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
46 #define SHMEM_FL_USER_MODIFIABLE \
47 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL)
48 #define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_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 extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
115 struct mm_struct *mm, unsigned long vm_flags);
116 unsigned long shmem_allowable_huge_orders(struct inode *inode,
117 struct vm_area_struct *vma, pgoff_t index,
118 bool global_huge);
119 #else
120 static __always_inline bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
121 struct mm_struct *mm, unsigned long vm_flags)
122 {
123 return false;
124 }
125 static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
126 struct vm_area_struct *vma, pgoff_t index,
127 bool global_huge)
128 {
129 return 0;
130 }
131 #endif
132
133 #ifdef CONFIG_SHMEM
134 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
135 #else
136 static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
137 {
138 return 0;
139 }
140 #endif
141 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
142 pgoff_t start, pgoff_t end);
143
144 /* Flag allocation requirements to shmem_get_folio */
145 enum sgp_type {
146 SGP_READ, /* don't exceed i_size, don't allocate page */
147 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
148 SGP_CACHE, /* don't exceed i_size, may allocate page */
149 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
150 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
151 };
152
153 int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
154 enum sgp_type sgp);
155 struct folio *shmem_read_folio_gfp(struct address_space *mapping,
156 pgoff_t index, gfp_t gfp);
157
158 static inline struct folio *shmem_read_folio(struct address_space *mapping,
159 pgoff_t index)
160 {
161 return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping));
162 }
163
164 static inline struct page *shmem_read_mapping_page(
165 struct address_space *mapping, pgoff_t index)
166 {
167 return shmem_read_mapping_page_gfp(mapping, index,
168 mapping_gfp_mask(mapping));
169 }
170
171 static inline bool shmem_file(struct file *file)
172 {
173 if (!IS_ENABLED(CONFIG_SHMEM))
174 return false;
175 if (!file || !file->f_mapping)
176 return false;
177 return shmem_mapping(file->f_mapping);
178 }
179
180 /*
181 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
182 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
183 * which split_huge_page() must therefore not delete. This use of a single
184 * "fallocend" per inode errs on the side of not deleting a reservation when
185 * in doubt: there are plenty of cases when it preserves unreserved pages.
186 */
187 static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
188 {
189 return max(eof, SHMEM_I(inode)->fallocend);
190 }
191
192 extern bool shmem_charge(struct inode *inode, long pages);
193 extern void shmem_uncharge(struct inode *inode, long pages);
194
195 #ifdef CONFIG_USERFAULTFD
196 #ifdef CONFIG_SHMEM
197 extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
198 struct vm_area_struct *dst_vma,
199 unsigned long dst_addr,
200 unsigned long src_addr,
201 uffd_flags_t flags,
202 struct folio **foliop);
203 #else /* !CONFIG_SHMEM */
204 #define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
205 src_addr, flags, foliop) ({ BUG(); 0; })
206 #endif /* CONFIG_SHMEM */
207 #endif /* CONFIG_USERFAULTFD */
208
209 /*
210 * Used space is stored as unsigned 64-bit value in bytes but
211 * quota core supports only signed 64-bit values so use that
212 * as a limit
213 */
214 #define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */
215 #define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL
216
217 #ifdef CONFIG_TMPFS_QUOTA
218 extern const struct dquot_operations shmem_quota_operations;
219 extern struct quota_format_type shmem_quota_format;
220 #endif /* CONFIG_TMPFS_QUOTA */
221
222 #endif
223
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