2 files changed, 19 insertions, 7 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 8eb1f3c1b647..870150547f5c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1291,7 +1291,8 @@ 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 inode *inode,
+                                 struct page *page, u64 pos,
                                  bool force_uptodate)
 {
         int ret = 0;
@@ -1306,6 +1307,10 @@ static int prepare_uptodate_page(struct page *page, u64 pos,
                         unlock_page(page);
                         return -EIO;
                 }
+                if (page->mapping != inode->i_mapping) {
+                        unlock_page(page);
+                        return -EAGAIN;
+                }
         }
         return 0;
 }
@@ -1324,6 +1329,7 @@ static noinline int prepare_pages(struct inode *inode, struct page **pages,
         int faili;
 
         for (i = 0; i < num_pages; i++) {
+again:
                 pages[i] = find_or_create_page(inode->i_mapping, index + i,
                                                mask | __GFP_WRITE);
                 if (!pages[i]) {
@@ -1333,13 +1339,17 @@ static noinline int prepare_pages(struct inode *inode, struct page **pages,
                 }
 
                 if (i == 0)
-                        err = prepare_uptodate_page(pages[i], pos,
+                        err = prepare_uptodate_page(inode, pages[i], pos,
                                                     force_uptodate);
-                if (i == num_pages - 1)
-                        err = prepare_uptodate_page(pages[i],
+                if (!err && i == num_pages - 1)
+                        err = prepare_uptodate_page(inode, pages[i],
                                                     pos + write_bytes, false);
                 if (err) {
                         page_cache_release(pages[i]);
+                        if (err == -EAGAIN) {
+                                err = 0;
+                                goto again;
+                        }
                         faili = i - 1;
                         goto fail;
                 }
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 7a91770d8bb2..f331ef7d573a 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2972,7 +2972,7 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
                      u64 cont1_bytes, u64 min_bytes)
 {
         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
-        struct btrfs_free_space *entry;
+        struct btrfs_free_space *entry = NULL;
         int ret = -ENOSPC;
         u64 bitmap_offset = offset_to_bitmap(ctl, offset);
 
@@ -2983,8 +2983,10 @@ setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
          * The bitmap that covers offset won't be in the list unless offset
          * is just its start offset.
          */
-        entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
-        if (entry->offset != bitmap_offset) {
+        if (!list_empty(bitmaps))
+                entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
+
+        if (!entry || entry->offset != bitmap_offset) {
                 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
                 if (entry && list_empty(&entry->list))
                         list_add(&entry->list, bitmaps);