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 ([email protected]) 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 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 */ 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 */ 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 long do_ftruncate(struct file *file, loff_t length, int small); 194 long 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 void invalidate_inodes(struct super_block *sb); 214 215 /* 216 * dcache.c 217 */ 218 extern int d_set_mounted(struct dentry *dentry); 219 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc); 220 extern struct dentry *d_alloc_cursor(struct dentry *); 221 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *); 222 extern char *simple_dname(struct dentry *, char *, int); 223 extern void dput_to_list(struct dentry *, struct list_head *); 224 extern void shrink_dentry_list(struct list_head *); 225 extern void shrink_dcache_for_umount(struct super_block *); 226 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); 227 extern struct dentry *__d_lookup_rcu(const struct dentry *parent, 228 const struct qstr *name, unsigned *seq); 229 extern void d_genocide(struct dentry *); 230 231 /* 232 * pipe.c 233 */ 234 extern const struct file_operations pipefifo_fops; 235 236 /* 237 * fs_pin.c 238 */ 239 extern void group_pin_kill(struct hlist_head *p); 240 extern void mnt_pin_kill(struct mount *m); 241 242 /* 243 * fs/nsfs.c 244 */ 245 extern const struct dentry_operations ns_dentry_operations; 246 int open_namespace(struct ns_common *ns); 247 248 /* 249 * fs/stat.c: 250 */ 251 252 int do_statx(int dfd, struct filename *filename, unsigned int flags, 253 unsigned int mask, struct statx __user *buffer); 254 int do_statx_fd(int fd, unsigned int flags, unsigned int mask, 255 struct statx __user *buffer); 256 257 /* 258 * fs/splice.c: 259 */ 260 ssize_t splice_file_to_pipe(struct file *in, 261 struct pipe_inode_info *opipe, 262 loff_t *offset, 263 size_t len, unsigned int flags); 264 265 /* 266 * fs/xattr.c: 267 */ 268 struct xattr_name { 269 char name[XATTR_NAME_MAX + 1]; 270 }; 271 272 struct kernel_xattr_ctx { 273 /* Value of attribute */ 274 union { 275 const void __user *cvalue; 276 void __user *value; 277 }; 278 void *kvalue; 279 size_t size; 280 /* Attribute name */ 281 struct xattr_name *kname; 282 unsigned int flags; 283 }; 284 285 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx); 286 ssize_t filename_getxattr(int dfd, struct filename *filename, 287 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx); 288 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx); 289 int filename_setxattr(int dfd, struct filename *filename, 290 unsigned int lookup_flags, struct kernel_xattr_ctx *ctx); 291 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx); 292 int import_xattr_name(struct xattr_name *kname, const char __user *name); 293 294 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode); 295 296 #ifdef CONFIG_FS_POSIX_ACL 297 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, 298 const char *acl_name, const void *kvalue, size_t size); 299 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, 300 const char *acl_name, void *kvalue, size_t size); 301 #else 302 static inline int do_set_acl(struct mnt_idmap *idmap, 303 struct dentry *dentry, const char *acl_name, 304 const void *kvalue, size_t size) 305 { 306 return -EOPNOTSUPP; 307 } 308 static inline ssize_t do_get_acl(struct mnt_idmap *idmap, 309 struct dentry *dentry, const char *acl_name, 310 void *kvalue, size_t size) 311 { 312 return -EOPNOTSUPP; 313 } 314 #endif 315 316 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos); 317 318 /* 319 * fs/attr.c 320 */ 321 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns); 322 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap); 323 void mnt_idmap_put(struct mnt_idmap *idmap); 324 struct stashed_operations { 325 void (*put_data)(void *data); 326 int (*init_inode)(struct inode *inode, void *data); 327 }; 328 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, 329 struct path *path); 330 void stashed_dentry_prune(struct dentry *dentry); 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 */ 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