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 filename_rmdir(int dfd, struct filename *name); 57 int filename_unlinkat(int dfd, struct filename *name); 58 int may_linkat(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(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); 112 113 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 } 120 121 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 extern bool mount_capable(struct fs_context *); 141 142 /* 143 * Prepare superblock for changing its read-only state (i.e., either remount 144 * read-write superblock read-only or vice versa). After this function returns 145 * mnt_is_readonly() will return true for any mount of the superblock if its 146 * caller is able to observe any changes done by the remount. This holds until 147 * sb_end_ro_state_change() is called. 148 */ 149 static inline void sb_start_ro_state_change(struct super_block *sb) 150 { 151 WRITE_ONCE(sb->s_readonly_remount, 1); 152 /* 153 * For RO->RW transition, the barrier pairs with the barrier in 154 * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY 155 * cleared, it will see s_readonly_remount set. 156 * For RW->RO transition, the barrier pairs with the barrier in 157 * mnt_get_write_access() before the mnt_is_readonly() check. 158 * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD 159 * already cleared, it will see s_readonly_remount set. 160 */ 161 smp_wmb(); 162 } 163 164 /* 165 * Ends section changing read-only state of the superblock. After this function 166 * returns if mnt_is_readonly() returns false, the caller will be able to 167 * observe all the changes remount did to the superblock. 168 */ 169 static inline void sb_end_ro_state_change(struct super_block *sb) 170 { 171 /* 172 * This barrier provides release semantics that pairs with 173 * the smp_rmb() acquire semantics in mnt_is_readonly(). 174 * This barrier pair ensure that when mnt_is_readonly() sees 175 * 0 for sb->s_readonly_remount, it will also see all the 176 * preceding flag changes that were made during the RO state 177 * change. 178 */ 179 smp_wmb(); 180 WRITE_ONCE(sb->s_readonly_remount, 0); 181 } 182 183 /* 184 * open.c 185 */ 186 struct open_flags { 187 int open_flag; 188 umode_t mode; 189 int acc_mode; 190 int intent; 191 int lookup_flags; 192 }; 193 extern struct file *do_file_open(int dfd, struct filename *pathname, 194 const struct open_flags *op); 195 extern struct file *do_file_open_root(const struct path *, 196 const char *, const struct open_flags *); 197 extern struct open_how build_open_how(int flags, umode_t mode); 198 extern int build_open_flags(const struct open_how *how, struct open_flags *op); 199 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd); 200 201 int do_ftruncate(struct file *file, loff_t length, unsigned int flags); 202 int chmod_common(const struct path *path, umode_t mode); 203 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group, 204 int flag); 205 int chown_common(const struct path *path, uid_t user, gid_t group); 206 extern int vfs_open(const struct path *, struct file *); 207 208 /* 209 * inode.c 210 */ 211 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc); 212 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry); 213 bool in_group_or_capable(struct mnt_idmap *idmap, 214 const struct inode *inode, vfsgid_t vfsgid); 215 216 /* 217 * fs-writeback.c 218 */ 219 long get_nr_dirty_inodes(void); 220 bool sync_lazytime(struct inode *inode); 221 222 /* 223 * dcache.c 224 */ 225 extern int d_set_mounted(struct dentry *dentry); 226 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); 227 extern struct dentry *d_alloc_cursor(struct dentry *); 228 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); 229 extern char *simple_dname(struct dentry *, char *, int); 230 extern void dput_to_list(struct dentry *, struct list_head *); 231 extern void shrink_dentry_list(struct list_head *); 232 extern void shrink_dcache_for_umount(struct super_block *); 233 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); 234 extern struct dentry *__d_lookup_rcu(const struct dentry *parent, 235 const struct qstr *name, unsigned *seq); 236 237 /* 238 * pipe.c 239 */ 240 extern const struct file_operations pipefifo_fops; 241 242 /* 243 * fs_pin.c 244 */ 245 extern void group_pin_kill(struct hlist_head *p); 246 extern void mnt_pin_kill(struct mount *m); 247 248 /* 249 * fs/nsfs.c 250 */ 251 extern const struct dentry_operations ns_dentry_operations; 252 int open_namespace(struct ns_common *ns); 253 struct file *open_namespace_file(struct ns_common *ns); 254 255 /* 256 * fs/stat.c: 257 */ 258 259 int do_statx(int dfd, struct filename *filename, unsigned int flags, 260 unsigned int mask, struct statx __user *buffer); 261 int do_statx_fd(int fd, unsigned int flags, unsigned int mask, 262 struct statx __user *buffer); 263 264 /* 265 * fs/splice.c: 266 */ 267 ssize_t splice_file_to_pipe(struct file *in, 268 struct pipe_inode_info *opipe, 269 loff_t *offset, 270 size_t len, unsigned int flags); 271 272 /* 273 * fs/xattr.c: 274 */ 275 struct xattr_name { 276 char name[XATTR_NAME_MAX + 1]; 277 }; 278 279 struct kernel_xattr_ctx { 280 /* Value of attribute */ 281 union { 282 const void __user *cvalue; 283 void __user *value; 284 }; 285 void *kvalue; 286 size_t size; 287 /* Attribute name */ 288 struct xattr_name *kname; 289 unsigned int flags; 290 }; 291 292 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx); 293 ssize_t filename_getxattr(int dfd, struct filename *filename, 294 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx); 295 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx); 296 int filename_setxattr(int dfd, struct filename *filename, 297 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx); 298 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx); 299 int import_xattr_name(struct xattr_name *kname, const char __user *name); 300 301 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode); 302 303 #ifdef CONFIG_FS_POSIX_ACL 304 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 305 const char *acl_name, const void *kvalue, size_t size); 306 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, 307 const char *acl_name, void *kvalue, size_t size); 308 #else 309 static inline int do_set_acl(struct mnt_idmap *idmap, 310 struct dentry *dentry, const char *acl_name, 311 const void *kvalue, size_t size) 312 { 313 return -EOPNOTSUPP; 314 } 315 static inline ssize_t do_get_acl(struct mnt_idmap *idmap, 316 struct dentry *dentry, const char *acl_name, 317 void *kvalue, size_t size) 318 { 319 return -EOPNOTSUPP; 320 } 321 #endif 322 323 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos); 324 325 /* 326 * fs/attr.c 327 */ 328 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns); 329 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap); 330 void mnt_idmap_put(struct mnt_idmap *idmap); 331 struct stashed_operations { 332 struct dentry *(*stash_dentry)(struct dentry **stashed, 333 struct dentry *dentry); 334 void (*put_data)(void *data); 335 int (*init_inode)(struct inode *inode, void *data); 336 }; 337 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, 338 struct path *path); 339 void stashed_dentry_prune(struct dentry *dentry); 340 struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry); 341 struct dentry *stashed_dentry_get(struct dentry **stashed); 342 /** 343 * path_mounted - check whether path is mounted 344 * @path: path to check 345 * 346 * Determine whether @path refers to the root of a mount. 347 * 348 * Return: true if @path is the root of a mount, false if not. 349 */ 350 static inline bool path_mounted(const struct path *path) 351 { 352 return path->mnt->mnt_root == path->dentry; 353 } 354 void file_f_owner_release(struct file *file); 355 bool file_seek_cur_needs_f_lock(struct file *file); 356 int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map); 357 struct dentry *find_next_child(struct dentry *parent, struct dentry *prev); 358 int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path, 359 struct kstat *stat, u32 request_mask, 360 unsigned int query_flags); 361 int anon_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, 362 struct iattr *attr); 363 void pidfs_get_root(struct path *path); 364 void nsfs_get_root(struct path *path); 365