From patchwork Tue Nov 22 02:15:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Rosenberg X-Patchwork-Id: 13051841 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CE44C4332F for ; Tue, 22 Nov 2022 02:20:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232696AbiKVCUo (ORCPT ); Mon, 21 Nov 2022 21:20:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232561AbiKVCTi (ORCPT ); Mon, 21 Nov 2022 21:19:38 -0500 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2BEDE9145 for ; Mon, 21 Nov 2022 18:16:41 -0800 (PST) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-39ce6773614so58076787b3.2 for ; Mon, 21 Nov 2022 18:16:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=xynMcMsTuZqMLXL5ELmNHCW5CNZGRvCuOQzJlNlxPiE=; b=OUOhjEq4CnL9PVEr0QtLZtsjmGIU43rGzRaSI9yqkOCe/Tq6OgBYhpEJftwd6UWyQ/ 5eeE3FmCGczyreI5r/W4v9N5jqJoGlmQM2q02oW82bjyNtSfMiVAKuuRlyzzRCpqIjcK JqE5A8cs7Nov5Mp1Pr5ppPvmjSjUDvqdNwrEJcxCVXa1nPeGGAqVPzHzrRRvLfekRmG7 QN92GztkE/9jyU1ktQ0mdS+rYMrfjbUKE1XfIg7zDourWrv+MzvWMpNiFOUi1VzoyY63 oGRcclGwP2xBOMc//CIF4OX7JWonfe7495+rdT4v40NBqMMb/aLuZjA/x9Bb7/9mHKQn NAIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=xynMcMsTuZqMLXL5ELmNHCW5CNZGRvCuOQzJlNlxPiE=; b=TOl3u2c+uohwS1FSyKqHfrxygLhg7kGE8K7B4VW9mWx2IAnYdmdcpcfX0OGB6KD45D KwnztPWKMx/Tp7ocFF8kypCQIsGiVblKhxnb+LepVw8wmB/uwF8R+5g70BATdvPIemR7 1501okgUtpXe8tbx7r96YqdfqYI+jQGvFinkukdiiAqJqj4sAnAsj/O2pNBGx1nVxNgV KpfZdfXaV22S9HrXGEKBG3MqEkHdcDBcBBn3Sv9PtgX+raYF9yqDYzghFJRIM3/QuNOu nUodapfbi3OYhtsiLtIdDm2uCYra2GtJeiFYGwROSGvcCWmn5Do4CvbLJcfI2at6EjIq YVZA== X-Gm-Message-State: ANoB5pkGQpjX7MVx2benRCGbaeKHfnsgEvBrXZDrmbw69SQZcX/+9c6O 4g4rUzAvxtwjuyzrrQJSOsSJVxtnpTQ= X-Google-Smtp-Source: AA0mqf4LGEir7+sUn3JQztooPiTqpoL0ZtXzAn9x3BZieAdky+AC347ieh3djGRKoZYQgLnIiAdZ6bEKgno= X-Received: from drosen.mtv.corp.google.com ([2620:15c:211:200:8539:aadd:13be:6e82]) (user=drosen job=sendgmr) by 2002:a25:ae12:0:b0:6d0:704:f19f with SMTP id a18-20020a25ae12000000b006d00704f19fmr4415884ybj.191.1669083400889; Mon, 21 Nov 2022 18:16:40 -0800 (PST) Date: Mon, 21 Nov 2022 18:15:35 -0800 In-Reply-To: <20221122021536.1629178-1-drosen@google.com> Mime-Version: 1.0 References: <20221122021536.1629178-1-drosen@google.com> X-Mailer: git-send-email 2.38.1.584.g0f3c55d4c2-goog Message-ID: <20221122021536.1629178-21-drosen@google.com> Subject: [RFC PATCH v2 20/21] fuse-bpf: Add symlink/link support From: Daniel Rosenberg To: Miklos Szeredi Cc: Amir Goldstein , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, kernel-team@android.com, Daniel Rosenberg , Paul Lawrence Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-State: RFC Signed-off-by: Daniel Rosenberg Signed-off-by: Paul Lawrence --- fs/fuse/backing.c | 271 ++++++++++++++++++++++++++++++++++++++++++++++ fs/fuse/dir.c | 11 ++ fs/fuse/fuse_i.h | 20 ++++ 3 files changed, 302 insertions(+) diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c index 05fb88865289..a77414e8f3df 100644 --- a/fs/fuse/backing.c +++ b/fs/fuse/backing.c @@ -2319,6 +2319,104 @@ int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry) dir, entry); } +static int fuse_link_initialize_in(struct fuse_args *fa, struct fuse_link_in *fli, + struct dentry *entry, struct inode *dir, + struct dentry *newent) +{ + struct inode *src_inode = entry->d_inode; + + *fli = (struct fuse_link_in) { + .oldnodeid = get_node_id(src_inode), + }; + + fa->opcode = FUSE_LINK; + fa->in_numargs = 2; + fa->in_args[0].size = sizeof(*fli); + fa->in_args[0].value = fli; + fa->in_args[1].size = newent->d_name.len + 1; + fa->in_args[1].value = (void *) newent->d_name.name; + + return 0; +} + +static int fuse_link_initialize_out(struct fuse_args *fa, struct fuse_link_in *fli, + struct dentry *entry, struct inode *dir, + struct dentry *newent) +{ + return 0; +} + +static int fuse_link_backing(struct fuse_args *fa, int *out, struct dentry *entry, + struct inode *dir, struct dentry *newent) +{ + struct path backing_old_path; + struct path backing_new_path; + struct dentry *backing_dir_dentry; + struct inode *fuse_new_inode = NULL; + struct fuse_inode *fuse_dir_inode = get_fuse_inode(dir); + struct inode *backing_dir_inode = fuse_dir_inode->backing_inode; + + *out = 0; + get_fuse_backing_path(entry, &backing_old_path); + if (!backing_old_path.dentry) + return -EBADF; + + get_fuse_backing_path(newent, &backing_new_path); + if (!backing_new_path.dentry) { + *out = -EBADF; + goto err_dst_path; + } + + backing_dir_dentry = dget_parent(backing_new_path.dentry); + backing_dir_inode = d_inode(backing_dir_dentry); + + inode_lock_nested(backing_dir_inode, I_MUTEX_PARENT); + *out = vfs_link(backing_old_path.dentry, &init_user_ns, + backing_dir_inode, backing_new_path.dentry, NULL); + inode_unlock(backing_dir_inode); + if (*out) + goto out; + + if (d_really_is_negative(backing_new_path.dentry) || + unlikely(d_unhashed(backing_new_path.dentry))) { + *out = -EINVAL; + /** + * TODO: overlayfs responds to this situation with a + * lookupOneLen. Should we do that too? + */ + goto out; + } + + fuse_new_inode = fuse_iget_backing(dir->i_sb, fuse_dir_inode->nodeid, backing_dir_inode); + if (IS_ERR(fuse_new_inode)) { + *out = PTR_ERR(fuse_new_inode); + goto out; + } + d_instantiate(newent, fuse_new_inode); + +out: + dput(backing_dir_dentry); + path_put(&backing_new_path); +err_dst_path: + path_put(&backing_old_path); + return *out; +} + +static int fuse_link_finalize(struct fuse_args *fa, int *out, struct dentry *entry, + struct inode *dir, struct dentry *newent) +{ + return 0; +} + +int fuse_bpf_link(int *out, struct inode *inode, struct dentry *entry, + struct inode *newdir, struct dentry *newent) +{ + return fuse_bpf_backing(inode, struct fuse_link_in, out, + fuse_link_initialize_in, fuse_link_initialize_out, + fuse_link_backing, fuse_link_finalize, entry, + newdir, newent); +} + struct fuse_getattr_io { struct fuse_getattr_in fgi; struct fuse_attr_out fao; @@ -2600,6 +2698,179 @@ int fuse_bpf_statfs(int *out, struct inode *inode, struct dentry *dentry, struct dentry, buf); } +static int fuse_get_link_initialize_in(struct fuse_args *fa, struct fuse_unused_io *unused, + struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + /* + * TODO + * If we want to handle changing these things, we'll need to copy + * the lower fs's data into our own buffer, and provide our own callback + * to free that buffer. + * + * Pre could change the name we're looking at + * postfilter can change the name we return + * + * We ought to only make that buffer if it's been requested, so leaving + * this unimplemented for the moment + */ + *fa = (struct fuse_args) { + .opcode = FUSE_READLINK, + .nodeid = get_node_id(inode), + .in_numargs = 1, + .in_args[0] = (struct fuse_in_arg) { + .size = dentry->d_name.len + 1, + .value = (void *) dentry->d_name.name, + }, + /* + * .out_argvar = 1, + * .out_numargs = 1, + * .out_args[0].size = , + * .out_args[0].value = , + */ + }; + + return 0; +} + +static int fuse_get_link_initialize_out(struct fuse_args *fa, struct fuse_unused_io *unused, + struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + /* + * .out_argvar = 1, + * .out_numargs = 1, + * .out_args[0].size = , + * .out_args[0].value = , + */ + + return 0; +} + +static int fuse_get_link_backing(struct fuse_args *fa, const char **out, + struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + struct path backing_path; + + if (!dentry) { + *out = ERR_PTR(-ECHILD); + return PTR_ERR(*out); + } + + get_fuse_backing_path(dentry, &backing_path); + if (!backing_path.dentry) { + *out = ERR_PTR(-ECHILD); + return PTR_ERR(*out); + } + + /* + * TODO: If we want to do our own thing, copy the data and then call the + * callback + */ + *out = vfs_get_link(backing_path.dentry, callback); + + path_put(&backing_path); + return 0; +} + +static int fuse_get_link_finalize(struct fuse_args *fa, const char **out, + struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + return 0; +} + +int fuse_bpf_get_link(const char **out, struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + return fuse_bpf_backing(inode, struct fuse_unused_io, out, + fuse_get_link_initialize_in, fuse_get_link_initialize_out, + fuse_get_link_backing, + fuse_get_link_finalize, + inode, dentry, callback); +} + +static int fuse_symlink_initialize_in(struct fuse_args *fa, struct fuse_unused_io *unused, + struct inode *dir, struct dentry *entry, const char *link, int len) +{ + *fa = (struct fuse_args) { + .nodeid = get_node_id(dir), + .opcode = FUSE_SYMLINK, + .in_numargs = 2, + .in_args[0] = (struct fuse_in_arg) { + .size = entry->d_name.len + 1, + .value = (void *) entry->d_name.name, + }, + .in_args[1] = (struct fuse_in_arg) { + .size = len, + .value = (void *) link, + }, + }; + + return 0; +} + +static int fuse_symlink_initialize_out(struct fuse_args *fa, struct fuse_unused_io *unused, + struct inode *dir, struct dentry *entry, const char *link, int len) +{ + return 0; +} + +static int fuse_symlink_backing(struct fuse_args *fa, int *out, + struct inode *dir, struct dentry *entry, const char *link, int len) +{ + struct fuse_inode *fuse_inode = get_fuse_inode(dir); + struct inode *backing_inode = fuse_inode->backing_inode; + struct path backing_path; + struct inode *inode = NULL; + + *out = 0; + //TODO Actually deal with changing the backing entry in symlink + get_fuse_backing_path(entry, &backing_path); + if (!backing_path.dentry) + return -EBADF; + + inode_lock_nested(backing_inode, I_MUTEX_PARENT); + *out = vfs_symlink(&init_user_ns, backing_inode, backing_path.dentry, + link); + inode_unlock(backing_inode); + if (*out) + goto out; + if (d_really_is_negative(backing_path.dentry) || + unlikely(d_unhashed(backing_path.dentry))) { + *out = -EINVAL; + /** + * TODO: overlayfs responds to this situation with a + * lookupOneLen. Should we do that too? + */ + goto out; + } + inode = fuse_iget_backing(dir->i_sb, fuse_inode->nodeid, backing_inode); + if (IS_ERR(inode)) { + *out = PTR_ERR(inode); + goto out; + } + d_instantiate(entry, inode); +out: + path_put(&backing_path); + return *out; +} + +static int fuse_symlink_finalize(struct fuse_args *fa, int *out, + struct inode *dir, struct dentry *entry, const char *link, int len) +{ + return 0; +} + +int fuse_bpf_symlink(int *out, struct inode *dir, struct dentry *entry, const char *link, int len) +{ + return fuse_bpf_backing(dir, struct fuse_unused_io, out, + fuse_symlink_initialize_in, fuse_symlink_initialize_out, + fuse_symlink_backing, fuse_symlink_finalize, + dir, entry, link, len); +} + struct fuse_read_io { struct fuse_read_in fri; struct fuse_read_out fro; diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 899de6c84c2e..1f9105edc7e2 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -945,6 +945,10 @@ static int fuse_symlink(struct user_namespace *mnt_userns, struct inode *dir, struct fuse_mount *fm = get_fuse_mount(dir); unsigned len = strlen(link) + 1; FUSE_ARGS(args); + int err; + + if (fuse_bpf_symlink(&err, dir, entry, link, len)) + return err; args.opcode = FUSE_SYMLINK; args.in_numargs = 2; @@ -1151,6 +1155,9 @@ static int fuse_link(struct dentry *entry, struct inode *newdir, struct fuse_mount *fm = get_fuse_mount(inode); FUSE_ARGS(args); + if (fuse_bpf_link(&err, inode, entry, newdir, newent)) + return err; + memset(&inarg, 0, sizeof(inarg)); inarg.oldnodeid = get_node_id(inode); args.opcode = FUSE_LINK; @@ -1543,12 +1550,16 @@ static const char *fuse_get_link(struct dentry *dentry, struct inode *inode, { struct fuse_conn *fc = get_fuse_conn(inode); struct page *page; + const char *out = NULL; int err; err = -EIO; if (fuse_is_bad(inode)) goto out_err; + if (fuse_bpf_get_link(&out, inode, dentry, callback)) + return out; + if (fc->cache_symlinks) return page_get_link(dentry, inode, callback); diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 37b29a3ea330..99c9231ec98b 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -1412,6 +1412,7 @@ int fuse_bpf_rename2(int *out, struct inode *olddir, struct dentry *oldent, int fuse_bpf_rename(int *out, struct inode *olddir, struct dentry *oldent, struct inode *newdir, struct dentry *newent); int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *entry); +int fuse_bpf_link(int *out, struct inode *inode, struct dentry *entry, struct inode *dir, struct dentry *newent); int fuse_bpf_release(int *out, struct inode *inode, struct file *file); int fuse_bpf_releasedir(int *out, struct inode *inode, struct file *file); int fuse_bpf_flush(int *out, struct inode *inode, struct file *file, fl_owner_t id); @@ -1436,6 +1437,9 @@ int fuse_bpf_getattr(int *out, struct inode *inode, const struct dentry *entry, u32 request_mask, unsigned int flags); int fuse_bpf_setattr(int *out, struct inode *inode, struct dentry *dentry, struct iattr *attr, struct file *file); int fuse_bpf_statfs(int *out, struct inode *inode, struct dentry *dentry, struct kstatfs *buf); +int fuse_bpf_get_link(const char **out, struct inode *inode, struct dentry *dentry, + struct delayed_call *callback); +int fuse_bpf_symlink(int *out, struct inode *dir, struct dentry *entry, const char *link, int len); int fuse_bpf_readdir(int *out, struct inode *inode, struct file *file, struct dir_context *ctx); int fuse_bpf_access(int *out, struct inode *inode, int mask); @@ -1485,6 +1489,11 @@ static inline int fuse_bpf_unlink(int *out, struct inode *dir, struct dentry *en return 0; } +static inline int fuse_bpf_link(int *out, struct inode *inode, struct dentry *entry, struct inode *dir, struct dentry *newent) +{ + return 0; +} + static inline int fuse_bpf_release(int *out, struct inode *inode, struct file *file) { return 0; @@ -1581,6 +1590,17 @@ static inline int fuse_bpf_statfs(int *out, struct inode *inode, struct dentry * return 0; } +static inline int fuse_bpf_get_link(const char **out, struct inode *inode, struct dentry *dentry, + struct delayed_call *callback) +{ + return 0; +} + +static inline int fuse_bpf_symlink(int *out, struct inode *dir, struct dentry *entry, const char *link, int len) +{ + return 0; +} + static inline int fuse_bpf_readdir(int *out, struct inode *inode, struct file *file, struct dir_context *ctx) { return 0;