| /* |
| * |
| * 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 ? old_cred : current_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: |
| ovl_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); |
| ovl_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 (WARN_ON(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: |
| ovl_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, |
| }; |