1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (C) 2011 Novell Inc.
7 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/file.h>
11 #include <linux/fileattr.h>
12 #include <linux/splice.h>
13 #include <linux/xattr.h>
14 #include <linux/security.h>
15 #include <linux/uaccess.h>
16 #include <linux/sched/signal.h>
17 #include <linux/cred.h>
18 #include <linux/namei.h>
19 #include <linux/fdtable.h>
20 #include <linux/ratelimit.h>
21 #include <linux/exportfs.h>
22 #include "overlayfs.h"
24 #define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
26 static int ovl_ccup_set(const char *buf, const struct kernel_param *param)
28 pr_warn("\"check_copy_up\" module option is obsolete\n");
32 static int ovl_ccup_get(char *buf, const struct kernel_param *param)
34 return sprintf(buf, "N\n");
37 module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644);
38 MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing");
40 static bool ovl_must_copy_xattr(const char *name)
42 return !strcmp(name, XATTR_POSIX_ACL_ACCESS) ||
43 !strcmp(name, XATTR_POSIX_ACL_DEFAULT) ||
44 !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
47 static int ovl_copy_acl(struct ovl_fs *ofs, const struct path *path,
48 struct dentry *dentry, const char *acl_name)
51 struct posix_acl *clone, *real_acl = NULL;
53 real_acl = ovl_get_acl_path(path, acl_name, false);
57 if (IS_ERR(real_acl)) {
58 err = PTR_ERR(real_acl);
59 if (err == -ENODATA || err == -EOPNOTSUPP)
64 clone = posix_acl_clone(real_acl, GFP_KERNEL);
65 posix_acl_release(real_acl); /* release original acl */
69 err = ovl_do_set_acl(ofs, dentry, acl_name, clone);
71 /* release cloned acl */
72 posix_acl_release(clone);
76 int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new)
78 struct dentry *old = oldpath->dentry;
79 ssize_t list_size, size, value_size = 0;
80 char *buf, *name, *value = NULL;
84 if (!old->d_inode->i_op->listxattr || !new->d_inode->i_op->listxattr)
87 list_size = vfs_listxattr(old, NULL, 0);
89 if (list_size == -EOPNOTSUPP)
94 buf = kvzalloc(list_size, GFP_KERNEL);
98 list_size = vfs_listxattr(old, buf, list_size);
104 for (name = buf; list_size; name += slen) {
105 slen = strnlen(name, list_size) + 1;
107 /* underlying fs providing us with an broken xattr list? */
108 if (WARN_ON(slen > list_size)) {
114 if (ovl_is_private_xattr(sb, name))
117 error = security_inode_copy_up_xattr(name);
118 if (error < 0 && error != -EOPNOTSUPP)
122 continue; /* Discard */
125 if (is_posix_acl_xattr(name)) {
126 error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name);
129 /* POSIX ACLs must be copied. */
134 size = ovl_do_getxattr(oldpath, name, value, value_size);
136 size = ovl_do_getxattr(oldpath, name, NULL, 0);
143 if (size > value_size) {
146 new = kvmalloc(size, GFP_KERNEL);
157 error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0);
159 if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
162 /* Ignore failure to copy unknown xattrs */
172 static int ovl_copy_fileattr(struct inode *inode, const struct path *old,
173 const struct path *new)
175 struct fileattr oldfa = { .flags_valid = true };
176 struct fileattr newfa = { .flags_valid = true };
179 err = ovl_real_fileattr_get(old, &oldfa);
181 /* Ntfs-3g returns -EINVAL for "no fileattr support" */
182 if (err == -ENOTTY || err == -EINVAL)
184 pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
190 * We cannot set immutable and append-only flags on upper inode,
191 * because we would not be able to link upper inode to upper dir
192 * not set overlay private xattr on upper inode.
193 * Store these flags in overlay.protattr xattr instead.
195 if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
196 err = ovl_set_protattr(inode, new->dentry, &oldfa);
198 pr_warn_once("copying fileattr: no xattr on upper\n");
203 /* Don't bother copying flags if none are set */
204 if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK))
207 err = ovl_real_fileattr_get(new, &newfa);
210 * Returning an error if upper doesn't support fileattr will
211 * result in a regression, so revert to the old behavior.
213 if (err == -ENOTTY || err == -EINVAL) {
214 pr_warn_once("copying fileattr: no support on upper\n");
217 pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
222 BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL);
223 newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK;
224 newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK);
226 BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON);
227 newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK;
228 newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK);
230 return ovl_real_fileattr_set(new, &newfa);
233 static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry,
234 struct file *new_file, loff_t len)
236 struct path datapath;
237 struct file *old_file;
241 loff_t data_pos = -1;
243 bool skip_hole = false;
246 ovl_path_lowerdata(dentry, &datapath);
247 if (WARN_ON(datapath.dentry == NULL))
250 old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY);
251 if (IS_ERR(old_file))
252 return PTR_ERR(old_file);
254 /* Try to use clone_file_range to clone up within the same fs */
255 cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
258 /* Couldn't clone, so now we try to copy the data */
260 /* Check if lower fs supports seek operation */
261 if (old_file->f_mode & FMODE_LSEEK)
265 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
271 if (signal_pending_state(TASK_KILLABLE, current)) {
277 * Fill zero for hole will cost unnecessary disk space
278 * and meanwhile slow down the copy-up speed, so we do
279 * an optimization for hole during copy-up, it relies
280 * on SEEK_DATA implementation in lower fs so if lower
281 * fs does not support it, copy-up will behave as before.
283 * Detail logic of hole detection as below:
284 * When we detect next data position is larger than current
285 * position we will skip that hole, otherwise we copy
286 * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
287 * it may not recognize all kind of holes and sometimes
288 * only skips partial of hole area. However, it will be
289 * enough for most of the use cases.
292 if (skip_hole && data_pos < old_pos) {
293 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
294 if (data_pos > old_pos) {
295 hole_len = data_pos - old_pos;
297 old_pos = new_pos = data_pos;
299 } else if (data_pos == -ENXIO) {
301 } else if (data_pos < 0) {
306 bytes = do_splice_direct(old_file, &old_pos,
308 this_len, SPLICE_F_MOVE);
313 WARN_ON(old_pos != new_pos);
317 if (!error && ovl_should_sync(ofs))
318 error = vfs_fsync(new_file, 0);
324 static int ovl_set_size(struct ovl_fs *ofs,
325 struct dentry *upperdentry, struct kstat *stat)
327 struct iattr attr = {
328 .ia_valid = ATTR_SIZE,
329 .ia_size = stat->size,
332 return ovl_do_notify_change(ofs, upperdentry, &attr);
335 static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry,
338 struct iattr attr = {
340 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
341 .ia_atime = stat->atime,
342 .ia_mtime = stat->mtime,
345 return ovl_do_notify_change(ofs, upperdentry, &attr);
348 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry,
353 if (!S_ISLNK(stat->mode)) {
354 struct iattr attr = {
355 .ia_valid = ATTR_MODE,
356 .ia_mode = stat->mode,
358 err = ovl_do_notify_change(ofs, upperdentry, &attr);
361 struct iattr attr = {
362 .ia_valid = ATTR_UID | ATTR_GID,
363 .ia_vfsuid = VFSUIDT_INIT(stat->uid),
364 .ia_vfsgid = VFSGIDT_INIT(stat->gid),
366 err = ovl_do_notify_change(ofs, upperdentry, &attr);
369 ovl_set_timestamps(ofs, upperdentry, stat);
374 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
379 int buflen = MAX_HANDLE_SZ;
380 uuid_t *uuid = &real->d_sb->s_uuid;
383 /* Make sure the real fid stays 32bit aligned */
384 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
385 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
387 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
389 return ERR_PTR(-ENOMEM);
392 * We encode a non-connectable file handle for non-dir, because we
393 * only need to find the lower inode number and we don't want to pay
394 * the price or reconnecting the dentry.
396 dwords = buflen >> 2;
397 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
398 buflen = (dwords << 2);
401 if (WARN_ON(fh_type < 0) ||
402 WARN_ON(buflen > MAX_HANDLE_SZ) ||
403 WARN_ON(fh_type == FILEID_INVALID))
406 fh->fb.version = OVL_FH_VERSION;
407 fh->fb.magic = OVL_FH_MAGIC;
408 fh->fb.type = fh_type;
409 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
411 * When we will want to decode an overlay dentry from this handle
412 * and all layers are on the same fs, if we get a disconncted real
413 * dentry when we decode fid, the only way to tell if we should assign
414 * it to upperdentry or to lowerstack is by checking this flag.
417 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
418 fh->fb.len = sizeof(fh->fb) + buflen;
419 if (ovl_origin_uuid(ofs))
429 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
430 struct dentry *upper)
432 const struct ovl_fh *fh = NULL;
436 * When lower layer doesn't support export operations store a 'null' fh,
437 * so we can use the overlay.origin xattr to distignuish between a copy
438 * up and a pure upper inode.
440 if (ovl_can_decode_fh(lower->d_sb)) {
441 fh = ovl_encode_real_fh(ofs, lower, false);
447 * Do not fail when upper doesn't support xattrs.
449 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
450 fh ? fh->fb.len : 0, 0);
453 /* Ignore -EPERM from setting "user.*" on symlink/special */
454 return err == -EPERM ? 0 : err;
457 /* Store file handle of @upper dir in @index dir entry */
458 static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
459 struct dentry *index)
461 const struct ovl_fh *fh;
464 fh = ovl_encode_real_fh(ofs, upper, true);
468 err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
475 * Create and install index entry.
477 * Caller must hold i_mutex on indexdir.
479 static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
480 struct dentry *upper)
482 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
483 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
484 struct inode *dir = d_inode(indexdir);
485 struct dentry *index = NULL;
486 struct dentry *temp = NULL;
487 struct qstr name = { };
491 * For now this is only used for creating index entry for directories,
492 * because non-dir are copied up directly to index and then hardlinked
495 * TODO: implement create index for non-dir, so we can call it when
496 * encoding file handle for non-dir in case index does not exist.
498 if (WARN_ON(!d_is_dir(dentry)))
501 /* Directory not expected to be indexed before copy up */
502 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
505 err = ovl_get_index_name(ofs, origin, &name);
509 temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0));
514 err = ovl_set_upper_fh(ofs, upper, temp);
518 index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
520 err = PTR_ERR(index);
522 err = ovl_do_rename(ofs, dir, temp, dir, index, 0);
527 ovl_cleanup(ofs, dir, temp);
534 struct ovl_copy_up_ctx {
535 struct dentry *parent;
536 struct dentry *dentry;
537 struct path lowerpath;
541 struct dentry *destdir;
542 struct qstr destname;
543 struct dentry *workdir;
547 bool metacopy_digest;
550 static int ovl_link_up(struct ovl_copy_up_ctx *c)
553 struct dentry *upper;
554 struct dentry *upperdir = ovl_dentry_upper(c->parent);
555 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
556 struct inode *udir = d_inode(upperdir);
558 /* Mark parent "impure" because it may now contain non-pure upper */
559 err = ovl_set_impure(c->parent, upperdir);
563 err = ovl_set_nlink_lower(c->dentry);
567 inode_lock_nested(udir, I_MUTEX_PARENT);
568 upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir,
569 c->dentry->d_name.len);
570 err = PTR_ERR(upper);
571 if (!IS_ERR(upper)) {
572 err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper);
576 /* Restore timestamps on parent (best effort) */
577 ovl_set_timestamps(ofs, upperdir, &c->pstat);
578 ovl_dentry_set_upper_alias(c->dentry);
579 ovl_dentry_update_reval(c->dentry, upper);
586 err = ovl_set_nlink_upper(c->dentry);
591 static int ovl_copy_up_data(struct ovl_copy_up_ctx *c, const struct path *temp)
593 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
594 struct file *new_file;
597 if (!S_ISREG(c->stat.mode) || c->metacopy || !c->stat.size)
600 new_file = ovl_path_open(temp, O_LARGEFILE | O_WRONLY);
601 if (IS_ERR(new_file))
602 return PTR_ERR(new_file);
604 err = ovl_copy_up_file(ofs, c->dentry, new_file, c->stat.size);
610 static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp)
612 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
613 struct inode *inode = d_inode(c->dentry);
614 struct path upperpath = { .mnt = ovl_upper_mnt(ofs), .dentry = temp };
617 err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp);
621 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK &&
622 (S_ISREG(c->stat.mode) || S_ISDIR(c->stat.mode))) {
624 * Copy the fileattr inode flags that are the source of already
627 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath);
633 * Store identifier of lower inode in upper inode xattr to
634 * allow lookup of the copy up origin inode.
636 * Don't set origin when we are breaking the association with a lower
640 err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
646 struct path lowerdatapath;
647 struct ovl_metacopy metacopy_data = OVL_METACOPY_INIT;
649 ovl_path_lowerdata(c->dentry, &lowerdatapath);
650 if (WARN_ON_ONCE(lowerdatapath.dentry == NULL))
652 err = ovl_get_verity_digest(ofs, &lowerdatapath, &metacopy_data);
656 if (metacopy_data.digest_algo)
657 c->metacopy_digest = true;
659 err = ovl_set_metacopy_xattr(ofs, temp, &metacopy_data);
664 inode_lock(temp->d_inode);
665 if (S_ISREG(c->stat.mode))
666 err = ovl_set_size(ofs, temp, &c->stat);
668 err = ovl_set_attr(ofs, temp, &c->stat);
669 inode_unlock(temp->d_inode);
674 struct ovl_cu_creds {
675 const struct cred *old;
679 static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
683 cc->old = cc->new = NULL;
684 err = security_inode_copy_up(dentry, &cc->new);
689 cc->old = override_creds(cc->new);
694 static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
697 revert_creds(cc->old);
703 * Copyup using workdir to prepare temp file. Used when copying up directories,
704 * special files or when upper fs doesn't support O_TMPFILE.
706 static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
708 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
710 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
711 struct path path = { .mnt = ovl_upper_mnt(ofs) };
712 struct dentry *temp, *upper;
713 struct ovl_cu_creds cc;
715 struct ovl_cattr cattr = {
716 /* Can't properly set mode on creation because of the umask */
717 .mode = c->stat.mode & S_IFMT,
718 .rdev = c->stat.rdev,
722 /* workdir and destdir could be the same when copying up to indexdir */
724 if (lock_rename(c->workdir, c->destdir) != NULL)
727 err = ovl_prep_cu_creds(c->dentry, &cc);
731 temp = ovl_create_temp(ofs, c->workdir, &cattr);
732 ovl_revert_cu_creds(&cc);
739 * Copy up data first and then xattrs. Writing data after
740 * xattrs will remove security.capability xattr automatically.
743 err = ovl_copy_up_data(c, &path);
747 err = ovl_copy_up_metadata(c, temp);
751 if (S_ISDIR(c->stat.mode) && c->indexed) {
752 err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
757 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
759 err = PTR_ERR(upper);
763 err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0);
768 inode = d_inode(c->dentry);
769 if (c->metacopy_digest)
770 ovl_set_flag(OVL_HAS_DIGEST, inode);
772 ovl_clear_flag(OVL_HAS_DIGEST, inode);
773 ovl_clear_flag(OVL_VERIFIED_DIGEST, inode);
776 ovl_set_upperdata(inode);
777 ovl_inode_update(inode, temp);
778 if (S_ISDIR(inode->i_mode))
779 ovl_set_flag(OVL_WHITEOUTS, inode);
781 unlock_rename(c->workdir, c->destdir);
786 ovl_cleanup(ofs, wdir, temp);
791 /* Copyup using O_TMPFILE which does not require cross dir locking */
792 static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
794 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
795 struct inode *udir = d_inode(c->destdir);
796 struct dentry *temp, *upper;
797 struct file *tmpfile;
798 struct ovl_cu_creds cc;
801 err = ovl_prep_cu_creds(c->dentry, &cc);
805 tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode);
806 ovl_revert_cu_creds(&cc);
809 return PTR_ERR(tmpfile);
811 temp = tmpfile->f_path.dentry;
812 if (!c->metacopy && c->stat.size) {
813 err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size);
818 err = ovl_copy_up_metadata(c, temp);
822 inode_lock_nested(udir, I_MUTEX_PARENT);
824 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
826 err = PTR_ERR(upper);
827 if (!IS_ERR(upper)) {
828 err = ovl_do_link(ofs, temp, udir, upper);
836 if (c->metacopy_digest)
837 ovl_set_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
839 ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
840 ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry));
843 ovl_set_upperdata(d_inode(c->dentry));
844 ovl_inode_update(d_inode(c->dentry), dget(temp));
852 * Copy up a single dentry
854 * All renames start with copy up of source if necessary. The actual
855 * rename will only proceed once the copy up was successful. Copy up uses
856 * upper parent i_mutex for exclusion. Since rename can change d_parent it
857 * is possible that the copy up will lock the old parent. At that point
858 * the file will have already been copied up anyway.
860 static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
863 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
864 bool to_index = false;
867 * Indexed non-dir is copied up directly to the index entry and then
868 * hardlinked to upper dir. Indexed dir is copied up to indexdir,
869 * then index entry is created and then copied up dir installed.
870 * Copying dir up to indexdir instead of workdir simplifies locking.
872 if (ovl_need_index(c->dentry)) {
874 if (S_ISDIR(c->stat.mode))
875 c->workdir = ovl_indexdir(c->dentry->d_sb);
880 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
884 c->destdir = ovl_indexdir(c->dentry->d_sb);
885 err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
888 } else if (WARN_ON(!c->parent)) {
889 /* Disconnected dentry must be copied up to index dir */
893 * Mark parent "impure" because it may now contain non-pure
896 err = ovl_set_impure(c->parent, c->destdir);
901 /* Should we copyup with O_TMPFILE or with workdir? */
902 if (S_ISREG(c->stat.mode) && ofs->tmpfile)
903 err = ovl_copy_up_tmpfile(c);
905 err = ovl_copy_up_workdir(c);
910 ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
913 /* Initialize nlink for copy up of disconnected dentry */
914 err = ovl_set_nlink_upper(c->dentry);
916 struct inode *udir = d_inode(c->destdir);
918 /* Restore timestamps on parent (best effort) */
920 ovl_set_timestamps(ofs, c->destdir, &c->pstat);
923 ovl_dentry_set_upper_alias(c->dentry);
924 ovl_dentry_update_reval(c->dentry, ovl_dentry_upper(c->dentry));
929 kfree(c->destname.name);
933 static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
936 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
938 if (!ofs->config.metacopy)
944 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
947 /* Fall back to full copy if no fsverity on source data and we require verity */
948 if (ofs->config.verity_mode == OVL_VERITY_REQUIRE) {
949 struct path lowerdata;
951 ovl_path_lowerdata(dentry, &lowerdata);
953 if (WARN_ON_ONCE(lowerdata.dentry == NULL) ||
954 ovl_ensure_verity_loaded(&lowerdata) ||
955 !fsverity_active(d_inode(lowerdata.dentry))) {
963 static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value)
968 res = ovl_do_getxattr(path, name, NULL, 0);
969 if (res == -ENODATA || res == -EOPNOTSUPP)
973 buf = kzalloc(res, GFP_KERNEL);
977 res = ovl_do_getxattr(path, name, buf, res);
986 /* Copy up data of an inode which was copied up metadata only in the past. */
987 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
989 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
990 struct path upperpath;
992 char *capability = NULL;
995 ovl_path_upper(c->dentry, &upperpath);
996 if (WARN_ON(upperpath.dentry == NULL))
1000 err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS,
1006 err = ovl_copy_up_data(c, &upperpath);
1011 * Writing to upper file will clear security.capability xattr. We
1012 * don't want that to happen for normal copy-up operation.
1015 err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
1016 capability, cap_size, 0);
1022 err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
1026 ovl_clear_flag(OVL_HAS_DIGEST, d_inode(c->dentry));
1027 ovl_clear_flag(OVL_VERIFIED_DIGEST, d_inode(c->dentry));
1028 ovl_set_upperdata(d_inode(c->dentry));
1035 static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
1039 DEFINE_DELAYED_CALL(done);
1040 struct path parentpath;
1041 struct ovl_copy_up_ctx ctx = {
1044 .workdir = ovl_workdir(dentry),
1047 if (WARN_ON(!ctx.workdir))
1050 ovl_path_lower(dentry, &ctx.lowerpath);
1051 err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
1052 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
1056 if (!kuid_has_mapping(current_user_ns(), ctx.stat.uid) ||
1057 !kgid_has_mapping(current_user_ns(), ctx.stat.gid))
1060 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
1063 ovl_path_upper(parent, &parentpath);
1064 ctx.destdir = parentpath.dentry;
1065 ctx.destname = dentry->d_name;
1067 err = vfs_getattr(&parentpath, &ctx.pstat,
1068 STATX_ATIME | STATX_MTIME,
1069 AT_STATX_SYNC_AS_STAT);
1074 /* maybe truncate regular file. this has no effect on dirs */
1075 if (flags & O_TRUNC)
1078 if (S_ISLNK(ctx.stat.mode)) {
1079 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
1080 if (IS_ERR(ctx.link))
1081 return PTR_ERR(ctx.link);
1084 err = ovl_copy_up_start(dentry, flags);
1085 /* err < 0: interrupted, err > 0: raced with another copy-up */
1086 if (unlikely(err)) {
1090 if (!ovl_dentry_upper(dentry))
1091 err = ovl_do_copy_up(&ctx);
1092 if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
1093 err = ovl_link_up(&ctx);
1094 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
1095 err = ovl_copy_up_meta_inode_data(&ctx);
1096 ovl_copy_up_end(dentry);
1098 do_delayed_call(&done);
1103 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
1106 const struct cred *old_cred;
1107 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
1110 * With NFS export, copy up can get called for a disconnected non-dir.
1111 * In this case, we will copy up lower inode to index dir without
1112 * linking it to upper dir.
1114 if (WARN_ON(disconnected && d_is_dir(dentry)))
1118 * We may not need lowerdata if we are only doing metacopy up, but it is
1119 * not very important to optimize this case, so do lazy lowerdata lookup
1120 * before any copy up, so we can do it before taking ovl_inode_lock().
1122 err = ovl_verify_lowerdata(dentry);
1126 old_cred = ovl_override_creds(dentry->d_sb);
1128 struct dentry *next;
1129 struct dentry *parent = NULL;
1131 if (ovl_already_copied_up(dentry, flags))
1134 next = dget(dentry);
1135 /* find the topmost dentry not yet copied up */
1136 for (; !disconnected;) {
1137 parent = dget_parent(next);
1139 if (ovl_dentry_upper(parent))
1146 err = ovl_copy_up_one(parent, next, flags);
1151 revert_creds(old_cred);
1156 static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
1158 /* Copy up of disconnected dentry does not set upper alias */
1159 if (ovl_already_copied_up(dentry, flags))
1162 if (special_file(d_inode(dentry)->i_mode))
1165 if (!ovl_open_flags_need_copy_up(flags))
1171 int ovl_maybe_copy_up(struct dentry *dentry, int flags)
1175 if (ovl_open_need_copy_up(dentry, flags)) {
1176 err = ovl_want_write(dentry);
1178 err = ovl_copy_up_flags(dentry, flags);
1179 ovl_drop_write(dentry);
1186 int ovl_copy_up_with_data(struct dentry *dentry)
1188 return ovl_copy_up_flags(dentry, O_WRONLY);
1191 int ovl_copy_up(struct dentry *dentry)
1193 return ovl_copy_up_flags(dentry, 0);