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
  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 do_statx(int dfd, struct filename *filename, unsigned int flags,
 250              unsigned int mask, struct statx __user *buffer);
 251 int do_statx_fd(int fd, unsigned int flags, unsigned int mask,
 252                 struct statx __user *buffer);
 253
 254 /*
 255  * fs/splice.c:
 256  */
 257 ssize_t splice_file_to_pipe(struct file *in,
 258                             struct pipe_inode_info *opipe,
 259                             loff_t *offset,
 260                             size_t len, unsigned int flags);
 261
 262 /*
 263  * fs/xattr.c:
 264  */
 265 struct xattr_name {
 266         char name[XATTR_NAME_MAX + 1];
 267 };
 268
 269 struct kernel_xattr_ctx {
 270         /* Value of attribute */
 271         union {
 272                 const void __user *cvalue;
 273                 void __user *value;
 274         };
 275         void *kvalue;
 276         size_t size;
 277         /* Attribute name */
 278         struct xattr_name *kname;
 279         unsigned int flags;
 280 };
 281
 282 ssize_t file_getxattr(struct file *file, struct kernel_xattr_ctx *ctx);
 283 ssize_t filename_getxattr(int dfd, struct filename *filename,
 284                           unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
 285 int file_setxattr(struct file *file, struct kernel_xattr_ctx *ctx);
 286 int filename_setxattr(int dfd, struct filename *filename,
 287                       unsigned int lookup_flags, struct kernel_xattr_ctx *ctx);
 288 int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx);
 289 int import_xattr_name(struct xattr_name *kname, const char __user *name);
 290
 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 void file_f_owner_release(struct file *file);