Policy - Foreground GC, LFS and greedy GC mode.
Under this policy, f2fs_gc() loops forever to GC as it doesn't have
enough free segements to proceed and thus it keeps calling gc_more
for the same victim segment. This can happen if the selected victim
segment could not be GC'd due to failed blkaddr validity check i.e.
is_alive() returns false for the blocks set in current validity map.
Fix this by keeping track of such invalid segments and skip those
segments for selection in get_victim_by_default() to avoid endless
GC loop under such error scenarios.
Signed-off-by: Sahitya Tummala <[email protected]>
---
v2: fix as per Chao's suggestion to handle this error case
fs/f2fs/gc.c | 15 ++++++++++++++-
fs/f2fs/segment.c | 5 +++++
fs/f2fs/segment.h | 3 +++
3 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 8974672..321a78a 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
nsearched++;
}
+ /*
+ * skip selecting the invalid segno (that is failed due to block
+ * validity check failed during GC) to avoid endless GC loop in
+ * such cases.
+ */
+ if (test_bit(segno, sm->invalid_segmap))
+ goto next;
+
secno = GET_SEC_FROM_SEG(sbi, segno);
if (sec_usage_check(sbi, secno))
@@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
int off;
int phase = 0;
int submitted = 0;
+ struct sit_info *sit_i = SIT_I(sbi);
start_addr = START_BLOCK(sbi, segno);
@@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
}
/* Get an inode by ino with checking validity */
- if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
+ if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
+ if (!test_and_set_bit(segno, sit_i->invalid_segmap))
+ f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
+ start_addr + off, segno);
continue;
+ }
if (phase == 2) {
f2fs_ra_node_page(sbi, dni.ino);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index a661ac3..d45a1d3 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
return -ENOMEM;
#endif
+ sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
+ if (!sit_i->invalid_segmap)
+ return -ENOMEM;
+
/* init SIT information */
sit_i->s_ops = &default_salloc_ops;
@@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
#ifdef CONFIG_F2FS_CHECK_FS
kvfree(sit_i->sit_bitmap_mir);
#endif
+ kvfree(sit_i->invalid_segmap);
kvfree(sit_i);
}
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index b746028..bc5dbe8 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -246,6 +246,9 @@ struct sit_info {
unsigned long long min_mtime; /* min. modification time */
unsigned long long max_mtime; /* max. modification time */
+ /* list of segments to be ignored by GC in case of errors */
+ unsigned long *invalid_segmap;
+
unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
};
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
Hi Sahitya,
On 2019/8/6 19:19, Sahitya Tummala wrote:
> Policy - Foreground GC, LFS and greedy GC mode.
>
> Under this policy, f2fs_gc() loops forever to GC as it doesn't have
> enough free segements to proceed and thus it keeps calling gc_more
> for the same victim segment. This can happen if the selected victim
> segment could not be GC'd due to failed blkaddr validity check i.e.
> is_alive() returns false for the blocks set in current validity map.
>
> Fix this by keeping track of such invalid segments and skip those
> segments for selection in get_victim_by_default() to avoid endless
> GC loop under such error scenarios.
>
> Signed-off-by: Sahitya Tummala <[email protected]>
> ---
> v2: fix as per Chao's suggestion to handle this error case
>
> fs/f2fs/gc.c | 15 ++++++++++++++-
> fs/f2fs/segment.c | 5 +++++
> fs/f2fs/segment.h | 3 +++
> 3 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 8974672..321a78a 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
> nsearched++;
> }
>
> + /*
> + * skip selecting the invalid segno (that is failed due to block
> + * validity check failed during GC) to avoid endless GC loop in
> + * such cases.
> + */
> + if (test_bit(segno, sm->invalid_segmap))
> + goto next;
> +
> secno = GET_SEC_FROM_SEG(sbi, segno);
>
> if (sec_usage_check(sbi, secno))
> @@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> int off;
> int phase = 0;
> int submitted = 0;
> + struct sit_info *sit_i = SIT_I(sbi);
>
> start_addr = START_BLOCK(sbi, segno);
>
> @@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> }
>
> /* Get an inode by ino with checking validity */
> - if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
> + if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
> + if (!test_and_set_bit(segno, sit_i->invalid_segmap))
> + f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
> + start_addr + off, segno);
Oh, there is some normal cases in is_alive(), such as f2fs_get_node_page() or
f2fs_get_node_info() failure due to no memory, we should bypass such cases. I
guess something like this:
if (source_blkaddr != blkaddr) {
if (unlikely(check_valid_map(sbi, segno, off))) {
if (!test_and_set_bit(segno, sit_i->invalid_segmap)) {
f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
start_addr + off, segno);
set_sbi_flag(sbi, SBI_NEED_FSCK);
}
}
return false;
}
I think this will be safe to call check_valid_map(), because there should be no
race in between is_alive() and update_sit_entry() from all paths due to node
page lock dependence.
One more concern is should we use this under CONFIG_F2FS_CHECK_FS? If there is
actually such a bug can cause data inconsistency, we'd better find the root
cause in debug version.
Thanks,
> continue;
> + }
>
> if (phase == 2) {
> f2fs_ra_node_page(sbi, dni.ino);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index a661ac3..d45a1d3 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
> return -ENOMEM;
> #endif
>
> + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
> + if (!sit_i->invalid_segmap)
> + return -ENOMEM;
> +
> /* init SIT information */
> sit_i->s_ops = &default_salloc_ops;
>
> @@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
> #ifdef CONFIG_F2FS_CHECK_FS
> kvfree(sit_i->sit_bitmap_mir);
> #endif
> + kvfree(sit_i->invalid_segmap);
> kvfree(sit_i);
> }
>
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index b746028..bc5dbe8 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -246,6 +246,9 @@ struct sit_info {
> unsigned long long min_mtime; /* min. modification time */
> unsigned long long max_mtime; /* max. modification time */
>
> + /* list of segments to be ignored by GC in case of errors */
> + unsigned long *invalid_segmap;
> +
> unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
> };
>
>
Hi Chao,
On Wed, Aug 07, 2019 at 10:04:16AM +0800, Chao Yu wrote:
> Hi Sahitya,
>
> On 2019/8/6 19:19, Sahitya Tummala wrote:
> > Policy - Foreground GC, LFS and greedy GC mode.
> >
> > Under this policy, f2fs_gc() loops forever to GC as it doesn't have
> > enough free segements to proceed and thus it keeps calling gc_more
> > for the same victim segment. This can happen if the selected victim
> > segment could not be GC'd due to failed blkaddr validity check i.e.
> > is_alive() returns false for the blocks set in current validity map.
> >
> > Fix this by keeping track of such invalid segments and skip those
> > segments for selection in get_victim_by_default() to avoid endless
> > GC loop under such error scenarios.
> >
> > Signed-off-by: Sahitya Tummala <[email protected]>
> > ---
> > v2: fix as per Chao's suggestion to handle this error case
> >
> > fs/f2fs/gc.c | 15 ++++++++++++++-
> > fs/f2fs/segment.c | 5 +++++
> > fs/f2fs/segment.h | 3 +++
> > 3 files changed, 22 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> > index 8974672..321a78a 100644
> > --- a/fs/f2fs/gc.c
> > +++ b/fs/f2fs/gc.c
> > @@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
> > nsearched++;
> > }
> >
> > + /*
> > + * skip selecting the invalid segno (that is failed due to block
> > + * validity check failed during GC) to avoid endless GC loop in
> > + * such cases.
> > + */
> > + if (test_bit(segno, sm->invalid_segmap))
> > + goto next;
> > +
> > secno = GET_SEC_FROM_SEG(sbi, segno);
> >
> > if (sec_usage_check(sbi, secno))
> > @@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> > int off;
> > int phase = 0;
> > int submitted = 0;
> > + struct sit_info *sit_i = SIT_I(sbi);
> >
> > start_addr = START_BLOCK(sbi, segno);
> >
> > @@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> > }
> >
> > /* Get an inode by ino with checking validity */
> > - if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
> > + if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
> > + if (!test_and_set_bit(segno, sit_i->invalid_segmap))
> > + f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
> > + start_addr + off, segno);
>
> Oh, there is some normal cases in is_alive(), such as f2fs_get_node_page() or
> f2fs_get_node_info() failure due to no memory, we should bypass such cases. I
Oh, yes, I have missed this point.
> guess something like this:
>
> if (source_blkaddr != blkaddr) {
> if (unlikely(check_valid_map(sbi, segno, off))) {
check_valid_map() is validated before is_alive(). So I think this check again
may not be needed. What do you think?
> if (!test_and_set_bit(segno, sit_i->invalid_segmap)) {
> f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
> start_addr + off, segno);
> set_sbi_flag(sbi, SBI_NEED_FSCK);
> }
> }
> return false;
> }
>
> I think this will be safe to call check_valid_map(), because there should be no
> race in between is_alive() and update_sit_entry() from all paths due to node
> page lock dependence.
>
> One more concern is should we use this under CONFIG_F2FS_CHECK_FS? If there is
> actually such a bug can cause data inconsistency, we'd better find the root
> cause in debug version.
>
Yes, I agree with you. I will include this under CONFIG_F2FS_CHECK_FS.
Thanks,
> Thanks,
>
> > continue;
> > + }
> >
> > if (phase == 2) {
> > f2fs_ra_node_page(sbi, dni.ino);
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index a661ac3..d45a1d3 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
> > return -ENOMEM;
> > #endif
> >
> > + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
> > + if (!sit_i->invalid_segmap)
> > + return -ENOMEM;
> > +
> > /* init SIT information */
> > sit_i->s_ops = &default_salloc_ops;
> >
> > @@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
> > #ifdef CONFIG_F2FS_CHECK_FS
> > kvfree(sit_i->sit_bitmap_mir);
> > #endif
> > + kvfree(sit_i->invalid_segmap);
> > kvfree(sit_i);
> > }
> >
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> > index b746028..bc5dbe8 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -246,6 +246,9 @@ struct sit_info {
> > unsigned long long min_mtime; /* min. modification time */
> > unsigned long long max_mtime; /* max. modification time */
> >
> > + /* list of segments to be ignored by GC in case of errors */
> > + unsigned long *invalid_segmap;
> > +
> > unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
> > };
> >
> >
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
Hi Sahitya,
On 2019/8/7 11:24, Sahitya Tummala wrote:
> Hi Chao,
>
> On Wed, Aug 07, 2019 at 10:04:16AM +0800, Chao Yu wrote:
>> Hi Sahitya,
>>
>> On 2019/8/6 19:19, Sahitya Tummala wrote:
>>> Policy - Foreground GC, LFS and greedy GC mode.
>>>
>>> Under this policy, f2fs_gc() loops forever to GC as it doesn't have
>>> enough free segements to proceed and thus it keeps calling gc_more
>>> for the same victim segment. This can happen if the selected victim
>>> segment could not be GC'd due to failed blkaddr validity check i.e.
>>> is_alive() returns false for the blocks set in current validity map.
>>>
>>> Fix this by keeping track of such invalid segments and skip those
>>> segments for selection in get_victim_by_default() to avoid endless
>>> GC loop under such error scenarios.
>>>
>>> Signed-off-by: Sahitya Tummala <[email protected]>
>>> ---
>>> v2: fix as per Chao's suggestion to handle this error case
>>>
>>> fs/f2fs/gc.c | 15 ++++++++++++++-
>>> fs/f2fs/segment.c | 5 +++++
>>> fs/f2fs/segment.h | 3 +++
>>> 3 files changed, 22 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>>> index 8974672..321a78a 100644
>>> --- a/fs/f2fs/gc.c
>>> +++ b/fs/f2fs/gc.c
>>> @@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
>>> nsearched++;
>>> }
>>>
>>> + /*
>>> + * skip selecting the invalid segno (that is failed due to block
>>> + * validity check failed during GC) to avoid endless GC loop in
>>> + * such cases.
>>> + */
>>> + if (test_bit(segno, sm->invalid_segmap))
>>> + goto next;
>>> +
>>> secno = GET_SEC_FROM_SEG(sbi, segno);
>>>
>>> if (sec_usage_check(sbi, secno))
>>> @@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>>> int off;
>>> int phase = 0;
>>> int submitted = 0;
>>> + struct sit_info *sit_i = SIT_I(sbi);
>>>
>>> start_addr = START_BLOCK(sbi, segno);
>>>
>>> @@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
>>> }
>>>
>>> /* Get an inode by ino with checking validity */
>>> - if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
>>> + if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
>>> + if (!test_and_set_bit(segno, sit_i->invalid_segmap))
>>> + f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
>>> + start_addr + off, segno);
>>
>> Oh, there is some normal cases in is_alive(), such as f2fs_get_node_page() or
>> f2fs_get_node_info() failure due to no memory, we should bypass such cases. I
>
> Oh, yes, I have missed this point.
>
>> guess something like this:
>>
>> if (source_blkaddr != blkaddr) {
>> if (unlikely(check_valid_map(sbi, segno, off))) {
>
> check_valid_map() is validated before is_alive(). So I think this check again
> may not be needed. What do you think?
> race in between is_alive() and update_sit_entry()
There will be a race case:
gc_data_segment f2fs_truncate_data_blocks_range
check_valid_map
f2fs_invalidate_blocks
update_sit_entry
f2fs_test_and_clear_bit(, se->cur_valid_map);
unlock_page(node_page)
is_alive
lock_page(node_page)
blkaddr should be NULL and not equal to source_blkaddr, I think this is a normal
case, right?
Thanks,
>
>> if (!test_and_set_bit(segno, sit_i->invalid_segmap)) {
>> f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
>> start_addr + off, segno);
>> set_sbi_flag(sbi, SBI_NEED_FSCK);
>> }
>> }
>> return false;
>> }
>>
>> I think this will be safe to call check_valid_map(), because there should be no
>> race in between is_alive() and update_sit_entry() from all paths due to node
>> page lock dependence.
>>
>> One more concern is should we use this under CONFIG_F2FS_CHECK_FS? If there is
>> actually such a bug can cause data inconsistency, we'd better find the root
>> cause in debug version.
>>
>
> Yes, I agree with you. I will include this under CONFIG_F2FS_CHECK_FS.
>
> Thanks,
>
>> Thanks,
>>
>>> continue;
>>> + }
>>>
>>> if (phase == 2) {
>>> f2fs_ra_node_page(sbi, dni.ino);
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index a661ac3..d45a1d3 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
>>> return -ENOMEM;
>>> #endif
>>>
>>> + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
>>> + if (!sit_i->invalid_segmap)
>>> + return -ENOMEM;
>>> +
>>> /* init SIT information */
>>> sit_i->s_ops = &default_salloc_ops;
>>>
>>> @@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
>>> #ifdef CONFIG_F2FS_CHECK_FS
>>> kvfree(sit_i->sit_bitmap_mir);
>>> #endif
>>> + kvfree(sit_i->invalid_segmap);
>>> kvfree(sit_i);
>>> }
>>>
>>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
>>> index b746028..bc5dbe8 100644
>>> --- a/fs/f2fs/segment.h
>>> +++ b/fs/f2fs/segment.h
>>> @@ -246,6 +246,9 @@ struct sit_info {
>>> unsigned long long min_mtime; /* min. modification time */
>>> unsigned long long max_mtime; /* max. modification time */
>>>
>>> + /* list of segments to be ignored by GC in case of errors */
>>> + unsigned long *invalid_segmap;
>>> +
>>> unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
>>> };
>>>
>>>
>
On Wed, Aug 07, 2019 at 11:37:22AM +0800, Chao Yu wrote:
> Hi Sahitya,
>
> On 2019/8/7 11:24, Sahitya Tummala wrote:
> > Hi Chao,
> >
> > On Wed, Aug 07, 2019 at 10:04:16AM +0800, Chao Yu wrote:
> >> Hi Sahitya,
> >>
> >> On 2019/8/6 19:19, Sahitya Tummala wrote:
> >>> Policy - Foreground GC, LFS and greedy GC mode.
> >>>
> >>> Under this policy, f2fs_gc() loops forever to GC as it doesn't have
> >>> enough free segements to proceed and thus it keeps calling gc_more
> >>> for the same victim segment. This can happen if the selected victim
> >>> segment could not be GC'd due to failed blkaddr validity check i.e.
> >>> is_alive() returns false for the blocks set in current validity map.
> >>>
> >>> Fix this by keeping track of such invalid segments and skip those
> >>> segments for selection in get_victim_by_default() to avoid endless
> >>> GC loop under such error scenarios.
> >>>
> >>> Signed-off-by: Sahitya Tummala <[email protected]>
> >>> ---
> >>> v2: fix as per Chao's suggestion to handle this error case
> >>>
> >>> fs/f2fs/gc.c | 15 ++++++++++++++-
> >>> fs/f2fs/segment.c | 5 +++++
> >>> fs/f2fs/segment.h | 3 +++
> >>> 3 files changed, 22 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> >>> index 8974672..321a78a 100644
> >>> --- a/fs/f2fs/gc.c
> >>> +++ b/fs/f2fs/gc.c
> >>> @@ -382,6 +382,14 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
> >>> nsearched++;
> >>> }
> >>>
> >>> + /*
> >>> + * skip selecting the invalid segno (that is failed due to block
> >>> + * validity check failed during GC) to avoid endless GC loop in
> >>> + * such cases.
> >>> + */
> >>> + if (test_bit(segno, sm->invalid_segmap))
> >>> + goto next;
> >>> +
> >>> secno = GET_SEC_FROM_SEG(sbi, segno);
> >>>
> >>> if (sec_usage_check(sbi, secno))
> >>> @@ -975,6 +983,7 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> >>> int off;
> >>> int phase = 0;
> >>> int submitted = 0;
> >>> + struct sit_info *sit_i = SIT_I(sbi);
> >>>
> >>> start_addr = START_BLOCK(sbi, segno);
> >>>
> >>> @@ -1008,8 +1017,12 @@ static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
> >>> }
> >>>
> >>> /* Get an inode by ino with checking validity */
> >>> - if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
> >>> + if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) {
> >>> + if (!test_and_set_bit(segno, sit_i->invalid_segmap))
> >>> + f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
> >>> + start_addr + off, segno);
> >>
> >> Oh, there is some normal cases in is_alive(), such as f2fs_get_node_page() or
> >> f2fs_get_node_info() failure due to no memory, we should bypass such cases. I
> >
> > Oh, yes, I have missed this point.
> >
> >> guess something like this:
> >>
> >> if (source_blkaddr != blkaddr) {
> >> if (unlikely(check_valid_map(sbi, segno, off))) {
> >
> > check_valid_map() is validated before is_alive(). So I think this check again
> > may not be needed. What do you think?
>
> > race in between is_alive() and update_sit_entry()
>
> There will be a race case:
>
> gc_data_segment f2fs_truncate_data_blocks_range
> check_valid_map
> f2fs_invalidate_blocks
> update_sit_entry
> f2fs_test_and_clear_bit(, se->cur_valid_map);
> unlock_page(node_page)
> is_alive
> lock_page(node_page)
> blkaddr should be NULL and not equal to source_blkaddr, I think this is a normal
> case, right?
>
Got it, thanks for the clarification.
> Thanks,
>
> >
> >> if (!test_and_set_bit(segno, sit_i->invalid_segmap)) {
> >> f2fs_err(sbi, "invalid blkaddr %u in seg %u is found\n",
> >> start_addr + off, segno);
> >> set_sbi_flag(sbi, SBI_NEED_FSCK);
> >> }
> >> }
> >> return false;
> >> }
> >>
> >> I think this will be safe to call check_valid_map(), because there should be no
> >> race in between is_alive() and update_sit_entry() from all paths due to node
> >> page lock dependence.
> >>
> >> One more concern is should we use this under CONFIG_F2FS_CHECK_FS? If there is
> >> actually such a bug can cause data inconsistency, we'd better find the root
> >> cause in debug version.
> >>
> >
> > Yes, I agree with you. I will include this under CONFIG_F2FS_CHECK_FS.
> >
> > Thanks,
> >
> >> Thanks,
> >>
> >>> continue;
> >>> + }
> >>>
> >>> if (phase == 2) {
> >>> f2fs_ra_node_page(sbi, dni.ino);
> >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> >>> index a661ac3..d45a1d3 100644
> >>> --- a/fs/f2fs/segment.c
> >>> +++ b/fs/f2fs/segment.c
> >>> @@ -4017,6 +4017,10 @@ static int build_sit_info(struct f2fs_sb_info *sbi)
> >>> return -ENOMEM;
> >>> #endif
> >>>
> >>> + sit_i->invalid_segmap = f2fs_kvzalloc(sbi, bitmap_size, GFP_KERNEL);
> >>> + if (!sit_i->invalid_segmap)
> >>> + return -ENOMEM;
> >>> +
> >>> /* init SIT information */
> >>> sit_i->s_ops = &default_salloc_ops;
> >>>
> >>> @@ -4518,6 +4522,7 @@ static void destroy_sit_info(struct f2fs_sb_info *sbi)
> >>> #ifdef CONFIG_F2FS_CHECK_FS
> >>> kvfree(sit_i->sit_bitmap_mir);
> >>> #endif
> >>> + kvfree(sit_i->invalid_segmap);
> >>> kvfree(sit_i);
> >>> }
> >>>
> >>> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> >>> index b746028..bc5dbe8 100644
> >>> --- a/fs/f2fs/segment.h
> >>> +++ b/fs/f2fs/segment.h
> >>> @@ -246,6 +246,9 @@ struct sit_info {
> >>> unsigned long long min_mtime; /* min. modification time */
> >>> unsigned long long max_mtime; /* max. modification time */
> >>>
> >>> + /* list of segments to be ignored by GC in case of errors */
> >>> + unsigned long *invalid_segmap;
> >>> +
> >>> unsigned int last_victim[MAX_GC_POLICY]; /* last victim segment # */
> >>> };
> >>>
> >>>
> >
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.