1bbb1e54dSMiklos Szeredi /* 2bbb1e54dSMiklos Szeredi * Copyright (C) 2011 Novell Inc. 3bbb1e54dSMiklos Szeredi * Copyright (C) 2016 Red Hat, Inc. 4bbb1e54dSMiklos Szeredi * 5bbb1e54dSMiklos Szeredi * This program is free software; you can redistribute it and/or modify it 6bbb1e54dSMiklos Szeredi * under the terms of the GNU General Public License version 2 as published by 7bbb1e54dSMiklos Szeredi * the Free Software Foundation. 8bbb1e54dSMiklos Szeredi */ 9bbb1e54dSMiklos Szeredi 10bbb1e54dSMiklos Szeredi #include <linux/fs.h> 11bbb1e54dSMiklos Szeredi #include <linux/mount.h> 12bbb1e54dSMiklos Szeredi #include <linux/slab.h> 135b825c3aSIngo Molnar #include <linux/cred.h> 14bbb1e54dSMiklos Szeredi #include <linux/xattr.h> 1502bcd157SAmir Goldstein #include <linux/exportfs.h> 1602bcd157SAmir Goldstein #include <linux/uuid.h> 17caf70cb2SAmir Goldstein #include <linux/namei.h> 18caf70cb2SAmir Goldstein #include <linux/ratelimit.h> 19bbb1e54dSMiklos Szeredi #include "overlayfs.h" 20bbb1e54dSMiklos Szeredi 21bbb1e54dSMiklos Szeredi int ovl_want_write(struct dentry *dentry) 22bbb1e54dSMiklos Szeredi { 23bbb1e54dSMiklos Szeredi struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 24bbb1e54dSMiklos Szeredi return mnt_want_write(ofs->upper_mnt); 25bbb1e54dSMiklos Szeredi } 26bbb1e54dSMiklos Szeredi 27bbb1e54dSMiklos Szeredi void ovl_drop_write(struct dentry *dentry) 28bbb1e54dSMiklos Szeredi { 29bbb1e54dSMiklos Szeredi struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 30bbb1e54dSMiklos Szeredi mnt_drop_write(ofs->upper_mnt); 31bbb1e54dSMiklos Szeredi } 32bbb1e54dSMiklos Szeredi 33bbb1e54dSMiklos Szeredi struct dentry *ovl_workdir(struct dentry *dentry) 34bbb1e54dSMiklos Szeredi { 35bbb1e54dSMiklos Szeredi struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 36bbb1e54dSMiklos Szeredi return ofs->workdir; 37bbb1e54dSMiklos Szeredi } 38bbb1e54dSMiklos Szeredi 39bbb1e54dSMiklos Szeredi const struct cred *ovl_override_creds(struct super_block *sb) 40bbb1e54dSMiklos Szeredi { 41bbb1e54dSMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 42bbb1e54dSMiklos Szeredi 43bbb1e54dSMiklos Szeredi return override_creds(ofs->creator_cred); 44bbb1e54dSMiklos Szeredi } 45bbb1e54dSMiklos Szeredi 467bcd74b9SAmir Goldstein struct super_block *ovl_same_sb(struct super_block *sb) 477bcd74b9SAmir Goldstein { 487bcd74b9SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 497bcd74b9SAmir Goldstein 505148626bSAmir Goldstein if (!ofs->numlowerfs) 515148626bSAmir Goldstein return ofs->upper_mnt->mnt_sb; 525148626bSAmir Goldstein else if (ofs->numlowerfs == 1 && !ofs->upper_mnt) 535148626bSAmir Goldstein return ofs->lower_fs[0].sb; 545148626bSAmir Goldstein else 555148626bSAmir Goldstein return NULL; 567bcd74b9SAmir Goldstein } 577bcd74b9SAmir Goldstein 58e487d889SAmir Goldstein /* 59e487d889SAmir Goldstein * Check if underlying fs supports file handles and try to determine encoding 60e487d889SAmir Goldstein * type, in order to deduce maximum inode number used by fs. 61e487d889SAmir Goldstein * 62e487d889SAmir Goldstein * Return 0 if file handles are not supported. 63e487d889SAmir Goldstein * Return 1 (FILEID_INO32_GEN) if fs uses the default 32bit inode encoding. 64e487d889SAmir Goldstein * Return -1 if fs uses a non default encoding with unknown inode size. 65e487d889SAmir Goldstein */ 66e487d889SAmir Goldstein int ovl_can_decode_fh(struct super_block *sb) 6702bcd157SAmir Goldstein { 68e487d889SAmir Goldstein if (!sb->s_export_op || !sb->s_export_op->fh_to_dentry || 69e487d889SAmir Goldstein uuid_is_null(&sb->s_uuid)) 70e487d889SAmir Goldstein return 0; 71e487d889SAmir Goldstein 72e487d889SAmir Goldstein return sb->s_export_op->encode_fh ? -1 : FILEID_INO32_GEN; 7302bcd157SAmir Goldstein } 7402bcd157SAmir Goldstein 7502bcd157SAmir Goldstein struct dentry *ovl_indexdir(struct super_block *sb) 7602bcd157SAmir Goldstein { 7702bcd157SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 7802bcd157SAmir Goldstein 7902bcd157SAmir Goldstein return ofs->indexdir; 8002bcd157SAmir Goldstein } 8102bcd157SAmir Goldstein 82f168f109SAmir Goldstein /* Index all files on copy up. For now only enabled for NFS export */ 83f168f109SAmir Goldstein bool ovl_index_all(struct super_block *sb) 84f168f109SAmir Goldstein { 85f168f109SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 86f168f109SAmir Goldstein 87f168f109SAmir Goldstein return ofs->config.nfs_export && ofs->config.index; 88f168f109SAmir Goldstein } 89f168f109SAmir Goldstein 90f168f109SAmir Goldstein /* Verify lower origin on lookup. For now only enabled for NFS export */ 91f168f109SAmir Goldstein bool ovl_verify_lower(struct super_block *sb) 92f168f109SAmir Goldstein { 93f168f109SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 94f168f109SAmir Goldstein 95f168f109SAmir Goldstein return ofs->config.nfs_export && ofs->config.index; 96f168f109SAmir Goldstein } 97f168f109SAmir Goldstein 98bbb1e54dSMiklos Szeredi struct ovl_entry *ovl_alloc_entry(unsigned int numlower) 99bbb1e54dSMiklos Szeredi { 100bbb1e54dSMiklos Szeredi size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); 101bbb1e54dSMiklos Szeredi struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); 102bbb1e54dSMiklos Szeredi 103bbb1e54dSMiklos Szeredi if (oe) 104bbb1e54dSMiklos Szeredi oe->numlower = numlower; 105bbb1e54dSMiklos Szeredi 106bbb1e54dSMiklos Szeredi return oe; 107bbb1e54dSMiklos Szeredi } 108bbb1e54dSMiklos Szeredi 109bbb1e54dSMiklos Szeredi bool ovl_dentry_remote(struct dentry *dentry) 110bbb1e54dSMiklos Szeredi { 111bbb1e54dSMiklos Szeredi return dentry->d_flags & 112bbb1e54dSMiklos Szeredi (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | 113bbb1e54dSMiklos Szeredi DCACHE_OP_REAL); 114bbb1e54dSMiklos Szeredi } 115bbb1e54dSMiklos Szeredi 116bbb1e54dSMiklos Szeredi bool ovl_dentry_weird(struct dentry *dentry) 117bbb1e54dSMiklos Szeredi { 118bbb1e54dSMiklos Szeredi return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | 119bbb1e54dSMiklos Szeredi DCACHE_MANAGE_TRANSIT | 120bbb1e54dSMiklos Szeredi DCACHE_OP_HASH | 121bbb1e54dSMiklos Szeredi DCACHE_OP_COMPARE); 122bbb1e54dSMiklos Szeredi } 123bbb1e54dSMiklos Szeredi 124bbb1e54dSMiklos Szeredi enum ovl_path_type ovl_path_type(struct dentry *dentry) 125bbb1e54dSMiklos Szeredi { 126bbb1e54dSMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 127bbb1e54dSMiklos Szeredi enum ovl_path_type type = 0; 128bbb1e54dSMiklos Szeredi 12909d8b586SMiklos Szeredi if (ovl_dentry_upper(dentry)) { 130bbb1e54dSMiklos Szeredi type = __OVL_PATH_UPPER; 131bbb1e54dSMiklos Szeredi 132bbb1e54dSMiklos Szeredi /* 13359548503SAmir Goldstein * Non-dir dentry can hold lower dentry of its copy up origin. 134bbb1e54dSMiklos Szeredi */ 13559548503SAmir Goldstein if (oe->numlower) { 13659548503SAmir Goldstein type |= __OVL_PATH_ORIGIN; 13759548503SAmir Goldstein if (d_is_dir(dentry)) 138bbb1e54dSMiklos Szeredi type |= __OVL_PATH_MERGE; 13959548503SAmir Goldstein } 140bbb1e54dSMiklos Szeredi } else { 141bbb1e54dSMiklos Szeredi if (oe->numlower > 1) 142bbb1e54dSMiklos Szeredi type |= __OVL_PATH_MERGE; 143bbb1e54dSMiklos Szeredi } 144bbb1e54dSMiklos Szeredi return type; 145bbb1e54dSMiklos Szeredi } 146bbb1e54dSMiklos Szeredi 147bbb1e54dSMiklos Szeredi void ovl_path_upper(struct dentry *dentry, struct path *path) 148bbb1e54dSMiklos Szeredi { 149bbb1e54dSMiklos Szeredi struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 150bbb1e54dSMiklos Szeredi 151bbb1e54dSMiklos Szeredi path->mnt = ofs->upper_mnt; 15209d8b586SMiklos Szeredi path->dentry = ovl_dentry_upper(dentry); 153bbb1e54dSMiklos Szeredi } 154bbb1e54dSMiklos Szeredi 155bbb1e54dSMiklos Szeredi void ovl_path_lower(struct dentry *dentry, struct path *path) 156bbb1e54dSMiklos Szeredi { 157bbb1e54dSMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 158bbb1e54dSMiklos Szeredi 159b9343632SChandan Rajendra if (oe->numlower) { 160b9343632SChandan Rajendra path->mnt = oe->lowerstack[0].layer->mnt; 161b9343632SChandan Rajendra path->dentry = oe->lowerstack[0].dentry; 162b9343632SChandan Rajendra } else { 163b9343632SChandan Rajendra *path = (struct path) { }; 164b9343632SChandan Rajendra } 165bbb1e54dSMiklos Szeredi } 166bbb1e54dSMiklos Szeredi 1674f93b426SVivek Goyal void ovl_path_lowerdata(struct dentry *dentry, struct path *path) 1684f93b426SVivek Goyal { 1694f93b426SVivek Goyal struct ovl_entry *oe = dentry->d_fsdata; 1704f93b426SVivek Goyal 1714f93b426SVivek Goyal if (oe->numlower) { 1724f93b426SVivek Goyal path->mnt = oe->lowerstack[oe->numlower - 1].layer->mnt; 1734f93b426SVivek Goyal path->dentry = oe->lowerstack[oe->numlower - 1].dentry; 1744f93b426SVivek Goyal } else { 1754f93b426SVivek Goyal *path = (struct path) { }; 1764f93b426SVivek Goyal } 1774f93b426SVivek Goyal } 1784f93b426SVivek Goyal 179bbb1e54dSMiklos Szeredi enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) 180bbb1e54dSMiklos Szeredi { 181bbb1e54dSMiklos Szeredi enum ovl_path_type type = ovl_path_type(dentry); 182bbb1e54dSMiklos Szeredi 183bbb1e54dSMiklos Szeredi if (!OVL_TYPE_UPPER(type)) 184bbb1e54dSMiklos Szeredi ovl_path_lower(dentry, path); 185bbb1e54dSMiklos Szeredi else 186bbb1e54dSMiklos Szeredi ovl_path_upper(dentry, path); 187bbb1e54dSMiklos Szeredi 188bbb1e54dSMiklos Szeredi return type; 189bbb1e54dSMiklos Szeredi } 190bbb1e54dSMiklos Szeredi 191bbb1e54dSMiklos Szeredi struct dentry *ovl_dentry_upper(struct dentry *dentry) 192bbb1e54dSMiklos Szeredi { 19309d8b586SMiklos Szeredi return ovl_upperdentry_dereference(OVL_I(d_inode(dentry))); 194bbb1e54dSMiklos Szeredi } 195bbb1e54dSMiklos Szeredi 196bbb1e54dSMiklos Szeredi struct dentry *ovl_dentry_lower(struct dentry *dentry) 197bbb1e54dSMiklos Szeredi { 198bbb1e54dSMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 199bbb1e54dSMiklos Szeredi 20009d8b586SMiklos Szeredi return oe->numlower ? oe->lowerstack[0].dentry : NULL; 201bbb1e54dSMiklos Szeredi } 202bbb1e54dSMiklos Szeredi 203da309e8cSAmir Goldstein struct ovl_layer *ovl_layer_lower(struct dentry *dentry) 204da309e8cSAmir Goldstein { 205da309e8cSAmir Goldstein struct ovl_entry *oe = dentry->d_fsdata; 206da309e8cSAmir Goldstein 207da309e8cSAmir Goldstein return oe->numlower ? oe->lowerstack[0].layer : NULL; 208da309e8cSAmir Goldstein } 209da309e8cSAmir Goldstein 210bbb1e54dSMiklos Szeredi struct dentry *ovl_dentry_real(struct dentry *dentry) 211bbb1e54dSMiklos Szeredi { 21209d8b586SMiklos Szeredi return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); 213bbb1e54dSMiklos Szeredi } 214bbb1e54dSMiklos Szeredi 2151d88f183SMiklos Szeredi struct dentry *ovl_i_dentry_upper(struct inode *inode) 2161d88f183SMiklos Szeredi { 2171d88f183SMiklos Szeredi return ovl_upperdentry_dereference(OVL_I(inode)); 2181d88f183SMiklos Szeredi } 2191d88f183SMiklos Szeredi 22009d8b586SMiklos Szeredi struct inode *ovl_inode_upper(struct inode *inode) 22125b7713aSMiklos Szeredi { 2221d88f183SMiklos Szeredi struct dentry *upperdentry = ovl_i_dentry_upper(inode); 22325b7713aSMiklos Szeredi 22409d8b586SMiklos Szeredi return upperdentry ? d_inode(upperdentry) : NULL; 22525b7713aSMiklos Szeredi } 22625b7713aSMiklos Szeredi 22709d8b586SMiklos Szeredi struct inode *ovl_inode_lower(struct inode *inode) 22809d8b586SMiklos Szeredi { 22909d8b586SMiklos Szeredi return OVL_I(inode)->lower; 23009d8b586SMiklos Szeredi } 23109d8b586SMiklos Szeredi 23209d8b586SMiklos Szeredi struct inode *ovl_inode_real(struct inode *inode) 23309d8b586SMiklos Szeredi { 23409d8b586SMiklos Szeredi return ovl_inode_upper(inode) ?: ovl_inode_lower(inode); 23509d8b586SMiklos Szeredi } 23609d8b586SMiklos Szeredi 23709d8b586SMiklos Szeredi 2384edb83bbSMiklos Szeredi struct ovl_dir_cache *ovl_dir_cache(struct inode *inode) 239bbb1e54dSMiklos Szeredi { 2404edb83bbSMiklos Szeredi return OVL_I(inode)->cache; 241bbb1e54dSMiklos Szeredi } 242bbb1e54dSMiklos Szeredi 2434edb83bbSMiklos Szeredi void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) 244bbb1e54dSMiklos Szeredi { 2454edb83bbSMiklos Szeredi OVL_I(inode)->cache = cache; 246bbb1e54dSMiklos Szeredi } 247bbb1e54dSMiklos Szeredi 248c62520a8SAmir Goldstein void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry) 249c62520a8SAmir Goldstein { 250c62520a8SAmir Goldstein set_bit(flag, &OVL_E(dentry)->flags); 251c62520a8SAmir Goldstein } 252c62520a8SAmir Goldstein 253c62520a8SAmir Goldstein void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry) 254c62520a8SAmir Goldstein { 255c62520a8SAmir Goldstein clear_bit(flag, &OVL_E(dentry)->flags); 256c62520a8SAmir Goldstein } 257c62520a8SAmir Goldstein 258c62520a8SAmir Goldstein bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry) 259c62520a8SAmir Goldstein { 260c62520a8SAmir Goldstein return test_bit(flag, &OVL_E(dentry)->flags); 261c62520a8SAmir Goldstein } 262c62520a8SAmir Goldstein 263bbb1e54dSMiklos Szeredi bool ovl_dentry_is_opaque(struct dentry *dentry) 264bbb1e54dSMiklos Szeredi { 265c62520a8SAmir Goldstein return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry); 266bbb1e54dSMiklos Szeredi } 267bbb1e54dSMiklos Szeredi 268bbb1e54dSMiklos Szeredi bool ovl_dentry_is_whiteout(struct dentry *dentry) 269bbb1e54dSMiklos Szeredi { 270bbb1e54dSMiklos Szeredi return !dentry->d_inode && ovl_dentry_is_opaque(dentry); 271bbb1e54dSMiklos Szeredi } 272bbb1e54dSMiklos Szeredi 2735cf5b477SMiklos Szeredi void ovl_dentry_set_opaque(struct dentry *dentry) 274bbb1e54dSMiklos Szeredi { 275c62520a8SAmir Goldstein ovl_dentry_set_flag(OVL_E_OPAQUE, dentry); 276bbb1e54dSMiklos Szeredi } 277bbb1e54dSMiklos Szeredi 27855acc661SMiklos Szeredi /* 279aa3ff3c1SAmir Goldstein * For hard links and decoded file handles, it's possible for ovl_dentry_upper() 280aa3ff3c1SAmir Goldstein * to return positive, while there's no actual upper alias for the inode. 281aa3ff3c1SAmir Goldstein * Copy up code needs to know about the existence of the upper alias, so it 282aa3ff3c1SAmir Goldstein * can't use ovl_dentry_upper(). 28355acc661SMiklos Szeredi */ 28455acc661SMiklos Szeredi bool ovl_dentry_has_upper_alias(struct dentry *dentry) 28555acc661SMiklos Szeredi { 286c62520a8SAmir Goldstein return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry); 28755acc661SMiklos Szeredi } 28855acc661SMiklos Szeredi 28955acc661SMiklos Szeredi void ovl_dentry_set_upper_alias(struct dentry *dentry) 29055acc661SMiklos Szeredi { 291c62520a8SAmir Goldstein ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry); 29255acc661SMiklos Szeredi } 29355acc661SMiklos Szeredi 2940c288874SVivek Goyal static bool ovl_should_check_upperdata(struct inode *inode) 2950c288874SVivek Goyal { 2960c288874SVivek Goyal if (!S_ISREG(inode->i_mode)) 2970c288874SVivek Goyal return false; 2980c288874SVivek Goyal 2990c288874SVivek Goyal if (!ovl_inode_lower(inode)) 3000c288874SVivek Goyal return false; 3010c288874SVivek Goyal 3020c288874SVivek Goyal return true; 3030c288874SVivek Goyal } 3040c288874SVivek Goyal 3050c288874SVivek Goyal bool ovl_has_upperdata(struct inode *inode) 3060c288874SVivek Goyal { 3070c288874SVivek Goyal if (!ovl_should_check_upperdata(inode)) 3080c288874SVivek Goyal return true; 3090c288874SVivek Goyal 3100c288874SVivek Goyal if (!ovl_test_flag(OVL_UPPERDATA, inode)) 3110c288874SVivek Goyal return false; 3120c288874SVivek Goyal /* 3130c288874SVivek Goyal * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of 3140c288874SVivek Goyal * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure 3150c288874SVivek Goyal * if setting of OVL_UPPERDATA is visible, then effects of writes 3160c288874SVivek Goyal * before that are visible too. 3170c288874SVivek Goyal */ 3180c288874SVivek Goyal smp_rmb(); 3190c288874SVivek Goyal return true; 3200c288874SVivek Goyal } 3210c288874SVivek Goyal 3220c288874SVivek Goyal void ovl_set_upperdata(struct inode *inode) 3230c288874SVivek Goyal { 3240c288874SVivek Goyal /* 3250c288874SVivek Goyal * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure 3260c288874SVivek Goyal * if OVL_UPPERDATA flag is visible, then effects of write operations 3270c288874SVivek Goyal * before it are visible as well. 3280c288874SVivek Goyal */ 3290c288874SVivek Goyal smp_wmb(); 3300c288874SVivek Goyal ovl_set_flag(OVL_UPPERDATA, inode); 3310c288874SVivek Goyal } 3320c288874SVivek Goyal 3330c288874SVivek Goyal /* Caller should hold ovl_inode->lock */ 3340c288874SVivek Goyal bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags) 3350c288874SVivek Goyal { 3360c288874SVivek Goyal if (!ovl_open_flags_need_copy_up(flags)) 3370c288874SVivek Goyal return false; 3380c288874SVivek Goyal 3390c288874SVivek Goyal return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry)); 3400c288874SVivek Goyal } 3410c288874SVivek Goyal 3420c288874SVivek Goyal bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) 3430c288874SVivek Goyal { 3440c288874SVivek Goyal if (!ovl_open_flags_need_copy_up(flags)) 3450c288874SVivek Goyal return false; 3460c288874SVivek Goyal 3470c288874SVivek Goyal return !ovl_has_upperdata(d_inode(dentry)); 3480c288874SVivek Goyal } 3490c288874SVivek Goyal 350a6c60655SMiklos Szeredi bool ovl_redirect_dir(struct super_block *sb) 351a6c60655SMiklos Szeredi { 352a6c60655SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 353a6c60655SMiklos Szeredi 35421a22878SAmir Goldstein return ofs->config.redirect_dir && !ofs->noxattr; 355a6c60655SMiklos Szeredi } 356a6c60655SMiklos Szeredi 357a6c60655SMiklos Szeredi const char *ovl_dentry_get_redirect(struct dentry *dentry) 358a6c60655SMiklos Szeredi { 359cf31c463SMiklos Szeredi return OVL_I(d_inode(dentry))->redirect; 360a6c60655SMiklos Szeredi } 361a6c60655SMiklos Szeredi 362a6c60655SMiklos Szeredi void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) 363a6c60655SMiklos Szeredi { 364cf31c463SMiklos Szeredi struct ovl_inode *oi = OVL_I(d_inode(dentry)); 365a6c60655SMiklos Szeredi 366cf31c463SMiklos Szeredi kfree(oi->redirect); 367cf31c463SMiklos Szeredi oi->redirect = redirect; 368a6c60655SMiklos Szeredi } 369a6c60655SMiklos Szeredi 37009d8b586SMiklos Szeredi void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, 37109d8b586SMiklos Szeredi struct dentry *lowerdentry) 372bbb1e54dSMiklos Szeredi { 373695b46e7SAmir Goldstein struct inode *realinode = d_inode(upperdentry ?: lowerdentry); 374695b46e7SAmir Goldstein 37509d8b586SMiklos Szeredi if (upperdentry) 37609d8b586SMiklos Szeredi OVL_I(inode)->__upperdentry = upperdentry; 37709d8b586SMiklos Szeredi if (lowerdentry) 37831747edaSAmir Goldstein OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); 379bbb1e54dSMiklos Szeredi 380695b46e7SAmir Goldstein ovl_copyattr(realinode, inode); 3814f357295SMiklos Szeredi ovl_copyflags(realinode, inode); 382695b46e7SAmir Goldstein if (!inode->i_ino) 383695b46e7SAmir Goldstein inode->i_ino = realinode->i_ino; 384bbb1e54dSMiklos Szeredi } 385bbb1e54dSMiklos Szeredi 38609d8b586SMiklos Szeredi void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) 387bbb1e54dSMiklos Szeredi { 38809d8b586SMiklos Szeredi struct inode *upperinode = d_inode(upperdentry); 389e6d2ebddSMiklos Szeredi 39009d8b586SMiklos Szeredi WARN_ON(OVL_I(inode)->__upperdentry); 39109d8b586SMiklos Szeredi 39225b7713aSMiklos Szeredi /* 39309d8b586SMiklos Szeredi * Make sure upperdentry is consistent before making it visible 39425b7713aSMiklos Szeredi */ 39525b7713aSMiklos Szeredi smp_wmb(); 39609d8b586SMiklos Szeredi OVL_I(inode)->__upperdentry = upperdentry; 39731747edaSAmir Goldstein if (inode_unhashed(inode)) { 398695b46e7SAmir Goldstein if (!inode->i_ino) 399695b46e7SAmir Goldstein inode->i_ino = upperinode->i_ino; 40025b7713aSMiklos Szeredi inode->i_private = upperinode; 401bbb1e54dSMiklos Szeredi __insert_inode_hash(inode, (unsigned long) upperinode); 402bbb1e54dSMiklos Szeredi } 40325b7713aSMiklos Szeredi } 404bbb1e54dSMiklos Szeredi 405d9854c87SMiklos Szeredi static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) 406bbb1e54dSMiklos Szeredi { 40704a01ac7SMiklos Szeredi struct inode *inode = d_inode(dentry); 408bbb1e54dSMiklos Szeredi 40904a01ac7SMiklos Szeredi WARN_ON(!inode_is_locked(inode)); 4104edb83bbSMiklos Szeredi /* 4114edb83bbSMiklos Szeredi * Version is used by readdir code to keep cache consistent. For merge 4124edb83bbSMiklos Szeredi * dirs all changes need to be noted. For non-merge dirs, cache only 4134edb83bbSMiklos Szeredi * contains impure (ones which have been copied up and have origins) 4144edb83bbSMiklos Szeredi * entries, so only need to note changes to impure entries. 4154edb83bbSMiklos Szeredi */ 4164edb83bbSMiklos Szeredi if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) 41704a01ac7SMiklos Szeredi OVL_I(inode)->version++; 418bbb1e54dSMiklos Szeredi } 419bbb1e54dSMiklos Szeredi 420d9854c87SMiklos Szeredi void ovl_dir_modified(struct dentry *dentry, bool impurity) 421d9854c87SMiklos Szeredi { 422d9854c87SMiklos Szeredi /* Copy mtime/ctime */ 423d9854c87SMiklos Szeredi ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); 424d9854c87SMiklos Szeredi 425d9854c87SMiklos Szeredi ovl_dentry_version_inc(dentry, impurity); 426d9854c87SMiklos Szeredi } 427d9854c87SMiklos Szeredi 428bbb1e54dSMiklos Szeredi u64 ovl_dentry_version_get(struct dentry *dentry) 429bbb1e54dSMiklos Szeredi { 43004a01ac7SMiklos Szeredi struct inode *inode = d_inode(dentry); 431bbb1e54dSMiklos Szeredi 43204a01ac7SMiklos Szeredi WARN_ON(!inode_is_locked(inode)); 43304a01ac7SMiklos Szeredi return OVL_I(inode)->version; 434bbb1e54dSMiklos Szeredi } 435bbb1e54dSMiklos Szeredi 436bbb1e54dSMiklos Szeredi bool ovl_is_whiteout(struct dentry *dentry) 437bbb1e54dSMiklos Szeredi { 438bbb1e54dSMiklos Szeredi struct inode *inode = dentry->d_inode; 439bbb1e54dSMiklos Szeredi 440bbb1e54dSMiklos Szeredi return inode && IS_WHITEOUT(inode); 441bbb1e54dSMiklos Szeredi } 442bbb1e54dSMiklos Szeredi 443bbb1e54dSMiklos Szeredi struct file *ovl_path_open(struct path *path, int flags) 444bbb1e54dSMiklos Szeredi { 445bbb1e54dSMiklos Szeredi return dentry_open(path, flags | O_NOATIME, current_cred()); 446bbb1e54dSMiklos Szeredi } 44739d3d60aSAmir Goldstein 4480c288874SVivek Goyal /* Caller should hold ovl_inode->lock */ 4490c288874SVivek Goyal static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags) 4500c288874SVivek Goyal { 4510c288874SVivek Goyal bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; 4520c288874SVivek Goyal 4530c288874SVivek Goyal if (ovl_dentry_upper(dentry) && 4540c288874SVivek Goyal (ovl_dentry_has_upper_alias(dentry) || disconnected) && 4550c288874SVivek Goyal !ovl_dentry_needs_data_copy_up_locked(dentry, flags)) 4560c288874SVivek Goyal return true; 4570c288874SVivek Goyal 4580c288874SVivek Goyal return false; 4590c288874SVivek Goyal } 4600c288874SVivek Goyal 4610c288874SVivek Goyal bool ovl_already_copied_up(struct dentry *dentry, int flags) 4622002df85SVivek Goyal { 4632002df85SVivek Goyal bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; 4642002df85SVivek Goyal 4652002df85SVivek Goyal /* 4662002df85SVivek Goyal * Check if copy-up has happened as well as for upper alias (in 4672002df85SVivek Goyal * case of hard links) is there. 4682002df85SVivek Goyal * 4692002df85SVivek Goyal * Both checks are lockless: 4702002df85SVivek Goyal * - false negatives: will recheck under oi->lock 4712002df85SVivek Goyal * - false positives: 4722002df85SVivek Goyal * + ovl_dentry_upper() uses memory barriers to ensure the 4732002df85SVivek Goyal * upper dentry is up-to-date 4742002df85SVivek Goyal * + ovl_dentry_has_upper_alias() relies on locking of 4752002df85SVivek Goyal * upper parent i_rwsem to prevent reordering copy-up 4762002df85SVivek Goyal * with rename. 4772002df85SVivek Goyal */ 4782002df85SVivek Goyal if (ovl_dentry_upper(dentry) && 4790c288874SVivek Goyal (ovl_dentry_has_upper_alias(dentry) || disconnected) && 4800c288874SVivek Goyal !ovl_dentry_needs_data_copy_up(dentry, flags)) 4812002df85SVivek Goyal return true; 4822002df85SVivek Goyal 4832002df85SVivek Goyal return false; 4842002df85SVivek Goyal } 4852002df85SVivek Goyal 4860c288874SVivek Goyal int ovl_copy_up_start(struct dentry *dentry, int flags) 48739d3d60aSAmir Goldstein { 488a015dafcSAmir Goldstein struct ovl_inode *oi = OVL_I(d_inode(dentry)); 48939d3d60aSAmir Goldstein int err; 49039d3d60aSAmir Goldstein 491a015dafcSAmir Goldstein err = mutex_lock_interruptible(&oi->lock); 4920c288874SVivek Goyal if (!err && ovl_already_copied_up_locked(dentry, flags)) { 49339d3d60aSAmir Goldstein err = 1; /* Already copied up */ 494a015dafcSAmir Goldstein mutex_unlock(&oi->lock); 49539d3d60aSAmir Goldstein } 49639d3d60aSAmir Goldstein 49739d3d60aSAmir Goldstein return err; 49839d3d60aSAmir Goldstein } 49939d3d60aSAmir Goldstein 50039d3d60aSAmir Goldstein void ovl_copy_up_end(struct dentry *dentry) 50139d3d60aSAmir Goldstein { 502a015dafcSAmir Goldstein mutex_unlock(&OVL_I(d_inode(dentry))->lock); 50339d3d60aSAmir Goldstein } 50482b749b2SAmir Goldstein 505b79e05aaSAmir Goldstein bool ovl_check_origin_xattr(struct dentry *dentry) 506b79e05aaSAmir Goldstein { 507b79e05aaSAmir Goldstein int res; 508b79e05aaSAmir Goldstein 509b79e05aaSAmir Goldstein res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); 510b79e05aaSAmir Goldstein 511b79e05aaSAmir Goldstein /* Zero size value means "copied up but origin unknown" */ 512b79e05aaSAmir Goldstein if (res >= 0) 513b79e05aaSAmir Goldstein return true; 514b79e05aaSAmir Goldstein 515b79e05aaSAmir Goldstein return false; 516b79e05aaSAmir Goldstein } 517b79e05aaSAmir Goldstein 518f3a15685SAmir Goldstein bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) 519f3a15685SAmir Goldstein { 520f3a15685SAmir Goldstein int res; 521f3a15685SAmir Goldstein char val; 522f3a15685SAmir Goldstein 523f3a15685SAmir Goldstein if (!d_is_dir(dentry)) 524f3a15685SAmir Goldstein return false; 525f3a15685SAmir Goldstein 526f3a15685SAmir Goldstein res = vfs_getxattr(dentry, name, &val, 1); 527f3a15685SAmir Goldstein if (res == 1 && val == 'y') 528f3a15685SAmir Goldstein return true; 529f3a15685SAmir Goldstein 530f3a15685SAmir Goldstein return false; 531f3a15685SAmir Goldstein } 532f3a15685SAmir Goldstein 53382b749b2SAmir Goldstein int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 53482b749b2SAmir Goldstein const char *name, const void *value, size_t size, 53582b749b2SAmir Goldstein int xerr) 53682b749b2SAmir Goldstein { 53782b749b2SAmir Goldstein int err; 53882b749b2SAmir Goldstein struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 53982b749b2SAmir Goldstein 54082b749b2SAmir Goldstein if (ofs->noxattr) 54182b749b2SAmir Goldstein return xerr; 54282b749b2SAmir Goldstein 54382b749b2SAmir Goldstein err = ovl_do_setxattr(upperdentry, name, value, size, 0); 54482b749b2SAmir Goldstein 54582b749b2SAmir Goldstein if (err == -EOPNOTSUPP) { 54682b749b2SAmir Goldstein pr_warn("overlayfs: cannot set %s xattr on upper\n", name); 54782b749b2SAmir Goldstein ofs->noxattr = true; 54882b749b2SAmir Goldstein return xerr; 54982b749b2SAmir Goldstein } 55082b749b2SAmir Goldstein 55182b749b2SAmir Goldstein return err; 55282b749b2SAmir Goldstein } 553f3a15685SAmir Goldstein 554f3a15685SAmir Goldstein int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) 555f3a15685SAmir Goldstein { 556f3a15685SAmir Goldstein int err; 557f3a15685SAmir Goldstein 55813c72075SMiklos Szeredi if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) 559f3a15685SAmir Goldstein return 0; 560f3a15685SAmir Goldstein 561f3a15685SAmir Goldstein /* 562f3a15685SAmir Goldstein * Do not fail when upper doesn't support xattrs. 563f3a15685SAmir Goldstein * Upper inodes won't have origin nor redirect xattr anyway. 564f3a15685SAmir Goldstein */ 565f3a15685SAmir Goldstein err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, 566f3a15685SAmir Goldstein "y", 1, 0); 567f3a15685SAmir Goldstein if (!err) 56813c72075SMiklos Szeredi ovl_set_flag(OVL_IMPURE, d_inode(dentry)); 569f3a15685SAmir Goldstein 570f3a15685SAmir Goldstein return err; 571f3a15685SAmir Goldstein } 57213c72075SMiklos Szeredi 57313c72075SMiklos Szeredi void ovl_set_flag(unsigned long flag, struct inode *inode) 57413c72075SMiklos Szeredi { 57513c72075SMiklos Szeredi set_bit(flag, &OVL_I(inode)->flags); 57613c72075SMiklos Szeredi } 57713c72075SMiklos Szeredi 5784edb83bbSMiklos Szeredi void ovl_clear_flag(unsigned long flag, struct inode *inode) 5794edb83bbSMiklos Szeredi { 5804edb83bbSMiklos Szeredi clear_bit(flag, &OVL_I(inode)->flags); 5814edb83bbSMiklos Szeredi } 5824edb83bbSMiklos Szeredi 58313c72075SMiklos Szeredi bool ovl_test_flag(unsigned long flag, struct inode *inode) 58413c72075SMiklos Szeredi { 58513c72075SMiklos Szeredi return test_bit(flag, &OVL_I(inode)->flags); 58613c72075SMiklos Szeredi } 587ad0af710SAmir Goldstein 588ad0af710SAmir Goldstein /** 589ad0af710SAmir Goldstein * Caller must hold a reference to inode to prevent it from being freed while 590ad0af710SAmir Goldstein * it is marked inuse. 591ad0af710SAmir Goldstein */ 592ad0af710SAmir Goldstein bool ovl_inuse_trylock(struct dentry *dentry) 593ad0af710SAmir Goldstein { 594ad0af710SAmir Goldstein struct inode *inode = d_inode(dentry); 595ad0af710SAmir Goldstein bool locked = false; 596ad0af710SAmir Goldstein 597ad0af710SAmir Goldstein spin_lock(&inode->i_lock); 598ad0af710SAmir Goldstein if (!(inode->i_state & I_OVL_INUSE)) { 599ad0af710SAmir Goldstein inode->i_state |= I_OVL_INUSE; 600ad0af710SAmir Goldstein locked = true; 601ad0af710SAmir Goldstein } 602ad0af710SAmir Goldstein spin_unlock(&inode->i_lock); 603ad0af710SAmir Goldstein 604ad0af710SAmir Goldstein return locked; 605ad0af710SAmir Goldstein } 606ad0af710SAmir Goldstein 607ad0af710SAmir Goldstein void ovl_inuse_unlock(struct dentry *dentry) 608ad0af710SAmir Goldstein { 609ad0af710SAmir Goldstein if (dentry) { 610ad0af710SAmir Goldstein struct inode *inode = d_inode(dentry); 611ad0af710SAmir Goldstein 612ad0af710SAmir Goldstein spin_lock(&inode->i_lock); 613ad0af710SAmir Goldstein WARN_ON(!(inode->i_state & I_OVL_INUSE)); 614ad0af710SAmir Goldstein inode->i_state &= ~I_OVL_INUSE; 615ad0af710SAmir Goldstein spin_unlock(&inode->i_lock); 616ad0af710SAmir Goldstein } 617ad0af710SAmir Goldstein } 6185f8415d6SAmir Goldstein 61924b33ee1SAmir Goldstein /* 62024b33ee1SAmir Goldstein * Does this overlay dentry need to be indexed on copy up? 62124b33ee1SAmir Goldstein */ 62224b33ee1SAmir Goldstein bool ovl_need_index(struct dentry *dentry) 62324b33ee1SAmir Goldstein { 62424b33ee1SAmir Goldstein struct dentry *lower = ovl_dentry_lower(dentry); 62524b33ee1SAmir Goldstein 62624b33ee1SAmir Goldstein if (!lower || !ovl_indexdir(dentry->d_sb)) 62724b33ee1SAmir Goldstein return false; 62824b33ee1SAmir Goldstein 629fbd2d207SAmir Goldstein /* Index all files for NFS export and consistency verification */ 630016b720fSAmir Goldstein if (ovl_index_all(dentry->d_sb)) 631fbd2d207SAmir Goldstein return true; 632fbd2d207SAmir Goldstein 63324b33ee1SAmir Goldstein /* Index only lower hardlinks on copy up */ 63424b33ee1SAmir Goldstein if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1) 63524b33ee1SAmir Goldstein return true; 63624b33ee1SAmir Goldstein 63724b33ee1SAmir Goldstein return false; 63824b33ee1SAmir Goldstein } 63924b33ee1SAmir Goldstein 6409f4ec904SAmir Goldstein /* Caller must hold OVL_I(inode)->lock */ 641caf70cb2SAmir Goldstein static void ovl_cleanup_index(struct dentry *dentry) 642caf70cb2SAmir Goldstein { 643e7dd0e71SAmir Goldstein struct dentry *indexdir = ovl_indexdir(dentry->d_sb); 644e7dd0e71SAmir Goldstein struct inode *dir = indexdir->d_inode; 645caf70cb2SAmir Goldstein struct dentry *lowerdentry = ovl_dentry_lower(dentry); 646caf70cb2SAmir Goldstein struct dentry *upperdentry = ovl_dentry_upper(dentry); 647caf70cb2SAmir Goldstein struct dentry *index = NULL; 648caf70cb2SAmir Goldstein struct inode *inode; 649caf70cb2SAmir Goldstein struct qstr name; 650caf70cb2SAmir Goldstein int err; 651caf70cb2SAmir Goldstein 652caf70cb2SAmir Goldstein err = ovl_get_index_name(lowerdentry, &name); 653caf70cb2SAmir Goldstein if (err) 654caf70cb2SAmir Goldstein goto fail; 655caf70cb2SAmir Goldstein 656caf70cb2SAmir Goldstein inode = d_inode(upperdentry); 65789a17556SAmir Goldstein if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { 658caf70cb2SAmir Goldstein pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", 659caf70cb2SAmir Goldstein upperdentry, inode->i_ino, inode->i_nlink); 660caf70cb2SAmir Goldstein /* 661caf70cb2SAmir Goldstein * We either have a bug with persistent union nlink or a lower 662caf70cb2SAmir Goldstein * hardlink was added while overlay is mounted. Adding a lower 663caf70cb2SAmir Goldstein * hardlink and then unlinking all overlay hardlinks would drop 664caf70cb2SAmir Goldstein * overlay nlink to zero before all upper inodes are unlinked. 665caf70cb2SAmir Goldstein * As a safety measure, when that situation is detected, set 666caf70cb2SAmir Goldstein * the overlay nlink to the index inode nlink minus one for the 667caf70cb2SAmir Goldstein * index entry itself. 668caf70cb2SAmir Goldstein */ 669caf70cb2SAmir Goldstein set_nlink(d_inode(dentry), inode->i_nlink - 1); 670caf70cb2SAmir Goldstein ovl_set_nlink_upper(dentry); 671caf70cb2SAmir Goldstein goto out; 672caf70cb2SAmir Goldstein } 673caf70cb2SAmir Goldstein 674caf70cb2SAmir Goldstein inode_lock_nested(dir, I_MUTEX_PARENT); 675e7dd0e71SAmir Goldstein index = lookup_one_len(name.name, indexdir, name.len); 676caf70cb2SAmir Goldstein err = PTR_ERR(index); 677e7dd0e71SAmir Goldstein if (IS_ERR(index)) { 6789f4ec904SAmir Goldstein index = NULL; 679e7dd0e71SAmir Goldstein } else if (ovl_index_all(dentry->d_sb)) { 680e7dd0e71SAmir Goldstein /* Whiteout orphan index to block future open by handle */ 681e7dd0e71SAmir Goldstein err = ovl_cleanup_and_whiteout(indexdir, dir, index); 682e7dd0e71SAmir Goldstein } else { 683e7dd0e71SAmir Goldstein /* Cleanup orphan index entries */ 684e7dd0e71SAmir Goldstein err = ovl_cleanup(dir, index); 685e7dd0e71SAmir Goldstein } 6869f4ec904SAmir Goldstein 687caf70cb2SAmir Goldstein inode_unlock(dir); 688caf70cb2SAmir Goldstein if (err) 689caf70cb2SAmir Goldstein goto fail; 690caf70cb2SAmir Goldstein 691caf70cb2SAmir Goldstein out: 692caf70cb2SAmir Goldstein dput(index); 693caf70cb2SAmir Goldstein return; 694caf70cb2SAmir Goldstein 695caf70cb2SAmir Goldstein fail: 696caf70cb2SAmir Goldstein pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err); 697caf70cb2SAmir Goldstein goto out; 698caf70cb2SAmir Goldstein } 699caf70cb2SAmir Goldstein 7005f8415d6SAmir Goldstein /* 7015f8415d6SAmir Goldstein * Operations that change overlay inode and upper inode nlink need to be 7025f8415d6SAmir Goldstein * synchronized with copy up for persistent nlink accounting. 7035f8415d6SAmir Goldstein */ 7045f8415d6SAmir Goldstein int ovl_nlink_start(struct dentry *dentry, bool *locked) 7055f8415d6SAmir Goldstein { 7065f8415d6SAmir Goldstein struct ovl_inode *oi = OVL_I(d_inode(dentry)); 7075f8415d6SAmir Goldstein const struct cred *old_cred; 7085f8415d6SAmir Goldstein int err; 7095f8415d6SAmir Goldstein 71089a17556SAmir Goldstein if (!d_inode(dentry)) 7115f8415d6SAmir Goldstein return 0; 7125f8415d6SAmir Goldstein 7135f8415d6SAmir Goldstein /* 7145f8415d6SAmir Goldstein * With inodes index is enabled, we store the union overlay nlink 71524b33ee1SAmir Goldstein * in an xattr on the index inode. When whiting out an indexed lower, 7165f8415d6SAmir Goldstein * we need to decrement the overlay persistent nlink, but before the 7175f8415d6SAmir Goldstein * first copy up, we have no upper index inode to store the xattr. 7185f8415d6SAmir Goldstein * 71924b33ee1SAmir Goldstein * As a workaround, before whiteout/rename over an indexed lower, 7205f8415d6SAmir Goldstein * copy up to create the upper index. Creating the upper index will 7215f8415d6SAmir Goldstein * initialize the overlay nlink, so it could be dropped if unlink 7225f8415d6SAmir Goldstein * or rename succeeds. 7235f8415d6SAmir Goldstein * 7245f8415d6SAmir Goldstein * TODO: implement metadata only index copy up when called with 7255f8415d6SAmir Goldstein * ovl_copy_up_flags(dentry, O_PATH). 7265f8415d6SAmir Goldstein */ 72724b33ee1SAmir Goldstein if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) { 7285f8415d6SAmir Goldstein err = ovl_copy_up(dentry); 7295f8415d6SAmir Goldstein if (err) 7305f8415d6SAmir Goldstein return err; 7315f8415d6SAmir Goldstein } 7325f8415d6SAmir Goldstein 7335f8415d6SAmir Goldstein err = mutex_lock_interruptible(&oi->lock); 7345f8415d6SAmir Goldstein if (err) 7355f8415d6SAmir Goldstein return err; 7365f8415d6SAmir Goldstein 73789a17556SAmir Goldstein if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry))) 7385f8415d6SAmir Goldstein goto out; 7395f8415d6SAmir Goldstein 7405f8415d6SAmir Goldstein old_cred = ovl_override_creds(dentry->d_sb); 7415f8415d6SAmir Goldstein /* 7425f8415d6SAmir Goldstein * The overlay inode nlink should be incremented/decremented IFF the 7435f8415d6SAmir Goldstein * upper operation succeeds, along with nlink change of upper inode. 7445f8415d6SAmir Goldstein * Therefore, before link/unlink/rename, we store the union nlink 7455f8415d6SAmir Goldstein * value relative to the upper inode nlink in an upper inode xattr. 7465f8415d6SAmir Goldstein */ 7475f8415d6SAmir Goldstein err = ovl_set_nlink_upper(dentry); 7485f8415d6SAmir Goldstein revert_creds(old_cred); 7495f8415d6SAmir Goldstein 7505f8415d6SAmir Goldstein out: 7515f8415d6SAmir Goldstein if (err) 7525f8415d6SAmir Goldstein mutex_unlock(&oi->lock); 7535f8415d6SAmir Goldstein else 7545f8415d6SAmir Goldstein *locked = true; 7555f8415d6SAmir Goldstein 7565f8415d6SAmir Goldstein return err; 7575f8415d6SAmir Goldstein } 7585f8415d6SAmir Goldstein 7595f8415d6SAmir Goldstein void ovl_nlink_end(struct dentry *dentry, bool locked) 7605f8415d6SAmir Goldstein { 761caf70cb2SAmir Goldstein if (locked) { 762caf70cb2SAmir Goldstein if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) && 763caf70cb2SAmir Goldstein d_inode(dentry)->i_nlink == 0) { 764caf70cb2SAmir Goldstein const struct cred *old_cred; 765caf70cb2SAmir Goldstein 766caf70cb2SAmir Goldstein old_cred = ovl_override_creds(dentry->d_sb); 767caf70cb2SAmir Goldstein ovl_cleanup_index(dentry); 768caf70cb2SAmir Goldstein revert_creds(old_cred); 769caf70cb2SAmir Goldstein } 770caf70cb2SAmir Goldstein 7715f8415d6SAmir Goldstein mutex_unlock(&OVL_I(d_inode(dentry))->lock); 7725f8415d6SAmir Goldstein } 773caf70cb2SAmir Goldstein } 7745820dc08SAmir Goldstein 7755820dc08SAmir Goldstein int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) 7765820dc08SAmir Goldstein { 7775820dc08SAmir Goldstein /* Workdir should not be the same as upperdir */ 7785820dc08SAmir Goldstein if (workdir == upperdir) 7795820dc08SAmir Goldstein goto err; 7805820dc08SAmir Goldstein 7815820dc08SAmir Goldstein /* Workdir should not be subdir of upperdir and vice versa */ 7825820dc08SAmir Goldstein if (lock_rename(workdir, upperdir) != NULL) 7835820dc08SAmir Goldstein goto err_unlock; 7845820dc08SAmir Goldstein 7855820dc08SAmir Goldstein return 0; 7865820dc08SAmir Goldstein 7875820dc08SAmir Goldstein err_unlock: 7885820dc08SAmir Goldstein unlock_rename(workdir, upperdir); 7895820dc08SAmir Goldstein err: 7905820dc08SAmir Goldstein pr_err("overlayfs: failed to lock workdir+upperdir\n"); 7915820dc08SAmir Goldstein return -EIO; 7925820dc08SAmir Goldstein } 7939d3dfea3SVivek Goyal 7949d3dfea3SVivek Goyal /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ 7959d3dfea3SVivek Goyal int ovl_check_metacopy_xattr(struct dentry *dentry) 7969d3dfea3SVivek Goyal { 7979d3dfea3SVivek Goyal int res; 7989d3dfea3SVivek Goyal 7999d3dfea3SVivek Goyal /* Only regular files can have metacopy xattr */ 8009d3dfea3SVivek Goyal if (!S_ISREG(d_inode(dentry)->i_mode)) 8019d3dfea3SVivek Goyal return 0; 8029d3dfea3SVivek Goyal 8039d3dfea3SVivek Goyal res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0); 8049d3dfea3SVivek Goyal if (res < 0) { 8059d3dfea3SVivek Goyal if (res == -ENODATA || res == -EOPNOTSUPP) 8069d3dfea3SVivek Goyal return 0; 8079d3dfea3SVivek Goyal goto out; 8089d3dfea3SVivek Goyal } 8099d3dfea3SVivek Goyal 8109d3dfea3SVivek Goyal return 1; 8119d3dfea3SVivek Goyal out: 8129d3dfea3SVivek Goyal pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res); 8139d3dfea3SVivek Goyal return res; 8149d3dfea3SVivek Goyal } 815