Linux kernel mirror (for testing)
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linux
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);
105struct file *shmem_file_setup(const char *name, loff_t size, vma_flags_t flags);
106struct file *shmem_kernel_file_setup(const char *name, loff_t size, vma_flags_t vma_flags);
107extern struct file *shmem_file_setup_with_mnt(struct vfsmount *mnt,
108 const char *name, loff_t size, vma_flags_t flags);
109int shmem_zero_setup(struct vm_area_struct *vma);
110int shmem_zero_setup_desc(struct vm_area_desc *desc);
111extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
112 unsigned long len, unsigned long pgoff, unsigned long flags);
113extern int shmem_lock(struct file *file, int lock, struct ucounts *ucounts);
114#ifdef CONFIG_SHMEM
115bool shmem_mapping(const struct address_space *mapping);
116#else
117static inline bool shmem_mapping(const struct address_space *mapping)
118{
119 return false;
120}
121#endif /* CONFIG_SHMEM */
122void shmem_unlock_mapping(struct address_space *mapping);
123struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
124 pgoff_t index, gfp_t gfp_mask);
125int shmem_writeout(struct folio *folio, struct swap_iocb **plug,
126 struct list_head *folio_list);
127void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end);
128int shmem_unuse(unsigned int type);
129
130#ifdef CONFIG_TRANSPARENT_HUGEPAGE
131unsigned long shmem_allowable_huge_orders(struct inode *inode,
132 struct vm_area_struct *vma, pgoff_t index,
133 loff_t write_end, bool shmem_huge_force);
134bool shmem_hpage_pmd_enabled(void);
135#else
136static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
137 struct vm_area_struct *vma, pgoff_t index,
138 loff_t write_end, bool shmem_huge_force)
139{
140 return 0;
141}
142
143static inline bool shmem_hpage_pmd_enabled(void)
144{
145 return false;
146}
147#endif
148
149#ifdef CONFIG_SHMEM
150extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
151extern void shmem_uncharge(struct inode *inode, long pages);
152#else
153static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
154{
155 return 0;
156}
157
158static inline void shmem_uncharge(struct inode *inode, long pages)
159{
160}
161#endif
162extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
163 pgoff_t start, pgoff_t end);
164
165/* Flag allocation requirements to shmem_get_folio */
166enum sgp_type {
167 SGP_READ, /* don't exceed i_size, don't allocate page */
168 SGP_NOALLOC, /* similar, but fail on hole or use fallocated page */
169 SGP_CACHE, /* don't exceed i_size, may allocate page */
170 SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */
171 SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */
172};
173
174int shmem_get_folio(struct inode *inode, pgoff_t index, loff_t write_end,
175 struct folio **foliop, enum sgp_type sgp);
176struct folio *shmem_read_folio_gfp(struct address_space *mapping,
177 pgoff_t index, gfp_t gfp);
178
179static inline struct folio *shmem_read_folio(struct address_space *mapping,
180 pgoff_t index)
181{
182 return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping));
183}
184
185static inline struct page *shmem_read_mapping_page(
186 struct address_space *mapping, pgoff_t index)
187{
188 return shmem_read_mapping_page_gfp(mapping, index,
189 mapping_gfp_mask(mapping));
190}
191
192static inline bool shmem_file(struct file *file)
193{
194 if (!IS_ENABLED(CONFIG_SHMEM))
195 return false;
196 if (!file || !file->f_mapping)
197 return false;
198 return shmem_mapping(file->f_mapping);
199}
200
201/* Must be called with inode lock taken exclusive. */
202static inline void shmem_freeze(struct inode *inode, bool freeze)
203{
204 if (freeze)
205 SHMEM_I(inode)->flags |= SHMEM_F_MAPPING_FROZEN;
206 else
207 SHMEM_I(inode)->flags &= ~SHMEM_F_MAPPING_FROZEN;
208}
209
210/*
211 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
212 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
213 * which split_huge_page() must therefore not delete. This use of a single
214 * "fallocend" per inode errs on the side of not deleting a reservation when
215 * in doubt: there are plenty of cases when it preserves unreserved pages.
216 */
217static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
218{
219 return max(eof, SHMEM_I(inode)->fallocend);
220}
221
222extern bool shmem_charge(struct inode *inode, long pages);
223
224/*
225 * Used space is stored as unsigned 64-bit value in bytes but
226 * quota core supports only signed 64-bit values so use that
227 * as a limit
228 */
229#define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */
230#define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL
231
232#ifdef CONFIG_TMPFS_QUOTA
233extern const struct dquot_operations shmem_quota_operations;
234extern struct quota_format_type shmem_quota_format;
235#endif /* CONFIG_TMPFS_QUOTA */
236
237#endif