* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
@ 2020-05-28 19:18 ` Jaegeuk Kim
0 siblings, 0 replies; 14+ messages in thread
From: Jaegeuk Kim @ 2020-05-28 19:18 UTC (permalink / raw)
To: Chao Yu; +Cc: Sahitya Tummala, linux-f2fs-devel, linux-kernel
On 05/28, Chao Yu wrote:
> On 2020/5/28 10:45, Chao Yu wrote:
> > On 2020/5/27 10:20, Sahitya Tummala wrote:
> >> In case a compressed file is getting overwritten, the current retry
> >> logic doesn't include the current page to be retried now as it sets
> >> the new start index as 0 and new end index as writeback_index - 1.
> >> This causes the corresponding cluster to be uncompressed and written
> >> as normal pages without compression. Fix this by allowing writeback to
> >> be retried for the current page as well (in case of compressed page
> >> getting retried due to index mismatch with cluster index). So that
> >> this cluster can be written compressed in case of overwrite.
> >>
> >> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> >> ---
> >> 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 4af5fcd..bfd1df4 100644
> >> --- a/fs/f2fs/data.c
> >> +++ b/fs/f2fs/data.c
> >> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> >> if ((!cycled && !done) || retry) {
> >
> > IMO, we add retry logic in wrong place, you can see that cycled value is
> > zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
> >
> > However if retry is true and wbc->range_cyclic is false, then writeback_index
> > would be uninitialized variable.
> >
> > Thoughts?
> >
> > Thanks,
> >
> >> cycled = 1;
> >> index = 0;
> >> - end = writeback_index - 1;
>
> BTW, I notice that range_cyclic writeback flow was refactored in below commit,
> and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
> I guess we need follow that change.
>
> 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
Is that something like this?
---
fs/f2fs/data.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 48a622b95b76e..28fcdf0d4dcb9 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
pgoff_t index;
pgoff_t end; /* Inclusive */
pgoff_t done_index;
- int cycled;
int range_whole = 0;
xa_mark_t tag;
int nwritten = 0;
@@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
if (wbc->range_cyclic) {
writeback_index = mapping->writeback_index; /* prev offset */
index = writeback_index;
- if (index == 0)
- cycled = 1;
- else
- cycled = 0;
end = -1;
} else {
index = wbc->range_start >> PAGE_SHIFT;
end = wbc->range_end >> PAGE_SHIFT;
if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
range_whole = 1;
- cycled = 1; /* ignore range_cyclic tests */
}
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
tag = PAGECACHE_TAG_TOWRITE;
@@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
}
}
#endif
- if ((!cycled && !done) || retry) {
- cycled = 1;
+ if (retry) {
index = 0;
- end = writeback_index - 1;
+ end = -1;
goto retry;
}
if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
--
2.27.0.rc0.183.gde8f92d652-goog
^ permalink raw reply related [flat|nested] 14+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
2020-05-28 19:18 ` Jaegeuk Kim
@ 2020-06-01 9:15 ` Sahitya Tummala
-1 siblings, 0 replies; 14+ messages in thread
From: Sahitya Tummala @ 2020-06-01 9:15 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
Hi Chao,
Can you please help review below diff given by Jaegeuk?
If it looks good, I can send a v2.
Thanks,
On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
> On 05/28, Chao Yu wrote:
> > On 2020/5/28 10:45, Chao Yu wrote:
> > > On 2020/5/27 10:20, Sahitya Tummala wrote:
> > >> In case a compressed file is getting overwritten, the current retry
> > >> logic doesn't include the current page to be retried now as it sets
> > >> the new start index as 0 and new end index as writeback_index - 1.
> > >> This causes the corresponding cluster to be uncompressed and written
> > >> as normal pages without compression. Fix this by allowing writeback to
> > >> be retried for the current page as well (in case of compressed page
> > >> getting retried due to index mismatch with cluster index). So that
> > >> this cluster can be written compressed in case of overwrite.
> > >>
> > >> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > >> ---
> > >> 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 4af5fcd..bfd1df4 100644
> > >> --- a/fs/f2fs/data.c
> > >> +++ b/fs/f2fs/data.c
> > >> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >> if ((!cycled && !done) || retry) {
> > >
> > > IMO, we add retry logic in wrong place, you can see that cycled value is
> > > zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
> > >
> > > However if retry is true and wbc->range_cyclic is false, then writeback_index
> > > would be uninitialized variable.
> > >
> > > Thoughts?
> > >
> > > Thanks,
> > >
> > >> cycled = 1;
> > >> index = 0;
> > >> - end = writeback_index - 1;
> >
> > BTW, I notice that range_cyclic writeback flow was refactored in below commit,
> > and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
> > I guess we need follow that change.
> >
> > 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>
> Is that something like this?
>
> ---
> fs/f2fs/data.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 48a622b95b76e..28fcdf0d4dcb9 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> pgoff_t index;
> pgoff_t end; /* Inclusive */
> pgoff_t done_index;
> - int cycled;
> int range_whole = 0;
> xa_mark_t tag;
> int nwritten = 0;
> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> if (wbc->range_cyclic) {
> writeback_index = mapping->writeback_index; /* prev offset */
> index = writeback_index;
> - if (index == 0)
> - cycled = 1;
> - else
> - cycled = 0;
> end = -1;
> } else {
> index = wbc->range_start >> PAGE_SHIFT;
> end = wbc->range_end >> PAGE_SHIFT;
> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> range_whole = 1;
> - cycled = 1; /* ignore range_cyclic tests */
> }
> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> tag = PAGECACHE_TAG_TOWRITE;
> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> }
> }
> #endif
> - if ((!cycled && !done) || retry) {
> - cycled = 1;
> + if (retry) {
> index = 0;
> - end = writeback_index - 1;
> + end = -1;
> goto retry;
> }
> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
> --
> 2.27.0.rc0.183.gde8f92d652-goog
>
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
@ 2020-06-01 9:15 ` Sahitya Tummala
0 siblings, 0 replies; 14+ messages in thread
From: Sahitya Tummala @ 2020-06-01 9:15 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: Chao Yu, linux-f2fs-devel, linux-kernel, stummala
Hi Chao,
Can you please help review below diff given by Jaegeuk?
If it looks good, I can send a v2.
Thanks,
On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
> On 05/28, Chao Yu wrote:
> > On 2020/5/28 10:45, Chao Yu wrote:
> > > On 2020/5/27 10:20, Sahitya Tummala wrote:
> > >> In case a compressed file is getting overwritten, the current retry
> > >> logic doesn't include the current page to be retried now as it sets
> > >> the new start index as 0 and new end index as writeback_index - 1.
> > >> This causes the corresponding cluster to be uncompressed and written
> > >> as normal pages without compression. Fix this by allowing writeback to
> > >> be retried for the current page as well (in case of compressed page
> > >> getting retried due to index mismatch with cluster index). So that
> > >> this cluster can be written compressed in case of overwrite.
> > >>
> > >> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > >> ---
> > >> 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 4af5fcd..bfd1df4 100644
> > >> --- a/fs/f2fs/data.c
> > >> +++ b/fs/f2fs/data.c
> > >> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >> if ((!cycled && !done) || retry) {
> > >
> > > IMO, we add retry logic in wrong place, you can see that cycled value is
> > > zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
> > >
> > > However if retry is true and wbc->range_cyclic is false, then writeback_index
> > > would be uninitialized variable.
> > >
> > > Thoughts?
> > >
> > > Thanks,
> > >
> > >> cycled = 1;
> > >> index = 0;
> > >> - end = writeback_index - 1;
> >
> > BTW, I notice that range_cyclic writeback flow was refactored in below commit,
> > and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
> > I guess we need follow that change.
> >
> > 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>
> Is that something like this?
>
> ---
> fs/f2fs/data.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 48a622b95b76e..28fcdf0d4dcb9 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> pgoff_t index;
> pgoff_t end; /* Inclusive */
> pgoff_t done_index;
> - int cycled;
> int range_whole = 0;
> xa_mark_t tag;
> int nwritten = 0;
> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> if (wbc->range_cyclic) {
> writeback_index = mapping->writeback_index; /* prev offset */
> index = writeback_index;
> - if (index == 0)
> - cycled = 1;
> - else
> - cycled = 0;
> end = -1;
> } else {
> index = wbc->range_start >> PAGE_SHIFT;
> end = wbc->range_end >> PAGE_SHIFT;
> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> range_whole = 1;
> - cycled = 1; /* ignore range_cyclic tests */
> }
> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> tag = PAGECACHE_TAG_TOWRITE;
> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> }
> }
> #endif
> - if ((!cycled && !done) || retry) {
> - cycled = 1;
> + if (retry) {
> index = 0;
> - end = writeback_index - 1;
> + end = -1;
> goto retry;
> }
> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
> --
> 2.27.0.rc0.183.gde8f92d652-goog
>
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
2020-05-28 19:18 ` Jaegeuk Kim
@ 2020-06-01 9:20 ` Sahitya Tummala
-1 siblings, 0 replies; 14+ messages in thread
From: Sahitya Tummala @ 2020-06-01 9:20 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
Hi Chao,
Can you please help review the diff given by Jaegeuk below?
If it looks good, I can post a v2.
Thanks,
On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
> On 05/28, Chao Yu wrote:
> > On 2020/5/28 10:45, Chao Yu wrote:
> > > On 2020/5/27 10:20, Sahitya Tummala wrote:
> > >> In case a compressed file is getting overwritten, the current retry
> > >> logic doesn't include the current page to be retried now as it sets
> > >> the new start index as 0 and new end index as writeback_index - 1.
> > >> This causes the corresponding cluster to be uncompressed and written
> > >> as normal pages without compression. Fix this by allowing writeback to
> > >> be retried for the current page as well (in case of compressed page
> > >> getting retried due to index mismatch with cluster index). So that
> > >> this cluster can be written compressed in case of overwrite.
> > >>
> > >> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > >> ---
> > >> 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 4af5fcd..bfd1df4 100644
> > >> --- a/fs/f2fs/data.c
> > >> +++ b/fs/f2fs/data.c
> > >> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >> if ((!cycled && !done) || retry) {
> > >
> > > IMO, we add retry logic in wrong place, you can see that cycled value is
> > > zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
> > >
> > > However if retry is true and wbc->range_cyclic is false, then writeback_index
> > > would be uninitialized variable.
> > >
> > > Thoughts?
> > >
> > > Thanks,
> > >
> > >> cycled = 1;
> > >> index = 0;
> > >> - end = writeback_index - 1;
> >
> > BTW, I notice that range_cyclic writeback flow was refactored in below commit,
> > and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
> > I guess we need follow that change.
> >
> > 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>
> Is that something like this?
>
> ---
> fs/f2fs/data.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 48a622b95b76e..28fcdf0d4dcb9 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> pgoff_t index;
> pgoff_t end; /* Inclusive */
> pgoff_t done_index;
> - int cycled;
> int range_whole = 0;
> xa_mark_t tag;
> int nwritten = 0;
> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> if (wbc->range_cyclic) {
> writeback_index = mapping->writeback_index; /* prev offset */
> index = writeback_index;
> - if (index == 0)
> - cycled = 1;
> - else
> - cycled = 0;
> end = -1;
> } else {
> index = wbc->range_start >> PAGE_SHIFT;
> end = wbc->range_end >> PAGE_SHIFT;
> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> range_whole = 1;
> - cycled = 1; /* ignore range_cyclic tests */
> }
> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> tag = PAGECACHE_TAG_TOWRITE;
> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> }
> }
> #endif
> - if ((!cycled && !done) || retry) {
> - cycled = 1;
> + if (retry) {
> index = 0;
> - end = writeback_index - 1;
> + end = -1;
> goto retry;
> }
> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
> --
> 2.27.0.rc0.183.gde8f92d652-goog
>
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
@ 2020-06-01 9:20 ` Sahitya Tummala
0 siblings, 0 replies; 14+ messages in thread
From: Sahitya Tummala @ 2020-06-01 9:20 UTC (permalink / raw)
To: Jaegeuk Kim; +Cc: Chao Yu, linux-f2fs-devel, linux-kernel, stummala
Hi Chao,
Can you please help review the diff given by Jaegeuk below?
If it looks good, I can post a v2.
Thanks,
On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
> On 05/28, Chao Yu wrote:
> > On 2020/5/28 10:45, Chao Yu wrote:
> > > On 2020/5/27 10:20, Sahitya Tummala wrote:
> > >> In case a compressed file is getting overwritten, the current retry
> > >> logic doesn't include the current page to be retried now as it sets
> > >> the new start index as 0 and new end index as writeback_index - 1.
> > >> This causes the corresponding cluster to be uncompressed and written
> > >> as normal pages without compression. Fix this by allowing writeback to
> > >> be retried for the current page as well (in case of compressed page
> > >> getting retried due to index mismatch with cluster index). So that
> > >> this cluster can be written compressed in case of overwrite.
> > >>
> > >> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
> > >> ---
> > >> 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 4af5fcd..bfd1df4 100644
> > >> --- a/fs/f2fs/data.c
> > >> +++ b/fs/f2fs/data.c
> > >> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> > >> if ((!cycled && !done) || retry) {
> > >
> > > IMO, we add retry logic in wrong place, you can see that cycled value is
> > > zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
> > >
> > > However if retry is true and wbc->range_cyclic is false, then writeback_index
> > > would be uninitialized variable.
> > >
> > > Thoughts?
> > >
> > > Thanks,
> > >
> > >> cycled = 1;
> > >> index = 0;
> > >> - end = writeback_index - 1;
> >
> > BTW, I notice that range_cyclic writeback flow was refactored in below commit,
> > and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
> > I guess we need follow that change.
> >
> > 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>
> Is that something like this?
>
> ---
> fs/f2fs/data.c | 11 ++---------
> 1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 48a622b95b76e..28fcdf0d4dcb9 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> pgoff_t index;
> pgoff_t end; /* Inclusive */
> pgoff_t done_index;
> - int cycled;
> int range_whole = 0;
> xa_mark_t tag;
> int nwritten = 0;
> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> if (wbc->range_cyclic) {
> writeback_index = mapping->writeback_index; /* prev offset */
> index = writeback_index;
> - if (index == 0)
> - cycled = 1;
> - else
> - cycled = 0;
> end = -1;
> } else {
> index = wbc->range_start >> PAGE_SHIFT;
> end = wbc->range_end >> PAGE_SHIFT;
> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
> range_whole = 1;
> - cycled = 1; /* ignore range_cyclic tests */
> }
> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
> tag = PAGECACHE_TAG_TOWRITE;
> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
> }
> }
> #endif
> - if ((!cycled && !done) || retry) {
> - cycled = 1;
> + if (retry) {
> index = 0;
> - end = writeback_index - 1;
> + end = -1;
> goto retry;
> }
> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
> --
> 2.27.0.rc0.183.gde8f92d652-goog
>
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
2020-06-01 9:20 ` Sahitya Tummala
@ 2020-06-01 11:43 ` Chao Yu
-1 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2020-06-01 11:43 UTC (permalink / raw)
To: Sahitya Tummala, Jaegeuk Kim; +Cc: linux-kernel, linux-f2fs-devel
On 2020/6/1 17:20, Sahitya Tummala wrote:
> Hi Chao,
>
> Can you please help review the diff given by Jaegeuk below?
> If it looks good, I can post a v2.
Oops, I missed to review that patch...
>
> Thanks,
>
> On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
>> On 05/28, Chao Yu wrote:
>>> On 2020/5/28 10:45, Chao Yu wrote:
>>>> On 2020/5/27 10:20, Sahitya Tummala wrote:
>>>>> In case a compressed file is getting overwritten, the current retry
>>>>> logic doesn't include the current page to be retried now as it sets
>>>>> the new start index as 0 and new end index as writeback_index - 1.
>>>>> This causes the corresponding cluster to be uncompressed and written
>>>>> as normal pages without compression. Fix this by allowing writeback to
>>>>> be retried for the current page as well (in case of compressed page
>>>>> getting retried due to index mismatch with cluster index). So that
>>>>> this cluster can be written compressed in case of overwrite.
>>>>>
>>>>> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
>>>>> ---
>>>>> 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 4af5fcd..bfd1df4 100644
>>>>> --- a/fs/f2fs/data.c
>>>>> +++ b/fs/f2fs/data.c
>>>>> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>>>>> if ((!cycled && !done) || retry) {
>>>>
>>>> IMO, we add retry logic in wrong place, you can see that cycled value is
>>>> zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
>>>>
>>>> However if retry is true and wbc->range_cyclic is false, then writeback_index
>>>> would be uninitialized variable.
>>>>
>>>> Thoughts?
>>>>
>>>> Thanks,
>>>>
>>>>> cycled = 1;
>>>>> index = 0;
>>>>> - end = writeback_index - 1;
>>>
>>> BTW, I notice that range_cyclic writeback flow was refactored in below commit,
>>> and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
>>> I guess we need follow that change.
>>>
>>> 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>>
>> Is that something like this?
>>
>> ---
>> fs/f2fs/data.c | 11 ++---------
>> 1 file changed, 2 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 48a622b95b76e..28fcdf0d4dcb9 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> pgoff_t index;
>> pgoff_t end; /* Inclusive */
>> pgoff_t done_index;
>> - int cycled;
>> int range_whole = 0;
>> xa_mark_t tag;
>> int nwritten = 0;
>> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> if (wbc->range_cyclic) {
>> writeback_index = mapping->writeback_index; /* prev offset */
>> index = writeback_index;
>> - if (index == 0)
>> - cycled = 1;
>> - else
>> - cycled = 0;
>> end = -1;
>> } else {
>> index = wbc->range_start >> PAGE_SHIFT;
>> end = wbc->range_end >> PAGE_SHIFT;
>> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
>> range_whole = 1;
>> - cycled = 1; /* ignore range_cyclic tests */
>> }
>> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
>> tag = PAGECACHE_TAG_TOWRITE;
>> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> }
>> }
>> #endif
>> - if ((!cycled && !done) || retry) {
>> - cycled = 1;
>> + if (retry) {
>> index = 0;
>> - end = writeback_index - 1;
>> + end = -1;
>> goto retry;
>> }
+ if (wbc->range_cyclic && !done)
+ done_index = 0;
Thanks,
>> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
>> --
>> 2.27.0.rc0.183.gde8f92d652-goog
>>
>
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^ permalink raw reply [flat|nested] 14+ messages in thread* Re: [f2fs-dev] [PATCH] f2fs: fix retry logic in f2fs_write_cache_pages()
@ 2020-06-01 11:43 ` Chao Yu
0 siblings, 0 replies; 14+ messages in thread
From: Chao Yu @ 2020-06-01 11:43 UTC (permalink / raw)
To: Sahitya Tummala, Jaegeuk Kim; +Cc: linux-f2fs-devel, linux-kernel
On 2020/6/1 17:20, Sahitya Tummala wrote:
> Hi Chao,
>
> Can you please help review the diff given by Jaegeuk below?
> If it looks good, I can post a v2.
Oops, I missed to review that patch...
>
> Thanks,
>
> On Thu, May 28, 2020 at 12:18:39PM -0700, Jaegeuk Kim wrote:
>> On 05/28, Chao Yu wrote:
>>> On 2020/5/28 10:45, Chao Yu wrote:
>>>> On 2020/5/27 10:20, Sahitya Tummala wrote:
>>>>> In case a compressed file is getting overwritten, the current retry
>>>>> logic doesn't include the current page to be retried now as it sets
>>>>> the new start index as 0 and new end index as writeback_index - 1.
>>>>> This causes the corresponding cluster to be uncompressed and written
>>>>> as normal pages without compression. Fix this by allowing writeback to
>>>>> be retried for the current page as well (in case of compressed page
>>>>> getting retried due to index mismatch with cluster index). So that
>>>>> this cluster can be written compressed in case of overwrite.
>>>>>
>>>>> Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
>>>>> ---
>>>>> 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 4af5fcd..bfd1df4 100644
>>>>> --- a/fs/f2fs/data.c
>>>>> +++ b/fs/f2fs/data.c
>>>>> @@ -3024,7 +3024,7 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>>>>> if ((!cycled && !done) || retry) {
>>>>
>>>> IMO, we add retry logic in wrong place, you can see that cycled value is
>>>> zero only if wbc->range_cyclic is true, in that case writeback_index is valid.
>>>>
>>>> However if retry is true and wbc->range_cyclic is false, then writeback_index
>>>> would be uninitialized variable.
>>>>
>>>> Thoughts?
>>>>
>>>> Thanks,
>>>>
>>>>> cycled = 1;
>>>>> index = 0;
>>>>> - end = writeback_index - 1;
>>>
>>> BTW, I notice that range_cyclic writeback flow was refactored in below commit,
>>> and skeleton of f2fs.writepages was copied from mm/page-writeback.c::write_cache_pages(),
>>> I guess we need follow that change.
>>>
>>> 64081362e8ff ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock")
>>
>> Is that something like this?
>>
>> ---
>> fs/f2fs/data.c | 11 ++---------
>> 1 file changed, 2 insertions(+), 9 deletions(-)
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 48a622b95b76e..28fcdf0d4dcb9 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -2861,7 +2861,6 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> pgoff_t index;
>> pgoff_t end; /* Inclusive */
>> pgoff_t done_index;
>> - int cycled;
>> int range_whole = 0;
>> xa_mark_t tag;
>> int nwritten = 0;
>> @@ -2879,17 +2878,12 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> if (wbc->range_cyclic) {
>> writeback_index = mapping->writeback_index; /* prev offset */
>> index = writeback_index;
>> - if (index == 0)
>> - cycled = 1;
>> - else
>> - cycled = 0;
>> end = -1;
>> } else {
>> index = wbc->range_start >> PAGE_SHIFT;
>> end = wbc->range_end >> PAGE_SHIFT;
>> if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
>> range_whole = 1;
>> - cycled = 1; /* ignore range_cyclic tests */
>> }
>> if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
>> tag = PAGECACHE_TAG_TOWRITE;
>> @@ -3054,10 +3048,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
>> }
>> }
>> #endif
>> - if ((!cycled && !done) || retry) {
>> - cycled = 1;
>> + if (retry) {
>> index = 0;
>> - end = writeback_index - 1;
>> + end = -1;
>> goto retry;
>> }
+ if (wbc->range_cyclic && !done)
+ done_index = 0;
Thanks,
>> if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
>> --
>> 2.27.0.rc0.183.gde8f92d652-goog
>>
>
^ permalink raw reply [flat|nested] 14+ messages in thread