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28 pr_warn("\"check_copy_up\" module option is obsolete\n");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_opflags & IOP_XATTR) ||
85 !(new->d_inode->i_opflags & IOP_XATTR))
88 list_size = vfs_listxattr(old, NULL, 0);
90 if (list_size == -EOPNOTSUPP)
95 buf = kvzalloc(list_size, GFP_KERNEL);
99 list_size = vfs_listxattr(old, buf, list_size);
100 if (list_size <= 0) {
105 for (name = buf; list_size; name += slen) {
106 slen = strnlen(name, list_size) + 1;
108 /* underlying fs providing us with an broken xattr list? */
109 if (WARN_ON(slen > list_size)) {
115 if (ovl_is_private_xattr(sb, name))
118 error = security_inode_copy_up_xattr(name);
119 if (error < 0 && error != -EOPNOTSUPP)
123 continue; /* Discard */
126 if (is_posix_acl_xattr(name)) {
127 error = ovl_copy_acl(OVL_FS(sb), oldpath, new, name);
130 /* POSIX ACLs must be copied. */
135 size = ovl_do_getxattr(oldpath, name, value, value_size);
137 size = ovl_do_getxattr(oldpath, name, NULL, 0);
144 if (size > value_size) {
147 new = kvmalloc(size, GFP_KERNEL);
158 error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0);
160 if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
163 /* Ignore failure to copy unknown xattrs */
173 static int ovl_copy_fileattr(struct inode *inode, const struct path *old,
174 const struct path *new)
176 struct fileattr oldfa = { .flags_valid = true };
177 struct fileattr newfa = { .flags_valid = true };
180 err = ovl_real_fileattr_get(old, &oldfa);
182 /* Ntfs-3g returns -EINVAL for "no fileattr support" */
183 if (err == -ENOTTY || err == -EINVAL)
185 pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
191 * We cannot set immutable and append-only flags on upper inode,
192 * because we would not be able to link upper inode to upper dir
193 * not set overlay private xattr on upper inode.
194 * Store these flags in overlay.protattr xattr instead.
196 if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
197 err = ovl_set_protattr(inode, new->dentry, &oldfa);
199 pr_warn_once("copying fileattr: no xattr on upper\n");
204 /* Don't bother copying flags if none are set */
205 if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK))
208 err = ovl_real_fileattr_get(new, &newfa);
211 * Returning an error if upper doesn't support fileattr will
212 * result in a regression, so revert to the old behavior.
214 if (err == -ENOTTY || err == -EINVAL) {
215 pr_warn_once("copying fileattr: no support on upper\n");
218 pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
223 BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL);
224 newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK;
225 newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK);
227 BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON);
228 newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK;
229 newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK);
231 return ovl_real_fileattr_set(new, &newfa);
234 static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry,
235 struct file *new_file, loff_t len)
237 struct path datapath;
238 struct file *old_file;
242 loff_t data_pos = -1;
244 bool skip_hole = false;
247 ovl_path_lowerdata(dentry, &datapath);
248 if (WARN_ON(datapath.dentry == NULL))
251 old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY);
252 if (IS_ERR(old_file))
253 return PTR_ERR(old_file);
255 /* Try to use clone_file_range to clone up within the same fs */
256 cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
259 /* Couldn't clone, so now we try to copy the data */
261 /* Check if lower fs supports seek operation */
262 if (old_file->f_mode & FMODE_LSEEK)
266 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
272 if (signal_pending_state(TASK_KILLABLE, current)) {
278 * Fill zero for hole will cost unnecessary disk space
279 * and meanwhile slow down the copy-up speed, so we do
280 * an optimization for hole during copy-up, it relies
281 * on SEEK_DATA implementation in lower fs so if lower
282 * fs does not support it, copy-up will behave as before.
284 * Detail logic of hole detection as below:
285 * When we detect next data position is larger than current
286 * position we will skip that hole, otherwise we copy
287 * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
288 * it may not recognize all kind of holes and sometimes
289 * only skips partial of hole area. However, it will be
290 * enough for most of the use cases.
293 if (skip_hole && data_pos < old_pos) {
294 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
295 if (data_pos > old_pos) {
296 hole_len = data_pos - old_pos;
298 old_pos = new_pos = data_pos;
300 } else if (data_pos == -ENXIO) {
302 } else if (data_pos < 0) {
307 bytes = do_splice_direct(old_file, &old_pos,
309 this_len, SPLICE_F_MOVE);
314 WARN_ON(old_pos != new_pos);
318 if (!error && ovl_should_sync(ofs))
319 error = vfs_fsync(new_file, 0);
325 static int ovl_set_size(struct ovl_fs *ofs,
326 struct dentry *upperdentry, struct kstat *stat)
328 struct iattr attr = {
329 .ia_valid = ATTR_SIZE,
330 .ia_size = stat->size,
333 return ovl_do_notify_change(ofs, upperdentry, &attr);
336 static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry,
339 struct iattr attr = {
341 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
342 .ia_atime = stat->atime,
343 .ia_mtime = stat->mtime,
346 return ovl_do_notify_change(ofs, upperdentry, &attr);
349 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry,
354 if (!S_ISLNK(stat->mode)) {
355 struct iattr attr = {
356 .ia_valid = ATTR_MODE,
357 .ia_mode = stat->mode,
359 err = ovl_do_notify_change(ofs, upperdentry, &attr);
362 struct iattr attr = {
363 .ia_valid = ATTR_UID | ATTR_GID,
364 .ia_vfsuid = VFSUIDT_INIT(stat->uid),
365 .ia_vfsgid = VFSGIDT_INIT(stat->gid),
367 err = ovl_do_notify_change(ofs, upperdentry, &attr);
370 ovl_set_timestamps(ofs, upperdentry, stat);
375 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
380 int buflen = MAX_HANDLE_SZ;
381 uuid_t *uuid = &real->d_sb->s_uuid;
384 /* Make sure the real fid stays 32bit aligned */
385 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
386 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
388 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
390 return ERR_PTR(-ENOMEM);
393 * We encode a non-connectable file handle for non-dir, because we
394 * only need to find the lower inode number and we don't want to pay
395 * the price or reconnecting the dentry.
397 dwords = buflen >> 2;
398 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
399 buflen = (dwords << 2);
402 if (WARN_ON(fh_type < 0) ||
403 WARN_ON(buflen > MAX_HANDLE_SZ) ||
404 WARN_ON(fh_type == FILEID_INVALID))
407 fh->fb.version = OVL_FH_VERSION;
408 fh->fb.magic = OVL_FH_MAGIC;
409 fh->fb.type = fh_type;
410 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
412 * When we will want to decode an overlay dentry from this handle
413 * and all layers are on the same fs, if we get a disconncted real
414 * dentry when we decode fid, the only way to tell if we should assign
415 * it to upperdentry or to lowerstack is by checking this flag.
418 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
419 fh->fb.len = sizeof(fh->fb) + buflen;
420 if (ofs->config.uuid)
430 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
431 struct dentry *upper)
433 const struct ovl_fh *fh = NULL;
437 * When lower layer doesn't support export operations store a 'null' fh,
438 * so we can use the overlay.origin xattr to distignuish between a copy
439 * up and a pure upper inode.
441 if (ovl_can_decode_fh(lower->d_sb)) {
442 fh = ovl_encode_real_fh(ofs, lower, false);
448 * Do not fail when upper doesn't support xattrs.
450 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
451 fh ? fh->fb.len : 0, 0);
454 /* Ignore -EPERM from setting "user.*" on symlink/special */
455 return err == -EPERM ? 0 : err;
458 /* Store file handle of @upper dir in @index dir entry */
459 static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
460 struct dentry *index)
462 const struct ovl_fh *fh;
465 fh = ovl_encode_real_fh(ofs, upper, true);
469 err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
476 * Create and install index entry.
478 * Caller must hold i_mutex on indexdir.
480 static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
481 struct dentry *upper)
483 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
484 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
485 struct inode *dir = d_inode(indexdir);
486 struct dentry *index = NULL;
487 struct dentry *temp = NULL;
488 struct qstr name = { };
492 * For now this is only used for creating index entry for directories,
493 * because non-dir are copied up directly to index and then hardlinked
496 * TODO: implement create index for non-dir, so we can call it when
497 * encoding file handle for non-dir in case index does not exist.
499 if (WARN_ON(!d_is_dir(dentry)))
502 /* Directory not expected to be indexed before copy up */
503 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
506 err = ovl_get_index_name(ofs, origin, &name);
510 temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0));
515 err = ovl_set_upper_fh(ofs, upper, temp);
519 index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
521 err = PTR_ERR(index);
523 err = ovl_do_rename(ofs, dir, temp, dir, index, 0);
528 ovl_cleanup(ofs, dir, temp);
535 struct ovl_copy_up_ctx {
536 struct dentry *parent;
537 struct dentry *dentry;
538 struct path lowerpath;
542 struct dentry *destdir;
543 struct qstr destname;
544 struct dentry *workdir;
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);
585 err = ovl_set_nlink_upper(c->dentry);
590 static int ovl_copy_up_data(struct ovl_copy_up_ctx *c, const struct path *temp)
592 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
593 struct file *new_file;
596 if (!S_ISREG(c->stat.mode) || c->metacopy || !c->stat.size)
599 new_file = ovl_path_open(temp, O_LARGEFILE | O_WRONLY);
600 if (IS_ERR(new_file))
601 return PTR_ERR(new_file);
603 err = ovl_copy_up_file(ofs, c->dentry, new_file, c->stat.size);
609 static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp)
611 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
612 struct inode *inode = d_inode(c->dentry);
613 struct path upperpath = { .mnt = ovl_upper_mnt(ofs), .dentry = temp };
616 err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp);
620 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK) {
622 * Copy the fileattr inode flags that are the source of already
625 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath);
631 * Store identifier of lower inode in upper inode xattr to
632 * allow lookup of the copy up origin inode.
634 * Don't set origin when we are breaking the association with a lower
638 err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
644 err = ovl_check_setxattr(ofs, temp, OVL_XATTR_METACOPY,
645 NULL, 0, -EOPNOTSUPP);
650 inode_lock(temp->d_inode);
651 if (S_ISREG(c->stat.mode))
652 err = ovl_set_size(ofs, temp, &c->stat);
654 err = ovl_set_attr(ofs, temp, &c->stat);
655 inode_unlock(temp->d_inode);
660 struct ovl_cu_creds {
661 const struct cred *old;
665 static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
669 cc->old = cc->new = NULL;
670 err = security_inode_copy_up(dentry, &cc->new);
675 cc->old = override_creds(cc->new);
680 static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
683 revert_creds(cc->old);
689 * Copyup using workdir to prepare temp file. Used when copying up directories,
690 * special files or when upper fs doesn't support O_TMPFILE.
692 static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
694 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
696 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
697 struct path path = { .mnt = ovl_upper_mnt(ofs) };
698 struct dentry *temp, *upper;
699 struct ovl_cu_creds cc;
701 struct ovl_cattr cattr = {
702 /* Can't properly set mode on creation because of the umask */
703 .mode = c->stat.mode & S_IFMT,
704 .rdev = c->stat.rdev,
708 /* workdir and destdir could be the same when copying up to indexdir */
710 if (lock_rename(c->workdir, c->destdir) != NULL)
713 err = ovl_prep_cu_creds(c->dentry, &cc);
717 temp = ovl_create_temp(ofs, c->workdir, &cattr);
718 ovl_revert_cu_creds(&cc);
725 * Copy up data first and then xattrs. Writing data after
726 * xattrs will remove security.capability xattr automatically.
729 err = ovl_copy_up_data(c, &path);
733 err = ovl_copy_up_metadata(c, temp);
737 if (S_ISDIR(c->stat.mode) && c->indexed) {
738 err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
743 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
745 err = PTR_ERR(upper);
749 err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0);
755 ovl_set_upperdata(d_inode(c->dentry));
756 inode = d_inode(c->dentry);
757 ovl_inode_update(inode, temp);
758 if (S_ISDIR(inode->i_mode))
759 ovl_set_flag(OVL_WHITEOUTS, inode);
761 unlock_rename(c->workdir, c->destdir);
766 ovl_cleanup(ofs, wdir, temp);
771 /* Copyup using O_TMPFILE which does not require cross dir locking */
772 static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
774 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
775 struct inode *udir = d_inode(c->destdir);
776 struct dentry *temp, *upper;
777 struct file *tmpfile;
778 struct ovl_cu_creds cc;
781 err = ovl_prep_cu_creds(c->dentry, &cc);
785 tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode);
786 ovl_revert_cu_creds(&cc);
789 return PTR_ERR(tmpfile);
791 temp = tmpfile->f_path.dentry;
792 if (!c->metacopy && c->stat.size) {
793 err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size);
798 err = ovl_copy_up_metadata(c, temp);
802 inode_lock_nested(udir, I_MUTEX_PARENT);
804 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
806 err = PTR_ERR(upper);
807 if (!IS_ERR(upper)) {
808 err = ovl_do_link(ofs, temp, udir, upper);
817 ovl_set_upperdata(d_inode(c->dentry));
818 ovl_inode_update(d_inode(c->dentry), dget(temp));
826 * Copy up a single dentry
828 * All renames start with copy up of source if necessary. The actual
829 * rename will only proceed once the copy up was successful. Copy up uses
830 * upper parent i_mutex for exclusion. Since rename can change d_parent it
831 * is possible that the copy up will lock the old parent. At that point
832 * the file will have already been copied up anyway.
834 static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
837 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
838 bool to_index = false;
841 * Indexed non-dir is copied up directly to the index entry and then
842 * hardlinked to upper dir. Indexed dir is copied up to indexdir,
843 * then index entry is created and then copied up dir installed.
844 * Copying dir up to indexdir instead of workdir simplifies locking.
846 if (ovl_need_index(c->dentry)) {
848 if (S_ISDIR(c->stat.mode))
849 c->workdir = ovl_indexdir(c->dentry->d_sb);
854 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
858 c->destdir = ovl_indexdir(c->dentry->d_sb);
859 err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
862 } else if (WARN_ON(!c->parent)) {
863 /* Disconnected dentry must be copied up to index dir */
867 * Mark parent "impure" because it may now contain non-pure
870 err = ovl_set_impure(c->parent, c->destdir);
875 /* Should we copyup with O_TMPFILE or with workdir? */
876 if (S_ISREG(c->stat.mode) && ofs->tmpfile)
877 err = ovl_copy_up_tmpfile(c);
879 err = ovl_copy_up_workdir(c);
884 ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
887 /* Initialize nlink for copy up of disconnected dentry */
888 err = ovl_set_nlink_upper(c->dentry);
890 struct inode *udir = d_inode(c->destdir);
892 /* Restore timestamps on parent (best effort) */
894 ovl_set_timestamps(ofs, c->destdir, &c->pstat);
897 ovl_dentry_set_upper_alias(c->dentry);
902 kfree(c->destname.name);
906 static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
909 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
911 if (!ofs->config.metacopy)
917 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
923 static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value)
928 res = ovl_do_getxattr(path, name, NULL, 0);
929 if (res == -ENODATA || res == -EOPNOTSUPP)
933 buf = kzalloc(res, GFP_KERNEL);
937 res = ovl_do_getxattr(path, name, buf, res);
946 /* Copy up data of an inode which was copied up metadata only in the past. */
947 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
949 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
950 struct path upperpath;
952 char *capability = NULL;
955 ovl_path_upper(c->dentry, &upperpath);
956 if (WARN_ON(upperpath.dentry == NULL))
960 err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS,
966 err = ovl_copy_up_data(c, &upperpath);
971 * Writing to upper file will clear security.capability xattr. We
972 * don't want that to happen for normal copy-up operation.
975 err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
976 capability, cap_size, 0);
982 err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
986 ovl_set_upperdata(d_inode(c->dentry));
993 static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
997 DEFINE_DELAYED_CALL(done);
998 struct path parentpath;
999 struct ovl_copy_up_ctx ctx = {
1002 .workdir = ovl_workdir(dentry),
1005 if (WARN_ON(!ctx.workdir))
1008 ovl_path_lower(dentry, &ctx.lowerpath);
1009 err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
1010 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
1014 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
1017 ovl_path_upper(parent, &parentpath);
1018 ctx.destdir = parentpath.dentry;
1019 ctx.destname = dentry->d_name;
1021 err = vfs_getattr(&parentpath, &ctx.pstat,
1022 STATX_ATIME | STATX_MTIME,
1023 AT_STATX_SYNC_AS_STAT);
1028 /* maybe truncate regular file. this has no effect on dirs */
1029 if (flags & O_TRUNC)
1032 if (S_ISLNK(ctx.stat.mode)) {
1033 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
1034 if (IS_ERR(ctx.link))
1035 return PTR_ERR(ctx.link);
1038 err = ovl_copy_up_start(dentry, flags);
1039 /* err < 0: interrupted, err > 0: raced with another copy-up */
1040 if (unlikely(err)) {
1044 if (!ovl_dentry_upper(dentry))
1045 err = ovl_do_copy_up(&ctx);
1046 if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
1047 err = ovl_link_up(&ctx);
1048 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
1049 err = ovl_copy_up_meta_inode_data(&ctx);
1050 ovl_copy_up_end(dentry);
1052 do_delayed_call(&done);
1057 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
1060 const struct cred *old_cred;
1061 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
1064 * With NFS export, copy up can get called for a disconnected non-dir.
1065 * In this case, we will copy up lower inode to index dir without
1066 * linking it to upper dir.
1068 if (WARN_ON(disconnected && d_is_dir(dentry)))
1071 old_cred = ovl_override_creds(dentry->d_sb);
1073 struct dentry *next;
1074 struct dentry *parent = NULL;
1076 if (ovl_already_copied_up(dentry, flags))
1079 next = dget(dentry);
1080 /* find the topmost dentry not yet copied up */
1081 for (; !disconnected;) {
1082 parent = dget_parent(next);
1084 if (ovl_dentry_upper(parent))
1091 err = ovl_copy_up_one(parent, next, flags);
1096 revert_creds(old_cred);
1101 static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
1103 /* Copy up of disconnected dentry does not set upper alias */
1104 if (ovl_already_copied_up(dentry, flags))
1107 if (special_file(d_inode(dentry)->i_mode))
1110 if (!ovl_open_flags_need_copy_up(flags))
1116 int ovl_maybe_copy_up(struct dentry *dentry, int flags)
1120 if (ovl_open_need_copy_up(dentry, flags)) {
1121 err = ovl_want_write(dentry);
1123 err = ovl_copy_up_flags(dentry, flags);
1124 ovl_drop_write(dentry);
1131 int ovl_copy_up_with_data(struct dentry *dentry)
1133 return ovl_copy_up_flags(dentry, O_WRONLY);
1136 int ovl_copy_up(struct dentry *dentry)
1138 return ovl_copy_up_flags(dentry, 0);