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28 pr_warn("\"check_copy_up\" module option is obsolete\n");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 int ovl_copy_xattr(struct super_block *sb, const struct path *oldpath, struct dentry *new)
49 struct dentry *old = oldpath->dentry;
50 ssize_t list_size, size, value_size = 0;
51 char *buf, *name, *value = NULL;
55 if (!(old->d_inode->i_opflags & IOP_XATTR) ||
56 !(new->d_inode->i_opflags & IOP_XATTR))
59 list_size = vfs_listxattr(old, NULL, 0);
61 if (list_size == -EOPNOTSUPP)
66 buf = kvzalloc(list_size, GFP_KERNEL);
70 list_size = vfs_listxattr(old, buf, list_size);
76 for (name = buf; list_size; name += slen) {
77 slen = strnlen(name, list_size) + 1;
79 /* underlying fs providing us with an broken xattr list? */
80 if (WARN_ON(slen > list_size)) {
86 if (ovl_is_private_xattr(sb, name))
89 error = security_inode_copy_up_xattr(name);
90 if (error < 0 && error != -EOPNOTSUPP)
94 continue; /* Discard */
97 size = ovl_do_getxattr(oldpath, name, value, value_size);
99 size = ovl_do_getxattr(oldpath, name, NULL, 0);
106 if (size > value_size) {
109 new = kvmalloc(size, GFP_KERNEL);
120 error = ovl_do_setxattr(OVL_FS(sb), new, name, value, size, 0);
122 if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
125 /* Ignore failure to copy unknown xattrs */
135 static int ovl_copy_fileattr(struct inode *inode, const struct path *old,
136 const struct path *new)
138 struct fileattr oldfa = { .flags_valid = true };
139 struct fileattr newfa = { .flags_valid = true };
142 err = ovl_real_fileattr_get(old, &oldfa);
144 /* Ntfs-3g returns -EINVAL for "no fileattr support" */
145 if (err == -ENOTTY || err == -EINVAL)
147 pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
153 * We cannot set immutable and append-only flags on upper inode,
154 * because we would not be able to link upper inode to upper dir
155 * not set overlay private xattr on upper inode.
156 * Store these flags in overlay.protattr xattr instead.
158 if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
159 err = ovl_set_protattr(inode, new->dentry, &oldfa);
161 pr_warn_once("copying fileattr: no xattr on upper\n");
166 /* Don't bother copying flags if none are set */
167 if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK))
170 err = ovl_real_fileattr_get(new, &newfa);
173 * Returning an error if upper doesn't support fileattr will
174 * result in a regression, so revert to the old behavior.
176 if (err == -ENOTTY || err == -EINVAL) {
177 pr_warn_once("copying fileattr: no support on upper\n");
180 pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
185 BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL);
186 newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK;
187 newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK);
189 BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON);
190 newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK;
191 newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK);
193 return ovl_real_fileattr_set(new, &newfa);
196 static int ovl_copy_up_file(struct ovl_fs *ofs, struct dentry *dentry,
197 struct file *new_file, loff_t len)
199 struct path datapath;
200 struct file *old_file;
204 loff_t data_pos = -1;
206 bool skip_hole = false;
209 ovl_path_lowerdata(dentry, &datapath);
210 if (WARN_ON(datapath.dentry == NULL))
213 old_file = ovl_path_open(&datapath, O_LARGEFILE | O_RDONLY);
214 if (IS_ERR(old_file))
215 return PTR_ERR(old_file);
217 /* Try to use clone_file_range to clone up within the same fs */
218 cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
221 /* Couldn't clone, so now we try to copy the data */
223 /* Check if lower fs supports seek operation */
224 if (old_file->f_mode & FMODE_LSEEK)
228 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
234 if (signal_pending_state(TASK_KILLABLE, current)) {
240 * Fill zero for hole will cost unnecessary disk space
241 * and meanwhile slow down the copy-up speed, so we do
242 * an optimization for hole during copy-up, it relies
243 * on SEEK_DATA implementation in lower fs so if lower
244 * fs does not support it, copy-up will behave as before.
246 * Detail logic of hole detection as below:
247 * When we detect next data position is larger than current
248 * position we will skip that hole, otherwise we copy
249 * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
250 * it may not recognize all kind of holes and sometimes
251 * only skips partial of hole area. However, it will be
252 * enough for most of the use cases.
255 if (skip_hole && data_pos < old_pos) {
256 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
257 if (data_pos > old_pos) {
258 hole_len = data_pos - old_pos;
260 old_pos = new_pos = data_pos;
262 } else if (data_pos == -ENXIO) {
264 } else if (data_pos < 0) {
269 bytes = do_splice_direct(old_file, &old_pos,
271 this_len, SPLICE_F_MOVE);
276 WARN_ON(old_pos != new_pos);
280 if (!error && ovl_should_sync(ofs))
281 error = vfs_fsync(new_file, 0);
287 static int ovl_set_size(struct ovl_fs *ofs,
288 struct dentry *upperdentry, struct kstat *stat)
290 struct iattr attr = {
291 .ia_valid = ATTR_SIZE,
292 .ia_size = stat->size,
295 return ovl_do_notify_change(ofs, upperdentry, &attr);
298 static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry,
301 struct iattr attr = {
303 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
304 .ia_atime = stat->atime,
305 .ia_mtime = stat->mtime,
308 return ovl_do_notify_change(ofs, upperdentry, &attr);
311 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry,
316 if (!S_ISLNK(stat->mode)) {
317 struct iattr attr = {
318 .ia_valid = ATTR_MODE,
319 .ia_mode = stat->mode,
321 err = ovl_do_notify_change(ofs, upperdentry, &attr);
324 struct iattr attr = {
325 .ia_valid = ATTR_UID | ATTR_GID,
326 .ia_vfsuid = VFSUIDT_INIT(stat->uid),
327 .ia_vfsgid = VFSGIDT_INIT(stat->gid),
329 err = ovl_do_notify_change(ofs, upperdentry, &attr);
332 ovl_set_timestamps(ofs, upperdentry, stat);
337 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
342 int buflen = MAX_HANDLE_SZ;
343 uuid_t *uuid = &real->d_sb->s_uuid;
346 /* Make sure the real fid stays 32bit aligned */
347 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
348 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
350 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
352 return ERR_PTR(-ENOMEM);
355 * We encode a non-connectable file handle for non-dir, because we
356 * only need to find the lower inode number and we don't want to pay
357 * the price or reconnecting the dentry.
359 dwords = buflen >> 2;
360 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
361 buflen = (dwords << 2);
364 if (WARN_ON(fh_type < 0) ||
365 WARN_ON(buflen > MAX_HANDLE_SZ) ||
366 WARN_ON(fh_type == FILEID_INVALID))
369 fh->fb.version = OVL_FH_VERSION;
370 fh->fb.magic = OVL_FH_MAGIC;
371 fh->fb.type = fh_type;
372 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
374 * When we will want to decode an overlay dentry from this handle
375 * and all layers are on the same fs, if we get a disconncted real
376 * dentry when we decode fid, the only way to tell if we should assign
377 * it to upperdentry or to lowerstack is by checking this flag.
380 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
381 fh->fb.len = sizeof(fh->fb) + buflen;
382 if (ofs->config.uuid)
392 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
393 struct dentry *upper)
395 const struct ovl_fh *fh = NULL;
399 * When lower layer doesn't support export operations store a 'null' fh,
400 * so we can use the overlay.origin xattr to distignuish between a copy
401 * up and a pure upper inode.
403 if (ovl_can_decode_fh(lower->d_sb)) {
404 fh = ovl_encode_real_fh(ofs, lower, false);
410 * Do not fail when upper doesn't support xattrs.
412 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
413 fh ? fh->fb.len : 0, 0);
416 /* Ignore -EPERM from setting "user.*" on symlink/special */
417 return err == -EPERM ? 0 : err;
420 /* Store file handle of @upper dir in @index dir entry */
421 static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
422 struct dentry *index)
424 const struct ovl_fh *fh;
427 fh = ovl_encode_real_fh(ofs, upper, true);
431 err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
438 * Create and install index entry.
440 * Caller must hold i_mutex on indexdir.
442 static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
443 struct dentry *upper)
445 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
446 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
447 struct inode *dir = d_inode(indexdir);
448 struct dentry *index = NULL;
449 struct dentry *temp = NULL;
450 struct qstr name = { };
454 * For now this is only used for creating index entry for directories,
455 * because non-dir are copied up directly to index and then hardlinked
458 * TODO: implement create index for non-dir, so we can call it when
459 * encoding file handle for non-dir in case index does not exist.
461 if (WARN_ON(!d_is_dir(dentry)))
464 /* Directory not expected to be indexed before copy up */
465 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
468 err = ovl_get_index_name(ofs, origin, &name);
472 temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0));
477 err = ovl_set_upper_fh(ofs, upper, temp);
481 index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
483 err = PTR_ERR(index);
485 err = ovl_do_rename(ofs, dir, temp, dir, index, 0);
490 ovl_cleanup(ofs, dir, temp);
497 struct ovl_copy_up_ctx {
498 struct dentry *parent;
499 struct dentry *dentry;
500 struct path lowerpath;
504 struct dentry *destdir;
505 struct qstr destname;
506 struct dentry *workdir;
512 static int ovl_link_up(struct ovl_copy_up_ctx *c)
515 struct dentry *upper;
516 struct dentry *upperdir = ovl_dentry_upper(c->parent);
517 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
518 struct inode *udir = d_inode(upperdir);
520 /* Mark parent "impure" because it may now contain non-pure upper */
521 err = ovl_set_impure(c->parent, upperdir);
525 err = ovl_set_nlink_lower(c->dentry);
529 inode_lock_nested(udir, I_MUTEX_PARENT);
530 upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir,
531 c->dentry->d_name.len);
532 err = PTR_ERR(upper);
533 if (!IS_ERR(upper)) {
534 err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper);
538 /* Restore timestamps on parent (best effort) */
539 ovl_set_timestamps(ofs, upperdir, &c->pstat);
540 ovl_dentry_set_upper_alias(c->dentry);
547 err = ovl_set_nlink_upper(c->dentry);
552 static int ovl_copy_up_data(struct ovl_copy_up_ctx *c, const struct path *temp)
554 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
555 struct file *new_file;
558 if (!S_ISREG(c->stat.mode) || c->metacopy || !c->stat.size)
561 new_file = ovl_path_open(temp, O_LARGEFILE | O_WRONLY);
562 if (IS_ERR(new_file))
563 return PTR_ERR(new_file);
565 err = ovl_copy_up_file(ofs, c->dentry, new_file, c->stat.size);
571 static int ovl_copy_up_metadata(struct ovl_copy_up_ctx *c, struct dentry *temp)
573 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
574 struct inode *inode = d_inode(c->dentry);
575 struct path upperpath = { .mnt = ovl_upper_mnt(ofs), .dentry = temp };
578 err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp);
582 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK) {
584 * Copy the fileattr inode flags that are the source of already
587 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath);
593 * Store identifier of lower inode in upper inode xattr to
594 * allow lookup of the copy up origin inode.
596 * Don't set origin when we are breaking the association with a lower
600 err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
606 err = ovl_check_setxattr(ofs, temp, OVL_XATTR_METACOPY,
607 NULL, 0, -EOPNOTSUPP);
612 inode_lock(temp->d_inode);
613 if (S_ISREG(c->stat.mode))
614 err = ovl_set_size(ofs, temp, &c->stat);
616 err = ovl_set_attr(ofs, temp, &c->stat);
617 inode_unlock(temp->d_inode);
622 struct ovl_cu_creds {
623 const struct cred *old;
627 static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
631 cc->old = cc->new = NULL;
632 err = security_inode_copy_up(dentry, &cc->new);
637 cc->old = override_creds(cc->new);
642 static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
645 revert_creds(cc->old);
651 * Copyup using workdir to prepare temp file. Used when copying up directories,
652 * special files or when upper fs doesn't support O_TMPFILE.
654 static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
656 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
658 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
659 struct path path = { .mnt = ovl_upper_mnt(ofs) };
660 struct dentry *temp, *upper;
661 struct ovl_cu_creds cc;
663 struct ovl_cattr cattr = {
664 /* Can't properly set mode on creation because of the umask */
665 .mode = c->stat.mode & S_IFMT,
666 .rdev = c->stat.rdev,
670 /* workdir and destdir could be the same when copying up to indexdir */
672 if (lock_rename(c->workdir, c->destdir) != NULL)
675 err = ovl_prep_cu_creds(c->dentry, &cc);
679 temp = ovl_create_temp(ofs, c->workdir, &cattr);
680 ovl_revert_cu_creds(&cc);
687 * Copy up data first and then xattrs. Writing data after
688 * xattrs will remove security.capability xattr automatically.
691 err = ovl_copy_up_data(c, &path);
695 err = ovl_copy_up_metadata(c, temp);
699 if (S_ISDIR(c->stat.mode) && c->indexed) {
700 err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
705 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
707 err = PTR_ERR(upper);
711 err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0);
717 ovl_set_upperdata(d_inode(c->dentry));
718 inode = d_inode(c->dentry);
719 ovl_inode_update(inode, temp);
720 if (S_ISDIR(inode->i_mode))
721 ovl_set_flag(OVL_WHITEOUTS, inode);
723 unlock_rename(c->workdir, c->destdir);
728 ovl_cleanup(ofs, wdir, temp);
733 /* Copyup using O_TMPFILE which does not require cross dir locking */
734 static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
736 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
737 struct inode *udir = d_inode(c->destdir);
738 struct dentry *temp, *upper;
739 struct file *tmpfile;
740 struct ovl_cu_creds cc;
743 err = ovl_prep_cu_creds(c->dentry, &cc);
747 tmpfile = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode);
748 ovl_revert_cu_creds(&cc);
751 return PTR_ERR(tmpfile);
753 temp = tmpfile->f_path.dentry;
754 if (!c->metacopy && c->stat.size) {
755 err = ovl_copy_up_file(ofs, c->dentry, tmpfile, c->stat.size);
760 err = ovl_copy_up_metadata(c, temp);
764 inode_lock_nested(udir, I_MUTEX_PARENT);
766 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
768 err = PTR_ERR(upper);
769 if (!IS_ERR(upper)) {
770 err = ovl_do_link(ofs, temp, udir, upper);
779 ovl_set_upperdata(d_inode(c->dentry));
780 ovl_inode_update(d_inode(c->dentry), dget(temp));
788 * Copy up a single dentry
790 * All renames start with copy up of source if necessary. The actual
791 * rename will only proceed once the copy up was successful. Copy up uses
792 * upper parent i_mutex for exclusion. Since rename can change d_parent it
793 * is possible that the copy up will lock the old parent. At that point
794 * the file will have already been copied up anyway.
796 static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
799 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
800 bool to_index = false;
803 * Indexed non-dir is copied up directly to the index entry and then
804 * hardlinked to upper dir. Indexed dir is copied up to indexdir,
805 * then index entry is created and then copied up dir installed.
806 * Copying dir up to indexdir instead of workdir simplifies locking.
808 if (ovl_need_index(c->dentry)) {
810 if (S_ISDIR(c->stat.mode))
811 c->workdir = ovl_indexdir(c->dentry->d_sb);
816 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
820 c->destdir = ovl_indexdir(c->dentry->d_sb);
821 err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
824 } else if (WARN_ON(!c->parent)) {
825 /* Disconnected dentry must be copied up to index dir */
829 * Mark parent "impure" because it may now contain non-pure
832 err = ovl_set_impure(c->parent, c->destdir);
837 /* Should we copyup with O_TMPFILE or with workdir? */
838 if (S_ISREG(c->stat.mode) && ofs->tmpfile)
839 err = ovl_copy_up_tmpfile(c);
841 err = ovl_copy_up_workdir(c);
846 ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
849 /* Initialize nlink for copy up of disconnected dentry */
850 err = ovl_set_nlink_upper(c->dentry);
852 struct inode *udir = d_inode(c->destdir);
854 /* Restore timestamps on parent (best effort) */
856 ovl_set_timestamps(ofs, c->destdir, &c->pstat);
859 ovl_dentry_set_upper_alias(c->dentry);
864 kfree(c->destname.name);
868 static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
871 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
873 if (!ofs->config.metacopy)
879 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
885 static ssize_t ovl_getxattr_value(const struct path *path, char *name, char **value)
890 res = ovl_do_getxattr(path, name, NULL, 0);
891 if (res == -ENODATA || res == -EOPNOTSUPP)
895 buf = kzalloc(res, GFP_KERNEL);
899 res = ovl_do_getxattr(path, name, buf, res);
908 /* Copy up data of an inode which was copied up metadata only in the past. */
909 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
911 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
912 struct path upperpath;
914 char *capability = NULL;
917 ovl_path_upper(c->dentry, &upperpath);
918 if (WARN_ON(upperpath.dentry == NULL))
922 err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS,
928 err = ovl_copy_up_data(c, &upperpath);
933 * Writing to upper file will clear security.capability xattr. We
934 * don't want that to happen for normal copy-up operation.
937 err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
938 capability, cap_size, 0);
944 err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
948 ovl_set_upperdata(d_inode(c->dentry));
955 static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
959 DEFINE_DELAYED_CALL(done);
960 struct path parentpath;
961 struct ovl_copy_up_ctx ctx = {
964 .workdir = ovl_workdir(dentry),
967 if (WARN_ON(!ctx.workdir))
970 ovl_path_lower(dentry, &ctx.lowerpath);
971 err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
972 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
976 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
979 ovl_path_upper(parent, &parentpath);
980 ctx.destdir = parentpath.dentry;
981 ctx.destname = dentry->d_name;
983 err = vfs_getattr(&parentpath, &ctx.pstat,
984 STATX_ATIME | STATX_MTIME,
985 AT_STATX_SYNC_AS_STAT);
990 /* maybe truncate regular file. this has no effect on dirs */
994 if (S_ISLNK(ctx.stat.mode)) {
995 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
996 if (IS_ERR(ctx.link))
997 return PTR_ERR(ctx.link);
1000 err = ovl_copy_up_start(dentry, flags);
1001 /* err < 0: interrupted, err > 0: raced with another copy-up */
1002 if (unlikely(err)) {
1006 if (!ovl_dentry_upper(dentry))
1007 err = ovl_do_copy_up(&ctx);
1008 if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
1009 err = ovl_link_up(&ctx);
1010 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
1011 err = ovl_copy_up_meta_inode_data(&ctx);
1012 ovl_copy_up_end(dentry);
1014 do_delayed_call(&done);
1019 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
1022 const struct cred *old_cred;
1023 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
1026 * With NFS export, copy up can get called for a disconnected non-dir.
1027 * In this case, we will copy up lower inode to index dir without
1028 * linking it to upper dir.
1030 if (WARN_ON(disconnected && d_is_dir(dentry)))
1033 old_cred = ovl_override_creds(dentry->d_sb);
1035 struct dentry *next;
1036 struct dentry *parent = NULL;
1038 if (ovl_already_copied_up(dentry, flags))
1041 next = dget(dentry);
1042 /* find the topmost dentry not yet copied up */
1043 for (; !disconnected;) {
1044 parent = dget_parent(next);
1046 if (ovl_dentry_upper(parent))
1053 err = ovl_copy_up_one(parent, next, flags);
1058 revert_creds(old_cred);
1063 static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
1065 /* Copy up of disconnected dentry does not set upper alias */
1066 if (ovl_already_copied_up(dentry, flags))
1069 if (special_file(d_inode(dentry)->i_mode))
1072 if (!ovl_open_flags_need_copy_up(flags))
1078 int ovl_maybe_copy_up(struct dentry *dentry, int flags)
1082 if (ovl_open_need_copy_up(dentry, flags)) {
1083 err = ovl_want_write(dentry);
1085 err = ovl_copy_up_flags(dentry, flags);
1086 ovl_drop_write(dentry);
1093 int ovl_copy_up_with_data(struct dentry *dentry)
1095 return ovl_copy_up_flags(dentry, O_WRONLY);
1098 int ovl_copy_up(struct dentry *dentry)
1100 return ovl_copy_up_flags(dentry, 0);