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
  21 /*
  22  * block/bdev.c
  23  */
  24 #ifdef CONFIG_BLOCK
  25 extern void __init bdev_cache_init(void);
  26 #else
  27 static inline void bdev_cache_init(void)
  28 {
  29 }
  30 #endif /* CONFIG_BLOCK */
  31
  32 /*
  33  * buffer.c
  34  */
  35 int __block_write_begin_int(struct folio *folio, loff_t pos, unsigned len,
  36                 get_block_t *get_block, const struct iomap *iomap);
  37
  38 /*
  39  * char_dev.c
  40  */
  41 extern void __init chrdev_init(void);
  42
  43 /*
  44  * fs_context.c
  45  */
  46 extern const struct fs_context_operations legacy_fs_context_ops;
  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, struct path *root);
  56 int do_rmdir(int dfd, struct filename *name);
  57 int do_unlinkat(int dfd, struct filename *name);
  58 int may_linkat(struct mnt_idmap *idmap, const struct path *link);
  59 int do_renameat2(int olddfd, struct filename *oldname, int newdfd,
  60                  struct filename *newname, unsigned int flags);
  61 int do_mkdirat(int dfd, struct filename *name, umode_t mode);
  62 int do_symlinkat(struct filename *from, int newdfd, struct filename *to);
  63 int do_linkat(int olddfd, struct filename *old, int newdfd,
  64                         struct filename *new, int flags);
  65
  66 /*
  67  * namespace.c
  68  */
  69 extern struct vfsmount *lookup_mnt(const struct path *);
  70 extern int finish_automount(struct vfsmount *, const struct path *);
  71
  72 extern int sb_prepare_remount_readonly(struct super_block *);
  73
  74 extern void __init mnt_init(void);
  75
  76 int mnt_get_write_access_file(struct file *file);
  77 void mnt_put_write_access_file(struct file *file);
  78
  79 extern void dissolve_on_fput(struct vfsmount *);
  80 extern bool may_mount(void);
  81
  82 int path_mount(const char *dev_name, struct path *path,
  83                 const char *type_page, unsigned long flags, void *data_page);
  84 int path_umount(struct path *path, int flags);
  85
  86 /*
  87  * fs_struct.c
  88  */
  89 extern void chroot_fs_refs(const struct path *, const struct path *);
  90
  91 /*
  92  * file_table.c
  93  */
  94 struct file *alloc_empty_file(int flags, const struct cred *cred);
  95 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
  96 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
  97 void release_empty_file(struct file *f);
  98
  99 static inline void file_put_write_access(struct file *file)
 100 {
 101         put_write_access(file->f_inode);
 102         mnt_put_write_access(file->f_path.mnt);
 103         if (unlikely(file->f_mode & FMODE_BACKING))
 104                 mnt_put_write_access(backing_file_user_path(file)->mnt);
 105 }
 106
 107 static inline void put_file_access(struct file *file)
 108 {
 109         if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
 110                 i_readcount_dec(file->f_inode);
 111         } else if (file->f_mode & FMODE_WRITER) {
 112                 file_put_write_access(file);
 113         }
 114 }
 115
 116 /*
 117  * super.c
 118  */
 119 extern int reconfigure_super(struct fs_context *);
 120 extern bool super_trylock_shared(struct super_block *sb);
 121 struct super_block *user_get_super(dev_t, bool excl);
 122 void put_super(struct super_block *sb);
 123 extern bool mount_capable(struct fs_context *);
 124 int sb_init_dio_done_wq(struct super_block *sb);
 125
 126 /*
 127  * Prepare superblock for changing its read-only state (i.e., either remount
 128  * read-write superblock read-only or vice versa). After this function returns
 129  * mnt_is_readonly() will return true for any mount of the superblock if its
 130  * caller is able to observe any changes done by the remount. This holds until
 131  * sb_end_ro_state_change() is called.
 132  */
 133 static inline void sb_start_ro_state_change(struct super_block *sb)
 134 {
 135         WRITE_ONCE(sb->s_readonly_remount, 1);
 136         /*
 137          * For RO->RW transition, the barrier pairs with the barrier in
 138          * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
 139          * cleared, it will see s_readonly_remount set.
 140          * For RW->RO transition, the barrier pairs with the barrier in
 141          * mnt_get_write_access() before the mnt_is_readonly() check.
 142          * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
 143          * already cleared, it will see s_readonly_remount set.
 144          */
 145         smp_wmb();
 146 }
 147
 148 /*
 149  * Ends section changing read-only state of the superblock. After this function
 150  * returns if mnt_is_readonly() returns false, the caller will be able to
 151  * observe all the changes remount did to the superblock.
 152  */
 153 static inline void sb_end_ro_state_change(struct super_block *sb)
 154 {
 155         /*
 156          * This barrier provides release semantics that pairs with
 157          * the smp_rmb() acquire semantics in mnt_is_readonly().
 158          * This barrier pair ensure that when mnt_is_readonly() sees
 159          * 0 for sb->s_readonly_remount, it will also see all the
 160          * preceding flag changes that were made during the RO state
 161          * change.
 162          */
 163         smp_wmb();
 164         WRITE_ONCE(sb->s_readonly_remount, 0);
 165 }
 166
 167 /*
 168  * open.c
 169  */
 170 struct open_flags {
 171         int open_flag;
 172         umode_t mode;
 173         int acc_mode;
 174         int intent;
 175         int lookup_flags;
 176 };
 177 extern struct file *do_filp_open(int dfd, struct filename *pathname,
 178                 const struct open_flags *op);
 179 extern struct file *do_file_open_root(const struct path *,
 180                 const char *, const struct open_flags *);
 181 extern struct open_how build_open_how(int flags, umode_t mode);
 182 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
 183 extern struct file *__close_fd_get_file(unsigned int fd);
 184
 185 long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 186 int chmod_common(const struct path *path, umode_t mode);
 187 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
 188                 int flag);
 189 int chown_common(const struct path *path, uid_t user, gid_t group);
 190 extern int vfs_open(const struct path *, struct file *);
 191
 192 /*
 193  * inode.c
 194  */
 195 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
 196 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
 197 bool in_group_or_capable(struct mnt_idmap *idmap,
 198                          const struct inode *inode, vfsgid_t vfsgid);
 199 void lock_two_inodes(struct inode *inode1, struct inode *inode2,
 200                      unsigned subclass1, unsigned subclass2);
 201
 202 /*
 203  * fs-writeback.c
 204  */
 205 extern long get_nr_dirty_inodes(void);
 206 void invalidate_inodes(struct super_block *sb);
 207
 208 /*
 209  * dcache.c
 210  */
 211 extern int d_set_mounted(struct dentry *dentry);
 212 extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
 213 extern struct dentry *d_alloc_cursor(struct dentry *);
 214 extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
 215 extern char *simple_dname(struct dentry *, char *, int);
 216 extern void dput_to_list(struct dentry *, struct list_head *);
 217 extern void shrink_dentry_list(struct list_head *);
 218
 219 /*
 220  * pipe.c
 221  */
 222 extern const struct file_operations pipefifo_fops;
 223
 224 /*
 225  * fs_pin.c
 226  */
 227 extern void group_pin_kill(struct hlist_head *p);
 228 extern void mnt_pin_kill(struct mount *m);
 229
 230 /*
 231  * fs/nsfs.c
 232  */
 233 extern const struct dentry_operations ns_dentry_operations;
 234
 235 /*
 236  * fs/stat.c:
 237  */
 238
 239 int getname_statx_lookup_flags(int flags);
 240 int do_statx(int dfd, struct filename *filename, unsigned int flags,
 241              unsigned int mask, struct statx __user *buffer);
 242
 243 /*
 244  * fs/splice.c:
 245  */
 246 long splice_file_to_pipe(struct file *in,
 247                          struct pipe_inode_info *opipe,
 248                          loff_t *offset,
 249                          size_t len, unsigned int flags);
 250
 251 /*
 252  * fs/xattr.c:
 253  */
 254 struct xattr_name {
 255         char name[XATTR_NAME_MAX + 1];
 256 };
 257
 258 struct xattr_ctx {
 259         /* Value of attribute */
 260         union {
 261                 const void __user *cvalue;
 262                 void __user *value;
 263         };
 264         void *kvalue;
 265         size_t size;
 266         /* Attribute name */
 267         struct xattr_name *kname;
 268         unsigned int flags;
 269 };
 270
 271
 272 ssize_t do_getxattr(struct mnt_idmap *idmap,
 273                     struct dentry *d,
 274                     struct xattr_ctx *ctx);
 275
 276 int setxattr_copy(const char __user *name, struct xattr_ctx *ctx);
 277 int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 278                 struct xattr_ctx *ctx);
 279 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
 280
 281 #ifdef CONFIG_FS_POSIX_ACL
 282 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 283                const char *acl_name, const void *kvalue, size_t size);
 284 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 285                    const char *acl_name, void *kvalue, size_t size);
 286 #else
 287 static inline int do_set_acl(struct mnt_idmap *idmap,
 288                              struct dentry *dentry, const char *acl_name,
 289                              const void *kvalue, size_t size)
 290 {
 291         return -EOPNOTSUPP;
 292 }
 293 static inline ssize_t do_get_acl(struct mnt_idmap *idmap,
 294                                  struct dentry *dentry, const char *acl_name,
 295                                  void *kvalue, size_t size)
 296 {
 297         return -EOPNOTSUPP;
 298 }
 299 #endif
 300
 301 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
 302
 303 /*
 304  * fs/attr.c
 305  */
 306 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
 307 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
 308 void mnt_idmap_put(struct mnt_idmap *idmap);