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 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 do_rmdir(int dfd, struct filename *name); 57 int do_unlinkat(int dfd, struct filename *name); 58 int may_linkat(struct mnt_idmap *idmap, const struct path *link); 59 int do_renameat2(int olddfd, struct filename *oldname, int newdfd, 60 struct filename *newname, unsigned int flags); 61 int do_mkdirat(int dfd, struct filename *name, umode_t mode); 62 int do_symlinkat(struct filename *from, int newdfd, struct filename *to); 63 int do_linkat(int olddfd, struct filename *old, int newdfd, 64 struct filename *new, int flags); 65 int vfs_tmpfile(struct mnt_idmap *idmap, 66 const struct path *parentpath, 67 struct file *file, umode_t mode); 68 struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); 69 struct dentry *start_dirop(struct dentry *parent, struct qstr *name, 70 unsigned int lookup_flags); 71 int lookup_noperm_common(struct qstr *qname, struct dentry *base); 72 73 /* 74 * namespace.c 75 */ 76 extern struct vfsmount *lookup_mnt(const struct path *); 77 extern int finish_automount(struct vfsmount *, const struct path *); 78 79 extern int sb_prepare_remount_readonly(struct super_block *); 80 81 extern void __init mnt_init(void); 82 83 int mnt_get_write_access_file(struct file *file); 84 void mnt_put_write_access_file(struct file *file); 85 86 extern void dissolve_on_fput(struct vfsmount *); 87 extern bool may_mount(void); 88 89 int path_mount(const char *dev_name, const struct path *path, 90 const char *type_page, unsigned long flags, void *data_page); 91 int path_umount(const struct path *path, int flags); 92 93 int show_path(struct seq_file *m, struct dentry *root); 94 95 /* 96 * fs_struct.c 97 */ 98 extern void chroot_fs_refs(const struct path *, const struct path *); 99 100 /* 101 * file_table.c 102 */ 103 struct file *alloc_empty_file(int flags, const struct cred *cred); 104 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred); 105 struct file *alloc_empty_backing_file(int flags, const struct cred *cred); 106 void backing_file_set_user_path(struct file *f, const struct path *path); 107 108 static inline void file_put_write_access(struct file *file) 109 { 110 put_write_access(file->f_inode); 111 mnt_put_write_access(file->f_path.mnt); 112 if (unlikely(file->f_mode & FMODE_BACKING)) 113 mnt_put_write_access(backing_file_user_path(file)->mnt); 114 } 115 116 static inline void put_file_access(struct file *file) 117 { 118 if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) { 119 i_readcount_dec(file->f_inode); 120 } else if (file->f_mode & FMODE_WRITER) { 121 file_put_write_access(file); 122 } 123 } 124 125 void fput_close_sync(struct file *); 126 void fput_close(struct file *); 127 128 /* 129 * super.c 130 */ 131 extern int reconfigure_super(struct fs_context *); 132 extern bool super_trylock_shared(struct super_block *sb); 133 struct super_block *user_get_super(dev_t, bool excl); 134 void put_super(struct super_block *sb); 135 extern bool mount_capable(struct fs_context *); 136 int sb_init_dio_done_wq(struct super_block *sb); 137 138 /* 139 * Prepare superblock for changing its read-only state (i.e., either remount 140 * read-write superblock read-only or vice versa). After this function returns 141 * mnt_is_readonly() will return true for any mount of the superblock if its 142 * caller is able to observe any changes done by the remount. This holds until 143 * sb_end_ro_state_change() is called. 144 */ 145 static inline void sb_start_ro_state_change(struct super_block *sb) 146 { 147 WRITE_ONCE(sb->s_readonly_remount, 1); 148 /* 149 * For RO->RW transition, the barrier pairs with the barrier in 150 * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY 151 * cleared, it will see s_readonly_remount set. 152 * For RW->RO transition, the barrier pairs with the barrier in 153 * mnt_get_write_access() before the mnt_is_readonly() check. 154 * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD 155 * already cleared, it will see s_readonly_remount set. 156 */ 157 smp_wmb(); 158 } 159 160 /* 161 * Ends section changing read-only state of the superblock. After this function 162 * returns if mnt_is_readonly() returns false, the caller will be able to 163 * observe all the changes remount did to the superblock. 164 */ 165 static inline void sb_end_ro_state_change(struct super_block *sb) 166 { 167 /* 168 * This barrier provides release semantics that pairs with 169 * the smp_rmb() acquire semantics in mnt_is_readonly(). 170 * This barrier pair ensure that when mnt_is_readonly() sees 171 * 0 for sb->s_readonly_remount, it will also see all the 172 * preceding flag changes that were made during the RO state 173 * change. 174 */ 175 smp_wmb(); 176 WRITE_ONCE(sb->s_readonly_remount, 0); 177 } 178 179 /* 180 * open.c 181 */ 182 struct open_flags { 183 int open_flag; 184 umode_t mode; 185 int acc_mode; 186 int intent; 187 int lookup_flags; 188 }; 189 extern struct file *do_filp_open(int dfd, struct filename *pathname, 190 const struct open_flags *op); 191 extern struct file *do_file_open_root(const struct path *, 192 const char *, const struct open_flags *); 193 extern struct open_how build_open_how(int flags, umode_t mode); 194 extern int build_open_flags(const struct open_how *how, struct open_flags *op); 195 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd); 196 197 int do_ftruncate(struct file *file, loff_t length, int small); 198 int do_sys_ftruncate(unsigned int fd, loff_t length, int small); 199 int chmod_common(const struct path *path, umode_t mode); 200 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, 201 int flag); 202 int chown_common(const struct path *path, uid_t user, gid_t group); 203 extern int vfs_open(const struct path *, struct file *); 204 205 /* 206 * inode.c 207 */ 208 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc); 209 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry); 210 bool in_group_or_capable(struct mnt_idmap *idmap, 211 const struct inode *inode, vfsgid_t vfsgid); 212 213 /* 214 * fs-writeback.c 215 */ 216 extern long get_nr_dirty_inodes(void); 217 218 /* 219 * dcache.c 220 */ 221 extern int d_set_mounted(struct dentry *dentry); 222 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); 223 extern struct dentry *d_alloc_cursor(struct dentry *); 224 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); 225 extern char *simple_dname(struct dentry *, char *, int); 226 extern void dput_to_list(struct dentry *, struct list_head *); 227 extern void shrink_dentry_list(struct list_head *); 228 extern void shrink_dcache_for_umount(struct super_block *); 229 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); 230 extern struct dentry *__d_lookup_rcu(const struct dentry *parent, 231 const struct qstr *name, unsigned *seq); 232 233 /* 234 * pipe.c 235 */ 236 extern const struct file_operations pipefifo_fops; 237 238 /* 239 * fs_pin.c 240 */ 241 extern void group_pin_kill(struct hlist_head *p); 242 extern void mnt_pin_kill(struct mount *m); 243 244 /* 245 * fs/nsfs.c 246 */ 247 extern const struct dentry_operations ns_dentry_operations; 248 int open_namespace(struct ns_common *ns); 249 struct file *open_namespace_file(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 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 } 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 */ 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