1 files changed, 16 insertions, 8 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 98d95bb5f253..e73051099368 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1036,11 +1036,13 @@ out:
  * on error we return an unlocked page and the error value
  * on success we return a locked page and 0
  */
-static int prepare_uptodate_page(struct page *page, u64 pos)
+static int prepare_uptodate_page(struct page *page, u64 pos,
+                                 bool force_uptodate)
 {
         int ret = 0;
 
-        if ((pos & (PAGE_CACHE_SIZE - 1)) && !PageUptodate(page)) {
+        if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
+            !PageUptodate(page)) {
                 ret = btrfs_readpage(NULL, page);
                 if (ret)
                         return ret;
@@ -1061,7 +1063,7 @@ static int prepare_uptodate_page(struct page *page, u64 pos)
 static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
                          struct page **pages, size_t num_pages,
                          loff_t pos, unsigned long first_index,
-                         size_t write_bytes)
+                         size_t write_bytes, bool force_uptodate)
 {
         struct extent_state *cached_state = NULL;
         int i;
@@ -1086,10 +1088,11 @@ again:
                 }
 
                 if (i == 0)
-                        err = prepare_uptodate_page(pages[i], pos);
+                        err = prepare_uptodate_page(pages[i], pos,
+                                                    force_uptodate);
                 if (i == num_pages - 1)
                         err = prepare_uptodate_page(pages[i],
-                                                    pos + write_bytes);
+                                                    pos + write_bytes, false);
                 if (err) {
                         page_cache_release(pages[i]);
                         faili = i - 1;
@@ -1158,6 +1161,7 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
         size_t num_written = 0;
         int nrptrs;
         int ret = 0;
+        bool force_page_uptodate = false;
 
         nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
                      PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
@@ -1200,7 +1204,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                  * contents of pages from loop to loop
                  */
                 ret = prepare_pages(root, file, pages, num_pages,
-                                    pos, first_index, write_bytes);
+                                    pos, first_index, write_bytes,
+                                    force_page_uptodate);
                 if (ret) {
                         btrfs_delalloc_release_space(inode,
                                         num_pages << PAGE_CACHE_SHIFT);
@@ -1217,12 +1222,15 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                 if (copied < write_bytes)
                         nrptrs = 1;
 
-                if (copied == 0)
+                if (copied == 0) {
+                        force_page_uptodate = true;
                         dirty_pages = 0;
-                else
+                } else {
+                        force_page_uptodate = false;
                         dirty_pages = (copied + offset +
                                        PAGE_CACHE_SIZE - 1) >>
                                        PAGE_CACHE_SHIFT;
+                }
 
                 /*
                  * If we had a short copy we need to release the excess delaloc