1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2e9be9d5eSMiklos Szeredi /* 3e9be9d5eSMiklos Szeredi * 4e9be9d5eSMiklos Szeredi * Copyright (C) 2011 Novell Inc. 5e9be9d5eSMiklos Szeredi */ 6e9be9d5eSMiklos Szeredi 7e9be9d5eSMiklos Szeredi #include <linux/fs.h> 8e9be9d5eSMiklos Szeredi #include <linux/slab.h> 95b825c3aSIngo Molnar #include <linux/cred.h> 10e9be9d5eSMiklos Szeredi #include <linux/xattr.h> 115201dc44SMiklos Szeredi #include <linux/posix_acl.h> 125f8415d6SAmir Goldstein #include <linux/ratelimit.h> 1310c5db28SChristoph Hellwig #include <linux/fiemap.h> 14e9be9d5eSMiklos Szeredi #include "overlayfs.h" 15e9be9d5eSMiklos Szeredi 16ba1e563cSChandan Rajendra 17*549c7297SChristian Brauner int ovl_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, 18*549c7297SChristian Brauner struct iattr *attr) 19e9be9d5eSMiklos Szeredi { 20e9be9d5eSMiklos Szeredi int err; 21997336f2SVivek Goyal bool full_copy_up = false; 22e9be9d5eSMiklos Szeredi struct dentry *upperdentry; 231175b6b8SVivek Goyal const struct cred *old_cred; 24e9be9d5eSMiklos Szeredi 252f221d6fSChristian Brauner err = setattr_prepare(&init_user_ns, dentry, attr); 26cf9a6784SMiklos Szeredi if (err) 27cf9a6784SMiklos Szeredi return err; 28cf9a6784SMiklos Szeredi 29e9be9d5eSMiklos Szeredi err = ovl_want_write(dentry); 30e9be9d5eSMiklos Szeredi if (err) 31e9be9d5eSMiklos Szeredi goto out; 32e9be9d5eSMiklos Szeredi 335812160eSMiklos Szeredi if (attr->ia_valid & ATTR_SIZE) { 345812160eSMiklos Szeredi struct inode *realinode = d_inode(ovl_dentry_real(dentry)); 355812160eSMiklos Szeredi 365812160eSMiklos Szeredi err = -ETXTBSY; 375812160eSMiklos Szeredi if (atomic_read(&realinode->i_writecount) < 0) 385812160eSMiklos Szeredi goto out_drop_write; 39997336f2SVivek Goyal 40997336f2SVivek Goyal /* Truncate should trigger data copy up as well */ 41997336f2SVivek Goyal full_copy_up = true; 425812160eSMiklos Szeredi } 435812160eSMiklos Szeredi 44997336f2SVivek Goyal if (!full_copy_up) 45acff81ecSMiklos Szeredi err = ovl_copy_up(dentry); 46997336f2SVivek Goyal else 47997336f2SVivek Goyal err = ovl_copy_up_with_data(dentry); 48acff81ecSMiklos Szeredi if (!err) { 495812160eSMiklos Szeredi struct inode *winode = NULL; 505812160eSMiklos Szeredi 51e9be9d5eSMiklos Szeredi upperdentry = ovl_dentry_upper(dentry); 52acff81ecSMiklos Szeredi 535812160eSMiklos Szeredi if (attr->ia_valid & ATTR_SIZE) { 545812160eSMiklos Szeredi winode = d_inode(upperdentry); 555812160eSMiklos Szeredi err = get_write_access(winode); 565812160eSMiklos Szeredi if (err) 575812160eSMiklos Szeredi goto out_drop_write; 585812160eSMiklos Szeredi } 595812160eSMiklos Szeredi 60b99c2d91SMiklos Szeredi if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) 61b99c2d91SMiklos Szeredi attr->ia_valid &= ~ATTR_MODE; 62b99c2d91SMiklos Szeredi 63e67f0216SVivek Goyal /* 6415fd2ea9SVivek Goyal * We might have to translate ovl file into real file object 6515fd2ea9SVivek Goyal * once use cases emerge. For now, simply don't let underlying 6615fd2ea9SVivek Goyal * filesystem rely on attr->ia_file 67e67f0216SVivek Goyal */ 68e67f0216SVivek Goyal attr->ia_valid &= ~ATTR_FILE; 69e67f0216SVivek Goyal 7015fd2ea9SVivek Goyal /* 7115fd2ea9SVivek Goyal * If open(O_TRUNC) is done, VFS calls ->setattr with ATTR_OPEN 7215fd2ea9SVivek Goyal * set. Overlayfs does not pass O_TRUNC flag to underlying 7315fd2ea9SVivek Goyal * filesystem during open -> do not pass ATTR_OPEN. This 7415fd2ea9SVivek Goyal * disables optimization in fuse which assumes open(O_TRUNC) 7515fd2ea9SVivek Goyal * already set file size to 0. But we never passed O_TRUNC to 7615fd2ea9SVivek Goyal * fuse. So by clearing ATTR_OPEN, fuse will be forced to send 7715fd2ea9SVivek Goyal * setattr request to server. 7815fd2ea9SVivek Goyal */ 7915fd2ea9SVivek Goyal attr->ia_valid &= ~ATTR_OPEN; 8015fd2ea9SVivek Goyal 815955102cSAl Viro inode_lock(upperdentry->d_inode); 821175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 832f221d6fSChristian Brauner err = notify_change(&init_user_ns, upperdentry, attr, NULL); 841175b6b8SVivek Goyal revert_creds(old_cred); 85b81de061SKonstantin Khlebnikov if (!err) 86b81de061SKonstantin Khlebnikov ovl_copyattr(upperdentry->d_inode, dentry->d_inode); 875955102cSAl Viro inode_unlock(upperdentry->d_inode); 885812160eSMiklos Szeredi 895812160eSMiklos Szeredi if (winode) 905812160eSMiklos Szeredi put_write_access(winode); 91e9be9d5eSMiklos Szeredi } 925812160eSMiklos Szeredi out_drop_write: 93e9be9d5eSMiklos Szeredi ovl_drop_write(dentry); 94e9be9d5eSMiklos Szeredi out: 95e9be9d5eSMiklos Szeredi return err; 96e9be9d5eSMiklos Szeredi } 97e9be9d5eSMiklos Szeredi 9807f1e596SAmir Goldstein static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, int fsid) 99da309e8cSAmir Goldstein { 1000f831ec8SAmir Goldstein bool samefs = ovl_same_fs(dentry->d_sb); 101e487d889SAmir Goldstein unsigned int xinobits = ovl_xino_bits(dentry->d_sb); 102dfe51d47SAmir Goldstein unsigned int xinoshift = 64 - xinobits; 103da309e8cSAmir Goldstein 104da309e8cSAmir Goldstein if (samefs) { 105da309e8cSAmir Goldstein /* 106da309e8cSAmir Goldstein * When all layers are on the same fs, all real inode 107da309e8cSAmir Goldstein * number are unique, so we use the overlay st_dev, 108da309e8cSAmir Goldstein * which is friendly to du -x. 109da309e8cSAmir Goldstein */ 110da309e8cSAmir Goldstein stat->dev = dentry->d_sb->s_dev; 111e487d889SAmir Goldstein return 0; 112e487d889SAmir Goldstein } else if (xinobits) { 113e487d889SAmir Goldstein /* 114e487d889SAmir Goldstein * All inode numbers of underlying fs should not be using the 115e487d889SAmir Goldstein * high xinobits, so we use high xinobits to partition the 116e487d889SAmir Goldstein * overlay st_ino address space. The high bits holds the fsid 117dfe51d47SAmir Goldstein * (upper fsid is 0). The lowest xinobit is reserved for mapping 118dfe51d47SAmir Goldstein * the non-peresistent inode numbers range in case of overflow. 119dfe51d47SAmir Goldstein * This way all overlay inode numbers are unique and use the 120dfe51d47SAmir Goldstein * overlay st_dev. 121e487d889SAmir Goldstein */ 122926e94d7SAmir Goldstein if (likely(!(stat->ino >> xinoshift))) { 123dfe51d47SAmir Goldstein stat->ino |= ((u64)fsid) << (xinoshift + 1); 124e487d889SAmir Goldstein stat->dev = dentry->d_sb->s_dev; 125e487d889SAmir Goldstein return 0; 126926e94d7SAmir Goldstein } else if (ovl_xino_warn(dentry->d_sb)) { 127926e94d7SAmir Goldstein pr_warn_ratelimited("inode number too big (%pd2, ino=%llu, xinobits=%d)\n", 128926e94d7SAmir Goldstein dentry, stat->ino, xinobits); 129e487d889SAmir Goldstein } 130e487d889SAmir Goldstein } 131e487d889SAmir Goldstein 132e487d889SAmir Goldstein /* The inode could not be mapped to a unified st_ino address space */ 133e487d889SAmir Goldstein if (S_ISDIR(dentry->d_inode->i_mode)) { 134da309e8cSAmir Goldstein /* 135da309e8cSAmir Goldstein * Always use the overlay st_dev for directories, so 'find 136da309e8cSAmir Goldstein * -xdev' will scan the entire overlay mount and won't cross the 137da309e8cSAmir Goldstein * overlay mount boundaries. 138da309e8cSAmir Goldstein * 139da309e8cSAmir Goldstein * If not all layers are on the same fs the pair {real st_ino; 140da309e8cSAmir Goldstein * overlay st_dev} is not unique, so use the non persistent 141da309e8cSAmir Goldstein * overlay st_ino for directories. 142da309e8cSAmir Goldstein */ 143da309e8cSAmir Goldstein stat->dev = dentry->d_sb->s_dev; 144da309e8cSAmir Goldstein stat->ino = dentry->d_inode->i_ino; 145b7bf9908SAmir Goldstein } else { 146da309e8cSAmir Goldstein /* 147da309e8cSAmir Goldstein * For non-samefs setup, if we cannot map all layers st_ino 148da309e8cSAmir Goldstein * to a unified address space, we need to make sure that st_dev 149b7bf9908SAmir Goldstein * is unique per underlying fs, so we use the unique anonymous 150b7bf9908SAmir Goldstein * bdev assigned to the underlying fs. 151da309e8cSAmir Goldstein */ 15207f1e596SAmir Goldstein stat->dev = OVL_FS(dentry->d_sb)->fs[fsid].pseudo_dev; 153da309e8cSAmir Goldstein } 154da309e8cSAmir Goldstein 155da309e8cSAmir Goldstein return 0; 156da309e8cSAmir Goldstein } 157da309e8cSAmir Goldstein 158*549c7297SChristian Brauner int ovl_getattr(struct user_namespace *mnt_userns, const struct path *path, 159*549c7297SChristian Brauner struct kstat *stat, u32 request_mask, unsigned int flags) 160e9be9d5eSMiklos Szeredi { 161a528d35eSDavid Howells struct dentry *dentry = path->dentry; 16272b608f0SAmir Goldstein enum ovl_path_type type; 163e9be9d5eSMiklos Szeredi struct path realpath; 1641175b6b8SVivek Goyal const struct cred *old_cred; 1655b712091SMiklos Szeredi bool is_dir = S_ISDIR(dentry->d_inode->i_mode); 16607f1e596SAmir Goldstein int fsid = 0; 1671175b6b8SVivek Goyal int err; 16867d756c2SVivek Goyal bool metacopy_blocks = false; 16967d756c2SVivek Goyal 17067d756c2SVivek Goyal metacopy_blocks = ovl_is_metacopy_dentry(dentry); 171e9be9d5eSMiklos Szeredi 17272b608f0SAmir Goldstein type = ovl_path_real(dentry, &realpath); 1731175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 174a528d35eSDavid Howells err = vfs_getattr(&realpath, stat, request_mask, flags); 17572b608f0SAmir Goldstein if (err) 17672b608f0SAmir Goldstein goto out; 17772b608f0SAmir Goldstein 17872b608f0SAmir Goldstein /* 179da309e8cSAmir Goldstein * For non-dir or same fs, we use st_ino of the copy up origin. 180da309e8cSAmir Goldstein * This guaranties constant st_dev/st_ino across copy up. 181e487d889SAmir Goldstein * With xino feature and non-samefs, we use st_ino of the copy up 182e487d889SAmir Goldstein * origin masked with high bits that represent the layer id. 18372b608f0SAmir Goldstein * 184da309e8cSAmir Goldstein * If lower filesystem supports NFS file handles, this also guaranties 18572b608f0SAmir Goldstein * persistent st_ino across mount cycle. 18672b608f0SAmir Goldstein */ 1870f831ec8SAmir Goldstein if (!is_dir || ovl_same_dev(dentry->d_sb)) { 188da309e8cSAmir Goldstein if (!OVL_TYPE_UPPER(type)) { 18907f1e596SAmir Goldstein fsid = ovl_layer_lower(dentry)->fsid; 190da309e8cSAmir Goldstein } else if (OVL_TYPE_ORIGIN(type)) { 19172b608f0SAmir Goldstein struct kstat lowerstat; 19267d756c2SVivek Goyal u32 lowermask = STATX_INO | STATX_BLOCKS | 19367d756c2SVivek Goyal (!is_dir ? STATX_NLINK : 0); 19472b608f0SAmir Goldstein 19572b608f0SAmir Goldstein ovl_path_lower(dentry, &realpath); 19672b608f0SAmir Goldstein err = vfs_getattr(&realpath, &lowerstat, 1975b712091SMiklos Szeredi lowermask, flags); 19872b608f0SAmir Goldstein if (err) 19972b608f0SAmir Goldstein goto out; 20072b608f0SAmir Goldstein 20172b608f0SAmir Goldstein /* 202359f392cSAmir Goldstein * Lower hardlinks may be broken on copy up to different 20372b608f0SAmir Goldstein * upper files, so we cannot use the lower origin st_ino 20472b608f0SAmir Goldstein * for those different files, even for the same fs case. 20586eaa130SAmir Goldstein * 20686eaa130SAmir Goldstein * Similarly, several redirected dirs can point to the 20786eaa130SAmir Goldstein * same dir on a lower layer. With the "verify_lower" 20886eaa130SAmir Goldstein * feature, we do not use the lower origin st_ino, if 20986eaa130SAmir Goldstein * we haven't verified that this redirect is unique. 21086eaa130SAmir Goldstein * 211359f392cSAmir Goldstein * With inodes index enabled, it is safe to use st_ino 21286eaa130SAmir Goldstein * of an indexed origin. The index validates that the 21386eaa130SAmir Goldstein * upper hardlink is not broken and that a redirected 21486eaa130SAmir Goldstein * dir is the only redirect to that origin. 21572b608f0SAmir Goldstein */ 21686eaa130SAmir Goldstein if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) || 21786eaa130SAmir Goldstein (!ovl_verify_lower(dentry->d_sb) && 2189f99e50dSAmir Goldstein (is_dir || lowerstat.nlink == 1))) { 21907f1e596SAmir Goldstein fsid = ovl_layer_lower(dentry)->fsid; 2209c6d8f13SAmir Goldstein stat->ino = lowerstat.ino; 22172b608f0SAmir Goldstein } 22267d756c2SVivek Goyal 22367d756c2SVivek Goyal /* 22467d756c2SVivek Goyal * If we are querying a metacopy dentry and lower 22567d756c2SVivek Goyal * dentry is data dentry, then use the blocks we 22667d756c2SVivek Goyal * queried just now. We don't have to do additional 22767d756c2SVivek Goyal * vfs_getattr(). If lower itself is metacopy, then 22867d756c2SVivek Goyal * additional vfs_getattr() is unavoidable. 22967d756c2SVivek Goyal */ 23067d756c2SVivek Goyal if (metacopy_blocks && 23167d756c2SVivek Goyal realpath.dentry == ovl_dentry_lowerdata(dentry)) { 23267d756c2SVivek Goyal stat->blocks = lowerstat.blocks; 23367d756c2SVivek Goyal metacopy_blocks = false; 23467d756c2SVivek Goyal } 23567d756c2SVivek Goyal } 23667d756c2SVivek Goyal 23767d756c2SVivek Goyal if (metacopy_blocks) { 23867d756c2SVivek Goyal /* 23967d756c2SVivek Goyal * If lower is not same as lowerdata or if there was 24067d756c2SVivek Goyal * no origin on upper, we can end up here. 24167d756c2SVivek Goyal */ 24267d756c2SVivek Goyal struct kstat lowerdatastat; 24367d756c2SVivek Goyal u32 lowermask = STATX_BLOCKS; 24467d756c2SVivek Goyal 24567d756c2SVivek Goyal ovl_path_lowerdata(dentry, &realpath); 24667d756c2SVivek Goyal err = vfs_getattr(&realpath, &lowerdatastat, 24767d756c2SVivek Goyal lowermask, flags); 24867d756c2SVivek Goyal if (err) 24967d756c2SVivek Goyal goto out; 25067d756c2SVivek Goyal stat->blocks = lowerdatastat.blocks; 2519f99e50dSAmir Goldstein } 252a0c5ad30SAmir Goldstein } 253da309e8cSAmir Goldstein 25407f1e596SAmir Goldstein err = ovl_map_dev_ino(dentry, stat, fsid); 255da309e8cSAmir Goldstein if (err) 256da309e8cSAmir Goldstein goto out; 2575b712091SMiklos Szeredi 2585b712091SMiklos Szeredi /* 2595b712091SMiklos Szeredi * It's probably not worth it to count subdirs to get the 2605b712091SMiklos Szeredi * correct link count. nlink=1 seems to pacify 'find' and 2615b712091SMiklos Szeredi * other utilities. 2625b712091SMiklos Szeredi */ 2635b712091SMiklos Szeredi if (is_dir && OVL_TYPE_MERGE(type)) 2645b712091SMiklos Szeredi stat->nlink = 1; 2655b712091SMiklos Szeredi 2665f8415d6SAmir Goldstein /* 2675f8415d6SAmir Goldstein * Return the overlay inode nlinks for indexed upper inodes. 2685f8415d6SAmir Goldstein * Overlay inode nlink counts the union of the upper hardlinks 2695f8415d6SAmir Goldstein * and non-covered lower hardlinks. It does not include the upper 2705f8415d6SAmir Goldstein * index hardlink. 2715f8415d6SAmir Goldstein */ 2725f8415d6SAmir Goldstein if (!is_dir && ovl_test_flag(OVL_INDEX, d_inode(dentry))) 2735f8415d6SAmir Goldstein stat->nlink = dentry->d_inode->i_nlink; 2745f8415d6SAmir Goldstein 27572b608f0SAmir Goldstein out: 2761175b6b8SVivek Goyal revert_creds(old_cred); 27772b608f0SAmir Goldstein 2781175b6b8SVivek Goyal return err; 279e9be9d5eSMiklos Szeredi } 280e9be9d5eSMiklos Szeredi 281*549c7297SChristian Brauner int ovl_permission(struct user_namespace *mnt_userns, 282*549c7297SChristian Brauner struct inode *inode, int mask) 283e9be9d5eSMiklos Szeredi { 28409d8b586SMiklos Szeredi struct inode *upperinode = ovl_inode_upper(inode); 28509d8b586SMiklos Szeredi struct inode *realinode = upperinode ?: ovl_inode_lower(inode); 286c0ca3d70SVivek Goyal const struct cred *old_cred; 287e9be9d5eSMiklos Szeredi int err; 288e9be9d5eSMiklos Szeredi 289e9be9d5eSMiklos Szeredi /* Careful in RCU walk mode */ 290e9be9d5eSMiklos Szeredi if (!realinode) { 291e9be9d5eSMiklos Szeredi WARN_ON(!(mask & MAY_NOT_BLOCK)); 292a999d7e1SMiklos Szeredi return -ECHILD; 293e9be9d5eSMiklos Szeredi } 294e9be9d5eSMiklos Szeredi 295c0ca3d70SVivek Goyal /* 296c0ca3d70SVivek Goyal * Check overlay inode with the creds of task and underlying inode 297c0ca3d70SVivek Goyal * with creds of mounter 298c0ca3d70SVivek Goyal */ 29947291baaSChristian Brauner err = generic_permission(&init_user_ns, inode, mask); 300c0ca3d70SVivek Goyal if (err) 301c0ca3d70SVivek Goyal return err; 302c0ca3d70SVivek Goyal 303ec7ba118SMiklos Szeredi old_cred = ovl_override_creds(inode->i_sb); 304ec7ba118SMiklos Szeredi if (!upperinode && 305ec7ba118SMiklos Szeredi !special_file(realinode->i_mode) && mask & MAY_WRITE) { 306754f8cb7SVivek Goyal mask &= ~(MAY_WRITE | MAY_APPEND); 307ec7ba118SMiklos Szeredi /* Make sure mounter can read file for copy up later */ 308500cac3cSVivek Goyal mask |= MAY_READ; 309500cac3cSVivek Goyal } 31047291baaSChristian Brauner err = inode_permission(&init_user_ns, realinode, mask); 311c0ca3d70SVivek Goyal revert_creds(old_cred); 312c0ca3d70SVivek Goyal 313c0ca3d70SVivek Goyal return err; 314e9be9d5eSMiklos Szeredi } 315e9be9d5eSMiklos Szeredi 3166b255391SAl Viro static const char *ovl_get_link(struct dentry *dentry, 317fceef393SAl Viro struct inode *inode, 318fceef393SAl Viro struct delayed_call *done) 319e9be9d5eSMiklos Szeredi { 3201175b6b8SVivek Goyal const struct cred *old_cred; 3211175b6b8SVivek Goyal const char *p; 322e9be9d5eSMiklos Szeredi 3236b255391SAl Viro if (!dentry) 3246b255391SAl Viro return ERR_PTR(-ECHILD); 3256b255391SAl Viro 3261175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 3277764235bSMiklos Szeredi p = vfs_get_link(ovl_dentry_real(dentry), done); 3281175b6b8SVivek Goyal revert_creds(old_cred); 3291175b6b8SVivek Goyal return p; 330e9be9d5eSMiklos Szeredi } 331e9be9d5eSMiklos Szeredi 332610afc0bSMiklos Szeredi bool ovl_is_private_xattr(struct super_block *sb, const char *name) 333e9be9d5eSMiklos Szeredi { 3342d2f2d73SMiklos Szeredi struct ovl_fs *ofs = sb->s_fs_info; 3352d2f2d73SMiklos Szeredi 3362d2f2d73SMiklos Szeredi if (ofs->config.userxattr) 3372d2f2d73SMiklos Szeredi return strncmp(name, OVL_XATTR_USER_PREFIX, 3382d2f2d73SMiklos Szeredi sizeof(OVL_XATTR_USER_PREFIX) - 1) == 0; 3392d2f2d73SMiklos Szeredi else 3402d2f2d73SMiklos Szeredi return strncmp(name, OVL_XATTR_TRUSTED_PREFIX, 3412d2f2d73SMiklos Szeredi sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1) == 0; 342e9be9d5eSMiklos Szeredi } 343e9be9d5eSMiklos Szeredi 3441d88f183SMiklos Szeredi int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, 3451d88f183SMiklos Szeredi const void *value, size_t size, int flags) 346e9be9d5eSMiklos Szeredi { 347e9be9d5eSMiklos Szeredi int err; 3481d88f183SMiklos Szeredi struct dentry *upperdentry = ovl_i_dentry_upper(inode); 3491d88f183SMiklos Szeredi struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); 3501175b6b8SVivek Goyal const struct cred *old_cred; 351e9be9d5eSMiklos Szeredi 352e9be9d5eSMiklos Szeredi err = ovl_want_write(dentry); 353e9be9d5eSMiklos Szeredi if (err) 354e9be9d5eSMiklos Szeredi goto out; 355e9be9d5eSMiklos Szeredi 3561d88f183SMiklos Szeredi if (!value && !upperdentry) { 357c7c7a1a1STycho Andersen err = vfs_getxattr(&init_user_ns, realdentry, name, NULL, 0); 3580e585cccSAndreas Gruenbacher if (err < 0) 3590e585cccSAndreas Gruenbacher goto out_drop_write; 3600e585cccSAndreas Gruenbacher } 3610e585cccSAndreas Gruenbacher 3621d88f183SMiklos Szeredi if (!upperdentry) { 363e9be9d5eSMiklos Szeredi err = ovl_copy_up(dentry); 364e9be9d5eSMiklos Szeredi if (err) 365e9be9d5eSMiklos Szeredi goto out_drop_write; 366e9be9d5eSMiklos Szeredi 3671d88f183SMiklos Szeredi realdentry = ovl_dentry_upper(dentry); 3681d88f183SMiklos Szeredi } 3690e585cccSAndreas Gruenbacher 3701175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 3710e585cccSAndreas Gruenbacher if (value) 372c7c7a1a1STycho Andersen err = vfs_setxattr(&init_user_ns, realdentry, name, value, size, 373c7c7a1a1STycho Andersen flags); 3740e585cccSAndreas Gruenbacher else { 3750e585cccSAndreas Gruenbacher WARN_ON(flags != XATTR_REPLACE); 376c7c7a1a1STycho Andersen err = vfs_removexattr(&init_user_ns, realdentry, name); 3770e585cccSAndreas Gruenbacher } 3781175b6b8SVivek Goyal revert_creds(old_cred); 379e9be9d5eSMiklos Szeredi 380d9854c87SMiklos Szeredi /* copy c/mtime */ 381d9854c87SMiklos Szeredi ovl_copyattr(d_inode(realdentry), inode); 382d9854c87SMiklos Szeredi 383e9be9d5eSMiklos Szeredi out_drop_write: 384e9be9d5eSMiklos Szeredi ovl_drop_write(dentry); 385e9be9d5eSMiklos Szeredi out: 386e9be9d5eSMiklos Szeredi return err; 387e9be9d5eSMiklos Szeredi } 388e9be9d5eSMiklos Szeredi 3891d88f183SMiklos Szeredi int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, 3900eb45fc3SAndreas Gruenbacher void *value, size_t size) 391e9be9d5eSMiklos Szeredi { 3921175b6b8SVivek Goyal ssize_t res; 3931175b6b8SVivek Goyal const struct cred *old_cred; 3941d88f183SMiklos Szeredi struct dentry *realdentry = 3951d88f183SMiklos Szeredi ovl_i_dentry_upper(inode) ?: ovl_dentry_lower(dentry); 39652148463SMiklos Szeredi 3971175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 398c7c7a1a1STycho Andersen res = vfs_getxattr(&init_user_ns, realdentry, name, value, size); 3991175b6b8SVivek Goyal revert_creds(old_cred); 4001175b6b8SVivek Goyal return res; 401e9be9d5eSMiklos Szeredi } 402e9be9d5eSMiklos Szeredi 403610afc0bSMiklos Szeredi static bool ovl_can_list(struct super_block *sb, const char *s) 404a082c6f6SMiklos Szeredi { 4058f6ee74cSMiklos Szeredi /* Never list private (.overlay) */ 4068f6ee74cSMiklos Szeredi if (ovl_is_private_xattr(sb, s)) 4078f6ee74cSMiklos Szeredi return false; 4088f6ee74cSMiklos Szeredi 409a082c6f6SMiklos Szeredi /* List all non-trusted xatts */ 410a082c6f6SMiklos Szeredi if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) 411a082c6f6SMiklos Szeredi return true; 412a082c6f6SMiklos Szeredi 4138f6ee74cSMiklos Szeredi /* list other trusted for superuser only */ 4148f6ee74cSMiklos Szeredi return ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); 415a082c6f6SMiklos Szeredi } 416a082c6f6SMiklos Szeredi 417e9be9d5eSMiklos Szeredi ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) 418e9be9d5eSMiklos Szeredi { 419b581755bSMiklos Szeredi struct dentry *realdentry = ovl_dentry_real(dentry); 420e9be9d5eSMiklos Szeredi ssize_t res; 4217cb35119SMiklos Szeredi size_t len; 4227cb35119SMiklos Szeredi char *s; 4231175b6b8SVivek Goyal const struct cred *old_cred; 424e9be9d5eSMiklos Szeredi 4251175b6b8SVivek Goyal old_cred = ovl_override_creds(dentry->d_sb); 426b581755bSMiklos Szeredi res = vfs_listxattr(realdentry, list, size); 4271175b6b8SVivek Goyal revert_creds(old_cred); 428e9be9d5eSMiklos Szeredi if (res <= 0 || size == 0) 429e9be9d5eSMiklos Szeredi return res; 430e9be9d5eSMiklos Szeredi 431e9be9d5eSMiklos Szeredi /* filter out private xattrs */ 4327cb35119SMiklos Szeredi for (s = list, len = res; len;) { 4337cb35119SMiklos Szeredi size_t slen = strnlen(s, len) + 1; 434e9be9d5eSMiklos Szeredi 4357cb35119SMiklos Szeredi /* underlying fs providing us with an broken xattr list? */ 4367cb35119SMiklos Szeredi if (WARN_ON(slen > len)) 4377cb35119SMiklos Szeredi return -EIO; 438e9be9d5eSMiklos Szeredi 4397cb35119SMiklos Szeredi len -= slen; 440610afc0bSMiklos Szeredi if (!ovl_can_list(dentry->d_sb, s)) { 441e9be9d5eSMiklos Szeredi res -= slen; 4427cb35119SMiklos Szeredi memmove(s, s + slen, len); 443e9be9d5eSMiklos Szeredi } else { 4447cb35119SMiklos Szeredi s += slen; 445e9be9d5eSMiklos Szeredi } 446e9be9d5eSMiklos Szeredi } 447e9be9d5eSMiklos Szeredi 448e9be9d5eSMiklos Szeredi return res; 449e9be9d5eSMiklos Szeredi } 450e9be9d5eSMiklos Szeredi 45139a25b2bSVivek Goyal struct posix_acl *ovl_get_acl(struct inode *inode, int type) 45239a25b2bSVivek Goyal { 45309d8b586SMiklos Szeredi struct inode *realinode = ovl_inode_real(inode); 4541175b6b8SVivek Goyal const struct cred *old_cred; 4551175b6b8SVivek Goyal struct posix_acl *acl; 45639a25b2bSVivek Goyal 4575201dc44SMiklos Szeredi if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode)) 45839a25b2bSVivek Goyal return NULL; 45939a25b2bSVivek Goyal 4601175b6b8SVivek Goyal old_cred = ovl_override_creds(inode->i_sb); 4615201dc44SMiklos Szeredi acl = get_acl(realinode, type); 4621175b6b8SVivek Goyal revert_creds(old_cred); 4631175b6b8SVivek Goyal 4641175b6b8SVivek Goyal return acl; 46539a25b2bSVivek Goyal } 46639a25b2bSVivek Goyal 46795582b00SDeepa Dinamani int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags) 468d719e8f2SMiklos Szeredi { 4698f35cf51SMiklos Szeredi if (flags & S_ATIME) { 4708f35cf51SMiklos Szeredi struct ovl_fs *ofs = inode->i_sb->s_fs_info; 4718f35cf51SMiklos Szeredi struct path upperpath = { 47208f4c7c8SMiklos Szeredi .mnt = ovl_upper_mnt(ofs), 4738f35cf51SMiklos Szeredi .dentry = ovl_upperdentry_dereference(OVL_I(inode)), 4748f35cf51SMiklos Szeredi }; 475d719e8f2SMiklos Szeredi 476d719e8f2SMiklos Szeredi if (upperpath.dentry) { 477d719e8f2SMiklos Szeredi touch_atime(&upperpath); 478d719e8f2SMiklos Szeredi inode->i_atime = d_inode(upperpath.dentry)->i_atime; 479d719e8f2SMiklos Szeredi } 4808f35cf51SMiklos Szeredi } 481d719e8f2SMiklos Szeredi return 0; 482d719e8f2SMiklos Szeredi } 483d719e8f2SMiklos Szeredi 4849e142c41SMiklos Szeredi static int ovl_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, 4859e142c41SMiklos Szeredi u64 start, u64 len) 4869e142c41SMiklos Szeredi { 4879e142c41SMiklos Szeredi int err; 488c11faf32SChengguang Xu struct inode *realinode = ovl_inode_realdata(inode); 4899e142c41SMiklos Szeredi const struct cred *old_cred; 4909e142c41SMiklos Szeredi 4919e142c41SMiklos Szeredi if (!realinode->i_op->fiemap) 4929e142c41SMiklos Szeredi return -EOPNOTSUPP; 4939e142c41SMiklos Szeredi 4949e142c41SMiklos Szeredi old_cred = ovl_override_creds(inode->i_sb); 4959e142c41SMiklos Szeredi err = realinode->i_op->fiemap(realinode, fieinfo, start, len); 4969e142c41SMiklos Szeredi revert_creds(old_cred); 4979e142c41SMiklos Szeredi 4989e142c41SMiklos Szeredi return err; 4999e142c41SMiklos Szeredi } 5009e142c41SMiklos Szeredi 501e9be9d5eSMiklos Szeredi static const struct inode_operations ovl_file_inode_operations = { 502e9be9d5eSMiklos Szeredi .setattr = ovl_setattr, 503e9be9d5eSMiklos Szeredi .permission = ovl_permission, 504e9be9d5eSMiklos Szeredi .getattr = ovl_getattr, 505e9be9d5eSMiklos Szeredi .listxattr = ovl_listxattr, 50639a25b2bSVivek Goyal .get_acl = ovl_get_acl, 507d719e8f2SMiklos Szeredi .update_time = ovl_update_time, 5089e142c41SMiklos Szeredi .fiemap = ovl_fiemap, 509e9be9d5eSMiklos Szeredi }; 510e9be9d5eSMiklos Szeredi 511e9be9d5eSMiklos Szeredi static const struct inode_operations ovl_symlink_inode_operations = { 512e9be9d5eSMiklos Szeredi .setattr = ovl_setattr, 5136b255391SAl Viro .get_link = ovl_get_link, 514e9be9d5eSMiklos Szeredi .getattr = ovl_getattr, 515e9be9d5eSMiklos Szeredi .listxattr = ovl_listxattr, 516d719e8f2SMiklos Szeredi .update_time = ovl_update_time, 517e9be9d5eSMiklos Szeredi }; 518e9be9d5eSMiklos Szeredi 5199e142c41SMiklos Szeredi static const struct inode_operations ovl_special_inode_operations = { 5209e142c41SMiklos Szeredi .setattr = ovl_setattr, 5219e142c41SMiklos Szeredi .permission = ovl_permission, 5229e142c41SMiklos Szeredi .getattr = ovl_getattr, 5239e142c41SMiklos Szeredi .listxattr = ovl_listxattr, 5249e142c41SMiklos Szeredi .get_acl = ovl_get_acl, 5259e142c41SMiklos Szeredi .update_time = ovl_update_time, 5269e142c41SMiklos Szeredi }; 5279e142c41SMiklos Szeredi 52869383c59SWei Yongjun static const struct address_space_operations ovl_aops = { 5295b910bd6SAmir Goldstein /* For O_DIRECT dentry_open() checks f_mapping->a_ops->direct_IO */ 5305b910bd6SAmir Goldstein .direct_IO = noop_direct_IO, 5315b910bd6SAmir Goldstein }; 5325b910bd6SAmir Goldstein 533b1eaa950SAmir Goldstein /* 534b1eaa950SAmir Goldstein * It is possible to stack overlayfs instance on top of another 535a5a84682SChengguang Xu * overlayfs instance as lower layer. We need to annotate the 536b1eaa950SAmir Goldstein * stackable i_mutex locks according to stack level of the super 537b1eaa950SAmir Goldstein * block instance. An overlayfs instance can never be in stack 538b1eaa950SAmir Goldstein * depth 0 (there is always a real fs below it). An overlayfs 539b1eaa950SAmir Goldstein * inode lock will use the lockdep annotaion ovl_i_mutex_key[depth]. 540b1eaa950SAmir Goldstein * 541b1eaa950SAmir Goldstein * For example, here is a snip from /proc/lockdep_chains after 542b1eaa950SAmir Goldstein * dir_iterate of nested overlayfs: 543b1eaa950SAmir Goldstein * 544b1eaa950SAmir Goldstein * [...] &ovl_i_mutex_dir_key[depth] (stack_depth=2) 545b1eaa950SAmir Goldstein * [...] &ovl_i_mutex_dir_key[depth]#2 (stack_depth=1) 546b1eaa950SAmir Goldstein * [...] &type->i_mutex_dir_key (stack_depth=0) 547b1f9d385SAmir Goldstein * 548b1f9d385SAmir Goldstein * Locking order w.r.t ovl_want_write() is important for nested overlayfs. 549b1f9d385SAmir Goldstein * 550b1f9d385SAmir Goldstein * This chain is valid: 551b1f9d385SAmir Goldstein * - inode->i_rwsem (inode_lock[2]) 552b1f9d385SAmir Goldstein * - upper_mnt->mnt_sb->s_writers (ovl_want_write[0]) 553b1f9d385SAmir Goldstein * - OVL_I(inode)->lock (ovl_inode_lock[2]) 554b1f9d385SAmir Goldstein * - OVL_I(lowerinode)->lock (ovl_inode_lock[1]) 555b1f9d385SAmir Goldstein * 556b1f9d385SAmir Goldstein * And this chain is valid: 557b1f9d385SAmir Goldstein * - inode->i_rwsem (inode_lock[2]) 558b1f9d385SAmir Goldstein * - OVL_I(inode)->lock (ovl_inode_lock[2]) 559b1f9d385SAmir Goldstein * - lowerinode->i_rwsem (inode_lock[1]) 560b1f9d385SAmir Goldstein * - OVL_I(lowerinode)->lock (ovl_inode_lock[1]) 561b1f9d385SAmir Goldstein * 562b1f9d385SAmir Goldstein * But lowerinode->i_rwsem SHOULD NOT be acquired while ovl_want_write() is 563b1f9d385SAmir Goldstein * held, because it is in reverse order of the non-nested case using the same 564b1f9d385SAmir Goldstein * upper fs: 565b1f9d385SAmir Goldstein * - inode->i_rwsem (inode_lock[1]) 566b1f9d385SAmir Goldstein * - upper_mnt->mnt_sb->s_writers (ovl_want_write[0]) 567b1f9d385SAmir Goldstein * - OVL_I(inode)->lock (ovl_inode_lock[1]) 568b1eaa950SAmir Goldstein */ 569b1eaa950SAmir Goldstein #define OVL_MAX_NESTING FILESYSTEM_MAX_STACK_DEPTH 570b1eaa950SAmir Goldstein 571b1eaa950SAmir Goldstein static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode) 572b1eaa950SAmir Goldstein { 573b1eaa950SAmir Goldstein #ifdef CONFIG_LOCKDEP 574b1eaa950SAmir Goldstein static struct lock_class_key ovl_i_mutex_key[OVL_MAX_NESTING]; 575b1eaa950SAmir Goldstein static struct lock_class_key ovl_i_mutex_dir_key[OVL_MAX_NESTING]; 5764eae06deSAmir Goldstein static struct lock_class_key ovl_i_lock_key[OVL_MAX_NESTING]; 577b1eaa950SAmir Goldstein 578b1eaa950SAmir Goldstein int depth = inode->i_sb->s_stack_depth - 1; 579b1eaa950SAmir Goldstein 580b1eaa950SAmir Goldstein if (WARN_ON_ONCE(depth < 0 || depth >= OVL_MAX_NESTING)) 581b1eaa950SAmir Goldstein depth = 0; 582b1eaa950SAmir Goldstein 583b1eaa950SAmir Goldstein if (S_ISDIR(inode->i_mode)) 584b1eaa950SAmir Goldstein lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_dir_key[depth]); 585b1eaa950SAmir Goldstein else 586b1eaa950SAmir Goldstein lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_key[depth]); 5874eae06deSAmir Goldstein 5884eae06deSAmir Goldstein lockdep_set_class(&OVL_I(inode)->lock, &ovl_i_lock_key[depth]); 589b1eaa950SAmir Goldstein #endif 590b1eaa950SAmir Goldstein } 591b1eaa950SAmir Goldstein 5924d314f78SAmir Goldstein static void ovl_next_ino(struct inode *inode) 5934d314f78SAmir Goldstein { 5944d314f78SAmir Goldstein struct ovl_fs *ofs = inode->i_sb->s_fs_info; 5954d314f78SAmir Goldstein 5964d314f78SAmir Goldstein inode->i_ino = atomic_long_inc_return(&ofs->last_ino); 5974d314f78SAmir Goldstein if (unlikely(!inode->i_ino)) 5984d314f78SAmir Goldstein inode->i_ino = atomic_long_inc_return(&ofs->last_ino); 5994d314f78SAmir Goldstein } 6004d314f78SAmir Goldstein 60162c832edSAmir Goldstein static void ovl_map_ino(struct inode *inode, unsigned long ino, int fsid) 602e9be9d5eSMiklos Szeredi { 60312574a9fSAmir Goldstein int xinobits = ovl_xino_bits(inode->i_sb); 604dfe51d47SAmir Goldstein unsigned int xinoshift = 64 - xinobits; 60512574a9fSAmir Goldstein 606695b46e7SAmir Goldstein /* 6076dde1e42SAmir Goldstein * When d_ino is consistent with st_ino (samefs or i_ino has enough 6086dde1e42SAmir Goldstein * bits to encode layer), set the same value used for st_ino to i_ino, 6096dde1e42SAmir Goldstein * so inode number exposed via /proc/locks and a like will be 6106dde1e42SAmir Goldstein * consistent with d_ino and st_ino values. An i_ino value inconsistent 611735c907dSAmir Goldstein * with d_ino also causes nfsd readdirplus to fail. 612695b46e7SAmir Goldstein */ 613695b46e7SAmir Goldstein inode->i_ino = ino; 614dfe51d47SAmir Goldstein if (ovl_same_fs(inode->i_sb)) { 615dfe51d47SAmir Goldstein return; 616dfe51d47SAmir Goldstein } else if (xinobits && likely(!(ino >> xinoshift))) { 617dfe51d47SAmir Goldstein inode->i_ino |= (unsigned long)fsid << (xinoshift + 1); 618dfe51d47SAmir Goldstein return; 619dfe51d47SAmir Goldstein } 620dfe51d47SAmir Goldstein 621dfe51d47SAmir Goldstein /* 622dfe51d47SAmir Goldstein * For directory inodes on non-samefs with xino disabled or xino 623dfe51d47SAmir Goldstein * overflow, we allocate a non-persistent inode number, to be used for 624dfe51d47SAmir Goldstein * resolving st_ino collisions in ovl_map_dev_ino(). 625dfe51d47SAmir Goldstein * 626dfe51d47SAmir Goldstein * To avoid ino collision with legitimate xino values from upper 627dfe51d47SAmir Goldstein * layer (fsid 0), use the lowest xinobit to map the non 628dfe51d47SAmir Goldstein * persistent inode numbers to the unified st_ino address space. 629dfe51d47SAmir Goldstein */ 630dfe51d47SAmir Goldstein if (S_ISDIR(inode->i_mode)) { 6314d314f78SAmir Goldstein ovl_next_ino(inode); 632dfe51d47SAmir Goldstein if (xinobits) { 633dfe51d47SAmir Goldstein inode->i_ino &= ~0UL >> xinobits; 634dfe51d47SAmir Goldstein inode->i_ino |= 1UL << xinoshift; 635dfe51d47SAmir Goldstein } 63612574a9fSAmir Goldstein } 63762c832edSAmir Goldstein } 63862c832edSAmir Goldstein 63962c832edSAmir Goldstein void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, 64062c832edSAmir Goldstein unsigned long ino, int fsid) 64162c832edSAmir Goldstein { 64262c832edSAmir Goldstein struct inode *realinode; 64362c832edSAmir Goldstein 64462c832edSAmir Goldstein if (oip->upperdentry) 64562c832edSAmir Goldstein OVL_I(inode)->__upperdentry = oip->upperdentry; 64662c832edSAmir Goldstein if (oip->lowerpath && oip->lowerpath->dentry) 64762c832edSAmir Goldstein OVL_I(inode)->lower = igrab(d_inode(oip->lowerpath->dentry)); 64862c832edSAmir Goldstein if (oip->lowerdata) 64962c832edSAmir Goldstein OVL_I(inode)->lowerdata = igrab(d_inode(oip->lowerdata)); 65062c832edSAmir Goldstein 65162c832edSAmir Goldstein realinode = ovl_inode_real(inode); 65262c832edSAmir Goldstein ovl_copyattr(realinode, inode); 65362c832edSAmir Goldstein ovl_copyflags(realinode, inode); 65462c832edSAmir Goldstein ovl_map_ino(inode, ino, fsid); 65562c832edSAmir Goldstein } 65662c832edSAmir Goldstein 65762c832edSAmir Goldstein static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev) 65862c832edSAmir Goldstein { 659e9be9d5eSMiklos Szeredi inode->i_mode = mode; 660d719e8f2SMiklos Szeredi inode->i_flags |= S_NOCMTIME; 6612a3a2a3fSMiklos Szeredi #ifdef CONFIG_FS_POSIX_ACL 6622a3a2a3fSMiklos Szeredi inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; 6632a3a2a3fSMiklos Szeredi #endif 664e9be9d5eSMiklos Szeredi 665b1eaa950SAmir Goldstein ovl_lockdep_annotate_inode_mutex_key(inode); 666b1eaa950SAmir Goldstein 667ca4c8a3aSMiklos Szeredi switch (mode & S_IFMT) { 668ca4c8a3aSMiklos Szeredi case S_IFREG: 669ca4c8a3aSMiklos Szeredi inode->i_op = &ovl_file_inode_operations; 670d1d04ef8SMiklos Szeredi inode->i_fop = &ovl_file_operations; 6715b910bd6SAmir Goldstein inode->i_mapping->a_ops = &ovl_aops; 672ca4c8a3aSMiklos Szeredi break; 673ca4c8a3aSMiklos Szeredi 674e9be9d5eSMiklos Szeredi case S_IFDIR: 675e9be9d5eSMiklos Szeredi inode->i_op = &ovl_dir_inode_operations; 676e9be9d5eSMiklos Szeredi inode->i_fop = &ovl_dir_operations; 677e9be9d5eSMiklos Szeredi break; 678e9be9d5eSMiklos Szeredi 679e9be9d5eSMiklos Szeredi case S_IFLNK: 680e9be9d5eSMiklos Szeredi inode->i_op = &ovl_symlink_inode_operations; 681e9be9d5eSMiklos Szeredi break; 682e9be9d5eSMiklos Szeredi 68351f7e52dSMiklos Szeredi default: 6849e142c41SMiklos Szeredi inode->i_op = &ovl_special_inode_operations; 685ca4c8a3aSMiklos Szeredi init_special_inode(inode, mode, rdev); 686e9be9d5eSMiklos Szeredi break; 68751f7e52dSMiklos Szeredi } 68851f7e52dSMiklos Szeredi } 689e9be9d5eSMiklos Szeredi 6905f8415d6SAmir Goldstein /* 6915f8415d6SAmir Goldstein * With inodes index enabled, an overlay inode nlink counts the union of upper 6925f8415d6SAmir Goldstein * hardlinks and non-covered lower hardlinks. During the lifetime of a non-pure 6935f8415d6SAmir Goldstein * upper inode, the following nlink modifying operations can happen: 6945f8415d6SAmir Goldstein * 6955f8415d6SAmir Goldstein * 1. Lower hardlink copy up 6965f8415d6SAmir Goldstein * 2. Upper hardlink created, unlinked or renamed over 6975f8415d6SAmir Goldstein * 3. Lower hardlink whiteout or renamed over 6985f8415d6SAmir Goldstein * 6995f8415d6SAmir Goldstein * For the first, copy up case, the union nlink does not change, whether the 7005f8415d6SAmir Goldstein * operation succeeds or fails, but the upper inode nlink may change. 7015f8415d6SAmir Goldstein * Therefore, before copy up, we store the union nlink value relative to the 7022d2f2d73SMiklos Szeredi * lower inode nlink in the index inode xattr .overlay.nlink. 7035f8415d6SAmir Goldstein * 7045f8415d6SAmir Goldstein * For the second, upper hardlink case, the union nlink should be incremented 7055f8415d6SAmir Goldstein * or decremented IFF the operation succeeds, aligned with nlink change of the 7065f8415d6SAmir Goldstein * upper inode. Therefore, before link/unlink/rename, we store the union nlink 7075f8415d6SAmir Goldstein * value relative to the upper inode nlink in the index inode. 7085f8415d6SAmir Goldstein * 7095f8415d6SAmir Goldstein * For the last, lower cover up case, we simplify things by preceding the 7105f8415d6SAmir Goldstein * whiteout or cover up with copy up. This makes sure that there is an index 7115f8415d6SAmir Goldstein * upper inode where the nlink xattr can be stored before the copied up upper 7125f8415d6SAmir Goldstein * entry is unlink. 7135f8415d6SAmir Goldstein */ 7145f8415d6SAmir Goldstein #define OVL_NLINK_ADD_UPPER (1 << 0) 7155f8415d6SAmir Goldstein 7165f8415d6SAmir Goldstein /* 7175f8415d6SAmir Goldstein * On-disk format for indexed nlink: 7185f8415d6SAmir Goldstein * 7195f8415d6SAmir Goldstein * nlink relative to the upper inode - "U[+-]NUM" 7205f8415d6SAmir Goldstein * nlink relative to the lower inode - "L[+-]NUM" 7215f8415d6SAmir Goldstein */ 7225f8415d6SAmir Goldstein 7235f8415d6SAmir Goldstein static int ovl_set_nlink_common(struct dentry *dentry, 7245f8415d6SAmir Goldstein struct dentry *realdentry, const char *format) 7255f8415d6SAmir Goldstein { 7265f8415d6SAmir Goldstein struct inode *inode = d_inode(dentry); 7275f8415d6SAmir Goldstein struct inode *realinode = d_inode(realdentry); 7285f8415d6SAmir Goldstein char buf[13]; 7295f8415d6SAmir Goldstein int len; 7305f8415d6SAmir Goldstein 7315f8415d6SAmir Goldstein len = snprintf(buf, sizeof(buf), format, 7325f8415d6SAmir Goldstein (int) (inode->i_nlink - realinode->i_nlink)); 7335f8415d6SAmir Goldstein 7346787341aSMiklos Szeredi if (WARN_ON(len >= sizeof(buf))) 7356787341aSMiklos Szeredi return -EIO; 7366787341aSMiklos Szeredi 737610afc0bSMiklos Szeredi return ovl_do_setxattr(OVL_FS(inode->i_sb), ovl_dentry_upper(dentry), 73826150ab5SMiklos Szeredi OVL_XATTR_NLINK, buf, len); 7395f8415d6SAmir Goldstein } 7405f8415d6SAmir Goldstein 7415f8415d6SAmir Goldstein int ovl_set_nlink_upper(struct dentry *dentry) 7425f8415d6SAmir Goldstein { 7435f8415d6SAmir Goldstein return ovl_set_nlink_common(dentry, ovl_dentry_upper(dentry), "U%+i"); 7445f8415d6SAmir Goldstein } 7455f8415d6SAmir Goldstein 7465f8415d6SAmir Goldstein int ovl_set_nlink_lower(struct dentry *dentry) 7475f8415d6SAmir Goldstein { 7485f8415d6SAmir Goldstein return ovl_set_nlink_common(dentry, ovl_dentry_lower(dentry), "L%+i"); 7495f8415d6SAmir Goldstein } 7505f8415d6SAmir Goldstein 751610afc0bSMiklos Szeredi unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, 7525f8415d6SAmir Goldstein struct dentry *upperdentry, 7535f8415d6SAmir Goldstein unsigned int fallback) 7545f8415d6SAmir Goldstein { 7555f8415d6SAmir Goldstein int nlink_diff; 7565f8415d6SAmir Goldstein int nlink; 7575f8415d6SAmir Goldstein char buf[13]; 7585f8415d6SAmir Goldstein int err; 7595f8415d6SAmir Goldstein 7605f8415d6SAmir Goldstein if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1) 7615f8415d6SAmir Goldstein return fallback; 7625f8415d6SAmir Goldstein 763610afc0bSMiklos Szeredi err = ovl_do_getxattr(ofs, upperdentry, OVL_XATTR_NLINK, 764d5dc7486SMiklos Szeredi &buf, sizeof(buf) - 1); 7655f8415d6SAmir Goldstein if (err < 0) 7665f8415d6SAmir Goldstein goto fail; 7675f8415d6SAmir Goldstein 7685f8415d6SAmir Goldstein buf[err] = '\0'; 7695f8415d6SAmir Goldstein if ((buf[0] != 'L' && buf[0] != 'U') || 7705f8415d6SAmir Goldstein (buf[1] != '+' && buf[1] != '-')) 7715f8415d6SAmir Goldstein goto fail; 7725f8415d6SAmir Goldstein 7735f8415d6SAmir Goldstein err = kstrtoint(buf + 1, 10, &nlink_diff); 7745f8415d6SAmir Goldstein if (err < 0) 7755f8415d6SAmir Goldstein goto fail; 7765f8415d6SAmir Goldstein 7775f8415d6SAmir Goldstein nlink = d_inode(buf[0] == 'L' ? lowerdentry : upperdentry)->i_nlink; 7785f8415d6SAmir Goldstein nlink += nlink_diff; 7795f8415d6SAmir Goldstein 7805f8415d6SAmir Goldstein if (nlink <= 0) 7815f8415d6SAmir Goldstein goto fail; 7825f8415d6SAmir Goldstein 7835f8415d6SAmir Goldstein return nlink; 7845f8415d6SAmir Goldstein 7855f8415d6SAmir Goldstein fail: 7861bd0a3aeSlijiazi pr_warn_ratelimited("failed to get index nlink (%pd2, err=%i)\n", 7875f8415d6SAmir Goldstein upperdentry, err); 7885f8415d6SAmir Goldstein return fallback; 7895f8415d6SAmir Goldstein } 7905f8415d6SAmir Goldstein 791ca4c8a3aSMiklos Szeredi struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev) 79251f7e52dSMiklos Szeredi { 79351f7e52dSMiklos Szeredi struct inode *inode; 79451f7e52dSMiklos Szeredi 79551f7e52dSMiklos Szeredi inode = new_inode(sb); 79651f7e52dSMiklos Szeredi if (inode) 79762c832edSAmir Goldstein ovl_fill_inode(inode, mode, rdev); 79851f7e52dSMiklos Szeredi 79951f7e52dSMiklos Szeredi return inode; 80051f7e52dSMiklos Szeredi } 80151f7e52dSMiklos Szeredi 80251f7e52dSMiklos Szeredi static int ovl_inode_test(struct inode *inode, void *data) 80351f7e52dSMiklos Szeredi { 80425b7713aSMiklos Szeredi return inode->i_private == data; 80551f7e52dSMiklos Szeredi } 80651f7e52dSMiklos Szeredi 80751f7e52dSMiklos Szeredi static int ovl_inode_set(struct inode *inode, void *data) 80851f7e52dSMiklos Szeredi { 80925b7713aSMiklos Szeredi inode->i_private = data; 81051f7e52dSMiklos Szeredi return 0; 81151f7e52dSMiklos Szeredi } 81251f7e52dSMiklos Szeredi 813b9ac5c27SMiklos Szeredi static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry, 8144b91c30aSAmir Goldstein struct dentry *upperdentry, bool strict) 815b9ac5c27SMiklos Szeredi { 8164b91c30aSAmir Goldstein /* 8174b91c30aSAmir Goldstein * For directories, @strict verify from lookup path performs consistency 8184b91c30aSAmir Goldstein * checks, so NULL lower/upper in dentry must match NULL lower/upper in 8194b91c30aSAmir Goldstein * inode. Non @strict verify from NFS handle decode path passes NULL for 8204b91c30aSAmir Goldstein * 'unknown' lower/upper. 8214b91c30aSAmir Goldstein */ 8224b91c30aSAmir Goldstein if (S_ISDIR(inode->i_mode) && strict) { 82331747edaSAmir Goldstein /* Real lower dir moved to upper layer under us? */ 82431747edaSAmir Goldstein if (!lowerdentry && ovl_inode_lower(inode)) 82531747edaSAmir Goldstein return false; 82631747edaSAmir Goldstein 82731747edaSAmir Goldstein /* Lookup of an uncovered redirect origin? */ 82831747edaSAmir Goldstein if (!upperdentry && ovl_inode_upper(inode)) 82931747edaSAmir Goldstein return false; 83031747edaSAmir Goldstein } 83131747edaSAmir Goldstein 832939ae4efSAmir Goldstein /* 833939ae4efSAmir Goldstein * Allow non-NULL lower inode in ovl_inode even if lowerdentry is NULL. 834939ae4efSAmir Goldstein * This happens when finding a copied up overlay inode for a renamed 835939ae4efSAmir Goldstein * or hardlinked overlay dentry and lower dentry cannot be followed 836939ae4efSAmir Goldstein * by origin because lower fs does not support file handles. 837939ae4efSAmir Goldstein */ 838939ae4efSAmir Goldstein if (lowerdentry && ovl_inode_lower(inode) != d_inode(lowerdentry)) 839b9ac5c27SMiklos Szeredi return false; 840b9ac5c27SMiklos Szeredi 841b9ac5c27SMiklos Szeredi /* 842b9ac5c27SMiklos Szeredi * Allow non-NULL __upperdentry in inode even if upperdentry is NULL. 843b9ac5c27SMiklos Szeredi * This happens when finding a lower alias for a copied up hard link. 844b9ac5c27SMiklos Szeredi */ 845b9ac5c27SMiklos Szeredi if (upperdentry && ovl_inode_upper(inode) != d_inode(upperdentry)) 846b9ac5c27SMiklos Szeredi return false; 847b9ac5c27SMiklos Szeredi 848b9ac5c27SMiklos Szeredi return true; 849b9ac5c27SMiklos Szeredi } 850b9ac5c27SMiklos Szeredi 8514b91c30aSAmir Goldstein struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, 8524b91c30aSAmir Goldstein bool is_upper) 8539436a1a3SAmir Goldstein { 8544b91c30aSAmir Goldstein struct inode *inode, *key = d_inode(real); 8559436a1a3SAmir Goldstein 8569436a1a3SAmir Goldstein inode = ilookup5(sb, (unsigned long) key, ovl_inode_test, key); 8579436a1a3SAmir Goldstein if (!inode) 8589436a1a3SAmir Goldstein return NULL; 8599436a1a3SAmir Goldstein 8604b91c30aSAmir Goldstein if (!ovl_verify_inode(inode, is_upper ? NULL : real, 8614b91c30aSAmir Goldstein is_upper ? real : NULL, false)) { 8629436a1a3SAmir Goldstein iput(inode); 8639436a1a3SAmir Goldstein return ERR_PTR(-ESTALE); 8649436a1a3SAmir Goldstein } 8659436a1a3SAmir Goldstein 8669436a1a3SAmir Goldstein return inode; 8679436a1a3SAmir Goldstein } 8689436a1a3SAmir Goldstein 869146d62e5SAmir Goldstein bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir) 870146d62e5SAmir Goldstein { 871146d62e5SAmir Goldstein struct inode *key = d_inode(dir); 872146d62e5SAmir Goldstein struct inode *trap; 873146d62e5SAmir Goldstein bool res; 874146d62e5SAmir Goldstein 875146d62e5SAmir Goldstein trap = ilookup5(sb, (unsigned long) key, ovl_inode_test, key); 876146d62e5SAmir Goldstein if (!trap) 877146d62e5SAmir Goldstein return false; 878146d62e5SAmir Goldstein 879146d62e5SAmir Goldstein res = IS_DEADDIR(trap) && !ovl_inode_upper(trap) && 880146d62e5SAmir Goldstein !ovl_inode_lower(trap); 881146d62e5SAmir Goldstein 882146d62e5SAmir Goldstein iput(trap); 883146d62e5SAmir Goldstein return res; 884146d62e5SAmir Goldstein } 885146d62e5SAmir Goldstein 886146d62e5SAmir Goldstein /* 887146d62e5SAmir Goldstein * Create an inode cache entry for layer root dir, that will intentionally 888146d62e5SAmir Goldstein * fail ovl_verify_inode(), so any lookup that will find some layer root 889146d62e5SAmir Goldstein * will fail. 890146d62e5SAmir Goldstein */ 891146d62e5SAmir Goldstein struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir) 892146d62e5SAmir Goldstein { 893146d62e5SAmir Goldstein struct inode *key = d_inode(dir); 894146d62e5SAmir Goldstein struct inode *trap; 895146d62e5SAmir Goldstein 896146d62e5SAmir Goldstein if (!d_is_dir(dir)) 897146d62e5SAmir Goldstein return ERR_PTR(-ENOTDIR); 898146d62e5SAmir Goldstein 899146d62e5SAmir Goldstein trap = iget5_locked(sb, (unsigned long) key, ovl_inode_test, 900146d62e5SAmir Goldstein ovl_inode_set, key); 901146d62e5SAmir Goldstein if (!trap) 902146d62e5SAmir Goldstein return ERR_PTR(-ENOMEM); 903146d62e5SAmir Goldstein 904146d62e5SAmir Goldstein if (!(trap->i_state & I_NEW)) { 905146d62e5SAmir Goldstein /* Conflicting layer roots? */ 906146d62e5SAmir Goldstein iput(trap); 907146d62e5SAmir Goldstein return ERR_PTR(-ELOOP); 908146d62e5SAmir Goldstein } 909146d62e5SAmir Goldstein 910146d62e5SAmir Goldstein trap->i_mode = S_IFDIR; 911146d62e5SAmir Goldstein trap->i_flags = S_DEAD; 912146d62e5SAmir Goldstein unlock_new_inode(trap); 913146d62e5SAmir Goldstein 914146d62e5SAmir Goldstein return trap; 915146d62e5SAmir Goldstein } 916146d62e5SAmir Goldstein 917764baba8SAmir Goldstein /* 918764baba8SAmir Goldstein * Does overlay inode need to be hashed by lower inode? 919764baba8SAmir Goldstein */ 920764baba8SAmir Goldstein static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper, 92174c6e384SMiklos Szeredi struct dentry *lower, bool index) 922764baba8SAmir Goldstein { 923764baba8SAmir Goldstein struct ovl_fs *ofs = sb->s_fs_info; 924764baba8SAmir Goldstein 925764baba8SAmir Goldstein /* No, if pure upper */ 926764baba8SAmir Goldstein if (!lower) 927764baba8SAmir Goldstein return false; 928764baba8SAmir Goldstein 929764baba8SAmir Goldstein /* Yes, if already indexed */ 930764baba8SAmir Goldstein if (index) 931764baba8SAmir Goldstein return true; 932764baba8SAmir Goldstein 933764baba8SAmir Goldstein /* Yes, if won't be copied up */ 93408f4c7c8SMiklos Szeredi if (!ovl_upper_mnt(ofs)) 935764baba8SAmir Goldstein return true; 936764baba8SAmir Goldstein 937764baba8SAmir Goldstein /* No, if lower hardlink is or will be broken on copy up */ 938764baba8SAmir Goldstein if ((upper || !ovl_indexdir(sb)) && 939764baba8SAmir Goldstein !d_is_dir(lower) && d_inode(lower)->i_nlink > 1) 940764baba8SAmir Goldstein return false; 941764baba8SAmir Goldstein 942764baba8SAmir Goldstein /* No, if non-indexed upper with NFS export */ 943764baba8SAmir Goldstein if (sb->s_export_op && upper) 944764baba8SAmir Goldstein return false; 945764baba8SAmir Goldstein 946764baba8SAmir Goldstein /* Otherwise, hash by lower inode for fsnotify */ 947764baba8SAmir Goldstein return true; 948764baba8SAmir Goldstein } 949764baba8SAmir Goldstein 95001b39dccSAmir Goldstein static struct inode *ovl_iget5(struct super_block *sb, struct inode *newinode, 95101b39dccSAmir Goldstein struct inode *key) 95201b39dccSAmir Goldstein { 95301b39dccSAmir Goldstein return newinode ? inode_insert5(newinode, (unsigned long) key, 95401b39dccSAmir Goldstein ovl_inode_test, ovl_inode_set, key) : 95501b39dccSAmir Goldstein iget5_locked(sb, (unsigned long) key, 95601b39dccSAmir Goldstein ovl_inode_test, ovl_inode_set, key); 95701b39dccSAmir Goldstein } 95801b39dccSAmir Goldstein 959ac6a52ebSVivek Goyal struct inode *ovl_get_inode(struct super_block *sb, 960ac6a52ebSVivek Goyal struct ovl_inode_params *oip) 96151f7e52dSMiklos Szeredi { 962610afc0bSMiklos Szeredi struct ovl_fs *ofs = OVL_FS(sb); 963ac6a52ebSVivek Goyal struct dentry *upperdentry = oip->upperdentry; 964ac6a52ebSVivek Goyal struct ovl_path *lowerpath = oip->lowerpath; 96509d8b586SMiklos Szeredi struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL; 96651f7e52dSMiklos Szeredi struct inode *inode; 96712574a9fSAmir Goldstein struct dentry *lowerdentry = lowerpath ? lowerpath->dentry : NULL; 968ac6a52ebSVivek Goyal bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, 969ac6a52ebSVivek Goyal oip->index); 970300b124fSAmir Goldstein int fsid = bylower ? lowerpath->layer->fsid : 0; 97128166ab3SVivek Goyal bool is_dir; 972695b46e7SAmir Goldstein unsigned long ino = 0; 973acf3062aSAmir Goldstein int err = oip->newinode ? -EEXIST : -ENOMEM; 9746eaf0111SAmir Goldstein 97509d8b586SMiklos Szeredi if (!realinode) 97609d8b586SMiklos Szeredi realinode = d_inode(lowerdentry); 97709d8b586SMiklos Szeredi 9786eaf0111SAmir Goldstein /* 979764baba8SAmir Goldstein * Copy up origin (lower) may exist for non-indexed upper, but we must 980764baba8SAmir Goldstein * not use lower as hash key if this is a broken hardlink. 9816eaf0111SAmir Goldstein */ 98231747edaSAmir Goldstein is_dir = S_ISDIR(realinode->i_mode); 983764baba8SAmir Goldstein if (upperdentry || bylower) { 984764baba8SAmir Goldstein struct inode *key = d_inode(bylower ? lowerdentry : 985764baba8SAmir Goldstein upperdentry); 98631747edaSAmir Goldstein unsigned int nlink = is_dir ? 1 : realinode->i_nlink; 987b9ac5c27SMiklos Szeredi 98801b39dccSAmir Goldstein inode = ovl_iget5(sb, oip->newinode, key); 98909d8b586SMiklos Szeredi if (!inode) 990027065b7SVivek Goyal goto out_err; 99109d8b586SMiklos Szeredi if (!(inode->i_state & I_NEW)) { 992b9ac5c27SMiklos Szeredi /* 993b9ac5c27SMiklos Szeredi * Verify that the underlying files stored in the inode 994b9ac5c27SMiklos Szeredi * match those in the dentry. 995b9ac5c27SMiklos Szeredi */ 9964b91c30aSAmir Goldstein if (!ovl_verify_inode(inode, lowerdentry, upperdentry, 9974b91c30aSAmir Goldstein true)) { 998b9ac5c27SMiklos Szeredi iput(inode); 999027065b7SVivek Goyal err = -ESTALE; 1000027065b7SVivek Goyal goto out_err; 1001b9ac5c27SMiklos Szeredi } 1002b9ac5c27SMiklos Szeredi 100309d8b586SMiklos Szeredi dput(upperdentry); 10049cec54c8SVivek Goyal kfree(oip->redirect); 100509d8b586SMiklos Szeredi goto out; 100609d8b586SMiklos Szeredi } 1007e9be9d5eSMiklos Szeredi 100831747edaSAmir Goldstein /* Recalculate nlink for non-dir due to indexing */ 100931747edaSAmir Goldstein if (!is_dir) 1010610afc0bSMiklos Szeredi nlink = ovl_get_nlink(ofs, lowerdentry, upperdentry, 1011610afc0bSMiklos Szeredi nlink); 10125f8415d6SAmir Goldstein set_nlink(inode, nlink); 1013695b46e7SAmir Goldstein ino = key->i_ino; 1014e6d2ebddSMiklos Szeredi } else { 1015764baba8SAmir Goldstein /* Lower hardlink that will be broken on copy up */ 10160aceb53eSAmir Goldstein inode = new_inode(sb); 1017027065b7SVivek Goyal if (!inode) { 1018027065b7SVivek Goyal err = -ENOMEM; 1019027065b7SVivek Goyal goto out_err; 1020027065b7SVivek Goyal } 1021300b124fSAmir Goldstein ino = realinode->i_ino; 1022300b124fSAmir Goldstein fsid = lowerpath->layer->fsid; 1023e6d2ebddSMiklos Szeredi } 102462c832edSAmir Goldstein ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev); 102562c832edSAmir Goldstein ovl_inode_init(inode, oip, ino, fsid); 102613c72075SMiklos Szeredi 1027610afc0bSMiklos Szeredi if (upperdentry && ovl_is_impuredir(sb, upperdentry)) 102813c72075SMiklos Szeredi ovl_set_flag(OVL_IMPURE, inode); 102913c72075SMiklos Szeredi 1030ac6a52ebSVivek Goyal if (oip->index) 10310471a9cdSVivek Goyal ovl_set_flag(OVL_INDEX, inode); 10320471a9cdSVivek Goyal 10339cec54c8SVivek Goyal OVL_I(inode)->redirect = oip->redirect; 10349cec54c8SVivek Goyal 1035a00c2d59SVivek Goyal if (bylower) 1036a00c2d59SVivek Goyal ovl_set_flag(OVL_CONST_INO, inode); 1037a00c2d59SVivek Goyal 1038b79e05aaSAmir Goldstein /* Check for non-merge dir that may have whiteouts */ 103931747edaSAmir Goldstein if (is_dir) { 1040ac6a52ebSVivek Goyal if (((upperdentry && lowerdentry) || oip->numlower > 1) || 1041610afc0bSMiklos Szeredi ovl_check_origin_xattr(ofs, upperdentry ?: lowerdentry)) { 1042b79e05aaSAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, inode); 1043b79e05aaSAmir Goldstein } 1044b79e05aaSAmir Goldstein } 1045b79e05aaSAmir Goldstein 1046e6d2ebddSMiklos Szeredi if (inode->i_state & I_NEW) 1047e6d2ebddSMiklos Szeredi unlock_new_inode(inode); 1048e6d2ebddSMiklos Szeredi out: 1049e9be9d5eSMiklos Szeredi return inode; 1050b9ac5c27SMiklos Szeredi 1051027065b7SVivek Goyal out_err: 10521bd0a3aeSlijiazi pr_warn_ratelimited("failed to get inode (%i)\n", err); 1053027065b7SVivek Goyal inode = ERR_PTR(err); 1054b9ac5c27SMiklos Szeredi goto out; 1055e9be9d5eSMiklos Szeredi } 1056