On 2025/2/17 14:59, Zhang Yi wrote:
From: Zhang Yi <yi.zhang@xxxxxxxxxx>
In __jbd2_journal_erase(), the block_stop parameter includes the last
block of a contiguous region; however, the calculation of byte_stop is
incorrect, as it does not account for the bytes in that last block.
Consequently, the page cache is not cleared properly, which occasionally
causes the ext4/050 test to fail.
Since block_stop operates on inclusion semantics, it involves repeated
increments and decrements by 1, significantly increasing the complexity
of the calculations. Optimize the calculation and fix the incorrect
byte_stop by make both block_stop and byte_stop to use exclusion
semantics.
This fixes a failure in fstests ext4/050.
Fixes: 01d5d96542fd ("ext4: add discard/zeroout flags to journal flush")
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
Looks good, thanks for the patch!
Reviewed-by: Baokun Li <libaokun1@xxxxxxxxxx>
---
fs/jbd2/journal.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index d8084b31b361..49a9e99cbc03 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -1965,17 +1965,15 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
return err;
}
- if (block_start == ~0ULL) {
- block_start = phys_block;
- block_stop = block_start - 1;
- }
+ if (block_start == ~0ULL)
+ block_stop = block_start = phys_block;
/*
* last block not contiguous with current block,
* process last contiguous region and return to this block on
* next loop
*/
- if (phys_block != block_stop + 1) {
+ if (phys_block != block_stop) {
block--;
} else {
block_stop++;
@@ -1994,11 +1992,10 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
*/
byte_start = block_start * journal->j_blocksize;
byte_stop = block_stop * journal->j_blocksize;
- byte_count = (block_stop - block_start + 1) *
- journal->j_blocksize;
+ byte_count = (block_stop - block_start) * journal->j_blocksize;
truncate_inode_pages_range(journal->j_dev->bd_mapping,
- byte_start, byte_stop);
+ byte_start, byte_stop - 1);
if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
err = blkdev_issue_discard(journal->j_dev,
@@ -2013,7 +2010,7 @@ static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
}
if (unlikely(err != 0)) {
- pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
+ pr_err("JBD2: (error %d) unable to wipe journal at physical blocks [%llu, %llu)",
err, block_start, block_stop);
return err;
}
