1e9be9d5eSMiklos Szeredi /* 2e9be9d5eSMiklos Szeredi * 3e9be9d5eSMiklos Szeredi * Copyright (C) 2011 Novell Inc. 4e9be9d5eSMiklos Szeredi * 5e9be9d5eSMiklos Szeredi * This program is free software; you can redistribute it and/or modify it 6e9be9d5eSMiklos Szeredi * under the terms of the GNU General Public License version 2 as published by 7e9be9d5eSMiklos Szeredi * the Free Software Foundation. 8e9be9d5eSMiklos Szeredi */ 9e9be9d5eSMiklos Szeredi 10e9be9d5eSMiklos Szeredi #include <linux/fs.h> 11e9be9d5eSMiklos Szeredi #include <linux/slab.h> 125b825c3aSIngo Molnar #include <linux/cred.h> 13e9be9d5eSMiklos Szeredi #include <linux/xattr.h> 145201dc44SMiklos Szeredi #include <linux/posix_acl.h> 155f8415d6SAmir Goldstein #include <linux/ratelimit.h> 16e9be9d5eSMiklos Szeredi #include "overlayfs.h" 17e9be9d5eSMiklos Szeredi 18ba1e563cSChandan Rajendra 19ba1e563cSChandan Rajendra static dev_t ovl_get_pseudo_dev(struct dentry *dentry) 20ba1e563cSChandan Rajendra { 21ba1e563cSChandan Rajendra struct ovl_entry *oe = dentry->d_fsdata; 22ba1e563cSChandan Rajendra 23ba1e563cSChandan Rajendra return oe->lowerstack[0].layer->pseudo_dev; 24ba1e563cSChandan Rajendra } 25ba1e563cSChandan Rajendra 26e9be9d5eSMiklos Szeredi int ovl_setattr(struct dentry *dentry, struct iattr *attr) 27e9be9d5eSMiklos Szeredi { 28e9be9d5eSMiklos Szeredi int err; 29e9be9d5eSMiklos Szeredi struct dentry *upperdentry; 301175b6b8SVivek Goyal const struct cred *old_cred; 31e9be9d5eSMiklos Szeredi 32cf9a6784SMiklos Szeredi /* 33cf9a6784SMiklos Szeredi * Check for permissions before trying to copy-up. This is redundant 34cf9a6784SMiklos Szeredi * since it will be rechecked later by ->setattr() on upper dentry. But 35cf9a6784SMiklos Szeredi * without this, copy-up can be triggered by just about anybody. 36cf9a6784SMiklos Szeredi * 37cf9a6784SMiklos Szeredi * We don't initialize inode->size, which just means that 38cf9a6784SMiklos Szeredi * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not 39cf9a6784SMiklos Szeredi * check for a swapfile (which this won't be anyway). 40cf9a6784SMiklos Szeredi */ 4131051c85SJan Kara err = setattr_prepare(dentry, attr); 42cf9a6784SMiklos Szeredi if (err) 43cf9a6784SMiklos Szeredi return err; 44cf9a6784SMiklos Szeredi 45e9be9d5eSMiklos Szeredi err = ovl_want_write(dentry); 46e9be9d5eSMiklos Szeredi if (err) 47e9be9d5eSMiklos Szeredi goto out; 48e9be9d5eSMiklos Szeredi 49acff81ecSMiklos Szeredi err = ovl_copy_up(dentry); 50acff81ecSMiklos Szeredi if (!err) { 51e9be9d5eSMiklos Szeredi upperdentry = ovl_dentry_upper(dentry); 52acff81ecSMiklos Szeredi 53b99c2d91SMiklos Szeredi if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) 54b99c2d91SMiklos Szeredi attr->ia_valid &= ~ATTR_MODE; 55b99c2d91SMiklos Szeredi 565955102cSAl Viro inode_lock(upperdentry->d_inode); 571175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 58e9be9d5eSMiklos Szeredi err = notify_change(upperdentry, attr, NULL); 591175b6b8SVivek Goyal revert_creds(old_cred); 60b81de061SKonstantin Khlebnikov if (!err) 61b81de061SKonstantin Khlebnikov ovl_copyattr(upperdentry->d_inode, dentry->d_inode); 625955102cSAl Viro inode_unlock(upperdentry->d_inode); 63e9be9d5eSMiklos Szeredi } 64e9be9d5eSMiklos Szeredi ovl_drop_write(dentry); 65e9be9d5eSMiklos Szeredi out: 66e9be9d5eSMiklos Szeredi return err; 67e9be9d5eSMiklos Szeredi } 68e9be9d5eSMiklos Szeredi 695b712091SMiklos Szeredi int ovl_getattr(const struct path *path, struct kstat *stat, 70a528d35eSDavid Howells u32 request_mask, unsigned int flags) 71e9be9d5eSMiklos Szeredi { 72a528d35eSDavid Howells struct dentry *dentry = path->dentry; 7372b608f0SAmir Goldstein enum ovl_path_type type; 74e9be9d5eSMiklos Szeredi struct path realpath; 751175b6b8SVivek Goyal const struct cred *old_cred; 765b712091SMiklos Szeredi bool is_dir = S_ISDIR(dentry->d_inode->i_mode); 77a0c5ad30SAmir Goldstein bool samefs = ovl_same_sb(dentry->d_sb); 781175b6b8SVivek Goyal int err; 79e9be9d5eSMiklos Szeredi 8072b608f0SAmir Goldstein type = ovl_path_real(dentry, &realpath); 811175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 82a528d35eSDavid Howells err = vfs_getattr(&realpath, stat, request_mask, flags); 8372b608f0SAmir Goldstein if (err) 8472b608f0SAmir Goldstein goto out; 8572b608f0SAmir Goldstein 8672b608f0SAmir Goldstein /* 87a0c5ad30SAmir Goldstein * For non-dir or same fs, we use st_ino of the copy up origin, if we 88a0c5ad30SAmir Goldstein * know it. This guaranties constant st_dev/st_ino across copy up. 8972b608f0SAmir Goldstein * 9072b608f0SAmir Goldstein * If filesystem supports NFS export ops, this also guaranties 9172b608f0SAmir Goldstein * persistent st_ino across mount cycle. 9272b608f0SAmir Goldstein */ 93a0c5ad30SAmir Goldstein if (!is_dir || samefs) { 9472b608f0SAmir Goldstein if (OVL_TYPE_ORIGIN(type)) { 9572b608f0SAmir Goldstein struct kstat lowerstat; 965b712091SMiklos Szeredi u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0); 9772b608f0SAmir Goldstein 9872b608f0SAmir Goldstein ovl_path_lower(dentry, &realpath); 9972b608f0SAmir Goldstein err = vfs_getattr(&realpath, &lowerstat, 1005b712091SMiklos Szeredi lowermask, flags); 10172b608f0SAmir Goldstein if (err) 10272b608f0SAmir Goldstein goto out; 10372b608f0SAmir Goldstein 10472b608f0SAmir Goldstein /* 105359f392cSAmir Goldstein * Lower hardlinks may be broken on copy up to different 10672b608f0SAmir Goldstein * upper files, so we cannot use the lower origin st_ino 10772b608f0SAmir Goldstein * for those different files, even for the same fs case. 10886eaa130SAmir Goldstein * 10986eaa130SAmir Goldstein * Similarly, several redirected dirs can point to the 11086eaa130SAmir Goldstein * same dir on a lower layer. With the "verify_lower" 11186eaa130SAmir Goldstein * feature, we do not use the lower origin st_ino, if 11286eaa130SAmir Goldstein * we haven't verified that this redirect is unique. 11386eaa130SAmir Goldstein * 114359f392cSAmir Goldstein * With inodes index enabled, it is safe to use st_ino 11586eaa130SAmir Goldstein * of an indexed origin. The index validates that the 11686eaa130SAmir Goldstein * upper hardlink is not broken and that a redirected 11786eaa130SAmir Goldstein * dir is the only redirect to that origin. 11872b608f0SAmir Goldstein */ 11986eaa130SAmir Goldstein if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) || 12086eaa130SAmir Goldstein (!ovl_verify_lower(dentry->d_sb) && 12186eaa130SAmir Goldstein (is_dir || lowerstat.nlink == 1))) 12272b608f0SAmir Goldstein stat->ino = lowerstat.ino; 123a0c5ad30SAmir Goldstein 124a0c5ad30SAmir Goldstein if (samefs) 125a0c5ad30SAmir Goldstein WARN_ON_ONCE(stat->dev != lowerstat.dev); 126a0c5ad30SAmir Goldstein else 127a0c5ad30SAmir Goldstein stat->dev = ovl_get_pseudo_dev(dentry); 12872b608f0SAmir Goldstein } 129a0c5ad30SAmir Goldstein if (samefs) { 1305b712091SMiklos Szeredi /* 131a0c5ad30SAmir Goldstein * When all layers are on the same fs, all real inode 132a0c5ad30SAmir Goldstein * number are unique, so we use the overlay st_dev, 133a0c5ad30SAmir Goldstein * which is friendly to du -x. 134a0c5ad30SAmir Goldstein */ 135a0c5ad30SAmir Goldstein stat->dev = dentry->d_sb->s_dev; 136a0c5ad30SAmir Goldstein } else if (!OVL_TYPE_UPPER(type)) { 137a0c5ad30SAmir Goldstein /* 138a0c5ad30SAmir Goldstein * For non-samefs setup, to make sure that st_dev/st_ino 139a0c5ad30SAmir Goldstein * pair is unique across the system, we use a unique 140a0c5ad30SAmir Goldstein * anonymous st_dev for lower layer inode. 141a0c5ad30SAmir Goldstein */ 142a0c5ad30SAmir Goldstein stat->dev = ovl_get_pseudo_dev(dentry); 143a0c5ad30SAmir Goldstein } 144a0c5ad30SAmir Goldstein } else { 145a0c5ad30SAmir Goldstein /* 1465b712091SMiklos Szeredi * Always use the overlay st_dev for directories, so 'find 1475b712091SMiklos Szeredi * -xdev' will scan the entire overlay mount and won't cross the 1485b712091SMiklos Szeredi * overlay mount boundaries. 149a0c5ad30SAmir Goldstein * 150a0c5ad30SAmir Goldstein * If not all layers are on the same fs the pair {real st_ino; 151a0c5ad30SAmir Goldstein * overlay st_dev} is not unique, so use the non persistent 152a0c5ad30SAmir Goldstein * overlay st_ino for directories. 1535b712091SMiklos Szeredi */ 1545b712091SMiklos Szeredi stat->dev = dentry->d_sb->s_dev; 1555b712091SMiklos Szeredi stat->ino = dentry->d_inode->i_ino; 15672b608f0SAmir Goldstein } 1575b712091SMiklos Szeredi 1585b712091SMiklos Szeredi /* 1595b712091SMiklos Szeredi * It's probably not worth it to count subdirs to get the 1605b712091SMiklos Szeredi * correct link count. nlink=1 seems to pacify 'find' and 1615b712091SMiklos Szeredi * other utilities. 1625b712091SMiklos Szeredi */ 1635b712091SMiklos Szeredi if (is_dir && OVL_TYPE_MERGE(type)) 1645b712091SMiklos Szeredi stat->nlink = 1; 1655b712091SMiklos Szeredi 1665f8415d6SAmir Goldstein /* 1675f8415d6SAmir Goldstein * Return the overlay inode nlinks for indexed upper inodes. 1685f8415d6SAmir Goldstein * Overlay inode nlink counts the union of the upper hardlinks 1695f8415d6SAmir Goldstein * and non-covered lower hardlinks. It does not include the upper 1705f8415d6SAmir Goldstein * index hardlink. 1715f8415d6SAmir Goldstein */ 1725f8415d6SAmir Goldstein if (!is_dir && ovl_test_flag(OVL_INDEX, d_inode(dentry))) 1735f8415d6SAmir Goldstein stat->nlink = dentry->d_inode->i_nlink; 1745f8415d6SAmir Goldstein 17572b608f0SAmir Goldstein out: 1761175b6b8SVivek Goyal revert_creds(old_cred); 17772b608f0SAmir Goldstein 1781175b6b8SVivek Goyal return err; 179e9be9d5eSMiklos Szeredi } 180e9be9d5eSMiklos Szeredi 181e9be9d5eSMiklos Szeredi int ovl_permission(struct inode *inode, int mask) 182e9be9d5eSMiklos Szeredi { 18309d8b586SMiklos Szeredi struct inode *upperinode = ovl_inode_upper(inode); 18409d8b586SMiklos Szeredi struct inode *realinode = upperinode ?: ovl_inode_lower(inode); 185c0ca3d70SVivek Goyal const struct cred *old_cred; 186e9be9d5eSMiklos Szeredi int err; 187e9be9d5eSMiklos Szeredi 188e9be9d5eSMiklos Szeredi /* Careful in RCU walk mode */ 189e9be9d5eSMiklos Szeredi if (!realinode) { 190e9be9d5eSMiklos Szeredi WARN_ON(!(mask & MAY_NOT_BLOCK)); 191a999d7e1SMiklos Szeredi return -ECHILD; 192e9be9d5eSMiklos Szeredi } 193e9be9d5eSMiklos Szeredi 194c0ca3d70SVivek Goyal /* 195c0ca3d70SVivek Goyal * Check overlay inode with the creds of task and underlying inode 196c0ca3d70SVivek Goyal * with creds of mounter 197c0ca3d70SVivek Goyal */ 198c0ca3d70SVivek Goyal err = generic_permission(inode, mask); 199c0ca3d70SVivek Goyal if (err) 200c0ca3d70SVivek Goyal return err; 201c0ca3d70SVivek Goyal 202c0ca3d70SVivek Goyal old_cred = ovl_override_creds(inode->i_sb); 20309d8b586SMiklos Szeredi if (!upperinode && 20409d8b586SMiklos Szeredi !special_file(realinode->i_mode) && mask & MAY_WRITE) { 205754f8cb7SVivek Goyal mask &= ~(MAY_WRITE | MAY_APPEND); 206500cac3cSVivek Goyal /* Make sure mounter can read file for copy up later */ 207500cac3cSVivek Goyal mask |= MAY_READ; 208500cac3cSVivek Goyal } 2099c630ebeSMiklos Szeredi err = inode_permission(realinode, mask); 210c0ca3d70SVivek Goyal revert_creds(old_cred); 211c0ca3d70SVivek Goyal 212c0ca3d70SVivek Goyal return err; 213e9be9d5eSMiklos Szeredi } 214e9be9d5eSMiklos Szeredi 2156b255391SAl Viro static const char *ovl_get_link(struct dentry *dentry, 216fceef393SAl Viro struct inode *inode, 217fceef393SAl Viro struct delayed_call *done) 218e9be9d5eSMiklos Szeredi { 2191175b6b8SVivek Goyal const struct cred *old_cred; 2201175b6b8SVivek Goyal const char *p; 221e9be9d5eSMiklos Szeredi 2226b255391SAl Viro if (!dentry) 2236b255391SAl Viro return ERR_PTR(-ECHILD); 2246b255391SAl Viro 2251175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 2267764235bSMiklos Szeredi p = vfs_get_link(ovl_dentry_real(dentry), done); 2271175b6b8SVivek Goyal revert_creds(old_cred); 2281175b6b8SVivek Goyal return p; 229e9be9d5eSMiklos Szeredi } 230e9be9d5eSMiklos Szeredi 2310956254aSMiklos Szeredi bool ovl_is_private_xattr(const char *name) 232e9be9d5eSMiklos Szeredi { 233fe2b7595SAndreas Gruenbacher return strncmp(name, OVL_XATTR_PREFIX, 234fe2b7595SAndreas Gruenbacher sizeof(OVL_XATTR_PREFIX) - 1) == 0; 235e9be9d5eSMiklos Szeredi } 236e9be9d5eSMiklos Szeredi 2371d88f183SMiklos Szeredi int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 2381d88f183SMiklos Szeredi const void *value, size_t size, int flags) 239e9be9d5eSMiklos Szeredi { 240e9be9d5eSMiklos Szeredi int err; 2411d88f183SMiklos Szeredi struct dentry *upperdentry = ovl_i_dentry_upper(inode); 2421d88f183SMiklos Szeredi struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); 2431175b6b8SVivek Goyal const struct cred *old_cred; 244e9be9d5eSMiklos Szeredi 245e9be9d5eSMiklos Szeredi err = ovl_want_write(dentry); 246e9be9d5eSMiklos Szeredi if (err) 247e9be9d5eSMiklos Szeredi goto out; 248e9be9d5eSMiklos Szeredi 2491d88f183SMiklos Szeredi if (!value && !upperdentry) { 2501d88f183SMiklos Szeredi err = vfs_getxattr(realdentry, name, NULL, 0); 2510e585cccSAndreas Gruenbacher if (err < 0) 2520e585cccSAndreas Gruenbacher goto out_drop_write; 2530e585cccSAndreas Gruenbacher } 2540e585cccSAndreas Gruenbacher 2551d88f183SMiklos Szeredi if (!upperdentry) { 256e9be9d5eSMiklos Szeredi err = ovl_copy_up(dentry); 257e9be9d5eSMiklos Szeredi if (err) 258e9be9d5eSMiklos Szeredi goto out_drop_write; 259e9be9d5eSMiklos Szeredi 2601d88f183SMiklos Szeredi realdentry = ovl_dentry_upper(dentry); 2611d88f183SMiklos Szeredi } 2620e585cccSAndreas Gruenbacher 2631175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 2640e585cccSAndreas Gruenbacher if (value) 2651d88f183SMiklos Szeredi err = vfs_setxattr(realdentry, name, value, size, flags); 2660e585cccSAndreas Gruenbacher else { 2670e585cccSAndreas Gruenbacher WARN_ON(flags != XATTR_REPLACE); 2681d88f183SMiklos Szeredi err = vfs_removexattr(realdentry, name); 2690e585cccSAndreas Gruenbacher } 2701175b6b8SVivek Goyal revert_creds(old_cred); 271e9be9d5eSMiklos Szeredi 272e9be9d5eSMiklos Szeredi out_drop_write: 273e9be9d5eSMiklos Szeredi ovl_drop_write(dentry); 274e9be9d5eSMiklos Szeredi out: 275e9be9d5eSMiklos Szeredi return err; 276e9be9d5eSMiklos Szeredi } 277e9be9d5eSMiklos Szeredi 2781d88f183SMiklos Szeredi int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 2790eb45fc3SAndreas Gruenbacher void *value, size_t size) 280e9be9d5eSMiklos Szeredi { 2811175b6b8SVivek Goyal ssize_t res; 2821175b6b8SVivek Goyal const struct cred *old_cred; 2831d88f183SMiklos Szeredi struct dentry *realdentry = 2841d88f183SMiklos Szeredi ovl_i_dentry_upper(inode) ?: ovl_dentry_lower(dentry); 28552148463SMiklos Szeredi 2861175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 2871175b6b8SVivek Goyal res = vfs_getxattr(realdentry, name, value, size); 2881175b6b8SVivek Goyal revert_creds(old_cred); 2891175b6b8SVivek Goyal return res; 290e9be9d5eSMiklos Szeredi } 291e9be9d5eSMiklos Szeredi 292a082c6f6SMiklos Szeredi static bool ovl_can_list(const char *s) 293a082c6f6SMiklos Szeredi { 294a082c6f6SMiklos Szeredi /* List all non-trusted xatts */ 295a082c6f6SMiklos Szeredi if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) 296a082c6f6SMiklos Szeredi return true; 297a082c6f6SMiklos Szeredi 298a082c6f6SMiklos Szeredi /* Never list trusted.overlay, list other trusted for superuser only */ 299a082c6f6SMiklos Szeredi return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); 300a082c6f6SMiklos Szeredi } 301a082c6f6SMiklos Szeredi 302e9be9d5eSMiklos Szeredi ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) 303e9be9d5eSMiklos Szeredi { 304b581755bSMiklos Szeredi struct dentry *realdentry = ovl_dentry_real(dentry); 305e9be9d5eSMiklos Szeredi ssize_t res; 3067cb35119SMiklos Szeredi size_t len; 3077cb35119SMiklos Szeredi char *s; 3081175b6b8SVivek Goyal const struct cred *old_cred; 309e9be9d5eSMiklos Szeredi 3101175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 311b581755bSMiklos Szeredi res = vfs_listxattr(realdentry, list, size); 3121175b6b8SVivek Goyal revert_creds(old_cred); 313e9be9d5eSMiklos Szeredi if (res <= 0 || size == 0) 314e9be9d5eSMiklos Szeredi return res; 315e9be9d5eSMiklos Szeredi 316e9be9d5eSMiklos Szeredi /* filter out private xattrs */ 3177cb35119SMiklos Szeredi for (s = list, len = res; len;) { 3187cb35119SMiklos Szeredi size_t slen = strnlen(s, len) + 1; 319e9be9d5eSMiklos Szeredi 3207cb35119SMiklos Szeredi /* underlying fs providing us with an broken xattr list? */ 3217cb35119SMiklos Szeredi if (WARN_ON(slen > len)) 3227cb35119SMiklos Szeredi return -EIO; 323e9be9d5eSMiklos Szeredi 3247cb35119SMiklos Szeredi len -= slen; 325a082c6f6SMiklos Szeredi if (!ovl_can_list(s)) { 326e9be9d5eSMiklos Szeredi res -= slen; 3277cb35119SMiklos Szeredi memmove(s, s + slen, len); 328e9be9d5eSMiklos Szeredi } else { 3297cb35119SMiklos Szeredi s += slen; 330e9be9d5eSMiklos Szeredi } 331e9be9d5eSMiklos Szeredi } 332e9be9d5eSMiklos Szeredi 333e9be9d5eSMiklos Szeredi return res; 334e9be9d5eSMiklos Szeredi } 335e9be9d5eSMiklos Szeredi 33639a25b2bSVivek Goyal struct posix_acl *ovl_get_acl(struct inode *inode, int type) 33739a25b2bSVivek Goyal { 33809d8b586SMiklos Szeredi struct inode *realinode = ovl_inode_real(inode); 3391175b6b8SVivek Goyal const struct cred *old_cred; 3401175b6b8SVivek Goyal struct posix_acl *acl; 34139a25b2bSVivek Goyal 3425201dc44SMiklos Szeredi if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode)) 34339a25b2bSVivek Goyal return NULL; 34439a25b2bSVivek Goyal 3451175b6b8SVivek Goyal old_cred = ovl_override_creds(inode->i_sb); 3465201dc44SMiklos Szeredi acl = get_acl(realinode, type); 3471175b6b8SVivek Goyal revert_creds(old_cred); 3481175b6b8SVivek Goyal 3491175b6b8SVivek Goyal return acl; 35039a25b2bSVivek Goyal } 35139a25b2bSVivek Goyal 35259be0971SAmir Goldstein static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) 353e9be9d5eSMiklos Szeredi { 354aa3ff3c1SAmir Goldstein /* Copy up of disconnected dentry does not set upper alias */ 35559be0971SAmir Goldstein if (ovl_dentry_upper(dentry) && 356aa3ff3c1SAmir Goldstein (ovl_dentry_has_upper_alias(dentry) || 357aa3ff3c1SAmir Goldstein (dentry->d_flags & DCACHE_DISCONNECTED))) 358e9be9d5eSMiklos Szeredi return false; 359e9be9d5eSMiklos Szeredi 36059be0971SAmir Goldstein if (special_file(d_inode(dentry)->i_mode)) 361e9be9d5eSMiklos Szeredi return false; 362e9be9d5eSMiklos Szeredi 363e9be9d5eSMiklos Szeredi if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC)) 364e9be9d5eSMiklos Szeredi return false; 365e9be9d5eSMiklos Szeredi 366e9be9d5eSMiklos Szeredi return true; 367e9be9d5eSMiklos Szeredi } 368e9be9d5eSMiklos Szeredi 3692d902671SMiklos Szeredi int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) 370e9be9d5eSMiklos Szeredi { 3712d902671SMiklos Szeredi int err = 0; 372e9be9d5eSMiklos Szeredi 37359be0971SAmir Goldstein if (ovl_open_need_copy_up(dentry, file_flags)) { 374e9be9d5eSMiklos Szeredi err = ovl_want_write(dentry); 3752d902671SMiklos Szeredi if (!err) { 3769aba6521SAmir Goldstein err = ovl_copy_up_flags(dentry, file_flags); 377f25801eeSDavid Howells ovl_drop_write(dentry); 3782d902671SMiklos Szeredi } 379e9be9d5eSMiklos Szeredi } 380e9be9d5eSMiklos Szeredi 3812d902671SMiklos Szeredi return err; 382e9be9d5eSMiklos Szeredi } 383e9be9d5eSMiklos Szeredi 384d719e8f2SMiklos Szeredi int ovl_update_time(struct inode *inode, struct timespec *ts, int flags) 385d719e8f2SMiklos Szeredi { 386d719e8f2SMiklos Szeredi struct dentry *alias; 387d719e8f2SMiklos Szeredi struct path upperpath; 388d719e8f2SMiklos Szeredi 389d719e8f2SMiklos Szeredi if (!(flags & S_ATIME)) 390d719e8f2SMiklos Szeredi return 0; 391d719e8f2SMiklos Szeredi 392d719e8f2SMiklos Szeredi alias = d_find_any_alias(inode); 393d719e8f2SMiklos Szeredi if (!alias) 394d719e8f2SMiklos Szeredi return 0; 395d719e8f2SMiklos Szeredi 396d719e8f2SMiklos Szeredi ovl_path_upper(alias, &upperpath); 397d719e8f2SMiklos Szeredi if (upperpath.dentry) { 398d719e8f2SMiklos Szeredi touch_atime(&upperpath); 399d719e8f2SMiklos Szeredi inode->i_atime = d_inode(upperpath.dentry)->i_atime; 400d719e8f2SMiklos Szeredi } 401d719e8f2SMiklos Szeredi 402d719e8f2SMiklos Szeredi dput(alias); 403d719e8f2SMiklos Szeredi 404d719e8f2SMiklos Szeredi return 0; 405d719e8f2SMiklos Szeredi } 406d719e8f2SMiklos Szeredi 407e9be9d5eSMiklos Szeredi static const struct inode_operations ovl_file_inode_operations = { 408e9be9d5eSMiklos Szeredi .setattr = ovl_setattr, 409e9be9d5eSMiklos Szeredi .permission = ovl_permission, 410e9be9d5eSMiklos Szeredi .getattr = ovl_getattr, 411e9be9d5eSMiklos Szeredi .listxattr = ovl_listxattr, 41239a25b2bSVivek Goyal .get_acl = ovl_get_acl, 413d719e8f2SMiklos Szeredi .update_time = ovl_update_time, 414e9be9d5eSMiklos Szeredi }; 415e9be9d5eSMiklos Szeredi 416e9be9d5eSMiklos Szeredi static const struct inode_operations ovl_symlink_inode_operations = { 417e9be9d5eSMiklos Szeredi .setattr = ovl_setattr, 4186b255391SAl Viro .get_link = ovl_get_link, 419e9be9d5eSMiklos Szeredi .getattr = ovl_getattr, 420e9be9d5eSMiklos Szeredi .listxattr = ovl_listxattr, 421d719e8f2SMiklos Szeredi .update_time = ovl_update_time, 422e9be9d5eSMiklos Szeredi }; 423e9be9d5eSMiklos Szeredi 424b1eaa950SAmir Goldstein /* 425b1eaa950SAmir Goldstein * It is possible to stack overlayfs instance on top of another 426b1eaa950SAmir Goldstein * overlayfs instance as lower layer. We need to annonate the 427b1eaa950SAmir Goldstein * stackable i_mutex locks according to stack level of the super 428b1eaa950SAmir Goldstein * block instance. An overlayfs instance can never be in stack 429b1eaa950SAmir Goldstein * depth 0 (there is always a real fs below it). An overlayfs 430b1eaa950SAmir Goldstein * inode lock will use the lockdep annotaion ovl_i_mutex_key[depth]. 431b1eaa950SAmir Goldstein * 432b1eaa950SAmir Goldstein * For example, here is a snip from /proc/lockdep_chains after 433b1eaa950SAmir Goldstein * dir_iterate of nested overlayfs: 434b1eaa950SAmir Goldstein * 435b1eaa950SAmir Goldstein * [...] &ovl_i_mutex_dir_key[depth] (stack_depth=2) 436b1eaa950SAmir Goldstein * [...] &ovl_i_mutex_dir_key[depth]#2 (stack_depth=1) 437b1eaa950SAmir Goldstein * [...] &type->i_mutex_dir_key (stack_depth=0) 438b1eaa950SAmir Goldstein */ 439b1eaa950SAmir Goldstein #define OVL_MAX_NESTING FILESYSTEM_MAX_STACK_DEPTH 440b1eaa950SAmir Goldstein 441b1eaa950SAmir Goldstein static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode) 442b1eaa950SAmir Goldstein { 443b1eaa950SAmir Goldstein #ifdef CONFIG_LOCKDEP 444b1eaa950SAmir Goldstein static struct lock_class_key ovl_i_mutex_key[OVL_MAX_NESTING]; 445b1eaa950SAmir Goldstein static struct lock_class_key ovl_i_mutex_dir_key[OVL_MAX_NESTING]; 4464eae06deSAmir Goldstein static struct lock_class_key ovl_i_lock_key[OVL_MAX_NESTING]; 447b1eaa950SAmir Goldstein 448b1eaa950SAmir Goldstein int depth = inode->i_sb->s_stack_depth - 1; 449b1eaa950SAmir Goldstein 450b1eaa950SAmir Goldstein if (WARN_ON_ONCE(depth < 0 || depth >= OVL_MAX_NESTING)) 451b1eaa950SAmir Goldstein depth = 0; 452b1eaa950SAmir Goldstein 453b1eaa950SAmir Goldstein if (S_ISDIR(inode->i_mode)) 454b1eaa950SAmir Goldstein lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_dir_key[depth]); 455b1eaa950SAmir Goldstein else 456b1eaa950SAmir Goldstein lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_key[depth]); 4574eae06deSAmir Goldstein 4584eae06deSAmir Goldstein lockdep_set_class(&OVL_I(inode)->lock, &ovl_i_lock_key[depth]); 459b1eaa950SAmir Goldstein #endif 460b1eaa950SAmir Goldstein } 461b1eaa950SAmir Goldstein 462*695b46e7SAmir Goldstein static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev, 463*695b46e7SAmir Goldstein unsigned long ino) 464e9be9d5eSMiklos Szeredi { 465*695b46e7SAmir Goldstein /* 466*695b46e7SAmir Goldstein * When NFS export is enabled and d_ino is consistent with st_ino 467*695b46e7SAmir Goldstein * (samefs), set the same value to i_ino, because nfsd readdirplus 468*695b46e7SAmir Goldstein * compares d_ino values to i_ino values of child entries. When called 469*695b46e7SAmir Goldstein * from ovl_new_inode(), ino arg is 0, so i_ino will be updated to real 470*695b46e7SAmir Goldstein * upper inode i_ino on ovl_inode_init() or ovl_inode_update(). 471*695b46e7SAmir Goldstein */ 472*695b46e7SAmir Goldstein if (inode->i_sb->s_export_op && ovl_same_sb(inode->i_sb)) 473*695b46e7SAmir Goldstein inode->i_ino = ino; 474*695b46e7SAmir Goldstein else 475e9be9d5eSMiklos Szeredi inode->i_ino = get_next_ino(); 476e9be9d5eSMiklos Szeredi inode->i_mode = mode; 477d719e8f2SMiklos Szeredi inode->i_flags |= S_NOCMTIME; 4782a3a2a3fSMiklos Szeredi #ifdef CONFIG_FS_POSIX_ACL 4792a3a2a3fSMiklos Szeredi inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; 4802a3a2a3fSMiklos Szeredi #endif 481e9be9d5eSMiklos Szeredi 482b1eaa950SAmir Goldstein ovl_lockdep_annotate_inode_mutex_key(inode); 483b1eaa950SAmir Goldstein 484ca4c8a3aSMiklos Szeredi switch (mode & S_IFMT) { 485ca4c8a3aSMiklos Szeredi case S_IFREG: 486ca4c8a3aSMiklos Szeredi inode->i_op = &ovl_file_inode_operations; 487ca4c8a3aSMiklos Szeredi break; 488ca4c8a3aSMiklos Szeredi 489e9be9d5eSMiklos Szeredi case S_IFDIR: 490e9be9d5eSMiklos Szeredi inode->i_op = &ovl_dir_inode_operations; 491e9be9d5eSMiklos Szeredi inode->i_fop = &ovl_dir_operations; 492e9be9d5eSMiklos Szeredi break; 493e9be9d5eSMiklos Szeredi 494e9be9d5eSMiklos Szeredi case S_IFLNK: 495e9be9d5eSMiklos Szeredi inode->i_op = &ovl_symlink_inode_operations; 496e9be9d5eSMiklos Szeredi break; 497e9be9d5eSMiklos Szeredi 49851f7e52dSMiklos Szeredi default: 499e9be9d5eSMiklos Szeredi inode->i_op = &ovl_file_inode_operations; 500ca4c8a3aSMiklos Szeredi init_special_inode(inode, mode, rdev); 501e9be9d5eSMiklos Szeredi break; 50251f7e52dSMiklos Szeredi } 50351f7e52dSMiklos Szeredi } 504e9be9d5eSMiklos Szeredi 5055f8415d6SAmir Goldstein /* 5065f8415d6SAmir Goldstein * With inodes index enabled, an overlay inode nlink counts the union of upper 5075f8415d6SAmir Goldstein * hardlinks and non-covered lower hardlinks. During the lifetime of a non-pure 5085f8415d6SAmir Goldstein * upper inode, the following nlink modifying operations can happen: 5095f8415d6SAmir Goldstein * 5105f8415d6SAmir Goldstein * 1. Lower hardlink copy up 5115f8415d6SAmir Goldstein * 2. Upper hardlink created, unlinked or renamed over 5125f8415d6SAmir Goldstein * 3. Lower hardlink whiteout or renamed over 5135f8415d6SAmir Goldstein * 5145f8415d6SAmir Goldstein * For the first, copy up case, the union nlink does not change, whether the 5155f8415d6SAmir Goldstein * operation succeeds or fails, but the upper inode nlink may change. 5165f8415d6SAmir Goldstein * Therefore, before copy up, we store the union nlink value relative to the 5175f8415d6SAmir Goldstein * lower inode nlink in the index inode xattr trusted.overlay.nlink. 5185f8415d6SAmir Goldstein * 5195f8415d6SAmir Goldstein * For the second, upper hardlink case, the union nlink should be incremented 5205f8415d6SAmir Goldstein * or decremented IFF the operation succeeds, aligned with nlink change of the 5215f8415d6SAmir Goldstein * upper inode. Therefore, before link/unlink/rename, we store the union nlink 5225f8415d6SAmir Goldstein * value relative to the upper inode nlink in the index inode. 5235f8415d6SAmir Goldstein * 5245f8415d6SAmir Goldstein * For the last, lower cover up case, we simplify things by preceding the 5255f8415d6SAmir Goldstein * whiteout or cover up with copy up. This makes sure that there is an index 5265f8415d6SAmir Goldstein * upper inode where the nlink xattr can be stored before the copied up upper 5275f8415d6SAmir Goldstein * entry is unlink. 5285f8415d6SAmir Goldstein */ 5295f8415d6SAmir Goldstein #define OVL_NLINK_ADD_UPPER (1 << 0) 5305f8415d6SAmir Goldstein 5315f8415d6SAmir Goldstein /* 5325f8415d6SAmir Goldstein * On-disk format for indexed nlink: 5335f8415d6SAmir Goldstein * 5345f8415d6SAmir Goldstein * nlink relative to the upper inode - "U[+-]NUM" 5355f8415d6SAmir Goldstein * nlink relative to the lower inode - "L[+-]NUM" 5365f8415d6SAmir Goldstein */ 5375f8415d6SAmir Goldstein 5385f8415d6SAmir Goldstein static int ovl_set_nlink_common(struct dentry *dentry, 5395f8415d6SAmir Goldstein struct dentry *realdentry, const char *format) 5405f8415d6SAmir Goldstein { 5415f8415d6SAmir Goldstein struct inode *inode = d_inode(dentry); 5425f8415d6SAmir Goldstein struct inode *realinode = d_inode(realdentry); 5435f8415d6SAmir Goldstein char buf[13]; 5445f8415d6SAmir Goldstein int len; 5455f8415d6SAmir Goldstein 5465f8415d6SAmir Goldstein len = snprintf(buf, sizeof(buf), format, 5475f8415d6SAmir Goldstein (int) (inode->i_nlink - realinode->i_nlink)); 5485f8415d6SAmir Goldstein 5496787341aSMiklos Szeredi if (WARN_ON(len >= sizeof(buf))) 5506787341aSMiklos Szeredi return -EIO; 5516787341aSMiklos Szeredi 5525f8415d6SAmir Goldstein return ovl_do_setxattr(ovl_dentry_upper(dentry), 5535f8415d6SAmir Goldstein OVL_XATTR_NLINK, buf, len, 0); 5545f8415d6SAmir Goldstein } 5555f8415d6SAmir Goldstein 5565f8415d6SAmir Goldstein int ovl_set_nlink_upper(struct dentry *dentry) 5575f8415d6SAmir Goldstein { 5585f8415d6SAmir Goldstein return ovl_set_nlink_common(dentry, ovl_dentry_upper(dentry), "U%+i"); 5595f8415d6SAmir Goldstein } 5605f8415d6SAmir Goldstein 5615f8415d6SAmir Goldstein int ovl_set_nlink_lower(struct dentry *dentry) 5625f8415d6SAmir Goldstein { 5635f8415d6SAmir Goldstein return ovl_set_nlink_common(dentry, ovl_dentry_lower(dentry), "L%+i"); 5645f8415d6SAmir Goldstein } 5655f8415d6SAmir Goldstein 566caf70cb2SAmir Goldstein unsigned int ovl_get_nlink(struct dentry *lowerdentry, 5675f8415d6SAmir Goldstein struct dentry *upperdentry, 5685f8415d6SAmir Goldstein unsigned int fallback) 5695f8415d6SAmir Goldstein { 5705f8415d6SAmir Goldstein int nlink_diff; 5715f8415d6SAmir Goldstein int nlink; 5725f8415d6SAmir Goldstein char buf[13]; 5735f8415d6SAmir Goldstein int err; 5745f8415d6SAmir Goldstein 5755f8415d6SAmir Goldstein if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1) 5765f8415d6SAmir Goldstein return fallback; 5775f8415d6SAmir Goldstein 5785f8415d6SAmir Goldstein err = vfs_getxattr(upperdentry, OVL_XATTR_NLINK, &buf, sizeof(buf) - 1); 5795f8415d6SAmir Goldstein if (err < 0) 5805f8415d6SAmir Goldstein goto fail; 5815f8415d6SAmir Goldstein 5825f8415d6SAmir Goldstein buf[err] = '\0'; 5835f8415d6SAmir Goldstein if ((buf[0] != 'L' && buf[0] != 'U') || 5845f8415d6SAmir Goldstein (buf[1] != '+' && buf[1] != '-')) 5855f8415d6SAmir Goldstein goto fail; 5865f8415d6SAmir Goldstein 5875f8415d6SAmir Goldstein err = kstrtoint(buf + 1, 10, &nlink_diff); 5885f8415d6SAmir Goldstein if (err < 0) 5895f8415d6SAmir Goldstein goto fail; 5905f8415d6SAmir Goldstein 5915f8415d6SAmir Goldstein nlink = d_inode(buf[0] == 'L' ? lowerdentry : upperdentry)->i_nlink; 5925f8415d6SAmir Goldstein nlink += nlink_diff; 5935f8415d6SAmir Goldstein 5945f8415d6SAmir Goldstein if (nlink <= 0) 5955f8415d6SAmir Goldstein goto fail; 5965f8415d6SAmir Goldstein 5975f8415d6SAmir Goldstein return nlink; 5985f8415d6SAmir Goldstein 5995f8415d6SAmir Goldstein fail: 6005f8415d6SAmir Goldstein pr_warn_ratelimited("overlayfs: failed to get index nlink (%pd2, err=%i)\n", 6015f8415d6SAmir Goldstein upperdentry, err); 6025f8415d6SAmir Goldstein return fallback; 6035f8415d6SAmir Goldstein } 6045f8415d6SAmir Goldstein 605ca4c8a3aSMiklos Szeredi struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev) 60651f7e52dSMiklos Szeredi { 60751f7e52dSMiklos Szeredi struct inode *inode; 60851f7e52dSMiklos Szeredi 60951f7e52dSMiklos Szeredi inode = new_inode(sb); 61051f7e52dSMiklos Szeredi if (inode) 611*695b46e7SAmir Goldstein ovl_fill_inode(inode, mode, rdev, 0); 61251f7e52dSMiklos Szeredi 61351f7e52dSMiklos Szeredi return inode; 61451f7e52dSMiklos Szeredi } 61551f7e52dSMiklos Szeredi 61651f7e52dSMiklos Szeredi static int ovl_inode_test(struct inode *inode, void *data) 61751f7e52dSMiklos Szeredi { 61825b7713aSMiklos Szeredi return inode->i_private == data; 61951f7e52dSMiklos Szeredi } 62051f7e52dSMiklos Szeredi 62151f7e52dSMiklos Szeredi static int ovl_inode_set(struct inode *inode, void *data) 62251f7e52dSMiklos Szeredi { 62325b7713aSMiklos Szeredi inode->i_private = data; 62451f7e52dSMiklos Szeredi return 0; 62551f7e52dSMiklos Szeredi } 62651f7e52dSMiklos Szeredi 627b9ac5c27SMiklos Szeredi static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry, 6284b91c30aSAmir Goldstein struct dentry *upperdentry, bool strict) 629b9ac5c27SMiklos Szeredi { 6304b91c30aSAmir Goldstein /* 6314b91c30aSAmir Goldstein * For directories, @strict verify from lookup path performs consistency 6324b91c30aSAmir Goldstein * checks, so NULL lower/upper in dentry must match NULL lower/upper in 6334b91c30aSAmir Goldstein * inode. Non @strict verify from NFS handle decode path passes NULL for 6344b91c30aSAmir Goldstein * 'unknown' lower/upper. 6354b91c30aSAmir Goldstein */ 6364b91c30aSAmir Goldstein if (S_ISDIR(inode->i_mode) && strict) { 63731747edaSAmir Goldstein /* Real lower dir moved to upper layer under us? */ 63831747edaSAmir Goldstein if (!lowerdentry && ovl_inode_lower(inode)) 63931747edaSAmir Goldstein return false; 64031747edaSAmir Goldstein 64131747edaSAmir Goldstein /* Lookup of an uncovered redirect origin? */ 64231747edaSAmir Goldstein if (!upperdentry && ovl_inode_upper(inode)) 64331747edaSAmir Goldstein return false; 64431747edaSAmir Goldstein } 64531747edaSAmir Goldstein 646939ae4efSAmir Goldstein /* 647939ae4efSAmir Goldstein * Allow non-NULL lower inode in ovl_inode even if lowerdentry is NULL. 648939ae4efSAmir Goldstein * This happens when finding a copied up overlay inode for a renamed 649939ae4efSAmir Goldstein * or hardlinked overlay dentry and lower dentry cannot be followed 650939ae4efSAmir Goldstein * by origin because lower fs does not support file handles. 651939ae4efSAmir Goldstein */ 652939ae4efSAmir Goldstein if (lowerdentry && ovl_inode_lower(inode) != d_inode(lowerdentry)) 653b9ac5c27SMiklos Szeredi return false; 654b9ac5c27SMiklos Szeredi 655b9ac5c27SMiklos Szeredi /* 656b9ac5c27SMiklos Szeredi * Allow non-NULL __upperdentry in inode even if upperdentry is NULL. 657b9ac5c27SMiklos Szeredi * This happens when finding a lower alias for a copied up hard link. 658b9ac5c27SMiklos Szeredi */ 659b9ac5c27SMiklos Szeredi if (upperdentry && ovl_inode_upper(inode) != d_inode(upperdentry)) 660b9ac5c27SMiklos Szeredi return false; 661b9ac5c27SMiklos Szeredi 662b9ac5c27SMiklos Szeredi return true; 663b9ac5c27SMiklos Szeredi } 664b9ac5c27SMiklos Szeredi 6654b91c30aSAmir Goldstein struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 6664b91c30aSAmir Goldstein bool is_upper) 6679436a1a3SAmir Goldstein { 6684b91c30aSAmir Goldstein struct inode *inode, *key = d_inode(real); 6699436a1a3SAmir Goldstein 6709436a1a3SAmir Goldstein inode = ilookup5(sb, (unsigned long) key, ovl_inode_test, key); 6719436a1a3SAmir Goldstein if (!inode) 6729436a1a3SAmir Goldstein return NULL; 6739436a1a3SAmir Goldstein 6744b91c30aSAmir Goldstein if (!ovl_verify_inode(inode, is_upper ? NULL : real, 6754b91c30aSAmir Goldstein is_upper ? real : NULL, false)) { 6769436a1a3SAmir Goldstein iput(inode); 6779436a1a3SAmir Goldstein return ERR_PTR(-ESTALE); 6789436a1a3SAmir Goldstein } 6799436a1a3SAmir Goldstein 6809436a1a3SAmir Goldstein return inode; 6819436a1a3SAmir Goldstein } 6829436a1a3SAmir Goldstein 683764baba8SAmir Goldstein /* 684764baba8SAmir Goldstein * Does overlay inode need to be hashed by lower inode? 685764baba8SAmir Goldstein */ 686764baba8SAmir Goldstein static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper, 687764baba8SAmir Goldstein struct dentry *lower, struct dentry *index) 688764baba8SAmir Goldstein { 689764baba8SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 690764baba8SAmir Goldstein 691764baba8SAmir Goldstein /* No, if pure upper */ 692764baba8SAmir Goldstein if (!lower) 693764baba8SAmir Goldstein return false; 694764baba8SAmir Goldstein 695764baba8SAmir Goldstein /* Yes, if already indexed */ 696764baba8SAmir Goldstein if (index) 697764baba8SAmir Goldstein return true; 698764baba8SAmir Goldstein 699764baba8SAmir Goldstein /* Yes, if won't be copied up */ 700764baba8SAmir Goldstein if (!ofs->upper_mnt) 701764baba8SAmir Goldstein return true; 702764baba8SAmir Goldstein 703764baba8SAmir Goldstein /* No, if lower hardlink is or will be broken on copy up */ 704764baba8SAmir Goldstein if ((upper || !ovl_indexdir(sb)) && 705764baba8SAmir Goldstein !d_is_dir(lower) && d_inode(lower)->i_nlink > 1) 706764baba8SAmir Goldstein return false; 707764baba8SAmir Goldstein 708764baba8SAmir Goldstein /* No, if non-indexed upper with NFS export */ 709764baba8SAmir Goldstein if (sb->s_export_op && upper) 710764baba8SAmir Goldstein return false; 711764baba8SAmir Goldstein 712764baba8SAmir Goldstein /* Otherwise, hash by lower inode for fsnotify */ 713764baba8SAmir Goldstein return true; 714764baba8SAmir Goldstein } 715764baba8SAmir Goldstein 7160aceb53eSAmir Goldstein struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, 7170aceb53eSAmir Goldstein struct dentry *lowerdentry, struct dentry *index, 7180aceb53eSAmir Goldstein unsigned int numlower) 71951f7e52dSMiklos Szeredi { 72009d8b586SMiklos Szeredi struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL; 72151f7e52dSMiklos Szeredi struct inode *inode; 722764baba8SAmir Goldstein bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index); 72331747edaSAmir Goldstein bool is_dir; 724*695b46e7SAmir Goldstein unsigned long ino = 0; 7256eaf0111SAmir Goldstein 72609d8b586SMiklos Szeredi if (!realinode) 72709d8b586SMiklos Szeredi realinode = d_inode(lowerdentry); 72809d8b586SMiklos Szeredi 7296eaf0111SAmir Goldstein /* 730764baba8SAmir Goldstein * Copy up origin (lower) may exist for non-indexed upper, but we must 731764baba8SAmir Goldstein * not use lower as hash key if this is a broken hardlink. 7326eaf0111SAmir Goldstein */ 73331747edaSAmir Goldstein is_dir = S_ISDIR(realinode->i_mode); 734764baba8SAmir Goldstein if (upperdentry || bylower) { 735764baba8SAmir Goldstein struct inode *key = d_inode(bylower ? lowerdentry : 736764baba8SAmir Goldstein upperdentry); 73731747edaSAmir Goldstein unsigned int nlink = is_dir ? 1 : realinode->i_nlink; 738b9ac5c27SMiklos Szeredi 7390aceb53eSAmir Goldstein inode = iget5_locked(sb, (unsigned long) key, 740b9ac5c27SMiklos Szeredi ovl_inode_test, ovl_inode_set, key); 74109d8b586SMiklos Szeredi if (!inode) 742b9ac5c27SMiklos Szeredi goto out_nomem; 74309d8b586SMiklos Szeredi if (!(inode->i_state & I_NEW)) { 744b9ac5c27SMiklos Szeredi /* 745b9ac5c27SMiklos Szeredi * Verify that the underlying files stored in the inode 746b9ac5c27SMiklos Szeredi * match those in the dentry. 747b9ac5c27SMiklos Szeredi */ 7484b91c30aSAmir Goldstein if (!ovl_verify_inode(inode, lowerdentry, upperdentry, 7494b91c30aSAmir Goldstein true)) { 750b9ac5c27SMiklos Szeredi iput(inode); 751b9ac5c27SMiklos Szeredi inode = ERR_PTR(-ESTALE); 752b9ac5c27SMiklos Szeredi goto out; 753b9ac5c27SMiklos Szeredi } 754b9ac5c27SMiklos Szeredi 75509d8b586SMiklos Szeredi dput(upperdentry); 75609d8b586SMiklos Szeredi goto out; 75709d8b586SMiklos Szeredi } 758e9be9d5eSMiklos Szeredi 75931747edaSAmir Goldstein /* Recalculate nlink for non-dir due to indexing */ 76031747edaSAmir Goldstein if (!is_dir) 76131747edaSAmir Goldstein nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink); 7625f8415d6SAmir Goldstein set_nlink(inode, nlink); 763*695b46e7SAmir Goldstein ino = key->i_ino; 764e6d2ebddSMiklos Szeredi } else { 765764baba8SAmir Goldstein /* Lower hardlink that will be broken on copy up */ 7660aceb53eSAmir Goldstein inode = new_inode(sb); 767e6d2ebddSMiklos Szeredi if (!inode) 768b9ac5c27SMiklos Szeredi goto out_nomem; 769e6d2ebddSMiklos Szeredi } 770*695b46e7SAmir Goldstein ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino); 77109d8b586SMiklos Szeredi ovl_inode_init(inode, upperdentry, lowerdentry); 77213c72075SMiklos Szeredi 77313c72075SMiklos Szeredi if (upperdentry && ovl_is_impuredir(upperdentry)) 77413c72075SMiklos Szeredi ovl_set_flag(OVL_IMPURE, inode); 77513c72075SMiklos Szeredi 776b79e05aaSAmir Goldstein /* Check for non-merge dir that may have whiteouts */ 77731747edaSAmir Goldstein if (is_dir) { 7780aceb53eSAmir Goldstein if (((upperdentry && lowerdentry) || numlower > 1) || 779b79e05aaSAmir Goldstein ovl_check_origin_xattr(upperdentry ?: lowerdentry)) { 780b79e05aaSAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, inode); 781b79e05aaSAmir Goldstein } 782b79e05aaSAmir Goldstein } 783b79e05aaSAmir Goldstein 784e6d2ebddSMiklos Szeredi if (inode->i_state & I_NEW) 785e6d2ebddSMiklos Szeredi unlock_new_inode(inode); 786e6d2ebddSMiklos Szeredi out: 787e9be9d5eSMiklos Szeredi return inode; 788b9ac5c27SMiklos Szeredi 789b9ac5c27SMiklos Szeredi out_nomem: 790b9ac5c27SMiklos Szeredi inode = ERR_PTR(-ENOMEM); 791b9ac5c27SMiklos Szeredi goto out; 792e9be9d5eSMiklos Szeredi } 793