include/linux/shmem_fs.h

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