From patchwork Wed Oct 23 13:37:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13847117 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 9A1462914 for ; Wed, 23 Oct 2024 13:38:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729690683; cv=none; b=MnXYgpQjnSo0UcIAetj5uiaR0j/t/9bpDFey4wS6bv80wjB87Uwd/aIVEb104Me6hzyDFPHzLQFehFP469udIhlBojVg/vdY89J4r9D4Z5bzBUptMXtACouykU59uSIRHGE0PdsDr2ydqxcwAaNCMMUfPNR5khFDIAnhCXyvki4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729690683; c=relaxed/simple; bh=FU8F+XEww1F9LMGaK9nnb2ZdnN4V5D3lIch14enJvhM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=H+AvbjM0h7EbQymLuuNpnelb7VbdMM+3f83581Ltz7ZwKWN0pmV6TchcAWNlNgHcD7UIuf4ZL7FqZTrEBsV7P/U/NNpSu5msg2B5NGihZBJ/4378jQLsaco4mNzxSPCzNCYxJ6ClMtI+oDI2+s8agpURDOqS5lg/o7OldsaY8ts= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=nxpirRuQ; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nxpirRuQ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=7rVeCOZnY6uXUIGfClkZFlmtdkD4SlX+rqbCKt+kFYE=; b=nxpirRuQqokN2i+lbNO5Su0LQK oJcL6N5AQOdKJ/DkPN8h5OdC79FrcGJEXaEyeRxfyggf0LYMJGSxuLl4pYxdsIOsdY2pn4MTKiTvl 2eD22I34lerAR0VN7XSQqbxJyG4DZI0K01AesXnSiBrvc241QGDWlX5kheRLWnEJfglS42BHnit/o cxR7e3iJ8Ft3/vuiAFeRc8Vm8eHVMBiMvq503g12RayPeyw1gVF8FWoDmcAjbYeNhZEoadH4CTQgw UFEMlTJNMUYGWYIm3yta5CthdCuWiKW52D5q98OreC11otFtuRERMkE5eIweU7PaoFGDIcUP1ZesU /NpaVF6A==; Received: from 2a02-8389-2341-5b80-8c6c-e123-fc47-94a5.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:8c6c:e123:fc47:94a5] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1t3bYm-0000000EZWB-2hn4; Wed, 23 Oct 2024 13:38:01 +0000 From: Christoph Hellwig To: Carlos Maiolino Cc: "Darrick J. Wong" , linux-xfs@vger.kernel.org, syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com Subject: [PATCH 1/2] xfs: fix finding a last resort AG in xfs_filestream_pick_ag Date: Wed, 23 Oct 2024 15:37:22 +0200 Message-ID: <20241023133755.524345-2-hch@lst.de> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241023133755.524345-1-hch@lst.de> References: <20241023133755.524345-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html When the main loop in xfs_filestream_pick_ag fails to find a suitable AG it tries to just pick the online AG. But the loop for that uses args->pag as loop iterator while the later code expects pag to be set. Fix this by reusing the max_pag case for this last resort, and also add a check for impossible case of no AG just to make sure that the uninitialized pag doesn't even escape in theory. Reported-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com Signed-off-by: Christoph Hellwig Tested-by: syzbot+4125a3c514e3436a02e6@syzkaller.appspotmail.com Reviewed-by: Darrick J. Wong --- fs/xfs/xfs_filestream.c | 23 ++++++++++++----------- fs/xfs/xfs_trace.h | 15 +++++---------- 2 files changed, 17 insertions(+), 21 deletions(-) diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c index e3aaa0555597..88bd23ce74cd 100644 --- a/fs/xfs/xfs_filestream.c +++ b/fs/xfs/xfs_filestream.c @@ -64,7 +64,7 @@ xfs_filestream_pick_ag( struct xfs_perag *pag; struct xfs_perag *max_pag = NULL; xfs_extlen_t minlen = *longest; - xfs_extlen_t free = 0, minfree, maxfree = 0; + xfs_extlen_t minfree, maxfree = 0; xfs_agnumber_t agno; bool first_pass = true; int err; @@ -107,7 +107,6 @@ xfs_filestream_pick_ag( !(flags & XFS_PICK_USERDATA) || (flags & XFS_PICK_LOWSPACE))) { /* Break out, retaining the reference on the AG. */ - free = pag->pagf_freeblks; break; } } @@ -150,23 +149,25 @@ xfs_filestream_pick_ag( * grab. */ if (!max_pag) { - for_each_perag_wrap(args->mp, 0, start_agno, args->pag) + for_each_perag_wrap(args->mp, 0, start_agno, pag) { + max_pag = pag; break; - atomic_inc(&args->pag->pagf_fstrms); - *longest = 0; - } else { - pag = max_pag; - free = maxfree; - atomic_inc(&pag->pagf_fstrms); + } + + /* Bail if there are no AGs at all to select from. */ + if (!max_pag) + return -ENOSPC; } + + pag = max_pag; + atomic_inc(&pag->pagf_fstrms); } else if (max_pag) { xfs_perag_rele(max_pag); } - trace_xfs_filestream_pick(pag, pino, free); + trace_xfs_filestream_pick(pag, pino); args->pag = pag; return 0; - } static struct xfs_inode * diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h index ee9f0b1f548d..fcb2bad4f76e 100644 --- a/fs/xfs/xfs_trace.h +++ b/fs/xfs/xfs_trace.h @@ -691,8 +691,8 @@ DEFINE_FILESTREAM_EVENT(xfs_filestream_lookup); DEFINE_FILESTREAM_EVENT(xfs_filestream_scan); TRACE_EVENT(xfs_filestream_pick, - TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino, xfs_extlen_t free), - TP_ARGS(pag, ino, free), + TP_PROTO(struct xfs_perag *pag, xfs_ino_t ino), + TP_ARGS(pag, ino), TP_STRUCT__entry( __field(dev_t, dev) __field(xfs_ino_t, ino) @@ -703,14 +703,9 @@ TRACE_EVENT(xfs_filestream_pick, TP_fast_assign( __entry->dev = pag->pag_mount->m_super->s_dev; __entry->ino = ino; - if (pag) { - __entry->agno = pag->pag_agno; - __entry->streams = atomic_read(&pag->pagf_fstrms); - } else { - __entry->agno = NULLAGNUMBER; - __entry->streams = 0; - } - __entry->free = free; + __entry->agno = pag->pag_agno; + __entry->streams = atomic_read(&pag->pagf_fstrms); + __entry->free = pag->pagf_freeblks; ), TP_printk("dev %d:%d ino 0x%llx agno 0x%x streams %d free %d", MAJOR(__entry->dev), MINOR(__entry->dev),