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28 pr_warn("\"check_copy_up\" module option is obsolete\n");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, 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, struct path *old,
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_data(struct ovl_fs *ofs, struct path *old,
197 struct path *new, loff_t len)
199 struct file *old_file;
200 struct file *new_file;
204 loff_t data_pos = -1;
206 bool skip_hole = false;
212 old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY);
213 if (IS_ERR(old_file))
214 return PTR_ERR(old_file);
216 new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY);
217 if (IS_ERR(new_file)) {
218 error = PTR_ERR(new_file);
222 /* Try to use clone_file_range to clone up within the same fs */
223 cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
226 /* Couldn't clone, so now we try to copy the data */
228 /* Check if lower fs supports seek operation */
229 if (old_file->f_mode & FMODE_LSEEK &&
230 old_file->f_op->llseek)
234 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
240 if (signal_pending_state(TASK_KILLABLE, current)) {
246 * Fill zero for hole will cost unnecessary disk space
247 * and meanwhile slow down the copy-up speed, so we do
248 * an optimization for hole during copy-up, it relies
249 * on SEEK_DATA implementation in lower fs so if lower
250 * fs does not support it, copy-up will behave as before.
252 * Detail logic of hole detection as below:
253 * When we detect next data position is larger than current
254 * position we will skip that hole, otherwise we copy
255 * data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually,
256 * it may not recognize all kind of holes and sometimes
257 * only skips partial of hole area. However, it will be
258 * enough for most of the use cases.
261 if (skip_hole && data_pos < old_pos) {
262 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
263 if (data_pos > old_pos) {
264 hole_len = data_pos - old_pos;
266 old_pos = new_pos = data_pos;
268 } else if (data_pos == -ENXIO) {
270 } else if (data_pos < 0) {
275 bytes = do_splice_direct(old_file, &old_pos,
277 this_len, SPLICE_F_MOVE);
282 WARN_ON(old_pos != new_pos);
287 if (!error && ovl_should_sync(ofs))
288 error = vfs_fsync(new_file, 0);
295 static int ovl_set_size(struct ovl_fs *ofs,
296 struct dentry *upperdentry, struct kstat *stat)
298 struct iattr attr = {
299 .ia_valid = ATTR_SIZE,
300 .ia_size = stat->size,
303 return ovl_do_notify_change(ofs, upperdentry, &attr);
306 static int ovl_set_timestamps(struct ovl_fs *ofs, struct dentry *upperdentry,
309 struct iattr attr = {
311 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
312 .ia_atime = stat->atime,
313 .ia_mtime = stat->mtime,
316 return ovl_do_notify_change(ofs, upperdentry, &attr);
319 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upperdentry,
324 if (!S_ISLNK(stat->mode)) {
325 struct iattr attr = {
326 .ia_valid = ATTR_MODE,
327 .ia_mode = stat->mode,
329 err = ovl_do_notify_change(ofs, upperdentry, &attr);
332 struct iattr attr = {
333 .ia_valid = ATTR_UID | ATTR_GID,
337 err = ovl_do_notify_change(ofs, upperdentry, &attr);
340 ovl_set_timestamps(ofs, upperdentry, stat);
345 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
350 int buflen = MAX_HANDLE_SZ;
351 uuid_t *uuid = &real->d_sb->s_uuid;
354 /* Make sure the real fid stays 32bit aligned */
355 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
356 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
358 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
360 return ERR_PTR(-ENOMEM);
363 * We encode a non-connectable file handle for non-dir, because we
364 * only need to find the lower inode number and we don't want to pay
365 * the price or reconnecting the dentry.
367 dwords = buflen >> 2;
368 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
369 buflen = (dwords << 2);
372 if (WARN_ON(fh_type < 0) ||
373 WARN_ON(buflen > MAX_HANDLE_SZ) ||
374 WARN_ON(fh_type == FILEID_INVALID))
377 fh->fb.version = OVL_FH_VERSION;
378 fh->fb.magic = OVL_FH_MAGIC;
379 fh->fb.type = fh_type;
380 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
382 * When we will want to decode an overlay dentry from this handle
383 * and all layers are on the same fs, if we get a disconncted real
384 * dentry when we decode fid, the only way to tell if we should assign
385 * it to upperdentry or to lowerstack is by checking this flag.
388 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
389 fh->fb.len = sizeof(fh->fb) + buflen;
390 if (ofs->config.uuid)
400 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
401 struct dentry *upper)
403 const struct ovl_fh *fh = NULL;
407 * When lower layer doesn't support export operations store a 'null' fh,
408 * so we can use the overlay.origin xattr to distignuish between a copy
409 * up and a pure upper inode.
411 if (ovl_can_decode_fh(lower->d_sb)) {
412 fh = ovl_encode_real_fh(ofs, lower, false);
418 * Do not fail when upper doesn't support xattrs.
420 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
421 fh ? fh->fb.len : 0, 0);
424 /* Ignore -EPERM from setting "user.*" on symlink/special */
425 return err == -EPERM ? 0 : err;
428 /* Store file handle of @upper dir in @index dir entry */
429 static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
430 struct dentry *index)
432 const struct ovl_fh *fh;
435 fh = ovl_encode_real_fh(ofs, upper, true);
439 err = ovl_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
446 * Create and install index entry.
448 * Caller must hold i_mutex on indexdir.
450 static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
451 struct dentry *upper)
453 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
454 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
455 struct inode *dir = d_inode(indexdir);
456 struct dentry *index = NULL;
457 struct dentry *temp = NULL;
458 struct qstr name = { };
462 * For now this is only used for creating index entry for directories,
463 * because non-dir are copied up directly to index and then hardlinked
466 * TODO: implement create index for non-dir, so we can call it when
467 * encoding file handle for non-dir in case index does not exist.
469 if (WARN_ON(!d_is_dir(dentry)))
472 /* Directory not expected to be indexed before copy up */
473 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
476 err = ovl_get_index_name(ofs, origin, &name);
480 temp = ovl_create_temp(ofs, indexdir, OVL_CATTR(S_IFDIR | 0));
485 err = ovl_set_upper_fh(ofs, upper, temp);
489 index = ovl_lookup_upper(ofs, name.name, indexdir, name.len);
491 err = PTR_ERR(index);
493 err = ovl_do_rename(ofs, dir, temp, dir, index, 0);
498 ovl_cleanup(ofs, dir, temp);
505 struct ovl_copy_up_ctx {
506 struct dentry *parent;
507 struct dentry *dentry;
508 struct path lowerpath;
512 struct dentry *destdir;
513 struct qstr destname;
514 struct dentry *workdir;
520 static int ovl_link_up(struct ovl_copy_up_ctx *c)
523 struct dentry *upper;
524 struct dentry *upperdir = ovl_dentry_upper(c->parent);
525 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
526 struct inode *udir = d_inode(upperdir);
528 /* Mark parent "impure" because it may now contain non-pure upper */
529 err = ovl_set_impure(c->parent, upperdir);
533 err = ovl_set_nlink_lower(c->dentry);
537 inode_lock_nested(udir, I_MUTEX_PARENT);
538 upper = ovl_lookup_upper(ofs, c->dentry->d_name.name, upperdir,
539 c->dentry->d_name.len);
540 err = PTR_ERR(upper);
541 if (!IS_ERR(upper)) {
542 err = ovl_do_link(ofs, ovl_dentry_upper(c->dentry), udir, upper);
546 /* Restore timestamps on parent (best effort) */
547 ovl_set_timestamps(ofs, upperdir, &c->pstat);
548 ovl_dentry_set_upper_alias(c->dentry);
555 err = ovl_set_nlink_upper(c->dentry);
560 static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
562 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
563 struct inode *inode = d_inode(c->dentry);
564 struct path upperpath, datapath;
567 ovl_path_upper(c->dentry, &upperpath);
568 if (WARN_ON(upperpath.dentry != NULL))
571 upperpath.dentry = temp;
574 * Copy up data first and then xattrs. Writing data after
575 * xattrs will remove security.capability xattr automatically.
577 if (S_ISREG(c->stat.mode) && !c->metacopy) {
578 ovl_path_lowerdata(c->dentry, &datapath);
579 err = ovl_copy_up_data(ofs, &datapath, &upperpath,
585 err = ovl_copy_xattr(c->dentry->d_sb, &c->lowerpath, temp);
589 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK) {
591 * Copy the fileattr inode flags that are the source of already
594 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath);
600 * Store identifier of lower inode in upper inode xattr to
601 * allow lookup of the copy up origin inode.
603 * Don't set origin when we are breaking the association with a lower
607 err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
613 err = ovl_check_setxattr(ofs, temp, OVL_XATTR_METACOPY,
614 NULL, 0, -EOPNOTSUPP);
619 inode_lock(temp->d_inode);
620 if (S_ISREG(c->stat.mode))
621 err = ovl_set_size(ofs, temp, &c->stat);
623 err = ovl_set_attr(ofs, temp, &c->stat);
624 inode_unlock(temp->d_inode);
629 struct ovl_cu_creds {
630 const struct cred *old;
634 static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
638 cc->old = cc->new = NULL;
639 err = security_inode_copy_up(dentry, &cc->new);
644 cc->old = override_creds(cc->new);
649 static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
652 revert_creds(cc->old);
658 * Copyup using workdir to prepare temp file. Used when copying up directories,
659 * special files or when upper fs doesn't support O_TMPFILE.
661 static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
663 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
665 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
666 struct dentry *temp, *upper;
667 struct ovl_cu_creds cc;
669 struct ovl_cattr cattr = {
670 /* Can't properly set mode on creation because of the umask */
671 .mode = c->stat.mode & S_IFMT,
672 .rdev = c->stat.rdev,
676 /* workdir and destdir could be the same when copying up to indexdir */
678 if (lock_rename(c->workdir, c->destdir) != NULL)
681 err = ovl_prep_cu_creds(c->dentry, &cc);
685 temp = ovl_create_temp(ofs, c->workdir, &cattr);
686 ovl_revert_cu_creds(&cc);
692 err = ovl_copy_up_inode(c, temp);
696 if (S_ISDIR(c->stat.mode) && c->indexed) {
697 err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
702 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
704 err = PTR_ERR(upper);
708 err = ovl_do_rename(ofs, wdir, temp, udir, upper, 0);
714 ovl_set_upperdata(d_inode(c->dentry));
715 inode = d_inode(c->dentry);
716 ovl_inode_update(inode, temp);
717 if (S_ISDIR(inode->i_mode))
718 ovl_set_flag(OVL_WHITEOUTS, inode);
720 unlock_rename(c->workdir, c->destdir);
725 ovl_cleanup(ofs, wdir, temp);
730 /* Copyup using O_TMPFILE which does not require cross dir locking */
731 static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
733 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
734 struct inode *udir = d_inode(c->destdir);
735 struct dentry *temp, *upper;
736 struct ovl_cu_creds cc;
739 err = ovl_prep_cu_creds(c->dentry, &cc);
743 temp = ovl_do_tmpfile(ofs, c->workdir, c->stat.mode);
744 ovl_revert_cu_creds(&cc);
747 return PTR_ERR(temp);
749 err = ovl_copy_up_inode(c, temp);
753 inode_lock_nested(udir, I_MUTEX_PARENT);
755 upper = ovl_lookup_upper(ofs, c->destname.name, c->destdir,
757 err = PTR_ERR(upper);
758 if (!IS_ERR(upper)) {
759 err = ovl_do_link(ofs, temp, udir, upper);
768 ovl_set_upperdata(d_inode(c->dentry));
769 ovl_inode_update(d_inode(c->dentry), temp);
779 * Copy up a single dentry
781 * All renames start with copy up of source if necessary. The actual
782 * rename will only proceed once the copy up was successful. Copy up uses
783 * upper parent i_mutex for exclusion. Since rename can change d_parent it
784 * is possible that the copy up will lock the old parent. At that point
785 * the file will have already been copied up anyway.
787 static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
790 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
791 bool to_index = false;
794 * Indexed non-dir is copied up directly to the index entry and then
795 * hardlinked to upper dir. Indexed dir is copied up to indexdir,
796 * then index entry is created and then copied up dir installed.
797 * Copying dir up to indexdir instead of workdir simplifies locking.
799 if (ovl_need_index(c->dentry)) {
801 if (S_ISDIR(c->stat.mode))
802 c->workdir = ovl_indexdir(c->dentry->d_sb);
807 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
811 c->destdir = ovl_indexdir(c->dentry->d_sb);
812 err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
815 } else if (WARN_ON(!c->parent)) {
816 /* Disconnected dentry must be copied up to index dir */
820 * Mark parent "impure" because it may now contain non-pure
823 err = ovl_set_impure(c->parent, c->destdir);
828 /* Should we copyup with O_TMPFILE or with workdir? */
829 if (S_ISREG(c->stat.mode) && ofs->tmpfile)
830 err = ovl_copy_up_tmpfile(c);
832 err = ovl_copy_up_workdir(c);
837 ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
840 /* Initialize nlink for copy up of disconnected dentry */
841 err = ovl_set_nlink_upper(c->dentry);
843 struct inode *udir = d_inode(c->destdir);
845 /* Restore timestamps on parent (best effort) */
847 ovl_set_timestamps(ofs, c->destdir, &c->pstat);
850 ovl_dentry_set_upper_alias(c->dentry);
855 kfree(c->destname.name);
859 static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
862 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
864 if (!ofs->config.metacopy)
870 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
876 static ssize_t ovl_getxattr_value(struct path *path, char *name, char **value)
881 res = ovl_do_getxattr(path, name, NULL, 0);
882 if (res == -ENODATA || res == -EOPNOTSUPP)
886 buf = kzalloc(res, GFP_KERNEL);
890 res = ovl_do_getxattr(path, name, buf, res);
899 /* Copy up data of an inode which was copied up metadata only in the past. */
900 static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
902 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
903 struct path upperpath, datapath;
905 char *capability = NULL;
908 ovl_path_upper(c->dentry, &upperpath);
909 if (WARN_ON(upperpath.dentry == NULL))
912 ovl_path_lowerdata(c->dentry, &datapath);
913 if (WARN_ON(datapath.dentry == NULL))
917 err = cap_size = ovl_getxattr_value(&upperpath, XATTR_NAME_CAPS,
923 err = ovl_copy_up_data(ofs, &datapath, &upperpath, c->stat.size);
928 * Writing to upper file will clear security.capability xattr. We
929 * don't want that to happen for normal copy-up operation.
932 err = ovl_do_setxattr(ofs, upperpath.dentry, XATTR_NAME_CAPS,
933 capability, cap_size, 0);
939 err = ovl_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
943 ovl_set_upperdata(d_inode(c->dentry));
950 static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
954 DEFINE_DELAYED_CALL(done);
955 struct path parentpath;
956 struct ovl_copy_up_ctx ctx = {
959 .workdir = ovl_workdir(dentry),
962 if (WARN_ON(!ctx.workdir))
965 ovl_path_lower(dentry, &ctx.lowerpath);
966 err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
967 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
971 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
974 ovl_path_upper(parent, &parentpath);
975 ctx.destdir = parentpath.dentry;
976 ctx.destname = dentry->d_name;
978 err = vfs_getattr(&parentpath, &ctx.pstat,
979 STATX_ATIME | STATX_MTIME,
980 AT_STATX_SYNC_AS_STAT);
985 /* maybe truncate regular file. this has no effect on dirs */
989 if (S_ISLNK(ctx.stat.mode)) {
990 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
991 if (IS_ERR(ctx.link))
992 return PTR_ERR(ctx.link);
995 err = ovl_copy_up_start(dentry, flags);
996 /* err < 0: interrupted, err > 0: raced with another copy-up */
1001 if (!ovl_dentry_upper(dentry))
1002 err = ovl_do_copy_up(&ctx);
1003 if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
1004 err = ovl_link_up(&ctx);
1005 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
1006 err = ovl_copy_up_meta_inode_data(&ctx);
1007 ovl_copy_up_end(dentry);
1009 do_delayed_call(&done);
1014 static int ovl_copy_up_flags(struct dentry *dentry, int flags)
1017 const struct cred *old_cred;
1018 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
1021 * With NFS export, copy up can get called for a disconnected non-dir.
1022 * In this case, we will copy up lower inode to index dir without
1023 * linking it to upper dir.
1025 if (WARN_ON(disconnected && d_is_dir(dentry)))
1028 old_cred = ovl_override_creds(dentry->d_sb);
1030 struct dentry *next;
1031 struct dentry *parent = NULL;
1033 if (ovl_already_copied_up(dentry, flags))
1036 next = dget(dentry);
1037 /* find the topmost dentry not yet copied up */
1038 for (; !disconnected;) {
1039 parent = dget_parent(next);
1041 if (ovl_dentry_upper(parent))
1048 err = ovl_copy_up_one(parent, next, flags);
1053 revert_creds(old_cred);
1058 static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
1060 /* Copy up of disconnected dentry does not set upper alias */
1061 if (ovl_already_copied_up(dentry, flags))
1064 if (special_file(d_inode(dentry)->i_mode))
1067 if (!ovl_open_flags_need_copy_up(flags))
1073 int ovl_maybe_copy_up(struct dentry *dentry, int flags)
1077 if (ovl_open_need_copy_up(dentry, flags)) {
1078 err = ovl_want_write(dentry);
1080 err = ovl_copy_up_flags(dentry, flags);
1081 ovl_drop_write(dentry);
1088 int ovl_copy_up_with_data(struct dentry *dentry)
1090 return ovl_copy_up_flags(dentry, O_WRONLY);
1093 int ovl_copy_up(struct dentry *dentry)
1095 return ovl_copy_up_flags(dentry, 0);