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> 18e9be9d5eSMiklos Szeredi #include "overlayfs.h" 19e9be9d5eSMiklos Szeredi 20e9be9d5eSMiklos Szeredi MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); 21e9be9d5eSMiklos Szeredi MODULE_DESCRIPTION("Overlay filesystem"); 22e9be9d5eSMiklos Szeredi MODULE_LICENSE("GPL"); 23e9be9d5eSMiklos Szeredi 24e9be9d5eSMiklos Szeredi 25e9be9d5eSMiklos Szeredi struct ovl_dir_cache; 26e9be9d5eSMiklos Szeredi 27a78d9f0dSMiklos Szeredi #define OVL_MAX_STACK 500 28a78d9f0dSMiklos Szeredi 29688ea0e5SMiklos Szeredi static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); 30688ea0e5SMiklos Szeredi module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); 31253e7483SNicolas Schier MODULE_PARM_DESC(redirect_dir, 32688ea0e5SMiklos Szeredi "Default to on or off for the redirect_dir feature"); 33e9be9d5eSMiklos Szeredi 34438c84c2SMiklos Szeredi static bool ovl_redirect_always_follow = 35438c84c2SMiklos Szeredi IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW); 36438c84c2SMiklos Szeredi module_param_named(redirect_always_follow, ovl_redirect_always_follow, 37438c84c2SMiklos Szeredi bool, 0644); 38253e7483SNicolas Schier MODULE_PARM_DESC(redirect_always_follow, 39438c84c2SMiklos Szeredi "Follow redirects even if redirect_dir feature is turned off"); 40438c84c2SMiklos Szeredi 4102bcd157SAmir Goldstein static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); 4202bcd157SAmir Goldstein module_param_named(index, ovl_index_def, bool, 0644); 43253e7483SNicolas Schier MODULE_PARM_DESC(index, 4402bcd157SAmir Goldstein "Default to on or off for the inodes index feature"); 4502bcd157SAmir Goldstein 46f168f109SAmir Goldstein static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT); 47f168f109SAmir Goldstein module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644); 48253e7483SNicolas Schier MODULE_PARM_DESC(nfs_export, 49f168f109SAmir Goldstein "Default to on or off for the NFS export feature"); 50f168f109SAmir Goldstein 51795939a9SAmir Goldstein static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO); 52795939a9SAmir Goldstein module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644); 53253e7483SNicolas Schier MODULE_PARM_DESC(xino_auto, 54795939a9SAmir Goldstein "Auto enable xino feature"); 55795939a9SAmir Goldstein 564155c10aSMiklos Szeredi static void ovl_entry_stack_free(struct ovl_entry *oe) 574155c10aSMiklos Szeredi { 584155c10aSMiklos Szeredi unsigned int i; 594155c10aSMiklos Szeredi 604155c10aSMiklos Szeredi for (i = 0; i < oe->numlower; i++) 614155c10aSMiklos Szeredi dput(oe->lowerstack[i].dentry); 624155c10aSMiklos Szeredi } 634155c10aSMiklos Szeredi 64d5791044SVivek Goyal static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY); 65d5791044SVivek Goyal module_param_named(metacopy, ovl_metacopy_def, bool, 0644); 66253e7483SNicolas Schier MODULE_PARM_DESC(metacopy, 67d5791044SVivek Goyal "Default to on or off for the metadata only copy up feature"); 68d5791044SVivek Goyal 69e9be9d5eSMiklos Szeredi static void ovl_dentry_release(struct dentry *dentry) 70e9be9d5eSMiklos Szeredi { 71e9be9d5eSMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 72e9be9d5eSMiklos Szeredi 73e9be9d5eSMiklos Szeredi if (oe) { 744155c10aSMiklos Szeredi ovl_entry_stack_free(oe); 75e9be9d5eSMiklos Szeredi kfree_rcu(oe, rcu); 76e9be9d5eSMiklos Szeredi } 77e9be9d5eSMiklos Szeredi } 78e9be9d5eSMiklos Szeredi 792d902671SMiklos Szeredi static struct dentry *ovl_d_real(struct dentry *dentry, 80fb16043bSMiklos Szeredi const struct inode *inode) 81d101a125SMiklos Szeredi { 82d101a125SMiklos Szeredi struct dentry *real; 83d101a125SMiklos Szeredi 84e8c985baSMiklos Szeredi /* It's an overlay file */ 85e8c985baSMiklos Szeredi if (inode && d_inode(dentry) == inode) 86e8c985baSMiklos Szeredi return dentry; 87e8c985baSMiklos Szeredi 88ca4c8a3aSMiklos Szeredi if (!d_is_reg(dentry)) { 89d101a125SMiklos Szeredi if (!inode || inode == d_inode(dentry)) 90d101a125SMiklos Szeredi return dentry; 91d101a125SMiklos Szeredi goto bug; 92d101a125SMiklos Szeredi } 93d101a125SMiklos Szeredi 94d101a125SMiklos Szeredi real = ovl_dentry_upper(dentry); 952c3d7358SVivek Goyal if (real && (inode == d_inode(real))) 96d101a125SMiklos Szeredi return real; 97d101a125SMiklos Szeredi 982c3d7358SVivek Goyal if (real && !inode && ovl_has_upperdata(d_inode(dentry))) 992c3d7358SVivek Goyal return real; 1002c3d7358SVivek Goyal 1012c3d7358SVivek Goyal real = ovl_dentry_lowerdata(dentry); 102d101a125SMiklos Szeredi if (!real) 103d101a125SMiklos Szeredi goto bug; 104d101a125SMiklos Szeredi 105c4fcfc16SMiklos Szeredi /* Handle recursion */ 106fb16043bSMiklos Szeredi real = d_real(real, inode); 107c4fcfc16SMiklos Szeredi 108d101a125SMiklos Szeredi if (!inode || inode == d_inode(real)) 109d101a125SMiklos Szeredi return real; 110d101a125SMiklos Szeredi bug: 111656189d2SMiklos Szeredi WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, 112d101a125SMiklos Szeredi inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); 113d101a125SMiklos Szeredi return dentry; 114d101a125SMiklos Szeredi } 115d101a125SMiklos Szeredi 1163bb7df92SMiklos Szeredi static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) 1173bb7df92SMiklos Szeredi { 1183bb7df92SMiklos Szeredi int ret = 1; 1193bb7df92SMiklos Szeredi 1203bb7df92SMiklos Szeredi if (weak) { 1213bb7df92SMiklos Szeredi if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) 1223bb7df92SMiklos Szeredi ret = d->d_op->d_weak_revalidate(d, flags); 1233bb7df92SMiklos Szeredi } else if (d->d_flags & DCACHE_OP_REVALIDATE) { 1243bb7df92SMiklos Szeredi ret = d->d_op->d_revalidate(d, flags); 1253bb7df92SMiklos Szeredi if (!ret) { 1263bb7df92SMiklos Szeredi if (!(flags & LOOKUP_RCU)) 1273bb7df92SMiklos Szeredi d_invalidate(d); 1283bb7df92SMiklos Szeredi ret = -ESTALE; 1293bb7df92SMiklos Szeredi } 1303bb7df92SMiklos Szeredi } 1313bb7df92SMiklos Szeredi return ret; 1323bb7df92SMiklos Szeredi } 1333bb7df92SMiklos Szeredi 1343bb7df92SMiklos Szeredi static int ovl_dentry_revalidate_common(struct dentry *dentry, 1353bb7df92SMiklos Szeredi unsigned int flags, bool weak) 1367c03b5d4SMiklos Szeredi { 1377c03b5d4SMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 138bccece1eSMiklos Szeredi struct dentry *upper; 1397c03b5d4SMiklos Szeredi unsigned int i; 1407c03b5d4SMiklos Szeredi int ret = 1; 1417c03b5d4SMiklos Szeredi 142bccece1eSMiklos Szeredi upper = ovl_dentry_upper(dentry); 143bccece1eSMiklos Szeredi if (upper) 144bccece1eSMiklos Szeredi ret = ovl_revalidate_real(upper, flags, weak); 145bccece1eSMiklos Szeredi 1463bb7df92SMiklos Szeredi for (i = 0; ret > 0 && i < oe->numlower; i++) { 1473bb7df92SMiklos Szeredi ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, 1483bb7df92SMiklos Szeredi weak); 1493bb7df92SMiklos Szeredi } 1507c03b5d4SMiklos Szeredi return ret; 1517c03b5d4SMiklos Szeredi } 1523bb7df92SMiklos Szeredi 1533bb7df92SMiklos Szeredi static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) 1543bb7df92SMiklos Szeredi { 1553bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, false); 1567c03b5d4SMiklos Szeredi } 1577c03b5d4SMiklos Szeredi 1587c03b5d4SMiklos Szeredi static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) 1597c03b5d4SMiklos Szeredi { 1603bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, true); 1617c03b5d4SMiklos Szeredi } 1627c03b5d4SMiklos Szeredi 163e9be9d5eSMiklos Szeredi static const struct dentry_operations ovl_dentry_operations = { 164e9be9d5eSMiklos Szeredi .d_release = ovl_dentry_release, 165d101a125SMiklos Szeredi .d_real = ovl_d_real, 1667c03b5d4SMiklos Szeredi .d_revalidate = ovl_dentry_revalidate, 1677c03b5d4SMiklos Szeredi .d_weak_revalidate = ovl_dentry_weak_revalidate, 1687c03b5d4SMiklos Szeredi }; 1697c03b5d4SMiklos Szeredi 17013cf199dSAmir Goldstein static struct kmem_cache *ovl_inode_cachep; 17113cf199dSAmir Goldstein 17213cf199dSAmir Goldstein static struct inode *ovl_alloc_inode(struct super_block *sb) 17313cf199dSAmir Goldstein { 17413cf199dSAmir Goldstein struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); 17513cf199dSAmir Goldstein 176b3885bd6SHirofumi Nakagawa if (!oi) 177b3885bd6SHirofumi Nakagawa return NULL; 178b3885bd6SHirofumi Nakagawa 17904a01ac7SMiklos Szeredi oi->cache = NULL; 180cf31c463SMiklos Szeredi oi->redirect = NULL; 18104a01ac7SMiklos Szeredi oi->version = 0; 18213c72075SMiklos Szeredi oi->flags = 0; 18309d8b586SMiklos Szeredi oi->__upperdentry = NULL; 18425b7713aSMiklos Szeredi oi->lower = NULL; 1852664bd08SVivek Goyal oi->lowerdata = NULL; 186a015dafcSAmir Goldstein mutex_init(&oi->lock); 18725b7713aSMiklos Szeredi 18813cf199dSAmir Goldstein return &oi->vfs_inode; 18913cf199dSAmir Goldstein } 19013cf199dSAmir Goldstein 1910b269dedSAl Viro static void ovl_free_inode(struct inode *inode) 19213cf199dSAmir Goldstein { 1930b269dedSAl Viro struct ovl_inode *oi = OVL_I(inode); 19413cf199dSAmir Goldstein 1950b269dedSAl Viro kfree(oi->redirect); 1960b269dedSAl Viro mutex_destroy(&oi->lock); 1970b269dedSAl Viro kmem_cache_free(ovl_inode_cachep, oi); 19813cf199dSAmir Goldstein } 19913cf199dSAmir Goldstein 20013cf199dSAmir Goldstein static void ovl_destroy_inode(struct inode *inode) 20113cf199dSAmir Goldstein { 20209d8b586SMiklos Szeredi struct ovl_inode *oi = OVL_I(inode); 20309d8b586SMiklos Szeredi 20409d8b586SMiklos Szeredi dput(oi->__upperdentry); 20531747edaSAmir Goldstein iput(oi->lower); 2062664bd08SVivek Goyal if (S_ISDIR(inode->i_mode)) 2074edb83bbSMiklos Szeredi ovl_dir_cache_free(inode); 2082664bd08SVivek Goyal else 2092664bd08SVivek Goyal iput(oi->lowerdata); 21013cf199dSAmir Goldstein } 21113cf199dSAmir Goldstein 212ad204488SMiklos Szeredi static void ovl_free_fs(struct ovl_fs *ofs) 213e9be9d5eSMiklos Szeredi { 214df820f8dSMiklos Szeredi struct vfsmount **mounts; 215dd662667SMiklos Szeredi unsigned i; 216e9be9d5eSMiklos Szeredi 2170be0bfd2SAmir Goldstein iput(ofs->workbasedir_trap); 218146d62e5SAmir Goldstein iput(ofs->indexdir_trap); 219146d62e5SAmir Goldstein iput(ofs->workdir_trap); 220c21c839bSChengguang Xu dput(ofs->whiteout); 221ad204488SMiklos Szeredi dput(ofs->indexdir); 222ad204488SMiklos Szeredi dput(ofs->workdir); 223ad204488SMiklos Szeredi if (ofs->workdir_locked) 224ad204488SMiklos Szeredi ovl_inuse_unlock(ofs->workbasedir); 225ad204488SMiklos Szeredi dput(ofs->workbasedir); 226ad204488SMiklos Szeredi if (ofs->upperdir_locked) 22708f4c7c8SMiklos Szeredi ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); 228df820f8dSMiklos Szeredi 229df820f8dSMiklos Szeredi /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ 230df820f8dSMiklos Szeredi mounts = (struct vfsmount **) ofs->layers; 231b8e42a65SMiklos Szeredi for (i = 0; i < ofs->numlayer; i++) { 23294375f9dSAmir Goldstein iput(ofs->layers[i].trap); 233df820f8dSMiklos Szeredi mounts[i] = ofs->layers[i].mnt; 234146d62e5SAmir Goldstein } 235df820f8dSMiklos Szeredi kern_unmount_array(mounts, ofs->numlayer); 23694375f9dSAmir Goldstein kfree(ofs->layers); 237b7bf9908SAmir Goldstein for (i = 0; i < ofs->numfs; i++) 23807f1e596SAmir Goldstein free_anon_bdev(ofs->fs[i].pseudo_dev); 23907f1e596SAmir Goldstein kfree(ofs->fs); 240e9be9d5eSMiklos Szeredi 241ad204488SMiklos Szeredi kfree(ofs->config.lowerdir); 242ad204488SMiklos Szeredi kfree(ofs->config.upperdir); 243ad204488SMiklos Szeredi kfree(ofs->config.workdir); 244438c84c2SMiklos Szeredi kfree(ofs->config.redirect_mode); 245ad204488SMiklos Szeredi if (ofs->creator_cred) 246ad204488SMiklos Szeredi put_cred(ofs->creator_cred); 247ad204488SMiklos Szeredi kfree(ofs); 248e9be9d5eSMiklos Szeredi } 249e9be9d5eSMiklos Szeredi 250a9075cdbSMiklos Szeredi static void ovl_put_super(struct super_block *sb) 251a9075cdbSMiklos Szeredi { 252a9075cdbSMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 253a9075cdbSMiklos Szeredi 254a9075cdbSMiklos Szeredi ovl_free_fs(ofs); 255a9075cdbSMiklos Szeredi } 256a9075cdbSMiklos Szeredi 257e8d4bfe3SChengguang Xu /* Sync real dirty inodes in upper filesystem (if it exists) */ 258e593b2bfSAmir Goldstein static int ovl_sync_fs(struct super_block *sb, int wait) 259e593b2bfSAmir Goldstein { 260ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 261e593b2bfSAmir Goldstein struct super_block *upper_sb; 262e593b2bfSAmir Goldstein int ret; 263e593b2bfSAmir Goldstein 26408f4c7c8SMiklos Szeredi if (!ovl_upper_mnt(ofs)) 265e593b2bfSAmir Goldstein return 0; 266e8d4bfe3SChengguang Xu 267c86243b0SVivek Goyal if (!ovl_should_sync(ofs)) 268c86243b0SVivek Goyal return 0; 269e8d4bfe3SChengguang Xu /* 27032b1924bSKonstantin Khlebnikov * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). 27132b1924bSKonstantin Khlebnikov * All the super blocks will be iterated, including upper_sb. 272e8d4bfe3SChengguang Xu * 273e8d4bfe3SChengguang Xu * If this is a syncfs(2) call, then we do need to call 274e8d4bfe3SChengguang Xu * sync_filesystem() on upper_sb, but enough if we do it when being 275e8d4bfe3SChengguang Xu * called with wait == 1. 276e8d4bfe3SChengguang Xu */ 277e8d4bfe3SChengguang Xu if (!wait) 278e593b2bfSAmir Goldstein return 0; 279e593b2bfSAmir Goldstein 28008f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 281e8d4bfe3SChengguang Xu 282e593b2bfSAmir Goldstein down_read(&upper_sb->s_umount); 283e8d4bfe3SChengguang Xu ret = sync_filesystem(upper_sb); 284e593b2bfSAmir Goldstein up_read(&upper_sb->s_umount); 285e8d4bfe3SChengguang Xu 286e593b2bfSAmir Goldstein return ret; 287e593b2bfSAmir Goldstein } 288e593b2bfSAmir Goldstein 289cc259639SAndy Whitcroft /** 290cc259639SAndy Whitcroft * ovl_statfs 291cc259639SAndy Whitcroft * @sb: The overlayfs super block 292cc259639SAndy Whitcroft * @buf: The struct kstatfs to fill in with stats 293cc259639SAndy Whitcroft * 294cc259639SAndy Whitcroft * Get the filesystem statistics. As writes always target the upper layer 2954ebc5818SMiklos Szeredi * filesystem pass the statfs to the upper filesystem (if it exists) 296cc259639SAndy Whitcroft */ 297cc259639SAndy Whitcroft static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) 298cc259639SAndy Whitcroft { 299cc259639SAndy Whitcroft struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 300cc259639SAndy Whitcroft struct dentry *root_dentry = dentry->d_sb->s_root; 301cc259639SAndy Whitcroft struct path path; 302cc259639SAndy Whitcroft int err; 303cc259639SAndy Whitcroft 3044ebc5818SMiklos Szeredi ovl_path_real(root_dentry, &path); 305cc259639SAndy Whitcroft 306cc259639SAndy Whitcroft err = vfs_statfs(&path, buf); 307cc259639SAndy Whitcroft if (!err) { 3086b2d5fe4SMiklos Szeredi buf->f_namelen = ofs->namelen; 309cc259639SAndy Whitcroft buf->f_type = OVERLAYFS_SUPER_MAGIC; 310cc259639SAndy Whitcroft } 311cc259639SAndy Whitcroft 312cc259639SAndy Whitcroft return err; 313cc259639SAndy Whitcroft } 314cc259639SAndy Whitcroft 31502bcd157SAmir Goldstein /* Will this overlay be forced to mount/remount ro? */ 316ad204488SMiklos Szeredi static bool ovl_force_readonly(struct ovl_fs *ofs) 31702bcd157SAmir Goldstein { 31808f4c7c8SMiklos Szeredi return (!ovl_upper_mnt(ofs) || !ofs->workdir); 31902bcd157SAmir Goldstein } 32002bcd157SAmir Goldstein 321438c84c2SMiklos Szeredi static const char *ovl_redirect_mode_def(void) 322438c84c2SMiklos Szeredi { 323438c84c2SMiklos Szeredi return ovl_redirect_dir_def ? "on" : "off"; 324438c84c2SMiklos Szeredi } 325438c84c2SMiklos Szeredi 326795939a9SAmir Goldstein static const char * const ovl_xino_str[] = { 327795939a9SAmir Goldstein "off", 328795939a9SAmir Goldstein "auto", 329795939a9SAmir Goldstein "on", 330795939a9SAmir Goldstein }; 331795939a9SAmir Goldstein 332795939a9SAmir Goldstein static inline int ovl_xino_def(void) 333795939a9SAmir Goldstein { 334795939a9SAmir Goldstein return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; 335795939a9SAmir Goldstein } 336795939a9SAmir Goldstein 337f45827e8SErez Zadok /** 338f45827e8SErez Zadok * ovl_show_options 339f45827e8SErez Zadok * 340f45827e8SErez Zadok * Prints the mount options for a given superblock. 341f45827e8SErez Zadok * Returns zero; does not fail. 342f45827e8SErez Zadok */ 343f45827e8SErez Zadok static int ovl_show_options(struct seq_file *m, struct dentry *dentry) 344f45827e8SErez Zadok { 345f45827e8SErez Zadok struct super_block *sb = dentry->d_sb; 346ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 347f45827e8SErez Zadok 348ad204488SMiklos Szeredi seq_show_option(m, "lowerdir", ofs->config.lowerdir); 349ad204488SMiklos Szeredi if (ofs->config.upperdir) { 350ad204488SMiklos Szeredi seq_show_option(m, "upperdir", ofs->config.upperdir); 351ad204488SMiklos Szeredi seq_show_option(m, "workdir", ofs->config.workdir); 35253a08cb9SMiklos Szeredi } 353ad204488SMiklos Szeredi if (ofs->config.default_permissions) 3548d3095f4SMiklos Szeredi seq_puts(m, ",default_permissions"); 355438c84c2SMiklos Szeredi if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) 356438c84c2SMiklos Szeredi seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); 357ad204488SMiklos Szeredi if (ofs->config.index != ovl_index_def) 358438c84c2SMiklos Szeredi seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); 359*5830fb6bSPavel Tikhomirov if (!ofs->config.uuid) 360*5830fb6bSPavel Tikhomirov seq_puts(m, ",uuid=off"); 361f168f109SAmir Goldstein if (ofs->config.nfs_export != ovl_nfs_export_def) 362f168f109SAmir Goldstein seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? 363f168f109SAmir Goldstein "on" : "off"); 3640f831ec8SAmir Goldstein if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) 365795939a9SAmir Goldstein seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); 366d5791044SVivek Goyal if (ofs->config.metacopy != ovl_metacopy_def) 367d5791044SVivek Goyal seq_printf(m, ",metacopy=%s", 368d5791044SVivek Goyal ofs->config.metacopy ? "on" : "off"); 369c86243b0SVivek Goyal if (ofs->config.ovl_volatile) 370c86243b0SVivek Goyal seq_puts(m, ",volatile"); 371f45827e8SErez Zadok return 0; 372f45827e8SErez Zadok } 373f45827e8SErez Zadok 3743cdf6fe9SSeunghun Lee static int ovl_remount(struct super_block *sb, int *flags, char *data) 3753cdf6fe9SSeunghun Lee { 376ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 377399c109dSChengguang Xu struct super_block *upper_sb; 378399c109dSChengguang Xu int ret = 0; 3793cdf6fe9SSeunghun Lee 3801751e8a6SLinus Torvalds if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) 3813cdf6fe9SSeunghun Lee return -EROFS; 3823cdf6fe9SSeunghun Lee 383399c109dSChengguang Xu if (*flags & SB_RDONLY && !sb_rdonly(sb)) { 38408f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 385c86243b0SVivek Goyal if (ovl_should_sync(ofs)) { 386399c109dSChengguang Xu down_read(&upper_sb->s_umount); 387399c109dSChengguang Xu ret = sync_filesystem(upper_sb); 388399c109dSChengguang Xu up_read(&upper_sb->s_umount); 389399c109dSChengguang Xu } 390c86243b0SVivek Goyal } 391399c109dSChengguang Xu 392399c109dSChengguang Xu return ret; 3933cdf6fe9SSeunghun Lee } 3943cdf6fe9SSeunghun Lee 395e9be9d5eSMiklos Szeredi static const struct super_operations ovl_super_operations = { 39613cf199dSAmir Goldstein .alloc_inode = ovl_alloc_inode, 3970b269dedSAl Viro .free_inode = ovl_free_inode, 39813cf199dSAmir Goldstein .destroy_inode = ovl_destroy_inode, 39913cf199dSAmir Goldstein .drop_inode = generic_delete_inode, 400e9be9d5eSMiklos Szeredi .put_super = ovl_put_super, 401e593b2bfSAmir Goldstein .sync_fs = ovl_sync_fs, 402cc259639SAndy Whitcroft .statfs = ovl_statfs, 403f45827e8SErez Zadok .show_options = ovl_show_options, 4043cdf6fe9SSeunghun Lee .remount_fs = ovl_remount, 405e9be9d5eSMiklos Szeredi }; 406e9be9d5eSMiklos Szeredi 407e9be9d5eSMiklos Szeredi enum { 408e9be9d5eSMiklos Szeredi OPT_LOWERDIR, 409e9be9d5eSMiklos Szeredi OPT_UPPERDIR, 410e9be9d5eSMiklos Szeredi OPT_WORKDIR, 4118d3095f4SMiklos Szeredi OPT_DEFAULT_PERMISSIONS, 412438c84c2SMiklos Szeredi OPT_REDIRECT_DIR, 41302bcd157SAmir Goldstein OPT_INDEX_ON, 41402bcd157SAmir Goldstein OPT_INDEX_OFF, 415*5830fb6bSPavel Tikhomirov OPT_UUID_ON, 416*5830fb6bSPavel Tikhomirov OPT_UUID_OFF, 417f168f109SAmir Goldstein OPT_NFS_EXPORT_ON, 418f168f109SAmir Goldstein OPT_NFS_EXPORT_OFF, 419795939a9SAmir Goldstein OPT_XINO_ON, 420795939a9SAmir Goldstein OPT_XINO_OFF, 421795939a9SAmir Goldstein OPT_XINO_AUTO, 422d5791044SVivek Goyal OPT_METACOPY_ON, 423d5791044SVivek Goyal OPT_METACOPY_OFF, 424c86243b0SVivek Goyal OPT_VOLATILE, 425e9be9d5eSMiklos Szeredi OPT_ERR, 426e9be9d5eSMiklos Szeredi }; 427e9be9d5eSMiklos Szeredi 428e9be9d5eSMiklos Szeredi static const match_table_t ovl_tokens = { 429e9be9d5eSMiklos Szeredi {OPT_LOWERDIR, "lowerdir=%s"}, 430e9be9d5eSMiklos Szeredi {OPT_UPPERDIR, "upperdir=%s"}, 431e9be9d5eSMiklos Szeredi {OPT_WORKDIR, "workdir=%s"}, 4328d3095f4SMiklos Szeredi {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 433438c84c2SMiklos Szeredi {OPT_REDIRECT_DIR, "redirect_dir=%s"}, 43402bcd157SAmir Goldstein {OPT_INDEX_ON, "index=on"}, 43502bcd157SAmir Goldstein {OPT_INDEX_OFF, "index=off"}, 436*5830fb6bSPavel Tikhomirov {OPT_UUID_ON, "uuid=on"}, 437*5830fb6bSPavel Tikhomirov {OPT_UUID_OFF, "uuid=off"}, 438f168f109SAmir Goldstein {OPT_NFS_EXPORT_ON, "nfs_export=on"}, 439f168f109SAmir Goldstein {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, 440795939a9SAmir Goldstein {OPT_XINO_ON, "xino=on"}, 441795939a9SAmir Goldstein {OPT_XINO_OFF, "xino=off"}, 442795939a9SAmir Goldstein {OPT_XINO_AUTO, "xino=auto"}, 443d5791044SVivek Goyal {OPT_METACOPY_ON, "metacopy=on"}, 444d5791044SVivek Goyal {OPT_METACOPY_OFF, "metacopy=off"}, 445c86243b0SVivek Goyal {OPT_VOLATILE, "volatile"}, 446e9be9d5eSMiklos Szeredi {OPT_ERR, NULL} 447e9be9d5eSMiklos Szeredi }; 448e9be9d5eSMiklos Szeredi 44991c77947SMiklos Szeredi static char *ovl_next_opt(char **s) 45091c77947SMiklos Szeredi { 45191c77947SMiklos Szeredi char *sbegin = *s; 45291c77947SMiklos Szeredi char *p; 45391c77947SMiklos Szeredi 45491c77947SMiklos Szeredi if (sbegin == NULL) 45591c77947SMiklos Szeredi return NULL; 45691c77947SMiklos Szeredi 45791c77947SMiklos Szeredi for (p = sbegin; *p; p++) { 45891c77947SMiklos Szeredi if (*p == '\\') { 45991c77947SMiklos Szeredi p++; 46091c77947SMiklos Szeredi if (!*p) 46191c77947SMiklos Szeredi break; 46291c77947SMiklos Szeredi } else if (*p == ',') { 46391c77947SMiklos Szeredi *p = '\0'; 46491c77947SMiklos Szeredi *s = p + 1; 46591c77947SMiklos Szeredi return sbegin; 46691c77947SMiklos Szeredi } 46791c77947SMiklos Szeredi } 46891c77947SMiklos Szeredi *s = NULL; 46991c77947SMiklos Szeredi return sbegin; 47091c77947SMiklos Szeredi } 47191c77947SMiklos Szeredi 472438c84c2SMiklos Szeredi static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) 473438c84c2SMiklos Szeredi { 474438c84c2SMiklos Szeredi if (strcmp(mode, "on") == 0) { 475438c84c2SMiklos Szeredi config->redirect_dir = true; 476438c84c2SMiklos Szeredi /* 477438c84c2SMiklos Szeredi * Does not make sense to have redirect creation without 478438c84c2SMiklos Szeredi * redirect following. 479438c84c2SMiklos Szeredi */ 480438c84c2SMiklos Szeredi config->redirect_follow = true; 481438c84c2SMiklos Szeredi } else if (strcmp(mode, "follow") == 0) { 482438c84c2SMiklos Szeredi config->redirect_follow = true; 483438c84c2SMiklos Szeredi } else if (strcmp(mode, "off") == 0) { 484438c84c2SMiklos Szeredi if (ovl_redirect_always_follow) 485438c84c2SMiklos Szeredi config->redirect_follow = true; 486438c84c2SMiklos Szeredi } else if (strcmp(mode, "nofollow") != 0) { 4871bd0a3aeSlijiazi pr_err("bad mount option \"redirect_dir=%s\"\n", 488438c84c2SMiklos Szeredi mode); 489438c84c2SMiklos Szeredi return -EINVAL; 490438c84c2SMiklos Szeredi } 491438c84c2SMiklos Szeredi 492438c84c2SMiklos Szeredi return 0; 493438c84c2SMiklos Szeredi } 494438c84c2SMiklos Szeredi 495e9be9d5eSMiklos Szeredi static int ovl_parse_opt(char *opt, struct ovl_config *config) 496e9be9d5eSMiklos Szeredi { 497e9be9d5eSMiklos Szeredi char *p; 498d5791044SVivek Goyal int err; 499d47748e5SMiklos Szeredi bool metacopy_opt = false, redirect_opt = false; 500b0def88dSAmir Goldstein bool nfs_export_opt = false, index_opt = false; 501e9be9d5eSMiklos Szeredi 502438c84c2SMiklos Szeredi config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); 503438c84c2SMiklos Szeredi if (!config->redirect_mode) 504438c84c2SMiklos Szeredi return -ENOMEM; 505438c84c2SMiklos Szeredi 50691c77947SMiklos Szeredi while ((p = ovl_next_opt(&opt)) != NULL) { 507e9be9d5eSMiklos Szeredi int token; 508e9be9d5eSMiklos Szeredi substring_t args[MAX_OPT_ARGS]; 509e9be9d5eSMiklos Szeredi 510e9be9d5eSMiklos Szeredi if (!*p) 511e9be9d5eSMiklos Szeredi continue; 512e9be9d5eSMiklos Szeredi 513e9be9d5eSMiklos Szeredi token = match_token(p, ovl_tokens, args); 514e9be9d5eSMiklos Szeredi switch (token) { 515e9be9d5eSMiklos Szeredi case OPT_UPPERDIR: 516e9be9d5eSMiklos Szeredi kfree(config->upperdir); 517e9be9d5eSMiklos Szeredi config->upperdir = match_strdup(&args[0]); 518e9be9d5eSMiklos Szeredi if (!config->upperdir) 519e9be9d5eSMiklos Szeredi return -ENOMEM; 520e9be9d5eSMiklos Szeredi break; 521e9be9d5eSMiklos Szeredi 522e9be9d5eSMiklos Szeredi case OPT_LOWERDIR: 523e9be9d5eSMiklos Szeredi kfree(config->lowerdir); 524e9be9d5eSMiklos Szeredi config->lowerdir = match_strdup(&args[0]); 525e9be9d5eSMiklos Szeredi if (!config->lowerdir) 526e9be9d5eSMiklos Szeredi return -ENOMEM; 527e9be9d5eSMiklos Szeredi break; 528e9be9d5eSMiklos Szeredi 529e9be9d5eSMiklos Szeredi case OPT_WORKDIR: 530e9be9d5eSMiklos Szeredi kfree(config->workdir); 531e9be9d5eSMiklos Szeredi config->workdir = match_strdup(&args[0]); 532e9be9d5eSMiklos Szeredi if (!config->workdir) 533e9be9d5eSMiklos Szeredi return -ENOMEM; 534e9be9d5eSMiklos Szeredi break; 535e9be9d5eSMiklos Szeredi 5368d3095f4SMiklos Szeredi case OPT_DEFAULT_PERMISSIONS: 5378d3095f4SMiklos Szeredi config->default_permissions = true; 5388d3095f4SMiklos Szeredi break; 5398d3095f4SMiklos Szeredi 540438c84c2SMiklos Szeredi case OPT_REDIRECT_DIR: 541438c84c2SMiklos Szeredi kfree(config->redirect_mode); 542438c84c2SMiklos Szeredi config->redirect_mode = match_strdup(&args[0]); 543438c84c2SMiklos Szeredi if (!config->redirect_mode) 544438c84c2SMiklos Szeredi return -ENOMEM; 545d47748e5SMiklos Szeredi redirect_opt = true; 546a6c60655SMiklos Szeredi break; 547a6c60655SMiklos Szeredi 54802bcd157SAmir Goldstein case OPT_INDEX_ON: 54902bcd157SAmir Goldstein config->index = true; 550b0def88dSAmir Goldstein index_opt = true; 55102bcd157SAmir Goldstein break; 55202bcd157SAmir Goldstein 55302bcd157SAmir Goldstein case OPT_INDEX_OFF: 55402bcd157SAmir Goldstein config->index = false; 555b0def88dSAmir Goldstein index_opt = true; 55602bcd157SAmir Goldstein break; 55702bcd157SAmir Goldstein 558*5830fb6bSPavel Tikhomirov case OPT_UUID_ON: 559*5830fb6bSPavel Tikhomirov config->uuid = true; 560*5830fb6bSPavel Tikhomirov break; 561*5830fb6bSPavel Tikhomirov 562*5830fb6bSPavel Tikhomirov case OPT_UUID_OFF: 563*5830fb6bSPavel Tikhomirov config->uuid = false; 564*5830fb6bSPavel Tikhomirov break; 565*5830fb6bSPavel Tikhomirov 566f168f109SAmir Goldstein case OPT_NFS_EXPORT_ON: 567f168f109SAmir Goldstein config->nfs_export = true; 568b0def88dSAmir Goldstein nfs_export_opt = true; 569f168f109SAmir Goldstein break; 570f168f109SAmir Goldstein 571f168f109SAmir Goldstein case OPT_NFS_EXPORT_OFF: 572f168f109SAmir Goldstein config->nfs_export = false; 573b0def88dSAmir Goldstein nfs_export_opt = true; 574f168f109SAmir Goldstein break; 575f168f109SAmir Goldstein 576795939a9SAmir Goldstein case OPT_XINO_ON: 577795939a9SAmir Goldstein config->xino = OVL_XINO_ON; 578795939a9SAmir Goldstein break; 579795939a9SAmir Goldstein 580795939a9SAmir Goldstein case OPT_XINO_OFF: 581795939a9SAmir Goldstein config->xino = OVL_XINO_OFF; 582795939a9SAmir Goldstein break; 583795939a9SAmir Goldstein 584795939a9SAmir Goldstein case OPT_XINO_AUTO: 585795939a9SAmir Goldstein config->xino = OVL_XINO_AUTO; 586795939a9SAmir Goldstein break; 587795939a9SAmir Goldstein 588d5791044SVivek Goyal case OPT_METACOPY_ON: 589d5791044SVivek Goyal config->metacopy = true; 590d47748e5SMiklos Szeredi metacopy_opt = true; 591d5791044SVivek Goyal break; 592d5791044SVivek Goyal 593d5791044SVivek Goyal case OPT_METACOPY_OFF: 594d5791044SVivek Goyal config->metacopy = false; 595b0def88dSAmir Goldstein metacopy_opt = true; 596d5791044SVivek Goyal break; 597d5791044SVivek Goyal 598c86243b0SVivek Goyal case OPT_VOLATILE: 599c86243b0SVivek Goyal config->ovl_volatile = true; 600c86243b0SVivek Goyal break; 601c86243b0SVivek Goyal 602e9be9d5eSMiklos Szeredi default: 6031bd0a3aeSlijiazi pr_err("unrecognized mount option \"%s\" or missing value\n", 6041bd0a3aeSlijiazi p); 605e9be9d5eSMiklos Szeredi return -EINVAL; 606e9be9d5eSMiklos Szeredi } 607e9be9d5eSMiklos Szeredi } 60871cbad7eShujianyang 609f0e1266eSAmir Goldstein /* Workdir/index are useless in non-upper mount */ 610f0e1266eSAmir Goldstein if (!config->upperdir) { 611f0e1266eSAmir Goldstein if (config->workdir) { 6121bd0a3aeSlijiazi pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", 61371cbad7eShujianyang config->workdir); 61471cbad7eShujianyang kfree(config->workdir); 61571cbad7eShujianyang config->workdir = NULL; 61671cbad7eShujianyang } 617f0e1266eSAmir Goldstein if (config->index && index_opt) { 618f0e1266eSAmir Goldstein pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); 619f0e1266eSAmir Goldstein index_opt = false; 620f0e1266eSAmir Goldstein } 621f0e1266eSAmir Goldstein config->index = false; 622f0e1266eSAmir Goldstein } 62371cbad7eShujianyang 624c86243b0SVivek Goyal if (!config->upperdir && config->ovl_volatile) { 625c86243b0SVivek Goyal pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); 626c86243b0SVivek Goyal config->ovl_volatile = false; 627c86243b0SVivek Goyal } 628c86243b0SVivek Goyal 629d5791044SVivek Goyal err = ovl_parse_redirect_mode(config, config->redirect_mode); 630d5791044SVivek Goyal if (err) 631d5791044SVivek Goyal return err; 632d5791044SVivek Goyal 633d47748e5SMiklos Szeredi /* 634d47748e5SMiklos Szeredi * This is to make the logic below simpler. It doesn't make any other 635d47748e5SMiklos Szeredi * difference, since config->redirect_dir is only used for upper. 636d47748e5SMiklos Szeredi */ 637d47748e5SMiklos Szeredi if (!config->upperdir && config->redirect_follow) 638d47748e5SMiklos Szeredi config->redirect_dir = true; 639d47748e5SMiklos Szeredi 640d47748e5SMiklos Szeredi /* Resolve metacopy -> redirect_dir dependency */ 641d47748e5SMiklos Szeredi if (config->metacopy && !config->redirect_dir) { 642d47748e5SMiklos Szeredi if (metacopy_opt && redirect_opt) { 6431bd0a3aeSlijiazi pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", 644d47748e5SMiklos Szeredi config->redirect_mode); 645d47748e5SMiklos Szeredi return -EINVAL; 646d47748e5SMiklos Szeredi } 647d47748e5SMiklos Szeredi if (redirect_opt) { 648d47748e5SMiklos Szeredi /* 649d47748e5SMiklos Szeredi * There was an explicit redirect_dir=... that resulted 650d47748e5SMiklos Szeredi * in this conflict. 651d47748e5SMiklos Szeredi */ 6521bd0a3aeSlijiazi pr_info("disabling metacopy due to redirect_dir=%s\n", 653d47748e5SMiklos Szeredi config->redirect_mode); 654d5791044SVivek Goyal config->metacopy = false; 655d47748e5SMiklos Szeredi } else { 656d47748e5SMiklos Szeredi /* Automatically enable redirect otherwise. */ 657d47748e5SMiklos Szeredi config->redirect_follow = config->redirect_dir = true; 658d47748e5SMiklos Szeredi } 659d5791044SVivek Goyal } 660d5791044SVivek Goyal 661b0def88dSAmir Goldstein /* Resolve nfs_export -> index dependency */ 662b0def88dSAmir Goldstein if (config->nfs_export && !config->index) { 663f0e1266eSAmir Goldstein if (!config->upperdir && config->redirect_follow) { 664f0e1266eSAmir Goldstein pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); 665f0e1266eSAmir Goldstein config->nfs_export = false; 666f0e1266eSAmir Goldstein } else if (nfs_export_opt && index_opt) { 667b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,index=off\n"); 668b0def88dSAmir Goldstein return -EINVAL; 669f0e1266eSAmir Goldstein } else if (index_opt) { 670b0def88dSAmir Goldstein /* 671b0def88dSAmir Goldstein * There was an explicit index=off that resulted 672b0def88dSAmir Goldstein * in this conflict. 673b0def88dSAmir Goldstein */ 674b0def88dSAmir Goldstein pr_info("disabling nfs_export due to index=off\n"); 675b0def88dSAmir Goldstein config->nfs_export = false; 676b0def88dSAmir Goldstein } else { 677b0def88dSAmir Goldstein /* Automatically enable index otherwise. */ 678b0def88dSAmir Goldstein config->index = true; 679b0def88dSAmir Goldstein } 680b0def88dSAmir Goldstein } 681b0def88dSAmir Goldstein 682b0def88dSAmir Goldstein /* Resolve nfs_export -> !metacopy dependency */ 683b0def88dSAmir Goldstein if (config->nfs_export && config->metacopy) { 684b0def88dSAmir Goldstein if (nfs_export_opt && metacopy_opt) { 685b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,metacopy=on\n"); 686b0def88dSAmir Goldstein return -EINVAL; 687b0def88dSAmir Goldstein } 688b0def88dSAmir Goldstein if (metacopy_opt) { 689b0def88dSAmir Goldstein /* 690b0def88dSAmir Goldstein * There was an explicit metacopy=on that resulted 691b0def88dSAmir Goldstein * in this conflict. 692b0def88dSAmir Goldstein */ 693b0def88dSAmir Goldstein pr_info("disabling nfs_export due to metacopy=on\n"); 694b0def88dSAmir Goldstein config->nfs_export = false; 695b0def88dSAmir Goldstein } else { 696b0def88dSAmir Goldstein /* 697b0def88dSAmir Goldstein * There was an explicit nfs_export=on that resulted 698b0def88dSAmir Goldstein * in this conflict. 699b0def88dSAmir Goldstein */ 700b0def88dSAmir Goldstein pr_info("disabling metacopy due to nfs_export=on\n"); 701b0def88dSAmir Goldstein config->metacopy = false; 702b0def88dSAmir Goldstein } 703b0def88dSAmir Goldstein } 704b0def88dSAmir Goldstein 705d5791044SVivek Goyal return 0; 706e9be9d5eSMiklos Szeredi } 707e9be9d5eSMiklos Szeredi 708e9be9d5eSMiklos Szeredi #define OVL_WORKDIR_NAME "work" 70902bcd157SAmir Goldstein #define OVL_INDEXDIR_NAME "index" 710e9be9d5eSMiklos Szeredi 711ad204488SMiklos Szeredi static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, 7126b8aa129SAmir Goldstein const char *name, bool persist) 713e9be9d5eSMiklos Szeredi { 714ad204488SMiklos Szeredi struct inode *dir = ofs->workbasedir->d_inode; 71508f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 716e9be9d5eSMiklos Szeredi struct dentry *work; 717e9be9d5eSMiklos Szeredi int err; 718e9be9d5eSMiklos Szeredi bool retried = false; 719e9be9d5eSMiklos Szeredi 7205955102cSAl Viro inode_lock_nested(dir, I_MUTEX_PARENT); 721e9be9d5eSMiklos Szeredi retry: 722ad204488SMiklos Szeredi work = lookup_one_len(name, ofs->workbasedir, strlen(name)); 723e9be9d5eSMiklos Szeredi 724e9be9d5eSMiklos Szeredi if (!IS_ERR(work)) { 725c11b9fddSMiklos Szeredi struct iattr attr = { 726c11b9fddSMiklos Szeredi .ia_valid = ATTR_MODE, 72732a3d848SAl Viro .ia_mode = S_IFDIR | 0, 728c11b9fddSMiklos Szeredi }; 729e9be9d5eSMiklos Szeredi 730e9be9d5eSMiklos Szeredi if (work->d_inode) { 731e9be9d5eSMiklos Szeredi err = -EEXIST; 732e9be9d5eSMiklos Szeredi if (retried) 733e9be9d5eSMiklos Szeredi goto out_dput; 734e9be9d5eSMiklos Szeredi 7356b8aa129SAmir Goldstein if (persist) 7366b8aa129SAmir Goldstein goto out_unlock; 7376b8aa129SAmir Goldstein 738e9be9d5eSMiklos Szeredi retried = true; 739235ce9edSAmir Goldstein err = ovl_workdir_cleanup(dir, mnt, work, 0); 740e9be9d5eSMiklos Szeredi dput(work); 741235ce9edSAmir Goldstein if (err == -EINVAL) { 742235ce9edSAmir Goldstein work = ERR_PTR(err); 743235ce9edSAmir Goldstein goto out_unlock; 744235ce9edSAmir Goldstein } 745e9be9d5eSMiklos Szeredi goto retry; 746e9be9d5eSMiklos Szeredi } 747e9be9d5eSMiklos Szeredi 74895a1c815SMiklos Szeredi work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); 74995a1c815SMiklos Szeredi err = PTR_ERR(work); 75095a1c815SMiklos Szeredi if (IS_ERR(work)) 75195a1c815SMiklos Szeredi goto out_err; 752c11b9fddSMiklos Szeredi 753cb348edbSMiklos Szeredi /* 754cb348edbSMiklos Szeredi * Try to remove POSIX ACL xattrs from workdir. We are good if: 755cb348edbSMiklos Szeredi * 756cb348edbSMiklos Szeredi * a) success (there was a POSIX ACL xattr and was removed) 757cb348edbSMiklos Szeredi * b) -ENODATA (there was no POSIX ACL xattr) 758cb348edbSMiklos Szeredi * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) 759cb348edbSMiklos Szeredi * 760cb348edbSMiklos Szeredi * There are various other error values that could effectively 761cb348edbSMiklos Szeredi * mean that the xattr doesn't exist (e.g. -ERANGE is returned 762cb348edbSMiklos Szeredi * if the xattr name is too long), but the set of filesystems 763cb348edbSMiklos Szeredi * allowed as upper are limited to "normal" ones, where checking 764cb348edbSMiklos Szeredi * for the above two errors is sufficient. 765cb348edbSMiklos Szeredi */ 766c11b9fddSMiklos Szeredi err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); 767e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 768c11b9fddSMiklos Szeredi goto out_dput; 769c11b9fddSMiklos Szeredi 770c11b9fddSMiklos Szeredi err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); 771e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 772c11b9fddSMiklos Szeredi goto out_dput; 773c11b9fddSMiklos Szeredi 774c11b9fddSMiklos Szeredi /* Clear any inherited mode bits */ 775c11b9fddSMiklos Szeredi inode_lock(work->d_inode); 776c11b9fddSMiklos Szeredi err = notify_change(work, &attr, NULL); 777c11b9fddSMiklos Szeredi inode_unlock(work->d_inode); 778c11b9fddSMiklos Szeredi if (err) 779c11b9fddSMiklos Szeredi goto out_dput; 7806b8aa129SAmir Goldstein } else { 7816b8aa129SAmir Goldstein err = PTR_ERR(work); 7826b8aa129SAmir Goldstein goto out_err; 783e9be9d5eSMiklos Szeredi } 784e9be9d5eSMiklos Szeredi out_unlock: 7856b8aa129SAmir Goldstein inode_unlock(dir); 786e9be9d5eSMiklos Szeredi return work; 787e9be9d5eSMiklos Szeredi 788e9be9d5eSMiklos Szeredi out_dput: 789e9be9d5eSMiklos Szeredi dput(work); 7906b8aa129SAmir Goldstein out_err: 7911bd0a3aeSlijiazi pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", 792ad204488SMiklos Szeredi ofs->config.workdir, name, -err); 7936b8aa129SAmir Goldstein work = NULL; 794e9be9d5eSMiklos Szeredi goto out_unlock; 795e9be9d5eSMiklos Szeredi } 796e9be9d5eSMiklos Szeredi 79791c77947SMiklos Szeredi static void ovl_unescape(char *s) 79891c77947SMiklos Szeredi { 79991c77947SMiklos Szeredi char *d = s; 80091c77947SMiklos Szeredi 80191c77947SMiklos Szeredi for (;; s++, d++) { 80291c77947SMiklos Szeredi if (*s == '\\') 80391c77947SMiklos Szeredi s++; 80491c77947SMiklos Szeredi *d = *s; 80591c77947SMiklos Szeredi if (!*s) 80691c77947SMiklos Szeredi break; 80791c77947SMiklos Szeredi } 80891c77947SMiklos Szeredi } 80991c77947SMiklos Szeredi 810ab508822SMiklos Szeredi static int ovl_mount_dir_noesc(const char *name, struct path *path) 811ab508822SMiklos Szeredi { 812a78d9f0dSMiklos Szeredi int err = -EINVAL; 813ab508822SMiklos Szeredi 814a78d9f0dSMiklos Szeredi if (!*name) { 8151bd0a3aeSlijiazi pr_err("empty lowerdir\n"); 816a78d9f0dSMiklos Szeredi goto out; 817a78d9f0dSMiklos Szeredi } 818ab508822SMiklos Szeredi err = kern_path(name, LOOKUP_FOLLOW, path); 819ab508822SMiklos Szeredi if (err) { 8201bd0a3aeSlijiazi pr_err("failed to resolve '%s': %i\n", name, err); 821ab508822SMiklos Szeredi goto out; 822ab508822SMiklos Szeredi } 823ab508822SMiklos Szeredi err = -EINVAL; 8247c03b5d4SMiklos Szeredi if (ovl_dentry_weird(path->dentry)) { 8251bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported\n", name); 826ab508822SMiklos Szeredi goto out_put; 827ab508822SMiklos Szeredi } 8282b8c30e9SMiklos Szeredi if (!d_is_dir(path->dentry)) { 8291bd0a3aeSlijiazi pr_err("'%s' not a directory\n", name); 830ab508822SMiklos Szeredi goto out_put; 831ab508822SMiklos Szeredi } 832ab508822SMiklos Szeredi return 0; 833ab508822SMiklos Szeredi 834ab508822SMiklos Szeredi out_put: 8358aafcb59SMiklos Szeredi path_put_init(path); 836ab508822SMiklos Szeredi out: 837ab508822SMiklos Szeredi return err; 838ab508822SMiklos Szeredi } 839ab508822SMiklos Szeredi 840ab508822SMiklos Szeredi static int ovl_mount_dir(const char *name, struct path *path) 841ab508822SMiklos Szeredi { 842ab508822SMiklos Szeredi int err = -ENOMEM; 843ab508822SMiklos Szeredi char *tmp = kstrdup(name, GFP_KERNEL); 844ab508822SMiklos Szeredi 845ab508822SMiklos Szeredi if (tmp) { 846ab508822SMiklos Szeredi ovl_unescape(tmp); 847ab508822SMiklos Szeredi err = ovl_mount_dir_noesc(tmp, path); 8487c03b5d4SMiklos Szeredi 849bccece1eSMiklos Szeredi if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { 8501bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported as upperdir\n", 8517c03b5d4SMiklos Szeredi tmp); 8528aafcb59SMiklos Szeredi path_put_init(path); 8537c03b5d4SMiklos Szeredi err = -EINVAL; 8547c03b5d4SMiklos Szeredi } 855ab508822SMiklos Szeredi kfree(tmp); 856ab508822SMiklos Szeredi } 857ab508822SMiklos Szeredi return err; 858ab508822SMiklos Szeredi } 859ab508822SMiklos Szeredi 8606b2d5fe4SMiklos Szeredi static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, 8616b2d5fe4SMiklos Szeredi const char *name) 8626b2d5fe4SMiklos Szeredi { 8636b2d5fe4SMiklos Szeredi struct kstatfs statfs; 8646b2d5fe4SMiklos Szeredi int err = vfs_statfs(path, &statfs); 8656b2d5fe4SMiklos Szeredi 8666b2d5fe4SMiklos Szeredi if (err) 8671bd0a3aeSlijiazi pr_err("statfs failed on '%s'\n", name); 8686b2d5fe4SMiklos Szeredi else 8696b2d5fe4SMiklos Szeredi ofs->namelen = max(ofs->namelen, statfs.f_namelen); 8706b2d5fe4SMiklos Szeredi 8716b2d5fe4SMiklos Szeredi return err; 8726b2d5fe4SMiklos Szeredi } 8736b2d5fe4SMiklos Szeredi 8746b2d5fe4SMiklos Szeredi static int ovl_lower_dir(const char *name, struct path *path, 875f4288844SMiklos Szeredi struct ovl_fs *ofs, int *stack_depth) 876ab508822SMiklos Szeredi { 877e487d889SAmir Goldstein int fh_type; 878ab508822SMiklos Szeredi int err; 879ab508822SMiklos Szeredi 880a78d9f0dSMiklos Szeredi err = ovl_mount_dir_noesc(name, path); 881ab508822SMiklos Szeredi if (err) 882b8e42a65SMiklos Szeredi return err; 883ab508822SMiklos Szeredi 8846b2d5fe4SMiklos Szeredi err = ovl_check_namelen(path, ofs, name); 8856b2d5fe4SMiklos Szeredi if (err) 886b8e42a65SMiklos Szeredi return err; 8876b2d5fe4SMiklos Szeredi 888ab508822SMiklos Szeredi *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); 889ab508822SMiklos Szeredi 89002bcd157SAmir Goldstein /* 891f168f109SAmir Goldstein * The inodes index feature and NFS export need to encode and decode 892f168f109SAmir Goldstein * file handles, so they require that all layers support them. 89302bcd157SAmir Goldstein */ 894e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(path->dentry->d_sb); 895f168f109SAmir Goldstein if ((ofs->config.nfs_export || 896e487d889SAmir Goldstein (ofs->config.index && ofs->config.upperdir)) && !fh_type) { 89702bcd157SAmir Goldstein ofs->config.index = false; 898f168f109SAmir Goldstein ofs->config.nfs_export = false; 8991bd0a3aeSlijiazi pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", 900f168f109SAmir Goldstein name); 90102bcd157SAmir Goldstein } 90202bcd157SAmir Goldstein 903e487d889SAmir Goldstein /* Check if lower fs has 32bit inode numbers */ 904e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 9050f831ec8SAmir Goldstein ofs->xino_mode = -1; 906e487d889SAmir Goldstein 907ab508822SMiklos Szeredi return 0; 908ab508822SMiklos Szeredi } 909ab508822SMiklos Szeredi 910e9be9d5eSMiklos Szeredi /* Workdir should not be subdir of upperdir and vice versa */ 911e9be9d5eSMiklos Szeredi static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) 912e9be9d5eSMiklos Szeredi { 913e9be9d5eSMiklos Szeredi bool ok = false; 914e9be9d5eSMiklos Szeredi 915e9be9d5eSMiklos Szeredi if (workdir != upperdir) { 916e9be9d5eSMiklos Szeredi ok = (lock_rename(workdir, upperdir) == NULL); 917e9be9d5eSMiklos Szeredi unlock_rename(workdir, upperdir); 918e9be9d5eSMiklos Szeredi } 919e9be9d5eSMiklos Szeredi return ok; 920e9be9d5eSMiklos Szeredi } 921e9be9d5eSMiklos Szeredi 922a78d9f0dSMiklos Szeredi static unsigned int ovl_split_lowerdirs(char *str) 923a78d9f0dSMiklos Szeredi { 924a78d9f0dSMiklos Szeredi unsigned int ctr = 1; 925a78d9f0dSMiklos Szeredi char *s, *d; 926a78d9f0dSMiklos Szeredi 927a78d9f0dSMiklos Szeredi for (s = d = str;; s++, d++) { 928a78d9f0dSMiklos Szeredi if (*s == '\\') { 929a78d9f0dSMiklos Szeredi s++; 930a78d9f0dSMiklos Szeredi } else if (*s == ':') { 931a78d9f0dSMiklos Szeredi *d = '\0'; 932a78d9f0dSMiklos Szeredi ctr++; 933a78d9f0dSMiklos Szeredi continue; 934a78d9f0dSMiklos Szeredi } 935a78d9f0dSMiklos Szeredi *d = *s; 936a78d9f0dSMiklos Szeredi if (!*s) 937a78d9f0dSMiklos Szeredi break; 938a78d9f0dSMiklos Szeredi } 939a78d9f0dSMiklos Szeredi return ctr; 940a78d9f0dSMiklos Szeredi } 941a78d9f0dSMiklos Szeredi 9420c97be22SAndreas Gruenbacher static int __maybe_unused 9430eb45fc3SAndreas Gruenbacher ovl_posix_acl_xattr_get(const struct xattr_handler *handler, 9440eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 9450eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 9460eb45fc3SAndreas Gruenbacher { 9471d88f183SMiklos Szeredi return ovl_xattr_get(dentry, inode, handler->name, buffer, size); 9480eb45fc3SAndreas Gruenbacher } 9490eb45fc3SAndreas Gruenbacher 9500eb45fc3SAndreas Gruenbacher static int __maybe_unused 9510c97be22SAndreas Gruenbacher ovl_posix_acl_xattr_set(const struct xattr_handler *handler, 952d837a49bSMiklos Szeredi struct dentry *dentry, struct inode *inode, 953d837a49bSMiklos Szeredi const char *name, const void *value, 954d837a49bSMiklos Szeredi size_t size, int flags) 955d837a49bSMiklos Szeredi { 956d837a49bSMiklos Szeredi struct dentry *workdir = ovl_workdir(dentry); 95709d8b586SMiklos Szeredi struct inode *realinode = ovl_inode_real(inode); 958d837a49bSMiklos Szeredi struct posix_acl *acl = NULL; 959d837a49bSMiklos Szeredi int err; 960d837a49bSMiklos Szeredi 961d837a49bSMiklos Szeredi /* Check that everything is OK before copy-up */ 962d837a49bSMiklos Szeredi if (value) { 963d837a49bSMiklos Szeredi acl = posix_acl_from_xattr(&init_user_ns, value, size); 964d837a49bSMiklos Szeredi if (IS_ERR(acl)) 965d837a49bSMiklos Szeredi return PTR_ERR(acl); 966d837a49bSMiklos Szeredi } 967d837a49bSMiklos Szeredi err = -EOPNOTSUPP; 968d837a49bSMiklos Szeredi if (!IS_POSIXACL(d_inode(workdir))) 969d837a49bSMiklos Szeredi goto out_acl_release; 970d837a49bSMiklos Szeredi if (!realinode->i_op->set_acl) 971d837a49bSMiklos Szeredi goto out_acl_release; 972d837a49bSMiklos Szeredi if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { 973d837a49bSMiklos Szeredi err = acl ? -EACCES : 0; 974d837a49bSMiklos Szeredi goto out_acl_release; 975d837a49bSMiklos Szeredi } 976d837a49bSMiklos Szeredi err = -EPERM; 977d837a49bSMiklos Szeredi if (!inode_owner_or_capable(inode)) 978d837a49bSMiklos Szeredi goto out_acl_release; 979d837a49bSMiklos Szeredi 980d837a49bSMiklos Szeredi posix_acl_release(acl); 981d837a49bSMiklos Szeredi 982fd3220d3SMiklos Szeredi /* 983fd3220d3SMiklos Szeredi * Check if sgid bit needs to be cleared (actual setacl operation will 984fd3220d3SMiklos Szeredi * be done with mounter's capabilities and so that won't do it for us). 985fd3220d3SMiklos Szeredi */ 986fd3220d3SMiklos Szeredi if (unlikely(inode->i_mode & S_ISGID) && 987fd3220d3SMiklos Szeredi handler->flags == ACL_TYPE_ACCESS && 988fd3220d3SMiklos Szeredi !in_group_p(inode->i_gid) && 989fd3220d3SMiklos Szeredi !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { 990fd3220d3SMiklos Szeredi struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; 991fd3220d3SMiklos Szeredi 992fd3220d3SMiklos Szeredi err = ovl_setattr(dentry, &iattr); 993fd3220d3SMiklos Szeredi if (err) 994fd3220d3SMiklos Szeredi return err; 995fd3220d3SMiklos Szeredi } 996fd3220d3SMiklos Szeredi 9971d88f183SMiklos Szeredi err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); 998ce31513aSMiklos Szeredi if (!err) 99909d8b586SMiklos Szeredi ovl_copyattr(ovl_inode_real(inode), inode); 1000ce31513aSMiklos Szeredi 1001ce31513aSMiklos Szeredi return err; 1002d837a49bSMiklos Szeredi 1003d837a49bSMiklos Szeredi out_acl_release: 1004d837a49bSMiklos Szeredi posix_acl_release(acl); 1005d837a49bSMiklos Szeredi return err; 1006d837a49bSMiklos Szeredi } 1007d837a49bSMiklos 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, 1016d837a49bSMiklos Szeredi struct dentry *dentry, struct inode *inode, 1017d837a49bSMiklos Szeredi const char *name, const void *value, 1018d837a49bSMiklos Szeredi size_t size, int flags) 1019d837a49bSMiklos Szeredi { 102048fab5d7SAmir Goldstein return -EOPNOTSUPP; 1021d837a49bSMiklos Szeredi } 1022d837a49bSMiklos Szeredi 10230eb45fc3SAndreas Gruenbacher static int ovl_other_xattr_get(const struct xattr_handler *handler, 10240eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10250eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10260eb45fc3SAndreas Gruenbacher { 10271d88f183SMiklos Szeredi return ovl_xattr_get(dentry, inode, name, buffer, size); 10280eb45fc3SAndreas Gruenbacher } 10290eb45fc3SAndreas Gruenbacher 10300e585cccSAndreas Gruenbacher static int ovl_other_xattr_set(const struct xattr_handler *handler, 10310e585cccSAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10320e585cccSAndreas Gruenbacher const char *name, const void *value, 10330e585cccSAndreas Gruenbacher size_t size, int flags) 10340e585cccSAndreas Gruenbacher { 10351d88f183SMiklos Szeredi return ovl_xattr_set(dentry, inode, name, value, size, flags); 10360e585cccSAndreas Gruenbacher } 10370e585cccSAndreas Gruenbacher 10380c97be22SAndreas Gruenbacher static const struct xattr_handler __maybe_unused 10390c97be22SAndreas Gruenbacher ovl_posix_acl_access_xattr_handler = { 1040d837a49bSMiklos Szeredi .name = XATTR_NAME_POSIX_ACL_ACCESS, 1041d837a49bSMiklos Szeredi .flags = ACL_TYPE_ACCESS, 10420eb45fc3SAndreas Gruenbacher .get = ovl_posix_acl_xattr_get, 1043d837a49bSMiklos Szeredi .set = ovl_posix_acl_xattr_set, 1044d837a49bSMiklos Szeredi }; 1045d837a49bSMiklos Szeredi 10460c97be22SAndreas Gruenbacher static const struct xattr_handler __maybe_unused 10470c97be22SAndreas Gruenbacher ovl_posix_acl_default_xattr_handler = { 1048d837a49bSMiklos Szeredi .name = XATTR_NAME_POSIX_ACL_DEFAULT, 1049d837a49bSMiklos Szeredi .flags = ACL_TYPE_DEFAULT, 10500eb45fc3SAndreas Gruenbacher .get = ovl_posix_acl_xattr_get, 1051d837a49bSMiklos Szeredi .set = ovl_posix_acl_xattr_set, 1052d837a49bSMiklos Szeredi }; 1053d837a49bSMiklos Szeredi 1054d837a49bSMiklos Szeredi static const struct xattr_handler ovl_own_xattr_handler = { 1055d837a49bSMiklos Szeredi .prefix = OVL_XATTR_PREFIX, 10560eb45fc3SAndreas Gruenbacher .get = ovl_own_xattr_get, 1057d837a49bSMiklos Szeredi .set = ovl_own_xattr_set, 1058d837a49bSMiklos Szeredi }; 1059d837a49bSMiklos Szeredi 1060d837a49bSMiklos Szeredi static const struct xattr_handler ovl_other_xattr_handler = { 1061d837a49bSMiklos Szeredi .prefix = "", /* catch all */ 10620eb45fc3SAndreas Gruenbacher .get = ovl_other_xattr_get, 1063d837a49bSMiklos Szeredi .set = ovl_other_xattr_set, 1064d837a49bSMiklos Szeredi }; 1065d837a49bSMiklos Szeredi 1066d837a49bSMiklos Szeredi static const struct xattr_handler *ovl_xattr_handlers[] = { 10670c97be22SAndreas Gruenbacher #ifdef CONFIG_FS_POSIX_ACL 1068d837a49bSMiklos Szeredi &ovl_posix_acl_access_xattr_handler, 1069d837a49bSMiklos Szeredi &ovl_posix_acl_default_xattr_handler, 10700c97be22SAndreas Gruenbacher #endif 1071d837a49bSMiklos Szeredi &ovl_own_xattr_handler, 1072d837a49bSMiklos Szeredi &ovl_other_xattr_handler, 1073d837a49bSMiklos Szeredi NULL 1074d837a49bSMiklos Szeredi }; 1075d837a49bSMiklos Szeredi 1076146d62e5SAmir Goldstein static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, 1077146d62e5SAmir Goldstein struct inode **ptrap, const char *name) 1078146d62e5SAmir Goldstein { 1079146d62e5SAmir Goldstein struct inode *trap; 1080146d62e5SAmir Goldstein int err; 1081146d62e5SAmir Goldstein 1082146d62e5SAmir Goldstein trap = ovl_get_trap_inode(sb, dir); 10831dac6f5bSArnd Bergmann err = PTR_ERR_OR_ZERO(trap); 10841dac6f5bSArnd Bergmann if (err) { 1085146d62e5SAmir Goldstein if (err == -ELOOP) 10861bd0a3aeSlijiazi pr_err("conflicting %s path\n", name); 1087146d62e5SAmir Goldstein return err; 1088146d62e5SAmir Goldstein } 1089146d62e5SAmir Goldstein 1090146d62e5SAmir Goldstein *ptrap = trap; 1091146d62e5SAmir Goldstein return 0; 1092146d62e5SAmir Goldstein } 1093146d62e5SAmir Goldstein 10940be0bfd2SAmir Goldstein /* 10950be0bfd2SAmir Goldstein * Determine how we treat concurrent use of upperdir/workdir based on the 10960be0bfd2SAmir Goldstein * index feature. This is papering over mount leaks of container runtimes, 10970be0bfd2SAmir Goldstein * for example, an old overlay mount is leaked and now its upperdir is 10980be0bfd2SAmir Goldstein * attempted to be used as a lower layer in a new overlay mount. 10990be0bfd2SAmir Goldstein */ 11000be0bfd2SAmir Goldstein static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) 11010be0bfd2SAmir Goldstein { 11020be0bfd2SAmir Goldstein if (ofs->config.index) { 11031bd0a3aeSlijiazi pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", 11040be0bfd2SAmir Goldstein name); 11050be0bfd2SAmir Goldstein return -EBUSY; 11060be0bfd2SAmir Goldstein } else { 11071bd0a3aeSlijiazi pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", 11080be0bfd2SAmir Goldstein name); 11090be0bfd2SAmir Goldstein return 0; 11100be0bfd2SAmir Goldstein } 11110be0bfd2SAmir Goldstein } 11120be0bfd2SAmir Goldstein 1113146d62e5SAmir Goldstein static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, 1114b8e42a65SMiklos Szeredi struct ovl_layer *upper_layer, struct path *upperpath) 11156ee8acf0SMiklos Szeredi { 11165064975eSMiklos Szeredi struct vfsmount *upper_mnt; 11176ee8acf0SMiklos Szeredi int err; 11186ee8acf0SMiklos Szeredi 1119ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.upperdir, upperpath); 11206ee8acf0SMiklos Szeredi if (err) 11216ee8acf0SMiklos Szeredi goto out; 11226ee8acf0SMiklos Szeredi 11236ee8acf0SMiklos Szeredi /* Upper fs should not be r/o */ 11246ee8acf0SMiklos Szeredi if (sb_rdonly(upperpath->mnt->mnt_sb)) { 11251bd0a3aeSlijiazi pr_err("upper fs is r/o, try multi-lower layers mount\n"); 11266ee8acf0SMiklos Szeredi err = -EINVAL; 11276ee8acf0SMiklos Szeredi goto out; 11286ee8acf0SMiklos Szeredi } 11296ee8acf0SMiklos Szeredi 1130ad204488SMiklos Szeredi err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); 11316ee8acf0SMiklos Szeredi if (err) 11326ee8acf0SMiklos Szeredi goto out; 11336ee8acf0SMiklos Szeredi 1134b8e42a65SMiklos Szeredi err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, 1135146d62e5SAmir Goldstein "upperdir"); 1136146d62e5SAmir Goldstein if (err) 1137146d62e5SAmir Goldstein goto out; 1138146d62e5SAmir Goldstein 11395064975eSMiklos Szeredi upper_mnt = clone_private_mount(upperpath); 11405064975eSMiklos Szeredi err = PTR_ERR(upper_mnt); 11415064975eSMiklos Szeredi if (IS_ERR(upper_mnt)) { 11421bd0a3aeSlijiazi pr_err("failed to clone upperpath\n"); 11435064975eSMiklos Szeredi goto out; 11445064975eSMiklos Szeredi } 11455064975eSMiklos Szeredi 11465064975eSMiklos Szeredi /* Don't inherit atime flags */ 11475064975eSMiklos Szeredi upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); 1148b8e42a65SMiklos Szeredi upper_layer->mnt = upper_mnt; 1149b8e42a65SMiklos Szeredi upper_layer->idx = 0; 1150b8e42a65SMiklos Szeredi upper_layer->fsid = 0; 11518c25741aSMiklos Szeredi 1152654255faSJeffle Xu /* 1153654255faSJeffle Xu * Inherit SB_NOSEC flag from upperdir. 1154654255faSJeffle Xu * 1155654255faSJeffle Xu * This optimization changes behavior when a security related attribute 1156654255faSJeffle Xu * (suid/sgid/security.*) is changed on an underlying layer. This is 1157654255faSJeffle Xu * okay because we don't yet have guarantees in that case, but it will 1158654255faSJeffle Xu * need careful treatment once we want to honour changes to underlying 1159654255faSJeffle Xu * filesystems. 1160654255faSJeffle Xu */ 1161654255faSJeffle Xu if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) 1162654255faSJeffle Xu sb->s_flags |= SB_NOSEC; 1163654255faSJeffle Xu 116408f4c7c8SMiklos Szeredi if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { 11658c25741aSMiklos Szeredi ofs->upperdir_locked = true; 11668c25741aSMiklos Szeredi } else { 11670be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "upperdir"); 11680be0bfd2SAmir Goldstein if (err) 11690be0bfd2SAmir Goldstein goto out; 11708c25741aSMiklos Szeredi } 11718c25741aSMiklos Szeredi 11726ee8acf0SMiklos Szeredi err = 0; 11736ee8acf0SMiklos Szeredi out: 11746ee8acf0SMiklos Szeredi return err; 11756ee8acf0SMiklos Szeredi } 11766ee8acf0SMiklos Szeredi 1177cad218abSAmir Goldstein /* 1178cad218abSAmir Goldstein * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and 1179cad218abSAmir Goldstein * negative values if error is encountered. 1180cad218abSAmir Goldstein */ 1181cad218abSAmir Goldstein static int ovl_check_rename_whiteout(struct dentry *workdir) 1182cad218abSAmir Goldstein { 1183cad218abSAmir Goldstein struct inode *dir = d_inode(workdir); 1184cad218abSAmir Goldstein struct dentry *temp; 1185cad218abSAmir Goldstein struct dentry *dest; 1186cad218abSAmir Goldstein struct dentry *whiteout; 1187cad218abSAmir Goldstein struct name_snapshot name; 1188cad218abSAmir Goldstein int err; 1189cad218abSAmir Goldstein 1190cad218abSAmir Goldstein inode_lock_nested(dir, I_MUTEX_PARENT); 1191cad218abSAmir Goldstein 1192cad218abSAmir Goldstein temp = ovl_create_temp(workdir, OVL_CATTR(S_IFREG | 0)); 1193cad218abSAmir Goldstein err = PTR_ERR(temp); 1194cad218abSAmir Goldstein if (IS_ERR(temp)) 1195cad218abSAmir Goldstein goto out_unlock; 1196cad218abSAmir Goldstein 1197cad218abSAmir Goldstein dest = ovl_lookup_temp(workdir); 1198cad218abSAmir Goldstein err = PTR_ERR(dest); 1199cad218abSAmir Goldstein if (IS_ERR(dest)) { 1200cad218abSAmir Goldstein dput(temp); 1201cad218abSAmir Goldstein goto out_unlock; 1202cad218abSAmir Goldstein } 1203cad218abSAmir Goldstein 1204cad218abSAmir Goldstein /* Name is inline and stable - using snapshot as a copy helper */ 1205cad218abSAmir Goldstein take_dentry_name_snapshot(&name, temp); 1206cad218abSAmir Goldstein err = ovl_do_rename(dir, temp, dir, dest, RENAME_WHITEOUT); 1207cad218abSAmir Goldstein if (err) { 1208cad218abSAmir Goldstein if (err == -EINVAL) 1209cad218abSAmir Goldstein err = 0; 1210cad218abSAmir Goldstein goto cleanup_temp; 1211cad218abSAmir Goldstein } 1212cad218abSAmir Goldstein 1213cad218abSAmir Goldstein whiteout = lookup_one_len(name.name.name, workdir, name.name.len); 1214cad218abSAmir Goldstein err = PTR_ERR(whiteout); 1215cad218abSAmir Goldstein if (IS_ERR(whiteout)) 1216cad218abSAmir Goldstein goto cleanup_temp; 1217cad218abSAmir Goldstein 1218cad218abSAmir Goldstein err = ovl_is_whiteout(whiteout); 1219cad218abSAmir Goldstein 1220cad218abSAmir Goldstein /* Best effort cleanup of whiteout and temp file */ 1221cad218abSAmir Goldstein if (err) 1222cad218abSAmir Goldstein ovl_cleanup(dir, whiteout); 1223cad218abSAmir Goldstein dput(whiteout); 1224cad218abSAmir Goldstein 1225cad218abSAmir Goldstein cleanup_temp: 1226cad218abSAmir Goldstein ovl_cleanup(dir, temp); 1227cad218abSAmir Goldstein release_dentry_name_snapshot(&name); 1228cad218abSAmir Goldstein dput(temp); 1229cad218abSAmir Goldstein dput(dest); 1230cad218abSAmir Goldstein 1231cad218abSAmir Goldstein out_unlock: 1232cad218abSAmir Goldstein inode_unlock(dir); 1233cad218abSAmir Goldstein 1234cad218abSAmir Goldstein return err; 1235cad218abSAmir Goldstein } 1236cad218abSAmir Goldstein 1237c86243b0SVivek Goyal static struct dentry *ovl_lookup_or_create(struct dentry *parent, 1238c86243b0SVivek Goyal const char *name, umode_t mode) 1239c86243b0SVivek Goyal { 1240c86243b0SVivek Goyal size_t len = strlen(name); 1241c86243b0SVivek Goyal struct dentry *child; 1242c86243b0SVivek Goyal 1243c86243b0SVivek Goyal inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); 1244c86243b0SVivek Goyal child = lookup_one_len(name, parent, len); 1245c86243b0SVivek Goyal if (!IS_ERR(child) && !child->d_inode) 1246c86243b0SVivek Goyal child = ovl_create_real(parent->d_inode, child, 1247c86243b0SVivek Goyal OVL_CATTR(mode)); 1248c86243b0SVivek Goyal inode_unlock(parent->d_inode); 1249c86243b0SVivek Goyal dput(parent); 1250c86243b0SVivek Goyal 1251c86243b0SVivek Goyal return child; 1252c86243b0SVivek Goyal } 1253c86243b0SVivek Goyal 1254c86243b0SVivek Goyal /* 1255c86243b0SVivek Goyal * Creates $workdir/work/incompat/volatile/dirty file if it is not already 1256c86243b0SVivek Goyal * present. 1257c86243b0SVivek Goyal */ 1258c86243b0SVivek Goyal static int ovl_create_volatile_dirty(struct ovl_fs *ofs) 1259c86243b0SVivek Goyal { 1260c86243b0SVivek Goyal unsigned int ctr; 1261c86243b0SVivek Goyal struct dentry *d = dget(ofs->workbasedir); 1262c86243b0SVivek Goyal static const char *const volatile_path[] = { 1263c86243b0SVivek Goyal OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" 1264c86243b0SVivek Goyal }; 1265c86243b0SVivek Goyal const char *const *name = volatile_path; 1266c86243b0SVivek Goyal 1267c86243b0SVivek Goyal for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { 1268c86243b0SVivek Goyal d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG); 1269c86243b0SVivek Goyal if (IS_ERR(d)) 1270c86243b0SVivek Goyal return PTR_ERR(d); 1271c86243b0SVivek Goyal } 1272c86243b0SVivek Goyal dput(d); 1273c86243b0SVivek Goyal return 0; 1274c86243b0SVivek Goyal } 1275c86243b0SVivek Goyal 1276146d62e5SAmir Goldstein static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, 1277146d62e5SAmir Goldstein struct path *workpath) 12788ed61dc3SMiklos Szeredi { 127908f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 1280235ce9edSAmir Goldstein struct dentry *temp, *workdir; 1281d80172c2SAmir Goldstein bool rename_whiteout; 1282d80172c2SAmir Goldstein bool d_type; 1283e487d889SAmir Goldstein int fh_type; 12848ed61dc3SMiklos Szeredi int err; 12858ed61dc3SMiklos Szeredi 12862ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 12872ba9d57eSAmir Goldstein if (err) 12882ba9d57eSAmir Goldstein return err; 12892ba9d57eSAmir Goldstein 1290235ce9edSAmir Goldstein workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); 1291235ce9edSAmir Goldstein err = PTR_ERR(workdir); 1292235ce9edSAmir Goldstein if (IS_ERR_OR_NULL(workdir)) 12932ba9d57eSAmir Goldstein goto out; 12948ed61dc3SMiklos Szeredi 1295235ce9edSAmir Goldstein ofs->workdir = workdir; 1296235ce9edSAmir Goldstein 1297146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); 1298146d62e5SAmir Goldstein if (err) 1299146d62e5SAmir Goldstein goto out; 1300146d62e5SAmir Goldstein 13018ed61dc3SMiklos Szeredi /* 13028ed61dc3SMiklos Szeredi * Upper should support d_type, else whiteouts are visible. Given 13038ed61dc3SMiklos Szeredi * workdir and upper are on same fs, we can do iterate_dir() on 13048ed61dc3SMiklos Szeredi * workdir. This check requires successful creation of workdir in 13058ed61dc3SMiklos Szeredi * previous step. 13068ed61dc3SMiklos Szeredi */ 13078ed61dc3SMiklos Szeredi err = ovl_check_d_type_supported(workpath); 13088ed61dc3SMiklos Szeredi if (err < 0) 13092ba9d57eSAmir Goldstein goto out; 13108ed61dc3SMiklos Szeredi 1311d80172c2SAmir Goldstein d_type = err; 1312d80172c2SAmir Goldstein if (!d_type) 13131bd0a3aeSlijiazi pr_warn("upper fs needs to support d_type.\n"); 13148ed61dc3SMiklos Szeredi 13158ed61dc3SMiklos Szeredi /* Check if upper/work fs supports O_TMPFILE */ 1316ad204488SMiklos Szeredi temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); 1317ad204488SMiklos Szeredi ofs->tmpfile = !IS_ERR(temp); 1318ad204488SMiklos Szeredi if (ofs->tmpfile) 13198ed61dc3SMiklos Szeredi dput(temp); 13208ed61dc3SMiklos Szeredi else 13211bd0a3aeSlijiazi pr_warn("upper fs does not support tmpfile.\n"); 13228ed61dc3SMiklos Szeredi 1323cad218abSAmir Goldstein 1324cad218abSAmir Goldstein /* Check if upper/work fs supports RENAME_WHITEOUT */ 1325cad218abSAmir Goldstein err = ovl_check_rename_whiteout(ofs->workdir); 1326cad218abSAmir Goldstein if (err < 0) 1327cad218abSAmir Goldstein goto out; 1328cad218abSAmir Goldstein 1329d80172c2SAmir Goldstein rename_whiteout = err; 1330d80172c2SAmir Goldstein if (!rename_whiteout) 1331cad218abSAmir Goldstein pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); 1332cad218abSAmir Goldstein 13338ed61dc3SMiklos Szeredi /* 13348ed61dc3SMiklos Szeredi * Check if upper/work fs supports trusted.overlay.* xattr 13358ed61dc3SMiklos Szeredi */ 1336610afc0bSMiklos Szeredi err = ovl_do_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); 13378ed61dc3SMiklos Szeredi if (err) { 1338ad204488SMiklos Szeredi ofs->noxattr = true; 1339a683737bSAmir Goldstein ofs->config.index = false; 1340d5791044SVivek Goyal ofs->config.metacopy = false; 13411bd0a3aeSlijiazi pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n"); 13422ba9d57eSAmir Goldstein err = 0; 13438ed61dc3SMiklos Szeredi } else { 1344610afc0bSMiklos Szeredi ovl_do_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); 13458ed61dc3SMiklos Szeredi } 13468ed61dc3SMiklos Szeredi 1347d80172c2SAmir Goldstein /* 1348d80172c2SAmir Goldstein * We allowed sub-optimal upper fs configuration and don't want to break 1349d80172c2SAmir Goldstein * users over kernel upgrade, but we never allowed remote upper fs, so 1350d80172c2SAmir Goldstein * we can enforce strict requirements for remote upper fs. 1351d80172c2SAmir Goldstein */ 1352d80172c2SAmir Goldstein if (ovl_dentry_remote(ofs->workdir) && 1353d80172c2SAmir Goldstein (!d_type || !rename_whiteout || ofs->noxattr)) { 1354d80172c2SAmir Goldstein pr_err("upper fs missing required features.\n"); 1355d80172c2SAmir Goldstein err = -EINVAL; 1356d80172c2SAmir Goldstein goto out; 1357d80172c2SAmir Goldstein } 1358d80172c2SAmir Goldstein 1359c86243b0SVivek Goyal /* 1360c86243b0SVivek Goyal * For volatile mount, create a incompat/volatile/dirty file to keep 1361c86243b0SVivek Goyal * track of it. 1362c86243b0SVivek Goyal */ 1363c86243b0SVivek Goyal if (ofs->config.ovl_volatile) { 1364c86243b0SVivek Goyal err = ovl_create_volatile_dirty(ofs); 1365c86243b0SVivek Goyal if (err < 0) { 1366c86243b0SVivek Goyal pr_err("Failed to create volatile/dirty file.\n"); 1367c86243b0SVivek Goyal goto out; 1368c86243b0SVivek Goyal } 1369c86243b0SVivek Goyal } 1370c86243b0SVivek Goyal 13718ed61dc3SMiklos Szeredi /* Check if upper/work fs supports file handles */ 1372e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); 1373e487d889SAmir Goldstein if (ofs->config.index && !fh_type) { 1374ad204488SMiklos Szeredi ofs->config.index = false; 13751bd0a3aeSlijiazi pr_warn("upper fs does not support file handles, falling back to index=off.\n"); 13768ed61dc3SMiklos Szeredi } 13778ed61dc3SMiklos Szeredi 1378e487d889SAmir Goldstein /* Check if upper fs has 32bit inode numbers */ 1379e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 13800f831ec8SAmir Goldstein ofs->xino_mode = -1; 1381e487d889SAmir Goldstein 1382f168f109SAmir Goldstein /* NFS export of r/w mount depends on index */ 1383f168f109SAmir Goldstein if (ofs->config.nfs_export && !ofs->config.index) { 13841bd0a3aeSlijiazi pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); 1385f168f109SAmir Goldstein ofs->config.nfs_export = false; 1386f168f109SAmir Goldstein } 13872ba9d57eSAmir Goldstein out: 13882ba9d57eSAmir Goldstein mnt_drop_write(mnt); 13892ba9d57eSAmir Goldstein return err; 13908ed61dc3SMiklos Szeredi } 13918ed61dc3SMiklos Szeredi 1392146d62e5SAmir Goldstein static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, 1393146d62e5SAmir Goldstein struct path *upperpath) 1394520d7c86SMiklos Szeredi { 1395520d7c86SMiklos Szeredi int err; 1396bca44b52SMiklos Szeredi struct path workpath = { }; 1397520d7c86SMiklos Szeredi 1398ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.workdir, &workpath); 1399520d7c86SMiklos Szeredi if (err) 1400520d7c86SMiklos Szeredi goto out; 1401520d7c86SMiklos Szeredi 1402520d7c86SMiklos Szeredi err = -EINVAL; 1403bca44b52SMiklos Szeredi if (upperpath->mnt != workpath.mnt) { 14041bd0a3aeSlijiazi pr_err("workdir and upperdir must reside under the same mount\n"); 1405520d7c86SMiklos Szeredi goto out; 1406520d7c86SMiklos Szeredi } 1407bca44b52SMiklos Szeredi if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { 14081bd0a3aeSlijiazi pr_err("workdir and upperdir must be separate subtrees\n"); 1409520d7c86SMiklos Szeredi goto out; 1410520d7c86SMiklos Szeredi } 1411520d7c86SMiklos Szeredi 14128c25741aSMiklos Szeredi ofs->workbasedir = dget(workpath.dentry); 14138c25741aSMiklos Szeredi 14148c25741aSMiklos Szeredi if (ovl_inuse_trylock(ofs->workbasedir)) { 1415ad204488SMiklos Szeredi ofs->workdir_locked = true; 1416520d7c86SMiklos Szeredi } else { 14170be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "workdir"); 14180be0bfd2SAmir Goldstein if (err) 14190be0bfd2SAmir Goldstein goto out; 1420520d7c86SMiklos Szeredi } 1421520d7c86SMiklos Szeredi 14220be0bfd2SAmir Goldstein err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, 14230be0bfd2SAmir Goldstein "workdir"); 14240be0bfd2SAmir Goldstein if (err) 14250be0bfd2SAmir Goldstein goto out; 14260be0bfd2SAmir Goldstein 1427146d62e5SAmir Goldstein err = ovl_make_workdir(sb, ofs, &workpath); 1428bca44b52SMiklos Szeredi 1429520d7c86SMiklos Szeredi out: 1430bca44b52SMiklos Szeredi path_put(&workpath); 1431bca44b52SMiklos Szeredi 1432520d7c86SMiklos Szeredi return err; 1433520d7c86SMiklos Szeredi } 1434520d7c86SMiklos Szeredi 1435146d62e5SAmir Goldstein static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, 1436146d62e5SAmir Goldstein struct ovl_entry *oe, struct path *upperpath) 1437f7e3a7d9SMiklos Szeredi { 143808f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 1439235ce9edSAmir Goldstein struct dentry *indexdir; 1440f7e3a7d9SMiklos Szeredi int err; 1441f7e3a7d9SMiklos Szeredi 14422ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 14432ba9d57eSAmir Goldstein if (err) 14442ba9d57eSAmir Goldstein return err; 14452ba9d57eSAmir Goldstein 1446f7e3a7d9SMiklos Szeredi /* Verify lower root is upper root origin */ 1447610afc0bSMiklos Szeredi err = ovl_verify_origin(ofs, upperpath->dentry, 1448610afc0bSMiklos Szeredi oe->lowerstack[0].dentry, true); 1449f7e3a7d9SMiklos Szeredi if (err) { 14501bd0a3aeSlijiazi pr_err("failed to verify upper root origin\n"); 1451f7e3a7d9SMiklos Szeredi goto out; 1452f7e3a7d9SMiklos Szeredi } 1453f7e3a7d9SMiklos Szeredi 145420396365SAmir Goldstein /* index dir will act also as workdir */ 145520396365SAmir Goldstein iput(ofs->workdir_trap); 145620396365SAmir Goldstein ofs->workdir_trap = NULL; 145720396365SAmir Goldstein dput(ofs->workdir); 1458470c1563SAmir Goldstein ofs->workdir = NULL; 1459235ce9edSAmir Goldstein indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); 1460235ce9edSAmir Goldstein if (IS_ERR(indexdir)) { 1461235ce9edSAmir Goldstein err = PTR_ERR(indexdir); 1462235ce9edSAmir Goldstein } else if (indexdir) { 1463235ce9edSAmir Goldstein ofs->indexdir = indexdir; 1464235ce9edSAmir Goldstein ofs->workdir = dget(indexdir); 146520396365SAmir Goldstein 1466146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, 1467146d62e5SAmir Goldstein "indexdir"); 1468146d62e5SAmir Goldstein if (err) 1469146d62e5SAmir Goldstein goto out; 1470146d62e5SAmir Goldstein 1471ad1d615cSAmir Goldstein /* 1472ad1d615cSAmir Goldstein * Verify upper root is exclusively associated with index dir. 1473ad1d615cSAmir Goldstein * Older kernels stored upper fh in "trusted.overlay.origin" 1474ad1d615cSAmir Goldstein * xattr. If that xattr exists, verify that it is a match to 1475ad1d615cSAmir Goldstein * upper dir file handle. In any case, verify or set xattr 1476ad1d615cSAmir Goldstein * "trusted.overlay.upper" to indicate that index may have 1477ad1d615cSAmir Goldstein * directory entries. 1478ad1d615cSAmir Goldstein */ 1479610afc0bSMiklos Szeredi if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { 1480610afc0bSMiklos Szeredi err = ovl_verify_set_fh(ofs, ofs->indexdir, 1481610afc0bSMiklos Szeredi OVL_XATTR_ORIGIN, 1482ad1d615cSAmir Goldstein upperpath->dentry, true, false); 1483f7e3a7d9SMiklos Szeredi if (err) 14841bd0a3aeSlijiazi pr_err("failed to verify index dir 'origin' xattr\n"); 1485ad1d615cSAmir Goldstein } 1486610afc0bSMiklos Szeredi err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, 1487610afc0bSMiklos Szeredi true); 1488ad1d615cSAmir Goldstein if (err) 14891bd0a3aeSlijiazi pr_err("failed to verify index dir 'upper' xattr\n"); 1490f7e3a7d9SMiklos Szeredi 1491f7e3a7d9SMiklos Szeredi /* Cleanup bad/stale/orphan index entries */ 1492f7e3a7d9SMiklos Szeredi if (!err) 14931eff1a1dSAmir Goldstein err = ovl_indexdir_cleanup(ofs); 1494f7e3a7d9SMiklos Szeredi } 1495ad204488SMiklos Szeredi if (err || !ofs->indexdir) 14961bd0a3aeSlijiazi pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); 1497f7e3a7d9SMiklos Szeredi 1498f7e3a7d9SMiklos Szeredi out: 14992ba9d57eSAmir Goldstein mnt_drop_write(mnt); 1500f7e3a7d9SMiklos Szeredi return err; 1501f7e3a7d9SMiklos Szeredi } 1502f7e3a7d9SMiklos Szeredi 15039df085f3SAmir Goldstein static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) 15045148626bSAmir Goldstein { 15055148626bSAmir Goldstein unsigned int i; 15069df085f3SAmir Goldstein 150708f4c7c8SMiklos Szeredi if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) 15089df085f3SAmir Goldstein return true; 15099df085f3SAmir Goldstein 1510a888db31SAmir Goldstein /* 1511a888db31SAmir Goldstein * We allow using single lower with null uuid for index and nfs_export 1512a888db31SAmir Goldstein * for example to support those features with single lower squashfs. 1513a888db31SAmir Goldstein * To avoid regressions in setups of overlay with re-formatted lower 1514a888db31SAmir Goldstein * squashfs, do not allow decoding origin with lower null uuid unless 1515a888db31SAmir Goldstein * user opted-in to one of the new features that require following the 1516a888db31SAmir Goldstein * lower inode of non-dir upper. 1517a888db31SAmir Goldstein */ 1518a888db31SAmir Goldstein if (!ofs->config.index && !ofs->config.metacopy && !ofs->config.xino && 1519a888db31SAmir Goldstein uuid_is_null(uuid)) 1520a888db31SAmir Goldstein return false; 1521a888db31SAmir Goldstein 15221b81ddddSAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 15239df085f3SAmir Goldstein /* 15249df085f3SAmir Goldstein * We use uuid to associate an overlay lower file handle with a 15259df085f3SAmir Goldstein * lower layer, so we can accept lower fs with null uuid as long 15269df085f3SAmir Goldstein * as all lower layers with null uuid are on the same fs. 15277e63c87fSAmir Goldstein * if we detect multiple lower fs with the same uuid, we 15287e63c87fSAmir Goldstein * disable lower file handle decoding on all of them. 15299df085f3SAmir Goldstein */ 15301b81ddddSAmir Goldstein if (ofs->fs[i].is_lower && 15311b81ddddSAmir Goldstein uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { 153207f1e596SAmir Goldstein ofs->fs[i].bad_uuid = true; 15339df085f3SAmir Goldstein return false; 15349df085f3SAmir Goldstein } 15357e63c87fSAmir Goldstein } 15369df085f3SAmir Goldstein return true; 15379df085f3SAmir Goldstein } 15389df085f3SAmir Goldstein 15399df085f3SAmir Goldstein /* Get a unique fsid for the layer */ 15409df085f3SAmir Goldstein static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) 15419df085f3SAmir Goldstein { 15429df085f3SAmir Goldstein struct super_block *sb = path->mnt->mnt_sb; 15439df085f3SAmir Goldstein unsigned int i; 15445148626bSAmir Goldstein dev_t dev; 15455148626bSAmir Goldstein int err; 15467e63c87fSAmir Goldstein bool bad_uuid = false; 15475148626bSAmir Goldstein 154807f1e596SAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 154907f1e596SAmir Goldstein if (ofs->fs[i].sb == sb) 155007f1e596SAmir Goldstein return i; 15515148626bSAmir Goldstein } 15525148626bSAmir Goldstein 15539df085f3SAmir Goldstein if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { 15547e63c87fSAmir Goldstein bad_uuid = true; 15557e63c87fSAmir Goldstein if (ofs->config.index || ofs->config.nfs_export) { 15569df085f3SAmir Goldstein ofs->config.index = false; 15579df085f3SAmir Goldstein ofs->config.nfs_export = false; 15581bd0a3aeSlijiazi pr_warn("%s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n", 15597e63c87fSAmir Goldstein uuid_is_null(&sb->s_uuid) ? "null" : 15607e63c87fSAmir Goldstein "conflicting", 15619df085f3SAmir Goldstein path->dentry); 15629df085f3SAmir Goldstein } 15637e63c87fSAmir Goldstein } 15649df085f3SAmir Goldstein 15655148626bSAmir Goldstein err = get_anon_bdev(&dev); 15665148626bSAmir Goldstein if (err) { 15671bd0a3aeSlijiazi pr_err("failed to get anonymous bdev for lowerpath\n"); 15685148626bSAmir Goldstein return err; 15695148626bSAmir Goldstein } 15705148626bSAmir Goldstein 157107f1e596SAmir Goldstein ofs->fs[ofs->numfs].sb = sb; 157207f1e596SAmir Goldstein ofs->fs[ofs->numfs].pseudo_dev = dev; 157307f1e596SAmir Goldstein ofs->fs[ofs->numfs].bad_uuid = bad_uuid; 15745148626bSAmir Goldstein 157507f1e596SAmir Goldstein return ofs->numfs++; 15765148626bSAmir Goldstein } 15775148626bSAmir Goldstein 157894375f9dSAmir Goldstein static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, 1579b8e42a65SMiklos Szeredi struct path *stack, unsigned int numlower, 1580b8e42a65SMiklos Szeredi struct ovl_layer *layers) 1581520d7c86SMiklos Szeredi { 1582520d7c86SMiklos Szeredi int err; 1583520d7c86SMiklos Szeredi unsigned int i; 1584520d7c86SMiklos Szeredi 1585520d7c86SMiklos Szeredi err = -ENOMEM; 158607f1e596SAmir Goldstein ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); 158707f1e596SAmir Goldstein if (ofs->fs == NULL) 15885148626bSAmir Goldstein goto out; 15895148626bSAmir Goldstein 159007f1e596SAmir Goldstein /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ 159107f1e596SAmir Goldstein ofs->numfs++; 159207f1e596SAmir Goldstein 159307f1e596SAmir Goldstein /* 1594b7bf9908SAmir Goldstein * All lower layers that share the same fs as upper layer, use the same 1595b7bf9908SAmir Goldstein * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower 1596b7bf9908SAmir Goldstein * only overlay to simplify ovl_fs_free(). 15971b81ddddSAmir Goldstein * is_lower will be set if upper fs is shared with a lower layer. 159807f1e596SAmir Goldstein */ 1599b7bf9908SAmir Goldstein err = get_anon_bdev(&ofs->fs[0].pseudo_dev); 1600b7bf9908SAmir Goldstein if (err) { 1601b7bf9908SAmir Goldstein pr_err("failed to get anonymous bdev for upper fs\n"); 1602b7bf9908SAmir Goldstein goto out; 1603b7bf9908SAmir Goldstein } 1604b7bf9908SAmir Goldstein 160508f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 160608f4c7c8SMiklos Szeredi ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; 16071b81ddddSAmir Goldstein ofs->fs[0].is_lower = false; 160807f1e596SAmir Goldstein } 160907f1e596SAmir Goldstein 1610520d7c86SMiklos Szeredi for (i = 0; i < numlower; i++) { 1611520d7c86SMiklos Szeredi struct vfsmount *mnt; 1612146d62e5SAmir Goldstein struct inode *trap; 16135148626bSAmir Goldstein int fsid; 1614520d7c86SMiklos Szeredi 16159df085f3SAmir Goldstein err = fsid = ovl_get_fsid(ofs, &stack[i]); 16165148626bSAmir Goldstein if (err < 0) 1617520d7c86SMiklos Szeredi goto out; 1618520d7c86SMiklos Szeredi 161924f14009Syoungjun /* 162024f14009Syoungjun * Check if lower root conflicts with this overlay layers before 162124f14009Syoungjun * checking if it is in-use as upperdir/workdir of "another" 162224f14009Syoungjun * mount, because we do not bother to check in ovl_is_inuse() if 162324f14009Syoungjun * the upperdir/workdir is in fact in-use by our 162424f14009Syoungjun * upperdir/workdir. 162524f14009Syoungjun */ 1626146d62e5SAmir Goldstein err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); 1627146d62e5SAmir Goldstein if (err) 1628146d62e5SAmir Goldstein goto out; 1629146d62e5SAmir Goldstein 16300be0bfd2SAmir Goldstein if (ovl_is_inuse(stack[i].dentry)) { 16310be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "lowerdir"); 163224f14009Syoungjun if (err) { 163324f14009Syoungjun iput(trap); 16340be0bfd2SAmir Goldstein goto out; 16350be0bfd2SAmir Goldstein } 163624f14009Syoungjun } 16370be0bfd2SAmir Goldstein 1638520d7c86SMiklos Szeredi mnt = clone_private_mount(&stack[i]); 1639520d7c86SMiklos Szeredi err = PTR_ERR(mnt); 1640520d7c86SMiklos Szeredi if (IS_ERR(mnt)) { 16411bd0a3aeSlijiazi pr_err("failed to clone lowerpath\n"); 1642146d62e5SAmir Goldstein iput(trap); 1643520d7c86SMiklos Szeredi goto out; 1644520d7c86SMiklos Szeredi } 16455148626bSAmir Goldstein 1646520d7c86SMiklos Szeredi /* 1647520d7c86SMiklos Szeredi * Make lower layers R/O. That way fchmod/fchown on lower file 1648520d7c86SMiklos Szeredi * will fail instead of modifying lower fs. 1649520d7c86SMiklos Szeredi */ 1650520d7c86SMiklos Szeredi mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; 1651520d7c86SMiklos Szeredi 165213464165SMiklos Szeredi layers[ofs->numlayer].trap = trap; 165313464165SMiklos Szeredi layers[ofs->numlayer].mnt = mnt; 165413464165SMiklos Szeredi layers[ofs->numlayer].idx = ofs->numlayer; 165513464165SMiklos Szeredi layers[ofs->numlayer].fsid = fsid; 165613464165SMiklos Szeredi layers[ofs->numlayer].fs = &ofs->fs[fsid]; 165794375f9dSAmir Goldstein ofs->numlayer++; 16581b81ddddSAmir Goldstein ofs->fs[fsid].is_lower = true; 1659520d7c86SMiklos Szeredi } 1660e487d889SAmir Goldstein 1661795939a9SAmir Goldstein /* 1662795939a9SAmir Goldstein * When all layers on same fs, overlay can use real inode numbers. 1663926e94d7SAmir Goldstein * With mount option "xino=<on|auto>", mounter declares that there are 1664926e94d7SAmir Goldstein * enough free high bits in underlying fs to hold the unique fsid. 1665795939a9SAmir Goldstein * If overlayfs does encounter underlying inodes using the high xino 1666795939a9SAmir Goldstein * bits reserved for fsid, it emits a warning and uses the original 1667dfe51d47SAmir Goldstein * inode number or a non persistent inode number allocated from a 1668dfe51d47SAmir Goldstein * dedicated range. 1669795939a9SAmir Goldstein */ 167008f4c7c8SMiklos Szeredi if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { 16710f831ec8SAmir Goldstein if (ofs->config.xino == OVL_XINO_ON) 16720f831ec8SAmir Goldstein pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); 16730f831ec8SAmir Goldstein ofs->xino_mode = 0; 167453afcd31SAmir Goldstein } else if (ofs->config.xino == OVL_XINO_OFF) { 167553afcd31SAmir Goldstein ofs->xino_mode = -1; 1676926e94d7SAmir Goldstein } else if (ofs->xino_mode < 0) { 1677795939a9SAmir Goldstein /* 167807f1e596SAmir Goldstein * This is a roundup of number of bits needed for encoding 1679dfe51d47SAmir Goldstein * fsid, where fsid 0 is reserved for upper fs (even with 1680dfe51d47SAmir Goldstein * lower only overlay) +1 extra bit is reserved for the non 1681dfe51d47SAmir Goldstein * persistent inode number range that is used for resolving 1682dfe51d47SAmir Goldstein * xino lower bits overflow. 1683795939a9SAmir Goldstein */ 1684dfe51d47SAmir Goldstein BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); 1685dfe51d47SAmir Goldstein ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; 1686795939a9SAmir Goldstein } 1687795939a9SAmir Goldstein 16880f831ec8SAmir Goldstein if (ofs->xino_mode > 0) { 16891bd0a3aeSlijiazi pr_info("\"xino\" feature enabled using %d upper inode bits.\n", 16900f831ec8SAmir Goldstein ofs->xino_mode); 1691795939a9SAmir Goldstein } 1692e487d889SAmir Goldstein 1693520d7c86SMiklos Szeredi err = 0; 1694520d7c86SMiklos Szeredi out: 1695520d7c86SMiklos Szeredi return err; 1696520d7c86SMiklos Szeredi } 1697520d7c86SMiklos Szeredi 16984155c10aSMiklos Szeredi static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, 1699b8e42a65SMiklos Szeredi const char *lower, unsigned int numlower, 1700b8e42a65SMiklos Szeredi struct ovl_fs *ofs, struct ovl_layer *layers) 170153dbb0b4SMiklos Szeredi { 170253dbb0b4SMiklos Szeredi int err; 17034155c10aSMiklos Szeredi struct path *stack = NULL; 1704b8e42a65SMiklos Szeredi unsigned int i; 17054155c10aSMiklos Szeredi struct ovl_entry *oe; 170653dbb0b4SMiklos Szeredi 1707b8e42a65SMiklos Szeredi if (!ofs->config.upperdir && numlower == 1) { 17081bd0a3aeSlijiazi pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); 1709b8e42a65SMiklos Szeredi return ERR_PTR(-EINVAL); 171053dbb0b4SMiklos Szeredi } 171153dbb0b4SMiklos Szeredi 1712b8e42a65SMiklos Szeredi stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); 171353dbb0b4SMiklos Szeredi if (!stack) 1714b8e42a65SMiklos Szeredi return ERR_PTR(-ENOMEM); 171553dbb0b4SMiklos Szeredi 171653dbb0b4SMiklos Szeredi err = -EINVAL; 1717b8e42a65SMiklos Szeredi for (i = 0; i < numlower; i++) { 1718b8e42a65SMiklos Szeredi err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); 171953dbb0b4SMiklos Szeredi if (err) 17204155c10aSMiklos Szeredi goto out_err; 172153dbb0b4SMiklos Szeredi 172253dbb0b4SMiklos Szeredi lower = strchr(lower, '\0') + 1; 172353dbb0b4SMiklos Szeredi } 172453dbb0b4SMiklos Szeredi 172553dbb0b4SMiklos Szeredi err = -EINVAL; 172653dbb0b4SMiklos Szeredi sb->s_stack_depth++; 172753dbb0b4SMiklos Szeredi if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { 17281bd0a3aeSlijiazi pr_err("maximum fs stacking depth exceeded\n"); 17294155c10aSMiklos Szeredi goto out_err; 173053dbb0b4SMiklos Szeredi } 173153dbb0b4SMiklos Szeredi 1732b8e42a65SMiklos Szeredi err = ovl_get_layers(sb, ofs, stack, numlower, layers); 17334155c10aSMiklos Szeredi if (err) 17344155c10aSMiklos Szeredi goto out_err; 17354155c10aSMiklos Szeredi 17364155c10aSMiklos Szeredi err = -ENOMEM; 17374155c10aSMiklos Szeredi oe = ovl_alloc_entry(numlower); 17384155c10aSMiklos Szeredi if (!oe) 17394155c10aSMiklos Szeredi goto out_err; 17404155c10aSMiklos Szeredi 17414155c10aSMiklos Szeredi for (i = 0; i < numlower; i++) { 17424155c10aSMiklos Szeredi oe->lowerstack[i].dentry = dget(stack[i].dentry); 174394375f9dSAmir Goldstein oe->lowerstack[i].layer = &ofs->layers[i+1]; 17444155c10aSMiklos Szeredi } 174553dbb0b4SMiklos Szeredi 174653dbb0b4SMiklos Szeredi out: 174753dbb0b4SMiklos Szeredi for (i = 0; i < numlower; i++) 174853dbb0b4SMiklos Szeredi path_put(&stack[i]); 174953dbb0b4SMiklos Szeredi kfree(stack); 17504155c10aSMiklos Szeredi 17514155c10aSMiklos Szeredi return oe; 17524155c10aSMiklos Szeredi 17534155c10aSMiklos Szeredi out_err: 17544155c10aSMiklos Szeredi oe = ERR_PTR(err); 175553dbb0b4SMiklos Szeredi goto out; 175653dbb0b4SMiklos Szeredi } 175753dbb0b4SMiklos Szeredi 1758146d62e5SAmir Goldstein /* 1759146d62e5SAmir Goldstein * Check if this layer root is a descendant of: 1760146d62e5SAmir Goldstein * - another layer of this overlayfs instance 1761146d62e5SAmir Goldstein * - upper/work dir of any overlayfs instance 1762146d62e5SAmir Goldstein */ 17630be0bfd2SAmir Goldstein static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, 17640be0bfd2SAmir Goldstein struct dentry *dentry, const char *name) 1765146d62e5SAmir Goldstein { 17669179c21dSMiklos Szeredi struct dentry *next = dentry, *parent; 1767146d62e5SAmir Goldstein int err = 0; 1768146d62e5SAmir Goldstein 17699179c21dSMiklos Szeredi if (!dentry) 1770146d62e5SAmir Goldstein return 0; 1771146d62e5SAmir Goldstein 1772146d62e5SAmir Goldstein parent = dget_parent(next); 17739179c21dSMiklos Szeredi 17749179c21dSMiklos Szeredi /* Walk back ancestors to root (inclusive) looking for traps */ 17759179c21dSMiklos Szeredi while (!err && parent != next) { 17760be0bfd2SAmir Goldstein if (ovl_lookup_trap_inode(sb, parent)) { 1777146d62e5SAmir Goldstein err = -ELOOP; 17781bd0a3aeSlijiazi pr_err("overlapping %s path\n", name); 17790be0bfd2SAmir Goldstein } else if (ovl_is_inuse(parent)) { 17800be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, name); 1781146d62e5SAmir Goldstein } 1782146d62e5SAmir Goldstein next = parent; 17839179c21dSMiklos Szeredi parent = dget_parent(next); 17849179c21dSMiklos Szeredi dput(next); 1785146d62e5SAmir Goldstein } 1786146d62e5SAmir Goldstein 17879179c21dSMiklos Szeredi dput(parent); 1788146d62e5SAmir Goldstein 1789146d62e5SAmir Goldstein return err; 1790146d62e5SAmir Goldstein } 1791146d62e5SAmir Goldstein 1792146d62e5SAmir Goldstein /* 1793146d62e5SAmir Goldstein * Check if any of the layers or work dirs overlap. 1794146d62e5SAmir Goldstein */ 1795146d62e5SAmir Goldstein static int ovl_check_overlapping_layers(struct super_block *sb, 1796146d62e5SAmir Goldstein struct ovl_fs *ofs) 1797146d62e5SAmir Goldstein { 1798146d62e5SAmir Goldstein int i, err; 1799146d62e5SAmir Goldstein 180008f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 180108f4c7c8SMiklos Szeredi err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, 18020be0bfd2SAmir Goldstein "upperdir"); 1803146d62e5SAmir Goldstein if (err) 1804146d62e5SAmir Goldstein return err; 1805146d62e5SAmir Goldstein 1806146d62e5SAmir Goldstein /* 1807146d62e5SAmir Goldstein * Checking workbasedir avoids hitting ovl_is_inuse(parent) of 1808146d62e5SAmir Goldstein * this instance and covers overlapping work and index dirs, 1809146d62e5SAmir Goldstein * unless work or index dir have been moved since created inside 1810146d62e5SAmir Goldstein * workbasedir. In that case, we already have their traps in 1811146d62e5SAmir Goldstein * inode cache and we will catch that case on lookup. 1812146d62e5SAmir Goldstein */ 18130be0bfd2SAmir Goldstein err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir"); 1814146d62e5SAmir Goldstein if (err) 1815146d62e5SAmir Goldstein return err; 1816146d62e5SAmir Goldstein } 1817146d62e5SAmir Goldstein 181894375f9dSAmir Goldstein for (i = 1; i < ofs->numlayer; i++) { 18190be0bfd2SAmir Goldstein err = ovl_check_layer(sb, ofs, 182094375f9dSAmir Goldstein ofs->layers[i].mnt->mnt_root, 1821146d62e5SAmir Goldstein "lowerdir"); 1822146d62e5SAmir Goldstein if (err) 1823146d62e5SAmir Goldstein return err; 1824146d62e5SAmir Goldstein } 1825146d62e5SAmir Goldstein 1826146d62e5SAmir Goldstein return 0; 1827146d62e5SAmir Goldstein } 1828146d62e5SAmir Goldstein 18292effc5c2SAmir Goldstein static struct dentry *ovl_get_root(struct super_block *sb, 18302effc5c2SAmir Goldstein struct dentry *upperdentry, 18312effc5c2SAmir Goldstein struct ovl_entry *oe) 18322effc5c2SAmir Goldstein { 18332effc5c2SAmir Goldstein struct dentry *root; 183462c832edSAmir Goldstein struct ovl_path *lowerpath = &oe->lowerstack[0]; 183562c832edSAmir Goldstein unsigned long ino = d_inode(lowerpath->dentry)->i_ino; 183662c832edSAmir Goldstein int fsid = lowerpath->layer->fsid; 183762c832edSAmir Goldstein struct ovl_inode_params oip = { 183862c832edSAmir Goldstein .upperdentry = upperdentry, 183962c832edSAmir Goldstein .lowerpath = lowerpath, 184062c832edSAmir Goldstein }; 18412effc5c2SAmir Goldstein 18422effc5c2SAmir Goldstein root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); 18432effc5c2SAmir Goldstein if (!root) 18442effc5c2SAmir Goldstein return NULL; 18452effc5c2SAmir Goldstein 18462effc5c2SAmir Goldstein root->d_fsdata = oe; 18472effc5c2SAmir Goldstein 18482effc5c2SAmir Goldstein if (upperdentry) { 184962c832edSAmir Goldstein /* Root inode uses upper st_ino/i_ino */ 185062c832edSAmir Goldstein ino = d_inode(upperdentry)->i_ino; 185162c832edSAmir Goldstein fsid = 0; 18522effc5c2SAmir Goldstein ovl_dentry_set_upper_alias(root); 1853610afc0bSMiklos Szeredi if (ovl_is_impuredir(sb, upperdentry)) 18542effc5c2SAmir Goldstein ovl_set_flag(OVL_IMPURE, d_inode(root)); 18552effc5c2SAmir Goldstein } 18562effc5c2SAmir Goldstein 18572effc5c2SAmir Goldstein /* Root is always merge -> can have whiteouts */ 18582effc5c2SAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); 18592effc5c2SAmir Goldstein ovl_dentry_set_flag(OVL_E_CONNECTED, root); 18602effc5c2SAmir Goldstein ovl_set_upperdata(d_inode(root)); 186162c832edSAmir Goldstein ovl_inode_init(d_inode(root), &oip, ino, fsid); 1862f4288844SMiklos Szeredi ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); 18632effc5c2SAmir Goldstein 18642effc5c2SAmir Goldstein return root; 18652effc5c2SAmir Goldstein } 18662effc5c2SAmir Goldstein 1867e9be9d5eSMiklos Szeredi static int ovl_fill_super(struct super_block *sb, void *data, int silent) 1868e9be9d5eSMiklos Szeredi { 186933006cdfSKees Cook struct path upperpath = { }; 1870e9be9d5eSMiklos Szeredi struct dentry *root_dentry; 18714155c10aSMiklos Szeredi struct ovl_entry *oe; 1872ad204488SMiklos Szeredi struct ovl_fs *ofs; 1873b8e42a65SMiklos Szeredi struct ovl_layer *layers; 187451f8f3c4SKonstantin Khlebnikov struct cred *cred; 1875b8e42a65SMiklos Szeredi char *splitlower = NULL; 1876b8e42a65SMiklos Szeredi unsigned int numlower; 1877e9be9d5eSMiklos Szeredi int err; 1878e9be9d5eSMiklos Szeredi 1879f4288844SMiklos Szeredi sb->s_d_op = &ovl_dentry_operations; 1880f4288844SMiklos Szeredi 1881f45827e8SErez Zadok err = -ENOMEM; 1882ad204488SMiklos Szeredi ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); 1883ad204488SMiklos Szeredi if (!ofs) 1884e9be9d5eSMiklos Szeredi goto out; 1885e9be9d5eSMiklos Szeredi 1886ad204488SMiklos Szeredi ofs->creator_cred = cred = prepare_creds(); 1887c6fe6254SMiklos Szeredi if (!cred) 1888c6fe6254SMiklos Szeredi goto out_err; 1889c6fe6254SMiklos Szeredi 1890c21c839bSChengguang Xu /* Is there a reason anyone would want not to share whiteouts? */ 1891c21c839bSChengguang Xu ofs->share_whiteout = true; 1892c21c839bSChengguang Xu 1893ad204488SMiklos Szeredi ofs->config.index = ovl_index_def; 1894*5830fb6bSPavel Tikhomirov ofs->config.uuid = true; 1895f168f109SAmir Goldstein ofs->config.nfs_export = ovl_nfs_export_def; 1896795939a9SAmir Goldstein ofs->config.xino = ovl_xino_def(); 1897d5791044SVivek Goyal ofs->config.metacopy = ovl_metacopy_def; 1898ad204488SMiklos Szeredi err = ovl_parse_opt((char *) data, &ofs->config); 1899f45827e8SErez Zadok if (err) 1900a9075cdbSMiklos Szeredi goto out_err; 1901f45827e8SErez Zadok 1902e9be9d5eSMiklos Szeredi err = -EINVAL; 1903ad204488SMiklos Szeredi if (!ofs->config.lowerdir) { 190407f2af7bSKonstantin Khlebnikov if (!silent) 19051bd0a3aeSlijiazi pr_err("missing 'lowerdir'\n"); 1906a9075cdbSMiklos Szeredi goto out_err; 190753a08cb9SMiklos Szeredi } 190853a08cb9SMiklos Szeredi 1909b8e42a65SMiklos Szeredi err = -ENOMEM; 1910b8e42a65SMiklos Szeredi splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); 1911b8e42a65SMiklos Szeredi if (!splitlower) 1912b8e42a65SMiklos Szeredi goto out_err; 1913b8e42a65SMiklos Szeredi 1914b8e42a65SMiklos Szeredi numlower = ovl_split_lowerdirs(splitlower); 1915b8e42a65SMiklos Szeredi if (numlower > OVL_MAX_STACK) { 1916b8e42a65SMiklos Szeredi pr_err("too many lower directories, limit is %d\n", 1917b8e42a65SMiklos Szeredi OVL_MAX_STACK); 1918b8e42a65SMiklos Szeredi goto out_err; 1919b8e42a65SMiklos Szeredi } 1920b8e42a65SMiklos Szeredi 1921b8e42a65SMiklos Szeredi layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); 1922b8e42a65SMiklos Szeredi if (!layers) 1923b8e42a65SMiklos Szeredi goto out_err; 1924b8e42a65SMiklos Szeredi 1925b8e42a65SMiklos Szeredi ofs->layers = layers; 1926b8e42a65SMiklos Szeredi /* Layer 0 is reserved for upper even if there's no upper */ 1927b8e42a65SMiklos Szeredi ofs->numlayer = 1; 1928b8e42a65SMiklos Szeredi 192953a08cb9SMiklos Szeredi sb->s_stack_depth = 0; 1930cf9a6784SMiklos Szeredi sb->s_maxbytes = MAX_LFS_FILESIZE; 19314d314f78SAmir Goldstein atomic_long_set(&ofs->last_ino, 1); 1932e487d889SAmir Goldstein /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ 193353afcd31SAmir Goldstein if (ofs->config.xino != OVL_XINO_OFF) { 19340f831ec8SAmir Goldstein ofs->xino_mode = BITS_PER_LONG - 32; 193553afcd31SAmir Goldstein if (!ofs->xino_mode) { 193653afcd31SAmir Goldstein pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); 193753afcd31SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 193853afcd31SAmir Goldstein } 193953afcd31SAmir Goldstein } 1940795939a9SAmir Goldstein 1941146d62e5SAmir Goldstein /* alloc/destroy_inode needed for setting up traps in inode cache */ 1942146d62e5SAmir Goldstein sb->s_op = &ovl_super_operations; 1943146d62e5SAmir Goldstein 1944ad204488SMiklos Szeredi if (ofs->config.upperdir) { 1945ad204488SMiklos Szeredi if (!ofs->config.workdir) { 19461bd0a3aeSlijiazi pr_err("missing 'workdir'\n"); 1947a9075cdbSMiklos Szeredi goto out_err; 1948e9be9d5eSMiklos Szeredi } 1949e9be9d5eSMiklos Szeredi 1950b8e42a65SMiklos Szeredi err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); 195121a3b317SMiklos Szeredi if (err) 1952a9075cdbSMiklos Szeredi goto out_err; 1953d719e8f2SMiklos Szeredi 1954146d62e5SAmir Goldstein err = ovl_get_workdir(sb, ofs, &upperpath); 19558ed61dc3SMiklos Szeredi if (err) 1956a9075cdbSMiklos Szeredi goto out_err; 1957c6fe6254SMiklos Szeredi 1958ad204488SMiklos Szeredi if (!ofs->workdir) 19591751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 19606e88256eSMiklos Szeredi 196108f4c7c8SMiklos Szeredi sb->s_stack_depth = ovl_upper_mnt(ofs)->mnt_sb->s_stack_depth; 196208f4c7c8SMiklos Szeredi sb->s_time_gran = ovl_upper_mnt(ofs)->mnt_sb->s_time_gran; 1963c6fe6254SMiklos Szeredi 196421765194SVivek Goyal } 1965b8e42a65SMiklos Szeredi oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); 19664155c10aSMiklos Szeredi err = PTR_ERR(oe); 19674155c10aSMiklos Szeredi if (IS_ERR(oe)) 1968a9075cdbSMiklos Szeredi goto out_err; 1969e9be9d5eSMiklos Szeredi 197071cbad7eShujianyang /* If the upper fs is nonexistent, we mark overlayfs r/o too */ 197108f4c7c8SMiklos Szeredi if (!ovl_upper_mnt(ofs)) 19721751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 1973e9be9d5eSMiklos Szeredi 1974*5830fb6bSPavel Tikhomirov if (!ofs->config.uuid && ofs->numfs > 1) { 1975*5830fb6bSPavel Tikhomirov pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); 1976*5830fb6bSPavel Tikhomirov ofs->config.uuid = true; 1977*5830fb6bSPavel Tikhomirov } 1978*5830fb6bSPavel Tikhomirov 1979470c1563SAmir Goldstein if (!ovl_force_readonly(ofs) && ofs->config.index) { 1980146d62e5SAmir Goldstein err = ovl_get_indexdir(sb, ofs, oe, &upperpath); 198154fb347eSAmir Goldstein if (err) 19824155c10aSMiklos Szeredi goto out_free_oe; 19836e88256eSMiklos Szeredi 1984972d0093SAmir Goldstein /* Force r/o mount with no index dir */ 198520396365SAmir Goldstein if (!ofs->indexdir) 19861751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 198702bcd157SAmir Goldstein } 198802bcd157SAmir Goldstein 1989146d62e5SAmir Goldstein err = ovl_check_overlapping_layers(sb, ofs); 1990146d62e5SAmir Goldstein if (err) 1991146d62e5SAmir Goldstein goto out_free_oe; 1992146d62e5SAmir Goldstein 1993972d0093SAmir Goldstein /* Show index=off in /proc/mounts for forced r/o mount */ 1994f168f109SAmir Goldstein if (!ofs->indexdir) { 1995ad204488SMiklos Szeredi ofs->config.index = false; 199608f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { 19971bd0a3aeSlijiazi pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); 1998f168f109SAmir Goldstein ofs->config.nfs_export = false; 1999f168f109SAmir Goldstein } 2000f168f109SAmir Goldstein } 200102bcd157SAmir Goldstein 2002d5791044SVivek Goyal if (ofs->config.metacopy && ofs->config.nfs_export) { 20031bd0a3aeSlijiazi pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); 2004d5791044SVivek Goyal ofs->config.nfs_export = false; 2005d5791044SVivek Goyal } 2006d5791044SVivek Goyal 20078383f174SAmir Goldstein if (ofs->config.nfs_export) 20088383f174SAmir Goldstein sb->s_export_op = &ovl_export_operations; 20098383f174SAmir Goldstein 201051f8f3c4SKonstantin Khlebnikov /* Never override disk quota limits or use reserved space */ 201151f8f3c4SKonstantin Khlebnikov cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); 201251f8f3c4SKonstantin Khlebnikov 2013655042ccSVivek Goyal sb->s_magic = OVERLAYFS_SUPER_MAGIC; 2014655042ccSVivek Goyal sb->s_xattr = ovl_xattr_handlers; 2015ad204488SMiklos Szeredi sb->s_fs_info = ofs; 2016de2a4a50SMiklos Szeredi sb->s_flags |= SB_POSIXACL; 201732b1924bSKonstantin Khlebnikov sb->s_iflags |= SB_I_SKIP_SYNC; 2018655042ccSVivek Goyal 2019c6fe6254SMiklos Szeredi err = -ENOMEM; 20202effc5c2SAmir Goldstein root_dentry = ovl_get_root(sb, upperpath.dentry, oe); 2021e9be9d5eSMiklos Szeredi if (!root_dentry) 20224155c10aSMiklos Szeredi goto out_free_oe; 2023e9be9d5eSMiklos Szeredi 2024e9be9d5eSMiklos Szeredi mntput(upperpath.mnt); 2025b8e42a65SMiklos Szeredi kfree(splitlower); 2026ed06e069SMiklos Szeredi 2027e9be9d5eSMiklos Szeredi sb->s_root = root_dentry; 2028e9be9d5eSMiklos Szeredi 2029e9be9d5eSMiklos Szeredi return 0; 2030e9be9d5eSMiklos Szeredi 20314155c10aSMiklos Szeredi out_free_oe: 20324155c10aSMiklos Szeredi ovl_entry_stack_free(oe); 2033b9343632SChandan Rajendra kfree(oe); 20344155c10aSMiklos Szeredi out_err: 2035b8e42a65SMiklos Szeredi kfree(splitlower); 2036e9be9d5eSMiklos Szeredi path_put(&upperpath); 2037ad204488SMiklos Szeredi ovl_free_fs(ofs); 2038e9be9d5eSMiklos Szeredi out: 2039e9be9d5eSMiklos Szeredi return err; 2040e9be9d5eSMiklos Szeredi } 2041e9be9d5eSMiklos Szeredi 2042e9be9d5eSMiklos Szeredi static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, 2043e9be9d5eSMiklos Szeredi const char *dev_name, void *raw_data) 2044e9be9d5eSMiklos Szeredi { 2045e9be9d5eSMiklos Szeredi return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); 2046e9be9d5eSMiklos Szeredi } 2047e9be9d5eSMiklos Szeredi 2048e9be9d5eSMiklos Szeredi static struct file_system_type ovl_fs_type = { 2049e9be9d5eSMiklos Szeredi .owner = THIS_MODULE, 2050ef94b186SMiklos Szeredi .name = "overlay", 2051e9be9d5eSMiklos Szeredi .mount = ovl_mount, 2052e9be9d5eSMiklos Szeredi .kill_sb = kill_anon_super, 2053e9be9d5eSMiklos Szeredi }; 2054ef94b186SMiklos Szeredi MODULE_ALIAS_FS("overlay"); 2055e9be9d5eSMiklos Szeredi 205613cf199dSAmir Goldstein static void ovl_inode_init_once(void *foo) 205713cf199dSAmir Goldstein { 205813cf199dSAmir Goldstein struct ovl_inode *oi = foo; 205913cf199dSAmir Goldstein 206013cf199dSAmir Goldstein inode_init_once(&oi->vfs_inode); 206113cf199dSAmir Goldstein } 206213cf199dSAmir Goldstein 2063e9be9d5eSMiklos Szeredi static int __init ovl_init(void) 2064e9be9d5eSMiklos Szeredi { 206513cf199dSAmir Goldstein int err; 206613cf199dSAmir Goldstein 206713cf199dSAmir Goldstein ovl_inode_cachep = kmem_cache_create("ovl_inode", 206813cf199dSAmir Goldstein sizeof(struct ovl_inode), 0, 206913cf199dSAmir Goldstein (SLAB_RECLAIM_ACCOUNT| 207013cf199dSAmir Goldstein SLAB_MEM_SPREAD|SLAB_ACCOUNT), 207113cf199dSAmir Goldstein ovl_inode_init_once); 207213cf199dSAmir Goldstein if (ovl_inode_cachep == NULL) 207313cf199dSAmir Goldstein return -ENOMEM; 207413cf199dSAmir Goldstein 20752406a307SJiufei Xue err = ovl_aio_request_cache_init(); 20762406a307SJiufei Xue if (!err) { 207713cf199dSAmir Goldstein err = register_filesystem(&ovl_fs_type); 20782406a307SJiufei Xue if (!err) 20792406a307SJiufei Xue return 0; 20802406a307SJiufei Xue 20812406a307SJiufei Xue ovl_aio_request_cache_destroy(); 20822406a307SJiufei Xue } 208313cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 208413cf199dSAmir Goldstein 208513cf199dSAmir Goldstein return err; 2086e9be9d5eSMiklos Szeredi } 2087e9be9d5eSMiklos Szeredi 2088e9be9d5eSMiklos Szeredi static void __exit ovl_exit(void) 2089e9be9d5eSMiklos Szeredi { 2090e9be9d5eSMiklos Szeredi unregister_filesystem(&ovl_fs_type); 209113cf199dSAmir Goldstein 209213cf199dSAmir Goldstein /* 209313cf199dSAmir Goldstein * Make sure all delayed rcu free inodes are flushed before we 209413cf199dSAmir Goldstein * destroy cache. 209513cf199dSAmir Goldstein */ 209613cf199dSAmir Goldstein rcu_barrier(); 209713cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 20982406a307SJiufei Xue ovl_aio_request_cache_destroy(); 2099e9be9d5eSMiklos Szeredi } 2100e9be9d5eSMiklos Szeredi 2101e9be9d5eSMiklos Szeredi module_init(ovl_init); 2102e9be9d5eSMiklos Szeredi module_exit(ovl_exit); 2103