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
70 /*
71 * namespace.c
72 */
73 extern struct vfsmount *lookup_mnt(const struct path *);
74 extern int finish_automount(struct vfsmount *, const struct path *);
75
76 extern int sb_prepare_remount_readonly(struct super_block *);
77
78 extern void __init mnt_init(void);
79
80 int mnt_get_write_access_file(struct file *file);
81 void mnt_put_write_access_file(struct file *file);
82
83 extern void dissolve_on_fput(struct vfsmount *);
84 extern bool may_mount(void);
85
86 int path_mount(const char *dev_name, struct path *path,
87 const char *type_page, unsigned long flags, void *data_page);
88 int path_umount(struct path *path, int flags);
89
90 int show_path(struct seq_file *m, struct dentry *root);
91
92 /*
93 * fs_struct.c
94 */
95 extern void chroot_fs_refs(const struct path *, const struct path *);
96
97 /*
98 * file_table.c
99 */
100 struct file *alloc_empty_file(int flags, const struct cred *cred);
101 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
102 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
103
file_put_write_access(struct file * file)104 static inline void file_put_write_access(struct file *file)
105 {
106 put_write_access(file->f_inode);
107 mnt_put_write_access(file->f_path.mnt);
108 if (unlikely(file->f_mode & FMODE_BACKING))
109 mnt_put_write_access(backing_file_user_path(file)->mnt);
110 }
111
put_file_access(struct file * file)112 static inline void put_file_access(struct file *file)
113 {
114 if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
115 i_readcount_dec(file->f_inode);
116 } else if (file->f_mode & FMODE_WRITER) {
117 file_put_write_access(file);
118 }
119 }
120
121 void fput_close_sync(struct file *);
122 void fput_close(struct file *);
123
124 /*
125 * super.c
126 */
127 extern int reconfigure_super(struct fs_context *);
128 extern bool super_trylock_shared(struct super_block *sb);
129 struct super_block *user_get_super(dev_t, bool excl);
130 void put_super(struct super_block *sb);
131 extern bool mount_capable(struct fs_context *);
132 int sb_init_dio_done_wq(struct super_block *sb);
133
134 /*
135 * Prepare superblock for changing its read-only state (i.e., either remount
136 * read-write superblock read-only or vice versa). After this function returns
137 * mnt_is_readonly() will return true for any mount of the superblock if its
138 * caller is able to observe any changes done by the remount. This holds until
139 * sb_end_ro_state_change() is called.
140 */
sb_start_ro_state_change(struct super_block * sb)141 static inline void sb_start_ro_state_change(struct super_block *sb)
142 {
143 WRITE_ONCE(sb->s_readonly_remount, 1);
144 /*
145 * For RO->RW transition, the barrier pairs with the barrier in
146 * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
147 * cleared, it will see s_readonly_remount set.
148 * For RW->RO transition, the barrier pairs with the barrier in
149 * mnt_get_write_access() before the mnt_is_readonly() check.
150 * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
151 * already cleared, it will see s_readonly_remount set.
152 */
153 smp_wmb();
154 }
155
156 /*
157 * Ends section changing read-only state of the superblock. After this function
158 * returns if mnt_is_readonly() returns false, the caller will be able to
159 * observe all the changes remount did to the superblock.
160 */
sb_end_ro_state_change(struct super_block * sb)161 static inline void sb_end_ro_state_change(struct super_block *sb)
162 {
163 /*
164 * This barrier provides release semantics that pairs with
165 * the smp_rmb() acquire semantics in mnt_is_readonly().
166 * This barrier pair ensure that when mnt_is_readonly() sees
167 * 0 for sb->s_readonly_remount, it will also see all the
168 * preceding flag changes that were made during the RO state
169 * change.
170 */
171 smp_wmb();
172 WRITE_ONCE(sb->s_readonly_remount, 0);
173 }
174
175 /*
176 * open.c
177 */
178 struct open_flags {
179 int open_flag;
180 umode_t mode;
181 int acc_mode;
182 int intent;
183 int lookup_flags;
184 };
185 extern struct file *do_filp_open(int dfd, struct filename *pathname,
186 const struct open_flags *op);
187 extern struct file *do_file_open_root(const struct path *,
188 const char *, const struct open_flags *);
189 extern struct open_how build_open_how(int flags, umode_t mode);
190 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
191 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
192
193 int do_ftruncate(struct file *file, loff_t length, int small);
194 int do_sys_ftruncate(unsigned int fd, loff_t length, int small);
195 int chmod_common(const struct path *path, umode_t mode);
196 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
197 int flag);
198 int chown_common(const struct path *path, uid_t user, gid_t group);
199 extern int vfs_open(const struct path *, struct file *);
200
201 /*
202 * inode.c
203 */
204 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
205 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
206 bool in_group_or_capable(struct mnt_idmap *idmap,
207 const struct inode *inode, vfsgid_t vfsgid);
208
209 /*
210 * fs-writeback.c
211 */
212 extern long get_nr_dirty_inodes(void);
213
214 /*
215 * dcache.c
216 */
217 extern int d_set_mounted(struct dentry *dentry);
218 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
219 extern struct dentry *d_alloc_cursor(struct dentry *);
220 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
221 extern char *simple_dname(struct dentry *, char *, int);
222 extern void dput_to_list(struct dentry *, struct list_head *);
223 extern void shrink_dentry_list(struct list_head *);
224 extern void shrink_dcache_for_umount(struct super_block *);
225 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
226 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
227 const struct qstr *name, unsigned *seq);
228 extern void d_genocide(struct dentry *);
229
230 /*
231 * pipe.c
232 */
233 extern const struct file_operations pipefifo_fops;
234
235 /*
236 * fs_pin.c
237 */
238 extern void group_pin_kill(struct hlist_head *p);
239 extern void mnt_pin_kill(struct mount *m);
240
241 /*
242 * fs/nsfs.c
243 */
244 extern const struct dentry_operations ns_dentry_operations;
245 int open_namespace(struct ns_common *ns);
246
247 /*
248 * fs/stat.c:
249 */
250
251 int do_statx(int dfd, struct filename *filename, unsigned int flags,
252 unsigned int mask, struct statx __user *buffer);
253 int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
254 struct statx __user *buffer);
255
256 /*
257 * fs/splice.c:
258 */
259 ssize_t splice_file_to_pipe(struct file *in,
260 struct pipe_inode_info *opipe,
261 loff_t *offset,
262 size_t len, unsigned int flags);
263
264 /*
265 * fs/xattr.c:
266 */
267 struct xattr_name {
268 char name[XATTR_NAME_MAX + 1];
269 };
270
271 struct kernel_xattr_ctx {
272 /* Value of attribute */
273 union {
274 const void __user *cvalue;
275 void __user *value;
276 };
277 void *kvalue;
278 size_t size;
279 /* Attribute name */
280 struct xattr_name *kname;
281 unsigned int flags;
282 };
283
284 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
285 ssize_t filename_getxattr(int dfd, struct filename *filename,
286 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
287 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
288 int filename_setxattr(int dfd, struct filename *filename,
289 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
290 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
291 int import_xattr_name(struct xattr_name *kname, const char __user *name);
292
293 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
294
295 #ifdef CONFIG_FS_POSIX_ACL
296 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
297 const char *acl_name, const void *kvalue, size_t size);
298 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
299 const char *acl_name, void *kvalue, size_t size);
300 #else
do_set_acl(struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,const void * kvalue,size_t size)301 static inline int do_set_acl(struct mnt_idmap *idmap,
302 struct dentry *dentry, const char *acl_name,
303 const void *kvalue, size_t size)
304 {
305 return -EOPNOTSUPP;
306 }
do_get_acl(struct mnt_idmap * idmap,struct dentry * dentry,const char * acl_name,void * kvalue,size_t size)307 static inline ssize_t do_get_acl(struct mnt_idmap *idmap,
308 struct dentry *dentry, const char *acl_name,
309 void *kvalue, size_t size)
310 {
311 return -EOPNOTSUPP;
312 }
313 #endif
314
315 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
316
317 /*
318 * fs/attr.c
319 */
320 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
321 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
322 void mnt_idmap_put(struct mnt_idmap *idmap);
323 struct stashed_operations {
324 void (*put_data)(void *data);
325 int (*init_inode)(struct inode *inode, void *data);
326 };
327 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
328 struct path *path);
329 void stashed_dentry_prune(struct dentry *dentry);
330 struct dentry *stashed_dentry_get(struct dentry **stashed);
331 /**
332 * path_mounted - check whether path is mounted
333 * @path: path to check
334 *
335 * Determine whether @path refers to the root of a mount.
336 *
337 * Return: true if @path is the root of a mount, false if not.
338 */
path_mounted(const struct path * path)339 static inline bool path_mounted(const struct path *path)
340 {
341 return path->mnt->mnt_root == path->dentry;
342 }
343 void file_f_owner_release(struct file *file);
344 bool file_seek_cur_needs_f_lock(struct file *file);
345 int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map);
346