1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* fs/ internal definitions
3 *
4 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 struct super_block;
9 struct file_system_type;
10 struct iomap;
11 struct iomap_ops;
12 struct linux_binprm;
13 struct path;
14 struct mount;
15 struct shrink_control;
16 struct fs_context;
17 struct pipe_inode_info;
18 struct iov_iter;
19 struct mnt_idmap;
20 struct ns_common;
21
22 /*
23 * block/bdev.c
24 */
25 #ifdef CONFIG_BLOCK
26 extern void __init bdev_cache_init(void);
27 #else
bdev_cache_init(void)28 static inline void bdev_cache_init(void)
29 {
30 }
31 #endif /* CONFIG_BLOCK */
32
33 /*
34 * buffer.c
35 */
36 int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
37 get_block_t *get_block, const struct iomap *iomap);
38
39 /*
40 * char_dev.c
41 */
42 extern void __init chrdev_init(void);
43
44 /*
45 * fs_context.c
46 */
47 extern const struct fs_context_operations legacy_fs_context_ops;
48 extern int parse_monolithic_mount_data(struct fs_context *, void *);
49 extern void vfs_clean_context(struct fs_context *fc);
50 extern int finish_clean_context(struct fs_context *fc);
51
52 /*
53 * namei.c
54 */
55 extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
56 struct path *path, struct path *root);
57 int do_rmdir(int dfd, struct filename *name);
58 int do_unlinkat(int dfd, struct filename *name);
59 int may_linkat(struct mnt_idmap *idmap, const struct path *link);
60 int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
61 struct filename *newname, unsigned int flags);
62 int do_mkdirat(int dfd, struct filename *name, umode_t mode);
63 int do_symlinkat(struct filename *from, int newdfd, struct filename *to);
64 int do_linkat(int olddfd, struct filename *old, int newdfd,
65 struct filename *new, int flags);
66 int vfs_tmpfile(struct mnt_idmap *idmap,
67 const struct path *parentpath,
68 struct file *file, umode_t mode);
69 struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
70
71 /*
72 * namespace.c
73 */
74 extern struct vfsmount *lookup_mnt(const struct path *);
75 extern int finish_automount(struct vfsmount *, const struct path *);
76
77 extern int sb_prepare_remount_readonly(struct super_block *);
78
79 extern void __init mnt_init(void);
80
81 int mnt_get_write_access_file(struct file *file);
82 void mnt_put_write_access_file(struct file *file);
83
84 extern void dissolve_on_fput(struct vfsmount *);
85 extern bool may_mount(void);
86
87 int path_mount(const char *dev_name, struct path *path,
88 const char *type_page, unsigned long flags, void *data_page);
89 int path_umount(struct path *path, int flags);
90
91 int show_path(struct seq_file *m, struct dentry *root);
92
93 /*
94 * fs_struct.c
95 */
96 extern void chroot_fs_refs(const struct path *, const struct path *);
97
98 /*
99 * file_table.c
100 */
101 struct file *alloc_empty_file(int flags, const struct cred *cred);
102 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
103 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
104 void backing_file_set_user_path(struct file *f, const struct path *path);
105
file_put_write_access(struct file * file)106 static inline void file_put_write_access(struct file *file)
107 {
108 put_write_access(file->f_inode);
109 mnt_put_write_access(file->f_path.mnt);
110 if (unlikely(file->f_mode & FMODE_BACKING))
111 mnt_put_write_access(backing_file_user_path(file)->mnt);
112 }
113
put_file_access(struct file * file)114 static inline void put_file_access(struct file *file)
115 {
116 if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
117 i_readcount_dec(file->f_inode);
118 } else if (file->f_mode & FMODE_WRITER) {
119 file_put_write_access(file);
120 }
121 }
122
123 void fput_close_sync(struct file *);
124 void fput_close(struct file *);
125
126 /*
127 * super.c
128 */
129 extern int reconfigure_super(struct fs_context *);
130 extern bool super_trylock_shared(struct super_block *sb);
131 struct super_block *user_get_super(dev_t, bool excl);
132 void put_super(struct super_block *sb);
133 extern bool mount_capable(struct fs_context *);
134 int sb_init_dio_done_wq(struct super_block *sb);
135
136 /*
137 * Prepare superblock for changing its read-only state (i.e., either remount
138 * read-write superblock read-only or vice versa). After this function returns
139 * mnt_is_readonly() will return true for any mount of the superblock if its
140 * caller is able to observe any changes done by the remount. This holds until
141 * sb_end_ro_state_change() is called.
142 */
sb_start_ro_state_change(struct super_block * sb)143 static inline void sb_start_ro_state_change(struct super_block *sb)
144 {
145 WRITE_ONCE(sb->s_readonly_remount, 1);
146 /*
147 * For RO->RW transition, the barrier pairs with the barrier in
148 * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
149 * cleared, it will see s_readonly_remount set.
150 * For RW->RO transition, the barrier pairs with the barrier in
151 * mnt_get_write_access() before the mnt_is_readonly() check.
152 * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
153 * already cleared, it will see s_readonly_remount set.
154 */
155 smp_wmb();
156 }
157
158 /*
159 * Ends section changing read-only state of the superblock. After this function
160 * returns if mnt_is_readonly() returns false, the caller will be able to
161 * observe all the changes remount did to the superblock.
162 */
sb_end_ro_state_change(struct super_block * sb)163 static inline void sb_end_ro_state_change(struct super_block *sb)
164 {
165 /*
166 * This barrier provides release semantics that pairs with
167 * the smp_rmb() acquire semantics in mnt_is_readonly().
168 * This barrier pair ensure that when mnt_is_readonly() sees
169 * 0 for sb->s_readonly_remount, it will also see all the
170 * preceding flag changes that were made during the RO state
171 * change.
172 */
173 smp_wmb();
174 WRITE_ONCE(sb->s_readonly_remount, 0);
175 }
176
177 /*
178 * open.c
179 */
180 struct open_flags {
181 int open_flag;
182 umode_t mode;
183 int acc_mode;
184 int intent;
185 int lookup_flags;
186 };
187 extern struct file *do_filp_open(int dfd, struct filename *pathname,
188 const struct open_flags *op);
189 extern struct file *do_file_open_root(const struct path *,
190 const char *, const struct open_flags *);
191 extern struct open_how build_open_how(int flags, umode_t mode);
192 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
193 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
194
195 int do_ftruncate(struct file *file, loff_t length, int small);
196 int do_sys_ftruncate(unsigned int fd, loff_t length, int small);
197 int chmod_common(const struct path *path, umode_t mode);
198 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
199 int flag);
200 int chown_common(const struct path *path, uid_t user, gid_t group);
201 extern int vfs_open(const struct path *, struct file *);
202
203 /*
204 * inode.c
205 */
206 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
207 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
208 bool in_group_or_capable(struct mnt_idmap *idmap,
209 const struct inode *inode, vfsgid_t vfsgid);
210
211 /*
212 * fs-writeback.c
213 */
214 extern long get_nr_dirty_inodes(void);
215
216 /*
217 * dcache.c
218 */
219 extern int d_set_mounted(struct dentry *dentry);
220 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
221 extern struct dentry *d_alloc_cursor(struct dentry *);
222 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
223 extern char *simple_dname(struct dentry *, char *, int);
224 extern void dput_to_list(struct dentry *, struct list_head *);
225 extern void shrink_dentry_list(struct list_head *);
226 extern void shrink_dcache_for_umount(struct super_block *);
227 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
228 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
229 const struct qstr *name, unsigned *seq);
230 extern void d_genocide(struct dentry *);
231
232 /*
233 * pipe.c
234 */
235 extern const struct file_operations pipefifo_fops;
236
237 /*
238 * fs_pin.c
239 */
240 extern void group_pin_kill(struct hlist_head *p);
241 extern void mnt_pin_kill(struct mount *m);
242
243 /*
244 * fs/nsfs.c
245 */
246 extern const struct dentry_operations ns_dentry_operations;
247 int open_namespace(struct ns_common *ns);
248
249 /*
250 * fs/stat.c:
251 */
252
253 int do_statx(int dfd, struct filename *filename, unsigned int flags,
254 unsigned int mask, struct statx __user *buffer);
255 int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
256 struct statx __user *buffer);
257
258 /*
259 * fs/splice.c:
260 */
261 ssize_t splice_file_to_pipe(struct file *in,
262 struct pipe_inode_info *opipe,
263 loff_t *offset,
264 size_t len, unsigned int flags);
265
266 /*
267 * fs/xattr.c:
268 */
269 struct xattr_name {
270 char name[XATTR_NAME_MAX + 1];
271 };
272
273 struct kernel_xattr_ctx {
274 /* Value of attribute */
275 union {
276 const void __user *cvalue;
277 void __user *value;
278 };
279 void *kvalue;
280 size_t size;
281 /* Attribute name */
282 struct xattr_name *kname;
283 unsigned int flags;
284 };
285
286 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
287 ssize_t filename_getxattr(int dfd, struct filename *filename,
288 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
289 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
290 int filename_setxattr(int dfd, struct filename *filename,
291 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
292 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
293 int import_xattr_name(struct xattr_name *kname, const char __user *name);
294
295 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
296
297 #ifdef CONFIG_FS_POSIX_ACL
298 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
299 const char *acl_name, const void *kvalue, size_t size);
300 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
301 const char *acl_name, void *kvalue, size_t size);
302 #else
do_set_acl(struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,const void * kvalue,size_t size)303 static inline int do_set_acl(struct mnt_idmap *idmap,
304 struct dentry *dentry, const char *acl_name,
305 const void *kvalue, size_t size)
306 {
307 return -EOPNOTSUPP;
308 }
do_get_acl(struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,void * kvalue,size_t size)309 static inline ssize_t do_get_acl(struct mnt_idmap *idmap,
310 struct dentry *dentry, const char *acl_name,
311 void *kvalue, size_t size)
312 {
313 return -EOPNOTSUPP;
314 }
315 #endif
316
317 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
318
319 /*
320 * fs/attr.c
321 */
322 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
323 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
324 void mnt_idmap_put(struct mnt_idmap *idmap);
325 struct stashed_operations {
326 struct dentry *(*stash_dentry)(struct dentry **stashed,
327 struct dentry *dentry);
328 void (*put_data)(void *data);
329 int (*init_inode)(struct inode *inode, void *data);
330 };
331 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
332 struct path *path);
333 void stashed_dentry_prune(struct dentry *dentry);
334 struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry);
335 struct dentry *stashed_dentry_get(struct dentry **stashed);
336 /**
337 * path_mounted - check whether path is mounted
338 * @path: path to check
339 *
340 * Determine whether @path refers to the root of a mount.
341 *
342 * Return: true if @path is the root of a mount, false if not.
343 */
path_mounted(const struct path * path)344 static inline bool path_mounted(const struct path *path)
345 {
346 return path->mnt->mnt_root == path->dentry;
347 }
348 void file_f_owner_release(struct file *file);
349 bool file_seek_cur_needs_f_lock(struct file *file);
350 int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map);
351 struct dentry *find_next_child(struct dentry *parent, struct dentry *prev);
352 int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path,
353 struct kstat *stat, u32 request_mask,
354 unsigned int query_flags);
355 int anon_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
356 struct iattr *attr);
357 void pidfs_get_root(struct path *path);
358