Btrfs: try to drop dead cow pages from ram

Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 18 insertions, 2 deletions

diff --git a/fs/btrfs/TODO b/fs/btrfs/TODO
index 5ff2cef9f02..6a8c8cd03ca 100644
--- a/fs/btrfs/TODO
+++ b/fs/btrfs/TODO
@@ -6,8 +6,7 @@
 * Check compat and incompat flags on the inode
 * Get rid of struct ctree_path, limiting tree levels held at one time
 * Add generation number to key pointer in nodes
-* Add parent pointer back to extent map.
-* Implement real list of pending transactions
+* Add generation number to inode
 * Release
 * Do real tree locking
 * Add extent mirroring (backup copies of blocks)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index aca5802a8a1..afc5267515e 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -291,10 +291,18 @@ static int update_block_group(struct btrfs_trans_handle *trans,
         return 0;
 }
 
+static int try_remove_page(struct address_space *mapping, unsigned long index)
+{
+        int ret;
+        ret = invalidate_mapping_pages(mapping, index, index);
+        return ret;
+}
+
 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                                btrfs_root *root)
 {
         unsigned long gang[8];
+        struct inode *btree_inode = root->fs_info->btree_inode;
         u64 first = 0;
         int ret;
         int i;
@@ -309,6 +317,9 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans, struct
                         first = gang[0];
                 for (i = 0; i < ret; i++) {
                         clear_radix_bit(pinned_radix, gang[i]);
+                        try_remove_page(btree_inode->i_mapping,
+                                        gang[i] << (PAGE_CACHE_SHIFT -
+                                                    btree_inode->i_blkbits));
                 }
         }
         if (root->fs_info->block_group_cache) {
@@ -600,6 +611,12 @@ check_pending:
          */
         btrfs_release_path(root, path);
         BUG_ON(ins->objectid < search_start);
+        if (ins->objectid >= btrfs_super_total_blocks(info->disk_super)) {
+                if (search_start == 0)
+                        return -ENOSPC;
+                search_start = 0;
+                goto check_failed;
+        }
         for (test_block = ins->objectid;
              test_block < ins->objectid + num_blocks; test_block++) {
                 if (test_radix_bit(&info->pinned_radix, test_block)) {