Btrfs: use the inode's mapping mask for allocating pages

Johannes pointed out we were allocating only kernel pages for doing writes,
which is kind of a big deal if you are on 32bit and have more than a gig of ram.
So fix our allocations to use the mapping's gfp but still clear __GFP_FS so we
don't re-enter.  Thanks,

Reported-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Josef Bacik <josef@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2947e94947b5..88e3956be57d 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3282,6 +3282,7 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
         pgoff_t index = from >> PAGE_CACHE_SHIFT;
         unsigned offset = from & (PAGE_CACHE_SIZE-1);
         struct page *page;
+        gfp_t mask = btrfs_alloc_write_mask(mapping);
         int ret = 0;
         u64 page_start;
         u64 page_end;
@@ -3294,7 +3295,7 @@ static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
 
         ret = -ENOMEM;
 again:
-        page = find_or_create_page(mapping, index, GFP_NOFS);
+        page = find_or_create_page(mapping, index, mask);
         if (!page) {
                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
                 goto out;