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