1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __SHMEM_FS_H 3 #define __SHMEM_FS_H 4 5 #include <linux/file.h> 6 #include <linux/swap.h> 7 #include <linux/mempolicy.h> 8 #include <linux/pagemap.h> 9 #include <linux/percpu_counter.h> 10 #include <linux/xattr.h> 11 #include <linux/fs_parser.h> 12 #include <linux/userfaultfd_k.h> 13 #include <linux/bits.h> 14 15 struct swap_iocb; 16 17 /* inode in-kernel data */ 18 19 #ifdef CONFIG_TMPFS_QUOTA 20 #define SHMEM_MAXQUOTAS 2 21 #endif 22 23 /* Suppress pre-accounting of the entire object size. */ 24 #define SHMEM_F_NORESERVE BIT(0) 25 /* Disallow swapping. */ 26 #define SHMEM_F_LOCKED BIT(1) 27 /* 28 * Disallow growing, shrinking, or hole punching in the inode. Combined with 29 * folio pinning, makes sure the inode's mapping stays fixed. 30 * 31 * In some ways similar to F_SEAL_GROW | F_SEAL_SHRINK, but can be removed and 32 * isn't directly visible to userspace. 33 */ 34 #define SHMEM_F_MAPPING_FROZEN BIT(2) 35 36 struct shmem_inode_info { 37 spinlock_t lock; 38 unsigned int seals; /* shmem seals */ 39 unsigned long flags; 40 unsigned long alloced; /* data pages alloced to file */ 41 unsigned long swapped; /* subtotal assigned to swap */ 42 union { 43 struct offset_ctx dir_offsets; /* stable directory offsets */ 44 struct { 45 struct list_head shrinklist; /* shrinkable hpage inodes */ 46 struct list_head swaplist; /* chain of maybes on swap */ 47 }; 48 }; 49 struct timespec64 i_crtime; /* file creation time */ 50 struct shared_policy policy; /* NUMA memory alloc policy */ 51 struct simple_xattrs *xattrs; /* list of xattrs */ 52 pgoff_t fallocend; /* highest fallocate endindex */ 53 unsigned int fsflags; /* for FS_IOC_[SG]ETFLAGS */ 54 atomic_t stop_eviction; /* hold when working on inode */ 55 #ifdef CONFIG_TMPFS_QUOTA 56 struct dquot __rcu *i_dquot[MAXQUOTAS]; 57 #endif 58 struct inode vfs_inode; 59 }; 60 61 #define SHMEM_FL_USER_VISIBLE (FS_FL_USER_VISIBLE | FS_CASEFOLD_FL) 62 #define SHMEM_FL_USER_MODIFIABLE \ 63 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL) 64 #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL) 65 66 struct shmem_quota_limits { 67 qsize_t usrquota_bhardlimit; /* Default user quota block hard limit */ 68 qsize_t usrquota_ihardlimit; /* Default user quota inode hard limit */ 69 qsize_t grpquota_bhardlimit; /* Default group quota block hard limit */ 70 qsize_t grpquota_ihardlimit; /* Default group quota inode hard limit */ 71 }; 72 73 struct shmem_sb_info { 74 unsigned long max_blocks; /* How many blocks are allowed */ 75 struct percpu_counter used_blocks; /* How many are allocated */ 76 unsigned long max_inodes; /* How many inodes are allowed */ 77 unsigned long free_ispace; /* How much ispace left for allocation */ 78 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */ 79 umode_t mode; /* Mount mode for root directory */ 80 unsigned char huge; /* Whether to try for hugepages */ 81 kuid_t uid; /* Mount uid for root directory */ 82 kgid_t gid; /* Mount gid for root directory */ 83 bool full_inums; /* If i_ino should be uint or ino_t */ 84 bool noswap; /* ignores VM reclaim / swap requests */ 85 ino_t next_ino; /* The next per-sb inode number to use */ 86 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */ 87 struct mempolicy *mpol; /* default memory policy for mappings */ 88 spinlock_t shrinklist_lock; /* Protects shrinklist */ 89 struct list_head shrinklist; /* List of shinkable inodes */ 90 unsigned long shrinklist_len; /* Length of shrinklist */ 91 struct shmem_quota_limits qlimits; /* Default quota limits */ 92 }; 93 94 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode) 95 { 96 return container_of(inode, struct shmem_inode_info, vfs_inode); 97 } 98 99 /* 100 * Functions in mm/shmem.c called directly from elsewhere: 101 */ 102 extern const struct fs_parameter_spec shmem_fs_parameters[]; 103 extern void shmem_init(void); 104 extern int shmem_init_fs_context(struct fs_context *fc); 105 struct file *shmem_file_setup(const char *name, loff_t size, vma_flags_t flags); 106 struct file *shmem_kernel_file_setup(const char *name, loff_t size, vma_flags_t vma_flags); 107 extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt, 108 const char *name, loff_t size, vma_flags_t flags); 109 int shmem_zero_setup(struct vm_area_struct *vma); 110 int shmem_zero_setup_desc(struct vm_area_desc *desc); 111 extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr, 112 unsigned long len, unsigned long pgoff, unsigned long flags); 113 extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts); 114 #ifdef CONFIG_SHMEM 115 bool shmem_mapping(const struct address_space *mapping); 116 #else 117 static inline bool shmem_mapping(const struct address_space *mapping) 118 { 119 return false; 120 } 121 #endif /* CONFIG_SHMEM */ 122 void shmem_unlock_mapping(struct address_space *mapping); 123 struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, 124 pgoff_t index, gfp_t gfp_mask); 125 int shmem_writeout(struct folio *folio, struct swap_iocb **plug, 126 struct list_head *folio_list); 127 void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end); 128 int shmem_unuse(unsigned int type); 129 130 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 131 unsigned long shmem_allowable_huge_orders(struct inode *inode, 132 struct vm_area_struct *vma, pgoff_t index, 133 loff_t write_end, bool shmem_huge_force); 134 bool shmem_hpage_pmd_enabled(void); 135 #else 136 static inline unsigned long shmem_allowable_huge_orders(struct inode *inode, 137 struct vm_area_struct *vma, pgoff_t index, 138 loff_t write_end, bool shmem_huge_force) 139 { 140 return 0; 141 } 142 143 static inline bool shmem_hpage_pmd_enabled(void) 144 { 145 return false; 146 } 147 #endif 148 149 #ifdef CONFIG_SHMEM 150 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma); 151 extern void shmem_uncharge(struct inode *inode, long pages); 152 #else 153 static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma) 154 { 155 return 0; 156 } 157 158 static inline void shmem_uncharge(struct inode *inode, long pages) 159 { 160 } 161 #endif 162 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping, 163 pgoff_t start, pgoff_t end); 164 165 /* Flag allocation requirements to shmem_get_folio */ 166 enum sgp_type { 167 SGP_READ, /* don't exceed i_size, don't allocate page */ 168 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */ 169 SGP_CACHE, /* don't exceed i_size, may allocate page */ 170 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ 171 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ 172 }; 173 174 int shmem_get_folio(struct inode *inode, pgoff_t index, loff_t write_end, 175 struct folio **foliop, enum sgp_type sgp); 176 struct folio *shmem_read_folio_gfp(struct address_space *mapping, 177 pgoff_t index, gfp_t gfp); 178 179 static inline struct folio *shmem_read_folio(struct address_space *mapping, 180 pgoff_t index) 181 { 182 return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping)); 183 } 184 185 static inline struct page *shmem_read_mapping_page( 186 struct address_space *mapping, pgoff_t index) 187 { 188 return shmem_read_mapping_page_gfp(mapping, index, 189 mapping_gfp_mask(mapping)); 190 } 191 192 static inline bool shmem_file(struct file *file) 193 { 194 if (!IS_ENABLED(CONFIG_SHMEM)) 195 return false; 196 if (!file || !file->f_mapping) 197 return false; 198 return shmem_mapping(file->f_mapping); 199 } 200 201 /* Must be called with inode lock taken exclusive. */ 202 static inline void shmem_freeze(struct inode *inode, bool freeze) 203 { 204 if (freeze) 205 SHMEM_I(inode)->flags |= SHMEM_F_MAPPING_FROZEN; 206 else 207 SHMEM_I(inode)->flags &= ~SHMEM_F_MAPPING_FROZEN; 208 } 209 210 /* 211 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages 212 * beyond i_size's notion of EOF, which fallocate has committed to reserving: 213 * which split_huge_page() must therefore not delete. This use of a single 214 * "fallocend" per inode errs on the side of not deleting a reservation when 215 * in doubt: there are plenty of cases when it preserves unreserved pages. 216 */ 217 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof) 218 { 219 return max(eof, SHMEM_I(inode)->fallocend); 220 } 221 222 extern bool shmem_charge(struct inode *inode, long pages); 223 224 #ifdef CONFIG_USERFAULTFD 225 #ifdef CONFIG_SHMEM 226 extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd, 227 struct vm_area_struct *dst_vma, 228 unsigned long dst_addr, 229 unsigned long src_addr, 230 uffd_flags_t flags, 231 struct folio **foliop); 232 #else /* !CONFIG_SHMEM */ 233 #define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \ 234 src_addr, flags, foliop) ({ BUG(); 0; }) 235 #endif /* CONFIG_SHMEM */ 236 #endif /* CONFIG_USERFAULTFD */ 237 238 /* 239 * Used space is stored as unsigned 64-bit value in bytes but 240 * quota core supports only signed 64-bit values so use that 241 * as a limit 242 */ 243 #define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */ 244 #define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL 245 246 #ifdef CONFIG_TMPFS_QUOTA 247 extern const struct dquot_operations shmem_quota_operations; 248 extern struct quota_format_type shmem_quota_format; 249 #endif /* CONFIG_TMPFS_QUOTA */ 250 251 #endif 252