[{"id":3642636,"web_url":"http://patchwork.ozlabs.org/comment/3642636/","msgid":"<4u2l4huoj7zsfy2u37lgdzlmwwdntgqaer7wta7ud3kat7ox2n@oxhbcqryre3r>","list_archive_url":null,"date":"2026-01-28T10:22:30","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":363,"url":"http://patchwork.ozlabs.org/api/people/363/","name":"Jan Kara","email":"jack@suse.cz"},"content":"On Wed 28-01-26 15:45:15, Gerald Yang wrote:\n> When remounting the filesystem to read only in data=journal mode\n> it may dump the following call trace:\n> \n> [ 71.629350] CPU: 0 UID: 0 PID: 177 Comm: kworker/u96:5 Tainted: G E 6.19.0-rc7 #1 PREEMPT(voluntary)\n> [ 71.629352] Tainted: [E]=UNSIGNED_MODULE\n> [ 71.629353] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/LXD, BIOS unknown 2/2/2022\n> [ 71.629354] Workqueue: writeback wb_workfn (flush-7:4)\n> [ 71.629359] RIP: 0010:ext4_journal_check_start+0x8b/0xd0\n> [ 71.629360] Code: 31 ff 45 31 c0 45 31 c9 e9 42 ad c4 00 48 8b 5d f8 b8 fb ff ff ff c9 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b b8 e2 ff ff ff eb c2 0f 0b eb\n> a9 44 8b 42 08 68 c7 53 ce b8\n> [ 71.629361] RSP: 0018:ffffcf32c0fdf6a8 EFLAGS: 00010202\n> [ 71.629364] RAX: ffff8f08c8505000 RBX: ffff8f08c67ee800 RCX: 0000000000000000\n> [ 71.629366] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n> [ 71.629367] RBP: ffffcf32c0fdf6b0 R08: 0000000000000001 R09: 0000000000000000\n> [ 71.629368] R10: ffff8f08db18b3a8 R11: 0000000000000000 R12: 0000000000000000\n> [ 71.629368] R13: 0000000000000002 R14: 0000000000000a48 R15: ffff8f08c67ee800\n> [ 71.629369] FS: 0000000000000000(0000) GS:ffff8f0a7d273000(0000) knlGS:0000000000000000\n> [ 71.629370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n> [ 71.629371] CR2: 00007b66825905cc CR3: 000000011053d004 CR4: 0000000000772ef0\n> [ 71.629374] PKRU: 55555554\n> [ 71.629374] Call Trace:\n> [ 71.629378] \n> [ 71.629382] __ext4_journal_start_sb+0x38/0x1c0\n> [ 71.629383] mpage_prepare_extent_to_map+0x4af/0x580\n> [ 71.629389] ? sbitmap_get+0x73/0x180\n> [ 71.629399] ext4_do_writepages+0x3cc/0x10a0\n> [ 71.629400] ? kvm_sched_clock_read+0x11/0x20\n> [ 71.629409] ext4_writepages+0xc8/0x1b0\n> [ 71.629410] ? ext4_writepages+0xc8/0x1b0\n> [ 71.629411] do_writepages+0xc4/0x180\n> [ 71.629416] __writeback_single_inode+0x45/0x350\n> [ 71.629419] ? _raw_spin_unlock+0xe/0x40\n> [ 71.629423] writeback_sb_inodes+0x260/0x5c0\n> [ 71.629425] ? __schedule+0x4d1/0x1870\n> [ 71.629429] __writeback_inodes_wb+0x54/0x100\n> [ 71.629431] ? queue_io+0x82/0x140\n> [ 71.629433] wb_writeback+0x1ab/0x330\n> [ 71.629448] wb_workfn+0x31d/0x410\n> [ 71.629450] process_one_work+0x191/0x3e0\n> [ 71.629455] worker_thread+0x2e3/0x420\n> \n> This issue can be easily reproduced by:\n> mkdir -p mnt\n> dd if=/dev/zero of=ext4disk bs=1G count=2 oflag=direct\n> mkfs.ext4 ext4disk\n> tune2fs -o journal_data ext4disk\n> mount ext4disk mnt\n> fio --name=fiotest --rw=randwrite --bs=4k --runtime=3 --ioengine=libaio --iodepth=128 --numjobs=4 --filename=mnt/fiotest --filesize=1G --group_reporting\n> mount -o remount,ro ext4disk mnt\n> sync\n> \n> In data=journal mode, metadata and data are both written to the journal\n> first, but for the second write, ext4 relies on the writeback thread to\n> flush the data to the real file location.\n> \n> After the filesystem is remounted to read only, writeback thread still\n> writes data to it and causes the issue. Return early to avoid starting\n> a journal transaction on a read only filesystem, once the filesystem\n> becomes writable again, the write thread will continue writing data.\n> \n> Signed-off-by: Gerald Yang \n\nThanks for the report and the patch! I can indeed reproduce this warning.\nBut the patch itself is certainly not the right fix for this problem.\next4_remount() must make sure there are no dirty pages on the filesystem\nanymore when remounting filesystem read only and it apparently fails to do\nso. In particular it calls sync_filesystem() which should make sure all\ndata is written. So this bug needs more investigation why there are some\ndirty pages left in the inode in data=journal mode because\next4_writepages() should have written them all...\n\n\t\t\t\t\t\t\t\tHonza\n\n> ---\n> fs/ext4/inode.c | 11 +++++++++++\n> 1 file changed, 11 insertions(+)\n> \n> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\n> index 15ba4d42982f..4e3bbf17995e 100644\n> --- a/fs/ext4/inode.c\n> +++ b/fs/ext4/inode.c\n> @@ -2787,6 +2787,17 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)\n> \tif (unlikely(ret))\n> \t\tgoto out_writepages;\n> \n> +\t/*\n> +\t * For data=journal, if the filesystem was remounted read-only,\n> +\t * the writeback thread may still write dirty pages to it.\n> +\t * Return early to avoid starting a journal transaction on a\n> +\t * read-only filesystem.\n> +\t */\n> +\tif (ext4_should_journal_data(inode) && sb_rdonly(inode->i_sb)) {\n> +\t\tret = -EROFS;\n> +\t\tgoto out_writepages;\n> +\t}\n> +\n> \t/*\n> \t * If we have inline data and arrive here, it means that\n> \t * we will soon create the block for the 1st page, so\n> -- \n> 2.43.0\n>","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=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=H9K1vXbg;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=tNx4IiC2;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=K0zjKHly;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=9n8zmuTq;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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But I think your suggestion is the correct way to fix it, I\nwill look into\nwhy ext4_writepages doesn't flush data to real file location after calling\nsync_filesystem and re-submit the patch for review, thanks again.\n\n\nOn Wed, Jan 28, 2026 at 6:22 PM Jan Kara wrote:\n>\n> On Wed 28-01-26 15:45:15, Gerald Yang wrote:\n> > When remounting the filesystem to read only in data=journal mode\n> > it may dump the following call trace:\n> >\n> > [ 71.629350] CPU: 0 UID: 0 PID: 177 Comm: kworker/u96:5 Tainted: G E 6.19.0-rc7 #1 PREEMPT(voluntary)\n> > [ 71.629352] Tainted: [E]=UNSIGNED_MODULE\n> > [ 71.629353] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/LXD, BIOS unknown 2/2/2022\n> > [ 71.629354] Workqueue: writeback wb_workfn (flush-7:4)\n> > [ 71.629359] RIP: 0010:ext4_journal_check_start+0x8b/0xd0\n> > [ 71.629360] Code: 31 ff 45 31 c0 45 31 c9 e9 42 ad c4 00 48 8b 5d f8 b8 fb ff ff ff c9 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b b8 e2 ff ff ff eb c2 0f 0b eb\n> > a9 44 8b 42 08 68 c7 53 ce b8\n> > [ 71.629361] RSP: 0018:ffffcf32c0fdf6a8 EFLAGS: 00010202\n> > [ 71.629364] RAX: ffff8f08c8505000 RBX: ffff8f08c67ee800 RCX: 0000000000000000\n> > [ 71.629366] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n> > [ 71.629367] RBP: ffffcf32c0fdf6b0 R08: 0000000000000001 R09: 0000000000000000\n> > [ 71.629368] R10: ffff8f08db18b3a8 R11: 0000000000000000 R12: 0000000000000000\n> > [ 71.629368] R13: 0000000000000002 R14: 0000000000000a48 R15: ffff8f08c67ee800\n> > [ 71.629369] FS: 0000000000000000(0000) GS:ffff8f0a7d273000(0000) knlGS:0000000000000000\n> > [ 71.629370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n> > [ 71.629371] CR2: 00007b66825905cc CR3: 000000011053d004 CR4: 0000000000772ef0\n> > [ 71.629374] PKRU: 55555554\n> > [ 71.629374] Call Trace:\n> > [ 71.629378] \n> > [ 71.629382] __ext4_journal_start_sb+0x38/0x1c0\n> > [ 71.629383] mpage_prepare_extent_to_map+0x4af/0x580\n> > [ 71.629389] ? sbitmap_get+0x73/0x180\n> > [ 71.629399] ext4_do_writepages+0x3cc/0x10a0\n> > [ 71.629400] ? kvm_sched_clock_read+0x11/0x20\n> > [ 71.629409] ext4_writepages+0xc8/0x1b0\n> > [ 71.629410] ? ext4_writepages+0xc8/0x1b0\n> > [ 71.629411] do_writepages+0xc4/0x180\n> > [ 71.629416] __writeback_single_inode+0x45/0x350\n> > [ 71.629419] ? _raw_spin_unlock+0xe/0x40\n> > [ 71.629423] writeback_sb_inodes+0x260/0x5c0\n> > [ 71.629425] ? __schedule+0x4d1/0x1870\n> > [ 71.629429] __writeback_inodes_wb+0x54/0x100\n> > [ 71.629431] ? queue_io+0x82/0x140\n> > [ 71.629433] wb_writeback+0x1ab/0x330\n> > [ 71.629448] wb_workfn+0x31d/0x410\n> > [ 71.629450] process_one_work+0x191/0x3e0\n> > [ 71.629455] worker_thread+0x2e3/0x420\n> >\n> > This issue can be easily reproduced by:\n> > mkdir -p mnt\n> > dd if=/dev/zero of=ext4disk bs=1G count=2 oflag=direct\n> > mkfs.ext4 ext4disk\n> > tune2fs -o journal_data ext4disk\n> > mount ext4disk mnt\n> > fio --name=fiotest --rw=randwrite --bs=4k --runtime=3 --ioengine=libaio --iodepth=128 --numjobs=4 --filename=mnt/fiotest --filesize=1G --group_reporting\n> > mount -o remount,ro ext4disk mnt\n> > sync\n> >\n> > In data=journal mode, metadata and data are both written to the journal\n> > first, but for the second write, ext4 relies on the writeback thread to\n> > flush the data to the real file location.\n> >\n> > After the filesystem is remounted to read only, writeback thread still\n> > writes data to it and causes the issue. Return early to avoid starting\n> > a journal transaction on a read only filesystem, once the filesystem\n> > becomes writable again, the write thread will continue writing data.\n> >\n> > Signed-off-by: Gerald Yang \n>\n> Thanks for the report and the patch! I can indeed reproduce this warning.\n> But the patch itself is certainly not the right fix for this problem.\n> ext4_remount() must make sure there are no dirty pages on the filesystem\n> anymore when remounting filesystem read only and it apparently fails to do\n> so. In particular it calls sync_filesystem() which should make sure all\n> data is written. So this bug needs more investigation why there are some\n> dirty pages left in the inode in data=journal mode because\n> ext4_writepages() should have written them all...\n>\n> Honza\n>\n> > ---\n> > fs/ext4/inode.c | 11 +++++++++++\n> > 1 file changed, 11 insertions(+)\n> >\n> > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\n> > index 15ba4d42982f..4e3bbf17995e 100644\n> > --- a/fs/ext4/inode.c\n> > +++ b/fs/ext4/inode.c\n> > @@ -2787,6 +2787,17 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)\n> > if (unlikely(ret))\n> > goto out_writepages;\n> >\n> > + /*\n> > + * For data=journal, if the filesystem was remounted read-only,\n> > + * the writeback thread may still write dirty pages to it.\n> > + * Return early to avoid starting a journal transaction on a\n> > + * read-only filesystem.\n> > + */\n> > + if (ext4_should_journal_data(inode) && sb_rdonly(inode->i_sb)) {\n> > + ret = -EROFS;\n> > + goto out_writepages;\n> > + }\n> > +\n> > /*\n> > * If we have inline data and arrive here, it means that\n> > * we will soon create the block for the 1st page, so\n> > --\n> > 2.43.0\n> >\n> --\n> Jan Kara \n> SUSE Labs, CR","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 (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=Id8elMGE;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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Wed, 28 Jan 2026\n 19:31:55 -0800 (PST)"],"Precedence":"bulk","X-Mailing-List":"linux-ext4@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","References":"<20260128074515.2028982-1-gerald.yang@canonical.com>\n <4u2l4huoj7zsfy2u37lgdzlmwwdntgqaer7wta7ud3kat7ox2n@oxhbcqryre3r>","In-Reply-To":"<4u2l4huoj7zsfy2u37lgdzlmwwdntgqaer7wta7ud3kat7ox2n@oxhbcqryre3r>","From":"Gerald Yang ","Date":"Thu, 29 Jan 2026 11:31:43 +0800","X-Gm-Features":"AZwV_QgiXLCXzLcZroT26SBf46ab125vXIwXq813Kw_HAevw8VhGtbd2D0ZTSh0","Message-ID":"\n ","Subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","To":"Jan Kara ","Cc":"tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,\n\tgerald.yang.tw@gmail.com","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-Spam-Status":"No, score=-1.2 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\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"}},{"id":3643236,"web_url":"http://patchwork.ozlabs.org/comment/3643236/","msgid":"","list_archive_url":null,"date":"2026-01-29T09:31:30","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":363,"url":"http://patchwork.ozlabs.org/api/people/363/","name":"Jan Kara","email":"jack@suse.cz"},"content":"On Thu 29-01-26 11:31:43, Gerald Yang wrote:\n> Thanks Jan for the review, originally this issue was observed during reboot\n> because the root filesystem is remounted to read only before shutdown to\n> make sure all data is flushed to disk.\n> We don't see any issue on the machine because the data is persisted to\n> journal. But I think your suggestion is the correct way to fix it, I\n> will look into\n> why ext4_writepages doesn't flush data to real file location after calling\n> sync_filesystem and re-submit the patch for review, thanks again.\n\nFWIW yesterday I did some investigation and it is always the tail (last\nwritten) folio that is somehow kept dirty. In particular at the beginning\nfor ext4_do_writepages() we commit the running transaction and the bh\nattached to the folio is just dirty but by the time we get to\next4_bio_write_folio() to write it, the bh attached to the tail folio is\nalready part of the running transaction again and so ext4_bio_write_folio()\nfails to write it. I didn't figure out how the bh gets reattached to the\ntransaction yet. Now I likely won't be able to dig more into this for a few\ndays so I'm just sharing my findings until now.\n\n\t\t\t\t\t\t\t\tHonza\n\n> On Wed, Jan 28, 2026 at 6:22 PM Jan Kara wrote:\n> >\n> > On Wed 28-01-26 15:45:15, Gerald Yang wrote:\n> > > When remounting the filesystem to read only in data=journal mode\n> > > it may dump the following call trace:\n> > >\n> > > [ 71.629350] CPU: 0 UID: 0 PID: 177 Comm: kworker/u96:5 Tainted: G E 6.19.0-rc7 #1 PREEMPT(voluntary)\n> > > [ 71.629352] Tainted: [E]=UNSIGNED_MODULE\n> > > [ 71.629353] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/LXD, BIOS unknown 2/2/2022\n> > > [ 71.629354] Workqueue: writeback wb_workfn (flush-7:4)\n> > > [ 71.629359] RIP: 0010:ext4_journal_check_start+0x8b/0xd0\n> > > [ 71.629360] Code: 31 ff 45 31 c0 45 31 c9 e9 42 ad c4 00 48 8b 5d f8 b8 fb ff ff ff c9 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b b8 e2 ff ff ff eb c2 0f 0b eb\n> > > a9 44 8b 42 08 68 c7 53 ce b8\n> > > [ 71.629361] RSP: 0018:ffffcf32c0fdf6a8 EFLAGS: 00010202\n> > > [ 71.629364] RAX: ffff8f08c8505000 RBX: ffff8f08c67ee800 RCX: 0000000000000000\n> > > [ 71.629366] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n> > > [ 71.629367] RBP: ffffcf32c0fdf6b0 R08: 0000000000000001 R09: 0000000000000000\n> > > [ 71.629368] R10: ffff8f08db18b3a8 R11: 0000000000000000 R12: 0000000000000000\n> > > [ 71.629368] R13: 0000000000000002 R14: 0000000000000a48 R15: ffff8f08c67ee800\n> > > [ 71.629369] FS: 0000000000000000(0000) GS:ffff8f0a7d273000(0000) knlGS:0000000000000000\n> > > [ 71.629370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n> > > [ 71.629371] CR2: 00007b66825905cc CR3: 000000011053d004 CR4: 0000000000772ef0\n> > > [ 71.629374] PKRU: 55555554\n> > > [ 71.629374] Call Trace:\n> > > [ 71.629378] \n> > > [ 71.629382] __ext4_journal_start_sb+0x38/0x1c0\n> > > [ 71.629383] mpage_prepare_extent_to_map+0x4af/0x580\n> > > [ 71.629389] ? sbitmap_get+0x73/0x180\n> > > [ 71.629399] ext4_do_writepages+0x3cc/0x10a0\n> > > [ 71.629400] ? kvm_sched_clock_read+0x11/0x20\n> > > [ 71.629409] ext4_writepages+0xc8/0x1b0\n> > > [ 71.629410] ? ext4_writepages+0xc8/0x1b0\n> > > [ 71.629411] do_writepages+0xc4/0x180\n> > > [ 71.629416] __writeback_single_inode+0x45/0x350\n> > > [ 71.629419] ? _raw_spin_unlock+0xe/0x40\n> > > [ 71.629423] writeback_sb_inodes+0x260/0x5c0\n> > > [ 71.629425] ? __schedule+0x4d1/0x1870\n> > > [ 71.629429] __writeback_inodes_wb+0x54/0x100\n> > > [ 71.629431] ? queue_io+0x82/0x140\n> > > [ 71.629433] wb_writeback+0x1ab/0x330\n> > > [ 71.629448] wb_workfn+0x31d/0x410\n> > > [ 71.629450] process_one_work+0x191/0x3e0\n> > > [ 71.629455] worker_thread+0x2e3/0x420\n> > >\n> > > This issue can be easily reproduced by:\n> > > mkdir -p mnt\n> > > dd if=/dev/zero of=ext4disk bs=1G count=2 oflag=direct\n> > > mkfs.ext4 ext4disk\n> > > tune2fs -o journal_data ext4disk\n> > > mount ext4disk mnt\n> > > fio --name=fiotest --rw=randwrite --bs=4k --runtime=3 --ioengine=libaio --iodepth=128 --numjobs=4 --filename=mnt/fiotest --filesize=1G --group_reporting\n> > > mount -o remount,ro ext4disk mnt\n> > > sync\n> > >\n> > > In data=journal mode, metadata and data are both written to the journal\n> > > first, but for the second write, ext4 relies on the writeback thread to\n> > > flush the data to the real file location.\n> > >\n> > > After the filesystem is remounted to read only, writeback thread still\n> > > writes data to it and causes the issue. Return early to avoid starting\n> > > a journal transaction on a read only filesystem, once the filesystem\n> > > becomes writable again, the write thread will continue writing data.\n> > >\n> > > Signed-off-by: Gerald Yang \n> >\n> > Thanks for the report and the patch! I can indeed reproduce this warning.\n> > But the patch itself is certainly not the right fix for this problem.\n> > ext4_remount() must make sure there are no dirty pages on the filesystem\n> > anymore when remounting filesystem read only and it apparently fails to do\n> > so. In particular it calls sync_filesystem() which should make sure all\n> > data is written. So this bug needs more investigation why there are some\n> > dirty pages left in the inode in data=journal mode because\n> > ext4_writepages() should have written them all...\n> >\n> > Honza\n> >\n> > > ---\n> > > fs/ext4/inode.c | 11 +++++++++++\n> > > 1 file changed, 11 insertions(+)\n> > >\n> > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\n> > > index 15ba4d42982f..4e3bbf17995e 100644\n> > > --- a/fs/ext4/inode.c\n> > > +++ b/fs/ext4/inode.c\n> > > @@ -2787,6 +2787,17 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)\n> > > if (unlikely(ret))\n> > > goto out_writepages;\n> > >\n> > > + /*\n> > > + * For data=journal, if the filesystem was remounted read-only,\n> > > + * the writeback thread may still write dirty pages to it.\n> > > + * Return early to avoid starting a journal transaction on a\n> > > + * read-only filesystem.\n> > > + */\n> > > + if (ext4_should_journal_data(inode) && sb_rdonly(inode->i_sb)) {\n> > > + ret = -EROFS;\n> > > + goto out_writepages;\n> > > + }\n> > > +\n> > > /*\n> > > * If we have inline data and arrive here, it means that\n> > > * we will soon create the block for the 1st page, so\n> > > --\n> > > 2.43.0\n> > >\n> > --\n> > Jan Kara \n> > SUSE Labs, CR","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=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=CyQvw0P+;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=XrUenqow;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=CyQvw0P+;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=XrUenqow;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"\n ","X-Spamd-Result":"default: False [-2.30 / 50.00];\n\tBAYES_HAM(-3.00)[100.00%];\n\tSUSPICIOUS_RECIPS(1.50)[];\n\tNEURAL_HAM_LONG(-1.00)[-1.000];\n\tMID_RHS_NOT_FQDN(0.50)[];\n\tNEURAL_HAM_SHORT(-0.20)[-1.000];\n\tMIME_GOOD(-0.10)[text/plain];\n\tRCVD_VIA_SMTP_AUTH(0.00)[];\n\tARC_NA(0.00)[];\n\tMISSING_XM_UA(0.00)[];\n\tMIME_TRACE(0.00)[0:+];\n\tFUZZY_RATELIMITED(0.00)[rspamd.com];\n\tTO_DN_SOME(0.00)[];\n\tTAGGED_RCPT(0.00)[];\n\tFREEMAIL_ENVRCPT(0.00)[gmail.com];\n\tRCPT_COUNT_FIVE(0.00)[6];\n\tFROM_HAS_DN(0.00)[];\n\tFREEMAIL_CC(0.00)[suse.cz,mit.edu,dilger.ca,vger.kernel.org,gmail.com];\n\tRCVD_COUNT_THREE(0.00)[3];\n\tFROM_EQ_ENVFROM(0.00)[];\n\tRCVD_TLS_LAST(0.00)[];\n\tTO_MATCH_ENVRCPT_ALL(0.00)[];\n\tDKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519];\n\tDBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,suse.cz:email,imap1.dmz-prg2.suse.org:helo]","X-Spam-Score":"-2.30","X-Spam-Level":"","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"}},{"id":3643824,"web_url":"http://patchwork.ozlabs.org/comment/3643824/","msgid":"","list_archive_url":null,"date":"2026-01-30T11:38:55","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":77781,"url":"http://patchwork.ozlabs.org/api/people/77781/","name":"Gerald Yang","email":"gerald.yang@canonical.com"},"content":"Thanks for sharing the findings, I'd also like to share some findings:\nI tried to figure out why the buffer is dirty after calling sync_filesystem,\nin mpage_prepare_extent_to_map, first I printed folio_test_dirty(folio):\n\nwhile (index <= end)\n ...\n for (i = 0; i < nr_folios; i++) {\n ...\n (print if folio is dirty here)\n\nand actually all folios are clean:\nif (!folio_test_dirty(folio) ||\n ...\n folio_unlock(folio);\n continue; <==== continue here without writing anything\n\nBecause the call trace happens before going into the above while loop:\n\nif (ext4_should_journal_data(mpd->inode)) {\n handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n\nit checks if the file system is read only and dumps the call trace in\next4_journal_check_start, but it doesn't check if there are any real writes\nthat will happen later in the loop.\n\nTo confirm this, first I added 2 more lines in the reproduce script before\nremounting read only:\nsync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n called during remount read only\necho 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\nmount -o remount,ro ext4disk mnt\n\nThen I can no longer reproduce the call trace.\n\nAnother way I tried was to add drop_pagecache_sb in __ext4_remount:\n\nif ((bool)(fc->sb_flags & SB_RDONLY) != sb_rdonly(sb)) {\n ...\n if (fc->sb_flags & SB_RDONLY) {\n err = sync_filesystem(sb);\n if (err < 0)\n goto restore_opts;\n (drop page caches for this file system here)\n\nWith this, I can not reproduce the issue too. But I'm not sure if drop clean\npage cache after sync file system is a proper way to fix the issue, those\npage cache might still be read. Any thoughts?\n\n\nOn Thu, Jan 29, 2026 at 5:31 PM Jan Kara wrote:\n>\n> On Thu 29-01-26 11:31:43, Gerald Yang wrote:\n> > Thanks Jan for the review, originally this issue was observed during reboot\n> > because the root filesystem is remounted to read only before shutdown to\n> > make sure all data is flushed to disk.\n> > We don't see any issue on the machine because the data is persisted to\n> > journal. But I think your suggestion is the correct way to fix it, I\n> > will look into\n> > why ext4_writepages doesn't flush data to real file location after calling\n> > sync_filesystem and re-submit the patch for review, thanks again.\n>\n> FWIW yesterday I did some investigation and it is always the tail (last\n> written) folio that is somehow kept dirty. In particular at the beginning\n> for ext4_do_writepages() we commit the running transaction and the bh\n> attached to the folio is just dirty but by the time we get to\n> ext4_bio_write_folio() to write it, the bh attached to the tail folio is\n> already part of the running transaction again and so ext4_bio_write_folio()\n> fails to write it. I didn't figure out how the bh gets reattached to the\n> transaction yet. Now I likely won't be able to dig more into this for a few\n> days so I'm just sharing my findings until now.\n>\n> Honza\n>\n> > On Wed, Jan 28, 2026 at 6:22 PM Jan Kara wrote:\n> > >\n> > > On Wed 28-01-26 15:45:15, Gerald Yang wrote:\n> > > > When remounting the filesystem to read only in data=journal mode\n> > > > it may dump the following call trace:\n> > > >\n> > > > [ 71.629350] CPU: 0 UID: 0 PID: 177 Comm: kworker/u96:5 Tainted: G E 6.19.0-rc7 #1 PREEMPT(voluntary)\n> > > > [ 71.629352] Tainted: [E]=UNSIGNED_MODULE\n> > > > [ 71.629353] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/LXD, BIOS unknown 2/2/2022\n> > > > [ 71.629354] Workqueue: writeback wb_workfn (flush-7:4)\n> > > > [ 71.629359] RIP: 0010:ext4_journal_check_start+0x8b/0xd0\n> > > > [ 71.629360] Code: 31 ff 45 31 c0 45 31 c9 e9 42 ad c4 00 48 8b 5d f8 b8 fb ff ff ff c9 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b b8 e2 ff ff ff eb c2 0f 0b eb\n> > > > a9 44 8b 42 08 68 c7 53 ce b8\n> > > > [ 71.629361] RSP: 0018:ffffcf32c0fdf6a8 EFLAGS: 00010202\n> > > > [ 71.629364] RAX: ffff8f08c8505000 RBX: ffff8f08c67ee800 RCX: 0000000000000000\n> > > > [ 71.629366] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n> > > > [ 71.629367] RBP: ffffcf32c0fdf6b0 R08: 0000000000000001 R09: 0000000000000000\n> > > > [ 71.629368] R10: ffff8f08db18b3a8 R11: 0000000000000000 R12: 0000000000000000\n> > > > [ 71.629368] R13: 0000000000000002 R14: 0000000000000a48 R15: ffff8f08c67ee800\n> > > > [ 71.629369] FS: 0000000000000000(0000) GS:ffff8f0a7d273000(0000) knlGS:0000000000000000\n> > > > [ 71.629370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n> > > > [ 71.629371] CR2: 00007b66825905cc CR3: 000000011053d004 CR4: 0000000000772ef0\n> > > > [ 71.629374] PKRU: 55555554\n> > > > [ 71.629374] Call Trace:\n> > > > [ 71.629378] \n> > > > [ 71.629382] __ext4_journal_start_sb+0x38/0x1c0\n> > > > [ 71.629383] mpage_prepare_extent_to_map+0x4af/0x580\n> > > > [ 71.629389] ? sbitmap_get+0x73/0x180\n> > > > [ 71.629399] ext4_do_writepages+0x3cc/0x10a0\n> > > > [ 71.629400] ? kvm_sched_clock_read+0x11/0x20\n> > > > [ 71.629409] ext4_writepages+0xc8/0x1b0\n> > > > [ 71.629410] ? ext4_writepages+0xc8/0x1b0\n> > > > [ 71.629411] do_writepages+0xc4/0x180\n> > > > [ 71.629416] __writeback_single_inode+0x45/0x350\n> > > > [ 71.629419] ? _raw_spin_unlock+0xe/0x40\n> > > > [ 71.629423] writeback_sb_inodes+0x260/0x5c0\n> > > > [ 71.629425] ? __schedule+0x4d1/0x1870\n> > > > [ 71.629429] __writeback_inodes_wb+0x54/0x100\n> > > > [ 71.629431] ? queue_io+0x82/0x140\n> > > > [ 71.629433] wb_writeback+0x1ab/0x330\n> > > > [ 71.629448] wb_workfn+0x31d/0x410\n> > > > [ 71.629450] process_one_work+0x191/0x3e0\n> > > > [ 71.629455] worker_thread+0x2e3/0x420\n> > > >\n> > > > This issue can be easily reproduced by:\n> > > > mkdir -p mnt\n> > > > dd if=/dev/zero of=ext4disk bs=1G count=2 oflag=direct\n> > > > mkfs.ext4 ext4disk\n> > > > tune2fs -o journal_data ext4disk\n> > > > mount ext4disk mnt\n> > > > fio --name=fiotest --rw=randwrite --bs=4k --runtime=3 --ioengine=libaio --iodepth=128 --numjobs=4 --filename=mnt/fiotest --filesize=1G --group_reporting\n> > > > mount -o remount,ro ext4disk mnt\n> > > > sync\n> > > >\n> > > > In data=journal mode, metadata and data are both written to the journal\n> > > > first, but for the second write, ext4 relies on the writeback thread to\n> > > > flush the data to the real file location.\n> > > >\n> > > > After the filesystem is remounted to read only, writeback thread still\n> > > > writes data to it and causes the issue. Return early to avoid starting\n> > > > a journal transaction on a read only filesystem, once the filesystem\n> > > > becomes writable again, the write thread will continue writing data.\n> > > >\n> > > > Signed-off-by: Gerald Yang \n> > >\n> > > Thanks for the report and the patch! I can indeed reproduce this warning.\n> > > But the patch itself is certainly not the right fix for this problem.\n> > > ext4_remount() must make sure there are no dirty pages on the filesystem\n> > > anymore when remounting filesystem read only and it apparently fails to do\n> > > so. In particular it calls sync_filesystem() which should make sure all\n> > > data is written. So this bug needs more investigation why there are some\n> > > dirty pages left in the inode in data=journal mode because\n> > > ext4_writepages() should have written them all...\n> > >\n> > > Honza\n> > >\n> > > > ---\n> > > > fs/ext4/inode.c | 11 +++++++++++\n> > > > 1 file changed, 11 insertions(+)\n> > > >\n> > > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c\n> > > > index 15ba4d42982f..4e3bbf17995e 100644\n> > > > --- a/fs/ext4/inode.c\n> > > > +++ b/fs/ext4/inode.c\n> > > > @@ -2787,6 +2787,17 @@ static int ext4_do_writepages(struct mpage_da_data *mpd)\n> > > > if (unlikely(ret))\n> > > > goto out_writepages;\n> > > >\n> > > > + /*\n> > > > + * For data=journal, if the filesystem was remounted read-only,\n> > > > + * the writeback thread may still write dirty pages to it.\n> > > > + * Return early to avoid starting a journal transaction on a\n> > > > + * read-only filesystem.\n> > > > + */\n> > > > + if (ext4_should_journal_data(inode) && sb_rdonly(inode->i_sb)) {\n> > > > + ret = -EROFS;\n> > > > + goto out_writepages;\n> > > > + }\n> > > > +\n> > > > /*\n> > > > * If we have inline data and arrive here, it means that\n> > > > * we will soon create the block for the 1st page, so\n> > > > --\n> > > > 2.43.0\n> > > >\n> > > --\n> > > Jan Kara \n> > > SUSE Labs, CR\n> --\n> Jan Kara \n> SUSE Labs, CR","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 (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=DKP87hE4;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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i < nr_folios; i++) {\n> ...\n> (print if folio is dirty here)\n> \n> and actually all folios are clean:\n> if (!folio_test_dirty(folio) ||\n> ...\n> folio_unlock(folio);\n> continue; <==== continue here without writing anything\n> \n> Because the call trace happens before going into the above while loop:\n> \n> if (ext4_should_journal_data(mpd->inode)) {\n> handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> \n> it checks if the file system is read only and dumps the call trace in\n> ext4_journal_check_start, but it doesn't check if there are any real writes\n> that will happen later in the loop.\n> \n> To confirm this, first I added 2 more lines in the reproduce script before\n> remounting read only:\n> sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> called during remount read only\n> echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> mount -o remount,ro ext4disk mnt\n> \n> Then I can no longer reproduce the call trace.\n\nOK, but ext4_do_writepages() has a check at the beginning:\n\n if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n goto out_writepages;\n\nSo if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\nshould be false and so we shouldn't go further?\n\nIt all looks like some kind of a race because I'm not always able to\nreproduce the problem... I'll try to look more into this.\n\n\t\t\t\t\t\t\t\tHonza","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=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=tDgRFGqX;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=2Yny2qzQ;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=tDgRFGqX;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=2Yny2qzQ;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; helo=mail.ozlabs.org;\n envelope-from=srs0=z/rx=ah=vger.kernel.org=linux-ext4+bounces-13511-patchwork-incoming=ozlabs.org@ozlabs.org;\n receiver=patchwork.ozlabs.org)","gandalf.ozlabs.org;\n arc=pass smtp.remote-ip=\"2600:3c04:e001:36c::12fc:5321\"\n arc.chain=subspace.kernel.org","gandalf.ozlabs.org;\n dmarc=none (p=none dis=none) header.from=suse.cz","gandalf.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=tDgRFGqX;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=2Yny2qzQ;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=tDgRFGqX;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=2Yny2qzQ;\n\tdkim-atps=neutral","gandalf.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"\n ","X-Spam-Score":"-2.51","X-Spamd-Result":"default: False [-2.51 / 50.00];\n\tBAYES_HAM(-3.00)[100.00%];\n\tSUSPICIOUS_RECIPS(1.50)[];\n\tNEURAL_HAM_LONG(-1.00)[-1.000];\n\tMID_RHS_NOT_FQDN(0.50)[];\n\tR_DKIM_ALLOW(-0.20)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519];\n\tNEURAL_HAM_SHORT(-0.20)[-1.000];\n\tMIME_GOOD(-0.10)[text/plain];\n\tMX_GOOD(-0.01)[];\n\tDKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519];\n\tRCVD_COUNT_THREE(0.00)[3];\n\tFUZZY_RATELIMITED(0.00)[rspamd.com];\n\tARC_NA(0.00)[];\n\tSPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from];\n\tRBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from];\n\tTO_DN_SOME(0.00)[];\n\tMIME_TRACE(0.00)[0:+];\n\tFREEMAIL_ENVRCPT(0.00)[gmail.com];\n\tTO_MATCH_ENVRCPT_ALL(0.00)[];\n\tRCPT_COUNT_FIVE(0.00)[6];\n\tRECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received];\n\tFROM_EQ_ENVFROM(0.00)[];\n\tFROM_HAS_DN(0.00)[];\n\tRCVD_TLS_LAST(0.00)[];\n\tTAGGED_RCPT(0.00)[];\n\tMISSING_XM_UA(0.00)[];\n\tRCVD_VIA_SMTP_AUTH(0.00)[];\n\tFREEMAIL_CC(0.00)[suse.cz,mit.edu,dilger.ca,vger.kernel.org,gmail.com];\n\tDKIM_TRACE(0.00)[suse.cz:+];\n\tDBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo,suse.com:email]","X-Spam-Level":"","X-Rspamd-Action":"no action","X-Rspamd-Queue-Id":"933DE5BCC6","X-Rspamd-Server":"rspamd1.dmz-prg2.suse.org","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"}},{"id":3646387,"web_url":"http://patchwork.ozlabs.org/comment/3646387/","msgid":"","list_archive_url":null,"date":"2026-02-05T09:25:39","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":363,"url":"http://patchwork.ozlabs.org/api/people/363/","name":"Jan Kara","email":"jack@suse.cz"},"content":"On Tue 03-02-26 15:50:43, Jan Kara wrote:\n> Hello,\n> \n> On Fri 30-01-26 19:38:55, Gerald Yang wrote:\n> > Thanks for sharing the findings, I'd also like to share some findings:\n> > I tried to figure out why the buffer is dirty after calling sync_filesystem,\n> > in mpage_prepare_extent_to_map, first I printed folio_test_dirty(folio):\n> > \n> > while (index <= end)\n> > ...\n> > for (i = 0; i < nr_folios; i++) {\n> > ...\n> > (print if folio is dirty here)\n> > \n> > and actually all folios are clean:\n> > if (!folio_test_dirty(folio) ||\n> > ...\n> > folio_unlock(folio);\n> > continue; <==== continue here without writing anything\n> > \n> > Because the call trace happens before going into the above while loop:\n> > \n> > if (ext4_should_journal_data(mpd->inode)) {\n> > handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> > \n> > it checks if the file system is read only and dumps the call trace in\n> > ext4_journal_check_start, but it doesn't check if there are any real writes\n> > that will happen later in the loop.\n> > \n> > To confirm this, first I added 2 more lines in the reproduce script before\n> > remounting read only:\n> > sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> > called during remount read only\n> > echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> > mount -o remount,ro ext4disk mnt\n> > \n> > Then I can no longer reproduce the call trace.\n> \n> OK, but ext4_do_writepages() has a check at the beginning:\n> \n> if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n> goto out_writepages;\n> \n> So if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\n> should be false and so we shouldn't go further?\n> \n> It all looks like some kind of a race because I'm not always able to\n> reproduce the problem... I'll try to look more into this.\n\nOK, the race is with checkpointing code writing the buffers while flush\nworker tries to writeback the pages. I've posted a patch which fixes the\nissue for me.\n\n\t\t\t\t\t\t\t\tHonza","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=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=0atXNMF6;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=MF15H2FN;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=0atXNMF6;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=MF15H2FN;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; helo=mail.ozlabs.org;\n envelope-from=srs0=mbz0=aj=vger.kernel.org=linux-ext4+bounces-13541-patchwork-incoming=ozlabs.org@ozlabs.org;\n receiver=patchwork.ozlabs.org)","gandalf.ozlabs.org;\n arc=pass smtp.remote-ip=\"2600:3c09:e001:a7::12fc:5321\"\n arc.chain=subspace.kernel.org","gandalf.ozlabs.org;\n dmarc=none (p=none dis=none) header.from=suse.cz","gandalf.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=0atXNMF6;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=MF15H2FN;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=0atXNMF6;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=MF15H2FN;\n\tdkim-atps=neutral","gandalf.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c09:e001:a7::12fc:5321; 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i < nr_folios; i++) {\n> > > ...\n> > > (print if folio is dirty here)\n> > >\n> > > and actually all folios are clean:\n> > > if (!folio_test_dirty(folio) ||\n> > > ...\n> > > folio_unlock(folio);\n> > > continue; <==== continue here without writing anything\n> > >\n> > > Because the call trace happens before going into the above while loop:\n> > >\n> > > if (ext4_should_journal_data(mpd->inode)) {\n> > > handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> > >\n> > > it checks if the file system is read only and dumps the call trace in\n> > > ext4_journal_check_start, but it doesn't check if there are any real writes\n> > > that will happen later in the loop.\n> > >\n> > > To confirm this, first I added 2 more lines in the reproduce script before\n> > > remounting read only:\n> > > sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> > > called during remount read only\n> > > echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> > > mount -o remount,ro ext4disk mnt\n> > >\n> > > Then I can no longer reproduce the call trace.\n> >\n> > OK, but ext4_do_writepages() has a check at the beginning:\n> >\n> > if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n> > goto out_writepages;\n> >\n> > So if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\n> > should be false and so we shouldn't go further?\n> >\n> > It all looks like some kind of a race because I'm not always able to\n> > reproduce the problem... I'll try to look more into this.\n>\n> OK, the race is with checkpointing code writing the buffers while flush\n> worker tries to writeback the pages. I've posted a patch which fixes the\n> issue for me.\n>\n> Honza\n> --\n> Jan Kara \n> SUSE Labs, CR","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 (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=gaG797Sm;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=150.107.74.76; helo=mail.ozlabs.org;\n envelope-from=srs0=jeo5=aj=vger.kernel.org=linux-ext4+bounces-13545-patchwork-incoming=ozlabs.org@ozlabs.org;\n receiver=patchwork.ozlabs.org)","gandalf.ozlabs.org;\n arc=pass smtp.remote-ip=\"2600:3c0a:e001:db::12fc:5321\"\n arc.chain=\"subspace.kernel.org:google.com\"","gandalf.ozlabs.org;\n dmarc=pass (p=reject dis=none) header.from=canonical.com","gandalf.ozlabs.org;\n\tdkim=pass (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=gaG797Sm;\n\tdkim-atps=neutral","gandalf.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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Thu, 05 Feb 2026\n 04:59:28 -0800 (PST)"],"Precedence":"bulk","X-Mailing-List":"linux-ext4@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","References":"<20260128074515.2028982-1-gerald.yang@canonical.com>\n <4u2l4huoj7zsfy2u37lgdzlmwwdntgqaer7wta7ud3kat7ox2n@oxhbcqryre3r>\n \n \n \n \n ","In-Reply-To":"","From":"Gerald Yang ","Date":"Thu, 5 Feb 2026 20:59:13 +0800","X-Gm-Features":"AZwV_QhwvKyPhKC_AULj0yACRazOcdsNLyJoWYEw-m1ch3bTmpOh67ChjUEbJo4","Message-ID":"\n ","Subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","To":"Jan Kara ","Cc":"tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,\n\tgerald.yang.tw@gmail.com","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-Spam-Status":"No, score=-1.2 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\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"}},{"id":3669420,"web_url":"http://patchwork.ozlabs.org/comment/3669420/","msgid":"","list_archive_url":null,"date":"2026-03-26T01:50:39","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":77781,"url":"http://patchwork.ozlabs.org/api/people/77781/","name":"Gerald Yang","email":"gerald.yang@canonical.com"},"content":"Hi Jan,\n\nI'd like to ask when this will land in upstream kernel? Thanks.\n\nOn Thu, Feb 5, 2026 at 8:59 PM Gerald Yang wrote:\n>\n> Thanks Jan for fixing this issue, I can confirm the patch works for me too.\n>\n>\n> On Thu, Feb 5, 2026 at 5:25 PM Jan Kara wrote:\n> >\n> > On Tue 03-02-26 15:50:43, Jan Kara wrote:\n> > > Hello,\n> > >\n> > > On Fri 30-01-26 19:38:55, Gerald Yang wrote:\n> > > > Thanks for sharing the findings, I'd also like to share some findings:\n> > > > I tried to figure out why the buffer is dirty after calling sync_filesystem,\n> > > > in mpage_prepare_extent_to_map, first I printed folio_test_dirty(folio):\n> > > >\n> > > > while (index <= end)\n> > > > ...\n> > > > for (i = 0; i < nr_folios; i++) {\n> > > > ...\n> > > > (print if folio is dirty here)\n> > > >\n> > > > and actually all folios are clean:\n> > > > if (!folio_test_dirty(folio) ||\n> > > > ...\n> > > > folio_unlock(folio);\n> > > > continue; <==== continue here without writing anything\n> > > >\n> > > > Because the call trace happens before going into the above while loop:\n> > > >\n> > > > if (ext4_should_journal_data(mpd->inode)) {\n> > > > handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> > > >\n> > > > it checks if the file system is read only and dumps the call trace in\n> > > > ext4_journal_check_start, but it doesn't check if there are any real writes\n> > > > that will happen later in the loop.\n> > > >\n> > > > To confirm this, first I added 2 more lines in the reproduce script before\n> > > > remounting read only:\n> > > > sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> > > > called during remount read only\n> > > > echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> > > > mount -o remount,ro ext4disk mnt\n> > > >\n> > > > Then I can no longer reproduce the call trace.\n> > >\n> > > OK, but ext4_do_writepages() has a check at the beginning:\n> > >\n> > > if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n> > > goto out_writepages;\n> > >\n> > > So if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\n> > > should be false and so we shouldn't go further?\n> > >\n> > > It all looks like some kind of a race because I'm not always able to\n> > > reproduce the problem... I'll try to look more into this.\n> >\n> > OK, the race is with checkpointing code writing the buffers while flush\n> > worker tries to writeback the pages. I've posted a patch which fixes the\n> > issue for me.\n> >\n> > Honza\n> > --\n> > Jan Kara \n> > SUSE Labs, CR","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 (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=ZeOYKHlR;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=150.107.74.76; helo=mail.ozlabs.org;\n envelope-from=srs0=iv3y=b2=vger.kernel.org=linux-ext4+bounces-15384-patchwork-incoming=ozlabs.org@ozlabs.org;\n receiver=patchwork.ozlabs.org)","gandalf.ozlabs.org;\n arc=pass smtp.remote-ip=172.105.105.114\n arc.chain=\"subspace.kernel.org:google.com\"","gandalf.ozlabs.org;\n dmarc=pass (p=reject dis=none) header.from=canonical.com","gandalf.ozlabs.org;\n\tdkim=pass (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=ZeOYKHlR;\n\tdkim-atps=neutral","gandalf.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.105.105.114; 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Thanks.\n\nWell, this is more a question to Ted. He didn't pick up the patch [1] to\nhis tree yet. I guess he'll pick it up for the next merge window which will\nstart in two weeks or so.\n\n\t\t\t\t\t\t\t\tHonza\n\n[1] https://lore.kernel.org/linux-ext4/20260205092223.21287-2-jack@suse.cz/\n\n> \n> On Thu, Feb 5, 2026 at 8:59 PM Gerald Yang wrote:\n> >\n> > Thanks Jan for fixing this issue, I can confirm the patch works for me too.\n> >\n> >\n> > On Thu, Feb 5, 2026 at 5:25 PM Jan Kara wrote:\n> > >\n> > > On Tue 03-02-26 15:50:43, Jan Kara wrote:\n> > > > Hello,\n> > > >\n> > > > On Fri 30-01-26 19:38:55, Gerald Yang wrote:\n> > > > > Thanks for sharing the findings, I'd also like to share some findings:\n> > > > > I tried to figure out why the buffer is dirty after calling sync_filesystem,\n> > > > > in mpage_prepare_extent_to_map, first I printed folio_test_dirty(folio):\n> > > > >\n> > > > > while (index <= end)\n> > > > > ...\n> > > > > for (i = 0; i < nr_folios; i++) {\n> > > > > ...\n> > > > > (print if folio is dirty here)\n> > > > >\n> > > > > and actually all folios are clean:\n> > > > > if (!folio_test_dirty(folio) ||\n> > > > > ...\n> > > > > folio_unlock(folio);\n> > > > > continue; <==== continue here without writing anything\n> > > > >\n> > > > > Because the call trace happens before going into the above while loop:\n> > > > >\n> > > > > if (ext4_should_journal_data(mpd->inode)) {\n> > > > > handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> > > > >\n> > > > > it checks if the file system is read only and dumps the call trace in\n> > > > > ext4_journal_check_start, but it doesn't check if there are any real writes\n> > > > > that will happen later in the loop.\n> > > > >\n> > > > > To confirm this, first I added 2 more lines in the reproduce script before\n> > > > > remounting read only:\n> > > > > sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> > > > > called during remount read only\n> > > > > echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> > > > > mount -o remount,ro ext4disk mnt\n> > > > >\n> > > > > Then I can no longer reproduce the call trace.\n> > > >\n> > > > OK, but ext4_do_writepages() has a check at the beginning:\n> > > >\n> > > > if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n> > > > goto out_writepages;\n> > > >\n> > > > So if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\n> > > > should be false and so we shouldn't go further?\n> > > >\n> > > > It all looks like some kind of a race because I'm not always able to\n> > > > reproduce the problem... I'll try to look more into this.\n> > >\n> > > OK, the race is with checkpointing code writing the buffers while flush\n> > > worker tries to writeback the pages. I've posted a patch which fixes the\n> > > issue for me.\n> > >\n> > > Honza\n> > > --\n> > > Jan Kara \n> > > SUSE Labs, CR","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=suse.cz header.i=@suse.cz header.a=rsa-sha256\n header.s=susede2_rsa header.b=CS3CDIxY;\n\tdkim=pass header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=okCg2k1+;\n\tdkim=pass (1024-bit key) header.d=suse.cz header.i=@suse.cz\n header.a=rsa-sha256 header.s=susede2_rsa header.b=CS3CDIxY;\n\tdkim=neutral header.d=suse.cz header.i=@suse.cz header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=okCg2k1+;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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Thanks.\n>\n> Well, this is more a question to Ted. He didn't pick up the patch [1] to\n> his tree yet. I guess he'll pick it up for the next merge window which will\n> start in two weeks or so.\n>\n> Honza\n>\n> [1] https://lore.kernel.org/linux-ext4/20260205092223.21287-2-jack@suse.cz/\n>\n> >\n> > On Thu, Feb 5, 2026 at 8:59 PM Gerald Yang wrote:\n> > >\n> > > Thanks Jan for fixing this issue, I can confirm the patch works for me too.\n> > >\n> > >\n> > > On Thu, Feb 5, 2026 at 5:25 PM Jan Kara wrote:\n> > > >\n> > > > On Tue 03-02-26 15:50:43, Jan Kara wrote:\n> > > > > Hello,\n> > > > >\n> > > > > On Fri 30-01-26 19:38:55, Gerald Yang wrote:\n> > > > > > Thanks for sharing the findings, I'd also like to share some findings:\n> > > > > > I tried to figure out why the buffer is dirty after calling sync_filesystem,\n> > > > > > in mpage_prepare_extent_to_map, first I printed folio_test_dirty(folio):\n> > > > > >\n> > > > > > while (index <= end)\n> > > > > > ...\n> > > > > > for (i = 0; i < nr_folios; i++) {\n> > > > > > ...\n> > > > > > (print if folio is dirty here)\n> > > > > >\n> > > > > > and actually all folios are clean:\n> > > > > > if (!folio_test_dirty(folio) ||\n> > > > > > ...\n> > > > > > folio_unlock(folio);\n> > > > > > continue; <==== continue here without writing anything\n> > > > > >\n> > > > > > Because the call trace happens before going into the above while loop:\n> > > > > >\n> > > > > > if (ext4_should_journal_data(mpd->inode)) {\n> > > > > > handle = ext4_journal_start(mpd->inode, EXT4_HT_WRITE_PAGE,\n> > > > > >\n> > > > > > it checks if the file system is read only and dumps the call trace in\n> > > > > > ext4_journal_check_start, but it doesn't check if there are any real writes\n> > > > > > that will happen later in the loop.\n> > > > > >\n> > > > > > To confirm this, first I added 2 more lines in the reproduce script before\n> > > > > > remounting read only:\n> > > > > > sync <==== it calls ext4_sync_fs to flush all dirty data same as what's\n> > > > > > called during remount read only\n> > > > > > echo 1 > /proc/sys/vm/drop_caches <==== drop clean page cache\n> > > > > > mount -o remount,ro ext4disk mnt\n> > > > > >\n> > > > > > Then I can no longer reproduce the call trace.\n> > > > >\n> > > > > OK, but ext4_do_writepages() has a check at the beginning:\n> > > > >\n> > > > > if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))\n> > > > > goto out_writepages;\n> > > > >\n> > > > > So if there are no dirty pages, mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)\n> > > > > should be false and so we shouldn't go further?\n> > > > >\n> > > > > It all looks like some kind of a race because I'm not always able to\n> > > > > reproduce the problem... I'll try to look more into this.\n> > > >\n> > > > OK, the race is with checkpointing code writing the buffers while flush\n> > > > worker tries to writeback the pages. I've posted a patch which fixes the\n> > > > issue for me.\n> > > >\n> > > > Honza\n> > > > --\n> > > > Jan Kara \n> > > > SUSE Labs, CR\n> --\n> Jan Kara \n> SUSE Labs, CR","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 (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=ArRwD/yx;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; helo=mail.ozlabs.org;\n envelope-from=srs0=dprl=b3=vger.kernel.org=linux-ext4+bounces-15479-patchwork-incoming=ozlabs.org@ozlabs.org;\n receiver=patchwork.ozlabs.org)","gandalf.ozlabs.org;\n arc=pass smtp.remote-ip=172.234.253.10\n arc.chain=\"subspace.kernel.org:google.com\"","gandalf.ozlabs.org;\n dmarc=pass (p=reject dis=none) header.from=canonical.com","gandalf.ozlabs.org;\n\tdkim=pass (4096-bit key;\n unprotected) header.d=canonical.com header.i=@canonical.com\n header.a=rsa-sha256 header.s=20251003 header.b=ArRwD/yx;\n\tdkim-atps=neutral","gandalf.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; 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Fri, 27 Mar 2026\n 00:26:49 -0700 (PDT)"],"Precedence":"bulk","X-Mailing-List":"linux-ext4@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","References":"<20260128074515.2028982-1-gerald.yang@canonical.com>\n <4u2l4huoj7zsfy2u37lgdzlmwwdntgqaer7wta7ud3kat7ox2n@oxhbcqryre3r>\n \n \n \n \n \n \n \n ","In-Reply-To":"","From":"Gerald Yang ","Date":"Fri, 27 Mar 2026 15:26:38 +0800","X-Gm-Features":"AQROBzB_FqDZzyy6_JFgxEEXSM9nQEZ8DhO8qU3I2DMZjmxY-3swjfr9rDM2xWA","Message-ID":"\n ","Subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","To":"Jan Kara ","Cc":"tytso@mit.edu, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,\n\tgerald.yang.tw@gmail.com","Content-Type":"text/plain; charset=\"UTF-8\"","Content-Transfer-Encoding":"quoted-printable","X-Spam-Status":"No, score=-1.2 required=5.0 tests=ARC_SIGNED,ARC_VALID,\n\tDKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DMARC_PASS,\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"}},{"id":3670422,"web_url":"http://patchwork.ozlabs.org/comment/3670422/","msgid":"<20260327154233.GD4383@macsyma.local>","list_archive_url":null,"date":"2026-03-27T15:42:33","subject":"Re: [PATCH] ext4: Fix call trace when remounting to read only in\n data=journal mode","submitter":{"id":350,"url":"http://patchwork.ozlabs.org/api/people/350/","name":"Theodore Tso","email":"tytso@mit.edu"},"content":"On Fri, Mar 27, 2026 at 03:26:38PM +0800, Gerald Yang wrote:\n> \n> Would this be merged into the next merge window?\n> https://lore.kernel.org/linux-ext4/20260205092223.21287-2-jack@suse.cz/\n\nYes, it's in the ext4 git tree already and will be sent along with a\nnumber of other bugfixes to Linus before 7.0 is released.\n\n \t \t\t \t \t - Ted","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 (2048-bit key;\n unprotected) header.d=mit.edu header.i=@mit.edu header.a=rsa-sha256\n header.s=outgoing header.b=W3qP9m+b;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=ozlabs.org\n (client-ip=2404:9400:2221:ea00::3; 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