--- zzzz-none-000/linux-5.4.213/fs/buffer.c	2022-09-15 10:04:56.000000000 +0000
+++ miami-7690-761/linux-5.4.213/fs/buffer.c	2024-05-29 11:20:02.000000000 +0000
@@ -47,6 +47,7 @@
 #include <linux/pagevec.h>
 #include <linux/sched/mm.h>
 #include <trace/events/block.h>
+#include <linux/fscrypt.h>
 
 static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
 static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
@@ -246,10 +247,6 @@
 	return ret;
 }
 
-/*
- * I/O completion handler for block_read_full_page() - pages
- * which come unlocked at the end of I/O.
- */
 static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
 {
 	unsigned long flags;
@@ -307,6 +304,47 @@
 	return;
 }
 
+struct decrypt_bh_ctx {
+	struct work_struct work;
+	struct buffer_head *bh;
+};
+
+static void decrypt_bh(struct work_struct *work)
+{
+	struct decrypt_bh_ctx *ctx =
+		container_of(work, struct decrypt_bh_ctx, work);
+	struct buffer_head *bh = ctx->bh;
+	int err;
+
+	err = fscrypt_decrypt_pagecache_blocks(bh->b_page, bh->b_size,
+					       bh_offset(bh));
+	end_buffer_async_read(bh, err == 0);
+	kfree(ctx);
+}
+
+/*
+ * I/O completion handler for block_read_full_page() - pages
+ * which come unlocked at the end of I/O.
+ */
+static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
+{
+	/* Decrypt if needed */
+	if (uptodate && IS_ENABLED(CONFIG_FS_ENCRYPTION) &&
+	    IS_ENCRYPTED(bh->b_page->mapping->host) &&
+	    S_ISREG(bh->b_page->mapping->host->i_mode)) {
+		struct decrypt_bh_ctx *ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
+
+		if (ctx) {
+			INIT_WORK(&ctx->work, decrypt_bh);
+			ctx->bh = bh;
+			fscrypt_enqueue_decrypt_work(&ctx->work);
+			return;
+		}
+		uptodate = 0;
+	}
+	end_buffer_async_read(bh, uptodate);
+}
+
 /*
  * Completion handler for block_write_full_page() - pages which are unlocked
  * during I/O, and which have PageWriteback cleared upon I/O completion.
@@ -379,7 +417,7 @@
  */
 static void mark_buffer_async_read(struct buffer_head *bh)
 {
-	bh->b_end_io = end_buffer_async_read;
+	bh->b_end_io = end_buffer_async_read_io;
 	set_buffer_async_read(bh);
 }