[PATCH 4/4] writeback: introduce super_operations->write_metadata
From: Josef Bacik
Now that we have metadata counters in the VM, we need to provide a way to kick
writeback on dirty metadata. Introduce super_operations->write_metadata. This
allows file systems to deal with writing back any dirty metadata we need based
on the writeback needs of the system. Since there is no inode to key off of we
need a list in the bdi for dirty super blocks to be added. From there we can
find any dirty sb's on the bdi we are currently doing writeback on and call into
their ->write_metadata callback.
Signed-off-by: Josef Bacik
Reviewed-by: Jan Kara
Reviewed-by: Tejun Heo
Signed-off-by: Nikolay Borisov
---
Changes since previous posting [1] :
- Forward ported to 4.12-rc6 kernel
I've retained the review-by tags since I didn't introduce any changes.
[1] https://patchwork.kernel.org/patch/9395213/
fs/fs-writeback.c| 72
fs/super.c | 7
include/linux/backing-dev-defs.h | 2 ++
include/linux/fs.h | 4 +++
mm/backing-dev.c | 2 ++
5 files changed, 81 insertions(+), 6 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c7b33d124f3d..9fa2b6cfaf5b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1479,6 +1479,31 @@ static long writeback_chunk_size(struct bdi_writeback
*wb,
return pages;
}
+static long writeback_sb_metadata(struct super_block *sb,
+ struct bdi_writeback *wb,
+ struct wb_writeback_work *work)
+{
+ struct writeback_control wbc = {
+ .sync_mode = work->sync_mode,
+ .tagged_writepages = work->tagged_writepages,
+ .for_kupdate= work->for_kupdate,
+ .for_background = work->for_background,
+ .for_sync = work->for_sync,
+ .range_cyclic = work->range_cyclic,
+ .range_start= 0,
+ .range_end = LLONG_MAX,
+ };
+ long write_chunk;
+
+ write_chunk = writeback_chunk_size(wb, work);
+ wbc.nr_to_write = write_chunk;
+ sb->s_op->write_metadata(sb, &wbc);
+ work->nr_pages -= write_chunk - wbc.nr_to_write;
+
+ return write_chunk - wbc.nr_to_write;
+}
+
+
/*
* Write a portion of b_io inodes which belong to @sb.
*
@@ -1505,6 +1530,7 @@ static long writeback_sb_inodes(struct super_block *sb,
unsigned long start_time = jiffies;
long write_chunk;
long wrote = 0; /* count both pages and inodes */
+ bool done = false;
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -1621,12 +1647,18 @@ static long writeback_sb_inodes(struct super_block *sb,
* background threshold and other termination conditions.
*/
if (wrote) {
- if (time_is_before_jiffies(start_time + HZ / 10UL))
- break;
- if (work->nr_pages <= 0)
+ if (time_is_before_jiffies(start_time + HZ / 10UL) ||
+ work->nr_pages <= 0) {
+ done = true;
break;
+ }
}
}
+ if (!done && sb->s_op->write_metadata) {
+ spin_unlock(&wb->list_lock);
+ wrote += writeback_sb_metadata(sb, wb, work);
+ spin_lock(&wb->list_lock);
+ }
return wrote;
}
@@ -1635,6 +1667,7 @@ static long __writeback_inodes_wb(struct bdi_writeback
*wb,
{
unsigned long start_time = jiffies;
long wrote = 0;
+ bool done = false;
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -1654,12 +1687,39 @@ static long __writeback_inodes_wb(struct bdi_writeback
*wb,
/* refer to the same tests at the end of writeback_sb_inodes */
if (wrote) {
- if (time_is_before_jiffies(start_time + HZ / 10UL))
- break;
- if (work->nr_pages <= 0)
+ if (time_is_before_jiffies(start_time + HZ / 10UL) ||
+ work->nr_pages <= 0) {
+ done = true;
break;
+ }
}
}
+
+ if (!done && wb_stat(wb, WB_METADATA_DIRTY_BYTES)) {
+ LIST_HEAD(list);
+
+ spin_unlock(&wb->list_lock);
+ spin_lock(&wb->bdi->sb_list_lock);
+ list_splice_init(&wb->bdi->dirty_sb_list, &list);
+ while (!list_empty(&list)) {
+ struct super_block *sb;
+
+ sb = list_first_entry(&list, struct super_block,
+
Re: [PATCH 4/4] writeback: introduce super_operations->write_metadata
On 09/22/2016 07:48 AM, Jan Kara wrote:
On Tue 20-09-16 16:57:48, Josef Bacik wrote:
Now that we have metadata counters in the VM, we need to provide a way to kick
writeback on dirty metadata. Introduce super_operations->write_metadata. This
allows file systems to deal with writing back any dirty metadata we need based
on the writeback needs of the system. Since there is no inode to key off of we
need a list in the bdi for dirty super blocks to be added. From there we can
find any dirty sb's on the bdi we are currently doing writeback on and call into
their ->write_metadata callback.
Signed-off-by: Josef Bacik
---
fs/fs-writeback.c| 72
fs/super.c | 7
include/linux/backing-dev-defs.h | 2 ++
include/linux/fs.h | 4 +++
mm/backing-dev.c | 2 ++
5 files changed, 81 insertions(+), 6 deletions(-)
...
+ if (!done && sb->s_op->write_metadata) {
+ spin_unlock(&wb->list_lock);
+ wrote += writeback_sb_metadata(sb, wb, work);
+ spin_unlock(&wb->list_lock);
^^^
spin_lock();
Otherwise the patch looks good to me. So feel free to add:
Reviewed-by: Jan Kara
after fixing the above.
Yup I hit this as soon as I started testing so I'll go ahead and add your
reviewed-by. I'll resend the whole series after these changes have actually
gone through some testing since it seems you are happy with the overall
direction. Thanks,
Josef
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 4/4] writeback: introduce super_operations->write_metadata
On Tue 20-09-16 16:57:48, Josef Bacik wrote:
> Now that we have metadata counters in the VM, we need to provide a way to kick
> writeback on dirty metadata. Introduce super_operations->write_metadata.
> This
> allows file systems to deal with writing back any dirty metadata we need based
> on the writeback needs of the system. Since there is no inode to key off of
> we
> need a list in the bdi for dirty super blocks to be added. From there we can
> find any dirty sb's on the bdi we are currently doing writeback on and call
> into
> their ->write_metadata callback.
>
> Signed-off-by: Josef Bacik
> ---
> fs/fs-writeback.c| 72
>
> fs/super.c | 7
> include/linux/backing-dev-defs.h | 2 ++
> include/linux/fs.h | 4 +++
> mm/backing-dev.c | 2 ++
> 5 files changed, 81 insertions(+), 6 deletions(-)
>
...
> + if (!done && sb->s_op->write_metadata) {
> + spin_unlock(&wb->list_lock);
> + wrote += writeback_sb_metadata(sb, wb, work);
> + spin_unlock(&wb->list_lock);
^^^
spin_lock();
Otherwise the patch looks good to me. So feel free to add:
Reviewed-by: Jan Kara
after fixing the above.
Honza
--
Jan Kara
SUSE Labs, CR
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH 4/4] writeback: introduce super_operations->write_metadata
Now that we have metadata counters in the VM, we need to provide a way to kick
writeback on dirty metadata. Introduce super_operations->write_metadata. This
allows file systems to deal with writing back any dirty metadata we need based
on the writeback needs of the system. Since there is no inode to key off of we
need a list in the bdi for dirty super blocks to be added. From there we can
find any dirty sb's on the bdi we are currently doing writeback on and call into
their ->write_metadata callback.
Signed-off-by: Josef Bacik
---
fs/fs-writeback.c| 72
fs/super.c | 7
include/linux/backing-dev-defs.h | 2 ++
include/linux/fs.h | 4 +++
mm/backing-dev.c | 2 ++
5 files changed, 81 insertions(+), 6 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index aafdb11..8cd072e 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1464,6 +1464,31 @@ static long writeback_chunk_size(struct bdi_writeback
*wb,
return pages;
}
+static long writeback_sb_metadata(struct super_block *sb,
+ struct bdi_writeback *wb,
+ struct wb_writeback_work *work)
+{
+ struct writeback_control wbc = {
+ .sync_mode = work->sync_mode,
+ .tagged_writepages = work->tagged_writepages,
+ .for_kupdate= work->for_kupdate,
+ .for_background = work->for_background,
+ .for_sync = work->for_sync,
+ .range_cyclic = work->range_cyclic,
+ .range_start= 0,
+ .range_end = LLONG_MAX,
+ };
+ long write_chunk;
+
+ write_chunk = writeback_chunk_size(wb, work);
+ wbc.nr_to_write = write_chunk;
+ sb->s_op->write_metadata(sb, &wbc);
+ work->nr_pages -= write_chunk - wbc.nr_to_write;
+
+ return write_chunk - wbc.nr_to_write;
+}
+
+
/*
* Write a portion of b_io inodes which belong to @sb.
*
@@ -1490,6 +1515,7 @@ static long writeback_sb_inodes(struct super_block *sb,
unsigned long start_time = jiffies;
long write_chunk;
long wrote = 0; /* count both pages and inodes */
+ bool done = false;
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -1606,12 +1632,18 @@ static long writeback_sb_inodes(struct super_block *sb,
* background threshold and other termination conditions.
*/
if (wrote) {
- if (time_is_before_jiffies(start_time + HZ / 10UL))
- break;
- if (work->nr_pages <= 0)
+ if (time_is_before_jiffies(start_time + HZ / 10UL) ||
+ work->nr_pages <= 0) {
+ done = true;
break;
+ }
}
}
+ if (!done && sb->s_op->write_metadata) {
+ spin_unlock(&wb->list_lock);
+ wrote += writeback_sb_metadata(sb, wb, work);
+ spin_unlock(&wb->list_lock);
+ }
return wrote;
}
@@ -1620,6 +1652,7 @@ static long __writeback_inodes_wb(struct bdi_writeback
*wb,
{
unsigned long start_time = jiffies;
long wrote = 0;
+ bool done = false;
while (!list_empty(&wb->b_io)) {
struct inode *inode = wb_inode(wb->b_io.prev);
@@ -1639,12 +1672,39 @@ static long __writeback_inodes_wb(struct bdi_writeback
*wb,
/* refer to the same tests at the end of writeback_sb_inodes */
if (wrote) {
- if (time_is_before_jiffies(start_time + HZ / 10UL))
- break;
- if (work->nr_pages <= 0)
+ if (time_is_before_jiffies(start_time + HZ / 10UL) ||
+ work->nr_pages <= 0) {
+ done = true;
break;
+ }
}
}
+
+ if (!done && wb_stat(wb, WB_METADATA_DIRTY_BYTES)) {
+ LIST_HEAD(list);
+
+ spin_unlock(&wb->list_lock);
+ spin_lock(&wb->bdi->sb_list_lock);
+ list_splice_init(&wb->bdi->dirty_sb_list, &list);
+ while (!list_empty(&list)) {
+ struct super_block *sb;
+
+ sb = list_first_entry(&list, struct super_block,
+ s_bdi_dirty_list);
+ list_move_tail(&sb->s_bdi_dirty_list,
+ &wb->bdi->dirty_sb_list);
+ if (!sb->s_op->write_metadata)
+ continue;
+
