Date:   Thu, 10 Sep 2020 12:06:04 +0000
From:   常凤楠 <changfengnan@...vision.com>
To:     "adilger@...ger.ca" <adilger@...ger.ca>
CC:     "darrick.wong@...cle.com" <darrick.wong@...cle.com>,
        "jack@...e.com" <jack@...e.com>,
        "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
        "tytso@....edu" <tytso@....edu>
Subject: [PATCH] jbd2: avoid transaction reuse after reformatting

When format ext4 with lazy_journal_init=1, the previous transaction is still on disk,
it is possible that the previous transaction will be used again during jbd2 recovery.
Because the seed is changed, the CRC check will fail.

Signed-off-by: Fengnan Chang <changfengnan@...vision.com>
---
 fs/jbd2/recovery.c | 60 +++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 54 insertions(+), 6 deletions(-)

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index a4967b27ffb6..8a6bc322a06d 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -33,6 +33,8 @@ struct recovery_info
 intnr_replays;
 intnr_revokes;
 intnr_revoke_hits;
+unsigned long  ri_commit_block;
+__be64  last_trans_commit_time;
 };

 enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY}; @@ -412,7 +414,27 @@ static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
 else
 return tag->t_checksum == cpu_to_be16(csum32);  }
+/*
+ * We check the commit time and compare it with the commit time of
+ * the previous transaction, if it's smaller than previous,
+ * We think it's not belong to same journal.
+ */
+static bool is_same_journal(journal_t *journal, struct buffer_head *bh,
+unsigned long blocknr, __u64 last_commit_sec) {
+unsigned long commit_block = blocknr + count_tags(journal, bh) + 1;
+struct buffer_head *nbh;
+struct commit_header *cbh;
+__u64commit_sec;
+int err = jread(&nbh, journal, commit_block);

+if (err)
+return true;
+
+cbh = (struct commit_header *)nbh->b_data;
+commit_sec = be64_to_cpu(cbh->h_commit_sec);
+
+return commit_sec >= last_commit_sec;
+}
 static int do_one_pass(journal_t *journal,
 struct recovery_info *info, enum passtype pass)  { @@ -514,18 +536,29 @@ static int do_one_pass(journal_t *journal,
 switch(blocktype) {
 case JBD2_DESCRIPTOR_BLOCK:
 /* Verify checksum first */
+if (pass == PASS_SCAN)
+info->ri_commit_block = 0;
+
 if (jbd2_journal_has_csum_v2or3(journal))
 descr_csum_size =
 sizeof(struct jbd2_journal_block_tail);
 if (descr_csum_size > 0 &&
     !jbd2_descriptor_block_csum_verify(journal,
        bh->b_data)) {
-printk(KERN_ERR "JBD2: Invalid checksum "
-       "recovering block %lu in log\n",
+if (is_same_journal(journal, bh, next_log_block-1, info->last_trans_commit_time)) {
+printk(KERN_ERR "JBD2: Invalid checksum recovering block %lu in
+log\n",
        next_log_block);
-err = -EFSBADCRC;
-brelse(bh);
-goto failed;
+err = -EFSBADCRC;
+brelse(bh);
+goto failed;
+} else {
+/*it's not belong to same journal, just end this recovery with success*/
+jbd_debug(1, "JBD2: Invalid checksum found in block %lu in log, but not same journal %d\n",
+       next_log_block, next_commit_ID);
+err = 0;
+brelse(bh);
+goto done;
+}
 }

 /* If it is a valid descriptor block, replay it @@ -688,6 +721,17 @@ static int do_one_pass(journal_t *journal,
  * are present verify them in PASS_SCAN; else not
  * much to do other than move on to the next sequence
  * number. */
+if (pass == PASS_SCAN) {
+struct commit_header *cbh =
+(struct commit_header *)bh->b_data;
+if (info->ri_commit_block) {
+jbd_debug(1, "invalid commit block found in %lu, stop here.\n", next_log_block);
+brelse(bh);
+goto done;
+}
+info->ri_commit_block = next_log_block;
+info->last_trans_commit_time = be64_to_cpu(cbh->h_commit_sec);
+}
 if (pass == PASS_SCAN &&
     jbd2_has_feature_checksum(journal)) {
 int chksum_err, chksum_seen;
@@ -761,7 +805,11 @@ static int do_one_pass(journal_t *journal,
 brelse(bh);
 continue;
 }
-
+if (pass != PASS_SCAN && info->ri_commit_block) {
+jbd_debug(1, "invalid revoke block found in %lu, stop here.\n", next_log_block);
+brelse(bh);
+goto done;
+}
 err = scan_revoke_records(journal, bh,
   next_commit_ID, info);
 brelse(bh);
--
2.27.0.windows.1



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