1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2e9be9d5eSMiklos Szeredi /* 3e9be9d5eSMiklos Szeredi * 4e9be9d5eSMiklos Szeredi * Copyright (C) 2011 Novell Inc. 5e9be9d5eSMiklos Szeredi */ 6e9be9d5eSMiklos Szeredi 75b825c3aSIngo Molnar #include <uapi/linux/magic.h> 8e9be9d5eSMiklos Szeredi #include <linux/fs.h> 9e9be9d5eSMiklos Szeredi #include <linux/namei.h> 10e9be9d5eSMiklos Szeredi #include <linux/xattr.h> 11e9be9d5eSMiklos Szeredi #include <linux/mount.h> 12e9be9d5eSMiklos Szeredi #include <linux/parser.h> 13e9be9d5eSMiklos Szeredi #include <linux/module.h> 14cc259639SAndy Whitcroft #include <linux/statfs.h> 15f45827e8SErez Zadok #include <linux/seq_file.h> 16d837a49bSMiklos Szeredi #include <linux/posix_acl_xattr.h> 17e487d889SAmir Goldstein #include <linux/exportfs.h> 182b1a7746SMiklos Szeredi #include <linux/file.h> 19e9be9d5eSMiklos Szeredi #include "overlayfs.h" 20e9be9d5eSMiklos Szeredi 21e9be9d5eSMiklos Szeredi MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 22e9be9d5eSMiklos Szeredi MODULE_DESCRIPTION("Overlay filesystem"); 23e9be9d5eSMiklos Szeredi MODULE_LICENSE("GPL"); 24e9be9d5eSMiklos Szeredi 25e9be9d5eSMiklos Szeredi 26e9be9d5eSMiklos Szeredi struct ovl_dir_cache; 27e9be9d5eSMiklos Szeredi 28a78d9f0dSMiklos Szeredi #define OVL_MAX_STACK 500 29a78d9f0dSMiklos Szeredi 30688ea0e5SMiklos Szeredi static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); 31688ea0e5SMiklos Szeredi module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); 32253e7483SNicolas Schier MODULE_PARM_DESC(redirect_dir, 33688ea0e5SMiklos Szeredi "Default to on or off for the redirect_dir feature"); 34e9be9d5eSMiklos Szeredi 35438c84c2SMiklos Szeredi static bool ovl_redirect_always_follow = 36438c84c2SMiklos Szeredi IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); 37438c84c2SMiklos Szeredi module_param_named(redirect_always_follow, ovl_redirect_always_follow, 38438c84c2SMiklos Szeredi bool, 0644); 39253e7483SNicolas Schier MODULE_PARM_DESC(redirect_always_follow, 40438c84c2SMiklos Szeredi "Follow redirects even if redirect_dir feature is turned off"); 41438c84c2SMiklos Szeredi 4202bcd157SAmir Goldstein static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); 4302bcd157SAmir Goldstein module_param_named(index, ovl_index_def, bool, 0644); 44253e7483SNicolas Schier MODULE_PARM_DESC(index, 4502bcd157SAmir Goldstein "Default to on or off for the inodes index feature"); 4602bcd157SAmir Goldstein 47f168f109SAmir Goldstein static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); 48f168f109SAmir Goldstein module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); 49253e7483SNicolas Schier MODULE_PARM_DESC(nfs_export, 50f168f109SAmir Goldstein "Default to on or off for the NFS export feature"); 51f168f109SAmir Goldstein 52795939a9SAmir Goldstein static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); 53795939a9SAmir Goldstein module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); 54253e7483SNicolas Schier MODULE_PARM_DESC(xino_auto, 55795939a9SAmir Goldstein "Auto enable xino feature"); 56795939a9SAmir Goldstein 574155c10aSMiklos Szeredi static void ovl_entry_stack_free(struct ovl_entry *oe) 584155c10aSMiklos Szeredi { 59*5522c9c7SAmir Goldstein struct ovl_path *lowerstack = ovl_lowerstack(oe); 604155c10aSMiklos Szeredi unsigned int i; 614155c10aSMiklos Szeredi 62*5522c9c7SAmir Goldstein for (i = 0; i < ovl_numlower(oe); i++) 63*5522c9c7SAmir Goldstein dput(lowerstack[i].dentry); 644155c10aSMiklos Szeredi } 654155c10aSMiklos Szeredi 66d5791044SVivek Goyal static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); 67d5791044SVivek Goyal module_param_named(metacopy, ovl_metacopy_def, bool, 0644); 68253e7483SNicolas Schier MODULE_PARM_DESC(metacopy, 69d5791044SVivek Goyal "Default to on or off for the metadata only copy up feature"); 70d5791044SVivek Goyal 71e9be9d5eSMiklos Szeredi static void ovl_dentry_release(struct dentry *dentry) 72e9be9d5eSMiklos Szeredi { 73e9be9d5eSMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 74e9be9d5eSMiklos Szeredi 75e9be9d5eSMiklos Szeredi if (oe) { 764155c10aSMiklos Szeredi ovl_entry_stack_free(oe); 77e9be9d5eSMiklos Szeredi kfree_rcu(oe, rcu); 78e9be9d5eSMiklos Szeredi } 79e9be9d5eSMiklos Szeredi } 80e9be9d5eSMiklos Szeredi 812d902671SMiklos Szeredi static struct dentry *ovl_d_real(struct dentry *dentry, 82fb16043bSMiklos Szeredi const struct inode *inode) 83d101a125SMiklos Szeredi { 84cef4cbffSMiklos Szeredi struct dentry *real = NULL, *lower; 85d101a125SMiklos Szeredi 86e8c985baSMiklos Szeredi /* It's an overlay file */ 87e8c985baSMiklos Szeredi if (inode && d_inode(dentry) == inode) 88e8c985baSMiklos Szeredi return dentry; 89e8c985baSMiklos Szeredi 90ca4c8a3aSMiklos Szeredi if (!d_is_reg(dentry)) { 91d101a125SMiklos Szeredi if (!inode || inode == d_inode(dentry)) 92d101a125SMiklos Szeredi return dentry; 93d101a125SMiklos Szeredi goto bug; 94d101a125SMiklos Szeredi } 95d101a125SMiklos Szeredi 96d101a125SMiklos Szeredi real = ovl_dentry_upper(dentry); 972c3d7358SVivek Goyal if (real && (inode == d_inode(real))) 98d101a125SMiklos Szeredi return real; 99d101a125SMiklos Szeredi 1002c3d7358SVivek Goyal if (real && !inode && ovl_has_upperdata(d_inode(dentry))) 1012c3d7358SVivek Goyal return real; 1022c3d7358SVivek Goyal 103cef4cbffSMiklos Szeredi lower = ovl_dentry_lowerdata(dentry); 104cef4cbffSMiklos Szeredi if (!lower) 105d101a125SMiklos Szeredi goto bug; 106cef4cbffSMiklos Szeredi real = lower; 107d101a125SMiklos Szeredi 108c4fcfc16SMiklos Szeredi /* Handle recursion */ 109fb16043bSMiklos Szeredi real = d_real(real, inode); 110c4fcfc16SMiklos Szeredi 111d101a125SMiklos Szeredi if (!inode || inode == d_inode(real)) 112d101a125SMiklos Szeredi return real; 113d101a125SMiklos Szeredi bug: 114cef4cbffSMiklos Szeredi WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", 115cef4cbffSMiklos Szeredi __func__, dentry, inode ? inode->i_sb->s_id : "NULL", 116cef4cbffSMiklos Szeredi inode ? inode->i_ino : 0, real, 117cef4cbffSMiklos Szeredi real && d_inode(real) ? d_inode(real)->i_ino : 0); 118d101a125SMiklos Szeredi return dentry; 119d101a125SMiklos Szeredi } 120d101a125SMiklos Szeredi 1213bb7df92SMiklos Szeredi static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) 1223bb7df92SMiklos Szeredi { 1233bb7df92SMiklos Szeredi int ret = 1; 1243bb7df92SMiklos Szeredi 1253bb7df92SMiklos Szeredi if (weak) { 1263bb7df92SMiklos Szeredi if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) 1273bb7df92SMiklos Szeredi ret = d->d_op->d_weak_revalidate(d, flags); 1283bb7df92SMiklos Szeredi } else if (d->d_flags & DCACHE_OP_REVALIDATE) { 1293bb7df92SMiklos Szeredi ret = d->d_op->d_revalidate(d, flags); 1303bb7df92SMiklos Szeredi if (!ret) { 1313bb7df92SMiklos Szeredi if (!(flags & LOOKUP_RCU)) 1323bb7df92SMiklos Szeredi d_invalidate(d); 1333bb7df92SMiklos Szeredi ret = -ESTALE; 1343bb7df92SMiklos Szeredi } 1353bb7df92SMiklos Szeredi } 1363bb7df92SMiklos Szeredi return ret; 1373bb7df92SMiklos Szeredi } 1383bb7df92SMiklos Szeredi 1393bb7df92SMiklos Szeredi static int ovl_dentry_revalidate_common(struct dentry *dentry, 1403bb7df92SMiklos Szeredi unsigned int flags, bool weak) 1417c03b5d4SMiklos Szeredi { 142a6ff2bc0SAmir Goldstein struct ovl_entry *oe = OVL_E(dentry); 143*5522c9c7SAmir Goldstein struct ovl_path *lowerstack = ovl_lowerstack(oe); 144672e4268SChen Zhongjin struct inode *inode = d_inode_rcu(dentry); 145bccece1eSMiklos Szeredi struct dentry *upper; 1467c03b5d4SMiklos Szeredi unsigned int i; 1477c03b5d4SMiklos Szeredi int ret = 1; 1487c03b5d4SMiklos Szeredi 149672e4268SChen Zhongjin /* Careful in RCU mode */ 150672e4268SChen Zhongjin if (!inode) 151672e4268SChen Zhongjin return -ECHILD; 152672e4268SChen Zhongjin 153672e4268SChen Zhongjin upper = ovl_i_dentry_upper(inode); 154bccece1eSMiklos Szeredi if (upper) 155bccece1eSMiklos Szeredi ret = ovl_revalidate_real(upper, flags, weak); 156bccece1eSMiklos Szeredi 157*5522c9c7SAmir Goldstein for (i = 0; ret > 0 && i < ovl_numlower(oe); i++) 158*5522c9c7SAmir Goldstein ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak); 159*5522c9c7SAmir Goldstein 1607c03b5d4SMiklos Szeredi return ret; 1617c03b5d4SMiklos Szeredi } 1623bb7df92SMiklos Szeredi 1633bb7df92SMiklos Szeredi static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) 1643bb7df92SMiklos Szeredi { 1653bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, false); 1667c03b5d4SMiklos Szeredi } 1677c03b5d4SMiklos Szeredi 1687c03b5d4SMiklos Szeredi static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) 1697c03b5d4SMiklos Szeredi { 1703bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, true); 1717c03b5d4SMiklos Szeredi } 1727c03b5d4SMiklos Szeredi 173e9be9d5eSMiklos Szeredi static const struct dentry_operations ovl_dentry_operations = { 174e9be9d5eSMiklos Szeredi .d_release = ovl_dentry_release, 175d101a125SMiklos Szeredi .d_real = ovl_d_real, 1767c03b5d4SMiklos Szeredi .d_revalidate = ovl_dentry_revalidate, 1777c03b5d4SMiklos Szeredi .d_weak_revalidate = ovl_dentry_weak_revalidate, 1787c03b5d4SMiklos Szeredi }; 1797c03b5d4SMiklos Szeredi 18013cf199dSAmir Goldstein static struct kmem_cache *ovl_inode_cachep; 18113cf199dSAmir Goldstein 18213cf199dSAmir Goldstein static struct inode *ovl_alloc_inode(struct super_block *sb) 18313cf199dSAmir Goldstein { 184fd60b288SMuchun Song struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); 18513cf199dSAmir Goldstein 186b3885bd6SHirofumi Nakagawa if (!oi) 187b3885bd6SHirofumi Nakagawa return NULL; 188b3885bd6SHirofumi Nakagawa 18904a01ac7SMiklos Szeredi oi->cache = NULL; 190cf31c463SMiklos Szeredi oi->redirect = NULL; 19104a01ac7SMiklos Szeredi oi->version = 0; 19213c72075SMiklos Szeredi oi->flags = 0; 19309d8b586SMiklos Szeredi oi->__upperdentry = NULL; 194ffa5723cSAmir Goldstein oi->lowerpath.dentry = NULL; 195ffa5723cSAmir Goldstein oi->lowerpath.layer = NULL; 1962664bd08SVivek Goyal oi->lowerdata = NULL; 197a015dafcSAmir Goldstein mutex_init(&oi->lock); 19825b7713aSMiklos Szeredi 19913cf199dSAmir Goldstein return &oi->vfs_inode; 20013cf199dSAmir Goldstein } 20113cf199dSAmir Goldstein 2020b269dedSAl Viro static void ovl_free_inode(struct inode *inode) 20313cf199dSAmir Goldstein { 2040b269dedSAl Viro struct ovl_inode *oi = OVL_I(inode); 20513cf199dSAmir Goldstein 2060b269dedSAl Viro kfree(oi->redirect); 2070b269dedSAl Viro mutex_destroy(&oi->lock); 2080b269dedSAl Viro kmem_cache_free(ovl_inode_cachep, oi); 20913cf199dSAmir Goldstein } 21013cf199dSAmir Goldstein 21113cf199dSAmir Goldstein static void ovl_destroy_inode(struct inode *inode) 21213cf199dSAmir Goldstein { 21309d8b586SMiklos Szeredi struct ovl_inode *oi = OVL_I(inode); 21409d8b586SMiklos Szeredi 21509d8b586SMiklos Szeredi dput(oi->__upperdentry); 216ffa5723cSAmir Goldstein dput(oi->lowerpath.dentry); 2172664bd08SVivek Goyal if (S_ISDIR(inode->i_mode)) 2184edb83bbSMiklos Szeredi ovl_dir_cache_free(inode); 2192664bd08SVivek Goyal else 2202664bd08SVivek Goyal iput(oi->lowerdata); 22113cf199dSAmir Goldstein } 22213cf199dSAmir Goldstein 223ad204488SMiklos Szeredi static void ovl_free_fs(struct ovl_fs *ofs) 224e9be9d5eSMiklos Szeredi { 225df820f8dSMiklos Szeredi struct vfsmount **mounts; 226dd662667SMiklos Szeredi unsigned i; 227e9be9d5eSMiklos Szeredi 2280be0bfd2SAmir Goldstein iput(ofs->workbasedir_trap); 229146d62e5SAmir Goldstein iput(ofs->indexdir_trap); 230146d62e5SAmir Goldstein iput(ofs->workdir_trap); 231c21c839bSChengguang Xu dput(ofs->whiteout); 232ad204488SMiklos Szeredi dput(ofs->indexdir); 233ad204488SMiklos Szeredi dput(ofs->workdir); 234ad204488SMiklos Szeredi if (ofs->workdir_locked) 235ad204488SMiklos Szeredi ovl_inuse_unlock(ofs->workbasedir); 236ad204488SMiklos Szeredi dput(ofs->workbasedir); 237ad204488SMiklos Szeredi if (ofs->upperdir_locked) 23808f4c7c8SMiklos Szeredi ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); 239df820f8dSMiklos Szeredi 240df820f8dSMiklos Szeredi /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ 241df820f8dSMiklos Szeredi mounts = (struct vfsmount **) ofs->layers; 242b8e42a65SMiklos Szeredi for (i = 0; i < ofs->numlayer; i++) { 24394375f9dSAmir Goldstein iput(ofs->layers[i].trap); 244df820f8dSMiklos Szeredi mounts[i] = ofs->layers[i].mnt; 245146d62e5SAmir Goldstein } 246df820f8dSMiklos Szeredi kern_unmount_array(mounts, ofs->numlayer); 24794375f9dSAmir Goldstein kfree(ofs->layers); 248b7bf9908SAmir Goldstein for (i = 0; i < ofs->numfs; i++) 24907f1e596SAmir Goldstein free_anon_bdev(ofs->fs[i].pseudo_dev); 25007f1e596SAmir Goldstein kfree(ofs->fs); 251e9be9d5eSMiklos Szeredi 252ad204488SMiklos Szeredi kfree(ofs->config.lowerdir); 253ad204488SMiklos Szeredi kfree(ofs->config.upperdir); 254ad204488SMiklos Szeredi kfree(ofs->config.workdir); 255438c84c2SMiklos Szeredi kfree(ofs->config.redirect_mode); 256ad204488SMiklos Szeredi if (ofs->creator_cred) 257ad204488SMiklos Szeredi put_cred(ofs->creator_cred); 258ad204488SMiklos Szeredi kfree(ofs); 259e9be9d5eSMiklos Szeredi } 260e9be9d5eSMiklos Szeredi 261a9075cdbSMiklos Szeredi static void ovl_put_super(struct super_block *sb) 262a9075cdbSMiklos Szeredi { 263a9075cdbSMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 264a9075cdbSMiklos Szeredi 265a9075cdbSMiklos Szeredi ovl_free_fs(ofs); 266a9075cdbSMiklos Szeredi } 267a9075cdbSMiklos Szeredi 268e8d4bfe3SChengguang Xu /* Sync real dirty inodes in upper filesystem (if it exists) */ 269e593b2bfSAmir Goldstein static int ovl_sync_fs(struct super_block *sb, int wait) 270e593b2bfSAmir Goldstein { 271ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 272e593b2bfSAmir Goldstein struct super_block *upper_sb; 273e593b2bfSAmir Goldstein int ret; 274e593b2bfSAmir Goldstein 275335d3fc5SSargun Dhillon ret = ovl_sync_status(ofs); 276335d3fc5SSargun Dhillon /* 277335d3fc5SSargun Dhillon * We have to always set the err, because the return value isn't 278335d3fc5SSargun Dhillon * checked in syncfs, and instead indirectly return an error via 279335d3fc5SSargun Dhillon * the sb's writeback errseq, which VFS inspects after this call. 280335d3fc5SSargun Dhillon */ 281335d3fc5SSargun Dhillon if (ret < 0) { 282335d3fc5SSargun Dhillon errseq_set(&sb->s_wb_err, -EIO); 283335d3fc5SSargun Dhillon return -EIO; 284335d3fc5SSargun Dhillon } 285e8d4bfe3SChengguang Xu 286335d3fc5SSargun Dhillon if (!ret) 287335d3fc5SSargun Dhillon return ret; 288335d3fc5SSargun Dhillon 289e8d4bfe3SChengguang Xu /* 29032b1924bSKonstantin Khlebnikov * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). 29132b1924bSKonstantin Khlebnikov * All the super blocks will be iterated, including upper_sb. 292e8d4bfe3SChengguang Xu * 293e8d4bfe3SChengguang Xu * If this is a syncfs(2) call, then we do need to call 294e8d4bfe3SChengguang Xu * sync_filesystem() on upper_sb, but enough if we do it when being 295e8d4bfe3SChengguang Xu * called with wait == 1. 296e8d4bfe3SChengguang Xu */ 297e8d4bfe3SChengguang Xu if (!wait) 298e593b2bfSAmir Goldstein return 0; 299e593b2bfSAmir Goldstein 30008f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 301e8d4bfe3SChengguang Xu 302e593b2bfSAmir Goldstein down_read(&upper_sb->s_umount); 303e8d4bfe3SChengguang Xu ret = sync_filesystem(upper_sb); 304e593b2bfSAmir Goldstein up_read(&upper_sb->s_umount); 305e8d4bfe3SChengguang Xu 306e593b2bfSAmir Goldstein return ret; 307e593b2bfSAmir Goldstein } 308e593b2bfSAmir Goldstein 309cc259639SAndy Whitcroft /** 310cc259639SAndy Whitcroft * ovl_statfs 3119c5dd803SYang Li * @dentry: The dentry to query 312cc259639SAndy Whitcroft * @buf: The struct kstatfs to fill in with stats 313cc259639SAndy Whitcroft * 314cc259639SAndy Whitcroft * Get the filesystem statistics. As writes always target the upper layer 3154ebc5818SMiklos Szeredi * filesystem pass the statfs to the upper filesystem (if it exists) 316cc259639SAndy Whitcroft */ 317cc259639SAndy Whitcroft static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) 318cc259639SAndy Whitcroft { 319cc259639SAndy Whitcroft struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 320cc259639SAndy Whitcroft struct dentry *root_dentry = dentry->d_sb->s_root; 321cc259639SAndy Whitcroft struct path path; 322cc259639SAndy Whitcroft int err; 323cc259639SAndy Whitcroft 3244ebc5818SMiklos Szeredi ovl_path_real(root_dentry, &path); 325cc259639SAndy Whitcroft 326cc259639SAndy Whitcroft err = vfs_statfs(&path, buf); 327cc259639SAndy Whitcroft if (!err) { 3286b2d5fe4SMiklos Szeredi buf->f_namelen = ofs->namelen; 329cc259639SAndy Whitcroft buf->f_type = OVERLAYFS_SUPER_MAGIC; 330cc259639SAndy Whitcroft } 331cc259639SAndy Whitcroft 332cc259639SAndy Whitcroft return err; 333cc259639SAndy Whitcroft } 334cc259639SAndy Whitcroft 33502bcd157SAmir Goldstein /* Will this overlay be forced to mount/remount ro? */ 336ad204488SMiklos Szeredi static bool ovl_force_readonly(struct ovl_fs *ofs) 33702bcd157SAmir Goldstein { 33808f4c7c8SMiklos Szeredi return (!ovl_upper_mnt(ofs) || !ofs->workdir); 33902bcd157SAmir Goldstein } 34002bcd157SAmir Goldstein 341438c84c2SMiklos Szeredi static const char *ovl_redirect_mode_def(void) 342438c84c2SMiklos Szeredi { 343438c84c2SMiklos Szeredi return ovl_redirect_dir_def ? "on" : "off"; 344438c84c2SMiklos Szeredi } 345438c84c2SMiklos Szeredi 346795939a9SAmir Goldstein static const char * const ovl_xino_str[] = { 347795939a9SAmir Goldstein "off", 348795939a9SAmir Goldstein "auto", 349795939a9SAmir Goldstein "on", 350795939a9SAmir Goldstein }; 351795939a9SAmir Goldstein 352795939a9SAmir Goldstein static inline int ovl_xino_def(void) 353795939a9SAmir Goldstein { 354795939a9SAmir Goldstein return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; 355795939a9SAmir Goldstein } 356795939a9SAmir Goldstein 357f45827e8SErez Zadok /** 358f45827e8SErez Zadok * ovl_show_options 3599c5dd803SYang Li * @m: the seq_file handle 3609c5dd803SYang Li * @dentry: The dentry to query 361f45827e8SErez Zadok * 362f45827e8SErez Zadok * Prints the mount options for a given superblock. 363f45827e8SErez Zadok * Returns zero; does not fail. 364f45827e8SErez Zadok */ 365f45827e8SErez Zadok static int ovl_show_options(struct seq_file *m, struct dentry *dentry) 366f45827e8SErez Zadok { 367f45827e8SErez Zadok struct super_block *sb = dentry->d_sb; 368ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 369f45827e8SErez Zadok 370ad204488SMiklos Szeredi seq_show_option(m, "lowerdir", ofs->config.lowerdir); 371ad204488SMiklos Szeredi if (ofs->config.upperdir) { 372ad204488SMiklos Szeredi seq_show_option(m, "upperdir", ofs->config.upperdir); 373ad204488SMiklos Szeredi seq_show_option(m, "workdir", ofs->config.workdir); 37453a08cb9SMiklos Szeredi } 375ad204488SMiklos Szeredi if (ofs->config.default_permissions) 3768d3095f4SMiklos Szeredi seq_puts(m, ",default_permissions"); 377438c84c2SMiklos Szeredi if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) 378438c84c2SMiklos Szeredi seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); 379ad204488SMiklos Szeredi if (ofs->config.index != ovl_index_def) 380438c84c2SMiklos Szeredi seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); 3815830fb6bSPavel Tikhomirov if (!ofs->config.uuid) 3825830fb6bSPavel Tikhomirov seq_puts(m, ",uuid=off"); 383f168f109SAmir Goldstein if (ofs->config.nfs_export != ovl_nfs_export_def) 384f168f109SAmir Goldstein seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? 385f168f109SAmir Goldstein "on" : "off"); 3860f831ec8SAmir Goldstein if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) 387795939a9SAmir Goldstein seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); 388d5791044SVivek Goyal if (ofs->config.metacopy != ovl_metacopy_def) 389d5791044SVivek Goyal seq_printf(m, ",metacopy=%s", 390d5791044SVivek Goyal ofs->config.metacopy ? "on" : "off"); 391c86243b0SVivek Goyal if (ofs->config.ovl_volatile) 392c86243b0SVivek Goyal seq_puts(m, ",volatile"); 393321b46b9SGiuseppe Scrivano if (ofs->config.userxattr) 394321b46b9SGiuseppe Scrivano seq_puts(m, ",userxattr"); 395f45827e8SErez Zadok return 0; 396f45827e8SErez Zadok } 397f45827e8SErez Zadok 3983cdf6fe9SSeunghun Lee static int ovl_remount(struct super_block *sb, int *flags, char *data) 3993cdf6fe9SSeunghun Lee { 400ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 401399c109dSChengguang Xu struct super_block *upper_sb; 402399c109dSChengguang Xu int ret = 0; 4033cdf6fe9SSeunghun Lee 4041751e8a6SLinus Torvalds if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) 4053cdf6fe9SSeunghun Lee return -EROFS; 4063cdf6fe9SSeunghun Lee 407399c109dSChengguang Xu if (*flags & SB_RDONLY && !sb_rdonly(sb)) { 40808f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 409c86243b0SVivek Goyal if (ovl_should_sync(ofs)) { 410399c109dSChengguang Xu down_read(&upper_sb->s_umount); 411399c109dSChengguang Xu ret = sync_filesystem(upper_sb); 412399c109dSChengguang Xu up_read(&upper_sb->s_umount); 413399c109dSChengguang Xu } 414c86243b0SVivek Goyal } 415399c109dSChengguang Xu 416399c109dSChengguang Xu return ret; 4173cdf6fe9SSeunghun Lee } 4183cdf6fe9SSeunghun Lee 419e9be9d5eSMiklos Szeredi static const struct super_operations ovl_super_operations = { 42013cf199dSAmir Goldstein .alloc_inode = ovl_alloc_inode, 4210b269dedSAl Viro .free_inode = ovl_free_inode, 42213cf199dSAmir Goldstein .destroy_inode = ovl_destroy_inode, 42313cf199dSAmir Goldstein .drop_inode = generic_delete_inode, 424e9be9d5eSMiklos Szeredi .put_super = ovl_put_super, 425e593b2bfSAmir Goldstein .sync_fs = ovl_sync_fs, 426cc259639SAndy Whitcroft .statfs = ovl_statfs, 427f45827e8SErez Zadok .show_options = ovl_show_options, 4283cdf6fe9SSeunghun Lee .remount_fs = ovl_remount, 429e9be9d5eSMiklos Szeredi }; 430e9be9d5eSMiklos Szeredi 431e9be9d5eSMiklos Szeredi enum { 432e9be9d5eSMiklos Szeredi OPT_LOWERDIR, 433e9be9d5eSMiklos Szeredi OPT_UPPERDIR, 434e9be9d5eSMiklos Szeredi OPT_WORKDIR, 4358d3095f4SMiklos Szeredi OPT_DEFAULT_PERMISSIONS, 436438c84c2SMiklos Szeredi OPT_REDIRECT_DIR, 43702bcd157SAmir Goldstein OPT_INDEX_ON, 43802bcd157SAmir Goldstein OPT_INDEX_OFF, 4395830fb6bSPavel Tikhomirov OPT_UUID_ON, 4405830fb6bSPavel Tikhomirov OPT_UUID_OFF, 441f168f109SAmir Goldstein OPT_NFS_EXPORT_ON, 4422d2f2d73SMiklos Szeredi OPT_USERXATTR, 443f168f109SAmir Goldstein OPT_NFS_EXPORT_OFF, 444795939a9SAmir Goldstein OPT_XINO_ON, 445795939a9SAmir Goldstein OPT_XINO_OFF, 446795939a9SAmir Goldstein OPT_XINO_AUTO, 447d5791044SVivek Goyal OPT_METACOPY_ON, 448d5791044SVivek Goyal OPT_METACOPY_OFF, 449c86243b0SVivek Goyal OPT_VOLATILE, 450e9be9d5eSMiklos Szeredi OPT_ERR, 451e9be9d5eSMiklos Szeredi }; 452e9be9d5eSMiklos Szeredi 453e9be9d5eSMiklos Szeredi static const match_table_t ovl_tokens = { 454e9be9d5eSMiklos Szeredi {OPT_LOWERDIR, "lowerdir=%s"}, 455e9be9d5eSMiklos Szeredi {OPT_UPPERDIR, "upperdir=%s"}, 456e9be9d5eSMiklos Szeredi {OPT_WORKDIR, "workdir=%s"}, 4578d3095f4SMiklos Szeredi {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 458438c84c2SMiklos Szeredi {OPT_REDIRECT_DIR, "redirect_dir=%s"}, 45902bcd157SAmir Goldstein {OPT_INDEX_ON, "index=on"}, 46002bcd157SAmir Goldstein {OPT_INDEX_OFF, "index=off"}, 4612d2f2d73SMiklos Szeredi {OPT_USERXATTR, "userxattr"}, 4625830fb6bSPavel Tikhomirov {OPT_UUID_ON, "uuid=on"}, 4635830fb6bSPavel Tikhomirov {OPT_UUID_OFF, "uuid=off"}, 464f168f109SAmir Goldstein {OPT_NFS_EXPORT_ON, "nfs_export=on"}, 465f168f109SAmir Goldstein {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, 466795939a9SAmir Goldstein {OPT_XINO_ON, "xino=on"}, 467795939a9SAmir Goldstein {OPT_XINO_OFF, "xino=off"}, 468795939a9SAmir Goldstein {OPT_XINO_AUTO, "xino=auto"}, 469d5791044SVivek Goyal {OPT_METACOPY_ON, "metacopy=on"}, 470d5791044SVivek Goyal {OPT_METACOPY_OFF, "metacopy=off"}, 471c86243b0SVivek Goyal {OPT_VOLATILE, "volatile"}, 472e9be9d5eSMiklos Szeredi {OPT_ERR, NULL} 473e9be9d5eSMiklos Szeredi }; 474e9be9d5eSMiklos Szeredi 47591c77947SMiklos Szeredi static char *ovl_next_opt(char **s) 47691c77947SMiklos Szeredi { 47791c77947SMiklos Szeredi char *sbegin = *s; 47891c77947SMiklos Szeredi char *p; 47991c77947SMiklos Szeredi 48091c77947SMiklos Szeredi if (sbegin == NULL) 48191c77947SMiklos Szeredi return NULL; 48291c77947SMiklos Szeredi 48391c77947SMiklos Szeredi for (p = sbegin; *p; p++) { 48491c77947SMiklos Szeredi if (*p == '\\') { 48591c77947SMiklos Szeredi p++; 48691c77947SMiklos Szeredi if (!*p) 48791c77947SMiklos Szeredi break; 48891c77947SMiklos Szeredi } else if (*p == ',') { 48991c77947SMiklos Szeredi *p = '\0'; 49091c77947SMiklos Szeredi *s = p + 1; 49191c77947SMiklos Szeredi return sbegin; 49291c77947SMiklos Szeredi } 49391c77947SMiklos Szeredi } 49491c77947SMiklos Szeredi *s = NULL; 49591c77947SMiklos Szeredi return sbegin; 49691c77947SMiklos Szeredi } 49791c77947SMiklos Szeredi 498438c84c2SMiklos Szeredi static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) 499438c84c2SMiklos Szeredi { 500438c84c2SMiklos Szeredi if (strcmp(mode, "on") == 0) { 501438c84c2SMiklos Szeredi config->redirect_dir = true; 502438c84c2SMiklos Szeredi /* 503438c84c2SMiklos Szeredi * Does not make sense to have redirect creation without 504438c84c2SMiklos Szeredi * redirect following. 505438c84c2SMiklos Szeredi */ 506438c84c2SMiklos Szeredi config->redirect_follow = true; 507438c84c2SMiklos Szeredi } else if (strcmp(mode, "follow") == 0) { 508438c84c2SMiklos Szeredi config->redirect_follow = true; 509438c84c2SMiklos Szeredi } else if (strcmp(mode, "off") == 0) { 510438c84c2SMiklos Szeredi if (ovl_redirect_always_follow) 511438c84c2SMiklos Szeredi config->redirect_follow = true; 512438c84c2SMiklos Szeredi } else if (strcmp(mode, "nofollow") != 0) { 5131bd0a3aeSlijiazi pr_err("bad mount option \"redirect_dir=%s\"\n", 514438c84c2SMiklos Szeredi mode); 515438c84c2SMiklos Szeredi return -EINVAL; 516438c84c2SMiklos Szeredi } 517438c84c2SMiklos Szeredi 518438c84c2SMiklos Szeredi return 0; 519438c84c2SMiklos Szeredi } 520438c84c2SMiklos Szeredi 521e9be9d5eSMiklos Szeredi static int ovl_parse_opt(char *opt, struct ovl_config *config) 522e9be9d5eSMiklos Szeredi { 523e9be9d5eSMiklos Szeredi char *p; 524d5791044SVivek Goyal int err; 525d47748e5SMiklos Szeredi bool metacopy_opt = false, redirect_opt = false; 526b0def88dSAmir Goldstein bool nfs_export_opt = false, index_opt = false; 527e9be9d5eSMiklos Szeredi 528438c84c2SMiklos Szeredi config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); 529438c84c2SMiklos Szeredi if (!config->redirect_mode) 530438c84c2SMiklos Szeredi return -ENOMEM; 531438c84c2SMiklos Szeredi 53291c77947SMiklos Szeredi while ((p = ovl_next_opt(&opt)) != NULL) { 533e9be9d5eSMiklos Szeredi int token; 534e9be9d5eSMiklos Szeredi substring_t args[MAX_OPT_ARGS]; 535e9be9d5eSMiklos Szeredi 536e9be9d5eSMiklos Szeredi if (!*p) 537e9be9d5eSMiklos Szeredi continue; 538e9be9d5eSMiklos Szeredi 539e9be9d5eSMiklos Szeredi token = match_token(p, ovl_tokens, args); 540e9be9d5eSMiklos Szeredi switch (token) { 541e9be9d5eSMiklos Szeredi case OPT_UPPERDIR: 542e9be9d5eSMiklos Szeredi kfree(config->upperdir); 543e9be9d5eSMiklos Szeredi config->upperdir = match_strdup(&args[0]); 544e9be9d5eSMiklos Szeredi if (!config->upperdir) 545e9be9d5eSMiklos Szeredi return -ENOMEM; 546e9be9d5eSMiklos Szeredi break; 547e9be9d5eSMiklos Szeredi 548e9be9d5eSMiklos Szeredi case OPT_LOWERDIR: 549e9be9d5eSMiklos Szeredi kfree(config->lowerdir); 550e9be9d5eSMiklos Szeredi config->lowerdir = match_strdup(&args[0]); 551e9be9d5eSMiklos Szeredi if (!config->lowerdir) 552e9be9d5eSMiklos Szeredi return -ENOMEM; 553e9be9d5eSMiklos Szeredi break; 554e9be9d5eSMiklos Szeredi 555e9be9d5eSMiklos Szeredi case OPT_WORKDIR: 556e9be9d5eSMiklos Szeredi kfree(config->workdir); 557e9be9d5eSMiklos Szeredi config->workdir = match_strdup(&args[0]); 558e9be9d5eSMiklos Szeredi if (!config->workdir) 559e9be9d5eSMiklos Szeredi return -ENOMEM; 560e9be9d5eSMiklos Szeredi break; 561e9be9d5eSMiklos Szeredi 5628d3095f4SMiklos Szeredi case OPT_DEFAULT_PERMISSIONS: 5638d3095f4SMiklos Szeredi config->default_permissions = true; 5648d3095f4SMiklos Szeredi break; 5658d3095f4SMiklos Szeredi 566438c84c2SMiklos Szeredi case OPT_REDIRECT_DIR: 567438c84c2SMiklos Szeredi kfree(config->redirect_mode); 568438c84c2SMiklos Szeredi config->redirect_mode = match_strdup(&args[0]); 569438c84c2SMiklos Szeredi if (!config->redirect_mode) 570438c84c2SMiklos Szeredi return -ENOMEM; 571d47748e5SMiklos Szeredi redirect_opt = true; 572a6c60655SMiklos Szeredi break; 573a6c60655SMiklos Szeredi 57402bcd157SAmir Goldstein case OPT_INDEX_ON: 57502bcd157SAmir Goldstein config->index = true; 576b0def88dSAmir Goldstein index_opt = true; 57702bcd157SAmir Goldstein break; 57802bcd157SAmir Goldstein 57902bcd157SAmir Goldstein case OPT_INDEX_OFF: 58002bcd157SAmir Goldstein config->index = false; 581b0def88dSAmir Goldstein index_opt = true; 58202bcd157SAmir Goldstein break; 58302bcd157SAmir Goldstein 5845830fb6bSPavel Tikhomirov case OPT_UUID_ON: 5855830fb6bSPavel Tikhomirov config->uuid = true; 5865830fb6bSPavel Tikhomirov break; 5875830fb6bSPavel Tikhomirov 5885830fb6bSPavel Tikhomirov case OPT_UUID_OFF: 5895830fb6bSPavel Tikhomirov config->uuid = false; 5905830fb6bSPavel Tikhomirov break; 5915830fb6bSPavel Tikhomirov 592f168f109SAmir Goldstein case OPT_NFS_EXPORT_ON: 593f168f109SAmir Goldstein config->nfs_export = true; 594b0def88dSAmir Goldstein nfs_export_opt = true; 595f168f109SAmir Goldstein break; 596f168f109SAmir Goldstein 597f168f109SAmir Goldstein case OPT_NFS_EXPORT_OFF: 598f168f109SAmir Goldstein config->nfs_export = false; 599b0def88dSAmir Goldstein nfs_export_opt = true; 600f168f109SAmir Goldstein break; 601f168f109SAmir Goldstein 602795939a9SAmir Goldstein case OPT_XINO_ON: 603795939a9SAmir Goldstein config->xino = OVL_XINO_ON; 604795939a9SAmir Goldstein break; 605795939a9SAmir Goldstein 606795939a9SAmir Goldstein case OPT_XINO_OFF: 607795939a9SAmir Goldstein config->xino = OVL_XINO_OFF; 608795939a9SAmir Goldstein break; 609795939a9SAmir Goldstein 610795939a9SAmir Goldstein case OPT_XINO_AUTO: 611795939a9SAmir Goldstein config->xino = OVL_XINO_AUTO; 612795939a9SAmir Goldstein break; 613795939a9SAmir Goldstein 614d5791044SVivek Goyal case OPT_METACOPY_ON: 615d5791044SVivek Goyal config->metacopy = true; 616d47748e5SMiklos Szeredi metacopy_opt = true; 617d5791044SVivek Goyal break; 618d5791044SVivek Goyal 619d5791044SVivek Goyal case OPT_METACOPY_OFF: 620d5791044SVivek Goyal config->metacopy = false; 621b0def88dSAmir Goldstein metacopy_opt = true; 622d5791044SVivek Goyal break; 623d5791044SVivek Goyal 624c86243b0SVivek Goyal case OPT_VOLATILE: 625c86243b0SVivek Goyal config->ovl_volatile = true; 626c86243b0SVivek Goyal break; 627c86243b0SVivek Goyal 6282d2f2d73SMiklos Szeredi case OPT_USERXATTR: 6292d2f2d73SMiklos Szeredi config->userxattr = true; 6302d2f2d73SMiklos Szeredi break; 6312d2f2d73SMiklos Szeredi 632e9be9d5eSMiklos Szeredi default: 6331bd0a3aeSlijiazi pr_err("unrecognized mount option \"%s\" or missing value\n", 6341bd0a3aeSlijiazi p); 635e9be9d5eSMiklos Szeredi return -EINVAL; 636e9be9d5eSMiklos Szeredi } 637e9be9d5eSMiklos Szeredi } 63871cbad7eShujianyang 639f0e1266eSAmir Goldstein /* Workdir/index are useless in non-upper mount */ 640f0e1266eSAmir Goldstein if (!config->upperdir) { 641f0e1266eSAmir Goldstein if (config->workdir) { 6421bd0a3aeSlijiazi pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", 64371cbad7eShujianyang config->workdir); 64471cbad7eShujianyang kfree(config->workdir); 64571cbad7eShujianyang config->workdir = NULL; 64671cbad7eShujianyang } 647f0e1266eSAmir Goldstein if (config->index && index_opt) { 648f0e1266eSAmir Goldstein pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); 649f0e1266eSAmir Goldstein index_opt = false; 650f0e1266eSAmir Goldstein } 651f0e1266eSAmir Goldstein config->index = false; 652f0e1266eSAmir Goldstein } 65371cbad7eShujianyang 654c86243b0SVivek Goyal if (!config->upperdir && config->ovl_volatile) { 655c86243b0SVivek Goyal pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); 656c86243b0SVivek Goyal config->ovl_volatile = false; 657c86243b0SVivek Goyal } 658c86243b0SVivek Goyal 659d5791044SVivek Goyal err = ovl_parse_redirect_mode(config, config->redirect_mode); 660d5791044SVivek Goyal if (err) 661d5791044SVivek Goyal return err; 662d5791044SVivek Goyal 663d47748e5SMiklos Szeredi /* 664d47748e5SMiklos Szeredi * This is to make the logic below simpler. It doesn't make any other 665d47748e5SMiklos Szeredi * difference, since config->redirect_dir is only used for upper. 666d47748e5SMiklos Szeredi */ 667d47748e5SMiklos Szeredi if (!config->upperdir && config->redirect_follow) 668d47748e5SMiklos Szeredi config->redirect_dir = true; 669d47748e5SMiklos Szeredi 670d47748e5SMiklos Szeredi /* Resolve metacopy -> redirect_dir dependency */ 671d47748e5SMiklos Szeredi if (config->metacopy && !config->redirect_dir) { 672d47748e5SMiklos Szeredi if (metacopy_opt && redirect_opt) { 6731bd0a3aeSlijiazi pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", 674d47748e5SMiklos Szeredi config->redirect_mode); 675d47748e5SMiklos Szeredi return -EINVAL; 676d47748e5SMiklos Szeredi } 677d47748e5SMiklos Szeredi if (redirect_opt) { 678d47748e5SMiklos Szeredi /* 679d47748e5SMiklos Szeredi * There was an explicit redirect_dir=... that resulted 680d47748e5SMiklos Szeredi * in this conflict. 681d47748e5SMiklos Szeredi */ 6821bd0a3aeSlijiazi pr_info("disabling metacopy due to redirect_dir=%s\n", 683d47748e5SMiklos Szeredi config->redirect_mode); 684d5791044SVivek Goyal config->metacopy = false; 685d47748e5SMiklos Szeredi } else { 686d47748e5SMiklos Szeredi /* Automatically enable redirect otherwise. */ 687d47748e5SMiklos Szeredi config->redirect_follow = config->redirect_dir = true; 688d47748e5SMiklos Szeredi } 689d5791044SVivek Goyal } 690d5791044SVivek Goyal 691b0def88dSAmir Goldstein /* Resolve nfs_export -> index dependency */ 692b0def88dSAmir Goldstein if (config->nfs_export && !config->index) { 693f0e1266eSAmir Goldstein if (!config->upperdir && config->redirect_follow) { 694f0e1266eSAmir Goldstein pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); 695f0e1266eSAmir Goldstein config->nfs_export = false; 696f0e1266eSAmir Goldstein } else if (nfs_export_opt && index_opt) { 697b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,index=off\n"); 698b0def88dSAmir Goldstein return -EINVAL; 699f0e1266eSAmir Goldstein } else if (index_opt) { 700b0def88dSAmir Goldstein /* 701b0def88dSAmir Goldstein * There was an explicit index=off that resulted 702b0def88dSAmir Goldstein * in this conflict. 703b0def88dSAmir Goldstein */ 704b0def88dSAmir Goldstein pr_info("disabling nfs_export due to index=off\n"); 705b0def88dSAmir Goldstein config->nfs_export = false; 706b0def88dSAmir Goldstein } else { 707b0def88dSAmir Goldstein /* Automatically enable index otherwise. */ 708b0def88dSAmir Goldstein config->index = true; 709b0def88dSAmir Goldstein } 710b0def88dSAmir Goldstein } 711b0def88dSAmir Goldstein 712b0def88dSAmir Goldstein /* Resolve nfs_export -> !metacopy dependency */ 713b0def88dSAmir Goldstein if (config->nfs_export && config->metacopy) { 714b0def88dSAmir Goldstein if (nfs_export_opt && metacopy_opt) { 715b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,metacopy=on\n"); 716b0def88dSAmir Goldstein return -EINVAL; 717b0def88dSAmir Goldstein } 718b0def88dSAmir Goldstein if (metacopy_opt) { 719b0def88dSAmir Goldstein /* 720b0def88dSAmir Goldstein * There was an explicit metacopy=on that resulted 721b0def88dSAmir Goldstein * in this conflict. 722b0def88dSAmir Goldstein */ 723b0def88dSAmir Goldstein pr_info("disabling nfs_export due to metacopy=on\n"); 724b0def88dSAmir Goldstein config->nfs_export = false; 725b0def88dSAmir Goldstein } else { 726b0def88dSAmir Goldstein /* 727b0def88dSAmir Goldstein * There was an explicit nfs_export=on that resulted 728b0def88dSAmir Goldstein * in this conflict. 729b0def88dSAmir Goldstein */ 730b0def88dSAmir Goldstein pr_info("disabling metacopy due to nfs_export=on\n"); 731b0def88dSAmir Goldstein config->metacopy = false; 732b0def88dSAmir Goldstein } 733b0def88dSAmir Goldstein } 734b0def88dSAmir Goldstein 7352d2f2d73SMiklos Szeredi 7362d2f2d73SMiklos Szeredi /* Resolve userxattr -> !redirect && !metacopy dependency */ 7372d2f2d73SMiklos Szeredi if (config->userxattr) { 7382d2f2d73SMiklos Szeredi if (config->redirect_follow && redirect_opt) { 7392d2f2d73SMiklos Szeredi pr_err("conflicting options: userxattr,redirect_dir=%s\n", 7402d2f2d73SMiklos Szeredi config->redirect_mode); 7412d2f2d73SMiklos Szeredi return -EINVAL; 7422d2f2d73SMiklos Szeredi } 7432d2f2d73SMiklos Szeredi if (config->metacopy && metacopy_opt) { 7442d2f2d73SMiklos Szeredi pr_err("conflicting options: userxattr,metacopy=on\n"); 7452d2f2d73SMiklos Szeredi return -EINVAL; 7462d2f2d73SMiklos Szeredi } 7472d2f2d73SMiklos Szeredi /* 7482d2f2d73SMiklos Szeredi * Silently disable default setting of redirect and metacopy. 7492d2f2d73SMiklos Szeredi * This shall be the default in the future as well: these 7502d2f2d73SMiklos Szeredi * options must be explicitly enabled if used together with 7512d2f2d73SMiklos Szeredi * userxattr. 7522d2f2d73SMiklos Szeredi */ 7532d2f2d73SMiklos Szeredi config->redirect_dir = config->redirect_follow = false; 7542d2f2d73SMiklos Szeredi config->metacopy = false; 7552d2f2d73SMiklos Szeredi } 7562d2f2d73SMiklos Szeredi 757d5791044SVivek Goyal return 0; 758e9be9d5eSMiklos Szeredi } 759e9be9d5eSMiklos Szeredi 760e9be9d5eSMiklos Szeredi #define OVL_WORKDIR_NAME "work" 76102bcd157SAmir Goldstein #define OVL_INDEXDIR_NAME "index" 762e9be9d5eSMiklos Szeredi 763ad204488SMiklos Szeredi static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, 7646b8aa129SAmir Goldstein const char *name, bool persist) 765e9be9d5eSMiklos Szeredi { 766ad204488SMiklos Szeredi struct inode *dir = ofs->workbasedir->d_inode; 76708f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 768e9be9d5eSMiklos Szeredi struct dentry *work; 769e9be9d5eSMiklos Szeredi int err; 770e9be9d5eSMiklos Szeredi bool retried = false; 771e9be9d5eSMiklos Szeredi 7725955102cSAl Viro inode_lock_nested(dir, I_MUTEX_PARENT); 773e9be9d5eSMiklos Szeredi retry: 77422f289ceSChristian Brauner work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); 775e9be9d5eSMiklos Szeredi 776e9be9d5eSMiklos Szeredi if (!IS_ERR(work)) { 777c11b9fddSMiklos Szeredi struct iattr attr = { 778c11b9fddSMiklos Szeredi .ia_valid = ATTR_MODE, 77932a3d848SAl Viro .ia_mode = S_IFDIR | 0, 780c11b9fddSMiklos Szeredi }; 781e9be9d5eSMiklos Szeredi 782e9be9d5eSMiklos Szeredi if (work->d_inode) { 783e9be9d5eSMiklos Szeredi err = -EEXIST; 784e9be9d5eSMiklos Szeredi if (retried) 785e9be9d5eSMiklos Szeredi goto out_dput; 786e9be9d5eSMiklos Szeredi 7876b8aa129SAmir Goldstein if (persist) 7886b8aa129SAmir Goldstein goto out_unlock; 7896b8aa129SAmir Goldstein 790e9be9d5eSMiklos Szeredi retried = true; 791576bb263SChristian Brauner err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); 792e9be9d5eSMiklos Szeredi dput(work); 793235ce9edSAmir Goldstein if (err == -EINVAL) { 794235ce9edSAmir Goldstein work = ERR_PTR(err); 795235ce9edSAmir Goldstein goto out_unlock; 796235ce9edSAmir Goldstein } 797e9be9d5eSMiklos Szeredi goto retry; 798e9be9d5eSMiklos Szeredi } 799e9be9d5eSMiklos Szeredi 800576bb263SChristian Brauner err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); 8011f5573cfSMiklos Szeredi if (err) 8021f5573cfSMiklos Szeredi goto out_dput; 8031f5573cfSMiklos Szeredi 8041f5573cfSMiklos Szeredi /* Weird filesystem returning with hashed negative (kernfs)? */ 8051f5573cfSMiklos Szeredi err = -EINVAL; 8061f5573cfSMiklos Szeredi if (d_really_is_negative(work)) 8071f5573cfSMiklos Szeredi goto out_dput; 808c11b9fddSMiklos Szeredi 809cb348edbSMiklos Szeredi /* 810cb348edbSMiklos Szeredi * Try to remove POSIX ACL xattrs from workdir. We are good if: 811cb348edbSMiklos Szeredi * 812cb348edbSMiklos Szeredi * a) success (there was a POSIX ACL xattr and was removed) 813cb348edbSMiklos Szeredi * b) -ENODATA (there was no POSIX ACL xattr) 814cb348edbSMiklos Szeredi * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) 815cb348edbSMiklos Szeredi * 816cb348edbSMiklos Szeredi * There are various other error values that could effectively 817cb348edbSMiklos Szeredi * mean that the xattr doesn't exist (e.g. -ERANGE is returned 818cb348edbSMiklos Szeredi * if the xattr name is too long), but the set of filesystems 819cb348edbSMiklos Szeredi * allowed as upper are limited to "normal" ones, where checking 820cb348edbSMiklos Szeredi * for the above two errors is sufficient. 821cb348edbSMiklos Szeredi */ 82231acceb9SChristian Brauner err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT); 823e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 824c11b9fddSMiklos Szeredi goto out_dput; 825c11b9fddSMiklos Szeredi 82631acceb9SChristian Brauner err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS); 827e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 828c11b9fddSMiklos Szeredi goto out_dput; 829c11b9fddSMiklos Szeredi 830c11b9fddSMiklos Szeredi /* Clear any inherited mode bits */ 831c11b9fddSMiklos Szeredi inode_lock(work->d_inode); 832a15506eaSChristian Brauner err = ovl_do_notify_change(ofs, work, &attr); 833c11b9fddSMiklos Szeredi inode_unlock(work->d_inode); 834c11b9fddSMiklos Szeredi if (err) 835c11b9fddSMiklos Szeredi goto out_dput; 8366b8aa129SAmir Goldstein } else { 8376b8aa129SAmir Goldstein err = PTR_ERR(work); 8386b8aa129SAmir Goldstein goto out_err; 839e9be9d5eSMiklos Szeredi } 840e9be9d5eSMiklos Szeredi out_unlock: 8416b8aa129SAmir Goldstein inode_unlock(dir); 842e9be9d5eSMiklos Szeredi return work; 843e9be9d5eSMiklos Szeredi 844e9be9d5eSMiklos Szeredi out_dput: 845e9be9d5eSMiklos Szeredi dput(work); 8466b8aa129SAmir Goldstein out_err: 8471bd0a3aeSlijiazi pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", 848ad204488SMiklos Szeredi ofs->config.workdir, name, -err); 8496b8aa129SAmir Goldstein work = NULL; 850e9be9d5eSMiklos Szeredi goto out_unlock; 851e9be9d5eSMiklos Szeredi } 852e9be9d5eSMiklos Szeredi 85391c77947SMiklos Szeredi static void ovl_unescape(char *s) 85491c77947SMiklos Szeredi { 85591c77947SMiklos Szeredi char *d = s; 85691c77947SMiklos Szeredi 85791c77947SMiklos Szeredi for (;; s++, d++) { 85891c77947SMiklos Szeredi if (*s == '\\') 85991c77947SMiklos Szeredi s++; 86091c77947SMiklos Szeredi *d = *s; 86191c77947SMiklos Szeredi if (!*s) 86291c77947SMiklos Szeredi break; 86391c77947SMiklos Szeredi } 86491c77947SMiklos Szeredi } 86591c77947SMiklos Szeredi 866ab508822SMiklos Szeredi static int ovl_mount_dir_noesc(const char *name, struct path *path) 867ab508822SMiklos Szeredi { 868a78d9f0dSMiklos Szeredi int err = -EINVAL; 869ab508822SMiklos Szeredi 870a78d9f0dSMiklos Szeredi if (!*name) { 8711bd0a3aeSlijiazi pr_err("empty lowerdir\n"); 872a78d9f0dSMiklos Szeredi goto out; 873a78d9f0dSMiklos Szeredi } 874ab508822SMiklos Szeredi err = kern_path(name, LOOKUP_FOLLOW, path); 875ab508822SMiklos Szeredi if (err) { 8761bd0a3aeSlijiazi pr_err("failed to resolve '%s': %i\n", name, err); 877ab508822SMiklos Szeredi goto out; 878ab508822SMiklos Szeredi } 879ab508822SMiklos Szeredi err = -EINVAL; 8807c03b5d4SMiklos Szeredi if (ovl_dentry_weird(path->dentry)) { 8811bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported\n", name); 882ab508822SMiklos Szeredi goto out_put; 883ab508822SMiklos Szeredi } 8842b8c30e9SMiklos Szeredi if (!d_is_dir(path->dentry)) { 8851bd0a3aeSlijiazi pr_err("'%s' not a directory\n", name); 886ab508822SMiklos Szeredi goto out_put; 887ab508822SMiklos Szeredi } 888ab508822SMiklos Szeredi return 0; 889ab508822SMiklos Szeredi 890ab508822SMiklos Szeredi out_put: 8918aafcb59SMiklos Szeredi path_put_init(path); 892ab508822SMiklos Szeredi out: 893ab508822SMiklos Szeredi return err; 894ab508822SMiklos Szeredi } 895ab508822SMiklos Szeredi 896ab508822SMiklos Szeredi static int ovl_mount_dir(const char *name, struct path *path) 897ab508822SMiklos Szeredi { 898ab508822SMiklos Szeredi int err = -ENOMEM; 899ab508822SMiklos Szeredi char *tmp = kstrdup(name, GFP_KERNEL); 900ab508822SMiklos Szeredi 901ab508822SMiklos Szeredi if (tmp) { 902ab508822SMiklos Szeredi ovl_unescape(tmp); 903ab508822SMiklos Szeredi err = ovl_mount_dir_noesc(tmp, path); 9047c03b5d4SMiklos Szeredi 905bccece1eSMiklos Szeredi if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { 9061bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported as upperdir\n", 9077c03b5d4SMiklos Szeredi tmp); 9088aafcb59SMiklos Szeredi path_put_init(path); 9097c03b5d4SMiklos Szeredi err = -EINVAL; 9107c03b5d4SMiklos Szeredi } 911ab508822SMiklos Szeredi kfree(tmp); 912ab508822SMiklos Szeredi } 913ab508822SMiklos Szeredi return err; 914ab508822SMiklos Szeredi } 915ab508822SMiklos Szeredi 9162d343087SAl Viro static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, 9176b2d5fe4SMiklos Szeredi const char *name) 9186b2d5fe4SMiklos Szeredi { 9196b2d5fe4SMiklos Szeredi struct kstatfs statfs; 9206b2d5fe4SMiklos Szeredi int err = vfs_statfs(path, &statfs); 9216b2d5fe4SMiklos Szeredi 9226b2d5fe4SMiklos Szeredi if (err) 9231bd0a3aeSlijiazi pr_err("statfs failed on '%s'\n", name); 9246b2d5fe4SMiklos Szeredi else 9256b2d5fe4SMiklos Szeredi ofs->namelen = max(ofs->namelen, statfs.f_namelen); 9266b2d5fe4SMiklos Szeredi 9276b2d5fe4SMiklos Szeredi return err; 9286b2d5fe4SMiklos Szeredi } 9296b2d5fe4SMiklos Szeredi 9306b2d5fe4SMiklos Szeredi static int ovl_lower_dir(const char *name, struct path *path, 931f4288844SMiklos Szeredi struct ovl_fs *ofs, int *stack_depth) 932ab508822SMiklos Szeredi { 933e487d889SAmir Goldstein int fh_type; 934ab508822SMiklos Szeredi int err; 935ab508822SMiklos Szeredi 936a78d9f0dSMiklos Szeredi err = ovl_mount_dir_noesc(name, path); 937ab508822SMiklos Szeredi if (err) 938b8e42a65SMiklos Szeredi return err; 939ab508822SMiklos Szeredi 9406b2d5fe4SMiklos Szeredi err = ovl_check_namelen(path, ofs, name); 9416b2d5fe4SMiklos Szeredi if (err) 942b8e42a65SMiklos Szeredi return err; 9436b2d5fe4SMiklos Szeredi 944ab508822SMiklos Szeredi *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); 945ab508822SMiklos Szeredi 94602bcd157SAmir Goldstein /* 947f168f109SAmir Goldstein * The inodes index feature and NFS export need to encode and decode 948f168f109SAmir Goldstein * file handles, so they require that all layers support them. 94902bcd157SAmir Goldstein */ 950e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(path->dentry->d_sb); 951f168f109SAmir Goldstein if ((ofs->config.nfs_export || 952e487d889SAmir Goldstein (ofs->config.index && ofs->config.upperdir)) && !fh_type) { 95302bcd157SAmir Goldstein ofs->config.index = false; 954f168f109SAmir Goldstein ofs->config.nfs_export = false; 9551bd0a3aeSlijiazi pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", 956f168f109SAmir Goldstein name); 95702bcd157SAmir Goldstein } 958b0e0f697SAmir Goldstein /* 959b0e0f697SAmir Goldstein * Decoding origin file handle is required for persistent st_ino. 960b0e0f697SAmir Goldstein * Without persistent st_ino, xino=auto falls back to xino=off. 961b0e0f697SAmir Goldstein */ 962b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO && 963b0e0f697SAmir Goldstein ofs->config.upperdir && !fh_type) { 964b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 965b0e0f697SAmir Goldstein pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", 966b0e0f697SAmir Goldstein name); 967b0e0f697SAmir Goldstein } 96802bcd157SAmir Goldstein 969e487d889SAmir Goldstein /* Check if lower fs has 32bit inode numbers */ 970e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 9710f831ec8SAmir Goldstein ofs->xino_mode = -1; 972e487d889SAmir Goldstein 973ab508822SMiklos Szeredi return 0; 974ab508822SMiklos Szeredi } 975ab508822SMiklos Szeredi 976e9be9d5eSMiklos Szeredi /* Workdir should not be subdir of upperdir and vice versa */ 977e9be9d5eSMiklos Szeredi static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) 978e9be9d5eSMiklos Szeredi { 979e9be9d5eSMiklos Szeredi bool ok = false; 980e9be9d5eSMiklos Szeredi 981e9be9d5eSMiklos Szeredi if (workdir != upperdir) { 982e9be9d5eSMiklos Szeredi ok = (lock_rename(workdir, upperdir) == NULL); 983e9be9d5eSMiklos Szeredi unlock_rename(workdir, upperdir); 984e9be9d5eSMiklos Szeredi } 985e9be9d5eSMiklos Szeredi return ok; 986e9be9d5eSMiklos Szeredi } 987e9be9d5eSMiklos Szeredi 988a78d9f0dSMiklos Szeredi static unsigned int ovl_split_lowerdirs(char *str) 989a78d9f0dSMiklos Szeredi { 990a78d9f0dSMiklos Szeredi unsigned int ctr = 1; 991a78d9f0dSMiklos Szeredi char *s, *d; 992a78d9f0dSMiklos Szeredi 993a78d9f0dSMiklos Szeredi for (s = d = str;; s++, d++) { 994a78d9f0dSMiklos Szeredi if (*s == '\\') { 995a78d9f0dSMiklos Szeredi s++; 996a78d9f0dSMiklos Szeredi } else if (*s == ':') { 997a78d9f0dSMiklos Szeredi *d = '\0'; 998a78d9f0dSMiklos Szeredi ctr++; 999a78d9f0dSMiklos Szeredi continue; 1000a78d9f0dSMiklos Szeredi } 1001a78d9f0dSMiklos Szeredi *d = *s; 1002a78d9f0dSMiklos Szeredi if (!*s) 1003a78d9f0dSMiklos Szeredi break; 1004a78d9f0dSMiklos Szeredi } 1005a78d9f0dSMiklos Szeredi return ctr; 1006a78d9f0dSMiklos Szeredi } 1007a78d9f0dSMiklos Szeredi 10080eb45fc3SAndreas Gruenbacher static int ovl_own_xattr_get(const struct xattr_handler *handler, 10090eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10100eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10110eb45fc3SAndreas Gruenbacher { 101248fab5d7SAmir Goldstein return -EOPNOTSUPP; 10130eb45fc3SAndreas Gruenbacher } 10140eb45fc3SAndreas Gruenbacher 1015d837a49bSMiklos Szeredi static int ovl_own_xattr_set(const struct xattr_handler *handler, 101639f60c1cSChristian Brauner struct mnt_idmap *idmap, 1017d837a49bSMiklos Szeredi struct dentry *dentry, struct inode *inode, 1018d837a49bSMiklos Szeredi const char *name, const void *value, 1019d837a49bSMiklos Szeredi size_t size, int flags) 1020d837a49bSMiklos Szeredi { 102148fab5d7SAmir Goldstein return -EOPNOTSUPP; 1022d837a49bSMiklos Szeredi } 1023d837a49bSMiklos Szeredi 10240eb45fc3SAndreas Gruenbacher static int ovl_other_xattr_get(const struct xattr_handler *handler, 10250eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10260eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10270eb45fc3SAndreas Gruenbacher { 10281d88f183SMiklos Szeredi return ovl_xattr_get(dentry, inode, name, buffer, size); 10290eb45fc3SAndreas Gruenbacher } 10300eb45fc3SAndreas Gruenbacher 10310e585cccSAndreas Gruenbacher static int ovl_other_xattr_set(const struct xattr_handler *handler, 103239f60c1cSChristian Brauner struct mnt_idmap *idmap, 10330e585cccSAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10340e585cccSAndreas Gruenbacher const char *name, const void *value, 10350e585cccSAndreas Gruenbacher size_t size, int flags) 10360e585cccSAndreas Gruenbacher { 10371d88f183SMiklos Szeredi return ovl_xattr_set(dentry, inode, name, value, size, flags); 10380e585cccSAndreas Gruenbacher } 10390e585cccSAndreas Gruenbacher 10402d2f2d73SMiklos Szeredi static const struct xattr_handler ovl_own_trusted_xattr_handler = { 10412d2f2d73SMiklos Szeredi .prefix = OVL_XATTR_TRUSTED_PREFIX, 10422d2f2d73SMiklos Szeredi .get = ovl_own_xattr_get, 10432d2f2d73SMiklos Szeredi .set = ovl_own_xattr_set, 10442d2f2d73SMiklos Szeredi }; 10452d2f2d73SMiklos Szeredi 10462d2f2d73SMiklos Szeredi static const struct xattr_handler ovl_own_user_xattr_handler = { 10472d2f2d73SMiklos Szeredi .prefix = OVL_XATTR_USER_PREFIX, 10480eb45fc3SAndreas Gruenbacher .get = ovl_own_xattr_get, 1049d837a49bSMiklos Szeredi .set = ovl_own_xattr_set, 1050d837a49bSMiklos Szeredi }; 1051d837a49bSMiklos Szeredi 1052d837a49bSMiklos Szeredi static const struct xattr_handler ovl_other_xattr_handler = { 1053d837a49bSMiklos Szeredi .prefix = "", /* catch all */ 10540eb45fc3SAndreas Gruenbacher .get = ovl_other_xattr_get, 1055d837a49bSMiklos Szeredi .set = ovl_other_xattr_set, 1056d837a49bSMiklos Szeredi }; 1057d837a49bSMiklos Szeredi 10582d2f2d73SMiklos Szeredi static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { 10592d2f2d73SMiklos Szeredi &ovl_own_trusted_xattr_handler, 10602d2f2d73SMiklos Szeredi &ovl_other_xattr_handler, 10612d2f2d73SMiklos Szeredi NULL 10622d2f2d73SMiklos Szeredi }; 10632d2f2d73SMiklos Szeredi 10642d2f2d73SMiklos Szeredi static const struct xattr_handler *ovl_user_xattr_handlers[] = { 10652d2f2d73SMiklos Szeredi &ovl_own_user_xattr_handler, 1066d837a49bSMiklos Szeredi &ovl_other_xattr_handler, 1067d837a49bSMiklos Szeredi NULL 1068d837a49bSMiklos Szeredi }; 1069d837a49bSMiklos Szeredi 1070146d62e5SAmir Goldstein static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, 1071146d62e5SAmir Goldstein struct inode **ptrap, const char *name) 1072146d62e5SAmir Goldstein { 1073146d62e5SAmir Goldstein struct inode *trap; 1074146d62e5SAmir Goldstein int err; 1075146d62e5SAmir Goldstein 1076146d62e5SAmir Goldstein trap = ovl_get_trap_inode(sb, dir); 10771dac6f5bSArnd Bergmann err = PTR_ERR_OR_ZERO(trap); 10781dac6f5bSArnd Bergmann if (err) { 1079146d62e5SAmir Goldstein if (err == -ELOOP) 10801bd0a3aeSlijiazi pr_err("conflicting %s path\n", name); 1081146d62e5SAmir Goldstein return err; 1082146d62e5SAmir Goldstein } 1083146d62e5SAmir Goldstein 1084146d62e5SAmir Goldstein *ptrap = trap; 1085146d62e5SAmir Goldstein return 0; 1086146d62e5SAmir Goldstein } 1087146d62e5SAmir Goldstein 10880be0bfd2SAmir Goldstein /* 10890be0bfd2SAmir Goldstein * Determine how we treat concurrent use of upperdir/workdir based on the 10900be0bfd2SAmir Goldstein * index feature. This is papering over mount leaks of container runtimes, 10910be0bfd2SAmir Goldstein * for example, an old overlay mount is leaked and now its upperdir is 10920be0bfd2SAmir Goldstein * attempted to be used as a lower layer in a new overlay mount. 10930be0bfd2SAmir Goldstein */ 10940be0bfd2SAmir Goldstein static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) 10950be0bfd2SAmir Goldstein { 10960be0bfd2SAmir Goldstein if (ofs->config.index) { 10971bd0a3aeSlijiazi pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", 10980be0bfd2SAmir Goldstein name); 10990be0bfd2SAmir Goldstein return -EBUSY; 11000be0bfd2SAmir Goldstein } else { 11011bd0a3aeSlijiazi pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", 11020be0bfd2SAmir Goldstein name); 11030be0bfd2SAmir Goldstein return 0; 11040be0bfd2SAmir Goldstein } 11050be0bfd2SAmir Goldstein } 11060be0bfd2SAmir Goldstein 1107146d62e5SAmir Goldstein static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, 1108b8e42a65SMiklos Szeredi struct ovl_layer *upper_layer, struct path *upperpath) 11096ee8acf0SMiklos Szeredi { 11105064975eSMiklos Szeredi struct vfsmount *upper_mnt; 11116ee8acf0SMiklos Szeredi int err; 11126ee8acf0SMiklos Szeredi 1113ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.upperdir, upperpath); 11146ee8acf0SMiklos Szeredi if (err) 11156ee8acf0SMiklos Szeredi goto out; 11166ee8acf0SMiklos Szeredi 1117e21a6c57SAmir Goldstein /* Upperdir path should not be r/o */ 1118e21a6c57SAmir Goldstein if (__mnt_is_readonly(upperpath->mnt)) { 11191bd0a3aeSlijiazi pr_err("upper fs is r/o, try multi-lower layers mount\n"); 11206ee8acf0SMiklos Szeredi err = -EINVAL; 11216ee8acf0SMiklos Szeredi goto out; 11226ee8acf0SMiklos Szeredi } 11236ee8acf0SMiklos Szeredi 1124ad204488SMiklos Szeredi err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); 11256ee8acf0SMiklos Szeredi if (err) 11266ee8acf0SMiklos Szeredi goto out; 11276ee8acf0SMiklos Szeredi 1128b8e42a65SMiklos Szeredi err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, 1129146d62e5SAmir Goldstein "upperdir"); 1130146d62e5SAmir Goldstein if (err) 1131146d62e5SAmir Goldstein goto out; 1132146d62e5SAmir Goldstein 11335064975eSMiklos Szeredi upper_mnt = clone_private_mount(upperpath); 11345064975eSMiklos Szeredi err = PTR_ERR(upper_mnt); 11355064975eSMiklos Szeredi if (IS_ERR(upper_mnt)) { 11361bd0a3aeSlijiazi pr_err("failed to clone upperpath\n"); 11375064975eSMiklos Szeredi goto out; 11385064975eSMiklos Szeredi } 11395064975eSMiklos Szeredi 11405064975eSMiklos Szeredi /* Don't inherit atime flags */ 11415064975eSMiklos Szeredi upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); 1142b8e42a65SMiklos Szeredi upper_layer->mnt = upper_mnt; 1143b8e42a65SMiklos Szeredi upper_layer->idx = 0; 1144b8e42a65SMiklos Szeredi upper_layer->fsid = 0; 11458c25741aSMiklos Szeredi 1146654255faSJeffle Xu /* 1147654255faSJeffle Xu * Inherit SB_NOSEC flag from upperdir. 1148654255faSJeffle Xu * 1149654255faSJeffle Xu * This optimization changes behavior when a security related attribute 1150654255faSJeffle Xu * (suid/sgid/security.*) is changed on an underlying layer. This is 1151654255faSJeffle Xu * okay because we don't yet have guarantees in that case, but it will 1152654255faSJeffle Xu * need careful treatment once we want to honour changes to underlying 1153654255faSJeffle Xu * filesystems. 1154654255faSJeffle Xu */ 1155654255faSJeffle Xu if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) 1156654255faSJeffle Xu sb->s_flags |= SB_NOSEC; 1157654255faSJeffle Xu 115808f4c7c8SMiklos Szeredi if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { 11598c25741aSMiklos Szeredi ofs->upperdir_locked = true; 11608c25741aSMiklos Szeredi } else { 11610be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "upperdir"); 11620be0bfd2SAmir Goldstein if (err) 11630be0bfd2SAmir Goldstein goto out; 11648c25741aSMiklos Szeredi } 11658c25741aSMiklos Szeredi 11666ee8acf0SMiklos Szeredi err = 0; 11676ee8acf0SMiklos Szeredi out: 11686ee8acf0SMiklos Szeredi return err; 11696ee8acf0SMiklos Szeredi } 11706ee8acf0SMiklos Szeredi 1171cad218abSAmir Goldstein /* 1172cad218abSAmir Goldstein * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and 1173cad218abSAmir Goldstein * negative values if error is encountered. 1174cad218abSAmir Goldstein */ 1175576bb263SChristian Brauner static int ovl_check_rename_whiteout(struct ovl_fs *ofs) 1176cad218abSAmir Goldstein { 1177576bb263SChristian Brauner struct dentry *workdir = ofs->workdir; 1178cad218abSAmir Goldstein struct inode *dir = d_inode(workdir); 1179cad218abSAmir Goldstein struct dentry *temp; 1180cad218abSAmir Goldstein struct dentry *dest; 1181cad218abSAmir Goldstein struct dentry *whiteout; 1182cad218abSAmir Goldstein struct name_snapshot name; 1183cad218abSAmir Goldstein int err; 1184cad218abSAmir Goldstein 1185cad218abSAmir Goldstein inode_lock_nested(dir, I_MUTEX_PARENT); 1186cad218abSAmir Goldstein 1187576bb263SChristian Brauner temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); 1188cad218abSAmir Goldstein err = PTR_ERR(temp); 1189cad218abSAmir Goldstein if (IS_ERR(temp)) 1190cad218abSAmir Goldstein goto out_unlock; 1191cad218abSAmir Goldstein 1192576bb263SChristian Brauner dest = ovl_lookup_temp(ofs, workdir); 1193cad218abSAmir Goldstein err = PTR_ERR(dest); 1194cad218abSAmir Goldstein if (IS_ERR(dest)) { 1195cad218abSAmir Goldstein dput(temp); 1196cad218abSAmir Goldstein goto out_unlock; 1197cad218abSAmir Goldstein } 1198cad218abSAmir Goldstein 1199cad218abSAmir Goldstein /* Name is inline and stable - using snapshot as a copy helper */ 1200cad218abSAmir Goldstein take_dentry_name_snapshot(&name, temp); 1201576bb263SChristian Brauner err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); 1202cad218abSAmir Goldstein if (err) { 1203cad218abSAmir Goldstein if (err == -EINVAL) 1204cad218abSAmir Goldstein err = 0; 1205cad218abSAmir Goldstein goto cleanup_temp; 1206cad218abSAmir Goldstein } 1207cad218abSAmir Goldstein 120822f289ceSChristian Brauner whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); 1209cad218abSAmir Goldstein err = PTR_ERR(whiteout); 1210cad218abSAmir Goldstein if (IS_ERR(whiteout)) 1211cad218abSAmir Goldstein goto cleanup_temp; 1212cad218abSAmir Goldstein 1213cad218abSAmir Goldstein err = ovl_is_whiteout(whiteout); 1214cad218abSAmir Goldstein 1215cad218abSAmir Goldstein /* Best effort cleanup of whiteout and temp file */ 1216cad218abSAmir Goldstein if (err) 1217576bb263SChristian Brauner ovl_cleanup(ofs, dir, whiteout); 1218cad218abSAmir Goldstein dput(whiteout); 1219cad218abSAmir Goldstein 1220cad218abSAmir Goldstein cleanup_temp: 1221576bb263SChristian Brauner ovl_cleanup(ofs, dir, temp); 1222cad218abSAmir Goldstein release_dentry_name_snapshot(&name); 1223cad218abSAmir Goldstein dput(temp); 1224cad218abSAmir Goldstein dput(dest); 1225cad218abSAmir Goldstein 1226cad218abSAmir Goldstein out_unlock: 1227cad218abSAmir Goldstein inode_unlock(dir); 1228cad218abSAmir Goldstein 1229cad218abSAmir Goldstein return err; 1230cad218abSAmir Goldstein } 1231cad218abSAmir Goldstein 1232576bb263SChristian Brauner static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, 1233576bb263SChristian Brauner struct dentry *parent, 1234c86243b0SVivek Goyal const char *name, umode_t mode) 1235c86243b0SVivek Goyal { 1236c86243b0SVivek Goyal size_t len = strlen(name); 1237c86243b0SVivek Goyal struct dentry *child; 1238c86243b0SVivek Goyal 1239c86243b0SVivek Goyal inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); 124022f289ceSChristian Brauner child = ovl_lookup_upper(ofs, name, parent, len); 1241c86243b0SVivek Goyal if (!IS_ERR(child) && !child->d_inode) 1242576bb263SChristian Brauner child = ovl_create_real(ofs, parent->d_inode, child, 1243c86243b0SVivek Goyal OVL_CATTR(mode)); 1244c86243b0SVivek Goyal inode_unlock(parent->d_inode); 1245c86243b0SVivek Goyal dput(parent); 1246c86243b0SVivek Goyal 1247c86243b0SVivek Goyal return child; 1248c86243b0SVivek Goyal } 1249c86243b0SVivek Goyal 1250c86243b0SVivek Goyal /* 1251c86243b0SVivek Goyal * Creates $workdir/work/incompat/volatile/dirty file if it is not already 1252c86243b0SVivek Goyal * present. 1253c86243b0SVivek Goyal */ 1254c86243b0SVivek Goyal static int ovl_create_volatile_dirty(struct ovl_fs *ofs) 1255c86243b0SVivek Goyal { 1256c86243b0SVivek Goyal unsigned int ctr; 1257c86243b0SVivek Goyal struct dentry *d = dget(ofs->workbasedir); 1258c86243b0SVivek Goyal static const char *const volatile_path[] = { 1259c86243b0SVivek Goyal OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" 1260c86243b0SVivek Goyal }; 1261c86243b0SVivek Goyal const char *const *name = volatile_path; 1262c86243b0SVivek Goyal 1263c86243b0SVivek Goyal for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { 1264576bb263SChristian Brauner d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); 1265c86243b0SVivek Goyal if (IS_ERR(d)) 1266c86243b0SVivek Goyal return PTR_ERR(d); 1267c86243b0SVivek Goyal } 1268c86243b0SVivek Goyal dput(d); 1269c86243b0SVivek Goyal return 0; 1270c86243b0SVivek Goyal } 1271c86243b0SVivek Goyal 1272146d62e5SAmir Goldstein static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, 12732d343087SAl Viro const struct path *workpath) 12748ed61dc3SMiklos Szeredi { 127508f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 12762b1a7746SMiklos Szeredi struct dentry *workdir; 12772b1a7746SMiklos Szeredi struct file *tmpfile; 1278d80172c2SAmir Goldstein bool rename_whiteout; 1279d80172c2SAmir Goldstein bool d_type; 1280e487d889SAmir Goldstein int fh_type; 12818ed61dc3SMiklos Szeredi int err; 12828ed61dc3SMiklos Szeredi 12832ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 12842ba9d57eSAmir Goldstein if (err) 12852ba9d57eSAmir Goldstein return err; 12862ba9d57eSAmir Goldstein 1287235ce9edSAmir Goldstein workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); 1288235ce9edSAmir Goldstein err = PTR_ERR(workdir); 1289235ce9edSAmir Goldstein if (IS_ERR_OR_NULL(workdir)) 12902ba9d57eSAmir Goldstein goto out; 12918ed61dc3SMiklos Szeredi 1292235ce9edSAmir Goldstein ofs->workdir = workdir; 1293235ce9edSAmir Goldstein 1294146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); 1295146d62e5SAmir Goldstein if (err) 1296146d62e5SAmir Goldstein goto out; 1297146d62e5SAmir Goldstein 12988ed61dc3SMiklos Szeredi /* 12998ed61dc3SMiklos Szeredi * Upper should support d_type, else whiteouts are visible. Given 13008ed61dc3SMiklos Szeredi * workdir and upper are on same fs, we can do iterate_dir() on 13018ed61dc3SMiklos Szeredi * workdir. This check requires successful creation of workdir in 13028ed61dc3SMiklos Szeredi * previous step. 13038ed61dc3SMiklos Szeredi */ 13048ed61dc3SMiklos Szeredi err = ovl_check_d_type_supported(workpath); 13058ed61dc3SMiklos Szeredi if (err < 0) 13062ba9d57eSAmir Goldstein goto out; 13078ed61dc3SMiklos Szeredi 1308d80172c2SAmir Goldstein d_type = err; 1309d80172c2SAmir Goldstein if (!d_type) 13101bd0a3aeSlijiazi pr_warn("upper fs needs to support d_type.\n"); 13118ed61dc3SMiklos Szeredi 13128ed61dc3SMiklos Szeredi /* Check if upper/work fs supports O_TMPFILE */ 13132b1a7746SMiklos Szeredi tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); 13142b1a7746SMiklos Szeredi ofs->tmpfile = !IS_ERR(tmpfile); 1315ad204488SMiklos Szeredi if (ofs->tmpfile) 13162b1a7746SMiklos Szeredi fput(tmpfile); 13178ed61dc3SMiklos Szeredi else 13181bd0a3aeSlijiazi pr_warn("upper fs does not support tmpfile.\n"); 13198ed61dc3SMiklos Szeredi 1320cad218abSAmir Goldstein 1321cad218abSAmir Goldstein /* Check if upper/work fs supports RENAME_WHITEOUT */ 1322576bb263SChristian Brauner err = ovl_check_rename_whiteout(ofs); 1323cad218abSAmir Goldstein if (err < 0) 1324cad218abSAmir Goldstein goto out; 1325cad218abSAmir Goldstein 1326d80172c2SAmir Goldstein rename_whiteout = err; 1327d80172c2SAmir Goldstein if (!rename_whiteout) 1328cad218abSAmir Goldstein pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); 1329cad218abSAmir Goldstein 13308ed61dc3SMiklos Szeredi /* 13312d2f2d73SMiklos Szeredi * Check if upper/work fs supports (trusted|user).overlay.* xattr 13328ed61dc3SMiklos Szeredi */ 1333c914c0e2SAmir Goldstein err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); 13348ed61dc3SMiklos Szeredi if (err) { 1335b10b85feSMiklos Szeredi pr_warn("failed to set xattr on upper\n"); 1336ad204488SMiklos Szeredi ofs->noxattr = true; 1337b0e0f697SAmir Goldstein if (ofs->config.index || ofs->config.metacopy) { 1338a683737bSAmir Goldstein ofs->config.index = false; 1339d5791044SVivek Goyal ofs->config.metacopy = false; 1340b10b85feSMiklos Szeredi pr_warn("...falling back to index=off,metacopy=off.\n"); 1341b0e0f697SAmir Goldstein } 1342b0e0f697SAmir Goldstein /* 1343b0e0f697SAmir Goldstein * xattr support is required for persistent st_ino. 1344b0e0f697SAmir Goldstein * Without persistent st_ino, xino=auto falls back to xino=off. 1345b0e0f697SAmir Goldstein */ 1346b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO) { 1347b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 1348b10b85feSMiklos Szeredi pr_warn("...falling back to xino=off.\n"); 1349b0e0f697SAmir Goldstein } 1350b10b85feSMiklos Szeredi if (err == -EPERM && !ofs->config.userxattr) 1351b10b85feSMiklos Szeredi pr_info("try mounting with 'userxattr' option\n"); 13522ba9d57eSAmir Goldstein err = 0; 13538ed61dc3SMiklos Szeredi } else { 1354c914c0e2SAmir Goldstein ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); 13558ed61dc3SMiklos Szeredi } 13568ed61dc3SMiklos Szeredi 1357d80172c2SAmir Goldstein /* 1358d80172c2SAmir Goldstein * We allowed sub-optimal upper fs configuration and don't want to break 1359d80172c2SAmir Goldstein * users over kernel upgrade, but we never allowed remote upper fs, so 1360d80172c2SAmir Goldstein * we can enforce strict requirements for remote upper fs. 1361d80172c2SAmir Goldstein */ 1362d80172c2SAmir Goldstein if (ovl_dentry_remote(ofs->workdir) && 1363d80172c2SAmir Goldstein (!d_type || !rename_whiteout || ofs->noxattr)) { 1364d80172c2SAmir Goldstein pr_err("upper fs missing required features.\n"); 1365d80172c2SAmir Goldstein err = -EINVAL; 1366d80172c2SAmir Goldstein goto out; 1367d80172c2SAmir Goldstein } 1368d80172c2SAmir Goldstein 1369c86243b0SVivek Goyal /* 1370c86243b0SVivek Goyal * For volatile mount, create a incompat/volatile/dirty file to keep 1371c86243b0SVivek Goyal * track of it. 1372c86243b0SVivek Goyal */ 1373c86243b0SVivek Goyal if (ofs->config.ovl_volatile) { 1374c86243b0SVivek Goyal err = ovl_create_volatile_dirty(ofs); 1375c86243b0SVivek Goyal if (err < 0) { 1376c86243b0SVivek Goyal pr_err("Failed to create volatile/dirty file.\n"); 1377c86243b0SVivek Goyal goto out; 1378c86243b0SVivek Goyal } 1379c86243b0SVivek Goyal } 1380c86243b0SVivek Goyal 13818ed61dc3SMiklos Szeredi /* Check if upper/work fs supports file handles */ 1382e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); 1383e487d889SAmir Goldstein if (ofs->config.index && !fh_type) { 1384ad204488SMiklos Szeredi ofs->config.index = false; 13851bd0a3aeSlijiazi pr_warn("upper fs does not support file handles, falling back to index=off.\n"); 13868ed61dc3SMiklos Szeredi } 13878ed61dc3SMiklos Szeredi 1388e487d889SAmir Goldstein /* Check if upper fs has 32bit inode numbers */ 1389e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 13900f831ec8SAmir Goldstein ofs->xino_mode = -1; 1391e487d889SAmir Goldstein 1392f168f109SAmir Goldstein /* NFS export of r/w mount depends on index */ 1393f168f109SAmir Goldstein if (ofs->config.nfs_export && !ofs->config.index) { 13941bd0a3aeSlijiazi pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); 1395f168f109SAmir Goldstein ofs->config.nfs_export = false; 1396f168f109SAmir Goldstein } 13972ba9d57eSAmir Goldstein out: 13982ba9d57eSAmir Goldstein mnt_drop_write(mnt); 13992ba9d57eSAmir Goldstein return err; 14008ed61dc3SMiklos Szeredi } 14018ed61dc3SMiklos Szeredi 1402146d62e5SAmir Goldstein static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, 14032d343087SAl Viro const struct path *upperpath) 1404520d7c86SMiklos Szeredi { 1405520d7c86SMiklos Szeredi int err; 1406bca44b52SMiklos Szeredi struct path workpath = { }; 1407520d7c86SMiklos Szeredi 1408ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.workdir, &workpath); 1409520d7c86SMiklos Szeredi if (err) 1410520d7c86SMiklos Szeredi goto out; 1411520d7c86SMiklos Szeredi 1412520d7c86SMiklos Szeredi err = -EINVAL; 1413bca44b52SMiklos Szeredi if (upperpath->mnt != workpath.mnt) { 14141bd0a3aeSlijiazi pr_err("workdir and upperdir must reside under the same mount\n"); 1415520d7c86SMiklos Szeredi goto out; 1416520d7c86SMiklos Szeredi } 1417bca44b52SMiklos Szeredi if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { 14181bd0a3aeSlijiazi pr_err("workdir and upperdir must be separate subtrees\n"); 1419520d7c86SMiklos Szeredi goto out; 1420520d7c86SMiklos Szeredi } 1421520d7c86SMiklos Szeredi 14228c25741aSMiklos Szeredi ofs->workbasedir = dget(workpath.dentry); 14238c25741aSMiklos Szeredi 14248c25741aSMiklos Szeredi if (ovl_inuse_trylock(ofs->workbasedir)) { 1425ad204488SMiklos Szeredi ofs->workdir_locked = true; 1426520d7c86SMiklos Szeredi } else { 14270be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "workdir"); 14280be0bfd2SAmir Goldstein if (err) 14290be0bfd2SAmir Goldstein goto out; 1430520d7c86SMiklos Szeredi } 1431520d7c86SMiklos Szeredi 14320be0bfd2SAmir Goldstein err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, 14330be0bfd2SAmir Goldstein "workdir"); 14340be0bfd2SAmir Goldstein if (err) 14350be0bfd2SAmir Goldstein goto out; 14360be0bfd2SAmir Goldstein 1437146d62e5SAmir Goldstein err = ovl_make_workdir(sb, ofs, &workpath); 1438bca44b52SMiklos Szeredi 1439520d7c86SMiklos Szeredi out: 1440bca44b52SMiklos Szeredi path_put(&workpath); 1441bca44b52SMiklos Szeredi 1442520d7c86SMiklos Szeredi return err; 1443520d7c86SMiklos Szeredi } 1444520d7c86SMiklos Szeredi 1445146d62e5SAmir Goldstein static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, 14462d343087SAl Viro struct ovl_entry *oe, const struct path *upperpath) 1447f7e3a7d9SMiklos Szeredi { 144808f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 1449235ce9edSAmir Goldstein struct dentry *indexdir; 1450f7e3a7d9SMiklos Szeredi int err; 1451f7e3a7d9SMiklos Szeredi 14522ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 14532ba9d57eSAmir Goldstein if (err) 14542ba9d57eSAmir Goldstein return err; 14552ba9d57eSAmir Goldstein 1456f7e3a7d9SMiklos Szeredi /* Verify lower root is upper root origin */ 1457610afc0bSMiklos Szeredi err = ovl_verify_origin(ofs, upperpath->dentry, 1458*5522c9c7SAmir Goldstein ovl_lowerstack(oe)->dentry, true); 1459f7e3a7d9SMiklos Szeredi if (err) { 14601bd0a3aeSlijiazi pr_err("failed to verify upper root origin\n"); 1461f7e3a7d9SMiklos Szeredi goto out; 1462f7e3a7d9SMiklos Szeredi } 1463f7e3a7d9SMiklos Szeredi 146420396365SAmir Goldstein /* index dir will act also as workdir */ 146520396365SAmir Goldstein iput(ofs->workdir_trap); 146620396365SAmir Goldstein ofs->workdir_trap = NULL; 146720396365SAmir Goldstein dput(ofs->workdir); 1468470c1563SAmir Goldstein ofs->workdir = NULL; 1469235ce9edSAmir Goldstein indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); 1470235ce9edSAmir Goldstein if (IS_ERR(indexdir)) { 1471235ce9edSAmir Goldstein err = PTR_ERR(indexdir); 1472235ce9edSAmir Goldstein } else if (indexdir) { 1473235ce9edSAmir Goldstein ofs->indexdir = indexdir; 1474235ce9edSAmir Goldstein ofs->workdir = dget(indexdir); 147520396365SAmir Goldstein 1476146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, 1477146d62e5SAmir Goldstein "indexdir"); 1478146d62e5SAmir Goldstein if (err) 1479146d62e5SAmir Goldstein goto out; 1480146d62e5SAmir Goldstein 1481ad1d615cSAmir Goldstein /* 1482ad1d615cSAmir Goldstein * Verify upper root is exclusively associated with index dir. 14832d2f2d73SMiklos Szeredi * Older kernels stored upper fh in ".overlay.origin" 1484ad1d615cSAmir Goldstein * xattr. If that xattr exists, verify that it is a match to 1485ad1d615cSAmir Goldstein * upper dir file handle. In any case, verify or set xattr 14862d2f2d73SMiklos Szeredi * ".overlay.upper" to indicate that index may have 1487ad1d615cSAmir Goldstein * directory entries. 1488ad1d615cSAmir Goldstein */ 1489610afc0bSMiklos Szeredi if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { 1490610afc0bSMiklos Szeredi err = ovl_verify_set_fh(ofs, ofs->indexdir, 1491610afc0bSMiklos Szeredi OVL_XATTR_ORIGIN, 1492ad1d615cSAmir Goldstein upperpath->dentry, true, false); 1493f7e3a7d9SMiklos Szeredi if (err) 14941bd0a3aeSlijiazi pr_err("failed to verify index dir 'origin' xattr\n"); 1495ad1d615cSAmir Goldstein } 1496610afc0bSMiklos Szeredi err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, 1497610afc0bSMiklos Szeredi true); 1498ad1d615cSAmir Goldstein if (err) 14991bd0a3aeSlijiazi pr_err("failed to verify index dir 'upper' xattr\n"); 1500f7e3a7d9SMiklos Szeredi 1501f7e3a7d9SMiklos Szeredi /* Cleanup bad/stale/orphan index entries */ 1502f7e3a7d9SMiklos Szeredi if (!err) 15031eff1a1dSAmir Goldstein err = ovl_indexdir_cleanup(ofs); 1504f7e3a7d9SMiklos Szeredi } 1505ad204488SMiklos Szeredi if (err || !ofs->indexdir) 15061bd0a3aeSlijiazi pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); 1507f7e3a7d9SMiklos Szeredi 1508f7e3a7d9SMiklos Szeredi out: 15092ba9d57eSAmir Goldstein mnt_drop_write(mnt); 1510f7e3a7d9SMiklos Szeredi return err; 1511f7e3a7d9SMiklos Szeredi } 1512f7e3a7d9SMiklos Szeredi 15139df085f3SAmir Goldstein static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) 15145148626bSAmir Goldstein { 15155148626bSAmir Goldstein unsigned int i; 15169df085f3SAmir Goldstein 151708f4c7c8SMiklos Szeredi if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) 15189df085f3SAmir Goldstein return true; 15199df085f3SAmir Goldstein 1520a888db31SAmir Goldstein /* 1521a888db31SAmir Goldstein * We allow using single lower with null uuid for index and nfs_export 1522a888db31SAmir Goldstein * for example to support those features with single lower squashfs. 1523a888db31SAmir Goldstein * To avoid regressions in setups of overlay with re-formatted lower 1524a888db31SAmir Goldstein * squashfs, do not allow decoding origin with lower null uuid unless 1525a888db31SAmir Goldstein * user opted-in to one of the new features that require following the 1526a888db31SAmir Goldstein * lower inode of non-dir upper. 1527a888db31SAmir Goldstein */ 1528ca45275cSVyacheslav Yurkov if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) 1529a888db31SAmir Goldstein return false; 1530a888db31SAmir Goldstein 15311b81ddddSAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 15329df085f3SAmir Goldstein /* 15339df085f3SAmir Goldstein * We use uuid to associate an overlay lower file handle with a 15349df085f3SAmir Goldstein * lower layer, so we can accept lower fs with null uuid as long 15359df085f3SAmir Goldstein * as all lower layers with null uuid are on the same fs. 15367e63c87fSAmir Goldstein * if we detect multiple lower fs with the same uuid, we 15377e63c87fSAmir Goldstein * disable lower file handle decoding on all of them. 15389df085f3SAmir Goldstein */ 15391b81ddddSAmir Goldstein if (ofs->fs[i].is_lower && 15401b81ddddSAmir Goldstein uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { 154107f1e596SAmir Goldstein ofs->fs[i].bad_uuid = true; 15429df085f3SAmir Goldstein return false; 15439df085f3SAmir Goldstein } 15447e63c87fSAmir Goldstein } 15459df085f3SAmir Goldstein return true; 15469df085f3SAmir Goldstein } 15479df085f3SAmir Goldstein 15489df085f3SAmir Goldstein /* Get a unique fsid for the layer */ 15499df085f3SAmir Goldstein static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) 15509df085f3SAmir Goldstein { 15519df085f3SAmir Goldstein struct super_block *sb = path->mnt->mnt_sb; 15529df085f3SAmir Goldstein unsigned int i; 15535148626bSAmir Goldstein dev_t dev; 15545148626bSAmir Goldstein int err; 15557e63c87fSAmir Goldstein bool bad_uuid = false; 1556b0e0f697SAmir Goldstein bool warn = false; 15575148626bSAmir Goldstein 155807f1e596SAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 155907f1e596SAmir Goldstein if (ofs->fs[i].sb == sb) 156007f1e596SAmir Goldstein return i; 15615148626bSAmir Goldstein } 15625148626bSAmir Goldstein 15639df085f3SAmir Goldstein if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { 15647e63c87fSAmir Goldstein bad_uuid = true; 1565b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO) { 1566b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 1567b0e0f697SAmir Goldstein warn = true; 1568b0e0f697SAmir Goldstein } 15697e63c87fSAmir Goldstein if (ofs->config.index || ofs->config.nfs_export) { 15709df085f3SAmir Goldstein ofs->config.index = false; 15719df085f3SAmir Goldstein ofs->config.nfs_export = false; 1572b0e0f697SAmir Goldstein warn = true; 1573b0e0f697SAmir Goldstein } 1574b0e0f697SAmir Goldstein if (warn) { 1575b0e0f697SAmir Goldstein pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", 15767e63c87fSAmir Goldstein uuid_is_null(&sb->s_uuid) ? "null" : 15777e63c87fSAmir Goldstein "conflicting", 1578b0e0f697SAmir Goldstein path->dentry, ovl_xino_str[ofs->config.xino]); 15799df085f3SAmir Goldstein } 15807e63c87fSAmir Goldstein } 15819df085f3SAmir Goldstein 15825148626bSAmir Goldstein err = get_anon_bdev(&dev); 15835148626bSAmir Goldstein if (err) { 15841bd0a3aeSlijiazi pr_err("failed to get anonymous bdev for lowerpath\n"); 15855148626bSAmir Goldstein return err; 15865148626bSAmir Goldstein } 15875148626bSAmir Goldstein 158807f1e596SAmir Goldstein ofs->fs[ofs->numfs].sb = sb; 158907f1e596SAmir Goldstein ofs->fs[ofs->numfs].pseudo_dev = dev; 159007f1e596SAmir Goldstein ofs->fs[ofs->numfs].bad_uuid = bad_uuid; 15915148626bSAmir Goldstein 159207f1e596SAmir Goldstein return ofs->numfs++; 15935148626bSAmir Goldstein } 15945148626bSAmir Goldstein 159594375f9dSAmir Goldstein static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, 1596b8e42a65SMiklos Szeredi struct path *stack, unsigned int numlower, 1597b8e42a65SMiklos Szeredi struct ovl_layer *layers) 1598520d7c86SMiklos Szeredi { 1599520d7c86SMiklos Szeredi int err; 1600520d7c86SMiklos Szeredi unsigned int i; 1601520d7c86SMiklos Szeredi 1602520d7c86SMiklos Szeredi err = -ENOMEM; 160307f1e596SAmir Goldstein ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); 160407f1e596SAmir Goldstein if (ofs->fs == NULL) 16055148626bSAmir Goldstein goto out; 16065148626bSAmir Goldstein 160707f1e596SAmir Goldstein /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ 160807f1e596SAmir Goldstein ofs->numfs++; 160907f1e596SAmir Goldstein 161007f1e596SAmir Goldstein /* 1611b7bf9908SAmir Goldstein * All lower layers that share the same fs as upper layer, use the same 1612b7bf9908SAmir Goldstein * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower 1613b7bf9908SAmir Goldstein * only overlay to simplify ovl_fs_free(). 16141b81ddddSAmir Goldstein * is_lower will be set if upper fs is shared with a lower layer. 161507f1e596SAmir Goldstein */ 1616b7bf9908SAmir Goldstein err = get_anon_bdev(&ofs->fs[0].pseudo_dev); 1617b7bf9908SAmir Goldstein if (err) { 1618b7bf9908SAmir Goldstein pr_err("failed to get anonymous bdev for upper fs\n"); 1619b7bf9908SAmir Goldstein goto out; 1620b7bf9908SAmir Goldstein } 1621b7bf9908SAmir Goldstein 162208f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 162308f4c7c8SMiklos Szeredi ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; 16241b81ddddSAmir Goldstein ofs->fs[0].is_lower = false; 162507f1e596SAmir Goldstein } 162607f1e596SAmir Goldstein 1627520d7c86SMiklos Szeredi for (i = 0; i < numlower; i++) { 1628520d7c86SMiklos Szeredi struct vfsmount *mnt; 1629146d62e5SAmir Goldstein struct inode *trap; 16305148626bSAmir Goldstein int fsid; 1631520d7c86SMiklos Szeredi 16329df085f3SAmir Goldstein err = fsid = ovl_get_fsid(ofs, &stack[i]); 16335148626bSAmir Goldstein if (err < 0) 1634520d7c86SMiklos Szeredi goto out; 1635520d7c86SMiklos Szeredi 163624f14009Syoungjun /* 163724f14009Syoungjun * Check if lower root conflicts with this overlay layers before 163824f14009Syoungjun * checking if it is in-use as upperdir/workdir of "another" 163924f14009Syoungjun * mount, because we do not bother to check in ovl_is_inuse() if 164024f14009Syoungjun * the upperdir/workdir is in fact in-use by our 164124f14009Syoungjun * upperdir/workdir. 164224f14009Syoungjun */ 1643146d62e5SAmir Goldstein err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); 1644146d62e5SAmir Goldstein if (err) 1645146d62e5SAmir Goldstein goto out; 1646146d62e5SAmir Goldstein 16470be0bfd2SAmir Goldstein if (ovl_is_inuse(stack[i].dentry)) { 16480be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "lowerdir"); 164924f14009Syoungjun if (err) { 165024f14009Syoungjun iput(trap); 16510be0bfd2SAmir Goldstein goto out; 16520be0bfd2SAmir Goldstein } 165324f14009Syoungjun } 16540be0bfd2SAmir Goldstein 1655520d7c86SMiklos Szeredi mnt = clone_private_mount(&stack[i]); 1656520d7c86SMiklos Szeredi err = PTR_ERR(mnt); 1657520d7c86SMiklos Szeredi if (IS_ERR(mnt)) { 16581bd0a3aeSlijiazi pr_err("failed to clone lowerpath\n"); 1659146d62e5SAmir Goldstein iput(trap); 1660520d7c86SMiklos Szeredi goto out; 1661520d7c86SMiklos Szeredi } 16625148626bSAmir Goldstein 1663520d7c86SMiklos Szeredi /* 1664520d7c86SMiklos Szeredi * Make lower layers R/O. That way fchmod/fchown on lower file 1665520d7c86SMiklos Szeredi * will fail instead of modifying lower fs. 1666520d7c86SMiklos Szeredi */ 1667520d7c86SMiklos Szeredi mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; 1668520d7c86SMiklos Szeredi 166913464165SMiklos Szeredi layers[ofs->numlayer].trap = trap; 167013464165SMiklos Szeredi layers[ofs->numlayer].mnt = mnt; 167113464165SMiklos Szeredi layers[ofs->numlayer].idx = ofs->numlayer; 167213464165SMiklos Szeredi layers[ofs->numlayer].fsid = fsid; 167313464165SMiklos Szeredi layers[ofs->numlayer].fs = &ofs->fs[fsid]; 167494375f9dSAmir Goldstein ofs->numlayer++; 16751b81ddddSAmir Goldstein ofs->fs[fsid].is_lower = true; 1676520d7c86SMiklos Szeredi } 1677e487d889SAmir Goldstein 1678795939a9SAmir Goldstein /* 1679795939a9SAmir Goldstein * When all layers on same fs, overlay can use real inode numbers. 1680926e94d7SAmir Goldstein * With mount option "xino=<on|auto>", mounter declares that there are 1681926e94d7SAmir Goldstein * enough free high bits in underlying fs to hold the unique fsid. 1682795939a9SAmir Goldstein * If overlayfs does encounter underlying inodes using the high xino 1683795939a9SAmir Goldstein * bits reserved for fsid, it emits a warning and uses the original 1684dfe51d47SAmir Goldstein * inode number or a non persistent inode number allocated from a 1685dfe51d47SAmir Goldstein * dedicated range. 1686795939a9SAmir Goldstein */ 168708f4c7c8SMiklos Szeredi if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { 16880f831ec8SAmir Goldstein if (ofs->config.xino == OVL_XINO_ON) 16890f831ec8SAmir Goldstein pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); 16900f831ec8SAmir Goldstein ofs->xino_mode = 0; 169153afcd31SAmir Goldstein } else if (ofs->config.xino == OVL_XINO_OFF) { 169253afcd31SAmir Goldstein ofs->xino_mode = -1; 1693926e94d7SAmir Goldstein } else if (ofs->xino_mode < 0) { 1694795939a9SAmir Goldstein /* 169507f1e596SAmir Goldstein * This is a roundup of number of bits needed for encoding 1696dfe51d47SAmir Goldstein * fsid, where fsid 0 is reserved for upper fs (even with 1697dfe51d47SAmir Goldstein * lower only overlay) +1 extra bit is reserved for the non 1698dfe51d47SAmir Goldstein * persistent inode number range that is used for resolving 1699dfe51d47SAmir Goldstein * xino lower bits overflow. 1700795939a9SAmir Goldstein */ 1701dfe51d47SAmir Goldstein BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); 1702dfe51d47SAmir Goldstein ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; 1703795939a9SAmir Goldstein } 1704795939a9SAmir Goldstein 17050f831ec8SAmir Goldstein if (ofs->xino_mode > 0) { 17061bd0a3aeSlijiazi pr_info("\"xino\" feature enabled using %d upper inode bits.\n", 17070f831ec8SAmir Goldstein ofs->xino_mode); 1708795939a9SAmir Goldstein } 1709e487d889SAmir Goldstein 1710520d7c86SMiklos Szeredi err = 0; 1711520d7c86SMiklos Szeredi out: 1712520d7c86SMiklos Szeredi return err; 1713520d7c86SMiklos Szeredi } 1714520d7c86SMiklos Szeredi 17154155c10aSMiklos Szeredi static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, 1716b8e42a65SMiklos Szeredi const char *lower, unsigned int numlower, 1717b8e42a65SMiklos Szeredi struct ovl_fs *ofs, struct ovl_layer *layers) 171853dbb0b4SMiklos Szeredi { 171953dbb0b4SMiklos Szeredi int err; 17204155c10aSMiklos Szeredi struct path *stack = NULL; 1721*5522c9c7SAmir Goldstein struct ovl_path *lowerstack; 1722b8e42a65SMiklos Szeredi unsigned int i; 17234155c10aSMiklos Szeredi struct ovl_entry *oe; 172453dbb0b4SMiklos Szeredi 1725b8e42a65SMiklos Szeredi if (!ofs->config.upperdir && numlower == 1) { 17261bd0a3aeSlijiazi pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); 1727b8e42a65SMiklos Szeredi return ERR_PTR(-EINVAL); 172853dbb0b4SMiklos Szeredi } 172953dbb0b4SMiklos Szeredi 1730b8e42a65SMiklos Szeredi stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); 173153dbb0b4SMiklos Szeredi if (!stack) 1732b8e42a65SMiklos Szeredi return ERR_PTR(-ENOMEM); 173353dbb0b4SMiklos Szeredi 173453dbb0b4SMiklos Szeredi err = -EINVAL; 1735b8e42a65SMiklos Szeredi for (i = 0; i < numlower; i++) { 1736b8e42a65SMiklos Szeredi err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); 173753dbb0b4SMiklos Szeredi if (err) 17384155c10aSMiklos Szeredi goto out_err; 173953dbb0b4SMiklos Szeredi 174053dbb0b4SMiklos Szeredi lower = strchr(lower, '\0') + 1; 174153dbb0b4SMiklos Szeredi } 174253dbb0b4SMiklos Szeredi 174353dbb0b4SMiklos Szeredi err = -EINVAL; 174453dbb0b4SMiklos Szeredi sb->s_stack_depth++; 174553dbb0b4SMiklos Szeredi if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { 17461bd0a3aeSlijiazi pr_err("maximum fs stacking depth exceeded\n"); 17474155c10aSMiklos Szeredi goto out_err; 174853dbb0b4SMiklos Szeredi } 174953dbb0b4SMiklos Szeredi 1750b8e42a65SMiklos Szeredi err = ovl_get_layers(sb, ofs, stack, numlower, layers); 17514155c10aSMiklos Szeredi if (err) 17524155c10aSMiklos Szeredi goto out_err; 17534155c10aSMiklos Szeredi 17544155c10aSMiklos Szeredi err = -ENOMEM; 17554155c10aSMiklos Szeredi oe = ovl_alloc_entry(numlower); 17564155c10aSMiklos Szeredi if (!oe) 17574155c10aSMiklos Szeredi goto out_err; 17584155c10aSMiklos Szeredi 1759*5522c9c7SAmir Goldstein lowerstack = ovl_lowerstack(oe); 17604155c10aSMiklos Szeredi for (i = 0; i < numlower; i++) { 1761*5522c9c7SAmir Goldstein lowerstack[i].dentry = dget(stack[i].dentry); 1762*5522c9c7SAmir Goldstein lowerstack[i].layer = &ofs->layers[i+1]; 17634155c10aSMiklos Szeredi } 176453dbb0b4SMiklos Szeredi 176553dbb0b4SMiklos Szeredi out: 176653dbb0b4SMiklos Szeredi for (i = 0; i < numlower; i++) 176753dbb0b4SMiklos Szeredi path_put(&stack[i]); 176853dbb0b4SMiklos Szeredi kfree(stack); 17694155c10aSMiklos Szeredi 17704155c10aSMiklos Szeredi return oe; 17714155c10aSMiklos Szeredi 17724155c10aSMiklos Szeredi out_err: 17734155c10aSMiklos Szeredi oe = ERR_PTR(err); 177453dbb0b4SMiklos Szeredi goto out; 177553dbb0b4SMiklos Szeredi } 177653dbb0b4SMiklos Szeredi 1777146d62e5SAmir Goldstein /* 1778146d62e5SAmir Goldstein * Check if this layer root is a descendant of: 1779146d62e5SAmir Goldstein * - another layer of this overlayfs instance 1780146d62e5SAmir Goldstein * - upper/work dir of any overlayfs instance 1781146d62e5SAmir Goldstein */ 17820be0bfd2SAmir Goldstein static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, 1783708fa015SMiklos Szeredi struct dentry *dentry, const char *name, 1784708fa015SMiklos Szeredi bool is_lower) 1785146d62e5SAmir Goldstein { 17869179c21dSMiklos Szeredi struct dentry *next = dentry, *parent; 1787146d62e5SAmir Goldstein int err = 0; 1788146d62e5SAmir Goldstein 17899179c21dSMiklos Szeredi if (!dentry) 1790146d62e5SAmir Goldstein return 0; 1791146d62e5SAmir Goldstein 1792146d62e5SAmir Goldstein parent = dget_parent(next); 17939179c21dSMiklos Szeredi 17949179c21dSMiklos Szeredi /* Walk back ancestors to root (inclusive) looking for traps */ 17959179c21dSMiklos Szeredi while (!err && parent != next) { 1796708fa015SMiklos Szeredi if (is_lower && ovl_lookup_trap_inode(sb, parent)) { 1797146d62e5SAmir Goldstein err = -ELOOP; 17981bd0a3aeSlijiazi pr_err("overlapping %s path\n", name); 17990be0bfd2SAmir Goldstein } else if (ovl_is_inuse(parent)) { 18000be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, name); 1801146d62e5SAmir Goldstein } 1802146d62e5SAmir Goldstein next = parent; 18039179c21dSMiklos Szeredi parent = dget_parent(next); 18049179c21dSMiklos Szeredi dput(next); 1805146d62e5SAmir Goldstein } 1806146d62e5SAmir Goldstein 18079179c21dSMiklos Szeredi dput(parent); 1808146d62e5SAmir Goldstein 1809146d62e5SAmir Goldstein return err; 1810146d62e5SAmir Goldstein } 1811146d62e5SAmir Goldstein 1812146d62e5SAmir Goldstein /* 1813146d62e5SAmir Goldstein * Check if any of the layers or work dirs overlap. 1814146d62e5SAmir Goldstein */ 1815146d62e5SAmir Goldstein static int ovl_check_overlapping_layers(struct super_block *sb, 1816146d62e5SAmir Goldstein struct ovl_fs *ofs) 1817146d62e5SAmir Goldstein { 1818146d62e5SAmir Goldstein int i, err; 1819146d62e5SAmir Goldstein 182008f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 182108f4c7c8SMiklos Szeredi err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, 1822708fa015SMiklos Szeredi "upperdir", false); 1823146d62e5SAmir Goldstein if (err) 1824146d62e5SAmir Goldstein return err; 1825146d62e5SAmir Goldstein 1826146d62e5SAmir Goldstein /* 1827146d62e5SAmir Goldstein * Checking workbasedir avoids hitting ovl_is_inuse(parent) of 1828146d62e5SAmir Goldstein * this instance and covers overlapping work and index dirs, 1829146d62e5SAmir Goldstein * unless work or index dir have been moved since created inside 1830146d62e5SAmir Goldstein * workbasedir. In that case, we already have their traps in 1831146d62e5SAmir Goldstein * inode cache and we will catch that case on lookup. 1832146d62e5SAmir Goldstein */ 1833708fa015SMiklos Szeredi err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", 1834708fa015SMiklos Szeredi false); 1835146d62e5SAmir Goldstein if (err) 1836146d62e5SAmir Goldstein return err; 1837146d62e5SAmir Goldstein } 1838146d62e5SAmir Goldstein 183994375f9dSAmir Goldstein for (i = 1; i < ofs->numlayer; i++) { 18400be0bfd2SAmir Goldstein err = ovl_check_layer(sb, ofs, 184194375f9dSAmir Goldstein ofs->layers[i].mnt->mnt_root, 1842708fa015SMiklos Szeredi "lowerdir", true); 1843146d62e5SAmir Goldstein if (err) 1844146d62e5SAmir Goldstein return err; 1845146d62e5SAmir Goldstein } 1846146d62e5SAmir Goldstein 1847146d62e5SAmir Goldstein return 0; 1848146d62e5SAmir Goldstein } 1849146d62e5SAmir Goldstein 18502effc5c2SAmir Goldstein static struct dentry *ovl_get_root(struct super_block *sb, 18512effc5c2SAmir Goldstein struct dentry *upperdentry, 18522effc5c2SAmir Goldstein struct ovl_entry *oe) 18532effc5c2SAmir Goldstein { 18542effc5c2SAmir Goldstein struct dentry *root; 1855*5522c9c7SAmir Goldstein struct ovl_path *lowerpath = ovl_lowerstack(oe); 185662c832edSAmir Goldstein unsigned long ino = d_inode(lowerpath->dentry)->i_ino; 185762c832edSAmir Goldstein int fsid = lowerpath->layer->fsid; 185862c832edSAmir Goldstein struct ovl_inode_params oip = { 185962c832edSAmir Goldstein .upperdentry = upperdentry, 186062c832edSAmir Goldstein .lowerpath = lowerpath, 186162c832edSAmir Goldstein }; 18622effc5c2SAmir Goldstein 18632effc5c2SAmir Goldstein root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); 18642effc5c2SAmir Goldstein if (!root) 18652effc5c2SAmir Goldstein return NULL; 18662effc5c2SAmir Goldstein 18672effc5c2SAmir Goldstein root->d_fsdata = oe; 18682effc5c2SAmir Goldstein 18692effc5c2SAmir Goldstein if (upperdentry) { 187062c832edSAmir Goldstein /* Root inode uses upper st_ino/i_ino */ 187162c832edSAmir Goldstein ino = d_inode(upperdentry)->i_ino; 187262c832edSAmir Goldstein fsid = 0; 18732effc5c2SAmir Goldstein ovl_dentry_set_upper_alias(root); 1874610afc0bSMiklos Szeredi if (ovl_is_impuredir(sb, upperdentry)) 18752effc5c2SAmir Goldstein ovl_set_flag(OVL_IMPURE, d_inode(root)); 18762effc5c2SAmir Goldstein } 18772effc5c2SAmir Goldstein 18782effc5c2SAmir Goldstein /* Root is always merge -> can have whiteouts */ 18792effc5c2SAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); 18802effc5c2SAmir Goldstein ovl_dentry_set_flag(OVL_E_CONNECTED, root); 18812effc5c2SAmir Goldstein ovl_set_upperdata(d_inode(root)); 188262c832edSAmir Goldstein ovl_inode_init(d_inode(root), &oip, ino, fsid); 1883b07d5cc9SAmir Goldstein ovl_dentry_init_flags(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); 18842effc5c2SAmir Goldstein 18852effc5c2SAmir Goldstein return root; 18862effc5c2SAmir Goldstein } 18872effc5c2SAmir Goldstein 1888e9be9d5eSMiklos Szeredi static int ovl_fill_super(struct super_block *sb, void *data, int silent) 1889e9be9d5eSMiklos Szeredi { 189033006cdfSKees Cook struct path upperpath = { }; 1891e9be9d5eSMiklos Szeredi struct dentry *root_dentry; 18924155c10aSMiklos Szeredi struct ovl_entry *oe; 1893ad204488SMiklos Szeredi struct ovl_fs *ofs; 1894b8e42a65SMiklos Szeredi struct ovl_layer *layers; 189551f8f3c4SKonstantin Khlebnikov struct cred *cred; 1896b8e42a65SMiklos Szeredi char *splitlower = NULL; 1897b8e42a65SMiklos Szeredi unsigned int numlower; 1898e9be9d5eSMiklos Szeredi int err; 1899e9be9d5eSMiklos Szeredi 19009efb069dSMiklos Szeredi err = -EIO; 19019efb069dSMiklos Szeredi if (WARN_ON(sb->s_user_ns != current_user_ns())) 19029efb069dSMiklos Szeredi goto out; 19039efb069dSMiklos Szeredi 1904f4288844SMiklos Szeredi sb->s_d_op = &ovl_dentry_operations; 1905f4288844SMiklos Szeredi 1906f45827e8SErez Zadok err = -ENOMEM; 1907ad204488SMiklos Szeredi ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); 1908ad204488SMiklos Szeredi if (!ofs) 1909e9be9d5eSMiklos Szeredi goto out; 1910e9be9d5eSMiklos Szeredi 1911d7b49b10SChengguang Xu err = -ENOMEM; 1912ad204488SMiklos Szeredi ofs->creator_cred = cred = prepare_creds(); 1913c6fe6254SMiklos Szeredi if (!cred) 1914c6fe6254SMiklos Szeredi goto out_err; 1915c6fe6254SMiklos Szeredi 1916c21c839bSChengguang Xu /* Is there a reason anyone would want not to share whiteouts? */ 1917c21c839bSChengguang Xu ofs->share_whiteout = true; 1918c21c839bSChengguang Xu 1919ad204488SMiklos Szeredi ofs->config.index = ovl_index_def; 19205830fb6bSPavel Tikhomirov ofs->config.uuid = true; 1921f168f109SAmir Goldstein ofs->config.nfs_export = ovl_nfs_export_def; 1922795939a9SAmir Goldstein ofs->config.xino = ovl_xino_def(); 1923d5791044SVivek Goyal ofs->config.metacopy = ovl_metacopy_def; 1924ad204488SMiklos Szeredi err = ovl_parse_opt((char *) data, &ofs->config); 1925f45827e8SErez Zadok if (err) 1926a9075cdbSMiklos Szeredi goto out_err; 1927f45827e8SErez Zadok 1928e9be9d5eSMiklos Szeredi err = -EINVAL; 1929ad204488SMiklos Szeredi if (!ofs->config.lowerdir) { 193007f2af7bSKonstantin Khlebnikov if (!silent) 19311bd0a3aeSlijiazi pr_err("missing 'lowerdir'\n"); 1932a9075cdbSMiklos Szeredi goto out_err; 193353a08cb9SMiklos Szeredi } 193453a08cb9SMiklos Szeredi 1935b8e42a65SMiklos Szeredi err = -ENOMEM; 1936b8e42a65SMiklos Szeredi splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); 1937b8e42a65SMiklos Szeredi if (!splitlower) 1938b8e42a65SMiklos Szeredi goto out_err; 1939b8e42a65SMiklos Szeredi 1940d7b49b10SChengguang Xu err = -EINVAL; 1941b8e42a65SMiklos Szeredi numlower = ovl_split_lowerdirs(splitlower); 1942b8e42a65SMiklos Szeredi if (numlower > OVL_MAX_STACK) { 1943b8e42a65SMiklos Szeredi pr_err("too many lower directories, limit is %d\n", 1944b8e42a65SMiklos Szeredi OVL_MAX_STACK); 1945b8e42a65SMiklos Szeredi goto out_err; 1946b8e42a65SMiklos Szeredi } 1947b8e42a65SMiklos Szeredi 1948d7b49b10SChengguang Xu err = -ENOMEM; 1949b8e42a65SMiklos Szeredi layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); 1950b8e42a65SMiklos Szeredi if (!layers) 1951b8e42a65SMiklos Szeredi goto out_err; 1952b8e42a65SMiklos Szeredi 1953b8e42a65SMiklos Szeredi ofs->layers = layers; 1954b8e42a65SMiklos Szeredi /* Layer 0 is reserved for upper even if there's no upper */ 1955b8e42a65SMiklos Szeredi ofs->numlayer = 1; 1956b8e42a65SMiklos Szeredi 195753a08cb9SMiklos Szeredi sb->s_stack_depth = 0; 1958cf9a6784SMiklos Szeredi sb->s_maxbytes = MAX_LFS_FILESIZE; 19594d314f78SAmir Goldstein atomic_long_set(&ofs->last_ino, 1); 19604f119628SWilliam Dean /* Assume underlying fs uses 32bit inodes unless proven otherwise */ 196153afcd31SAmir Goldstein if (ofs->config.xino != OVL_XINO_OFF) { 19620f831ec8SAmir Goldstein ofs->xino_mode = BITS_PER_LONG - 32; 196353afcd31SAmir Goldstein if (!ofs->xino_mode) { 196453afcd31SAmir Goldstein pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); 196553afcd31SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 196653afcd31SAmir Goldstein } 196753afcd31SAmir Goldstein } 1968795939a9SAmir Goldstein 1969146d62e5SAmir Goldstein /* alloc/destroy_inode needed for setting up traps in inode cache */ 1970146d62e5SAmir Goldstein sb->s_op = &ovl_super_operations; 1971146d62e5SAmir Goldstein 1972ad204488SMiklos Szeredi if (ofs->config.upperdir) { 1973335d3fc5SSargun Dhillon struct super_block *upper_sb; 1974335d3fc5SSargun Dhillon 1975d7b49b10SChengguang Xu err = -EINVAL; 1976ad204488SMiklos Szeredi if (!ofs->config.workdir) { 19771bd0a3aeSlijiazi pr_err("missing 'workdir'\n"); 1978a9075cdbSMiklos Szeredi goto out_err; 1979e9be9d5eSMiklos Szeredi } 1980e9be9d5eSMiklos Szeredi 1981b8e42a65SMiklos Szeredi err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); 198221a3b317SMiklos Szeredi if (err) 1983a9075cdbSMiklos Szeredi goto out_err; 1984d719e8f2SMiklos Szeredi 1985335d3fc5SSargun Dhillon upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 1986335d3fc5SSargun Dhillon if (!ovl_should_sync(ofs)) { 1987335d3fc5SSargun Dhillon ofs->errseq = errseq_sample(&upper_sb->s_wb_err); 1988335d3fc5SSargun Dhillon if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { 1989335d3fc5SSargun Dhillon err = -EIO; 1990335d3fc5SSargun Dhillon pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); 1991335d3fc5SSargun Dhillon goto out_err; 1992335d3fc5SSargun Dhillon } 1993335d3fc5SSargun Dhillon } 1994335d3fc5SSargun Dhillon 1995146d62e5SAmir Goldstein err = ovl_get_workdir(sb, ofs, &upperpath); 19968ed61dc3SMiklos Szeredi if (err) 1997a9075cdbSMiklos Szeredi goto out_err; 1998c6fe6254SMiklos Szeredi 1999ad204488SMiklos Szeredi if (!ofs->workdir) 20001751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 20016e88256eSMiklos Szeredi 2002335d3fc5SSargun Dhillon sb->s_stack_depth = upper_sb->s_stack_depth; 2003335d3fc5SSargun Dhillon sb->s_time_gran = upper_sb->s_time_gran; 200421765194SVivek Goyal } 2005b8e42a65SMiklos Szeredi oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); 20064155c10aSMiklos Szeredi err = PTR_ERR(oe); 20074155c10aSMiklos Szeredi if (IS_ERR(oe)) 2008a9075cdbSMiklos Szeredi goto out_err; 2009e9be9d5eSMiklos Szeredi 201071cbad7eShujianyang /* If the upper fs is nonexistent, we mark overlayfs r/o too */ 201108f4c7c8SMiklos Szeredi if (!ovl_upper_mnt(ofs)) 20121751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 2013e9be9d5eSMiklos Szeredi 20145830fb6bSPavel Tikhomirov if (!ofs->config.uuid && ofs->numfs > 1) { 20155830fb6bSPavel Tikhomirov pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); 20165830fb6bSPavel Tikhomirov ofs->config.uuid = true; 20175830fb6bSPavel Tikhomirov } 20185830fb6bSPavel Tikhomirov 2019470c1563SAmir Goldstein if (!ovl_force_readonly(ofs) && ofs->config.index) { 2020146d62e5SAmir Goldstein err = ovl_get_indexdir(sb, ofs, oe, &upperpath); 202154fb347eSAmir Goldstein if (err) 20224155c10aSMiklos Szeredi goto out_free_oe; 20236e88256eSMiklos Szeredi 2024972d0093SAmir Goldstein /* Force r/o mount with no index dir */ 202520396365SAmir Goldstein if (!ofs->indexdir) 20261751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 202702bcd157SAmir Goldstein } 202802bcd157SAmir Goldstein 2029146d62e5SAmir Goldstein err = ovl_check_overlapping_layers(sb, ofs); 2030146d62e5SAmir Goldstein if (err) 2031146d62e5SAmir Goldstein goto out_free_oe; 2032146d62e5SAmir Goldstein 2033972d0093SAmir Goldstein /* Show index=off in /proc/mounts for forced r/o mount */ 2034f168f109SAmir Goldstein if (!ofs->indexdir) { 2035ad204488SMiklos Szeredi ofs->config.index = false; 203608f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { 20371bd0a3aeSlijiazi pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); 2038f168f109SAmir Goldstein ofs->config.nfs_export = false; 2039f168f109SAmir Goldstein } 2040f168f109SAmir Goldstein } 204102bcd157SAmir Goldstein 2042d5791044SVivek Goyal if (ofs->config.metacopy && ofs->config.nfs_export) { 20431bd0a3aeSlijiazi pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); 2044d5791044SVivek Goyal ofs->config.nfs_export = false; 2045d5791044SVivek Goyal } 2046d5791044SVivek Goyal 20478383f174SAmir Goldstein if (ofs->config.nfs_export) 20488383f174SAmir Goldstein sb->s_export_op = &ovl_export_operations; 20498383f174SAmir Goldstein 205051f8f3c4SKonstantin Khlebnikov /* Never override disk quota limits or use reserved space */ 205151f8f3c4SKonstantin Khlebnikov cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); 205251f8f3c4SKonstantin Khlebnikov 2053655042ccSVivek Goyal sb->s_magic = OVERLAYFS_SUPER_MAGIC; 20542d2f2d73SMiklos Szeredi sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : 20552d2f2d73SMiklos Szeredi ovl_trusted_xattr_handlers; 2056ad204488SMiklos Szeredi sb->s_fs_info = ofs; 2057de2a4a50SMiklos Szeredi sb->s_flags |= SB_POSIXACL; 205832b1924bSKonstantin Khlebnikov sb->s_iflags |= SB_I_SKIP_SYNC; 2059655042ccSVivek Goyal 2060c6fe6254SMiklos Szeredi err = -ENOMEM; 20612effc5c2SAmir Goldstein root_dentry = ovl_get_root(sb, upperpath.dentry, oe); 2062e9be9d5eSMiklos Szeredi if (!root_dentry) 20634155c10aSMiklos Szeredi goto out_free_oe; 2064e9be9d5eSMiklos Szeredi 2065e9be9d5eSMiklos Szeredi mntput(upperpath.mnt); 2066b8e42a65SMiklos Szeredi kfree(splitlower); 2067ed06e069SMiklos Szeredi 2068e9be9d5eSMiklos Szeredi sb->s_root = root_dentry; 2069e9be9d5eSMiklos Szeredi 2070e9be9d5eSMiklos Szeredi return 0; 2071e9be9d5eSMiklos Szeredi 20724155c10aSMiklos Szeredi out_free_oe: 20734155c10aSMiklos Szeredi ovl_entry_stack_free(oe); 2074b9343632SChandan Rajendra kfree(oe); 20754155c10aSMiklos Szeredi out_err: 2076b8e42a65SMiklos Szeredi kfree(splitlower); 2077e9be9d5eSMiklos Szeredi path_put(&upperpath); 2078ad204488SMiklos Szeredi ovl_free_fs(ofs); 2079e9be9d5eSMiklos Szeredi out: 2080e9be9d5eSMiklos Szeredi return err; 2081e9be9d5eSMiklos Szeredi } 2082e9be9d5eSMiklos Szeredi 2083e9be9d5eSMiklos Szeredi static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, 2084e9be9d5eSMiklos Szeredi const char *dev_name, void *raw_data) 2085e9be9d5eSMiklos Szeredi { 2086e9be9d5eSMiklos Szeredi return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); 2087e9be9d5eSMiklos Szeredi } 2088e9be9d5eSMiklos Szeredi 2089e9be9d5eSMiklos Szeredi static struct file_system_type ovl_fs_type = { 2090e9be9d5eSMiklos Szeredi .owner = THIS_MODULE, 2091ef94b186SMiklos Szeredi .name = "overlay", 2092459c7c56SMiklos Szeredi .fs_flags = FS_USERNS_MOUNT, 2093e9be9d5eSMiklos Szeredi .mount = ovl_mount, 2094e9be9d5eSMiklos Szeredi .kill_sb = kill_anon_super, 2095e9be9d5eSMiklos Szeredi }; 2096ef94b186SMiklos Szeredi MODULE_ALIAS_FS("overlay"); 2097e9be9d5eSMiklos Szeredi 209813cf199dSAmir Goldstein static void ovl_inode_init_once(void *foo) 209913cf199dSAmir Goldstein { 210013cf199dSAmir Goldstein struct ovl_inode *oi = foo; 210113cf199dSAmir Goldstein 210213cf199dSAmir Goldstein inode_init_once(&oi->vfs_inode); 210313cf199dSAmir Goldstein } 210413cf199dSAmir Goldstein 2105e9be9d5eSMiklos Szeredi static int __init ovl_init(void) 2106e9be9d5eSMiklos Szeredi { 210713cf199dSAmir Goldstein int err; 210813cf199dSAmir Goldstein 210913cf199dSAmir Goldstein ovl_inode_cachep = kmem_cache_create("ovl_inode", 211013cf199dSAmir Goldstein sizeof(struct ovl_inode), 0, 211113cf199dSAmir Goldstein (SLAB_RECLAIM_ACCOUNT| 211213cf199dSAmir Goldstein SLAB_MEM_SPREAD|SLAB_ACCOUNT), 211313cf199dSAmir Goldstein ovl_inode_init_once); 211413cf199dSAmir Goldstein if (ovl_inode_cachep == NULL) 211513cf199dSAmir Goldstein return -ENOMEM; 211613cf199dSAmir Goldstein 21172406a307SJiufei Xue err = ovl_aio_request_cache_init(); 21182406a307SJiufei Xue if (!err) { 211913cf199dSAmir Goldstein err = register_filesystem(&ovl_fs_type); 21202406a307SJiufei Xue if (!err) 21212406a307SJiufei Xue return 0; 21222406a307SJiufei Xue 21232406a307SJiufei Xue ovl_aio_request_cache_destroy(); 21242406a307SJiufei Xue } 212513cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 212613cf199dSAmir Goldstein 212713cf199dSAmir Goldstein return err; 2128e9be9d5eSMiklos Szeredi } 2129e9be9d5eSMiklos Szeredi 2130e9be9d5eSMiklos Szeredi static void __exit ovl_exit(void) 2131e9be9d5eSMiklos Szeredi { 2132e9be9d5eSMiklos Szeredi unregister_filesystem(&ovl_fs_type); 213313cf199dSAmir Goldstein 213413cf199dSAmir Goldstein /* 213513cf199dSAmir Goldstein * Make sure all delayed rcu free inodes are flushed before we 213613cf199dSAmir Goldstein * destroy cache. 213713cf199dSAmir Goldstein */ 213813cf199dSAmir Goldstein rcu_barrier(); 213913cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 21402406a307SJiufei Xue ovl_aio_request_cache_destroy(); 2141e9be9d5eSMiklos Szeredi } 2142e9be9d5eSMiklos Szeredi 2143e9be9d5eSMiklos Szeredi module_init(ovl_init); 2144e9be9d5eSMiklos Szeredi module_exit(ovl_exit); 2145