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