Hi professor Tytso, we found that logdump has the problem to print circulately in the case which logs area are full of valid transactions. We propose the final solution as follow:
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Date: Thu, 10 Nov 2022 17:09:20 +0800
Subject: [PATCH] debugfs:fix repeated output problem with logdump
Currently, the module of logdump with parameter -O or -On might fall
into printing duplicate transactions circulately.
In fact, it would exit when it check the no magic number in transaction's
block head. But sometimes there hasn't no magic number block spanning
the whole log area so it cause the multi meaningless loop until a new no
magic block was founded.
We record the first blocknr of logs for comparing this value to that when
it meet the block again. If the comparison is equal then it exit immediately.
Signed-off-by: lihaoxiang <lihaoxiang9@xxxxxxxxxx>
---
debugfs/logdump.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/debugfs/logdump.c b/debugfs/logdump.c
index 614414e5..a6d03f5c 100644
--- a/debugfs/logdump.c
+++ b/debugfs/logdump.c
@@ -376,11 +376,14 @@ static void dump_journal(char *cmdname, FILE *out_file,
journal_header_t *header;
tid_t transaction;
unsigned int blocknr = 0;
+ unsigned int last_blocknr;
+ unsigned int first_transaction_blocknr;
int fc_done;
__u64 total_len;
__u32 maxlen;
int64_t cur_counts = 0;
bool exist_no_magic = false;
+ bool reverse_flag = false;
/* First, check to see if there's an ext2 superblock header */
retval = read_journal_block(cmdname, source, 0, buf, 2048);
@@ -470,10 +473,22 @@ static void dump_journal(char *cmdname, FILE *out_file,
blocknr = 1;
}
+ first_transaction_blocknr = blocknr;
+ last_blocknr = blocknr - 1;
+
while (1) {
if (dump_old && (dump_counts != -1) && (cur_counts >= dump_counts))
break;
+ if (last_blocknr != (blocknr - 1))
+ reverse_flag = true;
+ last_blocknr = blocknr;
+
+ if ((blocknr == first_transaction_blocknr) && reverse_flag) {
+ fprintf(out_file, "Dump all %lld journal records.\n", cur_counts);
+ break;
+ }
+
retval = read_journal_block(cmdname, source,
((ext2_loff_t) blocknr) * blocksize,
buf, blocksize);
--
2.37.0.windows.1
