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Wed, 29 Jul 2026 21:07:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB2701F000E9; Wed, 29 Jul 2026 21:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785359231; bh=oHJbG8Hhgh/0n0sJW+9WheCBkbLkKeS9sY3kDfwRs2E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=k2LHIyQ/MSGGD5CgyX3b9K+A2nV3AjSuSrLDupMRpW4hmYuQZqHJy78IVEKr3jAnV PqKQ+tChyzWLO9MFay/MJ1o3qOgujZpoT5klE97AEh/TBaYc7nCu7UqyRgtsK2rc+W sshUqTMwQfjGV+U2oHWBHa08Wl2PM0K8iYYOwbHEqRE/rFG3WPQBN8owVKg6hAC9YF 35c4Bkzu5JiruXvZO3ppfcQ3FAgArYW/YL7al9YOkClHa8sGfrOYpY+C/P0T6SjLCj zUPCgh4GWovqX5pDZuWoJZsG5T8lj2e4jWq7D1QAIBBDD8hMUNVmkw75RqgsROT2LP KvIZ2yZspN8VQ== Date: Wed, 29 Jul 2026 21:07:09 +0000 To: Chao Yu Message-ID: References: <20260706072606.3709384-1-chao@kernel.org> <9aa5a524-de44-4d07-b6df-70776dd7b0e5@kernel.org> <76a2ad47-bef8-46b6-b9c2-f4f93703ff54@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <76a2ad47-bef8-46b6-b9c2-f4f93703ff54@kernel.org> X-Headers-End: 1wpBUj-0002jO-AJ Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to zero post-EOF data when extending file size X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Jaegeuk Kim via Linux-f2fs-devel Reply-To: Jaegeuk Kim Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, stable@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 07/29, Chao Yu via Linux-f2fs-devel wrote: > On 7/29/26 11:41, Jaegeuk Kim wrote: > > On 07/20, Chao Yu via Linux-f2fs-devel wrote: > >> On 7/16/26 02:05, Jaegeuk Kim wrote: > >>> This causes sysmtem hang during xfstests. > >> > >> Fixed a potential deadlock issue during checkpoint in v2, though I can > >> not reproduce it. > > > > I got this on generic/269 with v2. I'll dequeue the patch first. > > Oh, sorry, will take a look. > > To confirm, do you run generic/269 test w/ fsync_mode=strict mount option? Yes. > > If so, I guess this patch will run out-of-space since we trigger page writeback > of regular inodes during checkpoint(). :/ > > Thanks, > > > > > [ 90.879237] ------------[ cut here ]------------ > > [ 90.881987] kernel BUG at segment.c:2902! > > [ 90.884058] Oops: invalid opcode: 0000 [#1] SMP NOPTI > > [ 90.886628] CPU: 7 UID: 0 PID: 2566 Comm: f2fs_ckpt-252:3 Tainted: G OE 7.2.0-rc5-custom #1 PREEMPT(full) > > [ 90.891533] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE > > [ 90.894647] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 > > [ 90.900014] RIP: 0010:new_curseg+0xa17/0xa60 [f2fs] > > [ 90.902240] Code: 8b 71 48 e9 16 f8 ff ff 4c 8b 69 08 41 8b 84 24 4c 06 00 00 31 d2 41 8b 8c 24 48 06 00 00 f7 f1 89 45 a4 89 f0 e9 e9 fe ff ff <0f> 0b 49 8b 3c 24 68 40 0c 00 00 45 31 c0 31 c9 41 b9 8b ff ff ff > > [ 90.910818] RSP: 0018:ffffd4acc4167670 EFLAGS: 00010293 > > [ 90.913153] RAX: 00000000000000f8 RBX: 0000000000000000 RCX: 0000000000000000 > > [ 90.916400] RDX: ffffffffffffffff RSI: 00000000000000f8 RDI: 00000000000000f8 > > [ 90.919494] RBP: ffffd4acc41676d0 R08: ffff8d640bdab2a0 R09: ffffffffc10673eb > > [ 90.923182] R10: 00000000000000f8 R11: 0000000000000014 R12: ffff8d64892c6000 > > [ 90.926315] R13: ffff8d648c236b80 R14: 00000000000000f8 R15: 0000000000000000 > > [ 90.929430] FS: 0000000000000000(0000) GS:ffff8d6504b73000(0000) knlGS:0000000000000000 > > [ 90.933668] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 90.937206] CR2: 00005577fade9868 CR3: 0000000092d82002 CR4: 0000000000372ef0 > > [ 90.940305] Call Trace: > > [ 90.941486] > > [ 90.942464] f2fs_allocate_data_block+0x69b/0xb10 [f2fs] > > [ 90.944862] do_write_page+0x72/0x360 [f2fs] > > [ 90.946798] ? __folio_start_writeback+0x90/0x1d0 > > [ 90.949485] f2fs_do_write_node_page+0x35/0x70 [f2fs] > > [ 90.952813] __write_node_folio+0x33c/0x640 [f2fs] > > [ 90.955104] ? debug_smp_processor_id+0x17/0x20 > > [ 90.957550] f2fs_sync_node_pages+0x3d8/0x530 [f2fs] > > [ 90.960954] block_operations+0x41d/0x590 [f2fs] > > [ 90.963415] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.966293] f2fs_write_checkpoint+0x15a/0x13c0 [f2fs] > > [ 90.969193] ? update_load_avg+0x79/0x2e0 > > [ 90.971712] ? kvm_clock_get_cycles+0x18/0x40 > > [ 90.974030] ? module_sect_read+0x81/0xc0 > > [ 90.976675] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.980146] __write_checkpoint_sync+0x75/0xb0 [f2fs] > > [ 90.983100] __checkpoint_and_complete_reqs+0x3b/0x110 [f2fs] > > [ 90.986332] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.989853] issue_checkpoint_thread+0x4b/0x100 [f2fs] > > [ 90.992622] ? __pfx_autoremove_wake_function+0x10/0x10 > > [ 90.995875] kthread+0x10a/0x140 > > [ 90.998141] ? __pfx_kthread+0x10/0x10 > > [ 91.000585] ret_from_fork+0x1ef/0x2b0 > > [ 91.002565] ? __pfx_kthread+0x10/0x10 > > [ 91.004510] ret_from_fork_asm+0x1a/0x30 > > > >> > >> Thanks, > >> > >>> > >>> On 07/06, Chao Yu via Linux-f2fs-devel wrote: > >>>> generic/794 4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad) > >>>> --- tests/generic/794.out 2026-06-12 08:46:32.766426241 +0800 > >>>> +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800 > >>>> @@ -1,4 +1,16 @@ > >>>> QA output created by 794 > >>>> append_write > >>>> +FAIL: non-zero data in gap [4080,4096) after shutdown+remount > >>>> +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a >ZZZZZZZZZZZZZZZZ< > >>>> +* > >>>> +001000 > >>>> truncate_up > >>>> ... > >>>> (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad' to see the entire diff) > >>>> Ran: generic/794 > >>>> Failures: generic/794 > >>>> Failed 1 of 1 tests > >>>> > >>>> Steps of generic/794: > >>>> 1. write 4096 bytes to file w/ 0x5a > >>>> 2. use fiemap to get PBA of first block in file > >>>> 3. truncate file to 4080 > >>>> 4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount > >>>> 5. extend filesize via > >>>> a) append 4096 from offset 4096, or > >>>> b) truncate 8192, or > >>>> c) fallocate 4096 from offset 4096 > >>>> 6. verify the gap is zeroed in memory [4080,4096) > >>>> 7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown) > >>>> 8. umount; mount; verify [4080,4096) is zeroed or not. > >>>> > >>>> When extending file size (e.g. via truncate, fallocate, or write) across an > >>>> unaligned EOF boundary, we need to ensure that post-EOF data in the partial > >>>> page is zeroed out in pagecache and marked dirty, meanwhile, tagging the inode > >>>> with FI_ZERO_POST_EOF, so that following checkpoint() and fsync() can persist > >>>> the page contain zeroed data before committing inode w/ updated i_size. > >>>> > >>>> This help to prevent stale disk data beyond the previous EOF from being exposed > >>>> after remounting or crash recovery. > >>>> > >>>> Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile, > >>>> and pinfile has section-aligned filesize, so in Android, there should no problem, > >>>> but for other usage in different environment, let's fix this w/ fsync_mode=strict > >>>> mount option. > >>>> > >>>> Cc: stable@kernel.org > >>>> Signed-off-by: Chao Yu > >>>> --- > >>>> fs/f2fs/checkpoint.c | 4 ++++ > >>>> fs/f2fs/f2fs.h | 1 + > >>>> fs/f2fs/file.c | 35 ++++++++++++++++++++++++++++++++--- > >>>> 3 files changed, 37 insertions(+), 3 deletions(-) > >>>> > >>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >>>> index 064f5b537423..6f486d3a94c7 100644 > >>>> --- a/fs/f2fs/checkpoint.c > >>>> +++ b/fs/f2fs/checkpoint.c > >>>> @@ -1359,6 +1359,10 @@ static int f2fs_sync_inode_meta(struct f2fs_sb_info *sbi) > >>>> inode = igrab(&fi->vfs_inode); > >>>> spin_unlock(&sbi->inode_lock[DIRTY_META]); > >>>> if (inode) { > >>>> + if (is_inode_flag_set(inode, FI_ZERO_POST_EOF)) { > >>>> + filemap_write_and_wait(inode->i_mapping); > >>>> + clear_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> sync_inode_metadata(inode, 0); > >>>> /* it's on eviction */ > >>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > >>>> index 8e2fb0bda467..41be09dad43c 100644 > >>>> --- a/fs/f2fs/f2fs.h > >>>> +++ b/fs/f2fs/f2fs.h > >>>> @@ -939,6 +939,7 @@ enum { > >>>> FI_ATOMIC_REPLACE, /* indicate atomic replace */ > >>>> FI_OPENED_FILE, /* indicate file has been opened */ > >>>> FI_DONATE_FINISHED, /* indicate page donation of file has been finished */ > >>>> + FI_ZERO_POST_EOF, /* indicate unaligned EOF gap was zeroed in pagecache */ > >>>> FI_MAX, /* max flag, never be used */ > >>>> }; > >>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > >>>> index 11cc8d79c235..2e9d585073ec 100644 > >>>> --- a/fs/f2fs/file.c > >>>> +++ b/fs/f2fs/file.c > >>>> @@ -36,21 +36,43 @@ > >>>> #include > >>>> #include > >>>> +static int fill_zero(struct inode *inode, pgoff_t index, > >>>> + loff_t start, loff_t len); > >>>> + > >>>> static void f2fs_zero_post_eof_page(struct inode *inode, > >>>> loff_t new_size, bool lock) > >>>> { > >>>> loff_t old_size = i_size_read(inode); > >>>> + unsigned int offset; > >>>> if (old_size >= new_size) > >>>> return; > >>>> - if (mapping_empty(inode->i_mapping)) > >>>> - return; > >>>> - > >>>> if (lock) > >>>> filemap_invalidate_lock(inode->i_mapping); > >>>> + > >>>> /* zero or drop pages only in range of [old_size, new_size] */ > >>>> truncate_inode_pages_range(inode->i_mapping, old_size, new_size); > >>>> + > >>>> + /* > >>>> + * When expanding an unaligned EOF size, zero post-EOF data in > >>>> + * pagecache and set FI_ZERO_POST_EOF, so following checkpointing > >>>> + * or fsync can persist correct data to disk before committing > >>>> + * inode w/ updated i_size. > >>>> + */ > >>>> + if (F2FS_OPTION(F2FS_I_SB(inode)).fsync_mode != FSYNC_MODE_STRICT) > >>>> + goto out_unlock; > >>>> + > >>>> + offset = old_size & (PAGE_SIZE - 1); > >>>> + if (offset) { > >>>> + unsigned int len = min_t(loff_t, PAGE_SIZE - offset, > >>>> + new_size - old_size); > >>>> + pgoff_t index = old_size >> PAGE_SHIFT; > >>>> + > >>>> + fill_zero(inode, index, offset, len); > >>>> + set_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> +out_unlock: > >>>> if (lock) > >>>> filemap_invalidate_unlock(inode->i_mapping); > >>>> } > >>>> @@ -304,6 +326,13 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end, > >>>> if (S_ISDIR(inode->i_mode)) > >>>> goto go_write; > >>>> + if (is_inode_flag_set(inode, FI_ZERO_POST_EOF)) { > >>>> + ret = filemap_write_and_wait(inode->i_mapping); > >>>> + if (ret) > >>>> + return ret; > >>>> + clear_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> + > >>>> /* if fdatasync is triggered, let's do in-place-update */ > >>>> if (datasync || get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks) > >>>> set_inode_flag(inode, FI_NEED_IPU); > >>>> -- > >>>> 2.49.0 > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Linux-f2fs-devel mailing list > >>>> Linux-f2fs-devel@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > >> > >> > >> > >> _______________________________________________ > >> Linux-f2fs-devel mailing list > >> Linux-f2fs-devel@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 208823A641C for ; 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dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="k2LHIyQ/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB2701F000E9; Wed, 29 Jul 2026 21:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785359231; bh=oHJbG8Hhgh/0n0sJW+9WheCBkbLkKeS9sY3kDfwRs2E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=k2LHIyQ/MSGGD5CgyX3b9K+A2nV3AjSuSrLDupMRpW4hmYuQZqHJy78IVEKr3jAnV PqKQ+tChyzWLO9MFay/MJ1o3qOgujZpoT5klE97AEh/TBaYc7nCu7UqyRgtsK2rc+W sshUqTMwQfjGV+U2oHWBHa08Wl2PM0K8iYYOwbHEqRE/rFG3WPQBN8owVKg6hAC9YF 35c4Bkzu5JiruXvZO3ppfcQ3FAgArYW/YL7al9YOkClHa8sGfrOYpY+C/P0T6SjLCj zUPCgh4GWovqX5pDZuWoJZsG5T8lj2e4jWq7D1QAIBBDD8hMUNVmkw75RqgsROT2LP KvIZ2yZspN8VQ== Date: Wed, 29 Jul 2026 21:07:09 +0000 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, stable@kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to zero post-EOF data when extending file size Message-ID: References: <20260706072606.3709384-1-chao@kernel.org> <9aa5a524-de44-4d07-b6df-70776dd7b0e5@kernel.org> <76a2ad47-bef8-46b6-b9c2-f4f93703ff54@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <76a2ad47-bef8-46b6-b9c2-f4f93703ff54@kernel.org> On 07/29, Chao Yu via Linux-f2fs-devel wrote: > On 7/29/26 11:41, Jaegeuk Kim wrote: > > On 07/20, Chao Yu via Linux-f2fs-devel wrote: > >> On 7/16/26 02:05, Jaegeuk Kim wrote: > >>> This causes sysmtem hang during xfstests. > >> > >> Fixed a potential deadlock issue during checkpoint in v2, though I can > >> not reproduce it. > > > > I got this on generic/269 with v2. I'll dequeue the patch first. > > Oh, sorry, will take a look. > > To confirm, do you run generic/269 test w/ fsync_mode=strict mount option? Yes. > > If so, I guess this patch will run out-of-space since we trigger page writeback > of regular inodes during checkpoint(). :/ > > Thanks, > > > > > [ 90.879237] ------------[ cut here ]------------ > > [ 90.881987] kernel BUG at segment.c:2902! > > [ 90.884058] Oops: invalid opcode: 0000 [#1] SMP NOPTI > > [ 90.886628] CPU: 7 UID: 0 PID: 2566 Comm: f2fs_ckpt-252:3 Tainted: G OE 7.2.0-rc5-custom #1 PREEMPT(full) > > [ 90.891533] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE > > [ 90.894647] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 > > [ 90.900014] RIP: 0010:new_curseg+0xa17/0xa60 [f2fs] > > [ 90.902240] Code: 8b 71 48 e9 16 f8 ff ff 4c 8b 69 08 41 8b 84 24 4c 06 00 00 31 d2 41 8b 8c 24 48 06 00 00 f7 f1 89 45 a4 89 f0 e9 e9 fe ff ff <0f> 0b 49 8b 3c 24 68 40 0c 00 00 45 31 c0 31 c9 41 b9 8b ff ff ff > > [ 90.910818] RSP: 0018:ffffd4acc4167670 EFLAGS: 00010293 > > [ 90.913153] RAX: 00000000000000f8 RBX: 0000000000000000 RCX: 0000000000000000 > > [ 90.916400] RDX: ffffffffffffffff RSI: 00000000000000f8 RDI: 00000000000000f8 > > [ 90.919494] RBP: ffffd4acc41676d0 R08: ffff8d640bdab2a0 R09: ffffffffc10673eb > > [ 90.923182] R10: 00000000000000f8 R11: 0000000000000014 R12: ffff8d64892c6000 > > [ 90.926315] R13: ffff8d648c236b80 R14: 00000000000000f8 R15: 0000000000000000 > > [ 90.929430] FS: 0000000000000000(0000) GS:ffff8d6504b73000(0000) knlGS:0000000000000000 > > [ 90.933668] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 90.937206] CR2: 00005577fade9868 CR3: 0000000092d82002 CR4: 0000000000372ef0 > > [ 90.940305] Call Trace: > > [ 90.941486] > > [ 90.942464] f2fs_allocate_data_block+0x69b/0xb10 [f2fs] > > [ 90.944862] do_write_page+0x72/0x360 [f2fs] > > [ 90.946798] ? __folio_start_writeback+0x90/0x1d0 > > [ 90.949485] f2fs_do_write_node_page+0x35/0x70 [f2fs] > > [ 90.952813] __write_node_folio+0x33c/0x640 [f2fs] > > [ 90.955104] ? debug_smp_processor_id+0x17/0x20 > > [ 90.957550] f2fs_sync_node_pages+0x3d8/0x530 [f2fs] > > [ 90.960954] block_operations+0x41d/0x590 [f2fs] > > [ 90.963415] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.966293] f2fs_write_checkpoint+0x15a/0x13c0 [f2fs] > > [ 90.969193] ? update_load_avg+0x79/0x2e0 > > [ 90.971712] ? kvm_clock_get_cycles+0x18/0x40 > > [ 90.974030] ? module_sect_read+0x81/0xc0 > > [ 90.976675] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.980146] __write_checkpoint_sync+0x75/0xb0 [f2fs] > > [ 90.983100] __checkpoint_and_complete_reqs+0x3b/0x110 [f2fs] > > [ 90.986332] ? __pfx_issue_checkpoint_thread+0x10/0x10 [f2fs] > > [ 90.989853] issue_checkpoint_thread+0x4b/0x100 [f2fs] > > [ 90.992622] ? __pfx_autoremove_wake_function+0x10/0x10 > > [ 90.995875] kthread+0x10a/0x140 > > [ 90.998141] ? __pfx_kthread+0x10/0x10 > > [ 91.000585] ret_from_fork+0x1ef/0x2b0 > > [ 91.002565] ? __pfx_kthread+0x10/0x10 > > [ 91.004510] ret_from_fork_asm+0x1a/0x30 > > > >> > >> Thanks, > >> > >>> > >>> On 07/06, Chao Yu via Linux-f2fs-devel wrote: > >>>> generic/794 4s ... - output mismatch (see /share/git/fstests/results//generic/794.out.bad) > >>>> --- tests/generic/794.out 2026-06-12 08:46:32.766426241 +0800 > >>>> +++ /share/git/fstests/results//generic/794.out.bad 2026-07-05 18:32:55.000000000 +0800 > >>>> @@ -1,4 +1,16 @@ > >>>> QA output created by 794 > >>>> append_write > >>>> +FAIL: non-zero data in gap [4080,4096) after shutdown+remount > >>>> +000000 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a >ZZZZZZZZZZZZZZZZ< > >>>> +* > >>>> +001000 > >>>> truncate_up > >>>> ... > >>>> (Run 'diff -u /share/git/fstests/tests/generic/794.out /share/git/fstests/results//generic/794.out.bad' to see the entire diff) > >>>> Ran: generic/794 > >>>> Failures: generic/794 > >>>> Failed 1 of 1 tests > >>>> > >>>> Steps of generic/794: > >>>> 1. write 4096 bytes to file w/ 0x5a > >>>> 2. use fiemap to get PBA of first block in file > >>>> 3. truncate file to 4080 > >>>> 4. umount; write 4096 bytes to file w/ 0x5a directly via PBA; mount > >>>> 5. extend filesize via > >>>> a) append 4096 from offset 4096, or > >>>> b) truncate 8192, or > >>>> c) fallocate 4096 from offset 4096 > >>>> 6. verify the gap is zeroed in memory [4080,4096) > >>>> 7. sync range 4096 from offset 4096; shutdown -f (flush meta before shutdown) > >>>> 8. umount; mount; verify [4080,4096) is zeroed or not. > >>>> > >>>> When extending file size (e.g. via truncate, fallocate, or write) across an > >>>> unaligned EOF boundary, we need to ensure that post-EOF data in the partial > >>>> page is zeroed out in pagecache and marked dirty, meanwhile, tagging the inode > >>>> with FI_ZERO_POST_EOF, so that following checkpoint() and fsync() can persist > >>>> the page contain zeroed data before committing inode w/ updated i_size. > >>>> > >>>> This help to prevent stale disk data beyond the previous EOF from being exposed > >>>> after remounting or crash recovery. > >>>> > >>>> Since f2fs is a LFS filesystem, we only support direct write via PBA in pinfile, > >>>> and pinfile has section-aligned filesize, so in Android, there should no problem, > >>>> but for other usage in different environment, let's fix this w/ fsync_mode=strict > >>>> mount option. > >>>> > >>>> Cc: stable@kernel.org > >>>> Signed-off-by: Chao Yu > >>>> --- > >>>> fs/f2fs/checkpoint.c | 4 ++++ > >>>> fs/f2fs/f2fs.h | 1 + > >>>> fs/f2fs/file.c | 35 ++++++++++++++++++++++++++++++++--- > >>>> 3 files changed, 37 insertions(+), 3 deletions(-) > >>>> > >>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > >>>> index 064f5b537423..6f486d3a94c7 100644 > >>>> --- a/fs/f2fs/checkpoint.c > >>>> +++ b/fs/f2fs/checkpoint.c > >>>> @@ -1359,6 +1359,10 @@ static int f2fs_sync_inode_meta(struct f2fs_sb_info *sbi) > >>>> inode = igrab(&fi->vfs_inode); > >>>> spin_unlock(&sbi->inode_lock[DIRTY_META]); > >>>> if (inode) { > >>>> + if (is_inode_flag_set(inode, FI_ZERO_POST_EOF)) { > >>>> + filemap_write_and_wait(inode->i_mapping); > >>>> + clear_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> sync_inode_metadata(inode, 0); > >>>> /* it's on eviction */ > >>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > >>>> index 8e2fb0bda467..41be09dad43c 100644 > >>>> --- a/fs/f2fs/f2fs.h > >>>> +++ b/fs/f2fs/f2fs.h > >>>> @@ -939,6 +939,7 @@ enum { > >>>> FI_ATOMIC_REPLACE, /* indicate atomic replace */ > >>>> FI_OPENED_FILE, /* indicate file has been opened */ > >>>> FI_DONATE_FINISHED, /* indicate page donation of file has been finished */ > >>>> + FI_ZERO_POST_EOF, /* indicate unaligned EOF gap was zeroed in pagecache */ > >>>> FI_MAX, /* max flag, never be used */ > >>>> }; > >>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > >>>> index 11cc8d79c235..2e9d585073ec 100644 > >>>> --- a/fs/f2fs/file.c > >>>> +++ b/fs/f2fs/file.c > >>>> @@ -36,21 +36,43 @@ > >>>> #include > >>>> #include > >>>> +static int fill_zero(struct inode *inode, pgoff_t index, > >>>> + loff_t start, loff_t len); > >>>> + > >>>> static void f2fs_zero_post_eof_page(struct inode *inode, > >>>> loff_t new_size, bool lock) > >>>> { > >>>> loff_t old_size = i_size_read(inode); > >>>> + unsigned int offset; > >>>> if (old_size >= new_size) > >>>> return; > >>>> - if (mapping_empty(inode->i_mapping)) > >>>> - return; > >>>> - > >>>> if (lock) > >>>> filemap_invalidate_lock(inode->i_mapping); > >>>> + > >>>> /* zero or drop pages only in range of [old_size, new_size] */ > >>>> truncate_inode_pages_range(inode->i_mapping, old_size, new_size); > >>>> + > >>>> + /* > >>>> + * When expanding an unaligned EOF size, zero post-EOF data in > >>>> + * pagecache and set FI_ZERO_POST_EOF, so following checkpointing > >>>> + * or fsync can persist correct data to disk before committing > >>>> + * inode w/ updated i_size. > >>>> + */ > >>>> + if (F2FS_OPTION(F2FS_I_SB(inode)).fsync_mode != FSYNC_MODE_STRICT) > >>>> + goto out_unlock; > >>>> + > >>>> + offset = old_size & (PAGE_SIZE - 1); > >>>> + if (offset) { > >>>> + unsigned int len = min_t(loff_t, PAGE_SIZE - offset, > >>>> + new_size - old_size); > >>>> + pgoff_t index = old_size >> PAGE_SHIFT; > >>>> + > >>>> + fill_zero(inode, index, offset, len); > >>>> + set_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> +out_unlock: > >>>> if (lock) > >>>> filemap_invalidate_unlock(inode->i_mapping); > >>>> } > >>>> @@ -304,6 +326,13 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end, > >>>> if (S_ISDIR(inode->i_mode)) > >>>> goto go_write; > >>>> + if (is_inode_flag_set(inode, FI_ZERO_POST_EOF)) { > >>>> + ret = filemap_write_and_wait(inode->i_mapping); > >>>> + if (ret) > >>>> + return ret; > >>>> + clear_inode_flag(inode, FI_ZERO_POST_EOF); > >>>> + } > >>>> + > >>>> /* if fdatasync is triggered, let's do in-place-update */ > >>>> if (datasync || get_dirty_pages(inode) <= SM_I(sbi)->min_fsync_blocks) > >>>> set_inode_flag(inode, FI_NEED_IPU); > >>>> -- > >>>> 2.49.0 > >>>> > >>>> > >>>> > >>>> _______________________________________________ > >>>> Linux-f2fs-devel mailing list > >>>> Linux-f2fs-devel@lists.sourceforge.net > >>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > >> > >> > >> > >> _______________________________________________ > >> Linux-f2fs-devel mailing list > >> Linux-f2fs-devel@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel