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authorChris Mason <chris.mason@oracle.com>2010-10-29 11:16:17 -0400
committerChris Mason <chris.mason@oracle.com>2010-10-29 11:25:29 -0400
commit3259f8bed2f0f57c2fdcdac1b510c3fa319ef97e (patch)
tree5f06f6c83413ca2fc7aec85ba0811a8c91904097 /fs/fs-writeback.c
parentcb44921a09221f0a90217b44044448f63190f3e5 (diff)
Add new functions for triggering inode writeback
When btrfs is running low on metadata space, it needs to force delayed allocation pages to disk. It currently does this with a suboptimal walk of a private list of inodes with delayed allocation, and it would be much better if we used the generic flusher threads. writeback_inodes_sb_if_idle would be ideal, but it waits for the flusher thread to start IO on all the dirty pages in the FS before it returns. This adds variants of writeback_inodes_sb* that allow the caller to control how many pages get sent down. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/fs-writeback.c')
-rw-r--r--fs/fs-writeback.c52
1 files changed, 42 insertions, 10 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ab38fef1c9a1..1e23c33ea5cf 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1069,33 +1069,44 @@ static void wait_sb_inodes(struct super_block *sb)
}
/**
- * writeback_inodes_sb - writeback dirty inodes from given super_block
+ * writeback_inodes_sb_nr - writeback dirty inodes from given super_block
* @sb: the superblock
+ * @nr: the number of pages to write
*
* Start writeback on some inodes on this super_block. No guarantees are made
* on how many (if any) will be written, and this function does not wait
- * for IO completion of submitted IO. The number of pages submitted is
- * returned.
+ * for IO completion of submitted IO.
*/
-void writeback_inodes_sb(struct super_block *sb)
+void writeback_inodes_sb_nr(struct super_block *sb, unsigned long nr)
{
- unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
- unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
DECLARE_COMPLETION_ONSTACK(done);
struct wb_writeback_work work = {
.sb = sb,
.sync_mode = WB_SYNC_NONE,
.done = &done,
+ .nr_pages = nr,
};
WARN_ON(!rwsem_is_locked(&sb->s_umount));
-
- work.nr_pages = nr_dirty + nr_unstable +
- (inodes_stat.nr_inodes - inodes_stat.nr_unused);
-
bdi_queue_work(sb->s_bdi, &work);
wait_for_completion(&done);
}
+EXPORT_SYMBOL(writeback_inodes_sb_nr);
+
+/**
+ * writeback_inodes_sb - writeback dirty inodes from given super_block
+ * @sb: the superblock
+ *
+ * Start writeback on some inodes on this super_block. No guarantees are made
+ * on how many (if any) will be written, and this function does not wait
+ * for IO completion of submitted IO.
+ */
+void writeback_inodes_sb(struct super_block *sb)
+{
+ return writeback_inodes_sb_nr(sb, global_page_state(NR_FILE_DIRTY) +
+ global_page_state(NR_UNSTABLE_NFS) +
+ (inodes_stat.nr_inodes - inodes_stat.nr_unused));
+}
EXPORT_SYMBOL(writeback_inodes_sb);
/**
@@ -1118,6 +1129,27 @@ int writeback_inodes_sb_if_idle(struct super_block *sb)
EXPORT_SYMBOL(writeback_inodes_sb_if_idle);
/**
+ * writeback_inodes_sb_if_idle - start writeback if none underway
+ * @sb: the superblock
+ * @nr: the number of pages to write
+ *
+ * Invoke writeback_inodes_sb 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)
+{
+ if (!writeback_in_progress(sb->s_bdi)) {
+ down_read(&sb->s_umount);
+ writeback_inodes_sb_nr(sb, nr);
+ up_read(&sb->s_umount);
+ return 1;
+ } else
+ return 0;
+}
+EXPORT_SYMBOL(writeback_inodes_sb_nr_if_idle);
+
+/**
* sync_inodes_sb - sync sb inode pages
* @sb: the superblock
*