[GIT PULL] writeback fixes for v3.9-rc1
From: Fengguang Wu
Date: Wed Feb 27 2013 - 20:44:48 EST
Hi Linus,
Here are 2 writeback fixes.
Please be prepared for a merge conflict in fs/btrfs/extent-tree.c as
occured/resolved in linux-next's merge commit 6ae374247bfd8 ("Merge
remote-tracking branch 'writeback/writeback-for-next'").
Thanks,
Fengguang
---
The following changes since commit 9931faca02c604c22335f5a935a501bb2ace6e20:
Linux 3.8-rc3 (2013-01-09 18:59:55 -0800)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux.git tags/writeback-fixes
for you to fetch changes up to ed84825b785ceb932af7dd5aa08614801721320b:
Negative (setpoint-dirty) in bdi_position_ratio() (2013-01-24 22:22:22 +0800)
----------------------------------------------------------------
2 writeback fixes
- fix negative (setpoint - dirty) in 32bit archs
- use down_read_trylock() in writeback_inodes_sb(_nr)_if_idle()
----------------------------------------------------------------
Miao Xie (1):
vfs: re-implement writeback_inodes_sb(_nr)_if_idle() and rename them
paul.szabo@xxxxxxxxxxxxx (1):
Negative (setpoint-dirty) in bdi_position_ratio()
(Yeah I'm aware of that broken author name and tried to fix it, however just
found that the fixing commit lies in "* (no branch)" and now it's a bit late
to update the "writeback-for-next" branch).
fs/btrfs/extent-tree.c | 20 +++-----------------
fs/ext4/inode.c | 8 ++------
fs/fs-writeback.c | 44 ++++++++++++++++++++------------------------
include/linux/writeback.h | 6 +++---
mm/page-writeback.c | 2 +-
5 files changed, 29 insertions(+), 51 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 521e9d4..f31abb1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3689,20 +3689,6 @@ static int can_overcommit(struct btrfs_root *root,
return 0;
}
-static int writeback_inodes_sb_nr_if_idle_safe(struct super_block *sb,
- unsigned long nr_pages,
- enum wb_reason reason)
-{
- if (!writeback_in_progress(sb->s_bdi) &&
- down_read_trylock(&sb->s_umount)) {
- writeback_inodes_sb_nr(sb, nr_pages, reason);
- up_read(&sb->s_umount);
- return 1;
- }
-
- return 0;
-}
-
/*
* shrink metadata reservation for delalloc
*/
@@ -3735,9 +3721,9 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig,
while (delalloc_bytes && loops < 3) {
max_reclaim = min(delalloc_bytes, to_reclaim);
nr_pages = max_reclaim >> PAGE_CACHE_SHIFT;
- writeback_inodes_sb_nr_if_idle_safe(root->fs_info->sb,
- nr_pages,
- WB_REASON_FS_FREE_SPACE);
+ try_to_writeback_inodes_sb_nr(root->fs_info->sb,
+ nr_pages,
+ WB_REASON_FS_FREE_SPACE);
/*
* We need to wait for the async pages to actually start before
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index cbfe13b..5f6eef7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2512,12 +2512,8 @@ static int ext4_nonda_switch(struct super_block *sb)
/*
* Start pushing delalloc when 1/2 of free blocks are dirty.
*/
- if (dirty_blocks && (free_blocks < 2 * dirty_blocks) &&
- !writeback_in_progress(sb->s_bdi) &&
- down_read_trylock(&sb->s_umount)) {
- writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
- up_read(&sb->s_umount);
- }
+ if (dirty_blocks && (free_blocks < 2 * dirty_blocks))
+ try_to_writeback_inodes_sb(sb, WB_REASON_FS_FREE_SPACE);
if (2 * free_blocks < 3 * dirty_blocks ||
free_blocks < (dirty_blocks + EXT4_FREECLUSTERS_WATERMARK)) {
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 310972b..ad3cc46 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1332,47 +1332,43 @@ void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
EXPORT_SYMBOL(writeback_inodes_sb);
/**
- * writeback_inodes_sb_if_idle - start writeback if none underway
+ * try_to_writeback_inodes_sb_nr - try to start writeback if none underway
* @sb: the superblock
- * @reason: reason why some writeback work was initiated
+ * @nr: the number of pages to write
+ * @reason: the reason of writeback
*
- * Invoke writeback_inodes_sb if no writeback is currently underway.
+ * Invoke writeback_inodes_sb_nr if no writeback is currently underway.
* Returns 1 if writeback was started, 0 if not.
*/
-int writeback_inodes_sb_if_idle(struct super_block *sb, enum wb_reason reason)
+int try_to_writeback_inodes_sb_nr(struct super_block *sb,
+ unsigned long nr,
+ enum wb_reason reason)
{
- if (!writeback_in_progress(sb->s_bdi)) {
- down_read(&sb->s_umount);
- writeback_inodes_sb(sb, reason);
- up_read(&sb->s_umount);
+ if (writeback_in_progress(sb->s_bdi))
return 1;
- } else
+
+ if (!down_read_trylock(&sb->s_umount))
return 0;
+
+ writeback_inodes_sb_nr(sb, nr, reason);
+ up_read(&sb->s_umount);
+ return 1;
}
-EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
+EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr);
/**
- * writeback_inodes_sb_nr_if_idle - start writeback if none underway
+ * try_to_writeback_inodes_sb - try to start writeback if none underway
* @sb: the superblock
- * @nr: the number of pages to write
* @reason: reason why some writeback work was initiated
*
- * Invoke writeback_inodes_sb if no writeback is currently underway.
+ * Implement by try_to_writeback_inodes_sb_nr()
* Returns 1 if writeback was started, 0 if not.
*/
-int writeback_inodes_sb_nr_if_idle(struct super_block *sb,
- unsigned long nr,
- enum wb_reason reason)
+int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
- if (!writeback_in_progress(sb->s_bdi)) {
- down_read(&sb->s_umount);
- writeback_inodes_sb_nr(sb, nr, reason);
- up_read(&sb->s_umount);
- return 1;
- } else
- return 0;
+ return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
-EXPORT_SYMBOL(writeback_inodes_sb_nr_if_idle);
+EXPORT_SYMBOL(try_to_writeback_inodes_sb);
/**
* sync_inodes_sb - sync sb inode pages
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index b82a83a..9a9367c 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -87,9 +87,9 @@ int inode_wait(void *);
void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
-int writeback_inodes_sb_if_idle(struct super_block *, enum wb_reason reason);
-int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr,
- enum wb_reason reason);
+int try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
+int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
+ enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages,
enum wb_reason reason);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0713bfb..1534ebd 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -692,7 +692,7 @@ static unsigned long bdi_position_ratio(struct backing_dev_info *bdi,
* => fast response on large errors; small oscillation near setpoint
*/
setpoint = (freerun + limit) / 2;
- x = div_s64((setpoint - dirty) << RATELIMIT_CALC_SHIFT,
+ x = div_s64(((s64)setpoint - (s64)dirty) << RATELIMIT_CALC_SHIFT,
limit - setpoint + 1);
pos_ratio = x;
pos_ratio = pos_ratio * x >> RATELIMIT_CALC_SHIFT;
--
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