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
20struct 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 *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
50struct 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
57struct 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
78static 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 */
86extern const struct fs_parameter_spec shmem_fs_parameters[];
87extern void shmem_init(void);
88extern int shmem_init_fs_context(struct fs_context *fc);
89extern struct file *shmem_file_setup(const char *name,
90 loff_t size, unsigned long flags);
91extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
92 unsigned long flags);
93extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
94 const char *name, loff_t size, unsigned long flags);
95extern int shmem_zero_setup(struct vm_area_struct *);
96extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
97 unsigned long len, unsigned long pgoff, unsigned long flags);
98extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
99#ifdef CONFIG_SHMEM
100extern const struct address_space_operations shmem_aops;
101static inline bool shmem_mapping(struct address_space *mapping)
102{
103 return mapping->a_ops == &shmem_aops;
104}
105#else
106static inline bool shmem_mapping(struct address_space *mapping)
107{
108 return false;
109}
110#endif /* CONFIG_SHMEM */
111extern void shmem_unlock_mapping(struct address_space *mapping);
112extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
113 pgoff_t index, gfp_t gfp_mask);
114extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
115int shmem_unuse(unsigned int type);
116
117extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
118 struct mm_struct *mm, unsigned long vm_flags);
119#ifdef CONFIG_SHMEM
120extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
121#else
122static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
123{
124 return 0;
125}
126#endif
127extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
128 pgoff_t start, pgoff_t end);
129
130/* Flag allocation requirements to shmem_get_folio */
131enum sgp_type {
132 SGP_READ, /* don't exceed i_size, don't allocate page */
133 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
134 SGP_CACHE, /* don't exceed i_size, may allocate page */
135 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
136 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
137};
138
139int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
140 enum sgp_type sgp);
141struct folio *shmem_read_folio_gfp(struct address_space *mapping,
142 pgoff_t index, gfp_t gfp);
143
144static inline struct folio *shmem_read_folio(struct address_space *mapping,
145 pgoff_t index)
146{
147 return shmem_read_folio_gfp(mapping, index, gfp: mapping_gfp_mask(mapping));
148}
149
150static inline struct page *shmem_read_mapping_page(
151 struct address_space *mapping, pgoff_t index)
152{
153 return shmem_read_mapping_page_gfp(mapping, index,
154 gfp_mask: mapping_gfp_mask(mapping));
155}
156
157static inline bool shmem_file(struct file *file)
158{
159 if (!IS_ENABLED(CONFIG_SHMEM))
160 return false;
161 if (!file || !file->f_mapping)
162 return false;
163 return shmem_mapping(mapping: file->f_mapping);
164}
165
166/*
167 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
168 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
169 * which split_huge_page() must therefore not delete. This use of a single
170 * "fallocend" per inode errs on the side of not deleting a reservation when
171 * in doubt: there are plenty of cases when it preserves unreserved pages.
172 */
173static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
174{
175 return max(eof, SHMEM_I(inode)->fallocend);
176}
177
178extern bool shmem_charge(struct inode *inode, long pages);
179extern void shmem_uncharge(struct inode *inode, long pages);
180
181#ifdef CONFIG_USERFAULTFD
182#ifdef CONFIG_SHMEM
183extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
184 struct vm_area_struct *dst_vma,
185 unsigned long dst_addr,
186 unsigned long src_addr,
187 uffd_flags_t flags,
188 struct folio **foliop);
189#else /* !CONFIG_SHMEM */
190#define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
191 src_addr, flags, foliop) ({ BUG(); 0; })
192#endif /* CONFIG_SHMEM */
193#endif /* CONFIG_USERFAULTFD */
194
195/*
196 * Used space is stored as unsigned 64-bit value in bytes but
197 * quota core supports only signed 64-bit values so use that
198 * as a limit
199 */
200#define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */
201#define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL
202
203#ifdef CONFIG_TMPFS_QUOTA
204extern const struct dquot_operations shmem_quota_operations;
205extern struct quota_format_type shmem_quota_format;
206#endif /* CONFIG_TMPFS_QUOTA */
207
208#endif
209

source code of linux/include/linux/shmem_fs.h