From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+3nO5v2YWtrp3at0CxdBx4shygl9aVwf8pqr24avSFbUVnwrX0JLWt+vkal0j7JQ6d2reL ARC-Seal: i=1; a=rsa-sha256; t=1523399245; cv=none; d=google.com; s=arc-20160816; b=r1mINuNkXLWBPrLakgpjqR2SZBsAKYIMsbrXjsIK8g/uk3gfiSOwB7mRwJbaqryK4n DoTuZX7SFK95S7z5ByZHUcWnI3VdZYA9lpjM92wUjTaTWzVbS6MbbnPR3lGEdZuwx7/L +v6U8kpuCvfmVQ9E08zeb2nt65aOPMPqO+q7FCCd6XyC4AcZyMls7xq02ybDClKdSxx3 c+UHaDQ2ued+xJox+Vsr0hB0ika3wvnULF0ykc5EHx1l9rfLzqu0dpKVPLtiCdAGJvgc Nxqu3OxfmRdypIUGaNJZC8IE/d8ADA7zwQj3F1cvFXiVP5N8u7IfD29VX0Ci6GHzR4KK +87g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=mn0KZ/l8MEsNtIR6yNaW7ulCulvRTdZrDtPBTmwDX2Y=; b=H7a+TZWfYUk4NV9wEif9NxUge43agl1+iwPnRXfo/p2CDCDIMuccmnQPtfAZ7lXCJ8 6J2Za1qc2PVAceFjFANiOwnajWkbY8oSuJJzPbTOkisDQy5zk8V7SIEo8W8Lr/yT3oiF ZqedAXLCpuKnmgshz4HgTlItltQfhKaa1qO1Yjz/ASxgXewSyronSA5y3e7qyK4Yjpg1 HQqVRHIWvyUPALZ7TlDJ1NWSgQHoUS9kVAgIULzLVcPOZkeWlmUMa+IssixkxaFhMRzh INmEszCs9wscewQqDVDvJKjsYfAoozvfMXYjnemKLjSagjxZs1HS9rJfvPbSQfyKnSH1 KwRw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 4.15 031/168] f2fs: fix lock dependency in between dio_rwsem & i_mmap_sem Date: Wed, 11 Apr 2018 00:22:53 +0200 Message-Id: <20180410212801.523191136@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180410212800.144079021@linuxfoundation.org> References: <20180410212800.144079021@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1597399887053156628?= X-GMAIL-MSGID: =?utf-8?q?1597399887053156628?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Yu [ Upstream commit 21020812c9e1ab593367fad9ce579f842a0b406d ] test/generic/208 reports a potential deadlock as below: Chain exists of: &mm->mmap_sem --> &fi->i_mmap_sem --> &fi->dio_rwsem[WRITE] Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&fi->dio_rwsem[WRITE]); lock(&fi->i_mmap_sem); lock(&fi->dio_rwsem[WRITE]); lock(&mm->mmap_sem); This patch changes the lock dependency as below in fallocate() to fix this issue: - dio_rwsem - i_mmap_sem Fixes: bb06664a534b ("f2fs: avoid race in between GC and block exchange") Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/file.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1186,14 +1186,14 @@ static int f2fs_collapse_range(struct in pg_start = offset >> PAGE_SHIFT; pg_end = (offset + len) >> PAGE_SHIFT; + /* avoid gc operation during block exchange */ + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + down_write(&F2FS_I(inode)->i_mmap_sem); /* write out all dirty pages from offset */ ret = filemap_write_and_wait_range(inode->i_mapping, offset, LLONG_MAX); if (ret) - goto out; - - /* avoid gc operation during block exchange */ - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + goto out_unlock; truncate_pagecache(inode, offset); @@ -1212,9 +1212,8 @@ static int f2fs_collapse_range(struct in if (!ret) f2fs_i_size_write(inode, new_size); out_unlock: - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); -out: up_write(&F2FS_I(inode)->i_mmap_sem); + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); return ret; } @@ -1385,6 +1384,9 @@ static int f2fs_insert_range(struct inod f2fs_balance_fs(sbi, true); + /* avoid gc operation during block exchange */ + down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); + down_write(&F2FS_I(inode)->i_mmap_sem); ret = truncate_blocks(inode, i_size_read(inode), true); if (ret) @@ -1395,9 +1397,6 @@ static int f2fs_insert_range(struct inod if (ret) goto out; - /* avoid gc operation during block exchange */ - down_write(&F2FS_I(inode)->dio_rwsem[WRITE]); - truncate_pagecache(inode, offset); pg_start = offset >> PAGE_SHIFT; @@ -1425,10 +1424,9 @@ static int f2fs_insert_range(struct inod if (!ret) f2fs_i_size_write(inode, new_size); - - up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); out: up_write(&F2FS_I(inode)->i_mmap_sem); + up_write(&F2FS_I(inode)->dio_rwsem[WRITE]); return ret; }