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0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  *
0004  * Copyright (C) 2011 Novell Inc.
0005  */
0006 
0007 #include <linux/kernel.h>
0008 #include <linux/uuid.h>
0009 #include <linux/fs.h>
0010 #include <linux/namei.h>
0011 #include "ovl_entry.h"
0012 
0013 #undef pr_fmt
0014 #define pr_fmt(fmt) "overlayfs: " fmt
0015 
0016 enum ovl_path_type {
0017     __OVL_PATH_UPPER    = (1 << 0),
0018     __OVL_PATH_MERGE    = (1 << 1),
0019     __OVL_PATH_ORIGIN   = (1 << 2),
0020 };
0021 
0022 #define OVL_TYPE_UPPER(type)    ((type) & __OVL_PATH_UPPER)
0023 #define OVL_TYPE_MERGE(type)    ((type) & __OVL_PATH_MERGE)
0024 #define OVL_TYPE_ORIGIN(type)   ((type) & __OVL_PATH_ORIGIN)
0025 
0026 #define OVL_XATTR_NAMESPACE "overlay."
0027 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
0028 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
0029 
0030 enum ovl_xattr {
0031     OVL_XATTR_OPAQUE,
0032     OVL_XATTR_REDIRECT,
0033     OVL_XATTR_ORIGIN,
0034     OVL_XATTR_IMPURE,
0035     OVL_XATTR_NLINK,
0036     OVL_XATTR_UPPER,
0037     OVL_XATTR_METACOPY,
0038     OVL_XATTR_PROTATTR,
0039 };
0040 
0041 enum ovl_inode_flag {
0042     /* Pure upper dir that may contain non pure upper entries */
0043     OVL_IMPURE,
0044     /* Non-merge dir that may contain whiteout entries */
0045     OVL_WHITEOUTS,
0046     OVL_INDEX,
0047     OVL_UPPERDATA,
0048     /* Inode number will remain constant over copy up. */
0049     OVL_CONST_INO,
0050 };
0051 
0052 enum ovl_entry_flag {
0053     OVL_E_UPPER_ALIAS,
0054     OVL_E_OPAQUE,
0055     OVL_E_CONNECTED,
0056 };
0057 
0058 enum {
0059     OVL_XINO_OFF,
0060     OVL_XINO_AUTO,
0061     OVL_XINO_ON,
0062 };
0063 
0064 /*
0065  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
0066  * where:
0067  * origin.fh    - exported file handle of the lower file
0068  * origin.uuid  - uuid of the lower filesystem
0069  */
0070 #define OVL_FH_VERSION  0
0071 #define OVL_FH_MAGIC    0xfb
0072 
0073 /* CPU byte order required for fid decoding:  */
0074 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
0075 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
0076 /* Is the real inode encoded in fid an upper inode? */
0077 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
0078 
0079 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
0080              OVL_FH_FLAG_PATH_UPPER)
0081 
0082 #if defined(__LITTLE_ENDIAN)
0083 #define OVL_FH_FLAG_CPU_ENDIAN 0
0084 #elif defined(__BIG_ENDIAN)
0085 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
0086 #else
0087 #error Endianness not defined
0088 #endif
0089 
0090 /* The type used to be returned by overlay exportfs for misaligned fid */
0091 #define OVL_FILEID_V0   0xfb
0092 /* The type returned by overlay exportfs for 32bit aligned fid */
0093 #define OVL_FILEID_V1   0xf8
0094 
0095 /* On-disk format for "origin" file handle */
0096 struct ovl_fb {
0097     u8 version; /* 0 */
0098     u8 magic;   /* 0xfb */
0099     u8 len;     /* size of this header + size of fid */
0100     u8 flags;   /* OVL_FH_FLAG_* */
0101     u8 type;    /* fid_type of fid */
0102     uuid_t uuid;    /* uuid of filesystem */
0103     u32 fid[];  /* file identifier should be 32bit aligned in-memory */
0104 } __packed;
0105 
0106 /* In-memory and on-wire format for overlay file handle */
0107 struct ovl_fh {
0108     u8 padding[3];  /* make sure fb.fid is 32bit aligned */
0109     union {
0110         struct ovl_fb fb;
0111         u8 buf[0];
0112     };
0113 } __packed;
0114 
0115 #define OVL_FH_WIRE_OFFSET  offsetof(struct ovl_fh, fb)
0116 #define OVL_FH_LEN(fh)      (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
0117 #define OVL_FH_FID_OFFSET   (OVL_FH_WIRE_OFFSET + \
0118                  offsetof(struct ovl_fb, fid))
0119 
0120 extern const char *const ovl_xattr_table[][2];
0121 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
0122 {
0123     return ovl_xattr_table[ox][ofs->config.userxattr];
0124 }
0125 
0126 /*
0127  * When changing ownership of an upper object map the intended ownership
0128  * according to the upper layer's idmapping. When an upper mount idmaps files
0129  * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
0130  * this object will report it as being owned by id 1000 when calling stat via
0131  * the upper mount.
0132  * In order to change ownership of an object so stat reports id 1000 when
0133  * called on an idmapped upper mount the value written to disk - i.e., the
0134  * value stored in ia_*id - must 1001. The mount mapping helper will thus take
0135  * care to map 1000 to 1001.
0136  * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
0137  */
0138 static inline int ovl_do_notify_change(struct ovl_fs *ofs,
0139                        struct dentry *upperdentry,
0140                        struct iattr *attr)
0141 {
0142     return notify_change(ovl_upper_mnt_userns(ofs), upperdentry, attr, NULL);
0143 }
0144 
0145 static inline int ovl_do_rmdir(struct ovl_fs *ofs,
0146                    struct inode *dir, struct dentry *dentry)
0147 {
0148     int err = vfs_rmdir(ovl_upper_mnt_userns(ofs), dir, dentry);
0149 
0150     pr_debug("rmdir(%pd2) = %i\n", dentry, err);
0151     return err;
0152 }
0153 
0154 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
0155                 struct dentry *dentry)
0156 {
0157     int err = vfs_unlink(ovl_upper_mnt_userns(ofs), dir, dentry, NULL);
0158 
0159     pr_debug("unlink(%pd2) = %i\n", dentry, err);
0160     return err;
0161 }
0162 
0163 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
0164                   struct inode *dir, struct dentry *new_dentry)
0165 {
0166     int err = vfs_link(old_dentry, ovl_upper_mnt_userns(ofs), dir, new_dentry, NULL);
0167 
0168     pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
0169     return err;
0170 }
0171 
0172 static inline int ovl_do_create(struct ovl_fs *ofs,
0173                 struct inode *dir, struct dentry *dentry,
0174                 umode_t mode)
0175 {
0176     int err = vfs_create(ovl_upper_mnt_userns(ofs), dir, dentry, mode, true);
0177 
0178     pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
0179     return err;
0180 }
0181 
0182 static inline int ovl_do_mkdir(struct ovl_fs *ofs,
0183                    struct inode *dir, struct dentry *dentry,
0184                    umode_t mode)
0185 {
0186     int err = vfs_mkdir(ovl_upper_mnt_userns(ofs), dir, dentry, mode);
0187     pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
0188     return err;
0189 }
0190 
0191 static inline int ovl_do_mknod(struct ovl_fs *ofs,
0192                    struct inode *dir, struct dentry *dentry,
0193                    umode_t mode, dev_t dev)
0194 {
0195     int err = vfs_mknod(ovl_upper_mnt_userns(ofs), dir, dentry, mode, dev);
0196 
0197     pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
0198     return err;
0199 }
0200 
0201 static inline int ovl_do_symlink(struct ovl_fs *ofs,
0202                  struct inode *dir, struct dentry *dentry,
0203                  const char *oldname)
0204 {
0205     int err = vfs_symlink(ovl_upper_mnt_userns(ofs), dir, dentry, oldname);
0206 
0207     pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
0208     return err;
0209 }
0210 
0211 static inline ssize_t ovl_do_getxattr(struct path *path, const char *name,
0212                       void *value, size_t size)
0213 {
0214     int err, len;
0215 
0216     WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
0217 
0218     err = vfs_getxattr(mnt_user_ns(path->mnt), path->dentry,
0219                    name, value, size);
0220     len = (value && err > 0) ? err : 0;
0221 
0222     pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
0223          path->dentry, name, min(len, 48), value, size, err);
0224     return err;
0225 }
0226 
0227 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
0228                      struct dentry *upperdentry,
0229                      enum ovl_xattr ox, void *value,
0230                      size_t size)
0231 {
0232     struct path upperpath = {
0233         .dentry = upperdentry,
0234         .mnt = ovl_upper_mnt(ofs),
0235     };
0236 
0237     return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
0238 }
0239 
0240 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
0241                      struct path *path,
0242                      enum ovl_xattr ox, void *value,
0243                      size_t size)
0244 {
0245     return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
0246 }
0247 
0248 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
0249                   const char *name, const void *value,
0250                   size_t size, int flags)
0251 {
0252     int err = vfs_setxattr(ovl_upper_mnt_userns(ofs), dentry, name,
0253                    (void *)value, size, flags);
0254 
0255     pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
0256          dentry, name, min((int)size, 48), value, size, flags, err);
0257     return err;
0258 }
0259 
0260 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
0261                    enum ovl_xattr ox, const void *value,
0262                    size_t size)
0263 {
0264     return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
0265 }
0266 
0267 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
0268                      const char *name)
0269 {
0270     int err = vfs_removexattr(ovl_upper_mnt_userns(ofs), dentry, name);
0271     pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
0272     return err;
0273 }
0274 
0275 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
0276                   enum ovl_xattr ox)
0277 {
0278     return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
0279 }
0280 
0281 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
0282                 struct dentry *olddentry, struct inode *newdir,
0283                 struct dentry *newdentry, unsigned int flags)
0284 {
0285     int err;
0286     struct renamedata rd = {
0287         .old_mnt_userns = ovl_upper_mnt_userns(ofs),
0288         .old_dir    = olddir,
0289         .old_dentry     = olddentry,
0290         .new_mnt_userns = ovl_upper_mnt_userns(ofs),
0291         .new_dir    = newdir,
0292         .new_dentry     = newdentry,
0293         .flags      = flags,
0294     };
0295 
0296     pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
0297     err = vfs_rename(&rd);
0298     if (err) {
0299         pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
0300              olddentry, newdentry, err);
0301     }
0302     return err;
0303 }
0304 
0305 static inline int ovl_do_whiteout(struct ovl_fs *ofs,
0306                   struct inode *dir, struct dentry *dentry)
0307 {
0308     int err = vfs_whiteout(ovl_upper_mnt_userns(ofs), dir, dentry);
0309     pr_debug("whiteout(%pd2) = %i\n", dentry, err);
0310     return err;
0311 }
0312 
0313 static inline struct dentry *ovl_do_tmpfile(struct ovl_fs *ofs,
0314                         struct dentry *dentry, umode_t mode)
0315 {
0316     struct dentry *ret = vfs_tmpfile(ovl_upper_mnt_userns(ofs), dentry, mode, 0);
0317     int err = PTR_ERR_OR_ZERO(ret);
0318 
0319     pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
0320     return ret;
0321 }
0322 
0323 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
0324                           const char *name,
0325                           struct dentry *base, int len)
0326 {
0327     return lookup_one(ovl_upper_mnt_userns(ofs), name, base, len);
0328 }
0329 
0330 static inline bool ovl_open_flags_need_copy_up(int flags)
0331 {
0332     if (!flags)
0333         return false;
0334 
0335     return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
0336 }
0337 
0338 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
0339 {
0340     /*
0341      * To avoid regressions in existing setups with overlay lower offline
0342      * changes, we allow lower changes only if none of the new features
0343      * are used.
0344      */
0345     return (!ofs->config.index && !ofs->config.metacopy &&
0346         !ofs->config.redirect_dir && ofs->config.xino != OVL_XINO_ON);
0347 }
0348 
0349 
0350 /* util.c */
0351 int ovl_want_write(struct dentry *dentry);
0352 void ovl_drop_write(struct dentry *dentry);
0353 struct dentry *ovl_workdir(struct dentry *dentry);
0354 const struct cred *ovl_override_creds(struct super_block *sb);
0355 int ovl_can_decode_fh(struct super_block *sb);
0356 struct dentry *ovl_indexdir(struct super_block *sb);
0357 bool ovl_index_all(struct super_block *sb);
0358 bool ovl_verify_lower(struct super_block *sb);
0359 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
0360 bool ovl_dentry_remote(struct dentry *dentry);
0361 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
0362                  unsigned int mask);
0363 bool ovl_dentry_weird(struct dentry *dentry);
0364 enum ovl_path_type ovl_path_type(struct dentry *dentry);
0365 void ovl_path_upper(struct dentry *dentry, struct path *path);
0366 void ovl_path_lower(struct dentry *dentry, struct path *path);
0367 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
0368 void ovl_i_path_real(struct inode *inode, struct path *path);
0369 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
0370 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
0371 struct dentry *ovl_dentry_upper(struct dentry *dentry);
0372 struct dentry *ovl_dentry_lower(struct dentry *dentry);
0373 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
0374 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
0375 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
0376 struct dentry *ovl_dentry_real(struct dentry *dentry);
0377 struct dentry *ovl_i_dentry_upper(struct inode *inode);
0378 struct inode *ovl_inode_upper(struct inode *inode);
0379 struct inode *ovl_inode_lower(struct inode *inode);
0380 struct inode *ovl_inode_lowerdata(struct inode *inode);
0381 struct inode *ovl_inode_real(struct inode *inode);
0382 struct inode *ovl_inode_realdata(struct inode *inode);
0383 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
0384 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
0385 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
0386 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
0387 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
0388 bool ovl_dentry_is_opaque(struct dentry *dentry);
0389 bool ovl_dentry_is_whiteout(struct dentry *dentry);
0390 void ovl_dentry_set_opaque(struct dentry *dentry);
0391 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
0392 void ovl_dentry_set_upper_alias(struct dentry *dentry);
0393 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
0394 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
0395 bool ovl_has_upperdata(struct inode *inode);
0396 void ovl_set_upperdata(struct inode *inode);
0397 bool ovl_redirect_dir(struct super_block *sb);
0398 const char *ovl_dentry_get_redirect(struct dentry *dentry);
0399 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
0400 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
0401 void ovl_dir_modified(struct dentry *dentry, bool impurity);
0402 u64 ovl_dentry_version_get(struct dentry *dentry);
0403 bool ovl_is_whiteout(struct dentry *dentry);
0404 struct file *ovl_path_open(struct path *path, int flags);
0405 int ovl_copy_up_start(struct dentry *dentry, int flags);
0406 void ovl_copy_up_end(struct dentry *dentry);
0407 bool ovl_already_copied_up(struct dentry *dentry, int flags);
0408 bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, struct path *path,
0409                   enum ovl_xattr ox);
0410 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, struct path *path);
0411 
0412 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
0413                       struct dentry *upperdentry)
0414 {
0415     struct path upperpath = {
0416         .dentry = upperdentry,
0417         .mnt = ovl_upper_mnt(ofs),
0418     };
0419     return ovl_path_check_origin_xattr(ofs, &upperpath);
0420 }
0421 
0422 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
0423                enum ovl_xattr ox, const void *value, size_t size,
0424                int xerr);
0425 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
0426 bool ovl_inuse_trylock(struct dentry *dentry);
0427 void ovl_inuse_unlock(struct dentry *dentry);
0428 bool ovl_is_inuse(struct dentry *dentry);
0429 bool ovl_need_index(struct dentry *dentry);
0430 int ovl_nlink_start(struct dentry *dentry);
0431 void ovl_nlink_end(struct dentry *dentry);
0432 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
0433 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct path *path);
0434 bool ovl_is_metacopy_dentry(struct dentry *dentry);
0435 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct path *path, int padding);
0436 int ovl_sync_status(struct ovl_fs *ofs);
0437 
0438 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
0439 {
0440     set_bit(flag, &OVL_I(inode)->flags);
0441 }
0442 
0443 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
0444 {
0445     clear_bit(flag, &OVL_I(inode)->flags);
0446 }
0447 
0448 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
0449 {
0450     return test_bit(flag, &OVL_I(inode)->flags);
0451 }
0452 
0453 static inline bool ovl_is_impuredir(struct super_block *sb,
0454                     struct dentry *upperdentry)
0455 {
0456     struct ovl_fs *ofs = OVL_FS(sb);
0457     struct path upperpath = {
0458         .dentry = upperdentry,
0459         .mnt = ovl_upper_mnt(ofs),
0460     };
0461 
0462     return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
0463 }
0464 
0465 /*
0466  * With xino=auto, we do best effort to keep all inodes on same st_dev and
0467  * d_ino consistent with st_ino.
0468  * With xino=on, we do the same effort but we warn if we failed.
0469  */
0470 static inline bool ovl_xino_warn(struct super_block *sb)
0471 {
0472     return OVL_FS(sb)->config.xino == OVL_XINO_ON;
0473 }
0474 
0475 /* All layers on same fs? */
0476 static inline bool ovl_same_fs(struct super_block *sb)
0477 {
0478     return OVL_FS(sb)->xino_mode == 0;
0479 }
0480 
0481 /* All overlay inodes have same st_dev? */
0482 static inline bool ovl_same_dev(struct super_block *sb)
0483 {
0484     return OVL_FS(sb)->xino_mode >= 0;
0485 }
0486 
0487 static inline unsigned int ovl_xino_bits(struct super_block *sb)
0488 {
0489     return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
0490 }
0491 
0492 static inline void ovl_inode_lock(struct inode *inode)
0493 {
0494     mutex_lock(&OVL_I(inode)->lock);
0495 }
0496 
0497 static inline int ovl_inode_lock_interruptible(struct inode *inode)
0498 {
0499     return mutex_lock_interruptible(&OVL_I(inode)->lock);
0500 }
0501 
0502 static inline void ovl_inode_unlock(struct inode *inode)
0503 {
0504     mutex_unlock(&OVL_I(inode)->lock);
0505 }
0506 
0507 
0508 /* namei.c */
0509 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
0510 
0511 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
0512 {
0513     if (fh_len < sizeof(struct ovl_fh))
0514         return -EINVAL;
0515 
0516     return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
0517 }
0518 
0519 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
0520                   struct vfsmount *mnt, bool connected);
0521 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
0522             struct dentry *upperdentry, struct ovl_path **stackp);
0523 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
0524               enum ovl_xattr ox, struct dentry *real, bool is_upper,
0525               bool set);
0526 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
0527 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
0528 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
0529                struct qstr *name);
0530 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
0531 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
0532                 struct dentry *origin, bool verify);
0533 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
0534 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
0535               unsigned int flags);
0536 bool ovl_lower_positive(struct dentry *dentry);
0537 
0538 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
0539                     struct dentry *origin, bool set)
0540 {
0541     return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
0542                  false, set);
0543 }
0544 
0545 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
0546                    struct dentry *upper, bool set)
0547 {
0548     return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
0549 }
0550 
0551 /* readdir.c */
0552 extern const struct file_operations ovl_dir_operations;
0553 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
0554 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
0555 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
0556                struct list_head *list);
0557 void ovl_cache_free(struct list_head *list);
0558 void ovl_dir_cache_free(struct inode *inode);
0559 int ovl_check_d_type_supported(struct path *realpath);
0560 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
0561             struct vfsmount *mnt, struct dentry *dentry, int level);
0562 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
0563 
0564 /*
0565  * Can we iterate real dir directly?
0566  *
0567  * Non-merge dir may contain whiteouts from a time it was a merge upper, before
0568  * lower dir was removed under it and possibly before it was rotated from upper
0569  * to lower layer.
0570  */
0571 static inline bool ovl_dir_is_real(struct dentry *dir)
0572 {
0573     return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
0574 }
0575 
0576 /* inode.c */
0577 int ovl_set_nlink_upper(struct dentry *dentry);
0578 int ovl_set_nlink_lower(struct dentry *dentry);
0579 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
0580                struct dentry *upperdentry,
0581                unsigned int fallback);
0582 int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
0583         struct iattr *attr);
0584 int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path,
0585         struct kstat *stat, u32 request_mask, unsigned int flags);
0586 int ovl_permission(struct user_namespace *mnt_userns, struct inode *inode,
0587            int mask);
0588 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
0589           const void *value, size_t size, int flags);
0590 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
0591           void *value, size_t size);
0592 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
0593 
0594 #ifdef CONFIG_FS_POSIX_ACL
0595 struct posix_acl *ovl_get_acl(struct inode *inode, int type, bool rcu);
0596 #else
0597 #define ovl_get_acl NULL
0598 #endif
0599 
0600 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
0601 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
0602 
0603 struct ovl_inode_params {
0604     struct inode *newinode;
0605     struct dentry *upperdentry;
0606     struct ovl_path *lowerpath;
0607     bool index;
0608     unsigned int numlower;
0609     char *redirect;
0610     struct dentry *lowerdata;
0611 };
0612 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
0613             unsigned long ino, int fsid);
0614 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
0615 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
0616                    bool is_upper);
0617 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
0618 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
0619 struct inode *ovl_get_inode(struct super_block *sb,
0620                 struct ovl_inode_params *oip);
0621 void ovl_copyattr(struct inode *to);
0622 
0623 /* vfs inode flags copied from real to ovl inode */
0624 #define OVL_COPY_I_FLAGS_MASK   (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
0625 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
0626 #define OVL_PROT_I_FLAGS_MASK   (S_APPEND | S_IMMUTABLE)
0627 
0628 /*
0629  * fileattr flags copied from lower to upper inode on copy up.
0630  * We cannot copy up immutable/append-only flags, because that would prevent
0631  * linking temp inode to upper dir, so we store them in xattr instead.
0632  */
0633 #define OVL_COPY_FS_FLAGS_MASK  (FS_SYNC_FL | FS_NOATIME_FL)
0634 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
0635 #define OVL_PROT_FS_FLAGS_MASK  (FS_APPEND_FL | FS_IMMUTABLE_FL)
0636 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
0637 
0638 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
0639 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
0640               struct fileattr *fa);
0641 
0642 static inline void ovl_copyflags(struct inode *from, struct inode *to)
0643 {
0644     unsigned int mask = OVL_COPY_I_FLAGS_MASK;
0645 
0646     inode_set_flags(to, from->i_flags & mask, mask);
0647 }
0648 
0649 /* dir.c */
0650 extern const struct inode_operations ovl_dir_inode_operations;
0651 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
0652                  struct dentry *dentry);
0653 struct ovl_cattr {
0654     dev_t rdev;
0655     umode_t mode;
0656     const char *link;
0657     struct dentry *hardlink;
0658 };
0659 
0660 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
0661 
0662 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
0663            struct dentry **newdentry, umode_t mode);
0664 struct dentry *ovl_create_real(struct ovl_fs *ofs,
0665                    struct inode *dir, struct dentry *newdentry,
0666                    struct ovl_cattr *attr);
0667 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
0668 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
0669 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
0670                    struct ovl_cattr *attr);
0671 
0672 /* file.c */
0673 extern const struct file_operations ovl_file_operations;
0674 int __init ovl_aio_request_cache_init(void);
0675 void ovl_aio_request_cache_destroy(void);
0676 int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa);
0677 int ovl_real_fileattr_set(struct path *realpath, struct fileattr *fa);
0678 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
0679 int ovl_fileattr_set(struct user_namespace *mnt_userns,
0680              struct dentry *dentry, struct fileattr *fa);
0681 
0682 /* copy_up.c */
0683 int ovl_copy_up(struct dentry *dentry);
0684 int ovl_copy_up_with_data(struct dentry *dentry);
0685 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
0686 int ovl_copy_xattr(struct super_block *sb, struct path *path, struct dentry *new);
0687 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
0688 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
0689                   bool is_upper);
0690 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
0691            struct dentry *upper);
0692 
0693 /* export.c */
0694 extern const struct export_operations ovl_export_operations;
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