ext4: stop looping in ext4_num_dirty_pages when max_pages reached

Today we simply break out of the inner loop when we have accumulated
max_pages; this keeps scanning forwad and doing pagevec_lookup_tag()
in the while (!done) loop, this does potentially a lot of work
with no net effect.

When we have accumulated max_pages, just clean up and return.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4b8debeb3965..d88ba4a9effa 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1207,8 +1207,10 @@ static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
                                 break;
                         idx++;
                         num++;
-                        if (num >= max_pages)
+                        if (num >= max_pages) {
+                                done = 1;
                                 break;
+                        }
                 }
                 pagevec_release(&pvec);
         }