1e9be9d5eSMiklos Szeredi /* 2e9be9d5eSMiklos Szeredi * 3e9be9d5eSMiklos Szeredi * Copyright (C) 2011 Novell Inc. 4e9be9d5eSMiklos Szeredi * 5e9be9d5eSMiklos Szeredi * This program is free software; you can redistribute it and/or modify it 6e9be9d5eSMiklos Szeredi * under the terms of the GNU General Public License version 2 as published by 7e9be9d5eSMiklos Szeredi * the Free Software Foundation. 8e9be9d5eSMiklos Szeredi */ 9e9be9d5eSMiklos Szeredi 10fb5bb2c3SDavid Howells #include <linux/module.h> 11e9be9d5eSMiklos Szeredi #include <linux/fs.h> 12e9be9d5eSMiklos Szeredi #include <linux/slab.h> 13e9be9d5eSMiklos Szeredi #include <linux/file.h> 14e9be9d5eSMiklos Szeredi #include <linux/splice.h> 15e9be9d5eSMiklos Szeredi #include <linux/xattr.h> 16e9be9d5eSMiklos Szeredi #include <linux/security.h> 17e9be9d5eSMiklos Szeredi #include <linux/uaccess.h> 18174cd4b1SIngo Molnar #include <linux/sched/signal.h> 195b825c3aSIngo Molnar #include <linux/cred.h> 20e9be9d5eSMiklos Szeredi #include <linux/namei.h> 21fb5bb2c3SDavid Howells #include <linux/fdtable.h> 22fb5bb2c3SDavid Howells #include <linux/ratelimit.h> 233a1e819bSAmir Goldstein #include <linux/exportfs.h> 24e9be9d5eSMiklos Szeredi #include "overlayfs.h" 25e9be9d5eSMiklos Szeredi 26e9be9d5eSMiklos Szeredi #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) 27e9be9d5eSMiklos Szeredi 28fb5bb2c3SDavid Howells static bool __read_mostly ovl_check_copy_up; 29fb5bb2c3SDavid Howells module_param_named(check_copy_up, ovl_check_copy_up, bool, 30fb5bb2c3SDavid Howells S_IWUSR | S_IRUGO); 31fb5bb2c3SDavid Howells MODULE_PARM_DESC(ovl_check_copy_up, 32fb5bb2c3SDavid Howells "Warn on copy-up when causing process also has a R/O fd open"); 33fb5bb2c3SDavid Howells 34fb5bb2c3SDavid Howells static int ovl_check_fd(const void *data, struct file *f, unsigned int fd) 35fb5bb2c3SDavid Howells { 36fb5bb2c3SDavid Howells const struct dentry *dentry = data; 37fb5bb2c3SDavid Howells 3845063097SAl Viro if (file_inode(f) == d_inode(dentry)) 39fb5bb2c3SDavid Howells pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n", 40fb5bb2c3SDavid Howells f, fd, current->pid, current->comm); 41fb5bb2c3SDavid Howells return 0; 42fb5bb2c3SDavid Howells } 43fb5bb2c3SDavid Howells 44fb5bb2c3SDavid Howells /* 45fb5bb2c3SDavid Howells * Check the fds open by this process and warn if something like the following 46fb5bb2c3SDavid Howells * scenario is about to occur: 47fb5bb2c3SDavid Howells * 48fb5bb2c3SDavid Howells * fd1 = open("foo", O_RDONLY); 49fb5bb2c3SDavid Howells * fd2 = open("foo", O_RDWR); 50fb5bb2c3SDavid Howells */ 51fb5bb2c3SDavid Howells static void ovl_do_check_copy_up(struct dentry *dentry) 52fb5bb2c3SDavid Howells { 53fb5bb2c3SDavid Howells if (ovl_check_copy_up) 54fb5bb2c3SDavid Howells iterate_fd(current->files, 0, ovl_check_fd, dentry); 55fb5bb2c3SDavid Howells } 56fb5bb2c3SDavid Howells 57e9be9d5eSMiklos Szeredi int ovl_copy_xattr(struct dentry *old, struct dentry *new) 58e9be9d5eSMiklos Szeredi { 59e4ad29faSVito Caputo ssize_t list_size, size, value_size = 0; 60e4ad29faSVito Caputo char *buf, *name, *value = NULL; 61e4ad29faSVito Caputo int uninitialized_var(error); 628b326c61SMiklos Szeredi size_t slen; 63e9be9d5eSMiklos Szeredi 645d6c3191SAndreas Gruenbacher if (!(old->d_inode->i_opflags & IOP_XATTR) || 655d6c3191SAndreas Gruenbacher !(new->d_inode->i_opflags & IOP_XATTR)) 66e9be9d5eSMiklos Szeredi return 0; 67e9be9d5eSMiklos Szeredi 68e9be9d5eSMiklos Szeredi list_size = vfs_listxattr(old, NULL, 0); 69e9be9d5eSMiklos Szeredi if (list_size <= 0) { 70e9be9d5eSMiklos Szeredi if (list_size == -EOPNOTSUPP) 71e9be9d5eSMiklos Szeredi return 0; 72e9be9d5eSMiklos Szeredi return list_size; 73e9be9d5eSMiklos Szeredi } 74e9be9d5eSMiklos Szeredi 75e9be9d5eSMiklos Szeredi buf = kzalloc(list_size, GFP_KERNEL); 76e9be9d5eSMiklos Szeredi if (!buf) 77e9be9d5eSMiklos Szeredi return -ENOMEM; 78e9be9d5eSMiklos Szeredi 79e9be9d5eSMiklos Szeredi list_size = vfs_listxattr(old, buf, list_size); 80e9be9d5eSMiklos Szeredi if (list_size <= 0) { 81e9be9d5eSMiklos Szeredi error = list_size; 82e4ad29faSVito Caputo goto out; 83e9be9d5eSMiklos Szeredi } 84e9be9d5eSMiklos Szeredi 858b326c61SMiklos Szeredi for (name = buf; list_size; name += slen) { 868b326c61SMiklos Szeredi slen = strnlen(name, list_size) + 1; 878b326c61SMiklos Szeredi 888b326c61SMiklos Szeredi /* underlying fs providing us with an broken xattr list? */ 898b326c61SMiklos Szeredi if (WARN_ON(slen > list_size)) { 908b326c61SMiklos Szeredi error = -EIO; 918b326c61SMiklos Szeredi break; 928b326c61SMiklos Szeredi } 938b326c61SMiklos Szeredi list_size -= slen; 948b326c61SMiklos Szeredi 950956254aSMiklos Szeredi if (ovl_is_private_xattr(name)) 960956254aSMiklos Szeredi continue; 97e4ad29faSVito Caputo retry: 98e4ad29faSVito Caputo size = vfs_getxattr(old, name, value, value_size); 99e4ad29faSVito Caputo if (size == -ERANGE) 100e4ad29faSVito Caputo size = vfs_getxattr(old, name, NULL, 0); 101e4ad29faSVito Caputo 10297daf8b9SMiklos Szeredi if (size < 0) { 103e9be9d5eSMiklos Szeredi error = size; 104e4ad29faSVito Caputo break; 105e9be9d5eSMiklos Szeredi } 106e9be9d5eSMiklos Szeredi 107e4ad29faSVito Caputo if (size > value_size) { 108e4ad29faSVito Caputo void *new; 109e4ad29faSVito Caputo 110e4ad29faSVito Caputo new = krealloc(value, size, GFP_KERNEL); 111e4ad29faSVito Caputo if (!new) { 112e4ad29faSVito Caputo error = -ENOMEM; 113e4ad29faSVito Caputo break; 114e4ad29faSVito Caputo } 115e4ad29faSVito Caputo value = new; 116e4ad29faSVito Caputo value_size = size; 117e4ad29faSVito Caputo goto retry; 118e4ad29faSVito Caputo } 119e4ad29faSVito Caputo 120121ab822SVivek Goyal error = security_inode_copy_up_xattr(name); 121121ab822SVivek Goyal if (error < 0 && error != -EOPNOTSUPP) 122121ab822SVivek Goyal break; 123121ab822SVivek Goyal if (error == 1) { 124121ab822SVivek Goyal error = 0; 125121ab822SVivek Goyal continue; /* Discard */ 126121ab822SVivek Goyal } 127e4ad29faSVito Caputo error = vfs_setxattr(new, name, value, size, 0); 128e4ad29faSVito Caputo if (error) 129e4ad29faSVito Caputo break; 130e4ad29faSVito Caputo } 131e9be9d5eSMiklos Szeredi kfree(value); 132e9be9d5eSMiklos Szeredi out: 133e9be9d5eSMiklos Szeredi kfree(buf); 134e9be9d5eSMiklos Szeredi return error; 135e9be9d5eSMiklos Szeredi } 136e9be9d5eSMiklos Szeredi 137e9be9d5eSMiklos Szeredi static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) 138e9be9d5eSMiklos Szeredi { 139e9be9d5eSMiklos Szeredi struct file *old_file; 140e9be9d5eSMiklos Szeredi struct file *new_file; 141e9be9d5eSMiklos Szeredi loff_t old_pos = 0; 142e9be9d5eSMiklos Szeredi loff_t new_pos = 0; 143e9be9d5eSMiklos Szeredi int error = 0; 144e9be9d5eSMiklos Szeredi 145e9be9d5eSMiklos Szeredi if (len == 0) 146e9be9d5eSMiklos Szeredi return 0; 147e9be9d5eSMiklos Szeredi 1480480334fSDavid Howells old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); 149e9be9d5eSMiklos Szeredi if (IS_ERR(old_file)) 150e9be9d5eSMiklos Szeredi return PTR_ERR(old_file); 151e9be9d5eSMiklos Szeredi 1520480334fSDavid Howells new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); 153e9be9d5eSMiklos Szeredi if (IS_ERR(new_file)) { 154e9be9d5eSMiklos Szeredi error = PTR_ERR(new_file); 155e9be9d5eSMiklos Szeredi goto out_fput; 156e9be9d5eSMiklos Szeredi } 157e9be9d5eSMiklos Szeredi 1582ea98466SAmir Goldstein /* Try to use clone_file_range to clone up within the same fs */ 1592ea98466SAmir Goldstein error = vfs_clone_file_range(old_file, 0, new_file, 0, len); 1602ea98466SAmir Goldstein if (!error) 1612ea98466SAmir Goldstein goto out; 1622ea98466SAmir Goldstein /* Couldn't clone, so now we try to copy the data */ 1632ea98466SAmir Goldstein error = 0; 1642ea98466SAmir Goldstein 165e9be9d5eSMiklos Szeredi /* FIXME: copy up sparse files efficiently */ 166e9be9d5eSMiklos Szeredi while (len) { 167e9be9d5eSMiklos Szeredi size_t this_len = OVL_COPY_UP_CHUNK_SIZE; 168e9be9d5eSMiklos Szeredi long bytes; 169e9be9d5eSMiklos Szeredi 170e9be9d5eSMiklos Szeredi if (len < this_len) 171e9be9d5eSMiklos Szeredi this_len = len; 172e9be9d5eSMiklos Szeredi 173e9be9d5eSMiklos Szeredi if (signal_pending_state(TASK_KILLABLE, current)) { 174e9be9d5eSMiklos Szeredi error = -EINTR; 175e9be9d5eSMiklos Szeredi break; 176e9be9d5eSMiklos Szeredi } 177e9be9d5eSMiklos Szeredi 178e9be9d5eSMiklos Szeredi bytes = do_splice_direct(old_file, &old_pos, 179e9be9d5eSMiklos Szeredi new_file, &new_pos, 180e9be9d5eSMiklos Szeredi this_len, SPLICE_F_MOVE); 181e9be9d5eSMiklos Szeredi if (bytes <= 0) { 182e9be9d5eSMiklos Szeredi error = bytes; 183e9be9d5eSMiklos Szeredi break; 184e9be9d5eSMiklos Szeredi } 185e9be9d5eSMiklos Szeredi WARN_ON(old_pos != new_pos); 186e9be9d5eSMiklos Szeredi 187e9be9d5eSMiklos Szeredi len -= bytes; 188e9be9d5eSMiklos Szeredi } 1892ea98466SAmir Goldstein out: 190641089c1SMiklos Szeredi if (!error) 191641089c1SMiklos Szeredi error = vfs_fsync(new_file, 0); 192e9be9d5eSMiklos Szeredi fput(new_file); 193e9be9d5eSMiklos Szeredi out_fput: 194e9be9d5eSMiklos Szeredi fput(old_file); 195e9be9d5eSMiklos Szeredi return error; 196e9be9d5eSMiklos Szeredi } 197e9be9d5eSMiklos Szeredi 198e9be9d5eSMiklos Szeredi static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) 199e9be9d5eSMiklos Szeredi { 200e9be9d5eSMiklos Szeredi struct iattr attr = { 201e9be9d5eSMiklos Szeredi .ia_valid = 202e9be9d5eSMiklos Szeredi ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, 203e9be9d5eSMiklos Szeredi .ia_atime = stat->atime, 204e9be9d5eSMiklos Szeredi .ia_mtime = stat->mtime, 205e9be9d5eSMiklos Szeredi }; 206e9be9d5eSMiklos Szeredi 207e9be9d5eSMiklos Szeredi return notify_change(upperdentry, &attr, NULL); 208e9be9d5eSMiklos Szeredi } 209e9be9d5eSMiklos Szeredi 210e9be9d5eSMiklos Szeredi int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) 211e9be9d5eSMiklos Szeredi { 212e9be9d5eSMiklos Szeredi int err = 0; 213e9be9d5eSMiklos Szeredi 214e9be9d5eSMiklos Szeredi if (!S_ISLNK(stat->mode)) { 215e9be9d5eSMiklos Szeredi struct iattr attr = { 216e9be9d5eSMiklos Szeredi .ia_valid = ATTR_MODE, 217e9be9d5eSMiklos Szeredi .ia_mode = stat->mode, 218e9be9d5eSMiklos Szeredi }; 219e9be9d5eSMiklos Szeredi err = notify_change(upperdentry, &attr, NULL); 220e9be9d5eSMiklos Szeredi } 221e9be9d5eSMiklos Szeredi if (!err) { 222e9be9d5eSMiklos Szeredi struct iattr attr = { 223e9be9d5eSMiklos Szeredi .ia_valid = ATTR_UID | ATTR_GID, 224e9be9d5eSMiklos Szeredi .ia_uid = stat->uid, 225e9be9d5eSMiklos Szeredi .ia_gid = stat->gid, 226e9be9d5eSMiklos Szeredi }; 227e9be9d5eSMiklos Szeredi err = notify_change(upperdentry, &attr, NULL); 228e9be9d5eSMiklos Szeredi } 229e9be9d5eSMiklos Szeredi if (!err) 230e9be9d5eSMiklos Szeredi ovl_set_timestamps(upperdentry, stat); 231e9be9d5eSMiklos Szeredi 232e9be9d5eSMiklos Szeredi return err; 233e9be9d5eSMiklos Szeredi } 234e9be9d5eSMiklos Szeredi 23505122443SAmir Goldstein struct ovl_fh *ovl_encode_fh(struct dentry *real, bool is_upper) 2363a1e819bSAmir Goldstein { 2373a1e819bSAmir Goldstein struct ovl_fh *fh; 2383a1e819bSAmir Goldstein int fh_type, fh_len, dwords; 2393a1e819bSAmir Goldstein void *buf; 2403a1e819bSAmir Goldstein int buflen = MAX_HANDLE_SZ; 24105122443SAmir Goldstein uuid_t *uuid = &real->d_sb->s_uuid; 2423a1e819bSAmir Goldstein 2430ee931c4SMichal Hocko buf = kmalloc(buflen, GFP_KERNEL); 2443a1e819bSAmir Goldstein if (!buf) 2453a1e819bSAmir Goldstein return ERR_PTR(-ENOMEM); 2463a1e819bSAmir Goldstein 2473a1e819bSAmir Goldstein /* 2483a1e819bSAmir Goldstein * We encode a non-connectable file handle for non-dir, because we 2493a1e819bSAmir Goldstein * only need to find the lower inode number and we don't want to pay 2503a1e819bSAmir Goldstein * the price or reconnecting the dentry. 2513a1e819bSAmir Goldstein */ 2523a1e819bSAmir Goldstein dwords = buflen >> 2; 25305122443SAmir Goldstein fh_type = exportfs_encode_fh(real, buf, &dwords, 0); 2543a1e819bSAmir Goldstein buflen = (dwords << 2); 2553a1e819bSAmir Goldstein 2563a1e819bSAmir Goldstein fh = ERR_PTR(-EIO); 2573a1e819bSAmir Goldstein if (WARN_ON(fh_type < 0) || 2583a1e819bSAmir Goldstein WARN_ON(buflen > MAX_HANDLE_SZ) || 2593a1e819bSAmir Goldstein WARN_ON(fh_type == FILEID_INVALID)) 2603a1e819bSAmir Goldstein goto out; 2613a1e819bSAmir Goldstein 2623a1e819bSAmir Goldstein BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255); 2633a1e819bSAmir Goldstein fh_len = offsetof(struct ovl_fh, fid) + buflen; 2643a1e819bSAmir Goldstein fh = kmalloc(fh_len, GFP_KERNEL); 2653a1e819bSAmir Goldstein if (!fh) { 2663a1e819bSAmir Goldstein fh = ERR_PTR(-ENOMEM); 2673a1e819bSAmir Goldstein goto out; 2683a1e819bSAmir Goldstein } 2693a1e819bSAmir Goldstein 2703a1e819bSAmir Goldstein fh->version = OVL_FH_VERSION; 2713a1e819bSAmir Goldstein fh->magic = OVL_FH_MAGIC; 2723a1e819bSAmir Goldstein fh->type = fh_type; 2733a1e819bSAmir Goldstein fh->flags = OVL_FH_FLAG_CPU_ENDIAN; 27454fb347eSAmir Goldstein /* 27554fb347eSAmir Goldstein * When we will want to decode an overlay dentry from this handle 27654fb347eSAmir Goldstein * and all layers are on the same fs, if we get a disconncted real 27754fb347eSAmir Goldstein * dentry when we decode fid, the only way to tell if we should assign 27854fb347eSAmir Goldstein * it to upperdentry or to lowerstack is by checking this flag. 27954fb347eSAmir Goldstein */ 28054fb347eSAmir Goldstein if (is_upper) 28154fb347eSAmir Goldstein fh->flags |= OVL_FH_FLAG_PATH_UPPER; 2823a1e819bSAmir Goldstein fh->len = fh_len; 2833a1e819bSAmir Goldstein fh->uuid = *uuid; 2843a1e819bSAmir Goldstein memcpy(fh->fid, buf, buflen); 2853a1e819bSAmir Goldstein 2863a1e819bSAmir Goldstein out: 2873a1e819bSAmir Goldstein kfree(buf); 2883a1e819bSAmir Goldstein return fh; 2893a1e819bSAmir Goldstein } 2903a1e819bSAmir Goldstein 2919678e630SAmir Goldstein int ovl_set_origin(struct dentry *dentry, struct dentry *lower, 2923a1e819bSAmir Goldstein struct dentry *upper) 2933a1e819bSAmir Goldstein { 2943a1e819bSAmir Goldstein const struct ovl_fh *fh = NULL; 2953a1e819bSAmir Goldstein int err; 2963a1e819bSAmir Goldstein 2973a1e819bSAmir Goldstein /* 2983a1e819bSAmir Goldstein * When lower layer doesn't support export operations store a 'null' fh, 2993a1e819bSAmir Goldstein * so we can use the overlay.origin xattr to distignuish between a copy 3003a1e819bSAmir Goldstein * up and a pure upper inode. 3013a1e819bSAmir Goldstein */ 30202bcd157SAmir Goldstein if (ovl_can_decode_fh(lower->d_sb)) { 30354fb347eSAmir Goldstein fh = ovl_encode_fh(lower, false); 3043a1e819bSAmir Goldstein if (IS_ERR(fh)) 3053a1e819bSAmir Goldstein return PTR_ERR(fh); 3063a1e819bSAmir Goldstein } 3073a1e819bSAmir Goldstein 3086266d465SMiklos Szeredi /* 3096266d465SMiklos Szeredi * Do not fail when upper doesn't support xattrs. 3106266d465SMiklos Szeredi */ 3116266d465SMiklos Szeredi err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh, 3126266d465SMiklos Szeredi fh ? fh->len : 0, 0); 3133a1e819bSAmir Goldstein kfree(fh); 3143a1e819bSAmir Goldstein 3153a1e819bSAmir Goldstein return err; 3163a1e819bSAmir Goldstein } 3173a1e819bSAmir Goldstein 318016b720fSAmir Goldstein /* Store file handle of @upper dir in @index dir entry */ 319016b720fSAmir Goldstein static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index) 320016b720fSAmir Goldstein { 321016b720fSAmir Goldstein const struct ovl_fh *fh; 322016b720fSAmir Goldstein int err; 323016b720fSAmir Goldstein 324016b720fSAmir Goldstein fh = ovl_encode_fh(upper, true); 325016b720fSAmir Goldstein if (IS_ERR(fh)) 326016b720fSAmir Goldstein return PTR_ERR(fh); 327016b720fSAmir Goldstein 328016b720fSAmir Goldstein err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh, fh->len, 0); 329016b720fSAmir Goldstein 330016b720fSAmir Goldstein kfree(fh); 331016b720fSAmir Goldstein return err; 332016b720fSAmir Goldstein } 333016b720fSAmir Goldstein 334016b720fSAmir Goldstein /* 335016b720fSAmir Goldstein * Create and install index entry. 336016b720fSAmir Goldstein * 337016b720fSAmir Goldstein * Caller must hold i_mutex on indexdir. 338016b720fSAmir Goldstein */ 339016b720fSAmir Goldstein static int ovl_create_index(struct dentry *dentry, struct dentry *origin, 340016b720fSAmir Goldstein struct dentry *upper) 341016b720fSAmir Goldstein { 342016b720fSAmir Goldstein struct dentry *indexdir = ovl_indexdir(dentry->d_sb); 343016b720fSAmir Goldstein struct inode *dir = d_inode(indexdir); 344016b720fSAmir Goldstein struct dentry *index = NULL; 345016b720fSAmir Goldstein struct dentry *temp = NULL; 346016b720fSAmir Goldstein struct qstr name = { }; 347016b720fSAmir Goldstein int err; 348016b720fSAmir Goldstein 349016b720fSAmir Goldstein /* 350016b720fSAmir Goldstein * For now this is only used for creating index entry for directories, 351016b720fSAmir Goldstein * because non-dir are copied up directly to index and then hardlinked 352016b720fSAmir Goldstein * to upper dir. 353016b720fSAmir Goldstein * 354016b720fSAmir Goldstein * TODO: implement create index for non-dir, so we can call it when 355016b720fSAmir Goldstein * encoding file handle for non-dir in case index does not exist. 356016b720fSAmir Goldstein */ 357016b720fSAmir Goldstein if (WARN_ON(!d_is_dir(dentry))) 358016b720fSAmir Goldstein return -EIO; 359016b720fSAmir Goldstein 360016b720fSAmir Goldstein /* Directory not expected to be indexed before copy up */ 361016b720fSAmir Goldstein if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry)))) 362016b720fSAmir Goldstein return -EIO; 363016b720fSAmir Goldstein 364016b720fSAmir Goldstein err = ovl_get_index_name(origin, &name); 365016b720fSAmir Goldstein if (err) 366016b720fSAmir Goldstein return err; 367016b720fSAmir Goldstein 368016b720fSAmir Goldstein temp = ovl_lookup_temp(indexdir); 369016b720fSAmir Goldstein if (IS_ERR(temp)) 370016b720fSAmir Goldstein goto temp_err; 371016b720fSAmir Goldstein 372016b720fSAmir Goldstein err = ovl_do_mkdir(dir, temp, S_IFDIR, true); 373016b720fSAmir Goldstein if (err) 374016b720fSAmir Goldstein goto out; 375016b720fSAmir Goldstein 376016b720fSAmir Goldstein err = ovl_set_upper_fh(upper, temp); 377016b720fSAmir Goldstein if (err) 378016b720fSAmir Goldstein goto out_cleanup; 379016b720fSAmir Goldstein 380016b720fSAmir Goldstein index = lookup_one_len(name.name, indexdir, name.len); 381016b720fSAmir Goldstein if (IS_ERR(index)) { 382016b720fSAmir Goldstein err = PTR_ERR(index); 383016b720fSAmir Goldstein } else { 384016b720fSAmir Goldstein err = ovl_do_rename(dir, temp, dir, index, 0); 385016b720fSAmir Goldstein dput(index); 386016b720fSAmir Goldstein } 387016b720fSAmir Goldstein 388016b720fSAmir Goldstein if (err) 389016b720fSAmir Goldstein goto out_cleanup; 390016b720fSAmir Goldstein 391016b720fSAmir Goldstein out: 392016b720fSAmir Goldstein dput(temp); 393016b720fSAmir Goldstein kfree(name.name); 394016b720fSAmir Goldstein return err; 395016b720fSAmir Goldstein 396016b720fSAmir Goldstein temp_err: 397016b720fSAmir Goldstein err = PTR_ERR(temp); 398016b720fSAmir Goldstein temp = NULL; 399016b720fSAmir Goldstein goto out; 400016b720fSAmir Goldstein 401016b720fSAmir Goldstein out_cleanup: 402016b720fSAmir Goldstein ovl_cleanup(dir, temp); 403016b720fSAmir Goldstein goto out; 404016b720fSAmir Goldstein } 405016b720fSAmir Goldstein 40623f0ab13SMiklos Szeredi struct ovl_copy_up_ctx { 407a6fb235aSMiklos Szeredi struct dentry *parent; 40823f0ab13SMiklos Szeredi struct dentry *dentry; 40923f0ab13SMiklos Szeredi struct path lowerpath; 41023f0ab13SMiklos Szeredi struct kstat stat; 41123f0ab13SMiklos Szeredi struct kstat pstat; 41223f0ab13SMiklos Szeredi const char *link; 41359be0971SAmir Goldstein struct dentry *destdir; 41459be0971SAmir Goldstein struct qstr destname; 41523f0ab13SMiklos Szeredi struct dentry *workdir; 41623f0ab13SMiklos Szeredi bool tmpfile; 41759be0971SAmir Goldstein bool origin; 418016b720fSAmir Goldstein bool indexed; 41923f0ab13SMiklos Szeredi }; 42023f0ab13SMiklos Szeredi 421f4439de1SAmir Goldstein static int ovl_link_up(struct ovl_copy_up_ctx *c) 422f4439de1SAmir Goldstein { 423f4439de1SAmir Goldstein int err; 424f4439de1SAmir Goldstein struct dentry *upper; 425f4439de1SAmir Goldstein struct dentry *upperdir = ovl_dentry_upper(c->parent); 426f4439de1SAmir Goldstein struct inode *udir = d_inode(upperdir); 427f4439de1SAmir Goldstein 428f4439de1SAmir Goldstein /* Mark parent "impure" because it may now contain non-pure upper */ 429f4439de1SAmir Goldstein err = ovl_set_impure(c->parent, upperdir); 430f4439de1SAmir Goldstein if (err) 431f4439de1SAmir Goldstein return err; 432f4439de1SAmir Goldstein 433f4439de1SAmir Goldstein err = ovl_set_nlink_lower(c->dentry); 434f4439de1SAmir Goldstein if (err) 435f4439de1SAmir Goldstein return err; 436f4439de1SAmir Goldstein 437f4439de1SAmir Goldstein inode_lock_nested(udir, I_MUTEX_PARENT); 438f4439de1SAmir Goldstein upper = lookup_one_len(c->dentry->d_name.name, upperdir, 439f4439de1SAmir Goldstein c->dentry->d_name.len); 440f4439de1SAmir Goldstein err = PTR_ERR(upper); 441f4439de1SAmir Goldstein if (!IS_ERR(upper)) { 442f4439de1SAmir Goldstein err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper, 443f4439de1SAmir Goldstein true); 444f4439de1SAmir Goldstein dput(upper); 445f4439de1SAmir Goldstein 446f4439de1SAmir Goldstein if (!err) { 447f4439de1SAmir Goldstein /* Restore timestamps on parent (best effort) */ 448f4439de1SAmir Goldstein ovl_set_timestamps(upperdir, &c->pstat); 449f4439de1SAmir Goldstein ovl_dentry_set_upper_alias(c->dentry); 450f4439de1SAmir Goldstein } 451f4439de1SAmir Goldstein } 452f4439de1SAmir Goldstein inode_unlock(udir); 453f4439de1SAmir Goldstein ovl_set_nlink_upper(c->dentry); 454f4439de1SAmir Goldstein 455f4439de1SAmir Goldstein return err; 456f4439de1SAmir Goldstein } 457f4439de1SAmir Goldstein 45823f0ab13SMiklos Szeredi static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp, 45923f0ab13SMiklos Szeredi struct dentry **newdentry) 46015932c41SAmir Goldstein { 46115932c41SAmir Goldstein int err; 46215932c41SAmir Goldstein struct dentry *upper; 46359be0971SAmir Goldstein struct inode *udir = d_inode(c->destdir); 46415932c41SAmir Goldstein 46559be0971SAmir Goldstein upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len); 46615932c41SAmir Goldstein if (IS_ERR(upper)) 46715932c41SAmir Goldstein return PTR_ERR(upper); 46815932c41SAmir Goldstein 46923f0ab13SMiklos Szeredi if (c->tmpfile) 47015932c41SAmir Goldstein err = ovl_do_link(temp, udir, upper, true); 47115932c41SAmir Goldstein else 47223f0ab13SMiklos Szeredi err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0); 47315932c41SAmir Goldstein 47459be0971SAmir Goldstein if (!err) 47523f0ab13SMiklos Szeredi *newdentry = dget(c->tmpfile ? upper : temp); 47615932c41SAmir Goldstein dput(upper); 47715932c41SAmir Goldstein 47815932c41SAmir Goldstein return err; 47915932c41SAmir Goldstein } 48015932c41SAmir Goldstein 48123f0ab13SMiklos Szeredi static int ovl_get_tmpfile(struct ovl_copy_up_ctx *c, struct dentry **tempp) 482e9be9d5eSMiklos Szeredi { 483e9be9d5eSMiklos Szeredi int err; 4847d90b853SMiklos Szeredi struct dentry *temp; 485d8ad8b49SVivek Goyal const struct cred *old_creds = NULL; 486d8ad8b49SVivek Goyal struct cred *new_creds = NULL; 48732a3d848SAl Viro struct cattr cattr = { 48832a3d848SAl Viro /* Can't properly set mode on creation because of the umask */ 48923f0ab13SMiklos Szeredi .mode = c->stat.mode & S_IFMT, 49023f0ab13SMiklos Szeredi .rdev = c->stat.rdev, 49123f0ab13SMiklos Szeredi .link = c->link 49232a3d848SAl Viro }; 493e9be9d5eSMiklos Szeredi 49423f0ab13SMiklos Szeredi err = security_inode_copy_up(c->dentry, &new_creds); 495d8ad8b49SVivek Goyal if (err < 0) 496e85f82ffSMiklos Szeredi goto out; 497d8ad8b49SVivek Goyal 498d8ad8b49SVivek Goyal if (new_creds) 499d8ad8b49SVivek Goyal old_creds = override_creds(new_creds); 500d8ad8b49SVivek Goyal 50123f0ab13SMiklos Szeredi if (c->tmpfile) { 50223f0ab13SMiklos Szeredi temp = ovl_do_tmpfile(c->workdir, c->stat.mode); 5037d90b853SMiklos Szeredi if (IS_ERR(temp)) 5047d90b853SMiklos Szeredi goto temp_err; 5057d90b853SMiklos Szeredi } else { 50623f0ab13SMiklos Szeredi temp = ovl_lookup_temp(c->workdir); 5077d90b853SMiklos Szeredi if (IS_ERR(temp)) 5087d90b853SMiklos Szeredi goto temp_err; 5097d90b853SMiklos Szeredi 51023f0ab13SMiklos Szeredi err = ovl_create_real(d_inode(c->workdir), temp, &cattr, 5117d90b853SMiklos Szeredi NULL, true); 5127d90b853SMiklos Szeredi if (err) { 5137d90b853SMiklos Szeredi dput(temp); 5147d90b853SMiklos Szeredi goto out; 5158137ae26SAmir Goldstein } 5167d90b853SMiklos Szeredi } 5177d90b853SMiklos Szeredi err = 0; 5187d90b853SMiklos Szeredi *tempp = temp; 5197d90b853SMiklos Szeredi out: 520d8ad8b49SVivek Goyal if (new_creds) { 521d8ad8b49SVivek Goyal revert_creds(old_creds); 522d8ad8b49SVivek Goyal put_cred(new_creds); 523d8ad8b49SVivek Goyal } 524d8ad8b49SVivek Goyal 5257d90b853SMiklos Szeredi return err; 5267d90b853SMiklos Szeredi 5277d90b853SMiklos Szeredi temp_err: 5287d90b853SMiklos Szeredi err = PTR_ERR(temp); 5297d90b853SMiklos Szeredi goto out; 5307d90b853SMiklos Szeredi } 5317d90b853SMiklos Szeredi 53223f0ab13SMiklos Szeredi static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp) 53302209d10SAmir Goldstein { 53402209d10SAmir Goldstein int err; 53502209d10SAmir Goldstein 53623f0ab13SMiklos Szeredi if (S_ISREG(c->stat.mode)) { 53702209d10SAmir Goldstein struct path upperpath; 53802209d10SAmir Goldstein 53923f0ab13SMiklos Szeredi ovl_path_upper(c->dentry, &upperpath); 54002209d10SAmir Goldstein BUG_ON(upperpath.dentry != NULL); 54102209d10SAmir Goldstein upperpath.dentry = temp; 54202209d10SAmir Goldstein 54323f0ab13SMiklos Szeredi err = ovl_copy_up_data(&c->lowerpath, &upperpath, c->stat.size); 54402209d10SAmir Goldstein if (err) 54502209d10SAmir Goldstein return err; 54602209d10SAmir Goldstein } 54702209d10SAmir Goldstein 54823f0ab13SMiklos Szeredi err = ovl_copy_xattr(c->lowerpath.dentry, temp); 54902209d10SAmir Goldstein if (err) 55002209d10SAmir Goldstein return err; 55102209d10SAmir Goldstein 55202209d10SAmir Goldstein inode_lock(temp->d_inode); 55323f0ab13SMiklos Szeredi err = ovl_set_attr(temp, &c->stat); 55402209d10SAmir Goldstein inode_unlock(temp->d_inode); 55502209d10SAmir Goldstein if (err) 55602209d10SAmir Goldstein return err; 55702209d10SAmir Goldstein 55802209d10SAmir Goldstein /* 55902209d10SAmir Goldstein * Store identifier of lower inode in upper inode xattr to 56002209d10SAmir Goldstein * allow lookup of the copy up origin inode. 56102209d10SAmir Goldstein * 56202209d10SAmir Goldstein * Don't set origin when we are breaking the association with a lower 56302209d10SAmir Goldstein * hard link. 56402209d10SAmir Goldstein */ 56559be0971SAmir Goldstein if (c->origin) { 56623f0ab13SMiklos Szeredi err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp); 56702209d10SAmir Goldstein if (err) 56802209d10SAmir Goldstein return err; 56902209d10SAmir Goldstein } 57002209d10SAmir Goldstein 57102209d10SAmir Goldstein return 0; 57202209d10SAmir Goldstein } 57302209d10SAmir Goldstein 57423f0ab13SMiklos Szeredi static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c) 5757d90b853SMiklos Szeredi { 57659be0971SAmir Goldstein struct inode *udir = c->destdir->d_inode; 577b79e05aaSAmir Goldstein struct inode *inode; 5787d90b853SMiklos Szeredi struct dentry *newdentry = NULL; 5797d90b853SMiklos Szeredi struct dentry *temp = NULL; 5807d90b853SMiklos Szeredi int err; 5817d90b853SMiklos Szeredi 58223f0ab13SMiklos Szeredi err = ovl_get_tmpfile(c, &temp); 583e9be9d5eSMiklos Szeredi if (err) 584e85f82ffSMiklos Szeredi goto out; 585e9be9d5eSMiklos Szeredi 58623f0ab13SMiklos Szeredi err = ovl_copy_up_inode(c, temp); 587e9be9d5eSMiklos Szeredi if (err) 588e9be9d5eSMiklos Szeredi goto out_cleanup; 5893a1e819bSAmir Goldstein 590016b720fSAmir Goldstein if (S_ISDIR(c->stat.mode) && c->indexed) { 591016b720fSAmir Goldstein err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp); 592016b720fSAmir Goldstein if (err) 593016b720fSAmir Goldstein goto out_cleanup; 594016b720fSAmir Goldstein } 595016b720fSAmir Goldstein 59623f0ab13SMiklos Szeredi if (c->tmpfile) { 59715932c41SAmir Goldstein inode_lock_nested(udir, I_MUTEX_PARENT); 59823f0ab13SMiklos Szeredi err = ovl_install_temp(c, temp, &newdentry); 59915932c41SAmir Goldstein inode_unlock(udir); 60015932c41SAmir Goldstein } else { 60123f0ab13SMiklos Szeredi err = ovl_install_temp(c, temp, &newdentry); 602e85f82ffSMiklos Szeredi } 603e9be9d5eSMiklos Szeredi if (err) 604e9be9d5eSMiklos Szeredi goto out_cleanup; 605e9be9d5eSMiklos Szeredi 606b79e05aaSAmir Goldstein inode = d_inode(c->dentry); 607b79e05aaSAmir Goldstein ovl_inode_update(inode, newdentry); 608b79e05aaSAmir Goldstein if (S_ISDIR(inode->i_mode)) 609b79e05aaSAmir Goldstein ovl_set_flag(OVL_WHITEOUTS, inode); 610b79e05aaSAmir Goldstein 611e9be9d5eSMiklos Szeredi out: 612e85f82ffSMiklos Szeredi dput(temp); 613e9be9d5eSMiklos Szeredi return err; 614e9be9d5eSMiklos Szeredi 615e9be9d5eSMiklos Szeredi out_cleanup: 61623f0ab13SMiklos Szeredi if (!c->tmpfile) 61723f0ab13SMiklos Szeredi ovl_cleanup(d_inode(c->workdir), temp); 618e85f82ffSMiklos Szeredi goto out; 619e9be9d5eSMiklos Szeredi } 620e9be9d5eSMiklos Szeredi 621e9be9d5eSMiklos Szeredi /* 622e9be9d5eSMiklos Szeredi * Copy up a single dentry 623e9be9d5eSMiklos Szeredi * 624a6c60655SMiklos Szeredi * All renames start with copy up of source if necessary. The actual 625a6c60655SMiklos Szeredi * rename will only proceed once the copy up was successful. Copy up uses 626a6c60655SMiklos Szeredi * upper parent i_mutex for exclusion. Since rename can change d_parent it 627a6c60655SMiklos Szeredi * is possible that the copy up will lock the old parent. At that point 628a6c60655SMiklos Szeredi * the file will have already been copied up anyway. 629e9be9d5eSMiklos Szeredi */ 630a6fb235aSMiklos Szeredi static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) 631e9be9d5eSMiklos Szeredi { 632e9be9d5eSMiklos Szeredi int err; 63323f0ab13SMiklos Szeredi struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info; 634016b720fSAmir Goldstein bool to_index = false; 63559be0971SAmir Goldstein 636016b720fSAmir Goldstein /* 637016b720fSAmir Goldstein * Indexed non-dir is copied up directly to the index entry and then 638016b720fSAmir Goldstein * hardlinked to upper dir. Indexed dir is copied up to indexdir, 639016b720fSAmir Goldstein * then index entry is created and then copied up dir installed. 640016b720fSAmir Goldstein * Copying dir up to indexdir instead of workdir simplifies locking. 641016b720fSAmir Goldstein */ 642016b720fSAmir Goldstein if (ovl_need_index(c->dentry)) { 643016b720fSAmir Goldstein c->indexed = true; 644016b720fSAmir Goldstein if (S_ISDIR(c->stat.mode)) 645016b720fSAmir Goldstein c->workdir = ovl_indexdir(c->dentry->d_sb); 646016b720fSAmir Goldstein else 647016b720fSAmir Goldstein to_index = true; 648016b720fSAmir Goldstein } 649016b720fSAmir Goldstein 650016b720fSAmir Goldstein if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index) 65159be0971SAmir Goldstein c->origin = true; 65259be0971SAmir Goldstein 653016b720fSAmir Goldstein if (to_index) { 65459be0971SAmir Goldstein c->destdir = ovl_indexdir(c->dentry->d_sb); 65559be0971SAmir Goldstein err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); 656f3a15685SAmir Goldstein if (err) 657f3a15685SAmir Goldstein return err; 65859be0971SAmir Goldstein } else { 65959be0971SAmir Goldstein /* 66059be0971SAmir Goldstein * Mark parent "impure" because it may now contain non-pure 66159be0971SAmir Goldstein * upper 66259be0971SAmir Goldstein */ 66359be0971SAmir Goldstein err = ovl_set_impure(c->parent, c->destdir); 66459be0971SAmir Goldstein if (err) 66559be0971SAmir Goldstein return err; 66659be0971SAmir Goldstein } 667f3a15685SAmir Goldstein 66801ad3eb8SAmir Goldstein /* Should we copyup with O_TMPFILE or with workdir? */ 66923f0ab13SMiklos Szeredi if (S_ISREG(c->stat.mode) && ofs->tmpfile) { 67023f0ab13SMiklos Szeredi c->tmpfile = true; 67159be0971SAmir Goldstein err = ovl_copy_up_locked(c); 67259be0971SAmir Goldstein } else { 6735820dc08SAmir Goldstein err = ovl_lock_rename_workdir(c->workdir, c->destdir); 6745820dc08SAmir Goldstein if (!err) { 67523f0ab13SMiklos Szeredi err = ovl_copy_up_locked(c); 67659be0971SAmir Goldstein unlock_rename(c->workdir, c->destdir); 67759be0971SAmir Goldstein } 67859be0971SAmir Goldstein } 67959be0971SAmir Goldstein 680016b720fSAmir Goldstein if (!err && c->indexed) 68159be0971SAmir Goldstein ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); 682016b720fSAmir Goldstein 683016b720fSAmir Goldstein if (to_index) { 68459be0971SAmir Goldstein kfree(c->destname.name); 68559be0971SAmir Goldstein } else if (!err) { 68659be0971SAmir Goldstein struct inode *udir = d_inode(c->destdir); 68759be0971SAmir Goldstein 68859be0971SAmir Goldstein /* Restore timestamps on parent (best effort) */ 68959be0971SAmir Goldstein inode_lock(udir); 69059be0971SAmir Goldstein ovl_set_timestamps(c->destdir, &c->pstat); 69159be0971SAmir Goldstein inode_unlock(udir); 69259be0971SAmir Goldstein 69359be0971SAmir Goldstein ovl_dentry_set_upper_alias(c->dentry); 694fd210b7dSMiklos Szeredi } 695a6fb235aSMiklos Szeredi 696a6fb235aSMiklos Szeredi return err; 697a6fb235aSMiklos Szeredi } 698a6fb235aSMiklos Szeredi 699a6fb235aSMiklos Szeredi static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, 700a6fb235aSMiklos Szeredi int flags) 701a6fb235aSMiklos Szeredi { 702a6fb235aSMiklos Szeredi int err; 703a6fb235aSMiklos Szeredi DEFINE_DELAYED_CALL(done); 704a6fb235aSMiklos Szeredi struct path parentpath; 705a6fb235aSMiklos Szeredi struct ovl_copy_up_ctx ctx = { 706a6fb235aSMiklos Szeredi .parent = parent, 707a6fb235aSMiklos Szeredi .dentry = dentry, 708a6fb235aSMiklos Szeredi .workdir = ovl_workdir(dentry), 709a6fb235aSMiklos Szeredi }; 710a6fb235aSMiklos Szeredi 711a6fb235aSMiklos Szeredi if (WARN_ON(!ctx.workdir)) 712a6fb235aSMiklos Szeredi return -EROFS; 713a6fb235aSMiklos Szeredi 714a6fb235aSMiklos Szeredi ovl_path_lower(dentry, &ctx.lowerpath); 715a6fb235aSMiklos Szeredi err = vfs_getattr(&ctx.lowerpath, &ctx.stat, 716a6fb235aSMiklos Szeredi STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); 717a6fb235aSMiklos Szeredi if (err) 718a6fb235aSMiklos Szeredi return err; 719a6fb235aSMiklos Szeredi 720a6fb235aSMiklos Szeredi ovl_path_upper(parent, &parentpath); 72159be0971SAmir Goldstein ctx.destdir = parentpath.dentry; 72259be0971SAmir Goldstein ctx.destname = dentry->d_name; 723a6fb235aSMiklos Szeredi 724a6fb235aSMiklos Szeredi err = vfs_getattr(&parentpath, &ctx.pstat, 725a6fb235aSMiklos Szeredi STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); 726a6fb235aSMiklos Szeredi if (err) 727a6fb235aSMiklos Szeredi return err; 728a6fb235aSMiklos Szeredi 729a6fb235aSMiklos Szeredi /* maybe truncate regular file. this has no effect on dirs */ 730a6fb235aSMiklos Szeredi if (flags & O_TRUNC) 731a6fb235aSMiklos Szeredi ctx.stat.size = 0; 732a6fb235aSMiklos Szeredi 733a6fb235aSMiklos Szeredi if (S_ISLNK(ctx.stat.mode)) { 734a6fb235aSMiklos Szeredi ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done); 735a6fb235aSMiklos Szeredi if (IS_ERR(ctx.link)) 736a6fb235aSMiklos Szeredi return PTR_ERR(ctx.link); 737a6fb235aSMiklos Szeredi } 738a6fb235aSMiklos Szeredi ovl_do_check_copy_up(ctx.lowerpath.dentry); 739a6fb235aSMiklos Szeredi 740fd210b7dSMiklos Szeredi err = ovl_copy_up_start(dentry); 741fd210b7dSMiklos Szeredi /* err < 0: interrupted, err > 0: raced with another copy-up */ 742fd210b7dSMiklos Szeredi if (unlikely(err)) { 743fd210b7dSMiklos Szeredi if (err > 0) 744fd210b7dSMiklos Szeredi err = 0; 745fd210b7dSMiklos Szeredi } else { 74659be0971SAmir Goldstein if (!ovl_dentry_upper(dentry)) 747a6fb235aSMiklos Szeredi err = ovl_do_copy_up(&ctx); 74859be0971SAmir Goldstein if (!err && !ovl_dentry_has_upper_alias(dentry)) 749f4439de1SAmir Goldstein err = ovl_link_up(&ctx); 750fd210b7dSMiklos Szeredi ovl_copy_up_end(dentry); 751fd210b7dSMiklos Szeredi } 7527764235bSMiklos Szeredi do_delayed_call(&done); 753e9be9d5eSMiklos Szeredi 754e9be9d5eSMiklos Szeredi return err; 755e9be9d5eSMiklos Szeredi } 756e9be9d5eSMiklos Szeredi 7579aba6521SAmir Goldstein int ovl_copy_up_flags(struct dentry *dentry, int flags) 758e9be9d5eSMiklos Szeredi { 7598eac98b8SVivek Goyal int err = 0; 7608eac98b8SVivek Goyal const struct cred *old_cred = ovl_override_creds(dentry->d_sb); 761e9be9d5eSMiklos Szeredi 762e9be9d5eSMiklos Szeredi while (!err) { 763e9be9d5eSMiklos Szeredi struct dentry *next; 764e9be9d5eSMiklos Szeredi struct dentry *parent; 765e9be9d5eSMiklos Szeredi 76659be0971SAmir Goldstein /* 76759be0971SAmir Goldstein * Check if copy-up has happened as well as for upper alias (in 76859be0971SAmir Goldstein * case of hard links) is there. 76959be0971SAmir Goldstein * 77059be0971SAmir Goldstein * Both checks are lockless: 77159be0971SAmir Goldstein * - false negatives: will recheck under oi->lock 77259be0971SAmir Goldstein * - false positives: 77359be0971SAmir Goldstein * + ovl_dentry_upper() uses memory barriers to ensure the 77459be0971SAmir Goldstein * upper dentry is up-to-date 77559be0971SAmir Goldstein * + ovl_dentry_has_upper_alias() relies on locking of 77659be0971SAmir Goldstein * upper parent i_rwsem to prevent reordering copy-up 77759be0971SAmir Goldstein * with rename. 77859be0971SAmir Goldstein */ 77959be0971SAmir Goldstein if (ovl_dentry_upper(dentry) && 78059be0971SAmir Goldstein ovl_dentry_has_upper_alias(dentry)) 781e9be9d5eSMiklos Szeredi break; 782e9be9d5eSMiklos Szeredi 783e9be9d5eSMiklos Szeredi next = dget(dentry); 784e9be9d5eSMiklos Szeredi /* find the topmost dentry not yet copied up */ 785e9be9d5eSMiklos Szeredi for (;;) { 786e9be9d5eSMiklos Szeredi parent = dget_parent(next); 787e9be9d5eSMiklos Szeredi 78859be0971SAmir Goldstein if (ovl_dentry_upper(parent)) 789e9be9d5eSMiklos Szeredi break; 790e9be9d5eSMiklos Szeredi 791e9be9d5eSMiklos Szeredi dput(next); 792e9be9d5eSMiklos Szeredi next = parent; 793e9be9d5eSMiklos Szeredi } 794e9be9d5eSMiklos Szeredi 795a6fb235aSMiklos Szeredi err = ovl_copy_up_one(parent, next, flags); 796e9be9d5eSMiklos Szeredi 797e9be9d5eSMiklos Szeredi dput(parent); 798e9be9d5eSMiklos Szeredi dput(next); 799e9be9d5eSMiklos Szeredi } 8008eac98b8SVivek Goyal revert_creds(old_cred); 801e9be9d5eSMiklos Szeredi 802e9be9d5eSMiklos Szeredi return err; 803e9be9d5eSMiklos Szeredi } 8049aba6521SAmir Goldstein 8059aba6521SAmir Goldstein int ovl_copy_up(struct dentry *dentry) 8069aba6521SAmir Goldstein { 8079aba6521SAmir Goldstein return ovl_copy_up_flags(dentry, 0); 8089aba6521SAmir Goldstein } 809