From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA8ED21373 for ; Mon, 29 Jul 2024 11:19:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722251993; cv=none; b=enTZf87iGLqPdH3Bd94mPIIeVNc3xTMkjraIeIc1Q6YmJmeczh25xcJnzRLfsCagIz0BHF8rl7W0Ex4+n5uurdSYNWRDaDgwpJzHOpbcW85qwdJ0dwDAXf0KjqFEDz7xAQIYfSmNzMgTOmsTGdorhpBemu5QHdMu0VQSmxjTjUE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722251993; c=relaxed/simple; bh=jumy7BsmHglYXB7SUWQn7cvbtp2aFWbszqj6qkqRTrQ=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=GX/6OPOpFh/6g81+VYvjDgfCXukbjjnOLUPdDMbN3jQQU3jXefCBzSD2U8tjDlW1QB+Ak32otN+mnM44SbEC/0FQ2TzdnYdw2MT6YTmkEOH2/sBxDhlFMiQYVbnKmZHJpCP5/k5nIH7LzovKJXlOZmDdvT6mmAG0BT0lO+4INhM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=r4Fa3Gxp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="r4Fa3Gxp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF1B8C32786; Mon, 29 Jul 2024 11:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1722251993; bh=jumy7BsmHglYXB7SUWQn7cvbtp2aFWbszqj6qkqRTrQ=; h=Subject:To:Cc:From:Date:From; b=r4Fa3GxpkjZkg/3zv4LwS9bTbgcQ8bYKIBtG6hPkBMQtrv559W+DUKigih6wGDqR3 P3170OZ/eIJzX0o69fIznhqdgf37+1gfJRKGOmQtZI8WK8y6TckAzl6M34VEVUV9VV J82U/e6hWeULPZp1Bf23/0HWq/yQOsnsxedQE2GE= Subject: FAILED: patch "[PATCH] jbd2: avoid infinite transaction commit loop" failed to apply to 6.1-stable tree To: jack@suse.cz,alex.coffin@maticrobots.com,tytso@mit.edu,yi.zhang@huawei.com Cc: From: Date: Mon, 29 Jul 2024 13:19:50 +0200 Message-ID: <2024072949-unframed-extradite-14cf@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 27ba5b67312a944576addc4df44ac3b709aabede # git commit -s git send-email --to '' --in-reply-to '2024072949-unframed-extradite-14cf@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 27ba5b67312a ("jbd2: avoid infinite transaction commit loop") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 27ba5b67312a944576addc4df44ac3b709aabede Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 24 Jun 2024 19:01:19 +0200 Subject: [PATCH] jbd2: avoid infinite transaction commit loop Commit 9f356e5a4f12 ("jbd2: Account descriptor blocks into t_outstanding_credits") started to account descriptor blocks into transactions outstanding credits. However it didn't appropriately decrease the maximum amount of credits available to userspace. Thus if the filesystem requests a transaction smaller than j_max_transaction_buffers but large enough that when descriptor blocks are added the size exceeds j_max_transaction_buffers, we confuse add_transaction_credits() into thinking previous handles have grown the transaction too much and enter infinite journal commit loop in start_this_handle() -> add_transaction_credits() trying to create transaction with enough credits available. Fix the problem by properly accounting for transaction space reserved for descriptor blocks when verifying requested transaction handle size. CC: stable@vger.kernel.org Fixes: 9f356e5a4f12 ("jbd2: Account descriptor blocks into t_outstanding_credits") Reported-by: Alexander Coffin Link: https://lore.kernel.org/all/CA+hUFcuGs04JHZ_WzA1zGN57+ehL2qmHOt5a7RMpo+rv6Vyxtw@mail.gmail.com Signed-off-by: Jan Kara Reviewed-by: Zhang Yi Link: https://patch.msgid.link/20240624170127.3253-3-jack@suse.cz Signed-off-by: Theodore Ts'o diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index a095f1a3114b..66513c18ca29 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -191,6 +191,13 @@ static void sub_reserved_credits(journal_t *journal, int blocks) wake_up(&journal->j_wait_reserved); } +/* Maximum number of blocks for user transaction payload */ +static int jbd2_max_user_trans_buffers(journal_t *journal) +{ + return journal->j_max_transaction_buffers - + journal->j_transaction_overhead_buffers; +} + /* * Wait until we can add credits for handle to the running transaction. Called * with j_state_lock held for reading. Returns 0 if handle joined the running @@ -240,12 +247,12 @@ __must_hold(&journal->j_state_lock) * big to fit this handle? Wait until reserved credits are freed. */ if (atomic_read(&journal->j_reserved_credits) + total > - journal->j_max_transaction_buffers) { + jbd2_max_user_trans_buffers(journal)) { read_unlock(&journal->j_state_lock); jbd2_might_wait_for_commit(journal); wait_event(journal->j_wait_reserved, atomic_read(&journal->j_reserved_credits) + total <= - journal->j_max_transaction_buffers); + jbd2_max_user_trans_buffers(journal)); __acquire(&journal->j_state_lock); /* fake out sparse */ return 1; } @@ -285,14 +292,14 @@ __must_hold(&journal->j_state_lock) needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits); /* We allow at most half of a transaction to be reserved */ - if (needed > journal->j_max_transaction_buffers / 2) { + if (needed > jbd2_max_user_trans_buffers(journal) / 2) { sub_reserved_credits(journal, rsv_blocks); atomic_sub(total, &t->t_outstanding_credits); read_unlock(&journal->j_state_lock); jbd2_might_wait_for_commit(journal); wait_event(journal->j_wait_reserved, atomic_read(&journal->j_reserved_credits) + rsv_blocks - <= journal->j_max_transaction_buffers / 2); + <= jbd2_max_user_trans_buffers(journal) / 2); __acquire(&journal->j_state_lock); /* fake out sparse */ return 1; } @@ -322,12 +329,12 @@ static int start_this_handle(journal_t *journal, handle_t *handle, * size and limit the number of total credits to not exceed maximum * transaction size per operation. */ - if ((rsv_blocks > journal->j_max_transaction_buffers / 2) || - (rsv_blocks + blocks > journal->j_max_transaction_buffers)) { + if (rsv_blocks > jbd2_max_user_trans_buffers(journal) / 2 || + rsv_blocks + blocks > jbd2_max_user_trans_buffers(journal)) { printk(KERN_ERR "JBD2: %s wants too many credits " "credits:%d rsv_credits:%d max:%d\n", current->comm, blocks, rsv_blocks, - journal->j_max_transaction_buffers); + jbd2_max_user_trans_buffers(journal)); WARN_ON(1); return -ENOSPC; }