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