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 __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
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
100bool shmem_mapping(struct address_space *mapping);
101#else
102static inline bool shmem_mapping(struct address_space *mapping)
103{
104	return false;
105}
106#endif /* CONFIG_SHMEM */
107extern void shmem_unlock_mapping(struct address_space *mapping);
108extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
109					pgoff_t index, gfp_t gfp_mask);
110extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
111int shmem_unuse(unsigned int type);
112
113#ifdef CONFIG_TRANSPARENT_HUGEPAGE
114extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
115			  struct mm_struct *mm, unsigned long vm_flags);
116#else
117static __always_inline bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
118					  struct mm_struct *mm, unsigned long vm_flags)
119{
120	return false;
121}
122#endif
123
124#ifdef CONFIG_SHMEM
125extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
126#else
127static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
128{
129	return 0;
130}
131#endif
132extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
133						pgoff_t start, pgoff_t end);
134
135/* Flag allocation requirements to shmem_get_folio */
136enum sgp_type {
137	SGP_READ,	/* don't exceed i_size, don't allocate page */
138	SGP_NOALLOC,	/* similar, but fail on hole or use fallocated page */
139	SGP_CACHE,	/* don't exceed i_size, may allocate page */
140	SGP_WRITE,	/* may exceed i_size, may allocate !Uptodate page */
141	SGP_FALLOC,	/* like SGP_WRITE, but make existing page Uptodate */
142};
143
144int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
145		enum sgp_type sgp);
146struct folio *shmem_read_folio_gfp(struct address_space *mapping,
147		pgoff_t index, gfp_t gfp);
148
149static inline struct folio *shmem_read_folio(struct address_space *mapping,
150		pgoff_t index)
151{
152	return shmem_read_folio_gfp(mapping, index, mapping_gfp_mask(mapping));
153}
154
155static inline struct page *shmem_read_mapping_page(
156				struct address_space *mapping, pgoff_t index)
157{
158	return shmem_read_mapping_page_gfp(mapping, index,
159					mapping_gfp_mask(mapping));
160}
161
162static inline bool shmem_file(struct file *file)
163{
164	if (!IS_ENABLED(CONFIG_SHMEM))
165		return false;
166	if (!file || !file->f_mapping)
167		return false;
168	return shmem_mapping(file->f_mapping);
169}
170
171/*
172 * If fallocate(FALLOC_FL_KEEP_SIZE) has been used, there may be pages
173 * beyond i_size's notion of EOF, which fallocate has committed to reserving:
174 * which split_huge_page() must therefore not delete.  This use of a single
175 * "fallocend" per inode errs on the side of not deleting a reservation when
176 * in doubt: there are plenty of cases when it preserves unreserved pages.
177 */
178static inline pgoff_t shmem_fallocend(struct inode *inode, pgoff_t eof)
179{
180	return max(eof, SHMEM_I(inode)->fallocend);
181}
182
183extern bool shmem_charge(struct inode *inode, long pages);
184extern void shmem_uncharge(struct inode *inode, long pages);
185
186#ifdef CONFIG_USERFAULTFD
187#ifdef CONFIG_SHMEM
188extern int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
189				  struct vm_area_struct *dst_vma,
190				  unsigned long dst_addr,
191				  unsigned long src_addr,
192				  uffd_flags_t flags,
193				  struct folio **foliop);
194#else /* !CONFIG_SHMEM */
195#define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
196			       src_addr, flags, foliop) ({ BUG(); 0; })
197#endif /* CONFIG_SHMEM */
198#endif /* CONFIG_USERFAULTFD */
199
200/*
201 * Used space is stored as unsigned 64-bit value in bytes but
202 * quota core supports only signed 64-bit values so use that
203 * as a limit
204 */
205#define SHMEM_QUOTA_MAX_SPC_LIMIT 0x7fffffffffffffffLL /* 2^63-1 */
206#define SHMEM_QUOTA_MAX_INO_LIMIT 0x7fffffffffffffffLL
207
208#ifdef CONFIG_TMPFS_QUOTA
209extern const struct dquot_operations shmem_quota_operations;
210extern struct quota_format_type shmem_quota_format;
211#endif /* CONFIG_TMPFS_QUOTA */
212
213#endif
214