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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
15struct swap_iocb;
16
17/* inode in-kernel data */
18
19#ifdef CONFIG_TMPFS_QUOTA
20#define SHMEM_MAXQUOTAS 2
21#endif
22
23/* Suppress pre-accounting of the entire object size. */
24#define SHMEM_F_NORESERVE BIT(0)
25/* Disallow swapping. */
26#define SHMEM_F_LOCKED BIT(1)
27/*
28 * Disallow growing, shrinking, or hole punching in the inode. Combined with
29 * folio pinning, makes sure the inode's mapping stays fixed.
30 *
31 * In some ways similar to F_SEAL_GROW | F_SEAL_SHRINK, but can be removed and
32 * isn't directly visible to userspace.
33 */
34#define SHMEM_F_MAPPING_FROZEN BIT(2)
35
36struct shmem_inode_info {
37 spinlock_t lock;
38 unsigned int seals; /* shmem seals */
39 unsigned long flags;
40 unsigned long alloced; /* data pages alloced to file */
41 unsigned long swapped; /* subtotal assigned to swap */
42 union {
43 struct offset_ctx dir_offsets; /* stable directory offsets */
44 struct {
45 struct list_head shrinklist; /* shrinkable hpage inodes */
46 struct list_head swaplist; /* chain of maybes on swap */
47 };
48 };
49 struct timespec64 i_crtime; /* file creation time */
50 struct shared_policy policy; /* NUMA memory alloc policy */
51 struct simple_xattrs xattrs; /* list of xattrs */
52 pgoff_t fallocend; /* highest fallocate endindex */
53 unsigned int fsflags; /* for FS_IOC_[SG]ETFLAGS */
54 atomic_t stop_eviction; /* hold when working on inode */
55#ifdef CONFIG_TMPFS_QUOTA
56 struct dquot __rcu *i_dquot[MAXQUOTAS];
57#endif
58 struct inode vfs_inode;
59};
60
61#define SHMEM_FL_USER_VISIBLE (FS_FL_USER_VISIBLE | FS_CASEFOLD_FL)
62#define SHMEM_FL_USER_MODIFIABLE \
63 (FS_IMMUTABLE_FL | FS_APPEND_FL | FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL)
64#define SHMEM_FL_INHERITED (FS_NODUMP_FL | FS_NOATIME_FL | FS_CASEFOLD_FL)
65
66struct shmem_quota_limits {
67 qsize_t usrquota_bhardlimit; /* Default user quota block hard limit */
68 qsize_t usrquota_ihardlimit; /* Default user quota inode hard limit */
69 qsize_t grpquota_bhardlimit; /* Default group quota block hard limit */
70 qsize_t grpquota_ihardlimit; /* Default group quota inode hard limit */
71};
72
73struct shmem_sb_info {
74 unsigned long max_blocks; /* How many blocks are allowed */
75 struct percpu_counter used_blocks; /* How many are allocated */
76 unsigned long max_inodes; /* How many inodes are allowed */
77 unsigned long free_ispace; /* How much ispace left for allocation */
78 raw_spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
79 umode_t mode; /* Mount mode for root directory */
80 unsigned char huge; /* Whether to try for hugepages */
81 kuid_t uid; /* Mount uid for root directory */
82 kgid_t gid; /* Mount gid for root directory */
83 bool full_inums; /* If i_ino should be uint or ino_t */
84 bool noswap; /* ignores VM reclaim / swap requests */
85 ino_t next_ino; /* The next per-sb inode number to use */
86 ino_t __percpu *ino_batch; /* The next per-cpu inode number to use */
87 struct mempolicy *mpol; /* default memory policy for mappings */
88 spinlock_t shrinklist_lock; /* Protects shrinklist */
89 struct list_head shrinklist; /* List of shinkable inodes */
90 unsigned long shrinklist_len; /* Length of shrinklist */
91 struct shmem_quota_limits qlimits; /* Default quota limits */
92};
93
94static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
95{
96 return container_of(inode, struct shmem_inode_info, vfs_inode);
97}
98
99/*
100 * Functions in mm/shmem.c called directly from elsewhere:
101 */
102extern const struct fs_parameter_spec shmem_fs_parameters[];
103extern void shmem_init(void);
104extern int shmem_init_fs_context(struct fs_context *fc);
105extern struct file *shmem_file_setup(const char *name,
106 loff_t size, unsigned long flags);
107extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
108 unsigned long flags);
109extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
110 const char *name, loff_t size, unsigned long flags);
111int shmem_zero_setup(struct vm_area_struct *vma);
112int shmem_zero_setup_desc(struct vm_area_desc *desc);
113extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
114 unsigned long len, unsigned long pgoff, unsigned long flags);
115extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
116#ifdef CONFIG_SHMEM
117bool shmem_mapping(const struct address_space *mapping);
118#else
119static inline bool shmem_mapping(const struct address_space *mapping)
120{
121 return false;
122}
123#endif /* CONFIG_SHMEM */
124void shmem_unlock_mapping(struct address_space *mapping);
125struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
126 pgoff_t index, gfp_t gfp_mask);
127int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
128 struct list_head *folio_list);
129void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end);
130int shmem_unuse(unsigned int type);
131
132#ifdef CONFIG_TRANSPARENT_HUGEPAGE
133unsigned long shmem_allowable_huge_orders(struct inode *inode,
134 struct vm_area_struct *vma, pgoff_t index,
135 loff_t write_end, bool shmem_huge_force);
136bool shmem_hpage_pmd_enabled(void);
137#else
138static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
139 struct vm_area_struct *vma, pgoff_t index,
140 loff_t write_end, bool shmem_huge_force)
141{
142 return 0;
143}
144
145static inline bool shmem_hpage_pmd_enabled(void)
146{
147 return false;
148}
149#endif
150
151#ifdef CONFIG_SHMEM
152extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
153extern void shmem_uncharge(struct inode *inode, long pages);
154#else
155static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
156{
157 return 0;
158}
159
160static inline void shmem_uncharge(struct inode *inode, long pages)
161{
162}
163#endif
164extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
165 pgoff_t start, pgoff_t end);
166
167/* Flag allocation requirements to shmem_get_folio */
168enum sgp_type {
169 SGP_READ, /* don't exceed i_size, don't allocate page */
170 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
171 SGP_CACHE, /* don't exceed i_size, may allocate page */
172 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
173 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
174};
175
176int shmem_get_folio(struct inode *inode, pgoff_t index, loff_t write_end,
177 struct folio **foliop, enum sgp_type sgp);
178struct folio *shmem_read_folio_gfp(struct address_space *mapping,
179 pgoff_t index, gfp_t gfp);
180
181static inline struct folio *shmem_read_folio(struct address_space *mapping,
182 pgoff_t index)
183{
184 return shmem_read_folio_gfp(mapping, index, gfp: mapping_gfp_mask(mapping));
185}
186
187static inline struct page *shmem_read_mapping_page(
188 struct address_space *mapping, pgoff_t index)
189{
190 return shmem_read_mapping_page_gfp(mapping, index,
191 gfp_mask: mapping_gfp_mask(mapping));
192}
193
194static inline bool shmem_file(struct file *file)
195{
196 if (!IS_ENABLED(CONFIG_SHMEM))
197 return false;
198 if (!file || !file->f_mapping)
199 return false;
200 return shmem_mapping(mapping: file->f_mapping);
201}
202
203/* Must be called with inode lock taken exclusive. */
204static inline void shmem_freeze(struct inode *inode, bool freeze)
205{
206 if (freeze)
207 SHMEM_I(inode)->flags |= SHMEM_F_MAPPING_FROZEN;
208 else
209 SHMEM_I(inode)->flags &= ~SHMEM_F_MAPPING_FROZEN;
210}
211
212/*
213 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
214 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
215 * which split_huge_page() must therefore not delete. This use of a single
216 * "fallocend" per inode errs on the side of not deleting a reservation when
217 * in doubt: there are plenty of cases when it preserves unreserved pages.
218 */
219static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
220{
221 return max(eof, SHMEM_I(inode)->fallocend);
222}
223
224extern bool shmem_charge(struct inode *inode, long pages);
225
226#ifdef CONFIG_USERFAULTFD
227#ifdef CONFIG_SHMEM
228extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
229 struct vm_area_struct *dst_vma,
230 unsigned long dst_addr,
231 unsigned long src_addr,
232 uffd_flags_t flags,
233 struct folio **foliop);
234#else /* !CONFIG_SHMEM */
235#define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
236 src_addr, flags, foliop) ({ BUG(); 0; })
237#endif /* CONFIG_SHMEM */
238#endif /* CONFIG_USERFAULTFD */
239
240/*
241 * Used space is stored as unsigned 64-bit value in bytes but
242 * quota core supports only signed 64-bit values so use that
243 * as a limit
244 */
245#define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */
246#define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL
247
248#ifdef CONFIG_TMPFS_QUOTA
249extern const struct dquot_operations shmem_quota_operations;
250extern struct quota_format_type shmem_quota_format;
251#endif /* CONFIG_TMPFS_QUOTA */
252
253#endif
254

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