1 /* 2 * 3 * Copyright (C) 2011 Novell Inc. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 as published by 7 * the Free Software Foundation. 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/uuid.h> 12 13 enum ovl_path_type { 14 __OVL_PATH_UPPER = (1 << 0), 15 __OVL_PATH_MERGE = (1 << 1), 16 __OVL_PATH_ORIGIN = (1 << 2), 17 }; 18 19 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) 20 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) 21 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) 22 23 #define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay." 24 #define OVL_XATTR_OPAQUE OVL_XATTR_PREFIX "opaque" 25 #define OVL_XATTR_REDIRECT OVL_XATTR_PREFIX "redirect" 26 #define OVL_XATTR_ORIGIN OVL_XATTR_PREFIX "origin" 27 #define OVL_XATTR_IMPURE OVL_XATTR_PREFIX "impure" 28 29 /* 30 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, 31 * where: 32 * origin.fh - exported file handle of the lower file 33 * origin.uuid - uuid of the lower filesystem 34 */ 35 #define OVL_FH_VERSION 0 36 #define OVL_FH_MAGIC 0xfb 37 38 /* CPU byte order required for fid decoding: */ 39 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) 40 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) 41 42 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN) 43 44 #if defined(__LITTLE_ENDIAN) 45 #define OVL_FH_FLAG_CPU_ENDIAN 0 46 #elif defined(__BIG_ENDIAN) 47 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN 48 #else 49 #error Endianness not defined 50 #endif 51 52 /* On-disk and in-memeory format for redirect by file handle */ 53 struct ovl_fh { 54 u8 version; /* 0 */ 55 u8 magic; /* 0xfb */ 56 u8 len; /* size of this header + size of fid */ 57 u8 flags; /* OVL_FH_FLAG_* */ 58 u8 type; /* fid_type of fid */ 59 uuid_be uuid; /* uuid of filesystem */ 60 u8 fid[0]; /* file identifier */ 61 } __packed; 62 63 #define OVL_ISUPPER_MASK 1UL 64 65 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) 66 { 67 int err = vfs_rmdir(dir, dentry); 68 pr_debug("rmdir(%pd2) = %i\n", dentry, err); 69 return err; 70 } 71 72 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) 73 { 74 int err = vfs_unlink(dir, dentry, NULL); 75 pr_debug("unlink(%pd2) = %i\n", dentry, err); 76 return err; 77 } 78 79 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, 80 struct dentry *new_dentry, bool debug) 81 { 82 int err = vfs_link(old_dentry, dir, new_dentry, NULL); 83 if (debug) { 84 pr_debug("link(%pd2, %pd2) = %i\n", 85 old_dentry, new_dentry, err); 86 } 87 return err; 88 } 89 90 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, 91 umode_t mode, bool debug) 92 { 93 int err = vfs_create(dir, dentry, mode, true); 94 if (debug) 95 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); 96 return err; 97 } 98 99 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, 100 umode_t mode, bool debug) 101 { 102 int err = vfs_mkdir(dir, dentry, mode); 103 if (debug) 104 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); 105 return err; 106 } 107 108 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, 109 umode_t mode, dev_t dev, bool debug) 110 { 111 int err = vfs_mknod(dir, dentry, mode, dev); 112 if (debug) { 113 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", 114 dentry, mode, dev, err); 115 } 116 return err; 117 } 118 119 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, 120 const char *oldname, bool debug) 121 { 122 int err = vfs_symlink(dir, dentry, oldname); 123 if (debug) 124 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); 125 return err; 126 } 127 128 static inline int ovl_do_setxattr(struct dentry *dentry, const char *name, 129 const void *value, size_t size, int flags) 130 { 131 int err = vfs_setxattr(dentry, name, value, size, flags); 132 pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n", 133 dentry, name, (int) size, (char *) value, flags, err); 134 return err; 135 } 136 137 static inline int ovl_do_removexattr(struct dentry *dentry, const char *name) 138 { 139 int err = vfs_removexattr(dentry, name); 140 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); 141 return err; 142 } 143 144 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, 145 struct inode *newdir, struct dentry *newdentry, 146 unsigned int flags) 147 { 148 int err; 149 150 pr_debug("rename(%pd2, %pd2, 0x%x)\n", 151 olddentry, newdentry, flags); 152 153 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); 154 155 if (err) { 156 pr_debug("...rename(%pd2, %pd2, ...) = %i\n", 157 olddentry, newdentry, err); 158 } 159 return err; 160 } 161 162 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) 163 { 164 int err = vfs_whiteout(dir, dentry); 165 pr_debug("whiteout(%pd2) = %i\n", dentry, err); 166 return err; 167 } 168 169 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) 170 { 171 struct dentry *ret = vfs_tmpfile(dentry, mode, 0); 172 int err = IS_ERR(ret) ? PTR_ERR(ret) : 0; 173 174 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); 175 return ret; 176 } 177 178 static inline struct inode *ovl_inode_real(struct inode *inode, bool *is_upper) 179 { 180 unsigned long x = (unsigned long) READ_ONCE(inode->i_private); 181 182 if (is_upper) 183 *is_upper = x & OVL_ISUPPER_MASK; 184 185 return (struct inode *) (x & ~OVL_ISUPPER_MASK); 186 } 187 188 /* util.c */ 189 int ovl_want_write(struct dentry *dentry); 190 void ovl_drop_write(struct dentry *dentry); 191 struct dentry *ovl_workdir(struct dentry *dentry); 192 const struct cred *ovl_override_creds(struct super_block *sb); 193 struct super_block *ovl_same_sb(struct super_block *sb); 194 struct ovl_entry *ovl_alloc_entry(unsigned int numlower); 195 bool ovl_dentry_remote(struct dentry *dentry); 196 bool ovl_dentry_weird(struct dentry *dentry); 197 enum ovl_path_type ovl_path_type(struct dentry *dentry); 198 void ovl_path_upper(struct dentry *dentry, struct path *path); 199 void ovl_path_lower(struct dentry *dentry, struct path *path); 200 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); 201 struct dentry *ovl_dentry_upper(struct dentry *dentry); 202 struct dentry *ovl_dentry_lower(struct dentry *dentry); 203 struct dentry *ovl_dentry_real(struct dentry *dentry); 204 struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry); 205 void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache); 206 bool ovl_dentry_is_opaque(struct dentry *dentry); 207 bool ovl_dentry_is_impure(struct dentry *dentry); 208 bool ovl_dentry_is_whiteout(struct dentry *dentry); 209 void ovl_dentry_set_opaque(struct dentry *dentry); 210 bool ovl_redirect_dir(struct super_block *sb); 211 const char *ovl_dentry_get_redirect(struct dentry *dentry); 212 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); 213 void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry); 214 void ovl_inode_init(struct inode *inode, struct inode *realinode, 215 bool is_upper); 216 void ovl_inode_update(struct inode *inode, struct inode *upperinode); 217 void ovl_dentry_version_inc(struct dentry *dentry); 218 u64 ovl_dentry_version_get(struct dentry *dentry); 219 bool ovl_is_whiteout(struct dentry *dentry); 220 struct file *ovl_path_open(struct path *path, int flags); 221 int ovl_copy_up_start(struct dentry *dentry); 222 void ovl_copy_up_end(struct dentry *dentry); 223 bool ovl_check_dir_xattr(struct dentry *dentry, const char *name); 224 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 225 const char *name, const void *value, size_t size, 226 int xerr); 227 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); 228 229 static inline bool ovl_is_impuredir(struct dentry *dentry) 230 { 231 return ovl_check_dir_xattr(dentry, OVL_XATTR_IMPURE); 232 } 233 234 235 /* namei.c */ 236 int ovl_path_next(int idx, struct dentry *dentry, struct path *path); 237 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags); 238 bool ovl_lower_positive(struct dentry *dentry); 239 240 /* readdir.c */ 241 extern const struct file_operations ovl_dir_operations; 242 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); 243 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); 244 void ovl_cache_free(struct list_head *list); 245 int ovl_check_d_type_supported(struct path *realpath); 246 void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, 247 struct dentry *dentry, int level); 248 249 /* inode.c */ 250 int ovl_setattr(struct dentry *dentry, struct iattr *attr); 251 int ovl_getattr(const struct path *path, struct kstat *stat, 252 u32 request_mask, unsigned int flags); 253 int ovl_permission(struct inode *inode, int mask); 254 int ovl_xattr_set(struct dentry *dentry, const char *name, const void *value, 255 size_t size, int flags); 256 int ovl_xattr_get(struct dentry *dentry, const char *name, 257 void *value, size_t size); 258 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); 259 struct posix_acl *ovl_get_acl(struct inode *inode, int type); 260 int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags); 261 int ovl_update_time(struct inode *inode, struct timespec *ts, int flags); 262 bool ovl_is_private_xattr(const char *name); 263 264 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); 265 struct inode *ovl_get_inode(struct super_block *sb, struct inode *realinode); 266 static inline void ovl_copyattr(struct inode *from, struct inode *to) 267 { 268 to->i_uid = from->i_uid; 269 to->i_gid = from->i_gid; 270 to->i_mode = from->i_mode; 271 to->i_atime = from->i_atime; 272 to->i_mtime = from->i_mtime; 273 to->i_ctime = from->i_ctime; 274 } 275 276 /* dir.c */ 277 extern const struct inode_operations ovl_dir_inode_operations; 278 struct dentry *ovl_lookup_temp(struct dentry *workdir); 279 struct cattr { 280 dev_t rdev; 281 umode_t mode; 282 const char *link; 283 }; 284 int ovl_create_real(struct inode *dir, struct dentry *newdentry, 285 struct cattr *attr, 286 struct dentry *hardlink, bool debug); 287 void ovl_cleanup(struct inode *dir, struct dentry *dentry); 288 289 /* copy_up.c */ 290 int ovl_copy_up(struct dentry *dentry); 291 int ovl_copy_up_flags(struct dentry *dentry, int flags); 292 int ovl_copy_xattr(struct dentry *old, struct dentry *new); 293 int ovl_set_attr(struct dentry *upper, struct kstat *stat); 294