged tmpfs mounts are unsupported"); ctx->seen |= SHMEM_SEEN_QUOTA; ctx->quota_types |= (QTYPE_MASK_USR | QTYPE_MASK_GRP); break; case Opt_usrquota: if (fc->user_ns != &init_user_ns) return invalfc(fc, "Quotas in unprivileged tmpfs mounts are unsupported"); ctx->seen |= SHMEM_SEEN_QUOTA; ctx->quota_types |= QTYPE_MASK_USR; break; case Opt_grpquota: if (fc->user_ns != &init_user_ns) return invalfc(fc, "Quotas in unprivileged tmpfs mounts are unsupported"); ctx->seen |= SHMEM_SEEN_QUOTA; ctx->quota_types |= QTYPE_MASK_GRP; break; case Opt_usrquota_block_hardlimit: size = memparse(param->string, &rest); if (*rest || !size) goto bad_value; if (size > SHMEM_QUOTA_MAX_SPC_LIMIT) return invalfc(fc, "User quota block hardlimit too large."); ctx->qlimits.usrquota_bhardlimit = size; break; case Opt_grpquota_block_hardlimit: size = memparse(param->string, &rest); if (*rest || !size) goto bad_value; if (size > SHMEM_QUOTA_MAX_SPC_LIMIT) return invalfc(fc, "Group quota block hardlimit too large."); ctx->qlimits.grpquota_bhardlimit = size; break; case Opt_usrquota_inode_hardlimit: size = memparse(param->string, &rest); if (*rest || !size) goto bad_value; if (size > SHMEM_QUOTA_MAX_INO_LIMIT) return invalfc(fc, "User quota inode hardlimit too large."); ctx->qlimits.usrquota_ihardlimit = size; break; case Opt_grpquota_inode_hardlimit: size = memparse(param->string, &rest); if (*rest || !size) goto bad_value; if (size > SHMEM_QUOTA_MAX_INO_LIMIT) return invalfc(fc, "Group quota inode hardlimit too large."); ctx->qlimits.grpquota_ihardlimit = size; break; } return 0; unsupported_parameter: return invalfc(fc, "Unsupported parameter '%s'", param->key); bad_value: return invalfc(fc, "Bad value for '%s'", param->key); } static int shmem_parse_options(struct fs_context *fc, void *data) { char *options = data; if (options) { int err = security_sb_eat_lsm_opts(options, &fc->security); if (err) return err; } while (options != NULL) { char *this_char = options; for (;;) { /* * NUL-terminate this option: unfortunately, * mount options form a comma-separated list, * but mpol's nodelist may also contain commas. */ options = strchr(options, ','); if (options == NULL) break; options++; if (!isdigit(*options)) { options[-1] = '\0'; break; } } if (*this_char) { char *value = strchr(this_char, '='); size_t len = 0; int err; if (value) { *value++ = '\0'; len = strlen(value); } err = vfs_parse_fs_string(fc, this_char, value, len); if (err < 0) return err; } } return 0; } /* * Reconfigure a shmem filesystem. */ static int shmem_reconfigure(struct fs_context *fc) { struct shmem_options *ctx = fc->fs_private; struct shmem_sb_info *sbinfo = SHMEM_SB(fc->root->d_sb); unsigned long used_isp; struct mempolicy *mpol = NULL; const char *err; raw_spin_lock(&sbinfo->stat_lock); used_isp = sbinfo->max_inodes * BOGO_INODE_SIZE - sbinfo->free_ispace; if ((ctx->seen & SHMEM_SEEN_BLOCKS) && ctx->blocks) { if (!sbinfo->max_blocks) { err = "Cannot retroactively limit size"; goto out; } if (percpu_counter_compare(&sbinfo->used_blocks, ctx->blocks) > 0) { err = "Too small a size for current use"; goto out; } } if ((ctx->seen & SHMEM_SEEN_INODES) && ctx->inodes) { if (!sbinfo->max_inodes) { err = "Cannot retroactively limit inodes"; goto out; } if (ctx->inodes * BOGO_INODE_SIZE < used_isp) { err = "Too few inodes for current use"; goto out; } } if ((ctx->seen & SHMEM_SEEN_INUMS) && !ctx->full_inums && sbinfo->next_ino > UINT_MAX) { err = "Current inum too high to switch to 32-bit inums"; goto out; } if ((ctx->seen & SHMEM_SEEN_NOSWAP) && ctx->noswap && !sbinfo->noswap) { err = "Cannot disable swap on remount"; goto out; } if (!(ctx->seen & SHMEM_SEEN_NOSWAP) && !ctx->noswap && sbinfo->noswap) { err = "Cannot enable swap on remount if it was disabled on first mount"; goto out; } if (ctx->seen & SHMEM_SEEN_QUOTA && !sb_any_quota_loaded(fc->root->d_sb)) { err = "Cannot enable quota on remount"; goto out; } #ifdef CONFIG_TMPFS_QUOTA #define CHANGED_LIMIT(name) \ (ctx->qlimits.name## hardlimit && \ (ctx->qlimits.name## hardlimit != sbinfo->qlimits.name## hardlimit)) if (CHANGED_LIMIT(usrquota_b) || CHANGED_LIMIT(usrquota_i) || CHANGED_LIMIT(grpquota_b) || CHANGED_LIMIT(grpquota_i)) { err = "Cannot change global quota limit on remount"; goto out; } #endif /* CONFIG_TMPFS_QUOTA */ if (ctx->seen & SHMEM_SEEN_HUGE) sbinfo->huge = ctx->huge; if (ctx->seen & SHMEM_SEEN_INUMS) sbinfo->full_inums = ctx->full_inums; if (ctx->seen & SHMEM_SEEN_BLOCKS) sbinfo->max_blocks = ctx->blocks; if (ctx->seen & SHMEM_SEEN_INODES) { sbinfo->max_inodes = ctx->inodes; sbinfo->free_ispace = ctx->inodes * BOGO_INODE_SIZE - used_isp; } /* * Preserve previous mempolicy unless mpol remount option was specified. */ if (ctx->mpol) { mpol = sbinfo->mpol; sbinfo->mpol = ctx->mpol; /* transfers initial ref */ ctx->mpol = NULL; } if (ctx->noswap) sbinfo->noswap = true; raw_spin_unlock(&sbinfo->stat_lock); mpol_put(mpol); return 0; out: raw_spin_unlock(&sbinfo->stat_lock); return invalfc(fc, "%s", err); } static int shmem_show_options(struct seq_file *seq, struct dentry *root) { struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); struct mempolicy *mpol; if (sbinfo->max_blocks != shmem_default_max_blocks()) seq_printf(seq, ",size=%luk", K(sbinfo->max_blocks)); if (sbinfo->max_inodes != shmem_default_max_inodes()) seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); if (sbinfo->mode != (0777 | S_ISVTX)) seq_printf(seq, ",mode=%03ho", sbinfo->mode); if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) seq_printf(seq, ",uid=%u", from_kuid_munged(&init_user_ns, sbinfo->uid)); if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, sbinfo->gid)); /* * Showing inode{64,32} might be useful even if it's the system default, * since then people don't have to resort to checking both here and * /proc/config.gz to confirm 64-bit inums were successfully applied * (which may not even exist if IKCONFIG_PROC isn't enabled). * * We hide it when inode64 isn't the default and we are using 32-bit * inodes, since that probably just means the feature isn't even under * consideration. * * As such: * * +-----------------+-----------------+ * | TMPFS_INODE64=y | TMPFS_INODE64=n | * +------------------+-----------------+-----------------+ * | full_inums=true | show | show | * | full_inums=false | show | hide | * +------------------+-----------------+-----------------+ * */ if (IS_ENABLED(CONFIG_TMPFS_INODE64) || sbinfo->full_inums) seq_printf(seq, ",inode%d", (sbinfo->full_inums ? 64 : 32)); #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */ if (sbinfo->huge) seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge)); #endif mpol = shmem_get_sbmpol(sbinfo); shmem_show_mpol(seq, mpol); mpol_put(mpol); if (sbinfo->noswap) seq_printf(seq, ",noswap"); #ifdef CONFIG_TMPFS_QUOTA if (sb_has_quota_active(root->d_sb, USRQUOTA)) seq_printf(seq, ",usrquota"); if (sb_has_quota_active(root->d_sb, GRPQUOTA)) seq_printf(seq, ",grpquota"); if (sbinfo->qlimits.usrquota_bhardlimit) seq_printf(seq, ",usrquota_block_hardlimit=%lld", sbinfo->qlimits.usrquota_bhardlimit); if (sbinfo->qlimits.grpquota_bhardlimit) seq_printf(seq, ",grpquota_block_hardlimit=%lld", sbinfo->qlimits.grpquota_bhardlimit); if (sbinfo->qlimits.usrquota_ihardlimit) seq_printf(seq, ",usrquota_inode_hardlimit=%lld", sbinfo->qlimits.usrquota_ihardlimit); if (sbinfo->qlimits.grpquota_ihardlimit) seq_printf(seq, ",grpquota_inode_hardlimit=%lld", sbinfo->qlimits.grpquota_ihardlimit); #endif return 0; } #endif /* CONFIG_TMPFS */ static void shmem_put_super(struct super_block *sb) { struct shmem_sb_info *sbinfo = SHMEM_SB(sb); #ifdef CONFIG_TMPFS_QUOTA shmem_disable_quotas(sb); #endif free_percpu(sbinfo->ino_batch); percpu_counter_destroy(&sbinfo->used_blocks); mpol_put(sbinfo->mpol); kfree(sbinfo); sb->s_fs_info = NULL; } static int shmem_fill_super(struct super_block *sb, struct fs_context *fc) { struct shmem_options *ctx = fc->fs_private; struct inode *inode; struct shmem_sb_info *sbinfo; int error = -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 error; sb->s_fs_info = sbinfo; #ifdef CONFIG_TMPFS /* * Per default we only allow half of the physical ram per * tmpfs instance, limiting inodes to one per page of lowmem; * but the internal instance is left unlimited. */ if (!(sb->s_flags & SB_KERNMOUNT)) { if (!(ctx->seen & SHMEM_SEEN_BLOCKS)) ctx->blocks = shmem_default_max_blocks(); if (!(ctx->seen & SHMEM_SEEN_INODES)) ctx->inodes = shmem_default_max_inodes(); if (!(ctx->seen & SHMEM_SEEN_INUMS)) ctx->full_inums = IS_ENABLED(CONFIG_TMPFS_INODE64); sbinfo->noswap = ctx->noswap; } else { sb->s_flags |= SB_NOUSER; } sb->s_export_op = &shmem_export_ops; sb->s_flags |= SB_NOSEC | SB_I_VERSION; #else sb->s_flags |= SB_NOUSER; #endif sbinfo->max_blocks = ctx->blocks; sbinfo->max_inodes = ctx->inodes; sbinfo->free_ispace = sbinfo->max_inodes * BOGO_INODE_SIZE; if (sb->s_flags & SB_KERNMOUNT) { sbinfo->ino_batch = alloc_percpu(ino_t); if (!sbinfo->ino_batch) goto failed; } sbinfo->uid = ctx->uid; sbinfo->gid = ctx->gid; sbinfo->full_inums = ctx->full_inums; sbinfo->mode = ctx->mode; sbinfo->huge = ctx->huge; sbinfo->mpol = ctx->mpol; ctx->mpol = NULL; raw_spin_lock_init(&sbinfo->stat_lock); if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) goto failed; spin_lock_init(&sbinfo->shrinklist_lock); INIT_LIST_HEAD(&sbinfo->shrinklist); sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_blocksize = PAGE_SIZE; sb->s_blocksize_bits = PAGE_SHIFT; sb->s_magic = TMPFS_MAGIC; sb->s_op = &shmem_ops; sb->s_time_gran = 1; #ifdef CONFIG_TMPFS_XATTR sb->s_xattr = shmem_xattr_handlers; #endif #ifdef CONFIG_TMPFS_POSIX_ACL sb->s_flags |= SB_POSIXACL; #endif uuid_t uuid; uuid_gen(&uuid); super_set_uuid(sb, uuid.b, sizeof(uuid)); #ifdef CONFIG_TMPFS_QUOTA if (ctx->seen & SHMEM_SEEN_QUOTA) { sb->dq_op = &shmem_quota_operations; sb->s_qcop = &dquot_quotactl_sysfile_ops; sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP; /* Copy the default limits from ctx into sbinfo */ memcpy(&sbinfo->qlimits, &ctx->qlimits, sizeof(struct shmem_quota_limits)); if (shmem_enable_quotas(sb, ctx->quota_types)) goto failed; } #endif /* CONFIG_TMPFS_QUOTA */ inode = shmem_get_inode(&nop_mnt_idmap, sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); if (IS_ERR(inode)) { error = PTR_ERR(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 error; } static int shmem_get_tree(struct fs_context *fc) { return get_tree_nodev(fc, shmem_fill_super); } static void shmem_free_fc(struct fs_context *fc) { struct shmem_options *ctx = fc->fs_private; if (ctx) { mpol_put(ctx->mpol); kfree(ctx); } } static const struct fs_context_operations shmem_fs_context_ops = { .free = shmem_free_fc, .get_tree = shmem_get_tree, #ifdef CONFIG_TMPFS .parse_monolithic = shmem_parse_options, .parse_param = shmem_parse_one, .reconfigure = shmem_reconfigure, #endif }; static struct kmem_cache *shmem_inode_cachep __ro_after_init; static struct inode *shmem_alloc_inode(struct super_block *sb) { struct shmem_inode_info *info; info = alloc_inode_sb(sb, shmem_inode_cachep, GFP_KERNEL); if (!info) return NULL; return &info->vfs_inode; } static void shmem_free_in_core_inode(struct inode *inode) { if (S_ISLNK(inode->i_mode)) kfree(inode->i_link); kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); } static void shmem_destroy_inode(struct inode *inode) { if (S_ISREG(inode->i_mode)) mpol_free_shared_policy(&SHMEM_I(inode)->policy); if (S_ISDIR(inode->i_mode)) simple_offset_destroy(shmem_get_offset_ctx(inode)); } static void shmem_init_inode(void *foo) { struct shmem_inode_info *info = foo; inode_init_once(&info->vfs_inode); } static void __init shmem_init_inodecache(void) { shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); } static void __init shmem_destroy_inodecache(void) { kmem_cache_destroy(shmem_inode_cachep); } /* Keep the page in page cache instead of truncating it */ static int shmem_error_remove_folio(struct address_space *mapping, struct folio *folio) { return 0; } static const struct address_space_operations shmem_aops = { .writepage = shmem_writepage, .dirty_folio = noop_dirty_folio, #ifdef CONFIG_TMPFS .write_begin = shmem_write_begin, .write_end = shmem_write_end, #endif #ifdef CONFIG_MIGRATION .migrate_folio = migrate_folio, #endif .error_remove_folio = shmem_error_remove_folio, }; static const struct file_operations shmem_file_operations = { .mmap = shmem_mmap, .open = shmem_file_open, .get_unmapped_area = shmem_get_unmapped_area, #ifdef CONFIG_TMPFS .llseek = shmem_file_llseek, .read_iter = shmem_file_read_iter, .write_iter = shmem_file_write_iter, .fsync = noop_fsync, .splice_read = shmem_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, .fileattr_get = shmem_fileattr_get, .fileattr_set = shmem_fileattr_set, #endif }; static const struct inode_operations shmem_dir_inode_operations = { #ifdef CONFIG_TMPFS .getattr = shmem_getattr, .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, .get_offset_ctx = shmem_get_offset_ctx, #endif #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, .fileattr_get = shmem_fileattr_get, .fileattr_set = shmem_fileattr_set, #endif #ifdef CONFIG_TMPFS_POSIX_ACL .setattr = shmem_setattr, .set_acl = simple_set_acl, #endif }; static const struct inode_operations shmem_special_inode_operations = { .getattr = shmem_getattr, #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, #endif #ifdef CONFIG_TMPFS_POSIX_ACL .setattr = shmem_setattr, .set_acl = simple_set_acl, #endif }; static const struct super_operations shmem_ops = { .alloc_inode = shmem_alloc_inode, .free_inode = shmem_free_in_core_inode, .destroy_inode = shmem_destroy_inode, #ifdef CONFIG_TMPFS .statfs = shmem_statfs, .show_options = shmem_show_options, #endif #ifdef CONFIG_TMPFS_QUOTA .get_dquots = shmem_get_dquots, #endif .evict_inode = shmem_evict_inode, .drop_inode = generic_delete_inode, .put_super = shmem_put_super, #ifdef CONFIG_TRANSPARENT_HUGEPAGE .nr_cached_objects = shmem_unused_huge_count, .free_cached_objects = shmem_unused_huge_scan, #endif }; static const struct vm_operations_struct shmem_vm_ops = { .fault = shmem_fault, .map_pages = filemap_map_pages, #ifdef CONFIG_NUMA .set_policy = shmem_set_policy, .get_policy = shmem_get_policy, #endif }; static const struct vm_operations_struct shmem_anon_vm_ops = { .fault = shmem_fault, .map_pages = filemap_map_pages, #ifdef CONFIG_NUMA .set_policy = shmem_set_policy, .get_policy = shmem_get_policy, #endif }; int shmem_init_fs_context(struct fs_context *fc) { struct shmem_options *ctx; ctx = kzalloc(sizeof(struct shmem_options), GFP_KERNEL); if (!ctx) return -ENOMEM; ctx->mode = 0777 | S_ISVTX; ctx->uid = current_fsuid(); ctx->gid = current_fsgid(); fc->fs_private = ctx; fc->ops = &shmem_fs_context_ops; return 0; } static struct file_system_type shmem_fs_type = { .owner = THIS_MODULE, .name = "tmpfs", .init_fs_context = shmem_init_fs_context, #ifdef CONFIG_TMPFS .parameters = shmem_fs_parameters, #endif .kill_sb = kill_litter_super, .fs_flags = FS_USERNS_MOUNT | FS_ALLOW_IDMAP, }; void __init shmem_init(void) { int error; shmem_init_inodecache(); #ifdef CONFIG_TMPFS_QUOTA error = register_quota_format(&shmem_quota_format); if (error < 0) { pr_err("Could not register quota format\n"); goto out3; } #endif error = register_filesystem(&shmem_fs_type); if (error) { pr_err("Could not register tmpfs\n"); goto out2; } shm_mnt = kern_mount(&shmem_fs_type); if (IS_ERR(shm_mnt)) { error = PTR_ERR(shm_mnt); pr_err("Could not kern_mount tmpfs\n"); goto out1; } #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY) SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; else shmem_huge = SHMEM_HUGE_NEVER; /* just in case it was patched */ /* * Default to setting PMD-sized THP to inherit the global setting and * disable all other multi-size THPs. */ huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER); #endif return; out1: unregister_filesystem(&shmem_fs_type); out2: #ifdef CONFIG_TMPFS_QUOTA unregister_quota_format(&shmem_quota_format); out3: #endif shmem_destroy_inodecache(); shm_mnt = ERR_PTR(error); } #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS) static ssize_t shmem_enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { static const int values[] = { SHMEM_HUGE_ALWAYS, SHMEM_HUGE_WITHIN_SIZE, SHMEM_HUGE_ADVISE, SHMEM_HUGE_NEVER, SHMEM_HUGE_DENY, SHMEM_HUGE_FORCE, }; int len = 0; int i; for (i = 0; i < ARRAY_SIZE(values); i++) { len += sysfs_emit_at(buf, len, shmem_huge == values[i] ? "%s[%s]" : "%s%s", i ? " " : "", shmem_format_huge(values[i])); } len += sysfs_emit_at(buf, len, "\n"); return len; } static ssize_t shmem_enabled_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { char tmp[16]; int huge; if (count + 1 > sizeof(tmp)) return -EINVAL; memcpy(tmp, buf, count); tmp[count] = '\0'; if (count && tmp[count - 1] == '\n') tmp[count - 1] = '\0'; huge = shmem_parse_huge(tmp); if (huge == -EINVAL) return -EINVAL; if (!has_transparent_hugepage() && huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) return -EINVAL; /* Do not override huge allocation policy with non-PMD sized mTHP */ if (huge == SHMEM_HUGE_FORCE && huge_shmem_orders_inherit != BIT(HPAGE_PMD_ORDER)) 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_RW(shmem_enabled); static DEFINE_SPINLOCK(huge_shmem_orders_lock); static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { int order = to_thpsize(kobj)->order; const char *output; if (test_bit(order, &huge_shmem_orders_always)) output = "[always] inherit within_size advise never"; else if (test_bit(order, &huge_shmem_orders_inherit)) output = "always [inherit] within_size advise never"; else if (test_bit(order, &huge_shmem_orders_within_size)) output = "always inherit [within_size] advise never"; else if (test_bit(order, &huge_shmem_orders_madvise)) output = "always inherit within_size [advise] never"; else output = "always inherit within_size advise [never]"; return sysfs_emit(buf, "%s\n", output); } static ssize_t thpsize_shmem_enabled_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { int order = to_thpsize(kobj)->order; ssize_t ret = count; if (sysfs_streq(buf, "always")) { spin_lock(&huge_shmem_orders_lock); clear_bit(order, &huge_shmem_orders_inherit); clear_bit(order, &huge_shmem_orders_madvise); clear_bit(order, &huge_shmem_orders_within_size); set_bit(order, &huge_shmem_orders_always); spin_unlock(&huge_shmem_orders_lock); } else if (sysfs_streq(buf, "inherit")) { /* Do not override huge allocation policy with non-PMD sized mTHP */ if (shmem_huge == SHMEM_HUGE_FORCE && order != HPAGE_PMD_ORDER) return -EINVAL; spin_lock(&huge_shmem_orders_lock); clear_bit(order, &huge_shmem_orders_always); clear_bit(order, &huge_shmem_orders_madvise); clear_bit(order, &huge_shmem_orders_within_size); set_bit(order, &huge_shmem_orders_inherit); spin_unlock(&huge_shmem_orders_lock); } else if (sysfs_streq(buf, "within_size")) { spin_lock(&huge_shmem_orders_lock); clear_bit(order, &huge_shmem_orders_always); clear_bit(order, &huge_shmem_orders_inherit); clear_bit(order, &huge_shmem_orders_madvise); set_bit(order, &huge_shmem_orders_within_size); spin_unlock(&huge_shmem_orders_lock); } else if (sysfs_streq(buf, "advise")) { spin_lock(&huge_shmem_orders_lock); clear_bit(order, &huge_shmem_orders_always); clear_bit(order, &huge_shmem_orders_inherit); clear_bit(order, &huge_shmem_orders_within_size); set_bit(order, &huge_shmem_orders_madvise); spin_unlock(&huge_shmem_orders_lock); } else if (sysfs_streq(buf, "never")) { spin_lock(&huge_shmem_orders_lock); clear_bit(order, &huge_shmem_orders_always); clear_bit(order, &huge_shmem_orders_inherit); clear_bit(order, &huge_shmem_orders_within_size); clear_bit(order, &huge_shmem_orders_madvise); spin_unlock(&huge_shmem_orders_lock); } else { ret = -EINVAL; } return ret; } struct kobj_attribute thpsize_shmem_enabled_attr = __ATTR(shmem_enabled, 0644, thpsize_shmem_enabled_show, thpsize_shmem_enabled_store); #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */ #else /* !CONFIG_SHMEM */ /* * tiny-shmem: simple shmemfs and tmpfs using ramfs code * * This is intended for small system where the benefits of the full * shmem code (swap-backed and resource-limited) are outweighed by * their complexity. On systems without swap this code should be * effectively equivalent, but much lighter weight. */ static struct file_system_type shmem_fs_type = { .name = "tmpfs", .init_fs_context = ramfs_init_fs_context, .parameters = ramfs_fs_parameters, .kill_sb = ramfs_kill_sb, .fs_flags = FS_USERNS_MOUNT, }; void __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)); } int shmem_unuse(unsigned int type) { return 0; } int shmem_lock(struct file *file, int lock, struct ucounts *ucounts) { 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 mm_get_unmapped_area(current->mm, 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_anon_vm_ops generic_file_vm_ops #define shmem_file_operations ramfs_file_operations #define shmem_acct_size(flags, size) 0 #define shmem_unacct_size(flags, size) do {} while (0) static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block *sb, struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { struct inode *inode = ramfs_get_inode(sb, dir, mode, dev); return inode ? inode : ERR_PTR(-ENOSPC); } #endif /* CONFIG_SHMEM */ /* common code */ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name, loff_t size, unsigned long flags, unsigned int i_flags) { struct inode *inode; struct file *res; if (IS_ERR(mnt)) return ERR_CAST(mnt); if (size < 0 || size > MAX_LFS_FILESIZE) return ERR_PTR(-EINVAL); if (shmem_acct_size(flags, size)) return ERR_PTR(-ENOMEM); if (is_idmapped_mnt(mnt)) return ERR_PTR(-EINVAL); inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); if (IS_ERR(inode)) { shmem_unacct_size(flags, size); return ERR_CAST(inode); } inode->i_flags |= i_flags; inode->i_size = size; clear_nlink(inode); /* It is unlinked */ res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); if (!IS_ERR(res)) res = alloc_file_pseudo(inode, mnt, name, O_RDWR, &shmem_file_operations); if (IS_ERR(res)) iput(inode); return res; } /** * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be * kernel internal. There will be NO LSM permission checks against the * underlying inode. So users of this interface must do LSM checks at a * higher layer. The users are the big_key and shm implementations. LSM * checks are provided at the key or shm level rather than the inode. * @name: name for dentry (to be seen in /proc/<pid>/maps * @size: size to be set for the file * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size */ struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) { return __shmem_file_setup(shm_mnt, name, size, flags, S_PRIVATE); } EXPORT_SYMBOL_GPL(shmem_kernel_file_setup); /** * shmem_file_setup - get an unlinked file living in tmpfs * @name: name for dentry (to be seen in /proc/<pid>/maps * @size: size to be set for the file * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size */ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) { return __shmem_file_setup(shm_mnt, name, size, flags, 0); } EXPORT_SYMBOL_GPL(shmem_file_setup); /** * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs * @mnt: the tmpfs mount where the file will be created * @name: name for dentry (to be seen in /proc/<pid>/maps * @size: size to be set for the file * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size */ struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, const char *name, loff_t size, unsigned long flags) { return __shmem_file_setup(mnt, name, size, flags, 0); } EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt); /** * shmem_zero_setup - setup a shared anonymous mapping * @vma: the vma to be mmapped is prepared by do_mmap */ int shmem_zero_setup(struct vm_area_struct *vma) { struct file *file; loff_t size = vma->vm_end - vma->vm_start; /* * Cloning a new file under mmap_lock leads to a lock ordering conflict * between XFS directory reading and selinux: since this file is only * accessible to the user through its mapping, use S_PRIVATE flag to * bypass file security, in the same way as shmem_kernel_file_setup(). */ file = shmem_kernel_file_setup("dev/zero", size, vma->vm_flags); if (IS_ERR(file)) return PTR_ERR(file); if (vma->vm_file) fput(vma->vm_file); vma->vm_file = file; vma->vm_ops = &shmem_anon_vm_ops; return 0; } /** * shmem_read_folio_gfp - read into page cache, using specified page allocation flags. * @mapping: the folio's address_space * @index: the folio 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 ->read_folio() 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 folio *shmem_read_folio_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp) { #ifdef CONFIG_SHMEM struct inode *inode = mapping->host; struct folio *folio; int error; error = shmem_get_folio_gfp(inode, index, &folio, SGP_CACHE, gfp, NULL, NULL); if (error) return ERR_PTR(error); folio_unlock(folio); return folio; #else /* * The tiny !SHMEM case uses ramfs without swap */ return mapping_read_folio_gfp(mapping, index, gfp); #endif } EXPORT_SYMBOL_GPL(shmem_read_folio_gfp); struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp) { struct folio *folio = shmem_read_folio_gfp(mapping, index, gfp); struct page *page; if (IS_ERR(folio)) return &folio->page; page = folio_file_page(folio, index); if (PageHWPoison(page)) { folio_put(folio); return ERR_PTR(-EIO); } return page; } EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp);
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