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Date: Wed, 2 Dec 2020 20:01:39 +0800 From: yebin <yebin10@...wei.com> To: Likai <li.kai4@....com>, "Theodore Y. Ts'o" <tytso@....edu>, Jan Kara <jack@...e.cz> CC: "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>, "joseph.qi@...ux.alibaba.com" <joseph.qi@...ux.alibaba.com>, "gechangwei@...e.cn" <gechangwei@...e.cn>, Wangyong <wang.yongD@....com>, Wangxibo <wang.xibo@....com> Subject: Re: [PATCH] jbd2: clear JBD2_ABORT flag before journal_reset to update log tail info when load journal Have you really encountered the problem of file system inconsistency caused by non-replay of logs? (1) if (needs_recovery==0) jbd2_journal_wipe will call jbd2_mark_journal_empty to update s_start and s_sequence. (2) if (needs_recovery == 1) ext4_fill_super: ...... if (needs_recovery) { ext4_msg(sb, KERN_INFO, "recovery complete"); ext4_mark_recovery_complete(sb, es); -->Will update s_start and s_sequence } ...... Recently, I encountered the problem of inconsistent file system data, which may be caused by the log not replaying during fsck. But according to the description of your patch, the s_start and the s_sequence will all be updated. Therefore, I doubt whether the problem you described really exists. On 2020/1/20 14:30, Likai wrote: > On 2020/1/18 5:27, Theodore Y. Ts'o wrote: >> On Tue, Jan 14, 2020 at 11:31:19AM +0100, Jan Kara wrote: >>> Thanks for the patch! Just some small comments below: >>> >>> On Sat 11-01-20 10:25:42, Kai Li wrote: >>>> Fixes: 85e0c4e89c1b "jbd2: if the journal is aborted then don't allow update of the log tail" >>> This tag should come at the bottom of the changelog (close to your >>> Signed-off-by). >>> >>>> If journal is dirty when mount, it will be replayed but jbd2 sb >>>> log tail cannot be updated to mark a new start because >>>> journal->j_flags has already been set with JBD2_ABORT first >>>> in journal_init_common. >>>> When a new transaction is committed, it will be recorded in block 1 >>>> first(journal->j_tail is set to 1 in journal_reset). If emergency >>>> restart again before journal super block is updated unfortunately, >>>> the new recorded trans will not be replayed in the next mount. >>>> It is danerous which may lead to metadata corruption for file system. >>> I'd slightly rephrase the text here so that it is more easily readable and >>> correct some grammar mistakes. Something like: >>> >>> If the journal is dirty when the filesystem is mounted, jbd2 will replay >>> the journal but the journal superblock will not be updated by >>> journal_reset() because JBD2_ABORT flag is still set (it was set in >>> journal_init_common()). This is problematic because when a new transaction >>> is then committed, it will be recorded in block 1 (journal->j_tail was set >>> to 1 in journal_reset()). If unclean shutdown happens again before the >>> journal superblock is updated, the new recorded transaction will not be >>> replayed during the next mount (because of stale sb->s_start and >>> sb->s_sequence values) which can lead to filesystem corruption. >>> >>> Otherwise the patch looks good to me so feel free to add: >>> >>> Reviewed-by: Jan Kara <jack@...e.cz> >>> >>> (again this is added to the bottom of the changelog like the 'Fixes' tag or >>> 'Signed-off-by' tag). >> Thanks, applied with a fixed up commit description. >> >> - Ted >> > Sorry for reply so late due to my business trip recently. This new > comment is ok and more clear. Thanks. > > > > - Kai > > . >
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