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Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 5998 |
1 files changed, 5998 insertions, 0 deletions
diff --git a/mm/shmem.c b/mm/shmem.c new file mode 100644 index 000000000..897fa2b61 --- /dev/null +++ b/mm/shmem.c @@ -0,0 +1,5998 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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> + */ + +#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/filelock.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 <linux/unicode.h> +#include <linux/swap_ops.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/folio_batch.h> +#include <linux/percpu_counter.h> +#include <linux/falloc.h> +#include <linux/splice.h> +#include <linux/security.h> +#include <linux/leafops.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 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_writeout 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 writeout 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; +#if IS_ENABLED(CONFIG_UNICODE) + struct unicode_map *encoding; + bool strict_encoding; +#endif +#define SHMEM_SEEN_BLOCKS 1 +#define SHMEM_SEEN_INODES 2 +#define SHMEM_SEEN_HUGE 4 +#define SHMEM_SEEN_INUMS 8 +#define SHMEM_SEEN_QUOTA 16 +}; + +#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; +static bool shmem_orders_configured __initdata; +#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 vm_fault *vmf, 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 & SHMEM_F_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 & SHMEM_F_NORESERVE)) + vm_unacct_memory(VM_ACCT(size)); +} + +static inline int shmem_reacct_size(unsigned long flags, + loff_t oldsize, loff_t newsize) +{ + if (!(flags & SHMEM_F_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 & SHMEM_F_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 & SHMEM_F_NORESERVE) + vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); +} + +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(const struct address_space *mapping) +{ + return mapping->a_ops == &shmem_aops; +} +EXPORT_SYMBOL_GPL(shmem_mapping); + +bool vma_is_anon_shmem(const struct vm_area_struct *vma) +{ + return vma->vm_ops == &shmem_anon_vm_ops; +} + +bool vma_is_shmem(const struct vm_area_struct *vma) +{ + return vma_is_anon_shmem(vma) || vma->vm_ops == &shmem_vm_ops; +} + +static LIST_HEAD(shmem_swaplist); +static DEFINE_SPINLOCK(shmem_swaplist_lock); + +#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) + * + * Return: true if swapped was incremented from 0, for shmem_writeout(). + */ +bool shmem_recalc_inode(struct inode *inode, long alloced, long swapped) +{ + struct shmem_inode_info *info = SHMEM_I(inode); + bool first_swapped = false; + 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_writeout() 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) { + if (info->swapped == swapped) + first_swapped = true; + 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); + return first_swapped; +} + +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 or split by a racing thread. + * + * Checking folio is not enough: by the time a swapcache folio is locked, it + * might be reused, and again be swapcache, using the same swap as before. + * Returns the swap entry's order if it still presents, else returns -1. + */ +static int shmem_confirm_swap(struct address_space *mapping, pgoff_t index, + swp_entry_t swap) +{ + XA_STATE(xas, &mapping->i_pages, index); + int ret = -1; + void *entry; + + rcu_read_lock(); + do { + entry = xas_load(&xas); + if (entry == swp_to_radix_entry(swap)) + ret = xas_get_order(&xas); + } while (xas_retry(&xas, entry)); + rcu_read_unlock(); + return ret; +} + +/* + * 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 madvise() hints; + * SHMEM_HUGE_ADVISE: + * only allocate huge pages if requested with 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 */ + +#if defined(CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_NEVER) +#define SHMEM_HUGE_DEFAULT SHMEM_HUGE_NEVER +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ALWAYS) +#define SHMEM_HUGE_DEFAULT SHMEM_HUGE_ALWAYS +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_WITHIN_SIZE) +#define SHMEM_HUGE_DEFAULT SHMEM_HUGE_WITHIN_SIZE +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_SHMEM_HUGE_ADVISE) +#define SHMEM_HUGE_DEFAULT SHMEM_HUGE_ADVISE +#else +#define SHMEM_HUGE_DEFAULT SHMEM_HUGE_NEVER +#endif + +static int shmem_huge __read_mostly = SHMEM_HUGE_DEFAULT; + +#undef SHMEM_HUGE_DEFAULT + +#if defined(CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_NEVER) +#define TMPFS_HUGE_DEFAULT SHMEM_HUGE_NEVER +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ALWAYS) +#define TMPFS_HUGE_DEFAULT SHMEM_HUGE_ALWAYS +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_WITHIN_SIZE) +#define TMPFS_HUGE_DEFAULT SHMEM_HUGE_WITHIN_SIZE +#elif defined(CONFIG_TRANSPARENT_HUGEPAGE_TMPFS_HUGE_ADVISE) +#define TMPFS_HUGE_DEFAULT SHMEM_HUGE_ADVISE +#else +#define TMPFS_HUGE_DEFAULT SHMEM_HUGE_NEVER +#endif + +static int tmpfs_huge __read_mostly = TMPFS_HUGE_DEFAULT; + +#undef TMPFS_HUGE_DEFAULT + +static unsigned int shmem_get_orders_within_size(struct inode *inode, + unsigned long within_size_orders, pgoff_t index, + loff_t write_end) +{ + pgoff_t aligned_index; + unsigned long order; + loff_t i_size; + + order = highest_order(within_size_orders); + while (within_size_orders) { + aligned_index = round_up(index + 1, 1 << order); + i_size = max(write_end, i_size_read(inode)); + i_size = round_up(i_size, PAGE_SIZE); + if (i_size >> PAGE_SHIFT >= aligned_index) + return within_size_orders; + + order = next_order(&within_size_orders, order); + } + + return 0; +} + +static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index, + loff_t write_end, bool shmem_huge_force, + struct vm_area_struct *vma, + vm_flags_t vm_flags) +{ + unsigned int maybe_pmd_order = HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER ? + 0 : BIT(HPAGE_PMD_ORDER); + unsigned long within_size_orders; + + if (!S_ISREG(inode->i_mode)) + return 0; + if (shmem_huge == SHMEM_HUGE_DENY) + return 0; + if (shmem_huge_force || shmem_huge == SHMEM_HUGE_FORCE) + return maybe_pmd_order; + + /* + * The huge order allocation for anon shmem is controlled through + * the mTHP interface, so we still use PMD-sized huge order to + * check whether global control is enabled. + * + * For tmpfs with 'huge=always' or 'huge=within_size' mount option, + * we will always try PMD-sized order first. If that failed, it will + * fall back to small large folios. + */ + switch (SHMEM_SB(inode->i_sb)->huge) { + case SHMEM_HUGE_ALWAYS: + return THP_ORDERS_ALL_FILE_DEFAULT; + case SHMEM_HUGE_WITHIN_SIZE: + within_size_orders = shmem_get_orders_within_size(inode, + THP_ORDERS_ALL_FILE_DEFAULT, index, write_end); + if (within_size_orders > 0) + return within_size_orders; + + fallthrough; + case SHMEM_HUGE_ADVISE: + if (vm_flags & VM_HUGEPAGE) + return THP_ORDERS_ALL_FILE_DEFAULT; + fallthrough; + default: + return 0; + } +} + +static int shmem_parse_huge(const char *str) +{ + int huge; + + if (!str) + return -EINVAL; + + if (!strcmp(str, "never")) + huge = SHMEM_HUGE_NEVER; + else if (!strcmp(str, "always")) + huge = SHMEM_HUGE_ALWAYS; + else if (!strcmp(str, "within_size")) + huge = SHMEM_HUGE_WITHIN_SIZE; + else if (!strcmp(str, "advise")) + huge = SHMEM_HUGE_ADVISE; + else if (!strcmp(str, "deny")) + huge = SHMEM_HUGE_DENY; + else if (!strcmp(str, "force")) + huge = SHMEM_HUGE_FORCE; + else + 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; + + return huge; +} + +#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_free) +{ + LIST_HEAD(list), *pos, *next; + struct inode *inode; + struct shmem_inode_info *info; + struct folio *folio; + unsigned long batch = sc ? sc->nr_to_scan : 128; + unsigned long split = 0, freed = 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; + } + + list_move(&info->shrinklist, &list); +next: + sbinfo->shrinklist_len--; + if (!--batch) + break; + } + spin_unlock(&sbinfo->shrinklist_lock); + + list_for_each_safe(pos, next, &list) { + pgoff_t next, end; + loff_t i_size; + int ret; + + info = list_entry(pos, struct shmem_inode_info, shrinklist); + inode = &info->vfs_inode; + + if (nr_to_free && freed >= nr_to_free) + goto move_back; + + i_size = i_size_read(inode); + folio = filemap_get_entry(inode->i_mapping, i_size / PAGE_SIZE); + if (!folio || xa_is_value(folio)) + goto drop; + + /* No large folio at the end of the file: nothing to split */ + if (!folio_test_large(folio)) { + folio_put(folio); + goto drop; + } + + /* Check if there is anything to gain from splitting */ + next = folio_next_index(folio); + end = shmem_fallocend(inode, DIV_ROUND_UP(i_size, PAGE_SIZE)); + if (end <= folio->index || end >= next) { + 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; + + freed += next - end; + 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); + + /* + * The per-superblock shrinklist is filesystem-global and does not + * honour sc->memcg, so it is only meaningful on the global (kswapd or + * root direct reclaim) shrink path. Skip the per-memcg iterations of + * shrink_slab_memcg() to avoid queueing duplicate global work. + */ + if (!mem_cgroup_shrink_is_root(sc)) + return 0; + + 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_free) +{ + return 0; +} + +static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index, + loff_t write_end, bool shmem_huge_force, + struct vm_area_struct *vma, + vm_flags_t vm_flags) +{ + return 0; +} +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +static void shmem_update_stats(struct folio *folio, int nr_pages) +{ + if (folio_test_pmd_mappable(folio)) + lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, nr_pages); + lruvec_stat_mod_folio(folio, NR_FILE_PAGES, nr_pages); + lruvec_stat_mod_folio(folio, NR_SHMEM, nr_pages); +} + +/* + * Somewhat like filemap_add_folio, but error if expected item has gone. + */ +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)); + unsigned long nr = folio_nr_pages(folio); + swp_entry_t iter, swap; + void *entry; + + 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); + + folio_ref_add(folio, nr); + folio->mapping = mapping; + folio->index = index; + + gfp &= GFP_RECLAIM_MASK; + folio_throttle_swaprate(folio, gfp); + swap = radix_to_swp_entry(expected); + + do { + iter = swap; + xas_lock_irq(&xas); + xas_for_each_conflict(&xas, entry) { + /* + * The range must either be empty, or filled with + * expected swap entries. Shmem swap entries are never + * partially freed without split of both entry and + * folio, so there shouldn't be any holes. + */ + if (!expected || entry != swp_to_radix_entry(iter)) { + xas_set_err(&xas, -EEXIST); + goto unlock; + } + iter.val += 1 << xas_get_order(&xas); + } + if (expected && iter.val - nr != swap.val) { + xas_set_err(&xas, -EEXIST); + goto unlock; + } + xas_store(&xas, folio); + if (xas_error(&xas)) + goto unlock; + shmem_update_stats(folio, 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; + shmem_update_stats(folio, -nr); + xa_unlock_irq(&mapping->i_pages); + folio_put_refs(folio, nr); + BUG_ON(error); +} + +/* + * Remove swap entry from page cache, free the swap and its page cache. Returns + * the number of pages being freed. 0 means entry not found in XArray (0 pages + * being freed). + */ +static long shmem_free_swap(struct address_space *mapping, + pgoff_t index, pgoff_t end, void *radswap) +{ + XA_STATE(xas, &mapping->i_pages, index); + unsigned int nr_pages = 0; + pgoff_t base; + void *entry; + + xas_lock_irq(&xas); + entry = xas_load(&xas); + if (entry == radswap) { + nr_pages = 1 << xas_get_order(&xas); + base = round_down(xas.xa_index, nr_pages); + if (base < index || base + nr_pages - 1 > end) + nr_pages = 0; + else + xas_store(&xas, NULL); + } + xas_unlock_irq(&xas); + + if (nr_pages) + swap_put_entries_direct(radix_to_swp_entry(radswap), nr_pages); + + return nr_pages; +} + +/* + * 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 folio *folio; + unsigned long swapped = 0; + unsigned long max = end - 1; + + rcu_read_lock(); + xas_for_each(&xas, folio, max) { + if (xas_retry(&xas, folio)) + continue; + if (xa_is_value(folio)) + swapped += 1 << xas_get_order(&xas); + 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; + const pgoff_t pgoff = vma_start_pgoff(vma); + const pgoff_t pgoff_end = vma_end_pgoff(vma); + 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 (!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, pgoff, pgoff_end); +} + +/* + * 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, 0, &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, uoff_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[FOLIO_BATCH_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], + end - 1, 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_next_pos(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)) { + int order; + long swaps_freed; + + if (unfalloc) + continue; + swaps_freed = shmem_free_swap(mapping, indices[i], + end - 1, folio); + if (!swaps_freed) { + pgoff_t base = indices[i]; + + order = shmem_confirm_swap(mapping, indices[i], + radix_to_swp_entry(folio)); + /* + * If found a large swap entry cross the end or start + * border, skip it as the truncate_inode_partial_folio + * above should have at least zerod its content once. + */ + if (order > 0) { + base = round_down(base, 1 << order); + if (base < start || base + (1 << order) > end) + continue; + } + /* Swap was replaced by page or extended, retry */ + index = base; + break; + } + nr_swaps_freed += 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, uoff_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); + + /* Fast-path hint; recalc under info->lock corrects any stale read. */ + if (data_race(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_huge_global_enabled(inode, 0, 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) { + if (info->flags & SHMEM_F_MAPPING_FROZEN) + return -EPERM; + 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)); + spin_lock(&shmem_swaplist_lock); + /* ...but beware of the race if we peeked too early */ + if (!atomic_read(&info->stop_eviction)) + list_del_init(&info->swaplist); + spin_unlock(&shmem_swaplist_lock); + } + } + + simple_xattrs_free(&sbinfo->xa_cache, &info->xattrs, sbinfo->max_inodes ? &freed : NULL); + + shmem_free_inode(inode->i_sb, freed); + if (inode->i_blocks) + pr_warn("%s: ino=%llu i_blocks=%llu alloced=%lu swapped=%lu nrpages=%lu\n", + __func__, inode->i_ino, inode->i_blocks, + info->alloced, info->swapped, inode->i_mapping->nrpages); + clear_inode(inode); +#ifdef CONFIG_TMPFS_QUOTA + dquot_free_inode(inode); + dquot_drop(inode); +#endif +} + +static unsigned 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 folio_batch_count(fbatch); +} + +/* + * 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]; + + 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[FOLIO_BATCH_SIZE]; + int ret = 0; + + do { + folio_batch_init(&fbatch); + if (!shmem_find_swap_entries(mapping, start, &fbatch, + indices, type)) { + 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; + + spin_lock(&shmem_swaplist_lock); +start_over: + 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); + spin_unlock(&shmem_swaplist_lock); + + error = shmem_unuse_inode(&info->vfs_inode, type); + cond_resched(); + + spin_lock(&shmem_swaplist_lock); + if (atomic_dec_and_test(&info->stop_eviction)) + wake_up_var(&info->stop_eviction); + if (error) + break; + if (list_empty(&info->swaplist)) + goto start_over; + next = list_next_entry(info, swaplist); + if (!info->swapped) + list_del_init(&info->swaplist); + } + spin_unlock(&shmem_swaplist_lock); + + return error; +} + +/** + * shmem_writeout - Write the folio to swap + * @ctx: swap I/O context + * @folio: The folio to write + * @folio_list: list to put back folios on split + * + * Move the folio from the page cache to the swap cache. + */ +int shmem_writeout(struct swap_io_ctx *ctx, struct folio *folio, + struct list_head *folio_list) +{ + 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); + pgoff_t index; + int nr_pages; + bool split = false; + + if ((info->flags & SHMEM_F_LOCKED) || sbinfo->noswap) + goto redirty; + + if (!total_swap_pages) + goto redirty; + + /* + * If CONFIG_THP_SWAP is not enabled, the large folio should be + * split when swapping. + * + * And shrinkage of pages beyond i_size does not split swap, so + * swapout of a large folio crossing i_size needs to split too + * (unless fallocate has been used to preallocate beyond EOF). + */ + if (folio_test_large(folio)) { + index = shmem_fallocend(inode, + DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE)); + if ((index > folio->index && index < folio_next_index(folio)) || + !IS_ENABLED(CONFIG_THP_SWAP)) + split = true; + } + + if (split) { + int order; + +try_split: + order = folio_order(folio); + /* Ensure the subpages are still dirty */ + folio_test_set_dirty(folio); + if (split_folio_to_list(folio, folio_list)) + goto redirty; + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (order >= HPAGE_PMD_ORDER) { + count_memcg_folio_events(folio, THP_SWPOUT_FALLBACK, 1); + count_vm_event(THP_SWPOUT_FALLBACK); + } +#endif + count_mthp_stat(order, MTHP_STAT_SWPOUT_FALLBACK); + + folio_clear_dirty(folio); + } + + index = folio->index; + nr_pages = folio_nr_pages(folio); + + /* + * 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 (READ_ONCE(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 += nr_pages; + 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); + } + + if (!folio_alloc_swap(folio)) { + bool first_swapped = shmem_recalc_inode(inode, 0, nr_pages); + int error; + + /* + * Add inode to shmem_unuse()'s list of swapped-out inodes, + * if it's not already there. Do it now before the folio is + * removed from page cache, when its pagelock no longer + * protects the inode from eviction. And do it now, after + * we've incremented swapped, because shmem_unuse() will + * prune a !swapped inode from the swaplist. + */ + if (first_swapped) { + spin_lock(&shmem_swaplist_lock); + if (list_empty(&info->swaplist)) + list_add(&info->swaplist, &shmem_swaplist); + spin_unlock(&shmem_swaplist_lock); + } + + folio_dup_swap(folio, NULL); + shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap)); + + BUG_ON(folio_mapped(folio)); + error = swap_writeout(ctx, folio); + if (error != AOP_WRITEPAGE_ACTIVATE) { + /* folio has been unlocked */ + return error; + } + + /* + * The intention here is to avoid holding on to the swap when + * zswap was unable to compress and unable to writeback; but + * it will be appropriate if other reactivate cases are added. + */ + error = shmem_add_to_page_cache(folio, mapping, index, + swp_to_radix_entry(folio->swap), + __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN); + /* Swap entry might be erased by racing shmem_free_swap() */ + if (!error) { + shmem_recalc_inode(inode, 0, -nr_pages); + folio_put_swap(folio, NULL); + } + + /* + * The swap_cache_del_folio() below could be left for + * shrink_folio_list()'s folio_free_swap() to dispose of; + * but I'm a little nervous about letting this folio out of + * shmem_writeout() in a hybrid half-tmpfs-half-swap state + * e.g. folio_mapping(folio) might give an unexpected answer. + */ + swap_cache_del_folio(folio); + goto redirty; + } + if (nr_pages > 1) + goto try_split; +redirty: + folio_mark_dirty(folio); + return AOP_WRITEPAGE_ACTIVATE; /* Return with folio locked */ +} + +int shmem_write_folio(struct folio *folio) +{ + struct swap_io_ctx ctx = {}; + int err; + + err = shmem_writeout(&ctx, folio, NULL); + swap_write_submit(&ctx); + return err; +} +EXPORT_SYMBOL_GPL(shmem_write_folio); + +#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; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +bool shmem_hpage_pmd_enabled(void) +{ + if (shmem_huge == SHMEM_HUGE_DENY) + return false; + if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_always)) + return true; + if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_madvise)) + return true; + if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_within_size)) + return true; + if (test_bit(HPAGE_PMD_ORDER, &huge_shmem_orders_inherit) && + shmem_huge != SHMEM_HUGE_NEVER) + return true; + + return false; +} + +unsigned long shmem_allowable_huge_orders(struct inode *inode, + struct vm_area_struct *vma, pgoff_t index, + loff_t write_end, bool shmem_huge_force) +{ + unsigned long mask = READ_ONCE(huge_shmem_orders_always); + unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size); + vm_flags_t vm_flags = vma ? vma->vm_flags : 0; + unsigned int global_orders; + + if (thp_disabled_by_hw() || (vma && vma_thp_disabled(vma, vm_flags, shmem_huge_force))) + return 0; + + global_orders = shmem_huge_global_enabled(inode, index, write_end, + shmem_huge_force, vma, vm_flags); + /* Tmpfs huge pages allocation */ + if (!vma || !vma_is_anon_shmem(vma)) + return global_orders; + + /* + * 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. */ + mask |= shmem_get_orders_within_size(inode, within_size_orders, index, 0); + + if (vm_flags & VM_HUGEPAGE) + mask |= READ_ONCE(huge_shmem_orders_madvise); + + if (global_orders > 0) + 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 ? vmf->vma : NULL; + pgoff_t aligned_index; + unsigned long pages; + int order; + + if (vma) { + 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); + /* + * 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, &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); + unsigned long suitable_orders = 0; + struct folio *folio = NULL; + pgoff_t aligned_index; + long pages; + int error, order; + + if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) + orders = 0; + + if (orders > 0) { + suitable_orders = shmem_suitable_orders(inode, vmf, + mapping, index, orders); + + order = highest_order(suitable_orders); + while (suitable_orders) { + pages = 1UL << order; + aligned_index = round_down(index, pages); + folio = shmem_alloc_folio(gfp, order, info, aligned_index); + if (folio) { + index = aligned_index; + goto allocated; + } + + if (pages == HPAGE_PMD_NR) + count_vm_event(THP_FILE_FALLBACK); + count_mthp_stat(order, MTHP_STAT_SHMEM_FALLBACK); + 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); + } + count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK); + count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_FALLBACK_CHARGE); + } + 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, pages); + /* + * 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); +} + +static struct folio *shmem_swap_alloc_folio(struct inode *inode, + struct vm_fault *vmf, pgoff_t index, + swp_entry_t entry, int order, gfp_t gfp) +{ + pgoff_t ilx; + struct folio *folio; + struct mempolicy *mpol; + struct shmem_inode_info *info = SHMEM_I(inode); + + if ((vmf && unlikely(userfaultfd_armed(vmf->vma))) || + !zswap_never_enabled()) + order = 0; + +again: + mpol = shmem_get_pgoff_policy(info, index, order, &ilx); + folio = swapin_sync(entry, gfp, BIT(order), vmf, mpol, ilx); + mpol_cond_put(mpol); + + if (!IS_ERR(folio)) + return folio; + + if (order) { + order = 0; + goto again; + } + + return folio; +} + +/* + * 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 vm_area_struct *vma) +{ + struct swap_cluster_info *ci; + struct folio *new, *old = *foliop; + swp_entry_t entry = old->swap; + int nr_pages = folio_nr_pages(old); + int error = 0; + + /* + * 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; +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (nr_pages > 1) { + gfp_t huge_gfp = vma_thp_gfp_mask(vma); + + gfp = thp_shmem_limit_gfp_mask(huge_gfp, gfp); + } +#endif + + new = shmem_alloc_folio(gfp, folio_order(old), info, index); + if (!new) + return -ENOMEM; + + folio_ref_add(new, nr_pages); + 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); + + ci = swap_cluster_get_and_lock_irq(old); + __swap_cache_replace_folio(ci, old, new); + mem_cgroup_replace_folio(old, new); + shmem_update_stats(new, nr_pages); + shmem_update_stats(old, -nr_pages); + swap_cluster_unlock_irq(ci); + + folio_add_lru(new); + *foliop = new; + + folio_clear_swapcache(old); + old->private = NULL; + + folio_unlock(old); + /* + * The old folio are removed from swap cache, drop the 'nr_pages' + * reference, as well as one temporary reference getting from swap + * cache. + */ + folio_put_refs(old, nr_pages + 1); + 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; + int nr_pages; + + 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; + + nr_pages = folio_nr_pages(folio); + folio_wait_writeback(folio); + folio_put_swap(folio, NULL); + swap_cache_del_folio(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, -nr_pages, -nr_pages); +} + +static int shmem_split_large_entry(struct inode *inode, pgoff_t index, + swp_entry_t swap, gfp_t gfp) +{ + struct address_space *mapping = inode->i_mapping; + XA_STATE_ORDER(xas, &mapping->i_pages, index, 0); + int split_order = 0; + int i; + + /* Convert user data gfp flags to xarray node gfp flags */ + gfp &= GFP_RECLAIM_MASK; + + for (;;) { + void *old = NULL; + int cur_order; + pgoff_t swap_index; + + xas_lock_irq(&xas); + old = xas_load(&xas); + if (!xa_is_value(old) || swp_to_radix_entry(swap) != old) { + xas_set_err(&xas, -EEXIST); + goto unlock; + } + + cur_order = xas_get_order(&xas); + if (!cur_order) + goto unlock; + + /* Try to split large swap entry in pagecache */ + swap_index = round_down(index, 1 << cur_order); + split_order = xas_try_split_min_order(cur_order); + + while (cur_order > 0) { + pgoff_t aligned_index = + round_down(index, 1 << cur_order); + pgoff_t swap_offset = aligned_index - swap_index; + + xas_set_order(&xas, index, split_order); + xas_try_split(&xas, old, cur_order); + if (xas_error(&xas)) + goto unlock; + + /* + * Re-set the swap entry after splitting, and the swap + * offset of the original large entry must be continuous. + */ + for (i = 0; i < 1 << cur_order; + i += (1 << split_order)) { + swp_entry_t tmp; + + tmp = swp_entry(swp_type(swap), + swp_offset(swap) + swap_offset + + i); + __xa_store(&mapping->i_pages, aligned_index + i, + swp_to_radix_entry(tmp), 0); + } + cur_order = split_order; + split_order = xas_try_split_min_order(split_order); + } + +unlock: + xas_unlock_irq(&xas); + + if (!xas_nomem(&xas, gfp)) + break; + } + + if (xas_error(&xas)) + return xas_error(&xas); + + return 0; +} + +/* + * 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 vm_fault *vmf, + vm_fault_t *fault_type) +{ + struct address_space *mapping = inode->i_mapping; + struct vm_area_struct *vma = vmf ? vmf->vma : NULL; + struct mm_struct *fault_mm = vmf ? vmf->vma->vm_mm : NULL; + struct shmem_inode_info *info = SHMEM_I(inode); + swp_entry_t swap; + softleaf_t index_entry; + struct swap_info_struct *si; + struct folio *folio = NULL; + int error, nr_pages, order; + pgoff_t offset; + + VM_BUG_ON(!*foliop || !xa_is_value(*foliop)); + index_entry = radix_to_swp_entry(*foliop); + swap = index_entry; + *foliop = NULL; + + if (softleaf_is_poison_marker(index_entry)) + return -EIO; + + si = get_swap_device(index_entry); + order = shmem_confirm_swap(mapping, index, index_entry); + if (unlikely(!si)) { + if (order < 0) + return -EEXIST; + else + return -EINVAL; + } + if (unlikely(order < 0)) { + put_swap_device(si); + return -EEXIST; + } + + /* index may point to the middle of a large entry, get the sub entry */ + if (order) { + offset = index - round_down(index, 1 << order); + swap = swp_entry(swp_type(swap), swp_offset(swap) + offset); + } + + /* Look it up and read it in.. */ + folio = swap_cache_get_folio(swap); + if (!folio) { + if (data_race(si->flags & SWP_SYNCHRONOUS_IO)) { + /* Direct swapin skipping swap cache & readahead */ + folio = shmem_swap_alloc_folio(inode, vmf, index, + swap, order, gfp); + } else { + /* Cached swapin only supports order 0 folio */ + folio = shmem_swapin_cluster(swap, gfp, info, index); + } + if (IS_ERR_OR_NULL(folio)) { + if (IS_ERR(folio)) + error = PTR_ERR(folio); + else + error = -ENOMEM; + folio = NULL; + goto failed; + } + if (fault_type) { + *fault_type |= VM_FAULT_MAJOR; + count_vm_event(PGMAJFAULT); + count_memcg_event_mm(fault_mm, PGMAJFAULT); + } + } else { + swap_update_readahead(folio, NULL, 0); + } + + if (order > folio_order(folio)) { + /* + * Swapin may get smaller folios due to various reasons: + * It may fallback to order 0 due to memory pressure or race, + * swap readahead may swap in order 0 folios into swapcache + * asynchronously, while the shmem mapping can still stores + * large swap entries. In such cases, we should split the + * large swap entry to prevent possible data corruption. + */ + error = shmem_split_large_entry(inode, index, index_entry, gfp); + if (error) + goto failed_nolock; + } + + /* + * If the folio is large, round down swap and index by folio size. + * No matter what race occurs, the swap layer ensures we either get + * a valid folio that has its swap entry aligned by size, or a + * temporarily invalid one which we'll abort very soon and retry. + * + * shmem_add_to_page_cache ensures the whole range contains expected + * entries and prevents any corruption, so any race split is fine + * too, it will succeed as long as the entries are still there. + */ + nr_pages = folio_nr_pages(folio); + if (nr_pages > 1) { + swap.val = round_down(swap.val, nr_pages); + index = round_down(index, nr_pages); + } + + /* + * We have to do this with the folio locked to prevent races. + * The shmem_confirm_swap below only checks if the first swap + * entry matches the folio, that's enough to ensure the folio + * is not used outside of shmem, as shmem swap entries + * and swap cache folios are never partially freed. + */ + folio_lock(folio); + if (!folio_matches_swap_entry(folio, swap) || + shmem_confirm_swap(mapping, index, swap) < 0) { + 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, vma); + 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, -nr_pages); + + if (sgp == SGP_WRITE) + folio_mark_accessed(folio); + + folio_put_swap(folio, NULL); + swap_cache_del_folio(folio); + folio_mark_dirty(folio); + put_swap_device(si); + + *foliop = folio; + return 0; +failed: + if (shmem_confirm_swap(mapping, index, swap) < 0) + error = -EEXIST; + if (error == -EIO) + shmem_set_folio_swapin_error(inode, index, folio, swap); +unlock: + if (folio) + folio_unlock(folio); +failed_nolock: + if (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, + loff_t write_end, 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; + 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, vmf, 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; + } + + /* Find hugepage orders that are allowed for anonymous shmem and tmpfs. */ + orders = shmem_allowable_huge_orders(inode, vma, index, write_end, false); + if (orders > 0) { + gfp_t huge_gfp; + + huge_gfp = vma_thp_gfp_mask(vma); + huge_gfp = thp_shmem_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); + count_mthp_stat(folio_order(folio), MTHP_STAT_SHMEM_ALLOC); + 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)) { + 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. + * @write_end: end of a write, could extend inode size + * @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, loff_t write_end, + struct folio **foliop, enum sgp_type sgp) +{ + return shmem_get_folio_gfp(inode, index, write_end, 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(READ_ONCE(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, 0, &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(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(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 = linear_page_index(vma, addr); + 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 & SHMEM_F_LOCKED)) { + if (!user_shm_lock(inode->i_size, ucounts)) + goto out_nomem; + info->flags |= SHMEM_F_LOCKED; + mapping_set_unevictable(file->f_mapping); + } + if (!lock && (info->flags & SHMEM_F_LOCKED) && ucounts) { + user_shm_unlock(inode->i_size, ucounts); + info->flags &= ~SHMEM_F_LOCKED; + mapping_clear_unevictable(file->f_mapping); + } + retval = 0; + +out_nomem: + return retval; +} + +static int shmem_mmap_prepare(struct vm_area_desc *desc) +{ + struct file *file = desc->file; + struct inode *inode = file_inode(file); + + file_accessed(file); + /* This is anonymous shared memory if it is unlinked at the time of mmap */ + if (inode->i_nlink) + desc->vm_ops = &shmem_vm_ops; + else + desc->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 *); + +#if IS_ENABLED(CONFIG_UNICODE) +/* + * shmem_inode_casefold_flags - Deal with casefold file attribute flag + * + * The casefold file attribute needs some special checks. I can just be added to + * an empty dir, and can't be removed from a non-empty dir. + */ +static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags, + struct dentry *dentry, unsigned int *i_flags) +{ + unsigned int old = inode->i_flags; + struct super_block *sb = inode->i_sb; + + if (fsflags & FS_CASEFOLD_FL) { + if (!(old & S_CASEFOLD)) { + if (!sb->s_encoding) + return -EOPNOTSUPP; + + if (!S_ISDIR(inode->i_mode)) + return -ENOTDIR; + + if (dentry && !simple_empty(dentry)) + return -ENOTEMPTY; + } + + *i_flags = *i_flags | S_CASEFOLD; + } else if (old & S_CASEFOLD) { + if (dentry && !simple_empty(dentry)) + return -ENOTEMPTY; + } + + return 0; +} +#else +static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags, + struct dentry *dentry, unsigned int *i_flags) +{ + if (fsflags & FS_CASEFOLD_FL) + return -EOPNOTSUPP; + + return 0; +} +#endif + +/* + * chattr's fsflags are unrelated to extended attributes, + * but tmpfs has chosen to enable them under the same config option. + */ +static int shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry) +{ + unsigned int i_flags = 0; + int ret; + + ret = shmem_inode_casefold_flags(inode, fsflags, dentry, &i_flags); + if (ret) + return ret; + + 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 | S_CASEFOLD); + + return 0; +} +#else +static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry) +{ +} +#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, vma_flags_t 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); + INIT_LIST_HEAD_RCU(&info->xattrs); + spin_lock_init(&info->lock); + atomic_set(&info->stop_eviction, 0); + info->seals = F_SEAL_SEAL; + info->flags = vma_flags_test(&flags, VMA_NORESERVE_BIT) + ? SHMEM_F_NORESERVE : 0; + 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, NULL); + INIT_LIST_HEAD(&info->shrinklist); + INIT_LIST_HEAD(&info->swaplist); + 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, vma_flags_t 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 struct inode *shmem_get_inode(struct mnt_idmap *idmap, + struct super_block *sb, struct inode *dir, + umode_t mode, dev_t dev, vma_flags_t flags) +{ + return __shmem_get_inode(idmap, sb, dir, mode, dev, flags); +} +#endif /* CONFIG_TMPFS_QUOTA */ + +#ifdef CONFIG_USERFAULTFD +static struct folio *shmem_mfill_folio_alloc(struct vm_area_struct *vma, + unsigned long addr) +{ + struct inode *inode = file_inode(vma->vm_file); + struct address_space *mapping = inode->i_mapping; + struct shmem_inode_info *info = SHMEM_I(inode); + pgoff_t pgoff = linear_page_index(vma, addr); + gfp_t gfp = mapping_gfp_mask(mapping); + struct folio *folio; + + if (unlikely(pgoff >= DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE))) + return NULL; + + folio = shmem_alloc_folio(gfp, 0, info, pgoff); + if (!folio) + return NULL; + + if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) { + folio_put(folio); + return NULL; + } + + return folio; +} + +static int shmem_mfill_filemap_add(struct folio *folio, + struct vm_area_struct *vma, + unsigned long addr) +{ + struct inode *inode = file_inode(vma->vm_file); + struct address_space *mapping = inode->i_mapping; + pgoff_t pgoff = linear_page_index(vma, addr); + gfp_t gfp = mapping_gfp_mask(mapping); + int err; + + __folio_set_locked(folio); + __folio_set_swapbacked(folio); + + err = shmem_add_to_page_cache(folio, mapping, pgoff, NULL, gfp); + if (err) + goto err_unlock; + + if (shmem_inode_acct_blocks(inode, 1)) { + err = -ENOMEM; + goto err_delete_from_cache; + } + + folio_add_lru(folio); + shmem_recalc_inode(inode, 1, 0); + + return 0; + +err_delete_from_cache: + filemap_remove_folio(folio); +err_unlock: + folio_unlock(folio); + return err; +} + +static void shmem_mfill_filemap_remove(struct folio *folio, + struct vm_area_struct *vma) +{ + struct inode *inode = file_inode(vma->vm_file); + + filemap_remove_folio(folio); + shmem_recalc_inode(inode, 0, 0); + folio_unlock(folio); +} + +static struct folio *shmem_get_folio_noalloc(struct inode *inode, pgoff_t pgoff) +{ + struct folio *folio; + int err; + + err = shmem_get_folio(inode, pgoff, 0, &folio, SGP_NOALLOC); + if (err) + return ERR_PTR(err); + + return folio; +} + +static bool shmem_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags) +{ + return true; +} + +static const struct vm_uffd_ops shmem_uffd_ops = { + .can_userfault = shmem_can_userfault, + .get_folio_noalloc = shmem_get_folio_noalloc, + .alloc_folio = shmem_mfill_folio_alloc, + .filemap_add = shmem_mfill_filemap_add, + .filemap_remove = shmem_mfill_filemap_remove, +}; +#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(const struct kiocb *iocb, struct address_space *mapping, + loff_t pos, unsigned len, + struct folio **foliop, 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; + } + + if (unlikely((info->flags & SHMEM_F_MAPPING_FROZEN) && + pos + len > inode->i_size)) + return -EPERM; + + ret = shmem_get_folio(inode, index, pos + len, &folio, SGP_WRITE); + if (ret) + return ret; + + if (folio_contain_hwpoisoned_page(folio)) { + folio_unlock(folio); + folio_put(folio); + return -EIO; + } + + *foliop = folio; + return 0; +} + +static int +shmem_write_end(const struct kiocb *iocb, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct folio *folio, void *fsdata) +{ + 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; + + for (;;) { + struct folio *folio = NULL; + struct page *page = NULL; + unsigned long nr, ret; + loff_t end_offset, i_size = i_size_read(inode); + bool fallback_page_copy = false; + size_t fsize; + + if (unlikely(iocb->ki_pos >= i_size)) + break; + + index = iocb->ki_pos >> PAGE_SHIFT; + error = shmem_get_folio(inode, index, 0, &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; + } + + if (folio_test_large(folio) && + folio_test_has_hwpoisoned(folio)) + fallback_page_copy = true; + } + + /* + * We must evaluate after, since reads (unlike writes) + * are called without i_rwsem protection against truncate + */ + i_size = i_size_read(inode); + if (unlikely(iocb->ki_pos >= i_size)) { + if (folio) + folio_put(folio); + break; + } + end_offset = min_t(loff_t, i_size, iocb->ki_pos + to->count); + if (folio && likely(!fallback_page_copy)) + fsize = folio_size(folio); + else + fsize = PAGE_SIZE; + offset = iocb->ki_pos & (fsize - 1); + nr = min_t(loff_t, end_offset - iocb->ki_pos, fsize - 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)) { + if (likely(!fallback_page_copy)) + flush_dcache_folio(folio); + else + flush_dcache_page(page); + } + + /* + * Mark the folio 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... + */ + if (likely(!fallback_page_copy)) + ret = copy_folio_to_iter(folio, offset, nr, to); + else + 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; + iocb->ki_pos += ret; + + if (!iov_iter_count(to)) + break; + if (ret < nr) { + error = -EFAULT; + break; + } + cond_resched(); + } + + 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_is_full(pipe)) { + 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_buf_usage(pipe); + npages = max_t(ssize_t, pipe->max_usage - used, 0); + len = min_t(size_t, len, npages * PAGE_SIZE); + + do { + bool fallback_page_splice = false; + struct page *page = NULL; + pgoff_t index; + size_t size; + + if (*ppos >= i_size_read(inode)) + break; + + index = *ppos >> PAGE_SHIFT; + error = shmem_get_folio(inode, index, 0, &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)) { + error = -EIO; + break; + } + + if (folio_test_large(folio) && + folio_test_has_hwpoisoned(folio)) + fallback_page_splice = true; + } + + /* + * 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; + /* + * Fallback to PAGE_SIZE splice if the large folio has hwpoisoned + * pages. + */ + size = len; + if (unlikely(fallback_page_splice)) { + size_t offset = *ppos & ~PAGE_MASK; + + size = umin(size, PAGE_SIZE - offset); + } + part = min_t(loff_t, isize - *ppos, size); + + 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)) { + if (likely(!fallback_page_splice)) + flush_dcache_folio(folio); + else + flush_dcache_page(page); + } + 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_is_full(pipe)) + 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; + loff_t aligned_end; + int error; + + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) + return -EOPNOTSUPP; + + inode_lock(inode); + + if (info->flags & SHMEM_F_MAPPING_FROZEN) { + error = -EPERM; + goto out; + } + + 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); + WRITE_ONCE(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); + WRITE_ONCE(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; + } + + /* Check for wraparound */ + if (check_add_overflow(offset + len, (loff_t)PAGE_SIZE - 1, + &aligned_end)) { + error = -EFBIG; + goto out; + } + + start = offset >> PAGE_SHIFT; + end = aligned_end >> 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); + WRITE_ONCE(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, offset + len, + &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_writeout() 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); + WRITE_ONCE(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; + + if (!generic_ci_validate_strict_name(dir, &dentry->d_name)) + return -EINVAL; + + inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, + mk_vma_flags(VMA_NORESERVE_BIT)); + 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_make_persistent(dentry, inode); + 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, + mk_vma_flags(VMA_NORESERVE_BIT)); + 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 struct dentry *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 ERR_PTR(error); + inc_nlink(dir); + return NULL; +} + +static int shmem_create(struct mnt_idmap *idmap, struct inode *dir, + struct dentry *dentry, umode_t mode) +{ + 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; + + /* + * 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) + return ret; + } + + ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry); + if (ret) { + if (inode->i_nlink) + shmem_free_inode(inode->i_sb, 0); + return ret; + } + + dir->i_size += BOGO_DIRENT_SIZE; + inode_inc_iversion(dir); + return simple_link(old_dentry, dir, dentry); +} + +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_inc_iversion(dir); + simple_unlink(dir, dentry); + + /* + * For now, VFS can't deal with case-insensitive negative dentries, so + * we invalidate them + */ + if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir)) + d_invalidate(dentry); + + return 0; +} + +static int shmem_rmdir(struct inode *dir, struct dentry *dentry) +{ + if (!simple_empty(dentry)) + return -ENOTEMPTY; + + drop_nlink(d_inode(dentry)); + drop_nlink(dir); + return shmem_unlink(dir, dentry); +} + +static int shmem_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); + return error; +} + +/* + * 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); + bool had_offset = false; + 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_empty(new_dentry)) + return -ENOTEMPTY; + + error = simple_offset_add(shmem_get_offset_ctx(new_dir), new_dentry); + if (error == -EBUSY) + had_offset = true; + else if (unlikely(error)) + return error; + + if (flags & RENAME_WHITEOUT) { + error = shmem_whiteout(idmap, old_dir, old_dentry); + if (error) { + if (!had_offset) + simple_offset_remove(shmem_get_offset_ctx(new_dir), + new_dentry); + return error; + } + } + + simple_offset_rename(old_dir, old_dentry, new_dir, new_dentry); + 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; + char *link; + + len = strlen(symname) + 1; + if (len > PAGE_SIZE) + return -ENAMETOOLONG; + + inode = shmem_get_inode(idmap, dir->i_sb, dir, S_IFLNK | 0777, 0, + mk_vma_flags(VMA_NORESERVE_BIT)); + 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) { + link = kmemdup(symname, len, GFP_KERNEL); + if (!link) { + error = -ENOMEM; + goto out_remove_offset; + } + inode->i_op = &shmem_short_symlink_operations; + inode_set_cached_link(inode, link, len - 1); + } else { + inode_nohighmem(inode); + inode->i_mapping->a_ops = &shmem_aops; + error = shmem_get_folio(inode, 0, 0, &folio, SGP_WRITE); + if (error) + goto out_remove_offset; + inode->i_op = &shmem_symlink_inode_operations; + memcpy(folio_address(folio), symname, len); + folio_zero_range(folio, len, folio_size(folio) - 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_make_persistent(dentry, inode); + 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, 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 file_kattr *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 file_kattr *fa) +{ + struct inode *inode = d_inode(dentry); + struct shmem_inode_info *info = SHMEM_I(inode); + int ret, flags; + + if (fileattr_has_fsx(fa)) + return -EOPNOTSUPP; + if (fa->flags & ~SHMEM_FL_USER_MODIFIABLE) + return -EOPNOTSUPP; + + flags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) | + (fa->flags & SHMEM_FL_USER_MODIFIABLE); + + ret = shmem_set_inode_flags(inode, flags, dentry); + + if (ret) + return ret; + + info->fsflags = flags; + + 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; + size_t ispace = 0; + + 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++) { + CLASS(simple_xattr, new_xattr)(xattr->value, xattr->value_len); + if (IS_ERR(new_xattr)) + break; + + new_xattr->name = kasprintf(GFP_KERNEL_ACCOUNT, + XATTR_SECURITY_PREFIX "%s", xattr->name); + if (!new_xattr->name) + break; + + if (simple_xattr_add(&sbinfo->xa_cache, &info->xattrs, new_xattr)) + break; + + if (sbinfo->max_inodes) + ispace -= simple_xattr_space(new_xattr->name, new_xattr->size); + retain_and_null_ptr(new_xattr); + } + + if (xattr->name != NULL) { + if (ispace) { + raw_spin_lock(&sbinfo->stat_lock); + sbinfo->free_ispace += ispace; + raw_spin_unlock(&sbinfo->stat_lock); + } + return -ENOMEM; + } + WARN_ON(ispace); + + 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_sb_info *sbinfo = SHMEM_SB(inode->i_sb); + struct shmem_inode_info *info = SHMEM_I(inode); + + name = xattr_full_name(handler, name); + return simple_xattr_get(&sbinfo->xa_cache, &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(&sbinfo->xa_cache, &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_rcu(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, + Opt_casefold_version, + Opt_casefold, + Opt_strict_encoding, +}; + +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 + fsparam_string("casefold", Opt_casefold_version), + fsparam_flag ("casefold", Opt_casefold), + fsparam_flag ("strict_encoding", Opt_strict_encoding), + {} +}; + +#if IS_ENABLED(CONFIG_UNICODE) +static int shmem_parse_opt_casefold(struct fs_context *fc, struct fs_parameter *param, + bool latest_version) +{ + struct shmem_options *ctx = fc->fs_private; + int version = UTF8_LATEST; + struct unicode_map *encoding; + char *version_str = param->string + 5; + + if (!latest_version) { + if (strncmp(param->string, "utf8-", 5)) + return invalfc(fc, "Only UTF-8 encodings are supported " + "in the format: utf8-<version number>"); + + version = utf8_parse_version(version_str); + if (version < 0) + return invalfc(fc, "Invalid UTF-8 version: %s", version_str); + } + + encoding = utf8_load(version); + + if (IS_ERR(encoding)) { + return invalfc(fc, "Failed loading UTF-8 version: utf8-%u.%u.%u\n", + unicode_major(version), unicode_minor(version), + unicode_rev(version)); + } + + pr_info("tmpfs: Using encoding : utf8-%u.%u.%u\n", + unicode_major(version), unicode_minor(version), unicode_rev(version)); + + ctx->encoding = encoding; + + return 0; +} +#else +static int shmem_parse_opt_casefold(struct fs_context *fc, struct fs_parameter *param, + bool latest_version) +{ + return invalfc(fc, "tmpfs: Kernel not built with CONFIG_UNICODE\n"); +} +#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; + 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; + case Opt_casefold_version: + return shmem_parse_opt_casefold(fc, param, false); + case Opt_casefold: + return shmem_parse_opt_casefold(fc, param, true); + case Opt_strict_encoding: +#if IS_ENABLED(CONFIG_UNICODE) + ctx->strict_encoding = true; + break; +#else + return invalfc(fc, "tmpfs: Kernel not built with CONFIG_UNICODE\n"); +#endif + } + return 0; + +unsupported_parameter: + return invalfc(fc, "Unsupported parameter '%s'", param->key); +bad_value: + return invalfc(fc, "Bad value for '%s'", param->key); +} + +static char *shmem_next_opt(char **s) +{ + char *sbegin = *s; + char *p; + + if (sbegin == NULL) + return NULL; + + /* + * NUL-terminate this option: unfortunately, + * mount options form a comma-separated list, + * but mpol's nodelist may also contain commas. + */ + for (;;) { + p = strchr(*s, ','); + if (p == NULL) + break; + *s = p + 1; + if (!isdigit(*(p+1))) { + *p = '\0'; + return sbegin; + } + } + + *s = NULL; + return sbegin; +} + +static int shmem_parse_monolithic(struct fs_context *fc, void *data) +{ + return vfs_parse_monolithic_sep(fc, data, shmem_next_opt); +} + +/* + * 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; + } + + /* + * "noswap" doesn't use fsparam_flag_no, i.e. there's no "swap" + * counterpart for (re-)enabling swap. + */ + if (ctx->noswap && !sbinfo->noswap) { + err = "Cannot disable swap on remount"; + 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); + +#if IS_ENABLED(CONFIG_UNICODE) + if (sb->s_encoding) + utf8_unload(sb->s_encoding); +#endif + +#ifdef CONFIG_TMPFS_QUOTA + shmem_disable_quotas(sb); +#endif + free_percpu(sbinfo->ino_batch); + percpu_counter_destroy(&sbinfo->used_blocks); + mpol_put(sbinfo->mpol); +#ifdef CONFIG_TMPFS_XATTR + simple_xattr_cache_cleanup(&sbinfo->xa_cache); +#endif + kfree(sbinfo); + sb->s_fs_info = NULL; +} + +#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_TMPFS) +static const struct dentry_operations shmem_ci_dentry_ops = { + .d_hash = generic_ci_d_hash, + .d_compare = generic_ci_d_compare, +}; +#endif + +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; + +#if IS_ENABLED(CONFIG_UNICODE) + if (!ctx->encoding && ctx->strict_encoding) { + pr_err("tmpfs: strict_encoding option without encoding is forbidden\n"); + error = -EINVAL; + goto failed; + } + + if (ctx->encoding) { + sb->s_encoding = ctx->encoding; + set_default_d_op(sb, &shmem_ci_dentry_ops); + if (ctx->strict_encoding) + sb->s_encoding_flags = SB_ENC_STRICT_MODE_FL; + } +#endif + +#else + sb->s_flags |= SB_NOUSER; +#endif /* CONFIG_TMPFS */ + sb->s_d_flags |= DCACHE_DONTCACHE; + 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; +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + if (ctx->seen & SHMEM_SEEN_HUGE) + sbinfo->huge = ctx->huge; + else + sbinfo->huge = tmpfs_huge; +#endif + 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, + mk_vma_flags(VMA_NORESERVE_BIT)); + 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_monolithic, + .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 = { + .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_prepare = shmem_mmap_prepare, + .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, + .setlease = generic_setlease, +#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 = inode_just_drop, + .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 +#ifdef CONFIG_USERFAULTFD + .uffd_ops = &shmem_uffd_ops, +#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 +#ifdef CONFIG_USERFAULTFD + .uffd_ops = &shmem_uffd_ops, +#endif +}; + +int shmem_init_fs_context(struct fs_context *fc) +{ + struct shmem_options *ctx; + + ctx = kzalloc_obj(struct shmem_options); + if (!ctx) + return -ENOMEM; + + ctx->mode = 0777 | S_ISVTX; + ctx->uid = current_fsuid(); + ctx->gid = current_fsgid(); + +#if IS_ENABLED(CONFIG_UNICODE) + ctx->encoding = NULL; +#endif + + fc->fs_private = ctx; + fc->ops = &shmem_fs_context_ops; +#ifdef CONFIG_TMPFS + fc->sb_flags |= SB_I_VERSION; +#endif + 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_anon_super, + .fs_flags = FS_USERNS_MOUNT | FS_ALLOW_IDMAP | FS_MGTIME, +}; + +#if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS) + +#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store) \ +{ \ + .attr = { .name = __stringify(_name), .mode = _mode }, \ + .show = _show, \ + .store = _store, \ +} + +#define TMPFS_ATTR_W(_name, _store) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0200, NULL, _store) + +#define TMPFS_ATTR_RW(_name, _show, _store) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0644, _show, _store) + +#define TMPFS_ATTR_RO(_name, _show) \ + static struct kobj_attribute tmpfs_attr_##_name = \ + __INIT_KOBJ_ATTR(_name, 0444, _show, NULL) + +#if IS_ENABLED(CONFIG_UNICODE) +static ssize_t casefold_show(struct kobject *kobj, struct kobj_attribute *a, + char *buf) +{ + return sysfs_emit(buf, "supported\n"); +} +TMPFS_ATTR_RO(casefold, casefold_show); +#endif + +static struct attribute *tmpfs_attributes[] = { +#if IS_ENABLED(CONFIG_UNICODE) + &tmpfs_attr_casefold.attr, +#endif + NULL +}; + +static const struct attribute_group tmpfs_attribute_group = { + .attrs = tmpfs_attributes, + .name = "features" +}; + +static struct kobject *tmpfs_kobj; + +static int __init tmpfs_sysfs_init(void) +{ + int ret; + + tmpfs_kobj = kobject_create_and_add("tmpfs", fs_kobj); + if (!tmpfs_kobj) + return -ENOMEM; + + ret = sysfs_create_group(tmpfs_kobj, &tmpfs_attribute_group); + if (ret) + kobject_put(tmpfs_kobj); + + return ret; +} +#endif /* CONFIG_SYSFS && CONFIG_TMPFS */ + +void __init shmem_init(void) +{ + int error; + + shmem_init_inodecache(); + +#ifdef CONFIG_TMPFS_QUOTA + register_quota_format(&shmem_quota_format); +#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; + } + +#if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS) + error = tmpfs_sysfs_init(); + if (error) { + pr_err("Could not init tmpfs sysfs\n"); + goto out1; + } +#endif + +#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. + */ + if (!shmem_orders_configured) + 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); +#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, err; + + 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 huge; + + shmem_huge = huge; + if (shmem_huge > SHMEM_HUGE_DENY) + SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; + + err = start_stop_khugepaged(); + return err ? err : count; +} + +struct kobj_attribute shmem_enabled_attr = __ATTR_RW(shmem_enabled); +static DEFINE_SPINLOCK(huge_shmem_orders_lock); + +enum huge_mode { + HUGE_SHMEM_ENABLED_ALWAYS = 0, + HUGE_SHMEM_ENABLED_INHERIT, + HUGE_SHMEM_ENABLED_WITHIN_SIZE, + HUGE_SHMEM_ENABLED_ADVISE, + HUGE_SHMEM_ENABLED_NEVER, +}; + +static const char * const huge_mode_strings[] = { + [HUGE_SHMEM_ENABLED_ALWAYS] = "always", + [HUGE_SHMEM_ENABLED_INHERIT] = "inherit", + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = "within_size", + [HUGE_SHMEM_ENABLED_ADVISE] = "advise", + [HUGE_SHMEM_ENABLED_NEVER] = "never", +}; + +static unsigned long * const huge_mode_orders[] = { + [HUGE_SHMEM_ENABLED_ALWAYS] = &huge_shmem_orders_always, + [HUGE_SHMEM_ENABLED_INHERIT] = &huge_shmem_orders_inherit, + [HUGE_SHMEM_ENABLED_WITHIN_SIZE] = &huge_shmem_orders_within_size, + [HUGE_SHMEM_ENABLED_ADVISE] = &huge_shmem_orders_madvise, +}; + +static ssize_t thpsize_shmem_enabled_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + int order = to_thpsize(kobj)->order; + int active = HUGE_SHMEM_ENABLED_NEVER; + int len = 0; + int i; + + for (i = 0; i < ARRAY_SIZE(huge_mode_orders); i++) { + if (test_bit(order, huge_mode_orders[i])) { + active = i; + break; + } + } + + for (i = 0; i < ARRAY_SIZE(huge_mode_strings); i++) { + if (i == active) + len += sysfs_emit_at(buf, len, "[%s] ", + huge_mode_strings[i]); + else + len += sysfs_emit_at(buf, len, "%s ", + huge_mode_strings[i]); + } + + /* Replace trailing space with newline */ + buf[len - 1] = '\n'; + + return len; +} + +static bool set_shmem_enabled_mode(int order, enum huge_mode mode) +{ + bool changed = false; + enum huge_mode idx; + + spin_lock(&huge_shmem_orders_lock); + for (idx = 0; idx < ARRAY_SIZE(huge_mode_orders); idx++) { + if (idx == mode) + changed |= !__test_and_set_bit(order, huge_mode_orders[idx]); + else + changed |= __test_and_clear_bit(order, huge_mode_orders[idx]); + } + spin_unlock(&huge_shmem_orders_lock); + + return changed; +} + +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; + int mode; + + mode = sysfs_match_string(huge_mode_strings, buf); + if (mode < 0) + return mode; + + /* Do not override huge allocation policy with non-PMD sized mTHP */ + if (mode == HUGE_SHMEM_ENABLED_INHERIT && + shmem_huge == SHMEM_HUGE_FORCE && !is_pmd_order(order)) + return -EINVAL; + + if (set_shmem_enabled_mode(order, mode)) { + int err = start_stop_khugepaged(); + if (err) + return err; + } else { + /* + * Recalculate watermarks even when the mode hasn't changed + * to preserve the legacy behavior, as this is always called + * inside start_stop_khugepaged(). + */ + set_recommended_min_free_kbytes(); + } + + return count; +} + +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 */ + +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) + +static int __init setup_transparent_hugepage_shmem(char *str) +{ + int huge; + + huge = shmem_parse_huge(str); + if (huge == -EINVAL) { + pr_warn("transparent_hugepage_shmem= cannot parse, ignored\n"); + return huge; + } + + shmem_huge = huge; + return 1; +} +__setup("transparent_hugepage_shmem=", setup_transparent_hugepage_shmem); + +static int __init setup_transparent_hugepage_tmpfs(char *str) +{ + int huge; + + huge = shmem_parse_huge(str); + if (huge < 0) { + pr_warn("transparent_hugepage_tmpfs= cannot parse, ignored\n"); + return huge; + } + + tmpfs_huge = huge; + return 1; +} +__setup("transparent_hugepage_tmpfs=", setup_transparent_hugepage_tmpfs); + +static char str_dup[PAGE_SIZE] __initdata; +static int __init setup_thp_shmem(char *str) +{ + char *token, *range, *policy, *subtoken; + unsigned long always, inherit, madvise, within_size; + char *start_size, *end_size; + int start, end, nr; + char *p; + + if (!str || strlen(str) + 1 > PAGE_SIZE) + goto err; + strscpy(str_dup, str); + + always = huge_shmem_orders_always; + inherit = huge_shmem_orders_inherit; + madvise = huge_shmem_orders_madvise; + within_size = huge_shmem_orders_within_size; + p = str_dup; + while ((token = strsep(&p, ";")) != NULL) { + range = strsep(&token, ":"); + policy = token; + + if (!policy) + goto err; + + while ((subtoken = strsep(&range, ",")) != NULL) { + if (strchr(subtoken, '-')) { + start_size = strsep(&subtoken, "-"); + end_size = subtoken; + + start = get_order_from_str(start_size, + THP_ORDERS_ALL_FILE_DEFAULT); + end = get_order_from_str(end_size, + THP_ORDERS_ALL_FILE_DEFAULT); + } else { + start_size = end_size = subtoken; + start = end = get_order_from_str(subtoken, + THP_ORDERS_ALL_FILE_DEFAULT); + } + + if (start < 0) { + pr_err("invalid size %s in thp_shmem boot parameter\n", + start_size); + goto err; + } + + if (end < 0) { + pr_err("invalid size %s in thp_shmem boot parameter\n", + end_size); + goto err; + } + + if (start > end) + goto err; + + nr = end - start + 1; + if (!strcmp(policy, "always")) { + bitmap_set(&always, start, nr); + bitmap_clear(&inherit, start, nr); + bitmap_clear(&madvise, start, nr); + bitmap_clear(&within_size, start, nr); + } else if (!strcmp(policy, "advise")) { + bitmap_set(&madvise, start, nr); + bitmap_clear(&inherit, start, nr); + bitmap_clear(&always, start, nr); + bitmap_clear(&within_size, start, nr); + } else if (!strcmp(policy, "inherit")) { + bitmap_set(&inherit, start, nr); + bitmap_clear(&madvise, start, nr); + bitmap_clear(&always, start, nr); + bitmap_clear(&within_size, start, nr); + } else if (!strcmp(policy, "within_size")) { + bitmap_set(&within_size, start, nr); + bitmap_clear(&inherit, start, nr); + bitmap_clear(&madvise, start, nr); + bitmap_clear(&always, start, nr); + } else if (!strcmp(policy, "never")) { + bitmap_clear(&inherit, start, nr); + bitmap_clear(&madvise, start, nr); + bitmap_clear(&always, start, nr); + bitmap_clear(&within_size, start, nr); + } else { + pr_err("invalid policy %s in thp_shmem boot parameter\n", policy); + goto err; + } + } + } + + huge_shmem_orders_always = always; + huge_shmem_orders_madvise = madvise; + huge_shmem_orders_inherit = inherit; + huge_shmem_orders_within_size = within_size; + shmem_orders_configured = true; + return 1; + +err: + pr_warn("thp_shmem=%s: error parsing string, ignoring setting\n", str); + return 0; +} +__setup("thp_shmem=", setup_thp_shmem); + +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +#else /* !CONFIG_SHMEM */ + +/* + * tiny-shmem: simple shmemfs and tmpfs using ramfs code + * + * This is intended for small system where the benefits of the full + * shmem code (swap-backed and resource-limited) are outweighed by + * their complexity. On systems without swap this code should be + * effectively equivalent, but much lighter weight. + */ + +static struct file_system_type shmem_fs_type = { + .name = "tmpfs", + .init_fs_context = ramfs_init_fs_context, + .parameters = ramfs_fs_parameters, + .kill_sb = 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(file, addr, len, pgoff, flags); +} +#endif + +void shmem_truncate_range(struct inode *inode, loff_t lstart, uoff_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 + +static inline int shmem_acct_size(unsigned long flags, loff_t size) +{ + return 0; +} + +static inline void shmem_unacct_size(unsigned long flags, loff_t size) +{ +} + +static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap, + struct super_block *sb, struct inode *dir, + umode_t mode, dev_t dev, vma_flags_t 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, vma_flags_t flags, + unsigned int i_flags) +{ + const unsigned long shmem_flags = + vma_flags_test(&flags, VMA_NORESERVE_BIT) ? SHMEM_F_NORESERVE : 0; + 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 (is_idmapped_mnt(mnt)) + return ERR_PTR(-EINVAL); + + if (shmem_acct_size(shmem_flags, size)) + return ERR_PTR(-ENOMEM); + + inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL, + S_IFREG | S_IRWXUGO, 0, flags); + if (IS_ERR(inode)) { + shmem_unacct_size(shmem_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: VMA_NORESERVE_BIT suppresses pre-accounting of the entire object size + */ +struct file *shmem_kernel_file_setup(const char *name, loff_t size, + vma_flags_t 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: VMA_NORESERVE_BIT suppresses pre-accounting of the entire object size + */ +struct file *shmem_file_setup(const char *name, loff_t size, vma_flags_t 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: VMA_NORESERVE_BIT suppresses pre-accounting of the entire object size + */ +struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, const char *name, + loff_t size, vma_flags_t flags) +{ + return __shmem_file_setup(mnt, name, size, flags, 0); +} +EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt); + +static struct file *__shmem_zero_setup(unsigned long start, unsigned long end, + vma_flags_t flags) +{ + loff_t size = end - 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(). + */ + return shmem_kernel_file_setup("dev/zero", size, flags); +} + +/** + * shmem_zero_setup - setup a shared anonymous mapping + * @vma: the vma to be mmapped is prepared by do_mmap + * Returns: 0 on success, or error + */ +int shmem_zero_setup(struct vm_area_struct *vma) +{ + struct file *file = __shmem_zero_setup(vma->vm_start, vma->vm_end, vma->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_zero_setup_desc - same as shmem_zero_setup, but determined by VMA + * descriptor for convenience. + * @desc: Describes VMA + * Returns: 0 on success, or error + */ +int shmem_zero_setup_desc(struct vm_area_desc *desc) +{ + struct file *file = __shmem_zero_setup(desc->start, desc->end, desc->vma_flags); + + if (IS_ERR(file)) + return PTR_ERR(file); + + desc->vm_file = file; + desc->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, i_size_read(inode), + &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); |