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