fs/internal.h

   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 struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *);
  70
  71 /*
  72  * namespace.c
  73  */
  74 extern struct vfsmount *lookup_mnt(const struct path *);
  75 extern int finish_automount(struct vfsmount *, const struct path *);
  76
  77 extern int sb_prepare_remount_readonly(struct super_block *);
  78
  79 extern void __init mnt_init(void);
  80
  81 int mnt_get_write_access_file(struct file *file);
  82 void mnt_put_write_access_file(struct file *file);
  83
  84 extern void dissolve_on_fput(struct vfsmount *);
  85 extern bool may_mount(void);
  86
  87 int path_mount(const char *dev_name, struct path *path,
  88                 const char *type_page, unsigned long flags, void *data_page);
  89 int path_umount(struct path *path, int flags);
  90
  91 int show_path(struct seq_file *m, struct dentry *root);
  92
  93 /*
  94  * fs_struct.c
  95  */
  96 extern void chroot_fs_refs(const struct path *, const struct path *);
  97
  98 /*
  99  * file_table.c
 100  */
 101 struct file *alloc_empty_file(int flags, const struct cred *cred);
 102 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
 103 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
 104 void backing_file_set_user_path(struct file *f, const struct path *path);
 105
 106 static inline void file_put_write_access(struct file *file)
 107 {
 108         put_write_access(file->f_inode);
 109         mnt_put_write_access(file->f_path.mnt);
 110         if (unlikely(file->f_mode & FMODE_BACKING))
 111                 mnt_put_write_access(backing_file_user_path(file)->mnt);
 112 }
 113
 114 static inline void put_file_access(struct file *file)
 115 {
 116         if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
 117                 i_readcount_dec(file->f_inode);
 118         } else if (file->f_mode & FMODE_WRITER) {
 119                 file_put_write_access(file);
 120         }
 121 }
 122
 123 void fput_close_sync(struct file *);
 124 void fput_close(struct file *);
 125
 126 /*
 127  * super.c
 128  */
 129 extern int reconfigure_super(struct fs_context *);
 130 extern bool super_trylock_shared(struct super_block *sb);
 131 struct super_block *user_get_super(dev_t, bool excl);
 132 void put_super(struct super_block *sb);
 133 extern bool mount_capable(struct fs_context *);
 134 int sb_init_dio_done_wq(struct super_block *sb);
 135
 136 /*
 137  * Prepare superblock for changing its read-only state (i.e., either remount
 138  * read-write superblock read-only or vice versa). After this function returns
 139  * mnt_is_readonly() will return true for any mount of the superblock if its
 140  * caller is able to observe any changes done by the remount. This holds until
 141  * sb_end_ro_state_change() is called.
 142  */
 143 static inline void sb_start_ro_state_change(struct super_block *sb)
 144 {
 145         WRITE_ONCE(sb->s_readonly_remount, 1);
 146         /*
 147          * For RO->RW transition, the barrier pairs with the barrier in
 148          * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
 149          * cleared, it will see s_readonly_remount set.
 150          * For RW->RO transition, the barrier pairs with the barrier in
 151          * mnt_get_write_access() before the mnt_is_readonly() check.
 152          * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
 153          * already cleared, it will see s_readonly_remount set.
 154          */
 155         smp_wmb();
 156 }
 157
 158 /*
 159  * Ends section changing read-only state of the superblock. After this function
 160  * returns if mnt_is_readonly() returns false, the caller will be able to
 161  * observe all the changes remount did to the superblock.
 162  */
 163 static inline void sb_end_ro_state_change(struct super_block *sb)
 164 {
 165         /*
 166          * This barrier provides release semantics that pairs with
 167          * the smp_rmb() acquire semantics in mnt_is_readonly().
 168          * This barrier pair ensure that when mnt_is_readonly() sees
 169          * 0 for sb->s_readonly_remount, it will also see all the
 170          * preceding flag changes that were made during the RO state
 171          * change.
 172          */
 173         smp_wmb();
 174         WRITE_ONCE(sb->s_readonly_remount, 0);
 175 }
 176
 177 /*
 178  * open.c
 179  */
 180 struct open_flags {
 181         int open_flag;
 182         umode_t mode;
 183         int acc_mode;
 184         int intent;
 185         int lookup_flags;
 186 };
 187 extern struct file *do_filp_open(int dfd, struct filename *pathname,
 188                 const struct open_flags *op);
 189 extern struct file *do_file_open_root(const struct path *,
 190                 const char *, const struct open_flags *);
 191 extern struct open_how build_open_how(int flags, umode_t mode);
 192 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
 193 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
 194
 195 int do_ftruncate(struct file *file, loff_t length, int small);
 196 int do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 197 int chmod_common(const struct path *path, umode_t mode);
 198 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
 199                 int flag);
 200 int chown_common(const struct path *path, uid_t user, gid_t group);
 201 extern int vfs_open(const struct path *, struct file *);
 202
 203 /*
 204  * inode.c
 205  */
 206 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
 207 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
 208 bool in_group_or_capable(struct mnt_idmap *idmap,
 209                          const struct inode *inode, vfsgid_t vfsgid);
 210
 211 /*
 212  * fs-writeback.c
 213  */
 214 extern long get_nr_dirty_inodes(void);
 215
 216 /*
 217  * dcache.c
 218  */
 219 extern int d_set_mounted(struct dentry *dentry);
 220 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
 221 extern struct dentry *d_alloc_cursor(struct dentry *);
 222 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
 223 extern char *simple_dname(struct dentry *, char *, int);
 224 extern void dput_to_list(struct dentry *, struct list_head *);
 225 extern void shrink_dentry_list(struct list_head *);
 226 extern void shrink_dcache_for_umount(struct super_block *);
 227 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
 228 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
 229                                 const struct qstr *name, unsigned *seq);
 230 extern void d_genocide(struct dentry *);
 231
 232 /*
 233  * pipe.c
 234  */
 235 extern const struct file_operations pipefifo_fops;
 236
 237 /*
 238  * fs_pin.c
 239  */
 240 extern void group_pin_kill(struct hlist_head *p);
 241 extern void mnt_pin_kill(struct mount *m);
 242
 243 /*
 244  * fs/nsfs.c
 245  */
 246 extern const struct dentry_operations ns_dentry_operations;
 247 int open_namespace(struct ns_common *ns);
 248
 249 /*
 250  * fs/stat.c:
 251  */
 252
 253 int do_statx(int dfd, struct filename *filename, unsigned int flags,
 254              unsigned int mask, struct statx __user *buffer);
 255 int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
 256                 struct statx __user *buffer);
 257
 258 /*
 259  * fs/splice.c:
 260  */
 261 ssize_t splice_file_to_pipe(struct file *in,
 262                             struct pipe_inode_info *opipe,
 263                             loff_t *offset,
 264                             size_t len, unsigned int flags);
 265
 266 /*
 267  * fs/xattr.c:
 268  */
 269 struct xattr_name {
 270         char name[XATTR_NAME_MAX + 1];
 271 };
 272
 273 struct kernel_xattr_ctx {
 274         /* Value of attribute */
 275         union {
 276                 const void __user *cvalue;
 277                 void __user *value;
 278         };
 279         void *kvalue;
 280         size_t size;
 281         /* Attribute name */
 282         struct xattr_name *kname;
 283         unsigned int flags;
 284 };
 285
 286 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
 287 ssize_t filename_getxattr(int dfd, struct filename *filename,
 288                           unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
 289 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
 290 int filename_setxattr(int dfd, struct filename *filename,
 291                       unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
 292 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
 293 int import_xattr_name(struct xattr_name *kname, const char __user *name);
 294
 295 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
 296
 297 #ifdef CONFIG_FS_POSIX_ACL
 298 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 299                const char *acl_name, const void *kvalue, size_t size);
 300 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 301                    const char *acl_name, void *kvalue, size_t size);
 302 #else
 303 static inline int do_set_acl(struct mnt_idmap *idmap,
 304                              struct dentry *dentry, const char *acl_name,
 305                              const void *kvalue, size_t size)
 306 {
 307         return -EOPNOTSUPP;
 308 }
 309 static inline ssize_t do_get_acl(struct mnt_idmap *idmap,
 310                                  struct dentry *dentry, const char *acl_name,
 311                                  void *kvalue, size_t size)
 312 {
 313         return -EOPNOTSUPP;
 314 }
 315 #endif
 316
 317 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
 318
 319 /*
 320  * fs/attr.c
 321  */
 322 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
 323 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
 324 void mnt_idmap_put(struct mnt_idmap *idmap);
 325 struct stashed_operations {
 326         struct dentry *(*stash_dentry)(struct dentry **stashed,
 327                                        struct dentry *dentry);
 328         void (*put_data)(void *data);
 329         int (*init_inode)(struct inode *inode, void *data);
 330 };
 331 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
 332                       struct path *path);
 333 void stashed_dentry_prune(struct dentry *dentry);
 334 struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry);
 335 struct dentry *stashed_dentry_get(struct dentry **stashed);
 336 /**
 337  * path_mounted - check whether path is mounted
 338  * @path: path to check
 339  *
 340  * Determine whether @path refers to the root of a mount.
 341  *
 342  * Return: true if @path is the root of a mount, false if not.
 343  */
 344 static inline bool path_mounted(const struct path *path)
 345 {
 346         return path->mnt->mnt_root == path->dentry;
 347 }
 348 void file_f_owner_release(struct file *file);
 349 bool file_seek_cur_needs_f_lock(struct file *file);
 350 int statmount_mnt_idmap(struct mnt_idmap *idmap, struct seq_file *seq, bool uid_map);
 351 struct dentry *find_next_child(struct dentry *parent, struct dentry *prev);
 352 int anon_inode_getattr(struct mnt_idmap *idmap, const struct path *path,
 353                        struct kstat *stat, u32 request_mask,
 354                        unsigned int query_flags);
 355 int anon_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 356                        struct iattr *attr);
 357 void pidfs_get_root(struct path *path);