Btrfs: fix how we deal with the pages array in the write path

[mirror_ubuntu-artful-kernel.git] / fs / btrfs / file.c

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index f2a80e570a6c286c5ca5d54707c82f8828111c48..24a19c2743ca76e34a700ef990ec28aba36c54c7 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -108,8 +108,6 @@ static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
 {
        size_t i;
        for (i = 0; i < num_pages; i++) {
-               if (!pages[i])
-                       break;
                /* page checked is some magic around finding pages that
                 * have been modified without going through btrfs_set_page_dirty
                 * clear it here
@@ -824,7 +822,6 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
                        return err;
        }
 
-       memset(pages, 0, num_pages * sizeof(struct page *));
 again:
        for (i = 0; i < num_pages; i++) {
                pages[i] = grab_cache_page(inode->i_mapping, index + i);
@@ -930,7 +927,6 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                size_t copied;
 
                WARN_ON(num_pages > nrptrs);
-               memset(pages, 0, sizeof(struct page *) * nrptrs);
 
                /*
                 * Fault pages before locking them in prepare_pages
@@ -946,6 +942,11 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                if (ret)
                        break;
 
+               /*
+                * This is going to setup the pages array with the number of
+                * pages we want, so we don't really need to worry about the
+                * contents of pages from loop to loop
+                */
                ret = prepare_pages(root, file, pages, num_pages,
                                    pos, first_index, last_index,
                                    write_bytes);