On 2024/3/25 14:56, Shinichiro Kawasaki wrote:
On Mar 25, 2024 / 11:06, Chao Yu wrote:
On 2024/3/25 10:14, Shinichiro Kawasaki wrote:
On Mar 24, 2024 / 20:13, Chao Yu wrote:
...
Hi Shinichiro,
Can you please check below diff? IIUC, for the case: f2fs_map_blocks()
returns zero blkaddr in non-primary device, which is a verified valid
block address, we'd better to check m_flags & F2FS_MAP_MAPPED instead
of map.m_pblk != NULL_ADDR to decide whether tagging IOMAP_MAPPED flag
or not.
---
fs/f2fs/data.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 6f66e3e4221a..41a56d4298c8 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -4203,7 +4203,7 @@ static int f2fs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
if (WARN_ON_ONCE(map.m_pblk == COMPRESS_ADDR))
return -EINVAL;
- if (map.m_pblk != NULL_ADDR) {
+ if (map.m_flags & F2FS_MAP_MAPPED) {
iomap->length = blks_to_bytes(inode, map.m_len);
iomap->type = IOMAP_MAPPED;
iomap->flags |= IOMAP_F_MERGED;
Thanks Chao, I confirmed that the diff above avoids the WARN and zbd/010
failure. From that point of view, it looks good.
Thank you for the confirmation. :)
One thing I noticed is that the commit message of 8d3c1fa3fa5ea ("f2fs:
don't rely on F2FS_MAP_* in f2fs_iomap_begin") says that f2fs_map_blocks()
might be setting F2FS_MAP_* flag on a hole, and that's why the commit
avoided the F2FS_MAP_MAPPED flag check. So I was not sure if it is the
right thing to reintroduce the flag check.
I didn't see such logic in previous f2fs_map_blocks(, F2FS_GET_BLOCK_DIO) codebase,
I doubt it hits the same case: map.m_pblk is valid zero blkaddr which locates in
the head of secondary device? What do you think?
Quoted commit message from 8d3c1fa3fa5ea:
When testing with a mixed zoned / convention device combination, there
are regular but not 100% reproducible failures in xfstests generic/113
where the __is_valid_data_blkaddr assert hits due to finding a hole.
Previous code:
- if (map.m_flags & (F2FS_MAP_MAPPED | F2FS_MAP_UNWRITTEN)) {
- iomap->length = blks_to_bytes(inode, map.m_len);
- if (map.m_flags & F2FS_MAP_MAPPED) {
- iomap->type = IOMAP_MAPPED;
- iomap->flags |= IOMAP_F_MERGED;
- } else {
- iomap->type = IOMAP_UNWRITTEN;
- }
- if (WARN_ON_ONCE(!__is_valid_data_blkaddr(map.m_pblk)))
- return -EINVAL;
Hmm, I can agree with your guess. Let me add two more points:
1) The commit message says that the generic/113 failure was not 100% recreated.
So it was difficult to confirm that the commit avoided the failure, probably.
2) I ran zbd/010 using the kernel just before the commit 8d3c1fa3fa5ea, and
observed the WARN in the hunk you quoted above.
WARNING: CPU: 1 PID: 1035 at fs/f2fs/data.c:4164 f2fs_iomap_begin+0x19e/0x1b0 [f2fs]
So, it implies that the WARN observed xfstests generic/113 has same failure
scenario as blktests zbd/010, probably.
Yup,
Based on these guesses, I think your fix diff is reasonable. If you post it as a
formal patch, feel free to add my:
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@xxxxxxx>
Thank you for the test!
I've submitted a formal patch, let me know, if you have any comments on it, or want
to update it.
https://lore.kernel.org/linux-f2fs-devel/20240325152623.797099-1-chao@xxxxxxxxxx/
Thanks,
