2022-11-09 19:02:36

by 李扬韬

Subject: [PATCH] f2fs: support fault injection for flush submission error

This patch supports to inject fault into __submit_flush_wait() to
simulate flush cmd io error.

Usage:
a) echo 524288 > /sys/fs/f2fs/<dev>/inject_type or
b) mount -o fault_type=524288 <dev> <mountpoint>

Signed-off-by: Yangtao Li <[email protected]>
---
Documentation/filesystems/f2fs.rst | 1 +
fs/f2fs/f2fs.h | 1 +
fs/f2fs/segment.c | 12 +++++++++++-
fs/f2fs/super.c | 1 +
4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index 6e67c5e6c7c3..316d153cc5fb 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -202,6 +202,7 @@ fault_type=%d Support configuring fault injection type, should be
FAULT_DQUOT_INIT 0x000010000
FAULT_LOCK_OP 0x000020000
FAULT_BLKADDR 0x000040000
+ FAULT_FLUSH 0x000080000
=================== ===========
mode=%s Control block allocation mode which supports "adaptive"
and "lfs". In "lfs" mode, there should be no random
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 04ef4cce3d7f..832baf08ecac 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -61,6 +61,7 @@ enum {
FAULT_DQUOT_INIT,
FAULT_LOCK_OP,
FAULT_BLKADDR,
+ FAULT_FLUSH,
FAULT_MAX,
};

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index aa4be7f25963..61c650db7627 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -486,7 +486,17 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg)
static int __submit_flush_wait(struct f2fs_sb_info *sbi,
struct block_device *bdev)
{
- int ret = blkdev_issue_flush(bdev);
+ int ret;
+
+ if (time_to_inject(sbi, FAULT_FLUSH)) {
+ f2fs_show_injection_info(sbi, FAULT_FLUSH);
+ ret = -EIO;
+ goto submit;
+ }
+
+ ret = blkdev_issue_flush(bdev);
+
+submit:

trace_f2fs_issue_flush(bdev, test_opt(sbi, NOBARRIER),
test_opt(sbi, FLUSH_MERGE), ret);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index a43d8a46a6e5..3d3d22ac527b 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -62,6 +62,7 @@ const char *f2fs_fault_name[FAULT_MAX] = {
[FAULT_DQUOT_INIT] = "dquot initialize",
[FAULT_LOCK_OP] = "lock_op",
[FAULT_BLKADDR] = "invalid blkaddr",
+ [FAULT_FLUSH] = "flush error",
};

void f2fs_build_fault_attr(struct f2fs_sb_info *sbi, unsigned int rate,
--
2.25.1

2022-11-09 20:03:47

by Matthew Wilcox

Subject: Re: [PATCH] f2fs: support fault injection for flush submission error

On Thu, Nov 10, 2022 at 02:35:49AM +0800, Yangtao Li wrote:
> +++ b/fs/f2fs/segment.c
> @@ -486,7 +486,17 @@ void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi, bool from_bg)
> static int __submit_flush_wait(struct f2fs_sb_info *sbi,
> struct block_device *bdev)
> {
> - int ret = blkdev_issue_flush(bdev);
> + int ret;
> +
> + if (time_to_inject(sbi, FAULT_FLUSH)) {
> + f2fs_show_injection_info(sbi, FAULT_FLUSH);
> + ret = -EIO;
> + goto submit;

submit? You don't submit anything at the 'submit' label. it should
be called 'skip' or something. But I think this is just badly written
and you don't need a goto at all.

What I don't understand about this patch is why you want it at all.
What failure are you simulating? It appears to me that you're
simulating a bug in the filesystem, or maybe a bug in the device
firmware. But why do you want to do that?

> + }
> +
> + ret = blkdev_issue_flush(bdev);
> +
> +submit:
>
> trace_f2fs_issue_flush(bdev, test_opt(sbi, NOBARRIER),
> test_opt(sbi, FLUSH_MERGE), ret);
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index a43d8a46a6e5..3d3d22ac527b 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -62,6 +62,7 @@ const char *f2fs_fault_name[FAULT_MAX] = {
> [FAULT_DQUOT_INIT] = "dquot initialize",
> [FAULT_LOCK_OP] = "lock_op",
> [FAULT_BLKADDR] = "invalid blkaddr",
> + [FAULT_FLUSH] = "flush error",
> };
>
> void f2fs_build_fault_attr(struct f2fs_sb_info *sbi, unsigned int rate,
> --
> 2.25.1
>