Extract the code that runs under overridden credentials into a separate do_ovl_rename() helper function. Error handling is simplified. The helper returns errors directly instead of using goto labels. Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner --- fs/overlayfs/dir.c | 277 +++++++++++++++++++++++++++-------------------------- 1 file changed, 140 insertions(+), 137 deletions(-) diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c index 052929b9b99d..0812bb4ee4f6 100644 --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -1099,107 +1099,28 @@ struct ovl_renamedata { bool overwrite; }; -static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, - struct dentry *old, struct inode *newdir, - struct dentry *new, unsigned int flags) +static int do_ovl_rename(struct ovl_renamedata *ovlrd, struct list_head *list) { - int err; - struct dentry *old_upperdir; - struct dentry *new_upperdir; - struct dentry *trap, *de; - bool old_opaque; - bool new_opaque; - bool update_nlink = false; + struct dentry *old = ovlrd->old_dentry; + struct dentry *new = ovlrd->new_dentry; + struct ovl_fs *ofs = OVL_FS(old->d_sb); + unsigned int flags = ovlrd->flags; + struct dentry *old_upperdir = ovl_dentry_upper(ovlrd->old_parent); + struct dentry *new_upperdir = ovl_dentry_upper(ovlrd->new_parent); + bool samedir = ovlrd->old_parent == ovlrd->new_parent; bool is_dir = d_is_dir(old); bool new_is_dir = d_is_dir(new); - const struct cred *old_cred = NULL; - struct ovl_fs *ofs = OVL_FS(old->d_sb); - struct ovl_renamedata ovlrd = { - .old_parent = old->d_parent, - .old_dentry = old, - .new_parent = new->d_parent, - .new_dentry = new, - .flags = flags, - .cleanup_whiteout = false, - .overwrite = !(flags & RENAME_EXCHANGE), - }; - LIST_HEAD(list); - bool samedir = ovlrd.old_parent == ovlrd.new_parent; - - err = -EINVAL; - if (ovlrd.flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) - goto out; - - ovlrd.flags &= ~RENAME_NOREPLACE; - - /* Don't copy up directory trees */ - err = -EXDEV; - if (!ovl_can_move(old)) - goto out; - if (!ovlrd.overwrite && !ovl_can_move(new)) - goto out; - - if (ovlrd.overwrite && new_is_dir && !ovl_pure_upper(new)) { - err = ovl_check_empty_dir(new, &list); - if (err) - goto out; - } - - if (ovlrd.overwrite) { - if (ovl_lower_positive(old)) { - if (!ovl_dentry_is_whiteout(new)) { - /* Whiteout source */ - ovlrd.flags |= RENAME_WHITEOUT; - } else { - /* Switch whiteouts */ - ovlrd.flags |= RENAME_EXCHANGE; - } - } else if (is_dir && ovl_dentry_is_whiteout(new)) { - ovlrd.flags |= RENAME_EXCHANGE; - ovlrd.cleanup_whiteout = true; - } - } - - err = ovl_copy_up(old); - if (err) - goto out; - - err = ovl_copy_up(ovlrd.new_parent); - if (err) - goto out; - if (!ovlrd.overwrite) { - err = ovl_copy_up(new); - if (err) - goto out; - } else if (d_inode(new)) { - err = ovl_nlink_start(new); - if (err) - goto out; - - update_nlink = true; - } - - if (!update_nlink) { - /* ovl_nlink_start() took ovl_want_write() */ - err = ovl_want_write(old); - if (err) - goto out; - } - - old_cred = ovl_override_creds(old->d_sb); + struct dentry *trap, *de; + bool old_opaque, new_opaque; + int err; - if (!list_empty(&list)) { - ovlrd.opaquedir = ovl_clear_empty(new, &list); - err = PTR_ERR(ovlrd.opaquedir); - if (IS_ERR(ovlrd.opaquedir)) { - ovlrd.opaquedir = NULL; - goto out_revert_creds; - } + if (!list_empty(list)) { + de = ovl_clear_empty(new, list); + if (IS_ERR(de)) + return PTR_ERR(de); + ovlrd->opaquedir = de; } - old_upperdir = ovl_dentry_upper(ovlrd.old_parent); - new_upperdir = ovl_dentry_upper(ovlrd.new_parent); - if (!samedir) { /* * When moving a merge dir or non-dir with copy up origin into @@ -1208,32 +1129,30 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, * lookup the origin inodes of the entries to fill d_ino. */ if (ovl_type_origin(old)) { - err = ovl_set_impure(ovlrd.new_parent, new_upperdir); + err = ovl_set_impure(ovlrd->new_parent, new_upperdir); if (err) - goto out_revert_creds; + return err; } - if (!ovlrd.overwrite && ovl_type_origin(new)) { - err = ovl_set_impure(ovlrd.old_parent, old_upperdir); + if (!ovlrd->overwrite && ovl_type_origin(new)) { + err = ovl_set_impure(ovlrd->old_parent, old_upperdir); if (err) - goto out_revert_creds; + return err; } } trap = lock_rename(new_upperdir, old_upperdir); - if (IS_ERR(trap)) { - err = PTR_ERR(trap); - goto out_revert_creds; - } + if (IS_ERR(trap)) + return PTR_ERR(trap); de = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir, old->d_name.len); err = PTR_ERR(de); if (IS_ERR(de)) goto out_unlock; - ovlrd.olddentry = de; + ovlrd->olddentry = de; err = -ESTALE; - if (!ovl_matches_upper(old, ovlrd.olddentry)) + if (!ovl_matches_upper(old, ovlrd->olddentry)) goto out_unlock; de = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir, @@ -1241,73 +1160,74 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, err = PTR_ERR(de); if (IS_ERR(de)) goto out_unlock; - ovlrd.newdentry = de; + ovlrd->newdentry = de; 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 (ovlrd.opaquedir) { - if (ovlrd.newdentry != ovlrd.opaquedir) + if (ovlrd->opaquedir) { + if (ovlrd->newdentry != ovlrd->opaquedir) goto out_unlock; } else { - if (!ovl_matches_upper(new, ovlrd.newdentry)) + if (!ovl_matches_upper(new, ovlrd->newdentry)) goto out_unlock; } } else { - if (!d_is_negative(ovlrd.newdentry)) { - if (!new_opaque || !ovl_upper_is_whiteout(ofs, ovlrd.newdentry)) + if (!d_is_negative(ovlrd->newdentry)) { + if (!new_opaque || !ovl_upper_is_whiteout(ofs, ovlrd->newdentry)) goto out_unlock; } else { - if (ovlrd.flags & RENAME_EXCHANGE) + if (flags & RENAME_EXCHANGE) goto out_unlock; } } - if (ovlrd.olddentry == trap) + if (ovlrd->olddentry == trap) goto out_unlock; - if (ovlrd.newdentry == trap) + if (ovlrd->newdentry == trap) goto out_unlock; - if (ovlrd.olddentry->d_inode == ovlrd.newdentry->d_inode) + if (ovlrd->olddentry->d_inode == ovlrd->newdentry->d_inode) goto out_unlock; err = 0; if (ovl_type_merge_or_lower(old)) err = ovl_set_redirect(old, samedir); - else if (is_dir && !old_opaque && ovl_type_merge(ovlrd.new_parent)) - err = ovl_set_opaque_xerr(old, ovlrd.olddentry, -EXDEV); + else if (is_dir && !old_opaque && ovl_type_merge(ovlrd->new_parent)) + err = ovl_set_opaque_xerr(old, ovlrd->olddentry, -EXDEV); if (err) goto out_unlock; - if (!ovlrd.overwrite && ovl_type_merge_or_lower(new)) + if (!ovlrd->overwrite && ovl_type_merge_or_lower(new)) err = ovl_set_redirect(new, samedir); - else if (!ovlrd.overwrite && new_is_dir && !new_opaque && - ovl_type_merge(ovlrd.old_parent)) - err = ovl_set_opaque_xerr(new, ovlrd.newdentry, -EXDEV); + else if (!ovlrd->overwrite && new_is_dir && !new_opaque && + ovl_type_merge(ovlrd->old_parent)) + err = ovl_set_opaque_xerr(new, ovlrd->newdentry, -EXDEV); if (err) goto out_unlock; - err = ovl_do_rename(ofs, old_upperdir, ovlrd.olddentry, - new_upperdir, ovlrd.newdentry, flags); + err = ovl_do_rename(ofs, old_upperdir, ovlrd->olddentry, + new_upperdir, ovlrd->newdentry, flags); +out_unlock: unlock_rename(new_upperdir, old_upperdir); if (err) - goto out_revert_creds; + return err; - if (ovlrd.cleanup_whiteout) - ovl_cleanup(ofs, old_upperdir, ovlrd.newdentry); + if (ovlrd->cleanup_whiteout) + ovl_cleanup(ofs, old_upperdir, ovlrd->newdentry); - if (ovlrd.overwrite && d_inode(new)) { + if (ovlrd->overwrite && d_inode(new)) { if (new_is_dir) clear_nlink(d_inode(new)); else ovl_drop_nlink(new); } - ovl_dir_modified(ovlrd.old_parent, ovl_type_origin(old) || - (!ovlrd.overwrite && ovl_type_origin(new))); - ovl_dir_modified(ovlrd.new_parent, ovl_type_origin(old) || + ovl_dir_modified(ovlrd->old_parent, ovl_type_origin(old) || + (!ovlrd->overwrite && ovl_type_origin(new))); + ovl_dir_modified(ovlrd->new_parent, ovl_type_origin(old) || (d_inode(new) && ovl_type_origin(new))); /* copy ctime: */ @@ -1315,22 +1235,105 @@ static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, if (d_inode(new) && ovl_dentry_upper(new)) ovl_copyattr(d_inode(new)); -out_revert_creds: + return err; +} + +static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir, + struct dentry *old, struct inode *newdir, + struct dentry *new, unsigned int flags) +{ + int err; + bool update_nlink = false; + bool is_dir = d_is_dir(old); + bool new_is_dir = d_is_dir(new); + const struct cred *old_cred = NULL; + struct ovl_renamedata ovlrd = { + .old_parent = old->d_parent, + .old_dentry = old, + .new_parent = new->d_parent, + .new_dentry = new, + .flags = flags, + .cleanup_whiteout = false, + .overwrite = !(flags & RENAME_EXCHANGE), + }; + LIST_HEAD(list); + + err = -EINVAL; + if (ovlrd.flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) + goto out; + + ovlrd.flags &= ~RENAME_NOREPLACE; + + /* Don't copy up directory trees */ + err = -EXDEV; + if (!ovl_can_move(old)) + goto out; + if (!ovlrd.overwrite && !ovl_can_move(new)) + goto out; + + if (ovlrd.overwrite && new_is_dir && !ovl_pure_upper(new)) { + err = ovl_check_empty_dir(new, &list); + if (err) + goto out; + } + + if (ovlrd.overwrite) { + if (ovl_lower_positive(old)) { + if (!ovl_dentry_is_whiteout(new)) { + /* Whiteout source */ + ovlrd.flags |= RENAME_WHITEOUT; + } else { + /* Switch whiteouts */ + ovlrd.flags |= RENAME_EXCHANGE; + } + } else if (is_dir && ovl_dentry_is_whiteout(new)) { + ovlrd.flags |= RENAME_EXCHANGE; + ovlrd.cleanup_whiteout = true; + } + } + + err = ovl_copy_up(old); + if (err) + goto out; + + err = ovl_copy_up(new->d_parent); + if (err) + goto out; + if (!ovlrd.overwrite) { + err = ovl_copy_up(new); + if (err) + goto out; + } else if (d_inode(new)) { + err = ovl_nlink_start(new); + if (err) + goto out; + + update_nlink = true; + } + + if (!update_nlink) { + /* ovl_nlink_start() took ovl_want_write() */ + err = ovl_want_write(old); + if (err) + goto out; + } + + old_cred = ovl_override_creds(old->d_sb); + + err = do_ovl_rename(&ovlrd, &list); + ovl_revert_creds(old_cred); if (update_nlink) ovl_nlink_end(new); else ovl_drop_write(old); -out: + dput(ovlrd.newdentry); dput(ovlrd.olddentry); dput(ovlrd.opaquedir); +out: ovl_cache_free(&list); return err; - -out_unlock: - unlock_rename(new_upperdir, old_upperdir); - goto out_revert_creds; } static int ovl_create_tmpfile(struct file *file, struct dentry *dentry, -- 2.47.3