GFS2: Submit all ordered writes in bulk, wait after that

Hi,

This is a new and improved version of the patch set I posted on 14 May.
---
Before this patch, the ordered_write function would submit all the ordered writes with filemap_fdatawrite, which waited for each one to complete before moving on to the next. This patch allows it to submit them all, then wait for them after they're submitted. It also implements Andreas's suggestion to call the filemap functions directly rather than a more complicated ordered_wait. It also does the sorting outside the spin_lock.

Signed-off-by Bob Peterson <[email protected]>

---
 fs/gfs2/log.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

fs/gfs2/log.c +10 -4

index 0248835625f1..c7c4549ba1c9 100644
@@ -22,6 +22,7 @@
 #include <linux/blkdev.h>
 #include <linux/writeback.h>
 #include <linux/list_sort.h>
+#include <linux/fs.h>
 
 #include "gfs2.h"
 #include "incore.h"

@@ -534,22 +535,32 @@ static void gfs2_ordered_write(struct gfs2_sbd *sdp)
 {
        struct gfs2_inode *ip;
        LIST_HEAD(written);
+       struct writeback_control wbc = {
+               .sync_mode = WB_SYNC_NONE,
+               .nr_to_write = LONG_MAX,
+               .range_start = 0,
+               .range_end = LLONG_MAX,
+       };
 
        spin_lock(&sdp->sd_ordered_lock);
-       list_sort(NULL, &sdp->sd_log_le_ordered, &ip_cmp);
        while (!list_empty(&sdp->sd_log_le_ordered)) {
                ip = list_entry(sdp->sd_log_le_ordered.next, struct gfs2_inode, i_ordered);
-               if (ip->i_inode.i_mapping->nrpages == 0) {
+               if (ip->i_inode.i_mapping->nrpages)
+                       list_move(&ip->i_ordered, &written);
+               else {
                        test_and_clear_bit(GIF_ORDERED, &ip->i_flags);
                        list_del(&ip->i_ordered);
-                       continue;
                }
-               list_move(&ip->i_ordered, &written);