Update Linux to v5.10.157

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.157.tar.xz

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I7b30d9e98d8c465d6b44de8e7433b4a40b3289ba
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 62784b9..9a8dc16 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -1075,7 +1075,9 @@
 	extref = btrfs_lookup_inode_extref(NULL, root, path, name, namelen,
 					   inode_objectid, parent_objectid, 0,
 					   0);
-	if (!IS_ERR_OR_NULL(extref)) {
+	if (IS_ERR(extref)) {
+		return PTR_ERR(extref);
+	} else if (extref) {
 		u32 item_size;
 		u32 cur_offset = 0;
 		unsigned long base;
@@ -5335,6 +5337,18 @@
 	}
 
 	/*
+	 * For symlinks, we must always log their content, which is stored in an
+	 * inline extent, otherwise we could end up with an empty symlink after
+	 * log replay, which is invalid on linux (symlink(2) returns -ENOENT if
+	 * one attempts to create an empty symlink).
+	 * We don't need to worry about flushing delalloc, because when we create
+	 * the inline extent when the symlink is created (we never have delalloc
+	 * for symlinks).
+	 */
+	if (S_ISLNK(inode->vfs_inode.i_mode))
+		inode_only = LOG_INODE_ALL;
+
+	/*
 	 * a brute force approach to making sure we get the most uptodate
 	 * copies of everything.
 	 */
@@ -5724,7 +5738,7 @@
 			}
 
 			ctx->log_new_dentries = false;
-			if (type == BTRFS_FT_DIR || type == BTRFS_FT_SYMLINK)
+			if (type == BTRFS_FT_DIR)
 				log_mode = LOG_INODE_ALL;
 			ret = btrfs_log_inode(trans, root, BTRFS_I(di_inode),
 					      log_mode, ctx);