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 { 82cef4cbffSMiklos Szeredi struct dentry *real = NULL, *lower; 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 101cef4cbffSMiklos Szeredi lower = ovl_dentry_lowerdata(dentry); 102cef4cbffSMiklos Szeredi if (!lower) 103d101a125SMiklos Szeredi goto bug; 104cef4cbffSMiklos Szeredi real = lower; 105d101a125SMiklos Szeredi 106c4fcfc16SMiklos Szeredi /* Handle recursion */ 107fb16043bSMiklos Szeredi real = d_real(real, inode); 108c4fcfc16SMiklos Szeredi 109d101a125SMiklos Szeredi if (!inode || inode == d_inode(real)) 110d101a125SMiklos Szeredi return real; 111d101a125SMiklos Szeredi bug: 112cef4cbffSMiklos Szeredi WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", 113cef4cbffSMiklos Szeredi __func__, dentry, inode ? inode->i_sb->s_id : "NULL", 114cef4cbffSMiklos Szeredi inode ? inode->i_ino : 0, real, 115cef4cbffSMiklos Szeredi real && d_inode(real) ? d_inode(real)->i_ino : 0); 116d101a125SMiklos Szeredi return dentry; 117d101a125SMiklos Szeredi } 118d101a125SMiklos Szeredi 1193bb7df92SMiklos Szeredi static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) 1203bb7df92SMiklos Szeredi { 1213bb7df92SMiklos Szeredi int ret = 1; 1223bb7df92SMiklos Szeredi 1233bb7df92SMiklos Szeredi if (weak) { 1243bb7df92SMiklos Szeredi if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) 1253bb7df92SMiklos Szeredi ret = d->d_op->d_weak_revalidate(d, flags); 1263bb7df92SMiklos Szeredi } else if (d->d_flags & DCACHE_OP_REVALIDATE) { 1273bb7df92SMiklos Szeredi ret = d->d_op->d_revalidate(d, flags); 1283bb7df92SMiklos Szeredi if (!ret) { 1293bb7df92SMiklos Szeredi if (!(flags & LOOKUP_RCU)) 1303bb7df92SMiklos Szeredi d_invalidate(d); 1313bb7df92SMiklos Szeredi ret = -ESTALE; 1323bb7df92SMiklos Szeredi } 1333bb7df92SMiklos Szeredi } 1343bb7df92SMiklos Szeredi return ret; 1353bb7df92SMiklos Szeredi } 1363bb7df92SMiklos Szeredi 1373bb7df92SMiklos Szeredi static int ovl_dentry_revalidate_common(struct dentry *dentry, 1383bb7df92SMiklos Szeredi unsigned int flags, bool weak) 1397c03b5d4SMiklos Szeredi { 1407c03b5d4SMiklos Szeredi struct ovl_entry *oe = dentry->d_fsdata; 141bccece1eSMiklos Szeredi struct dentry *upper; 1427c03b5d4SMiklos Szeredi unsigned int i; 1437c03b5d4SMiklos Szeredi int ret = 1; 1447c03b5d4SMiklos Szeredi 145bccece1eSMiklos Szeredi upper = ovl_dentry_upper(dentry); 146bccece1eSMiklos Szeredi if (upper) 147bccece1eSMiklos Szeredi ret = ovl_revalidate_real(upper, flags, weak); 148bccece1eSMiklos Szeredi 1493bb7df92SMiklos Szeredi for (i = 0; ret > 0 && i < oe->numlower; i++) { 1503bb7df92SMiklos Szeredi ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, 1513bb7df92SMiklos Szeredi weak); 1523bb7df92SMiklos Szeredi } 1537c03b5d4SMiklos Szeredi return ret; 1547c03b5d4SMiklos Szeredi } 1553bb7df92SMiklos Szeredi 1563bb7df92SMiklos Szeredi static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) 1573bb7df92SMiklos Szeredi { 1583bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, false); 1597c03b5d4SMiklos Szeredi } 1607c03b5d4SMiklos Szeredi 1617c03b5d4SMiklos Szeredi static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) 1627c03b5d4SMiklos Szeredi { 1633bb7df92SMiklos Szeredi return ovl_dentry_revalidate_common(dentry, flags, true); 1647c03b5d4SMiklos Szeredi } 1657c03b5d4SMiklos Szeredi 166e9be9d5eSMiklos Szeredi static const struct dentry_operations ovl_dentry_operations = { 167e9be9d5eSMiklos Szeredi .d_release = ovl_dentry_release, 168d101a125SMiklos Szeredi .d_real = ovl_d_real, 1697c03b5d4SMiklos Szeredi .d_revalidate = ovl_dentry_revalidate, 1707c03b5d4SMiklos Szeredi .d_weak_revalidate = ovl_dentry_weak_revalidate, 1717c03b5d4SMiklos Szeredi }; 1727c03b5d4SMiklos Szeredi 17313cf199dSAmir Goldstein static struct kmem_cache *ovl_inode_cachep; 17413cf199dSAmir Goldstein 17513cf199dSAmir Goldstein static struct inode *ovl_alloc_inode(struct super_block *sb) 17613cf199dSAmir Goldstein { 177fd60b288SMuchun Song struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); 17813cf199dSAmir Goldstein 179b3885bd6SHirofumi Nakagawa if (!oi) 180b3885bd6SHirofumi Nakagawa return NULL; 181b3885bd6SHirofumi Nakagawa 18204a01ac7SMiklos Szeredi oi->cache = NULL; 183cf31c463SMiklos Szeredi oi->redirect = NULL; 18404a01ac7SMiklos Szeredi oi->version = 0; 18513c72075SMiklos Szeredi oi->flags = 0; 18609d8b586SMiklos Szeredi oi->__upperdentry = NULL; 18725b7713aSMiklos Szeredi oi->lower = NULL; 1882664bd08SVivek Goyal oi->lowerdata = NULL; 189a015dafcSAmir Goldstein mutex_init(&oi->lock); 19025b7713aSMiklos Szeredi 19113cf199dSAmir Goldstein return &oi->vfs_inode; 19213cf199dSAmir Goldstein } 19313cf199dSAmir Goldstein 1940b269dedSAl Viro static void ovl_free_inode(struct inode *inode) 19513cf199dSAmir Goldstein { 1960b269dedSAl Viro struct ovl_inode *oi = OVL_I(inode); 19713cf199dSAmir Goldstein 1980b269dedSAl Viro kfree(oi->redirect); 1990b269dedSAl Viro mutex_destroy(&oi->lock); 2000b269dedSAl Viro kmem_cache_free(ovl_inode_cachep, oi); 20113cf199dSAmir Goldstein } 20213cf199dSAmir Goldstein 20313cf199dSAmir Goldstein static void ovl_destroy_inode(struct inode *inode) 20413cf199dSAmir Goldstein { 20509d8b586SMiklos Szeredi struct ovl_inode *oi = OVL_I(inode); 20609d8b586SMiklos Szeredi 20709d8b586SMiklos Szeredi dput(oi->__upperdentry); 20831747edaSAmir Goldstein iput(oi->lower); 2092664bd08SVivek Goyal if (S_ISDIR(inode->i_mode)) 2104edb83bbSMiklos Szeredi ovl_dir_cache_free(inode); 2112664bd08SVivek Goyal else 2122664bd08SVivek Goyal iput(oi->lowerdata); 21313cf199dSAmir Goldstein } 21413cf199dSAmir Goldstein 215ad204488SMiklos Szeredi static void ovl_free_fs(struct ovl_fs *ofs) 216e9be9d5eSMiklos Szeredi { 217df820f8dSMiklos Szeredi struct vfsmount **mounts; 218dd662667SMiklos Szeredi unsigned i; 219e9be9d5eSMiklos Szeredi 2200be0bfd2SAmir Goldstein iput(ofs->workbasedir_trap); 221146d62e5SAmir Goldstein iput(ofs->indexdir_trap); 222146d62e5SAmir Goldstein iput(ofs->workdir_trap); 223c21c839bSChengguang Xu dput(ofs->whiteout); 224ad204488SMiklos Szeredi dput(ofs->indexdir); 225ad204488SMiklos Szeredi dput(ofs->workdir); 226ad204488SMiklos Szeredi if (ofs->workdir_locked) 227ad204488SMiklos Szeredi ovl_inuse_unlock(ofs->workbasedir); 228ad204488SMiklos Szeredi dput(ofs->workbasedir); 229ad204488SMiklos Szeredi if (ofs->upperdir_locked) 23008f4c7c8SMiklos Szeredi ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); 231df820f8dSMiklos Szeredi 232df820f8dSMiklos Szeredi /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ 233df820f8dSMiklos Szeredi mounts = (struct vfsmount **) ofs->layers; 234b8e42a65SMiklos Szeredi for (i = 0; i < ofs->numlayer; i++) { 23594375f9dSAmir Goldstein iput(ofs->layers[i].trap); 236df820f8dSMiklos Szeredi mounts[i] = ofs->layers[i].mnt; 237146d62e5SAmir Goldstein } 238df820f8dSMiklos Szeredi kern_unmount_array(mounts, ofs->numlayer); 23994375f9dSAmir Goldstein kfree(ofs->layers); 240b7bf9908SAmir Goldstein for (i = 0; i < ofs->numfs; i++) 24107f1e596SAmir Goldstein free_anon_bdev(ofs->fs[i].pseudo_dev); 24207f1e596SAmir Goldstein kfree(ofs->fs); 243e9be9d5eSMiklos Szeredi 244ad204488SMiklos Szeredi kfree(ofs->config.lowerdir); 245ad204488SMiklos Szeredi kfree(ofs->config.upperdir); 246ad204488SMiklos Szeredi kfree(ofs->config.workdir); 247438c84c2SMiklos Szeredi kfree(ofs->config.redirect_mode); 248ad204488SMiklos Szeredi if (ofs->creator_cred) 249ad204488SMiklos Szeredi put_cred(ofs->creator_cred); 250ad204488SMiklos Szeredi kfree(ofs); 251e9be9d5eSMiklos Szeredi } 252e9be9d5eSMiklos Szeredi 253a9075cdbSMiklos Szeredi static void ovl_put_super(struct super_block *sb) 254a9075cdbSMiklos Szeredi { 255a9075cdbSMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 256a9075cdbSMiklos Szeredi 257a9075cdbSMiklos Szeredi ovl_free_fs(ofs); 258a9075cdbSMiklos Szeredi } 259a9075cdbSMiklos Szeredi 260e8d4bfe3SChengguang Xu /* Sync real dirty inodes in upper filesystem (if it exists) */ 261e593b2bfSAmir Goldstein static int ovl_sync_fs(struct super_block *sb, int wait) 262e593b2bfSAmir Goldstein { 263ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 264e593b2bfSAmir Goldstein struct super_block *upper_sb; 265e593b2bfSAmir Goldstein int ret; 266e593b2bfSAmir Goldstein 267335d3fc5SSargun Dhillon ret = ovl_sync_status(ofs); 268335d3fc5SSargun Dhillon /* 269335d3fc5SSargun Dhillon * We have to always set the err, because the return value isn't 270335d3fc5SSargun Dhillon * checked in syncfs, and instead indirectly return an error via 271335d3fc5SSargun Dhillon * the sb's writeback errseq, which VFS inspects after this call. 272335d3fc5SSargun Dhillon */ 273335d3fc5SSargun Dhillon if (ret < 0) { 274335d3fc5SSargun Dhillon errseq_set(&sb->s_wb_err, -EIO); 275335d3fc5SSargun Dhillon return -EIO; 276335d3fc5SSargun Dhillon } 277e8d4bfe3SChengguang Xu 278335d3fc5SSargun Dhillon if (!ret) 279335d3fc5SSargun Dhillon return ret; 280335d3fc5SSargun Dhillon 281e8d4bfe3SChengguang Xu /* 28232b1924bSKonstantin Khlebnikov * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). 28332b1924bSKonstantin Khlebnikov * All the super blocks will be iterated, including upper_sb. 284e8d4bfe3SChengguang Xu * 285e8d4bfe3SChengguang Xu * If this is a syncfs(2) call, then we do need to call 286e8d4bfe3SChengguang Xu * sync_filesystem() on upper_sb, but enough if we do it when being 287e8d4bfe3SChengguang Xu * called with wait == 1. 288e8d4bfe3SChengguang Xu */ 289e8d4bfe3SChengguang Xu if (!wait) 290e593b2bfSAmir Goldstein return 0; 291e593b2bfSAmir Goldstein 29208f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 293e8d4bfe3SChengguang Xu 294e593b2bfSAmir Goldstein down_read(&upper_sb->s_umount); 295e8d4bfe3SChengguang Xu ret = sync_filesystem(upper_sb); 296e593b2bfSAmir Goldstein up_read(&upper_sb->s_umount); 297e8d4bfe3SChengguang Xu 298e593b2bfSAmir Goldstein return ret; 299e593b2bfSAmir Goldstein } 300e593b2bfSAmir Goldstein 301cc259639SAndy Whitcroft /** 302cc259639SAndy Whitcroft * ovl_statfs 303cc259639SAndy Whitcroft * @sb: The overlayfs super block 304cc259639SAndy Whitcroft * @buf: The struct kstatfs to fill in with stats 305cc259639SAndy Whitcroft * 306cc259639SAndy Whitcroft * Get the filesystem statistics. As writes always target the upper layer 3074ebc5818SMiklos Szeredi * filesystem pass the statfs to the upper filesystem (if it exists) 308cc259639SAndy Whitcroft */ 309cc259639SAndy Whitcroft static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) 310cc259639SAndy Whitcroft { 311cc259639SAndy Whitcroft struct ovl_fs *ofs = dentry->d_sb->s_fs_info; 312cc259639SAndy Whitcroft struct dentry *root_dentry = dentry->d_sb->s_root; 313cc259639SAndy Whitcroft struct path path; 314cc259639SAndy Whitcroft int err; 315cc259639SAndy Whitcroft 3164ebc5818SMiklos Szeredi ovl_path_real(root_dentry, &path); 317cc259639SAndy Whitcroft 318cc259639SAndy Whitcroft err = vfs_statfs(&path, buf); 319cc259639SAndy Whitcroft if (!err) { 3206b2d5fe4SMiklos Szeredi buf->f_namelen = ofs->namelen; 321cc259639SAndy Whitcroft buf->f_type = OVERLAYFS_SUPER_MAGIC; 322cc259639SAndy Whitcroft } 323cc259639SAndy Whitcroft 324cc259639SAndy Whitcroft return err; 325cc259639SAndy Whitcroft } 326cc259639SAndy Whitcroft 32702bcd157SAmir Goldstein /* Will this overlay be forced to mount/remount ro? */ 328ad204488SMiklos Szeredi static bool ovl_force_readonly(struct ovl_fs *ofs) 32902bcd157SAmir Goldstein { 33008f4c7c8SMiklos Szeredi return (!ovl_upper_mnt(ofs) || !ofs->workdir); 33102bcd157SAmir Goldstein } 33202bcd157SAmir Goldstein 333438c84c2SMiklos Szeredi static const char *ovl_redirect_mode_def(void) 334438c84c2SMiklos Szeredi { 335438c84c2SMiklos Szeredi return ovl_redirect_dir_def ? "on" : "off"; 336438c84c2SMiklos Szeredi } 337438c84c2SMiklos Szeredi 338795939a9SAmir Goldstein static const char * const ovl_xino_str[] = { 339795939a9SAmir Goldstein "off", 340795939a9SAmir Goldstein "auto", 341795939a9SAmir Goldstein "on", 342795939a9SAmir Goldstein }; 343795939a9SAmir Goldstein 344795939a9SAmir Goldstein static inline int ovl_xino_def(void) 345795939a9SAmir Goldstein { 346795939a9SAmir Goldstein return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF; 347795939a9SAmir Goldstein } 348795939a9SAmir Goldstein 349f45827e8SErez Zadok /** 350f45827e8SErez Zadok * ovl_show_options 351f45827e8SErez Zadok * 352f45827e8SErez Zadok * Prints the mount options for a given superblock. 353f45827e8SErez Zadok * Returns zero; does not fail. 354f45827e8SErez Zadok */ 355f45827e8SErez Zadok static int ovl_show_options(struct seq_file *m, struct dentry *dentry) 356f45827e8SErez Zadok { 357f45827e8SErez Zadok struct super_block *sb = dentry->d_sb; 358ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 359f45827e8SErez Zadok 360ad204488SMiklos Szeredi seq_show_option(m, "lowerdir", ofs->config.lowerdir); 361ad204488SMiklos Szeredi if (ofs->config.upperdir) { 362ad204488SMiklos Szeredi seq_show_option(m, "upperdir", ofs->config.upperdir); 363ad204488SMiklos Szeredi seq_show_option(m, "workdir", ofs->config.workdir); 36453a08cb9SMiklos Szeredi } 365ad204488SMiklos Szeredi if (ofs->config.default_permissions) 3668d3095f4SMiklos Szeredi seq_puts(m, ",default_permissions"); 367438c84c2SMiklos Szeredi if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) 368438c84c2SMiklos Szeredi seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); 369ad204488SMiklos Szeredi if (ofs->config.index != ovl_index_def) 370438c84c2SMiklos Szeredi seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); 3715830fb6bSPavel Tikhomirov if (!ofs->config.uuid) 3725830fb6bSPavel Tikhomirov seq_puts(m, ",uuid=off"); 373f168f109SAmir Goldstein if (ofs->config.nfs_export != ovl_nfs_export_def) 374f168f109SAmir Goldstein seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? 375f168f109SAmir Goldstein "on" : "off"); 3760f831ec8SAmir Goldstein if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(sb)) 377795939a9SAmir Goldstein seq_printf(m, ",xino=%s", ovl_xino_str[ofs->config.xino]); 378d5791044SVivek Goyal if (ofs->config.metacopy != ovl_metacopy_def) 379d5791044SVivek Goyal seq_printf(m, ",metacopy=%s", 380d5791044SVivek Goyal ofs->config.metacopy ? "on" : "off"); 381c86243b0SVivek Goyal if (ofs->config.ovl_volatile) 382c86243b0SVivek Goyal seq_puts(m, ",volatile"); 383321b46b9SGiuseppe Scrivano if (ofs->config.userxattr) 384321b46b9SGiuseppe Scrivano seq_puts(m, ",userxattr"); 385f45827e8SErez Zadok return 0; 386f45827e8SErez Zadok } 387f45827e8SErez Zadok 3883cdf6fe9SSeunghun Lee static int ovl_remount(struct super_block *sb, int *flags, char *data) 3893cdf6fe9SSeunghun Lee { 390ad204488SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 391399c109dSChengguang Xu struct super_block *upper_sb; 392399c109dSChengguang Xu int ret = 0; 3933cdf6fe9SSeunghun Lee 3941751e8a6SLinus Torvalds if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) 3953cdf6fe9SSeunghun Lee return -EROFS; 3963cdf6fe9SSeunghun Lee 397399c109dSChengguang Xu if (*flags & SB_RDONLY && !sb_rdonly(sb)) { 39808f4c7c8SMiklos Szeredi upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 399c86243b0SVivek Goyal if (ovl_should_sync(ofs)) { 400399c109dSChengguang Xu down_read(&upper_sb->s_umount); 401399c109dSChengguang Xu ret = sync_filesystem(upper_sb); 402399c109dSChengguang Xu up_read(&upper_sb->s_umount); 403399c109dSChengguang Xu } 404c86243b0SVivek Goyal } 405399c109dSChengguang Xu 406399c109dSChengguang Xu return ret; 4073cdf6fe9SSeunghun Lee } 4083cdf6fe9SSeunghun Lee 409e9be9d5eSMiklos Szeredi static const struct super_operations ovl_super_operations = { 41013cf199dSAmir Goldstein .alloc_inode = ovl_alloc_inode, 4110b269dedSAl Viro .free_inode = ovl_free_inode, 41213cf199dSAmir Goldstein .destroy_inode = ovl_destroy_inode, 41313cf199dSAmir Goldstein .drop_inode = generic_delete_inode, 414e9be9d5eSMiklos Szeredi .put_super = ovl_put_super, 415e593b2bfSAmir Goldstein .sync_fs = ovl_sync_fs, 416cc259639SAndy Whitcroft .statfs = ovl_statfs, 417f45827e8SErez Zadok .show_options = ovl_show_options, 4183cdf6fe9SSeunghun Lee .remount_fs = ovl_remount, 419e9be9d5eSMiklos Szeredi }; 420e9be9d5eSMiklos Szeredi 421e9be9d5eSMiklos Szeredi enum { 422e9be9d5eSMiklos Szeredi OPT_LOWERDIR, 423e9be9d5eSMiklos Szeredi OPT_UPPERDIR, 424e9be9d5eSMiklos Szeredi OPT_WORKDIR, 4258d3095f4SMiklos Szeredi OPT_DEFAULT_PERMISSIONS, 426438c84c2SMiklos Szeredi OPT_REDIRECT_DIR, 42702bcd157SAmir Goldstein OPT_INDEX_ON, 42802bcd157SAmir Goldstein OPT_INDEX_OFF, 4295830fb6bSPavel Tikhomirov OPT_UUID_ON, 4305830fb6bSPavel Tikhomirov OPT_UUID_OFF, 431f168f109SAmir Goldstein OPT_NFS_EXPORT_ON, 4322d2f2d73SMiklos Szeredi OPT_USERXATTR, 433f168f109SAmir Goldstein OPT_NFS_EXPORT_OFF, 434795939a9SAmir Goldstein OPT_XINO_ON, 435795939a9SAmir Goldstein OPT_XINO_OFF, 436795939a9SAmir Goldstein OPT_XINO_AUTO, 437d5791044SVivek Goyal OPT_METACOPY_ON, 438d5791044SVivek Goyal OPT_METACOPY_OFF, 439c86243b0SVivek Goyal OPT_VOLATILE, 440e9be9d5eSMiklos Szeredi OPT_ERR, 441e9be9d5eSMiklos Szeredi }; 442e9be9d5eSMiklos Szeredi 443e9be9d5eSMiklos Szeredi static const match_table_t ovl_tokens = { 444e9be9d5eSMiklos Szeredi {OPT_LOWERDIR, "lowerdir=%s"}, 445e9be9d5eSMiklos Szeredi {OPT_UPPERDIR, "upperdir=%s"}, 446e9be9d5eSMiklos Szeredi {OPT_WORKDIR, "workdir=%s"}, 4478d3095f4SMiklos Szeredi {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, 448438c84c2SMiklos Szeredi {OPT_REDIRECT_DIR, "redirect_dir=%s"}, 44902bcd157SAmir Goldstein {OPT_INDEX_ON, "index=on"}, 45002bcd157SAmir Goldstein {OPT_INDEX_OFF, "index=off"}, 4512d2f2d73SMiklos Szeredi {OPT_USERXATTR, "userxattr"}, 4525830fb6bSPavel Tikhomirov {OPT_UUID_ON, "uuid=on"}, 4535830fb6bSPavel Tikhomirov {OPT_UUID_OFF, "uuid=off"}, 454f168f109SAmir Goldstein {OPT_NFS_EXPORT_ON, "nfs_export=on"}, 455f168f109SAmir Goldstein {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, 456795939a9SAmir Goldstein {OPT_XINO_ON, "xino=on"}, 457795939a9SAmir Goldstein {OPT_XINO_OFF, "xino=off"}, 458795939a9SAmir Goldstein {OPT_XINO_AUTO, "xino=auto"}, 459d5791044SVivek Goyal {OPT_METACOPY_ON, "metacopy=on"}, 460d5791044SVivek Goyal {OPT_METACOPY_OFF, "metacopy=off"}, 461c86243b0SVivek Goyal {OPT_VOLATILE, "volatile"}, 462e9be9d5eSMiklos Szeredi {OPT_ERR, NULL} 463e9be9d5eSMiklos Szeredi }; 464e9be9d5eSMiklos Szeredi 46591c77947SMiklos Szeredi static char *ovl_next_opt(char **s) 46691c77947SMiklos Szeredi { 46791c77947SMiklos Szeredi char *sbegin = *s; 46891c77947SMiklos Szeredi char *p; 46991c77947SMiklos Szeredi 47091c77947SMiklos Szeredi if (sbegin == NULL) 47191c77947SMiklos Szeredi return NULL; 47291c77947SMiklos Szeredi 47391c77947SMiklos Szeredi for (p = sbegin; *p; p++) { 47491c77947SMiklos Szeredi if (*p == '\\') { 47591c77947SMiklos Szeredi p++; 47691c77947SMiklos Szeredi if (!*p) 47791c77947SMiklos Szeredi break; 47891c77947SMiklos Szeredi } else if (*p == ',') { 47991c77947SMiklos Szeredi *p = '\0'; 48091c77947SMiklos Szeredi *s = p + 1; 48191c77947SMiklos Szeredi return sbegin; 48291c77947SMiklos Szeredi } 48391c77947SMiklos Szeredi } 48491c77947SMiklos Szeredi *s = NULL; 48591c77947SMiklos Szeredi return sbegin; 48691c77947SMiklos Szeredi } 48791c77947SMiklos Szeredi 488438c84c2SMiklos Szeredi static int ovl_parse_redirect_mode(struct ovl_config *config, const char *mode) 489438c84c2SMiklos Szeredi { 490438c84c2SMiklos Szeredi if (strcmp(mode, "on") == 0) { 491438c84c2SMiklos Szeredi config->redirect_dir = true; 492438c84c2SMiklos Szeredi /* 493438c84c2SMiklos Szeredi * Does not make sense to have redirect creation without 494438c84c2SMiklos Szeredi * redirect following. 495438c84c2SMiklos Szeredi */ 496438c84c2SMiklos Szeredi config->redirect_follow = true; 497438c84c2SMiklos Szeredi } else if (strcmp(mode, "follow") == 0) { 498438c84c2SMiklos Szeredi config->redirect_follow = true; 499438c84c2SMiklos Szeredi } else if (strcmp(mode, "off") == 0) { 500438c84c2SMiklos Szeredi if (ovl_redirect_always_follow) 501438c84c2SMiklos Szeredi config->redirect_follow = true; 502438c84c2SMiklos Szeredi } else if (strcmp(mode, "nofollow") != 0) { 5031bd0a3aeSlijiazi pr_err("bad mount option \"redirect_dir=%s\"\n", 504438c84c2SMiklos Szeredi mode); 505438c84c2SMiklos Szeredi return -EINVAL; 506438c84c2SMiklos Szeredi } 507438c84c2SMiklos Szeredi 508438c84c2SMiklos Szeredi return 0; 509438c84c2SMiklos Szeredi } 510438c84c2SMiklos Szeredi 511e9be9d5eSMiklos Szeredi static int ovl_parse_opt(char *opt, struct ovl_config *config) 512e9be9d5eSMiklos Szeredi { 513e9be9d5eSMiklos Szeredi char *p; 514d5791044SVivek Goyal int err; 515d47748e5SMiklos Szeredi bool metacopy_opt = false, redirect_opt = false; 516b0def88dSAmir Goldstein bool nfs_export_opt = false, index_opt = false; 517e9be9d5eSMiklos Szeredi 518438c84c2SMiklos Szeredi config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); 519438c84c2SMiklos Szeredi if (!config->redirect_mode) 520438c84c2SMiklos Szeredi return -ENOMEM; 521438c84c2SMiklos Szeredi 52291c77947SMiklos Szeredi while ((p = ovl_next_opt(&opt)) != NULL) { 523e9be9d5eSMiklos Szeredi int token; 524e9be9d5eSMiklos Szeredi substring_t args[MAX_OPT_ARGS]; 525e9be9d5eSMiklos Szeredi 526e9be9d5eSMiklos Szeredi if (!*p) 527e9be9d5eSMiklos Szeredi continue; 528e9be9d5eSMiklos Szeredi 529e9be9d5eSMiklos Szeredi token = match_token(p, ovl_tokens, args); 530e9be9d5eSMiklos Szeredi switch (token) { 531e9be9d5eSMiklos Szeredi case OPT_UPPERDIR: 532e9be9d5eSMiklos Szeredi kfree(config->upperdir); 533e9be9d5eSMiklos Szeredi config->upperdir = match_strdup(&args[0]); 534e9be9d5eSMiklos Szeredi if (!config->upperdir) 535e9be9d5eSMiklos Szeredi return -ENOMEM; 536e9be9d5eSMiklos Szeredi break; 537e9be9d5eSMiklos Szeredi 538e9be9d5eSMiklos Szeredi case OPT_LOWERDIR: 539e9be9d5eSMiklos Szeredi kfree(config->lowerdir); 540e9be9d5eSMiklos Szeredi config->lowerdir = match_strdup(&args[0]); 541e9be9d5eSMiklos Szeredi if (!config->lowerdir) 542e9be9d5eSMiklos Szeredi return -ENOMEM; 543e9be9d5eSMiklos Szeredi break; 544e9be9d5eSMiklos Szeredi 545e9be9d5eSMiklos Szeredi case OPT_WORKDIR: 546e9be9d5eSMiklos Szeredi kfree(config->workdir); 547e9be9d5eSMiklos Szeredi config->workdir = match_strdup(&args[0]); 548e9be9d5eSMiklos Szeredi if (!config->workdir) 549e9be9d5eSMiklos Szeredi return -ENOMEM; 550e9be9d5eSMiklos Szeredi break; 551e9be9d5eSMiklos Szeredi 5528d3095f4SMiklos Szeredi case OPT_DEFAULT_PERMISSIONS: 5538d3095f4SMiklos Szeredi config->default_permissions = true; 5548d3095f4SMiklos Szeredi break; 5558d3095f4SMiklos Szeredi 556438c84c2SMiklos Szeredi case OPT_REDIRECT_DIR: 557438c84c2SMiklos Szeredi kfree(config->redirect_mode); 558438c84c2SMiklos Szeredi config->redirect_mode = match_strdup(&args[0]); 559438c84c2SMiklos Szeredi if (!config->redirect_mode) 560438c84c2SMiklos Szeredi return -ENOMEM; 561d47748e5SMiklos Szeredi redirect_opt = true; 562a6c60655SMiklos Szeredi break; 563a6c60655SMiklos Szeredi 56402bcd157SAmir Goldstein case OPT_INDEX_ON: 56502bcd157SAmir Goldstein config->index = true; 566b0def88dSAmir Goldstein index_opt = true; 56702bcd157SAmir Goldstein break; 56802bcd157SAmir Goldstein 56902bcd157SAmir Goldstein case OPT_INDEX_OFF: 57002bcd157SAmir Goldstein config->index = false; 571b0def88dSAmir Goldstein index_opt = true; 57202bcd157SAmir Goldstein break; 57302bcd157SAmir Goldstein 5745830fb6bSPavel Tikhomirov case OPT_UUID_ON: 5755830fb6bSPavel Tikhomirov config->uuid = true; 5765830fb6bSPavel Tikhomirov break; 5775830fb6bSPavel Tikhomirov 5785830fb6bSPavel Tikhomirov case OPT_UUID_OFF: 5795830fb6bSPavel Tikhomirov config->uuid = false; 5805830fb6bSPavel Tikhomirov break; 5815830fb6bSPavel Tikhomirov 582f168f109SAmir Goldstein case OPT_NFS_EXPORT_ON: 583f168f109SAmir Goldstein config->nfs_export = true; 584b0def88dSAmir Goldstein nfs_export_opt = true; 585f168f109SAmir Goldstein break; 586f168f109SAmir Goldstein 587f168f109SAmir Goldstein case OPT_NFS_EXPORT_OFF: 588f168f109SAmir Goldstein config->nfs_export = false; 589b0def88dSAmir Goldstein nfs_export_opt = true; 590f168f109SAmir Goldstein break; 591f168f109SAmir Goldstein 592795939a9SAmir Goldstein case OPT_XINO_ON: 593795939a9SAmir Goldstein config->xino = OVL_XINO_ON; 594795939a9SAmir Goldstein break; 595795939a9SAmir Goldstein 596795939a9SAmir Goldstein case OPT_XINO_OFF: 597795939a9SAmir Goldstein config->xino = OVL_XINO_OFF; 598795939a9SAmir Goldstein break; 599795939a9SAmir Goldstein 600795939a9SAmir Goldstein case OPT_XINO_AUTO: 601795939a9SAmir Goldstein config->xino = OVL_XINO_AUTO; 602795939a9SAmir Goldstein break; 603795939a9SAmir Goldstein 604d5791044SVivek Goyal case OPT_METACOPY_ON: 605d5791044SVivek Goyal config->metacopy = true; 606d47748e5SMiklos Szeredi metacopy_opt = true; 607d5791044SVivek Goyal break; 608d5791044SVivek Goyal 609d5791044SVivek Goyal case OPT_METACOPY_OFF: 610d5791044SVivek Goyal config->metacopy = false; 611b0def88dSAmir Goldstein metacopy_opt = true; 612d5791044SVivek Goyal break; 613d5791044SVivek Goyal 614c86243b0SVivek Goyal case OPT_VOLATILE: 615c86243b0SVivek Goyal config->ovl_volatile = true; 616c86243b0SVivek Goyal break; 617c86243b0SVivek Goyal 6182d2f2d73SMiklos Szeredi case OPT_USERXATTR: 6192d2f2d73SMiklos Szeredi config->userxattr = true; 6202d2f2d73SMiklos Szeredi break; 6212d2f2d73SMiklos Szeredi 622e9be9d5eSMiklos Szeredi default: 6231bd0a3aeSlijiazi pr_err("unrecognized mount option \"%s\" or missing value\n", 6241bd0a3aeSlijiazi p); 625e9be9d5eSMiklos Szeredi return -EINVAL; 626e9be9d5eSMiklos Szeredi } 627e9be9d5eSMiklos Szeredi } 62871cbad7eShujianyang 629f0e1266eSAmir Goldstein /* Workdir/index are useless in non-upper mount */ 630f0e1266eSAmir Goldstein if (!config->upperdir) { 631f0e1266eSAmir Goldstein if (config->workdir) { 6321bd0a3aeSlijiazi pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", 63371cbad7eShujianyang config->workdir); 63471cbad7eShujianyang kfree(config->workdir); 63571cbad7eShujianyang config->workdir = NULL; 63671cbad7eShujianyang } 637f0e1266eSAmir Goldstein if (config->index && index_opt) { 638f0e1266eSAmir Goldstein pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); 639f0e1266eSAmir Goldstein index_opt = false; 640f0e1266eSAmir Goldstein } 641f0e1266eSAmir Goldstein config->index = false; 642f0e1266eSAmir Goldstein } 64371cbad7eShujianyang 644c86243b0SVivek Goyal if (!config->upperdir && config->ovl_volatile) { 645c86243b0SVivek Goyal pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); 646c86243b0SVivek Goyal config->ovl_volatile = false; 647c86243b0SVivek Goyal } 648c86243b0SVivek Goyal 649d5791044SVivek Goyal err = ovl_parse_redirect_mode(config, config->redirect_mode); 650d5791044SVivek Goyal if (err) 651d5791044SVivek Goyal return err; 652d5791044SVivek Goyal 653d47748e5SMiklos Szeredi /* 654d47748e5SMiklos Szeredi * This is to make the logic below simpler. It doesn't make any other 655d47748e5SMiklos Szeredi * difference, since config->redirect_dir is only used for upper. 656d47748e5SMiklos Szeredi */ 657d47748e5SMiklos Szeredi if (!config->upperdir && config->redirect_follow) 658d47748e5SMiklos Szeredi config->redirect_dir = true; 659d47748e5SMiklos Szeredi 660d47748e5SMiklos Szeredi /* Resolve metacopy -> redirect_dir dependency */ 661d47748e5SMiklos Szeredi if (config->metacopy && !config->redirect_dir) { 662d47748e5SMiklos Szeredi if (metacopy_opt && redirect_opt) { 6631bd0a3aeSlijiazi pr_err("conflicting options: metacopy=on,redirect_dir=%s\n", 664d47748e5SMiklos Szeredi config->redirect_mode); 665d47748e5SMiklos Szeredi return -EINVAL; 666d47748e5SMiklos Szeredi } 667d47748e5SMiklos Szeredi if (redirect_opt) { 668d47748e5SMiklos Szeredi /* 669d47748e5SMiklos Szeredi * There was an explicit redirect_dir=... that resulted 670d47748e5SMiklos Szeredi * in this conflict. 671d47748e5SMiklos Szeredi */ 6721bd0a3aeSlijiazi pr_info("disabling metacopy due to redirect_dir=%s\n", 673d47748e5SMiklos Szeredi config->redirect_mode); 674d5791044SVivek Goyal config->metacopy = false; 675d47748e5SMiklos Szeredi } else { 676d47748e5SMiklos Szeredi /* Automatically enable redirect otherwise. */ 677d47748e5SMiklos Szeredi config->redirect_follow = config->redirect_dir = true; 678d47748e5SMiklos Szeredi } 679d5791044SVivek Goyal } 680d5791044SVivek Goyal 681b0def88dSAmir Goldstein /* Resolve nfs_export -> index dependency */ 682b0def88dSAmir Goldstein if (config->nfs_export && !config->index) { 683f0e1266eSAmir Goldstein if (!config->upperdir && config->redirect_follow) { 684f0e1266eSAmir Goldstein pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); 685f0e1266eSAmir Goldstein config->nfs_export = false; 686f0e1266eSAmir Goldstein } else if (nfs_export_opt && index_opt) { 687b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,index=off\n"); 688b0def88dSAmir Goldstein return -EINVAL; 689f0e1266eSAmir Goldstein } else if (index_opt) { 690b0def88dSAmir Goldstein /* 691b0def88dSAmir Goldstein * There was an explicit index=off that resulted 692b0def88dSAmir Goldstein * in this conflict. 693b0def88dSAmir Goldstein */ 694b0def88dSAmir Goldstein pr_info("disabling nfs_export due to index=off\n"); 695b0def88dSAmir Goldstein config->nfs_export = false; 696b0def88dSAmir Goldstein } else { 697b0def88dSAmir Goldstein /* Automatically enable index otherwise. */ 698b0def88dSAmir Goldstein config->index = true; 699b0def88dSAmir Goldstein } 700b0def88dSAmir Goldstein } 701b0def88dSAmir Goldstein 702b0def88dSAmir Goldstein /* Resolve nfs_export -> !metacopy dependency */ 703b0def88dSAmir Goldstein if (config->nfs_export && config->metacopy) { 704b0def88dSAmir Goldstein if (nfs_export_opt && metacopy_opt) { 705b0def88dSAmir Goldstein pr_err("conflicting options: nfs_export=on,metacopy=on\n"); 706b0def88dSAmir Goldstein return -EINVAL; 707b0def88dSAmir Goldstein } 708b0def88dSAmir Goldstein if (metacopy_opt) { 709b0def88dSAmir Goldstein /* 710b0def88dSAmir Goldstein * There was an explicit metacopy=on that resulted 711b0def88dSAmir Goldstein * in this conflict. 712b0def88dSAmir Goldstein */ 713b0def88dSAmir Goldstein pr_info("disabling nfs_export due to metacopy=on\n"); 714b0def88dSAmir Goldstein config->nfs_export = false; 715b0def88dSAmir Goldstein } else { 716b0def88dSAmir Goldstein /* 717b0def88dSAmir Goldstein * There was an explicit nfs_export=on that resulted 718b0def88dSAmir Goldstein * in this conflict. 719b0def88dSAmir Goldstein */ 720b0def88dSAmir Goldstein pr_info("disabling metacopy due to nfs_export=on\n"); 721b0def88dSAmir Goldstein config->metacopy = false; 722b0def88dSAmir Goldstein } 723b0def88dSAmir Goldstein } 724b0def88dSAmir Goldstein 7252d2f2d73SMiklos Szeredi 7262d2f2d73SMiklos Szeredi /* Resolve userxattr -> !redirect && !metacopy dependency */ 7272d2f2d73SMiklos Szeredi if (config->userxattr) { 7282d2f2d73SMiklos Szeredi if (config->redirect_follow && redirect_opt) { 7292d2f2d73SMiklos Szeredi pr_err("conflicting options: userxattr,redirect_dir=%s\n", 7302d2f2d73SMiklos Szeredi config->redirect_mode); 7312d2f2d73SMiklos Szeredi return -EINVAL; 7322d2f2d73SMiklos Szeredi } 7332d2f2d73SMiklos Szeredi if (config->metacopy && metacopy_opt) { 7342d2f2d73SMiklos Szeredi pr_err("conflicting options: userxattr,metacopy=on\n"); 7352d2f2d73SMiklos Szeredi return -EINVAL; 7362d2f2d73SMiklos Szeredi } 7372d2f2d73SMiklos Szeredi /* 7382d2f2d73SMiklos Szeredi * Silently disable default setting of redirect and metacopy. 7392d2f2d73SMiklos Szeredi * This shall be the default in the future as well: these 7402d2f2d73SMiklos Szeredi * options must be explicitly enabled if used together with 7412d2f2d73SMiklos Szeredi * userxattr. 7422d2f2d73SMiklos Szeredi */ 7432d2f2d73SMiklos Szeredi config->redirect_dir = config->redirect_follow = false; 7442d2f2d73SMiklos Szeredi config->metacopy = false; 7452d2f2d73SMiklos Szeredi } 7462d2f2d73SMiklos Szeredi 747d5791044SVivek Goyal return 0; 748e9be9d5eSMiklos Szeredi } 749e9be9d5eSMiklos Szeredi 750e9be9d5eSMiklos Szeredi #define OVL_WORKDIR_NAME "work" 75102bcd157SAmir Goldstein #define OVL_INDEXDIR_NAME "index" 752e9be9d5eSMiklos Szeredi 753ad204488SMiklos Szeredi static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, 7546b8aa129SAmir Goldstein const char *name, bool persist) 755e9be9d5eSMiklos Szeredi { 756ad204488SMiklos Szeredi struct inode *dir = ofs->workbasedir->d_inode; 75708f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 758e9be9d5eSMiklos Szeredi struct dentry *work; 759e9be9d5eSMiklos Szeredi int err; 760e9be9d5eSMiklos Szeredi bool retried = false; 761e9be9d5eSMiklos Szeredi 7625955102cSAl Viro inode_lock_nested(dir, I_MUTEX_PARENT); 763e9be9d5eSMiklos Szeredi retry: 764ad204488SMiklos Szeredi work = lookup_one_len(name, ofs->workbasedir, strlen(name)); 765e9be9d5eSMiklos Szeredi 766e9be9d5eSMiklos Szeredi if (!IS_ERR(work)) { 767c11b9fddSMiklos Szeredi struct iattr attr = { 768c11b9fddSMiklos Szeredi .ia_valid = ATTR_MODE, 76932a3d848SAl Viro .ia_mode = S_IFDIR | 0, 770c11b9fddSMiklos Szeredi }; 771e9be9d5eSMiklos Szeredi 772e9be9d5eSMiklos Szeredi if (work->d_inode) { 773e9be9d5eSMiklos Szeredi err = -EEXIST; 774e9be9d5eSMiklos Szeredi if (retried) 775e9be9d5eSMiklos Szeredi goto out_dput; 776e9be9d5eSMiklos Szeredi 7776b8aa129SAmir Goldstein if (persist) 7786b8aa129SAmir Goldstein goto out_unlock; 7796b8aa129SAmir Goldstein 780e9be9d5eSMiklos Szeredi retried = true; 781235ce9edSAmir Goldstein err = ovl_workdir_cleanup(dir, mnt, work, 0); 782e9be9d5eSMiklos Szeredi dput(work); 783235ce9edSAmir Goldstein if (err == -EINVAL) { 784235ce9edSAmir Goldstein work = ERR_PTR(err); 785235ce9edSAmir Goldstein goto out_unlock; 786235ce9edSAmir Goldstein } 787e9be9d5eSMiklos Szeredi goto retry; 788e9be9d5eSMiklos Szeredi } 789e9be9d5eSMiklos Szeredi 7901f5573cfSMiklos Szeredi err = ovl_mkdir_real(dir, &work, attr.ia_mode); 7911f5573cfSMiklos Szeredi if (err) 7921f5573cfSMiklos Szeredi goto out_dput; 7931f5573cfSMiklos Szeredi 7941f5573cfSMiklos Szeredi /* Weird filesystem returning with hashed negative (kernfs)? */ 7951f5573cfSMiklos Szeredi err = -EINVAL; 7961f5573cfSMiklos Szeredi if (d_really_is_negative(work)) 7971f5573cfSMiklos Szeredi goto out_dput; 798c11b9fddSMiklos Szeredi 799cb348edbSMiklos Szeredi /* 800cb348edbSMiklos Szeredi * Try to remove POSIX ACL xattrs from workdir. We are good if: 801cb348edbSMiklos Szeredi * 802cb348edbSMiklos Szeredi * a) success (there was a POSIX ACL xattr and was removed) 803cb348edbSMiklos Szeredi * b) -ENODATA (there was no POSIX ACL xattr) 804cb348edbSMiklos Szeredi * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) 805cb348edbSMiklos Szeredi * 806cb348edbSMiklos Szeredi * There are various other error values that could effectively 807cb348edbSMiklos Szeredi * mean that the xattr doesn't exist (e.g. -ERANGE is returned 808cb348edbSMiklos Szeredi * if the xattr name is too long), but the set of filesystems 809cb348edbSMiklos Szeredi * allowed as upper are limited to "normal" ones, where checking 810cb348edbSMiklos Szeredi * for the above two errors is sufficient. 811cb348edbSMiklos Szeredi */ 812*c914c0e2SAmir Goldstein err = ovl_do_removexattr(ofs, work, 813c7c7a1a1STycho Andersen XATTR_NAME_POSIX_ACL_DEFAULT); 814e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 815c11b9fddSMiklos Szeredi goto out_dput; 816c11b9fddSMiklos Szeredi 817*c914c0e2SAmir Goldstein err = ovl_do_removexattr(ofs, work, 818c7c7a1a1STycho Andersen XATTR_NAME_POSIX_ACL_ACCESS); 819e1ff3dd1SMiklos Szeredi if (err && err != -ENODATA && err != -EOPNOTSUPP) 820c11b9fddSMiklos Szeredi goto out_dput; 821c11b9fddSMiklos Szeredi 822c11b9fddSMiklos Szeredi /* Clear any inherited mode bits */ 823c11b9fddSMiklos Szeredi inode_lock(work->d_inode); 8242f221d6fSChristian Brauner err = notify_change(&init_user_ns, work, &attr, NULL); 825c11b9fddSMiklos Szeredi inode_unlock(work->d_inode); 826c11b9fddSMiklos Szeredi if (err) 827c11b9fddSMiklos Szeredi goto out_dput; 8286b8aa129SAmir Goldstein } else { 8296b8aa129SAmir Goldstein err = PTR_ERR(work); 8306b8aa129SAmir Goldstein goto out_err; 831e9be9d5eSMiklos Szeredi } 832e9be9d5eSMiklos Szeredi out_unlock: 8336b8aa129SAmir Goldstein inode_unlock(dir); 834e9be9d5eSMiklos Szeredi return work; 835e9be9d5eSMiklos Szeredi 836e9be9d5eSMiklos Szeredi out_dput: 837e9be9d5eSMiklos Szeredi dput(work); 8386b8aa129SAmir Goldstein out_err: 8391bd0a3aeSlijiazi pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n", 840ad204488SMiklos Szeredi ofs->config.workdir, name, -err); 8416b8aa129SAmir Goldstein work = NULL; 842e9be9d5eSMiklos Szeredi goto out_unlock; 843e9be9d5eSMiklos Szeredi } 844e9be9d5eSMiklos Szeredi 84591c77947SMiklos Szeredi static void ovl_unescape(char *s) 84691c77947SMiklos Szeredi { 84791c77947SMiklos Szeredi char *d = s; 84891c77947SMiklos Szeredi 84991c77947SMiklos Szeredi for (;; s++, d++) { 85091c77947SMiklos Szeredi if (*s == '\\') 85191c77947SMiklos Szeredi s++; 85291c77947SMiklos Szeredi *d = *s; 85391c77947SMiklos Szeredi if (!*s) 85491c77947SMiklos Szeredi break; 85591c77947SMiklos Szeredi } 85691c77947SMiklos Szeredi } 85791c77947SMiklos Szeredi 858ab508822SMiklos Szeredi static int ovl_mount_dir_noesc(const char *name, struct path *path) 859ab508822SMiklos Szeredi { 860a78d9f0dSMiklos Szeredi int err = -EINVAL; 861ab508822SMiklos Szeredi 862a78d9f0dSMiklos Szeredi if (!*name) { 8631bd0a3aeSlijiazi pr_err("empty lowerdir\n"); 864a78d9f0dSMiklos Szeredi goto out; 865a78d9f0dSMiklos Szeredi } 866ab508822SMiklos Szeredi err = kern_path(name, LOOKUP_FOLLOW, path); 867ab508822SMiklos Szeredi if (err) { 8681bd0a3aeSlijiazi pr_err("failed to resolve '%s': %i\n", name, err); 869ab508822SMiklos Szeredi goto out; 870ab508822SMiklos Szeredi } 871ab508822SMiklos Szeredi err = -EINVAL; 8727c03b5d4SMiklos Szeredi if (ovl_dentry_weird(path->dentry)) { 8731bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported\n", name); 874ab508822SMiklos Szeredi goto out_put; 875ab508822SMiklos Szeredi } 876bb49e9e7SChristian Brauner if (is_idmapped_mnt(path->mnt)) { 877029a52adSChristian Brauner pr_err("idmapped layers are currently not supported\n"); 878029a52adSChristian Brauner goto out_put; 879029a52adSChristian Brauner } 8802b8c30e9SMiklos Szeredi if (!d_is_dir(path->dentry)) { 8811bd0a3aeSlijiazi pr_err("'%s' not a directory\n", name); 882ab508822SMiklos Szeredi goto out_put; 883ab508822SMiklos Szeredi } 884ab508822SMiklos Szeredi return 0; 885ab508822SMiklos Szeredi 886ab508822SMiklos Szeredi out_put: 8878aafcb59SMiklos Szeredi path_put_init(path); 888ab508822SMiklos Szeredi out: 889ab508822SMiklos Szeredi return err; 890ab508822SMiklos Szeredi } 891ab508822SMiklos Szeredi 892ab508822SMiklos Szeredi static int ovl_mount_dir(const char *name, struct path *path) 893ab508822SMiklos Szeredi { 894ab508822SMiklos Szeredi int err = -ENOMEM; 895ab508822SMiklos Szeredi char *tmp = kstrdup(name, GFP_KERNEL); 896ab508822SMiklos Szeredi 897ab508822SMiklos Szeredi if (tmp) { 898ab508822SMiklos Szeredi ovl_unescape(tmp); 899ab508822SMiklos Szeredi err = ovl_mount_dir_noesc(tmp, path); 9007c03b5d4SMiklos Szeredi 901bccece1eSMiklos Szeredi if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { 9021bd0a3aeSlijiazi pr_err("filesystem on '%s' not supported as upperdir\n", 9037c03b5d4SMiklos Szeredi tmp); 9048aafcb59SMiklos Szeredi path_put_init(path); 9057c03b5d4SMiklos Szeredi err = -EINVAL; 9067c03b5d4SMiklos Szeredi } 907ab508822SMiklos Szeredi kfree(tmp); 908ab508822SMiklos Szeredi } 909ab508822SMiklos Szeredi return err; 910ab508822SMiklos Szeredi } 911ab508822SMiklos Szeredi 9126b2d5fe4SMiklos Szeredi static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, 9136b2d5fe4SMiklos Szeredi const char *name) 9146b2d5fe4SMiklos Szeredi { 9156b2d5fe4SMiklos Szeredi struct kstatfs statfs; 9166b2d5fe4SMiklos Szeredi int err = vfs_statfs(path, &statfs); 9176b2d5fe4SMiklos Szeredi 9186b2d5fe4SMiklos Szeredi if (err) 9191bd0a3aeSlijiazi pr_err("statfs failed on '%s'\n", name); 9206b2d5fe4SMiklos Szeredi else 9216b2d5fe4SMiklos Szeredi ofs->namelen = max(ofs->namelen, statfs.f_namelen); 9226b2d5fe4SMiklos Szeredi 9236b2d5fe4SMiklos Szeredi return err; 9246b2d5fe4SMiklos Szeredi } 9256b2d5fe4SMiklos Szeredi 9266b2d5fe4SMiklos Szeredi static int ovl_lower_dir(const char *name, struct path *path, 927f4288844SMiklos Szeredi struct ovl_fs *ofs, int *stack_depth) 928ab508822SMiklos Szeredi { 929e487d889SAmir Goldstein int fh_type; 930ab508822SMiklos Szeredi int err; 931ab508822SMiklos Szeredi 932a78d9f0dSMiklos Szeredi err = ovl_mount_dir_noesc(name, path); 933ab508822SMiklos Szeredi if (err) 934b8e42a65SMiklos Szeredi return err; 935ab508822SMiklos Szeredi 9366b2d5fe4SMiklos Szeredi err = ovl_check_namelen(path, ofs, name); 9376b2d5fe4SMiklos Szeredi if (err) 938b8e42a65SMiklos Szeredi return err; 9396b2d5fe4SMiklos Szeredi 940ab508822SMiklos Szeredi *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); 941ab508822SMiklos Szeredi 94202bcd157SAmir Goldstein /* 943f168f109SAmir Goldstein * The inodes index feature and NFS export need to encode and decode 944f168f109SAmir Goldstein * file handles, so they require that all layers support them. 94502bcd157SAmir Goldstein */ 946e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(path->dentry->d_sb); 947f168f109SAmir Goldstein if ((ofs->config.nfs_export || 948e487d889SAmir Goldstein (ofs->config.index && ofs->config.upperdir)) && !fh_type) { 94902bcd157SAmir Goldstein ofs->config.index = false; 950f168f109SAmir Goldstein ofs->config.nfs_export = false; 9511bd0a3aeSlijiazi pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", 952f168f109SAmir Goldstein name); 95302bcd157SAmir Goldstein } 954b0e0f697SAmir Goldstein /* 955b0e0f697SAmir Goldstein * Decoding origin file handle is required for persistent st_ino. 956b0e0f697SAmir Goldstein * Without persistent st_ino, xino=auto falls back to xino=off. 957b0e0f697SAmir Goldstein */ 958b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO && 959b0e0f697SAmir Goldstein ofs->config.upperdir && !fh_type) { 960b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 961b0e0f697SAmir Goldstein pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", 962b0e0f697SAmir Goldstein name); 963b0e0f697SAmir Goldstein } 96402bcd157SAmir Goldstein 965e487d889SAmir Goldstein /* Check if lower fs has 32bit inode numbers */ 966e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 9670f831ec8SAmir Goldstein ofs->xino_mode = -1; 968e487d889SAmir Goldstein 969ab508822SMiklos Szeredi return 0; 970ab508822SMiklos Szeredi } 971ab508822SMiklos Szeredi 972e9be9d5eSMiklos Szeredi /* Workdir should not be subdir of upperdir and vice versa */ 973e9be9d5eSMiklos Szeredi static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) 974e9be9d5eSMiklos Szeredi { 975e9be9d5eSMiklos Szeredi bool ok = false; 976e9be9d5eSMiklos Szeredi 977e9be9d5eSMiklos Szeredi if (workdir != upperdir) { 978e9be9d5eSMiklos Szeredi ok = (lock_rename(workdir, upperdir) == NULL); 979e9be9d5eSMiklos Szeredi unlock_rename(workdir, upperdir); 980e9be9d5eSMiklos Szeredi } 981e9be9d5eSMiklos Szeredi return ok; 982e9be9d5eSMiklos Szeredi } 983e9be9d5eSMiklos Szeredi 984a78d9f0dSMiklos Szeredi static unsigned int ovl_split_lowerdirs(char *str) 985a78d9f0dSMiklos Szeredi { 986a78d9f0dSMiklos Szeredi unsigned int ctr = 1; 987a78d9f0dSMiklos Szeredi char *s, *d; 988a78d9f0dSMiklos Szeredi 989a78d9f0dSMiklos Szeredi for (s = d = str;; s++, d++) { 990a78d9f0dSMiklos Szeredi if (*s == '\\') { 991a78d9f0dSMiklos Szeredi s++; 992a78d9f0dSMiklos Szeredi } else if (*s == ':') { 993a78d9f0dSMiklos Szeredi *d = '\0'; 994a78d9f0dSMiklos Szeredi ctr++; 995a78d9f0dSMiklos Szeredi continue; 996a78d9f0dSMiklos Szeredi } 997a78d9f0dSMiklos Szeredi *d = *s; 998a78d9f0dSMiklos Szeredi if (!*s) 999a78d9f0dSMiklos Szeredi break; 1000a78d9f0dSMiklos Szeredi } 1001a78d9f0dSMiklos Szeredi return ctr; 1002a78d9f0dSMiklos Szeredi } 1003a78d9f0dSMiklos Szeredi 10040c97be22SAndreas Gruenbacher static int __maybe_unused 10050eb45fc3SAndreas Gruenbacher ovl_posix_acl_xattr_get(const struct xattr_handler *handler, 10060eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10070eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10080eb45fc3SAndreas Gruenbacher { 10091d88f183SMiklos Szeredi return ovl_xattr_get(dentry, inode, handler->name, buffer, size); 10100eb45fc3SAndreas Gruenbacher } 10110eb45fc3SAndreas Gruenbacher 10120eb45fc3SAndreas Gruenbacher static int __maybe_unused 10130c97be22SAndreas Gruenbacher ovl_posix_acl_xattr_set(const struct xattr_handler *handler, 1014e65ce2a5SChristian Brauner struct user_namespace *mnt_userns, 1015d837a49bSMiklos Szeredi struct dentry *dentry, struct inode *inode, 1016d837a49bSMiklos Szeredi const char *name, const void *value, 1017d837a49bSMiklos Szeredi size_t size, int flags) 1018d837a49bSMiklos Szeredi { 1019d837a49bSMiklos Szeredi struct dentry *workdir = ovl_workdir(dentry); 102009d8b586SMiklos Szeredi struct inode *realinode = ovl_inode_real(inode); 1021d837a49bSMiklos Szeredi struct posix_acl *acl = NULL; 1022d837a49bSMiklos Szeredi int err; 1023d837a49bSMiklos Szeredi 1024d837a49bSMiklos Szeredi /* Check that everything is OK before copy-up */ 1025d837a49bSMiklos Szeredi if (value) { 1026d837a49bSMiklos Szeredi acl = posix_acl_from_xattr(&init_user_ns, value, size); 1027d837a49bSMiklos Szeredi if (IS_ERR(acl)) 1028d837a49bSMiklos Szeredi return PTR_ERR(acl); 1029d837a49bSMiklos Szeredi } 1030d837a49bSMiklos Szeredi err = -EOPNOTSUPP; 1031d837a49bSMiklos Szeredi if (!IS_POSIXACL(d_inode(workdir))) 1032d837a49bSMiklos Szeredi goto out_acl_release; 1033d837a49bSMiklos Szeredi if (!realinode->i_op->set_acl) 1034d837a49bSMiklos Szeredi goto out_acl_release; 1035d837a49bSMiklos Szeredi if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { 1036d837a49bSMiklos Szeredi err = acl ? -EACCES : 0; 1037d837a49bSMiklos Szeredi goto out_acl_release; 1038d837a49bSMiklos Szeredi } 1039d837a49bSMiklos Szeredi err = -EPERM; 104021cb47beSChristian Brauner if (!inode_owner_or_capable(&init_user_ns, inode)) 1041d837a49bSMiklos Szeredi goto out_acl_release; 1042d837a49bSMiklos Szeredi 1043d837a49bSMiklos Szeredi posix_acl_release(acl); 1044d837a49bSMiklos Szeredi 1045fd3220d3SMiklos Szeredi /* 1046fd3220d3SMiklos Szeredi * Check if sgid bit needs to be cleared (actual setacl operation will 1047fd3220d3SMiklos Szeredi * be done with mounter's capabilities and so that won't do it for us). 1048fd3220d3SMiklos Szeredi */ 1049fd3220d3SMiklos Szeredi if (unlikely(inode->i_mode & S_ISGID) && 1050fd3220d3SMiklos Szeredi handler->flags == ACL_TYPE_ACCESS && 1051fd3220d3SMiklos Szeredi !in_group_p(inode->i_gid) && 10520558c1bfSChristian Brauner !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) { 1053fd3220d3SMiklos Szeredi struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; 1054fd3220d3SMiklos Szeredi 1055549c7297SChristian Brauner err = ovl_setattr(&init_user_ns, dentry, &iattr); 1056fd3220d3SMiklos Szeredi if (err) 1057fd3220d3SMiklos Szeredi return err; 1058fd3220d3SMiklos Szeredi } 1059fd3220d3SMiklos Szeredi 10601d88f183SMiklos Szeredi err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); 1061ce31513aSMiklos Szeredi return err; 1062d837a49bSMiklos Szeredi 1063d837a49bSMiklos Szeredi out_acl_release: 1064d837a49bSMiklos Szeredi posix_acl_release(acl); 1065d837a49bSMiklos Szeredi return err; 1066d837a49bSMiklos Szeredi } 1067d837a49bSMiklos Szeredi 10680eb45fc3SAndreas Gruenbacher static int ovl_own_xattr_get(const struct xattr_handler *handler, 10690eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10700eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10710eb45fc3SAndreas Gruenbacher { 107248fab5d7SAmir Goldstein return -EOPNOTSUPP; 10730eb45fc3SAndreas Gruenbacher } 10740eb45fc3SAndreas Gruenbacher 1075d837a49bSMiklos Szeredi static int ovl_own_xattr_set(const struct xattr_handler *handler, 1076e65ce2a5SChristian Brauner struct user_namespace *mnt_userns, 1077d837a49bSMiklos Szeredi struct dentry *dentry, struct inode *inode, 1078d837a49bSMiklos Szeredi const char *name, const void *value, 1079d837a49bSMiklos Szeredi size_t size, int flags) 1080d837a49bSMiklos Szeredi { 108148fab5d7SAmir Goldstein return -EOPNOTSUPP; 1082d837a49bSMiklos Szeredi } 1083d837a49bSMiklos Szeredi 10840eb45fc3SAndreas Gruenbacher static int ovl_other_xattr_get(const struct xattr_handler *handler, 10850eb45fc3SAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10860eb45fc3SAndreas Gruenbacher const char *name, void *buffer, size_t size) 10870eb45fc3SAndreas Gruenbacher { 10881d88f183SMiklos Szeredi return ovl_xattr_get(dentry, inode, name, buffer, size); 10890eb45fc3SAndreas Gruenbacher } 10900eb45fc3SAndreas Gruenbacher 10910e585cccSAndreas Gruenbacher static int ovl_other_xattr_set(const struct xattr_handler *handler, 1092e65ce2a5SChristian Brauner struct user_namespace *mnt_userns, 10930e585cccSAndreas Gruenbacher struct dentry *dentry, struct inode *inode, 10940e585cccSAndreas Gruenbacher const char *name, const void *value, 10950e585cccSAndreas Gruenbacher size_t size, int flags) 10960e585cccSAndreas Gruenbacher { 10971d88f183SMiklos Szeredi return ovl_xattr_set(dentry, inode, name, value, size, flags); 10980e585cccSAndreas Gruenbacher } 10990e585cccSAndreas Gruenbacher 11000c97be22SAndreas Gruenbacher static const struct xattr_handler __maybe_unused 11010c97be22SAndreas Gruenbacher ovl_posix_acl_access_xattr_handler = { 1102d837a49bSMiklos Szeredi .name = XATTR_NAME_POSIX_ACL_ACCESS, 1103d837a49bSMiklos Szeredi .flags = ACL_TYPE_ACCESS, 11040eb45fc3SAndreas Gruenbacher .get = ovl_posix_acl_xattr_get, 1105d837a49bSMiklos Szeredi .set = ovl_posix_acl_xattr_set, 1106d837a49bSMiklos Szeredi }; 1107d837a49bSMiklos Szeredi 11080c97be22SAndreas Gruenbacher static const struct xattr_handler __maybe_unused 11090c97be22SAndreas Gruenbacher ovl_posix_acl_default_xattr_handler = { 1110d837a49bSMiklos Szeredi .name = XATTR_NAME_POSIX_ACL_DEFAULT, 1111d837a49bSMiklos Szeredi .flags = ACL_TYPE_DEFAULT, 11120eb45fc3SAndreas Gruenbacher .get = ovl_posix_acl_xattr_get, 1113d837a49bSMiklos Szeredi .set = ovl_posix_acl_xattr_set, 1114d837a49bSMiklos Szeredi }; 1115d837a49bSMiklos Szeredi 11162d2f2d73SMiklos Szeredi static const struct xattr_handler ovl_own_trusted_xattr_handler = { 11172d2f2d73SMiklos Szeredi .prefix = OVL_XATTR_TRUSTED_PREFIX, 11182d2f2d73SMiklos Szeredi .get = ovl_own_xattr_get, 11192d2f2d73SMiklos Szeredi .set = ovl_own_xattr_set, 11202d2f2d73SMiklos Szeredi }; 11212d2f2d73SMiklos Szeredi 11222d2f2d73SMiklos Szeredi static const struct xattr_handler ovl_own_user_xattr_handler = { 11232d2f2d73SMiklos Szeredi .prefix = OVL_XATTR_USER_PREFIX, 11240eb45fc3SAndreas Gruenbacher .get = ovl_own_xattr_get, 1125d837a49bSMiklos Szeredi .set = ovl_own_xattr_set, 1126d837a49bSMiklos Szeredi }; 1127d837a49bSMiklos Szeredi 1128d837a49bSMiklos Szeredi static const struct xattr_handler ovl_other_xattr_handler = { 1129d837a49bSMiklos Szeredi .prefix = "", /* catch all */ 11300eb45fc3SAndreas Gruenbacher .get = ovl_other_xattr_get, 1131d837a49bSMiklos Szeredi .set = ovl_other_xattr_set, 1132d837a49bSMiklos Szeredi }; 1133d837a49bSMiklos Szeredi 11342d2f2d73SMiklos Szeredi static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { 11350c97be22SAndreas Gruenbacher #ifdef CONFIG_FS_POSIX_ACL 1136d837a49bSMiklos Szeredi &ovl_posix_acl_access_xattr_handler, 1137d837a49bSMiklos Szeredi &ovl_posix_acl_default_xattr_handler, 11380c97be22SAndreas Gruenbacher #endif 11392d2f2d73SMiklos Szeredi &ovl_own_trusted_xattr_handler, 11402d2f2d73SMiklos Szeredi &ovl_other_xattr_handler, 11412d2f2d73SMiklos Szeredi NULL 11422d2f2d73SMiklos Szeredi }; 11432d2f2d73SMiklos Szeredi 11442d2f2d73SMiklos Szeredi static const struct xattr_handler *ovl_user_xattr_handlers[] = { 11452d2f2d73SMiklos Szeredi #ifdef CONFIG_FS_POSIX_ACL 11462d2f2d73SMiklos Szeredi &ovl_posix_acl_access_xattr_handler, 11472d2f2d73SMiklos Szeredi &ovl_posix_acl_default_xattr_handler, 11482d2f2d73SMiklos Szeredi #endif 11492d2f2d73SMiklos Szeredi &ovl_own_user_xattr_handler, 1150d837a49bSMiklos Szeredi &ovl_other_xattr_handler, 1151d837a49bSMiklos Szeredi NULL 1152d837a49bSMiklos Szeredi }; 1153d837a49bSMiklos Szeredi 1154146d62e5SAmir Goldstein static int ovl_setup_trap(struct super_block *sb, struct dentry *dir, 1155146d62e5SAmir Goldstein struct inode **ptrap, const char *name) 1156146d62e5SAmir Goldstein { 1157146d62e5SAmir Goldstein struct inode *trap; 1158146d62e5SAmir Goldstein int err; 1159146d62e5SAmir Goldstein 1160146d62e5SAmir Goldstein trap = ovl_get_trap_inode(sb, dir); 11611dac6f5bSArnd Bergmann err = PTR_ERR_OR_ZERO(trap); 11621dac6f5bSArnd Bergmann if (err) { 1163146d62e5SAmir Goldstein if (err == -ELOOP) 11641bd0a3aeSlijiazi pr_err("conflicting %s path\n", name); 1165146d62e5SAmir Goldstein return err; 1166146d62e5SAmir Goldstein } 1167146d62e5SAmir Goldstein 1168146d62e5SAmir Goldstein *ptrap = trap; 1169146d62e5SAmir Goldstein return 0; 1170146d62e5SAmir Goldstein } 1171146d62e5SAmir Goldstein 11720be0bfd2SAmir Goldstein /* 11730be0bfd2SAmir Goldstein * Determine how we treat concurrent use of upperdir/workdir based on the 11740be0bfd2SAmir Goldstein * index feature. This is papering over mount leaks of container runtimes, 11750be0bfd2SAmir Goldstein * for example, an old overlay mount is leaked and now its upperdir is 11760be0bfd2SAmir Goldstein * attempted to be used as a lower layer in a new overlay mount. 11770be0bfd2SAmir Goldstein */ 11780be0bfd2SAmir Goldstein static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) 11790be0bfd2SAmir Goldstein { 11800be0bfd2SAmir Goldstein if (ofs->config.index) { 11811bd0a3aeSlijiazi pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n", 11820be0bfd2SAmir Goldstein name); 11830be0bfd2SAmir Goldstein return -EBUSY; 11840be0bfd2SAmir Goldstein } else { 11851bd0a3aeSlijiazi pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n", 11860be0bfd2SAmir Goldstein name); 11870be0bfd2SAmir Goldstein return 0; 11880be0bfd2SAmir Goldstein } 11890be0bfd2SAmir Goldstein } 11900be0bfd2SAmir Goldstein 1191146d62e5SAmir Goldstein static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, 1192b8e42a65SMiklos Szeredi struct ovl_layer *upper_layer, struct path *upperpath) 11936ee8acf0SMiklos Szeredi { 11945064975eSMiklos Szeredi struct vfsmount *upper_mnt; 11956ee8acf0SMiklos Szeredi int err; 11966ee8acf0SMiklos Szeredi 1197ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.upperdir, upperpath); 11986ee8acf0SMiklos Szeredi if (err) 11996ee8acf0SMiklos Szeredi goto out; 12006ee8acf0SMiklos Szeredi 1201e21a6c57SAmir Goldstein /* Upperdir path should not be r/o */ 1202e21a6c57SAmir Goldstein if (__mnt_is_readonly(upperpath->mnt)) { 12031bd0a3aeSlijiazi pr_err("upper fs is r/o, try multi-lower layers mount\n"); 12046ee8acf0SMiklos Szeredi err = -EINVAL; 12056ee8acf0SMiklos Szeredi goto out; 12066ee8acf0SMiklos Szeredi } 12076ee8acf0SMiklos Szeredi 1208ad204488SMiklos Szeredi err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir); 12096ee8acf0SMiklos Szeredi if (err) 12106ee8acf0SMiklos Szeredi goto out; 12116ee8acf0SMiklos Szeredi 1212b8e42a65SMiklos Szeredi err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, 1213146d62e5SAmir Goldstein "upperdir"); 1214146d62e5SAmir Goldstein if (err) 1215146d62e5SAmir Goldstein goto out; 1216146d62e5SAmir Goldstein 12175064975eSMiklos Szeredi upper_mnt = clone_private_mount(upperpath); 12185064975eSMiklos Szeredi err = PTR_ERR(upper_mnt); 12195064975eSMiklos Szeredi if (IS_ERR(upper_mnt)) { 12201bd0a3aeSlijiazi pr_err("failed to clone upperpath\n"); 12215064975eSMiklos Szeredi goto out; 12225064975eSMiklos Szeredi } 12235064975eSMiklos Szeredi 12245064975eSMiklos Szeredi /* Don't inherit atime flags */ 12255064975eSMiklos Szeredi upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); 1226b8e42a65SMiklos Szeredi upper_layer->mnt = upper_mnt; 1227b8e42a65SMiklos Szeredi upper_layer->idx = 0; 1228b8e42a65SMiklos Szeredi upper_layer->fsid = 0; 12298c25741aSMiklos Szeredi 1230654255faSJeffle Xu /* 1231654255faSJeffle Xu * Inherit SB_NOSEC flag from upperdir. 1232654255faSJeffle Xu * 1233654255faSJeffle Xu * This optimization changes behavior when a security related attribute 1234654255faSJeffle Xu * (suid/sgid/security.*) is changed on an underlying layer. This is 1235654255faSJeffle Xu * okay because we don't yet have guarantees in that case, but it will 1236654255faSJeffle Xu * need careful treatment once we want to honour changes to underlying 1237654255faSJeffle Xu * filesystems. 1238654255faSJeffle Xu */ 1239654255faSJeffle Xu if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) 1240654255faSJeffle Xu sb->s_flags |= SB_NOSEC; 1241654255faSJeffle Xu 124208f4c7c8SMiklos Szeredi if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { 12438c25741aSMiklos Szeredi ofs->upperdir_locked = true; 12448c25741aSMiklos Szeredi } else { 12450be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "upperdir"); 12460be0bfd2SAmir Goldstein if (err) 12470be0bfd2SAmir Goldstein goto out; 12488c25741aSMiklos Szeredi } 12498c25741aSMiklos Szeredi 12506ee8acf0SMiklos Szeredi err = 0; 12516ee8acf0SMiklos Szeredi out: 12526ee8acf0SMiklos Szeredi return err; 12536ee8acf0SMiklos Szeredi } 12546ee8acf0SMiklos Szeredi 1255cad218abSAmir Goldstein /* 1256cad218abSAmir Goldstein * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and 1257cad218abSAmir Goldstein * negative values if error is encountered. 1258cad218abSAmir Goldstein */ 1259cad218abSAmir Goldstein static int ovl_check_rename_whiteout(struct dentry *workdir) 1260cad218abSAmir Goldstein { 1261cad218abSAmir Goldstein struct inode *dir = d_inode(workdir); 1262cad218abSAmir Goldstein struct dentry *temp; 1263cad218abSAmir Goldstein struct dentry *dest; 1264cad218abSAmir Goldstein struct dentry *whiteout; 1265cad218abSAmir Goldstein struct name_snapshot name; 1266cad218abSAmir Goldstein int err; 1267cad218abSAmir Goldstein 1268cad218abSAmir Goldstein inode_lock_nested(dir, I_MUTEX_PARENT); 1269cad218abSAmir Goldstein 1270cad218abSAmir Goldstein temp = ovl_create_temp(workdir, OVL_CATTR(S_IFREG | 0)); 1271cad218abSAmir Goldstein err = PTR_ERR(temp); 1272cad218abSAmir Goldstein if (IS_ERR(temp)) 1273cad218abSAmir Goldstein goto out_unlock; 1274cad218abSAmir Goldstein 1275cad218abSAmir Goldstein dest = ovl_lookup_temp(workdir); 1276cad218abSAmir Goldstein err = PTR_ERR(dest); 1277cad218abSAmir Goldstein if (IS_ERR(dest)) { 1278cad218abSAmir Goldstein dput(temp); 1279cad218abSAmir Goldstein goto out_unlock; 1280cad218abSAmir Goldstein } 1281cad218abSAmir Goldstein 1282cad218abSAmir Goldstein /* Name is inline and stable - using snapshot as a copy helper */ 1283cad218abSAmir Goldstein take_dentry_name_snapshot(&name, temp); 1284cad218abSAmir Goldstein err = ovl_do_rename(dir, temp, dir, dest, RENAME_WHITEOUT); 1285cad218abSAmir Goldstein if (err) { 1286cad218abSAmir Goldstein if (err == -EINVAL) 1287cad218abSAmir Goldstein err = 0; 1288cad218abSAmir Goldstein goto cleanup_temp; 1289cad218abSAmir Goldstein } 1290cad218abSAmir Goldstein 1291cad218abSAmir Goldstein whiteout = lookup_one_len(name.name.name, workdir, name.name.len); 1292cad218abSAmir Goldstein err = PTR_ERR(whiteout); 1293cad218abSAmir Goldstein if (IS_ERR(whiteout)) 1294cad218abSAmir Goldstein goto cleanup_temp; 1295cad218abSAmir Goldstein 1296cad218abSAmir Goldstein err = ovl_is_whiteout(whiteout); 1297cad218abSAmir Goldstein 1298cad218abSAmir Goldstein /* Best effort cleanup of whiteout and temp file */ 1299cad218abSAmir Goldstein if (err) 1300cad218abSAmir Goldstein ovl_cleanup(dir, whiteout); 1301cad218abSAmir Goldstein dput(whiteout); 1302cad218abSAmir Goldstein 1303cad218abSAmir Goldstein cleanup_temp: 1304cad218abSAmir Goldstein ovl_cleanup(dir, temp); 1305cad218abSAmir Goldstein release_dentry_name_snapshot(&name); 1306cad218abSAmir Goldstein dput(temp); 1307cad218abSAmir Goldstein dput(dest); 1308cad218abSAmir Goldstein 1309cad218abSAmir Goldstein out_unlock: 1310cad218abSAmir Goldstein inode_unlock(dir); 1311cad218abSAmir Goldstein 1312cad218abSAmir Goldstein return err; 1313cad218abSAmir Goldstein } 1314cad218abSAmir Goldstein 1315c86243b0SVivek Goyal static struct dentry *ovl_lookup_or_create(struct dentry *parent, 1316c86243b0SVivek Goyal const char *name, umode_t mode) 1317c86243b0SVivek Goyal { 1318c86243b0SVivek Goyal size_t len = strlen(name); 1319c86243b0SVivek Goyal struct dentry *child; 1320c86243b0SVivek Goyal 1321c86243b0SVivek Goyal inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); 1322c86243b0SVivek Goyal child = lookup_one_len(name, parent, len); 1323c86243b0SVivek Goyal if (!IS_ERR(child) && !child->d_inode) 1324c86243b0SVivek Goyal child = ovl_create_real(parent->d_inode, child, 1325c86243b0SVivek Goyal OVL_CATTR(mode)); 1326c86243b0SVivek Goyal inode_unlock(parent->d_inode); 1327c86243b0SVivek Goyal dput(parent); 1328c86243b0SVivek Goyal 1329c86243b0SVivek Goyal return child; 1330c86243b0SVivek Goyal } 1331c86243b0SVivek Goyal 1332c86243b0SVivek Goyal /* 1333c86243b0SVivek Goyal * Creates $workdir/work/incompat/volatile/dirty file if it is not already 1334c86243b0SVivek Goyal * present. 1335c86243b0SVivek Goyal */ 1336c86243b0SVivek Goyal static int ovl_create_volatile_dirty(struct ovl_fs *ofs) 1337c86243b0SVivek Goyal { 1338c86243b0SVivek Goyal unsigned int ctr; 1339c86243b0SVivek Goyal struct dentry *d = dget(ofs->workbasedir); 1340c86243b0SVivek Goyal static const char *const volatile_path[] = { 1341c86243b0SVivek Goyal OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" 1342c86243b0SVivek Goyal }; 1343c86243b0SVivek Goyal const char *const *name = volatile_path; 1344c86243b0SVivek Goyal 1345c86243b0SVivek Goyal for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { 1346c86243b0SVivek Goyal d = ovl_lookup_or_create(d, *name, ctr > 1 ? S_IFDIR : S_IFREG); 1347c86243b0SVivek Goyal if (IS_ERR(d)) 1348c86243b0SVivek Goyal return PTR_ERR(d); 1349c86243b0SVivek Goyal } 1350c86243b0SVivek Goyal dput(d); 1351c86243b0SVivek Goyal return 0; 1352c86243b0SVivek Goyal } 1353c86243b0SVivek Goyal 1354146d62e5SAmir Goldstein static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, 1355146d62e5SAmir Goldstein struct path *workpath) 13568ed61dc3SMiklos Szeredi { 135708f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 1358235ce9edSAmir Goldstein struct dentry *temp, *workdir; 1359d80172c2SAmir Goldstein bool rename_whiteout; 1360d80172c2SAmir Goldstein bool d_type; 1361e487d889SAmir Goldstein int fh_type; 13628ed61dc3SMiklos Szeredi int err; 13638ed61dc3SMiklos Szeredi 13642ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 13652ba9d57eSAmir Goldstein if (err) 13662ba9d57eSAmir Goldstein return err; 13672ba9d57eSAmir Goldstein 1368235ce9edSAmir Goldstein workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); 1369235ce9edSAmir Goldstein err = PTR_ERR(workdir); 1370235ce9edSAmir Goldstein if (IS_ERR_OR_NULL(workdir)) 13712ba9d57eSAmir Goldstein goto out; 13728ed61dc3SMiklos Szeredi 1373235ce9edSAmir Goldstein ofs->workdir = workdir; 1374235ce9edSAmir Goldstein 1375146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); 1376146d62e5SAmir Goldstein if (err) 1377146d62e5SAmir Goldstein goto out; 1378146d62e5SAmir Goldstein 13798ed61dc3SMiklos Szeredi /* 13808ed61dc3SMiklos Szeredi * Upper should support d_type, else whiteouts are visible. Given 13818ed61dc3SMiklos Szeredi * workdir and upper are on same fs, we can do iterate_dir() on 13828ed61dc3SMiklos Szeredi * workdir. This check requires successful creation of workdir in 13838ed61dc3SMiklos Szeredi * previous step. 13848ed61dc3SMiklos Szeredi */ 13858ed61dc3SMiklos Szeredi err = ovl_check_d_type_supported(workpath); 13868ed61dc3SMiklos Szeredi if (err < 0) 13872ba9d57eSAmir Goldstein goto out; 13888ed61dc3SMiklos Szeredi 1389d80172c2SAmir Goldstein d_type = err; 1390d80172c2SAmir Goldstein if (!d_type) 13911bd0a3aeSlijiazi pr_warn("upper fs needs to support d_type.\n"); 13928ed61dc3SMiklos Szeredi 13938ed61dc3SMiklos Szeredi /* Check if upper/work fs supports O_TMPFILE */ 1394ad204488SMiklos Szeredi temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); 1395ad204488SMiklos Szeredi ofs->tmpfile = !IS_ERR(temp); 1396ad204488SMiklos Szeredi if (ofs->tmpfile) 13978ed61dc3SMiklos Szeredi dput(temp); 13988ed61dc3SMiklos Szeredi else 13991bd0a3aeSlijiazi pr_warn("upper fs does not support tmpfile.\n"); 14008ed61dc3SMiklos Szeredi 1401cad218abSAmir Goldstein 1402cad218abSAmir Goldstein /* Check if upper/work fs supports RENAME_WHITEOUT */ 1403cad218abSAmir Goldstein err = ovl_check_rename_whiteout(ofs->workdir); 1404cad218abSAmir Goldstein if (err < 0) 1405cad218abSAmir Goldstein goto out; 1406cad218abSAmir Goldstein 1407d80172c2SAmir Goldstein rename_whiteout = err; 1408d80172c2SAmir Goldstein if (!rename_whiteout) 1409cad218abSAmir Goldstein pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); 1410cad218abSAmir Goldstein 14118ed61dc3SMiklos Szeredi /* 14122d2f2d73SMiklos Szeredi * Check if upper/work fs supports (trusted|user).overlay.* xattr 14138ed61dc3SMiklos Szeredi */ 1414*c914c0e2SAmir Goldstein err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); 14158ed61dc3SMiklos Szeredi if (err) { 1416ad204488SMiklos Szeredi ofs->noxattr = true; 1417b0e0f697SAmir Goldstein if (ofs->config.index || ofs->config.metacopy) { 1418a683737bSAmir Goldstein ofs->config.index = false; 1419d5791044SVivek Goyal ofs->config.metacopy = false; 1420b0e0f697SAmir Goldstein pr_warn("upper fs does not support xattr, falling back to index=off,metacopy=off.\n"); 1421b0e0f697SAmir Goldstein } 1422b0e0f697SAmir Goldstein /* 1423b0e0f697SAmir Goldstein * xattr support is required for persistent st_ino. 1424b0e0f697SAmir Goldstein * Without persistent st_ino, xino=auto falls back to xino=off. 1425b0e0f697SAmir Goldstein */ 1426b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO) { 1427b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 1428b0e0f697SAmir Goldstein pr_warn("upper fs does not support xattr, falling back to xino=off.\n"); 1429b0e0f697SAmir Goldstein } 14302ba9d57eSAmir Goldstein err = 0; 14318ed61dc3SMiklos Szeredi } else { 1432*c914c0e2SAmir Goldstein ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); 14338ed61dc3SMiklos Szeredi } 14348ed61dc3SMiklos Szeredi 1435d80172c2SAmir Goldstein /* 1436d80172c2SAmir Goldstein * We allowed sub-optimal upper fs configuration and don't want to break 1437d80172c2SAmir Goldstein * users over kernel upgrade, but we never allowed remote upper fs, so 1438d80172c2SAmir Goldstein * we can enforce strict requirements for remote upper fs. 1439d80172c2SAmir Goldstein */ 1440d80172c2SAmir Goldstein if (ovl_dentry_remote(ofs->workdir) && 1441d80172c2SAmir Goldstein (!d_type || !rename_whiteout || ofs->noxattr)) { 1442d80172c2SAmir Goldstein pr_err("upper fs missing required features.\n"); 1443d80172c2SAmir Goldstein err = -EINVAL; 1444d80172c2SAmir Goldstein goto out; 1445d80172c2SAmir Goldstein } 1446d80172c2SAmir Goldstein 1447c86243b0SVivek Goyal /* 1448c86243b0SVivek Goyal * For volatile mount, create a incompat/volatile/dirty file to keep 1449c86243b0SVivek Goyal * track of it. 1450c86243b0SVivek Goyal */ 1451c86243b0SVivek Goyal if (ofs->config.ovl_volatile) { 1452c86243b0SVivek Goyal err = ovl_create_volatile_dirty(ofs); 1453c86243b0SVivek Goyal if (err < 0) { 1454c86243b0SVivek Goyal pr_err("Failed to create volatile/dirty file.\n"); 1455c86243b0SVivek Goyal goto out; 1456c86243b0SVivek Goyal } 1457c86243b0SVivek Goyal } 1458c86243b0SVivek Goyal 14598ed61dc3SMiklos Szeredi /* Check if upper/work fs supports file handles */ 1460e487d889SAmir Goldstein fh_type = ovl_can_decode_fh(ofs->workdir->d_sb); 1461e487d889SAmir Goldstein if (ofs->config.index && !fh_type) { 1462ad204488SMiklos Szeredi ofs->config.index = false; 14631bd0a3aeSlijiazi pr_warn("upper fs does not support file handles, falling back to index=off.\n"); 14648ed61dc3SMiklos Szeredi } 14658ed61dc3SMiklos Szeredi 1466e487d889SAmir Goldstein /* Check if upper fs has 32bit inode numbers */ 1467e487d889SAmir Goldstein if (fh_type != FILEID_INO32_GEN) 14680f831ec8SAmir Goldstein ofs->xino_mode = -1; 1469e487d889SAmir Goldstein 1470f168f109SAmir Goldstein /* NFS export of r/w mount depends on index */ 1471f168f109SAmir Goldstein if (ofs->config.nfs_export && !ofs->config.index) { 14721bd0a3aeSlijiazi pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n"); 1473f168f109SAmir Goldstein ofs->config.nfs_export = false; 1474f168f109SAmir Goldstein } 14752ba9d57eSAmir Goldstein out: 14762ba9d57eSAmir Goldstein mnt_drop_write(mnt); 14772ba9d57eSAmir Goldstein return err; 14788ed61dc3SMiklos Szeredi } 14798ed61dc3SMiklos Szeredi 1480146d62e5SAmir Goldstein static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, 1481146d62e5SAmir Goldstein struct path *upperpath) 1482520d7c86SMiklos Szeredi { 1483520d7c86SMiklos Szeredi int err; 1484bca44b52SMiklos Szeredi struct path workpath = { }; 1485520d7c86SMiklos Szeredi 1486ad204488SMiklos Szeredi err = ovl_mount_dir(ofs->config.workdir, &workpath); 1487520d7c86SMiklos Szeredi if (err) 1488520d7c86SMiklos Szeredi goto out; 1489520d7c86SMiklos Szeredi 1490520d7c86SMiklos Szeredi err = -EINVAL; 1491bca44b52SMiklos Szeredi if (upperpath->mnt != workpath.mnt) { 14921bd0a3aeSlijiazi pr_err("workdir and upperdir must reside under the same mount\n"); 1493520d7c86SMiklos Szeredi goto out; 1494520d7c86SMiklos Szeredi } 1495bca44b52SMiklos Szeredi if (!ovl_workdir_ok(workpath.dentry, upperpath->dentry)) { 14961bd0a3aeSlijiazi pr_err("workdir and upperdir must be separate subtrees\n"); 1497520d7c86SMiklos Szeredi goto out; 1498520d7c86SMiklos Szeredi } 1499520d7c86SMiklos Szeredi 15008c25741aSMiklos Szeredi ofs->workbasedir = dget(workpath.dentry); 15018c25741aSMiklos Szeredi 15028c25741aSMiklos Szeredi if (ovl_inuse_trylock(ofs->workbasedir)) { 1503ad204488SMiklos Szeredi ofs->workdir_locked = true; 1504520d7c86SMiklos Szeredi } else { 15050be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "workdir"); 15060be0bfd2SAmir Goldstein if (err) 15070be0bfd2SAmir Goldstein goto out; 1508520d7c86SMiklos Szeredi } 1509520d7c86SMiklos Szeredi 15100be0bfd2SAmir Goldstein err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap, 15110be0bfd2SAmir Goldstein "workdir"); 15120be0bfd2SAmir Goldstein if (err) 15130be0bfd2SAmir Goldstein goto out; 15140be0bfd2SAmir Goldstein 1515146d62e5SAmir Goldstein err = ovl_make_workdir(sb, ofs, &workpath); 1516bca44b52SMiklos Szeredi 1517520d7c86SMiklos Szeredi out: 1518bca44b52SMiklos Szeredi path_put(&workpath); 1519bca44b52SMiklos Szeredi 1520520d7c86SMiklos Szeredi return err; 1521520d7c86SMiklos Szeredi } 1522520d7c86SMiklos Szeredi 1523146d62e5SAmir Goldstein static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, 1524146d62e5SAmir Goldstein struct ovl_entry *oe, struct path *upperpath) 1525f7e3a7d9SMiklos Szeredi { 152608f4c7c8SMiklos Szeredi struct vfsmount *mnt = ovl_upper_mnt(ofs); 1527235ce9edSAmir Goldstein struct dentry *indexdir; 1528f7e3a7d9SMiklos Szeredi int err; 1529f7e3a7d9SMiklos Szeredi 15302ba9d57eSAmir Goldstein err = mnt_want_write(mnt); 15312ba9d57eSAmir Goldstein if (err) 15322ba9d57eSAmir Goldstein return err; 15332ba9d57eSAmir Goldstein 1534f7e3a7d9SMiklos Szeredi /* Verify lower root is upper root origin */ 1535610afc0bSMiklos Szeredi err = ovl_verify_origin(ofs, upperpath->dentry, 1536610afc0bSMiklos Szeredi oe->lowerstack[0].dentry, true); 1537f7e3a7d9SMiklos Szeredi if (err) { 15381bd0a3aeSlijiazi pr_err("failed to verify upper root origin\n"); 1539f7e3a7d9SMiklos Szeredi goto out; 1540f7e3a7d9SMiklos Szeredi } 1541f7e3a7d9SMiklos Szeredi 154220396365SAmir Goldstein /* index dir will act also as workdir */ 154320396365SAmir Goldstein iput(ofs->workdir_trap); 154420396365SAmir Goldstein ofs->workdir_trap = NULL; 154520396365SAmir Goldstein dput(ofs->workdir); 1546470c1563SAmir Goldstein ofs->workdir = NULL; 1547235ce9edSAmir Goldstein indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); 1548235ce9edSAmir Goldstein if (IS_ERR(indexdir)) { 1549235ce9edSAmir Goldstein err = PTR_ERR(indexdir); 1550235ce9edSAmir Goldstein } else if (indexdir) { 1551235ce9edSAmir Goldstein ofs->indexdir = indexdir; 1552235ce9edSAmir Goldstein ofs->workdir = dget(indexdir); 155320396365SAmir Goldstein 1554146d62e5SAmir Goldstein err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, 1555146d62e5SAmir Goldstein "indexdir"); 1556146d62e5SAmir Goldstein if (err) 1557146d62e5SAmir Goldstein goto out; 1558146d62e5SAmir Goldstein 1559ad1d615cSAmir Goldstein /* 1560ad1d615cSAmir Goldstein * Verify upper root is exclusively associated with index dir. 15612d2f2d73SMiklos Szeredi * Older kernels stored upper fh in ".overlay.origin" 1562ad1d615cSAmir Goldstein * xattr. If that xattr exists, verify that it is a match to 1563ad1d615cSAmir Goldstein * upper dir file handle. In any case, verify or set xattr 15642d2f2d73SMiklos Szeredi * ".overlay.upper" to indicate that index may have 1565ad1d615cSAmir Goldstein * directory entries. 1566ad1d615cSAmir Goldstein */ 1567610afc0bSMiklos Szeredi if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { 1568610afc0bSMiklos Szeredi err = ovl_verify_set_fh(ofs, ofs->indexdir, 1569610afc0bSMiklos Szeredi OVL_XATTR_ORIGIN, 1570ad1d615cSAmir Goldstein upperpath->dentry, true, false); 1571f7e3a7d9SMiklos Szeredi if (err) 15721bd0a3aeSlijiazi pr_err("failed to verify index dir 'origin' xattr\n"); 1573ad1d615cSAmir Goldstein } 1574610afc0bSMiklos Szeredi err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, 1575610afc0bSMiklos Szeredi true); 1576ad1d615cSAmir Goldstein if (err) 15771bd0a3aeSlijiazi pr_err("failed to verify index dir 'upper' xattr\n"); 1578f7e3a7d9SMiklos Szeredi 1579f7e3a7d9SMiklos Szeredi /* Cleanup bad/stale/orphan index entries */ 1580f7e3a7d9SMiklos Szeredi if (!err) 15811eff1a1dSAmir Goldstein err = ovl_indexdir_cleanup(ofs); 1582f7e3a7d9SMiklos Szeredi } 1583ad204488SMiklos Szeredi if (err || !ofs->indexdir) 15841bd0a3aeSlijiazi pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); 1585f7e3a7d9SMiklos Szeredi 1586f7e3a7d9SMiklos Szeredi out: 15872ba9d57eSAmir Goldstein mnt_drop_write(mnt); 1588f7e3a7d9SMiklos Szeredi return err; 1589f7e3a7d9SMiklos Szeredi } 1590f7e3a7d9SMiklos Szeredi 15919df085f3SAmir Goldstein static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) 15925148626bSAmir Goldstein { 15935148626bSAmir Goldstein unsigned int i; 15949df085f3SAmir Goldstein 159508f4c7c8SMiklos Szeredi if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) 15969df085f3SAmir Goldstein return true; 15979df085f3SAmir Goldstein 1598a888db31SAmir Goldstein /* 1599a888db31SAmir Goldstein * We allow using single lower with null uuid for index and nfs_export 1600a888db31SAmir Goldstein * for example to support those features with single lower squashfs. 1601a888db31SAmir Goldstein * To avoid regressions in setups of overlay with re-formatted lower 1602a888db31SAmir Goldstein * squashfs, do not allow decoding origin with lower null uuid unless 1603a888db31SAmir Goldstein * user opted-in to one of the new features that require following the 1604a888db31SAmir Goldstein * lower inode of non-dir upper. 1605a888db31SAmir Goldstein */ 1606ca45275cSVyacheslav Yurkov if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) 1607a888db31SAmir Goldstein return false; 1608a888db31SAmir Goldstein 16091b81ddddSAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 16109df085f3SAmir Goldstein /* 16119df085f3SAmir Goldstein * We use uuid to associate an overlay lower file handle with a 16129df085f3SAmir Goldstein * lower layer, so we can accept lower fs with null uuid as long 16139df085f3SAmir Goldstein * as all lower layers with null uuid are on the same fs. 16147e63c87fSAmir Goldstein * if we detect multiple lower fs with the same uuid, we 16157e63c87fSAmir Goldstein * disable lower file handle decoding on all of them. 16169df085f3SAmir Goldstein */ 16171b81ddddSAmir Goldstein if (ofs->fs[i].is_lower && 16181b81ddddSAmir Goldstein uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) { 161907f1e596SAmir Goldstein ofs->fs[i].bad_uuid = true; 16209df085f3SAmir Goldstein return false; 16219df085f3SAmir Goldstein } 16227e63c87fSAmir Goldstein } 16239df085f3SAmir Goldstein return true; 16249df085f3SAmir Goldstein } 16259df085f3SAmir Goldstein 16269df085f3SAmir Goldstein /* Get a unique fsid for the layer */ 16279df085f3SAmir Goldstein static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) 16289df085f3SAmir Goldstein { 16299df085f3SAmir Goldstein struct super_block *sb = path->mnt->mnt_sb; 16309df085f3SAmir Goldstein unsigned int i; 16315148626bSAmir Goldstein dev_t dev; 16325148626bSAmir Goldstein int err; 16337e63c87fSAmir Goldstein bool bad_uuid = false; 1634b0e0f697SAmir Goldstein bool warn = false; 16355148626bSAmir Goldstein 163607f1e596SAmir Goldstein for (i = 0; i < ofs->numfs; i++) { 163707f1e596SAmir Goldstein if (ofs->fs[i].sb == sb) 163807f1e596SAmir Goldstein return i; 16395148626bSAmir Goldstein } 16405148626bSAmir Goldstein 16419df085f3SAmir Goldstein if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { 16427e63c87fSAmir Goldstein bad_uuid = true; 1643b0e0f697SAmir Goldstein if (ofs->config.xino == OVL_XINO_AUTO) { 1644b0e0f697SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 1645b0e0f697SAmir Goldstein warn = true; 1646b0e0f697SAmir Goldstein } 16477e63c87fSAmir Goldstein if (ofs->config.index || ofs->config.nfs_export) { 16489df085f3SAmir Goldstein ofs->config.index = false; 16499df085f3SAmir Goldstein ofs->config.nfs_export = false; 1650b0e0f697SAmir Goldstein warn = true; 1651b0e0f697SAmir Goldstein } 1652b0e0f697SAmir Goldstein if (warn) { 1653b0e0f697SAmir Goldstein pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", 16547e63c87fSAmir Goldstein uuid_is_null(&sb->s_uuid) ? "null" : 16557e63c87fSAmir Goldstein "conflicting", 1656b0e0f697SAmir Goldstein path->dentry, ovl_xino_str[ofs->config.xino]); 16579df085f3SAmir Goldstein } 16587e63c87fSAmir Goldstein } 16599df085f3SAmir Goldstein 16605148626bSAmir Goldstein err = get_anon_bdev(&dev); 16615148626bSAmir Goldstein if (err) { 16621bd0a3aeSlijiazi pr_err("failed to get anonymous bdev for lowerpath\n"); 16635148626bSAmir Goldstein return err; 16645148626bSAmir Goldstein } 16655148626bSAmir Goldstein 166607f1e596SAmir Goldstein ofs->fs[ofs->numfs].sb = sb; 166707f1e596SAmir Goldstein ofs->fs[ofs->numfs].pseudo_dev = dev; 166807f1e596SAmir Goldstein ofs->fs[ofs->numfs].bad_uuid = bad_uuid; 16695148626bSAmir Goldstein 167007f1e596SAmir Goldstein return ofs->numfs++; 16715148626bSAmir Goldstein } 16725148626bSAmir Goldstein 167394375f9dSAmir Goldstein static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, 1674b8e42a65SMiklos Szeredi struct path *stack, unsigned int numlower, 1675b8e42a65SMiklos Szeredi struct ovl_layer *layers) 1676520d7c86SMiklos Szeredi { 1677520d7c86SMiklos Szeredi int err; 1678520d7c86SMiklos Szeredi unsigned int i; 1679520d7c86SMiklos Szeredi 1680520d7c86SMiklos Szeredi err = -ENOMEM; 168107f1e596SAmir Goldstein ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); 168207f1e596SAmir Goldstein if (ofs->fs == NULL) 16835148626bSAmir Goldstein goto out; 16845148626bSAmir Goldstein 168507f1e596SAmir Goldstein /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ 168607f1e596SAmir Goldstein ofs->numfs++; 168707f1e596SAmir Goldstein 168807f1e596SAmir Goldstein /* 1689b7bf9908SAmir Goldstein * All lower layers that share the same fs as upper layer, use the same 1690b7bf9908SAmir Goldstein * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower 1691b7bf9908SAmir Goldstein * only overlay to simplify ovl_fs_free(). 16921b81ddddSAmir Goldstein * is_lower will be set if upper fs is shared with a lower layer. 169307f1e596SAmir Goldstein */ 1694b7bf9908SAmir Goldstein err = get_anon_bdev(&ofs->fs[0].pseudo_dev); 1695b7bf9908SAmir Goldstein if (err) { 1696b7bf9908SAmir Goldstein pr_err("failed to get anonymous bdev for upper fs\n"); 1697b7bf9908SAmir Goldstein goto out; 1698b7bf9908SAmir Goldstein } 1699b7bf9908SAmir Goldstein 170008f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 170108f4c7c8SMiklos Szeredi ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; 17021b81ddddSAmir Goldstein ofs->fs[0].is_lower = false; 170307f1e596SAmir Goldstein } 170407f1e596SAmir Goldstein 1705520d7c86SMiklos Szeredi for (i = 0; i < numlower; i++) { 1706520d7c86SMiklos Szeredi struct vfsmount *mnt; 1707146d62e5SAmir Goldstein struct inode *trap; 17085148626bSAmir Goldstein int fsid; 1709520d7c86SMiklos Szeredi 17109df085f3SAmir Goldstein err = fsid = ovl_get_fsid(ofs, &stack[i]); 17115148626bSAmir Goldstein if (err < 0) 1712520d7c86SMiklos Szeredi goto out; 1713520d7c86SMiklos Szeredi 171424f14009Syoungjun /* 171524f14009Syoungjun * Check if lower root conflicts with this overlay layers before 171624f14009Syoungjun * checking if it is in-use as upperdir/workdir of "another" 171724f14009Syoungjun * mount, because we do not bother to check in ovl_is_inuse() if 171824f14009Syoungjun * the upperdir/workdir is in fact in-use by our 171924f14009Syoungjun * upperdir/workdir. 172024f14009Syoungjun */ 1721146d62e5SAmir Goldstein err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); 1722146d62e5SAmir Goldstein if (err) 1723146d62e5SAmir Goldstein goto out; 1724146d62e5SAmir Goldstein 17250be0bfd2SAmir Goldstein if (ovl_is_inuse(stack[i].dentry)) { 17260be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, "lowerdir"); 172724f14009Syoungjun if (err) { 172824f14009Syoungjun iput(trap); 17290be0bfd2SAmir Goldstein goto out; 17300be0bfd2SAmir Goldstein } 173124f14009Syoungjun } 17320be0bfd2SAmir Goldstein 1733520d7c86SMiklos Szeredi mnt = clone_private_mount(&stack[i]); 1734520d7c86SMiklos Szeredi err = PTR_ERR(mnt); 1735520d7c86SMiklos Szeredi if (IS_ERR(mnt)) { 17361bd0a3aeSlijiazi pr_err("failed to clone lowerpath\n"); 1737146d62e5SAmir Goldstein iput(trap); 1738520d7c86SMiklos Szeredi goto out; 1739520d7c86SMiklos Szeredi } 17405148626bSAmir Goldstein 1741520d7c86SMiklos Szeredi /* 1742520d7c86SMiklos Szeredi * Make lower layers R/O. That way fchmod/fchown on lower file 1743520d7c86SMiklos Szeredi * will fail instead of modifying lower fs. 1744520d7c86SMiklos Szeredi */ 1745520d7c86SMiklos Szeredi mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; 1746520d7c86SMiklos Szeredi 174713464165SMiklos Szeredi layers[ofs->numlayer].trap = trap; 174813464165SMiklos Szeredi layers[ofs->numlayer].mnt = mnt; 174913464165SMiklos Szeredi layers[ofs->numlayer].idx = ofs->numlayer; 175013464165SMiklos Szeredi layers[ofs->numlayer].fsid = fsid; 175113464165SMiklos Szeredi layers[ofs->numlayer].fs = &ofs->fs[fsid]; 175294375f9dSAmir Goldstein ofs->numlayer++; 17531b81ddddSAmir Goldstein ofs->fs[fsid].is_lower = true; 1754520d7c86SMiklos Szeredi } 1755e487d889SAmir Goldstein 1756795939a9SAmir Goldstein /* 1757795939a9SAmir Goldstein * When all layers on same fs, overlay can use real inode numbers. 1758926e94d7SAmir Goldstein * With mount option "xino=<on|auto>", mounter declares that there are 1759926e94d7SAmir Goldstein * enough free high bits in underlying fs to hold the unique fsid. 1760795939a9SAmir Goldstein * If overlayfs does encounter underlying inodes using the high xino 1761795939a9SAmir Goldstein * bits reserved for fsid, it emits a warning and uses the original 1762dfe51d47SAmir Goldstein * inode number or a non persistent inode number allocated from a 1763dfe51d47SAmir Goldstein * dedicated range. 1764795939a9SAmir Goldstein */ 176508f4c7c8SMiklos Szeredi if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { 17660f831ec8SAmir Goldstein if (ofs->config.xino == OVL_XINO_ON) 17670f831ec8SAmir Goldstein pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); 17680f831ec8SAmir Goldstein ofs->xino_mode = 0; 176953afcd31SAmir Goldstein } else if (ofs->config.xino == OVL_XINO_OFF) { 177053afcd31SAmir Goldstein ofs->xino_mode = -1; 1771926e94d7SAmir Goldstein } else if (ofs->xino_mode < 0) { 1772795939a9SAmir Goldstein /* 177307f1e596SAmir Goldstein * This is a roundup of number of bits needed for encoding 1774dfe51d47SAmir Goldstein * fsid, where fsid 0 is reserved for upper fs (even with 1775dfe51d47SAmir Goldstein * lower only overlay) +1 extra bit is reserved for the non 1776dfe51d47SAmir Goldstein * persistent inode number range that is used for resolving 1777dfe51d47SAmir Goldstein * xino lower bits overflow. 1778795939a9SAmir Goldstein */ 1779dfe51d47SAmir Goldstein BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); 1780dfe51d47SAmir Goldstein ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; 1781795939a9SAmir Goldstein } 1782795939a9SAmir Goldstein 17830f831ec8SAmir Goldstein if (ofs->xino_mode > 0) { 17841bd0a3aeSlijiazi pr_info("\"xino\" feature enabled using %d upper inode bits.\n", 17850f831ec8SAmir Goldstein ofs->xino_mode); 1786795939a9SAmir Goldstein } 1787e487d889SAmir Goldstein 1788520d7c86SMiklos Szeredi err = 0; 1789520d7c86SMiklos Szeredi out: 1790520d7c86SMiklos Szeredi return err; 1791520d7c86SMiklos Szeredi } 1792520d7c86SMiklos Szeredi 17934155c10aSMiklos Szeredi static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, 1794b8e42a65SMiklos Szeredi const char *lower, unsigned int numlower, 1795b8e42a65SMiklos Szeredi struct ovl_fs *ofs, struct ovl_layer *layers) 179653dbb0b4SMiklos Szeredi { 179753dbb0b4SMiklos Szeredi int err; 17984155c10aSMiklos Szeredi struct path *stack = NULL; 1799b8e42a65SMiklos Szeredi unsigned int i; 18004155c10aSMiklos Szeredi struct ovl_entry *oe; 180153dbb0b4SMiklos Szeredi 1802b8e42a65SMiklos Szeredi if (!ofs->config.upperdir && numlower == 1) { 18031bd0a3aeSlijiazi pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); 1804b8e42a65SMiklos Szeredi return ERR_PTR(-EINVAL); 180553dbb0b4SMiklos Szeredi } 180653dbb0b4SMiklos Szeredi 1807b8e42a65SMiklos Szeredi stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); 180853dbb0b4SMiklos Szeredi if (!stack) 1809b8e42a65SMiklos Szeredi return ERR_PTR(-ENOMEM); 181053dbb0b4SMiklos Szeredi 181153dbb0b4SMiklos Szeredi err = -EINVAL; 1812b8e42a65SMiklos Szeredi for (i = 0; i < numlower; i++) { 1813b8e42a65SMiklos Szeredi err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); 181453dbb0b4SMiklos Szeredi if (err) 18154155c10aSMiklos Szeredi goto out_err; 181653dbb0b4SMiklos Szeredi 181753dbb0b4SMiklos Szeredi lower = strchr(lower, '\0') + 1; 181853dbb0b4SMiklos Szeredi } 181953dbb0b4SMiklos Szeredi 182053dbb0b4SMiklos Szeredi err = -EINVAL; 182153dbb0b4SMiklos Szeredi sb->s_stack_depth++; 182253dbb0b4SMiklos Szeredi if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { 18231bd0a3aeSlijiazi pr_err("maximum fs stacking depth exceeded\n"); 18244155c10aSMiklos Szeredi goto out_err; 182553dbb0b4SMiklos Szeredi } 182653dbb0b4SMiklos Szeredi 1827b8e42a65SMiklos Szeredi err = ovl_get_layers(sb, ofs, stack, numlower, layers); 18284155c10aSMiklos Szeredi if (err) 18294155c10aSMiklos Szeredi goto out_err; 18304155c10aSMiklos Szeredi 18314155c10aSMiklos Szeredi err = -ENOMEM; 18324155c10aSMiklos Szeredi oe = ovl_alloc_entry(numlower); 18334155c10aSMiklos Szeredi if (!oe) 18344155c10aSMiklos Szeredi goto out_err; 18354155c10aSMiklos Szeredi 18364155c10aSMiklos Szeredi for (i = 0; i < numlower; i++) { 18374155c10aSMiklos Szeredi oe->lowerstack[i].dentry = dget(stack[i].dentry); 183894375f9dSAmir Goldstein oe->lowerstack[i].layer = &ofs->layers[i+1]; 18394155c10aSMiklos Szeredi } 184053dbb0b4SMiklos Szeredi 184153dbb0b4SMiklos Szeredi out: 184253dbb0b4SMiklos Szeredi for (i = 0; i < numlower; i++) 184353dbb0b4SMiklos Szeredi path_put(&stack[i]); 184453dbb0b4SMiklos Szeredi kfree(stack); 18454155c10aSMiklos Szeredi 18464155c10aSMiklos Szeredi return oe; 18474155c10aSMiklos Szeredi 18484155c10aSMiklos Szeredi out_err: 18494155c10aSMiklos Szeredi oe = ERR_PTR(err); 185053dbb0b4SMiklos Szeredi goto out; 185153dbb0b4SMiklos Szeredi } 185253dbb0b4SMiklos Szeredi 1853146d62e5SAmir Goldstein /* 1854146d62e5SAmir Goldstein * Check if this layer root is a descendant of: 1855146d62e5SAmir Goldstein * - another layer of this overlayfs instance 1856146d62e5SAmir Goldstein * - upper/work dir of any overlayfs instance 1857146d62e5SAmir Goldstein */ 18580be0bfd2SAmir Goldstein static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, 1859708fa015SMiklos Szeredi struct dentry *dentry, const char *name, 1860708fa015SMiklos Szeredi bool is_lower) 1861146d62e5SAmir Goldstein { 18629179c21dSMiklos Szeredi struct dentry *next = dentry, *parent; 1863146d62e5SAmir Goldstein int err = 0; 1864146d62e5SAmir Goldstein 18659179c21dSMiklos Szeredi if (!dentry) 1866146d62e5SAmir Goldstein return 0; 1867146d62e5SAmir Goldstein 1868146d62e5SAmir Goldstein parent = dget_parent(next); 18699179c21dSMiklos Szeredi 18709179c21dSMiklos Szeredi /* Walk back ancestors to root (inclusive) looking for traps */ 18719179c21dSMiklos Szeredi while (!err && parent != next) { 1872708fa015SMiklos Szeredi if (is_lower && ovl_lookup_trap_inode(sb, parent)) { 1873146d62e5SAmir Goldstein err = -ELOOP; 18741bd0a3aeSlijiazi pr_err("overlapping %s path\n", name); 18750be0bfd2SAmir Goldstein } else if (ovl_is_inuse(parent)) { 18760be0bfd2SAmir Goldstein err = ovl_report_in_use(ofs, name); 1877146d62e5SAmir Goldstein } 1878146d62e5SAmir Goldstein next = parent; 18799179c21dSMiklos Szeredi parent = dget_parent(next); 18809179c21dSMiklos Szeredi dput(next); 1881146d62e5SAmir Goldstein } 1882146d62e5SAmir Goldstein 18839179c21dSMiklos Szeredi dput(parent); 1884146d62e5SAmir Goldstein 1885146d62e5SAmir Goldstein return err; 1886146d62e5SAmir Goldstein } 1887146d62e5SAmir Goldstein 1888146d62e5SAmir Goldstein /* 1889146d62e5SAmir Goldstein * Check if any of the layers or work dirs overlap. 1890146d62e5SAmir Goldstein */ 1891146d62e5SAmir Goldstein static int ovl_check_overlapping_layers(struct super_block *sb, 1892146d62e5SAmir Goldstein struct ovl_fs *ofs) 1893146d62e5SAmir Goldstein { 1894146d62e5SAmir Goldstein int i, err; 1895146d62e5SAmir Goldstein 189608f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs)) { 189708f4c7c8SMiklos Szeredi err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, 1898708fa015SMiklos Szeredi "upperdir", false); 1899146d62e5SAmir Goldstein if (err) 1900146d62e5SAmir Goldstein return err; 1901146d62e5SAmir Goldstein 1902146d62e5SAmir Goldstein /* 1903146d62e5SAmir Goldstein * Checking workbasedir avoids hitting ovl_is_inuse(parent) of 1904146d62e5SAmir Goldstein * this instance and covers overlapping work and index dirs, 1905146d62e5SAmir Goldstein * unless work or index dir have been moved since created inside 1906146d62e5SAmir Goldstein * workbasedir. In that case, we already have their traps in 1907146d62e5SAmir Goldstein * inode cache and we will catch that case on lookup. 1908146d62e5SAmir Goldstein */ 1909708fa015SMiklos Szeredi err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", 1910708fa015SMiklos Szeredi false); 1911146d62e5SAmir Goldstein if (err) 1912146d62e5SAmir Goldstein return err; 1913146d62e5SAmir Goldstein } 1914146d62e5SAmir Goldstein 191594375f9dSAmir Goldstein for (i = 1; i < ofs->numlayer; i++) { 19160be0bfd2SAmir Goldstein err = ovl_check_layer(sb, ofs, 191794375f9dSAmir Goldstein ofs->layers[i].mnt->mnt_root, 1918708fa015SMiklos Szeredi "lowerdir", true); 1919146d62e5SAmir Goldstein if (err) 1920146d62e5SAmir Goldstein return err; 1921146d62e5SAmir Goldstein } 1922146d62e5SAmir Goldstein 1923146d62e5SAmir Goldstein return 0; 1924146d62e5SAmir Goldstein } 1925146d62e5SAmir Goldstein 19262effc5c2SAmir Goldstein static struct dentry *ovl_get_root(struct super_block *sb, 19272effc5c2SAmir Goldstein struct dentry *upperdentry, 19282effc5c2SAmir Goldstein struct ovl_entry *oe) 19292effc5c2SAmir Goldstein { 19302effc5c2SAmir Goldstein struct dentry *root; 193162c832edSAmir Goldstein struct ovl_path *lowerpath = &oe->lowerstack[0]; 193262c832edSAmir Goldstein unsigned long ino = d_inode(lowerpath->dentry)->i_ino; 193362c832edSAmir Goldstein int fsid = lowerpath->layer->fsid; 193462c832edSAmir Goldstein struct ovl_inode_params oip = { 193562c832edSAmir Goldstein .upperdentry = upperdentry, 193662c832edSAmir Goldstein .lowerpath = lowerpath, 193762c832edSAmir Goldstein }; 19382effc5c2SAmir Goldstein 19392effc5c2SAmir Goldstein root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); 19402effc5c2SAmir Goldstein if (!root) 19412effc5c2SAmir Goldstein return NULL; 19422effc5c2SAmir Goldstein 19432effc5c2SAmir Goldstein root->d_fsdata = oe; 19442effc5c2SAmir Goldstein 19452effc5c2SAmir Goldstein if (upperdentry) { 194662c832edSAmir Goldstein /* Root inode uses upper st_ino/i_ino */ 194762c832edSAmir Goldstein ino = d_inode(upperdentry)->i_ino; 194862c832edSAmir Goldstein fsid = 0; 19492effc5c2SAmir Goldstein ovl_dentry_set_upper_alias(root); 1950610afc0bSMiklos Szeredi if (ovl_is_impuredir(sb, upperdentry)) 19512effc5c2SAmir Goldstein ovl_set_flag(OVL_IMPURE, d_inode(root)); 19522effc5c2SAmir Goldstein } 19532effc5c2SAmir Goldstein 19542effc5c2SAmir Goldstein /* Root is always merge -> can have whiteouts */ 19552effc5c2SAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); 19562effc5c2SAmir Goldstein ovl_dentry_set_flag(OVL_E_CONNECTED, root); 19572effc5c2SAmir Goldstein ovl_set_upperdata(d_inode(root)); 195862c832edSAmir Goldstein ovl_inode_init(d_inode(root), &oip, ino, fsid); 1959f4288844SMiklos Szeredi ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); 19602effc5c2SAmir Goldstein 19612effc5c2SAmir Goldstein return root; 19622effc5c2SAmir Goldstein } 19632effc5c2SAmir Goldstein 1964e9be9d5eSMiklos Szeredi static int ovl_fill_super(struct super_block *sb, void *data, int silent) 1965e9be9d5eSMiklos Szeredi { 196633006cdfSKees Cook struct path upperpath = { }; 1967e9be9d5eSMiklos Szeredi struct dentry *root_dentry; 19684155c10aSMiklos Szeredi struct ovl_entry *oe; 1969ad204488SMiklos Szeredi struct ovl_fs *ofs; 1970b8e42a65SMiklos Szeredi struct ovl_layer *layers; 197151f8f3c4SKonstantin Khlebnikov struct cred *cred; 1972b8e42a65SMiklos Szeredi char *splitlower = NULL; 1973b8e42a65SMiklos Szeredi unsigned int numlower; 1974e9be9d5eSMiklos Szeredi int err; 1975e9be9d5eSMiklos Szeredi 19769efb069dSMiklos Szeredi err = -EIO; 19779efb069dSMiklos Szeredi if (WARN_ON(sb->s_user_ns != current_user_ns())) 19789efb069dSMiklos Szeredi goto out; 19799efb069dSMiklos Szeredi 1980f4288844SMiklos Szeredi sb->s_d_op = &ovl_dentry_operations; 1981f4288844SMiklos Szeredi 1982f45827e8SErez Zadok err = -ENOMEM; 1983ad204488SMiklos Szeredi ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); 1984ad204488SMiklos Szeredi if (!ofs) 1985e9be9d5eSMiklos Szeredi goto out; 1986e9be9d5eSMiklos Szeredi 1987d7b49b10SChengguang Xu err = -ENOMEM; 1988ad204488SMiklos Szeredi ofs->creator_cred = cred = prepare_creds(); 1989c6fe6254SMiklos Szeredi if (!cred) 1990c6fe6254SMiklos Szeredi goto out_err; 1991c6fe6254SMiklos Szeredi 1992c21c839bSChengguang Xu /* Is there a reason anyone would want not to share whiteouts? */ 1993c21c839bSChengguang Xu ofs->share_whiteout = true; 1994c21c839bSChengguang Xu 1995ad204488SMiklos Szeredi ofs->config.index = ovl_index_def; 19965830fb6bSPavel Tikhomirov ofs->config.uuid = true; 1997f168f109SAmir Goldstein ofs->config.nfs_export = ovl_nfs_export_def; 1998795939a9SAmir Goldstein ofs->config.xino = ovl_xino_def(); 1999d5791044SVivek Goyal ofs->config.metacopy = ovl_metacopy_def; 2000ad204488SMiklos Szeredi err = ovl_parse_opt((char *) data, &ofs->config); 2001f45827e8SErez Zadok if (err) 2002a9075cdbSMiklos Szeredi goto out_err; 2003f45827e8SErez Zadok 2004e9be9d5eSMiklos Szeredi err = -EINVAL; 2005ad204488SMiklos Szeredi if (!ofs->config.lowerdir) { 200607f2af7bSKonstantin Khlebnikov if (!silent) 20071bd0a3aeSlijiazi pr_err("missing 'lowerdir'\n"); 2008a9075cdbSMiklos Szeredi goto out_err; 200953a08cb9SMiklos Szeredi } 201053a08cb9SMiklos Szeredi 2011b8e42a65SMiklos Szeredi err = -ENOMEM; 2012b8e42a65SMiklos Szeredi splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); 2013b8e42a65SMiklos Szeredi if (!splitlower) 2014b8e42a65SMiklos Szeredi goto out_err; 2015b8e42a65SMiklos Szeredi 2016d7b49b10SChengguang Xu err = -EINVAL; 2017b8e42a65SMiklos Szeredi numlower = ovl_split_lowerdirs(splitlower); 2018b8e42a65SMiklos Szeredi if (numlower > OVL_MAX_STACK) { 2019b8e42a65SMiklos Szeredi pr_err("too many lower directories, limit is %d\n", 2020b8e42a65SMiklos Szeredi OVL_MAX_STACK); 2021b8e42a65SMiklos Szeredi goto out_err; 2022b8e42a65SMiklos Szeredi } 2023b8e42a65SMiklos Szeredi 2024d7b49b10SChengguang Xu err = -ENOMEM; 2025b8e42a65SMiklos Szeredi layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); 2026b8e42a65SMiklos Szeredi if (!layers) 2027b8e42a65SMiklos Szeredi goto out_err; 2028b8e42a65SMiklos Szeredi 2029b8e42a65SMiklos Szeredi ofs->layers = layers; 2030b8e42a65SMiklos Szeredi /* Layer 0 is reserved for upper even if there's no upper */ 2031b8e42a65SMiklos Szeredi ofs->numlayer = 1; 2032b8e42a65SMiklos Szeredi 203353a08cb9SMiklos Szeredi sb->s_stack_depth = 0; 2034cf9a6784SMiklos Szeredi sb->s_maxbytes = MAX_LFS_FILESIZE; 20354d314f78SAmir Goldstein atomic_long_set(&ofs->last_ino, 1); 2036e487d889SAmir Goldstein /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ 203753afcd31SAmir Goldstein if (ofs->config.xino != OVL_XINO_OFF) { 20380f831ec8SAmir Goldstein ofs->xino_mode = BITS_PER_LONG - 32; 203953afcd31SAmir Goldstein if (!ofs->xino_mode) { 204053afcd31SAmir Goldstein pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n"); 204153afcd31SAmir Goldstein ofs->config.xino = OVL_XINO_OFF; 204253afcd31SAmir Goldstein } 204353afcd31SAmir Goldstein } 2044795939a9SAmir Goldstein 2045146d62e5SAmir Goldstein /* alloc/destroy_inode needed for setting up traps in inode cache */ 2046146d62e5SAmir Goldstein sb->s_op = &ovl_super_operations; 2047146d62e5SAmir Goldstein 2048ad204488SMiklos Szeredi if (ofs->config.upperdir) { 2049335d3fc5SSargun Dhillon struct super_block *upper_sb; 2050335d3fc5SSargun Dhillon 2051d7b49b10SChengguang Xu err = -EINVAL; 2052ad204488SMiklos Szeredi if (!ofs->config.workdir) { 20531bd0a3aeSlijiazi pr_err("missing 'workdir'\n"); 2054a9075cdbSMiklos Szeredi goto out_err; 2055e9be9d5eSMiklos Szeredi } 2056e9be9d5eSMiklos Szeredi 2057b8e42a65SMiklos Szeredi err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); 205821a3b317SMiklos Szeredi if (err) 2059a9075cdbSMiklos Szeredi goto out_err; 2060d719e8f2SMiklos Szeredi 2061335d3fc5SSargun Dhillon upper_sb = ovl_upper_mnt(ofs)->mnt_sb; 2062335d3fc5SSargun Dhillon if (!ovl_should_sync(ofs)) { 2063335d3fc5SSargun Dhillon ofs->errseq = errseq_sample(&upper_sb->s_wb_err); 2064335d3fc5SSargun Dhillon if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { 2065335d3fc5SSargun Dhillon err = -EIO; 2066335d3fc5SSargun Dhillon pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); 2067335d3fc5SSargun Dhillon goto out_err; 2068335d3fc5SSargun Dhillon } 2069335d3fc5SSargun Dhillon } 2070335d3fc5SSargun Dhillon 2071146d62e5SAmir Goldstein err = ovl_get_workdir(sb, ofs, &upperpath); 20728ed61dc3SMiklos Szeredi if (err) 2073a9075cdbSMiklos Szeredi goto out_err; 2074c6fe6254SMiklos Szeredi 2075ad204488SMiklos Szeredi if (!ofs->workdir) 20761751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 20776e88256eSMiklos Szeredi 2078335d3fc5SSargun Dhillon sb->s_stack_depth = upper_sb->s_stack_depth; 2079335d3fc5SSargun Dhillon sb->s_time_gran = upper_sb->s_time_gran; 208021765194SVivek Goyal } 2081b8e42a65SMiklos Szeredi oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); 20824155c10aSMiklos Szeredi err = PTR_ERR(oe); 20834155c10aSMiklos Szeredi if (IS_ERR(oe)) 2084a9075cdbSMiklos Szeredi goto out_err; 2085e9be9d5eSMiklos Szeredi 208671cbad7eShujianyang /* If the upper fs is nonexistent, we mark overlayfs r/o too */ 208708f4c7c8SMiklos Szeredi if (!ovl_upper_mnt(ofs)) 20881751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 2089e9be9d5eSMiklos Szeredi 20905830fb6bSPavel Tikhomirov if (!ofs->config.uuid && ofs->numfs > 1) { 20915830fb6bSPavel Tikhomirov pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); 20925830fb6bSPavel Tikhomirov ofs->config.uuid = true; 20935830fb6bSPavel Tikhomirov } 20945830fb6bSPavel Tikhomirov 2095470c1563SAmir Goldstein if (!ovl_force_readonly(ofs) && ofs->config.index) { 2096146d62e5SAmir Goldstein err = ovl_get_indexdir(sb, ofs, oe, &upperpath); 209754fb347eSAmir Goldstein if (err) 20984155c10aSMiklos Szeredi goto out_free_oe; 20996e88256eSMiklos Szeredi 2100972d0093SAmir Goldstein /* Force r/o mount with no index dir */ 210120396365SAmir Goldstein if (!ofs->indexdir) 21021751e8a6SLinus Torvalds sb->s_flags |= SB_RDONLY; 210302bcd157SAmir Goldstein } 210402bcd157SAmir Goldstein 2105146d62e5SAmir Goldstein err = ovl_check_overlapping_layers(sb, ofs); 2106146d62e5SAmir Goldstein if (err) 2107146d62e5SAmir Goldstein goto out_free_oe; 2108146d62e5SAmir Goldstein 2109972d0093SAmir Goldstein /* Show index=off in /proc/mounts for forced r/o mount */ 2110f168f109SAmir Goldstein if (!ofs->indexdir) { 2111ad204488SMiklos Szeredi ofs->config.index = false; 211208f4c7c8SMiklos Szeredi if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { 21131bd0a3aeSlijiazi pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); 2114f168f109SAmir Goldstein ofs->config.nfs_export = false; 2115f168f109SAmir Goldstein } 2116f168f109SAmir Goldstein } 211702bcd157SAmir Goldstein 2118d5791044SVivek Goyal if (ofs->config.metacopy && ofs->config.nfs_export) { 21191bd0a3aeSlijiazi pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n"); 2120d5791044SVivek Goyal ofs->config.nfs_export = false; 2121d5791044SVivek Goyal } 2122d5791044SVivek Goyal 21238383f174SAmir Goldstein if (ofs->config.nfs_export) 21248383f174SAmir Goldstein sb->s_export_op = &ovl_export_operations; 21258383f174SAmir Goldstein 212651f8f3c4SKonstantin Khlebnikov /* Never override disk quota limits or use reserved space */ 212751f8f3c4SKonstantin Khlebnikov cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); 212851f8f3c4SKonstantin Khlebnikov 2129655042ccSVivek Goyal sb->s_magic = OVERLAYFS_SUPER_MAGIC; 21302d2f2d73SMiklos Szeredi sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : 21312d2f2d73SMiklos Szeredi ovl_trusted_xattr_handlers; 2132ad204488SMiklos Szeredi sb->s_fs_info = ofs; 2133de2a4a50SMiklos Szeredi sb->s_flags |= SB_POSIXACL; 213432b1924bSKonstantin Khlebnikov sb->s_iflags |= SB_I_SKIP_SYNC; 2135655042ccSVivek Goyal 2136c6fe6254SMiklos Szeredi err = -ENOMEM; 21372effc5c2SAmir Goldstein root_dentry = ovl_get_root(sb, upperpath.dentry, oe); 2138e9be9d5eSMiklos Szeredi if (!root_dentry) 21394155c10aSMiklos Szeredi goto out_free_oe; 2140e9be9d5eSMiklos Szeredi 2141e9be9d5eSMiklos Szeredi mntput(upperpath.mnt); 2142b8e42a65SMiklos Szeredi kfree(splitlower); 2143ed06e069SMiklos Szeredi 2144e9be9d5eSMiklos Szeredi sb->s_root = root_dentry; 2145e9be9d5eSMiklos Szeredi 2146e9be9d5eSMiklos Szeredi return 0; 2147e9be9d5eSMiklos Szeredi 21484155c10aSMiklos Szeredi out_free_oe: 21494155c10aSMiklos Szeredi ovl_entry_stack_free(oe); 2150b9343632SChandan Rajendra kfree(oe); 21514155c10aSMiklos Szeredi out_err: 2152b8e42a65SMiklos Szeredi kfree(splitlower); 2153e9be9d5eSMiklos Szeredi path_put(&upperpath); 2154ad204488SMiklos Szeredi ovl_free_fs(ofs); 2155e9be9d5eSMiklos Szeredi out: 2156e9be9d5eSMiklos Szeredi return err; 2157e9be9d5eSMiklos Szeredi } 2158e9be9d5eSMiklos Szeredi 2159e9be9d5eSMiklos Szeredi static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, 2160e9be9d5eSMiklos Szeredi const char *dev_name, void *raw_data) 2161e9be9d5eSMiklos Szeredi { 2162e9be9d5eSMiklos Szeredi return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); 2163e9be9d5eSMiklos Szeredi } 2164e9be9d5eSMiklos Szeredi 2165e9be9d5eSMiklos Szeredi static struct file_system_type ovl_fs_type = { 2166e9be9d5eSMiklos Szeredi .owner = THIS_MODULE, 2167ef94b186SMiklos Szeredi .name = "overlay", 2168459c7c56SMiklos Szeredi .fs_flags = FS_USERNS_MOUNT, 2169e9be9d5eSMiklos Szeredi .mount = ovl_mount, 2170e9be9d5eSMiklos Szeredi .kill_sb = kill_anon_super, 2171e9be9d5eSMiklos Szeredi }; 2172ef94b186SMiklos Szeredi MODULE_ALIAS_FS("overlay"); 2173e9be9d5eSMiklos Szeredi 217413cf199dSAmir Goldstein static void ovl_inode_init_once(void *foo) 217513cf199dSAmir Goldstein { 217613cf199dSAmir Goldstein struct ovl_inode *oi = foo; 217713cf199dSAmir Goldstein 217813cf199dSAmir Goldstein inode_init_once(&oi->vfs_inode); 217913cf199dSAmir Goldstein } 218013cf199dSAmir Goldstein 2181e9be9d5eSMiklos Szeredi static int __init ovl_init(void) 2182e9be9d5eSMiklos Szeredi { 218313cf199dSAmir Goldstein int err; 218413cf199dSAmir Goldstein 218513cf199dSAmir Goldstein ovl_inode_cachep = kmem_cache_create("ovl_inode", 218613cf199dSAmir Goldstein sizeof(struct ovl_inode), 0, 218713cf199dSAmir Goldstein (SLAB_RECLAIM_ACCOUNT| 218813cf199dSAmir Goldstein SLAB_MEM_SPREAD|SLAB_ACCOUNT), 218913cf199dSAmir Goldstein ovl_inode_init_once); 219013cf199dSAmir Goldstein if (ovl_inode_cachep == NULL) 219113cf199dSAmir Goldstein return -ENOMEM; 219213cf199dSAmir Goldstein 21932406a307SJiufei Xue err = ovl_aio_request_cache_init(); 21942406a307SJiufei Xue if (!err) { 219513cf199dSAmir Goldstein err = register_filesystem(&ovl_fs_type); 21962406a307SJiufei Xue if (!err) 21972406a307SJiufei Xue return 0; 21982406a307SJiufei Xue 21992406a307SJiufei Xue ovl_aio_request_cache_destroy(); 22002406a307SJiufei Xue } 220113cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 220213cf199dSAmir Goldstein 220313cf199dSAmir Goldstein return err; 2204e9be9d5eSMiklos Szeredi } 2205e9be9d5eSMiklos Szeredi 2206e9be9d5eSMiklos Szeredi static void __exit ovl_exit(void) 2207e9be9d5eSMiklos Szeredi { 2208e9be9d5eSMiklos Szeredi unregister_filesystem(&ovl_fs_type); 220913cf199dSAmir Goldstein 221013cf199dSAmir Goldstein /* 221113cf199dSAmir Goldstein * Make sure all delayed rcu free inodes are flushed before we 221213cf199dSAmir Goldstein * destroy cache. 221313cf199dSAmir Goldstein */ 221413cf199dSAmir Goldstein rcu_barrier(); 221513cf199dSAmir Goldstein kmem_cache_destroy(ovl_inode_cachep); 22162406a307SJiufei Xue ovl_aio_request_cache_destroy(); 2217e9be9d5eSMiklos Szeredi } 2218e9be9d5eSMiklos Szeredi 2219e9be9d5eSMiklos Szeredi module_init(ovl_init); 2220e9be9d5eSMiklos Szeredi module_exit(ovl_exit); 2221