| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * |
| * Copyright (C) 2011 Novell Inc. |
| */ |
| |
| #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(redirect_max, |
| "Maximum length of absolute redirect xattr value"); |
| |
| static int ovl_set_redirect(struct dentry *dentry, bool samedir); |
| |
| 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; |
| } |
| |
| static 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) |
| { |
| 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; |
| } |
| |
| /* Caller must hold i_mutex on both workdir and dir */ |
| int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir, |
| struct dentry *dentry) |
| { |
| struct inode *wdir = workdir->d_inode; |
| struct dentry *whiteout; |
| int err; |
| int flags = 0; |
| |
| whiteout = ovl_whiteout(workdir); |
| err = PTR_ERR(whiteout); |
| if (IS_ERR(whiteout)) |
| return err; |
| |
| if (d_is_dir(dentry)) |
| flags = RENAME_EXCHANGE; |
| |
| err = ovl_do_rename(wdir, whiteout, dir, dentry, flags); |
| if (err) |
| goto kill_whiteout; |
| if (flags) |
| ovl_cleanup(wdir, dentry); |
| |
| out: |
| dput(whiteout); |
| return err; |
| |
| kill_whiteout: |
| ovl_cleanup(wdir, whiteout); |
| goto out; |
| } |
| |
| int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode) |
| { |
| int err; |
| struct dentry *d, *dentry = *newdentry; |
| |
| err = ovl_do_mkdir(dir, dentry, mode); |
| if (err) |
| return err; |
| |
| if (likely(!d_unhashed(dentry))) |
| return 0; |
| |
| /* |
| * vfs_mkdir() may succeed and leave the dentry passed |
| * to it unhashed and negative. If that happens, try to |
| * lookup a new hashed and positive dentry. |
| */ |
| d = lookup_one_len(dentry->d_name.name, dentry->d_parent, |
| dentry->d_name.len); |
| if (IS_ERR(d)) { |
| pr_warn("overlayfs: failed lookup after mkdir (%pd2, err=%i).\n", |
| dentry, err); |
| return PTR_ERR(d); |
| } |
| dput(dentry); |
| *newdentry = d; |
| |
| return 0; |
| } |
| |
| struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, |
| struct ovl_cattr *attr) |
| { |
| int err; |
| |
| if (IS_ERR(newdentry)) |
| return newdentry; |
| |
| err = -ESTALE; |
| if (newdentry->d_inode) |
| goto out; |
| |
| if (attr->hardlink) { |
| err = ovl_do_link(attr->hardlink, dir, newdentry); |
| } else { |
| switch (attr->mode & S_IFMT) { |
| case S_IFREG: |
| err = ovl_do_create(dir, newdentry, attr->mode); |
| break; |
| |
| case S_IFDIR: |
| /* mkdir is special... */ |
| err = ovl_mkdir_real(dir, &newdentry, attr->mode); |
| break; |
| |
| case S_IFCHR: |
| case S_IFBLK: |
| case S_IFIFO: |
| case S_IFSOCK: |
| err = ovl_do_mknod(dir, newdentry, attr->mode, |
| attr->rdev); |
| break; |
| |
| case S_IFLNK: |
| err = ovl_do_symlink(dir, newdentry, attr->link); |
| 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 = -EIO; |
| } |
| out: |
| if (err) { |
| dput(newdentry); |
| return ERR_PTR(err); |
| } |
| return newdentry; |
| } |
| |
| struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr) |
| { |
| return ovl_create_real(d_inode(workdir), ovl_lookup_temp(workdir), |
| attr); |
| } |
| |
| 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. |
| * If @hardlink is false, then @inode is a pre-allocated inode, we may or |
| * may not use to instantiate the new dentry. |
| */ |
| static int ovl_instantiate(struct dentry *dentry, struct inode *inode, |
| struct dentry *newdentry, bool hardlink) |
| { |
| struct ovl_inode_params oip = { |
| .upperdentry = newdentry, |
| .newinode = inode, |
| }; |
| |
| ovl_dir_modified(dentry->d_parent, false); |
| ovl_dentry_set_upper_alias(dentry); |
| if (!hardlink) { |
| /* |
| * ovl_obtain_alias() can be called after ovl_create_real() |
| * and before we get here, so we may get an inode from cache |
| * with the same real upperdentry that is not the inode we |
| * pre-allocated. In this case we will use the cached inode |
| * to instantiate the new dentry. |
| * |
| * XXX: if we ever use ovl_obtain_alias() to decode directory |
| * file handles, need to use ovl_get_inode_locked() and |
| * d_instantiate_new() here to prevent from creating two |
| * hashed directory inode aliases. |
| */ |
| inode = ovl_get_inode(dentry->d_sb, &oip); |
| if (IS_ERR(inode)) |
| return PTR_ERR(inode); |
| } else { |
| WARN_ON(ovl_inode_real(inode) != d_inode(newdentry)); |
| dput(newdentry); |
| inc_nlink(inode); |
| } |
| |
| d_instantiate(dentry, inode); |
| if (inode != oip.newinode) { |
| pr_warn_ratelimited("overlayfs: newly created inode found in cache (%pd2)\n", |
| dentry); |
| } |
| |
| /* Force lookup of new upper hardlink to find its lower */ |
| if (hardlink) |
| d_drop(dentry); |
| |
| return 0; |
| } |
| |
| 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 ovl_cattr *attr) |
| { |
| struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
| struct inode *udir = upperdir->d_inode; |
| struct dentry *newdentry; |
| int err; |
| |
| if (!attr->hardlink && !IS_POSIXACL(udir)) |
| attr->mode &= ~current_umask(); |
| |
| inode_lock_nested(udir, I_MUTEX_PARENT); |
| newdentry = ovl_create_real(udir, |
| lookup_one_len(dentry->d_name.name, |
| upperdir, |
| dentry->d_name.len), |
| attr); |
| err = PTR_ERR(newdentry); |
| if (IS_ERR(newdentry)) |
| goto out_unlock; |
| |
| 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); |
| } |
| |
| err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink); |
| if (err) |
| goto out_cleanup; |
| out_unlock: |
| inode_unlock(udir); |
| return err; |
| |
| out_cleanup: |
| ovl_cleanup(udir, newdentry); |
| dput(newdentry); |
| goto out_unlock; |
| } |
| |
| 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_create_temp(workdir, OVL_CATTR(stat.mode)); |
| err = PTR_ERR(opaquedir); |
| if (IS_ERR(opaquedir)) |
| goto out_unlock; |
| |
| 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); |
| dput(opaquedir); |
| out_unlock: |
| unlock_rename(workdir, upperdir); |
| out: |
| return ERR_PTR(err); |
| } |
| |
| 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_xattr_size(acl->a_count); |
| buffer = kmalloc(size, GFP_KERNEL); |
| if (!buffer) |
| return -ENOMEM; |
| |
| err = posix_acl_to_xattr(&init_user_ns, acl, buffer, 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 ovl_cattr *cattr) |
| { |
| 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; |
| bool hardlink = !!cattr->hardlink; |
| |
| 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; |
| |
| 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 (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper))) |
| goto out_dput; |
| |
| newdentry = ovl_create_temp(workdir, cattr); |
| err = PTR_ERR(newdentry); |
| if (IS_ERR(newdentry)) |
| goto out_dput; |
| |
| /* |
| * 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; |
| } |
| err = ovl_instantiate(dentry, inode, newdentry, hardlink); |
| if (err) { |
| ovl_cleanup(udir, newdentry); |
| dput(newdentry); |
| } |
| out_dput: |
| dput(upper); |
| 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); |
| dput(newdentry); |
| goto out_dput; |
| } |
| |
| static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
| struct ovl_cattr *attr, bool origin) |
| { |
| int err; |
| const struct cred *old_cred, *hold_cred = NULL; |
| 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; |
| } |
| |
| if (!attr->hardlink) { |
| err = -ENOMEM; |
| override_cred = prepare_creds(); |
| if (!override_cred) |
| goto out_revert_creds; |
| /* |
| * In the creation cases(create, mkdir, mknod, symlink), |
| * ovl should transfer current's fs{u,g}id to underlying |
| * fs. Because underlying fs want to initialize its new |
| * inode owner using current's fs{u,g}id. And in this |
| * case, the @inode is a new inode that is initialized |
| * in inode_init_owner() to current's fs{u,g}id. So use |
| * the inode's i_{u,g}id to override the cred's fs{u,g}id. |
| * |
| * But in the other hardlink case, ovl_link() does not |
| * create a new inode, so just use the ovl mounter's |
| * fs{u,g}id. |
| */ |
| override_cred->fsuid = inode->i_uid; |
| override_cred->fsgid = inode->i_gid; |
| err = security_dentry_create_files_as(dentry, |
| attr->mode, &dentry->d_name, |
| old_cred ? old_cred : current_cred(), |
| override_cred); |
| if (err) { |
| put_cred(override_cred); |
| goto out_revert_creds; |
| } |
| hold_cred = override_creds(override_cred); |
| put_cred(override_cred); |
| } |
| |
| if (!ovl_dentry_is_whiteout(dentry)) |
| err = ovl_create_upper(dentry, inode, attr); |
| else |
| err = ovl_create_over_whiteout(dentry, inode, attr); |
| |
| out_revert_creds: |
| ovl_revert_creds(dentry->d_sb, old_cred ?: hold_cred); |
| if (old_cred && hold_cred) |
| put_cred(hold_cred); |
| return err; |
| } |
| |
| static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, |
| const char *link) |
| { |
| int err; |
| struct inode *inode; |
| struct ovl_cattr attr = { |
| .rdev = rdev, |
| .link = link, |
| }; |
| |
| err = ovl_want_write(dentry); |
| if (err) |
| goto out; |
| |
| /* Preallocate inode to be used by ovl_get_inode() */ |
| err = -ENOMEM; |
| inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
| if (!inode) |
| goto out_drop_write; |
| |
| spin_lock(&inode->i_lock); |
| inode->i_state |= I_CREATING; |
| spin_unlock(&inode->i_lock); |
| |
| inode_init_owner(inode, dentry->d_parent->d_inode, mode); |
| attr.mode = inode->i_mode; |
| |
| err = ovl_create_or_link(dentry, inode, &attr, false); |
| /* Did we end up using the preallocated inode? */ |
| if (inode != d_inode(dentry)) |
| 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_set_link_redirect(struct dentry *dentry) |
| { |
| const struct cred *old_cred; |
| int err; |
| |
| old_cred = ovl_override_creds(dentry->d_sb); |
| err = ovl_set_redirect(dentry, false); |
| ovl_revert_creds(dentry->d_sb, old_cred); |
| |
| return err; |
| } |
| |
| static int ovl_link(struct dentry *old, struct inode *newdir, |
| struct dentry *new) |
| { |
| int err; |
| 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; |
| |
| if (ovl_is_metacopy_dentry(old)) { |
| err = ovl_set_link_redirect(old); |
| if (err) |
| goto out_drop_write; |
| } |
| |
| err = ovl_nlink_start(old); |
| if (err) |
| goto out_drop_write; |
| |
| inode = d_inode(old); |
| ihold(inode); |
| |
| err = ovl_create_or_link(new, inode, |
| &(struct ovl_cattr) {.hardlink = ovl_dentry_upper(old)}, |
| ovl_type_origin(old)); |
| if (err) |
| iput(inode); |
| |
| ovl_nlink_end(old); |
| 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, |
| struct list_head *list) |
| { |
| struct dentry *workdir = ovl_workdir(dentry); |
| struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
| struct dentry *upper; |
| struct dentry *opaquedir = NULL; |
| int err; |
| |
| if (WARN_ON(!workdir)) |
| return -EROFS; |
| |
| if (!list_empty(list)) { |
| opaquedir = ovl_clear_empty(dentry, list); |
| 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; |
| } |
| |
| err = ovl_cleanup_and_whiteout(workdir, d_inode(upperdir), upper); |
| if (err) |
| goto out_d_drop; |
| |
| ovl_dir_modified(dentry->d_parent, true); |
| out_d_drop: |
| d_drop(dentry); |
| out_dput_upper: |
| dput(upper); |
| out_unlock: |
| unlock_rename(workdir, upperdir); |
| out_dput: |
| dput(opaquedir); |
| out: |
| return err; |
| } |
| |
| static int ovl_remove_upper(struct dentry *dentry, bool is_dir, |
| struct list_head *list) |
| { |
| struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); |
| struct inode *dir = upperdir->d_inode; |
| struct dentry *upper; |
| struct dentry *opaquedir = NULL; |
| int err; |
| |
| if (!list_empty(list)) { |
| opaquedir = ovl_clear_empty(dentry, list); |
| 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_dir_modified(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 bool ovl_pure_upper(struct dentry *dentry) |
| { |
| return !ovl_dentry_lower(dentry) && |
| !ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry)); |
| } |
| |
| static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
| { |
| int err; |
| const struct cred *old_cred; |
| struct dentry *upperdentry; |
| bool lower_positive = ovl_lower_positive(dentry); |
| LIST_HEAD(list); |
| |
| /* No need to clean pure upper removed by vfs_rmdir() */ |
| if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) { |
| err = ovl_check_empty_dir(dentry, &list); |
| if (err) |
| goto out; |
| } |
| |
| 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); |
| if (err) |
| goto out_drop_write; |
| |
| old_cred = ovl_override_creds(dentry->d_sb); |
| if (!lower_positive) |
| err = ovl_remove_upper(dentry, is_dir, &list); |
| else |
| err = ovl_remove_and_whiteout(dentry, &list); |
| ovl_revert_creds(dentry->d_sb, old_cred); |
| if (!err) { |
| if (is_dir) |
| clear_nlink(dentry->d_inode); |
| else |
| drop_nlink(dentry->d_inode); |
| } |
| ovl_nlink_end(dentry); |
| |
| /* |
| * Copy ctime |
| * |
| * Note: we fail to update ctime if there was no copy-up, only a |
| * whiteout |
| */ |
| upperdentry = ovl_dentry_upper(dentry); |
| if (upperdentry) |
| ovl_copyattr(d_inode(upperdentry), d_inode(dentry)); |
| |
| out_drop_write: |
| ovl_drop_write(dentry); |
| out: |
| ovl_cache_free(&list); |
| 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 abs_redirect) |
| { |
| char *buf, *ret; |
| struct dentry *d, *tmp; |
| int buflen = ovl_redirect_max + 1; |
| |
| if (!abs_redirect) { |
| 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); |
| spin_unlock(&d->d_lock); |
| tmp = dget_parent(d); |
| |
| 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 bool ovl_need_absolute_redirect(struct dentry *dentry, bool samedir) |
| { |
| struct dentry *lowerdentry; |
| |
| if (!samedir) |
| return true; |
| |
| if (d_is_dir(dentry)) |
| return false; |
| |
| /* |
| * For non-dir hardlinked files, we need absolute redirects |
| * in general as two upper hardlinks could be in different |
| * dirs. We could put a relative redirect now and convert |
| * it to absolute redirect later. But when nlink > 1 and |
| * indexing is on, that means relative redirect needs to be |
| * converted to absolute during copy up of another lower |
| * hardllink as well. |
| * |
| * So without optimizing too much, just check if lower is |
| * a hard link or not. If lower is hard link, put absolute |
| * redirect. |
| */ |
| lowerdentry = ovl_dentry_lower(dentry); |
| return (d_inode(lowerdentry)->i_nlink > 1); |
| } |
| |
| static int ovl_set_redirect(struct dentry *dentry, bool samedir) |
| { |
| int err; |
| const char *redirect = ovl_dentry_get_redirect(dentry); |
| bool absolute_redirect = ovl_need_absolute_redirect(dentry, samedir); |
| |
| if (redirect && (!absolute_redirect || redirect[0] == '/')) |
| return 0; |
| |
| redirect = ovl_get_redirect(dentry, absolute_redirect); |
| 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("overlayfs: 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; |
| 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 update_nlink = 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; |
| LIST_HEAD(list); |
| |
| 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; |
| |
| if (overwrite && new_is_dir && !ovl_pure_upper(new)) { |
| err = ovl_check_empty_dir(new, &list); |
| if (err) |
| goto out; |
| } |
| |
| 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; |
| } |
| } |
| |
| 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 if (d_inode(new)) { |
| err = ovl_nlink_start(new); |
| if (err) |
| goto out_drop_write; |
| |
| update_nlink = true; |
| } |
| |
| old_cred = ovl_override_creds(old->d_sb); |
| |
| if (!list_empty(&list)) { |
| opaquedir = ovl_clear_empty(new, &list); |
| err = PTR_ERR(opaquedir); |
| if (IS_ERR(opaquedir)) { |
| opaquedir = NULL; |
| goto out_revert_creds; |
| } |
| } |
| |
| 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)) { |
| if (!new_opaque || !ovl_is_whiteout(newdentry)) |
| goto out_dput; |
| } else { |
| if (flags & RENAME_EXCHANGE) |
| 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 (ovl_type_merge_or_lower(old)) |
| err = ovl_set_redirect(old, samedir); |
| else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent)) |
| err = ovl_set_opaque_xerr(old, olddentry, -EXDEV); |
| if (err) |
| goto out_dput; |
| |
| if (!overwrite && ovl_type_merge_or_lower(new)) |
| err = ovl_set_redirect(new, samedir); |
| else if (!overwrite && new_is_dir && !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_dir_modified(old->d_parent, ovl_type_origin(old) || |
| (!overwrite && ovl_type_origin(new))); |
| ovl_dir_modified(new->d_parent, ovl_type_origin(old) || |
| (d_inode(new) && ovl_type_origin(new))); |
| |
| /* copy ctime: */ |
| ovl_copyattr(d_inode(olddentry), d_inode(old)); |
| if (d_inode(new) && ovl_dentry_upper(new)) |
| ovl_copyattr(d_inode(newdentry), d_inode(new)); |
| |
| out_dput: |
| dput(newdentry); |
| out_dput_old: |
| dput(olddentry); |
| out_unlock: |
| unlock_rename(new_upperdir, old_upperdir); |
| out_revert_creds: |
| ovl_revert_creds(old->d_sb, old_cred); |
| if (update_nlink) |
| ovl_nlink_end(new); |
| out_drop_write: |
| ovl_drop_write(old); |
| out: |
| dput(opaquedir); |
| ovl_cache_free(&list); |
| 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, |
| }; |