From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- fs/afs/dir_silly.c | 289 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 289 insertions(+) create mode 100644 fs/afs/dir_silly.c (limited to 'fs/afs/dir_silly.c') diff --git a/fs/afs/dir_silly.c b/fs/afs/dir_silly.c new file mode 100644 index 000000000..982bb6ec1 --- /dev/null +++ b/fs/afs/dir_silly.c @@ -0,0 +1,289 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* AFS silly rename handling + * + * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * - Derived from NFS's sillyrename. + */ + +#include +#include +#include +#include +#include "internal.h" + +static void afs_silly_rename_success(struct afs_operation *op) +{ + _enter("op=%08x", op->debug_id); + + afs_check_dir_conflict(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[0]); +} + +static void afs_silly_rename_edit_dir(struct afs_operation *op) +{ + struct afs_vnode_param *dvp = &op->file[0]; + struct afs_vnode *dvnode = dvp->vnode; + struct afs_vnode *vnode = AFS_FS_I(d_inode(op->dentry)); + struct dentry *old = op->dentry; + struct dentry *new = op->dentry_2; + + spin_lock(&old->d_lock); + old->d_flags |= DCACHE_NFSFS_RENAMED; + spin_unlock(&old->d_lock); + if (dvnode->silly_key != op->key) { + key_put(dvnode->silly_key); + dvnode->silly_key = key_get(op->key); + } + + down_write(&dvnode->validate_lock); + if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) && + dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) { + afs_edit_dir_remove(dvnode, &old->d_name, + afs_edit_dir_for_silly_0); + afs_edit_dir_add(dvnode, &new->d_name, + &vnode->fid, afs_edit_dir_for_silly_1); + } + up_write(&dvnode->validate_lock); +} + +static const struct afs_operation_ops afs_silly_rename_operation = { + .issue_afs_rpc = afs_fs_rename, + .issue_yfs_rpc = yfs_fs_rename, + .success = afs_silly_rename_success, + .edit_dir = afs_silly_rename_edit_dir, +}; + +/* + * Actually perform the silly rename step. + */ +static int afs_do_silly_rename(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *old, struct dentry *new, + struct key *key) +{ + struct afs_operation *op; + + _enter("%pd,%pd", old, new); + + op = afs_alloc_operation(key, dvnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + op->more_files = kvzalloc_objs(struct afs_vnode_param, 2); + if (!op->more_files) { + afs_put_operation(op); + return -ENOMEM; + } + + afs_op_set_vnode(op, 0, dvnode); + afs_op_set_vnode(op, 1, dvnode); + op->file[0].dv_delta = 1; + op->file[1].dv_delta = 1; + op->file[0].modification = true; + op->file[1].modification = true; + op->file[0].update_ctime = true; + op->file[1].update_ctime = true; + op->more_files[0].vnode = AFS_FS_I(d_inode(old)); + op->more_files[0].speculative = true; + op->more_files[1].vnode = AFS_FS_I(d_inode(new)); + op->more_files[1].speculative = true; + op->nr_files = 4; + + op->dentry = old; + op->dentry_2 = new; + op->ops = &afs_silly_rename_operation; + + trace_afs_silly_rename(vnode, false); + return afs_do_sync_operation(op); +} + +/* + * Perform silly-rename of a dentry. + * + * AFS is stateless and the server doesn't know when the client is holding a + * file open. To prevent application problems when a file is unlinked while + * it's still open, the client performs a "silly-rename". That is, it renames + * the file to a hidden file in the same directory, and only performs the + * unlink once the last reference to it is put. + * + * The final cleanup is done during dentry_iput. + */ +int afs_sillyrename(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *dentry, struct key *key) +{ + static unsigned int sillycounter; + struct dentry *sdentry = NULL; + unsigned char silly[16]; + int ret = -EBUSY; + + _enter(""); + + /* We don't allow a dentry to be silly-renamed twice. */ + if (dentry->d_flags & DCACHE_NFSFS_RENAMED) + return -EBUSY; + + sdentry = NULL; + do { + dput(sdentry); + sillycounter++; + + /* Create a silly name. Note that the ".__afs" prefix is + * understood by the salvager and must not be changed. + */ + scnprintf(silly, sizeof(silly), ".__afs%04X", sillycounter); + sdentry = lookup_noperm(&QSTR(silly), dentry->d_parent); + + /* N.B. Better to return EBUSY here ... it could be dangerous + * to delete the file while it's in use. + */ + if (IS_ERR(sdentry)) + goto out; + } while (!d_is_negative(sdentry)); + + ihold(&vnode->netfs.inode); + + ret = afs_do_silly_rename(dvnode, vnode, dentry, sdentry, key); + switch (ret) { + case 0: + /* The rename succeeded. */ + set_bit(AFS_VNODE_SILLY_DELETED, &vnode->flags); + d_move(dentry, sdentry); + break; + case -ERESTARTSYS: + /* The result of the rename is unknown. Play it safe by forcing + * a new lookup. + */ + d_drop(dentry); + d_drop(sdentry); + } + + iput(&vnode->netfs.inode); + dput(sdentry); +out: + _leave(" = %d", ret); + return ret; +} + +static void afs_silly_unlink_success(struct afs_operation *op) +{ + _enter("op=%08x", op->debug_id); + afs_check_dir_conflict(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[0]); + afs_vnode_commit_status(op, &op->file[1]); + afs_update_dentry_version(op, &op->file[0], op->dentry); +} + +static void afs_silly_unlink_edit_dir(struct afs_operation *op) +{ + struct afs_vnode_param *dvp = &op->file[0]; + struct afs_vnode *dvnode = dvp->vnode; + + _enter("op=%08x", op->debug_id); + down_write(&dvnode->validate_lock); + if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags) && + dvnode->status.data_version == dvp->dv_before + dvp->dv_delta) + afs_edit_dir_remove(dvnode, &op->dentry->d_name, + afs_edit_dir_for_unlink); + up_write(&dvnode->validate_lock); +} + +static const struct afs_operation_ops afs_silly_unlink_operation = { + .issue_afs_rpc = afs_fs_remove_file, + .issue_yfs_rpc = yfs_fs_remove_file, + .success = afs_silly_unlink_success, + .aborted = afs_check_for_remote_deletion, + .edit_dir = afs_silly_unlink_edit_dir, +}; + +/* + * Tell the server to remove a sillyrename file. + */ +static int afs_do_silly_unlink(struct afs_vnode *dvnode, struct afs_vnode *vnode, + struct dentry *dentry, struct key *key) +{ + struct afs_operation *op; + + _enter(""); + + op = afs_alloc_operation(NULL, dvnode->volume); + if (IS_ERR(op)) + return PTR_ERR(op); + + afs_op_set_vnode(op, 0, dvnode); + afs_op_set_vnode(op, 1, vnode); + op->file[0].dv_delta = 1; + op->file[0].modification = true; + op->file[0].update_ctime = true; + op->file[1].op_unlinked = true; + op->file[1].update_ctime = true; + + op->dentry = dentry; + op->ops = &afs_silly_unlink_operation; + + trace_afs_silly_rename(vnode, true); + afs_begin_vnode_operation(op); + afs_wait_for_operation(op); + + /* If there was a conflict with a third party, check the status of the + * unlinked vnode. + */ + if (op->cumul_error.error == 0 && (op->flags & AFS_OPERATION_DIR_CONFLICT)) { + op->file[1].update_ctime = false; + op->fetch_status.which = 1; + op->ops = &afs_fetch_status_operation; + afs_begin_vnode_operation(op); + afs_wait_for_operation(op); + } + + return afs_put_operation(op); +} + +/* + * Remove sillyrename file on iput. + */ +int afs_silly_iput(struct dentry *dentry, struct inode *inode) +{ + struct afs_vnode *dvnode = AFS_FS_I(d_inode(dentry->d_parent)); + struct afs_vnode *vnode = AFS_FS_I(inode); + struct dentry *alias; + int ret; + + _enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode); + + down_read(&dvnode->rmdir_lock); + + alias = d_alloc_parallel(dentry->d_parent, &dentry->d_name); + if (IS_ERR(alias)) { + up_read(&dvnode->rmdir_lock); + return 0; + } + + if (!d_in_lookup(alias)) { + /* We raced with lookup... See if we need to transfer the + * sillyrename information to the aliased dentry. + */ + ret = 0; + spin_lock(&alias->d_lock); + if (d_really_is_positive(alias) && + !(alias->d_flags & DCACHE_NFSFS_RENAMED)) { + alias->d_flags |= DCACHE_NFSFS_RENAMED; + ret = 1; + } + spin_unlock(&alias->d_lock); + up_read(&dvnode->rmdir_lock); + dput(alias); + return ret; + } + + /* Stop lock-release from complaining. */ + spin_lock(&vnode->lock); + vnode->lock_state = AFS_VNODE_LOCK_DELETED; + trace_afs_flock_ev(vnode, NULL, afs_flock_silly_delete, 0); + spin_unlock(&vnode->lock); + + afs_do_silly_unlink(dvnode, vnode, dentry, dvnode->silly_key); + up_read(&dvnode->rmdir_lock); + d_lookup_done(alias); + dput(alias); + return 1; +} -- cgit v1.3.1