Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg...

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

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 1e59ed575cc991819a980b1ea6facd9d8a683995..cf54bdfee334287383e7b63badc5a3683e2edf4f 100644 (file)
--- 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 9c4f4b1c97f84aad654dd8f70cf5231c78a6fc52..9ea0cde3fa9e0ffe7aebc28940293c422ae75a63 100644 (file)
--- 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 359494ea1bde2a4df306004155cd31cdd6e89252..21f46fb3a10193a966c18879c5bea794fd9a494e 100644 (file)
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -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
+ * 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 b82a83aba31185870b132d4e8d7c99bb975fc0b6..9a9367c0c0768bff86bfa9ddde5ff85574497292 100644 (file)
--- 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 742c40583159cba7736d87c4ec3bc5a7250613d5..efe68148f621959beb28987dd9430fff289f583f 100644 (file)
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -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;