{"id":2190724,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2190724/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260130031232.60780-3-me@linux.beauty/","project":{"id":8,"url":"http://patchwork.ozlabs.org/api/1.2/projects/8/?format=json","name":"Linux ext4 filesystem development","link_name":"linux-ext4","list_id":"linux-ext4.vger.kernel.org","list_email":"linux-ext4@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260130031232.60780-3-me@linux.beauty>","list_archive_url":null,"date":"2026-01-30T03:12:31","name":"[2/3] ext4: use READ_ONCE for lockless jinode reads","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"433be12c70858d2228b845b7ff704a2a1a9586a7","submitter":{"id":84264,"url":"http://patchwork.ozlabs.org/api/1.2/people/84264/?format=json","name":"Li Chen","email":"me@linux.beauty"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-ext4/patch/20260130031232.60780-3-me@linux.beauty/mbox/","series":[{"id":490324,"url":"http://patchwork.ozlabs.org/api/1.2/series/490324/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ext4/list/?series=490324","date":"2026-01-30T03:12:31","name":"jbd2/ext4/ocfs2: READ_ONCE for lockless jinode reads","version":1,"mbox":"http://patchwork.ozlabs.org/series/490324/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2190724/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2190724/checks/","tags":{},"related":[],"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-ext4@vger.kernel.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","patchwork-incoming@ozlabs.org"],"Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=linux.beauty 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i=me@linux.beauty;\n\th=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:References:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To;\n\tbh=avd/AUZNm7D9+j9YRkdHx4VzxdkkFbvm2wfnuocDPVo=;\n\tb=RC0Gvuh4MNWJZfwXsVBH5PbnA51XJddqMxkpo1mLYHfHRsbOTNmOnoFjkJ65AkIT\n\tsHsYaaCOe3tF+qlaZgDLq4vVk6x1b9CTD9UWno5GJ3qKNf4tmkuEago/cj8BmSOgFiV\n\t7Fn2GjQh8BX5yXOlUGJ8CBCI157pQloE3z8qP3Kg=","From":"Li Chen ","To":"\"Theodore Ts'o\" ,\n\tAndreas Dilger ,\n\tlinux-ext4@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org","Cc":"Jan Kara ,\n\tLi Chen ","Subject":"[PATCH 2/3] ext4: use READ_ONCE for lockless jinode reads","Date":"Fri, 30 Jan 2026 11:12:31 +0800","Message-ID":"<20260130031232.60780-3-me@linux.beauty>","X-Mailer":"git-send-email 2.52.0","In-Reply-To":"<20260130031232.60780-1-me@linux.beauty>","References":"<20260130031232.60780-1-me@linux.beauty>","Precedence":"bulk","X-Mailing-List":"linux-ext4@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-ZohoMailClient":"External","X-Spam-Status":"No, score=-1.2 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_MISSING,\n\tHEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,\n\tSPF_PASS autolearn=disabled version=4.0.1","X-Spam-Checker-Version":"SpamAssassin 4.0.1 (2024-03-25) on gandalf.ozlabs.org"},"content":"ext4 journal commit callbacks access jbd2_inode fields such as\ni_transaction and i_dirty_start/end without holding journal->j_list_lock.\n\nUse READ_ONCE() for these reads to correct the concurrency assumptions.\n\nSuggested-by: Jan Kara \nSigned-off-by: Li Chen \n---\n fs/ext4/inode.c | 6 ++++--\n fs/ext4/super.c | 13 ++++++++-----\n 2 files changed, 12 insertions(+), 7 deletions(-)","diff":"diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\nindex d99296d7315f..2d451388e080 100644\n--- a/fs/ext4/inode.c\n+++ b/fs/ext4/inode.c\n@@ -3033,11 +3033,13 @@ static int ext4_writepages(struct address_space *mapping,\n \n int ext4_normal_submit_inode_data_buffers(struct jbd2_inode *jinode)\n {\n+\tloff_t dirty_start = READ_ONCE(jinode->i_dirty_start);\n+\tloff_t dirty_end = READ_ONCE(jinode->i_dirty_end);\n \tstruct writeback_control wbc = {\n \t\t.sync_mode = WB_SYNC_ALL,\n \t\t.nr_to_write = LONG_MAX,\n-\t\t.range_start = jinode->i_dirty_start,\n-\t\t.range_end = jinode->i_dirty_end,\n+\t\t.range_start = dirty_start,\n+\t\t.range_end = dirty_end,\n \t};\n \tstruct mpage_da_data mpd = {\n \t\t.inode = jinode->i_vfs_inode,\ndiff --git a/fs/ext4/super.c b/fs/ext4/super.c\nindex 5cf6c2b54bbb..acb2bc016fd4 100644\n--- a/fs/ext4/super.c\n+++ b/fs/ext4/super.c\n@@ -521,6 +521,7 @@ static bool ext4_journalled_writepage_needs_redirty(struct jbd2_inode *jinode,\n {\n \tstruct buffer_head *bh, *head;\n \tstruct journal_head *jh;\n+\ttransaction_t *trans = READ_ONCE(jinode->i_transaction);\n \n \tbh = head = folio_buffers(folio);\n \tdo {\n@@ -539,7 +540,7 @@ static bool ext4_journalled_writepage_needs_redirty(struct jbd2_inode *jinode,\n \t\t */\n \t\tjh = bh2jh(bh);\n \t\tif (buffer_dirty(bh) ||\n-\t\t (jh && (jh->b_transaction != jinode->i_transaction ||\n+\t\t (jh && (jh->b_transaction != trans ||\n \t\t\t jh->b_next_transaction)))\n \t\t\treturn true;\n \t} while ((bh = bh->b_this_page) != head);\n@@ -550,12 +551,14 @@ static bool ext4_journalled_writepage_needs_redirty(struct jbd2_inode *jinode,\n static int ext4_journalled_submit_inode_data_buffers(struct jbd2_inode *jinode)\n {\n \tstruct address_space *mapping = jinode->i_vfs_inode->i_mapping;\n+\tloff_t dirty_start = READ_ONCE(jinode->i_dirty_start);\n+\tloff_t dirty_end = READ_ONCE(jinode->i_dirty_end);\n \tstruct writeback_control wbc = {\n-\t\t.sync_mode = WB_SYNC_ALL,\n+\t\t.sync_mode = WB_SYNC_ALL,\n \t\t.nr_to_write = LONG_MAX,\n-\t\t.range_start = jinode->i_dirty_start,\n-\t\t.range_end = jinode->i_dirty_end,\n- };\n+\t\t.range_start = dirty_start,\n+\t\t.range_end = dirty_end,\n+\t};\n \tstruct folio *folio = NULL;\n \tint error;\n \n","prefixes":["2/3"]}