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/ext4/ext4_jbd2.c | 425 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 425 insertions(+) create mode 100644 fs/ext4/ext4_jbd2.c (limited to 'fs/ext4/ext4_jbd2.c') diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c new file mode 100644 index 000000000..02b066299 --- /dev/null +++ b/fs/ext4/ext4_jbd2.c @@ -0,0 +1,425 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Interface between ext4 and JBD + */ + +#include "ext4_jbd2.h" + +#include + +int ext4_inode_journal_mode(struct inode *inode) +{ + if (EXT4_JOURNAL(inode) == NULL) + return EXT4_INODE_WRITEBACK_DATA_MODE; /* writeback */ + /* We do not support data journalling with delayed allocation */ + if (!S_ISREG(inode->i_mode) || + ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE) || + test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA || + (ext4_test_inode_flag(inode, EXT4_INODE_JOURNAL_DATA) && + !test_opt(inode->i_sb, DELALLOC))) { + /* We do not support data journalling for encrypted data */ + if (S_ISREG(inode->i_mode) && IS_ENCRYPTED(inode)) + return EXT4_INODE_ORDERED_DATA_MODE; /* ordered */ + return EXT4_INODE_JOURNAL_DATA_MODE; /* journal data */ + } + if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA) + return EXT4_INODE_ORDERED_DATA_MODE; /* ordered */ + if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_WRITEBACK_DATA) + return EXT4_INODE_WRITEBACK_DATA_MODE; /* writeback */ + BUG(); +} + +/* Just increment the non-pointer handle value */ +static handle_t *ext4_get_nojournal(void) +{ + handle_t *handle = current->journal_info; + unsigned long ref_cnt = (unsigned long)handle; + + BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT); + + ref_cnt++; + handle = (handle_t *)ref_cnt; + + current->journal_info = handle; + return handle; +} + + +/* Decrement the non-pointer handle value */ +static void ext4_put_nojournal(handle_t *handle) +{ + unsigned long ref_cnt = (unsigned long)handle; + + BUG_ON(ref_cnt == 0); + + ref_cnt--; + handle = (handle_t *)ref_cnt; + + current->journal_info = handle; +} + +/* + * Wrappers for jbd2_journal_start/end. + */ +static int ext4_journal_check_start(struct super_block *sb) +{ + int ret; + journal_t *journal; + + might_sleep(); + + ret = ext4_emergency_state(sb); + if (unlikely(ret)) + return ret; + + if (WARN_ON_ONCE(sb_rdonly(sb))) + return -EROFS; + + WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); + journal = EXT4_SB(sb)->s_journal; + /* + * Special case here: if the journal has aborted behind our + * backs (eg. EIO in the commit thread), then we still need to + * take the FS itself readonly cleanly. + */ + if (journal && is_journal_aborted(journal)) { + ext4_abort(sb, -journal->j_errno, "Detected aborted journal"); + return -EROFS; + } + return 0; +} + +handle_t *__ext4_journal_start_sb(struct inode *inode, + struct super_block *sb, unsigned int line, + int type, int blocks, int rsv_blocks, + int revoke_creds) +{ + journal_t *journal; + int err; + if (inode) + trace_ext4_journal_start_inode(inode, blocks, rsv_blocks, + revoke_creds, type, + _RET_IP_); + else + trace_ext4_journal_start_sb(sb, blocks, rsv_blocks, + revoke_creds, type, + _RET_IP_); + err = ext4_journal_check_start(sb); + if (err < 0) + return ERR_PTR(err); + + journal = EXT4_SB(sb)->s_journal; + if (!journal || (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)) + return ext4_get_nojournal(); + return jbd2__journal_start(journal, blocks, rsv_blocks, revoke_creds, + GFP_NOFS, type, line); +} + +int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) +{ + struct super_block *sb; + int err; + int rc; + + if (!ext4_handle_valid(handle)) { + ext4_put_nojournal(handle); + return 0; + } + + err = handle->h_err; + if (!handle->h_transaction) { + rc = jbd2_journal_stop(handle); + return err ? err : rc; + } + + sb = handle->h_transaction->t_journal->j_private; + rc = jbd2_journal_stop(handle); + + if (!err) + err = rc; + if (err) + __ext4_std_error(sb, where, line, err); + return err; +} + +handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line, + int type) +{ + struct super_block *sb; + int err; + + if (!ext4_handle_valid(handle)) + return ext4_get_nojournal(); + + sb = handle->h_journal->j_private; + trace_ext4_journal_start_reserved(sb, + jbd2_handle_buffer_credits(handle), _RET_IP_); + err = ext4_journal_check_start(sb); + if (err < 0) { + jbd2_journal_free_reserved(handle); + return ERR_PTR(err); + } + + err = jbd2_journal_start_reserved(handle, type, line); + if (err < 0) + return ERR_PTR(err); + return handle; +} + +int __ext4_journal_ensure_credits(handle_t *handle, int check_cred, + int extend_cred, int revoke_cred) +{ + if (!ext4_handle_valid(handle)) + return 0; + if (is_handle_aborted(handle)) + return -EROFS; + if (jbd2_handle_buffer_credits(handle) >= check_cred && + handle->h_revoke_credits >= revoke_cred) + return 0; + extend_cred = max(0, extend_cred - jbd2_handle_buffer_credits(handle)); + revoke_cred = max(0, revoke_cred - handle->h_revoke_credits); + return ext4_journal_extend(handle, extend_cred, revoke_cred); +} + +static void ext4_journal_abort_handle(const char *caller, unsigned int line, + const char *err_fn, + struct buffer_head *bh, + handle_t *handle, int err) +{ + char nbuf[16]; + const char *errstr = ext4_decode_error(NULL, err, nbuf); + + BUG_ON(!ext4_handle_valid(handle)); + + if (bh) + BUFFER_TRACE(bh, "abort"); + + if (!handle->h_err) + handle->h_err = err; + + if (is_handle_aborted(handle)) + return; + + printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n", + caller, line, errstr, err_fn); + + jbd2_journal_abort_handle(handle); +} + +static void ext4_check_bdev_write_error(struct super_block *sb) +{ + struct address_space *mapping = sb->s_bdev->bd_mapping; + struct ext4_sb_info *sbi = EXT4_SB(sb); + int err; + + /* + * If the block device has write error flag, it may have failed to + * async write out metadata buffers in the background. In this case, + * we could read old data from disk and write it out again, which + * may lead to on-disk filesystem inconsistency. + */ + if (errseq_check(&mapping->wb_err, READ_ONCE(sbi->s_bdev_wb_err))) { + spin_lock(&sbi->s_bdev_wb_lock); + err = errseq_check_and_advance(&mapping->wb_err, &sbi->s_bdev_wb_err); + spin_unlock(&sbi->s_bdev_wb_lock); + if (err) + ext4_error_err(sb, -err, + "Error while async write back metadata"); + } +} + +int __ext4_journal_get_write_access(const char *where, unsigned int line, + handle_t *handle, struct super_block *sb, + struct buffer_head *bh, + enum ext4_journal_trigger_type trigger_type) +{ + int err; + + might_sleep(); + + if (ext4_handle_valid(handle)) { + err = jbd2_journal_get_write_access(handle, bh); + if (err) { + ext4_journal_abort_handle(where, line, __func__, bh, + handle, err); + return err; + } + } else + ext4_check_bdev_write_error(sb); + if (trigger_type == EXT4_JTR_NONE || + !ext4_has_feature_metadata_csum(sb)) + return 0; + BUG_ON(trigger_type >= EXT4_JOURNAL_TRIGGER_COUNT); + jbd2_journal_set_triggers(bh, + &EXT4_SB(sb)->s_journal_triggers[trigger_type].tr_triggers); + return 0; +} + +/* + * The ext4 forget function must perform a revoke if we are freeing data + * which has been journaled. Metadata (eg. indirect blocks) must be + * revoked in all cases. + * + * "bh" may be NULL: a metadata block may have been freed from memory + * but there may still be a record of it in the journal, and that record + * still needs to be revoked. + */ +int __ext4_forget(const char *where, unsigned int line, handle_t *handle, + int is_metadata, struct inode *inode, + struct buffer_head *bh, ext4_fsblk_t blocknr) +{ + int err; + + might_sleep(); + + trace_ext4_forget(inode, is_metadata, blocknr); + BUFFER_TRACE(bh, "enter"); + + ext4_debug("forgetting bh %p: is_metadata=%d, mode %o, data mode %x\n", + bh, is_metadata, inode->i_mode, + test_opt(inode->i_sb, DATA_FLAGS)); + + /* + * In the no journal case, we should wait for the ongoing buffer + * to complete and do a forget. + */ + if (!ext4_handle_valid(handle)) { + if (bh) { + clear_buffer_dirty(bh); + wait_on_buffer(bh); + __bforget(bh); + } + return 0; + } + + /* Never use the revoke function if we are doing full data + * journaling: there is no need to, and a V1 superblock won't + * support it. Otherwise, only skip the revoke on un-journaled + * data blocks. */ + + if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA || + (!is_metadata && !ext4_should_journal_data(inode))) { + if (bh) { + BUFFER_TRACE(bh, "call jbd2_journal_forget"); + err = jbd2_journal_forget(handle, bh); + if (err) + ext4_journal_abort_handle(where, line, __func__, + bh, handle, err); + return err; + } + return 0; + } + + /* + * data!=journal && (is_metadata || should_journal_data(inode)) + */ + BUFFER_TRACE(bh, "call jbd2_journal_revoke"); + err = jbd2_journal_revoke(handle, blocknr, bh); + if (err) { + ext4_journal_abort_handle(where, line, __func__, + bh, handle, err); + __ext4_error(inode->i_sb, where, line, true, -err, 0, + "error %d when attempting revoke", err); + } + BUFFER_TRACE(bh, "exit"); + return err; +} + +int __ext4_journal_get_create_access(const char *where, unsigned int line, + handle_t *handle, struct super_block *sb, + struct buffer_head *bh, + enum ext4_journal_trigger_type trigger_type) +{ + int err; + + if (!ext4_handle_valid(handle)) + return 0; + + err = jbd2_journal_get_create_access(handle, bh); + if (err) { + ext4_journal_abort_handle(where, line, __func__, bh, handle, + err); + return err; + } + if (trigger_type == EXT4_JTR_NONE || + !ext4_has_feature_metadata_csum(sb)) + return 0; + BUG_ON(trigger_type >= EXT4_JOURNAL_TRIGGER_COUNT); + jbd2_journal_set_triggers(bh, + &EXT4_SB(sb)->s_journal_triggers[trigger_type].tr_triggers); + return 0; +} + +static void ext4_inode_attach_mmb(struct inode *inode) +{ + struct mapping_metadata_bhs *mmb; + + /* + * It's difficult to handle failure when marking buffer dirty without + * leaving filesystem corrupted + */ + mmb = kmalloc_obj(*mmb, GFP_NOFS | __GFP_NOFAIL | __GFP_ACCOUNT); + mmb_init(mmb, &inode->i_data); + /* Someone swapped another mmb before us? */ + if (cmpxchg(&EXT4_I(inode)->i_metadata_bhs, NULL, mmb)) + kfree(mmb); +} + +int __ext4_handle_dirty_metadata(const char *where, unsigned int line, + handle_t *handle, struct inode *inode, + struct buffer_head *bh) +{ + int err = 0; + + might_sleep(); + + set_buffer_meta(bh); + set_buffer_prio(bh); + set_buffer_uptodate(bh); + if (ext4_handle_valid(handle)) { + err = jbd2_journal_dirty_metadata(handle, bh); + /* Errors can only happen due to aborted journal or a nasty bug */ + if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) { + ext4_journal_abort_handle(where, line, __func__, bh, + handle, err); + if (inode == NULL) { + pr_err("EXT4: jbd2_journal_dirty_metadata " + "failed: handle type %u started at " + "line %u, credits %u/%u, errcode %d", + handle->h_type, + handle->h_line_no, + handle->h_requested_credits, + jbd2_handle_buffer_credits(handle), err); + return err; + } + ext4_error_inode(inode, where, line, + bh->b_blocknr, + "journal_dirty_metadata failed: " + "handle type %u started at line %u, " + "credits %u/%u, errcode %d", + handle->h_type, + handle->h_line_no, + handle->h_requested_credits, + jbd2_handle_buffer_credits(handle), + err); + } + } else { + if (inode) { + if (!ext4_i_metadata_bhs(inode)) + ext4_inode_attach_mmb(inode); + mmb_mark_buffer_dirty(bh, ext4_i_metadata_bhs(inode)); + } else { + mark_buffer_dirty(bh); + } + if (inode && inode_needs_sync(inode)) { + sync_dirty_buffer(bh); + if (buffer_req(bh) && !buffer_uptodate(bh)) { + ext4_error_inode_err(inode, where, line, + bh->b_blocknr, EIO, + "IO error syncing itable block"); + err = -EIO; + } + } + } + return err; +} -- cgit v1.3.1