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