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 int show_path(struct seq_file *m, struct dentry *root);
  87
  88 /*
  89  * fs_struct.c
  90  */
  91 extern void chroot_fs_refs(const struct path *, const struct path *);
  92
  93 /*
  94  * file_table.c
  95  */
  96 struct file *alloc_empty_file(int flags, const struct cred *cred);
  97 struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred);
  98 struct file *alloc_empty_backing_file(int flags, const struct cred *cred);
  99
 100 static inline void file_put_write_access(struct file *file)
 101 {
 102         put_write_access(file->f_inode);
 103         mnt_put_write_access(file->f_path.mnt);
 104         if (unlikely(file->f_mode & FMODE_BACKING))
 105                 mnt_put_write_access(backing_file_user_path(file)->mnt);
 106 }
 107
 108 static inline void put_file_access(struct file *file)
 109 {
 110         if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
 111                 i_readcount_dec(file->f_inode);
 112         } else if (file->f_mode & FMODE_WRITER) {
 113                 file_put_write_access(file);
 114         }
 115 }
 116
 117 /*
 118  * super.c
 119  */
 120 extern int reconfigure_super(struct fs_context *);
 121 extern bool super_trylock_shared(struct super_block *sb);
 122 struct super_block *user_get_super(dev_t, bool excl);
 123 void put_super(struct super_block *sb);
 124 extern bool mount_capable(struct fs_context *);
 125 int sb_init_dio_done_wq(struct super_block *sb);
 126
 127 /*
 128  * Prepare superblock for changing its read-only state (i.e., either remount
 129  * read-write superblock read-only or vice versa). After this function returns
 130  * mnt_is_readonly() will return true for any mount of the superblock if its
 131  * caller is able to observe any changes done by the remount. This holds until
 132  * sb_end_ro_state_change() is called.
 133  */
 134 static inline void sb_start_ro_state_change(struct super_block *sb)
 135 {
 136         WRITE_ONCE(sb->s_readonly_remount, 1);
 137         /*
 138          * For RO->RW transition, the barrier pairs with the barrier in
 139          * mnt_is_readonly() making sure if mnt_is_readonly() sees SB_RDONLY
 140          * cleared, it will see s_readonly_remount set.
 141          * For RW->RO transition, the barrier pairs with the barrier in
 142          * mnt_get_write_access() before the mnt_is_readonly() check.
 143          * The barrier makes sure if mnt_get_write_access() sees MNT_WRITE_HOLD
 144          * already cleared, it will see s_readonly_remount set.
 145          */
 146         smp_wmb();
 147 }
 148
 149 /*
 150  * Ends section changing read-only state of the superblock. After this function
 151  * returns if mnt_is_readonly() returns false, the caller will be able to
 152  * observe all the changes remount did to the superblock.
 153  */
 154 static inline void sb_end_ro_state_change(struct super_block *sb)
 155 {
 156         /*
 157          * This barrier provides release semantics that pairs with
 158          * the smp_rmb() acquire semantics in mnt_is_readonly().
 159          * This barrier pair ensure that when mnt_is_readonly() sees
 160          * 0 for sb->s_readonly_remount, it will also see all the
 161          * preceding flag changes that were made during the RO state
 162          * change.
 163          */
 164         smp_wmb();
 165         WRITE_ONCE(sb->s_readonly_remount, 0);
 166 }
 167
 168 /*
 169  * open.c
 170  */
 171 struct open_flags {
 172         int open_flag;
 173         umode_t mode;
 174         int acc_mode;
 175         int intent;
 176         int lookup_flags;
 177 };
 178 extern struct file *do_filp_open(int dfd, struct filename *pathname,
 179                 const struct open_flags *op);
 180 extern struct file *do_file_open_root(const struct path *,
 181                 const char *, const struct open_flags *);
 182 extern struct open_how build_open_how(int flags, umode_t mode);
 183 extern int build_open_flags(const struct open_how *how, struct open_flags *op);
 184 struct file *file_close_fd_locked(struct files_struct *files, unsigned fd);
 185
 186 long do_ftruncate(struct file *file, loff_t length, int small);
 187 long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
 188 int chmod_common(const struct path *path, umode_t mode);
 189 int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
 190                 int flag);
 191 int chown_common(const struct path *path, uid_t user, gid_t group);
 192 extern int vfs_open(const struct path *, struct file *);
 193
 194 /*
 195  * inode.c
 196  */
 197 extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
 198 int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
 199 bool in_group_or_capable(struct mnt_idmap *idmap,
 200                          const struct inode *inode, vfsgid_t vfsgid);
 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 extern void shrink_dcache_for_umount(struct super_block *);
 219 extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *);
 220 extern struct dentry *__d_lookup_rcu(const struct dentry *parent,
 221                                 const struct qstr *name, unsigned *seq);
 222 extern void d_genocide(struct dentry *);
 223
 224 /*
 225  * pipe.c
 226  */
 227 extern const struct file_operations pipefifo_fops;
 228
 229 /*
 230  * fs_pin.c
 231  */
 232 extern void group_pin_kill(struct hlist_head *p);
 233 extern void mnt_pin_kill(struct mount *m);
 234
 235 /*
 236  * fs/nsfs.c
 237  */
 238 extern const struct dentry_operations ns_dentry_operations;
 239
 240 /*
 241  * fs/stat.c:
 242  */
 243
 244 int getname_statx_lookup_flags(int flags);
 245 int do_statx(int dfd, struct filename *filename, unsigned int flags,
 246              unsigned int mask, struct statx __user *buffer);
 247
 248 /*
 249  * fs/splice.c:
 250  */
 251 ssize_t splice_file_to_pipe(struct file *in,
 252                             struct pipe_inode_info *opipe,
 253                             loff_t *offset,
 254                             size_t len, unsigned int flags);
 255
 256 /*
 257  * fs/xattr.c:
 258  */
 259 struct xattr_name {
 260         char name[XATTR_NAME_MAX + 1];
 261 };
 262
 263 struct xattr_ctx {
 264         /* Value of attribute */
 265         union {
 266                 const void __user *cvalue;
 267                 void __user *value;
 268         };
 269         void *kvalue;
 270         size_t size;
 271         /* Attribute name */
 272         struct xattr_name *kname;
 273         unsigned int flags;
 274 };
 275
 276
 277 ssize_t do_getxattr(struct mnt_idmap *idmap,
 278                     struct dentry *d,
 279                     struct xattr_ctx *ctx);
 280
 281 int setxattr_copy(const char __user *name, struct xattr_ctx *ctx);
 282 int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry,
 283                 struct xattr_ctx *ctx);
 284 int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode);
 285
 286 #ifdef CONFIG_FS_POSIX_ACL
 287 int do_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 288                const char *acl_name, const void *kvalue, size_t size);
 289 ssize_t do_get_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 290                    const char *acl_name, void *kvalue, size_t size);
 291 #else
 292 static inline int do_set_acl(struct mnt_idmap *idmap,
 293                              struct dentry *dentry, const char *acl_name,
 294                              const void *kvalue, size_t size)
 295 {
 296         return -EOPNOTSUPP;
 297 }
 298 static inline ssize_t do_get_acl(struct mnt_idmap *idmap,
 299                                  struct dentry *dentry, const char *acl_name,
 300                                  void *kvalue, size_t size)
 301 {
 302         return -EOPNOTSUPP;
 303 }
 304 #endif
 305
 306 ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos);
 307
 308 /*
 309  * fs/attr.c
 310  */
 311 struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns);
 312 struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
 313 void mnt_idmap_put(struct mnt_idmap *idmap);
 314 struct stashed_operations {
 315         void (*put_data)(void *data);
 316         int (*init_inode)(struct inode *inode, void *data);
 317 };
 318 int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
 319                       struct path *path);
 320 void stashed_dentry_prune(struct dentry *dentry);