Btrfs: Search data ordered extents first for checksums on read

[linux-2.6-block.git] / fs / btrfs / inode.c

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 28e667052ec3224da1fd9ecd8695193c9bb5b993..0e90315ea803288a37816fe8a73655adb126c066 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -611,22 +611,25 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
            btrfs_test_flag(inode, NODATASUM))
                return 0;
 
+       /*
+        * It is possible there is an ordered extent that has
+        * not yet finished for this range in the file.  If so,
+        * that extent will have a csum cached, and it will insert
+        * the sum after all the blocks in the extent are fully
+        * on disk.  So, look for an ordered extent and use the
+        * sum if found.  We have to do this before looking in the
+        * btree because csum items are pre-inserted based on
+        * the file size.  btrfs_lookup_csum might find an item
+        * that still hasn't been fully filled.
+        */
+       ret = btrfs_find_ordered_sum(inode, start, &csum);
+       if (ret == 0)
+               goto found;
+
+       ret = 0;
        path = btrfs_alloc_path();
-       mutex_lock(&BTRFS_I(inode)->csum_mutex);
        item = btrfs_lookup_csum(NULL, root, path, inode->i_ino, start, 0);
        if (IS_ERR(item)) {
-               /*
-                * It is possible there is an ordered extent that has
-                * not yet finished for this range in the file.  If so,
-                * that extent will have a csum cached, and it will insert
-                * the sum after all the blocks in the extent are fully
-                * on disk.  So, look for an ordered extent and use the
-                * sum if found.
-                */
-               ret = btrfs_find_ordered_sum(inode, start, &csum);
-               if (ret == 0)
-                       goto found;
-
                ret = PTR_ERR(item);
                /* a csum that isn't present is a preallocated region. */
                if (ret == -ENOENT || ret == -EFBIG)
@@ -641,7 +644,6 @@ int btrfs_readpage_io_hook(struct page *page, u64 start, u64 end)
 found:
        set_state_private(io_tree, start, csum);
 out:
-       mutex_unlock(&BTRFS_I(inode)->csum_mutex);
        if (path)
                btrfs_free_path(path);
        return ret;
@@ -1375,7 +1377,7 @@ again:
                }
                if (!PageUptodate(page)) {
                        ret = -EIO;
-                       goto out;
+                       goto out_unlock;
                }
        }
        wait_on_page_writeback(page);
@@ -1406,6 +1408,7 @@ again:
        set_page_dirty(page);
        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
 
+out_unlock:
        unlock_page(page);
        page_cache_release(page);
 out: