[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/fs/overlayfs/dir.c b/src/kernel/linux/v4.14/fs/overlayfs/dir.c
new file mode 100644
index 0000000..8c56170
--- /dev/null
+++ b/src/kernel/linux/v4.14/fs/overlayfs/dir.c
@@ -0,0 +1,1117 @@
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/xattr.h>
+#include <linux/security.h>
+#include <linux/cred.h>
+#include <linux/module.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/atomic.h>
+#include <linux/ratelimit.h>
+#include "overlayfs.h"
+
+static unsigned short ovl_redirect_max = 256;
+module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
+MODULE_PARM_DESC(ovl_redirect_max,
+ "Maximum length of absolute redirect xattr value");
+
+int ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
+{
+ int err;
+
+ dget(wdentry);
+ if (d_is_dir(wdentry))
+ err = ovl_do_rmdir(wdir, wdentry);
+ else
+ err = ovl_do_unlink(wdir, wdentry);
+ dput(wdentry);
+
+ if (err) {
+ pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
+ wdentry, err);
+ }
+
+ return err;
+}
+
+struct dentry *ovl_lookup_temp(struct dentry *workdir)
+{
+ struct dentry *temp;
+ char name[20];
+ static atomic_t temp_id = ATOMIC_INIT(0);
+
+ /* counter is allowed to wrap, since temp dentries are ephemeral */
+ snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
+
+ temp = lookup_one_len(name, workdir, strlen(name));
+ if (!IS_ERR(temp) && temp->d_inode) {
+ pr_err("overlayfs: workdir/%s already exists\n", name);
+ dput(temp);
+ temp = ERR_PTR(-EIO);
+ }
+
+ return temp;
+}
+
+/* caller holds i_mutex on workdir */
+static struct dentry *ovl_whiteout(struct dentry *workdir,
+ struct dentry *dentry)
+{
+ int err;
+ struct dentry *whiteout;
+ struct inode *wdir = workdir->d_inode;
+
+ whiteout = ovl_lookup_temp(workdir);
+ if (IS_ERR(whiteout))
+ return whiteout;
+
+ err = ovl_do_whiteout(wdir, whiteout);
+ if (err) {
+ dput(whiteout);
+ whiteout = ERR_PTR(err);
+ }
+
+ return whiteout;
+}
+
+int ovl_create_real(struct inode *dir, struct dentry *newdentry,
+ struct cattr *attr, struct dentry *hardlink, bool debug)
+{
+ int err;
+
+ if (newdentry->d_inode)
+ return -ESTALE;
+
+ if (hardlink) {
+ err = ovl_do_link(hardlink, dir, newdentry, debug);
+ } else {
+ switch (attr->mode & S_IFMT) {
+ case S_IFREG:
+ err = ovl_do_create(dir, newdentry, attr->mode, debug);
+ break;
+
+ case S_IFDIR:
+ err = ovl_do_mkdir(dir, newdentry, attr->mode, debug);
+ break;
+
+ case S_IFCHR:
+ case S_IFBLK:
+ case S_IFIFO:
+ case S_IFSOCK:
+ err = ovl_do_mknod(dir, newdentry,
+ attr->mode, attr->rdev, debug);
+ break;
+
+ case S_IFLNK:
+ err = ovl_do_symlink(dir, newdentry, attr->link, debug);
+ break;
+
+ default:
+ err = -EPERM;
+ }
+ }
+ if (!err && WARN_ON(!newdentry->d_inode)) {
+ /*
+ * Not quite sure if non-instantiated dentry is legal or not.
+ * VFS doesn't seem to care so check and warn here.
+ */
+ err = -ENOENT;
+ }
+ return err;
+}
+
+static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
+ int xerr)
+{
+ int err;
+
+ err = ovl_check_setxattr(dentry, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
+ if (!err)
+ ovl_dentry_set_opaque(dentry);
+
+ return err;
+}
+
+static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
+{
+ /*
+ * Fail with -EIO when trying to create opaque dir and upper doesn't
+ * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to
+ * return a specific error for noxattr case.
+ */
+ return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
+}
+
+/* Common operations required to be done after creation of file on upper */
+static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
+ struct dentry *newdentry, bool hardlink)
+{
+ ovl_dentry_version_inc(dentry->d_parent, false);
+ ovl_dentry_set_upper_alias(dentry);
+ if (!hardlink) {
+ ovl_inode_update(inode, newdentry);
+ ovl_copyattr(newdentry->d_inode, inode);
+ } else {
+ WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
+ dput(newdentry);
+ inc_nlink(inode);
+ }
+ d_instantiate(dentry, inode);
+ /* Force lookup of new upper hardlink to find its lower */
+ if (hardlink)
+ d_drop(dentry);
+}
+
+static bool ovl_type_merge(struct dentry *dentry)
+{
+ return OVL_TYPE_MERGE(ovl_path_type(dentry));
+}
+
+static bool ovl_type_origin(struct dentry *dentry)
+{
+ return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
+}
+
+static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
+ struct cattr *attr, struct dentry *hardlink)
+{
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *newdentry;
+ int err;
+
+ if (!hardlink && !IS_POSIXACL(udir))
+ attr->mode &= ~current_umask();
+
+ inode_lock_nested(udir, I_MUTEX_PARENT);
+ newdentry = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_unlock;
+ err = ovl_create_real(udir, newdentry, attr, hardlink, false);
+ if (err)
+ goto out_dput;
+
+ if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) {
+ /* Setting opaque here is just an optimization, allow to fail */
+ ovl_set_opaque(dentry, newdentry);
+ }
+
+ ovl_instantiate(dentry, inode, newdentry, !!hardlink);
+ newdentry = NULL;
+out_dput:
+ dput(newdentry);
+out_unlock:
+ inode_unlock(udir);
+ return err;
+}
+
+static struct dentry *ovl_clear_empty(struct dentry *dentry,
+ struct list_head *list)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct path upperpath;
+ struct dentry *upper;
+ struct dentry *opaquedir;
+ struct kstat stat;
+ int err;
+
+ if (WARN_ON(!workdir))
+ return ERR_PTR(-EROFS);
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out;
+
+ ovl_path_upper(dentry, &upperpath);
+ err = vfs_getattr(&upperpath, &stat,
+ STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
+ if (err)
+ goto out_unlock;
+
+ err = -ESTALE;
+ if (!S_ISDIR(stat.mode))
+ goto out_unlock;
+ upper = upperpath.dentry;
+ if (upper->d_parent->d_inode != udir)
+ goto out_unlock;
+
+ opaquedir = ovl_lookup_temp(workdir);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out_unlock;
+
+ err = ovl_create_real(wdir, opaquedir,
+ &(struct cattr){.mode = stat.mode}, NULL, true);
+ if (err)
+ goto out_dput;
+
+ err = ovl_copy_xattr(upper, opaquedir);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_set_opaque(dentry, opaquedir);
+ if (err)
+ goto out_cleanup;
+
+ inode_lock(opaquedir->d_inode);
+ err = ovl_set_attr(opaquedir, &stat);
+ inode_unlock(opaquedir->d_inode);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
+ if (err)
+ goto out_cleanup;
+
+ ovl_cleanup_whiteouts(upper, list);
+ ovl_cleanup(wdir, upper);
+ unlock_rename(workdir, upperdir);
+
+ /* dentry's upper doesn't match now, get rid of it */
+ d_drop(dentry);
+
+ return opaquedir;
+
+out_cleanup:
+ ovl_cleanup(wdir, opaquedir);
+out_dput:
+ dput(opaquedir);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out:
+ return ERR_PTR(err);
+}
+
+static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
+{
+ int err;
+ struct dentry *ret = NULL;
+ enum ovl_path_type type = ovl_path_type(dentry);
+ LIST_HEAD(list);
+
+ err = ovl_check_empty_dir(dentry, &list);
+ if (err) {
+ ret = ERR_PTR(err);
+ goto out_free;
+ }
+
+ /*
+ * When removing an empty opaque directory, then it makes no sense to
+ * replace it with an exact replica of itself.
+ *
+ * If no upperdentry then skip clearing whiteouts.
+ *
+ * Can race with copy-up, since we don't hold the upperdir mutex.
+ * Doesn't matter, since copy-up can't create a non-empty directory
+ * from an empty one.
+ */
+ if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type))
+ ret = ovl_clear_empty(dentry, &list);
+
+out_free:
+ ovl_cache_free(&list);
+
+ return ret;
+}
+
+static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
+ const struct posix_acl *acl)
+{
+ void *buffer;
+ size_t size;
+ int err;
+
+ if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
+ return 0;
+
+ size = posix_acl_to_xattr(NULL, acl, NULL, 0);
+ buffer = kmalloc(size, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+ err = size;
+ if (err < 0)
+ goto out_free;
+
+ err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
+out_free:
+ kfree(buffer);
+ return err;
+}
+
+static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
+ struct cattr *cattr,
+ struct dentry *hardlink)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *upper;
+ struct dentry *newdentry;
+ int err;
+ struct posix_acl *acl, *default_acl;
+
+ if (WARN_ON(!workdir))
+ return -EROFS;
+
+ if (!hardlink) {
+ err = posix_acl_create(dentry->d_parent->d_inode,
+ &cattr->mode, &default_acl, &acl);
+ if (err)
+ return err;
+ }
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out;
+
+ newdentry = ovl_lookup_temp(workdir);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_unlock;
+
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto out_dput;
+
+ err = -ESTALE;
+ if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper)))
+ goto out_dput2;
+
+ err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
+ if (err)
+ goto out_dput2;
+
+ /*
+ * mode could have been mutilated due to umask (e.g. sgid directory)
+ */
+ if (!hardlink &&
+ !S_ISLNK(cattr->mode) &&
+ newdentry->d_inode->i_mode != cattr->mode) {
+ struct iattr attr = {
+ .ia_valid = ATTR_MODE,
+ .ia_mode = cattr->mode,
+ };
+ inode_lock(newdentry->d_inode);
+ err = notify_change(newdentry, &attr, NULL);
+ inode_unlock(newdentry->d_inode);
+ if (err)
+ goto out_cleanup;
+ }
+ if (!hardlink) {
+ err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
+ acl);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
+ default_acl);
+ if (err)
+ goto out_cleanup;
+ }
+
+ if (!hardlink && S_ISDIR(cattr->mode)) {
+ err = ovl_set_opaque(dentry, newdentry);
+ if (err)
+ goto out_cleanup;
+
+ err = ovl_do_rename(wdir, newdentry, udir, upper,
+ RENAME_EXCHANGE);
+ if (err)
+ goto out_cleanup;
+
+ ovl_cleanup(wdir, upper);
+ } else {
+ err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
+ if (err)
+ goto out_cleanup;
+ }
+ ovl_instantiate(dentry, inode, newdentry, !!hardlink);
+ newdentry = NULL;
+out_dput2:
+ dput(upper);
+out_dput:
+ dput(newdentry);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out:
+ if (!hardlink) {
+ posix_acl_release(acl);
+ posix_acl_release(default_acl);
+ }
+ return err;
+
+out_cleanup:
+ ovl_cleanup(wdir, newdentry);
+ goto out_dput2;
+}
+
+static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
+ struct cattr *attr, struct dentry *hardlink,
+ bool origin)
+{
+ int err;
+ const struct cred *old_cred;
+ struct cred *override_cred;
+ struct dentry *parent = dentry->d_parent;
+
+ err = ovl_copy_up(parent);
+ if (err)
+ return err;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+
+ /*
+ * When linking a file with copy up origin into a new parent, mark the
+ * new parent dir "impure".
+ */
+ if (origin) {
+ err = ovl_set_impure(parent, ovl_dentry_upper(parent));
+ if (err)
+ goto out_revert_creds;
+ }
+
+ err = -ENOMEM;
+ override_cred = prepare_creds();
+ if (override_cred) {
+ override_cred->fsuid = inode->i_uid;
+ override_cred->fsgid = inode->i_gid;
+ if (!hardlink) {
+ err = security_dentry_create_files_as(dentry,
+ attr->mode, &dentry->d_name, old_cred,
+ override_cred);
+ if (err) {
+ put_cred(override_cred);
+ goto out_revert_creds;
+ }
+ }
+ put_cred(override_creds(override_cred));
+ put_cred(override_cred);
+
+ if (!ovl_dentry_is_whiteout(dentry))
+ err = ovl_create_upper(dentry, inode, attr,
+ hardlink);
+ else
+ err = ovl_create_over_whiteout(dentry, inode, attr,
+ hardlink);
+ }
+out_revert_creds:
+ revert_creds(old_cred);
+ if (!err) {
+ struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
+
+ WARN_ON(inode->i_mode != realinode->i_mode);
+ WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
+ WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
+ }
+ return err;
+}
+
+static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
+ const char *link)
+{
+ int err;
+ struct inode *inode;
+ struct cattr attr = {
+ .rdev = rdev,
+ .link = link,
+ };
+
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
+ err = -ENOMEM;
+ inode = ovl_new_inode(dentry->d_sb, mode, rdev);
+ if (!inode)
+ goto out_drop_write;
+
+ inode_init_owner(inode, dentry->d_parent->d_inode, mode);
+ attr.mode = inode->i_mode;
+
+ err = ovl_create_or_link(dentry, inode, &attr, NULL, false);
+ if (err)
+ iput(inode);
+
+out_drop_write:
+ ovl_drop_write(dentry);
+out:
+ return err;
+}
+
+static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+ bool excl)
+{
+ return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
+}
+
+static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+{
+ return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
+}
+
+static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+ dev_t rdev)
+{
+ /* Don't allow creation of "whiteout" on overlay */
+ if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
+ return -EPERM;
+
+ return ovl_create_object(dentry, mode, rdev, NULL);
+}
+
+static int ovl_symlink(struct inode *dir, struct dentry *dentry,
+ const char *link)
+{
+ return ovl_create_object(dentry, S_IFLNK, 0, link);
+}
+
+static int ovl_link(struct dentry *old, struct inode *newdir,
+ struct dentry *new)
+{
+ int err;
+ bool locked = false;
+ struct inode *inode;
+
+ err = ovl_want_write(old);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(old);
+ if (err)
+ goto out_drop_write;
+
+ err = ovl_copy_up(new->d_parent);
+ if (err)
+ goto out_drop_write;
+
+
+ err = ovl_nlink_start(old, &locked);
+ if (err)
+ goto out_drop_write;
+
+ inode = d_inode(old);
+ ihold(inode);
+
+ err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old),
+ ovl_type_origin(old));
+ if (err)
+ iput(inode);
+
+ ovl_nlink_end(old, locked);
+out_drop_write:
+ ovl_drop_write(old);
+out:
+ return err;
+}
+
+static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
+{
+ return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper);
+}
+
+static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
+{
+ struct dentry *workdir = ovl_workdir(dentry);
+ struct inode *wdir = workdir->d_inode;
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *udir = upperdir->d_inode;
+ struct dentry *whiteout;
+ struct dentry *upper;
+ struct dentry *opaquedir = NULL;
+ int err;
+ int flags = 0;
+
+ if (WARN_ON(!workdir))
+ return -EROFS;
+
+ if (is_dir) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ }
+
+ err = ovl_lock_rename_workdir(workdir, upperdir);
+ if (err)
+ goto out_dput;
+
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto out_unlock;
+
+ err = -ESTALE;
+ if ((opaquedir && upper != opaquedir) ||
+ (!opaquedir && ovl_dentry_upper(dentry) &&
+ !ovl_matches_upper(dentry, upper))) {
+ goto out_dput_upper;
+ }
+
+ whiteout = ovl_whiteout(workdir, dentry);
+ err = PTR_ERR(whiteout);
+ if (IS_ERR(whiteout))
+ goto out_dput_upper;
+
+ if (d_is_dir(upper))
+ flags = RENAME_EXCHANGE;
+
+ err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
+ if (err)
+ goto kill_whiteout;
+ if (flags)
+ ovl_cleanup(wdir, upper);
+
+ ovl_dentry_version_inc(dentry->d_parent, true);
+out_d_drop:
+ d_drop(dentry);
+ dput(whiteout);
+out_dput_upper:
+ dput(upper);
+out_unlock:
+ unlock_rename(workdir, upperdir);
+out_dput:
+ dput(opaquedir);
+out:
+ return err;
+
+kill_whiteout:
+ ovl_cleanup(wdir, whiteout);
+ goto out_d_drop;
+}
+
+static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
+{
+ struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
+ struct inode *dir = upperdir->d_inode;
+ struct dentry *upper;
+ struct dentry *opaquedir = NULL;
+ int err;
+
+ /* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */
+ if (is_dir && ovl_dentry_get_redirect(dentry)) {
+ opaquedir = ovl_check_empty_and_clear(dentry);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir))
+ goto out;
+ }
+
+ inode_lock_nested(dir, I_MUTEX_PARENT);
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (IS_ERR(upper))
+ goto out_unlock;
+
+ err = -ESTALE;
+ if ((opaquedir && upper != opaquedir) ||
+ (!opaquedir && !ovl_matches_upper(dentry, upper)))
+ goto out_dput_upper;
+
+ if (is_dir)
+ err = vfs_rmdir(dir, upper);
+ else
+ err = vfs_unlink(dir, upper, NULL);
+ ovl_dentry_version_inc(dentry->d_parent, ovl_type_origin(dentry));
+
+ /*
+ * Keeping this dentry hashed would mean having to release
+ * upperpath/lowerpath, which could only be done if we are the
+ * sole user of this dentry. Too tricky... Just unhash for
+ * now.
+ */
+ if (!err)
+ d_drop(dentry);
+out_dput_upper:
+ dput(upper);
+out_unlock:
+ inode_unlock(dir);
+ dput(opaquedir);
+out:
+ return err;
+}
+
+static int ovl_do_remove(struct dentry *dentry, bool is_dir)
+{
+ int err;
+ bool locked = false;
+ const struct cred *old_cred;
+
+ err = ovl_want_write(dentry);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(dentry->d_parent);
+ if (err)
+ goto out_drop_write;
+
+ err = ovl_nlink_start(dentry, &locked);
+ if (err)
+ goto out_drop_write;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ if (!ovl_lower_positive(dentry))
+ err = ovl_remove_upper(dentry, is_dir);
+ else
+ err = ovl_remove_and_whiteout(dentry, is_dir);
+ revert_creds(old_cred);
+ if (!err) {
+ if (is_dir)
+ clear_nlink(dentry->d_inode);
+ else
+ drop_nlink(dentry->d_inode);
+ }
+ ovl_nlink_end(dentry, locked);
+out_drop_write:
+ ovl_drop_write(dentry);
+out:
+ return err;
+}
+
+static int ovl_unlink(struct inode *dir, struct dentry *dentry)
+{
+ return ovl_do_remove(dentry, false);
+}
+
+static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ return ovl_do_remove(dentry, true);
+}
+
+static bool ovl_type_merge_or_lower(struct dentry *dentry)
+{
+ enum ovl_path_type type = ovl_path_type(dentry);
+
+ return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
+}
+
+static bool ovl_can_move(struct dentry *dentry)
+{
+ return ovl_redirect_dir(dentry->d_sb) ||
+ !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
+}
+
+static char *ovl_get_redirect(struct dentry *dentry, bool samedir)
+{
+ char *buf, *ret;
+ struct dentry *d, *tmp;
+ int buflen = ovl_redirect_max + 1;
+
+ if (samedir) {
+ ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
+ GFP_KERNEL);
+ goto out;
+ }
+
+ buf = ret = kmalloc(buflen, GFP_KERNEL);
+ if (!buf)
+ goto out;
+
+ buflen--;
+ buf[buflen] = '\0';
+ for (d = dget(dentry); !IS_ROOT(d);) {
+ const char *name;
+ int thislen;
+
+ spin_lock(&d->d_lock);
+ name = ovl_dentry_get_redirect(d);
+ if (name) {
+ thislen = strlen(name);
+ } else {
+ name = d->d_name.name;
+ thislen = d->d_name.len;
+ }
+
+ /* If path is too long, fall back to userspace move */
+ if (thislen + (name[0] != '/') > buflen) {
+ ret = ERR_PTR(-EXDEV);
+ spin_unlock(&d->d_lock);
+ goto out_put;
+ }
+
+ buflen -= thislen;
+ memcpy(&buf[buflen], name, thislen);
+ tmp = dget_dlock(d->d_parent);
+ spin_unlock(&d->d_lock);
+
+ dput(d);
+ d = tmp;
+
+ /* Absolute redirect: finished */
+ if (buf[buflen] == '/')
+ break;
+ buflen--;
+ buf[buflen] = '/';
+ }
+ ret = kstrdup(&buf[buflen], GFP_KERNEL);
+out_put:
+ dput(d);
+ kfree(buf);
+out:
+ return ret ? ret : ERR_PTR(-ENOMEM);
+}
+
+static int ovl_set_redirect(struct dentry *dentry, bool samedir)
+{
+ int err;
+ const char *redirect = ovl_dentry_get_redirect(dentry);
+
+ if (redirect && (samedir || redirect[0] == '/'))
+ return 0;
+
+ redirect = ovl_get_redirect(dentry, samedir);
+ if (IS_ERR(redirect))
+ return PTR_ERR(redirect);
+
+ err = ovl_check_setxattr(dentry, ovl_dentry_upper(dentry),
+ OVL_XATTR_REDIRECT,
+ redirect, strlen(redirect), -EXDEV);
+ if (!err) {
+ spin_lock(&dentry->d_lock);
+ ovl_dentry_set_redirect(dentry, redirect);
+ spin_unlock(&dentry->d_lock);
+ } else {
+ kfree(redirect);
+ pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err);
+ /* Fall back to userspace copy-up */
+ err = -EXDEV;
+ }
+ return err;
+}
+
+static int ovl_rename(struct inode *olddir, struct dentry *old,
+ struct inode *newdir, struct dentry *new,
+ unsigned int flags)
+{
+ int err;
+ bool locked = false;
+ struct dentry *old_upperdir;
+ struct dentry *new_upperdir;
+ struct dentry *olddentry;
+ struct dentry *newdentry;
+ struct dentry *trap;
+ bool old_opaque;
+ bool new_opaque;
+ bool cleanup_whiteout = false;
+ bool overwrite = !(flags & RENAME_EXCHANGE);
+ bool is_dir = d_is_dir(old);
+ bool new_is_dir = d_is_dir(new);
+ bool samedir = olddir == newdir;
+ struct dentry *opaquedir = NULL;
+ const struct cred *old_cred = NULL;
+
+ err = -EINVAL;
+ if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
+ goto out;
+
+ flags &= ~RENAME_NOREPLACE;
+
+ /* Don't copy up directory trees */
+ err = -EXDEV;
+ if (!ovl_can_move(old))
+ goto out;
+ if (!overwrite && !ovl_can_move(new))
+ goto out;
+
+ err = ovl_want_write(old);
+ if (err)
+ goto out;
+
+ err = ovl_copy_up(old);
+ if (err)
+ goto out_drop_write;
+
+ err = ovl_copy_up(new->d_parent);
+ if (err)
+ goto out_drop_write;
+ if (!overwrite) {
+ err = ovl_copy_up(new);
+ if (err)
+ goto out_drop_write;
+ } else {
+ err = ovl_nlink_start(new, &locked);
+ if (err)
+ goto out_drop_write;
+ }
+
+ old_cred = ovl_override_creds(old->d_sb);
+
+ if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) {
+ opaquedir = ovl_check_empty_and_clear(new);
+ err = PTR_ERR(opaquedir);
+ if (IS_ERR(opaquedir)) {
+ opaquedir = NULL;
+ goto out_revert_creds;
+ }
+ }
+
+ if (overwrite) {
+ if (ovl_lower_positive(old)) {
+ if (!ovl_dentry_is_whiteout(new)) {
+ /* Whiteout source */
+ flags |= RENAME_WHITEOUT;
+ } else {
+ /* Switch whiteouts */
+ flags |= RENAME_EXCHANGE;
+ }
+ } else if (is_dir && ovl_dentry_is_whiteout(new)) {
+ flags |= RENAME_EXCHANGE;
+ cleanup_whiteout = true;
+ }
+ }
+
+ old_upperdir = ovl_dentry_upper(old->d_parent);
+ new_upperdir = ovl_dentry_upper(new->d_parent);
+
+ if (!samedir) {
+ /*
+ * When moving a merge dir or non-dir with copy up origin into
+ * a new parent, we are marking the new parent dir "impure".
+ * When ovl_iterate() iterates an "impure" upper dir, it will
+ * lookup the origin inodes of the entries to fill d_ino.
+ */
+ if (ovl_type_origin(old)) {
+ err = ovl_set_impure(new->d_parent, new_upperdir);
+ if (err)
+ goto out_revert_creds;
+ }
+ if (!overwrite && ovl_type_origin(new)) {
+ err = ovl_set_impure(old->d_parent, old_upperdir);
+ if (err)
+ goto out_revert_creds;
+ }
+ }
+
+ trap = lock_rename(new_upperdir, old_upperdir);
+
+ olddentry = lookup_one_len(old->d_name.name, old_upperdir,
+ old->d_name.len);
+ err = PTR_ERR(olddentry);
+ if (IS_ERR(olddentry))
+ goto out_unlock;
+
+ err = -ESTALE;
+ if (!ovl_matches_upper(old, olddentry))
+ goto out_dput_old;
+
+ newdentry = lookup_one_len(new->d_name.name, new_upperdir,
+ new->d_name.len);
+ err = PTR_ERR(newdentry);
+ if (IS_ERR(newdentry))
+ goto out_dput_old;
+
+ old_opaque = ovl_dentry_is_opaque(old);
+ new_opaque = ovl_dentry_is_opaque(new);
+
+ err = -ESTALE;
+ if (d_inode(new) && ovl_dentry_upper(new)) {
+ if (opaquedir) {
+ if (newdentry != opaquedir)
+ goto out_dput;
+ } else {
+ if (!ovl_matches_upper(new, newdentry))
+ goto out_dput;
+ }
+ } else {
+ if (!d_is_negative(newdentry) &&
+ (!new_opaque || !ovl_is_whiteout(newdentry)))
+ goto out_dput;
+ }
+
+ if (olddentry == trap)
+ goto out_dput;
+ if (newdentry == trap)
+ goto out_dput;
+
+ if (olddentry->d_inode == newdentry->d_inode)
+ goto out_dput;
+
+ err = 0;
+ if (is_dir) {
+ if (ovl_type_merge_or_lower(old))
+ err = ovl_set_redirect(old, samedir);
+ else if (!old_opaque && ovl_type_merge(new->d_parent))
+ err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
+ if (err)
+ goto out_dput;
+ }
+ if (!overwrite && new_is_dir) {
+ if (ovl_type_merge_or_lower(new))
+ err = ovl_set_redirect(new, samedir);
+ else if (!new_opaque && ovl_type_merge(old->d_parent))
+ err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
+ if (err)
+ goto out_dput;
+ }
+
+ err = ovl_do_rename(old_upperdir->d_inode, olddentry,
+ new_upperdir->d_inode, newdentry, flags);
+ if (err)
+ goto out_dput;
+
+ if (cleanup_whiteout)
+ ovl_cleanup(old_upperdir->d_inode, newdentry);
+
+ if (overwrite && d_inode(new)) {
+ if (new_is_dir)
+ clear_nlink(d_inode(new));
+ else
+ drop_nlink(d_inode(new));
+ }
+
+ ovl_dentry_version_inc(old->d_parent,
+ !overwrite && ovl_type_origin(new));
+ ovl_dentry_version_inc(new->d_parent, ovl_type_origin(old));
+
+out_dput:
+ dput(newdentry);
+out_dput_old:
+ dput(olddentry);
+out_unlock:
+ unlock_rename(new_upperdir, old_upperdir);
+out_revert_creds:
+ revert_creds(old_cred);
+ ovl_nlink_end(new, locked);
+out_drop_write:
+ ovl_drop_write(old);
+out:
+ dput(opaquedir);
+ return err;
+}
+
+const struct inode_operations ovl_dir_inode_operations = {
+ .lookup = ovl_lookup,
+ .mkdir = ovl_mkdir,
+ .symlink = ovl_symlink,
+ .unlink = ovl_unlink,
+ .rmdir = ovl_rmdir,
+ .rename = ovl_rename,
+ .link = ovl_link,
+ .setattr = ovl_setattr,
+ .create = ovl_create,
+ .mknod = ovl_mknod,
+ .permission = ovl_permission,
+ .getattr = ovl_getattr,
+ .listxattr = ovl_listxattr,
+ .get_acl = ovl_get_acl,
+ .update_time = ovl_update_time,
+};