2019-08-16 06:18:46

by Chandan Rajendra

[permalink] [raw]
Subject: [PATCH V4 4/8] fs/buffer.c: add decryption support via read_callbacks

This commit sets up read_callbacks context for buffer heads whose
contents need to be decrypted on endio.

Signed-off-by: Chandan Rajendra <[email protected]>
---
fs/buffer.c | 33 ++++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index ce357602f471..96c4c9840746 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -45,6 +45,7 @@
#include <linux/bit_spinlock.h>
#include <linux/pagevec.h>
#include <linux/sched/mm.h>
+#include <linux/read_callbacks.h>
#include <trace/events/block.h>

static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);
@@ -245,11 +246,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block)
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)
+void end_buffer_async_read(struct buffer_head *bh, int uptodate)
{
unsigned long flags;
struct buffer_head *first;
@@ -257,8 +254,6 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
struct page *page;
int page_uptodate = 1;

- BUG_ON(!buffer_async_read(bh));
-
page = bh->b_page;
if (uptodate) {
set_buffer_uptodate(bh);
@@ -306,6 +301,17 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
return;
}

+/*
+ * I/O completion handler for block_read_full_page(). Pages are unlocked
+ * after the I/O completes and the read callbacks (if any) have executed.
+ */
+static void __end_buffer_async_read(struct buffer_head *bh, int uptodate)
+{
+ BUG_ON(!buffer_async_read(bh));
+
+ read_callbacks_endio_bh(bh, uptodate, end_buffer_async_read);
+}
+
/*
* Completion handler for block_write_full_page() - pages which are unlocked
* during I/O, and which have PageWriteback cleared upon I/O completion.
@@ -378,7 +384,7 @@ EXPORT_SYMBOL(end_buffer_async_write);
*/
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;
set_buffer_async_read(bh);
}

@@ -2293,10 +2299,15 @@ int block_read_full_page(struct page *page, get_block_t *get_block)
*/
for (i = 0; i < nr; i++) {
bh = arr[i];
- if (buffer_uptodate(bh))
- end_buffer_async_read(bh, 1);
- else
+ if (buffer_uptodate(bh)) {
+ __end_buffer_async_read(bh, 1);
+ } else {
+ if (WARN_ON(read_callbacks_setup_bh(inode, bh))) {
+ __end_buffer_async_read(bh, 0);
+ continue;
+ }
submit_bh(REQ_OP_READ, 0, bh);
+ }
}
return 0;
}
--
2.19.1