fsverity: stop using PG_error to track error status

As a step towards freeing the PG_error flag for other uses, change ext4
and f2fs to stop using PG_error to track verity errors.  Instead, if a
verity error occurs, just mark the whole bio as failed.  The coarser
granularity isn't really a problem since it isn't any worse than what
the block layer provides, and errors from a multi-page readahead aren't
reported to applications unless a single-page read fails too.

f2fs supports compression, which makes the f2fs changes a bit more
complicated than desired, but the basic premise still works.

Note: there are still a few uses of PageError in f2fs, but they are on
the write path, so they are unrelated and this patch doesn't touch them.

Reviewed-by: Chao Yu <chao@kernel.org>
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221129070401.156114-1-ebiggers@kernel.org

1 files changed, 31 insertions, 33 deletions

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index d315c2de136f..2b7a5cc4ed66 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1711,50 +1711,27 @@ static void f2fs_put_dic(struct decompress_io_ctx *dic, bool in_task)
 	}
 }
 
-/*
- * Update and unlock the cluster's pagecache pages, and release the reference to
- * the decompress_io_ctx that was being held for I/O completion.
- */
-static void __f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
-				bool in_task)
+static void f2fs_verify_cluster(struct work_struct *work)
 {
+	struct decompress_io_ctx *dic =
+		container_of(work, struct decompress_io_ctx, verity_work);
 	int i;
 
+	/* Verify, update, and unlock the decompressed pages. */
 	for (i = 0; i < dic->cluster_size; i++) {
 		struct page *rpage = dic->rpages[i];
 
 		if (!rpage)
 			continue;
 
-		/* PG_error was set if verity failed. */
-		if (failed || PageError(rpage)) {
-			ClearPageUptodate(rpage);
-			/* will re-read again later */
-			ClearPageError(rpage);
-		} else {
+		if (fsverity_verify_page(rpage))
 			SetPageUptodate(rpage);
-		}
+		else
+			ClearPageUptodate(rpage);
 		unlock_page(rpage);
 	}
 
-	f2fs_put_dic(dic, in_task);
-}
-
-static void f2fs_verify_cluster(struct work_struct *work)
-{
-	struct decompress_io_ctx *dic =
-		container_of(work, struct decompress_io_ctx, verity_work);
-	int i;
-
-	/* Verify the cluster's decompressed pages with fs-verity. */
-	for (i = 0; i < dic->cluster_size; i++) {
-		struct page *rpage = dic->rpages[i];
-
-		if (rpage && !fsverity_verify_page(rpage))
-			SetPageError(rpage);
-	}
-
-	__f2fs_decompress_end_io(dic, false, true);
+	f2fs_put_dic(dic, true);
 }
 
 /*
@@ -1764,6 +1741,8 @@ static void f2fs_verify_cluster(struct work_struct *work)
 void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
 				bool in_task)
 {
+	int i;
+
 	if (!failed && dic->need_verity) {
 		/*
 		 * Note that to avoid deadlocks, the verity work can't be done
@@ -1773,9 +1752,28 @@ void f2fs_decompress_end_io(struct decompress_io_ctx *dic, bool failed,
 		 */
 		INIT_WORK(&dic->verity_work, f2fs_verify_cluster);
 		fsverity_enqueue_verify_work(&dic->verity_work);
-	} else {
-		__f2fs_decompress_end_io(dic, failed, in_task);
+		return;
+	}
+
+	/* Update and unlock the cluster's pagecache pages. */
+	for (i = 0; i < dic->cluster_size; i++) {
+		struct page *rpage = dic->rpages[i];
+
+		if (!rpage)
+			continue;
+
+		if (failed)
+			ClearPageUptodate(rpage);
+		else
+			SetPageUptodate(rpage);
+		unlock_page(rpage);
 	}
+
+	/*
+	 * Release the reference to the decompress_io_ctx that was being held
+	 * for I/O completion.
+	 */
+	f2fs_put_dic(dic, in_task);
 }
 
 /*