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