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 210647d253fSVivek Goyal /* 211647d253fSVivek Goyal * ovl_dentry_lower() could return either a data dentry or metacopy dentry 212647d253fSVivek Goyal * dependig on what is stored in lowerstack[0]. At times we need to find 213647d253fSVivek Goyal * lower dentry which has data (and not metacopy dentry). This helper 214647d253fSVivek Goyal * returns the lower data dentry. 215647d253fSVivek Goyal */ 216647d253fSVivek Goyal struct dentry *ovl_dentry_lowerdata(struct dentry *dentry) 217647d253fSVivek Goyal { 218647d253fSVivek Goyal struct ovl_entry *oe = dentry->d_fsdata; 219647d253fSVivek Goyal 220647d253fSVivek Goyal return oe->numlower ? oe->lowerstack[oe->numlower - 1].dentry : NULL; 221647d253fSVivek Goyal } 222647d253fSVivek Goyal 223bbb1e54dSMiklos Szeredi struct dentry *ovl_dentry_real(struct dentry *dentry) 224bbb1e54dSMiklos Szeredi { 22509d8b586SMiklos Szeredi return ovl_dentry_upper(dentry) ?: ovl_dentry_lower(dentry); 226bbb1e54dSMiklos Szeredi } 227bbb1e54dSMiklos Szeredi 2281d88f183SMiklos Szeredi struct dentry *ovl_i_dentry_upper(struct inode *inode) 2291d88f183SMiklos Szeredi { 2301d88f183SMiklos Szeredi return ovl_upperdentry_dereference(OVL_I(inode)); 2311d88f183SMiklos Szeredi } 2321d88f183SMiklos Szeredi 23309d8b586SMiklos Szeredi struct inode *ovl_inode_upper(struct inode *inode) 23425b7713aSMiklos Szeredi { 2351d88f183SMiklos Szeredi struct dentry *upperdentry = ovl_i_dentry_upper(inode); 23625b7713aSMiklos Szeredi 23709d8b586SMiklos Szeredi return upperdentry ? d_inode(upperdentry) : NULL; 23825b7713aSMiklos Szeredi } 23925b7713aSMiklos Szeredi 24009d8b586SMiklos Szeredi struct inode *ovl_inode_lower(struct inode *inode) 24109d8b586SMiklos Szeredi { 24209d8b586SMiklos Szeredi return OVL_I(inode)->lower; 24309d8b586SMiklos Szeredi } 24409d8b586SMiklos Szeredi 24509d8b586SMiklos Szeredi struct inode *ovl_inode_real(struct inode *inode) 24609d8b586SMiklos Szeredi { 24709d8b586SMiklos Szeredi return ovl_inode_upper(inode) ?: ovl_inode_lower(inode); 24809d8b586SMiklos Szeredi } 24909d8b586SMiklos Szeredi 2502664bd08SVivek Goyal /* Return inode which contains lower data. Do not return metacopy */ 2512664bd08SVivek Goyal struct inode *ovl_inode_lowerdata(struct inode *inode) 2522664bd08SVivek Goyal { 2532664bd08SVivek Goyal if (WARN_ON(!S_ISREG(inode->i_mode))) 2542664bd08SVivek Goyal return NULL; 2552664bd08SVivek Goyal 2562664bd08SVivek Goyal return OVL_I(inode)->lowerdata ?: ovl_inode_lower(inode); 2572664bd08SVivek Goyal } 25809d8b586SMiklos Szeredi 2594edb83bbSMiklos Szeredi struct ovl_dir_cache *ovl_dir_cache(struct inode *inode) 260bbb1e54dSMiklos Szeredi { 2614edb83bbSMiklos Szeredi return OVL_I(inode)->cache; 262bbb1e54dSMiklos Szeredi } 263bbb1e54dSMiklos Szeredi 2644edb83bbSMiklos Szeredi void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache) 265bbb1e54dSMiklos Szeredi { 2664edb83bbSMiklos Szeredi OVL_I(inode)->cache = cache; 267bbb1e54dSMiklos Szeredi } 268bbb1e54dSMiklos Szeredi 269c62520a8SAmir Goldstein void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry) 270c62520a8SAmir Goldstein { 271c62520a8SAmir Goldstein set_bit(flag, &OVL_E(dentry)->flags); 272c62520a8SAmir Goldstein } 273c62520a8SAmir Goldstein 274c62520a8SAmir Goldstein void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry) 275c62520a8SAmir Goldstein { 276c62520a8SAmir Goldstein clear_bit(flag, &OVL_E(dentry)->flags); 277c62520a8SAmir Goldstein } 278c62520a8SAmir Goldstein 279c62520a8SAmir Goldstein bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry) 280c62520a8SAmir Goldstein { 281c62520a8SAmir Goldstein return test_bit(flag, &OVL_E(dentry)->flags); 282c62520a8SAmir Goldstein } 283c62520a8SAmir Goldstein 284bbb1e54dSMiklos Szeredi bool ovl_dentry_is_opaque(struct dentry *dentry) 285bbb1e54dSMiklos Szeredi { 286c62520a8SAmir Goldstein return ovl_dentry_test_flag(OVL_E_OPAQUE, dentry); 287bbb1e54dSMiklos Szeredi } 288bbb1e54dSMiklos Szeredi 289bbb1e54dSMiklos Szeredi bool ovl_dentry_is_whiteout(struct dentry *dentry) 290bbb1e54dSMiklos Szeredi { 291bbb1e54dSMiklos Szeredi return !dentry->d_inode && ovl_dentry_is_opaque(dentry); 292bbb1e54dSMiklos Szeredi } 293bbb1e54dSMiklos Szeredi 2945cf5b477SMiklos Szeredi void ovl_dentry_set_opaque(struct dentry *dentry) 295bbb1e54dSMiklos Szeredi { 296c62520a8SAmir Goldstein ovl_dentry_set_flag(OVL_E_OPAQUE, dentry); 297bbb1e54dSMiklos Szeredi } 298bbb1e54dSMiklos Szeredi 29955acc661SMiklos Szeredi /* 300aa3ff3c1SAmir Goldstein * For hard links and decoded file handles, it's possible for ovl_dentry_upper() 301aa3ff3c1SAmir Goldstein * to return positive, while there's no actual upper alias for the inode. 302aa3ff3c1SAmir Goldstein * Copy up code needs to know about the existence of the upper alias, so it 303aa3ff3c1SAmir Goldstein * can't use ovl_dentry_upper(). 30455acc661SMiklos Szeredi */ 30555acc661SMiklos Szeredi bool ovl_dentry_has_upper_alias(struct dentry *dentry) 30655acc661SMiklos Szeredi { 307c62520a8SAmir Goldstein return ovl_dentry_test_flag(OVL_E_UPPER_ALIAS, dentry); 30855acc661SMiklos Szeredi } 30955acc661SMiklos Szeredi 31055acc661SMiklos Szeredi void ovl_dentry_set_upper_alias(struct dentry *dentry) 31155acc661SMiklos Szeredi { 312c62520a8SAmir Goldstein ovl_dentry_set_flag(OVL_E_UPPER_ALIAS, dentry); 31355acc661SMiklos Szeredi } 31455acc661SMiklos Szeredi 3150c288874SVivek Goyal static bool ovl_should_check_upperdata(struct inode *inode) 3160c288874SVivek Goyal { 3170c288874SVivek Goyal if (!S_ISREG(inode->i_mode)) 3180c288874SVivek Goyal return false; 3190c288874SVivek Goyal 3200c288874SVivek Goyal if (!ovl_inode_lower(inode)) 3210c288874SVivek Goyal return false; 3220c288874SVivek Goyal 3230c288874SVivek Goyal return true; 3240c288874SVivek Goyal } 3250c288874SVivek Goyal 3260c288874SVivek Goyal bool ovl_has_upperdata(struct inode *inode) 3270c288874SVivek Goyal { 3280c288874SVivek Goyal if (!ovl_should_check_upperdata(inode)) 3290c288874SVivek Goyal return true; 3300c288874SVivek Goyal 3310c288874SVivek Goyal if (!ovl_test_flag(OVL_UPPERDATA, inode)) 3320c288874SVivek Goyal return false; 3330c288874SVivek Goyal /* 3340c288874SVivek Goyal * Pairs with smp_wmb() in ovl_set_upperdata(). Main user of 3350c288874SVivek Goyal * ovl_has_upperdata() is ovl_copy_up_meta_inode_data(). Make sure 3360c288874SVivek Goyal * if setting of OVL_UPPERDATA is visible, then effects of writes 3370c288874SVivek Goyal * before that are visible too. 3380c288874SVivek Goyal */ 3390c288874SVivek Goyal smp_rmb(); 3400c288874SVivek Goyal return true; 3410c288874SVivek Goyal } 3420c288874SVivek Goyal 3430c288874SVivek Goyal void ovl_set_upperdata(struct inode *inode) 3440c288874SVivek Goyal { 3450c288874SVivek Goyal /* 3460c288874SVivek Goyal * Pairs with smp_rmb() in ovl_has_upperdata(). Make sure 3470c288874SVivek Goyal * if OVL_UPPERDATA flag is visible, then effects of write operations 3480c288874SVivek Goyal * before it are visible as well. 3490c288874SVivek Goyal */ 3500c288874SVivek Goyal smp_wmb(); 3510c288874SVivek Goyal ovl_set_flag(OVL_UPPERDATA, inode); 3520c288874SVivek Goyal } 3530c288874SVivek Goyal 3540c288874SVivek Goyal /* Caller should hold ovl_inode->lock */ 3550c288874SVivek Goyal bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags) 3560c288874SVivek Goyal { 3570c288874SVivek Goyal if (!ovl_open_flags_need_copy_up(flags)) 3580c288874SVivek Goyal return false; 3590c288874SVivek Goyal 3600c288874SVivek Goyal return !ovl_test_flag(OVL_UPPERDATA, d_inode(dentry)); 3610c288874SVivek Goyal } 3620c288874SVivek Goyal 3630c288874SVivek Goyal bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags) 3640c288874SVivek Goyal { 3650c288874SVivek Goyal if (!ovl_open_flags_need_copy_up(flags)) 3660c288874SVivek Goyal return false; 3670c288874SVivek Goyal 3680c288874SVivek Goyal return !ovl_has_upperdata(d_inode(dentry)); 3690c288874SVivek Goyal } 3700c288874SVivek Goyal 371a6c60655SMiklos Szeredi bool ovl_redirect_dir(struct super_block *sb) 372a6c60655SMiklos Szeredi { 373a6c60655SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 374a6c60655SMiklos Szeredi 37521a22878SAmir Goldstein return ofs->config.redirect_dir && !ofs->noxattr; 376a6c60655SMiklos Szeredi } 377a6c60655SMiklos Szeredi 378a6c60655SMiklos Szeredi const char *ovl_dentry_get_redirect(struct dentry *dentry) 379a6c60655SMiklos Szeredi { 380cf31c463SMiklos Szeredi return OVL_I(d_inode(dentry))->redirect; 381a6c60655SMiklos Szeredi } 382a6c60655SMiklos Szeredi 383a6c60655SMiklos Szeredi void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect) 384a6c60655SMiklos Szeredi { 385cf31c463SMiklos Szeredi struct ovl_inode *oi = OVL_I(d_inode(dentry)); 386a6c60655SMiklos Szeredi 387cf31c463SMiklos Szeredi kfree(oi->redirect); 388cf31c463SMiklos Szeredi oi->redirect = redirect; 389a6c60655SMiklos Szeredi } 390a6c60655SMiklos Szeredi 39109d8b586SMiklos Szeredi void ovl_inode_init(struct inode *inode, struct dentry *upperdentry, 3922664bd08SVivek Goyal struct dentry *lowerdentry, struct dentry *lowerdata) 393bbb1e54dSMiklos Szeredi { 394695b46e7SAmir Goldstein struct inode *realinode = d_inode(upperdentry ?: lowerdentry); 395695b46e7SAmir Goldstein 39609d8b586SMiklos Szeredi if (upperdentry) 39709d8b586SMiklos Szeredi OVL_I(inode)->__upperdentry = upperdentry; 39809d8b586SMiklos Szeredi if (lowerdentry) 39931747edaSAmir Goldstein OVL_I(inode)->lower = igrab(d_inode(lowerdentry)); 4002664bd08SVivek Goyal if (lowerdata) 4012664bd08SVivek Goyal OVL_I(inode)->lowerdata = igrab(d_inode(lowerdata)); 402bbb1e54dSMiklos Szeredi 403695b46e7SAmir Goldstein ovl_copyattr(realinode, inode); 4044f357295SMiklos Szeredi ovl_copyflags(realinode, inode); 405695b46e7SAmir Goldstein if (!inode->i_ino) 406695b46e7SAmir Goldstein inode->i_ino = realinode->i_ino; 407bbb1e54dSMiklos Szeredi } 408bbb1e54dSMiklos Szeredi 40909d8b586SMiklos Szeredi void ovl_inode_update(struct inode *inode, struct dentry *upperdentry) 410bbb1e54dSMiklos Szeredi { 41109d8b586SMiklos Szeredi struct inode *upperinode = d_inode(upperdentry); 412e6d2ebddSMiklos Szeredi 41309d8b586SMiklos Szeredi WARN_ON(OVL_I(inode)->__upperdentry); 41409d8b586SMiklos Szeredi 41525b7713aSMiklos Szeredi /* 41609d8b586SMiklos Szeredi * Make sure upperdentry is consistent before making it visible 41725b7713aSMiklos Szeredi */ 41825b7713aSMiklos Szeredi smp_wmb(); 41909d8b586SMiklos Szeredi OVL_I(inode)->__upperdentry = upperdentry; 42031747edaSAmir Goldstein if (inode_unhashed(inode)) { 421695b46e7SAmir Goldstein if (!inode->i_ino) 422695b46e7SAmir Goldstein inode->i_ino = upperinode->i_ino; 42325b7713aSMiklos Szeredi inode->i_private = upperinode; 424bbb1e54dSMiklos Szeredi __insert_inode_hash(inode, (unsigned long) upperinode); 425bbb1e54dSMiklos Szeredi } 42625b7713aSMiklos Szeredi } 427bbb1e54dSMiklos Szeredi 428d9854c87SMiklos Szeredi static void ovl_dentry_version_inc(struct dentry *dentry, bool impurity) 429bbb1e54dSMiklos Szeredi { 43004a01ac7SMiklos Szeredi struct inode *inode = d_inode(dentry); 431bbb1e54dSMiklos Szeredi 43204a01ac7SMiklos Szeredi WARN_ON(!inode_is_locked(inode)); 4334edb83bbSMiklos Szeredi /* 4344edb83bbSMiklos Szeredi * Version is used by readdir code to keep cache consistent. For merge 4354edb83bbSMiklos Szeredi * dirs all changes need to be noted. For non-merge dirs, cache only 4364edb83bbSMiklos Szeredi * contains impure (ones which have been copied up and have origins) 4374edb83bbSMiklos Szeredi * entries, so only need to note changes to impure entries. 4384edb83bbSMiklos Szeredi */ 4394edb83bbSMiklos Szeredi if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity) 44004a01ac7SMiklos Szeredi OVL_I(inode)->version++; 441bbb1e54dSMiklos Szeredi } 442bbb1e54dSMiklos Szeredi 443d9854c87SMiklos Szeredi void ovl_dir_modified(struct dentry *dentry, bool impurity) 444d9854c87SMiklos Szeredi { 445d9854c87SMiklos Szeredi /* Copy mtime/ctime */ 446d9854c87SMiklos Szeredi ovl_copyattr(d_inode(ovl_dentry_upper(dentry)), d_inode(dentry)); 447d9854c87SMiklos Szeredi 448d9854c87SMiklos Szeredi ovl_dentry_version_inc(dentry, impurity); 449d9854c87SMiklos Szeredi } 450d9854c87SMiklos Szeredi 451bbb1e54dSMiklos Szeredi u64 ovl_dentry_version_get(struct dentry *dentry) 452bbb1e54dSMiklos Szeredi { 45304a01ac7SMiklos Szeredi struct inode *inode = d_inode(dentry); 454bbb1e54dSMiklos Szeredi 45504a01ac7SMiklos Szeredi WARN_ON(!inode_is_locked(inode)); 45604a01ac7SMiklos Szeredi return OVL_I(inode)->version; 457bbb1e54dSMiklos Szeredi } 458bbb1e54dSMiklos Szeredi 459bbb1e54dSMiklos Szeredi bool ovl_is_whiteout(struct dentry *dentry) 460bbb1e54dSMiklos Szeredi { 461bbb1e54dSMiklos Szeredi struct inode *inode = dentry->d_inode; 462bbb1e54dSMiklos Szeredi 463bbb1e54dSMiklos Szeredi return inode && IS_WHITEOUT(inode); 464bbb1e54dSMiklos Szeredi } 465bbb1e54dSMiklos Szeredi 466bbb1e54dSMiklos Szeredi struct file *ovl_path_open(struct path *path, int flags) 467bbb1e54dSMiklos Szeredi { 468bbb1e54dSMiklos Szeredi return dentry_open(path, flags | O_NOATIME, current_cred()); 469bbb1e54dSMiklos Szeredi } 47039d3d60aSAmir Goldstein 4710c288874SVivek Goyal /* Caller should hold ovl_inode->lock */ 4720c288874SVivek Goyal static bool ovl_already_copied_up_locked(struct dentry *dentry, int flags) 4730c288874SVivek Goyal { 4740c288874SVivek Goyal bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; 4750c288874SVivek Goyal 4760c288874SVivek Goyal if (ovl_dentry_upper(dentry) && 4770c288874SVivek Goyal (ovl_dentry_has_upper_alias(dentry) || disconnected) && 4780c288874SVivek Goyal !ovl_dentry_needs_data_copy_up_locked(dentry, flags)) 4790c288874SVivek Goyal return true; 4800c288874SVivek Goyal 4810c288874SVivek Goyal return false; 4820c288874SVivek Goyal } 4830c288874SVivek Goyal 4840c288874SVivek Goyal bool ovl_already_copied_up(struct dentry *dentry, int flags) 4852002df85SVivek Goyal { 4862002df85SVivek Goyal bool disconnected = dentry->d_flags & DCACHE_DISCONNECTED; 4872002df85SVivek Goyal 4882002df85SVivek Goyal /* 4892002df85SVivek Goyal * Check if copy-up has happened as well as for upper alias (in 4902002df85SVivek Goyal * case of hard links) is there. 4912002df85SVivek Goyal * 4922002df85SVivek Goyal * Both checks are lockless: 4932002df85SVivek Goyal * - false negatives: will recheck under oi->lock 4942002df85SVivek Goyal * - false positives: 4952002df85SVivek Goyal * + ovl_dentry_upper() uses memory barriers to ensure the 4962002df85SVivek Goyal * upper dentry is up-to-date 4972002df85SVivek Goyal * + ovl_dentry_has_upper_alias() relies on locking of 4982002df85SVivek Goyal * upper parent i_rwsem to prevent reordering copy-up 4992002df85SVivek Goyal * with rename. 5002002df85SVivek Goyal */ 5012002df85SVivek Goyal if (ovl_dentry_upper(dentry) && 5020c288874SVivek Goyal (ovl_dentry_has_upper_alias(dentry) || disconnected) && 5030c288874SVivek Goyal !ovl_dentry_needs_data_copy_up(dentry, flags)) 5042002df85SVivek Goyal return true; 5052002df85SVivek Goyal 5062002df85SVivek Goyal return false; 5072002df85SVivek Goyal } 5082002df85SVivek Goyal 5090c288874SVivek Goyal int ovl_copy_up_start(struct dentry *dentry, int flags) 51039d3d60aSAmir Goldstein { 511a015dafcSAmir Goldstein struct ovl_inode *oi = OVL_I(d_inode(dentry)); 51239d3d60aSAmir Goldstein int err; 51339d3d60aSAmir Goldstein 514a015dafcSAmir Goldstein err = mutex_lock_interruptible(&oi->lock); 5150c288874SVivek Goyal if (!err && ovl_already_copied_up_locked(dentry, flags)) { 51639d3d60aSAmir Goldstein err = 1; /* Already copied up */ 517a015dafcSAmir Goldstein mutex_unlock(&oi->lock); 51839d3d60aSAmir Goldstein } 51939d3d60aSAmir Goldstein 52039d3d60aSAmir Goldstein return err; 52139d3d60aSAmir Goldstein } 52239d3d60aSAmir Goldstein 52339d3d60aSAmir Goldstein void ovl_copy_up_end(struct dentry *dentry) 52439d3d60aSAmir Goldstein { 525a015dafcSAmir Goldstein mutex_unlock(&OVL_I(d_inode(dentry))->lock); 52639d3d60aSAmir Goldstein } 52782b749b2SAmir Goldstein 528b79e05aaSAmir Goldstein bool ovl_check_origin_xattr(struct dentry *dentry) 529b79e05aaSAmir Goldstein { 530b79e05aaSAmir Goldstein int res; 531b79e05aaSAmir Goldstein 532b79e05aaSAmir Goldstein res = vfs_getxattr(dentry, OVL_XATTR_ORIGIN, NULL, 0); 533b79e05aaSAmir Goldstein 534b79e05aaSAmir Goldstein /* Zero size value means "copied up but origin unknown" */ 535b79e05aaSAmir Goldstein if (res >= 0) 536b79e05aaSAmir Goldstein return true; 537b79e05aaSAmir Goldstein 538b79e05aaSAmir Goldstein return false; 539b79e05aaSAmir Goldstein } 540b79e05aaSAmir Goldstein 541f3a15685SAmir Goldstein bool ovl_check_dir_xattr(struct dentry *dentry, const char *name) 542f3a15685SAmir Goldstein { 543f3a15685SAmir Goldstein int res; 544f3a15685SAmir Goldstein char val; 545f3a15685SAmir Goldstein 546f3a15685SAmir Goldstein if (!d_is_dir(dentry)) 547f3a15685SAmir Goldstein return false; 548f3a15685SAmir Goldstein 549f3a15685SAmir Goldstein res = vfs_getxattr(dentry, name, &val, 1); 550f3a15685SAmir Goldstein if (res == 1 && val == 'y') 551f3a15685SAmir Goldstein return true; 552f3a15685SAmir Goldstein 553f3a15685SAmir Goldstein return false; 554f3a15685SAmir Goldstein } 555f3a15685SAmir Goldstein 55682b749b2SAmir Goldstein int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, 55782b749b2SAmir Goldstein const char *name, const void *value, size_t size, 55882b749b2SAmir Goldstein int xerr) 55982b749b2SAmir Goldstein { 56082b749b2SAmir Goldstein int err; 56182b749b2SAmir Goldstein struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 56282b749b2SAmir Goldstein 56382b749b2SAmir Goldstein if (ofs->noxattr) 56482b749b2SAmir Goldstein return xerr; 56582b749b2SAmir Goldstein 56682b749b2SAmir Goldstein err = ovl_do_setxattr(upperdentry, name, value, size, 0); 56782b749b2SAmir Goldstein 56882b749b2SAmir Goldstein if (err == -EOPNOTSUPP) { 56982b749b2SAmir Goldstein pr_warn("overlayfs: cannot set %s xattr on upper\n", name); 57082b749b2SAmir Goldstein ofs->noxattr = true; 57182b749b2SAmir Goldstein return xerr; 57282b749b2SAmir Goldstein } 57382b749b2SAmir Goldstein 57482b749b2SAmir Goldstein return err; 57582b749b2SAmir Goldstein } 576f3a15685SAmir Goldstein 577f3a15685SAmir Goldstein int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry) 578f3a15685SAmir Goldstein { 579f3a15685SAmir Goldstein int err; 580f3a15685SAmir Goldstein 58113c72075SMiklos Szeredi if (ovl_test_flag(OVL_IMPURE, d_inode(dentry))) 582f3a15685SAmir Goldstein return 0; 583f3a15685SAmir Goldstein 584f3a15685SAmir Goldstein /* 585f3a15685SAmir Goldstein * Do not fail when upper doesn't support xattrs. 586f3a15685SAmir Goldstein * Upper inodes won't have origin nor redirect xattr anyway. 587f3a15685SAmir Goldstein */ 588f3a15685SAmir Goldstein err = ovl_check_setxattr(dentry, upperdentry, OVL_XATTR_IMPURE, 589f3a15685SAmir Goldstein "y", 1, 0); 590f3a15685SAmir Goldstein if (!err) 59113c72075SMiklos Szeredi ovl_set_flag(OVL_IMPURE, d_inode(dentry)); 592f3a15685SAmir Goldstein 593f3a15685SAmir Goldstein return err; 594f3a15685SAmir Goldstein } 59513c72075SMiklos Szeredi 59613c72075SMiklos Szeredi void ovl_set_flag(unsigned long flag, struct inode *inode) 59713c72075SMiklos Szeredi { 59813c72075SMiklos Szeredi set_bit(flag, &OVL_I(inode)->flags); 59913c72075SMiklos Szeredi } 60013c72075SMiklos Szeredi 6014edb83bbSMiklos Szeredi void ovl_clear_flag(unsigned long flag, struct inode *inode) 6024edb83bbSMiklos Szeredi { 6034edb83bbSMiklos Szeredi clear_bit(flag, &OVL_I(inode)->flags); 6044edb83bbSMiklos Szeredi } 6054edb83bbSMiklos Szeredi 60613c72075SMiklos Szeredi bool ovl_test_flag(unsigned long flag, struct inode *inode) 60713c72075SMiklos Szeredi { 60813c72075SMiklos Szeredi return test_bit(flag, &OVL_I(inode)->flags); 60913c72075SMiklos Szeredi } 610ad0af710SAmir Goldstein 611ad0af710SAmir Goldstein /** 612ad0af710SAmir Goldstein * Caller must hold a reference to inode to prevent it from being freed while 613ad0af710SAmir Goldstein * it is marked inuse. 614ad0af710SAmir Goldstein */ 615ad0af710SAmir Goldstein bool ovl_inuse_trylock(struct dentry *dentry) 616ad0af710SAmir Goldstein { 617ad0af710SAmir Goldstein struct inode *inode = d_inode(dentry); 618ad0af710SAmir Goldstein bool locked = false; 619ad0af710SAmir Goldstein 620ad0af710SAmir Goldstein spin_lock(&inode->i_lock); 621ad0af710SAmir Goldstein if (!(inode->i_state & I_OVL_INUSE)) { 622ad0af710SAmir Goldstein inode->i_state |= I_OVL_INUSE; 623ad0af710SAmir Goldstein locked = true; 624ad0af710SAmir Goldstein } 625ad0af710SAmir Goldstein spin_unlock(&inode->i_lock); 626ad0af710SAmir Goldstein 627ad0af710SAmir Goldstein return locked; 628ad0af710SAmir Goldstein } 629ad0af710SAmir Goldstein 630ad0af710SAmir Goldstein void ovl_inuse_unlock(struct dentry *dentry) 631ad0af710SAmir Goldstein { 632ad0af710SAmir Goldstein if (dentry) { 633ad0af710SAmir Goldstein struct inode *inode = d_inode(dentry); 634ad0af710SAmir Goldstein 635ad0af710SAmir Goldstein spin_lock(&inode->i_lock); 636ad0af710SAmir Goldstein WARN_ON(!(inode->i_state & I_OVL_INUSE)); 637ad0af710SAmir Goldstein inode->i_state &= ~I_OVL_INUSE; 638ad0af710SAmir Goldstein spin_unlock(&inode->i_lock); 639ad0af710SAmir Goldstein } 640ad0af710SAmir Goldstein } 6415f8415d6SAmir Goldstein 64224b33ee1SAmir Goldstein /* 64324b33ee1SAmir Goldstein * Does this overlay dentry need to be indexed on copy up? 64424b33ee1SAmir Goldstein */ 64524b33ee1SAmir Goldstein bool ovl_need_index(struct dentry *dentry) 64624b33ee1SAmir Goldstein { 64724b33ee1SAmir Goldstein struct dentry *lower = ovl_dentry_lower(dentry); 64824b33ee1SAmir Goldstein 64924b33ee1SAmir Goldstein if (!lower || !ovl_indexdir(dentry->d_sb)) 65024b33ee1SAmir Goldstein return false; 65124b33ee1SAmir Goldstein 652fbd2d207SAmir Goldstein /* Index all files for NFS export and consistency verification */ 653016b720fSAmir Goldstein if (ovl_index_all(dentry->d_sb)) 654fbd2d207SAmir Goldstein return true; 655fbd2d207SAmir Goldstein 65624b33ee1SAmir Goldstein /* Index only lower hardlinks on copy up */ 65724b33ee1SAmir Goldstein if (!d_is_dir(lower) && d_inode(lower)->i_nlink > 1) 65824b33ee1SAmir Goldstein return true; 65924b33ee1SAmir Goldstein 66024b33ee1SAmir Goldstein return false; 66124b33ee1SAmir Goldstein } 66224b33ee1SAmir Goldstein 6639f4ec904SAmir Goldstein /* Caller must hold OVL_I(inode)->lock */ 664caf70cb2SAmir Goldstein static void ovl_cleanup_index(struct dentry *dentry) 665caf70cb2SAmir Goldstein { 666e7dd0e71SAmir Goldstein struct dentry *indexdir = ovl_indexdir(dentry->d_sb); 667e7dd0e71SAmir Goldstein struct inode *dir = indexdir->d_inode; 668caf70cb2SAmir Goldstein struct dentry *lowerdentry = ovl_dentry_lower(dentry); 669caf70cb2SAmir Goldstein struct dentry *upperdentry = ovl_dentry_upper(dentry); 670caf70cb2SAmir Goldstein struct dentry *index = NULL; 671caf70cb2SAmir Goldstein struct inode *inode; 672caf70cb2SAmir Goldstein struct qstr name; 673caf70cb2SAmir Goldstein int err; 674caf70cb2SAmir Goldstein 675caf70cb2SAmir Goldstein err = ovl_get_index_name(lowerdentry, &name); 676caf70cb2SAmir Goldstein if (err) 677caf70cb2SAmir Goldstein goto fail; 678caf70cb2SAmir Goldstein 679caf70cb2SAmir Goldstein inode = d_inode(upperdentry); 68089a17556SAmir Goldstein if (!S_ISDIR(inode->i_mode) && inode->i_nlink != 1) { 681caf70cb2SAmir Goldstein pr_warn_ratelimited("overlayfs: cleanup linked index (%pd2, ino=%lu, nlink=%u)\n", 682caf70cb2SAmir Goldstein upperdentry, inode->i_ino, inode->i_nlink); 683caf70cb2SAmir Goldstein /* 684caf70cb2SAmir Goldstein * We either have a bug with persistent union nlink or a lower 685caf70cb2SAmir Goldstein * hardlink was added while overlay is mounted. Adding a lower 686caf70cb2SAmir Goldstein * hardlink and then unlinking all overlay hardlinks would drop 687caf70cb2SAmir Goldstein * overlay nlink to zero before all upper inodes are unlinked. 688caf70cb2SAmir Goldstein * As a safety measure, when that situation is detected, set 689caf70cb2SAmir Goldstein * the overlay nlink to the index inode nlink minus one for the 690caf70cb2SAmir Goldstein * index entry itself. 691caf70cb2SAmir Goldstein */ 692caf70cb2SAmir Goldstein set_nlink(d_inode(dentry), inode->i_nlink - 1); 693caf70cb2SAmir Goldstein ovl_set_nlink_upper(dentry); 694caf70cb2SAmir Goldstein goto out; 695caf70cb2SAmir Goldstein } 696caf70cb2SAmir Goldstein 697caf70cb2SAmir Goldstein inode_lock_nested(dir, I_MUTEX_PARENT); 698e7dd0e71SAmir Goldstein index = lookup_one_len(name.name, indexdir, name.len); 699caf70cb2SAmir Goldstein err = PTR_ERR(index); 700e7dd0e71SAmir Goldstein if (IS_ERR(index)) { 7019f4ec904SAmir Goldstein index = NULL; 702e7dd0e71SAmir Goldstein } else if (ovl_index_all(dentry->d_sb)) { 703e7dd0e71SAmir Goldstein /* Whiteout orphan index to block future open by handle */ 704e7dd0e71SAmir Goldstein err = ovl_cleanup_and_whiteout(indexdir, dir, index); 705e7dd0e71SAmir Goldstein } else { 706e7dd0e71SAmir Goldstein /* Cleanup orphan index entries */ 707e7dd0e71SAmir Goldstein err = ovl_cleanup(dir, index); 708e7dd0e71SAmir Goldstein } 7099f4ec904SAmir Goldstein 710caf70cb2SAmir Goldstein inode_unlock(dir); 711caf70cb2SAmir Goldstein if (err) 712caf70cb2SAmir Goldstein goto fail; 713caf70cb2SAmir Goldstein 714caf70cb2SAmir Goldstein out: 715caf70cb2SAmir Goldstein dput(index); 716caf70cb2SAmir Goldstein return; 717caf70cb2SAmir Goldstein 718caf70cb2SAmir Goldstein fail: 719caf70cb2SAmir Goldstein pr_err("overlayfs: cleanup index of '%pd2' failed (%i)\n", dentry, err); 720caf70cb2SAmir Goldstein goto out; 721caf70cb2SAmir Goldstein } 722caf70cb2SAmir Goldstein 7235f8415d6SAmir Goldstein /* 7245f8415d6SAmir Goldstein * Operations that change overlay inode and upper inode nlink need to be 7255f8415d6SAmir Goldstein * synchronized with copy up for persistent nlink accounting. 7265f8415d6SAmir Goldstein */ 7275f8415d6SAmir Goldstein int ovl_nlink_start(struct dentry *dentry, bool *locked) 7285f8415d6SAmir Goldstein { 7295f8415d6SAmir Goldstein struct ovl_inode *oi = OVL_I(d_inode(dentry)); 7305f8415d6SAmir Goldstein const struct cred *old_cred; 7315f8415d6SAmir Goldstein int err; 7325f8415d6SAmir Goldstein 73389a17556SAmir Goldstein if (!d_inode(dentry)) 7345f8415d6SAmir Goldstein return 0; 7355f8415d6SAmir Goldstein 7365f8415d6SAmir Goldstein /* 7375f8415d6SAmir Goldstein * With inodes index is enabled, we store the union overlay nlink 73824b33ee1SAmir Goldstein * in an xattr on the index inode. When whiting out an indexed lower, 7395f8415d6SAmir Goldstein * we need to decrement the overlay persistent nlink, but before the 7405f8415d6SAmir Goldstein * first copy up, we have no upper index inode to store the xattr. 7415f8415d6SAmir Goldstein * 74224b33ee1SAmir Goldstein * As a workaround, before whiteout/rename over an indexed lower, 7435f8415d6SAmir Goldstein * copy up to create the upper index. Creating the upper index will 7445f8415d6SAmir Goldstein * initialize the overlay nlink, so it could be dropped if unlink 7455f8415d6SAmir Goldstein * or rename succeeds. 7465f8415d6SAmir Goldstein * 7475f8415d6SAmir Goldstein * TODO: implement metadata only index copy up when called with 7485f8415d6SAmir Goldstein * ovl_copy_up_flags(dentry, O_PATH). 7495f8415d6SAmir Goldstein */ 75024b33ee1SAmir Goldstein if (ovl_need_index(dentry) && !ovl_dentry_has_upper_alias(dentry)) { 7515f8415d6SAmir Goldstein err = ovl_copy_up(dentry); 7525f8415d6SAmir Goldstein if (err) 7535f8415d6SAmir Goldstein return err; 7545f8415d6SAmir Goldstein } 7555f8415d6SAmir Goldstein 7565f8415d6SAmir Goldstein err = mutex_lock_interruptible(&oi->lock); 7575f8415d6SAmir Goldstein if (err) 7585f8415d6SAmir Goldstein return err; 7595f8415d6SAmir Goldstein 76089a17556SAmir Goldstein if (d_is_dir(dentry) || !ovl_test_flag(OVL_INDEX, d_inode(dentry))) 7615f8415d6SAmir Goldstein goto out; 7625f8415d6SAmir Goldstein 7635f8415d6SAmir Goldstein old_cred = ovl_override_creds(dentry->d_sb); 7645f8415d6SAmir Goldstein /* 7655f8415d6SAmir Goldstein * The overlay inode nlink should be incremented/decremented IFF the 7665f8415d6SAmir Goldstein * upper operation succeeds, along with nlink change of upper inode. 7675f8415d6SAmir Goldstein * Therefore, before link/unlink/rename, we store the union nlink 7685f8415d6SAmir Goldstein * value relative to the upper inode nlink in an upper inode xattr. 7695f8415d6SAmir Goldstein */ 7705f8415d6SAmir Goldstein err = ovl_set_nlink_upper(dentry); 7715f8415d6SAmir Goldstein revert_creds(old_cred); 7725f8415d6SAmir Goldstein 7735f8415d6SAmir Goldstein out: 7745f8415d6SAmir Goldstein if (err) 7755f8415d6SAmir Goldstein mutex_unlock(&oi->lock); 7765f8415d6SAmir Goldstein else 7775f8415d6SAmir Goldstein *locked = true; 7785f8415d6SAmir Goldstein 7795f8415d6SAmir Goldstein return err; 7805f8415d6SAmir Goldstein } 7815f8415d6SAmir Goldstein 7825f8415d6SAmir Goldstein void ovl_nlink_end(struct dentry *dentry, bool locked) 7835f8415d6SAmir Goldstein { 784caf70cb2SAmir Goldstein if (locked) { 785caf70cb2SAmir Goldstein if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) && 786caf70cb2SAmir Goldstein d_inode(dentry)->i_nlink == 0) { 787caf70cb2SAmir Goldstein const struct cred *old_cred; 788caf70cb2SAmir Goldstein 789caf70cb2SAmir Goldstein old_cred = ovl_override_creds(dentry->d_sb); 790caf70cb2SAmir Goldstein ovl_cleanup_index(dentry); 791caf70cb2SAmir Goldstein revert_creds(old_cred); 792caf70cb2SAmir Goldstein } 793caf70cb2SAmir Goldstein 7945f8415d6SAmir Goldstein mutex_unlock(&OVL_I(d_inode(dentry))->lock); 7955f8415d6SAmir Goldstein } 796caf70cb2SAmir Goldstein } 7975820dc08SAmir Goldstein 7985820dc08SAmir Goldstein int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir) 7995820dc08SAmir Goldstein { 8005820dc08SAmir Goldstein /* Workdir should not be the same as upperdir */ 8015820dc08SAmir Goldstein if (workdir == upperdir) 8025820dc08SAmir Goldstein goto err; 8035820dc08SAmir Goldstein 8045820dc08SAmir Goldstein /* Workdir should not be subdir of upperdir and vice versa */ 8055820dc08SAmir Goldstein if (lock_rename(workdir, upperdir) != NULL) 8065820dc08SAmir Goldstein goto err_unlock; 8075820dc08SAmir Goldstein 8085820dc08SAmir Goldstein return 0; 8095820dc08SAmir Goldstein 8105820dc08SAmir Goldstein err_unlock: 8115820dc08SAmir Goldstein unlock_rename(workdir, upperdir); 8125820dc08SAmir Goldstein err: 8135820dc08SAmir Goldstein pr_err("overlayfs: failed to lock workdir+upperdir\n"); 8145820dc08SAmir Goldstein return -EIO; 8155820dc08SAmir Goldstein } 8169d3dfea3SVivek Goyal 8179d3dfea3SVivek Goyal /* err < 0, 0 if no metacopy xattr, 1 if metacopy xattr found */ 8189d3dfea3SVivek Goyal int ovl_check_metacopy_xattr(struct dentry *dentry) 8199d3dfea3SVivek Goyal { 8209d3dfea3SVivek Goyal int res; 8219d3dfea3SVivek Goyal 8229d3dfea3SVivek Goyal /* Only regular files can have metacopy xattr */ 8239d3dfea3SVivek Goyal if (!S_ISREG(d_inode(dentry)->i_mode)) 8249d3dfea3SVivek Goyal return 0; 8259d3dfea3SVivek Goyal 8269d3dfea3SVivek Goyal res = vfs_getxattr(dentry, OVL_XATTR_METACOPY, NULL, 0); 8279d3dfea3SVivek Goyal if (res < 0) { 8289d3dfea3SVivek Goyal if (res == -ENODATA || res == -EOPNOTSUPP) 8299d3dfea3SVivek Goyal return 0; 8309d3dfea3SVivek Goyal goto out; 8319d3dfea3SVivek Goyal } 8329d3dfea3SVivek Goyal 8339d3dfea3SVivek Goyal return 1; 8349d3dfea3SVivek Goyal out: 8359d3dfea3SVivek Goyal pr_warn_ratelimited("overlayfs: failed to get metacopy (%i)\n", res); 8369d3dfea3SVivek Goyal return res; 8379d3dfea3SVivek Goyal } 83867d756c2SVivek Goyal 83967d756c2SVivek Goyal bool ovl_is_metacopy_dentry(struct dentry *dentry) 84067d756c2SVivek Goyal { 84167d756c2SVivek Goyal struct ovl_entry *oe = dentry->d_fsdata; 84267d756c2SVivek Goyal 84367d756c2SVivek Goyal if (!d_is_reg(dentry)) 84467d756c2SVivek Goyal return false; 84567d756c2SVivek Goyal 84667d756c2SVivek Goyal if (ovl_dentry_upper(dentry)) { 84767d756c2SVivek Goyal if (!ovl_has_upperdata(d_inode(dentry))) 84867d756c2SVivek Goyal return true; 84967d756c2SVivek Goyal return false; 85067d756c2SVivek Goyal } 85167d756c2SVivek Goyal 85267d756c2SVivek Goyal return (oe->numlower > 1); 85367d756c2SVivek Goyal } 854