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 int parse_monolithic_mount_data(struct fs_context *, void *);
48 extern void vfs_clean_context(struct fs_context *fc);
49 extern int finish_clean_context(struct fs_context *fc);
50
51 /*
52 * namei.c
53 */
54 extern int filename_lookup(int dfd, struct filename *name, unsigned flags,
55 struct path *path, const struct path *root);
56 int filename_rmdir(int dfd, struct filename *name);
57 int filename_unlinkat(int dfd, struct filename *name);
58 int may_linkat(const struct mnt_idmap *idmap, const struct path *link);
59 int filename_renameat2(int olddfd, struct filename *oldname, int newdfd,
60 struct filename *newname, unsigned int flags);
61 int filename_mkdirat(int dfd, struct filename *name, umode_t mode);
62 int filename_mknodat(int dfd, struct filename *name, umode_t mode, unsigned int dev);
63 int filename_symlinkat(struct filename *from, int newdfd, struct filename *to);
64 int filename_linkat(int olddfd, struct filename *old, int newdfd,
65 struct filename *new, int flags);
66 int vfs_tmpfile(const 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 struct dentry *start_dirop(struct dentry *parent, struct qstr *name,
71 unsigned int lookup_flags);
72 int lookup_noperm_common(struct qstr *qname, struct dentry *base);
73
74 void __init filename_init(void);
75
76 /*
77 * namespace.c
78 */
79 extern struct vfsmount *lookup_mnt(const struct path *);
80 extern int finish_automount(struct vfsmount *, const struct path *);
81
82 extern int sb_prepare_remount_readonly(struct super_block *);
83
84 extern void __init mnt_init(void);
85
86 int mnt_get_write_access_file(struct file *file);
87 void mnt_put_write_access_file(struct file *file);
88
89 extern void dissolve_on_fput(struct vfsmount *);
90 extern bool may_mount(void);
91
92 int path_mount(const char *dev_name, const struct path *path,
93 const char *type_page, unsigned long flags, void *data_page);
94 int path_umount(const struct path *path, int flags);
95 int path_pivot_root(struct path *new, struct path *old);
96
97 int show_path(struct seq_file *m, struct dentry *root);
98
99 /*
100 * fs_struct.c
101 */
102 extern void chroot_fs_refs(const struct path *, const struct path *);
103
104 /*
105 * file_table.c
106 */
107 struct file *alloc_empty_file(int flags, const struct cred *cred);
108 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
109 struct file *alloc_empty_backing_file(int flags, const struct cred *cred,
110 const struct file *user_file);
111 void backing_file_set_user_path(struct file *f, const struct path *path);
112
file_put_write_access(struct file * file)113 static inline void file_put_write_access(struct file *file)
114 {
115 put_write_access(file->f_inode);
116 mnt_put_write_access(file->f_path.mnt);
117 if (unlikely(file->f_mode & FMODE_BACKING))
118 mnt_put_write_access(backing_file_user_path(file)->mnt);
119 }
120
put_file_access(struct file * file)121 static inline void put_file_access(struct file *file)
122 {
123 if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
124 i_readcount_dec(file->f_inode);
125 } else if (file->f_mode & FMODE_WRITER) {
126 file_put_write_access(file);
127 }
128 }
129
130 void fput_close_sync(struct file *);
131 void fput_close(struct file *);
132
133 /*
134 * super.c
135 */
136 extern int reconfigure_super(struct fs_context *);
137 extern bool super_trylock_shared(struct super_block *sb);
138 struct super_block *user_get_super(dev_t, bool excl);
139 void put_super(struct super_block *sb);
140 void __init super_dev_init(void);
141 extern bool mount_capable(struct fs_context *);
142
143 /*
144 * Prepare superblock for changing its read-only state (i.e., either remount
145 * read-write superblock read-only or vice versa). After this function returns
146 * mnt_is_readonly() will return true for any mount of the superblock if its
147 * caller is able to observe any changes done by the remount. This holds until
148 * sb_end_ro_state_change() is called.
149 */
sb_start_ro_state_change(struct super_block * sb)150 static inline void sb_start_ro_state_change(struct super_block *sb)
151 {
152 WRITE_ONCE(sb->s_readonly_remount, 1);
153 /*
154 * For RO->RW transition, the barrier pairs with the barrier in
155 * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
156 * cleared, it will see s_readonly_remount set.
157 * For RW->RO transition, the barrier pairs with the barrier in
158 * mnt_get_write_access() before the mnt_is_readonly() check.
159 * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
160 * already cleared, it will see s_readonly_remount set.
161 */
162 smp_wmb();
163 }
164
165 /*
166 * Ends section changing read-only state of the superblock. After this function
167 * returns if mnt_is_readonly() returns false, the caller will be able to
168 * observe all the changes remount did to the superblock.
169 */
sb_end_ro_state_change(struct super_block * sb)170 static inline void sb_end_ro_state_change(struct super_block *sb)
171 {
172 /*
173 * This barrier provides release semantics that pairs with
174 * the smp_rmb() acquire semantics in mnt_is_readonly().
175 * This barrier pair ensure that when mnt_is_readonly() sees
176 * 0 for sb->s_readonly_remount, it will also see all the
177 * preceding flag changes that were made during the RO state
178 * change.
179 */
180 smp_wmb();
181 WRITE_ONCE(sb->s_readonly_remount, 0);
182 }
183
184 /*
185 * open.c
186 */
187 struct open_flags {
188 int open_flag;
189 umode_t mode;
190 int acc_mode;
191 int intent;
192 int lookup_flags;
193 };
194 extern struct file *do_file_open(int dfd, struct filename *pathname,
195 const struct open_flags *op);
196 extern struct file *do_file_open_root(const struct path *,
197 const char *, const struct open_flags *);
198 extern struct open_how build_open_how(int flags, umode_t mode);
199 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
200 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
201 int filp_close_sync(struct file *filp, fl_owner_t id);
202
203 int do_ftruncate(struct file *file, loff_t length, unsigned int flags);
204 int chmod_common(const struct path *path, umode_t mode);
205 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
206 int flag);
207 int chown_common(const struct path *path, uid_t user, gid_t group);
208 extern int vfs_open(const struct path *, struct file *);
209 int vfs_open_consume(struct path *, struct file *);
210
211 /*
212 * inode.c
213 */
214 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
215 int dentry_needs_remove_privs(const struct mnt_idmap *, struct dentry *dentry);
216 bool in_group_or_capable(const struct mnt_idmap *idmap,
217 const struct inode *inode, vfsgid_t vfsgid);
218
219 /*
220 * fs-writeback.c
221 */
222 long get_nr_dirty_inodes(void);
223 bool sync_lazytime(struct inode *inode);
224
225 /*
226 * dcache.c
227 */
228 extern int d_set_mounted(struct dentry *dentry);
229 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
230 extern struct dentry *d_alloc_cursor(struct dentry *);
231 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
232 extern char *simple_dname(struct dentry *, char *, int);
233 extern void dput_to_list(struct dentry *, struct list_head *);
234 extern void shrink_dentry_list(struct list_head *);
235 extern void shrink_dcache_for_umount(struct super_block *);
236 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
237 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
238 const struct qstr *name, unsigned *seq);
239
240 /*
241 * pipe.c
242 */
243 extern const struct file_operations pipefifo_fops;
244
245 /*
246 * fs_pin.c
247 */
248 extern void group_pin_kill(struct hlist_head *p);
249 extern void mnt_pin_kill(struct mount *m);
250
251 /*
252 * fs/nsfs.c
253 */
254 extern const struct dentry_operations ns_dentry_operations;
255 int open_namespace(struct ns_common *ns);
256 struct file *open_namespace_file(struct ns_common *ns);
257
258 /*
259 * fs/stat.c:
260 */
261
262 int do_statx(int dfd, struct filename *filename, unsigned int flags,
263 unsigned int mask, struct statx __user *buffer);
264 int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
265 struct statx __user *buffer);
266
267 /*
268 * fs/splice.c:
269 */
270 ssize_t splice_file_to_pipe(struct file *in,
271 struct pipe_inode_info *opipe,
272 loff_t *offset,
273 size_t len, unsigned int flags);
274
275 /*
276 * fs/xattr.c:
277 */
278 struct xattr_name {
279 char name[XATTR_NAME_MAX + 1];
280 };
281
282 struct kernel_xattr_ctx {
283 /* Value of attribute */
284 union {
285 const void __user *cvalue;
286 void __user *value;
287 };
288 void *kvalue;
289 size_t size;
290 /* Attribute name */
291 struct xattr_name *kname;
292 unsigned int flags;
293 };
294
295 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
296 ssize_t filename_getxattr(int dfd, struct filename *filename,
297 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
298 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
299 int filename_setxattr(int dfd, struct filename *filename,
300 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
301 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
302 int import_xattr_name(struct xattr_name *kname, const char __user *name);
303
304 int may_write_xattr(const struct mnt_idmap *idmap, struct inode *inode);
305
306 #ifdef CONFIG_FS_POSIX_ACL
307 int do_set_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
308 const char *acl_name, const void *kvalue, size_t size);
309 ssize_t do_get_acl(const struct mnt_idmap *idmap, struct dentry *dentry,
310 const char *acl_name, void *kvalue, size_t size);
311 #else
do_set_acl(const struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,const void * kvalue,size_t size)312 static inline int do_set_acl(const struct mnt_idmap *idmap,
313 struct dentry *dentry, const char *acl_name,
314 const void *kvalue, size_t size)
315 {
316 return -EOPNOTSUPP;
317 }
do_get_acl(const struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,void * kvalue,size_t size)318 static inline ssize_t do_get_acl(const struct mnt_idmap *idmap,
319 struct dentry *dentry, const char *acl_name,
320 void *kvalue, size_t size)
321 {
322 return -EOPNOTSUPP;
323 }
324 #endif
325
326 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
327
328 /*
329 * fs/attr.c
330 */
331 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
332 const struct mnt_idmap *mnt_idmap_get(const struct mnt_idmap *idmap);
333 void mnt_idmap_put(const struct mnt_idmap *idmap);
334 struct stashed_operations {
335 struct dentry *(*stash_dentry)(struct dentry **stashed,
336 struct dentry *dentry);
337 void (*put_data)(void *data);
338 int (*init_inode)(struct inode *inode, void *data);
339 };
340 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
341 struct path *path);
342 void stashed_dentry_prune(struct dentry *dentry);
343 struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry);
344 struct dentry *stashed_dentry_get(struct dentry **stashed);
345 /**
346 * path_mounted - check whether path is mounted
347 * @path: path to check
348 *
349 * Determine whether @path refers to the root of a mount.
350 *
351 * Return: true if @path is the root of a mount, false if not.
352 */
path_mounted(const struct path * path)353 static inline bool path_mounted(const struct path *path)
354 {
355 return path->mnt->mnt_root == path->dentry;
356 }
357 void file_f_owner_release(struct file *file);
358 bool file_seek_cur_needs_f_lock(struct file *file);
359 int statmount_mnt_idmap(const struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map);
360 struct dentry *find_next_child(struct dentry *parent, struct dentry *prev);
361 int anon_inode_getattr(const struct mnt_idmap *idmap, const struct path *path,
362 struct kstat *stat, u32 request_mask,
363 unsigned int query_flags);
364 int anon_inode_setattr(const struct mnt_idmap *idmap, struct dentry *dentry,
365 struct iattr *attr);
366 void pidfs_get_root(struct path *path);
367 void nsfs_get_root(struct path *path);
368 void failfs_get_root(struct path *path);
369 void __init failfs_init(void);
370 bool failfs_mnt(const struct vfsmount *mnt);
371 int failfs_current_chdir(void);
372