Btrfs: tag pages for writeback in sync

Everybody else does this, we need to do it too.  If we're syncing, we need to
tag the pages we're going to write for writeback so we don't end up writing the
same stuff over and over again if somebody is constantly redirtying our file.
This will keep us from having latencies with heavy sync workloads.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index abb922daf1b63a769236f8242373813b9557a6f3..89bbde46bd838817fa74b46c4a1e22fedb95b4f0 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2421,6 +2421,7 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
        pgoff_t index;
        pgoff_t end;            /* Inclusive */
        int scanned = 0;
+       int tag;
 
        pagevec_init(&pvec, 0);
        if (wbc->range_cyclic) {
@@ -2431,11 +2432,16 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
                end = wbc->range_end >> PAGE_CACHE_SHIFT;
                scanned = 1;
        }
+       if (wbc->sync_mode == WB_SYNC_ALL)
+               tag = PAGECACHE_TAG_TOWRITE;
+       else
+               tag = PAGECACHE_TAG_DIRTY;
 retry:
+       if (wbc->sync_mode == WB_SYNC_ALL)
+               tag_pages_for_writeback(mapping, index, end);
        while (!done && !nr_to_write_done && (index <= end) &&
-              (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
-                             PAGECACHE_TAG_DIRTY, min(end - index,
-                                 (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
+              (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
+                       min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
                unsigned i;
 
                scanned = 1;