2 writeback fixes

- fix negative (setpoint - dirty) in 32bit archs
 - use down_read_trylock() in writeback_inodes_sb(_nr)_if_idle()
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Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux

Pull writeback fixes from Wu Fengguang:
 "Two writeback fixes

   - fix negative (setpoint - dirty) in 32bit archs

   - use down_read_trylock() in writeback_inodes_sb(_nr)_if_idle()"

* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
  Negative (setpoint-dirty) in bdi_position_ratio()
  vfs: re-implement writeback_inodes_sb(_nr)_if_idle() and rename them
This commit is contained in:
Linus Torvalds 2013-02-28 13:21:44 -08:00
commit de1a2262b0
5 changed files with 37 additions and 59 deletions

View File

@ -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

View File

@ -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)) {

View File

@ -1344,47 +1344,43 @@ 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
* @sb: the superblock
* @reason: reason why some writeback work was initiated
*
* Invoke writeback_inodes_sb 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)
{
if (!writeback_in_progress(sb->s_bdi)) {
down_read(&sb->s_umount);
writeback_inodes_sb(sb, reason);
up_read(&sb->s_umount);
return 1;
} else
return 0;
}
EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
/**
* writeback_inodes_sb_nr_if_idle - start writeback if none underway
* try_to_writeback_inodes_sb_nr - 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
* @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_nr_if_idle(struct super_block *sb,
unsigned long nr,
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_nr(sb, nr, 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_nr_if_idle);
EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr);
/**
* try_to_writeback_inodes_sb - try to start writeback if none underway
* @sb: the superblock
* @reason: reason why some writeback work was initiated
*
* Implement by try_to_writeback_inodes_sb_nr()
* Returns 1 if writeback was started, 0 if not.
*/
int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason)
{
return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason);
}
EXPORT_SYMBOL(try_to_writeback_inodes_sb);
/**
* sync_inodes_sb - sync sb inode pages

View File

@ -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);

View File

@ -696,7 +696,7 @@ 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;